Antibody targeting CD105 or antigen-binding fragment thereof and use thereof

Abstract

The present invention belongs to the field of antibodies, and specifically relates to a CD105 binding molecule, particularly an antibody specifically recognizing CD105 and a fragment thereof. Furthermore, the present invention relates to a nucleic acid or host cell comprising such antibodies or fragments thereof, a drug comprising such antibodies or fragments thereof, and therapeutic and diagnostic methods or the use of applying the antibodies and fragments.

Description

An antibody targeting CD105 or its antigen-binding fragment and its application

[0001] This application is based on the Chinese patent application with application number 202311099001.1 and application date August 29, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0002] The present invention relates to the field of antibodies, and more specifically to a CD105 binding molecule, particularly an antibody and fragments thereof that specifically recognize CD105. Furthermore, the present invention relates to nucleic acids or host cells containing such antibodies or fragments thereof, medicaments containing such antibodies or fragments thereof, and therapeutic and diagnostic methods or uses utilizing such antibodies and fragments. Background Art

[0003] CD105, also known as endoglin, belongs to the transforming growth factor β (TGF-β) family of receptors and shares a high degree of homology with TβRIII. It binds to various TGF-β family cytokines, including TGF-β1, BMP7, BMP9, and Activin-A, and participates in physiological processes such as cell proliferation, migration, differentiation, and apoptosis. The CD105 gene is located on the long arm of human chromosome 9 at 9q34 and encodes 658 amino acids. Structurally, it comprises a 586-amino acid extracellular domain, a 22-amino acid transmembrane domain, and intracellular domains of varying lengths. CD105 forms a transmembrane glycoprotein homodimer linked by intermolecular disulfide bonds. Different splicing patterns of CD105 mRNA produce long and short variants, with the intracellular domains containing 41 and 14 amino acids, respectively, corresponding to dimeric protein molecular weights of 180 and 160 kDa. The long isoform is the predominantly expressed form of CD105.

[0004] CD105 is highly expressed in tumor endothelial cells and in tumor cells such as melanoma, renal cell carcinoma, leukemia, prostate cancer, breast cancer, and ovarian cancer. CD105 regulates the tumor microenvironment through the TGFβ / BMP pathway, promoting epithelial-mesenchymal transition (EMT), increasing spheroid formation, and enhancing tumor cell migration. Blocking CD105 function can induce tumor cell differentiation, reduce tumor stemness, and increase tumor cell sensitivity to conventional chemotherapeutic agents. In vivo studies have confirmed that CD105 is associated with tumor stemness and chemotherapy resistance. For example, CD105-positive tumor cells in renal cell carcinoma have been found to possess self-renewal capacity, leading to in vivo tumor stemness and resistance to gemcitabine-based chemotherapy drugs. In ovarian cancer, CD105 expression has been associated with drug resistance, poor differentiation, tumor stage, and recurrence. Inhibiting CD105 expression can reduce tumor invasiveness, induce tumor cell apoptosis, and increase sensitivity to carboplatin. In addition, in acute myeloid leukemia, high expression of CD105 often indicates a worse prognosis, including worse OS and PFS.

[0005] The tumor microenvironment plays a key role in tumor development and progression. In recent years, the role of CD105 in the tumor microenvironment has garnered increasing attention. CD105 is expressed on a variety of tumor microenvironment cells, including tumor vascular endothelial cells, mesenchymal stem cells (MSCs), cancer-associated fibroblasts (CAFs), and regulatory T cells (Tregs). CD105 is a cellular marker for MSCs, helping to maintain their stemness and homing properties. MSCs play a crucial role in the progression and metastasis of various tumors, and a high level of CD105+ MSCs often predicts faster tumor progression and a poorer prognosis. CAFs have been found to be highly expressed in various tumor tissues, including breast, lung, colorectal, and pancreatic cancers. Histologically, CAFs often surround tumor cells, promoting their growth, metastasis, and resistance to chemotherapeutic drugs. CD105 is also expressed on CAFs and plays a crucial role in their proliferation and activity.

[0006] Given that CD105 is widely expressed in tumor cells and the tumor microenvironment, it is of great significance to develop therapeutic drugs targeting this target. Carotuximab (TRC105) is the first and only CD105-specific blocking antibody that has entered the clinic. Its main mechanism is to inhibit tumor angiogenesis. Currently, TRC105 has been administered to patients with sarcoma, colorectal cancer, prostate cancer, renal cell carcinoma, lung cancer, breast cancer and ovarian cancer. Preliminary clinical results show that the drug is well tolerated and has no obvious side effects. At the same time, preliminary anti-tumor activity was observed in some patients, but the efficacy of antibodies alone is still weak. Antibody-drug conjugates (ADCs), as a new generation of therapeutic platforms, often have better efficacy against the same target.

[0007] Although certain anti-CD105 antibodies have been developed, there is still a need for further developing CD105 antibodies based on the existing technology, especially for developing anti-human CD105 antibodies with high specificity, high biological activity, high endocytosis ability, and / or that can be used to prepare immunoconjugates such as ADC or CAR-T.

[0008] Summary of the Invention

[0009] This study identified novel CD105-specific antibodies through screening of a fully human phage library. Furthermore, this application further conjugates these antibodies to obtain immunoconjugates, such as ADCs. The antibodies and conjugates based on these antibodies have demonstrated significant efficacy in a variety of tumor models and hold great promise for clinical application.

[0010] Therefore, in one aspect, the present invention discloses an antibody or antigen-binding fragment thereof that targets CD105 (eg, human or rhesus CD105).

[0011] The present invention therefore provides a novel antibody that binds to CD105, and an antigen-binding fragment thereof.

[0012] In some embodiments, the anti-CD105 antibodies of the invention have one or more or all of the following properties:

[0013] (1) capable of specifically binding to CD105 with high affinity, such as binding to human or rhesus CD105;

[0014] (2) can specifically bind to CD105 expressed on the cell membrane surface with high affinity, such as human or rhesus monkey CD105;

[0015] (3) being able to induce endocytosis of the antibody or its fragment or a molecule comprising the antibody or its fragment (e.g., an immunoconjugate such as ADC) by CD105-positive cells (e.g., CHO cells overexpressing CD105);

[0016] (4) Ability to target and kill CD105-positive cells, such as CD105-positive tumor cells;

[0017] (6) capable of treating tumors such as cancer, for example, treating CD105-positive tumors, such as CD105-positive cancers; or

[0018] (7) Suitable for constructing immunoconjugates (e.g., antibody-drug conjugates (ADCs)) for targeted killing of CD105-positive cells, such as CD105-positive tumor cells; or for treating tumors such as cancer, such as CD105-positive tumors, such as CD105-positive cancers.

[0019] In some embodiments, the present invention provides nucleic acids encoding the antibodies or fragments thereof of the present invention, vectors comprising the nucleic acids, and host cells comprising the vectors.

[0020] In some embodiments, the present invention provides methods of making an antibody or fragment thereof of the present invention.

[0021] In some embodiments, the present invention provides immunoconjugates, such as antibody drug conjugates, comprising an antibody of the present invention or a fragment thereof.

[0022] In some embodiments, the present invention provides pharmaceutical compositions and combination products comprising the antibodies or fragments thereof or immunoconjugates thereof of the present invention.

[0023] The present invention also provides methods for preventing or treating diseases, such as CD105-related diseases, such as tumors such as cancer (preferably CD105-positive tumors, such as CD105-positive cancers) in a subject using the antibodies of the present invention or their immunoconjugates.

[0024] The present invention also provides an antibody of the present invention or an immunoconjugate thereof for use in therapy, e.g., a method for preventing or treating a disease, e.g., a CD105-related disease, e.g., a tumor such as cancer (preferably a CD105-positive tumor, e.g., a CD105-positive cancer).

[0025] The present invention also provides uses of the antibodies or immunoconjugates thereof of the present invention, such as the preventive or therapeutic uses of the present invention and the use for preparing a medicament for preventing or treating the disease involved in the present invention.

[0026] The present invention also relates to a method for detecting CD105 in a sample.

[0027] The present invention also relates to methods and uses for diagnosing CD105-positive tumors, such as CD105-positive cancers. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 shows the flow cytometry results of CHO stable cell lines expressing human, rhesus monkey, and mouse CD105.

[0029] FIG2 shows the results of FACS detection of the binding of five antibodies and a control antibody to human and monkey CD105-overexpressing cells.

[0030] FIG3 shows the results of DT3C assay for the internalization of five antibodies and a control antibody into CHO cells expressing human CD105.

[0031] FIG4 shows the in vitro killing activity of ADCs obtained by coupling five antibodies and a control antibody to MMAE in 8305c ( FIG4A ) and MV4-11 ( FIG4B ).

[0032] FIG5 shows the in vivo activity of ADCs obtained by coupling five antibodies and a control antibody to MMAE in the MV4-11 CDX model.

[0033] FIG6 shows the in vivo activity of ADCs obtained by coupling four antibodies and a control antibody to MMAE in the 8305c CDX model.

[0034] Detailed Description of the Invention

[0035] For the purpose of explaining this specification, the following definitions will be used, and as long as appropriate, terms used in the singular may also include the plural, and vice versa. It should be understood that the present invention is not limited to the specific methodology, schemes and reagents described herein, as these may vary. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the scope of the present invention, which is limited only by the appended claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those of ordinary skill in the art to which the present invention belongs.

[0036] The term "about" when used in conjunction with a numerical value is meant to encompass the numerical value within a range having a lower limit that is 5% less than the specified numerical value and an upper limit that is 5% greater than the specified numerical value.

[0037] As used herein, the term "and / or" means any one of the alternatives or two or more of the alternatives.

[0038] As used herein, the terms "comprising" or "including" are intended to include the recited elements, integers, or steps, but do not exclude any other elements, integers, or steps. In this document, when the terms "comprising" or "including" are used, unless otherwise indicated, combinations of the recited elements, integers, or steps are also encompassed. For example, when reference is made to an antibody variable region "comprising" a specific sequence, it is intended to encompass an antibody variable region consisting of that specific sequence.

[0039] As used herein, the terms "anti," "binding," or "specific binding" mean that the binding is selective for the target or antigen and can be distinguished from unwanted or non-specific interactions. The ability of a binding site to bind to a specific target or antigen can be determined by flow cytometry or enzyme-linked immunosorbent assay (ELISA) or conventional binding assays known in the art, such as by radioimmunoassay (RIA) or thin-layer interferometry or MSD assays or surface plasmon resonance (SPR).

[0040] As used herein, the terms "anti-CD105 antibody," "anti-CD105," "CD105 antibody," or "CD105-binding antibody" refer to an antibody that binds to (primate, such as human or rhesus monkey) CD105 or a fragment thereof with sufficient affinity.

[0041] An "isolated" antibody or molecule is one that has been separated from a component of its natural environment. In some embodiments, the antibody or molecule is purified to greater than 95% or 99% purity, as determined by, for example, electrophoresis (e.g., SDS-PAGE, isoelectric focusing (IEF), capillary electrophoresis) or chromatography (e.g., ion exchange or reversed-phase HPLC).

[0042] The terms "whole antibody" or "full-length antibody" are used interchangeably herein and refer to antibody molecules with the structure of natural immunoglobulin molecules. In the case of conventional four-chain IgG antibodies, the full-length antibody comprises two heavy chains (H) and two light chains (L) interconnected by disulfide bonds. In the case of heavy chain antibodies having only heavy chains and lacking light chains, the full-length antibody comprises two heavy chains (H) interconnected by disulfide bonds. For conventional four-chain IgG antibodies, the full-length antibody heavy chain is generally composed of a heavy chain variable region (abbreviated herein as VH) and a heavy chain constant region, wherein the heavy chain constant region comprises at least three domains CH1, CH2 and CH3. The full-length antibody light chain is composed of a light chain variable region (abbreviated herein as VL) and a light chain constant region, wherein the light chain constant region consists of one domain CL. Each heavy chain variable region VH and each light chain variable region are composed of three CDRs and four FRs, arranged in the following order from amino terminus to carboxyl terminus: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. In some embodiments, the antibodies of the invention are full-length antibodies, such as conventional four-chain IgG full-length antibodies.

[0043] The term "antibody fragment" includes a portion of an intact antibody. In preferred embodiments, the antibody fragment is an antigen-binding fragment. The term "antigen-binding fragment" of an antibody refers to a molecule, distinct from a full-length antibody, that comprises a portion of a full-length antibody but is capable of binding to the antigen of the full-length antibody or competing with the full-length antibody (i.e., the full-length antibody from which the antigen-binding fragment is derived) for antigen binding. Antigen-binding fragments can be prepared by recombinant DNA techniques, or by enzymatic or chemical cleavage of intact antibodies. Antigen-binding fragments include, but are not limited to, Fv, Fab, Fab', Fab'-SH, F(ab')2, dAb (domain antibody), linear antibodies, single-chain antibodies (e.g., scFv); single-domain antibodies such as VHH, diabodies or fragments thereof, or camelid antibodies, diabodies, single-domain antibodies (sdAbs), or nanobodies. For example, Fab fragments can be obtained by papain digestion of a full-length antibody. In addition, digestion of a full-length antibody below the disulfide bonds in the hinge region by pepsin produces F(ab')2, a dimer of Fab', a divalent antibody fragment. F(ab')2 can be reduced under neutral conditions by breaking the disulfide bond in the hinge region, thereby converting the F(ab')2 dimer into a Fab' monomer. The Fv fragment consists of the VL and VH domains of a single antibody arm. The two domains of the Fv fragment, VL and VH, can be encoded by independent genes, but recombinant methods can also be used to connect the two domains using a synthetic linker peptide to produce them as a single protein chain, and in the single protein chain, the VL region and the VH region are paired to form a single-chain Fv (scFv).

[0044] "Complementarity determining region" or "CDR region" or "CDR" is a region in an antibody variable domain that is highly variable in sequence and forms structurally determined loops ("hypervariable loops") and / or contains antigen contact residues ("antigen contact points"). CDRs are primarily responsible for binding to antigenic epitopes. The CDRs of the heavy and light chains are typically referred to as CDR1, CDR2, and CDR3, and are numbered sequentially starting from the N-terminus. The CDRs located within the antibody heavy chain variable domain are referred to as HCDR1, HCDR2, and HCDR3, while the CDRs located within the antibody light chain variable domain are referred to as LCDR1, LCDR2, and LCDR3.In a given light chain variable region or heavy chain variable region amino acid sequence, the precise amino acid sequence boundaries of each CDR can be determined using any one or a combination of a number of well-known antibody CDR assignment schemes, including, for example, Chothia based on the three-dimensional structure of antibodies and the topology of the CDR loops (Chothia et al. (1989) Nature 342:877-883, Al-Lazikani et al., "Standard conformations for the canonical structures of immunoglobulins", Journal of Molecular Biology, 273, 927-948 (1997)), Kabat based on antibody sequence variability (Accessing the Kabat antibody sequence database by computer; Martin AC; Proteins, 1996; May;25(1):130-3;doi:10.1002 / (SICI)1097-0134(199605)25:1<130::AID-PROT11>3.0.CO;2-L.PMID:8727325), AbM (University of Bath), Contact (University College London), the international ImMunoGeneTics database (IMGT) (IMGT, the international ImMunoGeneTics information system, http: / / imgt.cines.fr; Lefranc MP; Novartis Found Symp. 2003;254:126-36; discussion 136-42,216-22,250-2.PMID:14712935Review), and the North CDR definition based on affinity propagation clustering using a large number of crystal structures.

[0045] In some embodiments, the CDRs of the heavy chain variable region of the antibodies of the present invention are determined according to Kabat or IMGT. In some embodiments, the CDRs of the light chain variable region of the antibodies of the present invention are determined according to Kabat or IMGT. In some embodiments, the CDRs of the heavy chain variable region and the light chain variable region of the antibodies of the present invention are determined according to Kabat or IMGT.

[0046] Unless otherwise indicated herein, amino acid residue numbering in the Fc or heavy chain constant region is according to the EU numbering system (also called the EU index) as described in Kabat et al., Sequences of Proteins of Immunological Interes, 5th Ed., Public Health Service, National Institutes of Health, Bethesda, MD, 1991, NIH Publication 91-3242; amino acid residue numbering in the light and heavy chain variable regions is according to the Kabat numbering system (also called the Kabat index) as described in Kabat et al., Sequences of Proteins of Immunological Interes, 5th Ed., Public Health Service, National Institutes of Health, Bethesda, MD, 1991, NIH Publication 91-3242.

[0047] The term "amino acid substitution" is used interchangeably herein and refers to the replacement of at least one amino acid residue in a predetermined parent amino acid sequence with a different "substituted" amino acid residue. The replacement residue or residues can be a "naturally occurring amino acid residue" (i.e., encoded by the genetic code) and are selected from the group consisting of: alanine (Ala); arginine (Arg); asparagine (Asn); aspartic acid (Asp); cysteine ​​(Cys); glutamine (Gln); glutamic acid (Glu); glycine (Gly); histidine (His); isoleucine (Ile); leucine (Leu); lysine (Lys); methionine (Met); phenylalanine (Phe); proline (Pro); serine (Ser); threonine (Thr); tryptophan (Trp); tyrosine (Tyr); and valine (Val). The definition of amino acid substitution herein also encompasses substitution with one or more non-naturally occurring amino acid residues. "Non-natural amino acid residues" refer to residues that are capable of covalently binding to adjacent amino acid residues in a polypeptide chain, in addition to those naturally occurring amino acid residues listed above. Examples of non-natural amino acid residues include norleucine, ornithine, norvaline, homoserine, Aib and other amino acid residue analogs.

[0048] As used herein, "conservative changes" include substitutions, deletions, or additions to a polypeptide sequence that do not substantially alter the desired functional activity of the polypeptide sequence. In some embodiments, conservative changes are conservative substitutions. Conservative substitutions refer to the replacement of one amino acid with another amino acid within the same class, such as the replacement of an acidic amino acid with another acidic amino acid, the replacement of a basic amino acid with another basic amino acid, or the replacement of a neutral amino acid with another neutral amino acid. For example, conservative substitutions often result in the replacement of an amino acid with a chemically similar amino acid. Conservative substitution tables providing functionally similar amino acids are well known in the art. The following lists 8 groups of amino acids containing conservative substitutions for each other: 1) Alanine (A), Glycine (G); 2) Aspartic acid (D), Glutamic acid (E); 3) Asparagine (N), Glutamine (Q); 4) Arginine (R), Lysine (K); 5) Isoleucine (I), Leucine (L), Methionine (M), Valine (V); 6) Phenylalanine (F), Tyrosine (Y), Tryptophan (W); 7) Serine (S), Threonine (T); and 8) Cysteine ​​(C), Methionine (M). In some embodiments, the term "conservative change" when applied to an antibody molecule amino acid sequence refers to an amino acid modification that does not significantly affect or change the target antigen binding characteristics of the antibody molecule of the present invention containing the amino acid sequence. For example, a conservatively changed variant maintains at least 80%, 85%, 90%, 95%, 98%, 99% or higher, such as 100-110% or higher, binding affinity for the target antigen relative to the parent antibody.

[0049] The term "therapeutic agent" as used herein encompasses any substance effective in preventing or treating tumors, such as cancer, including chemotherapeutic agents, cytokines, cytotoxic agents, other antibodies, small molecule drugs, or immunomodulators (such as immunosuppressants or immune activators).

[0050] "Chemotherapeutic agents" include chemical compounds useful in treating cancer or immune system disorders.

[0051] The term "small molecule drug" refers to low molecular weight organic compounds that are capable of regulating biological processes. "Small molecules" are defined as molecules with a molecular weight of less than 10 kD, typically less than 2 kD, and preferably less than 10 kD. Small molecules include, but are not limited to, inorganic molecules, organic molecules, organic molecules containing inorganic components, molecules containing radioactive atoms, synthetic molecules, peptide mimetics, and antibody mimics. As therapeutic agents, small molecules can be more cell-permeable, less susceptible to degradation, and less prone to eliciting an immune response than macromolecules.

[0052] As used herein, the term "immunomodulator" refers to a natural or synthetic agent or drug that inhibits or modulates an immune response. The immune response can be a humoral response or a cellular response. Immunomodulators include immunosuppressants. In some embodiments, the immunomodulators of the present invention include immune checkpoint inhibitors or immune checkpoint agonists.

[0053] "Isolated nucleic acid encoding an anti-CD105 antibody or fragment thereof" refers to one or more nucleic acid molecules encoding an antibody heavy chain or light chain (or fragment thereof, such as a heavy chain variable region or a light chain variable region), including such nucleic acid molecules in a single vector or separate vectors, and such nucleic acid molecules present at one or more locations in a host cell.

[0054] "Percent identity (%)" of an amino acid sequence refers to the percentage of amino acid residues in the candidate sequence that are identical to the amino acid residues in the specific amino acid sequence set forth in this specification, after aligning the candidate sequence with the specific amino acid sequence set forth in this specification and introducing gaps, if necessary, to achieve the maximum percentage identity, and not considering any conservative substitutions as part of the sequence identity. In some embodiments, the present invention contemplates variants of the antibody molecules of the present invention that have a substantial degree of identity, e.g., at least 80%, 85%, 90%, 95%, 97%, 98% or 99% or more, relative to the antibody molecules and sequences thereof specifically disclosed herein. Such variants may comprise conservative changes.

[0055] The term "pharmaceutical excipient" refers to a diluent, adjuvant (eg, Freund's adjuvant (complete and incomplete)), excipient, carrier, stabilizer, or the like, which is administered together with the active substance.

[0056] The term "label" as used herein refers to a compound or composition that is directly or indirectly conjugated or fused to a reagent (such as a polynucleotide probe or antibody) and promotes the detection of the reagent to which it is conjugated or fused. The label itself can be detectable (e.g., a radioisotope label or a fluorescent label) or can catalyze a chemical change in a detectable substrate compound or composition in the case of an enzymatic label. The term is intended to encompass direct labeling of a probe or antibody by coupling (i.e., physically connecting) a detectable substance to the probe or antibody and indirect labeling of the probe or antibody by reacting with another reagent of the direct label.

[0057] The term "combination therapy" refers to the administration of two or more therapeutic agents or treatment modalities to treat diseases described herein. This administration includes co-administering these therapeutic agents in a substantially simultaneous manner, such as in a single capsule with a fixed ratio of active ingredients. Alternatively, this administration includes co-administration of each active ingredient in a variety of or separate containers (such as tablets, capsules, powders, and liquids). The powder and / or liquid can be reconstituted or diluted to the desired dose before administration. In addition, this administration also includes using each type of therapeutic agent in a sequential manner at approximately the same time or at different times. In either case, the therapeutic regimen will provide the beneficial effects of the drug combination in treating disorders or conditions described herein.

[0058] As used herein, "treat," ...

[0059] As used herein, "prevention" includes the inhibition of the onset or development of a disease or condition or symptoms of a particular disease or condition.

[0060] "Subject / patient / individual sample" refers to a collection of cells or fluids obtained from a patient or subject. The source of a tissue or cell sample can be solid tissue, such as a sample from a fresh, frozen and / or preserved organ or tissue sample or a biopsy sample or a puncture sample; blood or any blood component; body fluids, such as tears, vitreous humor, cerebrospinal fluid, amniotic fluid (amniotic fluid), peritoneal fluid (ascites), or interstitial fluid; cells from any time during the subject's pregnancy or development. Tissue samples may contain compounds that are not naturally contaminated with tissue in nature, such as preservatives, anticoagulants, buffers, fixatives, nutrients, antibiotics, etc.

[0061] A first aspect of the present invention provides an antibody or a fragment thereof (eg, an antigen-binding fragment) that specifically binds to CD105.

[0062] In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention comprise three complementarity determining regions (HCDRs) from the heavy chain variable region, HCDR1, HCDR2, and HCDR3. In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention comprise three complementarity determining regions (LCDRs) from the light chain variable region, LCDR1, LCDR2, and LCDR3. In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention comprise three complementarity determining regions (HCDRs) from the heavy chain variable region and three complementarity determining regions (LCDRs) from the light chain variable region.

[0063] In some aspects, the anti-CD105 antibodies of the present invention or its antigen-binding fragment include a heavy chain variable region (VH). In some aspects, the anti-CD105 antibodies of the present invention or its antigen-binding fragment include a light chain variable region (VL). In some aspects, the anti-CD105 antibodies of the present invention or its antigen-binding fragment include a heavy chain variable region (VH) and a light chain variable region (VL). In some embodiments, the heavy chain variable region includes 3 complementary determining regions (HCDRs) from the heavy chain variable region, HCDR1, HCDR2 and HCDR3. In some embodiments, the light chain variable region includes 3 complementary determining regions (LCDRs) from the light chain variable region, LCDR1, LCDR2 and LCDR3.

[0064] In some embodiments, the heavy chain variable region of the invention

[0065] (i) comprises or consists of an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 1, 15, 29, 41 or 50; or

[0066] (ii) comprises or consists of an amino acid sequence selected from SEQ ID NO: 1, 15, 29, 41 or 50; or

[0067] (iii) comprises or consists of an amino acid sequence having one or more (preferably no more than 10, more preferably no more than 5, 4, 3, 2, 1) amino acid changes (e.g., conservative changes, such as amino acid substitutions, more preferably conservative amino acid substitutions) compared to an amino acid sequence selected from SEQ ID NO: 1, 15, 29, 41 or 50, preferably, the amino acid changes do not occur in the CDR regions.

[0068] In some embodiments, the light chain variable region of the present invention

[0069] (i) comprises or consists of an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 2, 16, 30, 42 or 51; or

[0070] (ii) comprises or consists of an amino acid sequence selected from SEQ ID NO: 2, 16, 30, 42 or 51; or

[0071] (iii) comprises or consists of an amino acid sequence having one or more (preferably no more than 10, more preferably no more than 5, 4, 3, 2, 1) amino acid changes (e.g., conservative changes, such as amino acid substitutions, more preferably conservative amino acid substitutions) compared to an amino acid sequence selected from SEQ ID NO: 2, 16, 30, 42 or 51, preferably, the amino acid changes do not occur in the CDR regions.

[0072] In some embodiments, the three complementarity determining regions (HCDRs) of the present invention, HCDR1, HCDR2, and HCDR3, from the heavy chain variable region are selected from

[0073] (i) three complementarity determining regions HCDR1, HCDR2 and HCDR3 contained in VH as shown in SEQ ID NO: 1, 15, 29, 41 or 50, or

[0074] (ii) a sequence comprising at least one and no more than 5, 4, 3, 2 or 1 amino acid change (preferably an amino acid substitution, preferably a conservative substitution) in the three HCDR regions relative to the sequence of any one of (i),

[0075] wherein the HCDRs can be determined according to any CDR assignment scheme, such as the assignment schemes of Kabat, AbM, Chothia or IMGT, or a combination thereof, respectively,

[0076] For example, the HCDRs are defined according to IMGT or Kabat, respectively.

[0077] In some embodiments, the three complementarity determining regions (LCDRs) of the present invention, LCDR1, LCDR2, and LCDR3, from the light chain variable region are selected from

[0078] (i) three complementary determining regions LCDR1, LCDR2 and LCDR3 contained in the VL as shown in SEQ ID NO: 2, 16, 30, 42 or 51,

[0079] or

[0080] (ii) a sequence comprising at least one and no more than 5, 4, 3, 2 or 1 amino acid alteration (preferably an amino acid substitution, preferably a conservative substitution) in the three LCDR regions relative to the sequence of any one of (i),

[0081] wherein the LCDRs can be determined according to any CDR assignment scheme, such as the assignment schemes of Kabat, AbM, Chothia or IMGT, or a combination thereof, respectively,

[0082] For example, the LCDR is determined according to IMGT or Kabat, respectively.

[0083] In some embodiments, the HCDR1 determined based on IMGT comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 3, 17, or 52, or the HCDR1 determined based on IMGT comprises an amino acid sequence having one, two, or three changes (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 3, 17, or 52.

[0084] In some embodiments, the HCDR1 determined based on Kabat comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 9, 23, 36, or 58, or the HCDR1 determined based on Kabat comprises an amino acid sequence having one, two, or three changes (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 9, 23, 36, or 58.

[0085] In some embodiments, the HCDR2 determined based on IMGT comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 4, 18, 31, or 53, or the HCDR2 determined based on IMGT comprises an amino acid sequence having one, two, or three alterations (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 4, 18, 31, or 53.

[0086] In some embodiments, the HCDR2 determined based on Kabat comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 10, 24, 37, or 59, or the HCDR2 determined based on Kabat comprises an amino acid sequence having one, two, or three changes (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 10, 24, 37, or 59.

[0087] In some embodiments, the HCDR3 determined based on IMGT comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 5, 19, 32, 43, or 54, or the HCDR3 determined based on IMGT comprises an amino acid sequence having one, two, or three alterations (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 5, 19, 32, 43, or 54.

[0088] In some embodiments, the HCDR3 determined based on Kabat comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 11, 25, 38, 47, or 60, or the HCDR3 determined based on Kabat comprises an amino acid sequence having one, two, or three changes (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 11, 25, 38, 47, or 60.

[0089] In some embodiments, LCDR1 determined based on IMGT comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 6, 20, 33, 44, or 55, or LCDR1 determined based on IMGT comprises an amino acid sequence having one, two, or three changes (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 6, 20, 33, 44, or 55.

[0090] In some embodiments, LCDR1 determined based on Kabat comprises the amino acid sequence shown in any one of SEQ ID NO: 12, 26, 39, 48 or 61, or consists of the amino acid sequence, or LCDR1 determined based on Kabat comprises an amino acid sequence having one, two or three changes (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NO: 12, 26, 39, 48 or 61.

[0091] In some embodiments, the LCDR2 determined based on IMGT comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 7, 21, 34, 45, or 56, or the LCDR2 determined based on IMGT comprises an amino acid sequence having one, two, or three alterations (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 7, 21, 34, 45, or 56.

[0092] In some embodiments, LCDR2 determined based on Kabat comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 13, 27, 40, 49, or 62, or LCDR2 determined based on Kabat comprises an amino acid sequence having one, two, or three changes (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 13, 27, 40, 49, or 62.

[0093] In some embodiments, the LCDR3 determined based on IMGT comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 8, 22, 35, 46, or 57, or the LCDR3 determined based on IMGT comprises an amino acid sequence having one, two, or three alterations (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 8, 22, 35, 46, or 57.

[0094] In some embodiments, the LCDR3 determined based on Kabat comprises or consists of the amino acid sequence shown in any one of SEQ ID NOs: 8, 22, 35, 46, or 57, or the LCDR3 determined based on Kabat comprises an amino acid sequence having one, two, or three changes (preferably amino acid substitutions, preferably conservative substitutions) compared to the amino acid sequence shown in any one of SEQ ID NOs: 8, 22, 35, 46, or 57.

[0095] In some embodiments of the present invention, the anti-CD105 antibody or antigen-binding fragment thereof comprises:

[0096] 1) the three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO: 1, and the three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO: 2;

[0097] 2) three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO: 15, and three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO: 16;

[0098] 3) three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO: 29, and three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO: 30;

[0099] 4) the three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO:41, and the three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO:42; or

[0100] 5) the three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO: 50, and the three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO: 51,

[0101] For example, the HCDR and the LCDR are respectively determined according to the IMGT scheme, or respectively determined according to the Kabat scheme.

[0102] In some specific embodiments of the present invention, the anti-CD105 antibody or antigen-binding fragment thereof of the present invention comprises: three complementarity determining regions HCDR1, HCDR2, and HCDR3 of the heavy chain variable region, and three complementarity determining regions LCDR1, LCDR2, and LCDR3 of the light chain variable region, wherein the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3 respectively comprise or consist of the amino acid sequence shown in the following table SEQ ID NO based on the IMGT scheme:

[0103] Or wherein the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are based on the Kabat scheme, and each comprises or consists of the amino acid sequence shown in the following table SEQ ID NO:

[0104] In some specific embodiments of the present invention, the anti-CD105 antibody or antigen-binding fragment thereof comprises VH and VL, wherein VH and VL respectively comprise the amino acid sequence as set forth in the following SEQ ID NO, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence as set forth in the following SEQ ID NO, or consist of the amino acid sequence:

[0105] In a preferred embodiment, the present invention provides an anti-CD105 antibody or an antigen-binding fragment thereof, comprising a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region and the light chain variable region respectively comprise or consist of the amino acid sequence shown in the following table SEQ ID NO:

[0106] In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention further comprise an antibody heavy chain constant region. In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention further comprise an antibody light chain constant region. In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention further comprise a heavy chain constant region and a light chain constant region.

[0107] In some embodiments, the heavy chain constant region of the antibody of the present invention is the heavy chain constant region of IgG1, IgG2, IgG3 or IgG4, preferably the heavy chain constant region of IgG1. In some embodiments, the light chain constant region of the antibody of the present invention is the light chain constant region of λ or Kappa.

[0108] In some preferred embodiments, the heavy chain constant region of the antibody of the present invention is

[0109] (i) comprising or consisting of an amino acid sequence that is at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 66;

[0110] (ii) comprises or consists of the amino acid sequence of SEQ ID NO: 66; or

[0111] (iii) comprises or consists of an amino acid sequence having one or more (preferably no more than 20 or 10, more preferably no more than 5, 4, 3, 2, or 1) amino acid changes (e.g., conservative changes, such as amino acid substitutions, more preferably conservative amino acid substitutions) compared to the amino acid sequence of SEQ ID NO: 66.

[0112] In some embodiments, the antibody light chain constant region of the invention is

[0113] (i) comprising or consisting of an amino acid sequence that is at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 67 or 68;

[0114] (ii) comprises or consists of an amino acid sequence selected from SEQ ID NO: 67 or 68; or

[0115] (iii) comprises or consists of an amino acid sequence having one or more (preferably no more than 20 or 10, more preferably no more than 5, 4, 3, 2, or 1) amino acid changes (e.g., conservative changes, such as amino acid substitutions, more preferably conservative amino acid substitutions) compared to an amino acid sequence selected from SEQ ID NO: 67 or 68.

[0116] In some embodiments, the antibodies or fragments thereof of the present invention comprise a heavy chain constant region and a light chain constant region, wherein the heavy chain constant region comprises, or consists of, the amino acid sequence shown in SEQ ID NO: 66, and the light chain constant region comprises, or consists of, the amino acid sequence shown in SEQ ID NO: 67 or 68.

[0117] In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention comprise an antibody heavy chain (HC). In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention further comprise an antibody light chain (LC). In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention comprise a heavy chain and a light chain.

[0118] In some embodiments, the antibody heavy chain of the present invention comprises an antibody heavy chain variable region and an antibody heavy chain constant region or consists of an antibody heavy chain variable region and an antibody heavy chain constant region. In some embodiments, the antibody light chain of the present invention comprises an antibody light chain variable region and an antibody light chain constant region or consists of an antibody light chain variable region and an antibody light chain constant region. In some embodiments, the antibody of the present invention comprises two heavy chains and two light chains, or consists of two heavy chains and two light chains, for example, the two heavy chains are identical and the two light chains are identical.

[0119] In some embodiments, the antibodies of the present invention comprise a heavy chain and a light chain, wherein the heavy chain comprises a heavy chain variable region and a heavy chain constant region or consists of a heavy chain variable region and a light chain variable region, and the light chain comprises a light chain variable region and a light chain constant region or consists of a heavy chain variable region and a light chain variable region, wherein

[0120] (i) the heavy chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 1, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the light chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 2, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the heavy chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 66, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, and the light chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: The amino acid sequence of NO:67, or an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, or consisting of said amino acid sequence;

[0121] (ii) the heavy chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 15, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the light chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 16, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the heavy chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 66, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, and the light chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: The amino acid sequence of NO:68, or an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, or consisting of said amino acid sequence;

[0122] (iii) the heavy chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 29, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the light chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 30, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the heavy chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 66, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, and the light chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: The amino acid sequence of NO:68, or an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, or consisting of said amino acid sequence;

[0123] (iv) the heavy chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 41, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the light chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 42, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the heavy chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 66, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, and the light chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: The amino acid sequence of NO:68, or an amino acid sequence at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, or consisting of said amino acid sequence; or

[0124] (v) the heavy chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 50, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the light chain variable region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 51, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, the heavy chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: 66, or an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical thereto, and the light chain constant region comprises or consists of an amino acid sequence as set forth in SEQ ID NO: The amino acid sequence shown in NO:68, or an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identity thereto, or consisting of said amino acid sequence.

[0125] In some embodiments, the antibodies of the present invention comprise a heavy chain and a light chain, wherein the heavy chain comprises a heavy chain variable region and a heavy chain constant region or consists of a heavy chain variable region and a light chain variable region, and the light chain comprises a light chain variable region and a light chain constant region or consists of a heavy chain variable region and a light chain variable region, wherein

[0126] (i) the heavy chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 1, the light chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 2, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 67;

[0127] (ii) the heavy chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 15, the light chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 16, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 68;

[0128] (iii) the heavy chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 29, the light chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 30, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 68;

[0129] (iv) the heavy chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 41, the light chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 42, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 68; or

[0130] (v) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 50, the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 51, the heavy chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 68.

[0131] In one embodiment of the invention, the amino acid changes described herein are conservative changes. In one embodiment of the invention, the amino acid changes described herein include amino acid substitutions, insertions or deletions or a combination thereof. Preferably, the amino acid changes described herein are amino acid substitutions, preferably conservative substitutions.

[0132] In a preferred embodiment, the amino acid changes described herein occur in regions outside the CDRs (e.g., in the FRs). More preferably, the amino acid changes described herein occur in regions outside the heavy chain variable region and / or outside the light chain variable region (e.g., heavy chain constant region or light chain constant region).

[0133] In some embodiments, the substitution is a conservative substitution. A conservative substitution refers to the substitution of one amino acid by another amino acid within the same class, such as an acidic amino acid by another acidic amino acid, a basic amino acid by another basic amino acid, or a neutral amino acid by another neutral amino acid.

[0134] In certain embodiments, substitution occurs in the CDR regions of an antibody. Typically, the variants obtained have modifications (e.g., improvements) relative to certain biological properties of the parent antibody (e.g., increased affinity) and / or will have certain biological properties that are substantially retained of the parent antibody.

[0135] In certain embodiments, it may be desirable to generate cysteine ​​engineered antibodies, eg, "thioMAbs," in which one or more residues of an antibody are substituted with cysteine ​​residues.

[0136] In certain embodiments, the antibodies provided herein may be further modified to contain other non-proteinaceous moieties known in the art and readily available. Suitable moieties for antibody derivatization include, but are not limited to, water-soluble polymers. Non-limiting examples of water-soluble polymers include, but are not limited to, polyethylene glycol (PEG), ethylene glycol / propylene glycol copolymers, carboxymethyl cellulose, dextran, polyvinyl alcohol, polyvinyl pyrrolidone, poly-1,3-dioxane, poly-1,3,6-trioxane, ethylene / maleic anhydride copolymers, polyamino acids (homopolymers or random copolymers), and dextran or poly (n-vinyl pyrrolidone) polyethylene glycol, propylene glycol homopolymers, polypropylene oxide / ethylene oxide copolymers, polyoxyethylated polyols (e.g., glycerol), polyvinyl alcohol, and mixtures thereof.

[0137] In some embodiments, the anti-CD105 antibodies or antigen-binding fragments thereof of the present invention further include antibodies or antigen-binding fragments having one or more of the following properties:

[0138] (1) exhibiting the same or similar binding affinity and / or specificity for CD105 as any of the antibodies listed in the present invention, such as the antibodies prepared in the Examples;

[0139] (2) inhibiting the binding of any antibody listed in the present invention, such as the antibody prepared in the Examples, to CD105;

[0140] (3) binds to the same or overlapping epitope as any of the antibodies described herein, such as the antibodies prepared in the Examples; or

[0141] (4) Compete with any antibody of the present invention, such as the antibody prepared in the Examples, for binding to CD105.

[0142] As defined herein, an "antibody that binds to the same or overlapping epitope as a reference antibody" is an antibody that blocks 50%, 60%, 70%, 80%, 90% or 95% or more of the binding of the reference antibody to its antigen in a competition assay, whereas conversely, the reference antibody blocks 50%, 60%, 70%, 80%, 90% or 95% or more of the binding of the antibody to its antigen in a competition assay.

[0143] As defined herein, an antibody that competes with a reference antibody for binding to its antigen is an antibody that blocks 50%, 60%, 70%, 80%, 90%, or 95% or more of the binding of the reference antibody to its antigen in a competition assay. Conversely, a reference antibody blocks 50%, 60%, 70%, 80%, 90%, or 95% or more of the binding of the antibody to its antigen in a competition assay. Numerous types of competitive binding assays can be used to determine whether one antibody competes with another, such as solid phase direct or indirect radioimmunoassays (RIAs), solid phase direct or indirect enzyme immunoassays (EIAs), sandwich competition assays, biointerferometry (e.g., Fortebio), or surface plasmon resonance (Biacore).

[0144] As defined herein, an antibody that inhibits (e.g., competitively inhibits) the binding of a reference antibody to its antigen is an antibody that inhibits the binding of the reference antibody to its antigen by 50%, 60%, 70%, 80%, 90%, or 95% or more. Conversely, a reference antibody inhibits the binding of the antibody to its antigen by 50%, 60%, 70%, 80%, 90%, or 95% or more. The binding of an antibody to its antigen can be measured by affinity (e.g., equilibrium dissociation constant). Methods for determining affinity are known in the art.

[0145] An antibody that exhibits the same or similar binding affinity and / or specificity as a reference antibody is an antibody that has at least 50%, 60%, 70%, 80%, 90% or more than 95% of the binding affinity and / or specificity of the reference antibody. This can be determined by any method known in the art for determining binding affinity and / or specificity.

[0146] In some embodiments, the anti-CD105 antibody is a monoclonal antibody.

[0147] In some embodiments, the anti-CD105 antibody is a human antibody.

[0148] In some embodiments, the anti-CD105 antibody is a full-length antibody.

[0149] In one embodiment, the anti-CD105 antibodies of the present invention also encompass antibody fragments thereof such as antigen-binding fragments thereof. In some embodiments, the antibody fragments include but are not limited to Fab, Fab', F(ab')2, Fv, single-chain Fv, diabody, single-domain antibody (sdAb), nanobody or sc(Fv)2.

[0150] In certain embodiments, the anti-CD105 antibody molecule is in the form of a bispecific or multispecific antibody molecule. In one embodiment, the bispecific antibody can bind to two different epitopes of the CD105 protein. In one embodiment, the bispecific antibody can bind to CD105 and another protein such as an antigen. Therefore, the anti-CD105 antibodies of the present invention also encompass multispecific antibodies such as bispecific antibodies that specifically bind to CD105 and other antigens.

[0151] Thus, in some embodiments, the present invention relates to a bispecific antibody or multispecific antibody that specifically binds to CD105 and one or more other antigens.

[0152] The second aspect of the present invention is to provide an immunoconjugate comprising the anti-CD105 antibody or antigen-binding fragment thereof of the present invention.

[0153] In some embodiments, the immunoconjugate is an antibody drug conjugate (ADC).

[0154] The antibodies or fragments thereof of the present invention can induce endocytosis of the antibodies or fragments thereof or molecules comprising the antibodies or fragments thereof by CD105-positive cells (eg, CD105-positive tumor cells), and are therefore suitable for use in constructing antibody-drug conjugates.

[0155] In some embodiments, the present invention provides immunoconjugates, such as antibody drug conjugates (ADCs), comprising any anti-CD105 antibody provided herein and other substances, such as therapeutic agents or labels. In some embodiments, the therapeutic agent is a cytotoxic agent. In some embodiments, the therapeutic agent is MMAE.

[0156] In some embodiments, an antibody or antigen-binding fragment thereof of the present invention is linked to another substance, such as a cytotoxic agent (e.g., MMAE), via a linker to form an antibody-drug conjugate. In some embodiments, the linker is a Vc linker. In some embodiments, an antibody or antigen-binding fragment thereof of the present invention is linked to VcMMAE to form an antibody-drug conjugate.

[0157] In a third aspect of the present invention, a nucleic acid, such as an isolated nucleic acid molecule, encoding an anti-CD105 antibody or fragment thereof or either chain thereof is provided.

[0158] For example, nucleic acids of the invention include nucleic acids encoding an amino acid sequence selected from any one of SEQ ID NOs: 1, 2, 15, 16, 29, 30, 41, 42, 50, or 51, or nucleic acids encoding an amino acid sequence that is at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to an amino acid sequence selected from any one of SEQ ID NOs: 1, 2, 15, 16, 29, 30, 41, 42, 50, or 51. As will be appreciated by those skilled in the art, due to codon degeneracy, each antibody or polypeptide amino acid sequence can be encoded by multiple nucleic acid sequences. Nucleic acid sequences encoding molecules of the invention can be generated using methods well known in the art, such as de novo solid phase DNA synthesis or PCR amplification.

[0159] When expressed from a suitable expression vector, the polypeptide encoded by the nucleic acid can show human (and / or rhesus monkey) CD105 antigen binding ability. For example, in some embodiments, the nucleic acid encoding the heavy chain variable region and / or light chain variable region is operably connected in frame with the nucleic acid encoding the heavy chain constant region and / or light chain constant region, so that when expressed from a suitable expression vector, the nucleic acid encoding the antibody heavy chain and / or light chain constant region is produced.

[0160] To facilitate production and purification, a secretory signal peptide and / or a tag peptide that facilitates purification, such as a his tag, can be fused to the N-terminus of the heavy chain and / or light chain of the antibody.

[0161] In a fourth aspect of the present invention, one or more vectors comprising the nucleic acid of the present invention are provided.

[0162] In one embodiment, the vector is an expression vector, such as a eukaryotic expression vector. Vectors include but are not limited to viruses, plasmids, cosmids, lambda phages, or yeast artificial chromosomes (YACs). In one embodiment, the vector is a pCDNA vector, such as pCDNA3.4.

[0163] As used herein, the term "vector" refers to a nucleic acid molecule capable of propagating another nucleic acid to which it is attached. The term includes vectors that are self-replicating nucleic acid structures as well as vectors that are incorporated into the genome of a host cell into which it has been introduced. The term "expression vector" refers to a vector comprising a recombinant polynucleotide comprising an expression control sequence that is operatively linked to the nucleotide sequence to be expressed. The expression vector comprises sufficient cis-acting elements for expression; other elements for expression can be provided by the host cell or in an in vitro expression system. Expression vectors include all those known in the art, including cosmids, plasmids (e.g., naked or contained in liposomes), and viruses (e.g., lentiviruses, retroviruses, adenoviruses, and adeno-associated viruses) that are incorporated into recombinant polynucleotides.

[0164] In a fifth aspect of the present invention, a host cell comprising a nucleic acid encoding the antibody or antigen-binding fragment thereof of the present invention, or a vector comprising the nucleic acid is provided.

[0165] The term "host cell" refers to a cell into which an exogenous polynucleotide has been introduced, including the progeny of such cells. Host cells include "transformants" and "transformed cells", which include primary transformed cells and progeny derived therefrom, without considering the number of passages. Progeny may not be completely identical to the parent cell in nucleic acid content, but may contain mutations. Included herein are mutant progeny with the same function or biological activity that have been screened or selected in the initially transformed cells. Host cells are any type of cell system that can be used to produce the antibody molecules of the present invention, including eukaryotic cells, for example, mammalian cells, insect cells, yeast cells; and prokaryotic cells, for example, Escherichia coli cells. Host cells include cultured cells, as well as cells within transgenic animals, transgenic plants, or cultured plant tissues or animal tissues.

[0166] In one embodiment, the host cell is eukaryotic. In another embodiment, the host cell is selected from yeast cells, mammalian cells (e.g., CHO cells (e.g., CHO-S or CHO-K or CHO-K1) or 293 cells (e.g., 293T, 293F or HEK293 cells)) or other cells suitable for preparing antibodies or fragments thereof. In one embodiment, the host cell is prokaryotic, for example, a bacterium, such as Escherichia coli.

[0167] For example, eukaryotic microorganisms such as filamentous fungi or yeast are suitable cloning or expression hosts for vectors encoding antibodies. Vertebrate cells can also be used as hosts. For example, mammalian cell lines modified to be suitable for suspension growth can be used. Other examples of useful mammalian host cell lines are monkey kidney CV1 lines (COS-7) transformed with SV40; human embryonic kidney lines (HEK293, 293F or 293T cells) and the like. Other useful mammalian host cell lines include Chinese hamster ovary (CHO) cells, including CHO-S cells or CHO-K or CHO-K1, and myeloma cell lines such as Y0, NS0 and Sp2 / 0. Mammalian host cell lines suitable for producing antibodies are known in the art.

[0168] In a sixth aspect of the present invention, the present invention provides a method for preparing an anti-CD105 antibody or fragment thereof (preferably an antigen-binding fragment), wherein the method comprises culturing the host cell under conditions suitable for expressing a nucleic acid encoding the antibody or fragment thereof (preferably an antigen-binding fragment) or either one or both chains thereof, and optionally isolating the antibody or fragment thereof (preferably an antigen-binding fragment). In a certain embodiment, the method further comprises recovering the anti-CD105 antibody or fragment thereof (preferably an antigen-binding fragment) from the host cell.

[0169] The polynucleotide encoding the polypeptide chains of the antibodies or antigen-binding fragments thereof of the present invention can be inserted into one or more vectors for further cloning and / or expression in host cells. Methods well known to those skilled in the art can be used to construct expression vectors. Once an expression vector comprising one or more nucleic acid molecules of the present invention has been prepared for expression, the expression vector can be transfected or introduced into a suitable host cell. A variety of techniques can be used to achieve this purpose, for example, protoplast fusion, calcium phosphate precipitation, electroporation, retroviral transduction, viral transfection, gene gun, liposome-based transfection or other conventional techniques.

[0170] Antibodies prepared as described herein can be purified by known techniques such as high performance liquid chromatography, ion exchange chromatography, gel electrophoresis, affinity chromatography, e.g., Protein A, size exclusion chromatography, etc. The actual conditions used to purify a particular protein will also depend on factors such as net charge, hydrophobicity, hydrophilicity, etc., and these will be apparent to those skilled in the art.

[0171] The purity of the antibody molecules of the present invention can be determined by any of a number of well-known analytical methods, including size exclusion chromatography, gel electrophoresis, high performance liquid chromatography, and the like.

[0172] In a seventh aspect of the present invention, methods or assays are provided for identifying, screening or characterizing the physical and / or chemical properties and / or biological activities of the anti-CD105 antibodies provided herein.

[0173] In one aspect, the antibodies of the invention are tested for their antigen binding activity, for example, by known methods such as thin-layer interferometry, ELISA, etc. Binding to CD105 can be determined using methods known in the art, for example, using radioimmunoassay (RIA) or thin-layer interferometry (BLI) or electrochemiluminescence (ECL) or surface plasmon resonance (SPR) or flow cytometry (FACS) measurement.

[0174] In some embodiments, the present invention provides an assay for identifying an anti-CD105 antibody having biological activity. The biological activity is selected from the properties of the antibodies of the present invention and can include, for example, binding to CD105 (e.g., binding to human or rhesus CD105), endocytic activity, or cytotoxicity or anti-tumor activity against CD105-positive cells (e.g., CD105-positive tumor cells).

[0175] For example, the binding activity of the antibody molecules of the present invention to CD105 or cells expressing CD105 can be determined by methods known in the art, such as Fortebio, flow cytometry, radioimmunoassay (RIA) or biofilm thin layer interferometry (BLI) or electrochemiluminescence (ECL) or surface plasmon resonance (SPR), Octet or plasma resonance (Biacore), or the exemplary method disclosed in Example 3 herein.

[0176] For example, the endocytic activity of the antibody molecules of the present invention against cells (e.g., CD105-positive cells, such as CD105-overexpressing cells) can be determined by methods known in the art, such as DT3C (e.g., the classic DT3C method), or the exemplary method disclosed in Example 4 herein.

[0177] For example, the cell-killing activity or anti-tumor activity of an antibody molecule of the present invention or an immunoconjugate comprising the same, such as an antibody-drug conjugate, against cells (e.g., CD105-positive cells, such as CD105-positive tumor cells) can be determined by methods known in the art, such as cell killing assays, such as in vitro cell killing assays, or in vivo animal model assays, or the exemplary methods disclosed in Examples 7, 8, or 9 herein.

[0178] Cells for use in any of the above in vitro assays include cell lines that naturally express CD 105 or are engineered to express CD 105. Such cells also include cell lines that express CD 105 and cell lines transfected with DNA encoding CD 105 that do not normally express CD 105, such as the MV4-11 or 8305c cell lines.

[0179] It will be appreciated that any of the above assays can be performed using an immunoconjugate of the invention, eg, an antibody drug conjugate, in place of or in addition to an anti-CD105 antibody.

[0180] It will be appreciated that any of the above assays can be performed using an anti-CD105 antibody or immunoconjugate thereof in combination with other active agents.

[0181] In an eighth aspect of the present invention, a composition, such as a pharmaceutical composition or a pharmaceutical formulation, is provided, which comprises the antibody or antigen-binding fragment thereof or an immunoconjugate thereof, such as an antibody-drug conjugate, of the present invention.

[0182] As used herein, the term "pharmaceutical composition" refers to a composition that is in a form that permits the biological activity of the active ingredient contained therein to be effective, and that contains no additional ingredients that are unacceptably toxic to a subject to which the composition would be administered.

[0183] In some embodiments, the pharmaceutical composition or pharmaceutical formulation further comprises a pharmaceutical excipient, such as a pharmaceutical carrier, a pharmaceutical excipient, including a buffer, as known in the art. As used herein, "pharmaceutical carrier" includes any and all solvents, dispersion media, isotonic agents, and absorption delaying agents that are physiologically compatible. For the use and application of pharmaceutical excipients, see also "Handbook of Pharmaceutical Excipients", 8th edition, RC Rowe, PJ Eskey and S C Owen, Pharmaceutical Press, London, Chicago.

[0184] The compositions or formulations of the present invention can be in a variety of forms. These forms include, for example, liquid, semisolid and solid dosage forms, such as liquid solutions (e.g., injectable solutions and infusible solutions), powders or suspensions, liposomes and suppositories. The preferred form depends on the intended mode of administration and therapeutic use.

[0185] Pharmaceutical formulations containing the antibodies or immunoconjugates thereof described herein can be prepared by mixing the antibodies or immunoconjugates thereof of the present invention having the desired degree of purity with one or more pharmaceutical excipients, preferably in the form of lyophilized formulations or aqueous solutions.

[0186] The pharmaceutical composition of the present invention or preparation can also comprise more than a kind of active ingredient, and described active ingredient is required for the specific indication being treated, preferably has those active ingredients of complementary activity that can not adversely affect each other.For example, it is desirable to also provide other therapeutic agents, such as chemotherapeutics, cytokines, cytotoxic agents, other antibodies, small molecule drugs or immunomodulators (such as immunosuppressants).Described active ingredient is suitably combined with the effective amount for purpose use and exists.

[0187] In a ninth aspect of the present invention, a pharmaceutical combination or pharmaceutical combination product is provided, comprising an anti-CD105 antibody or fragment thereof (preferably an antigen-binding fragment) of the present invention, or an immunoconjugate thereof, such as an antibody-drug conjugate, and one or more other therapeutic agents (e.g., chemotherapeutic agents, cytokines, cytotoxic agents, other antibodies, vaccines, small molecule drugs, or immunomodulatory agents (e.g., immunosuppressants).

[0188] As used herein, the term "drug combination or combination product" refers to a non-fixed combination product or a fixed combination product, including but not limited to a kit / test kit. The term "non-fixed combination" means that the active ingredients (e.g., (i) an antibody of the invention or its antibody drug conjugate, and (ii) other therapeutic agent) are administered to a patient simultaneously, without specific time restrictions, or sequentially at the same or different time intervals, as separate entities, wherein such administration provides prophylactically or therapeutically effective levels of two or more active agents in the patient's body. The term "fixed combination" means that two or more active agents are administered to a patient simultaneously in the form of a single entity. The dosage and / or time interval of the two or more active agents are preferably selected so that the combined use of the parts can produce an effect greater than that achieved by using any one component alone when treating a disease or condition. Each component can be in the form of a separate formulation, which can be the same or different.

[0189] In a tenth aspect of the present invention, a kit is provided, comprising the pharmaceutical combination of the present invention, preferably in the form of a pharmaceutical dosage unit, whereby dosage units can be provided according to a dosing regimen or a drug administration interval.

[0190] In one embodiment, the kit of parts of the present invention comprises in the same package:

[0191] - a first container containing a pharmaceutical composition comprising an anti-CD105 antibody or fragment thereof or an immunoconjugate thereof, such as an antibody drug conjugate;

[0192] - A second container containing a pharmaceutical composition comprising another therapeutic agent, such as a chemotherapeutic agent, a cytokine, a cytotoxic agent, another antibody, a vaccine, a small molecule drug, or an immunomodulatory agent (e.g., an immunosuppressant).

[0193] In the eleventh aspect of the present invention, a method for preventing or treating a disease, such as a CD105-related disease, in a subject is provided, comprising administering to the subject an effective amount (e.g., a prophylactically effective amount or a therapeutically effective amount) of an anti-CD105 antibody or antigen-binding fragment thereof, immunoconjugate, pharmaceutical composition or combination product of the present invention.

[0194] As used herein, "treat," ...

[0195] As used herein, "prevention" includes the inhibition of the onset or development of a disease or condition or symptoms of a particular disease or condition.

[0196] The term "effective amount" as used herein refers to an amount or dosage of an antibody or fragment or immunoconjugate or composition or combination of the invention which, after single or multiple doses, produces the desired effect in a patient in need of treatment or prevention.

[0197] As used herein, a "therapeutically effective amount" refers to an amount effective to achieve the desired therapeutic outcome at the desired dosage and for the desired period of time. A therapeutically effective amount is also an amount in which any toxic or deleterious effects of the antibody or antibody fragment or immunoconjugate or composition or combination are outweighed by the therapeutically beneficial effects. A "therapeutically effective amount" preferably inhibits a measurable parameter (e.g., tumor volume) or improves a measurable parameter by at least about 40%, even more preferably by at least about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or even 100%, relative to an untreated subject.

[0198] As used herein, a "prophylactically effective amount" refers to an amount effective to achieve the desired prophylactic result at the required dosage and for the required period of time. Typically, a prophylactic effective amount will be less than a therapeutically effective amount because a prophylactic dose is used in a subject prior to or at an earlier stage of the disease.

[0199] "Individual" or "subject" or "object" includes mammals. Mammals include, but are not limited to, domestic animals (e.g., cattle, sheep, cats, dogs, and horses), primates (e.g., humans and non-human primates such as monkeys), rabbits, and rodents (e.g., mice). In some embodiments, the individual or subject is a human.

[0200] In some embodiments, the CD105-related disease described herein is a disease associated with abnormal growth and / or dysfunction of tumor stromal cells, such as a tumor, such as cancer.

[0201] In some embodiments, the CD105-related diseases described herein include tumors, such as cancer. The cancer may be in the early, middle or late stages or may be metastatic. In some embodiments, the cancer may be a solid tumor or a blood tumor. In some embodiments, the cancer is selected from leukemia (e.g., human myelomonocytic leukemia), thyroid cancer, colorectal cancer, small cell lung cancer, melanoma, prostate cancer, breast cancer, liver cancer, ovarian cancer, or gastric cancer.

[0202] In some embodiments, the tumor is a CD105 positive tumor, such as a CD105 positive cancer. In one embodiment, the CD105 positive tumor refers to an individual's tumor tissue or tumor cells, such as compared to the adjacent normal tissues or normal cells (such as normal cells in tissue) or the same tissue of a healthy individual or the cell therein, with CD105 expression or with CD105 nucleic acids, or by comparison, CD105 protein levels (such as expression) increase, or CD105 nucleic acid levels increase. In one embodiment, the CD105 positive cancer refers to an individual's cancer tissue or cancer cells, such as compared to the adjacent normal tissues or normal cells (such as normal cells in tissue) or the same tissue of a healthy individual or the cell therein, with CD105 expression or with CD105 nucleic acids, or by comparison, CD105 protein levels (such as expression) increase, or CD105 nucleic acid levels increase.

[0203] In some embodiments, the antibodies or antibody fragments or immunoconjugates or compositions or formulations or combination products of the invention delay the onset of a disorder and / or symptoms associated with the disorder.

[0204] In some embodiments, the prophylactic or therapeutic methods described herein further comprise administering to the subject or individual an antibody or antigen-binding fragment thereof or immunoconjugate or pharmaceutical composition disclosed herein in combination with one or more other therapies, e.g., treatment modalities and / or other therapeutic agents.

[0205] In some embodiments, treatment modalities include surgery, radiation therapy (e.g., external beam radiation therapy, which involves three-dimensional conformal radiation therapy in which the irradiation area is designed), local irradiation (e.g., irradiation directed to a preselected target or organ), or focused irradiation), etc.

[0206] In some embodiments, the therapeutic agent is selected from a chemotherapeutic agent, a cytokine, a cytotoxic agent, other antibodies, a vaccine, a small molecule drug, or an immunomodulator (e.g., an immunosuppressant or activator), among others.

[0207] In some embodiments, the antibodies described herein can be combined with other antibodies for separate administration, e.g., each as a separate antibody, or when linked (e.g., as a bispecific or multispecific antibody molecule).

[0208] Combination therapies of the invention encompass both combined administration (e.g., two or more therapeutic agents contained in the same formulation or separate formulations), and separate administration, in which case administration of the antibodies of the invention (as well as immunoconjugates, compositions, pharmaceutical compositions, formulations, etc. comprising the same) can occur before, simultaneously with, and / or after administration of the additional therapeutic and / or pharmaceutical agents.

[0209] The anti-CD105 antibodies of the present invention (and immunoconjugates, compositions, pharmaceutical compositions, formulations, combination products, etc. comprising the same) can be administered by any suitable method, including parenteral administration, and, if desired for local treatment, intralesional administration. Parenteral injection or infusion includes intramuscular, intravenous, intraarterial, intraperitoneal or subcutaneous injection or infusion. Depending on whether the medication is short-term or long-term, the medication can be administered by any suitable route, such as by injection, such as intravenous or subcutaneous injection. Various medication schedules are contemplated herein, including, but not limited to, single administration or multiple administrations at multiple time points, bolus administration, and pulse infusion.

[0210] In other aspects, the present invention provides the use of an anti-CD105 antibody or fragment thereof, or an immunoconjugate or composition or combination product comprising the same, of the present invention in the production or preparation of a medicament for the uses described herein, such as for preventing or treating the relevant diseases or conditions mentioned herein.

[0211] In other aspects, the present invention provides an anti-CD105 antibody or fragment thereof of the present invention, or an immunoconjugate or composition or combination product comprising the same, for use in therapy, such as for treating the relevant diseases or disorders mentioned herein.

[0212] In the twelfth aspect of the present invention, the present invention also relates to methods for diagnosis and detection of the antibodies or antigen-binding fragments thereof of the present invention and compositions for diagnosis and detection comprising the same.

[0213] In certain embodiments, any of the anti-CD105 antibodies or antigen-binding fragments thereof provided herein can be used to detect the presence of CD105 in a biological sample.

[0214] The term "detection" as used herein includes quantitative or qualitative detection, and exemplary detection methods can involve immunohistochemistry, immunocytochemistry, flow cytometry (e.g., FACS), magnetic beads of antibody molecule complexes, ELISA assays, PCR-techniques (e.g., RT-PCR). In certain embodiments, the biological sample is other liquid samples of blood, serum, or biological origin. In certain embodiments, the biological sample comprises cells or tissues. In some embodiments, the biological sample is from tumor tissue or cancer tissue.

[0215] In one embodiment, an anti-CD105 antibody or antigen-binding fragment thereof, or a kit comprising the same, is provided for use in a diagnostic or detection method.

[0216] In another aspect, a method for detecting the presence of CD105 in a biological sample is provided. In certain embodiments, the method comprises detecting the presence of CD105 protein in a biological sample. In certain embodiments, CD105 is human CD105 or rhesus monkey CD105.

[0217] In certain embodiments, the method comprises contacting a biological sample with an anti-CD105 antibody as described herein under conditions that allow the anti-CD105 antibody to bind to CD105, and detecting whether a complex is formed between the anti-CD105 antibody and CD105. The formation of a complex indicates the presence of CD105. The method can be an in vitro or in vivo method.

[0218] In one embodiment, an anti-CD 105 antibody is used to select a subject suitable for treatment with the anti-CD 105 antibody, eg, where CD 105 is a biomarker used to select the subject.

[0219] In certain embodiments, labeled antibodies or fragments thereof are provided. Labels include, but are not limited to, directly detected labels or moieties (such as fluorescent labels, chromophore labels, electron-dense labels, chemiluminescent labels, and radioactive labels), as well as indirectly detected moieties, such as enzymes or ligands, e.g., by enzymatic reactions or molecular interactions.

[0220] In some embodiments provided herein, the sample is obtained prior to treatment with an antibody or fragment thereof of the present invention. In some embodiments, the sample is obtained prior to treatment with an alternative therapy. In some embodiments, the sample is obtained during treatment with an alternative therapy, or after treatment with an alternative therapy.

[0221] In some embodiments, CD105 is detected prior to treatment, eg, prior to initiation of treatment or prior to a treatment following a treatment interval.

[0222] In some embodiments, a method for treating a CD105-related disease of the present invention is provided, comprising: testing a subject (e.g., a sample) (e.g., a subject sample) for the presence of CD105, thereby determining a CD105 value, comparing the CD105 value with a control value (e.g., the same tissue or cell of a healthy individual or the value in adjacent normal tissue or cells of the patient to be tested), and if the CD105 value is greater than the control value, administering to the subject a therapeutically effective amount of an antibody or fragment thereof, or an antibody-drug conjugate, composition, pharmaceutical composition, formulation or combination product comprising the same, optionally in combination with one or more other therapies, thereby treating the disease.

[0223] In some embodiments, a method for diagnosing a CD105-related disease is provided, comprising: applying the antibody or antigen-binding fragment thereof of the present invention, or a kit comprising the same, to test a subject (e.g., a sample) (e.g., a subject sample) for CD105, wherein if CD105 is present or greater than the CD105 value in the control compared to a control (e.g., the same tissue or cell of a healthy individual or adjacent normal tissue or cell of a patient to be tested), the CD105-related disease is diagnosed.

[0224] In some embodiments, a kit for diagnosing a CD105-related disease is provided, comprising the antibody or antigen-binding fragment thereof of the present invention.

[0225] In the thirteenth aspect of the present invention, the present invention relates to the following specific embodiments:

[0226] 1. An antibody or antigen-binding fragment thereof that specifically binds to CD105, the antibody comprising

[0227] 1) the three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO: 1, and the three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO: 2;

[0228] 2) three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO: 15, and three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO: 16;

[0229] 3) three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO: 29, and three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO: 30;

[0230] 4) the three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO:41, and the three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO:42; or

[0231] 5) the three complementarity determining regions HCDR1, HCDR2, and HCDR3 contained in the VH as shown in SEQ ID NO: 50, and the three complementarity determining regions LCDR1, LCDR2, and LCDR3 contained in the VL as shown in SEQ ID NO: 51;

[0232] Preferably, the HCDR and the LCDR are determined according to the IMGT scheme, or are determined according to the Kabat scheme, respectively.

[0233] 2. An antibody or antigen-binding fragment thereof that specifically binds to CD105, the antibody comprising three complementarity determining regions (HCDR1, HCDR2, and HCDR3) of a heavy chain variable region, and three complementarity determining regions (LCDR1, LCDR2, and LCDR3) of a light chain variable region, wherein the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3, as determined based on the IMGT protocol, respectively comprise or consist of the amino acid sequence shown in the following table:

[0234] Or wherein the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 determined based on the Kabat scheme respectively comprise or consist of the amino acid sequences shown in the following table SEQ ID NO:

[0235] 3. The antibody or antigen-binding fragment thereof that binds to CD105 according to embodiment 1 or 2, wherein the antibody comprises a heavy chain variable region, wherein the heavy chain variable region comprises or consists of an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from the group consisting of SEQ ID NO: 1, 15, 29, 41 or 50; or the heavy chain variable region comprises or consists of an amino acid sequence selected from the group consisting of SEQ ID NO: 1, 15, 29, 41 or 50; and / or

[0236] The antibody comprises a light chain variable region, wherein the light chain variable region comprises an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 2, 16, 30, 42 or 51, or consists of said sequence; or the light chain variable region comprises an amino acid sequence selected from SEQ ID NO: 2, 16, 30, 42 or 51, or consists of said sequence.

[0237] 4. An antibody or antigen-binding fragment thereof that binds to CD105, said antibody comprising a heavy chain variable region and a light chain variable region, wherein

[0238] a) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 1, and the light chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 2;

[0239] b) the heavy chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 15, and the light chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 16;

[0240] c) the heavy chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 29, and the light chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 30;

[0241] d) the heavy chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO:41, and the light chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO:42;

[0242] e) the heavy chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 50, and the light chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 51;

[0243] f) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 1, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 2;

[0244] g) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 15, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 16;

[0245] h) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 29, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 30;

[0246] i) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 41, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 42; or

[0247] j) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 50, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 51.

[0248] 5. The antibody or antigen-binding fragment thereof that binds to CD105 according to embodiment 1 or 2, wherein the antibody comprises a heavy chain variable region and a light chain variable region, wherein

[0249] a) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 1, and the light chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 2;

[0250] b) the heavy chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 15, and the light chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 16;

[0251] c) the heavy chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 29, and the light chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO: 30;

[0252] d) the heavy chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO:41, and the light chain variable region comprises, or consists of, an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO:42;

[0253] e) the heavy chain variable region comprises, or consists of, an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 50, and the light chain variable region comprises, or consists of, an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 51;

[0254] f) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 1, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 2;

[0255] g) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 15, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 16;

[0256] h) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 29, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 30;

[0257] i) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 41, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 42; or

[0258] j) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 50, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 51.

[0259] 6. An antibody or antigen-binding fragment thereof that binds to CD105 as described in any one of embodiments 1-5, wherein the antibody comprises a heavy chain constant region, such as a heavy chain constant region of IgG1, IgG2, IgG3, or IgG4, such as a heavy chain constant region of IgG1, for example,

[0260] (i) comprises an amino acid sequence that is at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 66; or

[0261] (ii) comprising or consisting of the amino acid sequence of SEQ ID NO: 66.

[0262] 7. An antibody or antigen-binding fragment thereof that binds to CD105 as described in any one of embodiments 1-6, wherein the antibody comprises a light chain constant region, such as a lambda or kappa light chain constant region, such as the light chain constant region

[0263] (i) comprises or consists of an amino acid sequence that is at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 67 or 68; or

[0264] (ii) comprises or consists of an amino acid sequence selected from SEQ ID NO: 67 or 68.

[0265] 8. An antibody or antigen-binding fragment thereof that binds to CD105 as described in any one of embodiments 1-7, wherein the antibody comprises a heavy chain constant region and a light chain constant region, wherein

[0266] The heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66; and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 67 or 68.

[0267] 9. An antibody or antigen-binding fragment thereof that binds to CD105 as described in any one of embodiments 1-8, wherein the antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises a heavy chain variable region and a heavy chain constant region or consists of a heavy chain variable region and a light chain variable region, and the light chain comprises a light chain variable region and a light chain constant region or consists of a heavy chain variable region and a light chain variable region, wherein

[0268] (i) the heavy chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 1, the light chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 2, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 67;

[0269] (ii) the heavy chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 15, the light chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 16, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 68;

[0270] (iii) the heavy chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 29, the light chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 30, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 68;

[0271] (iv) the heavy chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 41, the light chain variable region comprises or consists of the amino acid sequence of SEQ ID NO: 42, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 68; or

[0272] (v) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 50, the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 51, the heavy chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 68.

[0273] 10. The antibody or antigen-binding fragment thereof that binds to CD105 according to any one of embodiments 1-8, which has one or more of the following characteristics:

[0274] (1) capable of specifically binding to CD105 with high affinity, such as binding to human or rhesus CD105;

[0275] (2) can specifically bind to CD105 expressed on the cell membrane surface with high affinity, such as human or rhesus monkey CD105;

[0276] (3) being able to induce endocytosis of the antibody or its fragment or a molecule comprising the antibody or its fragment (e.g., an immunoconjugate such as ADC) by CD105-positive cells (e.g., CHO cells overexpressing CD105);

[0277] (4) Ability to target and kill CD105-positive cells, such as CD105-positive tumor cells;

[0278] (6) capable of treating tumors such as cancer, for example, treating CD105-positive tumors, such as CD105-positive cancers;

[0279] (7) Suitable for constructing immunoconjugates (e.g., antibody-drug conjugates (ADCs) for targeted killing of CD105-positive cells, such as CD105-positive tumor cells; or for treating tumors such as cancer, such as CD105-positive tumors, such as CD105-positive cancers;

[0280] (8) exhibiting the same or similar binding affinity and / or specificity for CD105 as any of the antibodies listed in Embodiment 9;

[0281] (9) inhibiting the binding of any antibody listed in Embodiment 9 to CD105;

[0282] (10) binds to the same or overlapping epitope as any of the antibodies described in embodiment 9; or

[0283] (11) Compete with any of the antibodies shown in Embodiment 9 for binding to CD105.

[0284] 11. The antibody or antigen-binding fragment thereof according to any one of embodiments 1-10, wherein the antibody is a monoclonal antibody.

[0285] 12. The antibody or antigen-binding fragment thereof of any one of embodiments 1-11, wherein the antibody is a human antibody.

[0286] 13. The antibody or antigen-binding fragment thereof according to any one of embodiments 1-12, wherein the antigen-binding fragment is an antibody fragment selected from the group consisting of: Fab, Fab', Fab'-SH, Fv, a single-chain antibody such as scFv, a (Fab')2 fragment, a single-domain antibody, a diabody, or a linear antibody.

[0287] 14. The antibody or antigen-binding fragment thereof of embodiment 13, wherein the single-chain antibody is scFv.

[0288] 15. The antibody or antigen-binding fragment thereof according to any one of claims 1 to 14, wherein the antibody is a bispecific antibody or a multispecific antibody.

[0289] 16. An isolated nucleic acid encoding the anti-CD105 antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15.

[0290] 17. An expression vector comprising the nucleic acid of embodiment 16.

[0291] 18. The expression vector according to embodiment 17, wherein the expression vector is a pCDNA vector, such as a pCDNA3.4 vector.

[0292] 19. A host cell comprising the nucleic acid of embodiment 16 or the expression vector of embodiment 17 or 18.

[0293] 20. The host cell of embodiment 19, wherein the host cell is prokaryotic or eukaryotic.

[0294] 21. The host cell of embodiment 20, wherein the host cell is selected from Escherichia coli cells, yeast cells, mammalian cells or other cells suitable for preparing antibodies or antigen-binding fragments thereof.

[0295] 22. The host cell of embodiment 21, wherein the host cell is a 293 cell or a CHO cell.

[0296] 23. A method for preparing an anti-CD105 antibody or an antigen-binding fragment thereof, the method comprising culturing the host cell of any one of embodiments 19-22 under conditions suitable for expression of a nucleic acid encoding the anti-CD105 antibody or antigen-binding fragment thereof of any one of embodiments 1 to 15, optionally isolating the antibody or antigen-binding fragment thereof, and optionally further comprising recovering the anti-CD105 antibody or antigen-binding fragment thereof from the host cell.

[0297] 24. An immunoconjugate comprising the antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15 and another therapeutic agent, preferably, the immunoconjugate is an antibody drug conjugate.

[0298] 25. The immunoconjugate of embodiment 24, wherein the other therapeutic agent is a cytotoxic agent, such as MMAE, and optionally, the MMAE is coupled to the antibody or its antigen-binding fragment via a Vc linker, for example, the antibody or its antigen-binding fragment is connected to VcMMAE to form an antibody-drug conjugate.

[0299] 26. A pharmaceutical composition comprising the antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15 or the immunoconjugate according to embodiment 24 or 25, and optionally a pharmaceutically acceptable excipient.

[0300] 27. A pharmaceutical composition comprising the antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15 or the immunoconjugate according to embodiment 24 or 25, and another therapeutic agent.

[0301] 28. A pharmaceutical combination comprising the antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15 or the immunoconjugate according to embodiment 24 or 25, and another therapeutic agent.

[0302] 29. The pharmaceutical composition of embodiment 27 or the pharmaceutical combination of embodiment 28, wherein the other therapeutic agent is selected from a chemotherapeutic agent, a cytokine, a cytotoxic agent, another antibody, a small molecule drug or an immunomodulator (e.g., an immunosuppressant).

[0303] 30. Use of an effective amount of an anti-CD105 antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15, or an immunoconjugate according to embodiment 24 or 25, or a pharmaceutical composition according to embodiment 26 in the preparation of a medicament for preventing or treating a subject or individual tumor in a subject, e.g., the tumor is a CD105-positive tumor.

[0304] 31. The use of any one of embodiment 30, wherein the tumor is a solid tumor or a blood tumor, for example, the tumor is a cancer, for example, a CD105-positive cancer, for example, the cancer is selected from leukemia (for example, human myelomonocytic leukemia), thyroid cancer, colorectal cancer, small cell lung cancer, melanoma or prostate cancer, etc.

[0305] 32. The use of embodiment 30 or 31, wherein the drug is also administered to the subject in combination with one or more other therapies.

[0306] 33. The use of embodiment 32, wherein the therapy comprises a treatment modality and / or other therapeutic agents.

[0307] 34. The use according to embodiment 33, wherein the other therapeutic agent is selected from a chemotherapeutic agent, a cytokine, other antibodies, a cytotoxic agent, a vaccine, a small molecule drug or an immunomodulator (such as an immunosuppressant or activator), and / or the treatment modality comprises surgery and / or radiotherapy.

[0308] 35. A method for detecting CD105 in a sample, the method comprising

[0309] (a) contacting the sample with the CD105-binding antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15; and

[0310] (b) detecting formation of a complex between the anti-CD105 antibody or antigen-binding fragment thereof and CD105; optionally, the anti-CD105 antibody is detectably labeled.

[0311] 36. A kit comprising the CD105-binding antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15.

[0312] 37. Use of the CD105-binding antibody or antigen-binding fragment thereof according to any one of embodiments 1 to 15 in the preparation of a kit for diagnosing CD105-positive tumors, such as CD105-positive cancers.

[0313] All publications, patent applications, patents and other references mentioned herein are incorporated herein by reference in their entirety. Any or all features discussed above and throughout this application can be combined in various embodiments of the present invention. In addition, the materials, methods and examples described herein are only illustrative and are not intended to be restrictive. Other features, purposes and advantages of the present invention will become apparent from this specification and accompanying drawings and from the appended claims. Example:

[0314] Example 1: Species Sequence Homology of CD105 Antigen and Construction of Stable High-Expression Cell Line

[0315] Homology analysis of CD105 sequences from different species (human CD105 (hCD105, SEQ ID NO: 63), rhesus macaque CD105 (RhCD105, SEQ ID NO: 64), and mouse CD105 (mCD105, SEQ ID NO: 65)) revealed high homology between humans and rhesus macaques. The sequence homology between human CD105 and rhesus macaque C105 is 93.2%, while that between human CD105 and mouse CD105 is 68.1% (see Table 1).

[0316] Table 1: Sequence homology of CD105 in different species

[0317] The coding nucleic acids of human CD105 (SEQ ID NO: 63), mouse CD105 (SEQ ID NO: 65) and rhesus monkey CD105 (SEQ ID NO: 64) were cloned into the expression vector pCDNA3.1 (+) (Qingke Bioconstruction) and lipofectamine was used to express TM CHO-K1 cells (Kebai Bio, Cat: CBP60296) were transfected with 3000 transfection reagent (Thermo Fisher, L3000075). Seven days after transfection, cells were sorted by flow cytometry. The primary antibody was OMTX003 (67 nM) (OMTX003 antibody heavy chain: SEQ ID NO: 28; OMTX003 antibody light chain: SEQ ID NO: 14), and the secondary antibody was goat anti-human IgG H&L (FITC) (Abcam, ab6854). Cells with a positive rate of 2.5% were selected for culture and flow cytometric analysis was performed before the completion of the stable cell line culture. CHO stable cells that highly express human CD105 were named CHO-hCD105, CHO stable cells that highly express mouse CD105 were named CHO-mCD105, and CHO stable cells that highly express rhesus monkey CD105 were named CHO-RhCD105. CHO-hCD105, CHO-mCD105, and CHO-RhCD105 were detected by flow cytometry. The primary antibody was OMTX003 (67 nM) (OMTX003 antibody heavy chain: SEQ ID NO: 28; OMTX003 antibody light chain: SEQ ID NO: 14) and the secondary antibody was goat anti-human IgG H&L (FITC) (Abcam, ab6854). The results are shown in Figure 1, where the left figure shows the flow cytometry results for CHO-hCD105, the middle figure shows the flow cytometry results for CHO-RhCD105, and the right figure shows the flow cytometry results for CHO-mCD105. The results showed that CHO-hCD105, CHO-mCD105, and CHO-RhCD105 cells highly expressed hCD105, mCD105, and RhCD105, respectively.

[0318] Example 2 Screening of CD105-specific antibodies using a fully human scFv phage library

[0319] Fully human scFv phage antibody screening process: Add 2×10^12 blocked phage libraries to "negative panning" magnetic beads, mix thoroughly by inversion, and incubate on a rotary mixer at 37°C, 20 rpm for 1 hour. Transfer the supernatant to "positive panning" magnetic beads adsorbed with hCD105 antigen, mix thoroughly by inversion, and incubate on a rotary mixer at 37°C, 20 rpm for 1 hour. Wash nine times with PBST, aspirate the supernatant, add 600 μL of elution buffer (0.1 M Gly-HCl, pH 2.2), mix thoroughly by inversion, and incubate at room temperature, 20 rpm, for 10 minutes. Aspirate the supernatant and add it to 200 μL of neutralization buffer (1 M Tris-HCl, pH 8.0) and mix thoroughly. This mixture is the eluted phage, which is amplified and panned again. After three rounds of panning, the ELISA OD values ​​(450 nM) of the phage supernatant and hCD105-his antigen (hCD105 containing six His tags) and RhCD105-his antigen (RhCD105 containing six His tags) were detected to obtain positive clones. The results are shown in Table 2.

[0320] Table 2: CD105-specific phage clones (ELISA OD value (450 nM))

[0321] The five positive phage clones were sequenced and identified to obtain sequence results. The sequences of the light chain variable region and heavy chain variable region of the scFv obtained by screening are specifically shown in the sequence table.

[0322] Example 3 Construction of IgG Antibody and FACS Detection of Binding Activity to CD105 Overexpressing Cells

[0323] IgG antibody preparation

[0324] The nucleic acids encoding the antibody light and heavy chain variable region sequences were cloned into expression vector pCDNA 3.4 containing the nucleic acid encoding the heavy chain constant region (SEQ ID NO: 66) or the light chain constant region (SEQ ID NO: 67; SEQ ID NO: 68) (see the table below for combinations). The vectors were co-transfected into CHO suspension cells for expression. The cell supernatant was collected and purified using a Protein A column. The purified antibodies were analyzed for size and purity by SDS-PAGE and HPLC-SEC.

[0325] Detection of IgG antibody binding activity to cells

[0326] The CD105 overexpressing cells (CHO-hCD105, CHO-mCD105 and CHO-RhCD105) prepared in Example 1 were digested with trypsin and cultured at 1×10 6100 μL of each antibody was added to a U-bottom 96-well plate. Then, each antibody (9B1, 9E12, 11F11, 13E4, 14B1, OMTX003 (OMTX003 antibody heavy chain: SEQ ID NO: 28; OMTX003 antibody light chain: SEQ ID NO: 14) was diluted with PBS, with a starting concentration of 80 nM and 3-fold dilution for a total of 8 concentrations. 100 μL of diluted antibody was added to the cell plate to resuspend the cells, incubated at 4°C for 1 hour, and washed three times with PBS. The secondary antibody Anti-Human IgG H&L (FITC, Abcam, ab6854) was diluted 1:2000 with PBS, and 100 μL of diluted secondary antibody was added to the cell plate to resuspend the cells, incubated at 4°C for 1 hour, and washed three times with PBS. 100 μL of PBS was added to resuspend the cells, and the binding signal was detected by FACS, and the data was analyzed using Graphpad.

[0327] The results are shown in Figure 2 . The five antibodies 9B1, 9E12, 11F11, 13E4, and 14B1 can all cross-bind to cells expressing human and rhesus monkey CD105. The EC50s for binding to CHO-hCD105 cells were 4.22 nM, 4.19 nM, 4.61 nM, 5.32 nM, and 2.46 nM, respectively; the EC50s for binding to CHO-RhCD105 cells were 2.75 nM, 2.03 nM, 2.13 nM, 4.11 nM, and 0.87 nM, respectively; and the EC50s for binding to CHO-hCD105 and CHO-RhCD105 cells of the control antibody OMTX003 were 3.42 nM and 1.80 nM, respectively.

[0328] Example 4 Antibody endocytosis experiment

[0329] The antibody endocytosis experiment uses the classic DT3C method, as follows:

[0330] CD105-overexpressing cells (CHO-hCD105) in logarithmic growth phase were trypsinized and plated into 96-well plates at 5,000 cells / well in 100 μL of culture medium. The plates were incubated for 24 hours at 37°C in a 5% CO2 incubator. Recombinant DT3C protein (CUSABIO, CSB-EP360556CQR1) was diluted to 587 nM in cell culture medium (Ham's F-12K, 10% FBS).

[0331] Dilute the antibody to 267nM in cell culture medium. Mix the diluted recombinant DT3C protein and antibody in equal volumes to form a mixture and incubate at room temperature for 30 minutes. Dilute the mixture 3-fold with cell culture medium (Ham's F-12K, 10% FBS) for a total of 10 steps. Add 100μL of the diluted sample to the cell plate, mix well, and incubate in a 37°C, 5% CO2 constant temperature incubator for 48 hours. Add 20μL Cell Counting Kit-8 (CellorLab, CX001) and incubate in a 37°C, 5% CO2 constant temperature incubator for 3 hours. Measure the absorbance at 450nm using a microplate reader, and then analyze the data using Graphpad.

[0332] The results are shown in Figure 3. The mixtures of the five antibodies and the control antibody OMTX003 with DT3C all killed the cells, indicating that the antibodies were all internalized by the cells.

[0333] Example 5 Antibody epitope identification

[0334] Antibody epitope identification was performed using competitive ELISA, as follows:

[0335] The antibody was biotinylated using the EZ-Linker NHS Kit (Hermo Scientific, Cat: 20217). 2 nM of the labeled antibody was mixed with 240 nM of the unlabeled antibody at a molar ratio of 1:120. The mixture was incubated with CHO-hCD105 cells at 4°C for 1 hour. After incubation, the cells were washed three times with PBS and the supernatant was removed by centrifugation. SA-bio secondary antibody (FITC-streptavidin conjugate (AAT Bioquest, Cat: 16910)) was added to the sample, incubated at 4°C for 1.5 hours, and then washed three times with PBS. The supernatant was removed by centrifugation, and the cells were resuspended in 120 μL of PBS. Epitope binding was analyzed by FACS. Competitive binding was observed for 9B1, 11F11, 13E4, and OMTX003, belonging to the same antigenic determinant, Bin#1. Competitive binding was observed for 9E12 and 14B1, belonging to a different antigenic determinant, Bin#2. The results are shown in Table 3.

[0336] Table 3: Antibody epitopes

[0337] Example 6 Preparation of CD105 Antibody-Drug Conjugates

[0338] An appropriate amount of reducing agent (TCEP·HCl, Thermo, CAS No.: 51805-45-9) was added to reduce the antibodies (9B1, 9E12, 11F11, 13E4, and 14B1, as well as the control antibody OMTX003) to expose the sulfhydryl groups between the antibody chains. VcMMAE (MCE, CAS No.: 646502-53-6) was dissolved in DMSO and prepared into a 10 mM solution.

[0339] The dissolved VcMMAE was added at a molar ratio of 10:1 between the antibody and the linker-payload, and the antibody and VcMMAE were coupled together through a Michael addition reaction between the thiol group and the maleimide group on the linker.

[0340] The mixture after coupling was buffer exchanged to remove residual VcMMAE. The purity and DAR (drug / antibody ratio) value of the antibody conjugate after the reaction were determined by HPLC-SEC (size exclusion chromatography) and HPLC-HIC (hydrophobic chromatography), respectively. The coupling results of different candidate molecules are shown in Table 4.

[0341] Table 4: Preparation of CD105 Antibody-Drug Conjugates

[0342] Example 7 ADC in vitro cell killing experiment

[0343] 8305c (Nanjing Kebai, Cat: CBP60702) in the logarithmic growth phase were digested with trypsin and plated into a 96-well plate at 4000 cells / well and 100 μL; MV4-11 (Nanjing Kebai, Cat: CBP60522) were digested with trypsin and plated into a 96-well plate at 7000 cells / well and 100 μL. Both plates were placed in a constant temperature incubator at 37°C and 5% CO2 and incubated for 24 h.

[0344] The ADC prepared in Example 6 was diluted with cell culture medium (Ham's F-12K, 10% FBS, AusGenex, Cat: FBS500-S) to a starting concentration of 30,000 nM, and diluted 5-fold for a total of 10 gradients. 10 μL of the diluted sample was added to the cell plate, mixed, and incubated in a 37°C, 5% CO2 constant temperature incubator for 48 h. 10 μL of Cell Counting Kit-8 (CellorLab, CX001) was added and incubated in a 37°C, 5% CO2 constant temperature incubator for 3 h. The absorbance at 450 nm was measured using a microplate reader. The data were analyzed using Graphpad. The in vitro cytotoxicity of the CD105 antibody-drug conjugate is shown in Table 5, and the IC50 curve is shown in Figure 4.

[0345] Table 5: In vitro killing activity of CD105 antibody-conjugated drugs or linkers + toxins or toxins

[0346] Example 8 In vivo efficacy of MV4-11 CDX model

[0347] A subcutaneous xenograft tumor model was established in NPG mice (purchased from Beijing Weitongda Biotechnology Co., Ltd.) (Beijing Laboratory Animal Quality Certificate: 110341230100010057) using MV-4-11 human myelomonocytic leukemia cells (Nanjing Kebai, Cat: CBP60522), and the in vivo efficacy of each CD105 antibody-drug conjugate was evaluated.

[0348] Specifically, MV-4-11 cells were collected in the logarithmic growth phase, the culture medium was removed, and the cells were washed twice with PBS before being inoculated into the right back of NPG mice (6-8 weeks old nude mice) at a volume of 9*10^6 / 200μL / mouse (without adding Matrigel). After 12 days of inoculation, the tumors grew to an appropriate size and the tumor volume reached the standard (average tumor volume ≈ 285mm 3 Mice were randomly divided into 7 groups, with 5 animals in each group. They were blank control group (PBS only), positive control OMTX003-MMAE group, 9B1-MMAE group, 9E12-MMAE group, 11F11-MMAE group, 13E4-MMAE group, and 14B1-MMAE group. The solvent for all drugs was DPBS.

[0349] Dosing began on the day of grouping (day 0), with an ip dosage of 5 mg / kg, and the frequency of dosing was only once and continued for 21 days. After the start of group dosing, the weight and tumor volume of the mice were measured three times a week. Each time, the size of the mouse tumor was measured using a vernier caliper, and the volume was calculated as V = (L × W^2) / 2, where L is the longest diameter of the tumor and W is the shortest diameter perpendicular to the longest diameter. On the 21st day after group dosing, the experiment was terminated and all mice were euthanized.

[0350] The results are shown in Figure 5. All drug-treated groups (i.e., 9B1-MMAE group, 9E12-MMAE group, 11F11-MMAE group, 13E4-MMAE group, and 14B1-MMAE group) had significant tumor growth inhibition effects, and there were statistical differences compared with the blank control group (p<0.0001).

[0351] The final data showed that the tumor volume of the blank control group was 2622.5±160.3mm3; the tumor volume of the positive control OMTX003-MMAE group was 239.2±93.3mm 3The tumor volumes of the 9B1-MMAE group, 9E12-MMAE group, 11F11-MMAE group, 13E4-MMAE group, and 14B1-MMAE group were 515.8±188.5mm 3 、173.6±23.9mm 3 、241.6±47.0mm 3 、394.1±117.5mm 3 and 404.3±21.6mm 3 The above results indicate that all CD105 ADC drugs have strong tumor-suppressing activity.

[0352] Example 9 In vivo efficacy of 8305c CDX model

[0353] A subcutaneous xenograft tumor model was established in Balb / c-nude mice (purchased from Jiangsu Jicui Yaokang Biotechnology Co., Ltd.) (Jiangsu Province Laboratory Animal Quality Certificate: 202310907) using 8305c human thyroid cancer cells (Nanjing Kebai, Cat: CBP60702), and the in vivo efficacy of each CD105 antibody-drug conjugate was evaluated.

[0354] Specifically, 8305c cells were collected in the logarithmic growth phase, the culture medium was removed, and the cells were washed twice with PBS. The cells were then resuspended in serum-free DMEM containing double-antibody and inoculated into the right back of Balb / c-nude mice (6-8 weeks old) at a volume of 5*10^6 / 100μL / mouse (without adding Matrigel). After 23 days of inoculation, the tumors grew to an appropriate size and the tumor volume reached the standard (average tumor volume ≈ 210mm). 3 Mice were randomly divided into 6 groups, with 6 animals in each group. They were blank control group (PBS only), positive control OMTX003-MMAE group, 9E12-MMAE group, 11F11-MMAE group, 13E4-MMAE group, and 14B1-MMAE group. The solvent for all drugs was DPBS.

[0355] Dosing began on the day of grouping (day 0), with an ip dosage of 2.5 mg / kg, and the frequency of dosing was only once and continued for 12 days. After the start of group dosing, the weight and tumor volume of the mice were measured three times a week. Each time, a vernier caliper was used to measure the size of the mouse tumor, and the volume was calculated as V = (L × W^2) / 2, where L is the longest diameter of the tumor and W is the shortest diameter perpendicular to the longest diameter. On the 12th day after group dosing, the experiment was terminated and all mice were euthanized.

[0356] The results are shown in Figure 6. All drug-treated groups (i.e., 9E12-MMAE group, 11F11-MMAE group, 13E4-MMAE group, and 14B1-MMAE group) had significant tumor growth inhibition effects, and were statistically different from the blank control group (p<0.0001).

[0357] The final data showed that the tumor volume of the blank control group was 2647.6±378.5mm3; the tumor volume of the positive control OMTX003-MMAE group was 827.1±152.5mm 3 The tumor volumes of the 9E12-MMAE group, 11F11-MMAE group, 13E4-MMAE group, and 14B1-MMAE group were 631.5±162.6mm 3 、1271.4±97.2mm 3 , 913.8±187.7mm3 and 689.4±109.0mm3. The above results indicate that each CD105 ADC drug has a strong anti-tumor activity CD105.

[0358] Sequence Listing

Claims

1. An antibody or an antigen-binding fragment thereof that specifically binds to CD105, the antibody comprising 1) three complementary determining regions HCDR1, HCDR2 and HCDR3 contained in VH as shown in SEQ ID NO: 1, and three complementary determining regions LCDR1, LCDR2 and LCDR3 contained in VL as shown in SEQ ID NO: 2; 2) three complementary determining regions HCDR1, HCDR2 and HCDR3 contained in VH as shown in SEQ ID NO: 15, and three complementary determining regions LCDR1, LCDR2 and LCDR3 contained in VL as shown in SEQ ID NO: 16; 3) three complementary determining regions HCDR1, HCDR2 and HCDR3 contained in VH as shown in SEQ ID NO:29, and three complementary determining regions LCDR1, LCDR2 and LCDR3 contained in VL as shown in SEQ ID NO:30; 4) the three complementary determining regions HCDR1, HCDR2 and HCDR3 contained in the VH as shown in SEQ ID NO:41, and the three complementary determining regions LCDR1, LCDR2 and LCDR3 contained in the VL as shown in SEQ ID NO:42; or 5) three complementary determining regions HCDR1, HCDR2 and HCDR3 contained in VH as shown in SEQ ID NO:50, and three complementary determining regions LCDR1, LCDR2 and LCDR3 contained in VL as shown in SEQ ID NO:51; Preferably, the HCDR and the LCDR are determined according to the IMGT scheme, or are determined according to the Kabat scheme, respectively.

2. An antibody or antigen-binding fragment thereof that specifically binds to CD105, the antibody comprising three complementary determining regions HCDR1, HCDR2 and HCDR3 of the heavy chain variable region, and three complementary determining regions LCDR1, LCDR2 and LCDR3 of the light chain variable region, wherein the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 determined based on the IMGT protocol respectively comprise or consist of the amino acid sequences shown in the following table SEQ ID NO: or wherein the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 respectively comprises or consists of the amino acid sequence shown in the following table SEQ ID NO:

3. The antibody or antigen-binding fragment thereof that binds to CD105 according to claim 1 or 2, wherein the antibody comprises a heavy chain variable region, wherein the heavy chain variable region comprises, or consists of, an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from the group consisting of SEQ ID NO: 1, 15, 29, 41 or 50; or the heavy chain variable region comprises, or consists of, an amino acid sequence selected from the group consisting of SEQ ID NO: 1, 15, 29, 41 or 50; and / or The antibody comprises a light chain variable region, wherein the light chain variable region comprises an amino acid sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 2, 16, 30, 42 or 51, or consists of said sequence; or the light chain variable region comprises an amino acid sequence selected from SEQ ID NO: 2, 16, 30, 42 or 51, or consists of said sequence.

4. An antibody or antigen-binding fragment thereof that binds to CD105, the antibody comprising a heavy chain variable region and a light chain variable region, wherein a) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO: 1, and The light chain variable region comprises or consists of an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:2; b) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO: 15, and the light chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO: 16; c) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:29, and the light chain variable region comprises an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:30 or consisting of; d) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:41, and the light chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:42; e) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:50, and the light chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:51; f) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 1, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 2; g) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 15, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 16; h) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 29, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 30; i) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:41, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:42; or j) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:50, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:

51.

5. The antibody or antigen-binding fragment thereof that binds to CD105 according to claim 1 or 2, wherein the antibody comprises a heavy chain variable region and a light chain variable region, wherein a) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO: 1, and The light chain variable region comprises or consists of an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:2; b) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO: 15, and the light chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO: 16; c) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:29, and the light chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:30; d) the heavy chain variable region comprises or consists of an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO:41, and the light chain variable region comprises an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence of SEQ ID NO:

42. or consisting of an amino acid sequence with 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity; e) the heavy chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:50, and the light chain variable region comprises or consists of an amino acid sequence that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the amino acid sequence shown in SEQ ID NO:51; f) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 1, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 2; g) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 15, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 16; h) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 29, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 30; i) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:41, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:42; or j) the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:50, and the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:

51.

6. An antibody or antigen-binding fragment thereof that binds to CD105 as described in any one of claims 1 to 5, wherein the antibody comprises a heavy chain constant region, such as a heavy chain constant region of IgG1, IgG2, IgG3, or IgG4, such as a heavy chain constant region of IgG1, for example, (i) comprises an amino acid sequence that is at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:66; or (ii) comprises or consists of the amino acid sequence of SEQ ID NO:

66.

7. An antibody or antigen-binding fragment thereof that binds to CD105 as described in any one of claims 1 to 6, wherein the antibody comprises a light chain constant region, such as a λ or κ light chain constant region, such as the light chain constant region (i) comprises or consists of an amino acid sequence that is at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 67 or 68; or (ii) comprises or consists of an amino acid sequence selected from SEQ ID NO: 67 or 68.

8. The antibody or antigen-binding fragment thereof that binds to CD105 according to any one of claims 1 to 7, wherein the antibody comprises a heavy chain constant region and a light chain constant region, wherein The heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 66; and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 67 or 68.

9. The antibody or antigen-binding fragment thereof that binds to CD105 according to any one of claims 1 to 8, wherein the antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises a heavy chain variable region and a heavy chain constant region or consists of a heavy chain variable region and a light chain variable region, and the light chain comprises a light chain variable region and a light chain constant region or consists of a heavy chain variable region and a light chain variable region, wherein (i) The heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 1, the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 2, and the heavy chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO:

66. or consists of an amino acid sequence of The light chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO:67; (ii). the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 15, the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 16, the heavy chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 68; (iii). the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 29, the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 30, the heavy chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 68; (iv). the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 41, the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO: 42, the heavy chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 66, and the light chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO: 68; or (v). the heavy chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:50, the light chain variable region comprises or consists of the amino acid sequence shown in SEQ ID NO:51, the heavy chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO:66, and the light chain constant region comprises or consists of the amino acid sequence shown in SEQ ID NO:

68.

10. The antibody or antigen-binding fragment thereof that binds to CD105 according to any one of claims 1 to 8, which has one or more of the following characteristics: (1) capable of specifically binding to CD105 with high affinity, such as binding to human or rhesus monkey CD105; (2) can specifically bind to CD105 expressed on the cell membrane surface with high affinity, such as human or rhesus monkey CD105; (3) being able to induce endocytosis of an antibody or a fragment thereof or a molecule comprising the antibody or a fragment thereof (e.g., an immunoconjugate such as ADC) by CD105-positive cells (e.g., CHO cells overexpressing CD105); (4) Ability to target and kill CD105-positive cells, such as CD105-positive tumor cells; (6) capable of treating tumors such as cancer, for example, treating CD105 positive tumors, such as CD105 positive cancers; (7) Suitable for constructing immunoconjugates (e.g., antibody-drug conjugates (ADCs) for targeted killing of CD105-positive cells, such as CD105-positive tumor cells; or for treating tumors such as cancer, such as treating CD105-positive tumors, such as CD105-positive cancers; (8) showing the same or similar binding affinity and / or specificity for CD105 as any of the antibodies listed in claim 9; (9) inhibiting the binding of any antibody listed in claim 9 to CD105; (10) binds to the same or overlapping epitope as any of the antibodies set forth in claim 9; or (11) Competing with any of the antibodies of claim 9 for binding to CD105.

11. The antibody or antigen-binding fragment thereof of any one of claims 1-10, wherein the antibody is a monoclonal antibody.

12. The antibody or antigen-binding fragment thereof of any one of claims 1-11, wherein the antibody is a human antibody.

13. The antibody or antigen-binding fragment thereof of any one of claims 1-12, wherein the antigen-binding fragment is an antibody fragment selected from the group consisting of Fab, Fab', Fab'-SH, Fv, single-chain antibodies such as scFv, (Fab')2 fragments, single domain antibodies, diabodies, or linear antibodies.

14. The antibody or antigen-binding fragment thereof of claim 13, wherein the single-chain antibody is a scFv.

15. The antibody or antigen-binding fragment thereof of claims 1-14, wherein the antibody is a bispecific antibody or a multispecific antibody.

16. An isolated nucleic acid encoding the anti-CD105 antibody or antigen-binding fragment thereof of any one of claims 1 to 15.

17. An expression vector comprising the nucleic acid of claim 16.

18. The expression vector of claim 17, wherein the expression vector is a pCDNA vector, such as a pCDNA3.4 vector.

19. A host cell comprising the nucleic acid of claim 16 or the expression vector of claim 17 or 18.

20. The host cell of claim 19, wherein the host cell is prokaryotic or eukaryotic.

21. The host cell of claim 20, wherein the host cell is selected from Escherichia coli cells, yeast cells, mammalian cells, or other cells suitable for producing antibodies or antigen-binding fragments thereof.

22. The host cell of claim 21, wherein the host cell is a 293 cell or a CHO cell.

23. A method for preparing an anti-CD105 antibody or an antigen-binding fragment thereof, the method comprising culturing the host cell of any one of claims 19-22 under conditions suitable for expressing a nucleic acid encoding the anti-CD105 antibody or antigen-binding fragment thereof of any one of claims 1 to 15, optionally isolating the antibody or antigen-binding fragment thereof, optionally the method further comprising recovering the anti-CD105 antibody or antigen-binding fragment thereof from the host cell.

24. An immunoconjugate comprising the antibody or antigen-binding fragment thereof according to any one of claims 1 to 15 and another therapeutic agent, preferably, the immunoconjugate is an antibody drug conjugate.

25. The immunoconjugate of claim 24, wherein the additional therapeutic agent is a cytotoxic agent, such as MMAE.

26. A pharmaceutical composition comprising the antibody or antigen-binding fragment thereof according to any one of claims 1 to 15 or the immunoconjugate according to claim 24 or 25, and optionally a pharmaceutically acceptable excipient.

27. A pharmaceutical composition comprising the antibody or antigen-binding fragment thereof of any one of claims 1 to 15 or the immunoconjugate of claim 24 or 25, and another therapeutic agent.

28. A pharmaceutical combination comprising the antibody or antigen-binding fragment thereof of any one of claims 1 to 15 or the immunoconjugate of claim 24 or 25, and another therapeutic agent.

29. The pharmaceutical composition of claim 27 or the pharmaceutical combination of claim 28, wherein the other therapeutic agent is selected from a chemotherapeutic agent, a cytokine, a cytotoxic agent, other antibodies, a small molecule drug or an immunomodulator (e.g., an immunosuppressant).

30. Use of an effective amount of an anti-CD105 antibody or antigen-binding fragment thereof according to any one of claims 1 to 15, or an immunoconjugate according to claim 24 or 25, or a pharmaceutical composition according to claim 26 in the preparation of a medicament for preventing or treating a subject or individual tumor in a subject, for example, the tumor is a CD105-positive tumor.

31. The use of any one of claims 30, wherein the tumor is a solid tumor or a blood tumor, for example, the tumor is a cancer, for example, a CD105-positive cancer, for example, the cancer is selected from leukemia (e.g., human myelomonocytic leukemia), thyroid cancer, colorectal cancer, small cell lung cancer, melanoma, prostate cancer, breast cancer, liver cancer, ovarian cancer or gastric cancer, etc.

32. The use of claim 30 or 31, wherein the medicament is also administered to the subject in combination with one or more other therapies.

33. The use of claim 32, wherein the therapy comprises a therapeutic modality and / or other therapeutic agents.

34. The use of claim 33, wherein the other therapeutic agent is selected from a chemotherapeutic agent, a cytokine, other antibodies, a cytotoxic agent, a vaccine, a small molecule drug or an immunomodulator (e.g., an immunosuppressant or activator), and / or the treatment comprises surgery and / or radiotherapy.

35. A method for detecting CD105 in a sample, the method comprising (a) contacting a sample with an antibody or antigen-binding fragment thereof that binds to CD105 according to any one of claims 1 to 15; and (b) detecting the formation of a complex between the anti-CD105 antibody or antigen-binding fragment thereof and CD105; optionally, the anti-CD105 antibody is detectably labeled.

36. A kit comprising the CD105 binding antibody or antigen-binding fragment thereof according to any one of claims 1 to 15.

37. Use of the CD105 binding antibody or antigen-binding fragment thereof according to any one of claims 1 to 15 in the preparation of a kit for diagnosing a CD105-positive tumor (eg, a CD105-positive cancer).

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