Anti-CD39 antibodies and uses thereof

Abstract

The present disclosure provides an antibody or antigen-binding fragment thereof that specifically binds CD39 and inhibits soluble CD39 protease activity without inhibiting membrane-bound CD39 enzyme activity.

Description

[0001] This application is a divisional application of the invention patent application for anti-CD39 antibodies and their uses, with the application date of December 27, 2023; application number: 202311834233.7; and the invention name: Anti-CD39 antibodies and their uses. Technical Field

[0002] The present disclosure relates to the field of antibodies, and more particularly to an antibody against CD39. Background Art

[0003] CD39, also known as ectonucleoside triphosphate diphosphohydrolase 1 (ENTPDase1), converts ATP or ADP into AMP, which is then dephosphorylated to adenosine by CD73. Adenosine is a potent immunosuppressant and binds to adenosine receptors (e.g., A2A receptors) located on the surface of CD4, CD8 T cells, and natural killer (NK) cells, and inhibits T cell and NK cell responses, thereby suppressing the immune system. Adenosine also binds to A2A or A2B receptors on macrophages and dendritic cells, inhibits phagocytosis and antigen presentation, and increases the secretion of tumor-promoting factors (e.g., VEGF, TGFb, and IL-6). Elevated adenosine levels mediated by CD39 and CD73 create an immunosuppressive environment, thereby promoting the occurrence and development of cancer. In addition, CD39 is also constitutively present in human and mouse blood as a soluble enzyme and promotes the metabolism of ADP together with other purinergic enzymes.

[0004] CD39 is widely expressed in various tissues and organs, such as bladder, brain, breast, colon, uterus, stomach, prostate, etc., and is mainly expressed in endothelial cells and immune cells. CD39 is highly expressed in various human tumors, including lymphoma, sarcoma, lung cancer, pancreatic cancer, ovarian cancer, renal cell carcinoma, thyroid cancer and testicular cancer. In addition to the effector T cells and NK cells mentioned above, CD39's regulatory function on the immune system is also manifested in macrophages, MDSC, neutrophils, regulatory T cells, antigen-presenting cells and other cells. CD39 is associated with immunosuppression and immune exhaustion in most immune cells, while knocking out CD39 can upregulate the secretion of immune factors, inhibit the activity of regulatory T cells and stimulate the function of immune cells.

[0005] Given the important role CD39 plays in the tumor microenvironment, it has become an emerging target for researchers to develop tumor immunotherapy. In the tumor microenvironment, blocking adenosine-mediated immunosuppression by targeting CD39 can inhibit tumor growth.

[0006] Currently, public data show that antibodies targeting CD39 inhibit both soluble CD39 and membrane-bound CD39. The antibodies screened by this patent only inhibit the protease activity of soluble CD39, but not the enzyme activity of membrane-bound CD39. Since CD39 is widely expressed in tissues, CD39 antibodies have certain safety risks as antibody drugs, but the characteristics of the antibodies screened by this patent eliminate this risk and improve the safety of antibody drugs. Summary of the invention

[0007] In view of the above problems, the present disclosure provides antibodies, preparation methods, compositions, etc. The benefits provided by the present disclosure are widely applicable to the field of antibody therapy and diagnosis, and can be used in combination with antibodies that react with various targets. The present invention provides antibodies that can specifically bind to human CD39 antigen.

[0008] The present invention discloses an isolated antibody or an antigen-binding fragment thereof, wherein the antibody or the antigen-binding fragment thereof specifically binds to CD39 and comprises a heavy chain variable region (VH) and a light chain variable region (VL),

[0009] The heavy chain variable region comprises:

[0010] (i) a HCDR1 comprising a sequence having at least 80%, at least 85%, at least 95%, or 100% sequence identity to one of SEQ ID NOs: 21-24 or consisting of SEQ ID NOs: 21-24; and

[0011] (ii) a HCDR2 comprising or consisting of a sequence having at least 80%, at least 85%, at least 95%, or 100% sequence identity to one of SEQ ID NOs: 25-28; and

[0012] (iii) a HCDR3 comprising or consisting of a sequence having at least 80%, at least 85%, at least 95%, or 100% sequence identity to one of SEQ ID NOs: 29-32;

[0013] The light chain variable region comprises:

[0014] (i) LCDR1 comprising or consisting of a sequence having at least 80%, at least 85%, at least 95%, or 100% sequence identity to one of SEQ ID NOs: 33-36; and

[0015] (ii) LCDR2 comprising or consisting of a sequence having at least 60%, at least 65%, at least 75%, at least 95%, or 100% sequence identity to one of SEQ ID NOs: 37-40; and

[0016] (iii) LCDR3 comprising or consisting of a sequence having at least 80%, at least 85%, at least 95%, or 100% sequence identity to one of SEQ ID NOs: 41-44.

[0017] In some embodiments of the present invention, the antibody or fragment comprises the following combination:

[0018] (i) HCDR1 shown in SEQ ID NO:21, HCDR2 shown in SEQ ID NO:25, and HCDR3 shown in SEQ ID NO:29, LCDR1 shown in SEQ ID NO:33, LCDR2 shown in SEQ ID NO:37, and LCDR3 shown in SEQ ID NO:41; or

[0019] (ii) HCDR1 set forth in SEQ ID NO:22, HCDR2 set forth in SEQ ID NO:26, and HCDR3 set forth in SEQ ID NO:30, LCDR1 set forth in SEQ ID NO:34, LCDR2 set forth in SEQ ID NO:38, and LCDR3 set forth in SEQ ID NO:42; or

[0020] (iii) HCDR1 set forth in SEQ ID NO:23, HCDR2 set forth in SEQ ID NO:27, and HCDR3 set forth in SEQ ID NO:31, LCDR1 set forth in SEQ ID NO:35, LCDR2 set forth in SEQ ID NO:39, and LCDR3 set forth in SEQ ID NO:43; or

[0021] (iv) HCDR1 shown in SEQ ID NO:24, HCDR2 shown in SEQ ID NO:28, and HCDR3 shown in SEQ ID NO:32, LCDR1 shown in SEQ ID NO:36, LCDR2 shown in SEQ ID NO:40, and LCDR3 shown in SEQ ID NO:44.

[0022] In some embodiments of the invention, the antibody or fragment, wherein the heavy chain variable region comprises a sequence having 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 100% sequence identity to one of SEQ ID NOs: 12-15 or consists of one of SEQ ID NOs: 12-15;

[0023] wherein the light chain variable region comprises a sequence having 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 100% sequence identity to one of SEQ ID NOs: 17-20 or consists of one of SEQ ID NOs: 17-20.

[0024] In some embodiments of the present invention, the antibody or fragment comprises the following combination:

[0025] (i) VH shown in SEQ ID NO: 12, VL shown in SEQ ID NO: 17; or

[0026] (ii) VH shown in SEQ ID NO: 13, VL shown in SEQ ID NO: 18; or

[0027] (iii) VH shown in SEQ ID NO: 14, VL shown in SEQ ID NO: 19; or

[0028] (iv) VH shown in SEQ ID NO: 15, VL shown in SEQ ID NO: 20.

[0029] An antibody or fragment as described in any of the preceding claims, further comprising a heavy chain constant region and a light chain constant region, the heavy chain constant region is selected from IgG1, IgG2, IgG3, or IgG4 constant region, the light chain constant region is selected from κ or λ light chain constant region, the heavy chain constant region is preferably selected from IgG1 constant region, and the light chain constant region is preferably selected from κ chain constant region.

[0030] In some embodiments of the present invention, the antibody or fragment comprises:

[0031] a heavy chain comprising or consisting of a sequence having 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 to one of SEQ ID NOs: 3, 5, 7, 9;

[0032] A light chain comprising or consisting of a sequence having 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 to one of SEQ ID NOs: 4, 6, 8, 10.

[0033] In some embodiments of the present invention, the antibody or fragment comprises:

[0034] (i) the heavy chain shown in SEQ ID NO: 3, and the light chain shown in SEQ ID NO: 4; or

[0035] (ii) the heavy chain shown in SEQ ID NO: 5, and the light chain shown in SEQ ID NO: 6; or

[0036] (iii) the heavy chain shown in SEQ ID NO:7, and the light chain shown in SEQ ID NO:8; or (iv) the heavy chain shown in SEQ ID NO:9, and the light chain shown in SEQ ID NO:10.

[0037] In some embodiments of the present invention, the antibody or fragment, wherein the antibody is a whole antibody, a bispecific antibody, a monoclonal antibody, a chimeric antibody, a humanized antibody and a fully human antibody.

[0038] In some embodiments of the present invention, the antibody or fragment, wherein the antigen-binding fragment is selected from the following groups: Fab fragment, Fab' fragment, F(ab) 2 Fragments, Fv fragments and ScFv.

[0039] In some embodiments of the present invention, the antibody or fragment inhibits the protease activity of soluble CD39 but does not inhibit the enzyme activity of membrane-bound CD39.

[0040] On the other hand, the present invention also provides an isolated nucleic acid molecule comprising a nucleic acid sequence encoding the antibody or fragment.

[0041] On the other hand, the present invention also provides a vector comprising the nucleic acid molecule.

[0042] On the other hand, the present invention also provides a host cell, comprising the nucleic acid molecule or the vector.

[0043] In another aspect, the present invention also provides a conjugate comprising the antibody or fragment coupled to at least one detectable label.

[0044] In another aspect, the present invention also provides an antibody drug conjugate comprising an antibody, wherein the antibody comprises one or more drug moieties, wherein the drug moieties are covalently linked to the antibody or fragment directly or via a linker.

[0045] On the other hand, the present invention also provides a multispecific molecule, which comprises the antibody or antigen-binding fragment; preferably, the multispecific molecule specifically binds to CD39, and additionally specifically binds to one or more other targets; further preferably, the multispecific molecule also comprises at least one molecule having a second binding specificity for a second target.

[0046] On the other hand, the present invention also provides a pharmaceutical composition or kit, comprising the antibody or fragment, or the nucleic acid molecule, or the vector, or the host cell, or the conjugate, or the antibody-drug conjugate, or the multispecific molecule, and a pharmaceutically acceptable carrier.

[0047] On the other hand, the present invention also provides use of the antibody or fragment, or the nucleic acid molecule, or the vector, or the host cell, or the conjugate, or the antibody-drug conjugate, or the multispecific molecule, or the pharmaceutical composition or kit in the preparation of a kit for diagnosing, detecting or monitoring diseases related to CD39 expression.

[0048] On the other hand, the present invention also provides use of the antibody or fragment, or the nucleic acid molecule, or the vector, or the host cell, or the conjugate, or the antibody-drug conjugate, or the multispecific molecule, or the pharmaceutical composition or kit in the preparation of a drug for treating a disease related to CD39 expression or determining its prognosis.

[0049] On the other hand, in the above-mentioned use, the disease associated with CD39 expression is cancer, and the cancer is selected from the following group: lymphoma, sarcoma, lung cancer, pancreatic cancer, ovarian cancer, renal cell carcinoma, thyroid cancer and testicular cancer.

[0050] The antibodies screened by this patent only inhibit the protease activity of soluble CD39, but not the enzyme activity of membrane-bound CD39. Since CD39 is widely expressed in tissues, CD39 antibodies have certain safety risks as antibody drugs, but the characteristics of the antibodies screened by this patent eliminate this risk and improve the safety of antibody drugs. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are used to provide further understanding of the present disclosure and constitute a part of the specification. They are used to explain the present disclosure together with the embodiments of the present disclosure and do not constitute a limitation of the present disclosure.

[0052] Figure 1 The results of the binding activity of the chimeric antibody of the present invention to the Human CD39 protein are shown;

[0053] Figure 2 The results of the cell-level binding activity of the chimeric antibody of the present invention are shown;

[0054] Figure 3 The results of protease inhibition activity of the chimeric antibody of the present invention are shown. DETAILED DESCRIPTION

[0055] In order to make those skilled in the art better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only illustrative embodiments of a part of the present invention, rather than all embodiments. Therefore, the present invention is not limited to the specific embodiments illustrated. In addition, any section titles used herein are not to be construed as limiting the subject matter described.

[0056] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention will have the meanings commonly understood by those of ordinary skill in the art. In addition, unless the context requires otherwise, terms in the singular shall include plural forms, and terms in the plural shall include singular forms. More specifically, as used in this specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" include plural indicators. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "comprising" and other forms (such as "including" and "containing") is not restrictive. In addition, the ranges provided in the specification and the appended claims include endpoints and all values ​​between the endpoints.

[0057] definition

[0058] In order to better understand the present invention, definitions and explanations of relevant terms are provided below.

[0059] The term "antibody" or "Ab" generally refers to a Y-shaped tetrameric protein comprising two heavy (H) and two light (L) polypeptide chains held together by covalent disulfide bonds and non-covalent interactions. The light chains of antibodies can be divided into κ or λ light chains. The heavy chains can be divided into μ, δ, γ, α or ε, which define the isotype of the antibody as IgM, IgD, IgG, IgA or IgE, respectively. In the light and heavy chains, the variable region is connected to the constant region by a "J" region of about 12 or more amino acids, and the heavy chain also contains a "D" region of about 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 VH and VL regions can be further divided into hypervariable regions (called complementary determining regions, or CDRs) separated by relatively conserved regions (called framework regions, or FRs). Each VH and VL consists of 3 CDRs and 4 FRs in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4 from N-terminus to C-terminus. The CDRs on VH are HCDR1, HCDR2, and HCDR3; the CDRs on VL are LCDR1, LCDR2, and LCDR3. The variable regions (VH and VL) of each heavy chain / light chain pair form antigen binding sites / parts, respectively. The distribution of amino acids in various regions or domains follows the numbering definitions in common systems such as Kabat, IMGT, or Chothia. In the specific embodiments of the present disclosure, the CDR sequences are determined using the numbering definitions in the Kabat system.

[0060] Antibodies in the present disclosure also include antigen binding portions (interchangeably used with the term "antigen binding fragment"). Antigen binding portions refer to polypeptides comprising fragments of intact antibodies that retain the ability to specifically bind to an antigen that specifically binds to a full-length or intact antibody, and / or that compete with a full-length antibody for binding to the same antigen. Under some conditions, antigen binding portions include Fab, Fab', F(ab')2, Fd, Fv, dAb and complementary determining region (CDR) fragments, single-chain antibodies (e.g., scFv), chimeric antibodies, diabodies, and antibodies that contain at least a portion of an antibody sufficient to confer specific antigen binding ability to a polypeptide. The antigen binding portion of an antibody can be obtained from a given antibody by conventional techniques known to those skilled in the art (e.g., recombinant DNA techniques or enzymatic or chemical cleavage methods), and can be screened for specificity in the same manner as intact antibodies.

[0061] The term "isotype" refers to the antibody class (eg, IgM or IgG1) encoded by the heavy chain constant region genes.

[0062] The term "monoclonal antibody" or "mAb" refers to an antibody molecule / preparation of single molecular composition. A monoclonal antibody displays a single binding specificity and affinity for a particular epitope. The antibodies of the present invention may be derived from different species, including but not limited to mouse, rat, rabbit, guinea pig and human.

[0063] The term "epitope" refers to an antigenic determinant in a molecule, which refers to a portion of a molecule that is recognized by the immune system (eg, by an antibody), such as a discontinuous three-dimensional site on an antigen recognized by the immune system. In the present invention, the epitope is, for example, the CD39 protein.

[0064] The term "chimeric antibody" as used herein refers to an antibody whose variable region sequence is from one species and the constant region sequence is from another species, for example, an antibody in which the variable region sequence is derived from a mouse antibody and the constant region sequence is derived from a human antibody.

[0065] The term "humanized antibody" is intended to refer to antibodies in which CDR sequences / antigen binding portions or sites derived from the germline of another mammalian species, such as a mouse, have been grafted onto human framework sequences. In addition, additional framework region modifications may also be made within the human framework sequences.

[0066] "Fully human" or "completely human" means that all human antibody-encoding genes are transferred to genetically engineered antibody gene-deficient animals through transgenic or transchromosome technology, so that the animals express human antibodies and achieve the purpose of fully humanized antibodies. It usually refers to antibodies with antibody regional therapeutic agents derived from fully human amino acid sequences, in which antigen specificity has been selected in vivo by using genetically modified mice or by antibody engineering methods combined with screening. Compared with humanized antibodies, fully human antibodies have a lower risk of inducing immune responses in humans, stronger specific immune effects, and higher ADCC activity, CDC activity and / or CD39 binding stability.

[0067] The term "KD value" is the equilibrium dissociation constant between an antibody and its antigen, i.e., the ratio of koff / kon or kd / ka (determined by SPR technology). Therefore, the lower the KD value (the lower the concentration), the higher the affinity of the antibody. Therefore, the "KD value" can be used to measure the binding affinity between an antibody and its antigen.

[0068] The terms "CD39" and "CD39 antigen" are used interchangeably herein and include any variants, isoforms, and species homologs of human CD39 that are naturally expressed by cells or expressed on cells transfected with the CD39 gene. In some embodiments, the binding of the antibodies of the present disclosure to the CD39 antigen mediates killing of cells expressing CD39 (e.g., tumor cells) by inactivating CD39. Killing of cells expressing CD39 may occur by one or more of the following mechanisms: cell death / apoptosis induction, ADCC, and CDC.

[0069] The term "anti-CD39 antibody" or "CD39 antibody" refers to an antibody capable of binding to the CD39 antigen or to a cell expressing CD39 as defined herein.

[0070] The term "specific binding" refers to a non-random binding reaction between two molecules, such as the reaction between an antibody and its antigen.

[0071] The term "isolated" refers to a state obtained from a natural state by artificial means. If a certain "isolated" substance or component exists in nature, it may be because its natural environment has changed, or the substance has been separated from the natural environment, or both. For example, a certain unisolated polynucleotide or polypeptide exists naturally in a living organism, and the same polynucleotide or polypeptide with high purity separated from this natural state is called an isolated polynucleotide or polypeptide. The term "isolated" neither excludes mixed artificial or synthetic substances, nor excludes other impure substances that do not affect the activity of the isolated substance. For example, an isolated antibody may be substantially free of other cellular materials and / or chemicals.

[0072] The term "vector" refers to a nucleic acid vector into which a polynucleotide can be inserted. When a vector allows the expression of a protein encoded by a polynucleotide inserted therein, the vector is called an expression vector. The vector can be transformed, transduced or transfected into a host cell to express the genetic material elements carried in the host cell. Vectors are well known to those skilled in the art, and include but are not limited to plasmids, bacteriophages, cosmids, artificial chromosomes such as yeast artificial chromosomes (YAC), bacterial artificial chromosomes (BAC) or P1-derived artificial chromosomes (PAC); bacteriophages such as lambda phage or M13 phage and animal viruses. Animal viruses that can be used as vectors include but are not limited to retroviruses (including lentiviruses), adenoviruses, adeno-associated viruses, herpes viruses (such as herpes simplex virus), poxviruses, baculoviruses, papillomaviruses, papovaviruses (such as SV40). The vector may contain multiple elements for controlling expression, including but not limited to promoter sequences, transcription initiation sequences, enhancer sequences, selection elements and reporter genes. In addition, the vector may contain an origin of replication. As for the vector for expressing the antibody, a vector type in which the antibody heavy chain and light chain exist in different vectors or a vector type in which the heavy chain and light chain exist in the same vector can be used.

[0073] The term "host cell" refers to a cell system that can be engineered to produce a target protein, protein fragment or peptide. Host cells include, but are not limited to, cultured cells, such as cultured mammalian cells derived from rodents (rat, mouse, guinea pig or hamster), such as CHO, BHK, NSO, SP2 / 0, YB2 / 0; or human tissue or hybridoma cells, yeast cells and insect cells, as well as cells contained in transgenic animals or cultured tissues. The term covers not only specific test cells, but also the offspring of such cells. Because certain modifications may occur in subsequent generations due to mutations or environmental influences, such offspring may be different from the parental cells, but are still included in the scope of the term "host cell".

[0074] The term "identity" refers to the relationship between the sequences of two or more polypeptide molecules (or protein molecules) or two or more nucleic acid molecules determined by alignment and comparison of the sequences. "Percent identity" refers to the percentage of identical residues between amino acids or nucleotides in the compared molecules and is calculated based on the size of the smallest molecules being compared. For these calculations, gaps in the alignment, if any, are preferably addressed by a specific mathematical model or computer program (i.e., an "algorithm"). Methods that can be used to calculate the identity of aligned nucleic acids or polypeptides include those described in Computational Molecular Biology, (Lesk, AM, ed.), 1988, New York: Oxford University Press; Biocomputing Informatics and Genome Projects, (Smith, DW, ed.), 1993, New York: Academic Press; Computer Analysis of Sequence Data, Part I, (Griffin, AM, and Griffin, HG, eds.), 1994, New Jersey: Humana Press; von Heinje, G., 1987, Sequence Analysis in Molecular Biology, New York: Academic Press; Sequence Analysis Primer, (Gribskov, M. and Devereux, J., eds.), 1991, New York: M. Stockton Press; and Carillo et al, 1988, SIAM J. Applied Math. 48:1073.

[0075] The term "immunogenicity" refers to the ability to stimulate the formation of specific antibodies or sensitized lymphocytes in an organism. It not only refers to the property of antigens to stimulate the activation, proliferation and differentiation of specific immune cells to ultimately produce immune effector substances such as antibodies and sensitized lymphocytes, but also refers to the specific immune response of antibodies or sensitized T lymphocytes that can be formed in the immune system of an organism after stimulating the organism with an antigen. Immunogenicity is the most important property of an antigen. Whether an antigen can successfully induce the generation of an immune response in a host depends on three factors: the nature of the antigen, the reactivity of the host and the means of immunity.

[0076] The term "transfection" refers to the process of introducing nucleic acids into eukaryotic cells, particularly mammalian cells. Protocols and techniques for transfection include, but are not limited to, lipid transfection and chemical and physical methods such as electroporation. Many transfection techniques are well known in the art and disclosed herein. See, for example, Graham et al., 1973, Virology 52:456; Sambrook et al., 2001, Molecular Cloning: A Laboratory Manual, supra; Davis et al., 1986, Basic Methods in Molecular Biology, Elsevier; Chu et al, 1981, Gene 13:197.

[0077] The term "hybridoma" and the term "hybridoma cell line" are used interchangeably. When referring to the term "hybridoma" and the term "hybridoma cell line", they also include subclones and progeny cells of the hybridoma.

[0078] The term "immune effector function" includes any function mediated by components of the immune system that results in inhibition of tumor growth and / or inhibition of tumorigenesis, including inhibition of tumor dissemination and metastasis. Preferably, the immune effector function results in killing tumor cells. Preferably, the immune effector function in the present invention is an antibody-mediated effector function. Such functions include complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), induction of apoptosis in cells carrying tumor-associated antigens (e.g., by binding of antibodies to surface antigens) and / or inhibition of proliferation of cells carrying tumor-associated antigens, preferably ADCC and / or CDC. Antibodies can also simply act by binding to tumor-associated antigens on the surface of tumor cells. For example, antibodies can block the function of tumor-associated antigens or induce apoptosis simply by binding to tumor-associated antigens on the surface of tumor cells.

[0079] The term "cancer" refers to any tumor or malignant cell growth, proliferation or metastasis-mediated solid tumors and non-solid tumors such as leukemia that cause medical conditions. For example, cancers associated with CD39 expression or caused by abnormal expression include, but are not limited to, lymphoma, sarcoma, lung cancer, pancreatic cancer, ovarian cancer, renal cell carcinoma, thyroid cancer and testicular cancer.

[0080] The term "pharmaceutically acceptable" means that the carrier, diluent, excipient and / or salt thereof is chemically and / or physically compatible with the other ingredients of the formulation and physiologically compatible with the recipient.

[0081] The term "pharmaceutically acceptable carrier and / or excipient" refers to a carrier and / or excipient that is pharmacologically and / or physiologically compatible with the subject and the active agent and is well known in the art (see, e.g., Remington's Pharmaceutical Sciences. Edited by Gennaro AR, 19 th Ed. Pennsylvania: Mack Publishing Company, 1995), and includes but is not limited to pH adjusters, surfactants, adjuvants and ionic strength enhancers. For example, pH adjusters 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.

[0082] The term "adjuvant" refers to a non-specific immunopotentiator, which can enhance the immune response to the antigen in the organism or change the type of immune response when it is delivered to the organism together with the antigen or delivered to the organism in advance. There are multiple adjuvants, including but not limited to aluminum adjuvants (such as aluminum hydroxide), Freund's adjuvants (such as Freund's complete adjuvant and Freund's incomplete adjuvant), Corynebacterium brevis, lipopolysaccharide, cytokines, etc. Freund's adjuvant is the most commonly used adjuvant in current animal experiments. Aluminum hydroxide adjuvant is more commonly used in clinical trials.

[0083] Anti-CD39 antibody

[0084] In some aspects, the invention includes isolated antibodies or antigen-binding fragments thereof.

[0085] In the context of the present application, "antibodies" may include polyclonal antibodies, monoclonal antibodies, chimeric antibodies, humanized and primatized antibodies, CDR-grafted antibodies, human antibodies, recombinantly produced antibodies, intracellular antibodies, bifunctional antibodies, multispecific antibodies, bispecific antibodies, monovalent antibodies, multivalent antibodies, anti-idiotypic antibodies, synthetic antibodies, including mutant proteins and variants thereof, improved antibodies; and derivatives thereof (including Fc fusion proteins and other modifications), as well as any other immunoreactive molecules, as long as they show preferential association or binding with CD39 protein. In addition, unless the context otherwise provides, the term also includes antibodies of all classes (i.e., IgA, IgD, IgE, IgG, and IgM) and all subclasses (i.e., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2). In a preferred embodiment, the antibody is a monoclonal antibody. In a more preferred embodiment, the antibody is a chimeric monoclonal antibody or a humanized monoclonal antibody or an improved chimeric monoclonal antibody.

[0086] The variable regions and CDRs in an antibody sequence can be identified according to the general rules (such as Kabat) numbering system developed in the art or by aligning the sequence with a database of known variable regions.

[0087] Regardless of how the antibody is produced, methods for testing the ability of an antibody to bind to an antigen (e.g., CD39) are known in the art and include any antibody-antigen binding assay, such as radioimmunoassay (RIA), ELISA, Western blot, immunoprecipitation, SPR, and competitive inhibition assays (see, e.g., Janeway et al., infra, and U.S. Patent Application Publication No. 2002 / 0197266 and the above section on competition assays).

[0088] According to the present invention, in a standard assay (such as the assay described in the present invention), if the antibody has a significant affinity to the predetermined target (such as CD39 protein or cells expressing CD39), the antibody is able to bind to the predetermined target. In order to test the binding of the monoclonal antibody to living cells expressing CD39, flow cytometry (FCM) can be used. Preferably, in a flow cytometric fluorescence sorting technique (FACS) analysis, the antibody is determined to bind to a target expressed on the cell surface. If the antibody can detectably bind to the target (CD39 protein or cells expressing CD39), the antibody is able to bind to the target and has "affinity".

[0089] The CD39 specificity described in the present invention refers to the ability to bind to one or more CD39 epitopes, especially CD39 epitopes in natural conformation, especially human CD39 specificity.

[0090] In the art, various methods are used to modify the desired properties of antibodies without changing them, such as the method used in the present disclosure of recombining the light chain and heavy chain of the antibody, replacing amino acids, etc. For example, the sequences of the present invention, including chimeric antibody sequences or humanized antibody sequences, can be subjected to conservative amino acid substitutions.

[0091] Antibodies interact with target antigens primarily through amino acid residues located in the six heavy and light chain complementary determining regions (CDRs). For this reason, the amino acid sequences of CDRs are more diverse between antibodies than other sequences. Since CDR sequences are responsible for most antibody-antigen interactions, it is possible to express recombinant antibodies that mimic the properties of a specific naturally occurring antibody by constructing an expression vector comprising CDR sequences from the specific naturally occurring antibody grafted onto framework sequences from different antibodies with different properties (see, e.g., Riechmann, L. et al. (1998) Nature 332: 323-327; Jones, P. et al. (1986) Nature 321: 522-525; and Queen, C. et al. (1989) Proc. Natl. Acad. Sci. USA 86: 10029-10033). Such framework sequences can be obtained from public DNA databases that include germline antibody gene sequences. These germ lines are sequences that are different from mature antibody gene sequences because they do not contain fully assembled variable genes, which are formed by V(D)J joining during B cell maturation. Germline gene sequences will also have sequences that are different from the high-affinity second antibody library (secondary repertoireantibody) at individual locations evenly across the variable region.

[0092] Mouse antibodies are highly immunogenic in humans, resulting in reduced therapeutic efficacy when used repeatedly, with the main immunogenicity mediated by the heavy chain constant region. If the individual antibodies are chimerized or humanized, the immunogenicity of mouse antibodies in humans can be reduced or completely avoided.

[0093] Chimeric antibodies refer to antibodies in which different parts are from different animal species, for example, antibodies with variable regions from mouse antibodies and human immunoglobulin constant regions. The variable regions of mouse antibody heavy and light chains are linked together with the constant regions of human heavy and light chains to obtain the chimeric nature of the antibody (for example, as described in Kraus et al., in Methods in Molecular Biology series, Recombinant antibodies for cancer therapy ISBN-0-89603-918-8). In a preferred embodiment, chimeric antibodies are produced by connecting human kappa light chain constant regions to mouse light chain variable regions. In another preferred embodiment, chimeric antibodies can be produced by connecting human lambda light chain constant regions to mouse light chain variable regions.

[0094] Humanized antibodies are antibodies in which CDR sequences / antigen-binding portions or sites derived from the germline of another mammalian species, such as a mouse, are grafted onto human framework sequences.

[0095] In order to reduce the immunogenicity of the antibody to humans, the sequence of the CD39 antibody of the present disclosure is used to produce a humanized anti-CD39 antibody, and the CDR region of the anti-CD39 antibody of mouse origin is combined with the framework region of human origin (e.g., human immunoglobulin) to form the humanized anti-CD39 antibody of the present disclosure. The humanized antibody is expected to retain the function of binding to human CD39 as well as the function of binding to monkey CD39.

[0096] Preparation or generation of antibodies

[0097] The antibodies of the present invention can be produced by a variety of techniques, including conventional monoclonal antibody methods, such as the standard somatic cell hybridization technique of Kohler and Milstein, Nature 256: 495 (1975). Although hybridoma technology is preferred, in principle, other techniques for producing monoclonal antibodies can be used, such as virus or oncogene transformation of B lymphocytes or phage display technology using antibody gene libraries, somatic cell hybridization methods, and for example, obtaining through genetic engineering recombination technology. For example, DNA molecules encoding the heavy chain and light chain genes of the antibodies of the present invention are obtained by chemical synthesis or PCR amplification, the resulting DNA molecules are inserted into expression vectors, and then transfected into host cells, and then, the transfected host cells are cultured under specific conditions, and the antibodies of the present invention are expressed.

[0098] Other preferred animal systems for preparing hybridomas that secrete monoclonal antibodies are rat and rabbit systems (described, for example, in Spieker-Polet et al., Proc. Natl. Acad. Sci. USA 92: 9348 (1995), see also Rossie et al.. Am. J. Clin. Pathol. 124: 295 (2005)). Hybridoma production in mice is a very well established method. Immunization protocols and techniques for isolating immunized spleen cells for fusion are known in the art. Fusion partners (e.g., mouse myeloma cells) and fusion methods are also known.

[0099] Monoclonal antibodies can be prepared using a variety of techniques known in the art, including hybridoma technology, recombinant technology, phage display technology, transgenic animals or some combination thereof. For example, hybridomas and biochemical and genetic engineering techniques recognized in the art can be used to produce monoclonal antibodies, as described in detail in An, Zhiqiang (ed.) Therapeutic Monoclonal Antibodies: From Bench to Clinic, John Wiley and Sons, 1st ed.2009; Shire et al. (eds.) Current Trends in Monoclonal Antibody Development and Manufacturing, Springer Science + Business Media LLC, 1st ed.2010; Harlow et al., Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory Press, 2nd ed.1988; Hammerling, et al., in: Monoclonal Antibodies and T-Cell Hybridomas 563-681 (Elsevier, NY, 1981), each of which is incorporated herein by reference in its entirety.

[0100] It should be understood that the selected binding sequence can be further altered, for example, to increase affinity for the target, humanize the target binding sequence, improve its production in cell culture, reduce its immunogenicity in vivo, generate multispecific antibodies, etc., and antibodies comprising altered target binding sequences are also antibodies of the present invention.

[0101] In some embodiments, the method of producing the antibodies or fragments described herein comprises the following steps:

[0102] (i) expressing the antibody or fragment in a host cell; and optionally

[0103] (ii) isolating the antibody or antigen-binding fragment thereof from the host cell.

[0104] In a preferred embodiment, anti-CD39 monoclonal antibodies are produced by using hybridomas.

[0105] In order to obtain hybridomas that produce antibodies of the invention, such as human monoclonal antibodies of the invention, spleen cells and / or lymph node cells from immunized mice can be isolated and fused to a suitable immortalized cell line, such as a mouse myeloma cell line. The resulting hybridomas are screened for the production of antigen-specific antibodies. The production of hybridomas is well known in the art. See, for example, Harlow and Lane (1988) Antibodies, A Laboratory Manual, Cold Spring Harbor Publications, New York.

[0106] The antibodies of the present invention can also be produced in host cell transfectomas using, for example, a combination of recombinant DNA technology and gene transfection methods well known in the art (e.g., Morrison, S. (1985) Science 229: 1202). In some embodiments, DNA encoding partial or full-length light and heavy chains obtained by standard molecular biology techniques is inserted into one or more expression vectors so that the genes are operably linked to transcriptional and translational regulatory sequences. In this context, the term "operably linked" is intended to mean that the antibody gene is linked to the vector so that the transcriptional and translational control sequences within the vector perform their intended functions of regulating transcription and translation of the antibody gene.

[0107] The antibody light chain gene and the antibody heavy chain gene can be inserted into the same or different expression vectors.In some embodiments, the variable region is used to produce the full-length antibody gene of any antibody isotype by inserting it into the expression vector of the heavy chain constant region and the light chain constant region encoding the desired isotype, so that the VH segment is operably connected to the CH segment and the VL segment in the carrier are operably connected to the CL segment in the carrier.In addition or alternatively, the recombinant expression vector can encode the signal peptide that promotes the secretion of the antibody chain from the host cell.The antibody chain gene can be cloned into a vector so that the signal peptide is connected to the amino terminal of the antibody chain gene.The signal peptide can be an immunoglobulin signal peptide or a heterologous signal peptide (i.e., a signal peptide from a non-immunoglobulin protein).

[0108] To express the light and heavy chains, expression vectors encoding the heavy and light chains are transfected into host cells by standard techniques. The various forms of the term "transfection" are intended to encompass various techniques commonly used to introduce exogenous DNA into prokaryotic or eukaryotic host cells, such as electroporation, calcium phosphate precipitation, DEAE-dextran transfection, etc. The antibodies of the present invention can be expressed in prokaryotic or eukaryotic host cells, such as mammalian host cells, which can assemble and secrete appropriately folded and immunologically active antibodies.

[0109] Mammalian host cells for expressing the recombinant antibodies of the invention include Chinese hamster ovary cells (CHO cells) (including dhfr CHO cells described in Urlaub and Chasin, (1980) Proc. Natl. Acad. Sci. USA 77: 4216-4220) used with a DHFR selection marker (e.g., as described in RJ Kaufman and PA Sharp (1982) J. MoI. Biol. 159: 601-621), NSO myeloma cells, COS cells and SP2 cells. In particular, for use with NSO myeloma, another expression system is the GS gene expression system disclosed in WO 87 / 04462, WO 89 / 01036 and EP 338,841. When a recombinant expression vector encoding an antibody gene is introduced into a mammalian host cell, the antibody is produced by culturing the host cell for a period of time sufficient to allow the antibody to be expressed in the host cell or secreted into the culture medium in which the host cell is grown. The antibody can be recovered from the culture medium using standard protein purification methods.

[0110] In another preferred embodiment, transgenic or transchromosomal mice carrying parts of the human immune system (rather than the mouse system) can be used to generate human monoclonal antibodies against CD39.

[0111] Another strategy for generating monoclonal antibodies is to directly isolate the gene encoding the antibody from the lymphocytes producing antibodies of a defined strategy, see for example Babcock et al., 1996; A novel strategy for generating monoclonal antibodies from single, isolated lymphocytes producing antibodies of defined strategy. For details of recombinant antibody engineering, see also Welschof and Krau, Recombinant antibodies for cancer therapy ISBN-0-89603-918-8 and Benny KC Lo Antibody Engineering ISBN 1-58829-092-1.

[0112] To prepare chimeric antibodies, murine immunoglobulin variable regions can be linked to human immunoglobulin constant regions using methods known in the art (see, e.g., U.S. Pat. No. 4,816,567 to Cabilly et al.). The isolated nucleic acid encoding the VH region can be converted into a full-length heavy chain gene by operably linking the nucleic acid encoding the VH to another DNA molecule encoding the heavy chain constant region (CH1, CH2, and CH3). The sequences of human heavy chain constant region genes are known in the art (see, e.g., Kabat et al. (1991), Sequences Of Proteins of Immunological Interest, Fifth Edition, US Department of Health and Human Services, NIH Publication No. 91-3242). The heavy chain constant region can be an IgG1, IgG2, IgG3, IgG4, IgA, IgE, IgM, or IgD constant region, but more preferably an IgG1 or IgG4 constant region. The isolated nucleic acid encoding the VL region can be converted into a full-length light chain gene (as well as a Fab light chain gene) by operably linking the DNA encoding the VL to another DNA molecule encoding the light chain constant region CL. The sequences of human light chain constant region genes are known in the art (see, e.g., Kabat et al., supra), and DNA fragments comprising these regions can be obtained by standard PCR amplification. In a preferred embodiment, the light chain constant region can be a kappa or lambda constant region, but is generally preferably a kappa constant region. Once DNA fragments encoding VH and VL segments are obtained, these DNA fragments can be further manipulated by standard recombinant DNA techniques, such as converting variable region genes into full-length antibody chain genes, Fab fragment genes, or scFv genes. In these operations, the DNA fragment encoding VL or VH is operably connected to another DNA fragment encoding another protein, such as an antibody constant region or a flexible linker. The term "operably connected" as used herein is intended to indicate that two DNA fragments are connected so that the amino acid sequences encoded by the two DNA fragments remain in frame.

[0113] To prepare humanized antibodies, mouse CDR regions can be inserted into human framework sequences using methods known in the art (see Winter, U.S. Pat. No. 5,225,539; Queen et al., U.S. Pat. No. 5,530,101; U.S. Pat. No. 5,585,089; U.S. Pat. No. 5,693,762; and Lo, Benny, KC, editor, in Antibody Engineering: Methods and Protocols, volume 248, Humana Press, New Jersey, 2004). Alternatively, transgenic animals can be used that are capable of not producing endogenous immunoglobulins after immunization and are capable of producing a complete human antibody repertoire. For example, it has been reported that the homozygous deletion of the antibody heavy-chain joining region (JH) gene in chimeric and germ-line mutant mice can completely inhibit endogenous antibody production, and then transfer of the human germ-line immunoglobulin gene array into the germ-line mutant mice will result in the mice producing human antibodies when challenged with antigen (see, e.g., Jakobovits et al., 1993, Proc. Natl. Acad. Sci. USA 90:2551; Jakobovits et al., 1993, Nature 362:255-258; Bruggermann et al., 1993, Year in Immunology 7:33; and Duchosal et al., 1992, Nature 355:258). Non-limiting examples of the above transgenic animals include, HuMAb mice (Medarex, Inc.), which contain human immunoglobulin gene miniloci encoding unrearranged human heavy chain (μ and γ) and κ light chain immunoglobulin sequences, plus targeted mutations that inactivate endogenous μ and κ chain loci (see, e.g., Lonberg et al. (1994) Nature 368 (6474): 856-859); or "KM mice TM" carrying human heavy chain transgenes and human light chain transchromosomes (see patent application WO02 / 43478). Other methods for antibody humanization include phage display technology (Hoogenboom et al., 1991, J. Mol. Biol. 227: 381; Marks et al., J. Mol. Biol. 1991, 222: 581-597; Vaughan et al., 1996, Nature Biotech 14: 309).

[0114] Nucleic acid molecules encoding the antibodies of the present invention

[0115] In some aspects, the present invention relates to an isolated nucleic acid molecule comprising a nucleic acid sequence encoding the above-mentioned isolated antibody or fragment thereof as disclosed herein.

[0116] Nucleic acids of the present invention can be obtained using standard molecular biology techniques. For hybridoma-expressed antibodies (e.g., hybridomas prepared by transgenic mice carrying human immunoglobulin genes as further described below), cDNA encoding the light and heavy chains of antibodies prepared by hybridomas can be obtained by standard PCR amplification or cDNA cloning techniques. For antibodies obtained from immunoglobulin gene libraries (e.g., using phage display technology), nucleic acids encoding such antibodies can be recovered from gene libraries.

[0117] In order to prepare chimeric antibodies, methods known in the art can be used to connect the mouse immunoglobulin variable region to the human immunoglobulin constant region (see, for example, U.S. Pat. No. 4,816,567 to Cabilly et al.). The isolated nucleic acid encoding the VH region can be converted into a full-length heavy chain gene by operably connecting the nucleic acid encoding the VH to another DNA molecule encoding the heavy chain constant region (CH1, CH2 and CH3), and DNA fragments containing these regions can be obtained by standard PCR amplification. The isolated nucleic acid encoding the VL region can be converted into a full-length light chain gene (and a Fab light chain gene) by operably connecting the DNA encoding the VL to another DNA molecule encoding the light chain constant region CL. Once the DNA fragments encoding the VH and VL segments are obtained, these DNA fragments can be further manipulated by standard recombinant DNA techniques, such as converting the variable region gene into a full-length antibody chain gene, a Fab fragment gene or a scFv gene. In these operations, the DNA fragment encoding VL or VH is operably connected to another DNA fragment encoding another protein, such as an antibody constant region or a flexible linker.

[0118] Conjugate

[0119] In one aspect, the present disclosure provides a conjugate comprising an antibody or fragment thereof as described above coupled to at least one detectable marker. Detectable markers include, but are not limited to: (i) providing a detectable signal; (ii) interacting with a second marker to modify the detectable signal provided by the first or second marker, such as FRET (Fluorescence Resonance Energy Transfer); (iii) affecting mobility (e.g., electrophoretic mobility) by charge, hydrophobicity, shape or other physical parameters, or (iv) providing a capture moiety, such as affinity, antibody / antigen or ion complexation.

[0120] Suitable structures as labels include fluorescent labels, luminescent labels, chromophore labels, radioisotope labels, isotope labels, preferably stable isotope labels, isobaric labels, enzyme labels (such as horseradish peroxidase, alkaline phosphatase, β-galactosidase, urease, glucose oxidase, etc.), particle labels (especially metal particle labels, magnetic particle labels, polymer particle labels), organic small molecules (such as biotin, receptor ligands or binding molecules (such as cell adhesion proteins or phosphatidylcholine), which can be used to bind The marker sequence containing nucleic acid and / or amino acid residues can be detected by the marker. The marker includes, but is not limited to, barium sulfate, iodine, iopanoic acid, amiopromide calcium, diatrizoate sodium, diatrizoate meglumine, meglumine, sodium tyropanate, and radiodiagnostic agents (including positron emitters, (e.g., fluorine-18 and carbon-11), gamma emitters (e.g., iodine-123, iodine-125, technetium-99m, iodine-131 and indium-111), nuclear magnetic resonance nuclides (e.g., fluorine and gadolinium)), luminescent substances (e.g., isoluminol and acridinium esters), fluorescent substances (e.g., fluorescein and rhodamine), and colored substances (e.g., latex particles and colloidal gold).

[0121] Detectable labels as described above can be detected by methods known in the art. For example, fluorescent markers can be detected using a photodetector to detect emitted light. Enzyme labels are generally detected by providing a substrate to the enzyme and detecting the reaction product produced by the action of the enzyme on the substrate. In certain embodiments, such labels can be suitable for immunological detection (e.g., enzyme-linked immunosorbent assay, radioimmunoassay, fluorescent immunoassay, chemiluminescent immunoassay, etc.). In certain embodiments, detectable labels as described above can be connected to antibodies or antigen-binding fragments thereof of the present invention by linkers of varying lengths to reduce potential steric hindrance.

[0122] Antibody Drug Conjugates / Immunoconjugates

[0123] On the one hand, the present disclosure provides an antibody-drug conjugate comprising an antibody, which includes one or more drug moieties / therapeutic agents, wherein the drug moieties are directly or via a linker (e.g., covalently linked) to an antibody or fragment thereof as described above. In the antibody-drug conjugate of the present application, the linker structure for conjugating the anti-CD39 antibody to the drug is not particularly limited, as long as the resulting antibody-drug conjugate can be used.

[0124] Since antibody-drug conjugates have the ability to selectively deliver one or more drugs to target tissues (e.g., tumor-associated antigens, such as tumors expressing CD39), antibody-drug conjugates can improve the therapeutic efficacy of the antibodies or antigen-binding fragments thereof of the present invention in treating diseases (e.g., cancer).

[0125] Multispecific molecules

[0126] The antibodies or antigen-binding fragments thereof of the present invention can be used to form multispecific molecules (e.g., bispecific molecules). The antibodies or antigen-binding fragments thereof of the present invention can be part of a multispecific molecule (e.g., a bispecific molecule), wherein the bispecific or multispecific molecule comprises a second functional module (e.g., a second antibody) or a third functional module (e.g., a third antibody) having a binding specificity different from that of the antibodies or antigen-binding fragments thereof of the present invention, thereby being able to bind to at least two different binding sites and / or target molecules. For example, the antibodies or antigen-binding fragments thereof of the present invention can be connected to a second antibody or antigen-binding fragment thereof that can specifically bind to any protein that can be used as a potential target for combined therapy. To produce the bispecific or multispecific molecules, the antibodies or antigen-binding fragments thereof of the present invention can be connected (e.g., by chemical coupling, genetic fusion, non-covalent association or other means) to one or more other binding molecules (e.g., additional antibodies, antibody fragments, peptides, or binding mimetics).

[0127] Thus, in some aspects, the invention provides a multispecific molecule comprising an antibody or antigen-binding fragment thereof of the invention.

[0128] In certain preferred embodiments, the multispecific molecule specifically binds CD39 (eg, human CD39 or monkey CD39) and specifically binds one or more additional targets.

[0129] In certain preferred embodiments, the multispecific molecule further comprises at least one molecule having a second binding specificity for a second target (eg, a second antibody).

[0130] In certain preferred embodiments, the multispecific molecule is a bispecific antibody.

[0131] Pharmaceutical composition

[0132] In some aspects, the present invention relates to a pharmaceutical composition. The present disclosure provides a pharmaceutical composition or kit comprising the antibody or fragment as described above, the nucleic acid molecule as described above, the vector as described above, the host cell as described above, the conjugate as described above, the antibody-drug conjugate as described above, the multispecific molecule as described above; and a pharmaceutically acceptable carrier.

[0133] The pharmaceutical composition may optionally contain one or more additional pharmaceutically active ingredients, such as another antibody or drug. The pharmaceutical composition of the present invention may also be administered in combination with, for example, another immunostimulant, anticancer agent, antiviral agent or vaccine, so that the anti-CD39 antibody enhances the immune response to the vaccine. Pharmaceutically acceptable carriers may include, for example, pharmaceutically acceptable liquids, gels or solid carriers, aqueous media, non-aqueous media, antimicrobial agents, isotonic agents, buffers, antioxidants, anesthetics, suspending / dispersing agents, chelating agents, diluents, adjuvants, excipients or non-toxic auxiliary substances, combinations of various components known in the art or more.

[0134] Suitable components may include, for example, antioxidants, fillers, binders, disintegrants, buffers, preservatives, lubricants, flavoring agents, thickeners, colorants, emulsifiers or stabilizers such as sugars and cyclodextrins. Suitable antioxidants may include, for example, methionine, ascorbic acid, EDTA, sodium thiosulfate, platinum, catalase, citric acid, cysteine, mercaptoglycerol, thioglycolic acid, mercaptosorbitol, butylmethylanisole, butylated hydroxytoluene and / or propyl arsenate. As disclosed in the present invention, in a solvent containing an antibody or its antigen-binding fragment of the composition disclosed in the present invention containing one or more antioxidants such as methionine that reduce the antibody or its antigen-binding fragment, it may be oxidized. Redox can prevent or reduce the reduction of binding affinity, thereby enhancing antibody stability and extending shelf life. Therefore, in some embodiments, the present invention provides a composition comprising one or more antibodies or their antigen-binding fragments and one or more antioxidants such as methionine. The present invention further provides methods wherein the antibodies or antigen-binding fragments thereof are mixed with one or more antioxidants such as methionine, whereby the antibodies or antigen-binding fragments thereof can be protected from oxidation to extend their shelf life and / or increase their activity.

[0135] To further illustrate, pharmaceutically acceptable carriers can include, for example, aqueous vehicles such as sodium chloride injection, Ringer's injection, isotonic dextrose injection, sterile water injection, or dextrose and lactated Ringer's injection, non-aqueous vehicles such as fixed oils of vegetable origin, cottonseed oil, corn oil, sesame oil, or peanut oil, antimicrobial agents at bacteriostatic or fungistatic concentrations, isotonic agents such as sodium chloride or dextrose, buffers such as phosphate or citrate buffers, antioxidants such as sodium bisulfate, local anesthetics such as procaine hydrochloride, suspending and dispersing agents such as sodium carboxymethylcellulose, hydroxypropyl methylcellulose or polyvinylpyrrolidone, emulsifiers such as polysorbate 80 (TWEEN-80), partitioning agents or chelating agents such as EDTA (ethylenediaminetetraacetic acid) or EGTA (ethylene glycol tetraacetic acid), ethanol, polyethylene glycol, propylene glycol, sodium hydroxide, hydrochloric acid, citric acid or lactic acid. Antimicrobial agents used as carriers can be added to pharmaceutical compositions in multiple dose containers comprising phenols or cresols, mercurials, benzyl alcohol, chlorobutanol, methyl and propyl parabens, thimerosal, benzalkonium chloride and benzethonium chloride. Suitable excipients can include, for example, water, saline, dextrose, glycerol or ethanol. Suitable nontoxic auxiliary substances can include, for example, wetting agents or emulsifiers, pH buffers, stabilizers, solubility enhancers or reagents such as sodium acetate, sorbitan monolaurate, triethanolamine oleate or cyclodextrins.

[0136] Administration, formulation and dosage

[0137] The pharmaceutical compositions of the present invention can be administered to a subject in need thereof in vivo by various routes, including but not limited to oral, intravenous, intraarterial, subcutaneous, parenteral, intranasal, intramuscular, intracranial, intracardiac, intraventricular, intratracheal, oral, rectal, intraperitoneal, intradermal, topical, transdermal and intrathecal, or by implantation or inhalation. The compositions of the present invention can be formulated into solid, semisolid, liquid or gaseous preparations; including but not limited to tablets, capsules, powders, granules, ointments, solutions, suppositories, enemas, injections, inhalants and aerosols. Suitable preparations and routes of administration can be selected according to the intended application and treatment regimen.

[0138] Suitable formulations for enteral administration include hard or soft gelatin capsules, pills, tablets (including coated tablets), elixirs, suspensions, syrups or inhalants and controlled release forms thereof.

[0139] Preparations suitable for parenteral administration (e.g., by injection) include aqueous or non-aqueous, isotonic, pyrogen-free, sterile liquids (e.g., solutions, suspensions) in which the active ingredient is dissolved, suspended, or otherwise provided (e.g., in liposomes or other microparticles). These liquids may additionally contain other pharmaceutically acceptable ingredients, such as antioxidants, buffers, preservatives, stabilizers, bacteriostats, suspending agents, thickeners, and solutes that make the preparation isotonic with the blood (or other relevant body fluids) of the intended recipient. Examples of excipients include, for example, water, alcohol, polyols, glycerol, vegetable oils, etc. Examples of isotonic carriers suitable for such preparations include sodium chloride injection, Ringer's solution, or lactated Ringer's injection. Similarly, specific dosage regimens (including dosage, time, and repetition) will depend on specific individuals and individual medical history as well as empirical considerations such as pharmacokinetics (e.g., half-life, clearance, etc.).

[0140] The requirements for effective pharmaceutical carriers for injectable formulations / compositions are well known to those of ordinary skill in the art (see, e.g., Pharmaceutics and Pharmacy Practice, JB Lippincott Company, Philadelphia, PA, eds. Banker and Chalmers, pp. 238-250 (1982), and ASHP Handbook on Injectable Drugs, Toissel, 4th ed., pp. 622-630 (1986)).

[0141] The frequency of administration can be determined and adjusted during the course of treatment and is based on reducing the number of proliferating or tumorigenic cells, maintaining the reduction of such tumor cells, reducing the proliferation of tumor cells or delaying the development of metastasis. In some embodiments, the dose administered can be adjusted or reduced to control potential side effects and / or toxicity. Alternatively, a sustained continuous release formulation of the therapeutic composition of the present invention may be suitable.

[0142] Those skilled in the art will appreciate that the appropriate dosage may vary from patient to patient. Determining the optimal dosage generally involves a balance between the level of therapeutic benefit and any risk or adverse side effects. The selected dosage level will depend on a variety of factors, including but not limited to the activity of the specific compound, administration, administration time, compound clearance rate, duration of treatment, other drugs, compounds and / or materials used in combination, severity of the condition, and species, sex, age, weight, condition, general health and previous medical history of the patient. However, the dosage is generally selected to achieve a local concentration at the site of action that achieves the desired effect without causing substantial harmful or adverse side effects.

[0143] Generally, the antibodies or antigen-binding fragments thereof of the present invention can be administered in various ranges.

[0144] In certain preferred embodiments, the course of treatment involving the antibodies or antigen-binding fragments thereof of the present invention will include multiple doses of the selected pharmaceutical product administered over a period of weeks or months. More specifically, the antibodies or antigen-binding fragments thereof of the present invention may be administered every day, every two days, every four days, every week, every ten days, every two weeks, every three weeks, every month, every six weeks, every two months, every ten weeks or every three months. In this regard, it is understood that the dosage may be changed or the interval may be adjusted based on patient response and clinical practice.

[0145] Compatible formulations for parenteral administration (eg, intravenous injection) will contain an antibody or antigen-binding fragment thereof as disclosed herein at a concentration of about 5 μg / mL to about 100 mg / mL.

[0146] The antibodies of the present invention can be co-administered with one or more other therapeutic agents (e.g., cytotoxic agents, radiotoxic agents, anti-tumor agents, anti-angiogenic agents or and immunosuppressants) to reduce the induction of an immune response against the antibodies of the present invention. The antibody can be linked to the therapeutic agent (as an immune complex) or can be administered separately from the therapeutic agent.

[0147] In the context of administering a treatment, the term "combination" or "co-administration" as used herein refers to the use of more than one treatment or therapeutic agent. The use of the term "combination" does not limit the order in which the treatment or therapeutic agent is administered to a subject. The treatment or therapeutic agent may be administered before, simultaneously, or after the second treatment or therapeutic agent is administered to the patient. Preferably, the treatment or therapeutic agent is administered to the subject in a certain order, amount, and / or within a certain time interval so that the treatment or therapeutic agent can work together. In a specific embodiment, the treatment or therapeutic agent is administered to the subject in a certain order, amount, and / or within a certain time interval so that they provide an increased benefit than if they were administered in other ways (particularly independently of each other). Preferably, the increased benefit is a synergistic effect.

[0148] Medical Uses

[0149] The antibodies, antibody compositions and methods of the invention have many in vitro and in vivo uses, including, for example, detection of CD39 or enhancement of immune responses. For example, these molecules can be administered to cultured cells in vitro or ex vivo, or, for example, administered to human subjects in vivo.

[0150] Preferred subjects include mammals, such as humans / patients. Mammals in the context of the present invention are humans, non-human primates, domesticated animals such as dogs, cats, sheep, cows, goats, pigs, horses, etc., laboratory animals such as mice, rats, rabbits, guinea pigs, etc., and captive animals, such as zoo animals.

[0151] Treating conditions associated with CD39 expression

[0152] In some aspects, the invention provides methods of treating a disorder in a mammal comprising administering to a subject (eg, a human) in need of treatment a therapeutically effective amount of an antibody or antigen-binding fragment thereof disclosed herein.

[0153] As described herein, the antibodies disclosed herein have one or more activities that can be therapeutically applied to kill cells and / or inhibit cells. In particular, killing cells, inhibiting the proliferation of cells and / or inhibiting the colony formation of cells can be used to treat or prevent cancer (including cancer metastasis). Inhibiting the proliferation, colony formation and / or metastasis of cells can be applied, especially for treating or preventing cancer metastasis and metastatic spread of cancer cells.

[0154] In some aspects, the present disclosure provides a method for treating a disease associated with CD39 expression or determining its prognosis in a subject, comprising administering an effective dose of the antibody or antigen-binding fragment thereof, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, the multispecific molecule, or the pharmaceutical composition or kit to a subject in need thereof.

[0155] In some aspects, the present disclosure provides the antibody or antigen-binding fragment thereof, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, the multispecific molecule, or the pharmaceutical composition or kit for use in a method for treating a disease associated with CD39 expression or determining the prognosis thereof in a subject.

[0156] In some aspects, the present disclosure provides use of the antibody or antigen-binding fragment thereof, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, the multispecific molecule, or the pharmaceutical composition or kit in the preparation of an agent (or drug) for treating a disease associated with CD39 expression or determining the prognosis thereof.

[0157] In one embodiment, the disease associated with CD39 expression includes a tumor disease, such as cancer.

[0158] The antibodies or antigen-binding fragments thereof can be used alone as a monotherapy or can be used in combination with chemotherapy or radiation therapy.

[0159] The antibodies or antigen-binding fragments thereof can be used in combination with anticancer agents, cytotoxic agents, or chemotherapeutic agents.

[0160] The term "anticancer agent" or "antiproliferative agent" means any agent that can be used to treat a cell proliferative disorder such as cancer, and includes, but is not limited to, cytotoxic agents, cytostatic agents, anti-angiogenic agents, radiotherapy and radiotherapeutic agents, targeted anticancer agents, BRMs, therapeutic antibodies, cancer vaccines, cytokines, hormone therapy, radiotherapy, anti-metastatic agents, and immunotherapeutic agents. It should be understood that in selected embodiments as described above, such anticancer agents may comprise a conjugate and may be combined with the disclosed site-specific antibodies prior to administration. More specifically, in certain embodiments, the selected anticancer agent is linked to an unpaired cysteine ​​of an engineered antibody to provide an engineered conjugate as described herein. Therefore, such an engineered conjugate is explicitly contemplated within the scope of the present invention. In other embodiments, the disclosed anticancer agent will be administered in combination with a site-specific conjugate comprising a different therapeutic agent as described above.

[0161] diagnosis

[0162] The present invention provides in vitro and in vivo methods for detecting, diagnosing or monitoring proliferative disorders and methods for screening cells from patients to identify tumor cells including tumorigenic cells. Such methods include identifying individuals with cancer for treatment or monitoring the progression of cancer, including contacting the patient or a sample obtained from the patient (in vivo or in vitro) with an antibody as described herein, and detecting the presence or absence or binding level of the antibody bound to a bound or free target molecule in the sample. In some embodiments, the antibody will comprise a detectable label or reporter molecule as described herein.

[0163] In some aspects, the present disclosure provides a method for diagnosing, detecting or monitoring a disease associated with CD39 expression, comprising administering an effective dose of the antibody or antigen-binding fragment thereof, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, the multispecific molecule, or the pharmaceutical composition or kit to a subject in need thereof.

[0164] In some aspects, the present disclosure provides the antibody or antigen-binding fragment thereof, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, the multispecific molecule, or the pharmaceutical composition or kit for use in a method for diagnosing, detecting or monitoring a disease associated with CD39 expression in a subject.

[0165] In yet another aspect, the present disclosure provides use of the antibody or antigen-binding fragment thereof, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, the multispecific molecule, or the pharmaceutical composition or kit in the preparation of an agent (or drug) for diagnosing, detecting or monitoring a disease associated with CD39 expression.

[0166] Samples can be analyzed by a variety of assays, such as radioimmunoassays, enzyme immunoassays (e.g., ELISA), competitive binding assays, fluorescent immunoassays, immunoblotting assays, Western blot analysis, and flow cytometry assays. Compatible in vivo diagnostics or diagnostic assays can include imaging or monitoring techniques known in the art, such as magnetic resonance imaging, computerized tomography (e.g., CAT scans), positron emission tomography (e.g., PET scans), radiography, ultrasound, etc., known to those skilled in the art.

[0167] The method for detecting or monitoring CD39 expression or the level of cells expressing CD39 in vitro described in the present invention can also be used for non-diagnostic purposes.

[0168] Preferred subjects include mammals, such as humans / patients in need thereof.

[0169] The sample from the subject is blood, excreta (urine or feces), oral or nasal secretions, or alveolar lavage fluid, tissue fluid, sweat, or extracts thereof from the subject.

[0170] Pharmaceutical packaging and kits

[0171] Also provided are pharmaceutical packaging and kits containing one or more containers of one or more doses of an antibody or an antigen-binding fragment thereof. In certain embodiments, a unit dose is provided, wherein the unit dose contains a predetermined amount of a composition comprising, for example, an antibody or an antigen-binding fragment thereof, with or without one or more other agents. For other embodiments, such a unit dose is supplied in a disposable prefilled syringe for injection. In other embodiments, the composition contained in the unit dose may contain saline, sucrose or the like; a buffer such as phosphate, etc.; and / or be formulated in a stable and effective pH range. Alternatively, in certain embodiments, the conjugate composition may be provided as a lyophilized powder, which may be reconstituted after adding a suitable liquid (e.g., sterile water or saline). In certain preferred embodiments, the composition comprises one or more substances that inhibit protein aggregation, including but not limited to sucrose and arginine. Any label on or associated with the container indicates that the encapsulated conjugate composition is used to treat a selected tumor disease condition.

[0172] Such kits typically include a pharmaceutically acceptable formulation of the engineered conjugate in a suitable container, and optionally include one or more anticancer agents or other agents in the same or different containers. The kit may also contain other pharmaceutically acceptable formulations for diagnosis or combined therapy.

[0173] More specifically, the kit can have a single container containing an antibody or antigen-binding fragment thereof of the present disclosure, with or without additional components, or they can have different containers for each required reagent. In the case of providing a combination therapeutic agent for conjugation, a single solution can be premixed in a molar equivalent combination or one component more than another. Alternatively, the conjugate of the kit and any optional anticancer agent can be stored separately in different containers before being administered to a patient. The kit can also include a second / third container device for containing a sterile pharmaceutically acceptable buffer or other diluent such as bacteriostatic water for injection (BWFI), phosphate buffered saline (PBS), Ringer's solution, and glucose solution.

[0174] When the components of the kit are provided in one or more liquid solutions, the liquid solution is preferably an aqueous solution, particularly preferably a sterile aqueous solution or a saline solution. However, the components of the kit may be provided as dry powders. When the reagents or components are provided in dry powder form, the powder may be reconstituted by adding a suitable solvent. It is contemplated that the solvent may also be provided in another container.

[0175] Example

[0176] The invention generally described herein will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended to limit the invention. In addition, the experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials, reagent materials, etc. used in the following examples are commercially available products unless otherwise specified.

[0177] Example 1 Immunization and Generation and Screening of Hybridomas

[0178] In order to produce antibodies against CD39, Balb / c mice were immunized with recombinantly expressed Human CD39-ECD protein (purchased from ACRO, catalog number CD9-H52H4). During the immunization process, serum samples were obtained by bleeding from the tail vein or retroorbital to monitor the immune response. Mice with sufficient titers of anti-CD39 antibodies were used for hybridoma fusion experiments. Splenocytes and lymph node cells from immunized mice were isolated and fused with mouse myeloma cell lines (SP2 / 0). ELISA analysis was performed using HumanCD39-ECD recombinant protein, and binding analysis was performed using CHOZN-hCD39 cells (constructed by our company) that stably expressed human CD39 (BD FACSLyric TM), screen out hybridomas that can produce CD39-specific antibodies. The specificity of the hybridoma clones to Human CD39 was confirmed by FACS and enzyme activity inhibition experiments, and they were subcloned to obtain stable hybridoma clones. The hybridomas that secrete antibodies were subcloned by limiting dilution. After 1-2 rounds of subcloning, the monoclonal hybridomas were expanded to produce antibodies. Stable subclones were cultured in vitro to produce antibodies for characterization in tissue culture medium. After about 14 days of culture, the hybridoma cell culture medium was collected and purified by Protein A affinity chromatography column (GE). The screened hybridoma clone anti-CD39 antibody was named 19.4.

[0179]

[0180] SEQ ID NO:3 19.4 Heavy chain full length sequence

[0181] EVQLQQSGAELVRPGASVKLSCTASGFSFKNTYMHWMKQRPEQGLEWIGRIDPVNGNTKYAPKFQ

[0182] GKATITTDTSSNTAYLQLSSLTSEDTAVYFCARDYRFTYWGQGTLVTVSS

[0183] ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSS

[0184] VVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTL

[0185] MISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLN

[0186] GKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWE

[0187] SNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKSEQ ID NO:4 19.4 Full length light chain sequence

[0188] DIQMTQSPSSSLSASLGGKVTITCKASQDINKNIAWYQHKPGKGPRLLIWYTSTLQPGIPSRFSGSGSG

[0189] RDYSFSISNLEPEDIATYYCLQYDNLPYTFGSGTKLEIK

[0190] RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTY

[0191] SLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC

[0192] I394 is a reference antibody from patent WO2018167267A1, its VH is shown in SEQ ID NO:11, its VL is shown in SEQ ID NO:16, the heavy chain sequence is shown in SEQ ID NO:1, and the light chain sequence is shown in SEQ ID NO:2.

[0193] Example 2 Binding affinity to Human CD39 protein

[0194] Elisa was used to determine the ability of the antibody to bind to Human CD39 protein.

[0195] Human CD39 protein diluted with coating solution (0.05M carbonate, pH 9.6) was added to a 96-well plate, with a final concentration of 0.5μg / ml, 50μl per well, and coated overnight at 4°C; the plate was washed 3 times with PBST, and 5% skim milk powder was added for blocking for 1 hour; after washing with PBST, 50μl anti-CD39 antibody gradiently diluted with PBS (initial concentration 3.75μg / ml, 4-fold dilution, a total of 7 concentration gradient points) was added, and incubated at room temperature for 1 hour; after washing with PBST, 50μl 1:10000 diluted Goat Anti-Human IgG, Fcγ-HRP secondary antibody (purchased from Jackson ImmunoResearch, catalog number 109-035-170) was added, and incubated at room temperature for 1 hour; after washing with PBST, 50μl TMB was added, and incubated at room temperature for 5 minutes; the reaction was terminated by adding stop solution, and the absorbance value of OD450 was detected by an enzyme reader.

[0196] Example 3 Binding affinity to CHOZN-hCD39

[0197] FACS was used to determine antibody binding to a cell line expressing Human CD39 (CHOZN-hCD39), or cells lacking CD39 expression (CHOZN-blank) as a negative control.

[0198] CHOZN-hCD39 and CHOZN-blank cells were cultured in culture medium. The cells were collected and plated at 2×10 5 Resuspend the cells in blocking buffer at a density of cells / ml. Transfer the cells to a 96-well FACS plate at 50 μl / well, centrifuge the plate and wash twice with FACS buffer (PBS, 1% FBS, 0.05% Tween-20). Prepare 4-fold serial dilutions of anti-CD39 antibody with FACS buffer starting at 30 μg / ml. Use mouse IgG control as a negative control. Resuspend the cells in 50 μL / well of the diluted antibody and incubate the plate at 4°C for 30 minutes. Wash the plate with FACS buffer, add FITC (fluorescein isothiocyanate) labeled secondary antibody (1:1000 in FACS buffer) to each well and incubate at 4°C for 30 minutes. Wash the plate with FACS buffer and resuspend the cells in 50 μL / well of PBS. Then use BD FACSLyric TM Cells were analyzed and mean fluorescence intensity was determined. A complete binding curve for CD39 expressing cells was generated by testing a range of antibody concentrations. The apparent affinity of each antibody was calculated.

[0199] Example 4: Antibody protease inhibitory activity detection

[0200] The reaction solution (25 mM Tris, 5 mM MgCl 2 , pH 7.5) to dilute Human CD39 protein to 0.6μg / mL and add it to a 96-well plate (Greiner, catalog number 655209). The control well does not add protein, 30μL per well, and 30μL reaction solution is added; the anti-CD39 antibody to be tested is diluted with antibody diluent, starting at 30μg / ml, 4-fold gradient dilution, and a total of 7 concentration gradients are prepared. The gradient diluted antibody to be tested is added to a 96-well plate, 30μl per well. Incubate at 37℃ for 10min; dilute 10mM ATP (Sigma, catalog number: A7699-1G) to 150μM with reaction solution, 30μl per well is added to a 96-well plate, NC wells do not add ATP, and incubate at 37℃ for 30min; add 50μL CTG detection reagent (Promega, catalog number G7572) to each well, and detect the chemiluminescence value after incubation for 5min. Calculate the inhibition rate, inhibition rate = (RLU-RLU NC ) / (RLU Control -RLU NC)*100%.

[0201] Example 5 Hybridoma Sequencing

[0202] RNA was isolated from monoclonal hybridoma cells and reverse transcribed into cDNA using a commercial kit. The heavy and light chain variable regions were then amplified using cDNA as a template using primers from Mouse Ig-Primers. PCR products of the correct size were collected and purified and then ligated with a suitable plasmid vector. The ligated products were transformed into DH5α competent cells. Clones were screened and the inserts were analyzed by DNA sequencing.

[0203] Example 6 Production and Characterization of Chimeric Antibodies

[0204] 6.1 Production of chimeric antibodies

[0205] DNA encoding the variable regions of the four screened hybridoma antibodies (263.11, 383.16, 19.4, 105.1) was synthesized and subcloned into an expression vector containing a human IgG1 constant region gene. The vector was transfected into mammalian cells for recombinant protein expression, and the expressed chimeric antibody was purified using a Protein A affinity chromatography column.

[0206] 6.2 Characterization of chimeric antibodies

[0207] According to the methods described in Examples 2, 3, and 4, the binding ability and protease inhibitory activity of the chimeric antibody were tested.

[0208] The results showed that the binding affinities of the four anti-CD39 chimeric antibodies screened in this paper at the protein and cell levels were as follows: Figure 1 , Figure 2 As shown in Figure 2, all of them are better than the reference antibody I394. Figure 3 As shown, all four antibodies have good protease inhibitory activity, which is also better than the reference antibody I394.

[0209] Incorporated by Reference

[0210] Each patent document and scientific document mentioned herein is incorporated by reference in its entirety for all purposes.

[0211] Equivalence

[0212] The present invention may be embodied in other specific ways without departing from its spirit or essential characteristics. Therefore, the above embodiments should be regarded as illustrative in all cases, rather than limiting the invention described herein. Therefore, the scope of the present invention is indicated by the appended claims rather than by the above description, and it is intended that all changes within the equivalent meaning and scope of the claims are included therein.

Claims

1. An isolated antibody or antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment thereof specifically binds to CD39 and comprises a heavy chain variable region (VH) and a light chain variable region (VL), The heavy chain variable region and the light chain variable region include: HCDR1 shown in SEQ ID NO:21, HCDR2 shown in SEQ ID NO:25, and HCDR3 shown in SEQ ID NO:29, LCDR1 shown in SEQ ID NO:33, LCDR2 shown in SEQ ID NO:37, and LCDR3 shown in SEQ ID NO:

41.

2. The antibody or fragment according to claim 1, comprising: VH shown in SEQ ID NO:12, VL shown in SEQ ID NO:

17.

3. The antibody or fragment of claim 2, further comprising a heavy chain constant region and a light chain constant region, wherein the heavy chain constant region is selected from IgG1, IgG2, IgG3, or IgG4 constant region, and the light chain constant region is selected from κ or λ light chain constant region. The antibody or fragment according to claim 3 , wherein the heavy chain constant region is selected from the IgG1 constant region, and the light chain constant region is selected from the kappa chain constant region.

5. The antibody or fragment of claim 4, comprising: The heavy chain is shown in SEQ ID NO:3, and the light chain is shown in SEQ ID NO:

4.

6. The antibody or fragment according to claim 5, wherein the antibody is a whole antibody, a bispecific antibody, a monoclonal antibody, or a chimeric antibody.

7. The antibody or fragment of claim 6, wherein the antigen binding fragment is selected from the group consisting of a Fab fragment, a Fab' fragment, a F(ab)2 fragment, a Fv fragment and a ScFv.

8. The antibody or fragment of any one of the preceding claims, which inhibits soluble CD39 protease activity but does not inhibit the enzymatic activity of membrane-bound CD39.

9. An isolated nucleic acid molecule comprising a nucleic acid sequence encoding an antibody or fragment as described in any one of claims 1 to 8.

10. A vector comprising the nucleic acid molecule according to claim 9.

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