WO2014099671A1

WO2014099671A1 - Chimeric antigen receptors and immune cells targeting b cell malignancies

Info

Publication number: WO2014099671A1
Application number: PCT/US2013/075075
Authority: WO
Inventors: Mitchell Howard FINER
Original assignee: Bluebird Bio, Inc.
Priority date: 2012-12-20
Filing date: 2013-12-13
Publication date: 2014-06-26
Also published as: US20150329640A1

Abstract

The disclosure describes genetically engineered CD37 specific redirected immune effector cells expressing a chimeric antigen receptor (CAR) protein comprising an antigen binding domain derived from an antibody, a single chain antibody or portion thereof that binds CD37; a hinge region; a transmembrane domain and an intracellular signaling domain derived from human CD3ζ or FcRϒ; and optionally one or more co- stimulatory intracellular signaling domains The invention includes nucleic acids, vectors and immune effector cells associated with the production of the CAR protein, as well as methods of treating B cell malignancies in humans by cellular immunotherapy.

Description

CHIMERIC ANTIGEN RECEPTORS AND IMMUNE CELLS

TARGETING B CELL MALIGNANCIES

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional

Application No. 61/780,687, filed March 13, 2013, and U.S. Provisional Application No.

61/740,120, filed December 20, 2012, which is incorporated by reference in its entirety.

STATEMENT REGARDING SEQUENCE LISTING

The Sequence Listing associated with this application is provided in text format in lieu of a paper copy, and is hereby incorporated by reference into the specification. The name of the text file containing the Sequence Listing is BLBD_023_02WO_ST25.txt. The text file is 63 KB, was created on December 13, 2013, and is being submitted electronically via EFS-Web.

BACKGROUND

Technical Field

The present invention relates to chimeric receptor genes suitable for genetically modifying immune effector cells, in particular T cells, natural killer cells (NK cells), CD1 restricted NKT cells and the mature immune effector cells derived from CD34⁺ fraction containing hematopoietic stem cells (HSCs), with chimeric antigen receptors (CARs) having an antigen binding domain with antibody-type specificity against CD37; expression vectors comprising said chimeric receptor genes, and T cells, NK cells and mature immune effector cells including neutrophils and macrophages derived from hematopoietic stem cells (HSCs) contained within the CD34+ population of cells in bone marrow, cord blood or mobilized peripheral blood transformed with said expression vectors. More particularly, the invention relates to the above compositions and methods for the treatment of B cell malignancies, such as chronic lymphocytic leukemia (CLL), B cell non-Hodgkin lymphoma (B cell NHL), hairy cell leukemia (HCL), Acute Lymphoblastic Leukemia (ALL) and lymphoplasmacytic lymphoma.

Description of the Related Art

Since the approval of chimeric anti-CD20 monoclonal antibody rituximab to treat hematologic malignancies, numerous other monoclonal antibodies have been studied as potential B cell therapies, including anti-CD19, anti-CD52, anti- CD22, anti-CD23, anti-CD80 and anti- HLA-DR antibodies. Recently, monoclonal antibodies targeting CD37 have been reported with enhanced antibody features such as improved effector function, target affinity and apoptotic signaling (Heider et al, Blood. 2011; 118:4159-4168). Preclinical studies thus far described in the anti-CD37 antibody reports, including other studied antibody therapeutics have revealed an obstacle to effectiveness, i.e., rapid elimination of therapeutic antibodies due to serum proteases and filtration at the glomerulus. In addition to pharmacokinetics, a major limitation of antibody- based therapies is limited penetration into the tumor site and expression levels of the target antigen on tumor cells.

Therefore, there remains a need to consider other alternative therapeutic strategies, including adoptive immunotherapy, as a treatment option that targets malignant B cells and selection of target antigens that are widely expressed at significant levels across a wide variety of B cell malignancies.

BRIEF SUMMARY

The present invention provides genetically modified immune effector cells comprising T lymphocytes, NK cells, NKT cells, mature immune effector cells including neutrophils, macrophages derived from hematopoietic stem cells (HSCs) contained within the CD34+ population of cells derived from cord blood, bone marrow or mobilized peripheral blood which upon administration in a subject differentiate into mature immune effector cells; said immune effector cells expressing murine, human or humanized CARs that redirect these effector cells to specifically bind to and kill CD37-expressing target cells.

In one embodiment, the CARs of the present invention comprise four functional domains: (1) a binding domain that binds the CD37 antigen and thereby targets the CAR expressing immune effector cell to a CD37 expressing target cell; (2) a hinge or spacer region that extends the binding domain away from the effector cell plasma membrane; (3) a transmembrane domain that anchors the CAR to the effector cell and links the binding domain to the intracellular signaling domain; and

(4) an intracellular domain comprising a signaling domain or domains, and optionally one or more co-stimulatory signaling domains.

In another embodiment, the invention relates to a nucleic acid or nucleic acid construct encoding a chimeric antigen receptor, the chimeric protein comprising several polypeptide portions: (1) a binding domain that binds CD37, e.g., an anti-CD37 antibody, or an antigen-binding fragment thereof (such as a scFv derived from a murine, human or humanized antibody that binds CD37); (2) a hinge or spacer region derived from CD8a, CD4, CD28 or CD7; (3) human CD3ζ, CD28, CD8a or CD4 transmembrane region and (4) a human CD3ζ or FcR γ intracellular signaling domain, and

(5) optionally one or more intracellular co-stimulatory signaling domains derived from a protein selected from the group consisting of CD28, CD137 (4-1BB), CD134 (OX40) and CD298 (ICOS).

In particular embodiments where the binding domain is a single chain antibody, the single chain antibody may be linked to part of the constant region of IgGl or IgG4. In certain embodiments the constant region of IgGl has a mutation at position 237. In one embodiment, the mutation is a G237A mutation (Hezareh et al., J. Virol. 2001; 75: 12161-12168).

In another embodiment, the invention relates to an immune effector cell or progenitor of an immune effector cell, comprising one or more of the CAR proteins described herein and a population of immune effector cells that have been modified to express one or more of the CAR proteins described herein. In one embodiment, the immune effector cells are T cells, NK cells, NKT cells, or those mature immune effector cells including neutrophils, macrophages arising from CAR-modified hematopoietic stem cells (HSC) within the CD34+ population of cells present in cord blood, bone marrow or mobilized peripheral blood.

In another embodiment, the invention relates to a method of making and expanding CD37- specific CAR immune effector cells which comprises introducing into immune effector cells, an expression vector containing a nucleic acid construct encoding a CD37-specific CAR as described herein, stimulating the cells with antibodies against CD3 and CD28 in the presence of IL-2, or tumor targets expressing CD37 antigen in the presence of IL-2, wherein the CAR immune effector proliferate in the presence of tumor expressing CD37 antigen and IL-2.

In another embodiment, the present invention relates to a vector comprising a nucleic acid encoding a CD37-speific CAR as described herein. In one embodiment, the vector is a viral vector, wherein the viral vector is selected from the group consisting of retrovirus, human HIV-1, Equine Infectious Anemia Virus (EIAV), Feline Immunodeficiency Virus (FIV) or human Foamy Virus. The present disclosure also provides methods to stably introduce and redirect immune effector cells by viral transduction. Other embodiments provide a variety of methods for genetically modifying a cell with a vector which comprises a nucleic acid encoding an anti-CD37 CAR as described herein. Such vectors and methods of genetically modifying cells (e.g., immune effector cells) include a variety of expression vectors and methods of introducing such vectors into cells, such as transfection, electroporation, transduction, gene gun, and the like. Thus, in another embodiment, the invention relates to a method of stably introducing and re-directing immune effector cells by electroporation using naked DNA or introduction of DNA using chemical transfection reagents such as lipofectamine (Invitrogen / Life Technologies, Carlsbad, CA) and related compounds known in the art such as PEI (polyethyleneimine, Sigma Aldrich Fine Chemicals, St. Louis, MO).

In another embodiment, the invention relates to methods of treating a human with a B cell malignancy comprising administering to a human diagnosed with said malignancy, a population of modified human immune effector cells or a population of progenitors of immune effector cells that upon administration can differentiate into immune effector cells, expressing the CARs described herein. In another embodiment, the invention relates to a method of treating a subject with a B cell malignancy comprising removing immune effector cells such as T, NK, NKT, or hematopoietic stem cells (HSCs) contained within the CD34+ population of cells in bone marrow, cord blood or mobilized peripheral blood from a subject diagnosed with said malignancy, introducing into said immune effector cells a vector comprising a nucleic acid encoding the CAR proteins described herein, and administering the population of said immune effector cells to the same subject.

In another embodiment, the invention relates to a method of treating a subject with a B cell malignancy comprising removing immune effector cells such as T, NK, NKT, introducing into said immune effector cells a vector comprising a nucleic acid encoding the CAR proteins described herein, and administering the population of said immune effector cells to the same subject.

In certain embodiments, the removed immune effector cells are not expanded before modifying with CAR expression vector. In other embodiments, CD34+ cells are pre-stimulated with at least one of the following cytokines, namely, FLT3 ligand, TPO (megakaryocyte growth and differentiation factor), SCF (stem cell factor), IL-3 and IL-6, followed by exposure to the viral vector prior to re-administration into a subject (Asheuer et al., PNAS, 2004; 101 : 3557-3562; Imren et al., J. Clin. Invest, 2004; 114: 953-962).

In particular embodiments, the B cell malignancies are chronic lymphocytic leukemia (CLL), B cell non-Hodgkin lymphoma (B cell NHL), hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL) and lymphoplasmacytic lymphoma. BRIEF DESCRIPTION OF THE FIGURES

The following description of the Figures comprises non-limiting examples that depict various embodiments that exemplify the present invention.

FIGURE 1 depicts the structure of embodiments of the CD37 CAR constructs. The signal peptide (SP), extracellular domain CD37 scFv, hinge, transmembrane (TM) and cytoplasmic signaling domains of 4-1BB (CD137), CD28, CD3ζ are identified.

FIGURE 2 depicts the construction of the lentiviral vector containing the CAR CD37-t construct.

FIGURE 3 depicts the construction of the lentiviral vector containing the CAR CD37-Z construct.

FIGURE 4 depicts the construction of the lentiviral vector containing the CAR CD37-BZ construct.

FIGURE 5 depicts the construction of the lentiviral vector containing the CAR CD37- 28Z construct.

FIGURE 6 depicts the construction of the lentiviral vector containing the CAR CD37- 28BZ construct. FIGURE 7 depicts the construction of the lentiviral vector containing the multiple cloning site of pBBl 12 under the control of the human Elongation Factor la promoter.

BRIEF DESCRIPTION OF THE SEQUENCE IDENTIFIERS

SEQ ID NO: l is the nucleic acid sequence encoding the CD37-BZ chimeric antigen receptor.

SEQ ID NO:2 is the nucleic acid sequence encoding the CD37-28Z chimeric antigen receptor.

SEQ ID NO:3 is the nucleic acid sequence encoding the CD37-28BZ chimeric antigen receptor.

SEQ ID NO:4 is the nucleic acid sequence encoding the CD37t chimeric antigen receptor.

SEQ ID NO:5 is the nucleic acid sequence encoding the CD37-Z chimeric antigen receptor. SEQ ID NO:6 is the nucleic acid sequence encoding the pBBl 12 EFla-GFP construct.

DETAILED DESCRIPTION

The practice of the present invention will employ, unless indicated specifically to the contrary, conventional methods of virology, immunology, microbiology, molecular biology and recombinant DNA techniques within the skill of the art, many of which are described below for the purpose of illustration. Such techniques are explained fully in the literature. See, e.g., Current Protocols in Molecular Biology or Current Protocols in Immunology, John Wiley & Sons, New York, N.Y.(2009); Ausubel et al, Short Protocols in Molecular Biology, 3^rd ed., Wiley & Sons, 1995; Sambrook and Russell, Molecular Cloning: A Laboratory Manual (3rd Edition, 2001); Maniatis et al. Molecular Cloning: A Laboratory Manual (1982); DNA Cloning: A Practical Approach, vol. I & II (D. Glover, ed.); Oligonucleotide Synthesis (N. Gait, ed., 1984); Nucleic Acid Hybridization (B. Hames & S. Higgins, eds., 1985); Transcription and Translation (B. Hames & S. Higgins, eds., 1984); Animal Cell Culture (R. Freshney, ed., 1986); Perbal, A Practical Guide to Molecular Cloning (1984) and other like references.

As used in this specification and the appended claims, the singular forms "a," "an" and "the" include plural references unless the content clearly dictates otherwise.

Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or integer or group of elements or integers but not the exclusion of any other element or integer or group of elements or integers.

Each embodiment in this specification is to be applied mutatis mutandis to every other embodiment unless expressly stated otherwise. Furthermore, when the term, "functionally equivalent," is applied to nucleic acids or polypeptides, it refers to fragments, variants and the like that have the same or similar activity as the reference nucleic acids or polypeptides.

Standard techniques may be used for recombinant DNA, oligonucleotide synthesis, and tissue culture and transformation (e.g., electroporation, lipofection). Enzymatic reactions and purification techniques may be performed according to manufacturer's specifications or as commonly accomplished in the art or as described herein. These and related techniques and procedures may be generally performed according to conventional methods well known in the art and as described in various general and more specific references that are cited and discussed throughout the present specification. Unless specific definitions are provided, the nomenclature utilized in connection with, and the laboratory procedures and techniques of, molecular biology, analytical chemistry, synthetic organic chemistry, and medicinal and pharmaceutical chemistry described herein are those well known and commonly used in the art. Standard techniques may be used for recombinant technology, molecular biological, microbiological, chemical syntheses, chemical analyses, pharmaceutical preparation, formulation, and delivery, and treatment of patients.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs.

Genetic approaches offer a potential means to enhance immune recognition and elimination of cancer cells. One promising strategy is to genetically engineer immune effector cells to express chimeric antigen receptors that redirect cytotoxicity toward tumor cells. These genetically engineered receptors referred to herein as chimeric antigen receptors (CARs) comprise an antigen- specific recognition domain that binds to a specific target antigen (also referred to as a binding domain). The binding domain is typically a single-chain antibody variable fragment (scFv), a tethered ligand or the extracellular domain of a co-receptor, fused to a transmembrane domain, which is linked, in turn, to a signaling domain, typically the signaling domain derived from CD3ζ or FcRy and optionally one or more co-stimulatory domains derived from a protein such as CD28, CD137 (also known as 4-lBB), CD134 (also known as OX40) and CD278 (also known as ICOS). Engagement of the antigen binding domain of the CAR with its target antigen on the surface of a target cell results in clustering of the CAR and delivers an activation stimulus to the CAR-containing cell. The main characteristic of CARs are their ability to redirect immune effector cell specificity, thereby triggering proliferation, cytokine production, phagocytosis or production of molecules that can mediate cell death of the target antigen expressing cell in a major histocompatibility (MHC) independent manner, exploiting the cell specific targeting abilities of monoclonal antibodies, soluble ligands or cell specific co-receptors. Although scFv-based CARs engineered to contain a signaling domain from CD3ζ or FcRy have been shown to deliver a potent signal for T cell activation and effector function, they are not sufficient to elicit signals that promote T cell survival and expansion in the absence of a concomitant co-stimulatory signal. A new generation of CARs containing a binding domain, a hinge, a transmembrane and the signaling domain derived from CD3ζ or FcRy together with one or more co-stimulatory signaling domains (e.g., intracellular co-stimulatory domains derived from CD28, CD137, CD134 and CD278) has been shown to more effectively direct antitumor activity as well as increased cytokine secretion, lytic activity, survival and proliferation in CAR expressing T cells in vitro, in animal models and cancer patients (Milone et al., Molecular Therapy, 2009; 17: 1453-1464; Zhong et al., Molecular Therapy, 2010; 18: 413-420; Carpenito et al., PNAS, 2009; 106:3360-3365).

One aspect of the CAR strategy described herein is the selection of target epitopes that are specifically or selectively expressed on the tumor cells of the target malignancy and are membrane epitopes not prone to shed or internalize from the cell surface.

The present invention is based in part on the finding that the binding domain of the

CARs described herein that binds to CD37 endows the CAR-expressing immune effector cell with unique properties directed to B cell malignancies that are not heretofore predicted by other CAR molecules targeting B cell tumor specific antigens. The CD37 antigen is a heavily glycosylated 40- to 52kDa glycoprotein and member of the tetraspanin transmembrane family of proteins (Schwartz-Albiez et al., Cancer. 1988; 140: 905-914). CD37 is expressed in cells progressing from pre-B to peripheral mature B cells and is absent on plasma cells (Moldenhauer, J. Biol. Regul. Homeost. Agents. 2000; 14: 281 -283). CD37 antigen is expressed at very low density on monocytes and granulocytes and absent on NK cells, platelets and erythrocytes (Link et al., J. Immunol. 1986; 137: 3013-3018). CD37 has modest internalization and shedding in transformed B cells expressing the antigen (Press et al, Cancer Res. 1989; 49: 4906-4912; Press et al., Blood. 1994; 83 : 1390-1397). Most significant is that CD37 expression has been detected on malignancies derived from peripheral mature B cells, such as B cell chronic lymphocyte leukemia (CLL), hairy cell leukemia (HCL) and B cell NHL (Belov et al., Cancer Res. 2001 ; 61 : 4483-4489). In addition, expression of CD37 is relatively high in CLL, B cell leukemia and lymphoma (Press et al., 1989; Press et al., 1994). One report on a CD37 IgGl- like antibody (scFv-hinge-CH2-CH3) revealed the antibody's ability to kill CD37-expressing B cells by direct apoptosis (mediated by CD37 ligation) and also by antibody dependent cell-mediated cytotoxicity (ADCC) in pre-clinical studies (Zhao et al., Blood. 2006; 110: 2569-2577) and phase 1 clinical trials in patients with relapsed refractory CLL (Andritsos et al., J. Clin. Oncol. 2009; 27(15s): Abstract 3017). A second study using a monoclonal antibody directed against CD37 confirmed the antibody's dual effector functions, namely ADCC and ligation-mediated apoptosis, against target Ramos Burkitt's lymphoma and CLL cells from patients (Heider et al., Blood. 201 1 ; 118: 4159-4168).

According to the present invention, CARs expressed on immune effector cells initiate target cell killing following binding to specific ligand expressed on the target cell. Such CAR- mediated death occurs because CAR ligation triggers immune effector cell activation, resulting in induction of effector cell signaling pathways (e.g. granule exocytosis, up-regulation of FasL and secretion of pro-inflammatory cytokines) that drive target cell apoptosis (Jenkins and Griffiths, Current Opinion In Immunology, 2010; 22: 308-313; de Saint Basile et al., Nature Reviews Immunology, 2010; 10: 568-579; Cullen et al., Cell Death and Differentiation, 2010; 17: 616- 623).

A novel CAR protein is provided herein that comprises a binding domain directed against CD37 (in certain embodiments this binding domain is constructed as an anti-CD37 scFv), a hinge region, a transmembrane domain, an intracellular domain comprising the signaling domain derived from CD3 ζ or FcRy, and optionally one or more co-stimulatory signaling domains that can further increase immune effector cell function and/or survival. The novel CD37 CAR is different from previously described CARs, in that it possesses an additional mechanism for killing target cells, namely CD37 ligation-mediated apoptosis. Binding of the CD37 CAR to CD37 on the relevant target cell directly triggers an endogenous pro-apoptotic pathway that results in target cell death. According to the present invention, the novel CD37 CAR expressed in an immune effector cell can kill CD 37 -expressing target cells, not only by immune effector cell activation-dependent pathways utilized by other CARs, but also by direct CD37 ligation-mediated apoptosis. Since CD37 is expressed on B cell tumors, tumor killing mediated by CD37 CAR is more efficient than that mediated by CAR recognizing alternative ligands on the same tumor target (e.g., CD20 and CD19) that are not capable of ligation-mediated apoptosis. Furthermore, since CD37 ligation-mediated apoptosis is independent of immune effector cell activation, the therapeutic killing activity mediated by CD37 CAR is likely to be maintained in an immune effector cell-suppressive tumor microenvironment, in contrast to previously described CARs.

According to the present invention, a bi-functional CAR expressed in an immune effector cell is capable of killing a target cell by two mechanisms: (i) immune effector cell mediated (e.g., T cell-mediated) and (ii) target ligand-mediated. Both T cell-mediated and target ligand- mediated cell death are initiated in response to binding of the CAR to its specific ligand on the target cell, (i) In the case of T cell-mediated killing, CAR-ligand binding initiates CAR signaling to the T cell, resulting in activation of a variety of T cell signaling pathways (a process termed T cell activation) that induce the T cell to produce or release proteins capable of inducing target cell apoptosis by various mechanisms. These T cell-mediated mechanisms include (but are not limited to) the transfer of intracellular cytotoxic granules from the T cell into the target cell, T cell secretion of pro-inflammatory cytokines that can induce target cell killing directly (or indirectly via recruitment of other killer effector cells), and up regulation of death receptor ligands {e.g. FasL) on the T cell surface that induce target cell apoptosis following binding to their cognate death receptor (e.g. Fas) on the target cell; (ii) In the case of target ligand-mediated killing, CAR- ligand binding initiates ligand-mediated signaling in the interior of the target cell, resulting in activation of endogenous killing pathways in the target cell {e.g. those involving apoptosis or necrosis). Unlike T cell-mediated killing, target ligand-mediated killing is independent of CAR signaling and T cell activation, and is therefore likely to be resistant to the T cell-suppressive microenvironment typical of many tumors.

Thus, a "bi-functional CAR," encompasses a CAR capable of killing target cells by effector cell mediated mechanisms and target ligand mediated mechanisms when expressed in an immune effector cell.

In accordance with the present invention, a CAR as described herein comprises a target-specific binding domain, a hinge or spacer region, a transmembrane domain, an intracellular signaling domain, such as a signaling domain derived from CD3ζ or FcRy, and optionally, one or more co-stimulatory signaling domains derived from a co-stimulatory molecule such as CD28, CD137, CD134 or CD278.

As used herein, the terms, "binding domain," or, "extracellular domain," are used interchangeably and provide the CAR with the ability to bind to the target antigen of interest. A binding domain can be any protein, polypeptide, oligopeptide, or peptide that possesses the ability to specifically recognize and bind to a biological molecule {e.g., a cell surface receptor or tumor protein, or a component thereof). A binding domain includes any naturally occurring, synthetic, semi-synthetic, or recombinantly produced binding partner for a biological molecule of interest. For example, and as further described herein, a binding domain may be antibody light chain and heavy chain variable regions, or the light and heavy chain variable regions can be joined together in a single chain and in either orientation {e.g., VL-VH or VH-VL). A variety of assays are known for identifying binding domains of the present disclosure that specifically bind with a particular target, including Western blot, ELISA, flow cytometry, or surface plasmon resonance analysis {e.g., using BIACORE™ analysis). The target may be any antigen of clinical interest against which it would be desirable to trigger an effector immune response that results in tumor killing. In one embodiment, the target antigen of the binding domain of the chimeric antigen receptor is CD3 . Illustrative binding domains include immunoglobulin antigen-binding domains such as scFv, scTCR, extracellular domains of receptors, ligands for cell surface molecules/receptors, or receptor binding domains thereof, and tumor binding proteins. In certain embodiments, the antigen binding domains can be a variable region (Fv), a CDR, a Fab, an scFv, a VH, a VL, a domain antibody variant (dAb), a camelid antibody (VHH), a fibronectin 3 domain variant, an ankyrin repeat variant and other antigen-specific binding domain derived from other protein scaffolds.

In one embodiment, the binding domain is a single chain antibody (scFv) and may be a murine, human or humanized scFv. Single chain antibodies may be cloned form the V region genes of a hybridoma specific for a desired target. The production of such hybridomas has become routine. A technique which can be used for cloning the variable region heavy chain (VH) and variable region light chain (VL) has been described, for example, in Orlandi et al., PNAS, 1989; 86: 3833-3837. Thus, in certain embodiments, a binding domain comprises an antibody- derived binding domain but can be a non-antibody derived binding domain. An antibody-derived binding domain can be a fragment of an antibody or a genetically engineered product of one or more fragments of the antibody, which fragment is involved in binding with the antigen.

As would be understood by the skilled person and as described elsewhere herein, a complete antibody comprises two heavy chains and two light chains. Each heavy chain consists of a variable region and a first, second, and third constant region, while each light chain consists of a variable region and a constant region. Mammalian heavy chains are classified as α, δ, ε, γ, and μ, and mammalian light chains are classified as λ or κ. Immunoglobins comprising the α, δ, ε, γ, and μ heavy chains are classified as immunoglobin (Ig)A, IgD, IgE, IgG, and IgM. The complete antibody forms a "Y" shape. The stem of the Y consists of the second and third constant regions (and for IgE and IgM, the fourth constant region) of two heavy chains bound together and disulfide bonds (inter-chain) are formed in the hinge. Heavy chains γ, a and δ have a constant region composed of three tandem (in a line) Ig domains, and a hinge region for added flexibility; heavy chains μ and ε have a constant region composed of four immunoglobulin domains. The second and third constant regions are referred to as "CH2 domain" and "CH3 domain", respectively. Each arm of the Y includes the variable region and first constant region of a single heavy chain bound to the variable and constant regions of a single light chain. The variable regions of the light and heavy chains are responsible for antigen binding.

"Complementarity determining region" or "CDR" with regard to an antibody or antigen- binding fragment thereof refers to a highly variable loop in the variable region of the heavy chain or the light chain of an antibody. CDRs can interact with the antigen conformation and largely determine binding to the antigen (although some framework regions are known to be involved in binding). The heavy chain variable region and the light chain variable region each contain 3 CDRs. The CDRs can be defined or identified by conventional methods, such as by sequence according to Kabat et al (Wu, TT and Kabat, E. A., J Exp Med. 132(2):211-50, (1970); Borden, P. and Kabat E. A., PNAS, 84: 2440-2443 (1987); Kabat, E. A. et al, Sequences of proteins of immunological interest, Published by DIANE Publishing, 1992), or by structure according to Chothia et al (Choithia, C. and Lesk, A.M., J Mol. Biol., 196(4): 901-917 (1987), Choithia, C. et al, Nature, 342: 877 - 883 (1989)).

"Heavy chain variable region" or "VH" refers to the fragment of the heavy chain of an antibody that contains three CDRs interposed between flanking stretches known as framework regions, which are more highly conserved than the CDRs and form a scaffold to support the CDRs.

"Light chain variable region" or "VL" refers to the fragment of the light chain of an antibody that contains three CDRs interposed between framework regions.

"Fv" refers to the smallest fragment of an antibody to bear the complete antigen binding site. An Fv fragment consists of the variable region of a single light chain bound to the variable region of a single heavy chain.

"Single-chain Fv antibody" or "scFv" refers to an engineered antibody consisting of a light chain variable region and a heavy chain variable region connected to one another directly or via a peptide linker sequence.

"Single domain camel antibody" or "camelid VHH" as used herein refers to the smallest known antigen-binding unit of a heavy chain antibody (Koch-Nolte, et al, FASEB J., 21 : 3490- 3498 (2007)). A "heavy chain antibody" or a "camelid antibody" refers to an antibody that contains two VH domains and no light chains (Riechmann L. et al, J. Immunol. Methods 231 :25— 38 (1999); WO94/04678; W094/25591; U.S. Patent No. 6,005,079).

"Single domain antibody" or "dAb" refers to an antibody fragment that consists of the variable region of an antibody heavy chain (VH domain) or the variable region of an antibody light chain (VL domain) (Holt, L., et al, Trends in Biotechnology, 21(11): 484-490).

A "variable region linking sequence" is an amino acid sequence that connects a heavy chain variable region to a light chain variable region and provides a spacer function compatible with interaction of the two sub-binding domains so that the resulting polypeptide retains a specific binding affinity to the same target molecule as an antibody that comprises the same light and heavy chain variable regions.

An exemplary humanized CD37-specific binding domain is an immunoglobulin variable region specific for CD37 that comprises at least one human framework region. A "human framework region" refers to a wild type (i.e., naturally occurring) framework region of a human immunoglobulin variable region, an altered framework region of a human immunoglobulin variable region with less than about 50% (e.g., preferably less than about 45%, 40%, 30%, 25%, 20%, 15%, 10%, 5%, or 1%) of the amino acids in the region are deleted or substituted (e.g., with one or more amino acid residues of a nonhuman immunoglobulin framework region at corresponding positions), or an altered framework region of a nonhuman immunoglobulin variable region with less than about 50% (e.g., less than 45%, 40%, 30%, 25%, 20%, 15%, 10%, or 5%) of the amino acids in the region deleted or substituted (e.g., at positions of exposed residues and/or with one or more amino acid residues of a human immunoglobulin framework region at corresponding positions) so that, in one aspect, immunogenicity is reduced.

In certain embodiments, a human framework region is a wild type framework region of a human immunoglobulin variable region. In certain other embodiments, a human framework region is an altered framework region of a human immunoglobulin variable region with amino acid deletions or substitutions at one, two, three, four or five positions. In yet certain other embodiments, a human framework region is an altered framework region of a non-human immunoglobulin variable region with amino acid deletions or substitutions at one, two, three, four or five positions.

In certain embodiments, a humanized CD37-specific binding domain comprises at least one, two, three, four, five, six, seven or eight human framework regions (FR) selected from human light chain FRl, human heavy chain FRl, human light chain FR2, human heavy chain FR2, human light chain FR3, human heavy chain FR3, human light chain FR4, and human heavy chain FR4.

Human FRs that may be present in CD37-specific binding domains also include variants of the exemplary FRs provided herein in which one or two amino acids of the exemplary FRs have been substituted or deleted.

In certain embodiments, a humanized CD37-specific binding domain comprises (a) a humanized light chain variable region that comprises a human light chain FRl, a human light chain FR2, a human light chain FR3, and a human light chain FR4, and (b) a humanized heavy chain variable region that comprises a human heavy chain FRl, a human heavy chain FR2, a human heavy chain FR3, and a human heavy chain FR4.

CD37-specific binding domains provided herein also comprise one, two, three, four, five, or six CDRs. Such CDRs may be nonhuman CDRs or altered nonhuman CDRs selected from CDR1, CDR2 and CDR3 of the light chain and CDR1, CDR2 and CDR3 of the heavy chain. In certain embodiments, a CD37-specific binding domain comprises (a) a light chain variable region that comprises a light chain CDR1, a light chain CDR2, and a light chain CDR3, and (b) a heavy chain variable region that comprises a heavy chain CDR1 , a heavy chain CDR2, and a heavy chain CDR3. Illustrative CD37-specific binding domains are described herein and include the binding domain encoded by nucleotides 4038-4754 of the CD37t, CD37-Z, CD37-BZ, CD37-28Z and CD37-28BZ constructs provided in SEQ ID NOs:l-5. A binding domain (or a CAR comprising a binding domain or a fusion protein containing a binding domain) "specifically binds" to a target molecule if it binds to or associates with a target molecule with an affinity or Ka (i.e., an equilibrium association constant of a particular binding interaction with units of 1/M) of, for example, greater than or equal to about 10⁵ M^"1. In certain embodiments, a binding domain (or a fusion protein thereof) binds to a target with a Ka greater than or equal to about 10⁶ M^"1, 10⁷ M^"1, 10⁸ M^"1, 10⁹ M^"1, 10¹⁰ M^"1, 10¹¹ M^"1, 10¹² M^"1, or 10¹³ M^"1. "High affinity" binding domains (or single chain fusion proteins thereof) refers to those binding domains with a K_a of at least 10⁷ M^"1, at least 10⁸ M^"1, at least 10⁹ M^"1, at least 10¹⁰ M^"1, at least 10¹¹ M^"1, at least 10¹² M^"1, at least 10¹³ M^"1, or greater. Alternatively, affinity may be defined as an equilibrium dissociation constant (K_d) of a particular binding interaction with units of M (e.g., 10^~5 M to 10^~13 M, or less). Affinities of binding domain polypeptides and CAR proteins according to the present disclosure can be readily determined using conventional techniques (see, e.g., Scatchard et al. (1949) Ann. N.Y. Acad. Sci. 51 :660; and U.S. Patent Nos. 5,283,173; 5,468,614, or the equivalent).

In certain embodiments, the chimeric antigen receptors of the present invention may comprise linker residues between the various domains, added for appropriate spacing and conformation of the molecule. For example, in one embodiment, there may be a linker between the binding domain VH or VL which may be between 1-10 amino acids long. In other embodiments, the linker between any of the domains of the chimeric antigen receptor may be between 1-20 or 20 amino acids long. In this regard, the linker may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 amino acids long. In further embodiments, the linker may be 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 amino acids long.

In certain embodiments, linkers suitable for use in the CAR described herein are flexible linkers. Suitable linkers can be readily selected and can be of any of a suitable of different lengths, such as from 1 amino acid (e.g., Gly) to 20 amino acids, from 2 amino acids to 15 amino acids, from 3 amino acids to 12 amino acids, including 4 amino acids to 10 amino acids, 5 amino acids to 9 amino acids, 6 amino acids to 8 amino acids, or 7 amino acids to 8 amino acids, and may be 1, 2, 3, 4, 5, 6, or 7 amino acids.

Exemplary flexible linkers include glycine polymers (G)_n, glycine-serine polymers, where n is an integer of at least one, glycine-alanine polymers, alanine-serine polymers, and other flexible linkers known in the art. Glycine and glycine-serine polymers are relatively unstructured, and therefore may be able to serve as a neutral tether between domains of fusion proteins such as the CARs described herein. Glycine accesses significantly more phi-psi space than even alanine, and is much less restricted than residues with longer side chains (see Scheraga, Rev. Computational Chem. 11173-142 (1992)). The ordinarily skilled artisan will recognize that design of a CAR can include linkers that are all or partially flexible, such that the linker can include a flexible linker as well as one or more portions that confer less flexible structure to provide for a desired CAR structure.

The binding domain of the CAR is generally followed by a "spacer," or, "hinge," which refers to the region that moves the antigen binding domain away from the effector cell surface to enable proper cell/cell contact, antigen binding and activation (Patel et al., Gene Therapy, 1999; 6: 412-419). The hinge region in a CAR is generally between the TM and the binding domain. In certain embodiments, a hinge region is an immunoglobulin hinge region and may be a wild type immunoglobulin hinge region or an altered wild type immunoglobulin hinge region. Other exemplary hinge regions used in the CARs described herein include the hinge region derived from the extracellular regions of type 1 membrane proteins such as CD8a, CD4, CD28 and CD7, which may be wild-type hinge regions from these molecules or may be altered.

An "altered wild type hinge region" or "altered hinge region" refers to (a) a wild type hinge region with up to 30% amino acid changes (e.g., up to 25%>, 20%o, 15%, 10%o, or 5%> amino acid substitutions or deletions), (b) a portion of a wild type hinge region that is at least 10 amino acids (e.g., at least 12, 13, 14 or 15 amino acids) in length with up to 30%o amino acid changes (e.g., up to 25%o, 20%o, 15%, 10%o, or 5%> amino acid substitutions or deletions), or (c) a portion of a wild type hinge region that comprises the core hinge region (which may be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, or at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 amino acids in length). When an altered wild type hinge region is interposed between and connecting a CD37-specific binding domain and another region (e.g., a transmembrane domain) in the chimeric antigen receptors described herein, it allows the chimeric fusion protein to maintain specific binding to CD37. In certain embodiments, one or more cysteine residues in a wild type immunoglobulin hinge region may be substituted by one or more other amino acid residues (e.g., one or more serine residues). An altered immunoglobulin hinge region may alternatively or additionally have a proline residue of a wild type immunoglobulin hinge region substituted by another amino acid residue (e.g., a serine residue).

The "transmembrane," region or domain is the portion of the CAR that anchors the extracellular binding portion to the plasma membrane of the immune effector cell, and facilitates binding of the binding domain to the target antigen. The transmembrane domain may be a CD3ζ transmembrane domain, however other transmembrane domains that may be employed include those obtained from CD8a, CD4, CD28, CD45, CD9, CD16, CD22, CD33, CD64, CD80, CD86, CD134, CD137, and CD154. In one embodiment, the transmembrane domain is the transmembrane domain of CD8, such as provided in the anti-CD37 CARs provided in SEQ ID NOs: l-5 (see also Tables 1-5 for specific nucleotide positions encoding the CD8a hinge and TM). In certain embodiments, the transmembrane domain is synthetic in which case it would comprise predominantly hydrophobic residues such as leucine and valine.

The "intracellular signaling domain," refers to the part of the chimeric antigen receptor protein that participates in transducing the message of effective CAR binding to a target antigen into the interior of the immune effector cell to elicit effector cell function, e.g., activation, cytokine production, proliferation and cytotoxic activity, including the release of cytotoxic factors to the CAR-bound target cell, or other cellular responses elicited with antigen binding to the extracellular CAR domain. The term "effector function" refers to a specialized function of the cell. Effector function of the T cell, for example, may be cytolytic activity or help or activity including the secretion of a cytokine. Thus, the term "intracellular signaling domain" refers to the portion of a protein which transduces the effector function signal and that directs the cell to perform a specialized function. While usually the entire intracellular signaling domain can be employed, in many cases it is not necessary to use the entire domain. To the extent that a truncated portion of an intracellular signaling domain is used, such truncated portion may be used in place of the entire domain as long as it transduces the effector function signal. The term intracellular signaling domain is meant to include any truncated portion of the intracellular signaling domain sufficient to transducing effector function signal. The intracellular signaling domain is also known as the, "signal transduction domain," and is typically derived from portions of the human CD3ζ or FcRy chains.

It is known that signals generated through the T cell receptor alone are insufficient for full activation of the T cell and that a secondary, or costimulatory signal is also required. Thus, T cell activation can be said to be mediated by two distinct classes of cytoplasmic signaling sequences: those that initiate antigen dependent primary activation through the T cell receptor (primary cytoplasmic signaling sequences) and those that act in an antigen independent manner to provide a secondary or costimulatory signal (secondary cytoplasmic signaling sequences). Primary cytoplasmic signaling sequences regulate primary activation of the T cell receptor complex either an inhibitory way, or in an inhibitory way. Primary cytoplasmic signaling sequences that act in a costimulatory manner may contain signaling motifs which are known as immunoreceptor tyrosine - based activation motif or ITAMs.

Examples of IT AM containing primary cytoplasmic signaling sequences that are of particular used in the invention include those derived from TCRζ, FcRy, FcR , CD3y, CD38, CD38, CD5, CD22, CD79a, CD79b and CD66d. In certain particular embodiments, the intracellular signaling domain of the anti-CD37 CARs described herein are derived from CD3ζ or FcRy. As used herein, the term, "co-stimulatory signaling domain," or "co-stimulatory domain", refers to the portion of the CAR comprising the intracellular domain of a co-stimulatory molecule. Co-stimulatory molecules are cell surface molecules other than antigen receptors or Fc receptors that provide a second signal required for efficient activation and function of T lymphocytes upon binding to antigen. Examples of such co-stimulatory molecules include CD27, CD28, 4- IBB (CD137), OX40 (CD134), CD30, CD40, PD-1 , ICOS (CD278), LFA-1 , CD2, CD7, LIGHT, NKD2C, B7-H2 and a ligand that specifically binds CD83. Accordingly, while the present disclosure provides exemplary costimulatory domains derived from CD28 and 4-1BB, other costimulatory domains are contemplated for use with the CARs described herein. The inclusion of one or more co-stimulatory signaling domains may enhance the efficacy and expansion of T cells expressing CAR receptors. The intracellular signaling and co-stimulatory signaling domains may be linked in any order in tandem to the carboxyl terminus of the transmembrane domain.

As used herein, the term, "chimeric," describes being composed of parts of different proteins or DNAs from different origins. For example, the chimeric CD37 CAR proteins may comprise polypeptide portions of different proteins such as: (a) an anti-CD37 scFv as a binding domain (b) a hinge region derived from human CD8a, (c) a human CD8a transmembrane domain, and (d) a human T cell receptor CD3 zeta chain (CD3Q) intracellular signaling domain, and optionally one or more co-stimulatory signaling domains derived from CD28, CD137, CD134, and CD278. In one embodiment, the different protein domains are arranged from amino to carboxyl terminus in the following order: binding domain, hinge region and transmembrane domain. The intracellular signaling domain and optional co-stimulatory signaling domains are linked to the transmembrane carboxy terminus in any order in tandem to form a single chain chimeric polypeptide. The nucleic acid construct encoding a CD37 CAR is a chimeric nucleic acid comprising a nucleic acid sequence of different coding sequences, for example: the coding sequences of a humanized anti-CD37 scFv, a human CD8a-hinge, a human CD28 transmembrane domain and a CD3ζ intracellular signaling domain.

The present disclosure provides CAR polypeptides, and fragments thereof. The terms "polypeptide" "protein" and "peptide" and "glycoprotein" are used interchangeably and mean a polymer of amino acids not limited to any particular length. The term does not exclude modifications such as myristylation, sulfation, glycosylation, phosphorylation and addition or deletion of signal sequences. The terms "polypeptide" or "protein" means one or more chains of amino acids, wherein each chain comprises amino acids covalently linked by peptide bonds, and wherein said polypeptide or protein can comprise a plurality of chains non-covalently and/or covalently linked together by peptide bonds, having the sequence of native proteins, that is, proteins produced by naturally-occurring and specifically non-recombinant cells, or genetically-engineered or recombinant cells, and comprise molecules having the amino acid sequence of the native protein, or molecules having deletions from, additions to, and/or substitutions of one or more amino acids of the native sequence. The terms "polypeptide" and "protein" specifically encompass the CARs of the present disclosure, or sequences that have deletions from, additions to, and/or substitutions of one or more amino acid of a CAR as disclosed herein.

The term "isolated protein" referred to herein means that a subject protein (1) is free of at least some other proteins with which it would typically be found in nature, (2) is essentially free of other proteins from the same source, e.g., from the same species, (3) is expressed by a cell from a different species, (4) has been separated from at least about 50 percent of polynucleotides, lipids, carbohydrates, or other materials with which it is associated in nature, (5) is not associated (by covalent or noncovalent interaction) with portions of a protein with which the "isolated protein" is associated in nature, (6) is operably associated (by covalent or noncovalent interaction) with a polypeptide with which it is not associated in nature, or (7) does not occur in nature. Such an isolated protein can be encoded by genomic DNA, cDNA, mRNA or other RNA, of may be of synthetic origin, or any combination thereof. In certain embodiments, the isolated protein is substantially free from proteins or polypeptides or other contaminants that are found in its natural environment that would interfere with its use (therapeutic, diagnostic, prophylactic, research or otherwise).

The term "polypeptide fragment" refers to a polypeptide, which can be monomeric or multimeric, that has an amino-terminal deletion, a carboxyl-terminal deletion, and/or an internal deletion or substitution of a naturally-occurring or recombinantly -produced polypeptide. In certain embodiments, a polypeptide fragment can comprise an amino acid chain at least 5 to about 500 amino acids long. It will be appreciated that in certain embodiments, fragments are at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 150, 200, 250, 300, 350, 400, or 450 amino acids long. Particularly useful polypeptide fragments include functional domains, including antigen-binding domains or fragments of antibodies. In the case of an anti-CD37, or other antibody, useful fragments include, but are not limited to: a CDR region, especially a CDR3 region of the heavy or light chain; a variable region of a heavy or light chain; a portion of an antibody chain or just its variable region including two CDRs; and the like.

Polypeptides may comprise a signal (or leader) sequence at the N-terminal end of the protein, which co-translationally or post-translationally directs transfer of the protein. The polypeptide may also be fused in-frame or conjugated to a linker or other sequence for ease of synthesis, purification or identification of the polypeptide (e.g., poly -His), or to enhance binding of the polypeptide to a solid support.

Amino acid sequence modification(s) of the CARs described herein are contemplated. For example, it may be desirable to improve the binding affinity and/or other biological properties of the CAR. For example, amino acid sequence variants of a CAR, or binding domain, or a stimulatory signaling domain thereof, may be prepared by introducing appropriate nucleotide changes into a polynucleotide that encodes the CAR, or a domain thereof, or by peptide synthesis. Such modifications include, for example, deletions from, and/or insertions into and/or substitutions of, residues within the amino acid sequences of the CAR. Any combination of deletion, insertion, and substitution may be made to arrive at the final CAR, provided that the final construct possesses the desired characteristics, such as specific binding to a target antigen of interest by a binding domain, or increased signaling by the intracellular signaling domain. The amino acid changes also may alter post-translational processes of the CAR, such as changing the number or position of glycosylation sites. Any of the variations and modifications described above for polypeptides of the present invention may be included in the CARs of the present invention.

The present disclosure provides variants of the CAR disclosed herein. In certain embodiments, such variant CAR comprise variant binding domains, or antigen-binding fragments, or CDRs thereof, bind to a target of interest at least about 50%, at least about 70%, and in certain embodiments, at least about 90% as well as a given reference or wild-type sequence, including any such sequences specifically set forth herein. In further embodiments, such variants bind to a target antigen with greater affinity the reference or wild-type sequence set forth herein, for example, that bind quantitatively at least about 105%, 106%, 107%, 108%, 109%, or 110% as well as a reference sequence specifically set forth herein.

In particular embodiments, a subject CAR may have: an amino acid sequence that is at least 80% identical, at least 85%, at least 90%, at least 95% identical, or at least 98% or 99% identical, to the CAR described herein.

Determination of the three-dimensional structures of representative polypeptides may be made through routine methodologies such that substitution, addition, deletion or insertion of one or more amino acids with selected natural or non-natural amino acids can be virtually modeled for purposes of determining whether a so derived structural variant retains the space-filling properties of presently disclosed species. See, for instance, Donate et al., 1994 Prot. Sci. 3:2378; Bradley et al, Science 309: 1868-1871 (2005); Schueler-Furman et al, Science 310:638 (2005); Dietz et al, Proc. Nat. Acad. Sci. USA 103 :1244 (2006); Dodson et al., Nature 450:176 (2007); Qian et al., Nature 450:259 (2007); Raman et al. Science 327:1014-1018 (2010). Some additional non-limiting examples of computer algorithms that may be used for these and related embodiments, include VMD which is a molecular visualization program for displaying, animating, and analyzing large biomolecular systems using 3-D graphics and built-in scripting (see the website for the Theoretical and Computational Biophysics Group, University of Illinois at Urbana-Champagne, at ks.uiuc.edu/Research/vmd/. Many other computer programs are known in the art and available to the skilled person and which allow for determining atomic dimensions from space-filling models (van der Waals radii) of energy-minimized conformations; GRID, which seeks to determine regions of high affinity for different chemical groups, thereby enhancing binding, Monte Carlo searches, which calculate mathematical alignment, and CHARMM (Brooks et al. (1983) J. Comput. Chem. 4:187-217) and AMBER (Weiner et al (1981) J. Comput. Chem. 106: 765), which assess force field calculations, and analysis (see also, Eisenfield et al. (1991) Am. J. Physiol. 261 :C376-386; Lybrand (1991) J. Pharm. Belg. 46:49-54; Froimowitz (1990) Biotechniques 8:640-644; Burbam et al.

(1990) Proteins 7:99-111 ; Pedersen (1985) Environ. Health Perspect. 61 :185-190; and Kini et al.

(1991) J. Biomol. Struct. Dyn. 9:475-488). A variety of appropriate computational computer programs are also commercially available, such as from Schrodinger (Munich, Germany).

The present disclosure further provides in certain embodiments an isolated nucleic acid encoding the polypeptide CAR as described herein. Illustrative polynucleotides are provided in SEQ ID NOs: 1-6. The term, "coding sequence," as used herein is the nucleic sequence which is transcribed (DNA) and translated (mRNA) into a polypeptide in vitro or in vivo when operably linked to appropriate regulatory sequences. The term "isolated polynucleotide" or "isolated nucleic acid" as used herein shall mean a polynucleotide of genomic, cDNA, or synthetic origin or some combination thereof, which by virtue of its origin the isolated polynucleotide (1) is not associated with all or a portion of a polynucleotide in which the isolated polynucleotide is found in nature, (2) is linked to a polynucleotide to which it is not linked in nature, or (3) does not occur in nature as part of a larger sequence. The nucleic acids described herein include DNA and RNA and may also include chemical derivatives of DNA or RNA, including molecules having a radioactive isotope or a chemical adduct such as a fluorophore, chromophore or biotin ("label").

The term "polynucleotide" as referred to herein means single-stranded or double-stranded nucleic acid polymers. In certain embodiments, the nucleotides comprising the polynucleotide can be ribonucleotides or deoxyribonucleotides or a modified form of either type of nucleotide. Said modifications include base modifications such as bromouridine, ribose modifications such as arabinoside and 2',3'-dideoxyribose and internucleotide linkage modifications such as phosphorothioate, phosphorodithioate, phosphoroselenoate, phosphorodiselenoate, phosphoroanilothioate, phoshoraniladate and phosphoroamidate. The term "polynucleotide" specifically includes single and double stranded forms of DNA and RNA. The term "naturally occurring nucleotides" includes deoxyribonucleotides and ribonucleotides. The term "modified nucleotides" includes nucleotides with modified or substituted sugar groups and the like. The term "oligonucleotide linkages" includes oligonucleotide linkages such as phosphorothioate, phosphorodithioate, phosphoroselenoate, phosphorodiselenoate, phosphoroanilothioate, phoshoraniladate, phosphoroamidate, and the like. See, e.g., LaPlanche et al, 1986, Nucl. Acids Res., 14:9081 ; Stec et al, 1984, J. Am. Chem. Soc, 106:6077; Stein et al, 1988, Nucl. Acids Res., 16:3209; Zon et al, 1991, Anti-Cancer Drug Design, 6:539; Zon et al, 1991, OLIGONUCLEOTIDES AND ANALOGUES: A PRACTICAL APPROACH, pp. 87-108 (F. Eckstein, Ed.), Oxford University Press, Oxford England; Stec et al, U.S. Pat. No. 5,151,510; Uhlmann and Peyman, 1990, Chemical Reviews, 90:543, the disclosures of which are hereby incorporated by reference for any purpose. An oligonucleotide can include a detectable label to enable detection of the oligonucleotide or hybridization thereof.

In other related embodiments, polynucleotide variants may have substantial identity to a polynucleotide sequence encoding a CAR, or domain thereof as described herein. For example, a polynucleotide may be a polynucleotide comprising at least 70% sequence identity, preferably at least 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% or higher, sequence identity compared to a reference polynucleotide sequence such as a sequence encoding a CAR or domain thereof described herein, using the methods described herein, (e.g., BLAST analysis using standard parameters, as described below). One skilled in this art will recognize that these values can be appropriately adjusted to determine corresponding identity of proteins encoded by two nucleotide sequences by taking into account codon degeneracy, amino acid similarity, reading frame positioning and the like.

Typically, polynucleotide variants will contain one or more substitutions, additions, deletions and/or insertions, preferably such that the binding affinity of a binding domain, or function of the CAR encoded by the variant polynucleotide is not substantially diminished relative to the unmodified reference protein encoded by a polynucleotide sequence specifically set forth herein.

In certain other related embodiments, polynucleotide fragments may comprise or consist essentially of various lengths of contiguous stretches of sequence identical to or complementary to a sequence encoding a CAR or domain thereof as described herein. For example, polynucleotides are provided that comprise or consist essentially of at least about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 200, 300, 400, 500 or 1000 or more contiguous nucleotides of a sequences the encodes a CAR or domain thereof, such as a binding domain or intracellular signaling domain, or costimulatory signaling domain thereof, disclosed herein as well as all intermediate lengths there between. It will be readily understood that "intermediate lengths", in this context, means any length between the quoted values, such as 50, 51, 52, 53, etc.; 100, 101, 102, 103, etc.; 150, 151, 152, 153, etc.; including all integers through 200- 500; 500-1,000, and the like. A polynucleotide sequence as described here may be extended at one or both ends by additional nucleotides not found in the native sequence. This additional sequence may consist of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 nucleotides at either end of a polynucleotide encoding a CAR or domain thereof described herein or at both ends of a polynucleotide encoding a CAR or domain thereof described herein.

In another embodiment, polynucleotides are provided that are capable of hybridizing under moderate to high stringency conditions to a polynucleotide sequence encoding a CAR or domain thereof, such as a binding domain or intracellular signaling domain or costimulatory signaling domain thereof, or a complementary sequence thereof. Hybridization techniques are well known in the art of molecular biology. For purposes of illustration, suitable moderately stringent conditions for testing the hybridization of a polynucleotide as provided herein with other polynucleotides include prewashing in a solution of 5 X SSC, 0.5% SDS, 1.0 mM EDTA (pH 8.0); hybridizing at 50°C-60°C, 5 X SSC, overnight; followed by washing twice at 65°C for 20 minutes with each of 2X, 0.5X and 0.2X SSC containing 0.1% SDS. One skilled in the art will understand that the stringency of hybridization can be readily manipulated, such as by altering the salt content of the hybridization solution and/or the temperature at which the hybridization is performed. For example, in another embodiment, suitable highly stringent hybridization conditions include those described above, with the exception that the temperature of hybridization is increased, e.g., to 60°C- 65°C or 65°C-70°C.

In certain embodiments, the polynucleotides described above, e.g., polynucleotide variants, fragments and hybridizing sequences, encode a CAR or domain thereof, such as a binding domain, intracellular signaling domain, transmembrane domain, or a costimulatory signaling domain. In other embodiments, such polynucleotides encode CAR that bind to CD37 or other tumor antigen at least about 50%, at least about 70%, and in certain embodiments, at least about 90% as well as a CAR sequence specifically set forth herein. In further embodiments, such polynucleotides encode a CAR or domain thereof, that, e.g., bind to CD37 with greater affinity than the CAR, or domain thereof, set forth herein, for example, that bind quantitatively at least about 105%, 106%, 107%, 108%o, 109%o, or 110%> as well as a CAR, or domain thereof, sequence specifically set forth herein.

Determination of the three-dimensional structures of representative polypeptides {e.g., variant CAR as provided herein) may be made through routine methodologies such that substitution, addition, deletion or insertion of one or more amino acids with selected natural or non- natural amino acids can be virtually modeled for purposes of determining whether a so derived structural variant retains the space-filling properties of presently disclosed species. A variety of computer programs are known to the skilled artisan for determining appropriate amino acid substitutions (or appropriate polynucleotides encoding the amino acid sequence) within, for example, an antibody or antigen-binding fragment thereof, such that, for example, affinity is maintained or better affinity is achieved.

The polynucleotides described herein, or fragments thereof, regardless of the length of the coding sequence itself, may be combined with other DNA sequences, such as promoters, polyadenylation signals, additional restriction enzyme sites, multiple cloning sites, other coding segments, and the like, such that their overall length may vary considerably. It is therefore contemplated that a nucleic acid fragment of almost any length may be employed, with the total length preferably being limited by the ease of preparation and use in the intended recombinant DNA protocol. For example, illustrative polynucleotide segments with total lengths of about 10,000, about 5000, about 3000, about 2,000, about 1,000, about 500, about 200, about 100, about 50 base pairs in length, and the like, (including all intermediate lengths) are contemplated to be useful.

When comparing polynucleotide sequences, two sequences are said to be "identical" if the sequence of nucleotides in the two sequences is the same when aligned for maximum correspondence, as described below. Comparisons between two sequences are typically performed by comparing the sequences over a comparison window to identify and compare local regions of sequence similarity. A "comparison window" as used herein, refers to a segment of at least about 20 contiguous positions, usually 30 to about 75, 40 to about 50, in which a sequence may be compared to a reference sequence of the same number of contiguous positions after the two sequences are optimally aligned.

Optimal alignment of sequences for comparison may be conducted using the Megalign program in the Lasergene suite of bioinformatics software (DNASTAR, Inc., Madison, WI), using default parameters. This program embodies several alignment schemes described in the following references: Dayhoff, M.O. (1978) A model of evolutionary change in proteins - Matrices for detecting distant relationships. In Dayhoff, M.O. (ed.) Atlas of Protein Sequence and Structure, National Biomedical Research Foundation, Washington DC Vol. 5, Suppl. 3, pp. 345-358; Hein J., Unified Approach to Alignment and Phylogenes, pp. 626-645 (1990); Methods in Enzymology vol. 183, Academic Press, Inc., San Diego, CA; Higgins, D.G. and Sharp, P.M., CABIOS 5:151-153 (1989); Myers, E.W. and Muller W., CABIOS 4:11-17 (1988); Robinson, E.D., Comb. Theor 11:105 (1971); Saitou, N. Nes, M., Mol. Biol. Evol. 4:406-425 (1987); Sneath, P.H.A. and Sokal, R.R., Numerical Taxonomy - the Principles and Practice of Numerical Taxonomy, Freeman Press, San Francisco, CA (1973); Wilbur, W.J. and Lipman, D.J., Proc. Natl. Acad., Sci. USA 50:726-730 (1983).

Alternatively, optimal alignment of sequences for comparison may be conducted by the local identity algorithm of Smith and Waterman, Add. APL. Math 2:482 (1981), by the identity alignment algorithm of Needleman and Wunsch, J. Mol. Biol. 48:443 (1970), by the search for similarity methods of Pearson and Lipman, Proc. Natl. Acad. Sci. USA 85: 2444 (1988), by computerized implementations of these algorithms (GAP, BESTFIT, BLAST, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group (GCG), 575 Science Dr., Madison, WI), or by inspection.

One preferred example of algorithms that are suitable for determining percent sequence identity and sequence similarity are the BLAST and BLAST 2.0 algorithms, which are described in Altschul et al., Nucl. Acids Res. 25:3389-3402 (1977), and Altschul et al, J. Mol. Biol. 215:403- 410 (1990), respectively. BLAST and BLAST 2.0 can be used, for example with the parameters described herein, to determine percent sequence identity among two or more the polynucleotides. Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information. In one illustrative example, cumulative scores can be calculated using, for nucleotide sequences, the parameters M (reward score for a pair of matching residues; always >0) and N (penally score for mismatching residues; always <0). Extension of the word hits in each direction are halted when: the cumulative alignment score falls off by the quantity X from its maximum achieved value; the cumulative score goes to zero or below, due to the accumulation of one or more negative-scoring residue alignments; or the end of either sequence is reached. The BLAST algorithm parameters W, T and X determine the sensitivity and speed of the alignment. The BLASTN program (for nucleotide sequences) uses as defaults a wordlength (W) of 11, and expectation (E) of 10, and the BLOSUM62 scoring matrix (see Henikoff and Henikoff, Proc. Natl. Acad. Sci. USA 89: 10915 (1989)) alignments, (B) of 50, expectation (E) of 10, M=5, N=-4 and a comparison of both strands.

In certain embodiments, the "percentage of sequence identity" is determined by comparing two optimally aligned sequences over a window of comparison of at least 20 positions, wherein the portion of the polynucleotide sequence in the comparison window may comprise additions or deletions (i.e., gaps) of 20 percent or less, usually 5 to 15 percent, or 10 to 12 percent, as compared to the reference sequences (which does not comprise additions or deletions) for optimal alignment of the two sequences. The percentage is calculated by determining the number of positions at which the identical nucleic acid bases occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the reference sequence {i.e., the window size) and multiplying the results by 100 to yield the percentage of sequence identity.

It will be appreciated by those of ordinary skill in the art that, as a result of the degeneracy of the genetic code, there are many nucleotide sequences that encode a CAR as described herein. Some of these polynucleotides bear minimal sequence identity to the nucleotide sequence of the native or original polynucleotide sequence that encode CAR, for example a CAR that binds to CD37 and or a tumor target antigen. Nonetheless, polynucleotides that vary due to differences in codon usage are expressly contemplated by the present disclosure. In certain embodiments, sequences that have been codon-optimized for mammalian expression are specifically contemplated.

Therefore, in another embodiment of the invention, a mutagenesis approach, such as site- specific mutagenesis, may be employed for the preparation of variants and/or derivatives of the CAR described herein. By this approach, specific modifications in a polypeptide sequence can be made through mutagenesis of the underlying polynucleotides that encode them. These techniques provides a straightforward approach to prepare and test sequence variants, for example, incorporating one or more of the foregoing considerations, by introducing one or more nucleotide sequence changes into the polynucleotide.

In certain embodiments, the inventors contemplate the mutagenesis of the polynucleotide sequences that encode a CAR disclosed herein, or a domain thereof, to alter one or more properties of the encoded polypeptide, such as the binding affinity of a binding domain or the function of a particular signaling or costimulatory signaling domain. The techniques of site-specific mutagenesis are well-known in the art, and are widely used to create variants of both polypeptides and polynucleotides. For example, site-specific mutagenesis is often used to alter a specific portion of a DNA molecule. In such embodiments, a primer comprising typically about 14 to about 25 nucleotides or so in length is employed, with about 5 to about 10 residues on both sides of the junction of the sequence being altered.

Conventional polymerase chain reaction (PCR) cloning techniques can be used to construct an isolated nucleic acid encoding the CAR disclosed herein. The isolated nucleic acid can be cloned into a general purpose cloning vector such as pUC19, pBR322, pBluescript vectors (Stratagene Inc.) or pCR TOPO^® from Invitrogen Inc. The resultant nucleic acid construct (recombinant vector) carrying the isolated chimeric nucleic acid encoding a chimeric antigen receptor protein disclosed herein can then be subcloned into expression vectors or viral vectors for protein expression in mammalian cells. The mammalian cells are immune effector cells, preferably human T cells. In certain embodiments, the polynucleotide encoding the CAR described herein is inserted into a vector. The term "vector" as used herein refers to a vehicle into which a polynucleotide encoding a protein may be covalently inserted so as to bring about the expression of that protein and/or the cloning of the polynucleotide. Such vectors may also be referred to as "expression vectors". The isolated polynucleotide may be inserted into a vector using any suitable methods known in the art, for example, without limitation, the vector may be digested using appropriate restriction enzymes and then may be ligated with the isolated polynucleotide having matching restriction ends. Expression vectors have the ability to incorporate and express heterologous or modified nucleic acid sequences coding for at least part of a gene product capable of being transcribed in a cell. In most cases, RNA molecules are then translated into a protein. Expression vectors can contain a variety of control sequences, which refer to nucleic acid sequences necessary for the transcription and possibly translation of an operatively linked coding sequence in a particular host organism. In addition to control sequences that govern transcription and translation, vectors and expression vectors may contain nucleic acid sequences that serve other functions as well and are discussed infra. An expression vector may comprise additional elements, for example, the expression vector may have two replication systems, thus allowing it to be maintained in two organisms, for example in human cells for expression and in a prokaryotic host for cloning and amplification.

The expression vector should have the necessary 5' upstream and 3' downstream regulatory elements such as promoter sequences such as CMV, PGK and EF1 a promoters, ribosome recognition and binding TATA box, and 3 ' UTR AAUAAA transcription termination sequence for the efficient gene transcription and translation in its respective host cell. Other suitable promoters include the constitutive promoter of simian virus 40 (SV40) early promoter, mouse mammary tumor virus (MMTV), HIV LTR promoter, MoMuLV promoter, avian leukemia virus promoter, EBV immediate early promoter, and rous sarcoma virus promoter. Human gene promoters may also be used, including, but not limited to the actin promoter, the myosin promoter, the hemoglobin promoter, and the creatine kinase promoter. In certain embodiments inducible promoters are also contemplated as part of the vectors expressing chimeric antigen receptor. This provides a molecular switch capable of turning on expression of the polynucleotide sequence of interest or turning off expression. Examples of inducible promoters include, but are not limited to a metallothionine promoter, a glucocorticoid promoter, a progesterone promoter, or a tetracycline promoter.

The expression vector can have additional sequence such as 6X- histidine, c-Myc, and FLAG tags which are incorporated into the expressed chimeric proteins disclosed herein. Thus, the expression vector may be engineered to contain 5' and 3' untranslated regulatory sequences that sometimes can function as enhancer sequences, promoter regions and/or terminator sequences that can facilitate or enhance efficient transcription of the nucleic acid(s) of interest carried on the expression vector. An expression vector sometimes also is engineered for replication and/or expression functionality (e.g., transcription and translation) in a particular cell type, cell location, or tissue type. Expression vectors sometimes include a selectable marker for maintenance of the vector in the host or recipient cell.

Examples of vectors are plasmid, autonomously replicating sequences, and transposable elements. Additional exemplary vectors include, without limitation, plasmids, phagemids, cosmids, artificial chromosomes such as yeast artificial chromosome (YAC), bacterial artificial chromosome (BAC), or PI - derived artificial chromosome (PAC), bacteriophages such as lambda phage or Ml 3 phage, and animal viruses. Examples of categories of animal viruses useful as vectors include, without limitation, retrovirus (including lentivirus), adenovirus, adeno-associated virus, herpesvirus (e.g., herpes simplex virus), poxvirus, baculovirus, papillomavirus, and papovavirus (e.g., SV40). Examples of expression vectors are pClneo vectors (Promega) for expression in mammalian cells; pLenti4/V5-DEST™, pLenti6/V5-DEST™, and pLenti6.2/V5-GW/lacZ (Invitrogen) for lentivirus-mediated gene transfer and expression in mammalian cells. The coding sequences of the chimeric proteins disclosed herein can be ligated into such expression vectors for the expression of the chimeric protein in mammalian cells.

In certain embodiments, the nucleic acids encoding the CAR of the present invention are provided in a viral vectors. A viral vector can be those derived from retrovirus, lentivirus, or foamy virus. As used herein, the term, "viral vector," refers to a nucleic acid vector construct that includes at least one element of viral origin and has the capacity to be packaged into a viral vector particle. The viral vector can contain the coding sequence for a scFvCD37-CD3^ and the various chimeric proteins described herein in place of nonessential viral genes. The vector and/or particle can be utilized for the purpose of transferring DNA, RNA or other nucleic acids into cells either in vitro or in vivo. Numerous forms of viral vectors are known in the art.

In certain embodiments, the viral vector containing the coding sequence for a CAR described herein is a retroviral vector or a lentiviral vector. The term "retroviral vector" refers to a vector containing structural and functional genetic elements that are primarily derived from a retrovirus. The term "lentiviral vector" refers to a vector containing structural and functional genetic elements outside the LTRs that are primarily derived from a lentivirus. The term "self- inactivating vector" refers to vectors in which the right (3') LTR enhancer-promoter region, know as the U3 region, has been modified (e.g., by deletion or substitution) to prevent viral transcription beyond the first round of viral replication. Consequently, the vectors are capable of infecting and then integrating into the host genome only once, and can not be passed further. This is because the right (3') LTR U3 region is used as a template for the left (5') LTR U3 region during viral replication and, thus, the viral transcript can not be made without the U3 enhancer-promoter. If the viral transcript is not made, it can not be processed or packaged into virions, hence the life cycle of the virus ends. Accordingly, SIN vectors greatly reduce risk of creating unwanted replication- competent virus since the right (3') LTR U3 region has been modified to prevent viral transcription beyond the first round of replication, hence eliminating the ability of the virus to be passed.

The retroviral vectors for use herein can be derived from any known retrovirus (e.g., type c retroviruses, such as Moloney murine sarcoma virus (MoMSV), Harvey murine sarcoma virus (HaMuSV), murine mammary tumor virus (MuMTV), gibbon ape leukemia virus (GaLV), feline leukemia virus (FLV), spumavirus, Friend, Murine Stem Cell Virus (MSCV) and Rous Sarcoma Virus (RSV)). Retroviruses" of the invention also include human T cell leukemia viruses, HTLV-1 and HTLV-2, and the lentiviral family of retroviruses, such as Human Immunodeficiency Viruses, HrV-1, HIV-2, simian immunodeficiency virus (SIV), feline immunodeficiency virus (FIV), equine immnodeficiency virus (EIV), and other classes of retroviruses.

A lentiviral vector for use herein refers to a vector derived from a lentivirus, a group (or genus) of retroviruses that give rise to slowly developing disease. Viruses included within this group include HIV (human immunodeficiency virus; including HIV type 1, and HIV type 2), the etiologic agent of the human acquired immunodeficiency syndrome (AIDS); visna-maedi, which causes encephalitis (visna) or pneumonia (maedi) in sheep, the caprine arthritis-encephalitis virus, which causes immune deficiency, arthritis, and encephalopathy in goats; equine infectious anemia virus, which causes autoimmune hemolytic anemia, and encephalopathy in horses; feline immunodeficiency virus (FIV), which causes immune deficiency in cats; bovine immune deficiency virus (BIV), which causes lymphadenopathy, lymphocytosis, and possibly central nervous system infection in cattle; and simian immunodeficiency virus (SIV), which cause immune deficiency and encephalopathy in sub-human primates. Usually, the viruses latently infect monocytes and macrophages, from which they spread to other cells. HIV, FIV, and SIV also readily infect T lymphocytes (i.e., T-cells). An HIV-1 based lentivirus can effectively transduce non-dividing cells whereas MMLV cannot (Naldini et al., Science, 1996; 272: 263-267). Preparation of the recombinant lentivirus can be achieved using the methods according to Dull et al. and Zufferey et al. (Dull et al., J. Virol., 1998; 72: 8463-8471 and Zufferey et al., J. Virol. 1998; 72:9873-9880).

The phrase "retroviral packaging cell line" refers to a cell line (typically a mammalian cell line) which contains the necessary coding sequences to produce viral particles which lack the ability to package RNA and produce replication-competent helper-virus. When the packaging function is provided within the cell line (e.g., in trans by way of a plasmid vector), the packaging cell line produces recombinant retrovirus, thereby becoming a "retroviral producer cell line." Retroviral vectors for use in the present invention can be formed using standard cloning techniques by combining the desired DNA sequences in the order and orientation described herein (Current Protocols in Molecular Biology, Ausubel, F.M. et al. (eds.) Greene Publishing Associates, (1989), Sections 9.10-9.14 and other standard laboratory manuals; Eglitis, et al. (1985) Science 230: 1395-1398; Danos and Mulligan (1988) Proc. Natl. Acad. Sci. USA 85:6460-6464; Wilson et al. (1988) Proc. Natl. Acad. Sci. USA 85:3014-3018; Armentano et al. (1990) Proc. Natl. Acad. Sci. USA 87:6141-6145; Huber et al. (1991) Proc. Natl. Acad. Sci. USA 88:8039-8043; Ferry et al. (1991) Proc. Natl. Acad. Sci. USA 88:8377-8381 ; Chowdhury et al. (1991) Science 254:1802- 1805; van Beusechem et al. (1992) Proc. Natl. Acad. Sci. USA 89:7640-7644; Kay et al. (1992) Human Gene Therapy 3:641-647; Dai et al. (1992) Proc. Natl. Acad. Sci. USA 89: 10892-10895; Hwu et al. (1993) J. Immunol. 150:4104-4115; U.S. Patent No. 4,868,116; U.S. Patent No. 4,980,286; PCT Application WO 89/07136; PCT Application WO 89/02468; PCT Application WO 89/05345; and PCT Application WO 92/07573).

Suitable sources for obtaining retroviral (i.e., both lentiviral and non-lentiviral) sequences for use in forming the vectors include, for example, genomic RNA and cDNAs available from commercially available sources, including the Type Culture Collection (ATCC), Rockville, MD. The sequences also can be synthesized chemically.

Particularly illustrative viral vectors for use with the CARs described herein are described in WO2002087341, WO2002083080, WO2002082908, WO2004000220 and WO2004054512.

The term "operably linked" means that the components to which the term is applied are in a relationship that allows them to carry out their inherent functions under suitable conditions. For example, a transcription control sequence "operably linked" to a protein coding sequence is ligated thereto so that expression of the protein coding sequence is achieved under conditions compatible with the transcriptional activity of the control sequences.

The term "control sequence" as used herein refers to polynucleotide sequences that can affect expression, processing or intracellular localization of coding sequences to which they are ligated or operably linked. The nature of such control sequences may depend upon the host organism. In particular embodiments, transcription control sequences for prokaryotes may include a promoter, ribosomal binding site, and transcription termination sequence. In other particular embodiments, transcription control sequences for eukaryotes may include promoters comprising one or a plurality of recognition sites for transcription factors, transcription enhancer sequences, transcription termination sequences and polyadenylation sequences. In certain embodiments, "control sequences" can include leader sequences and/or fusion partner sequences.

For expression of the polypeptide, the vector may be introduced into a host cell to allow expression of the polypeptide within the host cell. The expression vectors may contain a variety of elements for controlling expression, including without limitation, promoter sequences, transcription initiation sequences, enhancer sequences, selectable markers, and signal sequences. These elements may be selected as appropriate by a person of ordinary skill in the art. For example, the promoter sequences may be selected to promote the transcription of the polynucleotide in the vector. Suitable promoter sequences include, without limitation, T7 promoter, T3 promoter, SP6 promoter, beta-actin promoter, EFla promoter, CMV promoter, and SV40 promoter. Enhancer sequences may be selected to enhance the transcription of the polynucleotide. Selectable markers may be selected to allow selection of the host cells inserted with the vector from those not, for example, the selectable markers may be genes that confer antibiotic resistance. Signal sequences may be selected to allow the expressed polypeptide to be transported outside of the host cell.

It is within the scope of the invention to include gene segments that cause the immune effector cells of the invention, e.g., T cells, to be susceptible to negative selection in vivo. By "negative selection" is meant that the infused cell can be eliminated as a result of a change in the in vivo condition of the individual. The negative selectable phenotype may result from the insertion of a gene that confers sensitivity to an administered agent, for example, a compound. Negative selectable genes are known in the art, and include, inter alia the following: the Herpes simplex virus type I thymidine kinase (HSV-I TK) gene (Wigler et al., Cell 1 1 :223, 1977) which confers ganciclovir sensitivity; the cellular hypoxanthine phosphribosyltransferase (HPRT)gene, the cellular adenine phosphoribosyltransferase (APRT) gene, bacterial cytosine deaminase, (Mullen et al., Proc. Natl. Acad. Sci. USA. 89:33 (1992)).

In some embodiments it may be useful to include in the genetically modified immune effector cells, such as T cells, a positive marker that enables the selection of cells of the negative selectable phenotype in vitro. The positive selectable marker may be a gene which, upon being introduced into the host cell expresses a dominant phenotype permitting positive selection of cells carrying the gene. Genes of this type are known in the art, and include, inter alia, hygromycin-B phosphotransferase gene (hph) which confers resistance to hygromycin B, the amino glycoside phosphotransferase gene (neo or aph) from Tn5 which codes for resistance to the antibiotic G418, the dihydrofolate reductase (DHFR) gene, the adenosine daminase gene (ADA), and the multi-drug resistance (MDR) gene.

Preferably, the positive selectable marker and the negative selectable element are linked such that loss of the negative selectable element necessarily also is accompanied by loss of the positive selectable marker. Even more preferably, the positive and negative selectable markers are fused so that loss of one obligatorily leads to loss of the other. An example of a fused polynucleotide that yields as an expression product a polypeptide that confers both the desired positive and negative selection features described above is a hygromycin phosphotransferase thymidine kinase fusion gene (HyTK). Expression of this gene yields a polypeptide that confers hygromycin B resistance for positive selection in vitro, and ganciclovir sensitivity for negative selection in vivo. See Lupton S. D., et al, Mol. and Cell. Biology 1 1 :3374- 3378, 1991. In addition, in preferred embodiments, the polynucleotides of the invention encoding the chimeric receptors are in retroviral vectors containing the fused gene, particularly those that confer hygromycin B resistance for positive selection in vitro, and ganciclovir sensitivity for negative selection in vivo, for example the HyTK retroviral vector described in Lupton, S. D. et al. (1991), supra. See also the publications of PCT US91/08442 and PCT/US94/05601, by S. D. Lupton, describing the use of bifunctional selectable fusion genes derived from fusing a dominant positive selectable markers with negative selectable markers.

Preferred positive selectable markers are derived from genes selected from the group consisting of hph, nco, and gpt, and preferred negative selectable markers are derived from genes selected from the group consisting of cytosine deaminase, HSV-I TK, VZV TK, HPRT, APRT and gpt. Especially preferred markers are bifunctional selectable fusion genes wherein the positive selectable marker is derived from hph or neo, and the negative selectable marker is derived from cytosine deaminase or a TK gene or selectable marker.

A vector may also include materials to aid in its entry into the cell, including but not limited to a viral particle, a liposome, or a protein coating.

For cloning of the polynucleotide, the vector may be introduced into a host cell (an isolated host cell) to allow replication of the vector itself and thereby amplify the copies of the polynucleotide contained therein. The cloning vectors may contain sequence components generally include, without limitation, an origin of replication, promoter sequences, transcription initiation sequences, enhancer sequences, and selectable markers. These elements may be selected as appropriate by a person of ordinary skill in the art. For example, the origin of replication may be selected to promote autonomous replication of the vector in the host cell.

In certain embodiments, the present disclosure provides isolated host cells containing the vector provided herein. The host cells containing the vector may be useful in expression or cloning of the polynucleotide contained in the vector. Suitable host cells can include, without limitation, prokaryotic cells, fungal cells, yeast cells, or higher eukaryotic cells such as mammalian cells. Suitable prokaryotic cells for this purpose include, without limitation, eubacteria, such as Gram- negative or Gram-positive organisms, for example, Enterobactehaceae such as Escherichia, e.g., E. coli, Enterobacter, Erwinia, Klebsiella, Proteus, Salmonella, e.g., Salmonella typhimurium, Serratia, e.g., Serratia marcescans, and Shigella, as well as Bacilli such as B. subtilis and B. licheniformis , Pseudomonas such as P. aeruginosa, and Streptomyces. The vector can be introduced to the host cell using any suitable methods known in the art, including, without limitation, DEAE-dextran mediated delivery, calcium phosphate precipitate method, cationic lipids mediated delivery, liposome mediated transfection, electroporation, microprojectile bombardment, receptor-mediated gene delivery, delivery mediated by polylysine, histone, chitosan, and peptides. Standard methods for transfection and transformation of cells for expression of a vector of interest are well known in the art.

The CAR of the present invention are introduced into a host cell using transfection and/or transduction techniques known in the art. As used herein, the terms, "transfection," and, "transduction," refer to the processes by which an exogenous nucleic acid sequence is introduced into a host cell. The nucleic acid may be integrated into the host cell DNA or may be maintained extrachromosomally. The nucleic acid may be maintained transiently or a may be a stable introduction. Transfection may be accomplished by a variety of means known in the art including but not limited to calcium phosphate -DNA co-precipitation, DEAE-dextran- mediated transfection, polybrene-mediated transfection, electroporation, microinjection, liposome fusion, lipofection, protoplast fusion, retroviral infection, and biolistics. Transduction refers to the delivery of a gene(s) using a viral or retroviral vector by means of viral infection rather than by transfection. In certain embodiments, retroviral vectors are transduced by packaging the vectors into virions prior to contact with a cell. For example, a nucleic acid encoding an anti-CD37 CAR carried by a retroviral vector can be transduced into a cell through infection and pro virus integration.

As used herein, the term "genetically engineered" or "genetically modified" refers to the addition of extra genetic material in the form of DNA or RNA into the total genetic material in a cell. The terms, "genetically modified cells," "modified cells," and, "redirected cells," are used interchangeably.

In particular, the CAR of the present invention are introduced and expressed in immune effector cells so as to redirect their specificity to a target antigen of interest, e.g., CD37. An "immune effector cell," is any cell of the immune system that has one or more effector functions (e.g., cytotoxic cell killing activity, secretion of cytokines, induction of ADCC and/or CDC). The illustrative immune effector cells used with the CARs as described herein are T lymphocytes, in particular cytotoxic T cells (CTLs; CD8+ T cells) and helper T cells (HTLs; CD4+ T cells). Other populations of T cells are also useful herein, for example naive T cells and memory T cells. As would be understood by the skilled person, other cells may also be used as immune effector cells with the CARs as described herein. In particular, immune effector cells also include NK cells, NKT cells, neutrophils, and macrophages. Immune effector cells also include progenitors of effector cells wherein such progenitor cells can be induced to differentiate into an immune effector cells in vivo or in vitro. Thus, in this regard, immune effector cell includes progenitors of immune effectors cells such as hematopoietic stem cells (HSCs) contained within the CD34⁺ population of cells derived from cord blood, bone marrow or mobilized peripheral blood which upon administration in a subject differentiate into mature immune effector cells, or which can be induced in vitro to differentiate into mature immune effector cells.

As used herein, immune effector cells genetically engineered to contain CD37-specific CAR may be referred to as, "CD37-specific redirected immune effector cells."

The term, "CD34⁺ cell," as used herein refers to a cell expressing the CD34 protein on its cell surface. "CD34," as used herein refers to a cell surface glycoprotein (e.g., sialomucin protein) that often acts as a cell-cell adhesion factor and is involved in T cell entrance into lymph nodes. The CD34⁺ cell population contains hematopoietic stem cells (HSC), which upon administration to a patient differentiate and contribute to all hematopoietic lineages, including T cells, NK cells, NKT cells, neutrophils and cells of the monocyte/macrophage lineage.

The present invention provides methods for making the immune effector cells which express the CAR as described herein. In one embodiment, the method comprises transfecting or transducing immune effector cells isolated from an individual such that the immune effector cells express one or more CAR as described herein. In certain embodiments, the immune effector cells are isolated from an individual and genetically modified without further manipulation in vitro. Such cells can then be directly re-administered into the individual. In further embodiments, the immune effector cells are first activated and stimulated to proliferate in vitro prior to being genetically modified to express a CAR. In this regard, the immune effector cells may be cultured before or after being genetically modified (i.e., transduced or transfected to express a CAR as described herein).

Prior to in vitro manipulation or genetic modification of the immune effector cells described herein, the source of cells is obtained from a subject. In particular, the immune effector cells for use with the CARs as described herein comprise T cells. T cells can be obtained from a number of sources, including peripheral blood mononuclear cells, bone marrow, lymph nodes tissue, cord blood, thymus issue, tissue from a site of infection, ascites, pleural effusion, spleen tissue, and tumors. In certain embodiments, T cell can be obtained from a unit of blood collected from the subject using any number of techniques known to the skilled person, such as FICOLL™ separation. In one embodiment, cells from the circulating blood of an individual are obtained by apheresis. The apheresis product typically contains lymphocytes, including T cells, monocytes, granulocyte, B cells, other nucleated white blood cells, red blood cells, and platelets. In one embodiment, 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. In one embodiment of the invention, the cells are washed with PBS. In an alternative embodiment, the washed solution lacks calcium in may lack magnesium or may lack many if not all divalent cations. As would be appreciated by those of ordinary skill in the art, a washing step may be accomplished by methods known to those in the art, such as by using a semiautomated flowthrough centrifuge. For example, the Cobe 2991 cell processor, the Baxter CytoMate, or the like. After washing, the cells may be resuspended in a variety of biocompatible buffers or other saline solution with or without buffer. In certain embodiments, the undesirable components of the apheresis sample may be removed in the cell directly resuspended culture media.

In certain embodiments, T cells are isolated from peripheral blood mononuclear cells (PBMCs) by lysing the red blood cells and depleting the monocytes, for example, by centrifugation through a PERCOLL™ gradient. A specific subpopulation of T cells, such as CD28+, CD4+, CD8+, CD45RA+, and CD45RO+ T cells, can be further isolated by positive or negative selection techniques. For example, 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 for use herein 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 CD 14, CD20, CDl lb, CD16, HLA-DR, and CD8. Flow cytometry and cell sorting may also be used to isolate cell populations of interest for use in the present invention.

PBMC may be used directly for genetic modification with the CARs using methods as described herein. In certain embodiments, after isolation of PBMC, T lymphocytes are further isolated and in certain embodiments, both cytotoxic and helper T lymphocytes can be sorted into na^'ive, memory, and effector T cell subpopulations either before or after genetic modification and/or expansion. CD8+ cells can be obtained by using standard methods. In some embodiments, CD8+ cells are further sorted into naive, central memory, and effector cells by identifying cell surface antigens that are associated with each of those types of CD8+ cells. In embodiments, memory T cells are present in both CD62L+ and CD62L- subsets of CD8+ peripheral blood lymphocytes. PBMC are sorted into CD62L-CD8+ and CD62L+CD8+ fractions after staining with anti-CD8 and anti- CD62L antibodies. In some embodiments, the expression of phenotypic markers of central memory TCM include CD45RO, CD62L, CCR7, CD28, CD3, and CD127 and are negative for granzyme B. In some embodiments, central memory T cells are CD45RO+, CD62L+, CD8+ T cells. In some embodiments, effector T cells are negative for CD62L, CCR7, CD28, and CD 127, and positive for granzyme B and perforin. In some embodiments, naive CD 8+ T lymphocytes are characterized by the expression of phenotypic markers of naive T cells including CD62L, CCR7, CD28, CD3, CD 127, and CD45RA. In certain embodiments, CD4+ T cells are further sorted into subpopulations. For example, CD4+ T helper cells can be sorted into naive, central memory, and effector cells by identifying cell populations that have cell surface antigens. CD4+ lymphocytes can be obtained by standard methods. In some embodiments, naive CD4+ T lymphocytes are CD45RO-, CD45RA+, CD62L+ CD4+ T cell. In some embodiments, central memory CD4+ cells are CD62L positive and CD45RO positive. In some embodiments, effector CD4+ cells are CD62L and CD45RO negative.

The immune effector cells, such as T cells, can be genetically modified following isolation using known methods, or the immune effector cells can be activated and expanded (or differentiated in the case of progenitors) in vitro prior to being genetically modified. In another embodiment, the immune effector cells, such as T cells, are genetically modified with the chimeric antigen receptors described herein (e.g., transduced with a viral vector comprising a nucleic acid encoding a CAR) and then are activated and expanded in vitro. Methods for activating and expanding T cells are known in the art and are described, for example, in US6905874; US6867041 ; US6797514; WO2012079000. Generally, such methods include contacting PBMC or isolated T cells with a stimulatory agent and costimulatory agent, such as anti-CD3 and anti-CD28 antibodies, generally attached to a bead or other surface, in a culture medium with appropriate cytokines, such as IL-2. Anti-CD3 and anti-CD28 antibodies attached to the same bead serve as a "surrogate" antigen presenting cell (APC). In other embodiments, the T cells may be activated and stimulated to proliferate with feeder cells and appropriate antibodies and cytokines using methods such as those described in US6040177; US5827642; and WO2012129514.

In one embodiment, CD34+ cells are transduced with a nucleic acid construct in accordance with the invention. In certain embodiments, the transduced CD34+ cells differentiate into mature immune effector cells in vivo following administration into a subject, generally the subject from whom the cells were originally isolated. In another embodiment, CD34+ cells may be stimulated in vitro prior to exposure to or after being genetically modified with a CAR as described herein, with one or more of the following cytokines: Flt-3 ligand (FL), stem cell factor (SF), megakaryocyte growth and differentiation factor (TPO), IL-3 and IL-6 according to the methods described previously (Asheuer et al., 2004; Imren, et al., 2004).

The invention provides a population of modified immune effector cells for the treatment of cancer, the modified immune effector cells comprising a CAR as disclosed herein. For example, a population of modified immune effector cells are prepared from peripheral blood mononuclear cells (PBMCs) obtained from a patient diagnosed with B cell malignancy described herein (autologous donors). The PBMCs form a heterogeneous population of T lymphocytes that can be CD4⁺, CD8⁺, or CD4⁺ and CD8⁺. The PBMCs also can include other cytotoxic lymphocytes such as NK cells or NKT cells. An expression vector carrying the coding sequence of a chimeric protein disclosed herein can be introduced into a population of human donor T cells, NK cells or NKT cells. Successfully transduced T cells that carry the expression vector can be sorted using flow cytometry to isolate CD3 positive T cells and then further propagated to increase the number of these CAR protein expressing T cells in addition to cell activation using anti-CD3 antibodies and IL-2 or any other methods known in the art as described elsewhere herein. Standard procedures are used for cryopreservation of T cells expressing the CAR protein T cells for storage and/or preparation for use in a human subject. In one embodiment, the in vitro transduction, culture and/or expansion of T cells are performed in the absence of non-human animal derived products such as fetal calf serum and fetal bovine serum. Since a heterogeneous population of PBMCs is transduced, the resultant transduced cells are a heterogeneous population of modified cells comprising a CD37 targeting CAR as disclosed herein.

In a further embodiment, a mixture of different expression vectors can be used in genetically modifying a donor population of immune effector cells wherein each vector encodes a different chimeric antigen receptor protein as disclosed herein. The resulting transduced immune effector cells forms a mixed population of modified cells, with a proportion of the modified cells expressing more than one different CAR proteins.

In one embodiment, the invention provides a method of storing genetically modified murine, human or humanized CAR protein expressing immune effector cells which target a CD37 protein, comprising cryopreserving the immune effector cells such that the cells remain viable upon thawing. A fraction of the immune effector cells expressing the CAR proteins can be cryopreserved by methods known in the art to provide a permanent source of such cells for the future treatment of patients afflicted with the B cell malignancy. When needed, the cryopreserved transformed immune effector cells can be thawed, grown and expanded for more such cells.

As used herein, "cryopreserving," refers to the preservation of cells by cooling to sub-zero temperatures, such as (typically) 77 K or -196° C. (the boiling point of liquid nitrogen). Cryoprotective agents are often used at sub-zero temperatures to prevent the cells being preserved from damage due to freezing at low temperatures or warming to room temperature. Cryopreservative agents and optimal cooling rates can protect against cell injury. Cryoprotective agents which can be used include but are not limited to dimethyl sulfoxide (DMSO) (Lovelock and Bishop, Nature, 1959; 183 : 1394-1395; Ashwood-Smith, Nature, 1961 ; 190: 1204-1205), glycerol, polyvinylpyrrolidine (Rinfret, Ann. N.Y. Acad. Sci., 1960; 85: 576), and polyethylene glycol (Sloviter and Ravdin, Nature, 1962; 196: 48). The preferred cooling rate is 1° to 3° C/minute. After at least two hours, the T cells have reached a temperature of -80° C. and can be placed directly into liquid nitrogen (-196° C.) for permanent storage such as in a long-term cryogenic storage vessel.

The term, "substantially pure," is used to indicate that a given component is present at a high level. The component is desirably the predominant component present in a composition. Preferably it is present at a level of more than 30%, of more than 50%, of more than 75%, of more than 90%, or even of more than 95%, said level being determined on a dry weight/dry weight basis with respect to the total composition under consideration. At very high levels (e.g. at levels of more than 90%, of more than 95% or of more than 99%) the component can be regarded as being in, "pure form." Biologically active substances of the present invention (including polypeptides, nucleic acid molecules, binding agents, moieties identified/identifiable via screening, etc.) can be provided in a form that is substantially free of one or more contaminants with which the substance might otherwise be associated. Thus, for example, they can be substantially free of one or more potentially contaminating polypeptides and/or nucleic acid molecules. They can be provided in a form that is substantially free of other cell components (e.g. of cell membranes, of cytoplasm, etc.). When a composition is substantially free of a given contaminant, the contaminant will be at a low level (e.g., at a level of less than 10%, less than 5%, or less than 1 % on the dry weight/dry weight basis set out above).

CAR-expressing immune effector cells prepared as described herein can be utilized in methods and compositions for adoptive immunotherapy in accordance with known techniques, or variations thereof that will be apparent to those skilled in the art based on the instant disclosure. See, e.g., US Patent Application Publication No. 2003/0170238 to Gruenberg et al; see also US Patent No. 4,690,915 to Rosenberg.

In some embodiments, the cells are formulated by first harvesting them from their culture medium, and then washing and concentrating the cells in a medium and container system suitable for administration (a "pharmaceutically acceptable" carrier) in a treatment-effective amount. Suitable infusion medium can be any isotonic medium formulation, typically normal saline, Normosol R (Abbott) or Plasma-Lyte A (Baxter), but also 5% dextrose in water or Ringer's lactate can be utilized. The infusion medium can be supplemented with human serum albumin.

A treatment- effective amount of cells in the composition is at least 2 cells ( for example, at least 1 CD8+ central memory T cell and at least 1 CD4+ helper T cell subset) or is more typically greater than 10² cells, and up to 10⁶, up to and including 10⁸ or 10⁹ cells and can be more than 10¹⁰ cells. The number of cells will depend upon the ultimate use for which the composition is intended as will the type of cells included therein. For uses provided herein, the cells are generally in a volume of a liter or less, can be 500 mis or less, even 250 mis or 100 mis or less. Hence the density of the desired cells is typically greater than 10⁶ cells/ml and generally is greater than 10⁷ cells/ml, generally 10 cells/ml or greater. The clinically relevant number of immune cells can be apportioned into multiple infusions that cumulatively equal or exceed 10⁵, 10⁶, 10⁷, 10⁸, 10⁹, 10¹⁰, 10¹¹, or 10¹² cells. In some aspects of the present invention, particularly since all the infused cells will be redirected to a particular target antigen (e.g., CD37), lower numbers of cells, in the range of 10⁶/kilogram (10⁶-10^u per patient) may be administered. CAR expressing cell compositions may be administered multiple times at dosages within these ranges. The cells may be autologous or heterologous to the patient undergoing therapy. If desired, the treatment may also include administration of mitogens (e.g., PHA) or lymphokines, cytokines, and/or chemokines (e.g., IFN-γ, IL-2, IL-12, TNF-alpha, IL-18, and TNF-beta, GM-CSF, IL-4, IL-13, Flt3-L, RANTES, ΜΓΡΤα, etc.) as described herein to enhance induction of the immune response.

The CAR expressing immune effector cell populations of the present invention may be administered either alone, or as a pharmaceutical composition in combination with diluents and/or with other components such as IL-2 or other cytokines or cell populations. Briefly, pharmaceutical compositions of the present invention may comprise a CAR-expressing immune effector cell population, such as T cells, as described herein, in combination with one or more pharmaceutically or physiologically acceptable carriers, diluents or excipients. Such compositions may comprise buffers such as neutral buffered saline, phosphate buffered saline and the like; carbohydrates such as glucose, mannose, sucrose or dextrans, mannitol; proteins; polypeptides or amino acids such as glycine; antioxidants; chelating agents such as EDTA or glutathione; adjuvants (e.g., aluminum hydroxide); and preservatives. Compositions of the present invention are preferably formulated for intravenous administration.

As noted elsewhere with regard to in vivo selectable markers for use in the vectors encoding the CAR, adverse events may be minimized by transducing the immune effector cells containing CAR with a suicide gene, such as inducible caspase 9 (US Publ. No. 2011/0286980) or a thymidine kinase, before, after or at the same time, as the cells are transduced with the CAR construct of the present invention.

The liquid pharmaceutical compositions, whether they be solutions, suspensions or other like form, may include one or more of the following: sterile diluents such as water for injection, saline solution, preferably physiological saline, Ringer's solution, isotonic sodium chloride, fixed oils such as synthetic mono or diglycerides which may serve as the solvent or suspending medium, polyethylene glycols, glycerin, propylene glycol or other solvents; antibacterial agents such as benzyl alcohol or methyl paraben; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. The parenteral preparation can be enclosed in ampoules, disposable syringes or multiple dose vials made of glass or plastic. An injectable pharmaceutical composition is preferably sterile.

Pharmaceutical compositions of the present invention may be administered in a manner appropriate to the disease to be treated (or prevented). The quantity and frequency of administration will be determined by such factors as the condition of the patient, and the type and severity of the patient's disease, although appropriate dosages may be determined by clinical trials.

The anti-tumor immune response induced in a subject by administering CAR expressing T cells described herein using the methods described herein, or other methods known in the art, may include cellular immune responses mediated by cytotoxic T cells capable of killing infected cells, regulatory T cells, and helper T cell responses. Humoral immune responses, mediated primarily by helper T cells capable of activating B cells thus leading to antibody production, may also be induced. A variety of techniques may be used for analyzing the type of immune responses induced by the compositions of the present invention, which are well described in the art; e.g., Current Protocols in Immunology, Edited by: John E. Coligan, Ada M. Kruisbeek, David H. Margulies, Ethan M. Shevach, Warren Strober (2001) John Wiley & Sons, NY, N.Y.

As noted elsewhere, the anti-CD37 CAR-expressing immune effector cells described herein are unique in their ability to kill a target cell by two mechanisms: (i) immune effector cell mediated (e.g., T cell-mediated) and (ii) target ligand-mediated. Both immune effector cell- mediated and target ligand-mediated cell death are initiated in response to binding of the CAR to its specific ligand on the target cell. In the case of T cell-mediated killing, CAR-ligand binding initiates CAR signaling to the T cell, resulting in activation of a variety of T cell signaling pathways that induce the T cell to produce or release proteins capable of inducing target cell apoptosis by various mechanisms. These T cell-mediated mechanisms include (but are not limited to) the transfer of intracellular cytotoxic granules from the T cell into the target cell, T cell secretion of pro-inflammatory cytokines that can induce target cell killing directly (or indirectly via recruitment of other killer effector cells), and up regulation of death receptor ligands {e.g. FasL) on the T cell surface that induce target cell apoptosis following binding to their cognate death receptor (e.g. Fas) on the target cell. In the case of target ligand-mediated killing, CAR- ligand binding initiates ligand-mediated signaling in the interior of the target cell, resulting in activation of endogenous killing pathways in the target cell (e.g. those involving apoptosis or necrosis). Unlike T cell-mediated killing, target ligand-mediated killing is independent of CAR signaling and T cell activation, and is therefore likely to be resistant to the T cell-suppressive microenvironment typical of many tumors.

When "an immunologically effective amount", "effective amount", or "therapeutic amount" is indicated, the precise amount of the compositions of the present invention to be administered can be determined by a physician with consideration of individual differences in age, weight, extent of malignancy, and general condition of the patient (subject). T cell compositions may also be administered multiple times at appropriate dosages. The cells can be administered by using infusion techniques that are commonly known in immunotherapy (see, e.g., Rosenberg et al., New Eng. J. of Med. 319:1676, 1988). The optimal dosage and treatment regime for a particular patient can readily be determined by one skilled in the art of medicine by monitoring the patient for signs of disease and adjusting the treatment accordingly.

Thus the present invention provides for methods of treating an individual diagnosed with or suspected of having, or at risk of developing, a CD37-expressing cancer, comprising administering the individual a therapeutically effective amount of the CAR-expressing immune effector cells as described herein.

In one embodiment, the invention provides a method of treating a subject diagnosed with a CD37-expressing cancer comprising removing immune effector cells from a subject diagnosed with an CD37-expressing cancer, genetically modifying said immune effector cells with a vector comprising a nucleic acid encoding a chimeric antigen receptor of the instant invention, thereby producing a population of modified immune effector cells, and administering the population of modified immune effector cells to the same subject. In one embodiment, the immune effector cells comprise T cells.

In certain embodiments, the present invention also provides methods for stimulating an immune effector cell mediated immune modulatory response to a target cell population in a subject comprising the steps of administering to the subject an immune effector cell population expressing a nucleic acid construct encoding a CAR molecule.

The methods for administering the cell compositions described herein includes any method which is effective to result in reintroduction of ex vivo genetically modified immune effector cells that either directly express a CAR of the invention in the subject or on reintroduction of the genetically modified progenitors of immune effector cells that on introduction into a subject differentiate into mature immune effector cells that express the CAR. One method comprises transducing peripheral blood T cells ex vivo with a nucleic acid construct in accordance with the invention and returning the transduced cells into the subject. The term, "subject," refers to a living organism in which the immune response to the target cell population is to be induced. The subject may be mammalian including humans, agricultural and domestic animals.

In another embodiment, the invention provides genetically modified CAR expressing immune effector cells which target a CD37 protein for the treatment of hematologic malignancies, such as CLL, HCL, B cell NHL and other similar malignancies in a subject. The terms, "patient," and, "subject," are interchangeable, and, as used herein include, but are not limited to, an organism or animal; a mammal, including, e.g., a human, non-human primate, or other non-human mammal; a non-mammalian vertebrate and invertebrate.

In yet another embodiment, the invention provides genetically modified, CAR protein expressing immune effector cells which target a CD37 protein for the killing of CD37-expressing cells found in a B cell malignancy in a subject. Once the modified immune effector cells is attached to its target, it can carry out its effector function. In one embodiment, effector cell mediated mechanisms involved in target cell killing include cytotoxic T cell killing (T cell mediated killing). In another embodiment, where NK cells may be involved, the effector cell mediated mechanism involve NK cell killing. Accordingly, in one embodiment, once bound to the target cell, the modified immune effector cell can release a variety of cytotoxic factors such as perforin, granulysin, and granzyme, a serine protease, that can enter target cells via the perforin- formed pore and induce apoptosis (cell death) by activation of caspases.

In another embodiment, the present invention provides methods for treating hematologic malignancies, such as CLL, HCL, B cell NHL, comprising administering to a patient in need thereof a therapeutically effective amount of a compositions comprising the CAR-expressing immune effector cells described herein, alone or in combination with one or more therapeutic agents. Thus, the CAR-expressing immune effector cell compositions may be administered alone or in combination with other known cancer treatments, such as radiation therapy, chemotherapy, transplantation, immunotherapy, hormone therapy, photodynamic therapy, etc. The compositions may also be administered in combination with antibiotics. Such therapeutic agents may be accepted in the art as a standard treatment for a particular disease state as described herein, such as a particular cancer. Exemplary therapeutic agents contemplated include cytokines, growth factors, steroids, NSAIDs, DMARDs, anti-inflammatories, chemotherapeutics, radiotherapeutics, or other active and ancillary agents.

In certain embodiments, compositions comprising CAR-expressing immune effector cells disclosed herein may be administered in conjunction with any number of chemotherapeutic agents. Examples of chemotherapeutic agents include alkylating agents such as thiotepa and cyclophosphamide (CYTOXANTM); alkyl sulfonates such as busulfan, improsulfan and piposulfan; aziridines such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and methylamelamines including altretamine, triethylenemelamine, trietylenephosphoramide, triethylenethiophosphaoramide and trimethylolomelamine resume; nitrogen mustards such as chlorambucil, chlornaphazine, cholophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, ranimustine; antibiotics such as aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, calicheamicin, carabicin, carminomycin, carzinophilin, chromomycins, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, doxorubicin, epirubicin, esorubicin, idarubicin, marcellomycin, mitomycins, mycophenolic acid, nogalamycin, olivomycins, peplomycin, potfiromycin, puromycin, quelamycin, rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex, zinostatin, zorubicin; anti-metabolites such as methotrexate and 5- fluorouracil (5-FU); folic acid analogues such as denopterin, methotrexate, pteropterin, trimetrexate; purine analogs such as fludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidine analogs such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine, 5-FU; androgens such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, testolactone; anti-adrenals such as aminoglutethimide, mitotane, trilostane; folic acid replenisher such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elformithine; elliptinium acetate; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidamine; mitoguazone; mitoxantrone; mopidamol; nitracrine; pentostatin; phenamet; pirarubicin; podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK.RTM.; razoxane; sizofiran; spirogermanium; tenuazonic acid; triaziquone; 2, 2',2"-trichlorotriethylamine; urethan; vindesine; dacarbazine; mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine; arabinoside ("Ara-C"); cyclophosphamide; thiotepa; taxoids, e.g. paclitaxel (TAXOL®, Bristol- Myers Squibb Oncology, Princeton, NJ.) and doxetaxel (TAXOTERE®., Rhne-Poulenc Rorer, Antony, France); chlorambucil; gemcitabine; 6-thioguanine; mercaptopurine; methotrexate; platinum analogs such as cisplatin and carboplatin; vinblastine; platinum; etoposide (VP- 16); ifosfamide; mitomycin C; mitoxantrone; vincristine; vinorelbine; navelbine; novantrone; teniposide; daunomycin; aminopterin; xeloda; ibandronate; CPT-11; topoisomerase inhibitor RFS 2000; difluoromethylomithine (DMFO); retinoic acid derivatives such as Targretin™ (bexarotene), Panretin™ (alitretinoin) ; ONTAK™ (denileukin diftitox) ; esperamicins; capecitabine; and pharmaceutically acceptable salts, acids or derivatives of any of the above. Also included in this definition are anti-hormonal agents that act to regulate or inhibit hormone action on tumors such as anti-estrogens including for example tamoxifen, raloxifene, aromatase inhibiting 4(5)-imidazoles, 4-hydroxytamoxifen, trioxifene, keoxifene, LYl 17018, onapristone, and toremifene (Fareston); and anti-androgens such as flutamide, nilutamide, bicalutamide, leuprolide, and goserelin; and pharmaceutically acceptable salts, acids or derivatives of any of the above.

A variety of other therapeutic agents may be used in conjunction with the compositions described herein. In one embodiment, the composition comprising CAR-expressing immune effector cells is administered with an anti-inflammatory agent. Anti-inflammatory agents or drugs include, but are not limited to, steroids and glucocorticoids (including betamethasone, budesonide, dexamethasone, hydrocortisone acetate, hydrocortisone, hydrocortisone, methylprednisolone, prednisolone, prednisone, triamcinolone), nonsteroidal anti-inflammatory drugs (NSAIDS) including aspirin, ibuprofen, naproxen, methotrexate, sulfasalazine, leflunomide, anti-TNF medications, cyclophosphamide and mycophenolate.

Exemplary NSAIDs are chosen from the group consisting of ibuprofen, naproxen, naproxen sodium, Cox-2 inhibitors such as VIOXX® (rofecoxib) and CELEBREX® (celecoxib), and sialylates. Exemplary analgesics are chosen from the group consisting of acetaminophen, oxycodone, tramadol of proporxyphene hydrochloride. Exemplary glucocorticoids are chosen from the group consisting of cortisone, dexamethasone, hydrocortisone, methylprednisolone, prednisolone, or prednisone. Exemplary biological response modifiers include molecules directed against cell surface markers (e.g., CD4, CD5, etc.), cytokine inhibitors, such as the TNF antagonists (e.g., etanercept (ENBREL®), adalimumab (HUMIRA®) and infliximab (REMICADE®)), chemokine inhibitors and adhesion molecule inhibitors. The biological response modifiers include monoclonal antibodies as well as recombinant forms of molecules. Exemplary DMARDs include azathioprine, cyclophosphamide, cyclosporine, methotrexate, penicillamine, leflunomide, sulfasalazine, hydroxychloroquine, Gold (oral (auranofin) and intramuscular) and minocycline.

In certain embodiments, the compositions described herein are administered in conjunction with a cytokine. By "cytokine" as used herein is meant a generic term for proteins released by one cell population that act on another cell as intercellular mediators. Examples of such cytokines are lymphokines, monokines, and traditional polypeptide hormones. Included among the cytokines are growth hormones such as human growth hormone, N-methionyl human growth hormone, and bovine growth hormone; parathyroid hormone; thyroxine; insulin; proinsulin; relaxin; prorelaxin; glycoprotein hormones such as follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), and luteinizing hormone (LH); hepatic growth factor; fibroblast growth factor; prolactin; placental lactogen; tumor necrosis factor-alpha and -beta; mullerian-inhibiting substance; mouse gonadotropin-associated peptide; inhibin; activin; vascular endothelial growth factor; integrin; thrombopoietin (TPO); nerve growth factors such as NGF-beta; platelet-growth factor; transforming growth factors (TGFs) such as TGF-alpha and TGF-beta; insulin-like growth factor-I and -II; erythropoietin (EPO); osteoinductive factors; interferons such as interferon-alpha, beta, and -gamma; colony stimulating factors (CSFs) such as macrophage-CSF (M-CSF); granulocyte - macrophage-CSF (GM-CSF); and granulocyte-CSF (G-CSF); interleukins (ILs) such as IL-1, IL- lalpha, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12; IL-15, a tumor necrosis factor such as TNF-alpha or TNF-beta; and other polypeptide factors including LIF and kit ligand (KL). As used herein, the term cytokine includes proteins from natural sources or from recombinant cell culture, and biologically active equivalents of the native sequence cytokines. The following Examples illustrate embodiments of the instant disclosure. The Examples are intended to be illustrative only and are not intended to limit the scope of the present disclosure.

EXAMPLES

EXAMPLE 1 : CONSTRUCTION OF CARS

CD37-specific CARs are designed to contain CD37 scFv, a hinge and transmembrane domain from CD8a and either CD137, CD28, or both co-stimulatory domains followed by the intracellular signaling domain of the CD3ζ chain. As illustrated in FIG. 1, identical CD37 scFv with hinge and TM but lacking intracellular signal transduction domain is constructed as control (CD37-t). This control CAR could direct binding and tumor cell killing via CD37-mediated apoptosis, but not through effector T cell mediated CTL reaction. All constructs have CD8a signal peptide (SP) sequence for the surface expression on the immune effector cells.

Several different CARs are designed as shown in FIG. 1 to redirect modified T cells to CD37 expressing target cells. All these CAR constructs express single chain antibody fragment (scFv) against CD37 antigen so that modified immune effectors cells can bind to CD37-expressing targets. They differ in intracellular portion with regards to having signaling and/or co-stimulatory signaling domains. Each cDNA construct is ligated into Mlul and Kpnl sites of pBB112 lentiviral vector plasmid that contains internal promoter from the human Elongation Factor 1 a gene as shown in FIG 7 (EFlp, Genbank Accession #J04617.1 nucleotides 378-1560, Kim et al. (1990), Gene. 91(2):217-223).

CD37t CAR displays CD37 scFv protein on the cell surface but lacks a signaling molecule; hence serves as control for effector cell function. FIG. 2 shows lentiviral vector for expression of CD37t and DNA sequence is pCAR CD37t sequence set forth in SEQ ID NO: 4. Several other CD37 CAR vectors may be designed with added co-stimulatory signaling domains as shown in FIG. 1. These CAR designs incorporate one or more additional signaling motifs in addition to the CD3^ signaling domain and include CD28, CD 137, CD 134 and CD278 co-stimulatory signaling domains that provide additional co-stimulatory signals to the modified effector cells.

CD37-Z CAR in FIG. 1 shows that the CD37 scFv domain is directly fused to a hinge and transmembrane (TM) domain from human CD 8a followed by the intracellular signaling domain of human CD3ζ. The vector map is illustrated in FIG. 3 and pCAR CD37-Z polynucleotide sequence is set forth in SEQ ID NO: 5.

CD37-BZ CAR in FIG. 1 shows a coupling of the CD37scFv to the CD8a hinge and TM, followed by 4- IBB (CD 137) co-stimulatory domain and the human CD3 ζ intracellular signaling domain. This is known as, "second generation CAR," that contains one co-stimulatory domain to help proliferation of immune effector cells after engaging to the target cell binding. The cector map is illustrated in FIG. 4 and the pCAR CD37-BZ polynucleotide sequence is set forth in SEQ ID NO: 1. Similarly, another second generation CAR, CD37-28Z, contains CD28 co-stimulatory domain replacing 4-1BB portion in CD37-BZ. The vector map is in illustrated in FIG. 5 and the pCAR CD37-28Z polynucleotide sequence is set forth in SEQ ID NO: 2.

A third generation CAR, CD37-28BZ, has both CD28 and 4-1BB (CD137) co-stimulatory domains in tandem (FIG. 6). A tripartite signaling construct in this third generation CAR can improve co-stimulatory signaling of a CD37 directed human T cell exemplified by Pule et al. (Pule, M. A., et al., Mol. Ther. 12(5): 933-941, 2005). The expression vector diagram of CD37-28BZ is shown in FIG. 6 and the pCAR CD37-28BZ polynucleotide sequence is set forth in SEQ ID NO: 3. In another embodiment, recombinant retro- or lentivirus can be used to transduce immune effector cells and produce long-term expression of the chimeric protein. A simplified method for generating recombinant lentivirus vectors has been previously described (Dull et al., J. Virol., 1998; 72: 8463-8471). Recombinant retrovirus and lentivirus are generated in HEK 293 cells.

cDNA for CD37 scFv along with the CD8a hinge and TM is gene-synthesized based on the nucleotide sequences of coding region (CD37-t). To make the expression vector cassette, synthesized DNA sequences are cloned into a lentiviral expression vector containing internal EFla promoter with Mlul-Kpnl restriction enzyme.

First generation CAR that contains CD3ζ intracellular signaling domain only shows limited immune effector function due to poor proliferation upon target binding. CD3ζ domain is directly fused in frame, just before the stop codon of CD37t to generate CD37-Z CAR (first generation) whose function is directly compared with other CAR construct.

cDNA for co-stimulatory domain (CD 137 and/or CD28) either alone or in tandem are amplified by overlapping PCR and ligated to the sequence encoding the CD3ζ intracellular signaling domain. The resulting PCR products are assembled to cDNA of CD37t in frame to generate CD37-BZ (4- IBB alone), CD37-28Z (CD28 alone) and CD 37-28BZ (4- IBB and CD28), all of which are individually subcloned into EFl a lentiviral vector using Mlul- Kpnl restriction enzyme sites similar as constructing CD37t.

Table 1. Identity, Genbank Reference, Source Name and Citation for the various nucleotide segments of pCAR CD37t Lentiviral Vector

Table 2. Identity, Genbank Reference, Source Name and Citation for the various nucleotide

7947-7994 Linker Not applicable Synthetic Not Applicable

7995-8045 Accession #L09137.2

pUC19 backbone pUC19 New England Biolabs nt 2636-2686

Table 3. Identi ty, Genbank Reference, Source Name and Cita tion for the vario us nucleotide

Nucleotides Idcnlitv GeiiBank Reference Source Name Citation

Plasmid backbone, Accession #L09137.2 nt

5698-7867 pUC19 New England Biolabs contains Amp R 448-2617

7868-7870 Linker Not applicable Synthetic Not Applicable

7871-8072 SV40 ori Accession# AF403737.1 PBC12/CMV Cullen, B.R. Cell 1986 nt 2722-2923 46:973-982

8073-8120 Linker Not applicable Synthetic Not Applicable

8121-8171 pUC19 backbone Accession #L09137.2 nt pUC19 New England Biolabs

2636-2686

Table 4. Identity, Genbank Reference, Source Name and Citation for the various nucleotide

Table 5. Identity, Genbank Reference, Source Name and Citation for the various nucleotide

Table 6. Identity, Genbank Reference, Source Name and Citation for the various nucleotide

EXAMPLE 2: TRANSDUCTION OF T CELLS AND CD34+ CELL- DERIVED IMMUNE

EFFECTOR NEUTROPHILS WITH CARS AND DETECTION BY POLYMERASE CHAIN REACTION AND FLOW CYTOMETRY

Lentiviral vector (LV) supernatants are produced in HEK 293T cells as described in the literature (Naldini et al., 1996, Dull et al., 1998 and Zufferey et al., 1998). Transient transfection of 5-plasmids (HPV 275 encoding HIV gag-pol, ψΝ 15 encoding the VSV-G envelope protein, p633 encoding the HIV rev protein, HPV601 encoding the HIV tat protein, and CAR expression vector) are used as described in PCT Publ. No. WO2012/170911. LV supernatants are then concentrated by either ultracentrifugation or ion-exchange column followed by tangential flow filtration (TFF), formulated into SCGM (CellGenix Inc., DE) medium, and cryopreserved at <-70°C in single-use cryovials. Infectious titers are determined by flow cytometric analysis of transduced human osteosarcoma (HOS) cells (Kutner et al., 2009, Nature Protocols 4:495-505). For transduction of human T lymphocytes, primary human T cells are isolated from healthy volunteer donors following leukapheresis by negative selection using RosetteSep kits (Stem Cell Technologies). T cells are cultured in RPMI 1640 supplemented with 10% FCS, 100 U/ml penicillin, 100 g/ml streptomycin sulfate, 10 mM Hepes, and stimulated with magnetic beads coated with anti-CD3/anti-CD28 antibodies at a 1 :3 cell to bead ratio. For CD8 T cells, human IL-2 (Chiron) is added every other day to a final concentration of 30 IU/ml. Approximately 24 h after activation, T cells are transduced with lentiviral vectors at an MOI of 5. Transduction of T cells is evaluated by polymerase chain reaction using primers specific to the viral vector and by flow cytometry using anti-idiotypic antibodies to CD37 (Heider, et al., 2011) 7 to 10 days following transduction.

For transduction of human hematopoietic stem cells, fresh human bone marrow (BM)

CD34+ cells (Lonza, Walkersville, MD) or human G-CSF mobilized peripheral blood (mPB) CD34+ cells (AllCells, LLC, Emeryville, CA) are obtained, washed and cultured for 18 hours in SCGM supplemented with human recombinant IL-3 (60 ng/ml), Flt-3L (100 ng/ml), TPO (100 ng/ml) and SCF (100 ng/ml) (Peprotech) at a cell concentration of 1 x 106 cells/mL (pre- stimulation process). Cells are then washed with SCGM, and resuspended in 200 μΐ_^ volumes in SCGM (mock control) or supernatant containing purified LV CARs supplemented with the same concentrations of cytokines and 8 μg/ml protamine sulfate. Transduction of CD34+ cells are evaluated by polymerase chain reaction using primers specific to the viral vector and by flow cytometry using anti-idiotypic antibodies to CD37 (Heider, et al., 2011) one to two weeks following transduction.

Transduced immune effector neutrophils derived from CD34+ cells are expanded and differentiated into neutrophils utilizing the following schedule of cytokine treatment: during days 1 to 6, the cells are cultured in human SCF (100 ng/ml), human IL-3 (50 ng/ml), and human IL-6 (10 ng/ml). On days 7, 9, and 11, fresh human SCF (10 ng/ml) and human granulocyte CSF (G-CSF) (2 ng/ml) are added to the cultures. On days 14 and 16, cells are fed with G-CSF (10 ng/ml) alone. On days 18 to 22, cells are harvested, analyzed via cytospin preparations and flow cytometry, and utilized in chromium release cytotoxicity assays as described below.

EXAMPLE 3 : KILLING OF ANTIGEN POSITIVE, BUT NOT ANTIGEN NEGATIVE TARGETS

THROUGH T CELL KILLING MECHANISMS

The ability of CAR expressing T cells or neutrophil immune effector cells derived from transduced CD34+ cells to lyse tumor target cells is measured using a standard 51Cr-release assay. Raji, RAMOS and Daudi cells are used as antigen positive targets and WAC cells are used as antigen negative targets. These cells are characterized for CD37 antigen expression by flow cytometry (Zhao et al., 2012). Cell lines are labeled with sodium [51Cr]chromate (100 mCi/106 cells) for 3 h at 37°C and washed three times.

Labeled target cells are then incubated with effector cells as described below. The percentage of specific lysis are calculated from triplicate samples using the following formula: [(CPM-SR)/(MR-SR)]3 X 100, where CPM is the counts per min released by targets incubated with effector cells, MR is the counts per min released by targets lysed with 100 ml of 1% Triton X- 100, and SR is the counts per min released by targets incubated with medium alone. In vitro differentiated human neutrophils are harvested at day 21 post cytokine or transduced human T cells are harvested after culture for 14 days. The next day, cells are analyzed via cytospin preparations and flow cytometry, and utilized in a 51Cr release cytotoxicity assay as described above. Briefly, human neutrophils or T cells (control and CAR expressing) are resuspended in 100 ml of assay medium (RPMI, 10% FCS, 20 ng/ml human granulocyte-macrophage-CSF for neutrophils and RPMI, 10% FCS, 20 IU/ml human IL2 for T cells) and plated in triplicate in 96-well plates. To each well, 105 51Cr-labeled targets are added in 100 ml of assay medium to establish a range of E:T ratios. To measure Ab-dependent cellular cytotoxicity (ADCC), polyclonal rabbit anti-human lymphocyte serum (Cedar Lane) (5 mg/ml) is added to control cells. The assay is initiated by centrifugation (2 min, 20°C) and allowed to incubate at 37°C for 5 h. From each well, 100 ml of supernatant are removed and counted in a gamma counter for the assessment of 51Cr release.

EXAMPLE 4: ANTIGEN DRIVEN PROLIFERATION AND CYTOKINE PRODUCTION

Production of pro-inflammatory cytokines in an antigen specific fashion is a hallmark of an immune response to cancer. The ability of CAR expressing T cells to produce pro- inflammatory/anti-tumor cytokines in response to contact with tumor targets in response to antigen positive tumor cells compared to controls is evaluated in cytokine release assays. Raji, RAMOS and Daudi cells are used as antigen positive targets. WAC cells are used as antigen negative targets and K562 cells are used to assess non-specific lysis. Together, these antigen positive and antigen negative cells enable the assessment of the specificity of cytokine production in response to antigen.

CAR-expressing T cells are prepared as described in Example 3 and exposed to antigen positive or antigen negative tumor cells for 24 hours as described previously (Zhao et al., 2010). Commercially available ELISA kits (R&D S ystems Inc.) that assess IFN-a, IL-2 and TNF-a production are used to measure the production of these THl cytokines produced by tumor specific THl CD8+ antigen-specific T cells in response to engagement of the native T cell receptor by antigen. In response to antigen positive tumor cells, T cells expressing the CD37 targeted CAR will induce cytokine production approximately 5 - 10 fold in the presence of antigen positive targets compared to antigen negative targets of K562 cells as described for other CAR T cells (Zhao et al., 2009, Milone et al., 2009) .

EXAMPLE 5: KILLING BY ACTIVATION INHIBITED T CELLS : KILLING IN THE PRESENCE

OF FK506, CSA OR RAPAMYCIN OR IN THE PRESENCE OF TGF-BETA

It is well known that TGF-β produced in the microenvironment of tumors is immunosuppressive (reviewed by Yang, Curr. Mol. Med. 3210; 10: 374-380). Recent studies demonstrate that naive peripheral CD4+CD252Foxp32 T cells can be converted into CD4+CD25+Foxp3+ T regs by TGF-β in the context of TCR signaling and co-stimulation (Chen et al., J. Exp. Med. 2003; 198: 1875-1886). Regulatory T cells suppress tumor-specific CD8 T cell cytotoxicity through TGF-β signaling in vivo in mice (Chen et al., 2003). However, to mimic the tumor suppressive microenvironment in vitro with human T cells, the pharmacologic agent ciclosporin is used to suppress T cell activation.

Engagement of antigen by the T cell receptor complex and co-stimulation through CD28, activation of the T cell receptor normally increases intracellular calcium, which acts via calmodulin to activate calcineurin. Calcineurin then dephosphorylates the transcription nuclear factor of activated T cells (NFATc), which moves to the nucleus of the T cell and increases the activity of genes coding for IL-2 and related cytokines to initiate the cascade of T cell activation. Ciclosporin binds to the cytosolic protein cyclophilin (immunophilin) of lymphocytes, especially T cells. This complex of ciclosporin and cyclophilin inhibits calcineurin, which, under normal circumstances, is responsible for activating the transcription of interleukin 2. In T cells ciclosporin prevents the dephosphorylation of NF-AT by binding to cyclophilin. It also inhibits lymphokine production and interleukin release and, therefore, leads to a reduced function of effector T cells, similar to the effect of regulatory T cells.

To demonstrate that CD37 CAR T cells can mediate killing of tumor targets in the presence of a tumor suppressive microenvironment by cross linking of CD37 molecules on the surface of antigen positive tumor cells, analogous to the ability of

CD37 antibodies ability to kill antigen positive tumor cells in the absence of ADCC (Zhao et al., 2010), the CTL assay carried out in Example 3 is repeated with the same samples where the effector cells are treated in the presence or absence of ciclosporin for 24 hrs prior to incubation with labeled targets in the CTL assay. Ciclosporin treated CAR T cells kill antigen positive targets as effectively as untreated CAR T cells. Antigen negative targets are not killed by either ciclosporin treated or non-treated CAR T cells.

To demonstrate the immunosuppressive effects of ciclosporin, the cytokine production assay described in Example 4 is carried out using CAR transduced T cells in the absence or presence of ciclosporin. CAR T cells not treated with ciclosporin are able to activate cytokine production (IL-2, interferon-γ and TNF-a) in the presence of antigen positive tumor cells. Ciclosporin-treated effector cells fail to activate as evidenced by failure to produce IL-2, interferon- γ and TNF-a upon antigen activation by incubation with antigen positive target cells. As a control, antibody to CD37 is able to kill labeled antigen positive target cells in the presence or absence of NK cells and in the presence or absence of ciclosporin (Zhao et al., 2010). These studies demonstrate that CAR targeted T cells can mediate their cytolytic activity through CD37 CAR clustering of CD 37 target antigen on tumor cells in the presence of ciclosporin which mimics the tumor suppressive microenvironment.

It will be appreciated that various features of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art, which are also intended to be encompassed by the following claims. Unless specifically recited in a claim, steps or components of claims should not be implied or imported from the specification or any other claims as to any particular order, number, position, size, shape, angle, color or material.

The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent application, foreign patents, foreign patent application and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirely. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, application and publications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.

Claims

CLAIMS What is claimed is:

1. A nucleic acid construct encoding a chimeric immune receptor, wherein said chimeric immune receptor binds an antigen on a target tumor cell, wherein upon introduction of said nucleic acid construct into an immune effector cell, said immune effector cell expresses the chimeric immune receptor and mediates direct killing of the target tumor cell through clustering of the antigen on the target tumor cell surface upon engagement of the antigen in the presence of an immune suppressive tumor microenvironment.

2. A bifunctional chimeric antigen receptor, wherein the bifunctional chimeric antigen receptor binds an antigen on a target cell surface, and is able to both induce apoptosis in the target cell by direct engagement of the antigen on the cell surface as well as mediate T cell activation and death of the target cell through T cell cytolytic activity.

3. The nucleic acid construct of claim 1, wherein said antigen is CD37.

4. The nucleic acid construct of claim 1, which encodes a CD37 antigen specific chimeric antigen receptor comprising an extracellular domain comprising a binding domain that binds the CD37 antigen, a transmembrane domain, an intracellular signaling domain, and optionally one or more co-stimulatory signaling domains.

5. The nucleic acid construct of claim 4, further comprising a hinge region.

6. The nucleic acid construct of claim 4, wherein said transmembrane domain is a transmembrane domain derived from a protein selected from the group consisting of ΟΌ3ζ, CD28, CD4 and CD8a.

7. The nucleic acid construct of claim 4, wherein said co-stimulatory signaling domain is derived from a protein selected from the group consisting of CD137, CD28, CD134 and CD278.

8. The nucleic acid construct of claim 5, wherein said hinge region is derived from a protein selected from the group consisting of CD8a, CD4, CD28 and CD7.

9. The nucleic acid construct of claim 4, wherein said binding domain is an antibody or an antigen-binding fragment thereof.

10. The nucleic acid construct of claim 9, wherein the antibody or antigen-binding fragment thereof is selected from the group consisting of a human antibody, a murine antibody, a humanized antibody and a single chain antibody.

11. The nucleic acid construct of claim 10, wherein said single chain antibody is linked to at least part of the constant region of an IgGl or IgG4.

12. The nucleic acid construct of claim 11, wherein said constant region of said IgGl has a G237A mutation.

13. A vector comprising the nucleic acid construct of any one of claims 1 and 3-12.

14. The vector of claim 13, wherein the vector is an expression vector.

15. The vector of claim 13, wherein the vector is a viral vector.

16. The vector of claim 15, wherein the viral vector is a lentiviral vector or a retroviral vector.

17. The vector of claim 16 wherein the lentiviral vector is derived from a virus selected from the group consisting of HIV1, EIAV, FIV and Foamy Virus.

18. An immune effector cell comprising the vector of claim 13.

19. The immune effector cell of claim 18, wherein the immune effector cell is a T lymphocyte.

20. A composition comprising the immune effector cell of claim 18 or 19 and a physiologically acceptable excipient.

21. A method of generating a CD37-specific immune effector cells comprising introducing into an immune effector cell the vector of claim 13, stimulating the cells and inducing the cells to proliferate by contacting the cells in the presence of IL2 with antibodies that bind CD3 and antibodies that bind to CD28; thereby generating the CD37-specific immune effector cell.

22. The method of claim 15 wherein the immune effector cells are stimulated and induced to proliferate before introducing the vector.

23. The method of claim 15 wherein the immune effector cells of T lymphocytes.

24. A method of making a CD37 specific immune effector cell, comprising isolating CD34+ cells from bone marrow, cord blood or mobilized peripheral blood from a subject, and introducing the vector of claim 13 into the isolated CD34+ cells.

25. The method of claim 24, where said CD34+ cells are pre-stimulated with one or more cytokines selected from the group consisting of FLT3 ligand, TPO, SCF, IL-3 and IL-6 before introducing the vector of claim 13.

26. A method of treating a B cell malignancy in a subject in need thereof, comprising administering to the subject a therapeutically effect amount of the composition of claim 19 or 20.