WO2021218879A1 - Anticorps neutralisant sars-cov-2, préparation et utilisation associées - Google Patents

Anticorps neutralisant sars-cov-2, préparation et utilisation associées Download PDF

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WO2021218879A1
WO2021218879A1 PCT/CN2021/089748 CN2021089748W WO2021218879A1 WO 2021218879 A1 WO2021218879 A1 WO 2021218879A1 CN 2021089748 W CN2021089748 W CN 2021089748W WO 2021218879 A1 WO2021218879 A1 WO 2021218879A1
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antibody
sars
cov
cov2
antigen
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PCT/CN2021/089748
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Chinese (zh)
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谢良志
孙春昀
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神州细胞工程有限公司
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
    • C07K16/08—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from viruses
    • C07K16/10—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from viruses from RNA viruses
    • C07K16/1002—Coronaviridae
    • C07K16/1003—Severe acute respiratory syndrome coronavirus 2 [SARS‐CoV‐2 or Covid-19]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies
    • A61K39/395—Antibodies; Immunoglobulins; Immune serum, e.g. antilymphocytic serum
    • A61K39/42—Antibodies; Immunoglobulins; Immune serum, e.g. antilymphocytic serum viral
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
    • A61P31/12—Antivirals
    • A61P31/14—Antivirals for RNA viruses
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N15/00—Mutation or genetic engineering; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification; Use of hosts therefor
    • C12N15/09—Recombinant DNA-technology
    • C12N15/63—Introduction of foreign genetic material using vectors; Vectors; Use of hosts therefor; Regulation of expression
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N5/00—Undifferentiated human, animal or plant cells, e.g. cell lines; Tissues; Cultivation or maintenance thereof; Culture media therefor
    • C12N5/10—Cells modified by introduction of foreign genetic material
    • C12N5/12—Fused cells, e.g. hybridomas
    • C12N5/16—Animal cells

Definitions

  • the present invention relates to the technical field of cellular immunity, and provides a humanized antibody that can block the SARS-CoV-2 spike protein (S protein) from binding to the ACE2 receptor and efficiently neutralize SARS-CoV-2 virus-infected cells. It can be used to treat infectious diseases caused by SARS-CoV-2.
  • the present invention also provides a nucleic acid sequence encoding the antibody, a vector and a cell containing the nucleic acid sequence.
  • SARS-CoV-2 The spread of SARS-CoV-2 from person to person is similar to SARS-CoV (Severe Acute Respiratory Syndrome coronavirus) and MERS-CoV (Middle East Respiratory Syndrome). It is mainly spread by respiratory droplets and can also be spread through contact.
  • the main source of infection of SARS-CoV-2 is COVID-19 patients, and those with asymptomatic infection may also become the source of infection.
  • Relevant studies have shown that the basic infection number (R0 value) of SARS-CoV-2 is between 2.24 and 3.58, suggesting that it has a strong transmission capacity [1] .
  • the population is generally susceptible to SARS-CoV-2, with an incubation period of 1-14 days, mostly 3-7 days.
  • the New Coronavirus Pneumonia Diagnosis and Treatment Plan (Trial Seventh Edition)" divides COVID-19 into mild, normal, severe, and critical.
  • the clinical symptoms of COVID-19 are mainly fever, dry cough, and fatigue.
  • a few patients are accompanied by nasal congestion, runny nose, sore throat, myalgia, and diarrhea.
  • Mild patients only manifested as low-grade fever, mild fatigue, etc., without pneumonia.
  • Critically ill patients usually have difficulty breathing and/or hypoxemia one week after the onset of onset. In severe cases, they can quickly progress to acute respiratory distress syndrome, septic shock, difficult to correct metabolic acidosis and coagulation dysfunction, and Multiple organ failure, etc. [2,3] .
  • SARS-CoV-2 and SARS-CoV share a common host cell receptor protein, angiotensin converting enzyme 2 (ACE2) [4] .
  • ACE2 angiotensin converting enzyme 2
  • S protein trimeric spike protein
  • the trimeric spike protein (S protein) of the virus binds to the ACE2 receptor and is cleaved by the host protease into the S1 polypeptide containing the receptor binding domain (RBD) and the S2 polypeptide responsible for mediating the fusion of the virus with the cell membrane. Then invade the body [5] . Therefore, finding and preparing effective antibodies to prevent the SARS-CoV-2 RBD protein from binding to the ACE2 receptor, thereby inhibiting the virus from infecting cells, has become the top priority for the prevention and treatment of SARS-CoV-2 virus infection.
  • RBD receptor binding domain
  • the humanized monoclonal antibody of the invention can effectively neutralize SARS-CoV-2 virus, and can be used as a specific antibody medicine to prevent and treat acute respiratory infections caused by SARS-CoV-2 virus.
  • the present invention provides an isolated binding antibody or antigen-binding fragment thereof that blocks the SARS-CoV-2 spike protein and ACE2 receptor, which comprises
  • the heavy chain variable region whose heavy chain CDR1, heavy chain CDR2 and heavy chain CDR3 domains respectively comprise SEQ ID NOs: 13, 14 and 15, and/or
  • the light chain variable region, the light chain CDR1, light chain CDR2 and light chain CDR3 domains respectively comprise SEQ ID NOs: 10, 11 and 12
  • the antibody or antigen-binding fragment thereof comprises:
  • Heavy chain variable region whose sequence includes SEQ ID NO: 22 or has at least 85%, 88%, 90%, 95%, 98%, or 99% sequence identity with it;
  • the light chain variable region the sequence of which comprises SEQ ID NO: 23 or has at least 85%, 88%, 90%, 95%, 98%, or 99% sequence identity with it.
  • the antibody or antigen-binding fragment thereof is a humanized antibody, chimeric or murine antibody.
  • the antibody or antigen-binding fragment thereof has an antibody constant region of IgG, IgM, IgA subtype, preferably, IgG1, IgG2, or IgG4 subtype antibody; more preferably, because of its Fc region IgG1, IgG2 or IgG4 subtype antibodies with altered amino acid sequence and/or glycosylation form of Fc receptor and/or C1q complement binding function.
  • the antibody or antigen-binding fragment thereof in one embodiment, the antibody or antigen-binding fragment thereof,
  • the average K D of its binding affinity to SARS-CoV-2 RBD is 11.7E-11 to 1.3E-11M, preferably 5.9E-11 to 2.6E-11M, more preferably 3.9E-11M; and/or
  • the average K D of its binding affinity to SARS-CoV S1 is 11.1E-10 to 1.2E-10M, preferably 5.6E-10 to 2.5E-10M, more preferably 3.7E-10M.
  • the epitope of the antibody or antigen-binding fragment thereof is N439 and T500 of the SARS-CoV-2 virus spike protein.
  • the antibody or antigen-binding fragment thereof further comprises:
  • the heavy chain constant region preferably, its sequence comprises SEQ ID NO: 24 or has at least 90%, 92%, 95%, 98% or 99% sequence identity with it; and/or
  • the light chain constant region preferably, its sequence comprises SEQ ID NO: 25 or has at least 90%, 92%, 95%, 98% or 99% sequence identity with it.
  • the average in vivo exposure C max and AUC last are 108.96 ⁇ g/mL and 9922.11 h ⁇ g/mL, respectively, and the average half-life is t 1/2 It was 286.16h, and the clearance rate Cl was 0.30mL/h/kg.
  • the antibody is expressed by HEK-293 knocked out of fut8 gene.
  • the antibody further comprises:
  • the heavy chain constant region preferably, its sequence comprises SEQ ID NO: 45 or has at least 90%, 92%, 95%, 98% or 99% sequence identity with it; and/or
  • the light chain constant region preferably, its sequence comprises SEQ ID NO: 25 or has at least 90%, 92%, 95%, 98% or 99% sequence identity with it.
  • CD32a and CD32b There is almost no combination with CD32a and CD32b;
  • the average in vivo exposure C max and AUC last are 115.04 ⁇ g/mL and 11159.82 h ⁇ g/mL, respectively, and the average half-life is t 1/2 It is 320.00h, and the clearance rate Cl is 0.23mL/h/kg.
  • the antibody is expressed by HEK-293 knocked out of fut8 gene.
  • the binding ability to CD16a is stronger than that of CoV2-HB27 antibody of IgG1 subtype
  • the antibody further comprises
  • the heavy chain constant region preferably, its sequence comprises SEQ ID NO: 49 or has at least 90%, 92%, 95%, 98% or 99% sequence identity with it; and/or
  • the light chain constant region preferably, its sequence comprises SEQ ID NO: 25 or has at least 90%, 92%, 95%, 98% or 99% sequence identity with it.
  • the antibody is expressed by HEK-293 knocked out of fut8 gene.
  • the binding ability to CD16a is stronger than that of CoV2-HB27 antibody of IgG1 subtype
  • the binding capacity to CD64 is stronger than that of CoV2-HB27 antibody of IgG1 subtype
  • CoV2-HB27 antibody that mediates ADCC stronger than IgG1 subtype
  • the antibody or antigen-binding fragment thereof is a monoclonal antibody.
  • the antigen-binding fragment is Fv, Fab, Fab', Fab'-SH, F(ab')2, Fd fragment, Fd' fragment, single-chain antibody molecule or single-domain antibody;
  • the antibody molecule is preferably scFv, di-scFv, tri-scFv, diabody or scFab.
  • the present invention provides a modified antibody-drug molecule, which comprises the antibody of the present invention or its antigen-binding fragment and small molecules or biological macromolecules covalently or non-covalently linked thereto, preferably via a linker connect.
  • the present invention provides a nucleic acid, which encodes the antibody or antigen-binding fragment thereof according to the present invention, which is mRNA and/or DNA.
  • the nucleic acid comprises
  • the present invention provides an expression vector comprising the nucleic acid according to the present invention.
  • the present invention provides a host cell comprising the nucleic acid according to the present invention or the expression vector according to the present invention.
  • the present invention provides a method for producing the antibody or antigen-binding fragment thereof according to the present invention, which comprises culturing the host cell according to the present invention under conditions suitable for antibody expression, and from The expressed antibody is recovered from the culture medium.
  • the present invention provides a pharmaceutical composition
  • a pharmaceutical composition comprising
  • a pharmaceutically acceptable carrier optionally
  • One or more other therapeutic agents are selected from antiviral drugs or inflammatory factor inhibitors, small molecule chemical drugs of other mechanisms; preferably, the antiviral drugs are selected from including but not limited to type I interferon Drugs, antibodies, protease inhibitors, RNA-dependent RNA polymerase (RdRP) inhibitors, and host-targeted antiviral drugs.
  • antiviral drugs are selected from including but not limited to type I interferon Drugs, antibodies, protease inhibitors, RNA-dependent RNA polymerase (RdRP) inhibitors, and host-targeted antiviral drugs.
  • the antibody or antigen-binding fragment thereof according to the present invention is used to prevent and treat diseases caused by SARS-CoV-2 infection.
  • the antibody or antigen-binding fragment thereof according to the present invention is used to prepare a medicine for preventing and treating diseases caused by SARS-CoV-2 infection.
  • the present invention provides a pharmaceutical combination comprising
  • the antibody or antigen-binding fragment thereof according to the present invention the modified antibody-drug molecule according to the present invention, the nucleic acid according to the present invention, the expression vector according to the present invention, the drug according to the present invention Composition; and one or more additional therapeutic agents.
  • the present invention provides a kit comprising
  • the antibody or antigen-binding fragment thereof according to the present invention, the modified antibody-drug molecule according to the present invention, the nucleic acid according to the present invention, the expression vector according to the present invention, the drug according to the present invention The composition; preferably, it further comprises a device for administration.
  • the present invention provides a method for preventing and treating diseases caused by SARS-CoV-2 infection, which comprises administering to a subject the antibody or antigen-binding fragment thereof according to the present invention, as described in the present invention.
  • the present invention provides an isolated binding antibody or antigen-binding fragment thereof that blocks the SARS-CoV-2 spike protein and ACE2 receptor, and its binding epitope is N439 of the SARS-CoV-2 spike protein And T500.
  • the present invention provides a SARS-CoV-2 spike protein binding epitope, which is N439 and T500 of SARS-CoV-2 spike protein.
  • Figure 1 Screening of monoclonal phage binding to SARS-CoV-2 protein.
  • Figure 2 The binding ability of murine antibodies with SARS-CoV-2 S1 and ECD proteins.
  • Figure 3 Flow cytometric detection of the binding of mouse antibodies to SARS-CoV-2 S1 protein.
  • FIG. 4 Murine antibody competes for the binding of ACE2 to SARS-CoV-2 RBD and S1 protein.
  • FIG. 5 Murine antibody neutralizes SARS-CoV-2 pseudovirus.
  • Figure 6 The binding ability of humanized antibodies with SARS-CoV-2 RBD, S1 and ECD proteins.
  • Figure 7 Humanized antibodies compete for the binding of ACE2 protein to SARS-CoV-2 S1 protein.
  • Figure 8 The affinity detection of humanized antibody with SARS-CoV-2 RBD protein and S1 protein.
  • Figure 9 Humanized antibody neutralizes SARS-CoV-2 pseudovirus.
  • FIG. 10 Epitope diagram of CoV2-mhB27 epitope analysis (A) and ELISA test results (B). SARS-CoV-2RBD in A is represented by a white surface model, all designed mutation sites are represented by light gray, and the identified highly significant epitope of mhB27 is represented by black.
  • FIG. 11 Binding of CoV2-HB27 antibodies with different Fc functional forms to CD16a.
  • Figure 12 Binding of CoV2-HB27 antibodies to CD32 in different Fc functional forms.
  • Figure 13 Binding of CoV2-HB27 antibodies with different Fc functional forms to CD64.
  • FIG. 14 Binding of CoV2-HB27 antibodies with different Fc functional forms to C1q.
  • Figure 15 Different Fc functional forms of CoV2-HB27 antibody on ADCC mediated by target cells expressing SARS-CoV-2 S protein.
  • FIG. 16 ADCP mediated by different Fc functional forms of CoV2-HB27 antibodies on target cells expressing SARS-CoV-2 S protein.
  • Figure 17 CDC mediated by different Fc functional forms of CoV2-HB27 antibodies on target cells expressing SARS-CoV-2 S protein.
  • antibody means an immunoglobulin molecule, and refers to any form of antibody that exhibits the desired biological activity. Including but not limited to monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies and multispecific antibodies (such as bispecific antibodies), and even antibody fragments.
  • the full-length antibody structure preferably comprises 4 polypeptide chains, usually 2 heavy (H) chains and 2 light (L) chains connected to each other by disulfide bonds. Each heavy chain contains a heavy chain variable region and a heavy chain constant region. Each light chain contains a light chain variable region and a light chain constant region. In addition to this typical full-length antibody structure, its structure also includes other derivative forms.
  • variable region refers to the domain in the heavy or light chain of an antibody that is involved in the binding of the antibody to the antigen.
  • the variable regions of the heavy and light chains of natural antibodies (VH and VL, respectively) generally have similar structures and can be further subdivided into hypervariable regions interspersed in more conservative regions (called framework regions (FR)) (Called the complementarity determining region (CDR)).
  • CDR complementarity determining region
  • CDR1, CDR2, and CDR3 refers to the amino acid residues of the variable region of an antibody, the presence of which is necessary for antigen binding.
  • Each variable region usually has 3 CDR regions identified as CDR1, CDR2, and CDR3.
  • Each complementarity determining region may contain amino acid residues from the “complementarity determining region” defined by Kabat (Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD). .1991)) and/or those residues from the "hypervariable loop" (Chothia and Lesk; J Mol Biol 196:901-917 (1987)).
  • framework or "FR” residues are those variable region residues other than the CDR residues as defined herein.
  • Each heavy chain variable region and light chain variable region usually contains 3 CDRs and up to 4 FRs, and the CDRs and FRs are arranged in the following order, for example, from the amino terminal to the carboxy terminal: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4.
  • CDR complementarity determining region
  • FR framework region
  • constant region refers to such amino acid sequences on the light chain and heavy chain of an antibody that do not directly participate in the binding of the antibody to the antigen, but exhibit a variety of effector functions, such as antibody-dependent cytotoxicity.
  • complete antibodies can be classified into five classes of antibodies: IgA, IgD, IgE, IgG, and IgM, among which IgG and IgA can be further divided into subclasses (isotypes), such as IgG1, IgG2 , IgG3, IgG4, IgA1 and IgA2.
  • the heavy chains of the five types of antibodies are classified into ⁇ , ⁇ , ⁇ , ⁇ , and ⁇ chains, respectively.
  • the amino acid sequence of the constant region of its light chain the light chain of an antibody can be classified into ⁇ and ⁇ . .
  • an "antigen-binding fragment of an antibody” comprises a part of a complete antibody molecule that retains at least some of the binding specificity of the parent antibody, and usually includes at least part of the antigen-binding region or variable region (for example, one or more CDRs) of the parent antibody.
  • antigen-binding fragments include, but are not limited to, Fv, Fab, Fab', Fab'-SH, F(ab')2, Fd fragment, Fd' fragment, single-chain antibody molecules (e.g., scFv, di-scFv, or tri-scFv , Diabody or scFab), single domain antibody.
  • antibody fragment is a non-complete antibody molecule that retains at least some biological properties of the parent antibody, and examples thereof include, but are not limited to, Fc fragments in addition to those described in the above-mentioned "antigen-binding fragments".
  • modified drug molecule refers to an antibody or fragment thereof, such as an antigen-binding fragment that forms a covalent or non-covalent link with another molecule or forms a recombinant multi-target fusion drug, and the other molecule is selected from a small molecule compound or a biological Macromolecule.
  • chimeric antibody refers to an antibody in which a part of the heavy chain and/or light chain is derived from a specific source or species, and the remaining part is derived from a different source or species.
  • Humanized antibodies are a subset of “chimeric antibodies.”
  • humanized antibody or “humanized antigen-binding fragment” is defined herein as an antibody or antibody fragment: (i) derived from a non-human source (for example, a transgenic mouse carrying a heterologous immune system) And antibodies based on human germline sequences; or (ii) chimeric antibodies in which the variable region is of non-human origin and the constant region is of human origin; or (iii) CDR-grafted, in which the CDR of the variable region is derived from a non-human source, and One or more framework regions of the variable region are of human origin, and the constant region (if any) is of human origin.
  • the purpose of "humanization” is to eliminate the immunogenicity of non-human source antibodies in the human body, while retaining the greatest possible affinity.
  • a “monoclonal antibody” refers to an antibody obtained from a substantially homogeneous antibody population, that is, the population comprising a single antibody is identical except for possible mutations (such as natural mutations) that may be present in very small amounts. Therefore, the term “monoclonal” indicates the nature of the antibody, that is, it is not a mixture of unrelated antibodies. In contrast to polyclonal antibody preparations, which usually include different antibodies directed against different determinants (epitopes), each monoclonal antibody of a monoclonal antibody preparation is directed against a single set of determinants on the antigen. In addition to their specificity, the advantage of monoclonal antibody preparations is that they are generally not contaminated by other antibodies. The term “monoclonal” should not be understood as requiring the production of the antibody by any specific method. The term monoclonal antibody specifically includes chimeric antibodies, humanized antibodies and human antibodies.
  • the antibody "specifically binds" to an antigen of interest, such as a virus-associated antigen protein (herein, spike protein S), that is, binds to the antigen with sufficient affinity so that the antibody can be used as a therapeutic agent, and targets those expressing the antigen.
  • an antigen of interest such as a virus-associated antigen protein (herein, spike protein S)
  • spike protein S virus-associated antigen protein
  • Viruses or cells and have no significant cross-reactivity with other proteins or with proteins other than homologs and variants (such as mutant forms, splice variants, or proteolytically truncated forms) of the antigen target mentioned above No significant cross-reaction.
  • binding affinity refers to the strength of the sum of non-covalent interactions between a single binding site of a molecule and its binding partner. Unless otherwise specified, "binding affinity” as used herein refers to intrinsic binding affinity, which reflects a 1:1 interaction between members of a binding pair (eg, antibody and antigen). "KD”, "association rate constant kon” and “dissociation rate constant koff” are generally used to describe the affinity between a molecule (such as an antibody) and its binding partner (such as an antigen), that is, how tightly a ligand binds to a specific protein. Binding affinity is affected by interactions between non-covalent molecules, such as hydrogen bonds, electrostatic interactions, hydrophobicity between two molecules and van der Waals forces. In addition, the binding affinity between the ligand and its target molecule may be affected by the presence of other molecules. Affinity can be analyzed by conventional methods known in the art, including the ELISA described herein.
  • epitope includes any protein determinant capable of specifically binding to an antibody or T cell receptor.
  • Epitope determinants usually consist of chemically active surface groups of molecules (such as amino acids or sugar side chains, or combinations thereof), and usually have specific three-dimensional structural characteristics and specific charge characteristics.
  • Isolated antibodies are antibodies that have been identified and isolated from cells that naturally express the antibody. Isolated antibodies include in situ antibodies in recombinant cells as well as antibodies that are usually prepared through at least one purification step.
  • sequence identity between two polypeptide or nucleic acid sequences means the percentage of the number of residues that are identical between the sequences to the total number of residues.
  • sequences being compared are aligned in a way that produces the largest match between the sequences, and the gaps in the alignment (if any) are resolved by a specific algorithm.
  • Preferred computer program methods for determining the identity between two sequences include, but are not limited to, the GCG program package, including GAP, BLASTP, BLASTN and FASTA (Altschul et al., 1990, J. Mol. Biol. 215: 403-410) .
  • the above procedures are publicly available from the International Center for Biotechnology Information (NCBI) and other sources.
  • NCBI International Center for Biotechnology Information
  • Smith Waterman algorithm can also be used to determine identity.
  • receptor is a biochemical concept that refers to a class of molecules that can transmit extracellular signals and produce specific effects in cells. The effect may only last for a short period of time, such as changing cell metabolism or cell movement. It may also be a long-term effect, such as up-regulating or down-regulating the expression of a certain gene or genes.
  • Fc receptor refers to a receptor that binds to the Fc region of an antibody. Natural sequence human FcR is preferred, and receptors ( ⁇ receptors) that bind to IgG antibodies are preferred, which include Fc ⁇ RI, Fc ⁇ RII and Fc ⁇ RIII subtypes, and variants of these receptors. Other FcRs are included in the term “FcR”.
  • the term also includes the neonatal receptor (FcRn), which is responsible for the transport of maternal IgG to the fetus (Guyer et al., Journal of Immunology 117:587 (1976) and Kim et al., Journal of Immunology 24:249 (1994)).
  • FcRn neonatal Fc receptor
  • the neonatal Fc receptor (FcRn) plays an important role in the metabolic fate of IgG antibodies in the body. FcRn functions to rescue IgG from the lysosomal degradation pathway, thereby reducing its clearance in serum and increasing its half-life. Therefore, the in vitro FcRn binding properties/characteristics of IgG indicate its in vivo pharmacokinetic properties in the blood circulation.
  • effector function refers to those biological activities attributable to the Fc region of an antibody, which vary with antibody isotype.
  • antibody effector functions include: C1q binding and complement-dependent cytotoxicity (CDC), Fc receptor binding, "antibody-dependent cell-mediated cytotoxicity” (ADCC), antibody-dependent cellular phagocytosis (ADCP), Cytokine secretion, immune complex-mediated antigen uptake by antigen-presenting cells, down-regulation of cell surface receptors (such as B cell receptors), and B cell activation.
  • effector cells refers to leukocytes that express one or more FcRs and perform effector functions.
  • the effector cell at least expresses FcyRIII and performs ADCC effector function.
  • human leukocytes that mediate ADCC include peripheral blood mononuclear cells (PBMC), natural killer (NK) cells, monocytes, cytotoxic T cells, and neutrophils.
  • PBMC peripheral blood mononuclear cells
  • NK natural killer cells
  • monocytes cytotoxic T cells
  • neutrophils effector cells can be isolated from natural sources, for example, blood. Effector cells are usually lymphocytes associated with the effector stage and function to produce cytokines (helper T cells), kill cells infected by pathogens (cytotoxic T cells) or secrete antibodies (differentiated B cells) .
  • Immune cells include cells that have hematopoietic origin and play a role in immune responses. Immune cells include: lymphocytes, such as B cells and T cells; natural killer cells; myeloid cells, such as monocytes, macrophages, eosinophils, mast cells, basophils, and granulocytes.
  • ADCC antibody-dependent cell-mediated cytotoxicity
  • cytotoxic cells such as NK cells, neutrophils, and macrophages.
  • Ig on the Fc ⁇ receptor enables these cytotoxic effector cells to specifically bind to the target cell carrying the antigen, and then kill the target cell using, for example, a cytotoxin.
  • an in vitro ADCC assay can be performed, such as the in vitro ADCC assay described in U.S. Patent No. 5,500,362 or 5,821,337 or U.S. Patent No. 6,737,056 (Presta), and the method described in the Examples of this application .
  • Useful effector cells for such assays include PBMC and NK cells.
  • “Complement dependent cytotoxicity” or “CDC” refers to the lysis of target cells in the presence of complement.
  • the activation of the classical complement pathway is initiated by the binding of the first component of the complement system (C1q) to an antibody (of the appropriate subclass), wherein the antibody binds to its corresponding antigen.
  • C1q the first component of the complement system
  • CDC assays can be performed, such as the CDC assays described in Gazzano-Santoro et al., J. Immunol Methods 202:163 (1996), such as the methods described in the examples of this application, such as The method described in U.S. Patent No. 6,194,551B1 and WO1999/51642, in which polypeptide variants with altered Fc region amino acid sequence (polypeptides with variant Fc region) and polypeptide variants with enhanced or reduced C1q binding are described .
  • ADCP antibody-dependent cellular phagocytosis
  • amino acid sequence and nucleotide sequence of the antibody of the present invention as well as Fc functional modification.
  • the present invention first uses recombinant SARS-CoV RBD protein to immunize mice, and then obtains a scFv antibody clone that binds to SARS-CoV-2 RBD protein through screening of the phage antibody library. After that, the nucleotide sequences encoding the heavy chain and light chain variable regions of the scFv antibody were spliced with the nucleotide sequences encoding the mouse IgG1 heavy chain constant region and the mouse kappa light chain constant region, respectively, and inserted into the transient Transform the expression vector for culture expression. The protein A purification column was used for purification to obtain high-purity mouse antibodies.
  • the classical CDR transplantation method is used to humanize the mouse antibody [8,9] .
  • the similarity with the murine light chain and heavy chain variable regions is more than 50%
  • the framework regions of the light chain and heavy chain variable regions are similar to the amino acid sequences of the framework regions of the light chain and heavy chain variable regions of the antibody to be modified
  • An antibody with a sex ratio of more than 50% is used as a humanized template, and the three CDR sequences of the light chain or heavy chain of the mouse antibody are replaced in the corresponding CDR amino acid sequence in the humanized template.
  • human-source templates for light and heavy chain variable region transplantation were selected.
  • the 3 CDR sequences of the light chain and the heavy chain of the murine antibody were transplanted into the corresponding human template. Since the key points of the mouse-derived framework region are essential to support the activity of the CDR, the key points were backmutated to the sequence of the murine antibody.
  • the light chain/heavy chain signal peptide sequence, the back-mutated humanized antibody light chain/heavy chain variable region sequence, and the human IgG4 heavy chain constant region/human kappa light chain constant region sequence were spliced in sequence to obtain the humanization
  • the amino acid sequence and nucleotide sequence of the antibody CoV2-HB27.
  • the present invention further modified the Fc function of CoV2-HB27.
  • They are: 1) genetically engineered heavy chain IgG1 constant region to obtain a humanized antibody CoV2-HB27-Fd6-IgG1 with reduced Fc function IgG1 subtype; 2) Defucoid expressed in mammalian cells knocked out with Fut8 gene Glycosylated IgG1 subtype CoV2-HB27-Ae0-IgG1 antibody; and 3) genetically engineered heavy chain IgG1 constant region to obtain an enhanced Fc function IgG1 subtype humanized antibody CoV2-HB27-Fe4-IgG1.
  • the invention also relates to nucleic acid molecules encoding the antibodies of the invention or parts thereof. Some example sequences of these nucleic acid molecules are shown in the sequence listing.
  • the nucleic acid molecule of the present invention is not limited to the sequence disclosed herein, but also includes variants and other nucleic acid forms corresponding thereto, such as mRNA, cDNA and variants thereof.
  • the variants of the present invention can be described with reference to their physical characteristics in hybridization. Those skilled in the art will recognize that using nucleic acid hybridization techniques, nucleic acids can be used to identify their complements and their equivalents or homologs. It will also be recognized that hybridization can occur with less than 100% complementarity. However, considering the appropriate selection of conditions, hybridization techniques can be used to distinguish DNA sequences based on their structural correlation with specific probes.
  • the invention also provides a recombinant construct comprising one or more nucleotide sequences of the invention.
  • the recombinant construct of the present invention can be used with a vector, such as a plasmid, phagemid, phage or viral vector, into which the nucleic acid molecule encoding the antibody of the present invention is inserted.
  • the antibodies provided herein can be prepared by recombinantly expressing nucleotide sequences encoding light and heavy chains or parts thereof in a host cell.
  • one or more recombinant expression vectors carrying the nucleotide sequence encoding the light chain and/or the heavy chain or part thereof can be used to transfect the host cell so that the light chain and the heavy chain are in the Expressed in host cells.
  • Standard recombinant DNA methodology is used to prepare and/or obtain nucleic acids encoding heavy and light chains, incorporate these nucleic acids into recombinant expression vectors and introduce the vectors into host cells, such as Sambrook, Fritsch and Maniatis (eds.
  • the nucleotide sequence encoding the variable region of the heavy chain and/or light chain can be converted into, for example, a nucleotide sequence encoding a full-length antibody chain, Fab fragment or scFv: for example, the variable region encoding the light chain can be
  • the DNA fragment of the region or heavy chain variable region is operably linked (so that the amino acid sequences encoded by the two DNA fragments are in frame) to another DNA fragment encoding, for example, an antibody constant region or a flexible linker.
  • the sequences of human heavy and light chain constant regions are known in the art (see, for example, Kabat, EA, el. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, USDepartment of Health and Human Services, NIH Publication No. 91-3242), DNA fragments including these regions can be obtained by standard PCR amplification.
  • the nucleotide sequence encoding the desired antibody can be inserted into an expression vector, and then the expression vector can be transfected into a suitable host cell.
  • suitable host cells are prokaryotic cells and eukaryotic cells. Examples of prokaryotic host cells are bacteria, and examples of eukaryotic host cells are yeast, insect or mammalian cells. It should be understood that the design of the expression vector including the selection regulatory sequence is affected by many factors, such as the choice of host cell, the expression level of the desired protein, and whether the expression is constitutive or inducible.
  • the antibody of the present invention can be recovered and purified from recombinant cell culture by known methods, including but not limited to, ammonium sulfate or ethanol precipitation, acid extraction, protein A affinity chromatography, protein G affinity chromatography, anion Or cation exchange chromatography, phosphocellulose chromatography, hydrophobic interaction chromatography, affinity chromatography, hydroxyapatite chromatography, and lectin chromatography.
  • High performance liquid chromatography (“HPLC”) can also be used for purification. See, for example, Colligan, Current Protocols in Immunology, or Current Protocols in Protein Science, John Wiley & Sons, NY, NY, (1997-2001), such as Chapters 1, 4, 6, 8, 9, and 10, each by reference The full text is included in this article.
  • the antibodies of the present invention include natural purified products, products of chemical synthesis methods, and products produced by recombinant technology from prokaryotic and eukaryotic hosts.
  • the eukaryotic hosts include, for example, yeast, higher plants, insects and mammalian cells.
  • the antibodies of the invention can be glycosylated or non-glycosylated. Such methods are described in many standard laboratory manuals, such as Sambrook above, sections 17.37-17.42; Ausubel above, chapters 10, 12, 13, 16, 18 and 20.
  • an embodiment of the present invention is also a host cell comprising the vector or nucleic acid molecule, wherein the host cell may be a higher eukaryotic host cell such as mammalian and insect cells, a lower eukaryotic host cell such as yeast cell, and It may be a prokaryotic cell such as a bacterial cell.
  • the host cell may be a higher eukaryotic host cell such as mammalian and insect cells, a lower eukaryotic host cell such as yeast cell, and It may be a prokaryotic cell such as a bacterial cell.
  • the ELISA test showed that the obtained mouse antibody CoV2-mhB27 has a good binding with the transiently expressing SARS-CoV-2 S1 protein HF-nCoV-SPIKE-8D3 cells, and its binding EC 50 is 2.77 ⁇ g/mL; it can effectively compete with ACE2
  • the binding of the protein to RBD and S1 protein has a competitive EC 50 of 44.0ng/mL and 24.0ng/mL, respectively; it can effectively neutralize the SARS-CoV-2 pseudovirus in a concentration-dependent manner, with a neutralization IC 50 of 8.7ng /mL.
  • the humanized antibody CoV2-HB27 has good binding with SARS-CoV-2 RBD, S1 and ECD proteins.
  • the binding exhibits an "S" curve growth, and the binding EC 50 is 22.2ng/mL, 183.3ng/mL and respectively. 972.4ng / mL; can be effectively suppressed with the S1 binding protein 2 SARS-CoV-ACE2 protein, inhibition EC 50 of 178.6ng / mL.
  • CoV2-HB27 has high affinity with SARS-CoV-2 RBD and S1 protein.
  • CoV2-HB27 can effectively neutralize SARS-CoV2 pseudovirus, and concentration-dependent manner, and the IC 50 of 5.9ng / mL.
  • the defucosylated Ae0-IgG1 form antibody and the Fc-enhanced Fe4-IgG1 form antibody have similar binding capacity to CD16a, and are stronger than the IgG1 subtype CoV2-HB27 antibody ;
  • the Fd6-IgG1 form of antibody that reduces Fc function only weakly binds to CD16a.
  • the Fe4-IgG1 form antibody with enhanced Fc function has the strongest binding ability to CD32a and CD32b, which is better than the defucosylated Ae0-IgG1 form antibody and IgG1 subtype CoV2 -HB27 antibody; Fd6-IgG1 form antibody which reduces Fc function has almost no binding to CD32a and CD32b.
  • the Fe4-IgG1 form antibody with enhanced Fc function has the strongest binding ability to CD64, which is better than the defucosylated Ae0-IgG1 form antibody and the IgG1 subtype CoV2-HB27 Antibody; Fd6-IgG1 form of antibody that reduces Fc function only weakly binds to CD64.
  • the Fe4-IgG1 form antibody with enhanced Fc function has the strongest binding ability to C1q, which is better than the defucosylated Ae0-IgG1 form antibody and IgG1 subtype CoV2-HB27 Antibody; Fd6-IgG1 form of antibody that reduces Fc function only weakly binds to C1q.
  • CoV2-HB27 antibodies have no CDC effect on target cells expressing SARS-CoV-2S protein.
  • the antibody of the present invention can be used to treat, prevent or detect diseases caused by SARS-CoV-2 virus, such as acute respiratory infectious diseases caused by SARS-CoV-2 virus.
  • One or more of the antibody, antigen-binding fragment, modified antibody-drug molecule, nucleic acid, carrier and at least one other chemical agent of the present invention can be prepared into a pharmaceutical composition, which includes the above-mentioned active ingredients and one or more A pharmaceutically acceptable carrier, diluent or excipient; optionally, one or more other therapeutic agents may also be included.
  • the invention also relates to a pharmaceutical package and a kit comprising one or more containers containing the above-mentioned pharmaceutical composition of the invention.
  • a pharmaceutical package and a kit comprising one or more containers containing the above-mentioned pharmaceutical composition of the invention.
  • Related to this type of container may be a reminder in the form prescribed by a government agency that regulates the production, use, or sale of drugs or biological products, which reflects that the product is approved for human administration by the agency that produces, uses, or sells the product.
  • the pharmaceutical composition of the present invention can be prepared in a manner known in the art, for example, by conventional mixing, dissolving, granulating, grinding, emulsifying, wrapping, embedding or freeze-drying methods.
  • the pharmaceutical composition containing the compound of the present invention formulated in an acceptable carrier After the pharmaceutical composition containing the compound of the present invention formulated in an acceptable carrier has been prepared, they can be placed in a suitable container and labeled for the treatment of the indicated condition.
  • suitable container and labeled for the treatment of the indicated condition.
  • labels would include the amount, frequency, and method of administration.
  • composition comprising the antibody of the present invention is also combined with one or more other therapeutic agents, wherein the resulting combination does not cause unacceptable adverse effects.
  • Example 1 Screening of murine antibodies that bind to SARS-CoV-2 RBD using phage antibody display library
  • the recombinant SARS-CoV-2-RBD-mFc protein (source: Beijing Yiqiao Shenzhou Technology Co., Ltd., Cat.40592-V05H, SEQ ID NO:1, the same below) was used to immunize mice.
  • the specific method is: mixing recombinant SARS-CoV-2-RBD-mFc protein with Freund's adjuvant, using the mixture for secondary immunization, each immunization dose is 50 ⁇ g, subcutaneous injection, and the immunization interval is 2 weeks. Seven days after the second immunization, blood was collected from the intracanthal venous plexus of the orbit.
  • Coated recombinant SARS-CoV-2-RBD-his protein (source: Beijing Yiqiao Shenzhou Technology Co., Ltd., Cat.40592-V08B), and ELISA method was used to detect the serum titer of mice after immunization.
  • the titer of the second immune serum was diluted 16000 times to reach 2.228. After 10 days, the mice were sacrificed, and the spleen tissues of the mice were frozen and stored in liquid nitrogen.
  • TriPure Isolation Reagent kit (source: Roche, Cat. No. 11 667 165 001) to extract RNA from mouse spleen tissue, and use reverse transcription kit TriPure Isolation Reagent (source: Invitrogen Cat. No. 18080-051) CDNA is obtained after reverse transcription.
  • the overlap extension splicing PCR method was used to splice the nucleotide sequence encoding the mouse antibody light chain and heavy chain variable region sequence into a scFv encoding Nucleotide sequence, light and heavy chain variable regions through linker:
  • the solid phase screening method was used to screen the phages that bind to the SARS-CoV-2 RBD protein.
  • SARS-CoV-2-RBD-mFc protein at a concentration of 10 ⁇ g/mL was coated on a 96-well plate with 100 ⁇ L per well and coated overnight at 4°C. The plate was washed the next day and blocked for 1 hour at room temperature, then added to the phage library and incubated at 37°C for 2 hours.
  • Monoclonal phages were selected from the enriched library for expression, and their binding to SARS-CoV-2 S and RBD proteins was detected by ELISA.
  • the SARS-CoV-2-S1-his protein (source: Beijing Yiqiao Shenzhou Technology Co., Ltd., the same below)
  • the SARS-CoV-2-RBD-mFc protein and the negative control CD155(D1)- mFc (source: Shenzhou Cell Engineering Co., Ltd.) proteins were coated on 96-well plates, 100 ⁇ L per well, and coated overnight at 4°C. The plate was washed the next day and blocked at room temperature for 2 hours.
  • the plate was washed to remove unbound proteins, and then a 10-fold diluted phage monoclonal was added to incubate. The plate was washed to remove unbound phage, and M13/HRP was added to incubate and the plate was washed repeatedly. Add the substrate color solution for color development, and read the OD 450 by the microplate reader after termination. Take the detected protein as the abscissa and OD 450 as the ordinate, analyze and graph with GraphPad Prism software.
  • the nucleotide sequence of the heavy chain variable region of the CoV2-mB27scFv antibody was amplified by PCR, and inserted into the heavy chain signal peptide (SEQ ID NO: 40) and human IgG1 constant region (SEQ ID NO: 6) by the In-fusion method.
  • the expression vector of the human-mouse chimeric antibody CoV2-mhB27 heavy chain was obtained from the pSE vector (source: Shenzhou Cell Engineering Co., Ltd., the same below) digested with ScaI+Nhe I (source: Fermentas).
  • the nucleotide sequence of the light chain variable region of CoV2-mB27scFv was amplified by PCR and inserted into the light chain signal peptide (SEQ ID NO: 41) and human kappa constant region (SEQ ID NO: 7) by the In-fusion method.
  • the expression vector of human-mouse chimeric CoV2-mhB27 light chain (SEQ ID NO: 37) was obtained from pSE vector digested with ScaI+BsiWI (source: Fermentas, the same below).
  • Amplification variable region primers :
  • the culture solution was centrifuged at 4000 rpm for 25 min, the supernatant was collected, and 1/5 of the supernatant volume was added to stock buffer (source: Shenzhou Cell Engineering Co., Ltd.). Equilibrate the protein A chromatography column (source: Shenzhou Cell Engineering Co., Ltd., the same below) with PBS for 5-10 times the column volume, add the filtered culture supernatant to the chromatography column, and equilibrate again for 5-10 times the column volume, The sample was eluted with sodium acetate buffer (source: Shenzhou Cell Engineering Co., Ltd.). After the sample is eluted, it is neutralized to neutral with Tris buffer for later use.
  • stock buffer source: Shenzhou Cell Engineering Co., Ltd.
  • SARS-CoV-2 S1 protein 1000ng/mL, 333.3ng/mL, 111.1ng/mL, 37.0ng/mL, 12.4ng/mL, 4.12ng/mL and 1.37ng/mL
  • SARS-CoV -2ECD protein 9000ng/mL, 3000ng/mL, 1000ng/mL, 333.3ng/mL, 111.1ng/mL, 37.0ng/mL, 12.4ng/mL and 4.12ng/mL, source: Beijing Yiqiao Shenzhou Technology Co., Ltd. , The same below
  • the plate was washed the next day and blocked at room temperature for 1 hour, then 100 ⁇ L of 1 ⁇ g/mL murine antibody CoV2-mhB27 was added and incubated for 1 hour, then the plate was washed to remove unbound antibody, and 0.25 ⁇ g/mL Goat anti-human IgG Fc/HRP (source: KPL) was added. Company, the same below) Wash the plate repeatedly after incubation, add substrate color developing solution for color development, and detect OD 450 after termination.
  • CoV2-mhB27 antibody to SARS-CoV2 S1 binding protein and ECD protein showed an "S" curve growth, which binds EC 50 respectively 116.4ng / mL and 306.6ng / mL.
  • This example further verified the binding ability of the murine antibody with the transiently expressing SARS-CoV-2 S1 protein HF-nCoV-SPIKE-8D3 cell by flow cytometry. Take HF-nCoV-SPIKE-8D3 cells (source: Shenzhou Cell Engineering Co., Ltd.) in the logarithmic growth phase and place them in a flow tube, 5 ⁇ 10 5 cells/tube.
  • mice antibody CoV2-mhB27 33.3 ⁇ g/mL, 16.7 ⁇ g/mL, 8.3 ⁇ g/mL, 4.2 ⁇ g/mL, 2.1 ⁇ g/mL, 1.04 ⁇ g/mL and 0.52 ⁇ g/mL
  • H7N9 -R1 is a negative control antibody
  • the PBS washing solution was used to wash, and the unbound antibody was removed by centrifugation.
  • FITC-labeled Goat anti-Human IgG Fc secondary antibody source: KPL company
  • the cells were resuspended in 200 ⁇ L PBS, filtered with 400 meshes, and tested on a flow cytometer.
  • the results shown in Figure 3 CoV2-mhB27 antibody HF-nCoV-SPIKE-8D3 cells better binding, EC 50 which binds to 2.77 ⁇ g / mL, negative control without binding.
  • the SARS-CoV-2 RBD or S1 protein at a concentration of 1 ⁇ g/mL was coated on a 96-well plate, 100 ⁇ L per well, and coated overnight at 4°C. The plate was washed the next day and blocked at room temperature for 1 hour, then 100 ⁇ L of 0.08 ⁇ g/mL ACE2 protein (source: Beijing Yiqiao Shenzhou Technology Co., Ltd., the same below) and different concentrations of CoV2-mhB27 antibody (2500ng/mL, 625ng/mL, 156.3ng/mL, 39.1ng/mL, 9.8ng/mL and 2.4ng/mL) were incubated together.
  • Inhibition rate PI% (OD blank- OD sample ) / OD blank ⁇ 100%, where OD blank represents the OD value of the normal coating with only ACE2 and no antibody group, and OD sample represents the detection of normal coating with ACE2 and antibody at the same time Group OD value.
  • the results are shown in Figure 4.
  • the ACE2 protein can bind to the RBD and S1 protein of the coated SARS-CoV-2, and the CoV2-mhB27 antibody can effectively compete for the binding of the ACE2 protein to the RBD and S1 protein.
  • the competition EC 50 is 44.0, respectively. ng/mL and 24.0ng/mL.
  • Lennti-X 293 (source: Clontech) was used to package pseudovirus expressing the full-length SARS-CoV-2 S protein.
  • a total of 62 ⁇ g of PSD, pWPXL-Luc and pCMV3-SARS-CoV-2-S plasmid (source: Shenzhou Cell Engineering Co., Ltd.) were mixed in a ratio of 3:4:2, and 72 ⁇ L of Sinofection TF02 (source: Beijing) Yiqiao Shenzhou Technology Co., Ltd.) transfection reagent. After mixing, let it stand at room temperature for 10 minutes, and then add it to Lenti-X 293 cells. Place the cell plate in a 37°C, 5% CO 2 incubator for 6 hours and then change the medium. After culturing for 48 hours, the supernatant was collected, and the cell debris was removed by filtration with a 0.45 ⁇ m filter membrane to obtain a pseudovirus solution, which was stored at -80°C.
  • TCID 50 values Use the limiting dilution method to perform 10-fold gradient dilution of the virus, set a total of 10 virus concentrations, each with 6 replicate wells.
  • the 96-well plate was seeded with a density of 3 ⁇ 10 4 cell/mL overexpressing ACE2 293FT cells (293FT-ACE2, source: Shenzhou Cell Engineering Co., Ltd., the same below) suspension, 100 ⁇ L/well.
  • Add 50 ⁇ L of the virus in gradient dilution to each well use the cell culture medium as a negative control, mix well, and place it in a 37°C, 5% CO 2 incubator for 24 hours. After incubation, add 5 ⁇ passive lysis buffer (source: Promega), 30 ⁇ L/well, and mix well to lyse the cells. Take 10 ⁇ L / white bottom 96 well bore into the fluorescent signal is detected, calculates Reed-Muench method TCID 50 values.
  • CoV2-mhB27 antibody 2000ng/mL, 571.4ng/mL, 163.3ng/mL, 46.6ng/mL, 13.3ng/mL, 3.8ng/mL, 1.1ng/mL, 0.31 ng/mL and 0.089ng/mL
  • 50 ⁇ L/well 50 ⁇ L/well.
  • 100 TCID 50 pseudovirus was used as a positive control, and the virus-free and antibody-free group was used as a negative control. After mixing, incubate in a 37°C, 5% CO 2 incubator for 1 hour.
  • the amino acid sequence of the heavy chain variable region (SEQ ID NO: 8) and the amino acid sequence of the light chain variable region (SEQ ID NO: 9) of the CoV2-mhB27 neutralizing antibody were deduced.
  • SEQ ID NO: 10-15 and Table 1 The light chain and heavy chain CDRs of the above antibodies are directly transplanted into the finally obtained humanized antibody CoV2-HB27 in the subsequent humanization step.
  • the classical CDR transplantation method is used to humanize the mouse antibody [8,9] .
  • the similarity with the murine light chain and heavy chain variable regions is more than 50%
  • the framework regions of the light chain and heavy chain variable regions are similar to the amino acid sequences of the framework regions of the light chain and heavy chain variable regions of the antibody to be modified
  • An antibody with a sex ratio of more than 50% is used as a humanized template, and the three CDR sequences of the light chain or heavy chain of the mouse antibody are replaced in the corresponding CDR amino acid sequence in the humanized template.
  • the human template for the light chain variable region transplantation of CoV2-mhB27 was selected as IGKV3D-11*02, which is similar to CoV2.
  • the homology of the light chain of mhB27 is 62.8%; the human template of the variable region of the heavy chain is IGHV3-21*01, which has a homology of 78.9% with the heavy chain of CoV2-mhB27.
  • the key points of the mouse-derived framework region play a vital role in maintaining the stability of the CDR spatial structure, the key points need to be backmutated to the corresponding amino acids of the mouse antibody.
  • the 42nd position of the light chain was backmutated to F
  • the 71th position was backmutated to V
  • the 83th position was backmutated to S
  • the 88th position was backmutated to S
  • the 103rd position was backmutated to F
  • the back mutation at position 3 was K
  • the back mutation at position 49 was R
  • the back mutation at position 54 was A
  • the back mutation at position 86 was T.
  • Humanized antibody CoV2-HB27 was obtained by CDR humanization transplantation and framework region back mutation.
  • the amino acid sequences of the heavy chain and light chain variable region are shown in SEQ ID NO: 22/23; its heavy chain containing signal peptide
  • the amino acid sequence of the light chain and the light chain are shown in SEQ ID NO: 18/19, respectively, which respectively include the heavy chain/light chain signal peptide amino acid sequence (SEQ ID NO: 20/21) connected in sequence; the humanized antibody heavy chain/light chain
  • the amino acid sequence of the variable region of the chain (SEQ ID NO: 22/23); the constant region of the humanized antibody is the human IgG1 heavy chain constant region/human kappa light chain constant region sequence (SEQ ID NO: 32/33).
  • the CoV2-HB27 heavy chain variable region nucleotide sequence (SEQ ID NO: 30) was obtained by the method of full gene synthesis. Inserted into the pSE vector digested with ScaI+NheI (source: Fermentas, the same below) with heavy chain signal peptide (SEQ ID NO: 28) and heavy chain IgG1 constant region (SEQ ID NO: 32) by In-fusion method The CoV2-HB27 heavy chain (SEQ ID NO: 26) expression vector was obtained.
  • the nucleotide sequence of CoV2-HB27 light chain variable region (SEQ ID NO: 31) was obtained by the method of whole gene synthesis. Inserted into pSE digested with ScaI+BsiWI (source: Fermentas) with light chain signal peptide (SEQ ID NO: 29) and light chain kappa constant region nucleotide sequence (SEQ ID NO: 33) by In-fusion method.
  • the CoV2-HB27 light chain (SEQ ID NO: 27) expression vector was obtained from the vector.
  • the plasmid was extracted and transfected into HEK-293 cells (source: Invitrogen, the same below), cultured and expressed for 7 days, and purified by a protein A purification column to obtain high-purity antibodies.
  • SARS-CoV-2 RBD protein 777.8ng/mL, 259.3ng/mL, 86.4ng/mL, 28.8ng/mL, 9.6ng/mL and 3.2ng/mL
  • S1 protein 21000ng/mL, 7000ng/mL, 2333.3ng/mL, 777.8ng/mL, 259.3ng/mL, 86.4ng/mL, 28.8ng/mL, 9.6ng/mL and 3.2ng/mL
  • ECD protein 21000ng/mL, 7000ng/mL , 2333.3 ng/mL, 777.8 ng/mL, 259.3 ng/mL, 86.4 ng/mL, 28.8 ng/mL and 9.6 ng/mL
  • Example 2.2 to detect the ability of the humanized antibody to compete for the binding of the ACE2 receptor to the SARS-CoV-2 RBD protein.
  • the biomolecule interaction analysis system (model: OctetRED96e, manufacturer: Fortebio) was used to determine the humanized antibody CoV2-HB27 and biotinylated SARS-CoV-2 RBD and S1 protein (source: Beijing Yiqiao Shenzhou Technology Co., Ltd.) Binding affinity.
  • Select SA Sensor add 2 ⁇ g/mL of biotinylated SARS-CoV-2 RBD and S1 protein after 60s of equilibration, and then equilibrate again for 100s to wash away unbound protein.
  • CoV2-HB27 has high affinity with SARS-CoV-2 RBD and S1 protein.
  • the affinity of CoV2-HB27 to the SARS-CoV-2 RBD protein is 3.9E-11M, the binding constant is 3.7E+05 1/Ms, the dissociation constant is 1.4E-05 1/s, and R 2 is 1.000; and SARS- The affinity of CoV-2 S1 protein is 3.7E-10M, the binding constant is 1.1E+06 1/Ms, the dissociation constant is 3.9E-04 1/s, and R 2 is 0.997.
  • the specific kinetic characteristic parameter curve is shown in Figure 8.
  • CoV2-HB27 (500ng/mL, 200ng/mL, 80ng/mL, 32ng/mL, 12.8ng/mL, 5.12ng/mL, 2.05ng/mL, 0.82ng/mL and 0.33 ng/mL) the ability to neutralize 100TCID50SARS-CoV-2 pseudovirus in 293FT-ACE2 cells.
  • the results are shown in Figure 9.
  • CoV2-HB27 can effectively neutralize the pseudovirus of SARS-CoV-2 in a concentration-dependent manner, with a neutralization IC 50 of 5.9 ng/mL.
  • SDS-PAGE SDS polyacrylamide gel electrophoresis
  • SEC-HPLC size-exclusion high performance liquid chromatograph
  • SEC-HPLC operation steps are: (1) Instrument: liquid chromatography system (Agilent company, model: Agilent1260), hydrophilic silica gel high-performance molecular exclusion chromatography column (Tosoh company, model: TSK-GEL G3000SW XL (7.8 ⁇ 300mm, 5 ⁇ m)); (2) Mobile phase: 200mM NaH 2 PO 4 , 100mM Arginine, pH 6.5; (2) Sample amount is 80 ⁇ g; (3) Detection wavelength is 280nM, analysis time is 30min, flow rate is 0.5mL/min , The column temperature is 25°C; (4) Calculate the ratio of each peak according to the area normalization method.
  • Instrument liquid chromatography system (Agilent company, model: Agilent1260), hydrophilic silica gel high-performance molecular exclusion chromatography column (Tosoh company, model: TSK-GEL G3000SW XL (7.8 ⁇ 300mm, 5 ⁇ m)); (2) Mobile phase: 200mM
  • the DLS test result of CoV2-HB27 showed that the radius was 5.8nM and the percent dispersion (%Pd) was 9.8%, indicating that the CoV2-HB27 particles were small, the size of normal IgG1 antibody particles, and the uniformity was good (Table 3).
  • DFS Differential scanning fluorimetry
  • Instrument Uncle system (Unchained Labs, Model: UNCLE-0330); (2) The sample volume is 9 ⁇ L; (3) The detection parameters are set: the temperature range is 25°C ⁇ 95°C, the heating speed Incubate at 0.3°C/min for 30s at each temperature; (4) Use UNcle Analysis software to analyze the data, take the midpoint value of the internal fluorescence curve under UV266 as T m , and take the aggregate formed by the static light scattering signal under UV266/Blue473 The polymerization start temperature of the change curve is Tagg 266 and Tagg 473.
  • IgG1 antibody has asparagine (Asn) deamidation, lysine (Lys) glycation, methionine (Met) oxidation, etc., so there will be uneven charge, showing acidic and basic isomers .
  • CEX-HPLC cation exchange high performance liquid chromatograph
  • cIEF capillary isoelectric focusing
  • CEX-HPLC operation steps (1) Instrument: liquid chromatography system (Agilent company, model: Agilent1260), cation exchange chromatography column (Thermo company, model: ProPac TM WCX-10 (4 ⁇ 250mm, 5 ⁇ M)); (2) ) Mobile phase A: buffer A, pH 5.6 (Thermo company, product number: 083273); (3) Mobile phase B: buffer B, pH 10.2 (Thermo company, product number: 083275); (4) The sample amount is 80 ⁇ g; ( 5) The detection wavelength is 280nM, the analysis time is 50min, the flow rate is 0.5mL/min, and the column temperature is 25°C; (6) The ratio of each peak is calculated by the area normalization method.
  • Instrument imaging capillary electrophoresis instrument (Proteinsimple, model: iCE3); (2) Take 10 ⁇ L of 5mg/ml sample and 8 ⁇ L Pharmalyte 3-10, 70 ⁇ L 1% methyl cellulose (MC), 2 ⁇ L PI marker And ddH 2 O was prepared into an analysis solution with a total volume of 200 ⁇ L; (3) The sample was placed in an iCE3 instrument, 1500V was pre-focused for 1 minute, and then 3000V was collected for 6 minutes; (4) Chrom Perfect software was used to analyze the data.
  • the CoV2-HB27 sample was stored at -80°C for 3 hours and then transferred to 45°C to thaw for 1 hour. The freeze-thaw cycle was repeated five times.
  • the 11.1mg/mL CoV2-HB27 sample was concentrated to 26.0mg/mL, 51.4mg/mL, 85.5mg/mL, 103.9mg/mL using a 50kDa ultrafiltration tube, and the purity of the sample was analyzed by SDS-PAGE and SEC-HPLC. Use DLS to analyze the change of sample particle size, and the specific steps are the same as 5.1.
  • Example 2.2 show that CoV2-mhB27 can compete for the binding of ACE2 receptor to SARS-CoV-2 RBD and S1 protein. Crystallization by cryo-electron microscopy showed that residues 437-508 are the key amino acid residues required for the binding of SARS-CoV-2 RBD to ACE2 [10] . Based on the above information, it is speculated that after CoV2-mhB27 is combined with RBD, it will form a steric conflict with the structural conformation of ACE2.
  • 17 residue sites located in the ACE2 binding region and its vicinity were selected and mutated into other residue types that are quite different from the original residue types, resulting in 15 mutants, namely E340R, T345Y, V367F, K378D, T385Y, N439R, N440Y, Y449A/N450, Y489R, T500Y, Y505E, A372Y, S375Y, D405R/R408, and V503Y.
  • SARS-CoV-2 RBD-His was used as a template (sequence source: https://www.gisaid.org/), PCR was used for site-directed mutation, and sequencing verification was performed.
  • the mutant and wild-type (WT) SARS-CoV-2 RBD proteins were transiently transfected and the binding ability of CoV2-mhB27 antibody to the mutant protein was detected by ELISA.
  • the ELISA readings of WT SARS-CoV-2 RBD were used as the standard to standardize the test results of each antibody.
  • the highest antibody binding reading (set as 100%) was used to further normalize the ELISA binding signal for the mutant.
  • the ELISA binding signal of mhB27 for a specific mutant drops below 75% relative to WT SARS-CoV-2 RBD, this residue site is defined as a significant binding epitope.
  • the ELISA binding signal of CoV2-mhB27 against a specific mutant drops below 50%, it is defined as a highly significant epitope.
  • N439 and T500 in SARS-CoV-2 RBD are highly significant epitopes of CoV2-mhB27.
  • nucleotide mutations in the constant region of the IgG1 subtype were carried out with reference to the literature [11] to obtain the genetically engineered heavy chain IgG1 constant region nucleotide sequence (Fd6-IgG1, SEQ ID NO:44).
  • the CoV2-HB27-Fd6-IgG1 heavy chain sequence (SEQ ID NO: 46) was obtained by PCR, which includes the heavy chain signal peptide nucleotide sequence (SEQ ID NO: 28), and the heavy chain variable region nucleotide sequence (SEQ ID NO: 28). ID NO: 30) and Fd6-IgG1 constant region nucleotide sequence (SEQ ID NO: 44).
  • the expression vector containing CoV2-HB27-Fd6-IgG1 heavy chain (SEQ ID NO: 46) was inserted into the pSE vector digested with HindIII+XbaI by In-fusion method.
  • CoV2-HB27-Fd6-IgG1 heavy chain (SEQ ID NO: 46) expression vector and CoV2-HB27 light chain (SEQ ID NO: 27) expression vector plasmids were extracted, transfected into HEK-293 cells and cultured and expressed for 7 days, using protein Purification by purification column A obtains CoV2-HB27-Fd6-IgG1 antibody that reduces Fc function.
  • CoV2-HB27 heavy chain (SEQ ID NO: 26) expression vector and CoV2-HB27 light chain (SEQ ID NO: 27) expression vector plasmids were extracted, transfected into HEK-293 (fut8 gene knockout) cells and cultured and expressed for 7 days. Purified by a protein A purification column, the CoV2-HB27-Ae0-IgG1 antibody of defucosylated IgG1 subtype was obtained.
  • nucleotide mutations in the constant region of the IgG1 subtype were carried out with reference to the literature [12,13] to obtain the genetically engineered heavy chain IgG1 constant region nucleotide sequence (Fe4-IgG1, SEQ ID NO: 48).
  • the CoV2-HB27-Fe4-IgG1 heavy chain sequence (SEQ ID NO: 50) was obtained by PCR, which contains the heavy chain signal peptide nucleotide sequence (SEQ ID NO: 28), and the heavy chain variable region nucleotide sequence (SEQ ID NO: 28). ID NO: 30) and Fe4-IgG1 constant region nucleotide sequence (SEQ ID NO: 48).
  • the CoV2-HB27-Fe4-IgG1 heavy chain (SEQ ID NO: 50) expression vector was inserted into the pSE vector digested with HindIII+XbaI by In-fusion method.
  • CoV2-HB27-Fe4-IgG1 heavy chain (SEQ ID NO: 50) expression vector and CoV2-HB27 light chain (SEQ ID NO: 27) expression vector plasmids were extracted and transfected into HEK-293 (fut8 gene knockout) cells for culture After 7 days of expression, the protein A purification column was used to obtain CoV2-HB27-Fe4-IgG1 antibody with enhanced Fc function.
  • Example 8 Fc function of different forms of humanized antibody CoV2-HB27
  • Avidin protein (source: Thermo, the same below) at a concentration of 10 ⁇ g/mL was coated on a 96-well plate, 100 ⁇ L per well, and coated overnight at 2-8°C. Wash the plate the next day. After blocking at room temperature for 1 hour, add 100 ⁇ L of 5 ⁇ g/mL biotin-labeled CD16a-AVI-His(V158)+BirA protein (source: Beijing Yiqiao Shenzhou Technology Co., Ltd.), incubate at room temperature for 1 hour and then wash the plate .
  • Avidin protein at a concentration of 10 ⁇ g/mL was coated on a 96-well plate, 100 ⁇ L per well, and coated overnight at 2-8°C. Wash the plate the next day and block for 1 hour at room temperature.
  • CoV2-HB27 antibodies with different Fc functional forms were added, and the antibody concentrations were 40000ng/mL, 10000ng/mL, 2500ng/mL, 625ng/mL, 156.3ng/mL, 39.1ng/mL and 9.77ng/mL.
  • the plate was washed to remove unbound antibodies, and goat anti-human IgG F(ab)2/HRP was added to incubate and the plate was washed repeatedly, and the substrate color development solution was added for color development. After termination, the microplate reader reads OD 450 .
  • Avidin protein at a concentration of 10 ⁇ g/mL was coated on a 96-well plate, 100 ⁇ L per well, and coated overnight at 2-8°C. The plate was washed the next day and sealed at room temperature for 1 hour, and 100 ⁇ L of biotin-labeled CD64-AVI-His+BirA protein (source: Beijing Yiqiao Shenzhou Technology Co., Ltd.) was added at a concentration of 0.5 ⁇ g/mL, and the plate was washed after incubating for 1 hour at room temperature.
  • CoV2-HB27 antibodies with different Fc functional forms Add 100 ⁇ L of CoV2-HB27 antibodies with different Fc functional forms, and the antibody concentration is 2500ng/mL, 625ng/mL, 156.3ng/mL, 39.1ng/mL, 9.77ng/mL, 2.44ng/mL, 0.61ng/mL, 0.15 ng/mL, 0.04ng/mL and 0.01ng/mL.
  • the plate was washed to remove unbound antibodies, and goat anti-human IgG F(ab)2/HRP was added to incubate and the plate was washed repeatedly. Finally, the substrate color solution was added for color development. After termination, the plate reader reads OD 450 .
  • the Fe4-IgG1 form antibody with enhanced Fc function has the strongest binding ability to CD64, which is better than the defucosylated Ae0-IgG1 form antibody and CoV2-HB27 antibody of IgG1 subtype; Fd6-IgG1 antibody with reduced Fc function only weakly binds to CD64.
  • CoV2-HB27 antibodies with different concentrations of different Fc functional forms were respectively coated on 96-well plates, 100 ⁇ L/well, coated overnight at 4°C, antibody coating concentrations were 40000ng/mL, 10000ng/mL, 2500ng/mL, 625ng /mL, 156.3ng/mL, 39.1ng/mL and 9.77ng/mL.
  • the plate was washed the next day and sealed at room temperature for 1 hour, then 5 ⁇ g/mL of C1q complement protein (source: Beijing Yiqiao Shenzhou Technology Co., Ltd.) was added, 100 ⁇ g/well, and incubated for 1 hour.
  • the Fe4-IgG1 form antibody with enhanced Fc function has the strongest binding ability to C1q, which is better than the defucosylated Ae0-IgG1 form antibody and CoV2-HB27 antibody of IgG1 subtype; Fd6-IgG1 antibody with reduced Fc function only weakly binds to C1q.
  • the HEK293FT monoclonal cell line stably expressing the full-length SARS-CoV-2 protein (HEK293FT-SARS-CoV-2-S, source: Shenzhou Cell Engineering Co., Ltd., the same below) was used as the target cell to stably transfect CD16AV and NFAT -Luc2P Jurkat cells (Jurkat-NFAT/Luc2P-CD16AV) are effector cells, and the ADCC function of humanized antibodies is detected by the reporter gene method.
  • target cells with a density of 1 ⁇ 10 5 cell/mL and effector cells with an equal volume and an equal density were inserted at 50 ⁇ L/well. Then add 50 ⁇ L of CoV2-HB27 antibody and H7N9-R1 negative control antibody in different Fc functional forms.
  • CoV2-HB27-Ae0-IgG1 CoV2-HB27-He5-IgG1 antibody was added at a concentration of 6.25ng/mL, 0.78ng/mL, 0.097ng/mL, 0.012ng/mL, 0.0015ng/mL and 0.00019ng/mL, the rest The antibody concentration was 50ng/mL, 6.25ng/mL, 0.78ng/mL, 0.097ng/mL, 0.012ng/mL, 0.0015ng/mL and 0.00019ng/mL. After mixing, incubate in a 37°C, 5% CO 2 incubator for 6 hours. Finally, add 5 ⁇ passive lysis buffer, 30 ⁇ L/well, and mix well to lyse the cells.
  • the Fe4-IgG1 form antibody with enhanced Fc function can mediate the strongest ADCC effect, which is better than the defucosylated Ae0-IgG1 form antibody And IgG1 subtype antibody mediated ADCC effect; Fd6-IgG1 form antibody that reduces Fc function has no ADCC effect.
  • Jurkat cells With HEK293FT-SARS-CoV-2-S as target cells, Jurkat cells (Jurkat-NFAT/Luc2P-CD32A, Jurkat-NFAT/Luc2P-CD32B or Jurkat-NFAT) stably transfected with CD32A, CD32B or CD64 and NFAT-Luc2P /Luc2P-CD64) are effector cells, and the reporter gene method is used to detect the ADCP function mediated by humanized antibodies.
  • target cells with a density of 1 ⁇ 10 5 cell/mL and effector cells with an equal volume and an equal density were inserted at 50 ⁇ L/well. Then add 50 ⁇ L of CoV2-HB27 antibody and H7N9-R1 negative control antibody in different Fc functional forms.
  • the antibody concentration is 50ng/mL, 6.25ng/mL, 0.78ng/mL, 0.097ng/mL, 0.012ng/mL, 0.0015ng /mL, 0.00019ng/mL, 0.000024ng/mL and 0.000003ng/mL;
  • the antibody concentration is 6.25ng/mL, 0.78ng/mL, 0.097ng/mL, 0.012 ng/mL, 0.0015ng/mL, 0.00019ng/mL, 0.0000024ng/mL and 0.000003ng/mL.
  • WST-8 method was used to detect the CDC function of humanized antibodies.
  • target cells with a density of 2 ⁇ 10 6 cells/mL were inserted at 50 ⁇ L/well.
  • 50 ⁇ L of rabbit complement (source: One lambda) and CoV2-HB27 antibodies of different Fc functional forms and set up detection blank holes (no cells), positive control (only inoculated cells) control and H7N9-R1 negative control antibody groups antibodies
  • the added concentrations were 20ng/mL, 4ng/mL, 0.8ng/mL, 0.16ng/mL, 0.032ng/mL, 0.0064ng/mL and 0.00128ng/mL.
  • Example 9 Evaluation of mouse pharmacokinetics of humanized antibody CoV2-HB27 with different Fc functional forms
  • mice choose C57BL/6 mice (a total of 6 mice, male and female, source: Beijing Weitong Lihua Experimental Animal Technology Co., Ltd.), a single tail vein injection of CoV2-HB27, the dose of 5mg/kg, the volume of administration It is 10mL/kg.
  • 30min, 1h, 3h, 6h, 10h, 24h, 32h, 48h, 72h, 96h, 120h, 168h, 240h, 336h, 504h and 672h after administration all mice were subjected to orbital blood sampling and centrifugation Take the serum.
  • the blood drug concentration was detected by ELISA method, and the non-compartmental model (NCA) in Phoenix-WinNonlin 8.1 software was used to calculate the pharmacokinetic parameters.
  • NCA non-compartmental model
  • C57BL/6 mice (a total of 6 mice, half male and half male, source: Beijing Weitong Lihua Experimental Animal Technology Co., Ltd.) were selected to give CoV2-HB27-Fd6-IgG1 antibody by a single tail vein injection at a dose of 5 mg/ kg, the administration volume is 10mL/kg.
  • 30min, 1h, 3h, 6h, 10h, 24h, 32h, 48h, 72h, 96h, 120h168h, 240h, 336h, 504h and 672h after administration blood was collected from the orbit of all mice, and serum was collected by centrifugation .
  • the blood drug concentration was detected by ELISA, and the non-compartmental model (NCA) in Phoenix-WinNonlin 6.4 software was used to calculate the pharmacokinetic parameters.
  • NCA non-compartmental model
  • mice were in normal condition, and the drug-time curve is shown in Figure 19.
  • the drug concentration in the mice continued to decrease over time, with a rapid decrease in the early stage, but a slower change in a longer period of time, and there was no obvious gender difference.
  • the pharmacokinetic parameters are shown in Table 10.
  • the average in vivo exposure C max and AUC last were 115.04 ⁇ g/mL and 11159.82h ⁇ g, respectively /mL, the average half-life t 1/2 is 320.00h, and the clearance rate Cl is 0.23mL/h/kg.

Abstract

La présente invention relève du domaine de la technologie de l'immunité cellulaire, et concerne un anticorps monoclonal humanisé neutralisant le SARS-CoV-2. Ledit anticorps peut bloquer la liaison d'une protéine de spicule du SARS-CoV-2 (protéine S) et d'un récepteur d'ACE2, et neutraliser de manière efficace une invasion de cellules par le virus du SARS-CoV-2. L'anticorps humanisé neutralisant produit peut être utilisé en tant que médicament d'anticorps spécifique pour prévenir et traiter des maladies infectieuses aiguës des voies respiratoires provoquées par le virus du SARS-CoV-2.
PCT/CN2021/089748 2020-04-28 2021-04-26 Anticorps neutralisant sars-cov-2, préparation et utilisation associées WO2021218879A1 (fr)

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