WO2024007671A1

WO2024007671A1 - Antibody specifically binding to cd24 and use thereof

Info

Publication number: WO2024007671A1
Application number: PCT/CN2023/088389
Authority: WO
Inventors: 杜靓; 张红艳; 金理娜; 陈亚莉; 徐溜溜; 郭晓月; 万婷婷; 金夷
Original assignee: 上海吉倍生物技术有限公司
Priority date: 2022-07-07
Filing date: 2023-04-14
Publication date: 2024-01-11
Also published as: WO2024007672A1

Abstract

Provided are an anti-CD24 antibody or an antigen-binding fragment thereof, a nucleic acid molecule, a vector and a host cell encoding the antibody or the antigen-binding fragment thereof, a derivative of the antibody or the antigen-binding fragment thereof, and use thereof for disease treatment.

Description

Antibodies that specifically bind CD24 and their uses

Technical field

The present invention relates to the fields of disease treatment and immunology. Specifically, the present invention relates to anti-CD24 antibodies or antigen-binding fragments thereof, nucleic acid molecules, vectors and host cells encoding the antibodies or antigen-binding fragments thereof, the antibodies or antigen-binding fragments thereof, Derivatives of antigen-binding fragments, and their use in the treatment of disease.

Background technique

Macrophages are an important part of innate immunity. They phagocytose aging and dead cells in the human body and play a role in cleaning the body. In recent years, the role of innate immunity in anti-tumor has received much attention, especially macrophages, which can clear tumor cells through phagocytosis in tumor tissues and present tumor cell-related antigens on their surfaces to further activate the immune system.

CD47 is a target related to macrophage immune activation. As research continues to deepen, multiple CD47 monotherapy and combination therapies have entered the clinical trial stage. Among them, FortySeven's Hu5F9 is currently in clinical phase III, and another 5 drugs are in clinical trials. Phase II experiment (Zhongxing Jiang, et al: Targeting CD47 for cancer immunotherapy. J. Hematol. Oncol. 2021; 14:180-202.). Clear single-agent efficacy has been observed for drugs targeting this target in the clinical stage. However, the high expression of this target in red blood cells raises an important safety issue. Drugs targeting CD47 may destroy red blood cells and cause severe hematological toxicity, triggering Side effects such as anemia and thrombocytopenia (Zhongxing Jiang, et al: Targeting CD47 for cancer immunotherapy. J. Hematol. Oncol. 2021; 14:180-202.).

CD24 is a highly glycosylated glycolphosphatidylinositol (GPI)-anchored cell surface protein. Highly glycosylated CD24 is anchored on lipid rafts in the cell membrane through glycosyl-phosphatidyl-inositol (GPI). It serves as a mediator of intermolecular interactions at cell junction sites, mediating intercellular, cell-to-cell interactions. and matrix adhesion. CD24 is involved in cell recognition, activation, signal transduction, cell proliferation and differentiation, cell stretching and movement, etc. CD24 interacts with siglec10 on macrophages of the innate immune system to inhibit destructive inflammatory responses to infection, sepsis, liver injury, and chronic graft-versus-host disease (Guo-Yun Chen, et al: CD24and Siglec-10Selectively Repress Tissue Damage-Induced Immune Responses.Science2009;323(5922):1722–1725.).

CD24 is a signaling protein similar to CD47 that is overexpressed in a variety of human cancers and its receptor Siglec-10 Expressed on tumor-associated macrophages, CD24 binds to Siglec-10 on the surface of tumor-associated macrophages, activating the SHP-1/SHP-2-mediated inhibitory signaling pathway, thereby blocking Toll-like receptor-mediated inflammation. And the cytoskeletal rearrangement required by macrophage phagocytes causes the suppression of macrophages in the tumor microenvironment and achieves tumor immune escape (Amira A. Barkal, et al: Weissman CD24 signaling through macrophage Siglec-10 is a target for cancer. Immunotherapy 2019; 572:392-399.; Shan-Shan Yin, et al: Molecular Mechanism of Tumor Cell Immune Escape Mediated by CD24/Siglec-10. Front. Immunol. 2020; 11:1324.). Knocking out CD24 or Siglec-10, as well as using CD24 monoclonal antibodies to block the interaction of CD24 with Siglec-10, robustly enhanced the phagocytosis of all CD24-expressing human tumor cells by macrophages in the experiment. In mice transplanted with human cancer cells, blocking CD24 restored macrophage attack on cancer (Amira A. Barkal, et al: Weissman CD24 signaling through macrophage Siglec-10 is a target for cancer. Immunotherapy 2019; 572 :392-399.). These evidences indicate that CD24 is a very promising new target for immunotherapy, and CD24 antibodies are expected to become a new force in the macrophage immune checkpoint inhibitor family.

Contents of the invention

The inventor of the present application has developed a monoclonal antibody with high affinity for cell surface CD24 after extensive research. The antibody of the present invention can effectively block the binding of CD24 and its ligand (such as Siglec-10), thereby releasing the immunosuppressive signaling pathway mediated by SHP-1/SHP-2 and inducing the phagocytosis of tumor cells by macrophages. . Therefore, the antibody of the present invention has the potential to be used to treat CD24-expressing tumors and has significant clinical value.

Antibodies of the invention

In a first aspect, the invention provides an antibody or an antigen-binding fragment thereof capable of specifically binding to CD24, the antibody or an antigen-binding fragment thereof comprising:

A repeat containing a VH CDR1 as set forth in SEQ ID NO:3 or a variant thereof, a VH CDR2 as set forth in SEQ ID NO:4 or a variant thereof, and a VH CDR3 as set forth in SEQ ID NO:5 or a variant thereof Chain variable region (VH); and/or, comprising VL CDR1 as set forth in SEQ ID NO:6 or a variant thereof, VL CDR2 as set forth in SEQ ID NO:7 or a variant thereof, and SEQ ID NO: The light chain variable region (VL) of the VL CDR3 shown in 8 or a variant thereof;

Wherein, the variant has one or several amino acid substitutions, deletions or additions (for example, 1, 2 or 3 amino acid substitutions, deletions or additions) compared to the sequence from which it is derived.

In certain embodiments, the substitutions are conservative substitutions.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises:

(a) The following three heavy chain variable region CDRs: VH CDR1 as shown in SEQ ID NO:3, VH CDR2 as shown in SEQ ID NO:4, and VH CDR3 as shown in SEQ ID NO:5; and/or, the following three light chain variable region CDRs: VL CDR1 as shown in SEQ ID NO:6, VL CDR2 as shown in SEQ ID NO:7, VL CDR3 as shown in SEQ ID NO:8 ;or,

(b) The following three heavy chain variable region CDRs: VH CDR1, VH CDR2 and VH CDR3 contained in the heavy chain variable region shown in SEQ ID NO: 1 or 9; and/or, the following three light Chain variable region CDRs: VL CDR1, VL CDR2 and VL CDR3 contained in the light chain variable region shown in SEQ ID NO: 2 or 10.

In certain embodiments, the three CDRs contained in the heavy chain variable region and the three CDRs contained in the light chain variable region are defined by the Kabat, Chothia or IMGT numbering system.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises: a heavy chain variable region (VH) comprising the sequence set forth in SEQ ID NO: 1 or a variant thereof; and/or comprising SEQ ID NO: The light chain variable region (VL) of the sequence shown in 2 or a variant thereof;

Wherein, the variant has one or several amino acid substitutions, deletions or additions compared to the sequence from which it is derived (for example, 1, 2, 3, 4 or 5 amino acid substitutions, deletions or additions) , or have at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% , or a sequence with 100% sequence identity.

In certain embodiments, the substitutions are conservative substitutions.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises: a VH comprising the sequence set forth in SEQ ID NO: 1 and a VL comprising the sequence set forth in SEQ ID NO: 2.

In certain embodiments, the antibody or antigen-binding fragment thereof is humanized.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises a framework region sequence derived from a human immunoglobulin, which framework region may optionally comprise one or more (e.g., 1, 2, 3 , 4, 5, 6, 7, 8, 9 or 10) back mutations from human residues to the corresponding murine residues.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises: a heavy chain framework region sequence derived from a human heavy chain germline sequence (i.e., an amino acid sequence encoded by a human heavy chain germline gene), and a heavy chain framework sequence derived from A light chain framework region sequence of a human light chain germline sequence (i.e., an amino acid sequence encoded by a human light chain germline gene), the heavy chain framework region and/or the light chain framework region optionally comprising one or more ( For example, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10) back mutations from a human residue to the corresponding murine residue.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises: a heavy chain variable region (VH) comprising the sequence set forth in SEQ ID NO: 9 or a variant thereof; and/or comprising SEQ ID NO: The light chain variable region (VL) of the sequence shown in 10 or a variant thereof; wherein the variant has one or several amino acid substitutions, deletions or additions (e.g. 1, 2, 3, 4 or 5 amino acid substitutions, deletions or additions), or having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, Sequences that have at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity. In certain embodiments, the substitutions are conservative substitutions.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises: a VH comprising the sequence set forth in SEQ ID NO: 9 and a VL comprising the sequence set forth in SEQ ID NO: 10.

In certain embodiments, the antibodies of the invention, or antigen-binding fragments thereof, may further comprise a constant region derived from a mammalian (eg, murine or human) immunoglobulin. In certain embodiments, the heavy chain of the antibody or antigen-binding fragment thereof comprises a heavy chain constant derived from a mammalian (e.g., murine or human) immunoglobulin (e.g., IgG, such as IgG1, IgG2, IgG3, or IgG4). region, the light chain of the antibody or antigen-binding fragment thereof comprises a light chain constant region derived from a mammalian (eg, murine or human) immunoglobulin (eg, kappa or lambda).

In certain embodiments, the heavy chain of the antibody or antigen-binding fragment thereof of the invention comprises the heavy chain constant region (CH) of a human immunoglobulin or a variant thereof that has a Substitution, deletion or addition of one or more amino acids (e.g., substitution, deletion, or addition of up to 20, up to 15, up to 10, or up to 5 amino acids; for example, 1, 2, 3, 4 or substitution, deletion or addition of 5 amino acids); and/or,

The light chain of the antibody or antigen-binding fragment thereof of the invention comprises the light chain constant region (CL) of a human immunoglobulin or a variant thereof having one or more amino acid substitutions compared to the sequence from which it is derived. , deletion or addition (for example, substitution, deletion or addition of up to 20, up to 15, up to 10, or up to 5 amino acids; for example, substitution of 1, 2, 3, 4 or 5 amino acids, missing or added).

In some embodiments, the variant of the heavy chain constant region (CH) may have one or more conservative amino acid substitutions compared to the wild-type sequence from which it is derived. In such embodiments, the variant of the heavy chain constant region (CH) may have the same or substantially the same effector function as the wild-type sequence from which it is derived.

In other embodiments, the variant of the heavy chain constant region (CH) may comprise one or more amino acid mutations compared to the wild-type sequence from which it is derived to alter one or more of the following of the antibodies of the invention Characteristics: Fc receptor binding, antibody glycosylation, number of cysteine residues, effector cell function or complement function, etc. Functional changes can be produced by replacing at least one amino acid residue with a different residue in the constant region of the antibody, e.g., altering the effector response of the antibody to Affinity for a ligand (e.g. FcR or complement C1q), thereby altering (e.g. reducing) effector function. The Fc region of antibodies mediates several important effector functions, such as ADCC, phagocytosis, CDC, etc.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises a constant region derived from a human immunoglobulin. In certain embodiments, the heavy chain of the antibody or antigen-binding fragment thereof comprises a heavy chain constant region derived from a human immunoglobulin (e.g., IgGl, IgG2, IgG3, or IgG4), the antibody or antigen-binding fragment thereof The light chain includes a light chain constant region derived from a human immunoglobulin (eg, kappa or lambda).

In certain embodiments, the antibody or antigen-binding fragment thereof comprises the heavy chain constant region (CH) set forth in SEQ ID NO: 11.

In certain embodiments, the antibody or antigen-binding fragment thereof comprises the light chain constant region (CL) set forth in SEQ ID NO: 12.

In certain embodiments, the antigen-binding fragment is selected from the group consisting of Fab, Fab', (Fab') ₂ , Fv, disulfide-linked Fv, scFv, diabodies, and single domain antibodies (sdAb). In certain embodiments, the antibody is a murine antibody, a chimeric antibody, a humanized antibody, a bispecific antibody, or a multispecific antibody.

In the present invention, the antibodies or antigen-binding fragments thereof of the invention may include variants that differ from the antibodies or antigen-binding fragments thereof from which they are derived by only one or more (e.g., up to 20 conservative substitutions of amino acid residues), or have at least 85%, at least 90%, or at least 95% similarity with the antibody or antigen-binding fragment thereof from which it is derived , at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity, and substantially retains the biological function of the antibody or antigen-binding fragment thereof from which it is derived (e.g., specific binding to CD24 , blocking activity that blocks the binding of CD24 to its ligand (e.g., Siglec-10)).

Preparation of antibodies

The antibodies of the present invention can be prepared by various methods known in the art, such as by genetic engineering and recombinant technology. For example, DNA molecules encoding the heavy chain and light chain genes of the antibody of the present invention are obtained by chemical synthesis or PCR amplification. The resulting DNA molecule is inserted into an expression vector and then transfected into host cells. Then, the transfected host cells are cultured under specific conditions and express the antibody of the invention.

The antigen-binding fragments of the present invention can be obtained by hydrolyzing intact antibody molecules (see Morimoto et al., J. Biochem. Biophys. Methods 24:107-117 (1992) and Brennan et al., Science 229:81 (1985)) . Alternatively, these antigen-binding fragments can also be produced directly from recombinant host cells (reviewed in Hudson, Curr. Opin. Immunol. 11:548-557 (1999); Little et al., Immunol. Today, 21:364-370 (2000)). For example, Fab′ fragments can be obtained directly from host cells; Fab′ fragments can be chemically coupled to form F(ab′) ₂ fragments (Carter et al., Bio/Technology, 10:163-167 (1992)). In addition, Fv, Fab or F(ab') ₂ fragments can also be directly isolated from the recombinant host cell culture medium. Those of ordinary skill in the art are well aware of other techniques for preparing such antigen-binding fragments.

In a second aspect, the invention provides an isolated nucleic acid molecule comprising a nucleotide sequence encoding an antibody of the invention or an antigen-binding fragment thereof, or a heavy chain variable region and/or a light chain variable region thereof. In certain embodiments, the isolated nucleic acid molecule encodes an antibody of the invention, or an antigen-binding fragment thereof, or a heavy chain variable region and/or a light chain variable region thereof.

In certain embodiments, the isolated nucleic acid molecule comprises a first nucleotide sequence encoding a heavy chain variable region of an antibody of the invention or an antigen-binding fragment thereof, and/or encoding an antibody of the invention or an antigen-binding fragment thereof The second nucleotide sequence of the light chain variable region of the fragment.

In certain embodiments, the isolated nucleic acid molecule comprises a first nucleotide sequence encoding a heavy chain of an antibody of the invention or an antigen-binding fragment thereof, and/or a first nucleotide sequence encoding a light chain of an antibody of the invention or an antigen-binding fragment thereof. The second nucleotide sequence of the chain.

In a third aspect, the invention provides a vector (eg, a cloning vector or an expression vector) comprising an isolated nucleic acid molecule of the invention. In certain embodiments, vectors of the invention are, for example, plasmids, cosmids, phages, and the like. In certain embodiments, the vector is capable of expressing an antibody of the invention or an antigen-binding fragment thereof in a subject (eg, a human).

In a fourth aspect, the invention provides a host cell comprising an isolated nucleic acid molecule or vector as described above. Such host cells include, but are not limited to, prokaryotic cells such as E. coli cells, and eukaryotic cells such as yeast cells, insect cells, plant cells, and animal cells (such as mammalian cells, such as mouse cells, human cells, etc.).

In another aspect, a method for preparing an antibody or an antigen-binding fragment thereof of the present invention is provided, comprising culturing a host cell as described above under conditions that allow expression of the antibody or an antigen-binding fragment thereof, and from the cultured The antibody or antigen-binding fragment thereof is recovered in host cell culture.

derived antibodies

The antibodies of the invention, or antigen-binding fragments thereof, may be derivatized, eg, linked to another molecule (eg, another polypeptide or protein). Generally, derivatization (e.g., labeling) of an antibody or antigen-binding fragment thereof does not adversely affect its ability to CD24 binding. Therefore, the antibodies or antigen-binding fragments thereof of the invention are also intended to include such derivatized forms. For example, an antibody of the invention or an antigen-binding fragment thereof can be functionally linked (by chemical coupling, genetic fusion, non-covalent linkage, or other means) to one or more other molecular groups, such as another antibody (e.g., forming Bispecific antibodies), detection reagents, pharmaceutical reagents, and/or proteins or polypeptides capable of mediating the binding of an antibody or antigen-binding fragment to another molecule (e.g., avidin or polyhistidine tags). In addition, the antibodies of the invention or antigen-binding fragments thereof can also be derivatized with chemical groups, such as polyethylene glycol (PEG), methyl or ethyl groups, or sugar groups. These groups can be used to improve the biological properties of the antibody, such as increasing serum half-life.

labeled antibodies

In certain embodiments, the antibodies of the invention, or antigen-binding fragments thereof, bear a detectable label, such as an enzyme, a radionuclide, a fluorescent dye, a luminescent substance (eg, a chemiluminescent substance), or biotin. The detectable label of the present invention can be any substance detectable by fluorescence, spectroscopy, photochemistry, biochemistry, immunology, electrical, optical or chemical means. Such labels are well known in the art and examples include, but are not limited to, enzymes (e.g., horseradish peroxidase, alkaline phosphatase, beta-galactosidase, urease, glucose oxidase, etc.), radionuclides fluorescein (e.g., ^3H , ^125I , ^35S , ^14C , or ^32P ), fluorescent dyes (e.g., fluorescein isothiocyanate (FITC), fluorescein, tetramethylrhodamine isothiocyanate (TRITC) , Phycoerythrin (PE), Texas Red, rhodamine, quantum dots or cyanine dye derivatives (such as Cy7, Alexa 750)), luminescent substances (such as chemiluminescent substances, such as acridinium ester compounds), Magnetic beads (e.g., ), calorimetric labels such as colloidal gold or colored glass or plastic (e.g., polystyrene, polypropylene, latex, etc.) beads, and avidin modified to bind the above labels (e.g., streptavidin ) of biotin. Detectable labels as described above can be detected by methods known in the art. For example, radioactive labels can be detected using photographic film or a scintillation calculator, and fluorescent labels can be detected using a light detector to detect the emitted light. Enzyme markers are generally detected by providing a substrate to the enzyme and detecting the reaction product produced by the enzyme's action on the substrate, and thermometric markers are detected by simply visualizing a colored marker. In certain embodiments, such labels can be adapted for immunological detection (eg, enzyme-linked immunoassay, radioimmunoassay, fluorescent immunoassay, chemiluminescence immunoassay, etc.). In certain embodiments, detectable labels as described above can be linked to the antibodies or antigen-binding fragments thereof of the invention via linkers of varying lengths to reduce potential steric hindrance.

Bispecific or multispecific molecules

The antibodies of the invention, or antigen-binding fragments thereof, can be used to form bispecific or multispecific molecules. The antibodies of the invention or antigen-binding fragments thereof may be part of a bispecific or multispecific molecule that The specificity molecule contains a second functional moiety (eg, a second antibody) with a different binding specificity than the antibody or antigen-binding fragment thereof of the invention, thereby being able to bind to at least two different binding sites and/or target molecules. For example, an antibody or antigen-binding fragment thereof of the invention may be linked to a second antibody or antigen-binding fragment thereof capable of specifically binding to any protein that may be used as a potential target for combination therapy. To generate such bispecific or multispecific molecules, the antibodies of the invention or antigen-binding fragments thereof may be linked (e.g., by chemical coupling, genetic fusion, non-covalent association, or other means) to one or more other Binding molecules (eg, additional antibodies, antibody fragments, peptides, or binding mimetics).

Accordingly, in a fifth aspect, the invention provides a bispecific or multispecific molecule comprising an antibody of the invention or an antigen-binding fragment thereof.

In certain embodiments, the bispecific or multispecific molecule specifically binds CD24 and additionally specifically binds one or more other targets.

In certain embodiments, the bispecific or multispecific molecule further comprises at least one molecule (eg, a second antibody) having a second binding specificity for a second target.

Immunoconjugate

The antibodies of the invention, or antigen-binding fragments thereof, can be linked to therapeutic agents to form immunoconjugates. Because immunoconjugates have the ability to selectively deliver one or more therapeutic agents to target tissues (e.g., CD24-expressing cells), immunoconjugates can improve the performance of the antibodies of the invention or antigen-binding fragments thereof in treating diseases (e.g., CD24-expressing cells). therapeutic efficacy in cancer).

In a sixth aspect, the invention provides immunoconjugates comprising an antibody of the invention, or an antigen-binding fragment thereof, and a therapeutic agent linked to the antibody or antigen-binding fragment thereof.

In certain embodiments, the immunoconjugate is an antibody-drug conjugate (ADC).

In certain embodiments, the therapeutic agent is a cytotoxic agent. In the present invention, the cytotoxic agent includes any agent that is harmful to cells (eg, kills cells).

In certain embodiments, the therapeutic agent is selected from the group consisting of alkylating agents, mitotic inhibitors, anti-tumor antibiotics, antimetabolites, topoisomerase inhibitors, tyrosine kinase inhibitors, radionuclide agents, and random combination.

In certain embodiments, the antibodies of the invention, or antigen-binding fragments thereof, are conjugated to the therapeutic agent, optionally via a linker.

In the present invention, the cytotoxic agent can be coupled to the antibody of the invention or its anti- Original binding fragment. Examples of linker types that have been used to couple cytotoxic agents to antibodies include, but are not limited to, hydrazones, thioethers, esters, disulfides, and peptide-containing linkers. Linkers may be selected that are susceptible to cleavage at low pH within the lysosomal compartment or to cleavage by proteases such as cathepsins, such as cathepsins B, C, D, which are preferentially expressed in tumor tissue.

chimeric antigen receptor

The antibodies of the invention or antigen-binding fragments thereof can be used to construct chimeric antigen receptors (CARs) that possess the ability to direct T-cell specificity and reactivity toward CD24-expressing cells (e.g., tumor cells) in a non-MHC-restricted manner. .

In a seventh aspect, the invention provides a chimeric antigen receptor (CAR) comprising the antigen-binding domain of an antibody of the invention or an antigen-binding fragment thereof.

In certain embodiments, the antigen-binding domain comprises the heavy chain variable region and the light chain variable region of an antibody of the invention or an antigen-binding fragment thereof.

In certain embodiments, the antigen binding domain is a scFv.

In certain embodiments, the chimeric antigen receptor comprises an antigen-binding fragment (eg, scFv) of an antibody of the invention.

In certain embodiments, the chimeric antigen receptor is expressed by immune effector cells (eg, T cells).

In certain embodiments, the chimeric antigen receptor further includes a transmembrane domain, one or more intracellular T cell signaling domains (e.g., T cell receptor signaling domain, T cell costimulatory signaling domain, or its combination). The T cell receptor signaling domain refers to the portion of the CAR that contains the intracellular domain of the T cell receptor (eg, the intracellular portion of the CD3ζ protein). The costimulatory signaling domain refers to the part of the intracellular domain of the CAR that contains costimulatory molecules, which are cell surface molecules other than antigen receptors or their ligands required for efficient lymphocyte response to antigens. .

In certain embodiments, a spacer domain comprising a polypeptide sequence may be present between the antigen-binding domain and the transmembrane domain of the CAR. The spacer domain may comprise up to 300 amino acids, preferably 10 to 100 amino acids, and most preferably 25 to 50 amino acids. In some embodiments, the spacer domain may comprise an immunoglobulin domain, such as a human immunoglobulin sequence. In certain exemplary embodiments, the immunoglobulin domain comprises immunoglobulin CH2 and CH3 domain sequences. In such embodiments, without being bound by a particular theory, it is believed that the CH2 and CH3 domains extend the antigen-binding domain of the CAR away from the membrane of the CAR-expressing cell and more accurately mimic the size and Domain structure.

In certain embodiments, the transmembrane domain can be derived from natural or synthetic sources. In such implementations , the domain may be derived from any membrane-bound or transmembrane protein. Exemplary transmembrane domains that can be used in the CAR of the invention can include at least the transmembrane region of the alpha, beta or zeta chain of a T cell receptor, which can be selected from the group consisting of CD28, CD3ε, CD45, CD4, CD5, CDS, CD9, CD16, CD22, CD33, CD37, CD64, CD80, CD86, CD134, CD137, CD154. Alternatively, the transmembrane domain may be synthetic, in which case it will contain predominantly hydrophobic residues such as leucine and valine. In certain exemplary embodiments, the transmembrane domain comprises a transmembrane domain of a T cell receptor, such as a CD8 transmembrane domain. In certain exemplary embodiments, the transmembrane domain comprises the transmembrane domain of a T cell costimulatory molecule (eg, CD137 or CD28).

In certain embodiments, examples of intracellular T cell domains useful for use in the CAR include cytoplasmic sequences and costimulatory molecules of the T cell receptor (TCR) The cytoplasmic sequences and costimulatory molecules cooperate to initiate signal transduction upon antigen receptor engagement, as well as any derivatives or variants of these sequences and any synthetic sequences having the same functional capabilities.

In certain embodiments, the intracellular region of the CAR may comprise a primary cytoplasmic signaling sequence that acts in a stimulatory manner, which may comprise a signal termed an immunoreceptor tyrosine-based activation motif or ITAM Motif. Examples of ITAMs containing primary cytoplasmic signal sequences that may be included in the CAR include those from CD3ζ, FcRγ, FcRβ, CD3γ, CD3δ, CD3ε, CDS, CD22, CD79a, CD79b, and CD66d proteins.

In certain embodiments, the intracellular region of the CAR may comprise an ITAM containing a primary cytoplasmic signaling domain (eg, CD3ζ) by itself or in combination with any other desired cytoplasmic domain that may be used in the context of a CAR. For example, the cytoplasmic domain of the CAR includes a CD3ζ chain portion and an intracellular costimulatory signaling domain. The costimulatory signaling domain refers to the portion of the CAR that contains the intracellular domain of costimulatory molecules. Costimulatory molecules are cell surface molecules other than the antigen receptor or its ligand required for efficient lymphocyte response to antigen. Examples of such molecules include CD27, CD28, 4-1BB (CD137), OX40 (CD134), CD30, CD40, PD-1, ICOS, Lymphocyte Function Associated Antigen 1 (LFA-1), CD2, CD7, LIGHT, NKG2C and B7-H3.

In certain embodiments, the CAR can comprise a CD3ζ signaling domain, a CD8 signaling domain, a CD28 signaling domain, a CD137 signaling domain, or any combination thereof. The order of the one or more T cell signaling domains on the CAR can be changed as needed by those skilled in the art.

Methods of generating chimeric antigen receptors, T cells comprising such receptors, and their uses (e.g., for treating cancer) are known in the art. For example, chimeric antigen-binding receptors encoding the invention can be The nucleic acid molecule is included in an expression vector (eg, a lentiviral vector) for expression in a host cell, such as a T cell, to produce the CAR. In certain exemplary embodiments, methods of using the chimeric antigen receptor include isolating T cells from a subject, using an encoding Transforming T cells with an expression vector (eg, a lentiviral vector) for a chimeric antigen receptor, and administering the engineered T cells expressing the chimeric antigen receptor to the subject for treatment, e.g., for treating a disease tumors in the subjects.

In an eighth aspect, the invention provides an isolated nucleic acid molecule comprising a nucleotide sequence encoding a chimeric antigen receptor of the invention. In certain embodiments, the isolated nucleic acid molecule encodes a chimeric antigen receptor of the invention.

In a ninth aspect, the invention provides a vector (eg a cloning vector or an expression vector) comprising an isolated nucleic acid molecule as described above. In certain embodiments, vectors of the invention are, for example, plasmids.

In a tenth aspect, the invention provides a host cell expressing a chimeric antigen receptor of the invention and/or comprising an isolated nucleic acid molecule or vector as described above. In certain embodiments, the host cells are immune effector cells (eg, T cells and/or NK cells). In certain embodiments, the host cell is a chimeric antigen receptor T cell (CAR-T).

pharmaceutical composition

In an eleventh aspect, the present invention provides a pharmaceutical composition, which contains the antibody or antigen-binding fragment thereof described in the first aspect of the present invention, the isolated nucleic acid molecule described in the second aspect, the third aspect Vector, the host cell described in the fourth aspect, the bispecific or multispecific molecule described in the fifth aspect, the immunoconjugate described in the sixth aspect, the chimeric antigen receptor described in the seventh aspect, the The isolated nucleic acid molecule described in the eighth aspect, the vector described in the ninth aspect, or the host cell described in the tenth aspect, and pharmaceutically acceptable carriers and/or excipients.

In certain embodiments, pharmaceutical compositions of the invention comprise an antibody of the invention or an antigen-binding fragment thereof.

In certain embodiments, pharmaceutical compositions of the invention comprise bispecific or multispecific molecules of the invention.

In certain embodiments, pharmaceutical compositions of the invention comprise immunoconjugates of the invention.

In certain embodiments, the pharmaceutical composition of the present invention includes the immunoconjugate described in the sixth aspect, the chimeric antigen receptor described in the seventh aspect, the isolated nucleic acid molecule described in the eighth aspect, the ninth aspect The vector described in the aspect or the host cell described in the tenth aspect.

In certain embodiments, the pharmaceutical compositions may also include additional pharmaceutically active agents.

In certain embodiments, the additional pharmaceutically active agent is a drug with anti-tumor activity, such as an alkylating agent, a mitosis inhibitor, an anti-tumor antibiotic, an antimetabolite, a topoisomerase inhibitor, a tyrosine kinase Inhibitors, radionuclide agents, radiosensitizers, anti-angiogenic agents, cytokines, specific targeting tumor cell antibodies, immune checkpoint inhibitors, etc.

In certain embodiments, the additional pharmaceutically active agent is an immune checkpoint inhibitor.

In certain embodiments, the additional pharmaceutically active agent is an anti-PD-1 antibody or an anti-PD-L1 antibody.

In certain embodiments, in the pharmaceutical composition, an antibody of the invention or an antigen-binding fragment thereof, a bispecific or multispecific molecule, an immunoconjugate, a chimeric antigen receptor, an isolated nucleic acid molecule, The vector or host cell and the additional pharmaceutically active agent may be provided as separate components or as mixed components. Accordingly, the antibodies or antigen-binding fragments thereof, bispecific or multispecific molecules, immunoconjugates, chimeric antigen receptors, isolated nucleic acid molecules, vectors or host cells of the invention may be combined with said additional pharmaceutically active agent. Administer simultaneously, separately or sequentially.

The antibodies or antigen-binding fragments thereof, bispecific or multispecific molecules, immunoconjugates, chimeric antigen receptors, isolated nucleic acid molecules, vectors or host cells of the invention or the pharmaceutical compositions of the invention can be formulated into medicines Any dosage form known in the art, for example, tablets, pills, suspensions, emulsions, solutions, gels, capsules, powders, granules, elixirs, lozenges, suppositories, injections (including injections, injections Sterile powders and concentrated solutions for injection), inhalants, sprays, etc. The preferred dosage form depends on the intended mode of administration and therapeutic use. The pharmaceutical compositions of the present invention should be sterile and stable under the conditions of production and storage. One preferred dosage form is an injection. Such injections may be sterile injectable solutions. For example, sterile injectable solutions may be prepared by incorporating in an appropriate solvent the requisite dose of an antibody of the invention, or antigen-binding fragment thereof, and, optionally, other desired ingredients including, but not (limited to, pH adjuster, surfactant, adjuvant, ionic strength enhancer, isotonic agent, preservative, diluent, or any combination thereof), followed by filter sterilization. Additionally, sterile injectable solutions may be prepared as sterile lyophilized powders (for example, by vacuum drying or freeze drying) for ease of storage and use. Such sterile lyophilized powder can be dispersed in a suitable carrier before use, such as water for injection (WFI), bacteriostatic water for injection (BWFI), sodium chloride solution (such as 0.9% (w/v) NaCl), Glucose solutions (eg 5% glucose), surfactant containing solutions (eg 0.01% polysorbate 20), pH buffer solutions (eg phosphate buffer solution), Ringer's solution and any combination thereof.

Accordingly, in certain exemplary embodiments, pharmaceutical compositions of the invention comprise sterile injectable liquids (such as aqueous or non-aqueous suspensions or solutions). In certain exemplary embodiments, such sterile injectable liquid is selected from water for injection (WFI), bacteriostatic water for injection (BWFI), sodium chloride solution (e.g., 0.9% (w/v) NaCl), dextrose solutions (eg 5% glucose), surfactant containing solutions (eg 0.01% polysorbate 20), pH buffer solutions (eg phosphate buffer solution), Ringer's solution and any combination thereof.

The antibodies of the present invention or antigen-binding fragments thereof, bispecific or multispecific molecules, immunoconjugates, chimeric antigen receptors, isolated nucleic acid molecules, vectors or host cells or pharmaceutical compositions of the present invention can be obtained by any known Any suitable method of administration, including, but not limited to, oral, buccal, sublingual, intraocular, topical, parenteral, rectal, intrathecal, intracytoplasmic reticulum, inguinal, intravesical, topical (e.g., powder, ointment or drops), or the nasal route. However, for many therapeutic uses, the preferred route/mode of administration is parenteral (eg intravenous or bolus injection, subcutaneous injection, intraperitoneal injection, intramuscular injection). The skilled artisan will understand that the route and/or mode of administration will vary depending on the intended purpose. In certain embodiments, the antibodies or antigen-binding fragments thereof, bispecific or multispecific molecules, immunoconjugates, chimeric antigen receptors, isolated nucleic acid molecules, vectors or host cells of the invention or The pharmaceutical composition is administered by intravenous injection or bolus injection.

The pharmaceutical composition of the present invention may include a "therapeutic effective amount" or a "preventive effective amount" of the antibody or antigen-binding fragment thereof described in the first aspect of the present invention, the isolated nucleic acid molecule described in the second aspect, or the third aspect of the invention. The vector described in the fourth aspect, the host cell described in the fourth aspect, the bispecific or multispecific molecule described in the fifth aspect, the immunoconjugate described in the sixth aspect, the chimeric antigen receptor described in the seventh aspect , the isolated nucleic acid molecule described in the eighth aspect, the vector described in the ninth aspect, or the host cell described in the tenth aspect. "Prophylactically effective amount" refers to an amount sufficient to prevent, prevent, or delay the occurrence of disease. A "therapeutically effective amount" means an amount sufficient to cure or at least partially prevent disease and its complications in a patient who is already suffering from the disease. The therapeutically effective amount may vary depending on factors such as the severity of the disease to be treated, the overall state of the patient's own immune system, the patient's general condition such as age, weight and gender, the manner in which the drug is administered, and other concurrent treatments administered. wait.

Therapeutic applications

The antibody of the present invention specifically binds to human CD24 and can block the binding of CD24 to its ligand (such as Siglec-10), thereby releasing the immunosuppressive signaling pathway mediated by SHP-1/SHP-2 and inducing macrophages to respond to Phagocytosis of tumor cells, thereby providing the following therapeutic applications.

In one aspect, the invention provides a method for enhancing an immune response or preventing and/or treating tumors in a subject (e.g., a human), the method comprising administering to the subject an effective amount selected from The following reagents: the antibody or antigen-binding fragment thereof described in the first aspect, the isolated nucleic acid molecule described in the second aspect, the vector described in the third aspect, the host cell described in the fourth aspect, the fifth aspect The bispecific or multispecific molecule, the immunoconjugate described in the sixth aspect, the chimeric antigen receptor described in the seventh aspect, the isolated nucleic acid molecule described in the eighth aspect, the ninth aspect The vector, or the host cell described in the tenth aspect, or the pharmaceutical composition described in the eleventh aspect. The present invention also relates to the use of each of the above-mentioned agents in the preparation of medicaments for enhancing immune responses or preventing and/or treating tumors in a subject (eg, a human).

In certain embodiments, the immune response includes a macrophage-mediated immune response.

In certain embodiments, the tumor expression involves CD24-positive tumor cells, and/or, involves CD24 ligand (eg, Siglec-10)-positive macrophages.

In certain embodiments, the tumor can be of any tumor type that expresses CD24, including various hematological tumors as well as solid tumors. In certain embodiments, the tumor is a solid tumor, such as breast cancer (e.g., triple negative breast cancer), ovarian cancer, liver cancer, lung cancer, colorectal cancer, gastric cancer, pancreatic cancer, bladder cancer, prostate cancer, renal cell carcinoma Cancer, cervical cancer, endometrial cancer, cholangiocarcinoma, kidney cancer, nasopharyngeal cancer, thyroid cancer, brain cancer, testicular cancer, bone cancer, lymphoma or glioma, etc. In certain embodiments, the tumor is a hematological neoplasm, eg, leukemia, lymphoma, myeloma.

Ovarian Cancer (OC) is a common gynecological malignant tumor. It is a highly heterogeneous epithelial tumor with different histological subtypes and genetic and biological characteristics, including serous carcinoma, endometrioid carcinoma, hyaline carcinoma, Cellular and mucinous carcinomas. There are 310,000 new cases of ovarian cancer and more than 200,000 deaths worldwide every year (Hyuna S, et al: Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries.CA CANCER J CLIN 2021; 0:1 –41.). 75% of ovarian cancers are serous cancers, with a five-year survival rate of 35%. They are an extremely malignant type of cancer and are usually diagnosed at an advanced stage.

Breast cancer is the most common cancer among women each year and has a high mortality rate (approximately 50%). Currently, breast cancer is divided into 4 molecular subtypes. Positive expression of ER/PR and/or HER2 determines ER-positive and/or HER2-positive subtypes, while loss of ER, PR, and HER2 expression defines triple-negative breast cancer ( TNBC). In contrast, TNBC lacks targeted therapies and is still treated with systemic chemotherapy drugs. In addition, TNBC tends to exhibit more aggressive clinical features and tends to relapse earlier and more frequently, making it the most aggressive breast cancer subtype (Plasilova ML, et al: Features of triple-negative breast cancer :Analysis of 38,813 cases from the National Cancer Database. Medicine (Baltimore) 2016;95:e4614.).

Dr. Weissman's team found that CD24 is a signaling protein expressed by ovarian cancer and breast cancer cells that inhibits macrophage immune phagocytosis. Ovarian cancer and triple-negative breast cancer are greatly affected by CD24 signaling blockade (Amira A. Barkal, et al :Weissman CD24 signaling through macrophage Siglec-10 is a target for cancer. Immunotherapy 2019;572:392-399.). CD24 is overexpressed far more than CD47 and PD-L1 in the above two tumor samples; the CD24 antibody has a stronger effect on sensitizing macrophage phagocytosis in the two tumor cell lines than the CD47 antibody; CD24 gene knockout or CD24 antibody in small It can effectively inhibit tumor growth in mouse tumor models. The above relevant data reflect the immune activation effect of CD24 as a target in ovarian cancer and triple-negative breast cancer. The development of anti-CD24 antibody drugs The research and development is expected to provide effective clinical drugs in the treatment of solid tumors including ovarian cancer and triple-negative breast cancer.

Thus, in certain embodiments, the tumor is preferably ovarian or breast cancer (eg, triple negative breast cancer).

In certain embodiments, the method further includes administering a second therapeutic agent (e.g., a drug with anti-tumor activity) or a second treatment (e.g., surgery, chemotherapy, radiation therapy, targeted therapy, immunotherapy, hormonal therapy , gene therapy or palliative care).

In certain embodiments, the second therapeutic agent is an immune checkpoint inhibitor.

In certain embodiments, the second therapeutic agent is an anti-PD-1 antibody or an anti-PD-L1 antibody.

In one aspect, the invention provides a method for killing or depleting CD24-positive cells in a subject (e.g., a human), the method comprising administering to the subject an effective amount of an agent selected from: : The antibody or antigen-binding fragment thereof according to the first aspect, the isolated nucleic acid molecule according to the second aspect, the vector according to the third aspect, the host cell according to the fourth aspect, the bispecific protein according to the fifth aspect. A specific or multispecific molecule, the immunoconjugate of the sixth aspect, the chimeric antigen receptor of the seventh aspect, the isolated nucleic acid molecule of the eighth aspect, the vector of the ninth aspect, or The host cell according to the tenth aspect, or the pharmaceutical composition according to the eleventh aspect. The present invention also relates to the use of each of the above-mentioned reagents in the preparation of medicaments for killing or depleting CD24-positive cells in a subject (eg, a human).

In certain embodiments, the CD24-positive cells are tumor cells. Therefore, the method can be used for tumor treatment.

In certain embodiments, an agent provided by the invention selected from the following is administered in combination with a second therapeutic agent or therapy: the antibody or antigen-binding fragment thereof described in the first aspect, the isolated antibody described in the second aspect Nucleic acid molecules, vectors according to the third aspect, host cells according to the fourth aspect, bispecific or multispecific molecules according to the fifth aspect, immunoconjugates according to the sixth aspect, immunoconjugates according to the seventh aspect The chimeric antigen receptor described in the eighth aspect, the isolated nucleic acid molecule described in the eighth aspect, the vector described in the ninth aspect, or the host cell described in the tenth aspect, or the pharmaceutical composition described in the eleventh aspect. The second therapeutic agent or treatment may be administered before, simultaneously with, or after the administration of the above-described agent of the invention.

In certain embodiments, the second therapeutic agent is selected from drugs with anti-tumor activity, such as alkylating agents, mitotic inhibitors, anti-tumor antibiotics, antimetabolites, topoisomerase inhibitors, tyrosine kinases Inhibitors, radionuclide agents, radiosensitizers, anti-angiogenic agents, cytokines, molecularly targeted drugs, immune checkpoint inhibitors or oncolytic viruses.

In certain embodiments, the second treatment may be any therapy known for tumors, such as surgery, chemotherapy, radiation therapy, targeted therapy, immunotherapy, hormone therapy, gene therapy, or palliative care.

Detection application

The antibody or antigen-binding fragment thereof of the present invention can specifically bind to CD24 and thus can be used to detect the presence or level of CD24 in a sample.

Accordingly, in another aspect, the invention provides a kit comprising an antibody of the invention or an antigen-binding fragment thereof.

In certain embodiments, the antibodies of the invention, or antigen-binding fragments thereof, are detectably labeled.

In certain embodiments, the kit further includes a second antibody that specifically recognizes an antibody of the invention or an antigen-binding fragment thereof. Preferably, the second antibody further includes a detectable label.

In the present invention, the detectable label may be any substance detectable by fluorescent, spectroscopic, photochemical, biochemical, immunological, electrical, optical or chemical means. It is particularly preferred that such labels can be adapted to immunological detection (eg, enzyme-linked immunoassay, radioimmunoassay, fluorescent immunoassay, chemiluminescence immunoassay, etc.).

In another aspect, the invention provides a method for detecting the presence or amount of CD24 in a sample, comprising the following steps:

(1) Contact the sample with the antibody or antigen-binding fragment thereof of the present invention;

(2) Detect the formation of a complex between the antibody or its antigen-binding fragment and CD24 or detect the amount of the complex.

The formation of the complex indicates the presence of CD24 or CD24-expressing cells.

In certain embodiments, the antibodies of the invention, or antigen-binding fragments thereof, further bear a detectable label. In certain embodiments, in step (2), an antibody or antigen-binding fragment thereof of the invention is detected using a detectably labeled reagent.

The method may be used for diagnostic purposes, or for non-diagnostic purposes (eg, the sample is a cell sample rather than a sample from a patient). In certain embodiments, the CD24 is human CD24.

In certain embodiments, the methods are used to diagnose whether a subject has a tumor that expresses CD24 or to detect whether a tumor is treatable by anti-tumor therapy targeting CD24. In such embodiments, the method may further include: The step of comparing the amount of CD24 in the sample from the subject to a reference value.

The reference value refers to the level of CD24 in a sample from a subject known not to have a tumor that expresses CD24 (also referred to as a "negative reference value"), or to the level of CD24 in a sample from a subject known to have a tumor that expresses CD24. The level in the subject's sample (also called the "positive reference value"). For example, if the amount of CD24 in a sample from the subject is similar to (or not significantly different from) a negative reference value, it indicates that the subject does not have a CD24-expressing tumor, and if the CD24 An increase in the amount in a sample from the subject relative to a negative reference value is an indication that the subject has a CD24-expressing tumor. Furthermore, if the amount of CD24 in a sample from the subject is similar to (or not significantly different from) a positive reference value, this indicates that the subject has a CD24-expressing tumor.

In certain embodiments, the sample may be selected from urine, blood, serum, plasma, saliva, ascites fluid, circulating cells, circulating tumor cells, non-tissue associated cells (i.e., free cells), tissue (e.g., surgically resected tumor tissue, biopsy or fine needle aspiration tissue), histological preparations, etc.

In certain embodiments, the methods further comprise administering a CD24-targeted immunotherapy to a subject diagnosed with a CD24-expressing tumor.

In another aspect, the use of the antibody or antigen-binding fragment or kit thereof of the present invention in preparing a detection reagent is provided, and the detection reagent is used to determine the presence or amount of CD24 in a sample, and to diagnose whether a subject is suffering from the disease. Have a tumor that expresses CD24, and/or test whether the tumor can be treated with an anti-tumor therapy that targets CD24.

Definition of Terms

In the present invention, unless otherwise stated, scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Moreover, the cell culture, molecular biology, biochemistry, nucleic acid chemistry, immunology and other operating procedures used in this article are routine procedures widely used in the corresponding fields. Meanwhile, in order to better understand the present invention, definitions and explanations of relevant terms are provided below.

As used herein, the term "antibody" in its broadest sense refers to molecules that specifically bind to an antigenic determinant and may include a variety of antibody structures so long as they exhibit the desired antigen-binding activity. Typically, resist A body may be an immunoglobulin molecule composed of two pairs of polypeptide chains, each pair having a light chain (LC) and a heavy chain (HC). Antibody light chains can be classified into kappa (kappa) and lambda (lambda) light chains. Heavy chains can be classified as mu, delta, gamma, alpha, or epsilon, and define the antibody's isotype as IgM, IgD, IgG, IgA, and IgE, respectively. Within the light and heavy chains, the variable and constant regions are connected by a "J" region of approximately 12 or more amino acids, and the heavy chain also contains a "D" region of approximately 3 or more amino acids. Each heavy chain consists of a heavy chain variable region (VH) and a heavy chain constant region (CH). The heavy chain constant region consists of 3 domains (CH1, CH2 and CH3). Each light chain consists of a light chain variable region (VL) and a light chain constant region (CL). The light chain constant region consists of one domain, CL. The constant domain is not directly involved in the binding of antibodies to antigens, but exhibits a variety of effector functions, such as mediating the interaction of immunoglobulins with host tissues or factors, including various cells of the immune system (e.g., effector cells) and classical complement. Binding of the first component of the system (C1q). The VH and VL regions can also be subdivided into regions of high variability called complementarity determining regions (CDRs), interspersed with more conservative regions called framework regions (FRs). Each _VH and _VL consists of 3 CDRs and 4 FRs arranged from the amino terminus to the carboxyl terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The variable regions (VH and VL) of each heavy chain/light chain pair respectively form the antigen-binding site. The assignment of amino acids to each region or domain can follow Kabat, Sequences of Proteins of Immunological Interest (National Institutes of Health, Bethesda, Md. (1987 and 1991)), or Chothia & Lesk (1987) J. Mol. Biol. 196:901- 917; Definition of Chothia et al. (1989) Nature 342:878-883.

As used herein, the term "complementarity determining region" or "CDR" refers to the amino acid residues in the variable region of an antibody that are responsible for antigen binding. The variable regions of the heavy chain and light chain each contain three CDRs, named CDR1, CDR2 and CDR3. The precise boundaries of these CDRs can be defined according to various numbering systems known in the art, such as the Kabat numbering system (Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md., 1991), Chothia numbering system (Chothia & Lesk (1987) J. Mol. Biol. 196:901-917; Chothia et al. (1989) Nature 342:878-883) or IMGT numbering system (Lefranc et al. , Dev. Comparat. Immunol. 27:55-77, 2003). For a given antibody, one skilled in the art will readily identify the CDRs defined by each numbering system. Moreover, the correspondence between different numbering systems is well known to those skilled in the art (for example, see Lefranc et al., Dev. Comparat. Immunol. 27:55-77, 2003).

In the present invention, the CDRs contained in the antibody or antigen-binding fragment thereof of the present invention can be determined according to various numbering systems known in the art. In certain embodiments, the antibodies of the invention or antigen-binding fragments thereof contain CDRs preferably Site selection is determined by the Kabat, Chothia or IMGT numbering system. In certain embodiments, the CDRs contained in the antibodies of the invention, or antigen-binding fragments thereof, are preferably determined by the Kabat numbering system.

As used herein, the term "framework region" or "FR" residues refers to those amino acid residues in an antibody variable region other than the CDR residues as defined above.

The term "antibody" is not limited to any particular method of producing the antibody. This includes, for example, recombinant antibodies, monoclonal antibodies, and polyclonal antibodies. The antibodies may be of different isotypes, for example, IgG (eg, IgG1, IgG2, IgG3 or IgG4 subtypes), IgA1, IgA2, IgD, IgE or IgM antibodies.

As used herein, the term "antigen-binding fragment" of an antibody refers to a polypeptide comprising a fragment of a full-length antibody that retains the ability to specifically bind to the same antigen that the full-length antibody binds, and/or competes with the full-length antibody Specific binding to an antigen, which is also called an "antigen-binding moiety." See generally, Fundamental Immunology, Ch. 7 (Paul, W., ed., 2nd ed., Raven Press, NY (1989)), which is incorporated herein by reference in its entirety for all purposes. It can be obtained by recombinant DNA technology or by enzymatic or chemical cleavage of intact antibodies to produce antigen-binding fragments of the antibody. Non-limiting examples of antigen-binding fragments include Fab, Fab', (Fab') ₂ , Fv, disulfide-linked Fv, scFv, di- scFv, (scFv) ₂ , and polypeptides containing at least a portion of an antibody sufficient to confer specific antigen-binding ability to the polypeptide.

As used herein, the term "Fd" means an antibody fragment consisting of VH and CH1 domains; the term "dAb fragment" means an antibody fragment consisting of a VH domain (Ward et al., Nature 341:544 546 ( 1989)); the term "Fab fragment" means an antibody fragment consisting of VL, VH, CL and CH1 domains; the term "F(ab') ₂ fragment" means an antibody fragment consisting of two fragments connected by a disulfide bridge on the hinge region An antibody fragment of a Fab fragment; the term "Fab'fragment" means the fragment obtained by reducing the disulfide bond connecting the two heavy chain fragments in the F(ab') ₂ fragment, consisting of a complete light chain and the Fd of the heavy chain. Fragment (consisting of VH and CH1 domains).

As used herein, the term "Fv" means an antibody fragment consisting of the VL and VH domains of a single arm of an antibody. Fv fragments are generally considered to be the smallest antibody fragments that can form a complete antigen-binding site. It is generally believed that six CDRs confer the antigen-binding specificity of an antibody. However, even a variable region (such as an Fd fragment, which contains only three CDRs specific for the antigen) can recognize and bind the antigen, although its affinity may be lower than that of the intact binding site.

As used herein, the term "Fc" means a region formed by disulfide bonding of the second and third constant regions of the first heavy chain of an antibody to the second and third constant regions of the second heavy chain. Antibody fragments. The Fc fragment of an antibody has many different functions but does not participate in antigen binding.

As used herein, the term "scFv" refers to a single polypeptide chain comprising VL and VH domains connected by a linker (see, e.g., Bird et al., Science 242:423 -426 (1988); Huston et al., Proc. Natl. Acad. Sci. USA 85:5879-5883 (1988); and Pluckthun, The Pharmacology of Monoclonal Antibodies, Vol. 113, Roseburg and Moore, eds., Springer-Verlag, New York, pp. 269-315 (1994)). Such scFv molecules may have the general structure: _NH2 -VL-linker-VH-COOH or _NH2 -VH-linker-VL-COOH. Suitable prior art linkers consist of repeated GGGGS amino acid sequences or variants thereof. For example, a linker having the amino acid sequence (GGGGS) ₄ can be used, but variants thereof can also be used (Holliger et al. (1993), Proc. Natl. Acad. Sci. USA 90:6444-6448). Other linkers useful in the present invention are provided by Alfthan et al. (1995), Protein Eng. 8:725-731, Choi et al. (2001), Eur. J. Immunol. 31:94-106, Hu et al. (1996), Cancer Res. 56:3055-3061, described by Kipriyanov et al. (1999), J. Mol. Biol. 293:41-56 and Roovers et al. (2001), Cancer Immunol. In some cases, a disulfide bond may also exist between VH and VL of scFv. In certain embodiments of the invention, scFv can form di-scFv, which refers to two or more individual scFvs connected in series to form an antibody. In certain embodiments of the invention, scFv can form (scFv) ₂ , which refers to two or more individual scFvs joining in parallel to form an antibody.

As used herein, the term "diabody" means one whose VH and VL domains are expressed on a single polypeptide chain but using a linker that is too short to allow pairing between the two domains of the same chain, This forces the domain to pair with the complementary domain of the other chain and creates two antigen binding sites (see, e.g., Holliger P. et al., Proc. Natl. Acad. Sci. USA 90:6444-6448 (1993), and Poljak R.J. et al., Structure 2:1121-1123 (1994)).

As used herein, the term "single-domain antibody (sdAb)" has the meaning commonly understood by those skilled in the art, which refers to an antibody composed of a single monomeric variable domain (e.g., a single heavy chain variable An antibody fragment consisting of a region) that retains the ability to specifically bind to the same antigen that the full-length antibody binds. Single domain antibodies are also called nanobodies.

Each of the above antibody fragments retains the ability to specifically bind to the same antigen that the full-length antibody binds, and/or competes with the full-length antibody for specific binding to the antigen.

Antigen-binding fragments of an antibody (e.g., the above antibody fragments), and the antigen-binding fragments of the antibodies are screened for specificity in the same manner as for intact antibodies.

As used herein, when the term "antibody" is mentioned, it includes not only intact antibodies but also antigen-binding fragments of the antibodies, unless the context clearly indicates otherwise.

As used herein, the term "chimeric antibody" refers to an antibody in which a portion of the light chain or/and heavy chain is derived from an antibody (which may originate from a specific species or belong to a specific species). a specific antibody class or subclass), and the other part of the light chain or/and heavy chain is derived from another antibody (which may be derived from the same or different species or belong to the same or different antibody class or subclass), but regardless of However, it still retains binding activity to the target antigen. In certain embodiments, the term "chimeric antibody" may include antibodies (e.g., human-mouse chimeric antibodies) in which the heavy and light chain variable regions of the antibody are derived from a first antibody (e.g., a murine antibody), and The heavy and light chain constant regions of the antibody are derived from a secondary antibody (eg, a human antibody).

As used herein, the term "humanized antibody" refers to a non-human antibody that has been genetically engineered and whose amino acid sequence has been modified to increase sequence homology to that of a human antibody. Generally speaking, all or part of the CDR region of a humanized antibody comes from a non-human antibody (donor antibody), and all or part of the non-CDR region (for example, variable region FR and/or constant region) comes from a human source. Immunoglobulins (receptor antibodies). Humanized antibodies generally retain the expected properties of the donor antibody, including but not limited to, antigen specificity, affinity, reactivity, etc. The donor antibody can be a mouse, rat, rabbit, or non-human primate (eg, cynomolgus monkey) antibody with desired properties (eg, antigen specificity, affinity, reactivity, etc.).

As used herein, the term "germline antibody gene" or "germline antibody gene segment" refers to an immunoglobulin-encoding sequence present in the genome of an organism , which have not undergone the maturation process that leads to genetic rearrangements and mutations that lead to the expression of specific immunoglobulins. In the present invention, the expression "heavy chain germline gene" refers to the germline antibody gene or gene fragment encoding the immunoglobulin heavy chain, which includes V gene (variable), D gene (diversity), and J gene (joining). and C gene (constant); similarly, the expression "light chain germline gene" refers to the germline antibody gene or gene fragment encoding the immunoglobulin light chain, which includes V gene (variable), J gene (joining) and C gene (constant). In the present invention, the amino acid sequence encoded by the germline antibody gene or germline antibody gene fragment is also called a "germline sequence". Germline antibody genes or germline antibody gene fragments and their corresponding germline sequences are well known to those skilled in the art and can be obtained or queried from professional databases (eg, IMGT, UNSWIg, NCBI or VBASE2).

As used herein, the term "specific binding" refers to a non-random binding reaction between two molecules, such as the reaction between an antibody and the antigen against which it is directed. The strength or affinity of a specific binding interaction can be expressed by the equilibrium dissociation constant (K _D ) of the interaction. In the present invention, the term " _KD " refers to the dissociation equilibrium constant of a specific antibody-antigen interaction, which is used to describe the binding affinity between an antibody and an antigen. The smaller the equilibrium dissociation constant, the tighter the antibody-antigen binding, and the higher the affinity between the antibody and the antigen.

The specific binding properties between two molecules can be determined using methods known in the art. One approach involves measuring the rate at which antigen binding site/antigen complexes form and dissociate. Both the "association rate constant" (ka or kon) and the "dissociation rate constant" (kdis or koff) can be calculated from the concentration and the actual rates of association and dissociation (see Malmqvist M, Nature, 1993, 361 :186-187). The ratio kdis/kon is equal to the dissociation constant _KD (see Davies et al., Annual Rev Biochem, 1990; 59:439-473). K _D , kon and kdis values can be measured by any valid method. In certain embodiments, dissociation constants can be measured in Biacore using surface plasmon resonance (SPR). Alternatively, bioluminescence interferometry or Kinexa can be used to measure dissociation constants.

As used herein, the term "chimeric antigen receptor (CAR)" refers to a recombinant polypeptide construct comprising at least one extracellular antigen-binding domain, spacer domain, transmembrane domain, and intracellular signaling domain , which combines antibody-based specificity for an antigen of interest (eg, CD24) with an immune effector cell-activating intracellular domain to exhibit specific immune activity against cells expressing the antigen of interest (eg, CD24). In the present invention, the expression "CAR-expressing cell" refers to a cell that expresses a CAR and has an antigen specificity determined by the targeting domain of the CAR.

As used herein, the term "immune effector cell" refers to any cell of the immune system having one or more effector functions (e.g., cytotoxic cell killing activity, secretion of cytokines, induction of ADCC and/or CDC) . Typically, immune effector cells are cells that are of hematopoietic origin and play a role in immune responses. The term "effector function" refers to a specialized function of an immune effector cell, such as a function or response that enhances or promotes an immune attack on a target cell (eg, kills the target cell, or inhibits its growth or proliferation). The effector function of a T cell may, for example, be cytolytic activity or auxiliary or activity including secretion of cytokines. Examples of immune effector cells include T cells (eg, alpha/beta T cells and gamma/delta T cells), B cells, natural killer (NK) cells, natural killer T (NKT) cells, mast cells, and bone marrow-derived macrophages.

As used herein, the term "cytotoxic agent" includes any agent that is harmful to cells (eg, kills cells), such as chemotherapeutic drugs, bacterial toxins, phytotoxins, or radioactive isotopes, and the like.

As used herein, the term "vector" refers to a nucleic acid delivery vehicle into which a polynucleotide can be inserted. When the vector can express the protein encoded by the inserted polynucleotide, the vector is called an expression vector. The vector can be introduced into the host cell through transformation, transduction or transfection, so that the genetic material elements it carries can be expressed in the host cell. Vectors are well known to those skilled in the art, including but not limited to: plasmids; phagemids; cosmids; artificial chromosomes, such as yeast artificial chromosomes (YAC), bacterial artificial chromosomes (BAC) or P1-derived artificial chromosomes (PAC) ; Phages such as lambda phage or M13 phage and animal viruses, etc. Animal viruses that can be used as vectors include, but are not limited to, retroviruses (including lentiviruses), adenoviruses, adeno-associated viruses, herpesviruses (such as herpes simplex virus), poxviruses, baculoviruses, papillomaviruses, papillomaviruses, Polyomavacuolating viruses (such as SV40). A vector can contain a variety of expression-controlling elements, including, but not limited to, promoter sequences, transcription initiation sequences, enhancer sequences, selection elements, and reporter genes. In addition, the vector may also contain an origin of replication site.

As used herein, the term "host cell" refers to a cell that can be used to introduce a vector, which includes, but is not limited to, prokaryotic cells such as E. coli or Bacillus subtilis, fungal cells such as yeast cells or Aspergillus, etc. Insect cells such as S2 Drosophila cells or Sf9, or animal cells such as fibroblasts, CHO cells, COS cells, NSO cells, HeLa cells, BHK cells, HEK 293 cells or human cells, immune cells (such as T lymphocytes cells, NK cells, monocytes, macrophages or dendritic cells, etc.). Host cells can include single cells or populations of cells.

As used herein, the term "identity" is used to refer to the match of sequences between two polypeptides or between two nucleic acids. When a position in both sequences being compared is occupied by the same base or amino acid monomer subunit (for example, a position in each of two DNA molecules is occupied by adenine, or two A certain position in each polypeptide is occupied by lysine), then the molecules are identical at that position. "Percent identity" between two sequences is a function of the number of matching positions common to the two sequences divided by the number of positions compared × 100. For example, if 6 out of 10 positions of two sequences match, then the two sequences are 60% identical. For example, the DNA sequences CTGACT and CAGGTT share 50% identity (matching at 3 positions out of a total of 6 positions). Typically, comparisons are made when two sequences are aligned to yield maximum identity. Such alignment can be accomplished using, for example, the method of Needleman et al. (1970) J. Mol. Biol. 48:443-453, which can be conveniently performed by a computer program such as the Align program (DNAstar, Inc.). It is also possible to use the PAM120 weight residue table using the algorithm of E. Meyers and W. Miller (Comput. Appl Biosci., 4:11-17 (1988)) integrated into the ALIGN program (version 2.0). , a gap length penalty of 12 and a gap penalty of 4 to determine the percent identity between two amino acid sequences. In addition, it is possible to use the Needleman and Wunsch (J MoI Biol. 48:444-453 (1970)) algorithm in the GAP program of the software package (available at www.gcg.com), using Blossum 62 matrix or PAM250 matrix and 16, 14, 12 , a gap weight of 10, 8, 6 or 4 and a length weight of 1, 2, 3, 4, 5 or 6 to determine the percent identity between two amino acid sequences.

As used herein, the term "conservative substitution" means an amino acid substitution that does not adversely affect or alter the expected properties of the protein/polypeptide comprising the amino acid sequence. For example, conservative substitutions can be introduced by standard techniques known in the art, such as site-directed mutagenesis and PCR-mediated mutagenesis. Conservative amino acid substitutions include those in which an amino acid residue is replaced with an amino acid residue having a similar side chain, e.g., one that is physically or functionally similar to the corresponding amino acid residue (e.g., has similar size, shape, charge, chemical properties, including ability to form covalent bonds or hydrogen bonds, etc.). Families of amino acid residues with similar side chains have been defined in the art. These families include those with basic side chains (e.g., lysine, arginine, and histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine , asparagine, glutamine, serine, threonine, tyrosine, cysteine, tryptophan), non-polar side chains (such as alanine, valine, leucine, isoleucine amino acids, proline, phenylalanine, methionine), β-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, Phenylalanine, tryptophan, histidine) amino acids. Therefore, it is preferred to replace the corresponding amino acid residue with another amino acid residue from the same side chain family. Methods for identifying conservative substitutions of amino acids are well known in the art (see, e.g., Brummell et al., Biochem. 32:1180-1187 (1993); Kobayashi et al., Protein Eng. 12(10):879-884 (1999) ; and Burks et al. Proc. Natl Acad. Set USA 94:412-417 (1997), which is incorporated herein by reference).

The twenty conventional amino acids involved in this article have been prepared following conventional usage. See, e.g., Immunology-A Synthesis (2nd Edition, E.S. Golub and D.R. Gren, Eds., Sinauer Associates, Sunderland, Mass. (1991)), which is incorporated herein by reference. In the present invention, the terms "polypeptide" and "protein" have the same meaning and are used interchangeably. And in the present invention, amino acids are generally represented by one-letter and three-letter abbreviations well known in the art. For example, alanine can be represented by A or Ala.

As used herein, the term "pharmaceutically acceptable carrier and/or excipient" means a carrier and/or excipient that is pharmacologically and/or physiologically compatible with the subject and the active ingredient, They are well known in the art (see, e.g., Remington's Pharmaceutical Sciences. Edited by Gennaro AR, 19th ed. Pennsylvania: Mack Publishing Company, 1995) and include, but are not limited to: pH adjusters, surfactants, adjuvants, ionic strength enhancers Agents, diluents, agents to maintain osmotic pressure, agents to delay absorption, preservatives. For example, pH adjusting agents include, but are not limited to, phosphate buffer. Surfactants include, but are not limited to, cationic, anionic or nonionic surfactants such as Tween-80. Ionic strength enhancers include, but are not limited to, sodium chloride. Preservatives include, but are not limited to, various antibacterial and antifungal agents, such as parabens, chlorobutanol, phenol, sorbic acid, etc. Agents that maintain osmotic pressure include, but are not limited to, sugar, NaCl, and the like. Agents that delay absorption include, but are not limited to, monostearate and gelatin. Diluents include, but are not limited to, water, aqueous buffers (such as buffered saline), alcohols and polyols (such as glycerol), and the like. Preservatives include, but are not limited to, various antibacterial and antifungal agents, such as thimerosal, 2-phenoxyethanol, parabens, chlorobutanol, phenol, sorbic acid, etc. Stabilizers have the meaning commonly understood by those skilled in the art, which can stabilize the desired activity of active ingredients in medicines, including but not limited to sodium glutamate, gelatin, SPGA, sugars (such as sorbitol, mannitol, starch, sucrose) , lactose, dextran, or glucose), amino acids (such as glutamic acid, glycine), proteins (such as dry whey, albumin or casein) or their degradation products (such as lactalbumin hydrolyzate), etc. In certain exemplary embodiments, the pharmaceutically acceptable carrier or excipient includes sterile injectable liquids (such as aqueous or non-aqueous suspensions or solutions). In certain exemplary embodiments, such sterile injectable liquid is selected from water for injection (WFI), bacteriostatic water for injection (BWFI), sodium chloride solution (e.g., 0.9% (w/v) NaCl), dextrose solutions (eg 5% glucose), surfactant containing solutions (eg 0.01% polysorbate 20), pH buffer solutions (eg phosphate buffer solution), Ringer's solution and any combination thereof.

As used herein, the term "prevention" refers to a method performed to prevent or delay the occurrence of a disease or condition or symptom (eg, tumor) in a subject. As used herein, the term "treatment" refers to a method performed to obtain a beneficial or desired clinical result. For the purposes of this invention, beneficial or desired clinical results include, but are not limited to, alleviation of symptoms, reduction of the extent of the disease, stabilization (i.e., no further worsening) of the disease state, delaying or slowing the progression of the disease, ameliorating or alleviating the symptoms of the disease. status, and relief of symptoms (whether partial or complete), whether detectable or undetectable. In addition, "treatment" may also refer to prolonging survival compared to expected survival if not receiving treatment.

As used herein, the term "subject" refers to a mammal, such as a primate mammal, such as a human. In certain embodiments, the subject (eg, human) has a tumor.

beneficial effects

The present invention provides monoclonal antibodies with high affinity for cell surface CD24, which can effectively block the binding of CD24 and its ligand (such as Siglec-10), thereby releasing SHP-1/SHP-2-mediated immunosuppression. signaling pathway, inducing macrophage phagocytosis of tumor cells. Therefore, the antibodies of the present invention have utility in treating CD24-expressing tumors. tumor potential and has significant clinical value.

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, but those skilled in the art will understand that the following drawings and examples are only used to illustrate the present invention and do not limit the scope of the present invention. Various objects and advantageous aspects of the present invention will become apparent to those skilled in the art from the accompanying drawings and the following detailed description of preferred embodiments.

Description of the drawings

Figure 1A shows the flow cytometric evaluation results of measuring the binding activity of mouse antibody 19H11 to MCF7.

Figure 1B shows the flow cytometric evaluation results of measuring the binding activity of mouse antibody 19H11 to Huh.

Figure 2A shows the flow cytometric evaluation results of measuring the binding activity of chimeric antibody ch19H11 to MCF7.

Figure 2B shows the ELISA evaluation results for measuring the binding activity of chimeric antibody ch19H11 to recombinantly expressed CD24.

Figure 2C shows the ELIS evaluation results for measuring the binding activity of chimeric antibody ch19H11 to chemically synthesized CD24 polypeptide.

Figure 3A is a flow cytometric evaluation result of measuring the binding activity of humanized antibody GB7011-05 to Huh7 cells that naturally express human CD24.

Figure 3B is a flow cytometric evaluation result of measuring the binding activity of humanized antibody GB7011-05 to MCF7 cells that naturally express human CD24.

Figure 4 shows the blocking activity of humanized antibody GB7011-05 in blocking the binding of CD24 on the cell membrane surface to its receptor protein Siglec10.

Figure 5A shows the phagocytosis of NALM6 tumor cells by M1 macrophages induced by humanized antibody GB7011-05.

Figure 5B shows the phagocytosis of NALM6 tumor cells by M2 macrophages induced by humanized antibody GB7011-05.

sequence information

Table 1: Information on the sequences covered by this application is described in the table below.

Detailed ways

The invention will now be described with reference to the following examples which are intended to illustrate but not to limit the invention.

Those skilled in the art will appreciate that the examples describe the invention by way of example and are not intended to limit the scope of protection claimed in the application. The experimental methods in the examples are all conventional methods unless otherwise specified. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

Example 1: Generation of mouse anti-human CD24 antibodies

Human CD24 (amino acid sequence such as SEQ ID NO: 13) was overexpressed on HEK293 cells (ATCC) and CHOS cells (Invitrogen) through lentiviral infection (MOI=3-10, 5μg/ml polybrene). The lentivirus was provided by Shanghai Jikai Gene Medical Technology Co., Ltd. After the cells were infected for 72 hours, corresponding antibiotics were added and cultured for 2-4 weeks, amplified and cryopreserved to obtain HEK293-CD24 and CHOS-CD24 cells for subsequent experiments. .

In order to obtain anti-human CD24 antibodies, the constructed CHOS-CD24 cells overexpressing human CD24 were used to immunize Balb/c mice (Beijing Vital River Experimental Animal Technology Co., Ltd., strain code 216); the primary immunization adjuvant was completely free. His adjuvant CFA (InvivoGen Company, product number vac-cfa-60), and subsequent immune adjuvants use IFA (InvivoGen Company, product number vac-ifa-60); the immune route is subcutaneous multiple points. After multiple immunizations, the spleen cells of the immunized mice were fused with mouse myeloma cells SP2/0 using the polyethylene glycol method to obtain B cell fusions that can express antibodies and proliferate indefinitely in vitro, and were selectively cultured in HAT Cultured in the substrate. The fused hybridoma cells were plated in a 96-well cell culture plate, and the antibodies in the supernatant were used to bind CD24 at the cellular level. Naturally expressing human breast cancer tumor cells MCF7, CD24-overexpressing HEK293-CD24, and CD24-negative cells HEK293 According to the situation, the target positive clones (antibodies that bind MCF7 and HEK293-CD24, but do not bind HEK293) are screened out and subjected to 2-3 rounds of subcloning to obtain monoclonal cell lines.

High-throughput screening of mouse anti-binding cell levels: Human CD24-expressing cells and negative control cells (MCF7/HEK293-CD24; HEK293) were plated separately in the screening. Dilute 10,000 cells into 100 μL of complete culture medium, use a flat-bottomed 96-well plate, allow the cells to adhere or sink to the bottom of the well overnight, and remove the supernatant the next day. Add 100 μL of hybridoma supernatant to be screened to the cell plate and incubate at room temperature for 1 hour. After removing the supernatant, add 100 μL of secondary antibody (DyLight488 goat anti-mouse IgG (Abcam catalog number ab97015)) to each well at a concentration of 5 μg/mL, and incubate at room temperature for 0.5 hours. After the staining is completed, remove the supernatant and add 100 μL DPBS to each well, and put it on the machine for reading. A full field cell scanning analyzer (Nexcelom, model Image Cytometer) to read the test plate. During the measurement, the second antibody is selected to correspond to the fluorescence channel and the bright field channel to perform high-speed scanning and imaging of the cells in the well. The imaging obtained by the fluorescence channel counts the antibody-bound cells according to the fluorescently labeled cell morphology and fluorescence intensity setting parameters. The imaging obtained by the brightfield channel counts adherent cells according to the cell morphology setting parameters, and then the two sets of data are compared. In addition, the percentage of cells showing fluorescence that binds to the antibody to the total number of cells is obtained. Based on this ratio, the binding effect of the antibody in the fusion tumor supernatant to CD24-expressing cells was determined. The data of murine antibody 19H11-derived fusion tumor supernatant binding to several cells in high-throughput screening are shown in Table 2.

Table 2: Binding performance of mouse antibodies in high-throughput screening at the cellular level

Flow cytometry evaluation of mouse anti-CD24 binding: Place 500,000 CD24-expressing cells (human breast cancer tumor cells MCF7, human liver tumor cells Huh7) into FACS buffer (PBS+2% FBS)/well, and add the test Mouse-derived antibodies were then incubated at 4°C for 1 hour (ISO was used as a negative control antibody, which specifically binds to chicken ovalbumin). Centrifuge to remove the supernatant, wash twice with FACS buffer, add secondary antibody (DyLight488 goat anti-mouse IgG, Abcam catalog number ab97015) and incubate at 4°C for 0.5 hours. After the staining is completed, centrifuge to remove the supernatant, wash twice with FACS buffer, resuspend the cells in FACS buffer, and then put the cells on the machine for reading. The experimental cells were measured and read using a flow cytometer (BD Company, model CantoII). During the measurement, first circle the cell position based on FCS and SSC, and then select the second antibody corresponding to the fluorescent channel and SSC to analyze the cells. The binding of mouse antibody 19H11 to MCF7 and Huh7 is shown in Figure 1A (MCF7) and 1B (Huh7).

Example 2: Variable region sequence determination of mouse anti-human CD24 antibody

Collect hybridoma cells by centrifugation. Add 1ml TRIzol and 0.2ml chloroform for every 5-10×10 ⁶ cells. Shake vigorously for 15 seconds and leave it at room temperature for 3 minutes. Centrifuge the water phase and add 0.5ml isopropyl alcohol. Leave it at room temperature for 10 minutes and collect the precipitate. After washing with ethanol, RNA was obtained by drying. Add the template RNA and primers to the centrifuge tube in an ice bath, make sure the primers and template are correctly paired, then perform the reverse transcription process and perform PCR amplification. Add 2.5 μl of dNTP/ddNTP mixture into each of the four microcentrifuge tubes, and incubate the mixture at 37°C for 5 minutes, and set aside. In an empty microcentrifuge tube, add 1 pmol of PCR amplified double-stranded DNA, 10 pmol of sequencing primer, 2 μl of 5× sequencing buffer, add double-distilled water to a total volume of 10 μl, heat at 96°C for 8 minutes, cool in ice bath for 1 minute, 4 Centrifuge at 10000g for 10 seconds. Add 2 μl of pre-cooled labeling mixture (0.75 μmol/L each of dCTP, dGTP, and dTTP), 5 μCi of α-32P-dATP, 1 μl of 0.1 mol/L DDT, and 2 U of sequencing enzyme. Add water to 15 μl. Mix well and place on ice for 2 minutes. Label newly synthesized DNA strands. Add 3.5 μl of the labeling reaction mixture to the four prepared microcentrifuge tubes, incubate at 37°C for 5 minutes, and add 4 μl of stop solution to each tube. The samples were thermally denatured in a water bath at 80°C for 5 minutes, and 2 μl of each lane was added to the sequencing gel. These fragments were separated by electrophoresis and sequence information was collected.

The VH and VL sequences of the mouse-derived antibodies are shown in Table 3. Further, the method described by Kabat et al. (Kabat et al., Sequences of Proteins of Immunological Interest, 5th ed., Public Health Service, National Institutes of Health, Bethesda, MD (1991), pp. 647-669 page), the CDR sequence of the mouse monoclonal antibody was determined.

Table 3: Sequence information of mouse-derived antibodies

Example 3: Recombinant expression of chimeric anti-CD24 antibodies

After the antibody gene sequence was verified, the variable region of the mouse antibody was connected to the constant region of the human antibody (human IgG4, whose heavy chain constant region and light chain constant region amino acid sequences are shown in SEQ ID NO: 11 and 12 respectively) , construct chimeric antibody ch19H11, and transfect the expression vector containing the antibody gene into mammalian cells. The supernatant of mammalian cells containing antibody clones grown in culture flasks was harvested, purified using a protein A column, and the antibody protein was eluted using 100mM acetic acid pH 3.0. The purified antibody protein is then loaded onto a size exclusion chromatography column for further separation and purification. Antibody proteins corresponding to the monomers were formulated in PBS buffer supplemented with 20% glycerol.

Example 4: Evaluation of antigen-binding activity of chimeric anti-CD24 antibodies

Flow cytometric evaluation of chimeric antibody binding to CD24:

Place 500,000 CD24 naturally expressing MCF7 cells in FACS buffer for later use, using a round-bottom low-adsorption 96-well plate. Antibody samples were serially diluted using FACS buffer. Add diluted antibodies to the cell plate (use ISO as a negative control antibody), add FACS buffer to the corresponding negative control wells, and incubate at 4°C for 1 hour. After centrifuging to remove the supernatant, wash twice with FACS buffer, add secondary antibody (DyLight488 goat anti-human IgG, Abcam catalog number ab97003) to each well, and incubate at 4°C for another 0.5 hours. After the staining is completed, centrifuge to remove the supernatant, wash twice with FACS buffer, add FACS buffer to each well to resuspend the cells, and then use the machine for reading. A flow cytometer (BD Company, model CantoII) was used to measure and read the cells in the experimental plate. When measuring, first circle the cell position based on FCS and SSC, then select the second antibody corresponding to the fluorescence channel and SSC to analyze the cells. Use GraphPad for data analysis. The abscissa uses the logarithm of the antibody concentration, and the ordinate uses the average fluorescence intensity value. According to the curve Fit the EC50 of the anti-CD24 antibody.

The binding of chimeric antibody ch19H11 to MCF7 is shown in Figure 2A. The results show that the chimeric antibody ch19H11 has good binding activity to CD24 on the membrane surface.

ELISA evaluation of chimeric antibodies binding to CD24:

1 μg/ml recombinant human CD24 protein-recombinant CD24 (Kaika Biotechnology, recombinant human CD24 protein) or chemically synthesized CD24-polypeptide CD24 (Gill Biochemical) was coated on an ELISA plate in PBS overnight at 4°C. Plates were washed 3 times in wash buffer (PBS, 0.05% Tween 20) and non-specific sites were saturated by adding 200 μl/w PBS + 2% BSA blocking. Add 100 μL of a dose range of anti-CD24 antibody gradient dilution to the antigen-coated ELISA plate and incubate at 37°C for 1 hour. Plates were washed 3 times in wash buffer 10 and HRP-conjugated goat anti-human IgG Fc fragment secondary antibody was added for 1 hr at room temperature to detect bound anti-CD24 antibodies. The plate was washed 3 times in wash buffer and bound secondary antibodies were revealed by adding TMB (HRP substrate) and incubating the plate in the dark at room temperature for 5 to 10 minutes. The enzymatic reaction was stopped by adding 1M sulfuric acid solution and the light absorption was measured at 450 nm. Draw a curve with the light absorption value as the ordinate and the logarithm of the antibody concentration as the abscissa, and use GraphPad Prism software to calculate EC50.

As shown in Figures 2B and 2C, chimeric antibody ch19H11 has good binding activity to both recombinantly expressed CD24 (Figure 2B) and chemically synthesized CD24 polypeptide (Figure 2C).

Example 5: Humanization of mouse anti-human CD24 antibody

In order to improve the sequence homology between the candidate antibody and the human antibody and reduce the immunogenicity of the antibody to humans, the mouse antibody provided in the above embodiments can be humanized designed and prepared using methods known in the art. Mouse CDR regions were inserted into human framework sequences (see Winter, U.S. Patent Nos. 5,225,539; Queen et al., U.S. Patent Nos. 5,530,101; 5,585,089; 5,693,762 and 6,180,370; and Lo, Benny, K.C., editor, in Antibody Engineering: Methods and Protocols , volume 248, Humana Press, New Jersey, 2004).

Specifically, the heavy chain and light chain CDR regions of the mouse antibody 19H11 were transplanted onto the FR framework of the corresponding humanized template, and a series of back mutations were performed on the amino acid residues in the FR region of the humanized template. , so that the humanized antibody retains the antigen-binding ability of the mouse antibody as much as possible. According to the above method, the inventors prepared a humanized antibody of mouse-derived antibody 19H11, named GB7011-05 (the amino acid sequences of its heavy chain variable region and light chain variable region are as shown in SEQ ID NO: 9 and 10 respectively. Show). The heavy chain constant region of the antibody is SEQ ID NO:11, and the light chain constant region is SEQ ID NO:12.

Example 6: Evaluation of antigen-binding activity of humanized anti-CD24 antibodies

Flow cytometric evaluation of humanized antibody binding to CD24:

500,000 CD24 naturally expressing tumor cells (human liver tumor cells Huh7; humanized breast tumor cells MCF7) were placed in FACS buffer for later use, using a round-bottom low-adsorption 96-well plate. Antibody samples were serially diluted using FACS buffer (using ISO as a negative control antibody). Add diluted antibodies to the cell plate and the corresponding negative Add FACS buffer to the control well and incubate at 4°C for 1 hour. After centrifuging to remove the supernatant, wash twice with FACS buffer, add secondary antibody (DyLight488 goat anti-human IgG, Abcam catalog number ab97003) to each well and incubate at 4°C for another 0.5 hours. After the staining is completed, centrifuge to remove the supernatant, wash twice with FACS buffer, add FACS buffer to each well to resuspend the cells, and then use the machine for reading. A flow cytometer (BD Company, model CantoII) was used to measure and read the cells in the experimental plate. When measuring, first circle the cell position based on FCS and SSC, then select the second antibody corresponding to the fluorescence channel and SSC to analyze the cells. Use GraphPad for data analysis. The abscissa uses the logarithm of the antibody concentration, and the ordinate uses the average fluorescence intensity value. According to the curve Fit the EC50 of the anti-CD24 antibody.

The binding of humanized antibody GB7011-05 to two tumor cells (Huh7/MCF7) that naturally express human CD24 is shown in Figure 3A (Huh7) and Figure 3B (MCF7) respectively. The results show that humanized antibody GB7011-05 binds well to CD24 on the surface of Huh7/MCF7.

Example 7: Anti-CD24 antibody blocks the binding of Siglec10 to CD24

Antibodies block the binding of Siglec10 to CD24 using fluorescently labeled Siglec-10 protein (ACRO biosystems catalog number SI0-HP2E5) as the receptor and HEK293T-CD24 cells (high-expressing human CD24; human embryonic kidney cell line) as the ligand , titrations were performed using flow cytometry measurements. The specific detection steps are to place 100,000 HEK293T-CD24 cells in 50 μL FACS buffer (PBS+2% FBS)/well for use. The experiment uses a round-bottom low-adsorption 96-well plate; the antibody sample is diluted in FACS buffer (use ISO as Negative control antibody), add 50 μL of diluted antibody to each well of the cell plate, add 50 μL of FACS buffer to the corresponding negative control well, and incubate at 4°C for 1 hour; after the first stage of incubation is completed, add 50 μL of fluorescently labeled Siglec to each well. -10 protein (final concentration 1/40, diluted in FACS buffer), continue to incubate at 4°C for 1 hour; after the incubation is completed, centrifuge to remove the supernatant, wash twice with FACS buffer, add 100 μL FACS buffer to each well, and resuspend the cells. A flow cytometer (BD Company, model CantoII) was used to measure and read the cells in the experimental plate. During the measurement, the cell position was first circled based on FCS and SSC, and then the fluorescently labeled protein was selected to correspond to the red fluorescence channel (PE) and SSC to analyze the cells. The effect of the chimeric antibody blocking Siglec10-CD24 binding was calculated based on the PE value. Use the value of the negative control well as the max value to calculate the ratio of the antibody blocking the binding of Siglec10 to CD24. The ratio of the antibody blocking binding = 100 × [(max – PE value) / max]. The higher the ratio, the higher the ratio of the measured anti-CD24 antibody resistance. The stronger the ability to block the binding of Siglec10 protein to CD24 high-expressing cell lines. On the contrary, the lower the value, the better the ability of the measured anti-CD24 antibody to block the binding of Siglec10 protein to CD24 high-expressing cell lines. GB7011-05 can effectively block the binding of CD24 on the cell membrane surface to its receptor protein Siglec10. The results are shown in Figure 4.

Example 8: Anti-CD24 antibody induces phagocytosis of tumor cells by macrophages

Using NALM6 cells as target cells and M1 or M2 macrophages as effector cells, flow cytometry was used to detect phagocytosis. The specific detection steps are: resuscitate PBMC cells (derived from healthy people, purchased from Miaoshun Biotechnology), and after culturing for 72 hours, discard the supernatant suspended cells. GM-CSF (nearshore protein, GMP-CC79) was added to stimulate for 8 days, and IFNγ (nearshore protein, C014) was used to stimulate for one day to obtain M1 macrophages. M-CSF (nearshore protein, C417) was added to stimulate for 7 days, and IL4 (nearshore protein, GMP-CD03) + IL10 (R&D, 217-IL-025) was used to stimulate for two days to obtain M2 macrophages. Digest and collect the processed macrophages, resuspend them in 1640 culture medium, and adjust the density to 5×10 ⁵ /ml. Take NALM6 cells (Fuheng Biotechnology, CRL-3273), wash them twice with DPBS, adjust the cell density to 1×10 ⁶ /ml, add CFSE dye (Thermo Scientific, C34554) with a final concentration of 1.6uM, and incubate at 37°C. Light stain for 20 minutes. Add 5 times the volume of 2% FBS-PBS and stop in the dark for 5 minutes, then centrifuge and wash twice with DPBS, resuspend in 1640 culture medium, and adjust the density to 1×10 ⁶ /ml. Antibody samples were diluted 5 times of the final concentration in 1640 medium (using ISO as a negative control antibody). Using a round-bottom low-adsorption 96-well plate (Corning, 7007), add 50ul of CFSE-stained NALM6 cell suspension and 25ul of diluted antibodies to the corresponding wells, and incubate at 37°C for 20 minutes. After the incubation is completed, add 50ul of macrophage suspension and let stand for 3 hours in a 37°C, 5% _CO2 cell culture incubator. Collect the cells by centrifugation at 1000 rpm for 5 minutes, remove the supernatant, add 5ug/ml APC-anti CD11b antibody (Biolegend, 101212) and incubate at 4°C for 30 minutes. Collect the cells by centrifugation at 1000 rpm for 5 minutes, remove the supernatant, wash twice with DPBS, and use a flow cytometer (BD Company, model CantoII) to detect the cells in the experimental plate. During the measurement, the cell positions were first circled based on FCS and SSC, and then the red fluorescent channel (APC) corresponding to CD11b-labeled macrophages and the green fluorescent channel (FITC) corresponding to CFSE-labeled NALM6 cells were selected to analyze the cells. According to the double-positive gate of APC and FITC The cell ratio defines the percentage of NALM6 tumor cells that do not undergo phagocytosis. The higher the ratio of double-positive cells, the better the ability of the measured anti-CD24 antibody to induce phagocytosis, and vice versa.

The phagocytosis of NALM6 tumor cells by M1 macrophages and M2 macrophages induced by anti-CD24 antibody GB7011-05 is shown in Figure 5A (M1) and Figure 5B (M2), in which Anti-CD47 5F9 is recombinantly expressed An antibody targeting CD47 to induce macrophage phagocytosis. The antibody sequence is derived from Magrolimab (Forty Seven).

Although the specific embodiments of the present invention have been described in detail, those skilled in the art will understand that various modifications and changes can be made to the details based on all teachings that have been published, and these changes are within the protection scope of the present invention. . The full scope of the present invention is given by the appended claims and any equivalents thereof.

Claims

An antibody or an antigen-binding fragment thereof capable of specifically binding to CD24, the antibody or an antigen-binding fragment thereof comprising:

A repeat containing a VH CDR1 as set forth in SEQ ID NO:3 or a variant thereof, a VH CDR2 as set forth in SEQ ID NO:4 or a variant thereof, and a VH CDR3 as set forth in SEQ ID NO:5 or a variant thereof Chain variable region (VH); and/or, comprising VL CDR1 as set forth in SEQ ID NO:6 or a variant thereof, VL CDR2 as set forth in SEQ ID NO:7 or a variant thereof, and SEQ ID NO: The light chain variable region (VL) of the VL CDR3 shown in 8 or a variant thereof;

Wherein, the variant has one or several amino acid substitutions, deletions or additions compared to the sequence from which it is derived (for example, 1, 2 or 3 amino acid substitutions, deletions or additions);

Preferably, the substitutions are conservative substitutions.
The antibody or antigen-binding fragment thereof according to claim 1, wherein the antibody or antigen-binding fragment thereof comprises:

(a) The following three heavy chain variable region CDRs: VH CDR1 as shown in SEQ ID NO:3, VH CDR2 as shown in SEQ ID NO:4, and VH CDR3 as shown in SEQ ID NO:5; and/or, the following three light chain variable region CDRs: VL CDR1 as shown in SEQ ID NO:6, VL CDR2 as shown in SEQ ID NO:7, VL CDR3 as shown in SEQ ID NO:8 ;or,

(b) The following three heavy chain variable region CDRs: VH CDR1, VH CDR2 and VH CDR3 contained in the heavy chain variable region shown in SEQ ID NO: 1 or 9; and/or, the following three light Chain variable region CDRs: VL CDR1, VL CDR2 and VL CDR3 contained in the light chain variable region shown in SEQ ID NO:2 or 10;

Preferably, the three CDRs contained in the heavy chain variable region and the three CDRs contained in the light chain variable region are defined by the Kabat, Chothia or IMGT numbering system.
The antibody or antigen-binding fragment thereof according to claim 1 or 2, wherein the antibody or antigen-binding fragment thereof comprises:

A heavy chain variable region (VH) comprising the sequence shown in SEQ ID NO: 1 or a variant thereof; and/or a light chain variable region (VL) comprising the sequence shown in SEQ ID NO: 2 or a variant thereof );

Wherein, the variant has one or several amino acid substitutions, deletions or additions compared to the sequence from which it is derived (for example, 1, 2, 3, 4 or 5 amino acid substitutions, deletions or additions) , or have at least 80%, at least 85%, Sequences that have at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity;

Preferably, the substitution is a conservative substitution;

Preferably, the antibody or antigen-binding fragment thereof comprises:

VH containing the sequence shown in SEQ ID NO:1 and VL containing the sequence shown in SEQ ID NO:2.
The antibody or antigen-binding fragment thereof according to any one of claims 1 to 3, wherein the antibody or antigen-binding fragment thereof comprises a framework region sequence derived from human immunoglobulin;

Preferably, the antibody or antigen-binding fragment thereof comprises: a heavy chain framework sequence derived from a human heavy chain germline sequence, and a light chain framework sequence derived from a human light chain germline sequence.
The antibody or antigen-binding fragment thereof according to claim 4, wherein the antibody or antigen-binding fragment thereof comprises:

A heavy chain variable region (VH) comprising the sequence shown in SEQ ID NO: 9 or a variant thereof; and/or a light chain variable region (VL) comprising the sequence shown in SEQ ID NO: 10 or a variant thereof );

Wherein, the variant has one or several amino acid substitutions, deletions or additions compared to the sequence from which it is derived (for example, 1, 2, 3, 4 or 5 amino acid substitutions, deletions or additions) , or have at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% , or a sequence with 100% sequence identity;

Preferably, the substitution is a conservative substitution;

Preferably, the antibody or antigen-binding fragment thereof comprises:

A VH containing the sequence set forth in SEQ ID NO:9 and a VL containing the sequence set forth in SEQ ID NO:10.
The antibody or antigen-binding fragment thereof according to any one of claims 1 to 5, wherein the antibody or antigen-binding fragment thereof further comprises a constant region derived from human immunoglobulin;

Preferably, the heavy chain of the antibody or antigen-binding fragment thereof comprises a heavy chain constant region derived from a human immunoglobulin (eg, IgG1, IgG2, IgG3 or IgG4), and the light chain of the antibody or antigen-binding fragment thereof comprises a source In the light chain constant region of a human immunoglobulin (such as kappa or lambda);

Preferably, the antibody or antigen-binding fragment thereof comprises the heavy chain constant region (CH) shown in SEQ ID NO: 11;

Preferably, the antibody or antigen-binding fragment thereof comprises the light chain constant region (CL) shown in SEQ ID NO: 12.
The antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, wherein the antigen-binding fragment is selected from the group consisting of Fab, Fab', (Fab') 2 , Fv, disulfide-linked Fv, scFv, bis Antibodies (diabodies) and single domain antibodies (sdAb); and/or, the antibodies are murine antibodies, chimeric antibodies, humanized antibodies, bispecific antibodies or multispecific antibodies.
The antibody or antigen-binding fragment thereof according to any one of claims 1-7, wherein the antibody or antigen-binding fragment thereof includes a detectable label, such as an enzyme (such as horseradish peroxidase), a radionuclide, Fluorescent dyes, luminescent substances (such as chemiluminescent substances) or biotin.
An isolated nucleic acid molecule encoding the antibody or antigen-binding fragment thereof according to any one of claims 1 to 8, or its heavy chain variable region and/or light chain variable region.
A vector comprising the isolated nucleic acid molecule of claim 9; preferably, the vector is a cloning vector or an expression vector.
A host cell comprising the isolated nucleic acid molecule of claim 9 or the vector of claim 10.
A method for preparing the antibody or antigen-binding fragment thereof according to any one of claims 1 to 8, comprising culturing the host cell according to claim 11 under conditions that allow expression of the antibody or antigen-binding fragment thereof, and The antibody or antigen-binding fragment thereof is recovered from the cultured host cell culture.
A bispecific or multispecific molecule comprising the antibody or antigen-binding fragment thereof according to any one of claims 1-8;

Preferably, the bispecific or multispecific molecule specifically binds CD24 and additionally specifically binds one or more other targets;

Preferably, the bispecific or multispecific molecule further comprises at least one molecule having a second binding specificity for a second target (eg a second antibody).
An immunoconjugate comprising the antibody or antigen-binding fragment thereof according to any one of claims 1-8 and a therapeutic agent connected to the antibody or antigen-binding fragment thereof;

Preferably, the therapeutic agent is selected from cytotoxic agents;

Preferably, the therapeutic agent is selected from the group consisting of alkylating agents, mitotic inhibitors, anti-tumor antibiotics, antimetabolites, topoisomerase inhibitors, tyrosine kinase inhibitors, radionuclide agents, and any combination thereof;

Preferably, the immunoconjugate is an antibody-drug conjugate (ADC).
A chimeric antigen receptor comprising the antigen-binding domain of the antibody or antigen-binding fragment thereof according to any one of claims 1-8;

Preferably, the antigen-binding domain comprises the heavy chain variable region and the light chain variable region of the antibody or antigen-binding fragment thereof according to any one of claims 1-8;

Preferably, the antigen-binding domain is scFv;

Preferably, the chimeric antigen receptor comprises an antigen-binding fragment of the antibody of any one of claims 1-8;

Preferably, the chimeric antigen receptor is expressed by immune effector cells (eg T cells).
An isolated nucleic acid molecule encoding the chimeric antigen receptor of claim 15.
A vector comprising the isolated nucleic acid molecule of claim 16; preferably, it is used to prepare chimeric antigen receptor T cells.
A host cell expressing the chimeric antigen receptor of claim 15 and/or comprising the isolated nucleic acid molecule of claim 16 or the vector of claim 17;

Preferably, the host cells are immune effector cells (e.g., T cells and/or NK cells);

Preferably, the host cell is a chimeric antigen receptor T cell (CAR-T).
Pharmaceutical composition, which contains the antibody or antigen-binding fragment thereof according to any one of claims 1 to 8, the isolated nucleic acid molecule according to claim 9, the vector according to claim 10, and the host according to claim 11 cells, power The bispecific or multispecific molecule of claim 13, the immunoconjugate of claim 14, the chimeric antigen receptor of claim 15, the isolated nucleic acid molecule of claim 16, the The vector of claim 17 or the host cell of claim 18, and pharmaceutically acceptable carriers and/or excipients;

Preferably, the pharmaceutical composition further comprises an additional pharmaceutically active agent;

Preferably, the additional pharmaceutically active agent is a drug with anti-tumor activity, such as alkylating agents, mitotic inhibitors, anti-tumor antibiotics, antimetabolites, topoisomerase inhibitors, tyrosine kinase inhibitors, radioactive Nuclides, radiosensitizers, anti-angiogenic agents, cytokines, antibodies specifically targeting tumor cells, immune checkpoint inhibitors or immunomodulators;

Preferably, the additional pharmaceutically active agent is an immune checkpoint inhibitor;

Preferably, the additional pharmaceutically active agent is an anti-PD-1 antibody or an anti-PD-L1 antibody.
A method for enhancing an immune response or preventing and/or treating tumors in a subject (e.g., a human), the method comprising administering to the subject an effective amount of any one of claims 1-8 The antibody or antigen-binding fragment thereof, the isolated nucleic acid molecule of claim 9, the vector of claim 10, the host cell of claim 11, the bispecific or multispecific molecule of claim 13 , the immunoconjugate of claim 14, the chimeric antigen receptor of claim 15, the isolated nucleic acid molecule of claim 16, the vector of claim 17, the host of claim 18 Cells, or the pharmaceutical composition of claim 19;

Preferably, the tumor involves CD24-positive tumor cells, and/or involves CD24 ligand (such as Siglec-10)-positive macrophages;

Preferably, the tumor is a solid tumor, such as breast cancer (e.g., triple negative breast cancer), ovarian cancer, liver cancer, lung cancer, colorectal cancer, gastric cancer, pancreatic cancer, bladder cancer, prostate cancer, renal cell carcinoma, cervical cancer , endometrial cancer, cholangiocarcinoma, kidney cancer, nasopharyngeal cancer, thyroid cancer, brain cancer, testicular cancer, bone cancer, lymphoma or glioma;

Preferably, the tumor is a hematological tumor, such as leukemia, lymphoma, myeloma;

Preferably, the method further comprises administering a second therapeutic agent (such as a drug with anti-tumor activity) or a second treatment (such as surgery, chemotherapy, radiotherapy, targeted therapy, immunotherapy, hormone therapy, gene therapy or Palliative care);

Preferably, the second therapeutic agent is an immune checkpoint inhibitor;

Preferably, the second therapeutic agent is an anti-PD-1 antibody or an anti-PD-L1 antibody.
A method for killing or depleting CD24-positive cells in a subject (such as a human), the method comprising administering to the subject an effective amount of the antibody or antigen thereof according to any one of claims 1-8 Binding fragment, isolated nucleic acid molecule of claim 9, vector of claim 10, host cell of claim 11, bispecific or multispecific molecule of claim 13, claim 14 The immunoconjugate of claim 15, the isolated nucleic acid molecule of claim 16, the vector of claim 17, the host cell of claim 18, or the The pharmaceutical composition described in 19.
The antibody or antigen-binding fragment thereof according to any one of claims 1 to 8, the isolated nucleic acid molecule according to claim 9, the vector according to claim 10, the host cell according to claim 11, the host cell according to claim 13 The bispecific or multispecific molecule described in claim 14, the chimeric antigen receptor described in claim 15, the isolated nucleic acid molecule described in claim 16, the immunoconjugate described in claim 17 The vector, the host cell of claim 18, or the pharmaceutical composition of claim 19, in the preparation of a medicament for enhancing immune response or preventing and/or treating tumors in a subject (such as a human) use;

Preferably, the tumor involves CD24-positive tumor cells, and/or involves CD24 ligand (such as Siglec-10)-positive macrophages;

Preferably, the tumor is a solid tumor, such as breast cancer (e.g., triple negative breast cancer), ovarian cancer, liver cancer, lung cancer, colorectal cancer, gastric cancer, pancreatic cancer, bladder cancer, prostate cancer, renal cell carcinoma, cervical cancer , endometrial cancer, cholangiocarcinoma, kidney cancer, nasopharyngeal cancer, thyroid cancer, brain cancer, testicular cancer, bone cancer, lymphoma or glioma;

Preferably, the tumor is a hematological tumor, such as leukemia, lymphoma, myeloma;

Preferably, the antibody or antigen-binding fragment thereof, isolated nucleic acid molecule, vector, host cell, bispecific or multispecific molecule, immunoconjugate, chimeric antigen receptor, isolated nucleic acid molecule, vector, host The combined administration of cells, or pharmaceutical compositions, with additional pharmaceutically active agents (e.g., drugs with anti-tumor activity); preferably, the additional pharmaceutically active agents are immune checkpoint inhibitors;

Preferably, the antibody or antigen-binding fragment thereof, isolated nucleic acid molecule, vector, host cell, bispecific or multispecific molecule, immunoconjugate, chimeric antigen receptor, isolated nucleic acid molecule, vector, host Cells, or pharmaceutical compositions are administered in combination with anti-PD-1 antibodies or anti-PD-L1 antibodies.
The antibody or antigen-binding fragment thereof according to any one of claims 1 to 8, the isolated nucleic acid molecule according to claim 9, the vector according to claim 10, the host cell according to claim 11, the host cell according to claim 13 The bispecific or multispecific molecule described in claim 14, the chimeric antigen receptor described in claim 15, the isolated nucleic acid molecule described in claim 16, the immunoconjugate described in claim 17 The use of the vector, the host cell of claim 18, or the pharmaceutical composition of claim 19 in the preparation of a medicament for killing or depleting CD24-positive cells in a subject (eg, a human).
A kit containing the antibody or antigen-binding fragment thereof according to any one of claims 1-8;

Preferably, the antibody or antigen-binding fragment thereof carries a detectable label, such as an enzyme (such as horseradish peroxidase), a radionuclide, a fluorescent dye, a luminescent substance (such as a chemiluminescent substance) or biotin;

Preferably, the kit further includes a second antibody that specifically recognizes the antibody or antigen-binding fragment thereof according to any one of claims 1 to 8; preferably, the second antibody further includes a detectable label, Examples include enzymes (eg horseradish peroxidase), radionuclides, fluorescent dyes, luminescent substances (eg chemiluminescent substances) or biotin.
A method for detecting the presence or amount of CD24 in a sample, comprising the following steps:

(1) contacting the sample with the antibody or antigen-binding fragment thereof according to any one of claims 1-8;

(2) detecting the formation of a complex between the antibody or its antigen-binding fragment and CD24 or detecting the amount of the complex;

Preferably, the method is used to diagnose whether a subject has a CD24-expressing tumor;

Preferably, the method is used to detect whether the tumor can be treated by anti-tumor therapy targeting CD24;

Preferably, the tumor is a solid tumor, such as breast cancer (e.g., triple negative breast cancer), ovarian cancer, liver cancer, lung cancer, colorectal cancer, gastric cancer, pancreatic cancer, bladder cancer, prostate cancer, renal cell carcinoma, cervical cancer , endometrial cancer, cholangiocarcinoma, kidney cancer, nasopharyngeal cancer, thyroid cancer, brain cancer, testicular cancer, bone cancer, lymphoma or glioma;

Preferably, the tumor is a hematological tumor, such as leukemia, lymphoma, myeloma.
Use of the antibody or antigen-binding fragment thereof according to any one of claims 1 to 8 or the kit according to claim 24 in preparing a detection reagent for determining the presence or amount of CD24 in a sample , diagnosing whether a subject has a CD24-expressing tumor, and/or testing whether the tumor can be treated with an anti-tumor therapy targeting CD24. treatment;

Preferably, the tumor is a solid tumor, such as breast cancer (e.g., triple negative breast cancer), ovarian cancer, liver cancer, lung cancer, colorectal cancer, gastric cancer, pancreatic cancer, bladder cancer, prostate cancer, renal cell carcinoma, cervical cancer , endometrial cancer, cholangiocarcinoma, kidney cancer, nasopharyngeal cancer, thyroid cancer, brain cancer, testicular cancer, bone cancer, lymphoma or glioma;

Preferably, the tumor is a hematological tumor, such as leukemia, lymphoma, myeloma.