WO2022105872A1 - 抗tigit抗体或其抗原结合片段 - Google Patents

抗tigit抗体或其抗原结合片段 Download PDF

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WO2022105872A1
WO2022105872A1 PCT/CN2021/131743 CN2021131743W WO2022105872A1 WO 2022105872 A1 WO2022105872 A1 WO 2022105872A1 CN 2021131743 W CN2021131743 W CN 2021131743W WO 2022105872 A1 WO2022105872 A1 WO 2022105872A1
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seq
antibody
antigen
binding fragment
tigit
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PCT/CN2021/131743
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French (fr)
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芦迪
霍永庭
路力生
韩喆
胡佩佩
涂晶晶
张婵
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广东菲鹏制药股份有限公司
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Priority to JP2023553757A priority Critical patent/JP2023550210A/ja
Priority to EP21894019.5A priority patent/EP4238991A4/en
Priority to US18/038,221 priority patent/US20240002500A1/en
Publication of WO2022105872A1 publication Critical patent/WO2022105872A1/zh

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    • C07K16/28—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
    • C07K16/2803—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily
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    • C07K2317/56—Immunoglobulins specific features characterized by immunoglobulin fragments variable (Fv) region, i.e. VH and/or VL
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    • C07K2317/62—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments comprising only variable region components
    • C07K2317/622—Single chain antibody (scFv)
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    • C07K2317/90—Immunoglobulins specific features characterized by (pharmaco)kinetic aspects or by stability of the immunoglobulin
    • C07K2317/92—Affinity (KD), association rate (Ka), dissociation rate (Kd) or EC50 value
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    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

Definitions

  • the present invention relates to the field of biomedicine, in particular, to an anti-TIGIT antibody or an antigen-binding fragment thereof.
  • TIGIT T cell Ig and ITIM domain, also known as WUCAM, Vstm3, VSIG9 is an ITT domain (immunoglobulin tyrosine tail motif domain) and ITIM domain (immunoreceptor tyrosine inhibitory motif) domain), an inhibitory receptor shared by T cells and NK cells, belonging to the type I transmembrane protein, including the extracellular segment of IgV and the immunoglobulin tyrosine tail-like phosphorylated fragment.
  • the gene was discovered in 2008 by a research group at Genentech.
  • the research group searched the genome for genes that meet specific conditions (1) expressed on immune cells; And find this gene. Through sequence alignment, it was found that this protein belongs to a larger PVR protein family, and its members include activating receptors CD226 and CD96 that compete with TIGIT for ligands, and their ligands PVR, and so on.
  • the crystal structure of TIGIT molecule was analyzed by X-ray diffraction, and it was found that TIGIT expressed on immune cells first formed a cis homodimer on the same cell, and then the dimer passed through a TIGIT molecule on each side.
  • a PVR molecule was bound and a pre-formed homodimer was found to be necessary for the TIGIT-PVR interaction because the TIGIT-PVR interaction would be disrupted if the amino acids of the TIGIT-TIGIT binding interface were pre-mutated.
  • the main ligands of TIGIT are CD155 (Necl-5, PVR poliovirus receptor) and CD112 (PVRL2, Nectin-2).
  • CD155 Necl-5, PVR poliovirus receptor
  • CD112 PVRL2, Nectin-2
  • the binding affinity to CD155 is the highest (3.15nM, Kd)
  • two TIGIT molecules and two CD155 molecules form a tetrameric "lock-and-key structure" (Try113 of TIGIT and AX6G of CD155, Phe128 of CD155 and AX6G of TIGIT respectively form a "key-lock”).
  • These two ligands are also ligands for CD226 (DNAM-1), which competes with TIGIT to stimulate T cell activity.
  • TIGIT The interaction between the ligand and TIGIT defeats CD226, resulting in suppressed immune activity, and tumor cells upregulate CD155 and CD122 to evade immune-mediated destruction. Therefore, antagonistic antibodies specific for TIGIT can inhibit the suppression of CD155 and CD112-induced T cell responses and enhance antitumor immunity.
  • the object of the present invention is to obtain an antibody or an antigen-binding fragment thereof capable of specifically recognizing TIGIT, whose light chain CDR1, CDR2 and CDR3 are selected from SEQ ID NO: 1-3, SEQ ID NO: 4-6, SEQ ID NO: : at least one of 7 ⁇ 9, SEQ ID NO:10 ⁇ 12, SEQ ID NO:13 ⁇ 15, SEQ ID NO:16 ⁇ 18, SEQ ID NO:19 ⁇ 21 combination;
  • CDR1, CDR2, CDR3 are selected from SEQ ID NO:22 ⁇ 24, SEQ ID NO:25 ⁇ 27, SEQ ID NO:28 ⁇ 30, SEQ ID NO:31 ⁇ 33, SEQ ID NO:34 ⁇ 36, At least one of SEQ ID NOs: 37-39 and SEQ ID NOs: 40-42.
  • the present invention also provides nucleic acids, vectors, and cells related to the antibodies or antigen-binding fragments thereof.
  • the present invention also relates to a method for producing an antibody or antigen-binding fragment thereof as described above, comprising:
  • the antibody so produced is recovered from the culture medium or from the cultured cells.
  • the present invention also relates to the use of the above-mentioned antibody or antigen-binding fragment thereof in the preparation of a medicament for the treatment or prevention of infectious diseases, immune diseases or tumors.
  • the present invention also provides a kit comprising at least one of the following components:
  • an antibody or antigen-binding fragment thereof as described above, and optionally a container for holding said antibody or antigen-binding fragment thereof;
  • the above-mentioned antibodies have high affinity for TIGIT and various functional properties, and can be used alone or in combination with other agents for the treatment of cancer, immune and inflammation-related diseases.
  • Fig. 1A, Fig. 1B, Fig. 1C are the verification by flow cytometry (FACS) of Tigit-5, 3Tigit-12, 3Tigit-16, 3Tigit-24, 3Tigit-29, 14Tigit-1-1, The binding affinity of 14Tigit-3-2 to CHO-hTIGIT;
  • Fig. 2A, Fig. 2B, Fig. 2C are the verification of Tigit-5, 3Tigit-16, 3Tigit-24, 3Tigit-29, 14Tigit-1-1, 14Tigit-3- by flow cytometry (FACS) in an embodiment of the present invention.
  • FACS flow cytometry
  • Figure 3A and Figure 3B are flow cytometry (FACS) verification of Tigit-5, 3Tigit-16, 3Tigit-24, 3Tigit-29, 14Tigit-3-2 on CHO-hTIGIT and hPVR-hFc in one embodiment of the present invention The blocking effect of binding;
  • FIG. 4A and FIG. 4B are flow cytometry (FACS) verification of Tigit-5, 3Tigit-16, 3Tigit-24, 3Tigit-29, 14Tigit-1-1, 14Tigit-3-2 on CHO in an embodiment of the present invention - blocking effect of hPVR binding to hTIGIT-hFc;
  • Fig. 5A and Fig. 5B are flow cytometry (FACS) verification of Tigit-5, 3Tigit-16, 3Tigit-24, 3Tigit-29, 14Tigit-1-1, 14Tigit-3-2 on tumors in an embodiment of the present invention
  • FACS flow cytometry
  • Fig. 6A and Fig. 6B are flow cytometry (FACS) verification of Tigit-5, 3Tigit-16, 3Tigit-24, 3Tigit-29, 14Tigit-1-1, 14Tigit-3-2 on CHO in an embodiment of the present invention - blocking effect of CD112 binding to TIGIT;
  • Figure 7A and Figure 7B are flow cytometry (FACS) to verify the binding ability of Tigit-5, 3Tigit-16, 3Tigit-29, 14Tigit-1-1 to cynoTIGIT in one embodiment of the present invention
  • 8A and 8B are verifications of the activation of Tigit-5, 3Tigit-12, 3Tigit-16, and 3Tigit-24 on the killing function of NK92-hTIGIT in one embodiment of the present invention
  • Figure 10A verifies whether different antibodies and R0223 epitopes are the same in one embodiment of the present invention.
  • Figure 10B In one embodiment of the present invention, it is verified whether different antibodies are the same as the R0300 epitope.
  • the present invention relates to an antibody, which binds to an antibody of human TIGIT or an antigen-binding fragment thereof, whose heavy chain CDR1, CDR2 and CDR3 are selected from SEQ ID NO: 1-3, SEQ ID NO: 4-6, SEQ ID NO: 7 ⁇ 9, at least one of SEQ ID NO: 10 ⁇ 12, SEQ ID NO: 13 ⁇ 15, SEQ ID NO: 16 ⁇ 18, SEQ ID NO: 19 ⁇ 21 combination;
  • CDR1, CDR2, CDR3 are selected from SEQ ID NO:22 ⁇ 24, SEQ ID NO:25 ⁇ 27, SEQ ID NO:28 ⁇ 30, SEQ ID NO:31 ⁇ 33, SEQ ID NO:34 ⁇ 36, At least one of SEQ ID NOs: 37-39 and SEQ ID NOs: 40-42.
  • the antibody or antigen-binding fragment thereof has any one of the following combinations of CDR sequences:
  • An important advantage of the antibody or antigen-binding fragment thereof is that it has the activity of blocking the binding of CD112 to TIGIT;
  • An important advantage of the antibody or antigen-binding fragment thereof is that it has the activity of blocking the binding of PVR to TIGIT;
  • An important advantage of the antibody or its antigen-binding fragment is that it has the activity of activating the killing ability of NK92-TIGIT;
  • the antibody or antigen-binding fragment thereof can preferably be used as an antibody drug.
  • the anti-TIGIT antibody or antigen-binding fragment thereof according to the present invention can counteract the inhibitory signal of cancer cells to immune cells through the signaling of TIGIT/CD155 interaction, induce reactivation of immune response to effectively attack cancer cells, thereby providing anti-cancer effects .
  • anti-TIGIT antibodies or antigen-binding fragments thereof can be used for immuno-anticancer therapy targeting TIGIT, a tumor immunosuppressant.
  • an anti-TIGIT antibody or antigen-binding fragment thereof according to the present invention reduces or inhibits the expression or activity of TIGIT in a subject with cancer, and induces a sustained anti-cancer response of T cells or NK cells, thereby providing a therapeutic option for cancer. Effect.
  • antibody or antigen-binding fragment thereof is a protein that binds to a specific antigen, which generally refers to all proteins and protein fragments comprising complementarity determining regions (CDR regions).
  • Antibody specifically refers to a full-length antibody.
  • full-length antibody includes both polyclonal and monoclonal antibodies, and the term “antigen-binding fragment” is a material comprising a portion or all of the CDRs of an antibody that lacks at least some of the amino acids present in the full-length chain but is still capable of specificity bind to antigen.
  • Such fragments are biologically active because they bind to the target antigen and can compete with other antigen-binding molecules, including intact antibodies, for binding to a given epitope.
  • the antigen-binding fragment specifically recognizes and binds to TIGIT.
  • the antigen-binding fragment is a fragment having the function of blocking the binding of CD112 to TIGIT, and/or blocking the binding of PVR to TIGIT, and/or having the function of activating the killing ability of NK92-TIGIT.
  • such fragments will comprise a single heavy chain and a single light chain, or portions thereof.
  • Such fragments can be produced by recombinant nucleic acid techniques, or can be produced by enzymatic or chemical cleavage of antigen-binding molecules, including intact antibodies.
  • CDRs complementarity determining regions
  • CDR and CDRs
  • CDRs are used to refer to the inclusion of one or more or even all of the major amino acids that contribute to the binding affinity of the antibody or antigen-binding fragment thereof to the antigen or epitope it recognizes region of residues.
  • a CDR region or CDR refers to the hypervariable regions of the heavy and light chains of an immunoglobulin as defined by IMGT.
  • the complementarity determining region of the heavy chain is represented by HCDR
  • the complementarity determining region of the light chain is represented by LCDR.
  • Commonly used CDR designation methods in the art include: the Kabat numbering scheme, the Chothia and Lesk numbering scheme, and the new standardized numbering system introduced by Lefranc et al. in 1997 for all protein sequences of the immunoglobulin superfamily. Kabat et al. were the first to propose a standardized numbering scheme for immunoglobulin variable regions.
  • an antibody or antigen-binding fragment thereof binds with an affinity (K D ) of less than about 10-6 M, eg, less than about 10-7 M, 10-8 M, 10-9 M, or 10-10 M or less.
  • the object specifically recognized by the provided antibody or its antigen-binding fragment can be TIGIT derived from various genera, such as human, mouse, monkey (such as cynomolgus monkey).
  • Variants of the antibody or antigen-binding fragment thereof are also within the scope of the invention, such as amino acid or nucleotide sequences each with the respective CDR or FR, or variable region VL and/or VH, or full length of the antibody described herein Sequences having at least 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more than 99% identity.
  • the variant of the antibody or antigen-binding fragment thereof includes at least the 6 CDRs described above; in some cases, the variant of the antibody or antigen-binding fragment thereof includes at least one heavy chain and one light chain, and in other cases , the variant form contains two identical light chains and two identical heavy chains (or sub-portions thereof). In some cases, variants of antibodies or antigen-binding fragments thereof are obtained by conservative modifications or conservative substitutions or substitutions in the sequences of the antibodies or antigen-binding fragments thereof provided herein.
  • Constant modification or “conservative substitution or substitution” refers to the replacement of amino acids in a protein by other amino acids with similar characteristics (eg, charge, side chain size, hydrophobicity/hydrophilicity, backbone conformation and rigidity, etc.) such that frequent Changes are made without altering the biological activity of the protein.
  • Those skilled in the art know that, in general, single amino acid substitutions in non-essential regions of a polypeptide do not substantially alter biological activity (see, e.g., Watson et al. (1987) Molecular Biology of the Gene, The Benjamin/Cummings Pub. Co., 224, (4th ed.). In addition, substitution of structurally or functionally similar amino acids is unlikely to disrupt biological activity.
  • the variants retained the ability to block binding of TIGIT to its ligand CD112 or PVR.
  • Those skilled in the art will be able to determine suitable variants of the antigen binding molecules as elucidated herein using well known techniques. In certain embodiments, those skilled in the art can identify suitable regions of the molecule that can be altered by targeting regions that are believed to be unimportant for activity without disrupting activity.
  • the term "identity" indicates the degree of identity between two nucleic acid or two amino acid sequences when optimally aligned and compared with appropriate insertions or deletions.
  • the antibody or antigen-binding fragment thereof heavy chain FR1, FR2, FR3, FR4 is selected from the group consisting of SEQ ID NO: 43-46, SEQ ID NO: 47-50, SEQ ID NO: 51-54, SEQ ID NO: 43-46, SEQ ID NO: 47-50, At least one of the combinations of ID NO: 55-58, SEQ ID NO: 59-62, SEQ ID NO: 63-66, SEQ ID NO: 67-70;
  • FR1, FR2, FR3, FR4 are selected from SEQ ID NO:71 ⁇ 74, SEQ ID NO:75 ⁇ 78, SEQ ID NO:79 ⁇ 82, SEQ ID NO:83 ⁇ 86, SEQ ID NO:87 ⁇ 90, at least one of SEQ ID NO:91 ⁇ 94, SEQ ID NO:95 ⁇ 98;
  • the antibody or antigen-binding fragment thereof also comprises at least one selected from the following combination of framework region sequences:
  • variable regions of the heavy and light chains are combined in the manner of FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4.
  • variable regions of the heavy and light chains are as described in the above table as Tigit-5, 3Tigit-16, 3Tigit-24, 3Tigit-29, 14Tigit-1-1, 14Tigit-3-2, 3Tigit-
  • the contents of line 12 combine CDRs and FRs in a one-to-one correspondence.
  • the antigen-binding fragment is any one of Fab, F(ab')2, Fd, Fv, scFv, bispecific antibody and antibody minimal recognition unit, preferably F(ab') 2 , Fab , scFv and one of bispecific antibodies.
  • the antibody has a constant region, and the heavy chain constant region sequence is selected from the constant region sequence of any one of IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgE, and IgD; the light chain constant region is kappa or lambda chain.
  • the species source of the constant region is selected from the group consisting of bovine, equine, porcine, sheep, goat, rat, mouse, dog, cat, rabbit, camel, donkey, deer, mink, chicken, duck, goose or man.
  • the present invention also relates to nucleic acids encoding antibodies or antigen-binding fragments thereof as described above.
  • the nucleic acid is usually RNA or DNA, and the nucleic acid molecule can be single-stranded or double-stranded, but is preferably double-stranded DNA.
  • a nucleic acid is "operably linked" when it is placed in a functional relationship with another nucleic acid sequence.
  • a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the coding sequence.
  • DNA nucleic acid is preferably used when it is ligated into a vector.
  • nucleic acids typically carry a signal peptide sequence.
  • the present invention also relates to a vector comprising a nucleic acid as described above.
  • vector refers to a nucleic acid delivery vehicle into which a polynucleotide can be inserted.
  • the vector can express the protein encoded by the inserted polynucleotide, the vector is called an expression vector.
  • the vector can be introduced into a host cell by transformation, transduction or transfection, so that the genetic material elements carried by it can be expressed in the host cell.
  • Vectors are well known to those skilled in the art and include, but are not limited to: plasmids; phagemids; cosmids; artificial chromosomes, such as yeast artificial chromosomes (YACs), bacterial artificial chromosomes (BACs) or P1 derived artificial chromosomes (PACs) ; Phage such as ⁇ phage or M13 phage and animal viruses.
  • YACs yeast artificial chromosomes
  • BACs bacterial artificial chromosomes
  • PACs P1 derived artificial chromosomes
  • Animal viruses that can be used as vectors include, but are not limited to, retroviruses (including lentiviruses), adenoviruses, adeno-associated viruses, herpesviruses (eg, herpes simplex virus), poxviruses, baculoviruses, papillomaviruses, papillomaviruses Polyoma vacuolar virus (eg SV40).
  • the vectors of the present invention contain regulatory elements commonly used in genetic engineering, such as enhancers, promoters, internal ribosome entry sites (IRES), and other expression control elements (such as transcription termination signals, or multiple adenylation signals and poly U sequences, etc.).
  • the present invention also provides cells comprising a nucleic acid as described above or a vector as described above.
  • the expressions "cell”, “cell line” and “cell culture” are used interchangeably and all such designations include progeny.
  • the words “transformants” and “transformed cells” include primary test cells and cultures derived therefrom, regardless of the number of transfers. It should also be understood that, due to deliberate or unintentional mutations, all progeny may not be exactly the same in terms of DNA content. Mutant progeny that have the same function or biological activity as screened in the original transformed cell are included. Where a different name is meant, it is clear from the context.
  • Suitable host cells or cell lines for expressing the antigen binding proteins of the invention include mammalian cells such as NSO, Sp2/0, CHO, COS, HEK, fibroblasts and myeloma cells. Human cells can be used, thus allowing molecules to be modified with human glycosylation patterns. Alternatively, other eukaryotic cell lines can be employed. The selection of suitable mammalian host cells, as well as methods for transformation, culture, amplification, screening, and product production and purification, are known in the art.
  • Bacterial cells may prove useful as host cells suitable for expressing the recombinant Fab or other embodiments of the invention. However, since proteins expressed in bacterial cells tend to be in unfolded or incorrectly folded or non-glycosylated forms, any recombinant Fab produced in bacterial cells must be screened for retention of antigen binding capacity.
  • a bacterial cell would be the desired host if the molecule expressed by the bacterial cell is produced in a properly folded form, or, in an alternative embodiment, the molecule can be expressed in a bacterial host and subsequently refolded.
  • the various E. coli strains used for expression are well-known host cells in the field of biotechnology. Various strains of Bacillus subtilis, Streptomyces sp, other Bacillus sp., etc., can also be used in this method.
  • yeast cell strains known to those skilled in the art, as well as insect cells, such as Drosophila and Lepidopteran and viral expression systems, can also be used as host cells.
  • the antibody or antigen-binding fragment thereof so produced is recovered from the culture medium or from the cultured cells.
  • a common method for producing antibodies or antigen-binding fragments thereof involves culturing the cells, eg, hybridomas, in vitro, and collecting the antibody or antigen-binding fragment thereof from the supernatant.
  • the cells are transplanted into immunodeficient animals (eg, nude mice), and purified antibodies or antigen-binding fragments thereof are collected from the animal's serum and other locations.
  • immunodeficient animals eg, nude mice
  • purified antibodies or antigen-binding fragments thereof are collected from the animal's serum and other locations.
  • the present invention also provides pharmaceutical compositions comprising the antibody or antigen-binding fragment thereof as described above, and one or more of a pharmaceutically acceptable excipient, diluent or carrier.
  • pharmaceutically acceptable excipient, diluent or carrier refers to an excipient, diluent or carrier that is pharmacologically and/or physiologically compatible with the subject and the active ingredient.
  • the present invention also relates to the use of the above-mentioned antibody or antigen-binding fragment thereof in the preparation of a medicament for the treatment or prevention of infectious diseases, immune diseases or tumors.
  • the present invention also relates to a kit comprising at least one of the following components:
  • an antibody or antigen-binding fragment thereof as described above, and optionally a container for holding said antibody or antigen-binding fragment thereof;
  • the present invention also relates to a method of treating a disease in a subject comprising administering to the subject an effective amount of an antibody or antigen-binding fragment thereof as described above, optionally in combination with another therapeutic agent or therapeutic procedure joint;
  • the disease is selected from infectious disease, immune disease or tumor.
  • the subject is an animal.
  • the subject is a mammal.
  • the subject is a primate.
  • the subject is a human.
  • Anti-human TIGIT monoclonal antibody is produced based on conventional hybridoma technology. The specific process is as follows:
  • Immunizations were performed using soluble human TIGIT fusion protein prepared in-house or commercially procured (AcroBiosystems, Catalog #TIT-H5253) as antigen.
  • the antigen was prepared in-house.
  • the human TIGIT extracellular segment was selected, the mouse mIgG2a-Fc fragment was fused at its C-terminus, and the standard recombinant protein expression technology was used for transient expression in HEK293 cells.
  • Affinity chromatography column purification to obtain the target protein, sterilized and filtered, aliquoted to -80 °C and frozen for later use.
  • mice with human TIGIT-mFc protein were immunized with human TIGIT-mFc protein as described previously.
  • Human TIGIT-mFc protein was injected intraperitoneally or subcutaneously into immunized mice, the dosage: 25 ⁇ g/100 ⁇ L, 1 injection per week, generally a total of 6 injections; or 50 ⁇ g/100 ⁇ L, 1 injection every two weeks, generally a total of 5 injections, specific immunization
  • the number of needles is related to the actual immune effect of each mouse. Generally, the mice with good immune effect go to the next steps in advance, and the mice with poor immune effect continue to be immunized.
  • the immunization effect is judged by monitoring the serum titer of mice. Generally, after 3 injections of immunization, the binding ability (ie titer) of mouse serum to antigen is detected by ELISA method. Mice with the highest titer were selected for booster immunization, 50 ⁇ g of antigen was injected through the spleen, and the booster immunization was ready for fusion 3 days later.
  • mouse spleen was taken and isolated by conventional techniques to obtain mouse spleen cells.
  • the mouse tumor cells SP2/0 and immune spleen cells were mixed at a ratio of 1:10 cells and transferred to a 50ml centrifuge tube, washed once with RPMI1640 basal medium . Discard the supernatant, mix the cells, and slowly add 1 ml of 50% PEG1500 for fusion. After 1 min of fusion, 15 ml of RPMI1640 basal medium was added to stop cell fusion. Centrifuge at 1000 rpm for 5 min and discard the supernatant.
  • Fusion detection Dilute the recombinant human TIGIT protein with human Fc tag (in-house preparation) with 0.05M carbonate buffer to a final concentration of 2 ⁇ g/ml, add 100 ⁇ l/well to a 96-well ELISA detection plate, and incubate at 37°C for 2h or 2- Coat overnight at 4°C. The supernatant was discarded, and after washing 5 times with plate washing solution (1 ⁇ PBS), 200 ⁇ l/well of blocking solution (1 ⁇ PBS+1%BSA) was added, and the cells were blocked at 37° C. for 1 h. On the 7th day after recombination and fusion, 100 ⁇ l/well of cell supernatant was added, and incubated at 37°C for 30 min.
  • Positive subclone detection Dilute the human TIGIT recombinant protein (in-house preparation) carrying human Fc tag with 0.05M carbonate buffer to a final concentration of 2 ⁇ g/ml, add 100 ⁇ l/well to a 96-well ELISA test plate, and incubate at 37°C for 2h Or coat overnight at 2-4°C. The supernatant was discarded, and after washing 5 times with plate washing solution (1 ⁇ PBS), 200 ⁇ l/well of blocking solution (1 ⁇ PBS+1%BSA) was added, and the cells were blocked at 37° C. for 1 h. 100 ⁇ l/well of subcloning supernatant was added and incubated at 37°C for 30 min. Wash 3 times with 1x PBS.
  • the cells When the clone producing anti-human TIGIT antibody grows to 80% confluence, the cells are blown off, centrifuged at 1000 rpm for 5 min, resuspended in 30 ml of SFM complete medium containing 5% FBS, and transferred to a 150 ml SF shake flask , 37°C, 8% CO 2 , 120rpm for 2-3 days.
  • the process is as follows, using an AKTA york 150 chromatography equipment, equilibrate the column (such as MabSelectSuRe LX, GE) with at least 5CV of equilibration buffer (10mM PBS), load the sample onto the column, and allow the target protein to adsorb on the column and Other impurities penetrate and separate.
  • equilibration buffer 10mM PBS
  • equilibration buffer 10mM PBS
  • neutralization buffer 1M Tris, pH 8.0
  • the device detects the absorbance value of the sample, and calculates the concentration of the antibody to be tested according to the Lambert-Beer law.
  • ultrafiltration concentration tube Ultra-15Centrifugal Filter Devices, 30kD
  • concentrate the sample concentration to >0.5mg/ml collect the concentrated sample, sterilize and filter it with a 0.22um sterile syringe filter (Cobaxter, PES, 0.22um) , 13mm in diameter), then subpackage and freeze for later use;
  • HRP-labeled goat anti-mouse IgG (sigma A0168-1ML), HRP-labeled goat anti-mouse IgG2a (thermo fisher M32207), HRP-labeled goat anti-mouse IgG1 (thermo fisher PA1-74421), HRP-labeled goat anti-mouse IgG1 (thermo fisher PA1-74421), HRP-labeled Goat anti-mouse IgG2b (thermo fisher M32407), HRP-labeled goat anti-mouse IgG3 (thermo fisher M32607), HRP-labeled goat anti-mouse IgM (thermo fisher 31440), incubate at 37°C for 30 minutes, and wash three times with 1 ⁇ PBS Then, after the color reaction was carried out, the data was read on the microplate reader using OD450/OD630nm.
  • the CHO engineering cells CHO-hTIGIT cells to be tested recombinantly expressing full-length human TIGIT were counted, centrifuged at 300 g for 5 min, resuspended in FCM buffer, and the cell density was adjusted to 4E+06 cells/mL for use.
  • R0223 was derived from 22G2IgG1.1f in patent WO2016106302 (A1), and R0223-CH1 was the Fc region of mIgG1 that replaced the Fc region of R0223.
  • R0300 is derived from tiragolumab in patent WO2017053748 (A2), and R0300 is the Fc region of mIgG1 replaced by the Fc region.
  • R0223 and R0300 were used as screening control antibodies.
  • the healthy human PBMC peripheral blood mononuclear cells
  • FCM buffer to dilute the test sample (including positive control antibody, mouse monoclonal antibody) to 20 ⁇ g/mL, and then use FCM buffer for 3-fold serial dilution to 12 concentration points; use FCM buffer to dilute the isotype control antibody to 20 ⁇ g/mL.
  • the CHO engineering cells CHO-hTIGIT cells to be tested recombinantly expressing full-length human TIGIT were counted, centrifuged at 300 g for 5 min, resuspended in FCM buffer, and the cell density was adjusted to 4E+06 cells/mL for use.
  • FCM buffer to dilute the test sample (including positive control antibody, mouse monoclonal antibody) to 20 ⁇ g/mL, and then use FCM buffer for 3-fold serial dilution to 12 concentration points; use FCM buffer to dilute the ligand protein hPVR-hFc to 20 ⁇ g /mL; use FCM buffer to dilute the isotype control antibody to 20 ⁇ g/mL.
  • 50 ⁇ L of antibody and 50 ⁇ L of cells were added to each well of the 96-well V-plate (the amount of each cell line added to the 96-well V-plate was 2E+05 cells/well), and incubated on ice for 30 min in the dark.
  • secondary antibody PE anti-human IgG Fc, 1:500 dilution
  • the U2-OS cells to be detected (human osteosarcoma cells, which naturally highly express PVR and CD112) were counted, centrifuged at 300 g for 5 min, resuspended in FCM buffer, and adjusted to a cell density of 4E+06 cells/mL for later use.
  • FCM buffer to dilute the test sample (including positive control antibody, mouse monoclonal antibody) to 20 ⁇ g/mL, and then use FCM buffer for 3-fold serial dilution to 12 concentration points; use FCM buffer to dilute the antigen protein hTIGIT-hFc to 120 ⁇ g/mL mL; use FCM buffer to dilute the isotype control antibody to 20 ⁇ g/mL.
  • 50 ⁇ L of antigenic protein and 50 ⁇ L of cells were added to each well of the 96-well V-plate (the amount of each cell line added to the 96-well V-plate was 2E+05 cells/well), and incubated on ice for 30 min in the dark.
  • Add secondary antibody (APC anti-human IgG Fc, 1:500 dilution) to 96-well V-plate (according to 100 ⁇ L/well), and incubate on ice for 30 min in the dark.
  • the CHO engineering cells CHO-hCD112 cells to be tested recombinantly expressing full-length human CD112 were counted, centrifuged at 300 g for 5 min, resuspended in FCM buffer, and adjusted to 4E+06 cells/mL for cell density.
  • FCM buffer to dilute the test sample (including positive control antibody, mouse monoclonal antibody) to 20 ⁇ g/mL, and then use FCM buffer for 3-fold serial dilution to 12 concentration points; use FCM buffer to dilute the antigen protein hTIGIT-hFc to 120 ⁇ g/mL mL; use FCM buffer to dilute the isotype control antibody to 20 ⁇ g/mL.
  • 50 ⁇ L of antigenic protein and 50 ⁇ L of cells were added to each well of the 96-well V-plate (the amount of each cell line added to the 96-well V-plate was 2E+05 cells/well), and incubated on ice for 30 min in the dark.
  • Add secondary antibody (APC anti-human IgG Fc, 1:500 dilution) to 96-well V-plate (according to 100 ⁇ L/well), and incubate on ice for 30 min in the dark.
  • the mouse mAb obtained through screening can relatively better bind to CHO-hTIGIT and healthy human PBMC, and can relatively better block CHO-hTIGIT, CHO-hPVR, CHO-hCD112, US-OS and other cells. Binding of TIGIT receptor to ligand PVR (CHO-hPVR blocks the binding of PVR ligand to receptor TIGIT on cells).
  • the CHO engineering cells CHO-cynoTIGIT cells that recombinantly express full-length cynoTIGIT to be tested were counted, centrifuged at 300 g for 5 min, resuspended in FCM buffer, and the cell density was adjusted to 4E+06 cells/mL for later use.
  • the MD ForteBIO QKe platform was used to analyze the binding kinetics constant of anti-hTigit antibody to hTigit.
  • the experimental method was as follows: the recombinant protein hTigit-his (self-produced) carrying the his-tagged human Tigit extracellular domain was diluted with equilibration buffer (1 ⁇ PBS+0.02% Tween 20) to a final concentration of 3 ⁇ g/ml.
  • the anti-hTigit antibody was diluted 2-fold with equilibration buffer (1 ⁇ PBS+0.02% Tween 20), the initial concentration was 10 ⁇ g/ml, and there were 7 concentrations in total.
  • the anti-Penta-HIS biosensor FormeBIO, Cat.
  • Antibody name KD, ⁇ 10E- 10 (M) R0300-CH1 0.631 Tigit-5 0.605 3Tigit-12 1.19 3Tigit-16 2.02 3Tigit-24 1.93 3Tigit-29 1.55 14Tigit-1-1 1.72 14Tigit-3-2 0.627
  • Agilent Bio-RTCA SP is used to detect the ability of mouse monoclonal antibody to activate the killing function of NK cells.
  • the ability of mouse monoclonal antibody to activate NK cells is achieved by blocking the combination of TIGIT on the surface of NK cells and PVR on the surface of target cells.
  • the specific experimental procedure is as follows. First, 50 ⁇ L/well of 1640 medium was added to the 96-well plate to be tested, and the instrument was automatically calibrated; the subcultured U2OS cells (naturally highly expressed PVR) were digested with TE buffer, and the cell suspension obtained by digestion was digested with 1640 Count after medium resuspend:
  • the cell suspension was adjusted to 2 ⁇ 10 5 cells/mL with 1640 medium according to the required number of cells, and then the cells were added to the experimental well plate at a volume of 50 ⁇ L/well. After standing in a biological safety cabinet for 15 min, Plates plated with cells were placed in the apparatus and incubated overnight. After 20 hours, after U2OS was close to the bottom of the cell plate, the preparation of antibodies and NK92-hTIGIT cells (recombinantly expressing hTIGIT) was started. The subcultured NK92-TIGIT cells were blown into a single cell suspension, resuspended in 1640 medium and counted:
  • NK92-TIGIT-1640 1.3 ⁇ 105/mL 45.98% 12.32 ⁇ m
  • NK92-TIGIT cells Take the above cell suspension, adjust the number of NK92-TIGIT cells to 1 ⁇ 10 5 cells/mL; at the same time, dilute the mouse monoclonal antibody to be tested to the required concentration, and then according to the experimental design, the antibody and NK92-TIGIT cells were respectively treated with The volume of 50 ⁇ L/well was added to the corresponding well plate, and the blank group was supplemented with the corresponding volume of 1640 medium. Place the cell culture plate in a biosafety cabinet for 30 minutes, while adjusting the instrument parameters for normalization; continue to put the culture plate into the detection card slot, continue to culture and record in the incubator.
  • the cells were mixed with 10 mL of PBS, centrifuged at 400 g/5 min and the supernatant was removed.
  • the cells were resuspended in 2 mL, and 2 ⁇ L of CFSE was added to stain the cells at 37°C for 15 min.
  • the number of cells was adjusted to 2 x 105 /mL with culture medium and added to a 96-well plate in a volume of 100 [mu]L (60 wells in the middle, and the edges were sealed with 100 [mu]L of PBS). Continue to culture cells for 20h.
  • NK92-TIGIT cells were prepared. Dilute the antibody to be tested and isotype hIgG1 to four times the desired concentration. The subcultured NK92-TIGIT cells were blown into a single cell suspension, resuspended at 1640 and counted. The above cell suspension was taken, and the number of NK92-TIGIT cells was adjusted to 4 ⁇ 10 5 cells/mL. According to the experimental design, the antibody and NK92-TIGIT cells were added to the corresponding well plates at a volume of 50 ⁇ L/well, respectively, and the blank group was supplemented with a corresponding volume of 1640 medium. Continue to grow in the incubator.
  • GraphPad Prism 5 software take the antibody concentration as the abscissa and the calculated relative killing efficiency Cytotoxicity (%) as the ordinate to perform nonlinear fitting to calculate the EC 50 value.
  • Epitope competition analysis of anti-human Tigit antibody was performed using the MD ForteBIO QKe platform.
  • the experimental method is as follows, the recombinant protein hTigit-his (Acrobiosystem, Cat.TIT-H2H3, lot-1336-76GF1-F9) carrying his-tagged human Tigit extracellular domain was diluted with equilibration buffer (1 ⁇ PBS+0.02% Tween 20). ) to a final concentration of 1.5 ⁇ g/ml.
  • Anti-human Tigit antibody was diluted in equilibration buffer (1 x PBS + 0.02% Tween 20) to a final concentration of 5 ⁇ g/ml.
  • the anti-Penta-HIS biosensor FormeBIO, Cat.
  • one anti-human Tigit antibody (9Tigit-45) was epitope different from R0223.
  • 15 anti-human Tigit antibodies Tigit-5, Tigit-17, Tigit-18, Tigit-22, 3Tigit-2, 3Tigit-14, 3Tigit-21-1, 3Tigit-21-2, 3Tigit-22, 3Tigit-33 , 3Tigit-41, 3Tigit-56, 9Tigit-17, 9Tigit-21, 9Tigit-45) are different from the R0300 epitope.
  • the first antibody includes anti-human Tigit antibody, reference antibodies R0223-CH1, R0300-CH1 (mIgG1 subtype) and mIgG1 isotype control antibody at a concentration of 10 ⁇ g/ml
  • the second antibody includes reference antibody R0223, R0300 (hlgG1 isotype), hIgG1 isotype control antibody, its concentration is 1 ⁇ g/ml.
  • the fluorescent secondary antibody was a PE-labeled goat anti-human Fc fluorescent secondary antibody (dilution ratio of 1:500) (Biolegend, Cat. 409304).
  • the results are consistent with step 1 in Example 7, and one anti-human Tigit antibody has a different epitope from R0223.
  • the 15 anti-human Tigit antibodies differed from the R0300 epitope, and R0223 overlapped with the R0300 epitope.
  • the antibody sequence involved in the present invention is as follows:
  • the CDR sequences are underlined, the FR sequences are not underlined, and the numbers in parentheses represent the sequence numbers.
  • VH sequence of Tigit-5 mouse mAb VH sequence of Tigit-5 mouse mAb:
  • VL sequence of Tigit-5 mouse mAb VL sequence of Tigit-5 mouse mAb:
  • VL sequence of 3Tigit-16 mouse mAb VL sequence of 3Tigit-16 mouse mAb:
  • VL sequence of 3Tigit-24 mouse mAb VL sequence of 3Tigit-24 mouse mAb:
  • VH sequence of 14Tigit-1-1 mouse mAb VH sequence of 14Tigit-1-1 mouse mAb:
  • VL sequence of 14Tigit-1-1 mouse mAb VL sequence of 14Tigit-1-1 mouse mAb:
  • VH sequence of 14Tigit-3-2 mouse mAb VH sequence of 14Tigit-3-2 mouse mAb:
  • VL sequence of 14Tigit-3-2 mouse mAb VL sequence of 14Tigit-3-2 mouse mAb:

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Abstract

提供了一种抗TIGIT抗体或其抗原结合片段。该抗体或其抗原结合片段具有与TIGIT具有较高的亲和力，且具有多方面的功能特性，可单独或与其它试剂组合用于治疗癌症、免疫及炎症相关疾病。

Description

抗TIGIT抗体或其抗原结合片段 技术领域
本发明涉及生物医药领域，具体而言，涉及一种抗TIGIT抗体或其抗原结合片段。
背景技术
TIGIT(T cell Ig and ITIM domain，也称为WUCAM，Vstm3，VSIG9)是含ITT结构域(免疫球蛋白酪氨酸尾部基序结构域)及ITIM结构域(免疫受体酪氨酸抑制基序结构域)的T细胞和NK细胞共有的抑制性受体，属于I型跨膜蛋白，包括IgV胞外段以及免疫球蛋白酪氨酸尾巴样磷酸化片段。
该基因在2008年由Genentech公司的研究组发现。该研究组通过在基因组中搜索符合特定条件(①表达在免疫细胞上；②属于I型跨膜蛋白；③胞外带有免疫球蛋白结构域；④胞内带有免疫调节结构域)的基因而寻找到这个基因。通过序列比对，发现这个蛋白隶属于一个较大的PVR蛋白家族，其成员包括与TIGIT竞争配体的活化型受体CD226和CD96，以及它们的配体PVR，等等。2012年，TIGIT分子的晶体结构通过X射线衍射得到解析，研究发现免疫细胞上表达的TIGIT首先形成同一细胞上的顺式同源二聚体，然后该二聚体各通过一侧的一个TIGIT分子结合一个PVR分子，并且发现预先形成的同源二聚体对于TIGIT-PVR相互作用是必须的，因为如果预先将TIGIT-TIGIT结合界面的氨基酸进行突变，则TIGIT-PVR的相互作用会被破坏。
TIGIT的主要配体为CD155(Necl-5，PVR脊髓灰质炎病毒受体)以及CD112(PVRL2，Nectin-2)。其中又以与CD155的结合亲和力最高(3.15nM，Kd)，两个TIGIT分子与两个CD155分子形成四聚体“锁钥结构”(TIGIT的Try113与CD155的AX6G，以及CD155的Phe128和TIGIT的AX6G分别形成“钥-锁”)。这两个配体同时也是CD226(DNAM-1)的配体，CD226与TIGIT竞争，刺激T细胞活性。配体与TIGIT之间的相互作用打败了CD226，使免疫活性受到抑制，肿瘤细胞上调CD155和CD122以逃避免疫介导的破坏作用。因此，对TIGIT具有特异性的拮抗性抗体可抑制CD155和CDl 12诱导的T细胞反应的抑制且增强抗肿瘤免疫。
发明内容
本发明的目标是获得一种能够特异性识别TIGIT的抗体或其抗原结合片段，其轻链CDR1、CDR2、CDR3选自SEQ ID NO:1～3、SEQ ID NO:4～6、SEQ ID NO:7～9、SEQ ID NO:10～12、SEQ ID NO:13～15、SEQ ID NO:16～18、SEQ ID NO:19～21组合中的至少一种；
其重链CDR1、CDR2、CDR3选自SEQ ID NO:22～24、SEQ ID NO:25～27、SEQ ID NO:28～30、SEQ ID NO:31～33、SEQ ID NO:34～36、SEQ ID NO:37～39、SEQ ID NO:40～42中的至少一种。
本发明还提供所述抗体或其抗原结合片段相关的核酸、载体、细胞。
本发明还涉及一种生产如上所述的抗体或其抗原结合片段的方法，包括：
在培养基中培养如上所述的细胞；以及
从培养基中或从所培养的细胞中回收如此产生的抗体。
根据本发明的再一方面，还涉及如上所述的抗体或其抗原结合片段在制备用于治疗或预防感染性疾病、 免疫性疾病或肿瘤的药物中的应用。
本发明还提供试剂盒，其包含下述成分中的至少一种：
i)如上所述的抗体或其抗原结合片段，以及任选的用于承装所述抗体或其抗原结合片段的容器；
ii)如上所述的药物组合物，以及任选的用于承装所述药物组合物的容器。
上述抗体具有与TIGIT具有较高的亲和力，且具有多方面的功能特性，可单独或与其它试剂组合用于治疗癌症、免疫及炎症相关疾病。
附图说明
为了更清楚地说明本发明具体实施方式或现有技术中的技术方案，下面将对具体实施方式或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1A、图1B、图1C为本发明一个实施例中通过流式细胞术(FACS)验证Tigit-5、3Tigit-12、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2等对CHO-hTIGIT的结合亲和力；
图2A、图2B、图2C为本发明一个实施例中通过流式细胞术(FACS)验证Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2对健康人PBMC的结合亲和力；
图3A、图3B为本发明一个实施例中通过流式细胞术(FACS)验证Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-3-2对CHO-hTIGIT与hPVR-hFc结合的阻断效果；
图4A、图4B为本发明一个实施例中通过流式细胞术(FACS)验证Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2对CHO-hPVR与hTIGIT-hFc结合的阻断效果；
图5A、图5B为本发明一个实施例中通过流式细胞术(FACS)验证Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2对肿瘤细胞与TIGIT结合的阻断效果；
图6A、图6B为本发明一个实施例中通过流式细胞术(FACS)验证Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2对CHO-CD112与TIGIT结合的阻断效果；
图7A、图7B为本发明一个实施例中通过流式细胞术(FACS)验证Tigit-5、3Tigit-16、3Tigit-29、14Tigit-1-1与cynoTIGIT结合能力；
图8A、图8B为本发明一个实施例中Tigit-5、3Tigit-12、3Tigit-16、3Tigit-24对NK92-hTIGIT杀伤功能的活化作用验证；
图9为本发明一个实施例中Tigit-5、3Tigit-16活化NK92-hTIGIT杀伤U2-OS能力验证；
图10A本发明一个实施例中验证不同抗体与R0223表位是否相同；
图10B本发明一个实施例中验证不同抗体与R0300表位是否相同。
具体实施方式
现将详细地提供本发明实施方式的参考，其一个或多个实例描述于下文。提供每一实例作为解释而非限制本发明。实际上，对本领域技术人员而言，显而易见的是，可以对本发明进行多种修改和变化而不背离本发明的范围或精神。例如，作为一个实施方式的部分而说明或描述的特征可以用于另一实施方式中， 来产生更进一步的实施方式。
因此，旨在本发明覆盖落入所附权利要求的范围及其等同范围中的此类修改和变化。本发明的其它对象、特征和方面公开于以下详细描述中或从中是显而易见的。本领域普通技术人员应理解本讨论仅是示例性实施方式的描述，而非意在限制本发明更广阔的方面。
本发明涉及一种抗体，其结合人TIGIT的抗体或其抗原结合片段，其重链CDR1、CDR2、CDR3选自SEQ ID NO:1～3、SEQ ID NO:4～6、SEQ ID NO:7～9、SEQ ID NO:10～12、SEQ ID NO:13～15、SEQ ID NO:16～18、SEQ ID NO:19～21组合中的至少一种；
其轻链CDR1、CDR2、CDR3选自SEQ ID NO:22～24、SEQ ID NO:25～27、SEQ ID NO:28～30、SEQ ID NO:31～33、SEQ ID NO:34～36、SEQ ID NO:37～39、SEQ ID NO:40～42中的至少一种。
在一些实施方式中，所述抗体或其抗原结合片段具有选自如下CDR序列组合中的任一种：
Figure PCTCN2021131743-appb-000001
该抗体或其抗原结合片段的一个重要优点在于其与TIGIT具有较高的亲和力。
该抗体或其抗原结合片段的一个重要优点在于其具有阻断CD112与TIGIT结合的活性；
该抗体或其抗原结合片段的一个重要优点在于其具有阻断PVR与TIGIT结合的活性；
该抗体或其抗原结合片段的一个重要优点在于其具有活化NK92-TIGIT杀伤能力的活性；
该抗体或其抗原结合片段的一个重要优点在于其与TIGIT的结合表位是新的。
因具有上述特性，该抗体或其抗原结合片段优选可作为抗体药物使用。
根据本发明的抗TIGIT抗体或其抗原结合片段能够通过TIGIT/CD155相互作用的信号传递以抵消癌细胞对免疫细胞的抑制信号，诱导免疫应答的再激活以有效攻击癌细胞，从而提供抗癌作用。最终，抗TIGIT抗体或其抗原结合片段可用于靶向TIGIT(一种肿瘤免疫抑制剂)的免疫抗癌疗法。特别地，根据本发明的抗TIGIT抗体或其抗原结合片段降低或抑制患有癌症的受试者中TIGIT的表达或活性，并诱导T细胞或NK细胞的持续抗癌反应，从而提供治疗癌症的效果。
在本发明中，“抗体或其抗原结合片段”此技术术语是结合特定抗原的蛋白，其泛指包含互补决定区(CDR区)的一切蛋白及蛋白片段。“抗体”特别指全长抗体。“全长抗体”此用语包括多克隆抗体及单克隆抗体，术语“抗原结合片段”是包含抗体CDR的一部分或全部的物质，其缺乏至少一些存在于全长链中的氨基酸但仍能够特异性结合至抗原。此类片段具生物活性，因为其结合至靶抗原，且可与其他抗原结合分 子(包括完整抗体)竞争结合至给定表位。在一些实施方式中，抗原结合片段具有特异性识别并结合TIGIT的作用。在一些实施方式中，抗原结合片段是具有阻断CD112与TIGIT结合，和/或阻断PVR与TIGIT结合，和/或具有活化NK92-TIGIT杀伤能力功能的片段。在一个方面中，此类片段将包含单个重链和单个轻链，或其部分。所述片段可通过重组核酸技术产生，或可通过抗原结合分子(包括完整抗体)的酶裂解或化学裂解产生。
术语“互补性决定区”或“CDR”是指免疫球蛋白的重链和轻链的高度可变区。有三种重链CDR和三种轻链CDR。此处，取决于情况，术语“CDR”和“CDRs”用于指包含一种或多种或者甚至全部的对抗体或其抗原结合片段与其识别的抗原或表位的结合亲和力起作用的主要氨基酸残基的区域。在另一具体实施方式中，CDR区或CDR是指IMGT定义的免疫球蛋白的重链和轻链的高度可变区。
在本发明中，重链的互补决定区用HCDR表示，轻链的互补决定区用LCDR表示。本领域常用的CDR标示方法包括：Kabat编号方案、Chothia和Lesk编号方案以及1997年Lefranc等人为免疫球蛋白超家族的所有蛋白质序列引入的新的标准化编号系统。Kabat等人是第一个为免疫球蛋白可变区提出标准化编号方案的人。在他们的“免疫学蛋白质序列”(Sequences of Proteins of Immunological Interest)的汇编中，轻链(λ，κ)可变区和抗体重链的氨基酸序列，以及T细胞受体的可变区(α，β，γ，δ)对齐并编号。在过去的几十年中，序列的积累导致了KABATMAN数据库的创建，Kabat编号方案通常被认为是编号抗体残基广泛采用的标准。本发明采用Kabat注释标准标示CDR区，但其他方法标示的CDR区也属于本发明的保护范围。
术语“特异性识别”、“选择性结合”、“选择性地结合”和“特异性地结合”或其类似表述是指抗体或其抗原结合片段对预先确定的抗原上的表位的结合。通常，抗体或其抗原结合片段以大约小于10 -6M，例如大约小于10 -7M、10 -8M、10 -9M或10 -10M或更小的亲和力(K D)结合。
在本发明中，所提供的抗体或其抗原结合片段特异性识别的对象可以为多种属来源的TIGIT，例如人、小鼠、猴(如食蟹猴cynomolgus monkey)。
抗体或其抗原结合片段的变体也在本发明范围内，例如各自与本发明所述的各个CDR或FR、或可变区VL和/或VH、或抗体全长的氨基酸或核苷酸序列具有至少70％、80％、85％、90％、91％、92％、93％、94％、95％、96％、97％、98％、99％或高于99％同一性的序列。在一些情况下，抗体或其抗原结合片段的变体至少包括上述6个CDR；在一些情况下，抗体或其抗原结合片段的变体至少包括一个重链和一个轻链，而在其他情况下，变体形式含有两个相同的轻链和两个相同的重链(或其子部分)。在一些情况下，抗体或其抗原结合片段的变体是在本发明所提供的抗体或其抗原结合片段序列上发生保守修饰或保守置换或取代所得到的。“保守修饰”或“保守置换或取代”是指具有类似特征(例如电荷、侧链大小、疏水性/亲水性、主链构象和刚性等)的其它氨基酸置换蛋白中的氨基酸，使得可频繁进行改变而不改变蛋白的生物学活性。本领域技术人员知晓，一般而言，多肽的非必需区域中的单个氨基酸置换基本上不改变生物学活性(参见例如Watson等(1987)Molecular Biology of the Gene,The Benjamin/Cummings Pub.Co.,第224页，(第4版))。另外，结构或功能类似的氨基酸的置换不大可能破环生物学活性。在一些情况下，变体保留阻断TIGIT与其配体CD112或PVR结合的能力。所属领域技术人员将能够使用熟知的技术确定如本文所阐明的抗原结合分子的合适变体。在某些实施方案中，所属领域技术人员可鉴别分子的可通过靶据信对于活性而言不重要的区来改变而不破坏活性的合适区域。对于核苷酸和氨基酸序列，术语“同一性”表明当具有适当的插入或缺失的情况下最佳比对和比较时两个核酸或两个氨基酸序列之间的同一性程度。
在一些实施方式中，所述抗体或其抗原结合片段重链FR1、FR2、FR3、FR4选自SEQ ID NO:43～46、SEQ ID NO:47～50、SEQ ID NO:51～54、SEQ ID NO:55～58、SEQ ID NO:59～62、SEQ ID NO:63～66、SEQ ID NO:67～70组合中的至少一种；
其轻链FR1、FR2、FR3、FR4选自SEQ ID NO:71～74、SEQ ID NO:75～78、SEQ ID NO:79～82、SEQ  ID NO:83～86、SEQ ID NO:87～90、SEQ ID NO:91～94、SEQ ID NO:95～98中的至少一种；
可选地，所述抗体或其抗原结合片段还包含选自如下骨架区序列组合中的至少一种：
Figure PCTCN2021131743-appb-000002
重链和轻链的可变区按照FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4的方式组合得到。
在优选的实施方式中，重链和轻链的可变区按照上述表格中Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2、3Tigit-12行中的内容将CDR和FR一一对应进行组合。
在一些实施方式中，所述抗原结合片段为Fab、F(ab’)2、Fd、Fv、scFv、双特异抗体和抗体最小识别单位中的任一种，优选F(ab’) 2、Fab、scFv以及双特异抗体中的一种。
在一些实施方式中，所述抗体具有恒定区，重链恒定区序列选自IgG1、IgG2、IgG3、IgG4、IgA、IgM、IgE、IgD任意一种的恒定区序列；轻链恒定区为κ或λ链。
在一些实施方式中，所述恒定区的种属来源选自牛、马、猪、绵羊、山羊、大鼠、小鼠、狗、猫、兔、骆驼、驴、鹿、貂、鸡、鸭、鹅或人。
本发明还涉及核酸，其编码如上所述的抗体或其抗原结合片段。
核酸通常是RNA或DNA，核酸分子可以是单链或双链的，但优选是双链DNA。当将核酸与另一个核酸序列置于功能关系中时，核酸是“有效连接的”。例如，如果启动子或增强子影响编码序列的转录，那么启动子或增强子有效地连接至所述编码序列。当其连入载体时优选采用DNA核酸。
此外，鉴于抗体为膜蛋白，所以核酸通常带有信号肽序列。
本发明还涉及载体，其包含如上所述的的核酸。
术语“载体(vector)”是指，可将多聚核苷酸插入其中的一种核酸运载工具。当载体能使插入的多核苷酸编码的蛋白获得表达时，载体称为表达载体。载体可以通过转化，转导或者转染导入宿主细胞，使其携带的遗传物质元件在宿主细胞中获得表达。载体是本领域技术人员公知的，包括但不限于：质粒；噬菌粒；柯斯质粒；人工染色体，例如酵母人工染色体(YAC)、细菌人工染色体(BAC)或P1来源的人工染色体(PAC)；噬菌体如λ噬菌体或M13噬菌体及动物病毒等。可用作载体的动物病毒包括但不限于，逆转录酶病毒(包括慢病毒)、腺病毒、腺相关病毒、疱疹病毒(如单纯疱疹病毒)、痘病毒、杆状病毒、乳头瘤病毒、乳头多瘤空泡病毒(如SV40)。在一些实施方式中，本发明所述载体中包含基因工程中常用的调控元件，例如增强子、启动子、内部核糖体进入位点(IRES)和其他表达控制元件(例如转录终止信号，或者多腺苷酸化信号和多聚U序列等)。
本发明还提供细胞，其包含如上所述的核酸或如上所述的载体。
本文使用的表述“细胞”、“细胞系”和“细胞培养物”可互换使用，并且所有这类名称都包括后代。因此， 单词“转化体”和“转化细胞”包括原代受试细胞和由其衍生的培养物，而不考虑转移数目。还应当理解的是，由于故意或非有意的突变，所有后代在DNA含量方面不可能精确相同。包括具有与最初转化细胞中筛选的相同的功能或生物学活性的突变后代。在意指不同名称的情况下，其由上下文清楚可见。
适用于表达本发明的抗原结合蛋白的宿主细胞或细胞系包括：哺乳动物细胞诸如NS0、Sp2/0、CHO、COS、HEK、成纤维细胞和骨髓瘤细胞。可以使用人细胞，因而允许分子用人糖基化模式来修饰。或者，可以采用其他真核细胞系。合适的哺乳动物宿主细胞的选择，以及用于转化、培养、扩增、筛选和产物产生和纯化的方法，是本领域已知的。
可以证明，细菌细胞可用作宿主细胞，其适合表达本发明的重组Fab或其他实施方案。但是，由于在细菌细胞中表达的蛋白倾向于未折叠的形式或不正确地折叠的形式或非糖基化形式，必须筛选在细菌细胞中产生的任何重组Fab，以保留抗原结合能力。如果细菌细胞表达的分子以适当地折叠的形式产生，该细菌细胞将是期望的宿主，或者，在可替代的实施方案中，可以在细菌宿主中表达分子，然后随后进行重新折叠。例如，用于表达的各种大肠杆菌菌株，是生物技术领域中众所周知的宿主细胞。枯草芽孢杆菌、链霉菌属、其他芽孢杆菌属等的各种菌株，也可以用于该方法中。
如果需要，本领域技术人员已知的酵母细胞菌株以及昆虫细胞，例如果蝇和鳞翅目昆虫和病毒表达系统，也可用作宿主细胞。
根据本发明的再一方面，还涉及一种生产如上所述的抗体或其抗原结合片段的方法，包括：
在合适的培养条件下培养如上所述的细胞；以及
从培养基中或从所培养的细胞中回收如此产生的抗体或其抗原结合片段。
常见的生产抗体或其抗原结合片段的方法包括体外培养所述的细胞例如杂交瘤，并从上清中收集抗体或其抗原结合片段。
或者将所述细胞移入免疫缺陷动物(例如裸鼠)中，再从动物的血清等位置收集纯化抗体或其抗原结合片段。
本发明还提供药物组合物，其包括如上所述的抗体或其抗原结合片段，以及药学上可接受的赋形剂、稀释剂或载体中的一种或多种。
术语“药学上可接受的赋形剂、稀释剂或载体”是指在药理学和/或生理学上与受试者和活性成分相容的赋形剂、稀释剂或载体。
根据本发明的再一方面，本发明还涉及如上所述的抗体或其抗原结合片段在制备用于治疗或预防感染性疾病、免疫性疾病或肿瘤的药物中的应用。
本发明还涉及试剂盒，其包含下述成分中的至少一种：
i)如上所述的抗体或其抗原结合片段，以及任选的用于承装所述抗体或其抗原结合片段的容器；
ii)如上所述的药物组合物，以及任选的用于承装所述药物组合物的容器。
另外，本发明还涉及治疗受试者的疾病的方法，其包括向所述受试者施用有效量的如上所述的抗体或其抗原结合片段，其任选地与另一治疗剂或治疗程序联合；
所述疾病选自感染性疾病、免疫性疾病或肿瘤。
在一些实施方式中，所述受试者为动物。
在一些实施方式中，所述受试者为哺乳动物。
在一些实施方式中，所述受试者为灵长类动物。
在一些实施方式中，所述受试者为人。
术语“任选地”仅用于描述目的，而不能理解为指示或暗示相对重要性。由此，限定有“任选地”的特征可以明示或者隐含地包括或不包括该特征。
下面将结合实施例对本发明的实施方案进行详细描述。
实施例1抗人TIGIT抗体生成及制备
基于常规杂交瘤技术产生抗人TIGIT单克隆抗体，具体流程如下：
1.抗原制备：
使用内部制备或商业化采购(AcroBiosystems,Catalog#TIT-H5253)的可溶人TIGIT融合蛋白作为抗原 进行免疫。
内部制备抗原选取人TIGIT胞外段，在其C端融合小鼠mIgG2a-Fc片段，采用标准的重组蛋白表达技术在HEK293细胞中进行瞬转表达，收集所述细胞分泌表达上清，使用蛋白A亲和层析柱纯化获得目标蛋白，除菌过滤后分装至-80℃冻存备用。
2.小鼠免疫：
为了产生抗人TIGIT单克隆抗体，取6-10周龄的Balb/c母鼠用前面所述人TIGIT-mFc蛋白进行免疫。人TIGIT-mFc蛋白通过腹腔或皮下注入免疫小鼠，使用剂量：25μg/100μL，每周1针一般共免疫6针；或50μg/100μL，每两周1针一般共免疫5针，具体的免疫针数与每支小鼠的实际免疫效果有关，一般免疫效果好的小鼠提前进行后续步骤，免疫效果不好的小鼠则继续进行免疫。免疫效果通过监测小鼠血清效价判断，一般在免疫3针后，通过ELISA方法检测小鼠血清对抗原的结合能力(即效价)。选取最高效价的小鼠进行加强免疫，使用50μg抗原通过脾脏注入，加强免疫3天后准备融合。
3.杂交瘤融合：
使用常规技术取小鼠脾脏并分离得到小鼠脾细胞，将小鼠瘤细胞SP2/0与免疫脾细胞按照1:10细胞数量比例混合并转移至50ml离心管中，用RPMI1640基础培养基洗涤一次。弃上清，将细胞混匀，缓慢加入1ml 50％PEG1500融合。融合1min后，加入15ml RPMI1640基础培养基终止细胞融合。1000rpm离心5min，弃上清。用50ml RPMI1640筛选培养基轻轻混悬，平分于96孔板中，共10块，50μl/孔，37℃、5％CO 2细胞培养箱静置培养。培养至第六天，更换HT培养基(含HT的RPMI1640完全培养基)两次。
融合检测：用0.05M碳酸缓冲液稀释携带人Fc标签的人TIGIT重组蛋白(内部制备)至终浓度为2μg/ml，按100μl/孔加入96孔ELISA检测板中，37℃孵育2h或2-4℃包被过夜。弃上清，使用洗板液(1×PBS)清洗5次后，按200μl/孔加入封闭液(1×PBS+1％BSA)，37℃封闭1h。重组融合后第7天，按100μl/孔加入细胞上清，37℃静置孵育30min。用1×PBS洗涤3次。按100μl/孔加入HRP标记的羊抗鼠IgG(sigma A0168-1ML)，37℃静置孵育30min，用1×PBS洗涤3次后，进行显色反应后，于酶标仪采用OD450/OD630nm读取数据。挑选OD450nm-OD630nm≥1.0的融合子，采用有限稀释法进行克隆化，至少2次。
阳性亚克隆检测：采用用0.05M碳酸缓冲液稀释携带人Fc标签的人TIGIT重组蛋白(内部制备)至终浓度为2μg/ml，按100μl/孔加入96孔ELISA检测板中，37℃孵育2h或2-4℃包被过夜。弃上清，使用洗板液(1×PBS)清洗5次后，按200μl/孔加入封闭液(1×PBS+1％BSA)，37℃封闭1h。按100μl/孔加入亚克隆上清液，37℃静置孵育30min。用1×PBS洗涤3次。按100μl/孔加入HRP标记的羊抗鼠IgG(sigma A0168-1ML)，37℃静置孵育30min，用1×PBS洗涤3次后，进行显色反应后，于酶标仪采用OD450/OD630nm读取数据。所得的阳性亚克隆经体外培养进行保种和表达。
4.鼠单抗表达及纯化：
待产生抗人TIGIT抗体的克隆生长至汇合率至80％时，将细胞吹落，1000rpm离心5min后，用30ml含5％FBS的SFM完全培养基重悬细胞，并转移至150ml SF摇瓶中，37℃，8％CO 2，120rpm培养2-3天。当细胞密度达到5×10E5/ml时，1000rpm离心5min，用50ml无血清的SFM基础培养基重悬细胞，并转移至250ml SF摇瓶中，37℃，8％CO 2，120rpm培养4-5天，9000rpm离心20min，收集上清进行纯化。纯化采用ProA亲和层析。过程如下，使用AKTA avant 150层析设备，用至少5CV平衡缓冲液(10mM PBS)平衡层析柱(如MabSelectSuRe LX，GE)，加载样品至层析柱，使目标蛋白吸附在层析柱上而其他杂质穿透分离。完成上样后使用至少5CV平衡缓冲液(10mM PBS)再次冲洗层析柱，随后使用洗脱缓冲液(20mM NaAc，pH＝3.4)洗脱目标蛋白，收集管中预先加入中和缓冲液(1M Tris，pH8.0)，中和缓冲液的加入体积根据洗脱样品的预估含量而定，一般加入10％洗脱体积量。
样品使用Biotek-Epoch-Take-3进行浓度测定，利用A280方法检测抗体浓度，即以消光系数E.C.＝1.37，光程＝0.05mm(Take-3板不同孔光程有细微差异，会自动校正)，通过设备检测样品吸光值，按照Lambert-Beer law计算待测抗体的浓度。样品浓度过低则需要进行超滤浓缩，使用超滤浓缩管(
Figure PCTCN2021131743-appb-000003
Ultra-15Centrifugal Filter Devices，30kD)按照说明书提供的通用操作方法，将样品浓度浓缩至＞0.5mg/ml；收集浓缩端样品，0.22um无菌针头滤器除菌过滤(科百特，PES，0.22um，直径13mm)后分装冻存备用；
5.鼠单抗亚型鉴定：
用0.05M pH9.5碳酸缓冲溶液稀释携带人Fc标签重组人TIGIT重组蛋白(内部制备)，使其终浓度为2μg/mL，按100μl/孔加入96孔ELISA检测板中，37℃孵育2h或2-4℃包被过夜。弃上清，使用洗板液(1×PBS)清洗5次后，按200μl/孔加入封闭液(1×PBS+1％BSA)，37℃封闭1h。用含1％BSA的1×PBS稀释抗体至1μg/ml，按100μl/孔加入上述获得抗人TIGIT鼠单抗，37℃孵育30分钟。用1×PBS洗涤3次。按100μl/孔加入HRP标记的羊抗鼠IgG(sigma A0168-1ML)、HRP标记的羊抗鼠IgG2a(thermo fisher M32207)、HRP标记的羊抗鼠IgG1(thermo fisher PA1-74421)、HRP标记的羊抗鼠IgG2b(thermo fisher M32407)、HRP标记的羊抗鼠IgG3(thermo fisher M32607)、HRP标记的羊抗鼠IgM(thermo fisher 31440)，37℃静置孵育30min，用1×PBS洗涤3次后，进行显色反应后，于酶标仪采用OD450/OD630nm读取数据。
实施例2抗TIGIT抗体结合阻断筛选
1.鼠单抗结合CHO-hTIGIT能力检测：
将待检测的重组表达全长人TIGIT的CHO工程细胞CHO-hTIGIT细胞进行细胞计数，300g离心5min，FCM buffer重悬，调整细胞密度至4E+06个/mL备用。使用FCM buffer将待测样品(包括阳性对照抗体、鼠单抗)稀释至20μg/mL，然后使用FCM buffer进行3倍系列稀释12个浓度点；使用FCM buffer将同型对照抗体稀释至20μg/mL。按照实验设计分别96孔V型板每孔加入50μL抗体和50μL细胞(每株细胞加入到96孔V型板中的量为2E+05个/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入二抗(PE Goat anti-mouse IgG,1:500稀释)至96孔V型板(按照100μL/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入100μL 1×PBS重悬，上机检测。
结果分析，R0223来源于专利WO2016106302(A1)中22G2IgG1.1f，R0223-CH1是将R0223的Fc区替换为mIgG1的Fc区。R0300来源于专利WO2017053748(A2)中tiragolumab，R0300是将Fc区替换为mIgG1的Fc区。R0223、R0300作为筛选对照抗体，由图1A、图1B、图1C结果可知，Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2对CHO-hTIGIT的结合亲和力好于对照抗体。
2.鼠单抗结合健康人PBMC能力检测：
为了验证我们制备的抗人TIGIT抗体能够有效结合天然表达TIGIT能力，专门进行了一下实验。将待检测的健康人PBMC(外周血单核细胞)细胞进行细胞计数，300g离心5min，FCM buffer重悬，调整细胞密度至4E+06个/mL备用。使用FCM buffer将待测样品(包括阳性对照抗体、鼠单抗)稀释至20μg/mL，然后使用FCM buffer进行3倍系列稀释12个浓度点；使用FCM buffer将同型对照抗体稀释至20μg/mL。按照实验设计分别96孔V型板每孔加入50μL抗体和50μL细胞(每株细胞加入到96孔V型板中的量为2E+05个/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入二抗(PE Goat anti-mouse IgG,1:500稀释)至96孔V型板(按照100μL/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入100μL 1×PBS重悬，上机检测。
结果分析，由图2a、图2b、图2c结果可知，Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2对健康人PBMC的结合亲和力好于对照抗体。
3.鼠单抗阻断CHO-hTIGIT与hPVR-hFc结合能力检测：
为了验证抗人TIGIT抗体能够阻断CHO-hTIGIT与hPVR-hFc结合能力，专门进行以下实验。将待检测的重组表达全长人TIGIT的CHO工程细胞CHO-hTIGIT细胞进行细胞计数，300g离心5min，FCM buffer重悬，调整细胞密度至4E+06个/mL备用。使用FCM buffer将待测样品(包括阳性对照抗体、鼠单抗)稀释至20μg/mL，然后使用FCM buffer进行3倍系列稀释12个浓度点；使用FCM buffer将配体蛋白hPVR-hFc稀释至20μg/mL；使用FCM buffer将同型对照抗体稀释至20μg/mL。按照实验设计分别96孔V型板每孔加入50μL抗体和50μL细胞(每株细胞加入到96孔V型板中的量为2E+05个/孔)，冰上避光孵育30min。加入配体蛋白至96孔V型板(按照50μL/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入二抗(PE anti-human IgG Fc,1:500稀释)至96孔V型板(按照100μL/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加 入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入100μL 1×PBS重悬，上机检测。
结果分析，由图3A、图3B结果可知，Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-3-2能够很好的阻断CHO-hTIGIT与hPVR-hFc的结合，并且阻断效果要好于对照抗体。
4.鼠单抗阻断CHO-hPVR与hTIGIT-hFc结合能力检测：
为了验证抗人TIGIT抗体能够阻断CHO-hPVR与hTIGIT-hFc结合能力，专门进行以下实验。使用FCM buffer将待测样品(包括阳性对照抗体、鼠单抗)稀释至40μg/mL，然后使用FCM buffer进行3倍系列稀释12个浓度点；使用FCM buffer将抗原蛋白hTIGIT-hFc稀释至0.6μg/mL；使用FCM buffer将同型对照抗体稀释至40μg/mL。加入待测抗体和抗原蛋白hTIGIT-hFc至96孔V型板(抗体和抗原分别按照50μL/孔加入)冰上避光孵育30min。将待检测的重组表达全长人PVR的CHO工程细胞CHO-hPVR细胞进行细胞计数，300g离心5min，FCM buffer重悬，加入细胞至96孔V型板，每株细胞加入到96孔V型板中的量为2E+05个/孔(按照50μL/孔加入)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入二抗(PE anti-human IgG Fc,1:500稀释)至96孔V型板(按照100μL/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入100μL 1×PBS重悬，上机检测。
结果分析，由图4A、图4B结果可知，Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2能够很好的阻断CHO-hPVR与hTIGIT-hFc的结合，并且阻断效果要好于对照抗体
5.鼠单抗阻断天然肿瘤细胞结合hTIGIT-hFc能力检测
为了验证抗人TIGIT抗体能够阻断天然肿瘤细胞表达hPVR与hTIGIT-hFc结合能力，专门进行以下实验。将待检测的U2-OS细胞(人骨肉瘤细胞，经检测天然高表达PVR、CD112)进行细胞计数，300g离心5min，FCM buffer重悬，调整细胞密度至4E+06个/mL备用。使用FCM buffer将待测样品(包括阳性对照抗体、鼠单抗)稀释至20μg/mL，然后使用FCM buffer进行3倍系列稀释12个浓度点；使用FCM buffer将抗原蛋白hTIGIT-hFc稀释至120μg/mL；使用FCM buffer将同型对照抗体稀释至20μg/mL。按照实验设计分别96孔V型板每孔加入50μL抗原蛋白和50μL细胞(每株细胞加入到96孔V型板中的量为2E+05个/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入抗体至96孔V型板(按照100μL/孔加入)冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入二抗(APC anti-human IgG Fc,1:500稀释)至96孔V型板(按照100μL/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入100μL 1×PBS重悬，上机检测。
结果分析，由图5A、图5B结果可知，Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2能够很好的阻断肿瘤细胞与TIGIT的结合，并且阻断效果要好于对照抗体
6.鼠单抗阻断CHO-hCD112与hTIGIT-hFc结合能力检测
为了验证抗人TIGIT抗体能够阻断CHO-hCD112与hTIGIT-hFc结合能力，专门进行以下实验。将待检测的重组表达全长人CD112的CHO工程细胞CHO-hCD112细胞进行细胞计数，300g离心5min，FCM buffer重悬，调整细胞密度至4E+06个/mL备用。使用FCM buffer将待测样品(包括阳性对照抗体、鼠单抗)稀释至20μg/mL，然后使用FCM buffer进行3倍系列稀释12个浓度点；使用FCM buffer将抗原蛋白hTIGIT-hFc稀释至120μg/mL；使用FCM buffer将同型对照抗体稀释至20μg/mL。按照实验设计分别96孔V型板每孔加入50μL抗原蛋白和50μL细胞(每株细胞加入到96孔V型板中的量为2E+05个/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入抗体至96孔V型板(按照100μL/孔加入)冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入二抗(APC anti-human IgG Fc,1:500稀释)至96孔V型板(按照100μL/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入100μL 1×PBS重悬，上机检测。
结果分析，由图6A、图6B结果可知，Tigit-5、3Tigit-16、3Tigit-24、3Tigit-29、14Tigit-1-1、14Tigit-3-2能够很好的阻断CHO-CD112与TIGIT的结合，并且阻断效果要好于对照抗体。
综上，通过筛选获得的鼠单抗可以相对更好的结合CHO-hTIGIT、健康人PBMC，并且能够相对更好 的阻断CHO-hTIGIT、CHO-hPVR、CHO-hCD112、US-OS等细胞上TIGIT受体与配体PVR的结合(CHO-hPVR是阻断细胞上PVR配体与受体TIGIT的结合)。
实施例3抗人TIGIT抗体种属交叉结合能力
鼠单抗结合CHO-cynoTIGIT能力检测：
为了验证抗人TIGIT抗体与猴TIGIT结合能力，专门进行以下实验。将待检测的重组表达全长cynoTIGIT的CHO工程细胞CHO-cynoTIGIT细胞进行细胞计数，300g离心5min，FCM buffer重悬，调整细胞密度至4E+06个/mL备用。使用FCM buffer将待测样品(包括阳性对照抗体、鼠单抗)稀释至20μg/mL，然后使用FCM buffer进行3倍系列稀释12个浓度点；使用FCM buffer将同型对照抗体稀释至20μg/mL。按照实验设计分别96孔V型板每孔加入50μL抗体和50μL细胞(每株细胞加入到96孔V型板中的量为2E+05个/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入二抗(PE Goat anti-mouse IgG,1:500稀释)至96孔V型板(按照100μL/孔)，冰上避光孵育30min。离心(300g/5min)，弃上清，加入200μL FCM buffer洗涤一次，离心(300g/5min)，弃上清。加入100μL 1×PBS重悬，上机检测。
结果分析，由图7A、图7B结果可知，Tigit-5、3Tigit-16、3Tigit-29、14Tigit-1-1能够很好的与cynoTIGIT结合，并且结合效果要好于对照抗体。
实施例4抗人Tigit抗体结合动力学KD分析
采用MD ForteBIO QKe平台进行抗hTigit抗体与hTigit的结合动力学常数分析。实验方法如下，用平衡缓冲液(1×PBS+0.02％吐温20)稀释携带his标签的人Tigit胞外区重组蛋白hTigit-his(自产)至终浓度为3μg/ml。用平衡缓冲液(1×PBS+0.02％吐温20)2倍倍比稀释抗hTigit抗体，起始浓度为10μg/ml，共7个浓度。待anti-Penta-HIS生物传感器(ForteBIO，Cat.18-5122)充分水化后，先固化hTigit-his重组蛋白120秒，平衡90秒后，与抗hTigit抗体结合，其中结合时间为300秒，解离时间为600秒。整个反应在25℃，1000rpm条件下进行。最后用Octet分析软件进行曲线拟合，获得抗hTigit抗体的结合动力学常数KD。
如表1所示，抗人Tigit抗体与人Tigit重组蛋白的结合动力学常数均在pM级别。
表1
抗体名称 KD，×10E -10(M)
R0300-CH1 0.631
Tigit-5 0.605
3Tigit-12 1.19
3Tigit-16 2.02
3Tigit-24 1.93
3Tigit-29 1.55
14Tigit-1-1 1.72
14Tigit-3-2 0.627
实施例5抗TIGIT抗体活化NK细胞功能实验
利用96孔实时无标记细胞分析仪对前述抗体进行体外功能筛选。大部分的细胞检测方法采用的是传统的终点法,仅仅给出最终结果，而且往往需要标记细胞和破坏细胞。这些方法无法得到细胞在生长时的真正状态，也无法对细胞的生长过程做出动态的监测和分析。实时无标记细胞分析仪使用一种非侵入式的方法，记录细胞的实时生长状态。这种成像方法，被称为“实时细胞内涵成像”(Live ContentImaging)，扩充了实验过程中记录和理解细胞生长、细胞行为和细胞形态的途径。
本实施例利用安捷伦生物RTCA SP检测鼠单抗活化NK细胞杀伤功能的能力，鼠单抗活化NK细胞能力是通过阻断NK细胞表面TIGIT与靶细胞表面的PVR结合而达成的。具体实验流程如下。首先在需要做实验的96孔板中加入50μL/孔的1640培养基，进行仪器自动校正阶段；传代培养的U2OS细胞(天然高表达PVR)用TE缓冲液消化，消化得到的细胞悬液用1640培养基重悬后计数：
U2OS-P4T2-1640 7.31×10 5个/mL 99.14％16.07μm
根据所需要的细胞数量用1640培养基将细胞悬液调整至2×10 5个/mL，然后将细胞以50μL/孔的体积加入到实验孔板中，在生物安全柜中静置15min后，将铺有细胞的孔板放置在仪器中，培养过夜。20h后，U2OS紧贴细胞板底部后，开始准备抗体和NK92-hTIGIT细胞(重组表达hTIGIT)。将传代培养的NK92-TIGIT细胞吹散成单细胞悬液，1640培养基重悬后计数：
NK92-TIGIT-1640 1.3×10 5个/mL 45.98％12.32μm
取上述细胞悬液，将NK92-TIGIT细胞调整数量至1×10 5个/mL；同时将待检测的鼠单抗稀释到所需要的浓度，然后按照实验设计将抗体和NK92-TIGIT细胞分别以50μL/孔的体积加入到对应的孔板中，空白组补上相应体积的1640培养基。将细胞培养板放置在生物安全柜中静置30min，同时调整仪器参数归一化处理；继续把培养板放入检测卡槽内，在培养箱中继续培养并记录。
观察仪器中参数cell index至bottom值后停止实验，分析数据，并按照下面公式计算细胞杀伤率：
Cytotoxicity＝(index E+T-index Exp)/index E+T×100％
以时间为X轴，杀伤效率为Y轴作图。
结果分析，由图8A、图8B结果可知，鼠单抗均有较好的活化NK92-hTIGIT杀伤能力，其中Tigit-5、3Tigit-12、3Tigit-16、3Tigit-24对NK92-hTIGIT杀伤功能的活化作用明显好于对照样品。
实施例6抗TIGIT抗体活化NK细胞杀伤功能实验
利用双荧光法进一步检测抗TIGIT抗体活化NK细胞杀伤功能：
靶细胞铺板
TE消化培养的细胞U2OS计数，取实验足量的细胞。将细胞用PBS 10mL混匀，400g/5min离心后去上清。用2mL重悬细胞，加入2μL CFSE染色细胞37℃15min。补加8mL的PBS重悬细胞。400g/5min离心细胞后用10mL的PBS再次重悬细胞。400g/5min离心，弃上清，用合适的的10％FBS 1640培养基重悬细胞。细胞再次计数。用培养基调整细胞数量到2×10 5/mL，以100μL的体积加入到96孔板中(中间60孔，边缘用100μL PBS封上)。继续培养细胞20h。
加入效应细胞和抗体
20h后，U2OS紧贴细胞板底部后，开始准备抗体和NK92-TIGIT细胞。将待检测抗体和isotype hIgG1稀释到所需要浓度的四倍。将传代培养的NK92-TIGIT细胞吹散成单细胞悬液，1640重悬后计数。取上述细胞悬液，将NK92-TIGIT细胞调整数量至4×10 5个/mL。按照实验设计将抗体和NK92-TIGIT细胞分别以50μL/孔的体积加入到对应的孔板中，空白组补上相应体积的1640培养基。继续在培养箱中培养。
流式检测
16h后取出96孔板，将细胞上清转移到另一个96孔板中，注意一一对应，往其中加入35μL的PBS清洗板底，并将清洗液转移到对应的96孔板中。往96孔板中每孔加入35μL的0.25％Trypsin-EDTA，至于37℃培养箱中约5min。将之前的96板中的液体一一对应的转移到现在消化完毕的96孔板中，终止消化，轻轻吹散细胞。加入每孔10μL的PI溶液，使其终浓度为1μg/mL，轻轻混匀(记得立即上机检测，时间不要超过45min为宜)。流式细胞仪分析各孔细胞。
数据分析
CFSE和PI双阳性细胞为被杀伤细胞，CFSE单阳性细胞认为是所有靶细胞总和。因此抗体的绝对杀伤效率即为Cytotoxicity＝(PI和CFSE双阳性细胞数)/(CFSE单阳性细胞数)×100％；先计算每个加入抗体组的不同浓度的实验孔Cytotoxicity(％)，以T+E孔为阴性对照孔；再计算相对的细胞杀伤效率＝(实验组-对照孔)/对照孔×100％。用GraphPad Prism 5软件以抗体浓度作为横坐标，以计算出来的相对杀伤效率Cytotoxicity(％)的值作为纵坐标进行非线性拟合，计算EC 50值。
结果分析，由图9结果可知，Tigit-5、3Tigit-16能够活化NK92-hTIGIT杀伤U2-OS能力，并且其活化作用要明显好于对照样品。
实施例7抗人Tigit抗体竞争表位分析
1.epitope binning
采用MD ForteBIO QKe平台进行抗人Tigit抗体的表位竞争分析。实验方法如下，用平衡缓冲液 (1×PBS+0.02％吐温20)稀释携带his标签的人Tigit胞外区重组蛋白hTigit-his(Acrobiosystem,Cat.TIT-H2H3，lot-1336-76GF1-F9)至终浓度为1.5μg/ml。用平衡缓冲液(1×PBS+0.02％吐温20)稀释抗人Tigit抗体，其终浓度为5μg/ml。待anti-Penta-HIS生物传感器(ForteBIO，Cat.18-5122)充分水化后，先固化hTigit-his重组蛋白180秒，平衡30秒后，与第一种抗人Tigit抗体结合180秒，平衡30秒后，再与第二种抗人Tigit抗体结合其中结合时间为300秒。整个反应在25℃，1000rpm条件下进行。最后用Octet分析软件进行epitope binning分析。
如表2和表3所示，1株抗人Tigit抗体(9Tigit-45)与R0223表位不同。15株抗人Tigit抗体(Tigit-5、Tigit-17、Tigit-18、Tigit-22、3Tigit-2、3Tigit-14、3Tigit-21-1、3Tigit-21-2、3Tigit-22、3Tigit-33、3Tigit-41、3Tigit-56、9Tigit-17、9Tigit-21、9Tigit-45)与R0300表位不同。
表2
Tigit-5 Tigit-17 Tigit-18 Tigit-22 3Tigit-2 3Tigit-3 3Tigit-9
0.0443 0.047 0.0383 0.0353 0.0118 0.0105 0.0165
3Tigit-12 3Tigit-14 3Tigit-16 3Tigit-21-1 3Tigit-21-2 3Tigit-22 3Tigit-24
0.01 0.0126 0.008 0.0133 0.0206 0.0583 0.0379
3Tigit-29 3Tigit-33 3Tigit-41 3Tigit-48 3Tigit-49 3Tigit-51 3Tigit-52
-0.0018 0.0225/0.059 0.0108 0.0153 0.0413 0.0613 0.0307
3Tigit-56 6Tigit-10 8Tigit-4 8Tigit-7 9Tigit-17 9Tigit-21 9Tigit-30
0.0323 0.0341 0.026 0.0148 0.0395 0.0504 0.0537
9Tigit-31 9Tigit-45 R0223        
0.0484 0.3347 0.0566        
表3
Figure PCTCN2021131743-appb-000004
2.流式分析细胞水平的抗体表位竞争
用1×FCM缓冲液(1×FBS+3％BSA)稀释抗Tigit抗体，其中第一种抗体包括对标抗体R0223、R0300(hIgG1亚型)、hIgG1同型对照抗体，其浓度为10μg/ml，第二种抗体包括抗人Tigit抗体、对标抗体R0223-CH1、R0300-CH1(mIgG1亚型)和mIgG1同型对照抗体，其浓度为1μg/ml。用1×FCM缓冲液重悬重组表达人Tigit的CHO稳定细胞株，调整细胞密度为2×10E6/ml，按100μl/孔分于96孔板中。250×g离心5min后，吸弃上清，加入第一种抗体100μl，冰上孵育30min后，加入第二种抗体100μl，冰上孵育30min。250×g离心5min后，吸弃上清。用1×FCM洗涤2次后，按100μl/孔加入用1×FCM缓冲液稀释的PE标记的羊抗鼠Fc荧光二抗(稀释倍数为1:500)(Biolegend，Cat.405307)，冰上孵育30min。250×g离心5min后，吸弃上清，加入1×FCM洗涤2次后，按100μl/孔加入1×PBS重悬细胞，采用流式细胞仪(Beckman，cytoFLEX)进行检测。反之，第一种抗体包括抗人Tigit抗体、对标抗体R0223-CH1、R0300-CH1(mIgG1亚型)和mIgG1同型对照抗体，其浓度为10μg/ml，第二种抗体包括对标抗体R0223、R0300(hIgG1亚型)、hIgG1同型对照抗体，其浓度为1μg/ml。荧光二抗为PE标记的羊抗人Fc荧光二抗(稀释倍数为1:500)(Biolegend，Cat.409304)。
如图10A、图10B所示，结果与实施例7中的步骤1一致，1株抗人Tigit抗体与R0223表位不同。15株抗人Tigit抗体与R0300表位不同，并且R0223与R0300表位有重叠。
本发明涉及的抗体序列如下：
其中带下划线的为CDR序列，不带下划线的为FR序列，括号中的数字代表序列编号。
Tigit-5鼠单抗的VH序列：
Figure PCTCN2021131743-appb-000005
Tigit-5鼠单抗的VL序列：
Figure PCTCN2021131743-appb-000006
3Tigit-16鼠单抗的VH序列：
Figure PCTCN2021131743-appb-000007
3Tigit-16鼠单抗的VL序列：
Figure PCTCN2021131743-appb-000008
3Tigit-24鼠单抗的VH序列：
Figure PCTCN2021131743-appb-000009
3Tigit-24鼠单抗的VL序列：
Figure PCTCN2021131743-appb-000010
3Tigit-29鼠单抗的VH序列：
Figure PCTCN2021131743-appb-000011
3Tigit-29鼠单抗的VL序列：
Figure PCTCN2021131743-appb-000012
14Tigit-1-1鼠单抗的VH序列：
Figure PCTCN2021131743-appb-000013
14Tigit-1-1鼠单抗的VL序列：
Figure PCTCN2021131743-appb-000014
14Tigit-3-2鼠单抗的VH序列：
Figure PCTCN2021131743-appb-000015
14Tigit-3-2鼠单抗的VL序列：
Figure PCTCN2021131743-appb-000016
3Tigit-12鼠单抗的VH序列：
Figure PCTCN2021131743-appb-000017
3Tigit-12鼠单抗的VL序列：
Figure PCTCN2021131743-appb-000018
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。

Claims (10)

  1. 一种能够特异性识别TIGIT的抗体或其抗原结合片段，其重链CDR1、CDR2、CDR3选自SEQ ID NO:1～3、SEQ ID NO:4～6、SEQ ID NO:7～9、SEQ ID NO:10～12、SEQ ID NO:13～15、SEQ ID NO:16～18、SEQ ID NO:19～21组合中的至少一种；
    其轻链CDR1、CDR2、CDR3选自SEQ ID NO:22～24、SEQ ID NO:25～27、SEQ ID NO:28～30、SEQ ID NO:31～33、SEQ ID NO:34～36、SEQ ID NO:37～39、SEQ ID NO:40～42中的至少一种；
    可选地，所述抗体或其抗原结合片段具有选自如下CDR序列组合中的至少一种：
    Figure PCTCN2021131743-appb-100001
  2. 根据权利要求1所述的抗体或其抗原结合片段，其重链FR1、FR2、FR3、FR4选自SEQ ID NO:43～46、SEQ ID NO:47～50、SEQ ID NO:51～54、SEQ ID NO:55～58、SEQ ID NO:59～62、SEQ ID NO:63～66、SEQ ID NO:67～70组合中的至少一种；
    其轻链FR1、FR2、FR3、FR4选自SEQ ID NO:71～74、SEQ ID NO:75～78、SEQ ID NO:79～82、SEQ ID NO:83～86、SEQ ID NO:87～90、SEQ ID NO:91～94、SEQ ID NO:95～98中的至少一种；
    可选地，所述抗体或其抗原结合片段还包含选自如下骨架区序列组合中的至少一种：
    Figure PCTCN2021131743-appb-100002
    Figure PCTCN2021131743-appb-100003
  3. 根据权利要求1或2所述的抗体或其抗原结合片段，所述抗原结合片段为F(ab’) 2、Fab、scFv以及双特异抗体中的一种；
    可选地，所述抗体具有恒定区，重链恒定区序列选自IgG1、IgG2、IgG3、IgG4、IgA、IgM、IgE、IgD任意一种的恒定区序列；轻链恒定区为κ或λ链；
    可选地，所述恒定区的种属来源选自牛、马、猪、绵羊、山羊、大鼠、小鼠、狗、猫、兔、骆驼、驴、鹿、貂、鸡、鸭、鹅或人。
  4. 核酸，其编码权利要求1～3任一项所述的抗体或其抗原结合片段。
  5. 载体，其包含权利要求4所述的核酸。
  6. 细胞，其包含根据权利要求4所述的核酸或权利要求5所述的载体。
  7. 生产权利要求1～3任一项所述的抗体或其抗原结合片段的方法，包括：
    在培养基中培养权利要求6所述的细胞；以及
    从培养基中或从所培养的细胞中回收如此产生的抗体或其抗原结合片断。
  8. 药物组合物，其包括权利要求1～3任一项所述的抗体或其抗原结合片段，以及药学上可接受的赋形剂、稀释剂或载体中的一种或多种。
  9. 权利要求1～3任一项所述的抗体或其抗原结合片段在制备用于治疗或预防感染性疾病、免疫性疾病或肿瘤的药物中的应用。
  10. 试剂盒，其包含下述成分中的至少一种：
    i)权利要求1～3任一项所述的抗体或其抗原结合片段，以及任选的用于承装所述抗体或其抗原结合片段的容器；
    ii)权利要求8所述的药物组合物，以及任选的用于承装所述药物组合物的容器。
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