WO2022083668A1

WO2022083668A1 - Use of a chimeric co-stimulatory receptor for cell therapy

Info

Publication number: WO2022083668A1
Application number: PCT/CN2021/125149
Authority: WO
Inventors: Jintao GUO; Wang ZHANG; Ruidong HAO; Shu Wu
Original assignee: Nanjing Legend Biotech Co., Ltd.
Priority date: 2020-10-21
Filing date: 2021-10-21
Publication date: 2022-04-28

Abstract

A system for inducing activity of an immune cell, comprising a chimeric co-stimulatory receptor comprising a first intracellular domain comprising a first co-stimulatory domain devoid of a signaling domain of CD3 zeta; and a chimeric antigen receptor comprising a second intracellular domain comprising a signaling domain and a second co-stimulatory domain.

Description

USE OF A CHIMERIC CO-STIMULATORY RECEPTOR FOR CELL THERAPY

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority of the International Application No. PCT/CN2020/122594 filed on October 21, 2020, the content of which is incorporated herein by reference in its entirety.

SEQUENCE LISTING

This application incorporates by reference a Sequence Listing submitted with this application in a text format, entitled “P10951-PCT. 211019. L2-W20235WO_SEQ_LISTING, ” created on October 13, 2021 having a size of 166,763 bytes.

1. FIELD

Provided herein, in some embodiments, are engineered immune cells expressing a chimeric antigen receptor (CAR) and a chimeric co-stimulatory receptor, and uses thereof for treating a disease or disorder such as cancer.

2. BACKGROUND

Adoptive transfer of T cells represents an emerging innovative therapeutic strategy against cancer. For instance, T cells engineered with chimeric antigen receptor (CAR) induce potent clinical response in patients with blood cancers, demonstrating promising superior prognosis comparing with conventional therapies. However, patients with bulky solid tumors are less likely to obtain the same benefits from current CAR-T cell therapies. Among several factors that contribute to the lack of efficacy, by far the most important one is restricted T-cell expansion in vivo. There is still a need for optimizing the current CAR design to enhance T cell expansion and anti-tumor efficacies without compromising for toxic side effects.

3. SUMMARY

In one aspect, provided herein is a system for inducing activity of an immune cell, comprising: (a) a chimeric co-stimulatory receptor comprising (i) a first extracellular domain capable of binding to a first epitope, (ii) a first transmembrane domain, and (iii) a first intracellular domain comprising a first co-stimulatory domain devoid of a signaling domain of CD3 zeta; and (b) a chimeric antigen receptor (CAR) comprising (i) a second extracellular domain capable of binding to a second epitope, (ii) a second transmembrane domain, and (iii) a second intracellular domain comprising a signaling domain and a second co-stimulatory domain. In some embodiments, the second intracellular domain further comprises a third co-stimulatory domain.

In another aspect, provided herein is a host cell expressing the system provided herein. In some embodiments, the host cell is an immune cell. In some embodiments, the immune cell is a lymphocyte. In some embodiments, the lymphocyte is a T cell.

In another aspect, provided herein is a composition comprising one or more polynucleotides that encodes: (a) a chimeric co-stimulatory receptor provided herein; and (b) a CAR provided herein.

In another aspect, provided herein is a method for making a CAR-T cell, comprising introducing into a T cell: (a) a first polynucleotide encoding a chimeric co-stimulatory receptor provided herein; and (b) a second polynucleotide encoding a CAR provided herein.

In another aspect, provided herein is a CAR-T cell produced according to the method provided herein.

In another aspect, provided herein is a CAR-T cell expressing: (a) a chimeric co-stimulatory receptor provided herein; and (b) a CAR provided herein.

In yet another aspect, provided herein is a pharmaceutical composition, comprising the host cell or the CAR-T cell provided herein and a pharmaceutically acceptable excipient.

In yet another aspect, provided herein is a method for treating a disease or disorder in a subject comprising administering to the subject a therapeutically effective amount of the host cell, the CAR-T cell, or the pharmaceutical composition provided herein.

In yet another aspect, provided herein is a method of inducing activity of an immune cell, comprising: (a) expressing a chimeric co-stimulatory receptor provided herein; (b) expressing a CAR provided herein; and (c) contacting a target cell with the immune cell.

In another aspect, provided herein is a system for inducing activity of an immune cell, comprising: (a) a chimeric co-stimulatory receptor provided herein; and (b) a modified or an unmodified T cell receptor (TCR) complex.

In yet another aspect, provided herein is a host cell expressing the system provided herein. In some embodiments, the host cell is an αβ T cell. In some embodiments, the host cell exhibits specific binding to two antigens simultaneously present in a target cell.

In yet another aspect, provided herein is an immune cell comprising a system provided herein. In some embodiments, the antigen binding domain linked to the CAR primarily mediates interaction between the immune cell and a target cell, and the antigen binding domain linked to the TCR complex primarily mediates an immune cell activity when the interaction between the immune cell and the target cell takes place. In some embodiments, the immune cell activity is selected from the group consisting of: clonal expansion of the immune cell; cytokine release by the immune cell; cytotoxicity of the immune cell; proliferation of the immune cell; differentiation, dedifferentiation or transdifferentiation of the immune cell; movement and/or trafficking of the immune cell; exhaustion and/or reactivation of the immune cell; and release of other intercellular molecules, metabolites, chemical compounds, or combinations thereof by the immune cell. In some embodiments, the immune cell is an αβ T cell.

In another aspect, provided herein is a population of immune cells comprising an immune cell expressing the system provided herein.

In yet another aspect, provided herein is a method of inducing an activity of an immune cell, comprising: (a) expressing a system provided herein in an immune cell; and (b) contacting a target cell with the immune cell.

In another aspect, provided herein is a composition comprising one or more polynucleotides that encodes: (a) a chimeric co-stimulatory receptor provided herein; and (b) a modified or an unmodified T cell receptor (TCR) complex provided herein.

In yet another aspect, provided herein is a method of producing a modified immune cell, comprising introducing into an immune cell: (a) a first polynucleotide encoding a chimeric co-stimulatory receptor provided herein; and (b) a second polynucleotide encoding a modified or an unmodified T cell receptor (TCR) complex provided herein.

In yet another aspect, provided herein is a pharmaceutical composition comprising the host cell, the immune cell, the population of immune cells or the modified immune cell produced according to the method provided herein, and a pharmaceutically acceptable excipient.

In yet another aspect, provided herein is a method for treating a disease or disorder in a subject comprising administering to the subject a therapeutically effective amount of the host cell, the immune cell, the population of immune cells, or the modified immune cell produced according to the method provided herein, or the pharmaceutical composition provided herein.

4. BRIEF DESCRIPTION OF THE FIGURES

FIGs. 1A-1G: Illustrations of conventional CAR-T, 3 ^rd generation CAR-T, chimeric co-stimulatory receptor, mutated chimeric co-stimulatory receptor, chimeric co-stimulatory receptor armored CAR-T, mutated chimeric co-stimulatory receptor armored CAR-T and truncated chimeric co-stimulatory receptor armored CAR-T structures.

FIG. 2: Expression of GPC2 in target cells SH-SY5Y, LAN-1, HEK293/GPC2, LAN-1/GPC2 ^KO and HEK293 (log shift of positive expression is indicated) .

FIG. 3: Expression of GD2 in target cells SH-SY5Y, LAN-1, HEK293/GPC2, LAN-1/GPC2 ^KO and HEK293 (log shift of positive expression is indicated) .

FIG. 4: Expression of DLL3 in target cells SHP-77, DMS-79, HEK293 and SH-SY5Y (log shift of positive expression is indicated) .

FIG. 5: Expression of CD326 in target cells SHP-77, DMS-79, HEK293 and SH-SY5Y (log shift of positive expression is indicated) .

FIG. 6: Expression of GD2 in target cells SHP-77, DMS-79, HEK293 and SH-SY5Y (log shift of positive expression is indicated) .

FIGs. 7A-7E: In vitro CAR-T cell cytotoxicity of GPC2-BBz/GD2-28, GPC2-BBz, GD2-BBz and GD2-28 CAR-T cells.

FIGs. 8A-8E: Level of IFN-γ released from GPC2-BBz/GD2-28, GPC2-BBz, GD2-BBz and GD2-28 CAR-T cells.

FIGs. 9A-9C: In vitro CAR-T cell persistence and expansion of GPC2-BBz/GD2-28, GPC2-BBz, GD2-BBz and GD2-28 CAR-T cells after serial challenge with SH-SY5Y.

FIG. 10: Level of IFN-γ released from serial challenge assay of GPC2-BBz/GD2-28, GPC2-BBz, GD2-BBz and GD2-28 CAR-T cells.

FIG. 11: Levels of 13 cytokines released from serial challenge assay of GPC2-BBz/GD2-28 and GPC2-BBz.

FIG. 12: Experimental design of in vivo efficacy study of GD2 chimeric co-stimulatory receptor armored CAR-T.

FIGs. 13A-13C: In vivo efficacy and kinetics of GD2 chimeric co-stimulatory receptor armored CAR-T cells against a xenograft model of neuroblastoma.

FIG. 14A-14D: In vitro CAR-T cell cytotoxicity of GPC2-BBz/GD2-28, GPC2-BBz/GD2-Δ28 and GPC2-BBz CAR-T cells.

FIG. 15A-15D: Level of IFN-γ released from GPC2-BBz/GD2-28, GPC2-BBz/GD2-Δ28 and GPC2-BBz CAR-T cells.

FIGs. 16A-16C: In vitro CAR-T cell persistence and expansion of GPC2-BBz/GD2-28, GPC2-BBz/GD2-Δ28 and GPC2-BBz CAR-T cells after serial challenge with SH-SY5Y.

FIG. 17: In vitro CAR-T cell cytotoxicity of GPC2-BBz/GD2-28, GPC2-BBz, GPC2-28z and four different 3 ^rd generation GPC2 CAR-T cells.

FIG. 18: Level of IFN-γ released from GPC2-BBz/GD2-28, GPC2-BBz, GPC2-28z and four different 3 ^rd generation GPC2 CAR-T cells.

FIGs. 19A-19C: In vitro CAR-T cell persistence and expansion of GPC2-BBz/GD2-28, GPC2-BBz, GPC2-28z and four different 3 ^rd generation GPC2 CAR-T cells after serial challenge with SH-SY5Y.

FIGs. 20A-20C: In vitro CAR-T cell persistence and expansion of GPC2-BBz/GD2-28, GPC2-28z/GD2-BB, GPC2-BBz, GPC2-28z after serial challenge with SH-SY5Y.

FIGs. 21A-21C: In vitro CAR-T cell persistence and expansion of GPC2-BBz/GD2-28, GPC2-BBz/GD2-2, GPC2-BBz/GD2-ICOS and GPC2-BBz after serial challenge with SH-SY5Y.

FIG. 22: Level of IFN-γ released from GPC2-BBz/GD2-28, GPC2-BBz/GD2-2, GPC2-BBz/GD2-ICOS and GPC2-BBz after serial challenge with SH-SY5Y.

FIG. 23A-23C: In vitro CAR-T cell cytotoxicity of GPC2-BBz/GD2-28, GPC2-BBz and GD2-BBz against SH-SY5Y in presence of Ganglidiomab at various concentrations.

FIG. 24A-24C: In vitro CAR-T cell cytotoxicity of GPC2-BBz/GD2-28, GPC2-BBz and GD2-BBz against SH-SY5Y in presence of mouse IgG2a isotype at various concentrations.

FIG. 25: Expression of MSLN in GPC2-espressing target cells HEK293/GPC2 through RNA electroporation.

FIGs. 26A-26B: In vitro CAR-T cell persistence and expansion of GPC2-BBz after serial challenge with target cells HEK293/GPC2 or HEK293/GPC2 that transfected with various dosage of MSLN mRNA.

FIGs. 27A-27B: In vitro CAR-T cell persistence and expansion of MSLN-BBz after serial challenge with target cells HEK293/GPC2 or HEK293/GPC2 that transfected with various dosage of MSLN mRNA.

FIGs. 28A-28B: In vitro CAR-T cell persistence and expansion of GPC2-BBz/MSLN-28 after serial challenge with target cells HEK293/GPC2 or HEK293/GPC2 that transfected with various dosage of MSLN mRNA.

FIGs. 29A-29B: In vitro T cell persistence and expansion of un-transfected control T cells after serial challenge with target cells HEK293/GPC2 or HEK293/GPC2 that transfected with various dosage of MSLN mRNA.

FIGs. 30A-30D: In vitro CAR-T cell cytotoxicity of DLL3-BBz and DLL3-BBz/GD2-28 CAR-T cells.

FIGs. 31A-31D: Level of IFN-γ released from DLL3-BBz and DLL3-BBz/GD2-28 CAR-T cells.

FIGs. 32A-32D: In vitro CAR-T cell cytotoxicity of DLL3-BBz, DLL3-BBz/DLL3-28 and DLL3-BBz/CD326-28 CAR-T cells.

FIGs. 33A-33D: Level of IFN-γ released from DLL3-BBz, DLL3-BBz/DLL3-28 and DLL3-BBz/CD326-28 CAR-T cells.

FIGs. 34A-34C: In vitro CAR-T cell persistence and expansion of DLL3-BBz, DLL3-BBz/DLL3-28 and DLL3-BBz/CD326-28 CAR-Ts after serial challenge with SHP-77.

FIG. 35: Levels of IFN-γ released from serial challenge assay of DLL3-BBz, DLL3-BBz/DLL3-28 and DLL3-BBz/CD326-28 CAR-Ts.

FIGs. 36A-36D: In vitro CAR-T cell cytotoxicity of GPC2-BBz/MSLN-28, GPC2-BBz/MSLN-28 (C141S, C168S mutant) and GPC2-BBz CAR-T cells.

FIGs. 37A-37D: Level of IFN-γ released from GPC2-BBz/MSLN-28, GPC2-BBz/MSLN-28 (C141S, C168S mutant) and GPC2-BBz CAR-T cells.

FIGs. 38A-38D: In vitro CAR-T cell cytotoxicity of GPC2-BBz/GD2-28, GPC2-BBz/GD2-28 (C141S, C168S mutant) and GPC2-BBz CAR-T cells.

FIGs. 39A-39D: Level of IFN-γ released from GPC2-BBz/GD2-28, GPC2-BBz/GD2-28 (C141S, C168S mutant) and GPC2-BBz CAR-T cells.

FIGs. 40A-40D: In vitro CAR-T cell cytotoxicity of GPC2-BBz/B7-H3-28, GPC2-BBz/B7-H3-28 (C141S, C168S mutant) and GPC2-BBz CAR-T cells.

FIGs. 41A-41D: Level of IFN-γ released from GPC2-BBz/B7-H3-28, GPC2-BBz/B7-H3-28 (C141S, C168S mutant) and GPC2-BBz CAR-T cells.

FIGs. 42A-42D: In vitro T cell persistence and expansion of GPC2-BBz/GD2-28, GPC2-BBz/GD2-28 (C141S, C168S mutant) , GPC2-BBz/B7-H3-28, GPC2-BBz/B7-H3-28 (C141S, C168S mutant) and GPC2-BBz CAR-T cells after serial challenge with target cell SH-SY5Y.

5. DETAILED DESCRIPTION

The present disclosure, among other advantages, solves the problem of lack of T cell expansion and/or lack of efficacy in engineered T cell therapy against solid tumor. As shown in Section 6 below, the combination with a second co-stimulatory signal in T cell activation via the chimeric co-stimulatory receptor provided herein significantly improves sustaining the activity of CAR-T cell against solid tumors.

One of most important factors that contribute to lack of efficacy of CAR-T cell therapies in solid tumors is restricted T-cell expansion in vivo. One means of increasing the effectiveness of targeted T cell therapy of solid tumor is the incorporation of multiple co-stimulatory domains in engineered CAR-T cells, by combining multiple co-stimulatory domains in a single CAR or through the use of two (or more) individual CARs targeting different antigens in a single T cell (see Richards et al., Frontiers in immunology, 9: 2380-2380 (2018) ; Lee et al., The Journal of Immunology, 173 (5) : 3002-3012 (2004) ; Drent et al., Clinical Cancer Research, clincanres. 2559.2018 (2019) ; Collinson-Pautz et al., Leukemia 2019, 33 (9) : 2195-2207 (2019) ; Pulè et al., Molecular Therapy, 12 (5) : 933-941 (2005) ; Hegde et al., Molecular Therapy, 21 (11) : 2087-2101 (2013) ; Ruella et al., The Journal of Clinical Investigation, 126 (10) : 3814-3826 (2016) ; Wilkie et al., Journal of Clinical Immunology, 32 (5) : 1059-1070 (2012) ) . However, a single CAR comprising multiple co-stimulatory domains is demonstrated not very effective (see Section 6.6 below) , possibly due to structural obstacle and that these domains are likely to interfere with each other, thereby reducing the overall effectiveness in stimulating T-cell expansion. Moreover, the dual CAR strategy (i.e., two individual CARs targeting different antigens) exerts cytotoxicity toward tumor and non-tumor cells expressing either of the two targets leading to undesirable off-target toxicity. To solve such problem, split CAR configuration was designed comprising a chimeric co-stimulatory receptor without CD3 ζsignaling domain and a chimeric receptor without a co-stimulatory domain (see Kloss et al., Nature Biotechnology, 31 (1) : 71-75 (2013) ) . However, while it can be useful to avoid the on-target/off-tumor toxicity for the non-tumor specific antigens, this may also allow tumor antigen escape as downregulation of antigen is commonly observed (see Majzner et al., Cancer Discovery, 8 (10) : 1219-1226 (2018) ) . Thus, the currently available approaches have not achieved desirable effectiveness or safety.

In certain aspect, the present disclosure address the above issues by incorporating a chimeric co-stimulator receptor devoid of a primary intracellular signaling domain (such as CD3 ζ endocellular domain) with a CAR containing a costimulatory domain as well as a primary intracellular signaling domain (such as a CD3 ζ endocellular domain) . As shown, this novel CAR-T design synergistically improves CAR-T cells expansion and their anti-tumor functions without causing non-target specific toxicity.

Using the exemplary anti-GD2 antibody or anti-CD326 antibody, the present disclosure demonstrates the chimeric co-stimulatory receptor can be used to provide an additional co-stimulatory signal for enhancement of adoptive immunotherapy. In certain more specific embodiments, the chimeric co-stimulatory receptor provided herein can be used in combination with at least one additional engineered receptor that delivers signals of TCR complex or CD3ζ. For example, as shown in Section 6, under the stress of repeated antigen exposure that T cells will likely encounter within solid malignancies, only GPC2-CAR-T cells co-expressing a GD2 chimeric co-stimulatory receptor or DLL3-CAR-T cells co-expressing a CD326 chimeric co-stimulatory receptor were able to undergo multiple rounds of expansion and retain potent anti-tumor activity. The superiority of GD2 chimeric co-stimulatory receptor armored CAR-T cells was shown in in vivo model in which functional CAR-T administered at sub-optimum dose could, if combined with GD2 chimeric co-stimulatory receptor, sustain the ability to eradicate established tumors.

Another advantage provided by the present disclosure is the target-specific cytotoxicity and the safety of multi-targeted CAR-T cells. For example, unlike the conventional dual CAR or tandem CAR-T cells that exert cytotoxicity toward tumor and non-tumor cells expressing both or one of the targets, chimeric co-stimulatory receptor do not affect the target-specific cytotoxicity of CAR-T cells. As shown in Section 6, GD2 or CD326 chimeric co-stimulatory receptor armored CAR-Ts did not cause non-specific lysis nor cytokine production when co-cultured with GPC2 negative or DLL3 negative target cells.

Furthermore, the well tolerability seen in neuroblastoma and melanoma patients successfully treated with intravascular GD2 CAR-T cell infusions (see, e.g., Gargett et al., Mol. Ther. 24 (6) : 1135-1149 (2016) ; Pule et al., Nature Medicine 14 (11) : 1264-1270 (2008) ; and Heczey et al., Mol. Ther. 25 (9) : 2214-2224 (2017) ) , together with the observation that GD2 chimeric co-stimulatory receptor functionally enhanced GPC2 CAR-T cells without causing weight loss and other severe adverse events in our xenograft neuroblastoma model, also suggests a low risk for adverse events if CAR-T cells and GD2 chimeric co-stimulatory receptor combination strategy was used for neuroblastoma treatment. In addition, there was no evidence that GD2 chimeric co-stimulatory receptor alone could induce antigen-independent and antigen-dependent proliferation in our serial challenge assay.

5.1. Definitions

Techniques and procedures described or referenced herein include those that are generally well understood and/or commonly employed using conventional methodology by those skilled in the art, such as, for example, the widely utilized methodologies described in Sambrook et al., Molecular Cloning: A Laboratory Manual (3d ed. 2001) ; Current Protocols in Molecular Biology (Ausubel et al. eds., 2003) ; Therapeutic Monoclonal Antibodies: From Bench to Clinic (An ed. 2009) ; Monoclonal Antibodies: Methods and Protocols (Albitar ed. 2010) ; and Antibody Engineering Vols 1 and 2 (Kontermann and Dübel eds., 2d ed. 2010) . Unless otherwise defined herein, technical and scientific terms used in the present description have the meanings that are commonly understood by those of ordinary skill in the art. For purposes of interpreting this specification, the following description of terms will apply and whenever appropriate, terms used in the singular will also include the plural and vice versa. In the event that any description of a term set forth conflicts with any document incorporated herein by reference, the description of the term set forth below shall control.

The term “antibody, ” “immunoglobulin, ” or “Ig” is used interchangeably herein, and is used in the broadest sense and specifically covers, for example, monoclonal antibodies (including agonist, antagonist, neutralizing antibodies, full length or intact monoclonal antibodies) , antibody compositions with polyepitopic or monoepitopic specificity, polyclonal or monovalent antibodies, multivalent antibodies, multispecific antibodies (e.g., bispecific antibodies so long as they exhibit the desired biological activity) , formed from at least two intact antibodies, single chain antibodies, and fragments thereof (e.g., domain antibodies) , as described below. An antibody can be human, humanized, chimeric and/or affinity matured, as well as an antibody from other species, for example, mouse, rabbit, llama, etc. The term “antibody” is intended to include a polypeptide product of B cells within the immunoglobulin class of polypeptides that is able to bind to a specific molecular antigen and is composed of two identical pairs of polypeptide chains, wherein each pair has one heavy chain (about 50-70 kDa) and one light chain (about 25 kDa) , each amino-terminal portion of each chain includes a variable region of about 100 to about 130 or more amino acids, and each carboxy-terminal portion of each chain includes a constant region. See, e.g., Antibody Engineering (Borrebaeck ed., 2d ed. 1995) ; and Kuby, Immunology (3d ed. 1997) . Antibodies also include, but are not limited to, synthetic antibodies, recombinantly produced antibodies, single domain antibodies including from Camelidae species (e.g., llama or alpaca) or their humanized variants, intrabodies, anti-idiotypic (anti-Id) antibodies, and functional fragments (e.g., antigen-binding fragments) of any of the above, which refers to a portion of an antibody heavy or light chain polypeptide that retains some or all of the binding activity of the antibody from which the fragment was derived. Non-limiting examples of functional fragments (e.g., antigen-binding fragments) include single-chain Fvs (scFv) (e.g., including monospecific, bispecific, etc. ) , Fab fragments, F (ab’) fragments, F (ab) ₂ fragments, F (ab’) ₂ fragments, disulfide-linked Fvs (dsFv) , Fd fragments, Fv fragments, diabody, triabody, tetrabody, and minibody. In particular, antibodies provided herein include immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, for example, antigen-binding domains or molecules that contain an antigen-binding site that binds to an antigen (e.g., one or more CDRs of an antibody) . Such antibody fragments can be found in, for example, Harlow and Lane, Antibodies: A Laboratory Manual (1989) ; Mol. Biology and Biotechnology: A Comprehensive Desk Reference (Myers ed., 1995) ; Huston et al., 1993, Cell Biophysics 22: 189-224; Plückthun and Skerra, 1989, Meth. Enzymol. 178: 497-515; and Day, Advanced Immunochemistry (2d ed. 1990) . The antibodies provided herein can be of any class (e.g., IgG, IgE, IgM, IgD, and IgA) or any subclass (e.g., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2) of immunoglobulin molecule. Antibodies may be agonistic antibodies or antagonistic antibodies _. Antibodies may be neither agonistic nor antagonistic.

An “antigen” is a structure to which a binding polypeptide or polypeptide complex (such as an antibody or fragment thereof, a ligand, a receptor, etc. ) can selectively bind. A target antigen may be a polypeptide, carbohydrate, nucleic acid, lipid, hapten, or other naturally occurring or synthetic compound. In some embodiments, the target antigen is a polypeptide. In certain embodiments, an antigen is associated with a cell, for example, is present on or in a cell.

An “intact” antibody is one comprising an antigen-binding site as well as a CL and at least heavy chain constant regions, CH1, CH2 and CH3. The constant regions may include human constant regions or amino acid sequence variants thereof. In certain embodiments, an intact antibody has one or more effector functions.

“Single-chain Fv” also abbreviated as “sFv” or “scFv” are antibody fragments that comprise the VH and VL antibody domains connected into a single polypeptide chain. Preferably, the sFv polypeptide further comprises a polypeptide linker between the VH and VL domains which enables the sFv to form the desired structure for antigen binding. For a review of the sFv, see Pluckthun in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Moore eds., Springer-Verlag, New York, pp. 269-315 (1994) .

“Single domain antibody” or “sdAb” as used herein refers to a single monomeric variable antibody domain and which is capable of antigen binding. Single domain antibodies include VHH domains as described herein. Examples of single domain antibodies include, but are not limited to, antibodies naturally devoid of light chains such as those from Camelidae species (e.g., llama) , single domain antibodies derived from conventional 4-chain antibodies, engineered antibodies and single domain scaffolds other than those derived from antibodies. Single domain antibodies may be derived from any species including, but not limited to mouse, human, camel, llama, goat, rabbit, and bovine. For example, a single domain antibody can be derived from antibodies raised in Camelidae species, for example in camel, llama, dromedary, alpaca and guanaco, as described herein. Other species besides Camelidae may produce heavy chain antibodies naturally devoid of light chain; VHHs derived from such other species are within the scope of the disclosure. In some embodiments, the single domain antibody (e.g., VHH) provided herein has a structure of FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4. Single domain antibodies may be genetically fused or chemically conjugated to another molecule (e.g., an agent) as described herein. Single domain antibodies may be part of a bigger binding molecule (e.g., a multispecific antibody or a chimeric antigen receptor) .

The terms “binds” or “binding” refer to an interaction between molecules including, for example, to form a complex. Interactions can be, for example, non-covalent interactions including hydrogen bonds, ionic bonds, hydrophobic interactions, and/or van der Waals interactions. A complex can also include the binding of two or more molecules held together by covalent or non-covalent bonds, interactions, or forces. The strength of the total non-covalent interactions between a single antigen-binding site on an antibody and a single epitope of a target molecule, such as an antigen, is the affinity of the antibody or functional fragment for that epitope. The ratio of dissociation rate (koff) to association rate (kon) of a binding molecule (e.g., an antibody) to a monovalent antigen (koff/kon) is the dissociation constant KD, which is inversely related to affinity. The lower the KD value, the higher the affinity of the antibody. The value of KD varies for different complexes of antibody and antigen and depends on both kon and koff. The dissociation constant KD for an antibody provided herein can be determined using any method provided herein or any other method well known to those skilled in the art. The affinity at one binding site does not always reflect the true strength of the interaction between an antibody and an antigen. When complex antigens containing multiple, repeating antigenic determinants, such as a polyvalent antigen, come in contact with antibodies containing multiple binding sites, the interaction of antibody with antigen at one site will increase the probability of a reaction at a second site. The strength of such multiple interactions between a multivalent antibody and antigen is called the avidity.

In connection with the binding molecules described herein terms such as “bind to, ” “that specifically bind to, ” and analogous terms are also used interchangeably herein and refer to binding molecules of antigen binding domains that specifically bind to an antigen, such as a polypeptide. A binding molecule or antigen binding domain that binds to or specifically binds to an antigen can be identified, for example, by immunoassays,

or other techniques known to those of skill in the art. In some embodiments, a binding molecule or antigen binding domain binds to or specifically binds to an antigen when it binds to an antigen with higher affinity than to any cross-reactive antigen as determined using experimental techniques, such as radioimmunoassay (RIA) and enzyme linked immunosorbent assay (ELISA) . Typically, a specific or selective reaction will be at least twice background signal or noise and may be more than 10 times background. See, e.g., Fundamental Immunology 332-36 (Paul ed., 2d ed. 1989) for a discussion regarding binding specificity. In certain embodiments, the extent of binding of a binding molecule or antigen binding domain to a “non-target” protein is less than about 10%of the binding of the binding molecule or antigen binding domain to its particular target antigen, for example, as determined by FACS analysis or RIA. A binding molecule or antigen binding domain that binds to an antigen includes one that is capable of binding the antigen with sufficient affinity such that the binding molecule is useful, for example, as a therapeutic and/or diagnostic agent in targeting the antigen. In certain embodiments, a binding molecule or antigen binding domain that binds to an antigen has a dissociation constant (KD) of less than or equal to 1μM, 800 nM, 600 nM, 550 nM, 500 nM, 300 nM, 250 nM, 100 nM, 50 nM, 10 nM, 5 nM, 4 nM, 3 nM, 2 nM, 1 nM, 0.9 nM, 0.8 nM, 0.7 nM, 0.6 nM, 0.5 nM, 0.4 nM, 0.3 nM, 0.2 nM, or 0.1 nM. In certain embodiments, a binding molecule or antigen binding domain binds to an epitope of an antigen that is conserved among the antigen from different species.

In certain embodiments, the binding molecules or antigen binding domains can comprise “chimeric” sequences in which a portion of the heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain (s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (see U.S. Pat. No. 4,816,567; and Morrison et al., 1984, Proc. Natl. Acad. Sci. USA 81: 6851-55) . Chimeric sequences may include humanized sequences.

In certain embodiments, the binding molecules or antigen binding domains can comprise portions of “humanized” forms of nonhuman (e.g., camelid, murine, non-human primate) antibodies that include sequences from human immunoglobulins (e.g., recipient antibody) in which the native CDR residues are replaced by residues from the corresponding CDR of a nonhuman species (e.g., donor antibody) such as camelid, mouse, rat, rabbit, or nonhuman primate having the desired specificity, affinity, and capacity. In some instances, one or more FR region residues of the human immunoglobulin sequences are replaced by corresponding nonhuman residues. Furthermore, humanized antibodies can comprise residues that are not found in the recipient antibody or in the donor antibody. These modifications are made to further refine antibody performance. A humanized antibody heavy or light chain can comprise substantially all of at least one or more variable regions, in which all or substantially all of the CDRs correspond to those of a nonhuman immunoglobulin and all or substantially all of the FRs are those of a human immunoglobulin sequence. In certain embodiments, the humanized antibody will comprise at least a portion of an immunoglobulin constant region (Fc) , typically that of a human immunoglobulin. For further details, see, Jones et al., Nature 321: 522-25 (1986) ; Riechmann et al., Nature 332: 323-29 (1988) ; Presta, Curr. Op. Struct. Biol. 2: 593-96 (1992) ; Carter et al., Proc. Natl. Acad. Sci. USA 89: 4285-89 (1992) ; U.S. Pat. Nos: 6,800,738; 6,719,971; 6,639,055; 6,407,213; and 6,054,297.

In certain embodiments, the binding molecules or antigen binding domains can comprise portions of a “fully human antibody” or “human antibody, ” wherein the terms are used interchangeably herein and refer to an antibody that comprises a human variable region and, for example, a human constant region. The binding molecules may comprise a single domain antibody sequence. In specific embodiments, the terms refer to an antibody that comprises a variable region and constant region of human origin. “Fully human” antibodies, in certain embodiments, can also encompass antibodies which bind polypeptides and are encoded by nucleic acid sequences which are naturally occurring somatic variants of human germline immunoglobulin nucleic acid sequence. The term “fully human antibody” includes antibodies having variable and constant regions corresponding to human germline immunoglobulin sequences as described by Kabat et al. (See Kabat et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242) . A “human antibody” is one that possesses an amino acid sequence which corresponds to that of an antibody produced by a human and/or has been made using any of the techniques for making human antibodies. This definition of a human antibody specifically excludes a humanized antibody comprising non-human antigen-binding residues. Human antibodies can be produced using various techniques known in the art, including phage-display libraries (Hoogenboom and Winter, J. Mol. Biol. 227: 381 (1991) ; Marks et al., J. Mol. Biol. 222: 581 (1991) ) and yeast display libraries (Chao et al., Nature Protocols 1: 755-68 (2006) ) . Also available for the preparation of human monoclonal antibodies are methods described in Cole et al., Monoclonal Antibodies and Cancer Therapy 77 (1985) ; Boerner et al., J. Immunol. 147 (1) : 86-95 (1991) ; and van Dijk and van de Winkel, Curr. Opin. Pharmacol. 5: 368-74 (2001) . Human antibodies can be prepared by administering the antigen to a transgenic animal that has been modified to produce such antibodies in response to antigenic challenge, but whose endogenous loci have been disabled, e.g., mice (see, e.g., Jakobovits, Curr. Opin. Biotechnol. 6 (5) : 561-66 (1995) ; Brüggemann and Taussing, Curr. Opin. Biotechnol. 8 (4) : 455-58 (1997) ; and U.S. Pat. Nos. 6,075,181 and 6,150,584 regarding XENOMOUSETM technology) . See also, for example, Li et al., Proc. Natl. Acad. Sci. USA 103: 3557-62 (2006) regarding human antibodies generated via a human B-cell hybridoma technology.

In certain embodiments, the binding molecules or antigen binding domains can comprise portions of a “recombinant human antibody, ” wherein the phrase includes human antibodies that are prepared, expressed, created or isolated by recombinant means, such as antibodies expressed using a recombinant expression vector transfected into a host cell, antibodies isolated from a recombinant, combinatorial human antibody library, antibodies isolated from an animal (e.g., a mouse or cow) that is transgenic and/or transchromosomal for human immunoglobulin genes (see, e.g., Taylor, L. D. et al., Nucl. Acids Res. 20: 6287-6295 (1992) ) or antibodies prepared, expressed, created or isolated by any other means that involves splicing of human immunoglobulin gene sequences to other DNA sequences. Such recombinant human antibodies can have variable and constant regions derived from human germline immunoglobulin sequences (See Kabat, E. A. et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242) . In certain embodiments, however, such recombinant human antibodies are subjected to in vitro mutagenesis (or, when an animal transgenic for human Ig sequences is used, in vivo somatic mutagenesis) and thus the amino acid sequences of the VH and VL regions of the recombinant antibodies are sequences that, while derived from and related to human germline VH and VL sequences, may not naturally exist within the human antibody germline repertoire in vivo.

In certain embodiments, the binding molecules or antigen binding domains can comprise a portion of a “monoclonal antibody, ” wherein the term as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, e.g., the individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present in minor amounts or well-known post-translational modifications such as amino acid iomerizatio or deamidation, methionine oxidation or asparagine or glutamine deamidation, each monoclonal antibody will typically recognize a single epitope on the antigen. In specific embodiments, a “monoclonal antibody, ” as used herein, is an antibody produced by a single hybridoma or other cell. The term “monoclonal” is not limited to any particular method for making the antibody. For example, the monoclonal antibodies useful in the present disclosure may be prepared by the hybridoma methodology first described by Kohler et al., Nature 256: 495 (1975) , or may be made using recombinant DNA methods in bacterial or eukaryotic animal or plant cells (see, e.g., U.S. Pat. No. 4,816,567) . The “monoclonal antibodies” may also be isolated from phage antibody libraries using the techniques described in Clackson et al., Nature 352: 624-28 (1991) and Marks et al., J. Mol. Biol. 222: 581-97 (1991) , for example. Other methods for the preparation of clonal cell lines and of monoclonal antibodies expressed thereby are well known in the art. See, e.g., Short Protocols in Molecular Biology (Ausubel et al. eds., 5th ed. 2002) .

A typical 4-chain antibody unit is a heterotetrameric glycoprotein composed of two identical light (L) chains and two identical heavy (H) chains. In the case of IgGs, the 4-chain unit is generally about 150,000 daltons. Each L chain is linked to an H chain by one covalent disulfide bond, while the two H chains are linked to each other by one or more disulfide bonds depending on the H chain isotype. Each H and L chain also has regularly spaced intrachain disulfide bridges. Each H chain has at the N-terminus, a variable domain (VH) followed by three constant domains (CH) for each of the α and γ chains and four CH domains for μ and ε isotypes. Each L chain has at the N-terminus, a variable domain (VL) followed by a constant domain (CL) at its other end. The VL is aligned with the VH, and the CL is aligned with the first constant domain of the heavy chain (CH1) . Particular amino acid residues are believed to form an interface between the light chain and heavy chain variable domains. The pairing of a VH and VL together forms a single antigen-binding site. For the structure and properties of the different classes of antibodies, see, for example, Basic and Clinical Immunology 71 (Stites et al. eds., 8th ed. 1994) ; and Immunobiology (Janeway et al. eds., 5th ed. 2001) .

The term “Fab” or “Fab region” refers to an antibody region that binds to antigens. A conventional IgG usually comprises two Fab regions, each residing on one of the two arms of the Y-shaped IgG structure. Each Fab region is typically composed of one variable region and one constant region of each of the heavy and the light chain. More specifically, the variable region and the constant region of the heavy chain in a Fab region are VH and CH1 regions, and the variable region and the constant region of the light chain in a Fab region are VL and CL regions. The VH, CH1, VL, and CL in a Fab region can be arranged in various ways to confer an antigen binding capability according to the present disclosure. For example, VH and CH1 regions can be on one polypeptide, and VL and CL regions can be on a separate polypeptide, similarly to a Fab region of a conventional IgG. Alternatively, VH, CH1, VL and CL regions can all be on the same polypeptide and oriented in different orders as described in more detail the sections below.

The term “variable region, ” “variable domain, ” “V region, ” or “V domain” refers to a portion of the light or heavy chains of an antibody that is generally located at the amino-terminal of the light or heavy chain and has a length of about 120 to 130 amino acids in the heavy chain and about 100 to 110 amino acids in the light chain, and are used in the binding and specificity of each particular antibody for its particular antigen. The variable region of the heavy chain may be referred to as “VH. ” The variable region of the light chain may be referred to as “VL. ” The term “variable” refers to the fact that certain segments of the variable regions differ extensively in sequence among antibodies. The V region mediates antigen binding and defines specificity of a particular antibody for its particular antigen. However, the variability is not evenly distributed across the 110-amino acid span of the variable regions. Instead, the V regions consist of less variable (e.g., relatively invariant) stretches called framework regions (FRs) of about 15-30 amino acids separated by shorter regions of greater variability (e.g., extreme variability) called “hypervariable regions” that are each about 9-12 amino acids long. The variable regions of heavy and light chains each comprise four FRs, largely adopting a β sheet configuration, connected by three hypervariable regions, which form loops connecting, and in some cases form part of, the β sheet structure. The hypervariable regions in each chain are held together in close proximity by the FRs and, with the hypervariable regions from the other chain, contribute to the formation of the antigen-binding site of antibodies (see, e.g., Kabat et al., Sequences of Proteins of Immunological Interest (5th ed. 1991) ) . The constant regions are not involved directly in binding an antibody to an antigen, but exhibit various effector functions, such as participation of the antibody in antibody dependent cellular cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) . The variable regions differ extensively in sequence between different antibodies. In specific embodiments, the variable region is a human variable region.

The term “variable region residue numbering according to Kabat” or “amino acid position numbering as in Kabat” , and variations thereof, refer to the numbering system used for heavy chain variable regions or light chain variable regions of the compilation of antibodies in Kabat et al., supra. Using this numbering system, the actual linear amino acid sequence may contain fewer or additional amino acids corresponding to a shortening of, or insertion into, an FR or CDR of the variable domain. For example, a heavy chain variable domain may include a single amino acid insert (residue 52a according to Kabat) after residue 52 and three inserted residues (e.g., residues 82a, 82b, and 82c, etc. according to Kabat) after residue 82. The Kabat numbering of residues may be determined for a given antibody by alignment at regions of homology of the sequence of the antibody with a “standard” Kabat numbered sequence. The Kabat numbering system is generally used when referring to a residue in the variable domain (approximately residues 1-107 of the light chain and residues 1-113 of the heavy chain) (e.g., Kabat et al., supra) . The “EU numbering system” or “EU index” is generally used when referring to a residue in an immunoglobulin heavy chain constant region (e.g., the EU index reported in Kabat et al., supra) . The “EU index as in Kabat” refers to the residue numbering of the human IgG 1 EU antibody. Other numbering systems have been described, for example, by AbM, Chothia, Contact, IMGT, and AHon.

The term “heavy chain” when used in reference to an antibody refers to a polypeptide chain of about 50-70 kDa, wherein the amino-terminal portion includes a variable region of about 120 to 130 or more amino acids, and a carboxy-terminal portion includes a constant region. The constant region can be one of five distinct types, (e.g., isotypes) referred to as alpha (α) , delta (δ) , epsilon (ε) , gamma (γ) , and mu (μ) , based on the amino acid sequence of the heavy chain constant region. The distinct heavy chains differ in size: α, δ, and γ contain approximately 450 amino acids, while μ and ε contain approximately 550 amino acids. When combined with a light chain, these distinct types of heavy chains give rise to five well known classes (e.g., isotypes) of antibodies, IgA, IgD, IgE, IgG, and IgM, respectively, including four subclasses of IgG, namely IgG1, IgG2, IgG3, and IgG4.

The term “light chain” when used in reference to an antibody refers to a polypeptide chain of about 25 kDa, wherein the amino-terminal portion includes a variable region of about 100 to about 110 or more amino acids, and a carboxy-terminal portion includes a constant region. The approximate length of a light chain is 211 to 217 amino acids. There are two distinct types, referred to as kappa (κ) or lambda (λ) based on the amino acid sequence of the constant domains.

As used herein, the terms “hypervariable region, ” “HVR, ” “Complementarity Determining Region, ” and “CDR” are used interchangeably. A “CDR” refers to one of three hypervariable regions (H1, H2 or H3) within the non-framework region of the immunoglobulin (Ig or antibody) VH β-sheet framework, or one of three hypervariable regions (L1, L2 or L3) within the non-framework region of the antibody VL β-sheet framework. Accordingly, CDRs are variable region sequences interspersed within the framework region sequences.

CDR regions are well known to those skilled in the art and have been defined by well-known numbering systems. For example, the Kabat Complementarity Determining Regions (CDRs) are based on sequence variability and are the most commonly used (see, e.g., Kabat et al., supra) . Chothia refers instead to the location of the structural loops (see, e.g., Chothia and Lesk, J. Mol. Biol. 196: 901-17 (1987) ) . The end of the Chothia CDR-H1 loop when numbered using the Kabat numbering convention varies between H32 and H34 depending on the length of the loop (this is because the Kabat numbering scheme places the insertions at H35A and H35B; if neither 35A nor 35B is present, the loop ends at 32; if only 35A is present, the loop ends at 33; if both 35A and 35B are present, the loop ends at 34) . The AbM hypervariable regions represent a compromise between the Kabat CDRs and Chothia structural loops, and are used by Oxford Molecular’s AbM antibody modeling software (see, e.g., Antibody Engineering Vol. 2 (Kontermann and Dübel eds., 2d ed. 2010) ) . The “contact” hypervariable regions are based on an analysis of the available complex crystal structures. Another universal numbering system that has been developed and widely adopted is ImMunoGeneTics (IMGT) Information

(Lafranc et al., Dev. Comp. Immunol. 27 (1) : 55-77 (2003) ) . IMGT is an integrated information system specializing in immunoglobulins (IG) , T-cell receptors (TCR) , and major histocompatibility complex (MHC) of human and other vertebrates. Herein, the CDRs are referred to in terms of both the amino acid sequence and the location within the light or heavy chain. As the “location” of the CDRs within the structure of the immunoglobulin variable domain is conserved between species and present in structures called loops, by using numbering systems that align variable domain sequences according to structural features, CDR and framework residues are readily identified. This information can be used in grafting and replacement of CDR residues from immunoglobulins of one species into an acceptor framework from, typically, a human antibody. An additional numbering system (AHon) has been developed by Honegger and Plückthun, J. Mol. Biol. 309: 657-70 (2001) . Correspondence between the numbering system, including, for example, the Kabat numbering and the IMGT unique numbering system, is well known to one skilled in the art (see, e.g., Kabat, supra; Chothia and Lesk, supra; Martin, supra; Lefranc et al., supra) . The residues from each of these hypervariable regions or CDRs are exemplified in Table 1 below.

Table 1. Exemplary CDRs According to Various Numbering Systems

The boundaries of a given CDR may vary depending on the scheme used for identification. Thus, unless otherwise specified, the terms “CDR” and “complementary determining region” of a given antibody or region thereof, such as a variable region, as well as individual CDRs (e.g., CDR-H1, CDR-H2) of the antibody or region thereof, should be understood to encompass the complementary determining region as defined by any of the known schemes described herein above. In some instances, the scheme for identification of a particular CDR or CDRs is specified, such as the CDR as defined by the IMGT, Kabat, Chothia, or Contact method. In other cases, the particular amino acid sequence of a CDR is given. It should be noted CDR regions may also be defined by a combination of various numbering systems, e.g., a combination of Kabat and Chothia numbering systems, or a combination of Kabat and IMGT numbering systems. Therefore, the term such as “a CDR as set forth in a specific VH” includes any CDR1 as defined by the exemplary CDR numbering systems described above, but is not limited thereby. Once a variable region (e.g., a VH or VL) is given, those skilled in the art would understand that CDRs within the region can be defined by different numbering systems or combinations thereof.

Hypervariable regions may comprise “extended hypervariable regions” as follows: 24-36 or 24-34 (L1) , 46-56 or 50-56 (L2) , and 89-97 or 89-96 (L3) in the VL, and 26-35 or 26-35A (H1) , 50-65 or 49-65 (H2) , and 93-102, 94-102, or 95-102 (H3) in the VH.

The term “constant region” or “constant domain” refers to a carboxy terminal portion of the light and heavy chain which is not directly involved in binding of the antibody to antigen but exhibits various effector function, such as interaction with the Fc receptor. The term refers to the portion of an immunoglobulin molecule having a more conserved amino acid sequence relative to the other portion of the immunoglobulin, the variable region, which contains the antigen binding site. The constant region may contain the CH1, CH2, and CH3 regions of the heavy chain and the CL region of the light chain.

The term “framework” or “FR” refers to those variable region residues flanking the CDRs. FR residues are present, for example, in chimeric, humanized, human, domain antibodies (e.g., single domain antibodies) , diabodies, linear antibodies, and bispecific antibodies. FR residues are those variable domain residues other than the hypervariable region residues or CDR residues.

The term “Fc region” herein is used to define a C-terminal region of an immunoglobulin heavy chain, including, for example, native sequence Fc regions, recombinant Fc regions, and variant Fc regions. Although the boundaries of the Fc region of an immunoglobulin heavy chain might vary, the human IgG heavy chain Fc region is often defined to stretch from an amino acid residue at position Cys226, or from Pro230, to the carboxyl-terminus thereof. The C-terminal lysine (residue 447 according to the EU numbering system) of the Fc region may be removed, for example, during production or purification of the antibody, or by recombinantly engineering the nucleic acid encoding a heavy chain of the antibody. Accordingly, a composition of intact antibodies may comprise antibody populations with all K447 residues removed, antibody populations with no K447 residues removed, and antibody populations having a mixture of antibodies with and without the K447 residue. A “functional Fc region” possesses an “effector function” of a native sequence Fc region. Exemplary “effector functions” include C1q binding; CDC; Fc receptor binding; ADCC; phagocytosis; downregulation of cell surface receptors (e.g., B cell receptor) , etc. Such effector functions generally require the Fc region to be combined with a binding region or binding domain (e.g., an antibody variable region or domain) and can be assessed using various assays known to those skilled in the art. A “variant Fc region” comprises an amino acid sequence which differs from that of a native sequence Fc region by virtue of at least one amino acid modification (e.g., substituting, addition, or deletion) . In certain embodiments, the variant Fc region has at least one amino acid substitution compared to a native sequence Fc region or to the Fc region of a parent polypeptide, for example, from about one to about ten amino acid substitutions, or from about one to about five amino acid substitutions in a native sequence Fc region or in the Fc region of a parent polypeptide. The variant Fc region herein can possess at least about 80%homology with a native sequence Fc region and/or with an Fc region of a parent polypeptide, or at least about 90%homology therewith, for example, at least about 95%homology therewith.

As used herein, an “epitope” is a term in the art and refers to a localized region of an antigen to which a binding molecule (e.g., an antibody comprising a single domain antibody sequence) can specifically bind. An epitope can be a linear epitope or a conformational, non-linear, or discontinuous epitope. In the case of a polypeptide antigen, for example, an epitope can be contiguous amino acids of the polypeptide (a “linear” epitope) or an epitope can comprise amino acids from two or more non-contiguous regions of the polypeptide (a “conformational, ” “non-linear” or “discontinuous” epitope) . It will be appreciated by one of skill in the art that, in general, a linear epitope may or may not be dependent on secondary, tertiary, or quaternary structure. For example, in some embodiments, a binding molecule binds to a group of amino acids regardless of whether they are folded in a natural three dimensional protein structure. In other embodiments, a binding molecule requires amino acid residues making up the epitope to exhibit a particular conformation (e.g., bend, twist, turn or fold) in order to recognize and bind the epitope.

“Percent (%) amino acid sequence identity” and “homology” with respect to a peptide, polypeptide or antibody sequence are defined as the percentage of amino acid residues in a candidate sequence that are identical with the amino acid residues in the specific peptide or polypeptide sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part of the sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN or MEGALIGN ^TM (DNASTAR) software. Those skilled in the art can determine appropriate parameters for measuring alignment, including any algorithms needed to achieve maximal alignment over the full length of the sequences being compared.

“Chimeric antigen receptor” or “CAR” as used herein refers to genetically engineered receptors, which can be used to graft one or more antigen specificity onto immune effector cells, such as T cells. Some CARs are also known as “artificial T-cell receptors, ” “chimeric T cell receptors, ” or “chimeric immune receptors. ” In some embodiments, the CAR comprises an extracellular antigen binding domain specific for one or more antigens (such as tumor antigens) , a transmembrane domain, and an intracellular signaling domain of a T cell and/or other receptors. “CAR-T cell” refers to a T cell that expresses a CAR.

The terms “polypeptide” and “peptide” and “protein” are used interchangeably herein and refer to polymers of amino acids of any length. The polymer may be linear or branched, it may comprise modified amino acids, and it may be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified naturally or by intervention; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation or modification. Also included within the definition are, for example, polypeptides containing one or more analogs of an amino acid, including but not limited to, unnatural amino acids, as well as other modifications known in the art. It is understood that, because the polypeptides of this disclosure may be based upon antibodies or other members of the immunoglobulin superfamily, in certain embodiments, a “polypeptide” can occur as a single chain or as two or more associated chains.

“Polynucleotide” or “nucleic acid, ” as used interchangeably herein, refers to polymers of nucleotides of any length and includes DNA and RNA. The nucleotides can be deoxyribonucleotides, ribonucleotides, modified nucleotides or bases, and/or their analogs, or any substrate that can be incorporated into a polymer by DNA or RNA polymerase or by a synthetic reaction. A polynucleotide may comprise modified nucleotides, such as methylated nucleotides and their analogs. “Oligonucleotide, ” as used herein, refers to short, generally single-stranded, synthetic polynucleotides that are generally, but not necessarily, fewer than about 200 nucleotides in length. The terms “oligonucleotide” and “polynucleotide” are not mutually exclusive. The description above for polynucleotides is equally and fully applicable to oligonucleotides. A cell that produces a binding molecule of the present disclosure may include a parent hybridoma cell, as well as bacterial and eukaryotic host cells into which nucleic acids encoding the antibodies have been introduced. Unless specified otherwise, the left-hand end of any single-stranded polynucleotide sequence disclosed herein is the 5’ end; the left-hand direction of double-stranded polynucleotide sequences is referred to as the 5’ direction. The direction of 5’ to 3’ addition of nascent RNA transcripts is referred to as the transcription direction; sequence regions on the DNA strand having the same sequence as the RNA transcript that are 5’ to the 5’ end of the RNA transcript are referred to as “upstream sequences” ; sequence regions on the DNA strand having the same sequence as the RNA transcript that are 3’ to the 3’ end of the RNA transcript are referred to as “downstream sequences. ”

An “isolated nucleic acid” is a nucleic acid, for example, an RNA, DNA, or mixed nucleic acids, which is substantially separated from other genome DNA sequences as well as proteins or complexes such as ribosomes and polymerases, which naturally accompany a native sequence. An “isolated” nucleic acid molecule is one which is separated from other nucleic acid molecules which are present in the natural source of the nucleic acid molecule. Moreover, an “isolated” nucleic acid molecule, such as a cDNA molecule, can be substantially free of other cellular material, or culture medium when produced by recombinant techniques, or substantially free of chemical precursors or other chemicals when chemically synthesized. In a specific embodiment, one or more nucleic acid molecules encoding a single domain antibody or an antibody as described herein are isolated or purified. The term embraces nucleic acid sequences that have been removed from their naturally occurring environment, and includes recombinant or cloned DNA isolates and chemically synthesized analogues or analogues biologically synthesized by heterologous systems. A substantially pure molecule may include isolated forms of the molecule. Specifically, an “isolated” nucleic acid molecule encoding a CAR described herein is a nucleic acid molecule that is identified and separated from at least one contaminant nucleic acid molecule with which it is ordinarily associated in the environment in which it was produced.

The term “control sequences” refers to DNA sequences necessary for the expression of an operably linked coding sequence in a particular host organism. The control sequences that are suitable for prokaryotes, for example, include a promoter, optionally an operator sequence, and a ribosome binding site. Eukaryotic cells are known to utilize promoters, polyadenylation signals, and enhancers.

As used herein, the term “operatively linked, ” and similar phrases (e.g., genetically fused) , when used in reference to nucleic acids or amino acids, refer to the operational linkage of nucleic acid sequences or amino acid sequence, respectively, placed in functional relationships with each other. For example, an operatively linked promoter, enhancer elements, open reading frame, 5' and 3' UTR, and terminator sequences result in the accurate production of a nucleic acid molecule (e.g., RNA) . In some embodiments, operatively linked nucleic acid elements result in the transcription of an open reading frame and ultimately the production of a polypeptide (i.e., expression of the open reading frame) . As another example, an operatively linked peptide is one in which the functional domains are placed with appropriate distance from each other to impart the intended function of each domain.

The term “vector” refers to a substance that is used to carry or include a nucleic acid sequence, including for example, a nucleic acid sequence encoding a binding molecule (e.g., an antibody) as described herein, in order to introduce a nucleic acid sequence into a host cell. Vectors applicable for use include, for example, expression vectors, plasmids, phage vectors, viral vectors, episomes, and artificial chromosomes, which can include selection sequences or markers operable for stable integration into a host cell’s chromosome. Additionally, the vectors can include one or more selectable marker genes and appropriate expression control sequences. Selectable marker genes that can be included, for example, provide resistance to antibiotics or toxins, complement auxotrophic deficiencies, or supply critical nutrients not in the culture media. Expression control sequences can include constitutive and inducible promoters, transcription enhancers, transcription terminators, and the like, which are well known in the art. When two or more nucleic acid molecules are to be co-expressed (e.g., both an antibody heavy and light chain or an antibody VH and VL) , both nucleic acid molecules can be inserted, for example, into a single expression vector or in separate expression vectors. For single vector expression, the encoding nucleic acids can be operationally linked to one common expression control sequence or linked to different expression control sequences, such as one inducible promoter and one constitutive promoter. The introduction of nucleic acid molecules into a host cell can be confirmed using methods well known in the art. Such methods include, for example, nucleic acid analysis such as Northern blots or polymerase chain reaction (PCR) amplification of mRNA, immunoblotting for expression of gene products, or other suitable analytical methods to test the expression of an introduced nucleic acid sequence or its corresponding gene product. It is understood by those skilled in the art that the nucleic acid molecules are expressed in a sufficient amount to produce a desired product and it is further understood that expression levels can be optimized to obtain sufficient expression using methods well known in the art.

The term “host” as used herein refers to an animal, such as a mammal (e.g., a human) .

The term “host cell” as used herein refers to a particular subject cell that may be transfected with a nucleic acid molecule and the progeny or potential progeny of such a cell. Progeny of such a cell may not be identical to the parent cell transfected with the nucleic acid molecule due to mutations or environmental influences that may occur in succeeding generations or integration of the nucleic acid molecule into the host cell genome.

As used herein, the term “autologous” is meant to refer to any material derived from the same individual to whom it is later to be re-introduced into the individual.

“Allogeneic” refers to a graft derived from a different individual of the same species.

The term “transfected” or “transformed” or “transduced” as used herein refers to a process by which exogenous nucleic acid is transferred or introduced into the host cell. A “transfected” or “transformed” or “transduced” cell is one which has been transfected, transformed or transduced with exogenous nucleic acid. The cell includes the primary subject cell and its progeny.

The term “devoid” or “devoid of” as used herein refers to substantial lack or absence of a component of interest, or substantial lack or absence of a function of a component of interest. The term “devoid” or “devoid of” as used herein include the presence of a component of interest or a structural equivalent thereof, but the function of the present component or its equivalent is substantially lacking or absent.

The term “pharmaceutically acceptable” as used herein means being approved by a regulatory agency of the Federal or a state government, or listed in United States Pharmacopeia, European Pharmacopeia, or other generally recognized Pharmacopeia for use in animals, and more particularly in humans.

“Excipient” means a pharmaceutically-acceptable material, composition, or vehicle, such as a liquid or solid filler, diluent, solvent, or encapsulating material. Excipients include, for example, encapsulating materials or additives such as absorption accelerators, antioxidants, binders, buffers, carriers, coating agents, coloring agents, diluents, disintegrating agents, emulsifiers, extenders, fillers, flavoring agents, humectants, lubricants, perfumes, preservatives, propellants, releasing agents, sterilizing agents, sweeteners, solubilizers, wetting agents and mixtures thereof. The term “excipient” can also refer to a diluent, adjuvant (e.g., Freunds’ adjuvant (complete or incomplete) or vehicle.

In some embodiments, excipients are pharmaceutically acceptable excipients. Examples of pharmaceutically acceptable excipients include buffers, such as phosphate, citrate, and other organic acids; antioxidants, including ascorbic acid; low molecular weight (e.g., fewer than about 10 amino acid residues) polypeptide; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers, such as polyvinylpyrrolidone; amino acids, such as glycine, glutamine, asparagine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates, including glucose, mannose, or dextrins; chelating agents, such as EDTA; sugar alcohols, such as mannitol or sorbitol; salt-forming counterions, such as sodium; and/or nonionic surfactants, such as TWEEN ^TM, polyethylene glycol (PEG) , and PLURONICS ^TM. Other examples of pharmaceutically acceptable excipients are described in Remington and Gennaro, Remington’s Pharmaceutical Sciences (18th ed. 1990) .

In one embodiment, each component is “pharmaceutically acceptable” in the sense of being compatible with the other ingredients of a pharmaceutical formulation, and suitable for use in contact with the tissue or organ of humans and animals without excessive toxicity, irritation, allergic response, immunogenicity, or other problems or complications, commensurate with a reasonable benefit/risk ratio. See, e.g., Lippincott Williams &Wilkins: Philadelphia, PA, 2005; Handbook of Pharmaceutical Excipients, 6th ed.; Rowe et al., Eds.; The Pharmaceutical Press and the American Pharmaceutical Association: 2009; Handbook of Pharmaceutical Additives, 3rd ed.; Ash and Ash Eds.; Gower Publishing Company: 2007; Pharmaceutical Preformulation and Formulation, 2nd ed.; Gibson Ed.; CRC Press LLC: Boca Raton, FL, 2009. In some embodiments, pharmaceutically acceptable excipients are nontoxic to the cell or mammal being exposed thereto at the dosages and concentrations employed. In some embodiments, a pharmaceutically acceptable excipient is an aqueous pH buffered solution.

In some embodiments, excipients are sterile liquids, such as water and oils, including those of petroleum, animal, vegetable, or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil, and the like. Water is an exemplary excipient when a composition (e.g., a pharmaceutical composition) is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid excipients, particularly for injectable solutions. An excipient can also include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol, and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. Compositions can take the form of solutions, suspensions, emulsion, tablets, pills, capsules, powders, sustained-release formulations, and the like. Oral compositions, including formulations, can include standard excipients such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, etc.

Compositions, including pharmaceutical compounds, may contain a binding molecule (e.g., an antibody) , for example, in isolated or purified form, together with a suitable amount of excipients.

The term “effective amount” or “therapeutically effective amount” as used herein refers to the amount of a single domain antibody or a therapeutic molecule comprising an agent and the single domain antibody or pharmaceutical composition provided herein which is sufficient to result in the desired outcome.

The terms “subject” and “patient” may be used interchangeably. As used herein, in certain embodiments, a subject is a mammal, such as a non-primate or a primate (e.g., human) . In specific embodiments, the subject is a human. In one embodiment, the subject is a mammal, e.g., a human, diagnosed with a disease or disorder. In another embodiment, the subject is a mammal, e.g., a human, at risk of developing a disease or disorder.

“Administer” or “administration” refers to the act of injecting or otherwise physically delivering a substance as it exists outside the body into a patient, such as by mucosal, intradermal, intravenous, intramuscular delivery, and/or any other method of physical delivery described herein or known in the art.

As used herein, the terms “treat, ” “treatment” and “treating” refer to the reduction or amelioration of the progression, severity, and/or duration of a disease or condition resulting from the administration of one or more therapies. Treating may be determined by assessing whether there has been a decrease, alleviation and/or mitigation of one or more symptoms associated with the underlying disorder such that an improvement is observed with the patient, despite that the patient may still be afflicted with the underlying disorder. The term “treating” includes both managing and ameliorating the disease. The terms “manage, ” “managing, ” and “management” refer to the beneficial effects that a subject derives from a therapy which does not necessarily result in a cure of the disease.

The terms “prevent, ” “preventing, ” and “prevention” refer to reducing the likelihood of the onset (or recurrence) of a disease, disorder, condition, or associated symptom (s) (e.g., diabetes or a cancer) .

As used herein, “delaying” the development of cancer means to defer, hinder, slow, retard, stabilize, and/or postpone development of the disease. This delay can be of varying lengths of time, depending on the history of the disease and/or individual being treated. As is evident to one skilled in the art, a sufficient or significant delay can, in effect, encompass prevention, in that the individual does not develop the disease. A method that "delays" development of cancer is a method that reduces probability of disease development in a given time frame and/or reduces the extent of the disease in a given time frame, when compared to not using the method. Such comparisons are typically based on clinical studies, using a statistically significant number of individuals. Cancer development can be detectable using standard methods, including, but not limited to, computerized axial tomography (CAT Scan) , Magnetic Resonance Imaging (MRI) , abdominal ultrasound, clotting tests, arteriography, or biopsy. Development may also refer to cancer progression that may be initially undetectable and includes occurrence, recurrence, and onset.

The terms “about” and “approximately” mean within 20%, within 15%, within 10%, within 9%, within 8%, within 7%, within 6%, within 5%, within 4%, within 3%, within 2%, within 1%, or less of a given value or range.

As used in the present disclosure and claims, the singular forms “a” , “an” and “the” include plural forms unless the context clearly dictates otherwise.

It is understood that wherever embodiments are described herein with the term “comprising” otherwise analogous embodiments described in terms of “consisting of” and/or “consisting essentially of” are also provided. It is also understood that wherever embodiments are described herein with the phrase “consisting essentially of” otherwise analogous embodiments described in terms of “consisting of” are also provided.

The term “between” as used in a phrase as such “between A and B” or “between A-B” refers to a range including both A and B.

The term “and/or” as used in a phrase such as “A and/or B” herein is intended to include both A and B; A or B; A (alone) ; and B (alone) . Likewise, the term “and/or” as used in a phrase such as “A, B, and/or C” is intended to encompass each of the following embodiments: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone) ; B (alone) ; and C (alone) .

5.2. Engineered Immune Cells Comprising a Chimeric Co-Stimulatory Receptor and a Chimeric Antigen Receptor

Provided herein, in one aspect, is an engineered immune cells expressing a chimeric co-stimulatory receptor comprising only a co-stimulatory domain without a primary intracellular signaling domain (such as a CD3 ζ endocellular domain) , and a chimeric antigen receptor (CAR) comprising a co-stimulatory domain as well as a primary intracellular signaling domain (such as a CD3 ζ endocellular domain) . The chimeric co-stimulatory receptor and the CAR each is capable of binding to an antigen. In some embodiments, the antigen of the chimeric co-stimulatory receptor and the antigen of the CAR are different. In some embodiments, the antigen of the chimeric co-stimulatory receptor is present on a tumor cell with relatively high level.

Thus, in some embodiments, provided herein is an immune cell (e.g., a CAR-T cell) , comprising: (a) a chimeric co-stimulatory receptor comprising (i) a first extracellular domain capable of binding to a first epitope, (ii) a first transmembrane domain, and (iii) a first intracellular domain comprising a first co-stimulatory domain devoid of a signaling domain of CD3 zeta; and (b) a CAR comprising (i) a second extracellular domain capable of binding to a second epitope, (ii) a second transmembrane domain, and (iii) a second intracellular domain comprising a signaling domain and a second co-stimulatory domain. In some embodiments, the second intracellular domain further comprises a third co-stimulatory domain. The chimeric co-stimulatory receptor may further comprises a first hinge region and the CAR may further comprises a second hinge region.

In a preferred embodiment, the first hinge region is different from the second hinge region, and/or the first transmembrane domain is different from the second transmembrane domain, to ensure proper assembly of the two receptors on immune cells.

Embodiments of the present disclosure concern methods and compositions for enhancing immune cell expansion and/or proliferation. In specific cases, T-cells express a particular co-stimulatory receptor molecule to facilitate expansion of the T-cells in vivo for use as a therapy for a medical condition, including cancer. In specific embodiments, the co-stimulatory receptor comprises at least one extracelluar domain, a hinge domain, a transmembrane domain, and an intracellular domain comprising a co-stimulatory domain but without a primary signaling domain.

In particular embodiments, the extracelluar domain is a single chain variable fragment (scFv) that bind specifically to ganglioside GD2. In specific cases, the scFv is derived from the variable heavy chain and the variable light chain of anti-GD2 antibody 14.18 joined by a glycine-serine linker. In particular embodiments, the extracelluar domain is a single chain variable fragment (scFv) that bind specifically to CD326 (EpCAM) . In particular embodiments, the extracelluar domain is a single domain antibody fragment (V _HH) that binds specifically to DLL3. In particular embodiments, the extracelluar domain is a single domain antibody fragment (V _HH) that binds specifically to MSLN. In particular embodiments, the extracelluar domain is a single chain variable fragment (scFv) that bind specifically to CD276 (B7-H3) .

In certain embodiments, the hinge domain and transmembrane domain are derived from human CD28 or CD8α molecules. In certain embodiments, the hinge domain is derived from human CD28 or a variant thereof having 1-5 amino acid modifications. In certain embodiments, the transmembrane domain is derived from human CD28 or a variant thereof having 1-5 amino acid modifications. In certain embodiments, the hinge domain is derived from human CD28 and joined with a transmembrane domain derived from ICOS or CD2 molecules. In specific aspects of this disclosure, a chimeric co-stimulatory receptor induces costimulatory molecule activity. In certain embodiment, the intracellular co-stimulatory domain is CD28 or 4-1BB or ICOS or CD2.

In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to GD2, and an intracellular domain comprising a co-stimulatory domain from CD28. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to GD2, and an intracellular domain comprising a co-stimulatory domain from 4-1BB. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to GD2, and an intracellular domain comprising a co-stimulatory domain from CD2. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to GD2, and an intracellular domain comprising a co-stimulatory domain from ICOS. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to CD326, and an intracellular domain comprising a co-stimulatory domain from CD28. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to CD326, and an intracellular domain comprising a co-stimulatory domain from 4-1BB. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to CD326, and an intracellular domain comprising a co-stimulatory domain from CD2. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to CD326, and an intracellular domain comprising a co-stimulatory domain from ICOS. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to DLL3, and an intracellular domain comprising a co-stimulatory domain from CD28. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to DLL3, and an intracellular domain comprising a co-stimulatory domain from 4-1BB. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to DLL3, and an intracellular domain comprising a co-stimulatory domain from CD2. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to DLL3, and an intracellular domain comprising a co-stimulatory domain from ICOS. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to MSLN, and an intracellular domain comprising a co-stimulatory domain from CD28. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to MSLN, and an intracellular domain comprising a co-stimulatory domain from 4-1BB. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to MSLN, and an intracellular domain comprising a co-stimulatory domain from CD2. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to MSLN, and an intracellular domain comprising a co-stimulatory domain from ICOS. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to B7-H3, and an intracellular domain comprising a co-stimulatory domain from CD28. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to B7-H3, and an intracellular domain comprising a co-stimulatory domain from 4-1BB. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to B7-H3, and an intracellular domain comprising a co-stimulatory domain from CD2. In some specific embodiments, the chimeric co-stimulatory receptor comprises an extracellular domain capable of binding to B7-H3, and an intracellular domain comprising a co-stimulatory domain from ICOS. Exemplary sequences for the present chimeric co-stimulatory receptors are provided in Section 6 below, for example, as set forth in any of SEQ ID NOs: 20 to 32 and SEQ ID NOs: 40 to 55.

In particular embodiments, a cell (s) expressing a chimeric co-stimulatory receptor is an immune cell. The cell may be a NK cell, a NK T-cell, αβ T cell, γδ T cell, innate lymphoid cell, a stem cell. In specific embodiments, the cell comprises a non-natural molecule that confer antigen specificity for the cell. The cell may further comprise at least one additional engineered receptor, for example another chimeric co-stimulatory receptor, a chimeric antigen receptor, a recombinant T-cell receptor, a bispecific T-cell engager (BiTE) , dual-affinity retargeting protein (DART) , or a combination thereof.

More detailed description of the CAR and the chimeric co-stimulatory receptor provided herein are provided in Section 5.2.1 and Section 5.2.2 below.

5.2.1. Chimeric Antigen Receptors

In some embodiments, the CAR provided herein comprises a polypeptide comprising: (a) an extracellular antigen binding domain; (b) a transmembrane domain; and (c) an intracellular signaling domain, each of which and additional regions are described in more detail below. The term chimeric antigen receptor or CAR as used in this section, i.e., Section 5.2.1, refers to a chimeric antigen receptor comprising both a primary intracellular signaling domain and at least one co-stimulatory signaling domain.

Extracellular Antigen Binding Domain

The extracellular antigen binding domain of the CARs described herein comprises one or more antigen binding domains. In some embodiments, the extracellular antigen binding domain of the CAR provided herein is mono-specific. In other embodiments, the extracellular antigen binding domain of the CAR provided herein is multispecific. In other embodiments, the extracellular antigen binding domain of the CAR provided herein is multivalent. In some embodiments, the extracellular antigen binding domain comprises two or more antigen binding domains which are fused to each other directly via peptide bonds, or via peptide linkers.

In some embodiments, the extracellular antigen binding domain comprises an antibody or a fragment thereof. For example, the binding domain may be derived from monoclonal antibodies (including agonist, antagonist, neutralizing antibodies, full length or intact monoclonal antibodies) , antibody with polyepitopic or monoepitopic specificity, polyclonal or monovalent antibodies, multivalent antibodies, multispecific antibodies (e.g., bispecific antibodies so long as they exhibit the desired biological activity) , formed from at least two intact antibodies, single chain antibodies, and fragments thereof (e.g., domain antibodies) . An antibody can be human, humanized, chimeric and/or affinity matured, as well as an antibody from other species, for example, mouse, rabbit, llama, etc. In some embodiments, the antibody include a polypeptide product of B cells within the immunoglobulin class of polypeptides that is able to bind to a specific molecular antigen and is composed of two identical pairs of polypeptide chains, wherein each pair has one heavy chain (about 50-70 kDa) and one light chain (about 25 kDa) , each amino-terminal portion of each chain includes a variable region of about 100 to about 130 or more amino acids, and each carboxy-terminal portion of each chain includes a constant region. See, e.g., Antibody Engineering (Borrebaeck ed., 2d ed. 1995) ; and Kuby, Immunology (3d ed. 1997) . Antibodies also include, but are not limited to, synthetic antibodies, recombinantly produced antibodies, single domain antibodies including from Camelidae species (e.g., llama or alpaca) or their humanized variants, intrabodies, anti-idiotypic (anti-Id) antibodies, and functional fragments (e.g., antigen-binding fragments) of any of the above, which refers to a portion of an antibody heavy or light chain polypeptide that retains some or all of the binding activity of the antibody from which the fragment was derived. Non-limiting examples of functional fragments (e.g., antigen-binding fragments) include single-chain Fvs (scFv) (e.g., including monospecific, bispecific, etc. ) , Fab fragments, F (ab’) fragments, F (ab) ₂ fragments, F (ab’) ₂ fragments, disulfide-linked Fvs (dsFv) , Fd fragments, Fv fragments, diabody, triabody, tetrabody, and minibody. In particular, antibodies provided herein include immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, for example, antigen-binding domains or molecules that contain an antigen-binding site that binds to an antigen (e.g., one or more CDRs of an antibody) . Such antibody fragments can be found in, for example, Harlow and Lane, Antibodies: A Laboratory Manual (1989) ; Mol. Biology and Biotechnology: A Comprehensive Desk Reference (Myers ed., 1995) ; Huston et al., 1993, Cell Biophysics 22: 189-224; Plückthun and Skerra, 1989, Meth. Enzymol. 178: 497-515; and Day, Advanced Immunochemistry (2d ed. 1990) . The antibodies provided herein can be of any class (e.g., IgG, IgE, IgM, IgD, and IgA) or any subclass (e.g., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2) of immunoglobulin molecule. Antibodies may be agonistic antibodies or antagonistic antibodies _. Antibodies may be neither agonistic nor antagonistic.

In a specific embodiment, the extracellular antigen binding domain of the present CARs comprise a single-chain Fv (sFv or scFv) . ScFvs are antibody fragments that comprise the VH and VL antibody domains connected into a single polypeptide chain. Preferably, the scFv polypeptide further comprises a polypeptide linker between the VH and VL domains which enables the sFv to form the desired structure for antigen binding. See Pluckthun in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Moore eds., Springer-Verlag, New York, pp. 269-315 (1994) .

In another specific embodiment, the extracellular antigen binding domain of the present CARs comprises one or more single domain antibodies (sdAbs) . The sdAbs may be of the same or different origins, and of the same or different sizes. Exemplary sdAbs include, but are not limited to, heavy chain variable domains from heavy-chain only antibodies (e.g., VHH or V _NAR) , binding molecules naturally devoid of light chains, single domains (such as V _H or V _L) derived from conventional 4-chain antibodies, humanized heavy-chain only antibodies, human single domain antibodies produced by transgenic mice or rats expressing human heavy chain segments, and engineered domains and single domain scaffolds other than those derived from antibodies. Any sdAbs known in the art or developed by the present disclosure, including the single domain antibodies described above in the present disclosure, may be used to construct the CARs described herein. The sdAbs may be derived from any species including, but not limited to mouse, rat, human, camel, llama, lamprey, fish, shark, goat, rabbit, and bovine. Single domain antibodies contemplated herein also include naturally occurring single domain antibody molecules from species other than Camelidae and sharks.

In some embodiments, the sdAb is derived from a naturally occurring single domain antigen binding molecule known as heavy chain antibody devoid of light chains (also referred herein as “heavy chain only antibodies” ) . Such single domain molecules are disclosed in WO 94/04678 and Hamers-Casterman, C. et al., Nature 363: 446-448 (1993) , for example. For clarity reasons, the variable domain derived from a heavy chain molecule naturally devoid of light chain is known herein as a VHH to distinguish it from the conventional V _H of four chain immunoglobulins. Such a VHH molecule can be derived from antibodies raised in Camelidae species, for example, camel, llama, vicuna, dromedary, alpaca and guanaco. Other species besides Camelidae may produce heavy chain molecules naturally devoid of light chain, and such VHHs are within the scope of the present disclosure. In addition, humanized versions of VHHs as well as other modifications and variants are also contemplated and within the scope of the present disclosure. In some embodiments, the sdAb is derived from a variable region of the immunoglobulin found in cartilaginous fish. For example, the sdAb can be derived from the immunoglobulin isotype known as Novel Antigen Receptor (NAR) found in the serum of shark. Methods of producing single domain molecules derived from a variable region of NAR ( "IgNARs" ) are described in WO 03/014161 and Streltsov, Protein Sci. 14: 2901-2909 (2005) .

In some embodiments, naturally occurring VHH domains against a particular antigen or target, can be obtained from (

or immune) libraries of Camelid VHH sequences. Such methods may or may not involve screening such a library using said antigen or target, or at least one part, fragment, antigenic determinant or epitope thereof using one or more screening techniques known in the field. Such libraries and techniques are for example described in WO 99/37681, WO 01/90190, WO 03/025020 and WO 03/035694. Alternatively, improved synthetic or semi-synthetic libraries derived from (

or immune) VHH libraries may be used, such as VHH libraries obtained from (

or immune) VHH libraries by techniques such as random mutagenesis and/or CDR shuffling, as for example described in WO 00/43507.

In some embodiments, the sdAb is recombinant, CDR-grafted, humanized, camelized, de-immunized and/or in vitro generated (e.g., selected by phage display) . In some embodiments, the amino acid sequence of the framework regions may be altered by “camelization” of specific amino acid residues in the framework regions. Camelization refers to the replacing or substitution of one or more amino acid residues in the amino acid sequence of a (naturally occurring) VH domain from a conventional 4-chain antibody by one or more of the amino acid residues that occur at the corresponding position (s) in a VHH domain of a heavy chain antibody. This can be performed in a manner known in the field, which will be clear to the skilled person. Such “camelizing” substitutions are preferably inserted at amino acid positions that form and/or are present at the VH-VL interface, and/or at the so-called Camelidae hallmark residues, as defined herein (see for example WO 94/04678, Davies and Riechmann FEBS Letters 339: 285-290 (1994) ; Davies and Riechmann, Protein Engineering 9 (6) : 531-537 (1996) ; Riechmann, J. Mol. Biol. 259: 957-969 (1996) ; and Riechmann and Muyldermans, J. Immunol. Meth. 231: 25-38 (1999) ) .

In some embodiments, the sdAb is a human single domain antibody produced by transgenic mice or rats expressing human heavy chain segments. See, e.g., US20090307787, U.S. Pat. No. 8,754,287, US20150289489, US20100122358, and WO2004049794.

In some embodiments, the single domain antibodies are generated from conventional four-chain antibodies. See, for example, EP 0 368 684; Ward et al., Nature, 341 (6242) : 544-6 (1989) ; Holt et al., Trends Biotechnol., 21 (11) : 484-490 (2003) ; WO 06/030220; and WO 06/003388.

In some embodiments, the extracellular antigen binding domain comprises humanized antibodies or fragment thereof. A humanized antibody can comprise human framework region and human constant region sequences. Humanized antibodies can be produced using a variety of techniques known in the art, including but not limited to, CDR-grafting (European Patent No. EP 239,400; International publication No. WO 91/09967; and U.S. Patent Nos. 5,225,539, 5,530,101, and 5,585,089) , veneering or resurfacing (European Patent Nos. EP 592,106 and EP 519,596; Padlan, 1991, Molecular Immunology 28 (4/5) : 489-498; Studnicka et al., 1994, Protein Engineering 7 (6) : 805-814; and Roguska et al., 1994, PNAS 91: 969-973) , chain shuffling (U.S. Patent No. 5,565,332) , and techniques disclosed in, e.g., U.S. Pat. No. 6,407,213, U.S. Pat. No. 5,766,886, WO 93/17105, Tan et al., J. Immunol. 169: 1119 25 (2002) , Caldas et al., Protein Eng. 13 (5) : 353-60 (2000) , Morea et al., Methods 20 (3) : 267 79 (2000) , Baca et al., J. Biol. Chem. 272 (16) : 10678-84 (1997) , Roguska et al., Protein Eng. 9 (10) : 895 904 (1996) , Couto et al., Cancer Res. 55 (23 Supp) : 5973s-5977s (1995) , Couto et al., Cancer Res. 55 (8) : 1717-22 (1995) , Sandhu JS, Gene 150 (2) : 409-10 (1994) , and Pedersen et al., J. Mol. Biol. 235 (3) : 959-73 (1994) . See also U.S. Patent Pub. No. US 2005/0042664 A1 (Feb. 24, 2005) , each of which is incorporated by reference herein in its entirety.

In certain embodiments, the extracellular antigen binding domain comprises multiple binding domains. In some embodiments, the extracellular antigen binding domain comprises multispecific antibodies or fragments thereof. In other embodiments, the extracellular antigen binding domain comprises multivalent antibodies or fragments thereof. The term “specificity” refers to selective recognition of an antigen binding protein for a particular epitope of an antigen. The term "multispecific" as used herein denotes that an antigen binding protein has two or more antigen-binding sites of which at least two bind different antigens. The term “valent” as used herein denotes the presence of a specified number of binding sites in an antigen binding protein. A full length antibody has two binding sites and is bivalent. As such, the terms "trivalent" , "tetravalent" , "pentavalent" and "hexavalent" denote the presence of two binding site, three binding sites, four binding sites, five binding sites, and six binding sites, respectively, in an antigen binding protein.

Multispecific antibodies such as bispecific antibodies are antibodies that have binding specificities for at least two different antigens. Methods for making multipecific antibodies are known in the art, such as, by co-expression of two immunoglobulin heavy chain-light chain pairs, where the two heavy chains have different specificities (see, e.g., Milstein and Cuello, 1983, Nature 305: 537-40) . For further details of generating multispecific antibodies (e.g., bispecific antibodies) , see, for example, Bispecific Antibodies (Kontermann ed., 2011) .

The antibodies of the present disclosure can be multivalent antibodies with two or more antigen binding sites (e.g., tetravalent antibodies) , which can be readily produced by recombinant expression of nucleic acid encoding the polypeptide chains of the antibody. In certain embodiments, a multivalent antibody comprises (or consists of) three to about eight antigen binding sites. In one such embodiment, a multivalent antibody comprises (or consists of) four antigen binding sites. The multivalent antibody comprises at least one polypeptide chain (e.g., two polypeptide chains) , wherein the polypeptide chain (s) comprise two or more variable domains. For instance, the polypeptide chain (s) may comprise VD1- (X1) n-VD2- (X2) n-Fc, wherein VD1 is a first variable domain, VD2 is a second variable domain, Fc is one polypeptide chain of an Fc region, X1 and X2 represent an amino acid or polypeptide, and n is 0 or 1. For instance, the polypeptide chain (s) may comprise: VH-CH1-flexible linker-VH-CH1-Fc region chain; or VH-CH1-VH-CH1-Fc region chain. The multivalent antibody herein may further comprise at least two (e.g., four) light chain variable domain polypeptides. The multivalent antibody herein may, for instance, comprise from about two to about eight light chain variable domain polypeptides. The light chain variable domain polypeptides contemplated here comprise a light chain variable domain and, optionally, further comprise a CL domain.

In case there are multiple binding domains in the extracellular antigen binding domain of the present CARs, e.g., an extracellular antigen binding domain comprising multiple binding domains (e.g., multiple VHHs) in tandem. The various domains may be fused to each other via peptide linkers. In some embodiments, the domains are directly fused to each other without any peptide linkers. The peptide linkers may be the same or different. Each peptide linker may have the same or different length and/or sequence depending on the structural and/or functional features of the various domains. Each peptide linker may be selected and optimized independently. The length, the degree of flexibility and/or other properties of the peptide linker (s) used in the CARs may have some influence on properties, including but not limited to the affinity, specificity or avidity for one or more particular antigens or epitopes. In some embodiment, a peptide linker comprises flexible residues (such as glycine and serine) so that the adjacent domains are free to move relative to each other. For example, a glycine-serine doublet can be a suitable peptide linker.

The peptide linker may have a naturally occurring sequence, or a non-naturally occurring sequence. For example, a sequence derived from the hinge region of heavy chain only antibodies may be used as the linker. See, for example, WO1996/34103. In some embodiments, the peptide linker is a flexible linker. Exemplary flexible linkers include but not limited to glycine polymers (G) _n, glycine-serine polymers (including, for example, (GS) _n, (GSGGS) _n (SEQ ID NO: 56) , (GGGS) _n (SEQ ID NO: 57) , and (GGGGS) _n (SEQ ID NO: 58) , where n is an integer of at least one) , glycine-alanine polymers, alanine-serine polymers, and other flexible linkers known in the art. Exemplary peptide linkers are listed in the table below. Other linkers known in the art, for example, as described in WO2016014789, WO2015158671, WO2016102965, US20150299317, WO2018067992, US7741465, Colcher et al., J. Nat. Cancer Inst. 82: 1191-1197 (1990) , and Bird et al., Science 242: 423-426 (1988) may also be included in the CARs provided herein, the disclosure of each of which is incorporated herein by reference.

In some embodiments, the extracellular antigen binding domain provided in the present CARs recognizes an antigen that acts as a cell surface marker on target cells associated with a special disease state. In some embodiments, the antigen is a tumor antigen. Tumors express a number of proteins that can serve as a target antigen for an immune response, particularly T cell mediated immune responses. The antigens targeted by the CAR may be antigens on a single diseased cell or antigens that are expressed on different cells that each contribute to the disease. The antigens targeted by the CAR may be directly or indirectly involved in the diseases.

Tumor antigens are proteins that are produced by tumor cells that can elicit an immune response, particularly T-cell mediated immune responses. Exemplary tumor antigens include, but not limited to, a glioma-associated antigen, carcinoembryonic antigen (CEA) , β-human chorionic gonadotropin, alphafetoprotein (AFP) , lectin-reactive AFP, thyroglobulin, RAGE-1, MN-CAIX, human telomerase reverse transcriptase, RU1, RU2 (AS) , intestinal carboxyl esterase, mut hsp70-2, M-CSF, prostase, prostate-specific antigen (PSA) , PAP, NY-ESO-1, LAGE-la, p53, prostein, PSMA, HER2/neu, survivin and telomerase, prostate-carcinoma tumor antigen-1 (PCTA-1) , MAGE, ELF2M, neutrophil elastase, ephrinB2, insulin growth factor (IGF) -I, IGF-II, IGF-I receptor, and mesothelin.

In some embodiments, the tumor antigen comprises one or more antigenic cancer epitopes associated with a malignant tumor. Malignant tumors express a number of proteins that can serve as target antigens for an immune attack. These molecules include, but are not limited to, tissue-specific antigens such as MART-1, tyrosinase and gp100 in melanoma and prostatic acid phosphatase (PAP) and prostate-specific antigen (PSA) in prostate cancer. Other target molecules belong to the group of transformation-related molecules such as the oncogene HER2/Neu/ErbB-2. Yet another group of target antigens is onco-fetal antigens such as carcinoembryonic antigen (CEA) .

In some embodiments, the tumor antigen is a tumor-specific antigen (TSA) or a tumor-associated antigen (TAA) . A TSA is unique to tumor cells and does not occur on other cells in the body. A TAA associated antigen is not unique to a tumor cell, and instead is also expressed on a normal cell under conditions that fail to induce a state of immunologic tolerance to the antigen. The expression of the antigen on the tumor may occur under conditions that enable the immune system to respond to the antigen. TAAs may be antigens that are expressed on normal cells during fetal development, when the immune system is immature, and unable to respond or they may be antigens that are normally present at extremely low levels on normal cells, but which are expressed at much higher levels on tumor cells.

Non-limiting examples of TSA or TAA antigens include: differentiation antigens such as MART-1/MelanA (MART-I) , gp 100 (Pmel 17) , tyrosinase, TRP-1, TRP-2 and tumor-specific multilineage antigens such as MAGE-1, MAGE-3, BAGE, GAGE-1, GAGE-2, pl5; overexpressed embryonic antigens such as CEA; overexpressed oncogenes and mutated tumor-suppressor genes such as p53, Ras, HER2/neu; unique tumor antigens resulting from chromosomal translocations; such as BCR-ABL, E2A-PRL, H4-RET, IGH-IGK, MYL-RAR; and viral antigens, such as the Epstein Barr virus antigens EBVA and the human papillomavirus (HPV) antigens E6 and E7.

Other large, protein-based antigens include TSP-180, MAGE-4, MAGE-5, MAGE-6, RAGE, NY-ESO, pl85erbB2, pl80erbB-3, c-met, nm-23HI, PSA, TAG-72, CA 19-9, CA 72-4, CAM 17.1, NuMa, K-ras, beta-Catenin, CDK4, Mum-1, p 15, p 16, 43-9F, 5T4, 791Tgp72, alpha-fetoprotein, beta-HCG, BCA225, BTAA, CA 125, CA 15-3\CA 27.29\BCAA, CA 195, CA 242, CA-50, CAM43, CD68\P1, CO-029, FGF-5, G250, Ga733\EpCAM, HTgp-175, M344, MA-50, MG7-Ag, MOV18, NB/70K, NY-CO-1, RCAS 1, SDCCAG16, TA-90\Mac-2 binding protein\cyclophilin C-associated protein, TAAL6, TAG72, TLP, and TPS.

Additional non-limiting exemplary targets of the CARs provided herein include GPC2, CD276, Delta-like protein ligand 3 (DLL3) , NY-ESO-1, melanoma associated antigen 4, survivin protein, synovial sarcoma X breakpoint protein 2, CD3, epidermal growth factor receptor (EGFR) , erbb2 tyrosine kinase receptor, HER2, CEA, CD66, CD66e, ROR1, ntrkr1 tyrosine kinase receptor, GPC3, mesothelin, glutamate carboxypeptidase II, PMSA, PD-L1, folate receptor alpha, PSCA, Mucin 1, HLA antigen (such as HLA class I antigen A-2 alpha, HLA class I antigen A-11 alpha, and HLA class II antigen) , c-Met, hepatocyte growth factor receptor, K-Ras GTPase (KRAS) , IL-15 receptor, Kit tyrosine kinase, PDGF receptor beta, RET tyrosine kinase receptor; Raf 1 protein kinase, Raf B protein kinase, thymidylate synthase, topoisomerase II, Brachyury protein, Flt3 tyrosine kinase, VEGF, VEGF receptor (VEGF-1 receptor, VEGF-2 receptor, and VEGF-3 receptor) , estrogen receptor, neoantigen, human papillomavirus E6, and heat shock protein.

In some specific embodiments, at least one target antigen of the present CARs is CD19. In other specific embodiments, at least one target antigen of the present CARs is CD20. In yet other specific embodiments, at least one target antigen of the present CARs is CD22. In yet other specific embodiments, at least one target antigen of the present CARs is BCMA. In yet other specific embodiments, at least one target antigen of the present CARs is VEGFR2. In yet other specific embodiments, at least one target antigen of the present CARs is FAP. In yet other specific embodiments, at least one target antigen of the present CARs is EpCam. In yet other specific embodiments, at least one target antigen of the present CARs is GPC3. In yet other specific embodiments, at least one target antigen of the present CARs is CD133. In yet other specific embodiments, at least one target antigen of the present CARs is IL13Ra. In yet other specific embodiments, at least one target antigen of the present CARs is EGFRIII. In yet other specific embodiments, at least one target antigen of the present CARs is EphA2. In yet other specific embodiments, at least one target antigen of the present CARs is Muc1. In yet other specific embodiments, at least one target antigen of the present CARs is CD70. In yet other specific embodiments, at least one target antigen of the present CARs is CD123. In yet other specific embodiments, at least one target antigen of the present CARs is ROR1. In yet other specific embodiments, at least one target antigen of the present CARs is PSMA. In yet other specific embodiments, at least one target antigen of the present CARs is CD5. In yet other specific embodiments, at least one target antigen of the present CARs is GD2. In yet other specific embodiments, at least one target antigen of the present CARs is GAP. In yet other specific embodiments, at least one target antigen of the present CARs is CD33. In yet other specific embodiments, at least one target antigen of the present CARs is CEA. In yet other specific embodiments, at least one target antigen of the present CARs is PSCA. In yet other specific embodiments, at least one target antigen of the present CARs is Her2. In yet other specific embodiments, at least one target antigen of the present CARs is Mesothelin.

Transmembrane Domain

The CARs of the present disclosure comprise a transmembrane domain that can be directly or indirectly fused to the extracellular antigen binding domain. The transmembrane domain may be derived either from a natural or from a synthetic source. As used herein, a “transmembrane domain” refers to any protein structure that is thermodynamically stable in a cell membrane, preferably a eukaryotic cell membrane. Transmembrane domains compatible for use in the CARs described herein may be obtained from a naturally occurring protein. Alternatively, it can be a synthetic, non-naturally occurring protein segment, e.g., a hydrophobic protein segment that is thermodynamically stable in a cell membrane.

Transmembrane domains are classified based on the three dimensional structure of the transmembrane domain. For example, transmembrane domains may form an alpha helix, a complex of more than one alpha helix, a beta-barrel, or any other stable structure capable of spanning the phospholipid bilayer of a cell. Furthermore, transmembrane domains may also or alternatively be classified based on the transmembrane domain topology, including the number of passes that the transmembrane domain makes across the membrane and the orientation of the protein. For example, single-pass membrane proteins cross the cell membrane once, and multi-pass membrane proteins cross the cell membrane at least twice (e.g., 2, 3, 4, 5, 6, 7 or more times) . Membrane proteins may be defined as Type I, Type II or Type III depending upon the topology of their termini and membrane-passing segment (s) relative to the inside and outside of the cell. Type I membrane proteins have a single membrane-spanning region and are oriented such that the N-terminus of the protein is present on the extracellular side of the lipid bilayer of the cell and the C-terminus of the protein is present on the cytoplasmic side. Type II membrane proteins also have a single membrane-spanning region but are oriented such that the C-terminus of the protein is present on the extracellular side of the lipid bilayer of the cell and the N-terminus of the protein is present on the cytoplasmic side. Type III membrane proteins have multiple membrane-spanning segments and may be further sub-classified based on the number of transmembrane segments and the location of N-and C-termini.

In some embodiments, the transmembrane domain of the CAR described herein is derived from a Type I single-pass membrane protein. In some embodiments, transmembrane domains from multi-pass membrane proteins may also be compatible for use in the CARs described herein. Multi-pass membrane proteins may comprise a complex (at least 2, 3, 4, 5, 6, 7 or more) alpha helices or a beta sheet structure. In some embodiments, the N-terminus and the C-terminus of a multi-pass membrane protein are present on opposing sides of the lipid bilayer, e.g., the N-terminus of the protein is present on the cytoplasmic side of the lipid bilayer and the C-terminus of the protein is present on the extracellular side.

Transmembrane domains for use in the CARs described herein can also comprise at least a portion of a synthetic, non-naturally occurring protein segment. In some embodiments, the transmembrane domain is a synthetic, non-naturally occurring alpha helix or beta sheet. In some embodiments, the protein segment is at least approximately 20 amino acids, e.g., at least 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or more amino acids. Examples of synthetic transmembrane domains are known in the art, for example in U.S. Patent No. 7,052,906 and PCT Publication No. WO 2000/032776, the relevant disclosures of which are incorporated by reference herein.

The transmembrane domain provided herein may comprise a transmembrane region and a cytoplasmic region located at the C-terminal side of the transmembrane domain. The cytoplasmic region of the transmembrane domain may comprise three or more amino acids and, in some embodiments, helps to orient the transmembrane domain in the lipid bilayer. In some embodiments, one or more cysteine residues are present in the transmembrane region of the transmembrane domain. In some embodiments, one or more cysteine residues are present in the cytoplasmic region of the transmembrane domain. In some embodiments, the cytoplasmic region of the transmembrane domain comprises positively charged amino acids. In some embodiments, the cytoplasmic region of the transmembrane domain comprises the amino acids arginine, serine, and lysine.

In some embodiments, the transmembrane region of the transmembrane domain comprises hydrophobic amino acid residues. In some embodiments, the transmembrane domain of the CAR provided herein comprises an artificial hydrophobic sequence. For example, a triplet of phenylalanine, tryptophan and valine may be present at the C terminus of the transmembrane domain. In some embodiments, the transmembrane region comprises mostly hydrophobic amino acid residues, such as alanine, leucine, isoleucine, methionine, phenylalanine, tryptophan, or valine. In some embodiments, the transmembrane region is hydrophobic. In some embodiments, the transmembrane region comprises a poly-leucine-alanine sequence. The hydropathy, or hydrophobic or hydrophilic characteristics of a protein or protein segment, can be assessed by any method known in the art, for example the Kyte and Doolittle hydropathy analysis.

In some embodiments, the transmembrane domain of the CAR comprises a transmembrane domain chosen from the transmembrane domain of an alpha, beta or zeta chain of a T-cell receptor, CD28, CD3 epsilon, CD45, CD4, CD5, CD8, CD9, CD16, CD22, CD33, CD37, CD64, CD80, CD86, CD134, CD137, CD154, KIRDS2, OX40, CD2, CD27, LFA-1 (CDl la, CD18) , ICOS (CD278) , 4-1BB (CD137) , GITR, CD40, BAFFR, HVEM (LIGHTR) , SLAMF7, NKp80 (KLRFl) , CD160, CD19, IL-2R beta, IL-2R gamma, IL-7R a, ITGA1, VLA1, CD49a, ITGA4, IA4, CD49D, ITGA6, VLA-6, CD49f, ITGAD, CDl ld, ITGAE, CD103, ITGAL, CDl la, LFA-1, ITGAM, CDl lb, ITGAX, CDl lc, ITGB1, CD29, ITGB2, CD18, LFA-1, ITGB7, TNFR2, DNAM1 (CD226) , SLAMF4 (CD244, 2B4) , CD84, CD96 (Tactile) , CEACAM1, CRT AM, Ly9 (CD229) , CD160 (BY55) , PSGL1, CDIOO (SEMA4D) , SLAMF6 (NTB-A, Lyl08) , SLAM (SLAMF1, CD150, IPO-3) , BLAME (SLAMF8) , SELPLG (CD162) , LTBR, PAG/Cbp, NKp44, NKp30, NKp46, NKG2D, and/or NKG2C.

In some specific embodiments, the transmembrane domain is derived from CD8α. In some embodiments, the transmembrane domain is a transmembrane domain of CD8α comprising the amino acid sequence of SEQ ID NO: 5. In other specific embodiments, the transmembrane domain is derived from CD28α. In some embodiments, the transmembrane domain is a transmembrane domain of CD28α comprising the amino acid sequence of SEQ ID NO: 6. In some embodiments, the transmembrane domain is a transmembrane domain of CD28α variant comprising the amino acid sequence of SEQ ID NO: 35.

Intracellular Signaling Domain (Primary Signaling Domain)

The intracellular signaling domain in the CARs provided herein is responsible for activation of at least one of the normal effector functions of the immune effector cell expressing the CARs. The term “effector function” refers to a specialized function of a cell. Effector function of a T cell, for example, may be cytolytic activity or helper activity including the secretion of cytokines. Thus the term “cytoplasmic signaling domain” refers to the portion of a protein which transduces the effector function signal and directs the cell to perform a specialized function. While usually the entire cytoplasmic signaling domain can be employed, in many cases it is not necessary to use the entire chain. To the extent that a truncated portion of the cytoplasmic signaling domain is used, such truncated portion may be used in place of the intact chain as long as it transduces the effector function signal. The term cytoplasmic signaling domain is thus meant to include any truncated portion of the cytoplasmic signaling domain sufficient to transduce the effector function signal.

In some embodiments, the intracellular signaling domain comprises a primary intracellular signaling domain of an immune effector cell. In some embodiments, the CAR comprises an intracellular signaling domain consisting essentially of a primary intracellular signaling domain of an immune effector cell. “Primary intracellular signaling domain” refers to cytoplasmic signaling sequence that acts in a stimulatory manner to induce immune effector functions. In some embodiments, the primary intracellular signaling domain contains a signaling motif known as immunoreceptor tyrosine-based activation motif, or ITAM. An “ITAM, ” as used herein, is a conserved protein motif that is generally present in the tail portion of signaling molecules expressed in many immune cells. The motif may comprises two repeats of the amino acid sequence YxxL/I separated by 6-8 amino acids, wherein each x is independently any amino acid, producing the conserved motif YxxL/Ix (6-8) YxxL/I. ITAMs within signaling molecules are important for signal transduction within the cell, which is mediated at least in part by phosphorylation of tyrosine residues in the ITAM following activation of the signaling molecule. ITAMs may also function as docking sites for other proteins involved in signaling pathways. Exemplary ITAM-containing primary cytoplasmic signaling sequences include those derived from CD3z, FcR gamma (FCER1G) , FcR beta (Fc Epsilon Rib) , CD3 gamma, CD3 delta, CD3 epsilon, CD5, CD22, CD79a, CD79b, and CD66d.

Co-stimulatory Signaling Domain (Co-stimulatory Domain)

The CAR provided herein comprises at least one co-stimulatory signaling domain. The term “co-stimulatory signaling domain, ” as used herein, refers to at least a portion of a protein that mediates signal transduction within a cell to induce an immune response such as an effector function. Many immune effector cells require co-stimulation, in addition to stimulation of an antigen-specific signal, to promote cell proliferation, differentiation and survival, as well as to activate effector functions of the cell.

The co-stimulatory signaling domain of the chimeric receptor described herein can be a cytoplasmic signaling domain from a co-stimulatory protein, which transduces a signal and modulates responses mediated by immune cells, such as T cells, NK cells, macrophages, neutrophils, or eosinophils. “Co-stimulatory signaling domain” can be the cytoplasmic portion of a co-stimulatory molecule. The term "co-stimulatory molecule" refers to a cognate binding partner on an immune cell (such as T cell) that specifically binds with a co-stimulatory ligand, thereby mediating a co-stimulatory response by the immune cell, such as, but not limited to, proliferation and survival.

In some embodiments, the intracellular signaling domain comprises a single co-stimulatory signaling domain. In some embodiments, the intracellular signaling domain comprises two or more (such as about any of 2, 3, 4, or more) co-stimulatory signaling domains. In some embodiments, the intracellular signaling domain comprises two or more of the same co-stimulatory signaling domains. In some embodiments, the intracellular signaling domain comprises two or more co-stimulatory signaling domains from different co-stimulatory proteins, such as any two or more co-stimulatory proteins described herein. In some embodiments, the intracellular signaling domain comprises a primary intracellular signaling domain (such as cytoplasmic signaling domain of CD3z) and one or more co-stimulatory signaling domains. In some embodiments, the one or more co-stimulatory signaling domains and the primary intracellular signaling domain (such as cytoplasmic signaling domain of CD3z) are fused to each other via optional peptide linkers. The primary intracellular signaling domain, and the one or more co-stimulatory signaling domains may be arranged in any suitable order. In some embodiments, the one or more co-stimulatory signaling domains are located between the transmembrane domain and the primary intracellular signaling domain (such as cytoplasmic signaling domain of CD3z) . Multiple co-stimulatory signaling domains may provide additive or synergistic stimulatory effects.

Activation of a co-stimulatory signaling domain in a host cell (e.g., an immune cell) may induce the cell to increase or decrease the production and secretion of cytokines, phagocytic properties, proliferation, differentiation, survival, and/or cytotoxicity. The co-stimulatory signaling domain of any co-stimulatory molecule may be compatible for use in the CARs described herein. The type (s) of co-stimulatory signaling domain is selected based on factors such as the type of the immune effector cells in which the effector molecules would be expressed (e.g., T cells, NK cells, macrophages, neutrophils, or eosinophils) and the desired immune effector function (e.g., ADCC effect) . Examples of co-stimulatory signaling domains for use in the CARs can be the cytoplasmic signaling domain of co-stimulatory proteins, including, without limitation, members of the B7/CD28 family (e.g., B7-1/CD80, B7-2/CD86, B7-H1/PD-L1, B7-H2, B7-H3, B7-H4, B7-H6, B7-H7, BTLA/CD272, CD28, CTLA-4, Gi24/VISTA/B7-H5, ICOS/CD278, PD-1, PD-L2/B7-DC, and PDCD6) ; members of the TNF superfamily (e.g., 4-1BB/TNFSF9/CD137, 4-1BB Ligand/TNFSF9, BAFF/BLyS/TNFSF13B, BAFF R/TNFRSF13C, CD27/TNFRSF7, CD27 Ligand/TNFSF7, CD30/TNFRSF8, CD30 Ligand/TNFSF8, CD40/TNFRSF5, CD40/TNFSF5, CD40 Ligand/TNFSF5, DR3/TNFRSF25, GITR/TNFRSF18, GITR Ligand/TNFSF18, HVEM/TNFRSF14, LIGHT/TNFSF14, Lymphotoxin-alpha/TNF-beta, OX40/TNFRSF4, OX40 Ligand/TNFSF4, RELT/TNFRSF19L, TACI/TNFRSF13B, TL1A/TNFSF15, TNF-alpha, and TNF RII/TNFRSF1B) ; members of the SLAM family (e.g., 2B4/CD244/SLAMF4, BLAME/SLAMF8, CD2, CD2F-10/SLAMF9, CD48/SLAMF2, CD58/LFA-3, CD84/SLAMF5, CD229/SLAMF3, CRACC/SLAMF7, NTB-A/SLAMF6, and SLAM/CD150) ; and any other co-stimulatory molecules, such as CD2, CD7, CD53, CD82/Kai-1, CD90/Thy1, CD96, CD160, CD200, CD300a/LMIR1, HLA Class I, HLA-DR, Ikaros, Integrin alpha 4/CD49d, Integrin alpha 4 beta 1, Integrin alpha 4 beta 7/LPAM-1, LAG-3, TCL1A, TCL1B, CRTAM, DAP12, Dectin-1/CLEC7A, DPPIV/CD26, EphB6, TIM-1/KIM-1/HAVCR, TIM-4, TSLP, TSLP R, lymphocyte function associated antigen-1 (LFA-1) , and NKG2C. In some embodiments, the one or more co-stimulatory signaling domains are selected from the group consisting of CD27, CD28, CD137, OX40, CD30, CD40, CD3, lymphocyte function-associated antigen-1 (LFA-1) , CD2, CD7, LIGHT, NKG2C, B7-H3 and ligands that specially bind to CD83.

In some embodiments, the co-stimulatory signaling domains are variants of any of the co-stimulatory signaling domains described herein, such that the co-stimulatory signaling domain is capable of modulating the immune response of the immune cell. In some embodiments, the co-stimulatory signaling domains comprises up to 10 amino acid residue variations (e.g., 1, 2, 3, 4, 5, or 8) as compared to a wild-type counterpart. Such co-stimulatory signaling domains comprising one or more amino acid variations may be referred to as variants. Mutation of amino acid residues of the co-stimulatory signaling domain may result in an increase in signaling transduction and enhanced stimulation of immune responses relative to co-stimulatory signaling domains that do not comprise the mutation. Mutation of amino acid residues of the co-stimulatory signaling domain may result in a decrease in signaling transduction and reduced stimulation of immune responses relative to co-stimulatory signaling domains that do not comprise the mutation.

Signal Peptide

In certain embodiments, the CARs provided herein may comprise a signal peptide (also known as a signal sequence) at the N-terminus of the polypeptide. In general, signal peptides are peptide sequences that target a polypeptide to the desired site in a cell. In some embodiments, the signal peptide targets the effector molecule to the secretory pathway of the cell and will allow for integration and anchoring of the effector molecule into the lipid bilayer. Signal peptides including signal sequences of naturally occurring proteins or synthetic, non-naturally occurring signal sequences, which are compatible for use in the CARs described herein will be evident to one of skill in the art. In some embodiments, the signal peptide is derived from a molecule selected from the group consisting of CD8α, GM-CSF receptor α, and IgG1 heavy chain. In a specific embodiment, the signal peptide comprises an amino acid sequence of SEQ ID NO: 2.

Hinge Region

In some embodiments, the CARs provided herein comprise a hinge domain that is located between the extracellular antigen binding domain and the transmembrane domain. A hinge domain is an amino acid segment that is generally found between two domains of a protein and may allow for flexibility of the protein and movement of one or both of the domains relative to one another. Any amino acid sequence that provides such flexibility and movement of the extracellular antigen binding domain relative to the transmembrane domain of the effector molecule can be used.

Hinge domains of antibodies, such as an IgG, IgA, IgM, IgE, or IgD antibodies, are also compatible for use in the pH-dependent chimeric receptor systems described herein. In some embodiments, the hinge domain is the hinge domain that joins the constant domains CH1 and CH2 of an antibody. In some embodiments, the hinge domain is of an antibody and comprises the hinge domain of the antibody and one or more constant regions of the antibody. In some embodiments, the hinge domain comprises the hinge domain of an antibody and the CH3 constant region of the antibody. In some embodiments, the hinge domain comprises the hinge domain of an antibody and the CH2 and CH3 constant regions of the antibody. In some embodiments, the antibody is an IgG, IgA, IgM, IgE, or IgD antibody. In some embodiments, the antibody is an IgG antibody. In some embodiments, the antibody is an IgG1, IgG2, IgG3, or IgG4 antibody. In some embodiments, the hinge region comprises the hinge region and the CH2 and CH3 constant regions of an IgG1 antibody. In some embodiments, the hinge region comprises the hinge region and the CH3 constant region of an IgG1 antibody.

Non-naturally occurring peptides may also be used as hinge domains for the chimeric receptors described herein. In some embodiments, the hinge domain between the C-terminus of the extracellular ligand-binding domain of an Fc receptor and the N-terminus of the transmembrane domain is a peptide linker, such as a (GxS) n linker, wherein x and n, independently can be an integer between 3 and 12, including 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or more.

The hinge domain may contain about 10-100 amino acids, e.g., about any one of 15-75 amino acids, 20-50 amino acids, or 30-60 amino acids. In some embodiments, the hinge domain may be at least about any one of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60, 65, 70, or 75 amino acids in length.

In some embodiments, the hinge domain is a hinge domain of a naturally occurring protein. Hinge domains of any protein known in the art to comprise a hinge domain are compatible for use in the chimeric receptors described herein. In some embodiments, the hinge domain is at least a portion of a hinge domain of a naturally occurring protein and confers flexibility to the chimeric receptor.

In some specific embodiments, the hinge domain is derived from CD8α. In some embodiments, the hinge domain is a portion of the hinge domain of CD8α, e.g., a fragment containing at least 15 (e.g., 20, 25, 30, 35, or 40) consecutive amino acids of the hinge domain of CD8α. In some embodiments, the hinge domain of CD8α comprises the amino acid sequence of SEQ ID NO: 3. In other embodiments, the hinge domain is derived from CD28α. In some embodiments, the hinge domain is a portion of the hinge domain of CD28α, e.g., a fragment containing at least 15 (e.g., 20, 25, 30, 35, or 40) consecutive amino acids of the hinge domain of CD28α. In some embodiments, the hinge domain of CD28α comprises the amino acid sequence of SEQ ID NO: 4. In some embodiments, the hinge domain of CD28α variant comprises the amino acid sequence of SEQ ID NO: 34.

Exemplary CARs

Any CARs can be used in the present disclosure.

In certain embodiments, the CAR provided herein comprises amino acid sequences with certain percent identity relative to any one of the CARs exemplified in Section 6 below. In some embodiments, provided herein is a CAR comprising or consisting of an extracellular domain having at least 75%, 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%sequence identity to the amino acid sequence of the CARs exemplified in Section 6 below.

The determination of percent identity between two sequences (e.g., amino acid sequences or nucleic acid sequences) can be accomplished using a mathematical algorithm. A preferred, non-limiting example of a mathematical algorithm utilized for the comparison of two sequences is the algorithm of Karlin and Altschul, Proc. Natl. Acad. Sci. U.S.A. 87: 2264 2268 (1990) , modified as in Karlin and Altschul, Proc. Natl. Acad. Sci. U.S.A. 90: 5873 5877 (1993) . Such an algorithm is incorporated into the NBLAST and XBLAST programs of Altschul et al., J. Mol. Biol. 215: 403 (1990) . BLAST nucleotide searches can be performed with the NBLAST nucleotide program parameters set, e.g., for score=100, word length=12 to obtain nucleotide sequences homologous to a nucleic acid molecules described herein. BLAST protein searches can be performed with the XBLAST program parameters set, e.g., to score 50, word length=3 to obtain amino acid sequences homologous to a protein molecule described herein. To obtain gapped alignments for comparison purposes, Gapped BLAST can be utilized as described in Altschul et al., Nucleic Acids Res. 25: 3389 3402 (1997) . Alternatively, PSI BLAST can be used to perform an iterated search which detects distant relationships between molecules (Id. ) . When utilizing BLAST, Gapped BLAST, and PSI Blast programs, the default parameters of the respective programs (e.g., of XBLAST and NBLAST) can be used (see, e.g., National Center for Biotechnology Information (NCBI) on the worldwide web, ncbi. nlm. nih. gov) . Another non-limiting example of a mathematical algorithm utilized for the comparison of sequences is the algorithm of Myers and Miller, CABIOS 4: 11-17 (1998) . Such an algorithm is incorporated in the ALIGN program (version 2.0) which is part of the GCG sequence alignment software package. When utilizing the ALIGN program for comparing amino acid sequences, a PAM120 weight residue table, a gap length penalty of 12, and a gap penalty of 4 can be used.

In some embodiments, amino acid sequence modification (s) of the CARs described herein are contemplated. For example, it may be desirable to optimize the binding affinity and/or other biological properties of the extracellular domain, including but not limited to specificity, thermostability, expression level, effector functions, glycosylation, reduced immunogenicity, or solubility. Thus, in addition to the extracellular domain described herein, it is contemplated that variants of the domains described herein can be prepared. For example, scFv variants can be prepared by introducing appropriate nucleotide changes into the encoding DNA, and/or by synthesis of the desired antibody or polypeptide. Those skilled in the art who appreciate that amino acid changes may alter post-translational processes of the antibody.

Variations may be a substitution, deletion, or insertion of one or more codons encoding the polypeptide that results in a change in the amino acid sequence as compared with the original antibody or polypeptide. Sites of interest for substitutional mutagenesis include the CDRs and FRs.

Amino acid substitutions can be the result of replacing one amino acid with another amino acid having similar structural and/or chemical properties, such as the replacement of a leucine with a serine, e.g., conservative amino acid replacements. Standard techniques known to those of skill in the art can be used to introduce mutations in the nucleotide sequence encoding a molecule provided herein, including, for example, site-directed mutagenesis and PCR-mediated mutagenesis which results in amino acid substitutions. Insertions or deletions may optionally be in the range of about 1 to 5 amino acids. In certain embodiments, the substitution, deletion, or insertion includes fewer than 25 amino acid substitutions, fewer than 20 amino acid substitutions, fewer than 15 amino acid substitutions, fewer than 10 amino acid substitutions, fewer than 5 amino acid substitutions, fewer than 4 amino acid substitutions, fewer than 3 amino acid substitutions, or fewer than 2 amino acid substitutions relative to the original molecule. In a specific embodiment, the substitution is a conservative amino acid substitution made at one or more predicted non-essential amino acid residues. The variation allowed may be determined by systematically making insertions, deletions, or substitutions of amino acids in the sequence and testing the resulting variants for activity exhibited by the parental polypeptides.

The polypeptides generated by conservative amino acid substitutions are included in the present disclosure. In a conservative amino acid substitution, an amino acid residue is replaced with an amino acid residue having a side chain with a similar charge. As described above, families of amino acid residues having side chains with similar charges have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine) , acidic side chains (e.g., aspartic acid, glutamic acid) , uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine) , nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan) , beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine) . Alternatively, mutations can be introduced randomly along all or part of the coding sequence, such as by saturation mutagenesis, and the resultant mutants can be screened for biological activity to identify mutants that retain activity. Following mutagenesis, the encoded protein can be expressed and the activity of the protein can be determined. Conservative (e.g., within an amino acid group with similar properties and/or side chains) substitutions may be made, so as to maintain or not significantly change the properties.

Amino acids may be grouped according to similarities in the properties of their side chains (see, e.g., Lehninger, Biochemistry 73-75 (2d ed. 1975) ) : (1) non-polar: Ala (A) , Val (V) , Leu (L) , Ile (I) , Pro (P) , Phe (F) , Trp (W) , Met (M) ; (2) uncharged polar: Gly (G) , Ser (S) , Thr (T) , Cys (C) , Tyr (Y) , Asn (N) , Gln (Q) ; (3) acidic: Asp (D) , Glu (E) ; and (4) basic: Lys (K) , Arg (R) , His (H) . Alternatively, naturally occurring residues may be divided into groups based on common side-chain properties: (1) hydrophobic: Norleucine, Met, Ala, Val, Leu, Ile; (2) neutral hydrophilic: Cys, Ser, Thr, Asn, Gln; (3) acidic: Asp, Glu; (4) basic: His, Lys, Arg; (5) residues that influence chain orientation: Gly, Pro; and (6) aromatic: Trp, Tyr, Phe. For example, any cysteine residue not involved in maintaining the proper conformation of the antibody also may be substituted, for example, with another amino acid, such as alanine or serine, to improve the oxidative stability of the molecule and to prevent aberrant crosslinking. Non-conservative substitutions will entail exchanging a member of one of these classes for another class.

One type of substitutional variant involves substituting one or more hypervariable region residues of a parent antibody (e.g., a humanized or human antibody) or fragment thereof in the extraceullar antigen binding domain of the present CARs. Generally, the resulting variant (s) selected for further study will have modifications (e.g., improvements) in certain biological properties (e.g., increased affinity, reduced immunogenicity) relative to the parent antibody and/or will have substantially retained certain biological properties of the parent antibody. An exemplary substitutional variant is an affinity matured antibody, which may be conveniently generated, e.g., using phage display-based affinity maturation techniques such as those described herein. Briefly, one or more CDR residues are mutated and the variant antibodies displayed on phage and screened for a particular biological activity (e.g. binding affinity) .

Alterations (e.g., substitutions) may be made in CDRs, e.g., to improve antibody affinity. Such alterations may be made in CDR “hotspots, ” i.e., residues encoded by codons that undergo mutation at high frequency during the somatic maturation process (see, e.g., Chowdhury, Methods Mol. Biol. 207: 179-196 (2008) ) , and/or SDRs (a-CDRs) , with the resulting variant antibody or fragment thereof being tested for binding affinity. Affinity maturation by constructing and reselecting from secondary libraries has been described, e.g., in Hoogenboom et al. in Methods in Molecular Biology 178: 1-37 (O’Brien et al., ed., Human Press, Totowa, NJ,

. ) In some embodiments of affinity maturation, diversity is introduced into the variable genes chosen for maturation by any of a variety of methods (e.g., error-prone PCR, chain shuffling, or oligonucleotide-directed mutagenesis) . A secondary library is then created. The library is then screened to identify any antibody variants with the desired affinity. Another method to introduce diversity involves CDR-directed approaches, in which several CDR residues (e.g., 4-6 residues at a time) are randomized. CDR residues involved in antigen binding may be specifically identified, e.g., using alanine scanning mutagenesis or modeling.

In some embodiments, substitutions, insertions, or deletions may occur within one or more CDRs so long as such alterations do not substantially reduce the ability of the antibody to bind antigen. For example, conservative alterations (e.g., conservative substitutions as provided herein) that do not substantially reduce binding affinity may be made in CDRs. In some embodiments, each CDR either is unaltered, or contains no more than one, two or three amino acid substitutions.

A useful method for identification of residues or regions of an antibody that may be targeted for mutagenesis is called “alanine scanning mutagenesis” as described by Cunningham and Wells, Science, 244: 1081-1085 (1989) . In this method, a residue or group of target residues (e.g., charged residues such as Arg, Asp, His, Lys, and Glu) are identified and replaced by a neutral or negatively charged amino acid (e.g., alanine or polyalanine) to determine whether the interaction of the antibody with antigen is affected. Further substitutions may be introduced at the amino acid locations demonstrating functional sensitivity to the initial substitutions.

Alternatively, or additionally, a crystal structure of an antigen-antibody complex to identify contact points between the antibody and antigen. Such contact residues and neighboring residues may be targeted or eliminated as candidates for substitution. Variants may be screened to determine whether they contain the desired properties.

Amino acid sequence insertions include amino-and/or carboxyl-terminal fusions ranging in length from one residue to polypeptides containing a hundred or more residues, as well as intrasequence insertions of single or multiple amino acid residues. Examples of terminal insertions include an antibody with an N-terminal methionyl residue. Other insertional variants of the antibody molecule include the fusion to the N-or C-terminus of the antibody to an enzyme (e.g., for ADEPT) or a polypeptide which increases the serum half-life of the antibody.

The variations can be made using methods known in the art such as oligonucleotide-mediated (site-directed) mutagenesis, alanine scanning, and PCR mutagenesis. Site-directed mutagenesis (see, e.g., Carter, Biochem J. 237: 1-7 (1986) ; and Zoller et al., Nucl. Acids Res. 10: 6487-500 (1982) ) , cassette mutagenesis (see, e.g., Wells et al., Gene 34: 315-23 (1985) ) , or other known techniques can be performed on the cloned DNA to produce the antibody variant DNA.

5.2.2. Chimeric Co-stimulatory Receptors

A chimeric co-stimulatory receptor provided herein comprises an extracellular binding domain capable of binding to an antigen, a transmembrane domain, an intracellular domain devoid of a primary signaling domain and comprising a co-stimulatory domain.

In certain embodiments, the extracelluar domain, transmembrane domain, and co-stimulatory domain of the chimeric co-stimulatory receptors provided herein can be as described in Section 5.2.1 above and as described below. Optionally, the chimeric co-stimulatory receptors provided herein also comprise a hinge region and/or signal peptide, each of which can be as described in Section 5.2.1 above as well.

Non-limiting examples of the antigen binding domain include, but are not limited to, a monoclonal antibody, a polyclonal antibody, a recombinant antibody, a human antibody, a humanized antibody, a murine antibody, or a functional derivative, variant or fragment thereof, including, but not limited to, a Fab, a Fab', a F (ab') ₂, an Fv, a single-chain Fv (scFv) , minibody, a diabody, and a single-domain antibody such as a heavy chain variable domain (VH) , a light chain variable domain (VL) and a variable domain (V _HH) of camelid derived nanobody. In some embodiments, the first antigen binding domain comprises a single-domain antibody (sdAb) . In some embodiments, the first antigen binding domain comprises an sdAb binding to an epitope disclosed herein. In some embodiments, the first antigen binding domain comprises a V _HH. In some embodiments, the first antigen binding domain comprises a V _HH binding to an epitope disclosed herein. In some embodiments, the antigen binding domain comprises at least one of a Fab, a Fab’, a F (ab’) ₂, an Fv, and an scFv. In some embodiments, the antigen binding domain comprises an antibody mimetic. Antibody mimetics refer to molecules which can bind a target molecule with an affinity comparable to an antibody, and include single-chain binding molecules, cytochrome b562-based binding molecules, fibronectin or fibronectin-like protein scaffolds (e.g., adnectins) , lipocalin scaffolds, calixarene scaffolds, A-domains and other scaffolds. In some embodiments, an antigen binding domain comprises a transmembrane receptor, or any derivative, variant, or fragment thereof. For example, an antigen binding domain can comprise at least a ligand binding domain of a transmembrane receptor.

In some embodiments, the antigen binding domain can comprise a scFv. A scFv can be derived from an antibody for which the sequences of the variable regions are known. In some embodiments, a scFv can be derived from an antibody sequence obtained from an available mouse hybridoma. A scFv can be obtained from whole-exomic sequencing of a tumor cell or primary cell. In some embodiments, a scFv can be altered. For instance, a scFv may be modified in a variety of ways. In some cases, a scFv can be mutated, so that the scFv may have higher affinity to its target. In some cases, the affinity of the scFv for its target can be optimized for targets expressed at low levels on normal tissues. This optimization can be performed to minimize potential toxicities, such as cytokine release syndrome. In other cases, the cloning of a scFv that has a higher affinity for the membrane bound form of a target can be preferable over its soluble form counterpart. This modification can be performed if some targets can also be detected in soluble form at different levels and their targeting can cause unintended toxicity, such as cytokine release syndrome.

In some embodiments, the antigen binding domain can comprise one member of an interacting pair. For example, the antigen binding domain may be one member, or a fragment thereof, of an interacting pair comprising a receptor and a ligand. Either the receptor or ligand, or fragments thereof, may be referred to as the antigen binding domain. The other member which is not referred to as the antigen binding domain can comprise the epitope to which the antigen binding domain specifically binds. In some embodiments, the antigen binding domain and/or the second antigen binding domain comprises a receptor which specifically binds to a ligand. The receptor can comprise G-protein coupled receptors (GPCRs) ; integrin receptors; cadherin receptors; catalytic receptors including receptors possessing enzymatic activity and receptors which, rather than possessing intrinsic enzymatic activity, act by stimulating non-covalently associated enzymes (e.g., kinases) ; death receptors such as members of the tumor necrosis factor receptor (TNFR) superfamily; cytokine receptors; immune receptors; and the like. In some embodiments, the antigen binding domain and/or the second antigen binding domain comprises a ligand which is bound by a receptor.

An antigen binding domain of a chimeric co-stimulatory receptor provided herein can be linked to an intracellular signaling domain via a transmembrane domain. A transmembrane domain can be a membrane spanning segment. A transmembrane domain of a subject chimeric co-stimulatory receptor can anchor the chimeric co-stimulatory receptor to the plasma membrane of a cell, for example an immune cell. In some embodiments, the membrane spanning segment comprises a polypeptide. The membrane spanning polypeptide linking the antigen binding domain and the intracellular signaling domain of the chimeric co-stimulatory receptor can have any suitable polypeptide sequence. In some cases, the membrane spanning polypeptide comprises a polypeptide sequence of a membrane spanning portion of an endogenous or wild-type membrane spanning protein. In some embodiments, the membrane spanning polypeptide comprises a polypeptide sequence having at least 1 (e.g., at least 2, 3, 4, 5, 6, 7, 8, 9, 10 or greater) of an amino acid substitution, deletion, and insertion compared to a membrane spanning portion of an endogenous or wild-type membrane spanning protein. In some embodiments, the membrane spanning polypeptide comprises a non-natural polypeptide sequence, such as the sequence of a polypeptide linker. The polypeptide linker may be flexible or rigid. The polypeptide linker can be structured or unstructured. In some embodiments, the membrane spanning polypeptide transmits a signal from an extracellular region of a cell to an intracellular region, for via the antigen binding domain. For example, a native transmembrane portion of CD28 can be used in a chimeric co-stimulatory receptor. In other cases, a native transmembrane portion of CD8 alpha can also be used in a chimeric co-stimulatory receptor.

A chimeric co-stimulatory receptor provided herein can comprise an intracellular signaling domain. In some embodiments, the intracellular signaling domain of a chimeric co-stimulatory receptor provided herein is devoid of a signaling domain (primary signaling domain) , or any derivative, variant, or fragment thereof, involved in immune cell signaling. In some embodiments, the primary signaling domain is as described in Section 5.2.1 above. The signaling domain can induce activity of an immune cell. The signaling domain can transduce the effector function signal and direct the cell to perform a specialized function. The signaling domain can comprise signaling domains of other molecules. In some embodiments, a chimeric co-stimulatory receptor provided herein comprises an intracellular signaling domain devoid of a signaling domain of CD3 zeta. As used herein, the expression of “an intracellular signaling domain devoid of a signaling domain of CD3 zeta” or a similar expression refers to an intracellular signaling domain devoid of a fully functional signaling domain of CD3 zeta, and thus includes an intracellular signaling domain comprising a variant of the signaling domain of CD3 zeta that is not fully funcational in CD3 zeta mediated signaling.

In some cases, the intracellular signaling domain of a subject chimeric co-stimulatory receptor can be devoid of at least a portion of a signaling domain of CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of the entire portion of the signaling domain of CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or more of the signaling domain of the CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of at most 100%, 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less of the signaling domain of the CD3 zeta.

In some cases, the intracellular signaling domain of a subject chimeric co-stimulatory receptor can be devoid of at least one amino acid of a signaling domain of CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of the entire amino acid sequence of the signaling domain of CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or more of the amino acid sequence of the signaling domain of the CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of at most 100%, 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less of the amino acid sequence of the signaling domain of the CD3 zeta.

In some cases, the intracellular signaling domain of a subject chimeric co-stimulatory receptor can be devoid of at least a portion of an intracellular domain of CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of the entire intracellular domain of CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or more of the intracellular domain of the CD3 zeta. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of at most 100%, 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less of the intracellular domain of the CD3 zeta.

In other embodiments, a subject chimeric co-stimulatory receptor comprises an intracellular domain devoid of an immune cell signaling domain that can be involved in regulating primary activation of the TCR complex in either a stimulatory way or an inhibitory way. The intracellular signaling domain of a subject chimeric co-stimulatory receptor can be devoid of a signaling domain of an Fcγ receptor (FcγR) , an Fcε receptor (FcεR) , an Fcα receptor (FcαR) , neonatal Fc receptor (FcRn) , CD3, CD3 ζ, CD3 γ, CD3 δ, CD3 ε, CD4, CD5, CD8, CD21, CD22, CD28, CD32, CD40L (CD154) , CD45, CD66d, CD79a, CD79b, CD80, CD86, CD278 (also known as ICOS) , CD247 ζ, CD247 η, DAP10, DAP12, FYN, LAT, Lck, MAPK, MHC complex, NFAT, NF-κB, PLC-γ, iC3b, C3dg, C3d, and Zap70.

In some embodiments, the intracellular signaling domain of a chimeric co-stimulatory receptor of a subject system is devoid of an immunoreceptor tyrosine-based activation motif or ITAM. ITAM comprises two repeats of the amino acid sequence YxxL/I separated by 6-8 amino acids, wherein each x is independently any amino acid, producing the conserved motif YxxL/Ix _(6- ₈₎YxxL/I. ITAM can be modified, for example, by phosphorylation when the antigen binding domain is bound to an epitope. A phosphorylated ITAM can function as a docking site for other proteins, for example proteins involved in various signaling pathways.

In some embodiments, the intracellular signaling domain of a subject chimeric co-stimulatory receptor is devoid of FcγR signaling domain (e.g., ITAM) . The FcγR signaling domain can be selected from FcγRI (CD64) , FcγRIIA (CD32) , FcγRIIB (CD32) , FcγRIIIA (CD16a) , and FcγRIIIB (CD16b) . In some embodiments, the intracellular signaling domain is devoid of FcεR signaling domain (e.g., ITAM) . The FcεR signaling domain can be selected from FcεRI and FcεRII (CD23) . In some embodiments, the intracellular signaling domain is devoid of FcαR signaling domain (e.g., ITAM) . The FcαR signaling domain can be selected from FcαRI (CD89) and Fcα/μR. In some embodiments, the intracellular signaling domain is devoid of an ITAM of CD3 zeta. In some embodiments, a subject chimeric co-stimulatory receptor comprises an intracellular signaling domain devoid of CD3 zeta.

In some embodiments, an intracellular signaling domain of a subject chimeric co-stimulatory receptor is devoid of an immunoreceptor tyrosine-based inhibition motif or ITIM. ITIM can comprise a conserved sequence of amino acids (S/I/V/LxYxxI/V/L, SEQ ID NO: 59) that is found in the cytoplasmic tails of some inhibitory receptors of the immune system. ITIM can be modified, for example phosphorylated, by enzymes such as a Src kinase family member (e.g., Lck) . Following phosphorylation, other proteins, including enzymes, can be recruited to the ITIM. These other proteins include, but are not limited to, enzymes such as the phosphotyrosine phosphatases SHP-1 and SHP-2, the inositol-phosphatase called SHIP, and proteins having one or more SH2 domains (e.g., ZAP70) . A intracellular signaling domain can comprise a signaling domain (e.g., ITIM) of BTLA, CD5, CD31, CD66a, CD72, CMRF35H, DCIR, EPO-R, FcγRIIB (CD32) , Fc receptor-like protein 2 (FCRL2) , Fc receptor-like protein 3 (FCRL3) , Fc receptor-like protein 4 (FCRL4) , Fc receptor-like protein 5 (FCRL5) , Fc receptor-like protein 6 (FCRL6) , protein G6b (G6B) , interleukin 4 receptor (IL4R) , immunoglobulin superfamily receptor translocation-associated 1 (IRTA1) , immunoglobulin superfamily receptor translocation-associated 2 (IRTA2) , killer cell immunoglobulin-like receptor 2DL1 (KIR2DL1) , killer cell immunoglobulin-like receptor 2DL2 (KIR2DL2) , killer cell immunoglobulin-like receptor 2DL3 (KIR2DL3) , killer cell immunoglobulin-like receptor 2DL4 (KIR2DL4) , killer cell immunoglobulin-like receptor 2DL5 (KIR2DL5) , killer cell immunoglobulin-like receptor 3DL1 (KIR3DL1) , killer cell immunoglobulin-like receptor 3DL2 (KIR3DL2) , leukocyte immunoglobulin-like receptor subfamily B member 1 (LIR1) , leukocyte immunoglobulin-like receptor subfamily B member 2 (LIR2) , leukocyte immunoglobulin-like receptor subfamily B member 3 (LIR3) , leukocyte immunoglobulin-like receptor subfamily B member 5 (LIR5) , leukocyte immunoglobulin-like receptor subfamily B member 8 (LIR8) , leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1) , mast cell function-associated antigen (MAFA) , NKG2A, natural cytotoxicity triggering receptor 2 (NKp44) , NTB-A, programmed cell death protein 1 (PD-1) , PILR, SIGLECL1, sialic acid binding Ig like lectin 2 (SIGLEC2 or CD22) , sialic acid binding Ig like lectin 3 (SIGLEC3 or CD33) , sialic acid binding Ig like lectin 5 (SIGLEC5 or CD170) , sialic acid binding Ig like lectin 6 (SIGLEC6) , sialic acid binding Ig like lectin 7 (SIGLEC7) , sialic acid binding Ig like lectin 10 (SIGLEC10) , sialic acid binding Ig like lectin 11 (SIGLEC11) , sialic acid binding Ig like lectin 4 (SIGLEC4) , sialic acid binding Ig like lectin 8 (SIGLEC8) , sialic acid binding Ig like lectin 9 (SIGLEC9) , platelet and endothelial cell adhesion molecule 1 (PECAM-1) , signal regulatory protein (SIRP) , and signaling threshold regulating transmembrane adaptor 1 (SIT) .

In some embodiments, the intracellular signaling domain is devoid of both ITAM and ITIM domains.

In some cases, the intracellular signaling domain of a subject chimeric co-stimulatory receptor can be devoid of at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more ITAM domains of TCR. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of at most 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 ITAM domain of TCR. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can be devoid of the entire ITAM domains of TCR.

The intracellular signaling domain of a subject chimeric co-stimulatory receptor provided herein includes a co-stimulatory domain. In some embodiments, a co-stimulatory domain, for example from co-stimulatory molecule, can provide co-stimulatory signals for immune cell signaling. In some embodiments, a costimulatory domain is operable to regulate a proliferative and/or survival signal in the immune cell. In some embodiments, a co-stimulatory signaling domain comprises a signaling domain of a MHC class I protein, MHC class II protein, TNF receptor protein, immunoglobulin-like protein, cytokine receptor, integrin, signaling lymphocytic activation molecule (SLAM protein) , activating NK cell receptor, BTLA, or a Toll ligand receptor. In some embodiments, the costimulatory domain comprises a signaling domain of a molecule selected from the group consisting of: 2B4/CD244/SLAMF4, 4-1BB/TNFSF9/CD137, B7-1/CD80, B7-2/CD86, B7-H1/PD-L1, B7-H2, B7-H3, B7-H4, B7-H6, B7-H7, BAFF R/TNFRSF13C, BAFF/BLyS/TNFSF13B, BLAME/SLAMF8, BTLA/CD272, CD100 (SEMA4D) , CD103, CD11a, CD11b, CD11c, CD11d, CD150, CD160 (BY55) , CD18, CD19, CD2, CD200, CD229/SLAMF3, CD27 Ligand/TNFSF7, CD27/TNFRSF7, CD28, CD29, CD2F-10/SLAMF9, CD30 Ligand/TNFSF8, CD30/TNFRSF8, CD300a/LMIR1, CD4, CD40 Ligand/TNFSF5, CD40/TNFRSF5, CD48/SLAMF2, CD49a, CD49D, CD49f, CD5, CD53, CD58/LFA-3, CD69, CD7, CD8 α, CD8 β, CD82/Kai-1, CD84/SLAMF5, CD90/Thy1, CD96, CDS, CEACAM1, CRACC/SLAMF7, CRTAM, CTLA-4, DAP12, Dectin-1/CLEC7A, DNAM1 (CD226) , DPPIV/CD26, DR3/TNFRSF25, EphB6, GADS, Gi24/VISTA/B7-H5, GITR Ligand/TNFSF18, GITR/TNFRSF18, HLA Class I, HLA-DR, HVEM/TNFRSF14, IA4, ICAM-1, ICOS/CD278, Ikaros, IL2R β, IL2R γ, IL7R α, Integrin α4/CD49d, Integrin α4β1, Integrin α4β7/LPAM-1, IPO-3, ITGA4, ITGA6, ITGAD, ITGAE, ITGAL, ITGAM, ITGAX, ITGB1, ITGB2, ITGB7, KIRDS2, LAG-3, LAT, LIGHT/TNFSF14, LTBR, Ly108, Ly9 (CD229) , lymphocyte function associated antigen-1 (LFA-1) , Lymphotoxin-α/TNF-β, NKG2C, NKG2D, NKp30, NKp44, NKp46, NKp80 (KLRF1) , NTB-A/SLAMF6, OX40 Ligand/TNFSF4, OX40/TNFRSF4, PAG/Cbp, PD-1, PDCD6, PD-L2/B7-DC, PSGL1, RELT/TNFRSF19L, SELPLG (CD162) , SLAM (SLAMF1) , SLAM/CD150, SLAMF4 (CD244) , SLAMF6 (NTB-A) , SLAMF7, SLP-76, TACI/TNFRSF13B, TCL1A, TCL1B, TIM-1/KIM-1/HAVCR, TIM-4, TL1A/TNFSF15, TNF RII/TNFRSF1B, TNF-α, TRANCE/RANKL, TSLP, TSLP R, VLA1, and VLA-6. In some embodiments, the intracellular signaling domain comprises multiple costimulatory domains, for example at least two, e.g., at least 3, 4, or 5 costimulatory domains. Co-stimulatory signaling regions may provide a signal synergistic with the primary effector activation signal and can complete the requirements for activation of a T cell. In some embodiments, the addition of co-stimulatory domains to the chimeric co-stimulatory receptor can enhance the efficacy and persistence of the immune cells provided herein. In some embodiments, the intracellular signaling domain of a subject chimeric co-stimulatory receptor comprises only a costimulatory domain, which is also referred as “costimulatory only chimeric co-stimulatory receptor. ”

In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can include at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more co-stimulatory domains. In some cases, the intracellular signaling domain of the subject chimeric co-stimulatory receptor can include at most 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 co-stimulatory domain. Examples of costimulatory signaling domains are provided in Table 2.

Table 2. Exemplary Intracellular Co-stimulatory Signaling Domains

In some embodiments, the intracellular domain of a subject chimeric co-stimulatory receptor is devoid of a signaling domain and comprises a co-stimulatory domain. As an example, a chimeric co-stimulatory receptor is devoid of a CD3 zeta domain and comprises a single co-stimulatory domain such as CD27, CD28 or 4-1BB. As another example, a chimeric co-stimulatory receptor is devoid of CD3 zeta domain and comprises two co-stimulatory domains, such as CD28/OX40 or CD28/4-1BB. As another example, a chimeric co-stimulatory receptor is devoid of a CD3 zeta domain and comprises more than two stimulatory domains. In some embodiments, the intracellular domain of a subject chimeric co-stimulatory receptor is devoid of an ITAM and comprises a co-stimulatory domain. As an example, a chimeric co-stimulatory receptor is devoid of an ITAM and comprises a single co-stimulatory domain such as CD27, CD28 or 4-1BB. As another example, a chimeric co-stimulatory receptor is devoid of an ITAM and comprises two co-stimulatory domains, such as CD28/OX40 or CD28/4-1BB. As another example, a chimeric co-stimulatory receptor is devoid of an ITAM and comprises more than two stimulatory domains. In some embodiments, the co-stimulatory domain is derived from CD28.

In some embodiments, a subject chimeric co-stimulatory receptor may not be configured to form a complex with one another. As demonstrated in Section 6 below, certain mutations that reduce dimerization of chimeric co-stimulatory receptor (such as certain cysteine-to-serine mutations in the CD28 hinge and transmembrane domains) abrogated the non-specificity of the present chimeric co-stimulatory receptor armored CAR-T. Thus, in some embodiments, the transmembrane domain of the present chimeric co-stimulatory receoptor comprises one or more mutations that reduce dimerization between the receoptors. In other emodiments, the hinge region of the present chimeric co-stimulatory receoptor comprises one or more mutations that reduce dimerization between the receptors. In some embodiments, the present chimeric co-stimulatory receptor comprises mutations at both hinge and transmembrane regions (such as cysteine to serine mutations) .

In some embodiments, a subject chimeric co-stimulatory receptor may be configured to form a complex with one another as a multimeric structure. In some cases, the subject chimeric co-stimulatory receptor may be configured to form at least a (1) monomer, (2) dimer, (3) trimer, (4) tetramer, (5) pentamer, (6) hexamer, (7) heptamer, (8) octamer, (9) decamer, (10) dodecamer, or (11) higher multimer. In some cases, the subject chimeric co-stimulatory receptor may be configured to form a (1) monomer, (2) dimer, (3) trimer, (4) tetramer, (5) pentamer, (6) hexamer, (7) heptamer, (8) octamer, (9) decamer, (10) dodecamer, and/or (11) higher multimer. In some cases, the subject chimeric co-stimulatory receptor may be configured to form a (1a) homo-dimer and/or (1b) hetero-dimer; (2a) homo-trimer and/or (2b) hetero-trimer; (3a) homo-tetramer and/or (3b) hetero-tetramer; (4a) homo-pentamer and/or (4b) hetero-pentamer; (5a) homo-hexamer and/or (5b) hetero-hexamer; (6a) homo-octamer and/or (6b) hetero-octamer; (7a) homo-decamer and/or (7b) hetero-decamer; and/or (8a) homo-dodecamer and/or (8b) hetero-dodecamer.

In some embodiments, a subject chimeric co-stimulatory receptor can comprise a hinge or a spacer. The hinge or the spacer can refer to a segment between the antigen binding domain and the transmembrane domain. In some embodiments, a hinge can be used to provide flexibility to an antigen binding domain, e.g., scFv. In some embodiments, a hinge can be used to detect the expression of a chimeric co-stimulatory receptor on the surface of a cell, for example when antibodies to detect the scFv are not functional or available. In some cases, the hinge is derived from an immunoglobulin molecule and may require optimization depending on the location of the first epitope or second epitope on the target. In some cases, a hinge may not belong to an immunoglobulin molecule but instead to another molecule such the native hinge of a CD8 alpha molecule. A CD8 alpha hinge can contain cysteine and proline residues which many play a role in the interaction of a CD8 co-receptor and MHC molecule. In some embodiments, a cysteine and proline residue can influence the performance of a chimeric co-stimulatory receptor and may therefore be engineered to influence a chimeric co-stimulatory receptor performance.

A hinge can be of any suitable length. In some embodiments, a chimeric co-stimulatory receptor’s hinge can be size tunable and can compensate to some extent in normalizing the orthogonal synapse distance between a chimeric co-stimulatory receptor expressing cell and a target cell. This topography of the immunological synapse between the chimeric co-stimulatory receptor expressing cell and target cell can also define a distance that cannot be functionally bridged by a chimeric co-stimulatory receptor due to a membrane-distal epitope on a cell-surface target molecule that, even with a short hinge chimeric co-stimulatory receptor, cannot bring the synapse distance in to an approximation for signaling. Likewise, membrane-proximal chimeric co-stimulatory receptor target antigen epitopes have been described for which signaling outputs are only observed in the context of a long hinge chimeric co-stimulatory receptor. A hinge disclosed herein can be tuned according to the single chain variable fragment region that can be used.

5.2.3 Engineered Immune Effector Cells

Immune Effector Cells

“Immune effector cells” are immune cells that can perform immune effector functions. In some embodiments, the immune effector cells express at least FcγRIII and perform ADCC effector function. Examples of immune effector cells which mediate ADCC include peripheral blood mononuclear cells (PBMC) , natural killer (NK) cells, monocytes, cytotoxic T cells, neutrophils, and eosinophils.

In some embodiments, the immune effector cells are T cells. In some embodiments, the T cells are CD4+/CD8-, CD4-/CD8+, CD4+/CD8+, CD4-/CD8-, or combinations thereof. In some embodiments, the T cells produce IL-2, TFN, and/or TNF upon expressing the CAR and binding to the target cells. In some embodiments, the CD8+ T cells lyse antigen-specific target cells upon expressing the CAR or TCR and binding to the target cells.

In some embodiments, the immune effector cells are NK cells. In other embodiments, the immune effector cells can be established cell lines, for example, NK-92 cells.

In some embodiments, the immune effector cells are differentiated from a stem cell, such as a hematopoietic stem cell, a pluripotent stem cell, an iPS, or an embryonic stem cell.

The engineered immune effector cells are prepared by introducing the polypeptide provided herein into the immune effector cells, such as T cells. In some embodiments, the polypeptide is introduced to the immune effector cells by transfecting any one of the isolated nucleic acids or any one of the vectors described above.

Methods of introducing vectors or isolated nucleic acids into a mammalian cell are known in the art. The vectors described can be transferred into an immune effector cell by physical, chemical, or biological methods.

Physical methods for introducing the vector into an immune effector cell include calcium phosphate precipitation, lipofection, particle bombardment, microinjection, electroporation, and the like. Methods for producing cells comprising vectors and/or exogenous nucleic acids are well-known in the art. See, e.g., Sambrook et al. (2001) Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, New York. In some embodiments, the vector is introduced into the cell by electroporation.

Biological methods for introducing the vector into an immune effector cell include the use of DNA and RNA vectors. Viral vectors have become the most widely used method for inserting genes into mammalian, e.g., human cells.

Chemical means for introducing the vector into an immune effector cell include colloidal dispersion systems, such as macromolecule complexes, nanocapsules, microspheres, beads, and lipid-based systems including oil-in-water emulsions, micelles, mixed micelles, and liposomes. An exemplary colloidal system for use as a delivery vehicle in vitro is a liposome (e.g., an artificial membrane vesicle) .

In some embodiments, RNA molecules encoding any of the polypeptides described herein may be prepared by a conventional method (e.g., in vitro transcription) and then introduced into the immune effector cells via known methods such as mRNA electroporation. See, e.g., Rabinovich et al., Human Gene Therapy 17: 1027-1035 (2006) .

In some embodiments, the transduced or transfected immune effector cell is propagated ex vivo after introduction of the vector or isolated nucleic acid. In some embodiments, the transduced or transfected immune effector cell is cultured to propagate for at least about any of 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 10 days, 12 days, or 14 days. In some embodiments, the transduced or transfected immune effector cell is further evaluated or screened to select the engineered mammalian cell.

Reporter genes may be used for identifying potentially transfected cells and for evaluating the functionality of regulatory sequences. In general, a reporter gene is a gene that is not present in or expressed by the recipient organism or tissue and that encodes a polypeptide whose expression is manifested by some easily detectable property, e.g., enzymatic activity. Expression of the reporter gene is assayed at a suitable time after the DNA has been introduced into the recipient cells. Suitable reporter genes may include genes encoding luciferase, beta-galactosidase, chloramphenicol acetyl transferase, secreted alkaline phosphatase, or the green fluorescent protein gene (e.g., Ui-Tei et al. FEBS Letters 479: 79-82 (2000) ) . Suitable expression systems are well known and may be prepared using known techniques or obtained commercially.

Other methods to confirm the presence of the nucleic acid encoding the polypeptide in the engineered immune effector cell, include, for example, molecular biological assays well known to those of skill in the art, such as Southern and Northern blotting, RT-PCR and PCR; biochemical assays, such as detecting the presence or absence of a particular peptide, e.g., by immunological methods (such as ELISAs and Western blots) .

Sources of T Cells

In some embodiments, prior to expansion and genetic modification of the T cells, a source of T cells is obtained from a subject. T cells can be obtained from a number of sources, including peripheral blood mononuclear cells, bone marrow, lymph node tissue, cord blood, thymus tissue, tissue from a site of infection, ascites, pleural effusion, spleen tissue, and tumors. In some embodiments, any number of T cell lines available in the art, may be used. In some embodiments, T cells can be obtained from a unit of blood collected from a subject using any number of techniques known to the skilled artisan, such as Ficoll ^TM separation. In some embodiments, cells from the circulating blood of an individual are obtained by apheresis. The apheresis product typically contains lymphocytes, including T cells, monocytes, granulocytes, B cells, other nucleated white blood cells, red blood cells, and platelets. In some embodiments, the cells collected by apheresis may be washed to remove the plasma fraction and to place the cells in an appropriate buffer or media for subsequent processing steps. In some embodiments, the cells are washed with phosphate buffered saline (PBS) . In some embodiments, the wash solution lacks calcium and may lack magnesium or may lack many if not all divalent cations. Initial activation steps in the absence of calcium may lead to magnified activation. As those of ordinary skill in the art would readily appreciate a washing step may be accomplished by methods known to those in the art, such as by using a semi-automated “flow-through” centrifuge (for example, the Cobe 2991 cell processor, the Baxter CytoMate, or the Haemonetics Cell Saver 5) according to the manufacturer's instructions. After washing, the cells may be resuspended in a variety of biocompatible buffers, such as, for example, Ca ²⁺-free, Mg ²⁺-free PBS, PlasmaLyte A, or other saline solution with or without buffer. Alternatively, the undesirable components of the apheresis sample may be removed and the cells directly resuspended in culture media.

In some embodiments, T cells are isolated from peripheral blood lymphocytes by lysing the red blood cells and depleting the monocytes, for example, by centrifugation through a PERCOLL ^TM gradient or by counterflow centrifugal elutriation. A specific subpopulation of T cells, such as CD3+, CD28+, CD4+, CD8+, CD45RA+, and CD45RO+T cells, can be further isolated by positive or negative selection techniques. For example, in some embodiments, T cells are isolated by incubation with anti-CD3/anti-CD28 (i.e., 3×28) -conjugated beads, such as

M-450 CD3/CD28 T, for a time period sufficient for positive selection of the desired T cells. In some embodiments, the time period is about 30 minutes. In a further embodiment, the time period ranges from 30 minutes to 36 hours or longer and all integer values there between. In a further embodiment, the time period is at least 1, 2, 3, 4, 5, or 6 hours. In some embodiments, the time period is 10 to 24 hours. In some embodiments, the incubation time period is 24 hours. For isolation of T cells from patients with leukemia, use of longer incubation times, such as 24 hours, can increase cell yield. Longer incubation times may be used to isolate T cells in any situation where there are few T cells as compared to other cell types, such in isolating tumor infiltrating lymphocytes (TIL) from tumor tissue or from immune-compromised individuals. Further, use of longer incubation times can increase the efficiency of capture of CD8+ T cells. Thus, in some embodiments, by simply shortening or lengthening the time T cells are allowed to bind to the CD3/CD28 beads and/or by increasing or decreasing the ratio of beads to T cells, subpopulations of T cells can be preferentially selected for or against at culture initiation or at other time points during the process. Additionally, by increasing or decreasing the ratio of anti-CD3 and/or anti-CD28 antibodies on the beads or other surface, subpopulations of T cells can be preferentially selected for or against at culture initiation or at other desired time points. The skilled artisan would recognize that multiple rounds of selection can also be used. In some embodiments, it may be desirable to perform the selection procedure and use the “unselected” cells in the activation and expansion process. “Unselected” cells can also be subjected to further rounds of selection.

Enrichment of a T cell population by negative selection can be accomplished with a combination of antibodies directed to surface markers unique to the negatively selected cells. One method is cell sorting and/or selection via negative magnetic immunoadherence or flow cytometry that uses a cocktail of monoclonal antibodies directed to cell surface markers present on the cells negatively selected. For example, to enrich for CD4+ cells by negative selection, a monoclonal antibody cocktail typically includes antibodies to CD14, CD20, CD11b, CD16, HLA-DR, and CD8. In certain embodiments, it may be desirable to enrich for or positively select for regulatory T cells which typically express CD4+, CD25+, CD62Lhi, GITR+, and FoxP3+. Alternatively, in certain embodiments, T regulatory cells are depleted by anti-C25 conjugated beads or other similar method of selection.

For isolation of a desired population of cells by positive or negative selection, the concentration of cells and surface (e.g., particles such as beads) can be varied. In certain embodiments, it may be desirable to significantly decrease the volume in which beads and cells are mixed together (i.e., increase the concentration of cells) , to ensure maximum contact of cells and beads. For example, in one embodiment, a concentration of 2 billion cells/ml is used. In one embodiment, a concentration of 1 billion cells/ml is used. In a further embodiment, greater than 100 million cells/ml is used. In a further embodiment, a concentration of cells of 10, 15, 20, 25, 30, 35, 40, 45, or 50 million cells/ml is used. In yet another embodiment, a concentration of cells from 75, 80, 85, 90, 95, or 100 million cells/ml is used. In further embodiments, concentrations of 125 or 150 million cells/ml can be used. Using high concentrations may result in increased cell yield, cell activation, and cell expansion. Further, use of high cell concentrations may allow more efficient capture of cells that may weakly express target antigens of interest, such as CD28-negative T cells, or from samples where there are many tumor cells present (i.e., leukemic blood, tumor tissue, etc. ) . Such populations of cells may have therapeutic value and would be desirable to obtain. In some embodiments, using high concentration of cells allows more efficient selection of CD8+ T cells that normally have weaker CD28 expression.

In some embodiments, it may be desirable to use lower concentrations of cells. By significantly diluting the mixture of T cells and surface (e.g., particles such as beads) , interactions between the particles and cells is minimized. This selects for cells that express high amounts of desired antigens to be bound to the particles. For example, CD4+ T cells express higher levels of CD28 and are more efficiently captured than CD8+ T cells in dilute concentrations. In some embodiments, the concentration of cells used is 5×10 ⁶/ml. In some embodiments, the concentration used can be from about 1×10 ⁵/ml to 1×10 ⁶/ml, and any integer value in between.

In some embodiments, the cells may be incubated on a rotator for varying lengths of time at varying speeds at either 2-10℃, or at room temperature.

T cells for stimulation can also be frozen after a washing step. Without being bound by theory, the freeze and subsequent thaw step may provide a more uniform product by removing granulocytes and to some extent monocytes in the cell population. After the washing step that removes plasma and platelets, the cells may be suspended in a freezing solution. While many freezing solutions and parameters are known in the art and will be useful in this context, one method involves using PBS containing 20%DMSO and 8%human serum albumin, or culture media containing 10

%dextran

40 and 5%dextrose, 20%human serum albumin and 7.5% DMSO, or 31.25%plasmalyte-A, 31.25%dextrose 5%, 0.45%NaCl, 10

%dextran

40 and 5%dextrose, 20%human serum albumin, and 7.5%DMSO or other suitable cell freezing media containing for example, Hespan and PlasmaLyte A. The cells then are frozen to -80℃ at a rate of 1° per minute and stored in the vapor phase of a liquid nitrogen storage tank. Other methods of controlled freezing may be used as well as uncontrolled freezing immediately at -20℃ or in liquid nitrogen.

In some embodiments, cryopreserved cells are thawed and washed as described herein and allowed to rest for one hour at room temperature prior to activation.

Also contemplated in the present disclosure is the collection of blood samples or apheresis product from a subject at a time period prior to when the expanded cells as described herein might be needed. As such, the source of the cells to be expanded can be collected at any time point necessary, and desired cells, such as T cells, isolated and frozen for later use in T cell therapy for any number of diseases or conditions that would benefit from T cell therapy, such as those described herein. In one embodiment, a blood sample or an apheresis is taken from a generally healthy subject. In certain embodiments, a blood sample or an apheresis is taken from a generally healthy subject who is at risk of developing a disease, but who has not yet developed a disease, and the cells of interest are isolated and frozen for later use. In certain embodiments, the T cells may be expanded, frozen, and used at a later time. In certain embodiments, samples are collected from a patient shortly after diagnosis of a particular disease as described herein but prior to any treatments. In a further embodiment, the cells are isolated from a blood sample or an apheresis from a subject prior to any number of relevant treatment modalities, including but not limited to treatment with agents such as natalizumab, efalizumab, antiviral agents, chemotherapy, radiation, immunosuppressive agents, such as cyclosporin, azathioprine, methotrexate, mycophenolate, and FK506, antibodies, or other immunoablative agents such as CAMPATH, anti-CD3 antibodies, cytoxan, fludarabine, cyclosporin, FK506, rapamycin, mycophenolic acid, steroids, FR901228, and irradiation. These drugs inhibit either the calcium dependent phosphatase calcineurin (cyclosporine and FK506) or inhibit the p70S6 kinase that is important for growth factor induced signaling (rapamycin) (Liu et al., Cell 66: 807-815 (1991) ; Henderson et al., Immun 73: 316-321 (1991) ; Bierer et al., Curr. Opin. Immun. 5: 763-773 (1993) ) . In a further embodiment, the cells are isolated for a patient and frozen for later use in conjunction with (e.g., before, simultaneously or following) bone marrow or stem cell transplantation, T cell ablative therapy using either chemotherapy agents such as, fludarabine, external-beam radiation therapy (XRT) , cyclophosphamide, or antibodies such as OKT3 or CAMPATH. In another embodiment, the cells are isolated prior to and can be frozen for later use for treatment following B-cell ablative therapy such as agents that react with CD20, e.g., Rituxan.

In some embodiments, T cells are obtained from a patient directly following treatment. In this regard, it has been observed that following certain cancer treatments, in particular treatments with drugs that damage the immune system, shortly after treatment during the period when patients would normally be recovering from the treatment, the quality of T cells obtained may be optimal or improved for their ability to expand ex vivo. Likewise, following ex vivo manipulation using the methods described herein, these cells may be in a preferred state for enhanced engraftment and in vivo expansion. Thus, it is contemplated within the context of the present disclosure to collect blood cells, including T cells, dendritic cells, or other cells of the hematopoietic lineage, during this recovery phase. Further, in certain embodiments, mobilization (for example, mobilization with GM-CSF) and conditioning regimens can be used to create a condition in a subject wherein repopulation, recirculation, regeneration, and/or expansion of particular cell types is favored, especially during a defined window of time following therapy. Illustrative cell types include T cells, B cells, dendritic cells, and other cells of the immune system.

Activation and Expansion of T Cells

In some embodiments, prior to or after genetic modification of the T cells with the polypeptides described herein, the T cells can be activated and expanded generally using methods as described, for example, in U.S. Pat. Nos. 6,352,694; 6,534,055; 6,905,680; 6,692,964; 5,858,358; 6,887,466; 6,905,681; 7,144,575; 7,067,318; 7,172,869; 7,232,566; 7,175,843; 5,883,223; 6,905,874; 6,797,514; 6,867,041; and U.S. Patent Application Publication No. 20060121005.

Generally, T cells can be expanded by contact with a surface having attached thereto an agent that stimulates a CD3/TCR complex associated signal and a ligand that stimulates a co-stimulatory molecule on the surface of the T cells. In particular, T cell populations may be stimulated as described herein, such as by contact with an anti-CD3 antibody, or antigen-binding fragment thereof, or an anti-CD2 antibody immobilized on a surface, or by contact with a protein kinase C activator (e.g., bryostatin) in conjunction with a calcium ionophore. For co-stimulation of an accessory molecule on the surface of the T cells, a ligand that binds the accessory molecule is used. For example, a population of T cells can be contacted with an anti-CD3 antibody and an anti-CD28 antibody, under conditions appropriate for stimulating proliferation of the T cells. To stimulate proliferation of either CD4+ T cells or CD8+ T cells, an anti-CD3 antibody and an anti-CD28 antibody. Examples of an anti-CD3 antibody include UCHT1, OKT3, HIT3a (BioLegend, San Diego, US) can be used as can other methods commonly known in the art (Graves J, et al., J. Immunol. 146: 2102 (1991) ; Li B, et al., Immunology 116: 487 (2005) ; Rivollier A, et al., Blood 104: 4029 (2004) ) . Examples of an anti-CD28 antibody include 9.3, B-T3, XR-CD28 (Diaclone, Besancon, France) can be used as can other methods commonly known in the art (Berg et al., Transplant Proc. 30 (8) : 3975-3977 (1998) ; Haanen et al., J. Exp. Med. 190 (9) : 13191328 (1999) ; Garland et al., J. Immunol Meth. 227 (1-2) : 53-63 (1999) ) .

In some embodiments, the primary stimulatory signal and the co-stimulatory signal for the T cell may be provided by different protocols. For example, the agents providing each signal may be in solution or coupled to a surface. When coupled to a surface, the agents may be coupled to the same surface (i.e., in “cis” formation) or to separate surfaces (i.e., in “trans” formation) . Alternatively, one agent may be coupled to a surface and the other agent in solution. In one embodiment, the agent providing the co-stimulatory signal is bound to a cell surface and the agent providing the primary activation signal is in solution or coupled to a surface. In certain embodiments, both agents can be in solution. In another embodiment, the agents may be in soluble form, and then cross-linked to a surface, such as a cell expressing Fc receptors or an antibody or other binding agent which will bind to the agents. In this regard, see for example, U.S. Patent Application Publication Nos. 20040101519 and 20060034810 for artificial antigen presenting cells (aAPCs) that are contemplated for use in activating and expanding T cells in certain embodiments in the present disclosure.

In some embodiments, the T cells, are combined with agent-coated beads, the beads and the cells are subsequently separated, and then the cells are cultured. In an alternative embodiment, prior to culture, the agent-coated beads and cells are not separated but are cultured together. In a further embodiment, the beads and cells are first concentrated by application of a force, such as a magnetic force, resulting in increased ligation of cell surface markers, thereby inducing cell stimulation.

By way of example, cell surface proteins may be ligated by allowing paramagnetic beads to which anti-CD3 and anti-CD28 are attached (3×28 beads) to contact the T cells. In one embodiment, the cells (for example, 10 ⁴ to 4×10 ⁸ T cells) and beads (for example, anti-CD3/CD28 MACSiBead particlesa at a recommended titer of 1: 100) are combined in a buffer, preferably PBS (without divalent cations such as, calcium and magnesium) . Those of ordinary skill in the art can readily appreciate any cell concentration may be used. For example, the target cell may be very rare in the sample and comprise only 0.01%of the sample or the entire sample (i.e., 100%) may comprise the target cell of interest. Accordingly, any cell number is within the context of the present disclosure. In certain embodiments, it may be desirable to significantly decrease the volume in which particles and cells are mixed together (i.e., increase the concentration of cells) , to ensure maximum contact of cells and particles. For example, in one embodiment, a concentration of about 2 billion cells/mL is used. In another embodiment, greater than 100 million cells/mL is used. In a further embodiment, a concentration of cells of 10, 15, 20, 25, 30, 35, 40, 45, or 50 million cells/mL is used. In yet another embodiment, a concentration of cells from 75, 80, 85, 90, 95, or 100 million cells/mL is used. In further embodiments, concentrations of 125 or 150 million cells/mL can be used. Using high concentrations may result in increased cell yield, cell activation, and cell expansion. Further, use of high cell concentrations may allow more efficient capture of cells that may weakly express target antigens of interest, such as CD28-negative T cells. Such populations of cells may have therapeutic value and would be desirable to obtain in certain embodiments. For example, using high concentration of cells allows more efficient selection of CD8+ T cells that normally have weaker CD28 expression.

In some embodiments, the mixture may be cultured for several hours (about 3 hours) to about 14 days or any hourly integer value in between. In another embodiment, the mixture may be cultured for 21 days. In one embodiment, the beads and the T cells are cultured together for about eight days. In another embodiment, the beads and T cells are cultured together for 2-3 days. Several cycles of stimulation may also be desired such that culture time of T cells can be 60 days or more. Conditions appropriate for T cell culture include an appropriate media (e.g., Minimal Essential Media or RPMI Media 1640 or, X-vivo 15 (Lonza) ) that may contain factors necessary for proliferation and viability, including serum (e.g., fetal bovine or human serum) , interleukin-2 (IL-2) , insulin, IFN-γ, IL-4, IL-7, GM-CSF, IL-10, IL-12, IL-15, TGFβ, and TNF-αor any other additives for the growth of cells known to the skilled artisan. Other additives for the growth of cells include, but are not limited to, surfactant, plasmanate, and reducing agents such as N-acetyl-cysteine and 2-mercaptoethanol. Media can include RPMI 1640, AIM-V, DMEM, MEM, α-MEM, F-12, X-Vivo 15, and X-Vivo 20, optimizer, with added amino acids, sodium pyruvate, and vitamins, either serum-free or supplemented with an appropriate amount of serum (or plasma) or a defined set of hormones, and/or an amount of cytokine (s) sufficient for the growth and expansion of T cells. Antibiotics, e.g., penicillin and streptomycin, are included only in experimental cultures, not in cultures of cells that are to be infused into a subject. The target cells are maintained under conditions necessary to support growth, for example, an appropriate temperature (e.g., 37 ℃) and atmosphere (e.g., air plus 5%CO ₂) . T cells that have been exposed to varied stimulation times may exhibit different characteristics. For example, typical blood or apheresed peripheral blood mononuclear cell products have a helper T cell population (TH, CD4+) that is greater than the cytotoxic or suppressor T cell population (TC, CD8) . Ex vivo expansion of T cells by stimulating CD3 and CD28 receptors produces a population of T cells that prior to about days 8-9 consists predominately of TH cells, while after about days 8-9, the population of T cells comprises an increasingly greater population of TC cells. Accordingly, depending on the purpose of treatment, infusing a subject with a T cell population comprising predominately of TH cells may be advantageous. Similarly, if an antigen-specific subset of TC cells has been isolated it may be beneficial to expand this subset to a greater degree.

Further, in addition to CD4 and CD8 markers, other phenotypic markers vary significantly, but in large part, reproducibly during the course of the cell expansion process. Thus, such reproducibility enables the ability to tailor an activated T cell product for specific purposes.

5.3. Polypeptides

In another aspect, provided herein is a polypeptide comprising (a) a chimeric co-stimulatory receptor as described in Section 5.2.2; (b) a CAR as described in Section 5.2.1; and (c) a linker between the chimeric co-stimulatory receptor and the CAR.

In some embodiments, the second intracellular domain further comprises a third co-stimulatory domain. The chimeric co-stimulatory receptor may further comprises a first hinge region and the CAR may further comprises a second hinge region. In a preferred embodiment, the first hinge region is different from the second hinge region, and/or the first transmembrane domain is different from the second transmembrane domain, to ensure proper assembly of the two receptors on immune cells.

In some embodiments, the linker is a cleavable peptide linker. Any linkers that are cleavable in cells may be used in the present disclosure to link the CAR and the chimeric co-stimulatory receptor. In some embodiments, the peptide linker is a 2A self-cleaving peptide. The members of 2A peptides are named after the virus in which they have been first described. For example, F2A, the first described 2A peptide, is derived from foot-and-mouth disease virus. The self-cleaving 18-22 amino acids long 2A peptides mediate ‘ribosomal skipping’ between the proline and glycine residues and inhibit peptide bond formation without affecting downstream translation. These peptides allow multiple proteins to be encoded as polyproteins, which dissociate into component proteins upon translation. Self-cleaving peptides are found in members of the picornaviridae virus family, including aphthoviruses such as foot-and-mouth disease virus (FMDV) , equine rhinitis A virus (ERAV) , thosea asigna virus (TaV) and porcine teschovirus-1 (PTV-1) (see Donnelly et al., J. Gen. Virol., 82: 1027-101 (2001) ; Ryan et al., J. Gen. Virol., 72: 2727-2732 (2001) ) and cardioviruses such as theilovirus (e.g., theiler's murine encephalomyelitis) and encephalomyocarditis viruses. The 2A peptides derived from FMDV, ERAV, PTV-1, and TaV are sometimes referred to as “F2A, ” “E2A, ” “P2A, ” and “T2A, ” respectively, and are included in the present disclosure, e.g., as described in Donnelly et al., J. Gen. Virol., 78: 13-21 (1997) ; Ryan and Drew, EMBO J., 13: 928-933 (1994) ; Szymczak et al., Nature Biotech., 5: 589-594 (2004) ; Hasegawa et al., Stem Cells, 25 (7) : 1707-12 (2007) . In yet other embodiments, intein mediated protein splicing system is used herein, e.g., as described in Shah and Muir, Chem Sci., 5 (1) : 446–461 (2014) and Topilina and Mills, Mobile DNA, 5 (5) (2014) . Other methods known in the art can also be used in the present constructs.

In some embodiments, the 2A self-cleaving peptide is selected from a group consisting of F2A, E2A, P2A, T2A, or variants thereof. In some embodiments, the 2A self-cleaving peptide is a P2A peptide comprising an amino acid sequence of SEQ ID NO: 14. In some embodiments, the 2A self-cleaving peptide is a T2A peptide comprising an amino acid sequence of SEQ ID NO: 33.

5.4. Polynucleotides

In another aspect, the disclosure provides polynucleotides that encode the polypeptide provided herein, including those described in Section 5.2 and Section 5.3 above.

Also provided herein, in some embodiments, are compositions comprising one or more polynucleotides comprising a region encoding a CAR provided herein and a region encoding a chimeric co-stimulatory receptor provided herein, each of which is described above, e.g., in Section 5.2.1 and Section 5.2.2.

In some embodiments, provided herein is a polynucleotide encoding a polypeptide comprising (a) a chimeric co-stimulatory receptor as described in Section 5.2.2; (b) a CAR as described in Section 5.2.1; and (c) a peptide linker between the chimeric co-stimulatory receptor and the CAR. In some embodiments, the peptide linker is a 2A self-cleaving peptide. In some embodiments, the 2A self-cleaving peptide is selected from a group consisting of F2A, E2A, P2A, T2A, or variants thereof. In some embodiments, the 2A self-cleaving peptide is a P2A peptide comprising an amino acid sequence of SEQ ID NO: 14. In some embodiments, the 2A self-cleaving peptide is a T2A peptide comprising an amino acid sequence of SEQ ID NO: 33.

In other embodiments, provided herein is a polynucleotide comprising a first region encoding a polypeptide comprising a chimeric co-stimulatory receptor as described in Section 5.2.2; a second region encoding a CAR as described in Section 5.2.1. In some embodiments, the first region and the second region are controlled by the same promoter. For example, in some embodiments, internal ribosomal entry sites (IRES) are used herein to express multiple genes from one promoter. In other embodiments, the first region and the second region are controlled by separate promoters.

In yet other embodiments, provided herein is composition comprising a first polynucleotide encoding a polypeptide comprising a chimeric co-stimulatory receptor as described in Section 5.2.2; a second polynucleotide encoding a CAR as described in Section 5.2.1.

The polynucleotides of the disclosure can be in the form of RNA or in the form of DNA. DNA includes cDNA, genomic DNA, and synthetic DNA; and can be double-stranded or single-stranded, and if single stranded can be the coding strand or non-coding (anti-sense) strand. In some embodiments, the polynucleotide is in the form of cDNA. In some embodiments, the polynucleotide is a synthetic polynucleotide.

The present disclosure further relates to variants of the polynucleotides described herein, wherein the variant encodes, for example, fragments, analogs, and/or derivatives of the polypeptide of the disclosure. In certain embodiments, the present disclosure provides a polynucleotide comprising a polynucleotide having a nucleotide sequence at least about 75%identical, at least about 80%identical, at least about 85%identical, at least about 90%identical, at least about 95%identical, and in some embodiments, at least about 96%, 97%, 98%or 99%identical to a polynucleotide encoding the polypeptide of the disclosure. As used herein, the phrase “a polynucleotide having a nucleotide sequence at least, for example, 95% ‘identical’ to a reference nucleotide sequence” is intended to mean that the nucleotide sequence of the polynucleotide is identical to the reference sequence except that the polynucleotide sequence can include up to five point mutations per each 100 nucleotides of the reference nucleotide sequence. In other words, to obtain a polynucleotide having a nucleotide sequence at least 95%identical to a reference nucleotide sequence, up to 5%of the nucleotides in the reference sequence can be deleted or substituted with another nucleotide, or a number of nucleotides up to 5%of the total nucleotides in the reference sequence can be inserted into the reference sequence. These mutations of the reference sequence can occur at the 5’ or 3’ terminal positions of the reference nucleotide sequence or anywhere between those terminal positions, interspersed either individually among nucleotides in the reference sequence or in one or more contiguous groups within the reference sequence.

The polynucleotide variants can contain alterations in the coding regions, non-coding regions, or both. In some embodiments, a polynucleotide variant contains alterations which produce silent substitutions, additions, or deletions, but does not alter the properties or activities of the encoded polypeptide. In some embodiments, a polynucleotide variant comprises silent substitutions that results in no change to the amino acid sequence of the polypeptide (due to the degeneracy of the genetic code) . Polynucleotide variants can be produced for a variety of reasons, for example, to optimize codon expression for a particular host (i.e., change codons in the human mRNA to those preferred by a bacterial host such as E. coli) . In some embodiments, a polynucleotide variant comprises at least one silent mutation in a non-coding or a coding region of the sequence.

In some embodiments, a polynucleotide variant is produced to modulate or alter expression (or expression levels) of the encoded polypeptide. In some embodiments, a polynucleotide variant is produced to increase expression of the encoded polypeptide. In some embodiments, a polynucleotide variant is produced to decrease expression of the encoded polypeptide. In some embodiments, a polynucleotide variant has increased expression of the encoded polypeptide as compared to a parental polynucleotide sequence. In some embodiments, a polynucleotide variant has decreased expression of the encoded polypeptide as compared to a parental polynucleotide sequence.

5.5. Vectors

Also provided are vectors comprising the polynucleotides or nucleic acid molecules described herein. In one embodiment, the nucleic acid molecules can be incorporated into a recombinant expression vector.

The present disclosure provides vectors for cloning and expressing any one of the polypeptides described herein. In some embodiments, the vector is suitable for replication and integration in eukaryotic cells, such as mammalian cells. In some embodiments, the vector is a viral vector. Examples of viral vectors include, but are not limited to, adenoviral vectors, adeno-associated virus vectors, lentiviral vector, retroviral vectors, vaccinia vector, herpes simplex viral vector, and derivatives thereof. Viral vector technology is well known in the art and is described, for example, in Sambrook et al. (2001, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, New York) , and in other virology and molecular biology manuals.

A number of viral based systems have been developed for gene transfer into mammalian cells. For example, retroviruses provide a convenient platform for gene delivery systems. The heterologous nucleic acid can be inserted into a vector and packaged in retroviral particles using techniques known in the art. The recombinant virus can then be isolated and delivered to the engineered mammalian cell in vitro or ex vivo. A number of retroviral systems are known in the art. In some embodiments, adenovirus vectors are used. A number of adenovirus vectors are known in the art. In some embodiments, lentivirus vectors are used. In some embodiments, self-inactivating lentiviral vectors are used. For example, self-inactivating lentiviral vectors carrying the immunomodulator (such as immune checkpoint inhibitor) coding sequence and/or self-inactivating lentiviral vectors carrying chimeric antigen receptors can be packaged with protocols known in the art. The resulting lentiviral vectors can be used to transduce a mammalian cell (such as primary human T cells) using methods known in the art. Vectors derived from retroviruses such as lentivirus are suitable tools to achieve long-term gene transfer, because they allow long-term, stable integration of a transgene and its propagation in progeny cells. Lentiviral vectors also have low immunogenicity, and can transduce non-proliferating cells.

In some embodiments, the vector comprises any one of the nucleic acids encoding a polypeptide described herein. The nucleic acid can be cloned into the vector using any known molecular cloning methods in the art, including, for example, using restriction endonuclease sites and one or more selectable markers. In some embodiments, the nucleic acid is operably linked to a promoter. Varieties of promoters have been explored for gene expression in mammalian cells, and any of the promoters known in the art may be used in the present disclosure. Promoters may be roughly categorized as constitutive promoters or regulated promoters, such as inducible promoters.

In some embodiments, the nucleic acid encoding the polypeptide is operably linked to a constitutive promoter. Constitutive promoters allow heterologous genes (also referred to as transgenes) to be expressed constitutively in the host cells. Exemplary constitutive promoters contemplated herein include, but are not limited to, Cytomegalovirus (CMV) promoters, human elongation factors-1 alpha (hEF1α) , ubiquitin C promoter (UbiC) , phosphoglycerokinase promoter (PGK) , simian virus 40 early promoter (SV40) , and chicken β-Actin promoter coupled with CMV early enhancer (CAGG) . The efficiencies of such constitutive promoters on driving transgene expression have been widely compared in a huge number of studies. For example, Michael C. Milone et al compared the efficiencies of CMV, hEF1α, UbiC and PGK to drive chimeric antigen receptor expression in primary human T cells, and concluded that hEF1αpromoter not only induced the highest level of transgene expression, but was also optimally maintained in the CD4 and CD8 human T cells (Molecular Therapy, 17 (8) : 1453-1464 (2009) ) . In some embodiments, the nucleic acid encoding the CAR is operably linked to a hEF1αpromoter.

In some embodiments, the nucleic acid encoding the polypeptide is operably linked to an inducible promoter. Inducible promoters belong to the category of regulated promoters. The inducible promoter can be induced by one or more conditions, such as a physical condition, microenvironment of the engineered immune effector cell, or the physiological state of the engineered immune effector cell, an inducer (i.e., an inducing agent) , or a combination thereof.

In some embodiments, the inducing condition does not induce the expression of endogenous genes in the engineered mammalian cell, and/or in the subject that receives the pharmaceutical composition. In some embodiments, the inducing condition is selected from the group consisting of: inducer, irradiation (such as ionizing radiation, light) , temperature (such as heat) , redox state, tumor environment, and the activation state of the engineered mammalian cell.

In some embodiments, the vector also contains a selectable marker gene or a reporter gene to select cells expressing the polypeptide from the population of host cells transfected through lentiviral vectors. Both selectable markers and reporter genes may be flanked by appropriate regulatory sequences to enable expression in the host cells. For example, the vector may contain transcription and translation terminators, initiation sequences, and promoters useful for regulation of the expression of the nucleic acid sequences.

5.6. Methods of Making

In yet another aspect, provided herein is a method for making an engineered immune effector cell (e.g., a CAR-T cell or a TCR-T cell) , comprising introducing the polynucleotide or the vector provided herein (e.g., as described in Section 5.4 and Section 5.5 above) into an immune effector cell (e.g., a T cell) .

For example, in some embodiments, provided herein is a method for making a CAR-T cell, comprising introducing into a T cell a composition comprising one or more polynucleotides comprising a region encoding a CAR provided herein and a region encoding a chimeric co-stimulatory receptor provided herein, each of which is described above, e.g., in Section 5.2.1 and Section 5.2.2.

In some embodiments, provided herein is a method for making a CAR-T cell, comprising introducing into a T cell a polynucleotide encoding a polypeptide comprising (a) a chimeric co-stimulatory receptor as described in Section 5.2.2; (b) a CAR as described in Section 5.2.1; and (c) a peptide linker between the chimeric co-stimulatory receptor and the CAR. In some embodiments, the peptide linker is a 2A self-cleaving peptide. In some embodiments, the 2A self-cleaving peptide is selected from a group consisting of F2A, E2A, P2A, T2A, or variants thereof. In some embodiments, the 2A self-cleaving peptide is a P2A peptide comprising an amino acid sequence of SEQ ID NO: 14. In some embodiments, the 2A self-cleaving peptide is a T2A peptide comprising an amino acid sequence of SEQ ID NO: 33.

In other embodiments, provided herein is a method for making a CAR-T cell, comprising introducing into a T cell a polynucleotide comprising a first region encoding a polypeptide comprising a chimeric co-stimulatory receptor as described in Section 5.2.2; a second region encoding a CAR as described in Section 5.2.1. In some embodiments, the first region and the second region are controlled by the same promoter. For example, in some embodiments, internal ribosomal entry sites (IRES) are used herein to express multiple genes from one promoter. In other embodiments, the first region and the second region are controlled by separate promoters.

In yet other embodiments, provided herein is a method for making a CAR-T cell, comprising introducing into a T cell a first polynucleotide encoding a polypeptide comprising a chimeric co-stimulatory receptor as described in Section 5.2.2; a second polynucleotide encoding a CAR as described in Section 5.2.1.

In yet another aspect, provided herein is an engineered immune effector cell (e.g., a CAR-T cell) produced according to the method provided herein.

5.7. Pharmaceutical Compositions

In one aspect, the present disclosure further provides pharmaceutical compositions comprising an engineered T cell of the present disclosure. In some embodiments, a pharmaceutical composition comprises a therapeutically effective amount of the engineered T cell of the present disclosure and a pharmaceutically acceptable excipient.

In a specific embodiment, the term “excipient” can also refer to a diluent, adjuvant (e.g., Freunds’ adjuvant (complete or incomplete) , carrier or vehicle. Pharmaceutical excipients can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid excipients. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsion, tablets, pills, capsules, powders, sustained-release formulations and the like. Examples of suitable pharmaceutical excipients are described in Remington’s Pharmaceutical Sciences (1990) Mack Publishing Co., Easton, PA. Such compositions will contain a prophylactically or therapeutically effective amount of the active ingredient provided herein, such as in purified form, together with a suitable amount of excipient so as to provide the form for proper administration to the patient. The formulation should suit the mode of administration.

In some embodiments, the choice of excipient is determined in part by the particular cell, and/or by the method of administration. Accordingly, there are a variety of suitable formulations.

Typically, acceptable carriers, excipients, or stabilizers are nontoxic to recipients at the dosages and concentrations employed, and include buffers, antioxidants including ascorbic acid, methionine, Vitamin E, sodium metabisulfite; preservatives, isotonicifiers, stabilizers, metal complexes (e.g. Zn-protein complexes) ; chelating agents such as EDTA and/or non-ionic surfactants.

Buffers may be used to control the pH in a range which optimizes the therapeutic effectiveness, especially if stability is pH dependent. Suitable buffering agents for use with the present disclosure include both organic and inorganic acids and salts thereof. For example, citrate, phosphate, succinate, tartrate, fumarate, gluconate, oxalate, lactate, acetate. Additionally, buffers may comprise histidine and trimethylamine salts such as Tris.

Preservatives may be added to retard microbial growth. Suitable preservatives for use with the present disclosure include octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium halides (e.g., chloride, bromide, iodide) , benzethonium chloride; thimerosal, phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol, 3-pentanol, and m-cresol.

Tonicity agents, sometimes known as “stabilizers” can be present to adjust or maintain the tonicity of liquid in a composition. When used with large, charged biomolecules such as proteins and antibodies, they are often termed “stabilizers” because they can interact with the charged groups of the amino acid side chains, thereby lessening the potential for inter and intra-molecular interactions. Exemplary tonicity agents include polyhydric sugar alcohols, trihydric or higher sugar alcohols, such as glycerin, erythritol, arabitol, xylitol, sorbitol and mannitol.

Additional exemplary excipients include: (1) bulking agents, (2) solubility enhancers, (3) stabilizers and (4) agents preventing denaturation or adherence to the container wall. Such excipients include: polyhydric sugar alcohols (enumerated above) ; amino acids such as alanine, glycine, glutamine, asparagine, histidine, arginine, lysine, ornithine, leucine, 2-phenylalanine, glutamic acid, threonine, etc.; organic sugars or sugar alcohols such as sucrose, lactose, lactitol, trehalose, stachyose, mannose, sorbose, xylose, ribose, ribitol, myoinisitose, myoinisitol, galactose, galactitol, glycerol, cyclitols (e.g., inositol) , polyethylene glycol; sulfur containing reducing agents, such as urea, glutathione, thioctic acid, sodium thioglycolate, thioglycerol, α-monothioglycerol and sodium thio sulfate; low molecular weight proteins such as human serum albumin, bovine serum albumin, gelatin or other immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; monosaccharides (e.g., xylose, mannose, fructose, glucose; disaccharides (e.g., lactose, maltose, sucrose) ; trisaccharides such as raffinose; and polysaccharides such as dextrin or dextran.

Non-ionic surfactants or detergents (also known as “wetting agents” ) may be present to help solubilize the therapeutic agent as well as to protect the therapeutic protein against agitation-induced aggregation, which also permits the formulation to be exposed to shear surface stress without causing denaturation of the active therapeutic protein or antibody. Suitable non-ionic surfactants include, e.g., polysorbates (20, 40, 60, 65, 80, etc. ) , polyoxamers (184, 188, etc. ) ,

polyols,

polyoxyethylene sorbitan monoethers (

etc. ) , lauromacrogol 400, polyoxyl 40 stearate, polyoxyethylene hydrogenated

castor oil

10, 50 and 60, glycerol monostearate, sucrose fatty acid ester, methyl celluose and carboxymethyl cellulose. Anionic detergents that can be used include sodium lauryl sulfate, dioctyle sodium sulfosuccinate and dioctyl sodium sulfonate. Cationic detergents include benzalkonium chloride or benzethonium chloride.

The route of administration is in accordance with known and accepted methods, such as by single or multiple bolus or infusion over a long period of time in a suitable manner, e.g., injection or infusion by subcutaneous, intravenous, intraperitoneal, intramuscular, intraarterial, intralesional or intraarticular routes, topical administration, inhalation or by sustained release or extended-release means.

In another embodiment, a pharmaceutical composition can be provided as a controlled release or sustained release system. In one embodiment, a pump may be used to achieve controlled or sustained release (see, e.g., Sefton, Crit. Ref. Biomed. Eng. 14: 201-40 (1987) ; Buchwald et al., Surgery 88: 507-16 (1980) ; and Saudek et al., N. Engl. J. Med. 321: 569-74 (1989) ) . In another embodiment, polymeric materials can be used to achieve controlled or sustained release of a prophylactic or therapeutic agent (e.g., a fusion protein as described herein) or a composition provided herein (see, e.g., Medical Applications of Controlled Release (Langer and Wise eds., 1974) ; Controlled Drug Bioavailability, Drug Product Design and Performance (Smolen and Ball eds., 1984) ; Ranger and Peppas, J. Macromol. Sci. Rev. Macromol. Chem. 23: 61-126 (1983) ; Levy et al., Science 228: 190-92 (1985) ; During et al., Ann. Neurol. 25: 351-56 (1989) ; Howard et al., J. Neurosurg. 71: 105-12 (1989) ; U.S. Pat. Nos. 5,679,377; 5,916,597; 5,912,015; 5,989,463; and 5,128,326; PCT Publication Nos. WO 99/15154 and WO 99/20253) . Examples of polymers used in sustained release formulations include, but are not limited to, poly (2-hydroxy ethyl methacrylate) , poly (methyl methacrylate) , poly (acrylic acid) , poly (ethylene-co-vinyl acetate) , poly (methacrylic acid) , polyglycolides (PLG) , polyanhydrides, poly (N-vinyl pyrrolidone) , poly (vinyl alcohol) , polyacrylamide, poly (ethylene glycol) , polylactides (PLA) , poly (lactide-co-glycolides) (PLGA) , and polyorthoesters. In one embodiment, the polymer used in a sustained release formulation is inert, free of leachable impurities, stable on storage, sterile, and biodegradable. In yet another embodiment, a controlled or sustained release system can be placed in proximity of a particular target tissue, for example, the nasal passages or lungs, thus requiring only a fraction of the systemic dose (see, e.g., Goodson, Medical Applications of Controlled Release Vol. 2, 115-38 (1984) ) . Controlled release systems are discussed, for example, by Langer, Science 249: 1527-33 (1990) . Any technique known to one of skill in the art can be used to produce sustained release formulations comprising one or more agents as described herein (see, e.g., U.S. Pat. No. 4,526,938, PCT publication Nos. WO 91/05548 and WO 96/20698, Ning et al., Radiotherapy &Oncology 39: 179-89 (1996) ; Song et al., PDA J. of Pharma. Sci. &Tech. 50: 372-97 (1995) ; Cleek et al., Pro. Int’l. Symp. Control. Rel. Bioact. Mater. 24: 853-54 (1997) ; and Lam et al., Proc. Int’l. Symp. Control Rel. Bioact. Mater. 24: 759-60 (1997) ) .

The pharmaceutical compositions described herein may also contain more than one active compound or agent as necessary for the particular indication being treated. Alternatively, or in addition, the composition may comprise a cytotoxic agent, chemotherapeutic agent, cytokine, immunosuppressive agent, or growth inhibitory agent. Such molecules are suitably present in combination in amounts that are effective for the purpose intended.

The active ingredients may also be entrapped in microcapsules prepared, for example, by coascervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsules and poly- (methylmethacylate) microcapsules, respectively, in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles and nanocapsules) or in macroemulsions. Such techniques are disclosed in Remington's Pharmaceutical Sciences 18th edition.

Various compositions and delivery systems are known and can be used with the therapeutic agents provided herein, including, but not limited to, encapsulation in liposomes, microparticles, microcapsules, recombinant cells capable of expressing the single domain antibody or therapeutic molecule provided herein, construction of a nucleic acid as part of a retroviral or other vector, etc.

In some embodiments, the pharmaceutical composition provided herein contains the binding molecules and/or cells in amounts effective to treat or prevent the disease or disorder, such as a therapeutically effective or prophylactically effective amount. Therapeutic or prophylactic efficacy in some embodiments is monitored by periodic assessment of treated subjects. For repeated administrations over several days or longer, depending on the condition, the treatment is repeated until a desired suppression of disease symptoms occurs. However, other dosage regimens may be useful and can be determined.

5.8. Methods and Uses

In another aspect, provided herein are methods for using and uses of the engineered T cells provided herein. Such methods and uses include therapeutic methods and uses, for example, involving administration of the cells, or compositions containing the same, to a subject having a disease or disorder. In some embodiments, the cell is administered in an effective amount to effect treatment of the disease or disorder. Uses include uses of the cells in such methods and treatments, and in the preparation of a medicament in order to carry out such therapeutic methods. In some embodiments, the methods are carried out by administering the cells, or compositions comprising the same, to the subject having or suspected of having the disease or condition. In some embodiments, the methods thereby treat the disease or disorder in the subject.

In some embodiments, the treatment provided herein cause complete or partial amelioration or reduction of a disease or disorder, or a symptom, adverse effect or outcome, or phenotype associated therewith. Desirable effects of treatment include, but are not limited to, preventing occurrence or recurrence of disease, alleviation of symptoms, diminishment of any direct or indirect pathological consequences of the disease, preventing metastasis, decreasing the rate of disease progression, amelioration or palliation of the disease state, and remission or improved prognosis. The terms include, but do not imply, complete curing of a disease or complete elimination of any symptom or effect (s) on all symptoms or outcomes.

As used herein, in some embodiments, the treatment provided herein delay development of a disease or disorder, e.g., defer, hinder, slow, retard, stabilize, suppress and/or postpone development of the disease (such as cancer) . This delay can be of varying lengths of time, depending on the history of the disease and/or individual being treated. As is evident to one skilled in the art, a sufficient or significant delay can, in effect, encompass prevention, in that the individual does not develop the disease or disorder. For example, a late stage cancer, such as development of metastasis, may be delayed. In other embodiments, the method or the use provided herein prevents a disease or disorder.

In some embodiments, the present CAR-T cell therapies are used for treating solid tumor cancer. In other embodiments, the present CAR-T cell therapies are used for treating blood cancer. In other embodiments, the disease or disorder is an autoimmune and inflammatory disease.

In some embodiments, the disease or disorder is a disease of abnormal cell growth and/or dysregulated apoptosis. Examples of such diseases include, but are not limited to, cancer, mesothelioma, bladder cancer, pancreatic cancer, skin cancer, cancer of the head or neck, cutaneous or intraocular melanoma, ovarian cancer, breast cancer, uterine cancer, carcinoma of the fallopian tubes, carcinoma of the endometrium, carcinoma of the cervix, carcinoma of the vagina, carcinoma of the vulva, bone cancer, colon cancer, rectal cancer, cancer of the anal region, stomach cancer, gastrointestinal (gastric, colorectal and/or duodenal) cancer, chronic lymphocytic leukemia, acute lymphocytic leukemia, esophageal cancer, cancer of the small intestine, cancer of the endocrine system, cancer of the thyroid gland, cancer of the parathyroid gland, cancer of the adrenal gland, sarcoma of soft tissue, cancer of the urethra, cancer of the penis, testicular cancer, hepatocellular (hepatic and/or biliary duct) cancer, primary or secondary central nervous system tumor, primary or secondary brain tumor, Hodgkin's disease, chronic or acute leukemia, chronic myeloid leukemia, lymphocytic lymphoma, lymphoblastic leukemia, follicular lymphoma, lymphoid malignancies of T-cell or B-cell origin, melanoma, multiple myeloma, oral cancer, non-small-cell lung cancer, prostate cancer, small-cell lung cancer, cancer of the kidney and/or ureter, renal cell carcinoma, carcinoma of the renal pelvis, neoplasms of the central nervous system, primary central nervous system lymphoma, non-Hodgkin's lymphoma, spinal axis tumors, brain stem glioma, pituitary adenoma, adrenocortical cancer, gall bladder cancer, cancer of the spleen, cholangiocarcinoma, fibrosarcoma, neuroblastoma, retinoblastoma or a combination thereof.

In some embodiments, the disease or disorder is selected from the group consisting of bladder cancer, brain cancer, breast cancer, bone marrow cancer, cervical cancer, chronic lymphocytic leukemia, acute lymphocytic leukemia, colorectal cancer, esophageal cancer, hepatocellular cancer, lymphoblastic leukemia, follicular lymphoma, lymphoid malignancies of T-cell or B-cell origin, melanoma, myelogenous leukemia, myeloma, oral cancer, ovarian cancer, non-small-cell lung cancer, prostate cancer, small-cell lung cancer and spleen cancer.

In some embodiments, the disease or disorder is a hematological cancer, such as leukemia, lymphoma, or myeloma. In some embodiments, the cancer is selected from a group consisting of Hodgkin's lymphoma, non-Hodgkin's lymphoma (NHL) , cutaneous B-cell lymphoma, activated B-cell lymphoma, diffuse large B-cell lymphoma (DLBCL) , mantle cell lymphoma (MCL) , follicular center lymphoma, transformed lymphoma, lymphocytic lymphoma of intermediate differentiation, intermediate lymphocytic lymphoma (ILL) , diffuse poorly differentiated lymphocytic lymphoma (PDL) , centrocytic lymphoma, diffuse small-cleaved cell lymphoma (DSCCL) , peripheral T-cell lymphomas (PTCL) , cutaneous T-Cell lymphoma, mantle zone lymphoma, low grade follicular lymphoma, multiple myeloma (MM) , chronic lymphocytic leukemia (CLL) , diffuse large B-cell lymphoma (DLBCL) , myelodysplastic syndrome (MDS) , acute T cell leukemia, acute myeloid leukemia (AML) , acute promyelocytic leukemia, acute myeloblastic leukemia, acute megakaryoblastic leukemia, precursor B acute lymphoblastic leukemia, precursor T acute lymphoblastic leukemia, Burkitt’s leukemia (Burkitt’s lymphoma) , acute biphenotypic leukemia, chronic myeloid lymphoma, chronic myelogenous leukemia (CML) , and chronic monocytic leukemia. In a specific embodiment, the disease or disorder is myelodysplastic syndromes (MDS) . In another specific embodiment, the disease or disorder is acute myeloid leukemia (AML) . In another specific embodiment, the disease or disorder is chronic lymphocytic leukemia (CLL) . In yet another specific embodiment, the disease or disorder is multiple myeloma (MM) .

In other embodiments, the disease or disorder is a solid tumor cancer. In some embodiments, the solid tumor cancer is selected from a group consisting of a carcinoma, an adenocarcinoma, an adrenocortical carcinoma, a colon adenocarcinoma, a colorectal adenocarcinoma, a colorectal carcinoma, a ductal cell carcinoma, a lung carcinoma, a thyroid carcinoma, a nasopharyngeal carcinoma, a melanoma, a non-melanoma skin carcinoma, and a lung cancer.

In other embodiments, the disease or disorder is an immune or autoimmune disorder. Such disorders include autoimmune bullous disease, abetalipoprotemia, acquired immunodeficiency-related diseases, acute immune disease associated with organ transplantation, acquired acrocyanosis, acute and chronic parasitic or infectious processes, acute pancreatitis, acute renal failure, acute rheumatic fever, acute transverse myelitis, adenocarcinomas, aerial ectopic beats, adult (acute) respiratory distress syndrome, AIDS dementia complex, alcoholic cirrhosis, alcohol-induced liver injury, alcohol-induced hepatitis, allergic conjunctivitis, allergic contact dermatitis, allergic rhinitis, allergy and asthma, allograft rejection, alpha-l-antitrypsin deficiency, Alzheimer's disease, amyotrophic lateral sclerosis, anemia, angina pectoris, ankylosing spondylitis-associated lung disease, anterior horn cell degeneration, antibody mediated cytotoxicity, antiphospholipid syndrome, anti-receptor hypersensitivity reactions, aortic and peripheral aneurysms, aortic dissection, arterial hypertension, arteriosclerosis, arteriovenous fistula, arthropathy, asthenia, asthma, ataxia, atopic allergy, atrial fibrillation (sustained or paroxysmal) , atrial flutter, atrioventricular block, atrophic autoimmune hypothyroidism, autoimmune haemo lytic anaemia, autoimmune hepatitis, type-1 autoimmune hepatitis (classical autoimmune or lupoid hepatitis) , autoimmune mediated hypoglycemia, autoimmune neutropenia, autoimmune thrombocytopenia, autoimmune thyroid disease, B-cell lymphoma, bone graft rejection, bone marrow transplant (BMT) rejection, bronchiolitis obliterans, bundle branch block, burns, cachexia, cardiac arrhythmias, cardiac stun syndrome, cardiac tumors, cardiomyopathy, cardiopulmonary bypass inflammation response, cartilage transplant rejection, cerebellar cortical degenerations, cerebellar disorders, chaotic or multifocal atrial tachycardia, chemotherapy-associated disorders, chlamydia, choleosatatis, chronic alcoholism, chronic active hepatitis, chronic fatigue syndrome, chronic immune disease associated with organ transplantation, chronic eosinophilic pneumonia, chronic inflammatory pathologies, chronic mucocutaneous candidiasis, chronic obstructive pulmonary disease (COPD) , chronic salicylate intoxication, colorectal common varied immunodeficiency (common variable hypogammaglobulinemia) , conjunctivitis, connective tissue disease-associated interstitial lung disease, contact dermatitis, Coombs-positive hemolytic anemia, cor pulmonale, Creutzfeldt-Jakob disease, cryptogenic autoimmune hepatitis, cryptogenic fibrosing alveolitis, culture-negative sepsis, cystic fibrosis, cytokine therapy-associated disorders, Crohn's disease, dementia pugilistica, demyelinating diseases, dengue hemorrhagic fever, dermatitis, dermatitis scleroderma, dermatologic conditions, dermatomyositis/polymyositis-associated lung disease, diabetes, diabetic arteriosclerotic disease, diabetes mellitus, diffuse Lewy body disease, dilated cardiomyopathy, dilated congestive cardiomyopathy, discoid lupus erythematosus, disorders of the basal ganglia, disseminated intravascular coagulation, Down's Syndrome in middle age, drug-induced interstitial lung disease, drug-induced hepatitis, drug-induced movement disorders induced by drugs which block CNS dopamine receptors, drug sensitivity, eczema, encephalomyelitis, endocarditis, endocrinopathy, enteropathic synovitis, epiglottitis, Epstein-Barr virus infection, erythromelalgia, extrapyramidal and cerebellar disorders, familial hematophagocytic lymphohistiocytosis, fetal thymus implant rejection, Friedreich's ataxia, functional peripheral arterial disorders, female infertility, fibrosis, fibrotic lung disease, fungal sepsis, gas gangrene, gastric ulcer, giant cell arteritis, glomerular nephritis, glomerulonephritides, Goodpasture's syndrome, goitrous autoimmune hypothyroidism (Hashimoto's disease) , gouty arthritis, graft rejection of any organ or tissue, graft versus host disease, gram-negative sepsis, gram-positive sepsis, granulomas due to intracellular organisms, group B streptococci (GBS) infection, Graves' disease, hemosiderosis-associated lung disease, hairy cell leukemia, Hallerrorden-Spatz disease, Hashimoto's thyroiditis, hay fever, heart transplant rejection, hemachromatosis, hematopoietic malignancies (leukemia and lymphoma) , hemolytic anemia, hemolytic uremic syndrome/thrombolytic thrombocytopenic purpura, hemorrhage, Henoch-Schoenlein purpura, hepatitis A, hepatitis B, hepatitis C, HIV infection/HIV neuropathy, Hodgkin's disease, hypoparathyroidism, Huntington's chorea, hyperkinetic movement disorders, hypersensitivity reactions, hypersensitivity pneumonitis, hyperthyroidism, hypokinetic movement disorders, hypothalamic-pituitary-adrenal axis evaluation, idiopathic Addison's disease, idiopathic leucopenia, idiopathic pulmonary fibrosis, idiopathic thrombocytopenia, idiosyncratic liver disease, infantile spinal muscular atrophy, infectious diseases, inflammation of the aorta, inflammatory bowel disease, insulin dependent diabetes mellitus, interstitial pneumonitis, iridocyclitis/uveitis/optic neuritis, ischemia-reperfusion injury, ischemic stroke, juvenile pernicious anemia, juvenile rheumatoid arthritis, juvenile spinal muscular atrophy, Kaposi's sarcoma, Kawasaki's disease, kidney transplant rejection, legionella, leishmaniasis, leprosy, lesions of the corticospinal system, linear IgA disease, lipidema, liver transplant rejection, Lyme disease, lymphederma, lymphocytic infiltrative lung disease, malaria, male infertility idiopathic or NOS, malignant histiocytosis, malignant melanoma, meningitis, meningococcemia, microscopic vasculitis of the kidneys, migraine headache, mitochondrial multisystem disorder, mixed connective tissue disease, mixed connective tissue disease-associated lung disease, monoclonal gammopathy, multiple myeloma, multiple systems degenerations (Mencel, Dejerine-Thomas, Shy-Drager and Machado-Joseph) , myalgic encephalitis/Royal Free Disease, myasthenia gravis, microscopic vasculitis of the kidneys, mycobacterium avium intracellulare, mycobacterium tuberculosis, myelodyplastic syndrome, myocardial infarction, myocardial ischemic disorders, nasopharyngeal carcinoma, neonatal chronic lung disease, nephritis, nephrosis, nephrotic syndrome, neurodegenerative diseases, neurogenic I muscular atrophies, neutropenic fever, non-alcoholic steatohepatitis, occlusion of the abdominal aorta and its branches, occlusive arterial disorders, organ transplant rejection, orchitis/epidydimitis, orchitis/vasectomy reversal procedures, organomegaly, osteoarthrosis, osteoporosis, ovarian failure, pancreas transplant rejection, parasitic diseases, parathyroid transplant rejection, Parkinson's disease, pelvic inflammatory disease, pemphigus vulgaris, pemphigus foliaceus, pemphigoid, perennial rhinitis, pericardial disease, peripheral atherlosclerotic disease, peripheral vascular disorders, peritonitis, pernicious anemia, phacogenic uveitis, Pneumocystis carinii pneumonia, pneumonia, POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome) , post-perfusion syndrome, post-pump syndrome, post-MI cardiotomy syndrome, postinfectious interstitial lung disease, premature ovarian failure, primary biliary cirrhosis, primary sclerosing hepatitis, primary myxoedema, primary pulmonary hypertension, primary sclerosing cholangitis, primary vasculitis, progressive supranuclear palsy, psoriasis, psoriasis type 1, psoriasis type 2, psoriatic arthropathy, pulmonary hypertension secondary to connective tissue disease, pulmonary manifestation of polyarteritis nodosa, post-inflammatory interstitial lung disease, radiation fibrosis, radiation therapy, Raynaud's phenomenon and disease, Raynoud's disease, Refsum's disease, regular narrow QRS tachycardia, Reiter's disease, renal disease NOS, renovascular hypertension, reperfusion injury, restrictive cardiomyopathy, rheumatoid arthritis-associated interstitial lung disease, rheumatoid spondylitis, sarcoidosis, Schmidt's syndrome, scleroderma, senile chorea, senile dementia of Lewy body type, sepsis syndrome, septic shock, seronegative arthropathies, shock, sickle cell anemia, T-cell or FAB ALL, Takayasu's disease/arteritis, telangiectasia, Th2-type and Thl-type mediated diseases, thromboangitis obliterans, thrombocytopenia, thyroiditis, toxicity, toxic shock syndrome, transplants, trauma/hemorrhage, type-2 autoimmune hepatitis (anti-LKM antibody hepatitis) , type B insulin resistance with acanthosis nigricans, type III hypersensitivity reactions, type IV hypersensitivity, ulcerative colitic arthropathy, ulcerative colitis, unstable angina, uremia, urosepsis, urticaria, uveitis, valvular heart diseases, varicose veins, vasculitis, vasculitic diffuse lung disease, venous diseases, venous thrombosis, ventricular fibrillation, vitiligo acute liver disease, viral and fungal infections, vital encephalitis/aseptic meningitis, vital-associated hemaphagocytic syndrome, Wegener's granulomatosis, Wernicke-Korsakoff syndrome, Wilson's disease, xenograft rejection of any organ or tissue, yersinia and salmonella-associated arthropathy, acquired immunodeficiency disease syndrome (AIDS) , autoimmune lymphoproliferative syndrome, hemolytic anemia, inflammatory diseases, thrombocytopenia, acute and chronic immune diseases associated with organ transplantation, Addison's disease, allergic diseases, alopecia, alopecia areata, atheromatous disease/arteriosclerosis, atherosclerosis, arthritis (including osteoarthritis, juvenile chronic arthritis, septic arthritis, Lyme arthritis, psoriatic arthritis and reactive arthritis) , Sjogren's disease-associated lung disease, Sjogren's syndrome, skin allograft rejection, skin changes syndrome, small bowel transplant rejection, sperm autoimmunity, multiple sclerosis (all subtypes) , spinal ataxia, spinocerebellar degenerations, spondyloarthropathy, sporadic polyglandular deficiency type I, sporadic polyglandular deficiency type II, Still's disease, streptococcal myositis, stroke, structural lesions of the cerebellum, subacute sclerosing panencephalitis, sympathetic ophthalmia, syncope, syphilis of the cardiovascular system, systemic anaphylaxis, systemic inflammatory response syndrome, systemic onset juvenile rheumatoid arthritis, systemic lupus erythematosus, systemic lupus erythematosus-associated lung disease, lupus nephritis, systemic sclerosis, and systemic sclerosis-associated interstitial lung disease.

In some embodiments, the disease or disorder is an inflammatory disease. Inflammation plays a fundamental role in host defenses and the progression of immune-mediated diseases. The inflammatory response is initiated in response to injury (e.g., trauma, ischemia, and foreign particles) and infection (e.g., bacterial or viral infection) by a complex cascade of events, including chemical mediators (e.g., cytokines and prostaglandins) and inflammatory cells (e.g., leukocytes) . The inflammatory response is characterized by increased blood flow, increased capillary permeability, and the influx of phagocytic cells. These events result in swelling, redness, warmth (altered heat patterns) , and pus formation at the site of injury or infection.

Cytokines and prostaglandins control the inflammatory response, and are released in an ordered and self-limiting cascade into the blood or affected tissues. This release of cytokines and prostaglandins increases the blood flow to the area of injury or infection, and may result in redness and warmth. Some of these chemicals cause a leak of fluid into the tissues, resulting in swelling. This protective process may stimulate nerves and cause pain. These changes, when occurring for a limited period in the relevant area, work to the benefit of the body.

A delicate well-balanced interplay between the humoral and cellular immune elements in the inflammatory response enables the elimination of harmful agents and the initiation of the repair of damaged tissue. When this delicately balanced interplay is disrupted, the inflammatory response may result in considerable damage to normal tissue and may be more harmful than the original insult that initiated the reaction. In these cases of uncontrolled inflammatory responses, clinical intervention is needed to prevent tissue damage and organ dysfunction. Diseases such as psoriasis, rheumatoid arthritis, osteoarthritis, psoriatic arthritis, Crohn’s disease, asthma, allergies or inflammatory bowel disease, are characterized by chronic inflammation. Inflammatory diseases such as arthritis, related arthritic conditions (e.g., osteoarthritis, rheumatoid arthritis, and psoriatic arthritis) , inflammatory bowel disease (e.g., Crohn's disease and ulcerative colitis) , sepsis, psoriasis, atopic dermatitis, contact dermatitis, and chronic obstructive pulmonary disease, chronic inflammatory pulmonary diseases are also prevalent and problematic ailments.

In some embodiments, the methods include adoptive cell therapy, whereby genetically engineered cells are administered to a subject. Such administration can promote activation of the cells (e.g., T cell activation) , such that the cells of the disease or disorder are targeted for destruction.

In some embodiments, the methods include administration of the cells or a composition containing the cells to a subject, tissue, or cell, such as one having, at risk for, or suspected of having the disease or disorder. In some embodiments, the cells, populations, and compositions are administered to a subject having the particular disease or disorder to be treated, e.g., via adoptive cell therapy, such as adoptive T cell therapy. In some embodiments, the cells or compositions are administered to the subject, such as a subject having or at risk for the disease or disorder. In some embodiments, the methods thereby treat, e.g., ameliorate one or more symptom of the disease or disorder.

Methods for administration of cells for adoptive cell therapy are known, as described, e.g., in US Patent Application Publication No. 2003/0170238; U.S. Pat. No. 4,690,915; Rosenberg, Nat Rev Clin Oncol. 8 (10) : 577-85 (2011) ; Themeli et al., Nat Biotechnol. 31 (10) : 928-933 (2013) ; Tsukahara et al., Biochem Biophys Res Commun 438 (1) : 84-9 (2013) ; and Davila et al., PLoS ONE 8 (4) : e61338 (2013) . These methods may be used in connection with the methods and compositions provided herein.

In some embodiments, the cell therapy (e.g., adoptive T cell therapy) is carried out by autologous transfer, in which the cells are isolated and/or otherwise prepared from the subject who is to receive the cell therapy, or from a sample derived from such a subject. Thus, in some aspects, the cells are derived from a subject in need of a treatment and the cells, following isolation and processing are administered to the same subject. In other embodiments, the cell therapy (e.g., adoptive T cell therapy) is carried out by allogeneic transfer, in which the cells are isolated and/or otherwise prepared from a subject other than a subject who is to receive or who ultimately receives the cell therapy, e.g., a first subject. In such embodiments, the cells then are administered to a different subject, e.g., a second subject, of the same species. In some embodiments, the first and second subjects are genetically identical. In some embodiments, the first and second subjects are genetically similar. In some embodiments, the second subject expresses the same HLA class or supertype as the first subject.

In some embodiments, the subject, to whom the cells, cell populations, or compositions are administered is a primate, such as a human. The subject can be male or female and can be any suitable age, including infant, juvenile, adolescent, adult, and geriatric subjects. In some examples, the subject is a validated animal model for disease, adoptive cell therapy, and/or for assessing toxic outcomes.

The composition provided herein can be administered by any suitable means, for example, by injection, e.g., intravenous or subcutaneous injections, intraocular injection, periocular injection, subretinal injection, intravitreal injection, trans-septal injection, subscleral injection, intrachoroidal injection, intracameral injection, subconjectval injection, subconjuntival injection, sub-Tenon's injection, retrobulbar injection, peribulbar injection, or posterior juxtascleral delivery. In some embodiments, they are administered by parenteral, intrapulmonary, and intranasal, and, if desired for local treatment, intralesional administration. Parenteral infusions include intramuscular, intravenous, intraarterial, intraperitoneal, or subcutaneous administration.

The amount of a prophylactic or therapeutic agent provided herein that will be effective in the prevention and/or treatment of a disease or condition can be determined by standard clinical techniques. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal model test systems. For the prevention or treatment of disease, the appropriate dosage of the binding molecule or cell may depend on the type of disease or disorder to be treated, the type of binding molecule, the severity and course of the disease or disorder, whether the therapeutic agent is administered for preventive or therapeutic purposes, previous therapy, the patient's clinical history and response to the agent, and the discretion of the attending physician. The compositions, molecules and cells are in some embodiments suitably administered to the patient at one time or over a series of treatments. Multiple doses may be administered intermittently. An initial higher loading dose, followed by one or more lower doses may be administered.

In the context of genetically engineered cells, in some embodiments, a subject may be administered the range of about one million to about 100 billion cells and/or that amount of cells per kilogram of body weight. In some embodiments, wherein the pharmaceutical composition comprises any one of the engineered immune cells described herein, the pharmaceutical composition is administered at a dosage of at least about any of 10 ⁴, 10 ⁵, 10 ⁶, 10 ⁷, 10 ⁸, or 10 ⁹ cells/kg of body weight of the individual. Dosages may vary depending on attributes particular to the disease or disorder and/or patient and/or other treatments.

In some embodiments, the pharmaceutical composition is administered for a single time. In some embodiments, the pharmaceutical composition is administered for multiple times (such as any of 2, 3, 4, 5, 6, or more times) . In some embodiments, the pharmaceutical composition is administered once or multiple times during a dosing cycle. A dosing cycle can be, e.g., 1, 2, 3, 4, 5 or more week (s) , or 1, 2, 3, 4, 5, or more month (s) . The optimal dosage and treatment regime for a particular patient can be determined by one skilled in the art of medicine by monitoring the patient for signs of disease and adjusting the treatment accordingly.

In some embodiments, the compositions provided herein are administered as part of a combination treatment, such as simultaneously with or sequentially with, in any order, another therapeutic intervention, such as another antibody or engineered cell or receptor or agent, such as a cytotoxic or therapeutic agent.

In some embodiments, the compositions provided herein are co-administered with one or more additional therapeutic agents or in connection with another therapeutic intervention, either simultaneously or sequentially in any order. In some embodiments, the cells are co-administered with another therapy sufficiently close in time such that the cell populations enhance the effect of one or more additional therapeutic agents, or vice versa. In some embodiments, the compositions provided herein are administered prior to the one or more additional therapeutic agents. In some embodiments, the compositions provided herein are administered after to the one or more additional therapeutic agents.

In certain embodiments, once the cells are administered to a mammal (e.g., a human) , the biological activity of the engineered cell populations is measured by any of a number of known methods. Parameters to assess include specific binding of an engineered or natural T cell or other immune cell to antigen, in vivo, e.g., by imaging, or ex vivo, e.g., by ELISA or flow cytometry. In certain embodiments, the ability of the engineered cells to destroy target cells can be measured using any suitable method known in the art, such as cytotoxicity assays described in, for example, Kochenderfer et al., J. Immunotherapy, 32 (7) : 689-702 (2009) , and Herman et al. J. Immunological Methods, 285 (1) : 25-40 (2004) . In certain embodiments, the biological activity of the cells also can be measured by assaying expression and/or secretion of certain cytokines, such as CD107a, IFN-γ, IL-2, and TNF. In some aspects the biological activity is measured by assessing clinical outcome, such as reduction in tumor burden or load.

5.9. Kits and Articles of Manufacture

Further provided are kits, unit dosages, and articles of manufacture comprising any of the engineered immune effector cells described herein. In some embodiments, a kit is provided which contains any one of the pharmaceutical compositions described herein and preferably provides instructions for its use.

The kits of the present application are in suitable packaging. Suitable packaging includes, but is not limited to, vials, bottles, jars, flexible packaging (e.g., sealed Mylar or plastic bags) , and the like. Kits may optionally provide additional components such as buffers and interpretative information. The present application thus also provides articles of manufacture, which include vials (such as sealed vials) , bottles, jars, flexible packaging, and the like.

The article of manufacture can comprise a container and a label or package insert on or associated with the container. Suitable containers include, for example, bottles, vials, syringes, etc. The containers may be formed from a variety of materials such as glass or plastic. Generally, the container holds a composition which is effective for treating a disease or disorder (such as cancer) described herein, and may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle) . The label or package insert indicates that the composition is used for treating the particular condition in an individual. The label or package insert will further comprise instructions for administering the composition to the individual. The label may indicate directions for reconstitution and/or use. The container holding the pharmaceutical composition may be a multi-use vial, which allows for repeat administrations (e.g. from 2-6 administrations) of the reconstituted formulation. Package insert refers to instructions customarily included in commercial packages of therapeutic products that contain information about the indications, usage, dosage, administration, contraindications and/or warnings concerning the use of such therapeutic products. Additionally, the article of manufacture may further comprise a second container comprising a pharmaceutically-acceptable buffer, such as bacteriostatic water for injection (BWFI) , phosphate-buffered saline, Ringer's solution and dextrose solution. It may further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, and syringes.

The kits or article of manufacture may include multiple unit doses of the pharmaceutical composition and instructions for use, packaged in quantities sufficient for storage and use in pharmacies, for example, hospital pharmacies and compounding pharmacies.

The disclosure is generally disclosed herein using affirmative language to describe the numerous embodiments. The disclosure also specifically includes embodiments in which particular subject matter is excluded, in full or in part, such as substances or materials, method steps and conditions, protocols, procedures, assays or analysis. Thus, even though the disclosure is generally not expressed herein in terms of what the disclosure does not include, aspects that are not expressly included in the disclosure are nevertheless disclosed herein.

A number of embodiments of the disclosure have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, the following examples are intended to illustrate but not limit the scope of disclosure described in the claims.

6. EXAMPLES

The following is a description of various methods and materials used in the studies, and are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the present disclosure, and are not intended to limit the scope of what the inventors regard as their disclosure nor are they intended to represent that the experiments below were performed and are all of the experiments that may be performed. It is to be understood that exemplary descriptions written in the present tense were not necessarily performed, but rather that the descriptions can be performed to generate the data and the like associated with the teachings of the present disclosure. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, percentages, etc. ) , but some experimental errors and deviations should be accounted for.

6.1. Example 1-Generation of retroviral vectors

GPC2-BBz and GPC2-28z: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a GPC2-specific V _HH, a human CD8α stalk and transmembrane domain, followed by a 4-1BB endodomain for the GPC2-BBz or a human CD28 stalk and transmembrane domain CD28 endodomain for the GPC2-28z and the ζ-chain of the T-cell receptor/CD3 complex was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1A) .

GD2-BBz: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a GD2-specific 14.18 scFv, followed by the 4-1BB endodomain and the ζ-chain of the T-cell receptor/CD3 complex was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1A) .

DLL3-BBz: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a DLL3-specific V _HH, a human CD8α stalk and transmembrane domain, followed by the 4-1BB endodomain and the ζ-chain of the T-cell receptor/CD3 complex was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1A) .

MSLN-BBz: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a MSLN-specific V _HH, a human CD8α stalk and transmembrane domain, followed by the 4-1BB endodomain and the ζ-chain of the T-cell receptor/CD3 complex was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1A) .

For GPC2-BB28z and GPC2-28BBz: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a GPC2-specific V _HH, a human CD8α stalk and transmembrane domain, followed by a 4-1BB and a CD28 endodomain in tandem for the GPC2-BB28z; or a human CD28 stalk and transmembrane domain, followed a CD28 and a 4-1BB endodomain in tandem for the GPC2-28BBz and the ζ-chain of the T-cell receptor/CD3 complex was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1B) .

For GPC2-28OX40z: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a GPC2-specific V _HH, a human CD28 stalk and transmembrane domain, followed by a CD28 endodomain and an OX40 endodomain in tandem and the ζ-chain of the T-cell receptor/CD3 complex was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1B) .

For GPC2-2827z: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a GPC2-specific V _HH, a human CD28 stalk and transmembrane domain, followed by a CD28 endodomain and an CD27 endodomain in tandem and the ζ-chain of the T-cell receptor/CD3 complex was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1B) .

For GD2-28: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a GD2-specific 14.18 scFv, a human CD28 stalk, transmembrane and endodomains without the ζ-chain was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1C) .

For CD326-28: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a CD326-specific single chain variable fragment (scFv) , a human CD28 stalk, transmembrane and endodomains without the ζ-chain was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1C) .

For MSLN-28: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a MSLN-specific single domain antibody fragment (V _HH) , a human CD28 stalk, transmembrane and endodomains without the ζ-chain was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1C) .

For DLL3-28: a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a DLL3-specific single domain antibody fragment (V _HH) , a human CD28 stalk, transmembrane and endodomains without the ζ-chain was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1C) .

For GD2-28 (C141S, C168S mutant) : a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a GD2-specific 14.18 scFv, a mutated human CD28 stalk and transmembrane that cysteine at positions 141 and 168 are replaced by serine, a human CD28 endodomains without the ζ-chain was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1D) .

For MSLN-28 (C141S, C168S mutant) : a cDNA encoding an EF1α promoter, an N-terminal leader peptide, a MSLN-specific single domain antibody fragment (V _HH) , a mutated human CD28 stalk and transmembrane that cysteine at positions 141 and 168 are replaced by serine, a human CD28 endodomains without the ζ-chain was synthesized (GenScript, Piscataway) and cloned in frame in a lentiviral vector backbone (FIG. 1D) .

For GPC2-BBz/GD2-28: the GPC2-BBz CAR was sub-cloned into a vector upstream of a 2A sequence and a GD2 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a GD2-specific 14.18 single chain variable fragment (scFv) , a human CD28 stalk, transmembrane and endodomain without the ζ-chain (FIG. 1E) .

For GPC2-28z/GD2-BB: the GPC2-28z CAR was sub-cloned into a vector upstream of a 2A sequence and a GD2 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a GD2-specific 14.18 single chain variable fragment (scFv) , a human CD8α stalk and transmembrane, a 4-1BB endodomain without the ζ-chain (FIG. 1E) .

For GPC2-BBz/GD2-2 (or GPC2-BBz/GD2-CD2) : the GPC2-BBz CAR was sub-cloned into a vector upstream of a 2A sequence and a GD2 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a GD2-specific 14.18 single chain variable fragment (scFv) , a human CD28 stalk, a CD2 transmembrane and endodomain without the ζ-chain (FIG. 1E) .

For GPC2-BBz/GD2-ICOS: the GPC2-BBz CAR was sub-cloned into a vector upstream of a 2A sequence and a GD2 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a GD2-specific 14.18 single chain variable fragment (scFv) , a human CD28 stalk, an ICOS transmembrane and endodomain without the ζ-chain (FIG. 1E) .

For GPC2-BBz/MSLN-28: the GPC2-BBz CAR was sub-cloned into a vector upstream of a 2A sequence and a MSLN co-stimulatory receptor sequence comprising an N-terminal leader peptide, a MSLN-specific single domain antibody fragment (V _HH) , a human CD28 stalk, transmembrane and endodomain without the ζ-chain (FIG. 1E) .

For DLL3-BBz/GD2-28: the DLL3-BBz CAR was sub-cloned into a vector upstream of a 2A sequence and a GD2 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a GD2-specific 14.18 single chain variable fragment (scFv) , a human CD28 stalk, transmembrane and endodomains without the ζ-chain (FIG. 1E) .

For DLL3-BBz/CD326-28: the DLL3-BBz CAR was subcloned into a vector upstream of a 2A sequence and a CD326 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a CD326-specific single chain variable fragment (scFv) , a human CD28 stalk, transmembrane and endodomains without the ζ-chain (FIG. 1E) .

For DLL3-BBz/DLL3-28: the DLL3-BBz CAR was subcloned into a vector upstream of a 2A sequence and a DLL3 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a DLL3-specific single domain antibody fragment (V _HH) , a human CD28 stalk, transmembrane and endodomains without the ζ-chain (FIG. 1E) .

For GPC2-BBz/GD2-28 (C141S, C168S mutant) : GPC2-BBz CAR was sub-cloned into a vector upstream of a 2A sequence and a mutated GD2 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a GD2-specific 14.18 single chain variable fragment (scFv) , a mutated human CD28 stalk and transmembrane that cysteine at positions 141 and 168 are replaced by serine, a human CD28 endodomains without the ζ-chain (FIG. 1F) .

For GPC2-BBz/CD326-28 (C141S, C168S mutant) : GPC2-BBz CAR was sub-cloned into a vector upstream of a 2A sequence and a mutated CD326 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a CD326-specific single chain variable fragment (scFv) , a mutated human CD28 stalk and transmembrane that cysteine at positions 141 and 168 are replaced by serine, a human CD28 endodomains without the ζ-chain (FIG. 1F) .

For GPC2-BBz/GD2-Δ28: GPC2-BBz CAR was sub-cloned into a vector upstream of a 2A sequence and a GD2 co-stimulatory receptor sequence comprising an N-terminal leader peptide, a GD2-specific 14.18 single chain variable fragment (scFv) , a human CD28 stalk and transmembrane without the endodomains and ζ-chain (FIG. 1G) .

Components of CAR in accordance with some embodiments of the present disclosure may include SEQ ID NOs: 1-14 and 33-35. These and other sequences exemplied herein are provided in the table below.

Lentivirus production, T-cell transduction and expansion

To produce viral supernatant, HEK-293T cells were co-transfected with GPC2-BBz, GPC2-28z, GD2-BBz, DLL3-BBz, MSLN-BBz, GPC2-BB28z, GPC2-28BBz, GPC2-28OX40z, GPC2-2827z, GD2-28, CD326-28, MSLN-28, DLL3-28, GD2-28 (C141S, C168S mutant) , MSLN-28 (C141S, C168S mutant) , GPC2-BBz/GD2-28, GPC2-28z/GD2-BB, GPC2-BBz/GD2-2, GPC2-BBz/GD2-ICOS, GPC2-BBz/MSLN-28, GPC2-BBz/GD2-CD2, DLL3-BBz/GD2-28, DLL3-BBz/CD326-28, DLL3-BBz/DLL3-28, GD2-28z/GPC2-BB, GD2-BBz/GPC2-28, GPC2-BBz/GD2-28 (C141S, C168S mutant) , GPC2-BBz/CD326-28 (C141S, C168S mutant) , GPC2-BBz/MSLN-28 (C141S, C168S mutant) , GPC2-BBz/GD2-Δ28 lentiviral vectors psPAX2 (Addgene#12260) and pMD2. G (Addgene#12259) at a pre-optimized ratio with polyetherimide (PEI) per the manufacturer’s instructions. The supernatants were collected overnight after transfection. The virus-containing supernatants were filtered through a 0.45 μm PES filter, followed by ultra-centrifugation for lentivirus concentration. Viral aliquots were stored at -80℃.

Human PBMCs were purchased from HemaCare Corporation and primary human T cells were isolated using Miltenyi human PanT cell isolation kits (Miltenyi, #130096535) . The purified T cells, which contained > 98%CD3+ cells, were activated and expanded using Miltenyi anti-CD3/CD28 micro-beads (Miltenyi, #130091441) for 24-48 hours at a 2: 1 cell-to-bead ratio and suspended at 0.5x10 ⁶ cells/mL in growth medium supplemented with 300 U/mL IL-2. The pre-activated T cells were then transduced with lentivirus stock in the presence of 8 μg/mL polybrene by centrifugation at 1000 g, 32℃ for 1.5 h. The transduced cells were then transferred to the cell culture incubator for transgene expression under suitable conditions. Cells were counted every other day and fed with fresh growth medium every 2-3 days. The surface expression of CAR molecule and co-stimulatory receptor molecule in transduced T cells were analyzed by flow cytometry.

6.2. Example 2-Tumor cell lines and cell line construction

Human neuroblastoma cell line SH-SY5Y (ATCC, #CRL-2266) was cultured in EMEM) supplemented with 10%FBS. Human neuroblastoma cell line LAN-1 cells (ECACC, #06041201) and GPC2 knockout neuroblastoma cell line LAN-1/GPC2 ^KO were cultured in mixture of EMEM and Ham's F12 (1: 1 ratio) media with 10%FBS. Human embryonic kidney cell epidermoid carcinoma cell line HEK293 (ATCC, #CRL-1573) and stable GPC2 expression cell line HEK293/GPC2 were cultured in EMEM supplemented with 10%FBS. Human SCLC tumor cell lines SHP-77 (ATCC, #CRL-2195) and DMS-79 (ATCC, #CRL-2049) were cultured in RPMI-1640 media supplemented with 10%FBS.

To generate a GPC2 knockout neuroblastoma cell line (LAN-1/GPC2 ^KO) , plasmid vector pSpCas9 (BB) -2A-GFP (PX458) carrying the GPC2 targeting guide RNA and Cas9 was constructed. Neuroblastoma cell line LAN-1 (ECACC, #06041201) was transfected with the lentivirus. The transfected cells were plated in 96-well plates by limit dilution to generate isogenic single clones. Once the clonal culture reach more than 70%confluence, cells were harvested from wells and screened by Sanger sequencing to identify isogenic knockout or knockout clones. HEK293T clones that stably express human GPC2 (HEK293/GPC2) were prepared by transfecting HEK293 T cells (ATCC, #CRL-1573) with plvx-EF1α-puro plasmids containing sequences of human GPC2 (NM_152742.3) . The HEK293T clone that stably express human GPC2 (HEK293/GPC2) was also transiently transfected with human mesothelin (MSLN) mRNA (NM_005823) using electroporation. Successful construction of LAN-1/GPC2 ^KO and HEK293/GPC2 cell lines were validated by FACS analysis.

Surface expression of GPC2, GD2, DLL3 and CD326 of target cells were analyzed by flow cytometry. As shown in FIG. 2, SH-SY5Y, LAN-1 and HEK293/GPC2 were GPC2-positive (GPC2 ⁺) , LAN-1/GPC2 ^KO was GPC2-negative (GPC2 ^-) , HEK293 was GPC2-negative (GPC2 ^-) . As shown in FIG. 3, SH-SY5Y, LAN-1 and LAN-1/GPC2 ^KO were GD2-positive (GD2 ⁺) , HEK293/GPC2 and HEK293 were GD2-negative (GD2 ^-) . As shown in FIG. 4, SHP-77 and DMS-79 were DLL3-positive (DLL3 ⁺) , SH-SY5Y was DLL3-positive (DLL3 ⁺) , HEK293 was DLL3-negative positive (DLL3 ^-) . As shown in FIG. 5, SHP-77, DMS-79 and HEK293 were CD326-positive (CD326 ⁺) , SH-SY5Y was CD326-negative (CD326 ^-) . As shown in FIG. 6, SHP-77, DMS-79 and HEK293 were GD2-negative (GD2 ^-) , SH-SY5Y was GD2-positive (GD2 ⁺) .

6.3. Example 3-Chimeric co-stimulatory receptor enhances anti-tumor efficacy in vitro

The pre-activated T cells were transduced with lentivirus stock in the presence of 8 mg/mL polybrene and 300 IU/mL IL-2. T cells and lentivirus were centrifuged at 1000 g, 32℃for 1 h and placed in humidified cell culture incubator for transgene expression under suitable conditions. On day 5 or day 7 or day 10 post-transduction, transduced T cells were harvested and co-incubated with tumor cells at an effector (CAR-T) to target cell ratio of 0.33: 1 or 1: 1 for 20 hours. To assay the cytotoxicity of CAR-T cells on tumor cells, the Cytotoxicity Detection Kit (LDH) (Roche, #11644793001) assay reagents were prepared according to manufacturer’s instructions. Reaction mix was added to the cell-free supernatant of each sample to detect the LDH released from cells. Optical densities at OD492 nm and OD650 nm were measured by PHERStar Microplate Reader. Baseline LDH released from the target cell in the absence of effector cells and effector cell in the absence of target cells were subtracted from the total LDH amount. The target maximum release was obtained by adding Triton-X100 at a final concentration of 1%to target cells in the absence of effector cells at the time when the cytotoxicity assays initiated. Supernatant from target cells in the absence of effector cells was used for target minimum release. The specific cytotoxicity was calculated by the formula: % Target cell lysis = 100* [ (OD CAR-T cell +Target cell) - (OD CAR-T cell) - (OD Target cell) + (OD Buffer background) ] / (OD Target Maximum release –OD Target Minimum release) .

Exemplary CAR-T cells targeting GPC2 with or without the GD2 chimeric co-stimulatory receptor were selected and tested in the cytotoxicity assay. GD2-BBz a CAR construct that contains an anti-GD2 scFv and GPC2-BBz a CAR construct containing an anti-GPC2 V _HH served as positive controls. GD2-28, a GD2 chimeric co-stimulatory receptor without the ζ-chain served as a negative control. As shown in FIG. 7A, CAR-T cells of GPC2-BBz, GPC2-BBz/GD2-28, GD2-28 and GD2-BBz were tested against the neuroblastoma cell line SH-SY5Y (GPC2 and GD2 dual positive) . GPC2-BBz/GD2-28 CAR-T cells exhibited higher levels of cytotoxicity against SH-SY5Y cells than the two positive controls GPC2-BBz and GD2-BBz (FIG. 7A) . GPC2-BBz/GD2-28 CAR-T showed higher level of IFN-γ production than GPC2-BBz CAR-T but lower than that of the GD2-BBz CAR-T (FIG. 8A) . Negative control GD2-28 did not cause target cell lysis nor cytokine production against SH-SY5Y as expected (FIG. 7A and FIG. 8A) .

In another embodiment, exemplary CAR-T cells GPC2-BBz, GPC2-BBz/GD2-28, GD2-28 and GD2-BBz were tested against another GPC2 and GD2 dual positive neuroblastoma cell line LAN-1. GPC2-BBz/GD2-28 CAR-T cells exhibited similar levels of cytotoxicity against LAN-1 cells as the two positive controls GPC2-BBz and GD2-BBz (FIG. 7B) . GPC2-BBz/GD2-28 CAR-T showed higher level of IFN-γ production than GPC2-BBz CAR-T but lower than GD2-BBz CAR-T positive control (FIG. 8B) . Negative control GD2-28 did not cause target cell lysis nor cytokine production against LAN-1 (FIG. 7B and FIG. 8B) .

In another embodiment, exemplary CAR-T cells GPC2-BBz, GPC2-BBz/GD2-28, GD2-28 and GD2-BBz were tested against a GPC2 single positive cell line HEK293/GPC2. GPC2-BBz/GD2-28 CAR-T cells exhibited higher levels of cytotoxicity against HEK293/GPC2 cells than the positive controls GPC2-BBz (FIG. 7C) . GPC2-BBz/GD2-28 CAR-T showed higher level of IFN-γ production than GPC2-BBz CAR-T cells (FIG. 8C) . Both GD2-BBz and the negative control GD2-28 did not cause target cell lysis nor cytokine production against HEK293/GPC2 cells (FIG. 7C and FIG. 8C) .

In another embodiment, exemplary CAR-T cells GPC2-BBz, GPC2-BBz/GD2-28, GD2-28 and GD2-BBz were tested against a GPC2 knockout but GD2 single positive cell line LAN-1/GPC2 ^KO. Unlike the positive control GD2-BBz CAR-T that showed potent cytotoxicity and cytokine production against GD2 single positive LAN-1/GPC2 ^KO cells, GPC2-BBz/GD2-28 CAR-T and GPC2-BBz CAR-T cells did not exhibit cytotoxicity (FIG. 7D) nor IFN-γproduction (FIG. 8D) against LAN-1/GPC2 ^KO cells. Negative control GD2-28 did not cause target cell lysis nor cytokine production against LAN-1/GPC2 ^KO (FIG. 7D and FIG. 8D) .

In another embodiment, exemplary CAR-T cells GPC2-BBz, GPC2-BBz/GD2-28, GD2-28 and GD2-BBz were tested against a GPC2 and GD2 dual negative cell line HEK293. All CAR-T cells tested did not exhibit cytotoxicity nor IFN-γ production against HEK293 cells (FIG. 7E and FIG. 8E) .

Together, the data showed that the chimeric co-stimulatory receptor could improve the cytokine production function of the GPC2 CAR-T by providing an extra co-stimulatory signal, efficacy of cytotoxicity can also be improved. Addition of a GD2 chimeric co-stimulatory receptor in the CAR-T construct however did not alter the GPC2-specific cytotoxicity of GPC2-BBz CAR-T. GPC2-BBz/GD2-28 shared the same GPC2-dependent cytotoxicity against GPC2-expressing cell lines SH-SY5Y, LAN-1 and HEK293/GPC2 as the positive control GPC2-BBz CAR-T. GD2 chimeric co-stimulatory receptor alone could not trigger CAR-T cytotoxicity nor cytokine production.

6.4. Example 4-Chimeric co-stimulatory receptor improves CAR-T persistence

Persistence of CAR-T cells were evaluated in a serial tumor challenge assay. In brief, 4 ×10 ⁵ SH-SY5Y cells and 1.33×10 ⁵ CAR-T cells transduced with GPC2-BBz or GPC2-BBz/GD2-28 or GD2-28 or GD2-BBz lentiviral vectors were co-cultured in a 12 well plate using fresh growth medium without IL-2 (E: T ratio = 1: 3) . Cells were harvested after three days co-culture and samples were taken for cell counting using AOPI and T cell quantification by FACs. CAR-T cells were replated with fresh SH-SY5Y cells at a 1: 2 E: T ratio in growth medium without IL-2 to start the next round of tumor co-culture. Samples were taken for cell counting and T cell quantification at the end of each challenge every three days.

Exemplary CAR-T cells targeting GPC2 with or without GD2 co-stimulatory receptor were selected and tested in the serial challenge assay. GD2-BBz and GPC2-BBz served as positive controls.

GD2-28 without the ζ-chain served as a negative control. As shown in FIG. 9A, CAR-T cells of GPC2-BBz, GPC2-BBz/GD2-28, GD2-28 and GD2-BBz were repeatedly stimulated with SH-SY5Y. GPC2-BBz/GD2-28 exhibited significant improvement in long term persistence (FIG. 9A) and CAR-T cells expansion (FIG. 9C) comparing to the positive controls. A gradual decline in CAR positive T cells percentage was observed in both GPC2-BBz and GD2-BBz as CAR-T cells were reduced to the lower detection limit level in round 4 of target cell challenges (FIG. 9B) . Additional co-stimulation signal derived from the chimeric co-stimulatory receptor in the GPC2-BBz/GD2-28 CAR-T helped to maintain a more stable level of CAR positive T cells even after 6 round of target cell challenge (FIG. 9B) . The chimeric co-stimulatory receptor alone (GD2-28) could not trigger T cell expansion (FIG. 9C) .

Consistent with the cytotoxicity data, GPC2-BBz/GD2-28 CAR-T produced larger amount of IFN-γ than GPC2-BBz and GD2-BBz CAR-T cells after

round

2 and 3 of target cell challenge (FIG. 10) . GD2-28 co-stimulatory receptor alone could not trigger IFN-γ production in CAR-T cells (FIG. 10) .

Together, the data indicated that the chimeric co-stimulatory receptor could improve the CAR-T cell expansion and long term persistence by providing extra co-stimulatory signals. It was also suggested that primary signals from the T cell receptor complexes were required to drive these responses as GD2 co-stimulatory receptor alone without the ζ-chain failed to trigger T cell expansion.

6.5. Example 5-Chimeric co-stimulatory receptor augments production of multiple cytokines in CAR-T

Experiment was conducted to assess if chimeric co-stimulatory receptor could augment cytokines production in CAR-T cells using a LEGENDplex Human CD8/NK Panel (13-plex) assay kit (Biolegend, #740267) according to manufacturer’s instruction. In brief, CAR-T cells and target cell SH-SY5Y were co-incubated for 72 hours (E: T = 1: 3) . Culture supernatants were collected and diluted 2-folds with Assay Buffer. To prepare the reaction mix, 25 μL detection beads and 25 μL Assay Buffer were added to each standard and supernatant sample. After 2 hours incubation on a shaking platform, samples were washed twice with Wash Buffer. Detection antibodies (25 μL/sample) were added to each sample and further incubated on a shaking platform for 1 hour. SA-PE reagent (25 μL/sample) was added directly to each sample without washing and further incubated for 30 minutes. The unbound antibodies were removed after washing with Wash Buffer. Samples were re-suspended and collected by flow cytometry.

As shown in FIG. 11, exemplary CAR-T with chimeric co-stimulatory receptor (GPC2-BBz/GD2-28) produced larger amounts of inflammatory cytokines IL-2, IL-6, TNFα, IFN-γ and cytotoxins (granzyme A and granzyme B) than the parental CAR-T GPC2-BBz when co-incubated with SH-SY5Y. Augment of cytokine production in GPC2-BBz/GD2-28 matched well with the characteristics of CD28 signaling cascade (see, Golumba-Nagy et al., Mol. Ther. 26 (9) : 2218-2230 (2018) ) .

6.6. Example 6-Chimeric co-stimulatory receptor promotes durable tumor elimination by CAR-T cells

To evaluate the antitumor activities of GPC2-specific CAR-T cells in vivo, NCG mice (NOD-PrkdcCd5I12rgCd/NjuCrl) were subcutaneously injected with neuroblastoma SH-SY5Y cells. A single dose of untransduced T cells (23.6×10 ⁶) or CAR-T cells (0.5×10 ⁶) was administered intravenously to tumor engrafted mice 12 days after tumor inoculation (FIG. 12) . Tumor length (L) and width (W) were measured by caliper every 3-4 days after CAR-T cells treatment. Tumor volume was estimated using formula: V = (W ²× L) /2. Fourteen days after treatment, the NCG mice treated with GPC2-BBz and GPC2-BBz/GD2-28 CAR expressing T cells all showed reduced tumor burden comparing with the untransduced T cell-treated group (FIG. 13A) . Tumor regression in GPC2-BBz/GD2-28 CAR-T cells treated mice was more pronounced than the GPC2-BBz positive control. All GPC2-BBz CAR-T cells treated mice (5/5) suppressed tumor growth but failed to eliminate the xenograft tumor (FIG. 13A) . GPC2-BBz CAR-T treated mice were sacrificed on day 30 post treatment due to disease progression (FIG. 13A) . In comparison, 5/5 (100%) of GPC2-BBz/GD2-28 CAR-T cells treated mice had durable tumor remission. Although 1/5 (20%) of GPC2-BBz/GD2-28 CAR-T cells treated mice was sacrificed early on day 41 post treatment due to development of graft versus host disease (GvHD) , the remaining mice (4/5, 80%) achieved tumor-free from day 48 post treatment without recrudescence (FIG. 13A) . The data highlighted the superiority of GD2 chimeric co-stimulatory receptor armored CAR-T cells in tumor regression and protection of mice from disease progression. Remarkably, no significant weight loss was observed from NCG mice receiving GPC2-targeted CAR-T cells, suggested 0.5×10 ⁶ GPC2-BBz and GPC2-BBz/GD2-28 CAR-T cells were well tolerated by NCG mice (FIG. 13B) .

Moreover, the expansion and persistence of CAR-T cells in vivo are also considered as critical predictors of durable clinical tumor regression in patients with cancer. To understand the basic kinetics of infused CAR-T cells, the percentage of CAR-T cells in peripheral blood of NCG mice was assessed using flow cytometry. As shown in FIG. 13C, an elevated percentage of CAR-T cells in peripheral blood of NCG mice was observed from day 14 post treatment. Average 4.68±3.34%of CAR positive T cells were found in the peripheral blood of NCG mice treated with 0.5×10 ⁶ GPC2-BBz CAR-T cells (FIG. 13C) . The percentage of CAR positive T cells in peripheral blood of GPC2-BBz/GD2-28 CAR-T treated mice (14.05±3.35%on day 14) was at least 3 folds higher than that of GPC2-BBz (FIG. 13C) . The percentage of CAR positive T cell was reduced when GPC2-BBz/GD2-28 CAR-T treated mice became disease free on day 48.

6.7. Example 7-CD28 signaling domain is indispensable for the function of chimeric co-stimulatory receptor

To investigate if CD28 co-stimulatory signaling domain is essential for the function of chimeric co-stimulatory receptor, GPC2-BBz/GD2-28 was compared with GPC2-BBz/GD2-Δ28 in cytotoxicity, CAR-T persistence and expansion after target cell stimulations. Followed the detailed descriptions in Example 3, CAR-T cells were co-cultured with SH-SY5Y, LAN-1, LAN-1/GPC2 ^KO and HEK293 target cells, level of target cell cytotolysis was estimated using Cytotoxicity Detection Kit (LDH) (Roche, #11644793001) assay reagents according to manufacturer's instruction.

Exemplary CAR-T cells targeting GPC2 with the GD2 chimeric co-stimulatory receptor or with the truncated GD2 chimeric co-stimulatory receptor devoid of CD28 intracellular signaling domain were selected and tested in the cytotoxicity assay. GPC2-BBz a CAR construct containing an anti-GPC2 V _HH served as positive controls. As shown in FIG. 14A and FIG. 14B, CAR-T cells were tested against the neuroblastoma cell line SH-SY5Y and LAN-1 (GPC2 and GD2 dual positive) . GPC2-BBz/GD2-Δ28 CAR-T cells exhibited similar levels of cytotoxicity against SH-SY5Y cells as GPC2-BBz and GPC2-BBz/GD2-28 (FIG. 14A and FIG. 14B) . GPC2-BBz/GD2-Δ28 CAR-T had comparible level of IFN-γ production as GPC2-BBz but lower than that of the GPC2-BBz/GD2-28 CAR-T (FIG. 15A and FIG. 15B) . Untransduced T cells did not cause target cell lysis nor cytokine production against SH-SY5Y and LAN-1 as expected (FIG. 14A and FIG. 14B, FIG. 15A and FIG. 15B) .

In another embodiment, exemplary CAR-T cells GPC2-BBz, GPC2-BBz/GD2-28 and GPC2-BBz/GD2-Δ28 were tested against GPC2 knockout but GD2 single positive cell line LAN-1/GPC2 ^KO. GPC2-BBz, GPC2-BBz/GD2-28 and GPC2-BBz/GD2-Δ28 cells did not exhibit cytotoxicity (FIG. 14C) nor IFN-γ production (FIG. 15C) against LAN-1/GPC2 ^KO cells. Negative control untransduced T cells did not cause target cell lysis nor cytokine production against LAN-1/GPC2 ^KO (FIG. 14C and FIG. 15C) .

In another embodiment, exemplary CAR-T cells GPC2-BBz, GPC2-BBz/GD2-28 and GPC2-BBz/GD2-Δ28 were tested against a GPC2 and GD2 dual negative cell line HEK293. All CAR-T cells tested did not exhibit cytotoxicity nor IFN-γ production against HEK293 cells (FIG. 14D and FIG. 15D) .

Together, the data showed that the CD28 signaling domain in chimeric co-stimulatory receptor, though was dispensible for immediate target cell cytolysis, was essential for enhancing cytokine production.

Furthermore, exemplary CAR-T cells GPC2-BBz, GPC2-BBz/GD2-28 and GPC2-BBz/GD2-Δ28 were selected and tested in the serial challenge assay following the detailed descriptions in Example 4. As shown in FIG. 16A, CAR-T cells were repeatedly stimulated with SH-SY5Y. GPC2-BBz/GD2-28 significantly improved the long term persistence (FIG. 16A and FIG. 16B) and expansion (FIG. 16C) of CAR-T cells comparing to the parental CAR-T GPC2-BBz. Chimeric co-stimulatory receptor devoid of CD28 intracellular signaling domain (GPC2-BBz/GD2-Δ28) failed to improve CAR-T expansion and persistence (FIG. 16A, FIG. 16B and FIG. 16C) .

Collectively, the data suggested CD28 co-stimulatory signaling domain in the chimeric co-stimulatory receptor was essential for T cell expansion, persistence and cytokine production enhancement.

6.8. Example 8-Chimeric co-stimulatory receptor provides enhanced persistency compared to the 3rd generation GPC2 CAR-Ts

To assess whether the chimeric co-stimulatory receptor could augment CAR-T cells cytotoxicity and improving GPC2 CAR-T cells long term persistence comparing with 3 ^rd generation GPC2 CAR-Ts that comprising two costimulatory domains, in vitro cytotoxicity and CAR-T persistence under serial target cell challenges were measured following the experimental procedures described in Example 3 and Example 4. Exemplary CAR-T GPC2-BBz/GD2-28 showed similar level of cytotoxicity as the control CAR-Ts (GPC2-BBz, GPC2-28z) and the 3 ^rd generation GPC2 CAR-Ts (GPC2-BB28z, GPC2-28BBz) and 3 ^rd generation GPC2 CAR-Ts (GPC2-28OX40z, GPC2-2827z) against SH-SY5Y (FIG. 17) . In agreement with previous data, chimeric co-receptor armored CAR-T (GPC2-BBz/GD2-28) showed higher level of IFN-γproduction than the control CAR-Ts (GPC2-BBz, GPC2-28z) and the 3 ^rd generation CAR-Ts (GPC2-BB28z, GPC2-28BBz, GPC2-28OX40z, GPC2-2827z) (FIG. 18) .

GPC2-BBz/GD2-28 showed improved long term persistence comparing with control CAR-Ts (GPC2-BBz, GPC2-28z) and the 3 ^rd generation CAR-Ts (GPC2-BB28z, GPC2-28BBz, GPC2-28OX40z, GPC2-2827z) after multiple rounds of target cell challenges (FIG. 19A) . On the contrary, the 3 ^rd generation CAR-Ts (GPC2-BB28z, GPC2-28BBz, GPC2-28OX40z, GPC2-2827z) did not significantly improve CAR-T persistence comparing with the control CAR-Ts (GPC2-BBz, GPC2-28z) (FIG. 19A) . The 3 ^rd generation CAR-Ts (GPC2-BB28z, GPC2-28BBz, GPC2-28OX40z, GPC2-2827z) also failed to maintain the T cell persistence. Percentage of CAR positive T cells dropped to the lower detection limit level in round 4 of target cell challenges (FIG. 19B) . GPC2-BBz/GD2-28 CAR-T however maintained more stable level of CAR positive T cells and better CAR-T expansion after several rounds of target cell challenge (FIG. 19B, FIG. 19C) .

Together, the data indicated that the chimeric co-stimulatory receptor could improve CAR-T cell expansion and long term persistence and it is more superior to the 3 ^rd generation CAR-T cells containing dual co-stimulatory domains.

6.9. Example 9-CD28 signaling domain is optimized for the function of chimeric co-stimulatory receptor

To assess if the CD28 signaling domain is optimized for the functions of chimeric co-stimulatory receptor, GPC2 CAR-Ts armored with GD2 co-stimulatory receptors that harboring different co-stimulatory domains were selected and tested in the serial challenge assay as described in Example 4.

In one embodiment, exemplary CAR-Ts GPC2-BBz/GD2-28 was compared with GPC2-28z/GD2-BB (chimeric co-stimulatory receptor contained 4-1BB intracellular signaling domain) . Conventional GPC2 CAR-Ts (GPC2-BBz and GPC2-28z) served as positive controls. Despite GPC2-28z/GD2-BB and GPC2-BBz/GD2-28 showed similar improvement in long term persistence of total T cells comparing to the control CAR-Ts (GPC2-BBz, GPC2-28z) (FIG. 20A) , GPC2-28z/GD2-BB CAR-T cells had poor persistency and failed to expand after target cell challenges (FIG. 20B and FIG. 20C) . On the contrary, significant CAR-T cells expansion was observed in GPC2-BBz/GD2-28, consistent with previous findings (FIG. 20C) .

In another embodiment, exemplary GD2 co-stimulatory receptors harboring CD28, CD2 or ICOS co-stimulatory domains were selected and tested in the serial challenge assay. GPC2-BBz/GD2-28 was compared to GPC2-BBz/GD2-2 (chimeric co-stimulatory receptor contained CD2 intracellular signaling domain) and GPC2-BBz/GD2-ICOS (chimeric co-stimulatory receptor containing ICOS intracellular signaling domain) . Conventional GPC2 CAR-Ts (GPC2-BBz) served as positive controls. As shown in FIG. 21A, CAR-T cells of GPC2-BBz, GPC2-BBz/GD2-28, GPC2-BBz/GD2-CD2 and GPC2-BBz/GD2-ICOS were repeatedly stimulated with SH-SY5Y. GPC2-BBz/GD2-28 significantly improved the long term persistence (FIG. 21A) and expansion (FIG. 21C) of CAR-T cells comparing to the parental CAR-T GPC2-BBz. Replacing the CD28 co-stimulatory domains with CD2 or ICOS co-stimulatory domains abolished the enhancement (FIG. 21A and FIG. 21B) .

Consistent with the cytotoxicity data, GPC2-BBz/GD2-28 CAR-T produced larger amount of IFN-γ than GPC2-BBz/GD2-2 and GPC2-BBz/GD2-ICOS after

round

2 and 3 of target cell challenge (FIG. 22) .

Collectively, the data suggested CD28 co-stimulatory signaling domain has more superior effect on T cell expansion and anti-tumor efficacy enhancement comparing to 4-1BB, CD2 and ICOS signaling domains. CD28 signaling domain is therefore optimized for the function of chimeric co-stimulatory receptor.

6.10. Example 10-Cytotoxicity of GD2 chimeric co-stimulatory receptor armored GPC2 CAR-T is not GD2-level dependent

To assess if the cytotoxicity of GD2 chimeric co-stimulatory receptor armored GPC2 CAR-T is GD2-level dependent, CAR-T cells were co-cultured with SH-SY5Y in presence of an anti-idiotype antibody Ganglidiomab (see Lode et al., Cancer Immunol Immunother, 62 (6) : 999-1010 (2013) ) at indicated concentrations. Therefore it might neutralize the activity of GD2 co-stimulatory receptor by blocking the binding of GD2 antibody with GD2. In another embodiment, mouse IgG2a, instead of Ganglidiomab, was added to the co-culture and served as negative controls.

As shown in FIG. 23A to FIG. 23C, level of GD2-BBz cytotoxicity reduced in a GD2 dose-dependent manner as the concentrations of Ganglidiomab increased from 0.05 μg/mL to 5 μg/mL, whereas mouse IgG2a at the same concentrations had no effects on CAR-T’s cytotoxicity (FIG. 24A, FIG. 24B and FIG. 24C) . Data therefore confirmed the activity of anti-idiotype antibody Ganglidiomab in neutralizing the activity of GD2-BBz CAR-T by blocking the binding of GD2 antibody with GD2. Intriguingly, cytotoxicity of neither GPC2-BBz nor GPC2-BBz/GD2-28 was affected by the presence of Ganglidiomab (FIG. 23A, FIG. 23B and FIG. 23C) . Together, data suggested that cytotoxicity of GD2 chimeric co-stimulatory receptor armored GPC2 CAR-T is independent of GD2.

6.11. Example 11-High levels of target antigen expression activate the chimericco-stimulatory receptor

Experiments were conducted to elucidate a key mechanism underpinning the contributions of chimeric co-stimulatory receptor in CAR-T cells cytotoxicity and persistence: the ligand or target antigen of chimeric co-stimulatory receptor has to be abundantly expressed on target cell. To address this issues, T cell persistence and CAR-T cell expansion of GPC2-BBz/MSLN-28 was tested in the serial challenge assay as described in Example 4 with modifications. In brief, GPC2-BBz/MSLN-28 CAR-T cells were co-cultured with different HEK293/GPC2 clones that was transiently transfected with 1, 4 or 20 μg/test human mesothelin (MSLN) mRNA (NM_005823) (GPC2 and MSLN dual positive) . CAR-T cells were repeatly challenged with freshly prepared target cells every three days. T cell persistence and CAR-T cell expansion of GPC2-BBz/MSLN-28 was compared to that of MSLN-BBz (positive control for MSLN antigen) and GPC2-BBz (negative control for the MSLN antigen) .

As shown in FIG. 25, level of MSLN expression was estimated in HEK293/GPC2 target cells transfected with various amounts of MSLN mRNA. Target espression was calculated as: Expression Log_shift = Log ₁₀ (MFI _{anti-MSLN antibody} /MFI _{isotype control}) . HEK293/GPC2 target cells transfected with 1 μg/test human MSLN mRNA having MSLN expression at 0.5 Log_shift (FIG. 25) . HEK293/GPC2 target cells transfected with 4 or 20 μg/test human MSLN mRNA resulting MSLN expression at 0.9 and 1.5 Log_shift respectively (FIG. 25) . In conclusion, the level of MSLN expression HEK293/GPC2 target cells was positively correlated with amount of MSLN mRNA transfected.

In one embodiment, exemplary CAR-T GPC2-BBz was stimulatd with the MSLN-expressing HEK293/GPC2 cells as described above. All tested GPC2-BBz groups showed similar total T cells long term persistence and CAR-T cells expansion as those challenged with parental HEK293/GPC2 cell (GPC2 positive but MSLN negative) (FIG. 26A and FIG. 26B) . Data suggested MSLN antigen expression in HEK293/GPC2 target cells did not alter the T cell persistence and CAR-T expansion for GPC2-BBz as expected.

In another embodiment, exemplary CAR-T MSLN-BBz was stimulatd with the MSLN-expressing HEK293/GPC2 cells as described above. Differed from that of GPC2-BBz, MSLN-BBz CAR-Ts showed improved total T cells long term persistence as the level of MSLN expression increased in HEK293/GPC2 cells (FIG. 27A) . However, the improvement in total T cells long term persistence did not translate to CAR-T cells expansion (FIG. 27B) . Data suggested high level of MLSN antigen expression could promote the long term persistence of MSLN-BBz but having limited effect on CAR-T expansion.

In another embodiment, exemplary chimeric co-stimulatory receptor armored CAR-T GPC2-BBz/MSLN-28 was co-cultured with the MSLN-expressing HEK293/GPC2 cells as described above. Similar as MSLN-BBz CAR-T, HEK293/GPC2 cells expressing high level of MSLN (20 μg/test MLSN mRNA) improved total T cells long term persistence of GPC2-BBz/MSLN-28 (FIG. 28A) . Contrary to the MSLN-BBz and GPC2-BBz, GPC2-BBz/MSLN-28 CAR-T also had significant CAR-T expansion (FIG. 28B) . Intriguingly, the extended T cell persistence and improved CAR-T expansion could only be achieved when GPC2-BBz/MSLN-28 CAR-T was stimulated with HEK293/GPC2 cells expressing high level of MSLN (20 μg/test MLSN mRNA) . Untransduced control T cells did not respond to any HEK293/GPC2 target cells tested (FIG. 29A, FIG. 29B) . Therefore data suggested that the MSLN chimeric co-stimulatory receptor has an activation threshold that required ligand or target antigen to be abundantly expressed on target cell in order to trigger the downstream signaling cascades.

6.12. Example 12-Chimeric co-stimulatory receptors improve DLL3 CAR-T functions

Followed the methods described in Example 3 and Example 4, experiments were conducted to further elucidate the potentials of chimeric co-stimulatory receptor in combination with CAR-T cells that were specific for other target antigens. To address these issues, exemplary DLL3-BBz CAR-T cell specific for the neuroendocrine tumors, including small cell lung cancer (SCLC) , was compared with several chimeric co-stimulatory receptor armored DLL3 CAR-Ts (DLL3-BBz/GD2-28, DLL3-BBz/DLL3-28 and DLL3-BBz/CD326-28) for their cytotoxicities and CAR-Ts’ persistency after serial challenges.

Firstly, the DLL3 CAR-T was armored with the GD2 chimeric co-stimulatory receptor. As shown in FIG. 30A and FIG. 31A, DLL3-BBz/GD2-28 had augmented cytotoxicity and IFN-γ production against the DLL3 ⁺ GD2 ⁺ NBL cell line SH-SY5Y when comparing with DLL3-BBz. The DLL3-BBz/GD2-28 CAR-T also had comparable levels of cytotoxicity and cytokine production as the conventional DLL3-BBz CAR-T when co-cultured with the DLL3 ⁺ GD2 ^-SCLC target cells (SHP-77 and DMS-79) (FIG. 30B, FIG. 30C, FIG. 31B, FIG. 31C) . More importantly, no non-specific cytotoxicity against the HEK293 cell line (DLL3 ^-GD2 ^-) was observed (FIG. 30D, FIG. 31D) . In line with the results of GPC2-BBz/GD2-28 described in Example 3, the data argued that GD2 chimeric co-stimulator receptor could augment CAR-T cytotoxicity of both GPC2-specific and DLL3-specific CAR-T cells against tumor cell lines, especially for those tumor cells expressing intermediate to low-level of target antigens such as SH-SY5Y (FIG. 2 and FIG. 4) .

Furthermore, experiments were conducted to explore if the chimeric co-stimulatory receptor and primary CAR could target at the same molecule. To address this issue, two different chimeric co-stimulatory receptors were constructed to bind with DLL3 (high expression in SHP-77 and DMS-79 but the level was lower than CD326) and CD326 (abundantly expressed in SHP-77 and DMS-79) respectively. The armored DLL-3 CAR-Ts DLL3-BBz/DLL3-28 and DLL3-BBz/CD326-28 were compared with DLL3-BBz against two SCLC cell lines SHP-77 and DMS-79 (DLL3 ⁺ CD326 ⁺) , one neuroblastoma cell line SH-SY5Y (DLL3 ⁺ CD326 ^-) and the HEK293 cell (DLL3 ^-CD326 ⁺) . As shown in FIG. 32A and FIG. 32B, DLL3-BBz/DLL3-28 and DLL3-BBz/CD326-28 had similar levels of CAR-T cytotolysis against the DLL3 ⁺ cell lines SHP-77 and DMS-79 as the parental CAR-T DLL3-BBz. DLL3-BBz/CD326-28 however had higher level of IFN-γ production than DLL3-BBz while the cytokine production in DLL3-BBz/DLL3-28 was attenuated (FIG. 33A and FIG. 33B) . Furthermore, when CAR-Ts were cultured with SH-SY5Y, DLL3-BBz/CD326-28 could augment CAR-T cytotoxicity while DLL3-BBz/DLL3-28 could not (FIG. 32C, FIG. 33C) .

The CD326 chimeric co-stimulatory receptor may also lowered the CAR-T activation threshold given that DLL3 ^-CD326 ⁺ HEK293 could up-regulate IFN-γ production of DLL3-BBz/CD326-28 but not inducing cytotoxicity (FIG. 32D, FIG. 33D) .

Lastly, the chimeric co-stimulatory receptor armored DLL3 CAR-Ts (DLL3-BBz/DLL3-28, DLL3-BBz/CD326-28) were evaluated in a serial tumor challenge assay following the description in Example 4 with modifications. In brief, 6×10 ⁵ SHP-77 cells and 6×10 ⁵ CAR positive T cells were co-cultured in a 12 well plate without IL-2 (E: T ratio = 1: 1) . CAR-T cells were replated with fresh SHP-77 cells at a 1: 1 E: T ratio every 48 hours. Samples were taken for cell counting and T cell quantification at the end of each challenge. The conventional DLL3-BBz CAR-T served as a positive control.

Consistent with the cytotoxicity result, DLL3-BBz/CD326-28 showed improved long term persistence comparing with control CAR-T (DLL3-BBz) after serial challenges (FIG. 34A) . On the contrary, the overall CAR-T persistence was attenuated in DLL3-BBz/DLL3-28 comparing with DLL3-BBz (FIG. 34A) . The DLL3-BBz/DLL3-28 CAR-T also failed to expand after several rounds of target cell challenges despite percentage of CAR positive T cells increased over time (FIG. 34B and FIG. 34C) . DLL3-BBz/CD326-28, however, showed the highest level of CAR-T expansion and IFN-γ production after serial target cell challenges (FIG. 34C and FIG. 35) . Together, data indicated that chimeric co-stimulatory receptor that targets at the aberrantly expressed CD326 could improve the CAR-T persistence and cytokine production of DLL3 CAR-T. In comparison, the DLL3 chimeric co-stimulatory receptor failed to improve DLL3 CAR-T functions. Therefore the data suggested that the chimeric co-stimulatory receptor and the primary CAR should target different molecules.

6.13. Example 13-De-dimerization of chimeric co-stimulatory receptors can reduce armored CAR-T non-specifiic cytotoxicity

Two adjacent cysteins of indivudal chain of polypeptide or protein can from interchain disulfide bonds that pull two individual proteins together as homodimers or heterodimers. This mechanism also facilates the activation of CAR molecules comprising CD8α or CD28 hinge and transmembrane (see Muller, et al., Frontiers in Immunology, 12: 639818 (2021) ; Jayaraman, et al., EBioMedicine, 58: 102931 (2020) ) . Mutations that reduce the CAR molecule dimerizations can abrogate CAR T activation, hence loweing tonix signal and the potential of non-antigen specific activation (see Salzer, et al., Nature Communications, 11: 4166 (2020) ; Shu, et al., Molecular Therapy -Oncolytics. 20: 325-341 (2021) ) .

To evaluate the effects of dimerization on the functions of chimeric co-stimulatory receptor, several chimeric co-stimulatory receptors with cysteine-to-serine mutations in the CD28 hinge and transmembrane domains at positions 141 and 168 were constructed. The three armored CAR-Ts included GPC2-BBz/MSLN-28 (C141S, C168S mutant) , GPC2-BBz/GD2-28 (C141S, C168S mutant) and GPC2-BBz/B7-H3-28 (C141S, C168S mutant) , were tested for their levels of cytotoxicity and cytokine productions against tumor target cells, their long term persistence and CAR-T expansion after serial challenges as described in Example 3 and Example 4.

In one embodiment, GPC2-BBz/MSLN-28 (C141S, C168S mutant) was compared with GPC2-BBz/MSLN-28 and GPC2-BBz for their target antigen-specific cytotoxicity. As shown in FIG. 36A and FIG. 36B, GPC2-BBz/MSLN-28 (C141S, C168S mutant) showed similar levels of cytotoxicity as the GPC2-BBz/MSLN-28 and GPC2-BBz against GPC2 positive MSLN negative target cells (LAN-1 and HEK293/GPC2) . Similar to GPC2-BBz/MSLN-28 and GPC2-BBz, GPC2-BBz/MSLN-28 (C141S, C168S mutant) also had no non-specific cytotoxicity against GPC2 and MSLN dual negative target cell LAN-1/GPC2 ^KO (FIG. 36C) . GPC2-BBz/MSLN-28 (C141S, C168S mutant) in general also had similar level of IFN-γ production as the GPC2-BBz/MSLN-28 and GPC2-BBz CAR-T cells when co-cultured with LAN-1, HEK293/GPC2 and HEK293 target cells (FIG. 37A to FIG. 37C) . Intriguingly, certain level of non-GPC2 specific cytotoxicity and cytokine production was observed in GPC2-BBz/MSLN-28 when cultured with LAN-1/GPC2 ^KO cells transfected with 20 μg MSLN mRNA (GPC2 negative MSLN positive) (FIG. 36D and FIG. 37D) . On the contrary, cysteine-to-serine mutations in the CD28 hinge and transmembrane domains abrogated the non-specificity of MSLN chimeric co-stimulatory receptor armored CAR-T (FIG. 36D and FIG. 37D) .

In another embodiment, GPC2-BBz/GD-28 (C141S, C168S mutant) was compared with GPC2-BBz/GD2-28 and GPC2-BBz for their target antigen-specific cytotoxicity. As shown in FIG. 38A and FIG. 38B, GPC2-BBz/GD2-28 (C141S, C168S mutant) showed similar levels of cytotoxicity as the GPC2-BBz/GD2-28 and GPC2-BBz against GPC2 and GD2 dual positive or GPC2 single positive target cells (LAN-1 and HEK293/GPC2) . In consistence with previous results, both GPC2-BBz/GD2-28 (C141S, C168S mutant) and GPC2-BBz/GD2-28 CAR-Ts had no non-specific cytotoxicity against GPC2 and GD2 dual negative (HEK293) nor the GD2 signal positive (LAN-1/GPC2 ^KO) target cells (FIG. 38C and FIG. 38D) . GPC2-BBz/GD-28 (C141S, C168S mutant) however had lower level of IFN-γ production than the GPC2-BBz/GD2-28 when co-cultured with LAN-1 (GPC2 and GD2 dual positive) and LAN-1/GPC2 ^KO (GPC2 negative, GD2 positive) as GD2 was presence on target cells (FIG. 39A and FIG. 39D) . GPC2-BBz/GD2-28 (C141S, C168S mutant) showed similar levels of IFN-γ production as the GPC2-BBz/GD2-28 and GPC2-BBz when GD2 was absent in target cells (FIG. 39B and FIG. 39C) .

In another embodiment, GPC2-BBz/B7-H3-28 (C141S, C168S mutant) was compared with GPC2-BBz/B7-H3-28 and GPC2-BBz for their target antigen-specific cytotoxicity. As shown in FIG. 40A and FIG. 40B, GPC2-BBz/B7-H3-28 (C141S, C168S mutant) showed lower level of cytotoxicity than the GPC2-BBz/B7-H3-28 but similar to that of GPC2-BBz against GPC2 and B7-H3 dual positive target cells (LAN-1 and HEK293/GPC2) . Contrary to the GD2 co-stimulatory receptor armored CAR-Ts that had no non-specific cytotoxicity, GPC2-BBz/B7-H3-28 was found causing certain level of non-GPC2 specific cytotoxicity in GPC2 negative but B7-H3 positive target cells (LAN-1/GPC2 ^KO and A431) (FIG. 40C and FIG. 40D) . However, cysteine-to-serine mutations in the CD28 hinge and transmembrane domains of GPC2-BBz/B7-H3-28 (C141S, C168S mutant) abrogated the non-GPC2 specificity cytotoxicity of B7-H3 chimeric co-stimulatory receptor armored CAR-T (FIG. 40C and FIG. 40D) . GPC2-BBz/B7-H3-28 (C141S, C168S mutant) had similar or higher level of IFN-γ production as the GPC2-BBz/B7-H3-28 cells when co-cultured with LAN-1, HEK293/GPC2, LAN-1/GPC2 ^KO and A431 target cells (FIG. 41A to FIG. 41D) .

Collectively, the data showed chimeric co-stimulatory receptors targeting certain antigens other than GD2 might cause non-specific cytotoxicity. However, mutations in the CD28 hinge and transmembrane domains that abolished the intrinsic dimerization of chimeric co-stimulatory receptors could reduce the non-specific cytotoxicity.

6.14. Example 14-The effects of chimeric co-stimulatory receptor de-dimerization on armored CAR-T persistence and expansion

To assess if the mutated CD28 hinge and transmembrane domains would compromise the functions of chimeric co-stimulatory receptor, GPC2 CAR-Ts armored with mutated GD2 co-stimulatory receptor GPC2-BBz/GD2-28 (C141S, C168S mutant) or mutated B7-H3 co-stimulatory receptor GPC2-BBz/B7-H3-28 (C141S, C168S mutant) were selected and tested against neuroblastoma tumor cell LAN-1 (positive for GPC2, GD2 and B7-H3) in the serial challenge assay as described in Example 4.

In one embodiment, exemplary CAR-Ts GPC2-BBz/GD2-28 (C141S, C168S mutant) and GPC2-BBz/B7-H3-28 (C141S, C168S mutant) CAR-Ts were compared with GPC2-BBz/GD2-28 and GPC2-BBz/B7-H3-28. Conventional GPC2 CAR-T (GPC2-BBz) served as positive controls. Data revealed that all co-stimulatory receptor armored CAR-Ts GPC2-BBz/GD2-28, GPC2-BBz/B7-H3-28, GPC2-BBz/GD2-28 (C141S, C168S mutant) and GPC2-BBz/B7-H3-28 (C141S, C168S mutant) showed significant improvement in long term persistence (FIG. 42A and FIG. 42C) , total T cells expansion (FIG. 42B) and CAR-T cells expansion (FIG. 42D) comparing to that of control CAR-T GPC2-BBz.

Since GPC2-BBz/GD2-28 (C141S, C168S mutant) was found to have reduction in IFN-γ production comparing to GPC2-BBz/GD2-28 as reported in Example 13, this functional impairement also was translated to poorer long term persistence and T cells expansions of GPC2-BBz/GD2-28 (C141S, C168S mutant) (FIG. 42A to FIG. 42D) . Data therefore suggested mutated CD28 hinge and transmembrane domains that reduced intrinsic dimerization of chimeric co-stimulatory receptor could weaken the functions of GD2 co-stimulatory receptor. Intriguingly such a functional impairement was not observed in GPC2-BBz/B7-H3-28 (C141S, C168S mutant) that shown almost identical level of CAR-T long term persistence and expansion as the parential CAR-T GPC2-BBz/B7-H3-28 (FIG. 42A to FIG. 42D) .

Collectively, it was demonstrated that mutated CD28 hinge and mutated transmembrane domains that reduced the intrinsic dimerization of chimeric co-stimulatory receptor could weaken the functions of GD2 chimeric co-stimulatory receptor comprising a GD2 antibody scFv derived from clone 14.18. However, the same mutations had no effects on CAR-T cell persistence and expansion of B7-H3 chimeric co-stimulatory receptor armored GPC2 CAR-T. In fact, such mutations could be beneficial to the chimeric co-stimulatory receptors that targeted at certain antigens other than GD2 because the chimeric co-stimulatory receptor-related cytotoxicity could be eliminated as describing in Example 13. Therefore, both wild type and mutated CD28 domains are applicable to the chimeric co-stimulatory receptors for improving function of CAR-T cells.

From the foregoing, it will be appreciated that, although specific embodiments have been described herein for the purpose of illustration, various modifications may be made without deviating from the spirit and scope of what is provided herein. All of the references referred to above are incorporated herein by reference in their entireties.

Claims

A system for inducing activity of an immune cell, comprising:

(a) a chimeric co-stimulatory receptor comprising (i) a first extracelluar domain capable of binding to a first epitope, (ii) a first transmembrane domain, and (iii) a first intracellular domain comprising a first co-stimulatory domain and devoid of a signaling domain of CD3 zeta; and

(b) a chimeric antigen receptor (CAR) comprising (i) a second extracellular domain capable of binding to a second epitope, (ii) a second transmembrane domain, and (iii) a second intracellular domain comprising a signaling domain and a second co-stimulatory domain, wherein optionally the second intracellular domain further comprises a third co-stimulatory domain.
The system of claim 1, wherein the chimeric co-stimulatory receptor further comprises a first hinge region and the CAR further comprises a second hinge region.
The system of claim 2, wherein the first hinge region is different from the second hinge region.
The system of any one of claim 2 or 3, wherein:

(i) the first hinge region is from CD8α or CD28 or a variant thereof, and/or

(ii) the first hinge region comprises an amino acid sequence selected from SEQ ID NOs: 3-4 and SEQ ID NOs: 34 or a variant thereof having 1-5 amino acid modifications.
The system of any one of claims 1 to 4, wherein the first transmembrane domain is different from the second transmembrance domain.
The system of any one of claims 1 to 5, wherein:

(i) the first transmembrane domain is from CD8α or CD28 or a vriant thereof, and/or

(ii) the first transmembrane domain comprises an amino acid sequence selected from SEQ ID NOs: 5-8 and SEQ ID NOs: 35 or a variant thereof having 1-5 amino acid modifications.
The system of any one of claims 1 to 6, wherein the first epitope is different from the second epitope.
The system of any one of claims 1 to 7, wherein the first epitope is present on a first antigen and the second epitope is present on a second antigen.
The system of any one of claims 1 to 8, wherein the first co-stimulatory domain and the second co-stimulatory domain each is independently selected from a group consisting of a signaling domain of a MHC class I molecule, a TNF receptor protein, an immunoglobulin-like protein, a cytokine receptor, an integrin, a signaling lymphocytic activation molecule (SLAM protein) , an activating NK cell receptor, or a Toll ligand receptor.
The system of any one of claims 1 to 9, wherein the first co-stimulatory domain and the second co-stimulatory domain each is independently a signaling domain of a molecule selected from: 2B4/CD244/SLAMF4, 4-1BB/TNFSF9/CD137, B7-1/CD80, B7-2/CD86, B7-H1/PD-L1, B7-H2, B7-H3, B7-H4, B7-H6, B7-H7, BAFF-R/TNFRSF13C, BAFF/BLyS/TNFSF13B, BLAME/SLAMF8, BTLA/CD272, CD100 (SEMA4D) , CD103, CD11a, CD11b, CD11c, CD11d, CD150, CD160 (BY55) , CD18, CD19, CD2, CD200, CD229/SLAMF3, CD27 Ligand/TNFSF7, CD27/TNFRSF7, CD28, CD29, CD2F-10/SLAMF9, CD30 Ligand/TNFSF8, CD30/TNFRSF8, CD300a/LMIR1, CD4, CD40 Ligand/TNFSF5, CD40/TNFRSF5, CD48/SLAMF2, CD49a, CD49D, CD49f, CD53, CD58/LFA-3, CD69, CD7, CD8 α, CD8 β, CD82/Kai-1, CD84/SLAMF5, CD90/Thy1, CD96, CDS, CEACAM1, CRACC/SLAMF7, CRTAM, CTLA-4, DAP12, Dectin-1/CLEC7A, DNAM1 (CD226) , DPPIV/CD26, DR3/TNFRSF25, EphB6, GADS, Gi24/VISTA/B7-H5, GITR Ligand/TNFSF18, GITR/TNFRSF18, HLA Class I, HLA-DR, HVEM/TNFRSF14, IA4, ICAM-1, ICOS/CD278, Ikaros, IL2R β, IL2R γ, IL7R α, Integrin α4/CD49d, Integrin α4β1, Integrin α4β7/LPAM-1, IPO-3, ITGA4, ITGA6, ITGAD, ITGAE, ITGAL, ITGAM, ITGAX, ITGB1, ITGB2, ITGB7, KIRDS2, LAG-3, LAT, LIGHT/TNFSF14, LTBR, Ly108, Ly9 (CD229) , lymphocyte function associated antigen-1 (LFA-1) , Lymphotoxin-α/TNF-β, NKG2C, NKG2D, NKp30, NKp44, NKp46, NKp80 (KLRF1) , NTB-A/SLAMF6, OX40 Ligand/TNFSF4, OX40/TNFRSF4, PAG/Cbp, PD-1, PDCD6, PD-L2/B7-DC, PSGL1, RELT/TNFRSF19L, SELPLG (CD162) , SLAM (SLAMF1) , SLAM/CD150, SLAMF4 (CD244) , SLAMF6 (NTB-A) , SLAMF7, SLP-76, TACI/TNFRSF13B, TCL1A, TCL1B, TIM-1/KIM-1/HAVCR, TIM-4, TL1A/TNFSF15, TNF RII/TNFRSF1B, TNF-α, TRANCE/RANKL, TSLP, TSLP R, VLA1, and VLA-6.
The system of any one of claims 1 to 10, wherein the first extracellular domain and/or the second extracellular domain comprises a Fab, a Fab’, a F (ab’) ₂, an Fv, a single-chain Fv (scFv) , minibody, a diabody, a single-domain antibody, a light chain variable domain (VL) , or a variable domain (V _HH) of camelid antibody.
The system of any one of claims 1 to 11, wherein the first epitope and/or the second epitope is present on a cell surface antigen.
The system of claim 12, wherein the cell surface antigen is selected from a group consisting of tumor associated antigens, tyrosine kinase receptors, serine kinase receptors, and G-protein coupled receptors.
The system of any one of claims 1 to 11, wherein the first epitope and/or the second epitope is present on a universal antigen.
The system of any one of claims 1 to 11, wherein the first epitope and/or the second epitope is present on a neoantigen.
The system of any one of claims 1 to 11, wherein the first epitope and/or the second epitope is a neoepitope.
The system of any one of claims 1 to 11, wherein the first epitope and/or the second epitope is present on a tumor associated antigen.
The system of claim 17, wherein the tumor associated antigen is selected from the group consisting of: 707-AP, a biotinylated molecule, a-Actinin-4, abl-bcr alb-b3 (b2a2) , abl-bcr alb-b4 (b3a2) , adipophilin, AFP, AIM-2, Annexin II, ART-4, BAGE, BCMA, b-Catenin, bcr-abl, bcr-abl p190 (e1a2) , bcr-abl p210 (b2a2) , bcr-abl p210 (b3a2) , BING-4, CA-125, CAG-3, CAIX, CAMEL, Caspase-8, CD171, CD19, CD20, CD22, CD23, CD24, CD30, CD33, CD38, CD44v7/8, CD70, CD123, CD133, CDC27, CD276, CDK-4, CEA, CLCA2, CLL-1, CTAG1B, Cyp-B, DAM-10, DAM-6, DEK-CAN, DLL3, EGFR, EGFRvIII, EGP-2, EGP-40, ELF2, Ep-CAM, EphA2, EphA3, erb-B2, erb-B3, erb-B4, ES-ESO-1a, ETV6/AML, FAP, FBP, fetal acetylcholine receptor, FGF-5, FN, FR-α, G250, GAGE-1, GAGE-2, GAGE-3, GAGE-4, GAGE-5, GAGE-6, GAGE-7B, GAGE-8, GD2, GD3, GnT-V, Gp100, gp75, GPA33, GPC3, GPC2, GUCY2C, Her-2, HLA-A*0201-R170I, HMW-MAA, HSP70-2 M, HST-2 (FGF6) , HST-2/neu, hTERT, iCE, IL-11Rα, IL-13Rα2, KDR, KIAA0205, K-RAS, L1-cell adhesion molecule, LAGE-1, LDLR/FUT, Lewis Y, L1-CAM, MAGE-1, MAGE-10, MAGE-12, MAGE-2, MAGE-3, MAGE-4, MAGE-6, MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A6, MAGE-B1, MAGE-B2, Malic enzyme, Mammaglobin-A, MART-1/Melan-A, MART-2, MC1R, M-CSF, mesothelin, MUC1, MUC16, MUC2, MUM-1, MUM-2, MUM-3, Myosin, NA88-A, Neo-PAP, Nectin-4, NKG2D, NPM/ALK, N-RAS, NY-ESO-1, OA1, OGT, oncofetal antigen (h5T4) , OS-9, P polypeptide, P15, P53, PRAME, PSA, PSCA, PSMA, PTPRK, RAGE, ROR1, RU1, RU2, SART-1, SART-2, SART-3, SOX10, SSX-2, Survivin, Survivin-2B, SYT/SSX, TAG-72, TEL/AML1, TGFaRII, TGFbRII, TP1, TRAG-3, TRG, TROP-2, TRP-1, TRP-2, TRP-2/INT2, TRP-2-6b, Tyrosinase, VEGF-R2, WT1, α-folate receptor, and κ-light chain.
The system of any one of claims 1 to 11, wherein the first epitope and/or the second epitope is present on an immune checkpoint receptor or immune checkpoint receptor ligand.
The system of claim 19, wherein the immune checkpoint receptor or immune checkpoint receptor ligand is PD-1, PD-L1, PD-L2, CTLA-4, TIM-3, LAG3, TIGIT, BLTA, CD47 or CD40.
The system of any one of claims 1 to 11, wherein the first epitope and/or the second epitope is present on a cytokine or a cytokine receptor.
The system of claim 21, wherein the cytokine or cytokine receptor is CCR2b, CXCR2 (CXCL1 receptor) , CCR4 (CCL17 receptor) , Gro-a, IL-2, IL-7, IL-15, IL-21, IL-12, Heparanase, CD137L, LEM, Bcl-2, CCL17, CCL19 or CCL2.
The system of any one of claims 1 to 11, wherein the first epitope and/or the second epitope is present on an antigen presented by a major histocompatibility complex (MHC) .
The system of claim 23, wherein the MHC is HLA class 1, or wherein the MHC is HLA class 2.
The system of any one of claims 1 to 24, wherein the system comprises a polypeptide comprising the chimeric co-stimulatory receptor and the CAR linked via a self-cleavable peptide linker.
A host cell expressing the system of any one of claims 1 to 25.
The host cell of claim 26, wherein the host cell is an immune cell.
The host cell of claim 27, wherein the immune cell is a lymphocyte or a myeloid cell.
The host cell of claim 28, wherein the lymphocyte is a T cell, a natural killer cell, or the myeloid cell is a monocyte, a macrophage, a granulocyte or a dendritic cell.
The host cell of claim 29, wherein the T cell is an αβ T cell or a γδ T cell.
A composition comprising one or more polynucleotides that encodes:

(a) a chimeric co-stimulatory receptor comprising (i) a first extracelluar domain capable of binding to a first epitope, (ii) a first transmembrane domain, and (iii) a first intracellular domain comprising a first co-stimulatory domain devoid of a signaling domain of CD3 zeta; and

(b) a CAR comprising (i) a second extracellular domain capable of binding to a second epitope, (ii) a second transmembrane domain, and (iii) a second intracellular domain comprising a signaling domain and a second co-stimulatory domain, wherein optionally the second intracellular domain further comprises a third co-stimulatory domain.
A method for making a CAR-T cell, comprising introducing into a T cell the composition of claim 31.
A CAR-T cell produced according to the method of claim 32.
A CAR-T cell expressing:

(a) a chimeric co-stimulatory receptor comprising (i) a first extracelluar domain capable of binding to a first epitope, (ii) a first transmembrane domain, and (iii) a first intracellular domain comprising a first co-stimulatory domain devoid of a signaling domain of CD3 zeta; and

(b) a CAR comprising (i) a second extracellular domain capable of binding to a second epitope, (ii) a second transmembrane domain, and (iii) a second intracellular domain comprising a signaling domain and a second co-stimulatory domain, wherein optionally the second intracellular domain further comprises a third co-stimulatory domain.
The CAR-T cell of claim 34, wherein the chimeric co-stimulatory receptor further comprises a first hinge region and the CAR further comprises a second hinge region.
The CAR-T cell of claim 35, wherein first hinge region is different from the second hinge region.
The CAR-T cell of any one of claims 35 to 36, wherein

(i) the first hinge region is from CD8α or CD28 or a variant thereof, and/or

(ii) the first hinge region comprising an amino acid sequence selected from SEQ ID NOs: 3-4 and SEQ ID NOs: 34 or a variant thereof having 1-5 amino acid modifications.
The CAR-T cell of any one of claims 34 to 37, wherein the first transmembrane domain is different from the second transmembrance domain.
The CAR-T cell of any one of claims 34 to 38, wherein

(i) the first transmembrane domain is from CD8α or CD28 or a variant thereof, and/or

(ii) the first transmembrane domain comprising an amino acid sequence selected from SEQ ID NOs: 5-8 and SEQ ID NOs: 35 or a variant thereof having 1-5 amino acid modifications.
The CAR-T cell of any one of claims 34 to 39, wherein the first epitope is different from the second epitope.
The CAR-T cell of any one of claims 34 to 40, wherein the first epitope is present on a first antigen and the second epitope is present on a second antigen.
The CAR-T cell of any one of claims 34 to 41, wherein the first co-stimulatory domain and the second co-stimulatory domain each is independently selected from a group consisting of a signaling domain of a MHC class I molecule, a TNF receptor protein, an immunoglobulin-like protein, a cytokine receptor, an integrin, a signaling lymphocytic activation molecule (SLAM protein) , an activating NK cell receptor, or a Toll ligand receptor.
The CAR-T cell of any one of claims 34 to 42, wherein the first co-stimulatory domain and the second co-stimulatory domain each is independently a signaling domain of a molecule selected from: 2B4/CD244/SLAMF4, 4-1BB/TNFSF9/CD137, B7-1/CD80, B7-2/CD86, B7-H1/PD-L1, B7-H2, B7-H3, B7-H4, B7-H6, B7-H7, BAFF-R/TNFRSF13C, BAFF/BLyS/TNFSF13B, BLAME/SLAMF8, BTLA/CD272, CD100 (SEMA4D) , CD103, CD11a, CD11b, CD11c, CD11d, CD150, CD160 (BY55) , CD18, CD19, CD2, CD200, CD229/SLAMF3, CD27 Ligand/TNFSF7, CD27/TNFRSF7, CD28, CD29, CD2F-10/SLAMF9, CD30 Ligand/TNFSF8, CD30/TNFRSF8, CD300a/LMIR1, CD4, CD40 Ligand/TNFSF5, CD40/TNFRSF5, CD48/SLAMF2, CD49a, CD49D, CD49f, CD53, CD58/LFA-3, CD69, CD7, CD8 α, CD8 β, CD82/Kai-1, CD84/SLAMF5, CD90/Thy1, CD96, CDS, CEACAM1, CRACC/SLAMF7, CRTAM, CTLA-4, DAP12, Dectin-1/CLEC7A, DNAM1 (CD226) , DPPIV/CD26, DR3/TNFRSF25, EphB6, GADS, Gi24/VISTA/B7-H5, GITR Ligand/TNFSF18, GITR/TNFRSF18, HLA Class I, HLA-DR, HVEM/TNFRSF14, IA4, ICAM-1, ICOS/CD278, Ikaros, IL2R β, IL2R γ, IL7R α, Integrin α4/CD49d, Integrin α4β1, Integrin α4β7/LPAM-1, IPO-3, ITGA4, ITGA6, ITGAD, ITGAE, ITGAL, ITGAM, ITGAX, ITGB1, ITGB2, ITGB7, KIRDS2, LAG-3, LAT, LIGHT/TNFSF14, LTBR, Ly108, Ly9 (CD229) , lymphocyte function associated antigen-1 (LFA-1) , Lymphotoxin-α/TNF-β, NKG2C, NKG2D, NKp30, NKp44, NKp46, NKp80 (KLRF1) , NTB-A/SLAMF6, OX40 Ligand/TNFSF4, OX40/TNFRSF4, PAG/Cbp, PD-1, PDCD6, PD-L2/B7-DC, PSGL1, RELT/TNFRSF19L, SELPLG (CD162) , SLAM (SLAMF1) , SLAM/CD150, SLAMF4 (CD244) , SLAMF6 (NTB-A) , SLAMF7, SLP-76, TACI/TNFRSF13B, TCL1A, TCL1B, TIM-1/KIM-1/HAVCR, TIM-4, TL1A/TNFSF15, TNF RII/TNFRSF1B, TNF-α, TRANCE/RANKL, TSLP, TSLP R, VLA-1, and VLA-6.
The CAR-T cell of any one of claims 34 to 43, wherein the first extracellular domain and/or the second extracellular domain comprises a Fab, a Fab’, a F (ab’) ₂, an Fv, a single-chain Fv (scFv) , minibody, a diabody, a single-domain antibody, a light chain variable domain (VL) , or a variable domain (V _HH) of camelid antibody.
The CAR-T cell of any one of claims 34 to 44, wherein the first epitope and/or the second epitope is present on a cell surface antigen.
The CAR-T cell of claim 45, wherein the cell surface antigen is selected from a group consisting of tumor associated antigens, tyrosine kinase receptors, serine kinase receptors, and G-protein coupled receptors.
The CAR-T cell of any one of claims 34 to 44, wherein the first epitope and/or the second epitope is present on a universal antigen.
The CAR-T cell of any one of claims 34 to 44, wherein the first epitope and/or the second epitope is present on a neoantigen.
The CAR-T cell of any one of claims 34 to 44, wherein the first epitope and/or the second epitope is a neoepitope.
The CAR-T cell of any one of claims 34 to 44, wherein the first epitope and/or the second epitope is present on a tumor associated antigen.
The CAR-T cell of claim 50, wherein the tumor associated antigen is selected from the group consisting of: 707-AP, a biotinylated molecule, a-Actinin-4, abl-bcr alb-b3 (b2a2) , abl-bcr alb-b4 (b3a2) , adipophilin, AFP, AIM-2, Annexin II, ART-4, BAGE, BCMA, b-Catenin, bcr-abl, bcr-abl p190 (e1a2) , bcr-abl p210 (b2a2) , bcr-abl p210 (b3a2) , BING-4, CA-125, CAG-3, CAIX, CAMEL, Caspase-8, CD171, CD19, CD20, CD22, CD23, CD24, CD30, CD33, CD38, CD44v7/8, CD70, CD123, CD133, CDC27, CD276, CDK-4, CEA, CLCA2, CLL-1, CTAG1B, Cyp-B, DAM-10, DAM-6, DEK-CAN, DLL3, EGFR, EGFRvIII, EGP-2, EGP-40, ELF2, Ep-CAM, EphA2, EphA3, erb-B2, erb-B3, erb-B4, ES-ESO-1a, ETV6/AML, FAP, FBP, fetal acetylcholine receptor, FGF-5, FN, FR-α, G250, GAGE-1, GAGE-2, GAGE-3, GAGE-4, GAGE-5, GAGE-6, GAGE-7B, GAGE-8, GD2, GD3, GnT-V, Gp100, gp75, GPA33, GPC3, GPC2, GUCY2C, Her-2, HLA-A*0201-R170I, HMW-MAA, HSP70-2 M, HST-2 (FGF6) , HST-2/neu, hTERT, iCE, IL-11Rα, IL-13Rα2, KDR, KIAA0205, K-RAS, L1-cell adhesion molecule, LAGE-1, LDLR/FUT, Lewis Y, L1-CAM, MAGE-1, MAGE-10, MAGE-12, MAGE-2, MAGE-3, MAGE-4, MAGE-6, MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A6, MAGE-B1, MAGE-B2, Malic enzyme, Mammaglobin-A, MART-1/Melan-A, MART-2, MC1R, M-CSF, mesothelin, MUC1, MUC16, MUC2, MUM-1, MUM-2, MUM-3, Myosin, NA88-A, Neo-PAP, Nectin-4, NKG2D, NPM/ALK, N-RAS, NY-ESO-1, OA1, OGT, oncofetal antigen (h5T4) , OS-9, P polypeptide, P15, P53, PRAME, PSA, PSCA, PSMA, PTPRK, RAGE, ROR1, RU1, RU2, SART-1, SART-2, SART-3, SOX10, SSX-2, Survivin, Survivin-2B, SYT/SSX, TAG-72, TEL/AML1, TGFaRII, TGFbRII, TP1, TRAG-3, TRG, TROP-2, TRP-1, TRP-2, TRP-2/INT2, TRP-2-6b, Tyrosinase, VEGF-R2, WT1, α-folate receptor, and κ-light chain.
The CAR-T cell of any one of claims 34 to 44, wherein the first epitope and/or the second epitope is present on an immune checkpoint receptor or immune checkpoint receptor ligand.
The CAR-T cell of claim 52, wherein the immune checkpoint receptor or immune checkpoint receptor ligand is PD-1, PD-L1, PD-L2, CTLA-4, TIM-3, LAG3, TIGIT, BLTA, CD47 or CD40.
The CAR-T cell of any one of claims 34 to 44, wherein the first epitope and/or the second epitope is present on a cytokine or a cytokine receptor.
The CAR-T cell of claim 54, wherein the cytokine or cytokine receptor is CCR2b, CXCR2 (CXCL1 receptor) , CCR4 (CCL17 receptor) , Gro-a, IL-2, IL-7, IL-15, IL-21, IL-12, Heparanase, CD137L, LEM, Bcl-2, CCL17, CCL19 or CCL2.
The CAR-T cell of any one of claims 34 to 44, wherein the first epitope and/or the second epitope is present on an antigen presented by a major histocompatibility complex (MHC) .
The CAR-T cell of claim 56, wherein the MHC is HLA class 1.
The CAR-T cell of claim 56, wherein the MHC is HLA class 2.
A pharmaceutical composition, comprising the host cell of any one of claims 26-30 or the CAR-T cell of any one of claims 33 to 58, and a pharmaceutically acceptable excipient.
A method for treating a disease or disorder in a subject comprising administering to the subject a therapeutically effective amount of the host cell of any one of claims 26-30, the CAR-T cell of any one of claims 33 to 58, or the pharmaceutical composition of claim 59.
The method of claim 60, wherein the disease or disorder is cancer.
The method of claim 61, wherein the cancer is blood cancer.
The method of claim 61, wherein the cancer is solid tumor cancer.
The method of any one of claims 60 to 63, wherein the subject is a human subject in need thereof.
A method of inducing activity of an immune cell, comprising:

(a) expressing a chimeric co-stimulatory receptor comprising (i) a first extracelluar domain capable of binding to a first epitope, (ii) a first transmembrane domain, and (iii) a first intracellular domain comprising a first co-stimulatory domain devoid of a signaling domain of CD3 zeta;

(b) expressing a CAR comprising (i) a second extracellular domain capable of binding to a second epitope, (ii) a second transmembrane domain, and (iii) a second intracellular domain comprising a signaling domain and a second co-stimulatory domain, wherein optionally the second intracellular domain further comprises a third co-stimulatory domain; and

(c) contacting a target cell with the immune cell.
The method of claim 65, wherein the target cell is a cancer cell.
The method of claim 65 or 66, wherein the target cell is a hematopoietic cell.
The method of claim 65 or 66, wherein the target cell is a solid tumor cell.
The method of claim 65 or 66, wherein the target cell is a cell identified in one or more of heart, blood vessels, salivary gland, esophagus, stomach, liver, gallbladder, pancreas, intestine, colon, rectum, anus, endocrine gland, adrenal gland, kidney, ureter, bladder, lymph node, tonsils, adenoid, thymus, spleen, skin, muscle, brain, spinal cord, nerve, ovary, fallopian tube, uterus, vagina, mammary gland, testes, prostate, penis, pharynx, larynx, trachea, bronchi, lung, diaphragm, cartilage, ligaments, and tendon.
The method of any one of claims 65 to 69, wherein the immune cell is a lymphocyte or a myeloid cell.
The method of claim 70, wherein the lymphocyte is a T cell, a natural killer cell, or the myeloid cell is a monocyte, a macrophage, a granulocyte or a dendritic cell.
The method of claim 71, wherein the T cell is an αβ T cell or a γδ T cell.
A system for inducing activity of an immune cell, comprising:

(a) a chimeric co-stimulatory receptor comprising a first antigen binding domain which exhibits specific binding to a first epitope, a transmembrane domain, and an intracellular signaling domain devoid of a signaling domain of CD3 zeta; and

(b) a modified or an unmodified T cell receptor (TCR) complex comprising a second antigen binding domain that exhibits specific binding to a second epitope, wherein the TCR comprises an alpha chain and/or a beta chain of a T cell receptor.
The system of claim 73, wherein binding of the first antigen binding domain to the first epitope, and/or binding of the second antigen binding domain to the second epitope activates an immune cell activity of an immune cell expressing the system.
The system of claim 73, wherein two or more antigen binding domains are linked to, optionally in tandem, (i) at least one TCR chain selected from an alpha chain and a beta chain of a T cell receptor, (ii) an epsilon chain, a delta chain, and/or a gamma chain of cluster of differentiation 3 (CD3) , (iii) a CD3 zeta chain, and wherein binding of the two more antigen binding domains to their respective epitopes activates an immune cell activity of an immune cell expressing the system.
The system of claim 74 or 75, wherein the immune cell activity is selected from the group consisting of: clonal expansion of the immune cell; cytokine release by the immune cell; cytotoxicity of the immune cell; proliferation of the immune cell; differentiation, dedifferentiation or transdifferentiation of the immune cell; movement and/or trafficking of the immune cell; exhaustion and/or reactivation of the immune cell; and release of other intercellular molecules, metabolites, chemical compounds, or combinations thereof by the immune cell.
The system of any one of claims 73 to 76, wherein the first epitope and the second epitope are the same.
The system of any one of claims 73 to 76, wherein the first epitope and the second epitope are different.
The system of any one of claims 73 to 78, wherein the first antigen binding domain and the second antigen binding domain comprise the same amino acid sequence.
The system of any one of claim 73 to 78, wherein the first antigen binding domain and the second antigen binding domain comprise different amino acid sequences.
The system of any one of claim 73 to 80, wherein the second antigen binding domain comprises a heterologous sequence exhibiting binding to the second epitope.
The system of any one of claims 73 to 81, wherein the modified or an unmodified TCR comprises a third antigen binding domain linked to: (i) the second antigen binding domain, (ii) the alpha chain and/or the beta chain of a T cell receptor, (iii) the epsilon chain, the delta chain, and/or the gamma chain of cluster of differentiation 3 (CD3) , or (iv) the CD3 zeta chain.
The system of any one of claims 73 to 82, wherein the intracellular signaling domain of the chimeric co-stimulatory receptor is devoid of an immunoreceptor tyrosine-based activation motif (ITAM) .
The system of any one of claims 73 to 83, wherein the chimeric co-stimulatory receptor further comprises a co-stimulatory domain.
The system of claim 84, wherein the co-stimulatory domain comprises a signaling domain of a MHC class I molecule, a TNF receptor protein, an immunoglobulin-like protein, a cytokine receptor, an integrin, a signaling lymphocytic activation molecule (SLAM protein) , an activating NK cell receptor, or a Toll ligand receptor.
The system of claim 85, wherein the co-stimulatory domain comprises a signaling domain of a molecule selected from: 2B4/CD244/SLAMF4, 4-1BB/TNFSF9/CD137, B7-1/CD80, B7-2/CD86, B7-H1/PD-L1, B7-H2, B7-H3, B7-H4, B7-H6, B7-H7, BAFF-R/TNFRSF13C, BAFF/BLyS/TNFSF13B, BLAME/SLAMF8, BTLA/CD272, CD100 (SEMA4D) , CD103, CD11a, CD11b, CD11c, CD11d, CD150, CD160 (BY55) , CD18, CD19, CD2, CD200, CD229/SLAMF3, CD27 Ligand/TNFSF7, CD27/TNFRSF7, CD28, CD29, CD2F-10/SLAMF9, CD30 Ligand/TNFSF8, CD30/TNFRSF8, CD300a/LMIR1, CD4, CD40 Ligand/TNFSF5, CD40/TNFRSF5, CD48/SLAMF2, CD49a, CD49D, CD49f, CD53, CD58/LFA-3, CD69, CD7, CD8 α, CD8 β, CD82/Kai-1, CD84/SLAMF5, CD90/Thy1, CD96, CDS, CEACAM1, CRACC/SLAMF7, CRTAM, CTLA-4, DAP12, Dectin-1/CLEC7A, DNAM1 (CD226) , DPPIV/CD26, DR3/TNFRSF25, EphB6, GADS, Gi24/VISTA/B7-H5, GITR Ligand/TNFSF18, GITR/TNFRSF18, HLA Class I, HLA-DR, HVEM/TNFRSF14, IA4, ICAM-1, ICOS/CD278, Ikaros, IL2R β, IL2R γ, IL7R α, Integrin α4/CD49d, Integrin α4β1, Integrin α4β7/LPAM-1, IPO-3, ITGA4, ITGA6, ITGAD, ITGAE, ITGAL, ITGAM, ITGAX, ITGB1, ITGB2, ITGB7, KIRDS2, LAG-3, LAT, LIGHT/TNFSF14, LTBR, Ly108, Ly9 (CD229) , lymphocyte function associated antigen-1 (LFA-1) , Lymphotoxin-α/TNF-β, NKG2C, NKG2D, NKp30, NKp44, NKp46, NKp80 (KLRF1) , NTB-A/SLAMF6, OX40 Ligand/TNFSF4, OX40/TNFRSF4, PAG/Cbp, PD-1, PDCD6, PD-L2/B7-DC, PSGL1, RELT/TNFRSF19L, SELPLG (CD162) , SLAM (SLAMF1) , SLAM/CD150, SLAMF4 (CD244) , SLAMF6 (NTB-A) , SLAMF7, SLP-76, TACI/TNFRSF13B, TCL1A, TCL1B, TIM-1/KIM-1/HAVCR, TIM-4, TL1A/TNFSF15, TNF RII/TNFRSF1B, TNF-α, TRANCE/RANKL, TSLP, TSLP R, VLA1, and VLA-6.
The system of any one of claims 73 to 86, wherein the first antigen binding domain and/or the second antigen binding domain comprises a Fab, a Fab’, a F (ab’) ₂, an Fv, a single-chain Fv (scFv) , minibody, a diabody, a single-domain antibody, a light chain variable domain (VL) , or a variable domain (V _HH) of camelid antibody.
The system of any one of claims 73 to 87, wherein the first antigen binding domain and/or the second antigen binding domain comprises a receptor.
The system of any one of claims 73 to 87, wherein the first antigen binding domain and/or the second antigen binding domain comprises a ligand for a receptor.
The system of any one of claims 73 to 89, wherein the first epitope and the second epitope are present on different antigens.
The system of any one of claims 73 to 89, wherein the first epitope and the second epitope are present on a common antigen.
The system of any one of claims 73 to 89, wherein the first epitope and/or the second epitope are present on one or more cell surface antigens.
The system of claim 92, wherein the one or more cell surface antigens are tumor associated antigens, tyrosine kinase receptors, serine kinase receptors, and G-protein coupled receptors.
The system of any one of claims 73 to 89, wherein the first epitope and/or the second epitope is present on a universal antigen.
The system of any one of claims 73 to 89, wherein the first epitope and/or the second epitope is present on a neoantigen.
The system of any one of claims 73 to 89, wherein the first epitope and/or the second epitope is a neoepitope.
The system of any one of claims 73 to 89, wherein the first epitope and/or the second epitope is present on a tumor-associated antigen.
The system of claim 97, wherein the tumor-associated antigen is selected from the group consisting of: 707-AP, a biotinylated molecule, a-Actinin-4, abl-bcr alb-b3 (b2a2) , abl-bcr alb-b4 (b3a2) , adipophilin, AFP, AIM-2, Annexin II, ART-4, BAGE, BCMA, b-Catenin, bcr-abl, bcr-abl p190 (e1a2) , bcr-abl p210 (b2a2) , bcr-abl p210 (b3a2) , BING-4, CA-125, CAG-3, CAIX, CAMEL, Caspase-8, CD171, CD19, CD20, CD22, CD23, CD24, CD30, CD33, CD38, CD44v7/8, CD70, CD123, CD133, CDC27, CD276, CDK-4, CEA, CLCA2, CLL-1, CTAG1B, Cyp-B, DAM-10, DAM-6, DEK-CAN, DLL3, EGFR, EGFRvIII, EGP-2, EGP-40, ELF2, Ep-CAM, EphA2, EphA3, erb-B2, erb-B3, erb-B4, ES-ESO-1a, ETV6/AML, FAP, FBP, fetal acetylcholine receptor, FGF-5, FN, FR-α, G250, GAGE-1, GAGE-2, GAGE-3, GAGE-4, GAGE-5, GAGE-6, GAGE-7B, GAGE-8, GD2, GD3, GnT-V, Gp100, gp75, GPA33, GPC3, GPC2, GUCY2C, Her-2, HLA-A*0201-R170I, HMW-MAA, HSP70-2 M, HST-2 (FGF6) , HST-2/neu, hTERT, iCE, IL-11Rα, IL-13Rα2, KDR, KIAA0205, K-RAS, L1-cell adhesion molecule, LAGE-1, LDLR/FUT, Lewis Y, L1-CAM, MAGE-1, MAGE-10, MAGE-12, MAGE-2, MAGE-3, MAGE-4, MAGE-6, MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A6, MAGE-B1, MAGE-B2, Malic enzyme, Mammaglobin-A, MART-1/Melan-A, MART-2, MC1R, M-CSF, mesothelin, MUC1, MUC16, MUC2, MUM-1, MUM-2, MUM-3, Myosin, NA88-A, Neo-PAP, Nectin-4, NKG2D, NPM/ALK, N-RAS, NY-ESO-1, OA1, OGT, oncofetal antigen (h5T4) , OS-9, P polypeptide, P15, P53, PRAME, PSA, PSCA, PSMA, PTPRK, RAGE, ROR1, RU1, RU2, SART-1, SART-2, SART-3, SOX10, SSX-2, Survivin, Survivin-2B, SYT/SSX, TAG-72, TEL/AML1, TGFaRII, TGFbRII, TP1, TRAG-3, TRG, TROP-2, TRP-1, TRP-2, TRP-2/INT2, TRP-2-6b, Tyrosinase, VEGF-R2, WT1, α-folate receptor, and κ-light chain.
The system of any one of claims 73 to 89, wherein the first epitope and/or the second epitope is present on an immune checkpoint receptor or immune checkpoint receptor ligand.
The system of claim 99, wherein the immune checkpoint receptor or immune checkpoint receptor ligand is PD-1, PD-L1, PD-L2, CTLA-4, TIM-3, LAG3, TIGIT, BLTA, CD47 or CD40.
The system of any one of claims 73 to 89, wherein the first epitope and/or the second epitope is present on a cytokine or a cytokine receptor.
The system of claim 101, wherein the cytokine or cytokine receptor is CCR2b, CXCR2 (CXCL1 receptor) , CCR4 (CCL17 receptor) , Gro-a, IL-2, IL-7, IL-15, IL-21, IL-12, Heparanase, CD137L, LEM, Bcl-2, CCL17, CCL19 or CCL2.
The system of any one of claims 73 to 89, wherein the first epitope and/or the second epitope is present on an antigen presented by a major histocompatibility complex (MHC) .
The system of claim 103, wherein the MHC is HLA class 1.
The system of claim 103, wherein the MHC is HLA class 2.
A host cell expressing the system of any one of claims 73 to 105.
The host cell of claim 106, wherein the host cell is an αβ T cell or a γδ T cell.
The host cell of claim 106 or claim 107, wherein the host cell exhibits specific binding to two antigens simultaneously present in a target cell.
An immune cell comprising a system of any one of claims 73 to 105.
The immune cell of claim 109, wherein the antigen binding domain linked to the chimeric co-stimulatory receptor primarily mediates interaction between the immune cell and a target cell, and the antigen binding domain linked to the TCR complex primarily mediates an immune cell activity when the interaction between the immune cell and the target cell takes place.
The immune cell of claim 110, wherein the immune cell activity is selected from the group consisting of: clonal expansion of the immune cell; cytokine release by the immune cell; cytotoxicity of the immune cell; proliferation of the immune cell; differentiation, dedifferentiation or transdifferentiation of the immune cell; movement and/or trafficking of the immune cell; exhaustion and/or reactivation of the immune cell; and release of other intercellular molecules, metabolites, chemical compounds, or combinations thereof by the immune cell.
The immune cell of any one of claims 109 to 111, wherein the immune cell is an αβ T cell or a γδ T cell.
A population of immune cells comprising an immune cell expressing a system of any one of claims 73 to 105.
The population of immune cells of claim 113, wherein the immune cells comprise αβ T cells and/or γδ T cell.
A method of inducing an activity of an immune cell, comprising: (a) expressing a system of any one of claims 73 to 105 in an immune cell; and (b) contacting a target cell with the immune cell.
The method of claim 115, wherein the target cell is a cancer cell.
The method of claim 115 or 116, wherein the target cell is a hematopoietic cell.
The method of claim 115 or 116, wherein the target cell is a solid tumor cell.
The method of claim 115 or 116, wherein the target cell is a cell identified in one or more of heart, blood vessels, salivary gland, esophagus, stomach, liver, gallbladder, pancreas, intestine, colon, rectum, anus, endocrine gland, adrenal gland, kidney, ureter, bladder, lymph node, tonsils, adenoid, thymus, spleen, skin, muscle, brain, spinal cord, nerve, ovary, fallopian tube, uterus, vagina, mammary gland, testes, prostate, penis, pharynx, larynx, trachea, bronchi, lung, diaphragm, cartilage, ligaments, and tendon.
The method of any one of claims 115 to 119, wherein the immune cell is an αβ T cell or a γδ T cell.
A composition comprising one or more polynucleotides that encodes:

(a) a chimeric co-stimulatory receptor comprising a first antigen binding domain which exhibits specific binding to a first epitope, a transmembrane domain, and an intracellular signaling domain devoid of a signaling domain of CD3 zeta; and

(b) a modified or an unmodified T cell receptor (TCR) complex comprising a second antigen binding domain that exhibits specific binding to a second epitope, wherein the TCR comprises an alpha chain and/or a beta chain of a T cell receptor.
A method of producing a modified immune cell, comprising introducing into an immune cell the composition of claim 121.
A pharmaceutical composition comprising the host cell, the immune cell, the population of immune cells of any one of claims 106-114 or the modified immune cell produced according to the method of claim 122, and a pharmaceutically acceptable excipient.
A method for treating a disease or disorder in a subject comprising administering to the subject a therapeutically effective amount of the host cell, the immune cell, the population of immue cells of any one of claims 106-114 or the modified immune cell produced according to the method of claim 122, or the pharmaceutical composition of claim 123.
The method of claim 124, wherein the disease or disorder is cancer.
The method of claim 125, wherein the cancer is blood cancer.
The method of claim 125, wherein the cancer is solid tumor cancer.
The method of any one of claims 124 to 127, wherein the subject is a human subject in need thereof.