Antibody capable of specifically recognizing MASP3 and application thereof

Abstract

The invention relates to the field of biological medicine, in particular to a specific recognition MASP3 antibody and application thereof, and the antibody has high human MASP3 affinity and alternative pathway inhibitory activity. The antibody is used for preparing a medicament for treating autoimmune diseases, transplantation-related diseases, inflammatory diseases, hematological diseases, hemolytic diseases, angiogenesis-dependent diseases and / or virus infectious diseases.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Chinese patent application with application number 202310682866.4, application date 2023.06.09, and invention name “Antibodies specifically recognizing MASP3 and their applications”, and the entire contents of the application are incorporated herein by reference.

[0003] References to Electronic Sequence Listings

[0004] The contents of the electronic sequence listing (text name: Text name: M3-4.xml, recording date: 2023.06.07, size: 33KB) are incorporated herein by reference in its entirety. Technical Field

[0005] The present application relates to antibodies or antigen-binding fragments that specifically bind to MASP3, as well as preparation methods and uses thereof. Background Art

[0006] The complement system plays a vital role in both innate and adaptive immune responses. Complement removes immune complexes and cell debris, and rapidly produces highly efficient and strictly regulated inflammatory and cytolytic immune responses to infectious organisms (including bacteria, viruses, and protozoan parasites) (Dunkelberger, Jason R, and Wen-Chao Song. Cell research vol. 20, 1 (2010): 34-50.). Complement activation leads to a proteolytic cascade, ultimately leading to inflammatory cell recruitment, phagocytosis, and cell lysis (Kjaer, Troels R et al. Molecular immunology vol. 56, 4 (2013): 413-22.). It also produces anaphylatoxins (C3a, C4a, C5a) that can effectively promote inflammatory responses, as well as opsonins (C3b and C4b) that cover the surface of pathogens and mediate phagocytosis. The endpoint of the cascade reaction is the assembly of the membrane attack complex (MAC) on the cell membrane, forming a pore that leads to cell lysis (Dunkelberger, Jason R, and Wen-Chao Song. Cell research vol. 20, 1 (2010): 34-50.).

[0007] The complement system can be activated through three pathways: the classical pathway (CP), the alternative pathway (AP), and the lectin pathway (LP). The classical pathway starts with C1q. When C1q recognizes some target molecules (such as immune complexes or surface-bound pentraxin), its conformation changes, allowing C1q to interact with C1r and C1s to form activated C1qr2s2 (Carroll, MC. Annual review of immunology vol. 16 (1998): 545-68.). The enzyme active site is on C1s. Subsequently, the activated C1qr2s2 cleaves C4 and subsequent C2 to generate the C3 convertase C4b2a in the classical pathway. C4b2a can induce proteolytic activity and activate the common terminal pathway (Sim, RB, and SA Tsiftsoglou. Biochemical Society transactions vol. 32, Pt 1 (2004): 21-7.).

[0008] The lectin pathway can be triggered by circulating pattern recognition receptors (PRRs) that recognize carbohydrates on the surface of microorganisms, including mannose-binding lectin (MBL), collectins, and ficolins. Ficolins are PRRs with fibrin-like domains, such as M-ficolin (ficolin-1), L-ficolin (ficolin-2), and H-ficolin (ficolin-3). MBL-related serine proteases (MASP-1 and MASP-2) are evolutionarily related to C1r and C1s and have similar functions. MBL forms a complex with MASPs, then cleaves C4 and C2 to form the C3 convertase C4b2a in the lectin pathway (Garred, Peter et al. Immunological reviews vol. 274, 1 (2016): 74-97.).

[0009] When C3b appears on the surface of the activator, the alternative pathway can be initiated (Lachmann, Peter J. Immunobiology vol. 223, 8-9 (2018): 519-523.). After C3b captures FB, the FB bound to C3b can be cleaved by FD into Ba and Bb. In the blood, MASP-3 can cleave pro-PD and continue to provide PD for the alternative pathway, even before any activation signal appears (Oroszlán, Gábor et al. Journal of immunology (Baltimore, Md.: 1950) vol. 196, 2 (2016): 857-65.; Dobó, József et al. Scientific reports vol. 631877. 18 Aug. 2016). C3b and Bb form the C3 convertase C3bBb in the alternative pathway, which can cleave more C3, thereby producing more C3 convertase complexes. This positive feedback mechanism can amplify complement activation initiated by the classical or alternative pathway (Harboe, M et al. Clinical and experimental immunology vol. 138, 3 (2004): 439-46.). The alternative pathway can also be self-activated by the so-called "slow transport" mechanism (Pangburn, MK et al. The Journal of experimental medicine vol. 154, 3 (1981): 856-67.). C3 is slowly hydrolyzed in the circulation to generate C3 (H2O) similar to C3b. After C3 (H2O) binds to FB, it is cut by FD. C3 (H2O) Bb is a liquid C3 convertase that can generate C3b near any surface. On the surface of its own cells, it can be protected from complement-mediated damage by different complement inhibitors. On unprotected surfaces (such as bacterial surfaces), deposited C3b can initiate the amplification loop in the alternative pathway, leading to complete complement activation.

[0010] When the density of deposited C3b reaches a certain point, C3b forms C5 convertase (C4b2aC3b or C3bBbC3b) with C3 convertase (C4b2a or C3bBb) (Mannes, Marco et al. Blood vol.137, 4 (2021): 443-455.; Roumenina, Lubka T. Blood vol.137, 4 (2021): 431-432.). From this point on, the three activation pathways enter the common terminal pathway (TP). C5 convertase cleaves C5 into C5a and C5b, of which C5a is a very effective anaphylatoxin, while C5b combines with C6 and C7 to form C5b67, exposing the membrane binding site, non-specifically binding to the nearby cell membrane, and capturing C8 and multiple C9 molecules to form the C5b6789n complex, the membrane attack complex (MAC). MAC inserted into the cell membrane can form hydrophilic pores through the membrane, leading to lysis and destruction of target cells (Tegla, Cosmin A et al. Immunologic research vol. 51, 1 (2011): 45-60).

[0011] The complement system is a very effective mechanism for cell killing and initiating inflammation. To prevent overactivation, the complement system is strictly controlled by different inhibitory mechanisms. A delicate balance between activation and inhibition is necessary to maintain inflammatory homeostasis in the human body. When this balance is disrupted for any reason, self-organization is disrupted and serious diseases occur. There are many clinical diseases involving uncontrolled (or sometimes insufficient) complement activation. Often, the etiology of these diseases is complex, and unnecessary complement activation is only one of the pathological factors. However, evidence obtained from various disease models suggests that preventing or inhibiting pathological complement activation may be a promising treatment approach (Dobó, József et al. Frontiers in immunology vol. 91851.).

[0012] Inappropriate or uncontrolled activation of the complement system has been identified in many diseases. Some of these are mainly rare complement-mediated diseases, such as paroxysmal nocturnal hemoglobinuria, C3 glomerulonephritis, and atypical hemolytic uremic syndrome. Complement also plays a role in various multifactorial diseases that affect millions of people worldwide, such as ischemia-reperfusion injury (myocardial infarction, stroke) (Hart, Melanie L et al. "Journal of immunology (Baltimore, Md.: 1950) vol. 174, 10 (2005): 6373-80.);), age-related macular degeneration (Geerlings, Maartje Jet al. Molecular immunology vol. 84 (2017): 65-76.) and several neurodegenerative diseases (Hong, Soyon et al. Science (New York, NY) vol. 352, 6286 (2016): 712-716.; Sekar, Aswin et al. Nature vol. 530, 7589 (2016): 177-83.).

[0013] At present, there are reports on antibodies targeting MASP3, for example, Chinese patent application CN109715209A discloses anti-MASP3 antibody OMS906 (used as a control antibody in the examples of this application) and its application. However, there are no antibody drugs targeting MASP3 on the market, so it is urgent to develop antibody drugs targeting MASP3.

[0014] The disclosures of all publications, patents, patent applications, and published patent applications mentioned herein are incorporated by reference in their entirety.

[0015] Application Overview

[0016] In some embodiments, an isolated anti-MASP3 antibody is provided, comprising: H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:13, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:16, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:19.

[0017] In some embodiments, any of the isolated anti-MASP3 antibodies described above comprises: H , comprising the amino acid sequence shown in SEQ ID NO: 22 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO: 22; and V L , which comprises the amino acid sequence shown in SEQ ID NO:26 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO:26.

[0018] In some embodiments, an isolated anti-MASP3 antibody is provided that competes with any of the above isolated anti-MASP3 antibodies for specific binding to MASP3. In some embodiments, an isolated anti-MASP3 antibody is provided that specifically binds to the same epitope as any of the above isolated anti-MASP3 antibodies.

[0019] In some embodiments, any of the isolated anti-MASP3 antibodies described above, the isolated anti-MASP3 antibody comprises an Fc fragment. In some embodiments, the isolated anti-MASP3 antibody is a full-length IgG antibody. In some embodiments, the isolated anti-MASP3 antibody is a full-length IgG1, IgG2, IgG3 or IgG4 antibody. In some embodiments, the isolated anti-MASP3 antibody is a chimeric, fully human or humanized antibody. In some embodiments, the isolated anti-MASP3 antibody is an antigen-binding fragment selected from the group consisting of Fab, Fab', F(ab)'2, Fab'-SH, single-chain Fv (scFv), Fv fragment, dAb, Fd, nanobody, diabody and linear antibody.

[0020] In some embodiments, an isolated nucleic acid molecule is provided, the nucleic acid molecule encoding any of the anti-MASP3 antibodies described above. In some embodiments, a vector is provided, the vector comprising any of the nucleic acid molecules described above. In some embodiments, a host cell is provided, the host cell comprising any of the anti-MASP3 antibodies described above, any of the nucleic acid molecules described above, or any of the vectors described above. In some embodiments, a method for preparing an anti-MASP3 antibody is provided, comprising: a) culturing any of the host cells described above under conditions effective for expressing the anti-MASP3 antibody; and b) obtaining the expressed anti-MASP3 antibody from the host cell.

[0021] In some embodiments, a method of treating a disease or condition in a desired individual is provided, comprising administering to the individual an effective amount of any of the anti-MASP3 antibodies described above. In some embodiments, use of any of the anti-MASP3 antibodies described above in the preparation of a pharmaceutical composition for treating a disease or condition in a desired individual is provided. In some embodiments, use of any of the anti-MASP3 antibodies described above or a pharmaceutical composition comprising an anti-MASP3 antibody in the preparation of a medicament for treating a disease or condition is provided. In some embodiments, the disease or condition is associated with complement activation, including autoimmune diseases, transplantation-related diseases, inflammatory diseases, blood diseases, coagulopathy, angiogenesis-dependent diseases, and / or viral infections or conditions. In some embodiments, the disease or disorder is selected from, for example, ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), paroxysmal nocturnal hemoglobinuria (PNH), secondary TMA after transplantation, Upshaw-Schulman syndrome, arthritis, traumatic brain injury, Aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection.

[0022] Also provided are pharmaceutical compositions, kits, and articles of manufacture comprising any of the anti-MASP3 antibodies described above.

[0023] Detailed description of this application

[0024] In one aspect, the present application provides anti-MASP3 antibody molecules. Through the combination of scFv phage library screening and appropriately designed biochemical and biological experiments, highly effective antibody molecules that can bind to human MASP3 and inhibit its activity have been identified. The results presented herein show that the antibodies in the present application can effectively inhibit the enzymatic activity of MASP3 and can inhibit the hemolysis mediated by the alternative pathway.

[0025] The anti-MASP3 antibodies provided herein include, for example, full-length anti-MASP3 antibodies, anti-MASP3 single-chain antibodies (scFvs), anti-MASP3 Fc fusion proteins, multispecific (e.g., bispecific) anti-MASP3 antibodies, anti-MASP3 immunoconjugates, and the like.

[0026] In another aspect, the present application provides an anti-MASP3 antibody, wherein the anti-MASP3 antibody comprises: a heavy chain variable domain (V H ), the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:13, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:16, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:19.

[0027] In another aspect, the present application provides an anti-MASP3 antibody, wherein the anti-MASP3 antibody comprises: H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 2, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 6, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 10; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:14, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:17, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:20.

[0028] In another aspect, the present application provides an anti-MASP3 antibody, wherein the anti-MASP3 antibody comprises V H , the V Hcomprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 3, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 7, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:15, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:18, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:21.

[0029] In another aspect, the present application provides an anti-MASP3 antibody, wherein the anti-MASP3 antibody comprises: H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:15, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:18, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:21.

[0030] Also provided are nucleic acids encoding anti-MASP3 antibodies, compositions comprising the anti-MASP3 antibodies, and methods of making and using the anti-MASP3 antibodies.

[0031] definition

[0032] As used herein, "treatment" or "treating" is a method of obtaining beneficial or desired results, including clinical results. For the purposes of this application, the beneficial or desired clinical results include, but are not limited to, one or more of the following: alleviating one or more symptoms caused by the disease, alleviating the extent of the disease, stabilizing the disease (e.g., preventing or delaying disease progression), preventing or delaying the spread of the disease (e.g., metastasis), preventing or delaying disease recurrence, delaying or slowing disease progression, improving the disease state, alleviating the disease (partially or completely), reducing the dose of one or more other drugs required to treat the disease, delaying disease progression, improving or enhancing quality of life, increasing body weight, and / or prolonging survival. At the same time, "treatment" also includes a reduction in the pathological consequences of the disease (e.g., inhibiting hemolysis, inhibiting thrombosis). The methods of the present application take into account any one or more aspects of these treatments.

[0033] The term "antibody" includes full-length antibodies and antigen-binding fragments thereof. Full-length antibodies include two heavy chains and two light chains. The variable regions of the light and heavy chains are responsible for antigen binding. The variable regions in the two chains usually include three hypervariable loops, known as complementarity determining regions (CDRs) (light chain (LC) CDRs include LC-CDR1, LC-CDR2 and LC-CDR3, and heavy chain (HC) CDRs include HC-CDR1, HC-CDR2 and HC-CDR3). The CDR boundaries of the antibodies or antigen-binding fragments disclosed herein can be defined or identified by the Kabat, Chothia or Al-Lazikani conventions (Al-Lazikani 1997; Chothia 1985; Chothia 1987; Chothia 1989; Kabat 1987; Kabat 1991). The three CDR regions of the heavy or light chain are inserted between flanking segments called framework regions (FRs), which are more highly conserved than the CDR regions and form a scaffold that supports the hypervariable loops. The constant regions of the heavy and light chains are not involved in antigen binding, but exhibit a variety of effector functions. Antibodies are classified based on the amino acid sequence of their heavy chain constant regions. The five major classes or isotypes of antibodies are IgA, IgD, IgE, IgG, and IgM, characterized by having α, δ, ε, γ, and μ heavy chains, respectively. Several major antibody classes are divided into subclasses, such as IgG1 (γ1 heavy chain), IgG2 (γ2 heavy chain), IgG3 (γ3 heavy chain), IgG4 (γ4 heavy chain), IgA1 (α1 heavy chain), or IgA2 (α2 heavy chain).

[0034] As described herein, the term "antigen-binding fragment" includes antibody fragments, such as diabodies, Fab, Fab', F(ab')2, Fv fragments, disulfide-stabilized Fv fragments (dsFv), (dsFv)2, bispecific dsFv (dsFv-dsFv'), disulfide-stabilized diabodies (dsdiabodies), single-chain Fv (scFv), scFv dimers (divalent diabodies), multispecific antibodies composed of antibody fragments comprising one or more CDRs, single-domain antibodies, nanobodies, domain antibodies, divalent domain antibodies, or any other antibody fragment that can bind to an antigen but does not contain a complete antibody structure. Antigen-binding fragments can bind to the same antigen as a parent antibody or a parent antibody fragment (such as a parent scFv). Antigen-binding fragments also include fusion proteins comprising the above-mentioned antibody fragments. In some embodiments, an antigen-binding fragment may include one or more CDRs from a specific human antibody, which are transplanted to the framework region from one or more different human antibodies.

[0035] As used herein, the term "epitope" refers to a specific group of atoms or amino acids on an antigen to which an antibody or antibody portion binds. If two antibodies or antibody portions exhibit competitive binding to an antigen, they are likely to bind to the same epitope on the antigen.

[0036] As used herein, a first antibody "competes" for binding to a MASP3 target with a second antibody when the first antibody inhibits binding of the second antibody to the MASP3 target by at least 50% (e.g., at least 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, or 99%) at equimolar concentrations, and vice versa. PCT Publication WO 03 / 48731 describes a high throughput antibody "epitope binning" method based on cross-competition.

[0037] As used herein, the terms "specifically bind", "specifically recognize" or "specific for" refer to a measurable and reproducible interaction, such as the binding of an antibody to a target that can determine the presence of the target in a heterogeneous population of molecules, including biomolecules. For example, an antibody can specifically recognize a target (which can be an epitope) means that the antibody binds to the target with higher affinity, avidity, more readily and / or more persistently than other targets. In some embodiments, an antibody that specifically recognizes an antigen reacts with one or more antigenic determinants of the antigen with an affinity that is at least 10 times greater than its binding affinity to other targets.

[0038] As used herein, an "isolated" anti-MASP3 antibody refers to an anti-MASP3 antibody that (1) is not related to naturally occurring proteins, (2) does not contain other proteins from the same source, (3) is expressed by cells of a different species, or (4) does not occur in nature.

[0039] As used herein, the term "isolated nucleic acid" refers to a nucleic acid of genomic, cDNA or synthetic origin or a combination thereof. Depending on its origin, the "isolated nucleic acid" is (1) unrelated to all or part of the polynucleotides in the "isolated nucleic acid" found in nature, (2) operably linked to polynucleotides that are not naturally associated with it, or (3) not present as part of a longer sequence in nature.

[0040] As used herein, the term "CDR" or "complementarity determining region" refers to the non-contiguous antigen binding sites found within the variable domains of heavy and light chain polypeptides. In the literature Kabat et al., J. Biol. Chem. 252: 6609-6616 (1977); Kabat et al., USDept. of Health and Human Services, "Sequences of proteins of immunological interest" (1991); Chothia et al., J. Mol. Biol. 196: 901-917 (1987); Al-Lazikani B. et al. al., J. Mol. Biol., 273: 927-948 (1997); MacCallum et al., J. Mol. Biol. 262: 732-745 (1996); Abhinandan and Martin, Mol. Immunol., 45: 3832-3839 (2008); Lefranc MPet These special regions have been described in, for example, Desmond et al., Dev. Comp. Immunol., 27: 55-77 (2003); and Honegger and Plückthun, J. Mol. Biol., 309: 657-670 (2001), wherein these definitions include overlaps or subsets of amino acid residues when compared to one another. However, any definition used to indicate the CDR of an antibody or a transplanted antibody or a variant thereof is included within the scope of the terms defined and used herein. Table 1 lists the positions of the amino acid residues included in the CDRs defined by the above-cited references for comparison. Algorithms and binding interfaces for CDR prediction are known in the art, including, for example, Abhinandan and Martin, Mol. Immunol., 45: 3832-3839 (2008); Ehrenmann F. et al., Nucleic Acids Res., 38: D301-D307 (2010); and Adolf-Bryfogle J. et al., Nucleic Acids Res., 43: D432-D438 (2015). The contents of the references cited in this paragraph are incorporated herein by reference in their entirety for use in this application and in one or more claims that may be included in this article.

[0041] Table 1: CDR definitions

[0042] <![CDATA[Kabat 1 ]]> <![CDATA[Chothia 2 ]]> <![CDATA[MacCallum 3 ]]> <![CDATA[IMGT 4 ]]> <![CDATA[AHo 5 ]]> <![CDATA[V H CDR1]]> 31-35 26-32 30-35 27-38 25-40 <![CDATA[V H CDR2]]> 50-65 53-55 47-58 56-65 58-77 <![CDATA[V H CDR3]]> 95-102 96-101 93-101 105-117 109-137 <![CDATA[V L CDR1]]> 24-34 26-32 30-36 27-38 25-40 <![CDATA[V L CDR2]]> 50-56 50-52 46-55 56-65 58-77 <![CDATA[V L CDR3]]> 89-97 91-96 89-96 105-117 109-137

[0043] 1 The amino acid residue numbers refer to the nomenclature of Kabat et al.

[0044] 2 The amino acid residue numbers refer to the nomenclature of Chothia et al.

[0045] 3 The amino acid residue numbers refer to the nomenclature of MacCallum et al.

[0046] 4 The amino acid residue numbers refer to the nomenclature of Lefranc et al.

[0047] 5 The amino acid residue numbers refer to the nomenclature of Honegger and Plückthun above.

[0048] The term "chimeric antibody" refers to an antibody in which a portion of the heavy chain and / or light chain is identical or homologous to a corresponding sequence in an antibody from a particular species or belonging to a particular antibody class or subclass, and the remainder of the chain(s) is identical or homologous to a corresponding sequence in an antibody from another genus or belonging to another antibody class or subclass, as well as fragments of such antibodies, as long as they have the biological activity described in the present application (see US Patent No. 4,816,567; and Morrison et al., Proc. Natl. Acad. Sci. USA, 81: 6851-6855 (1984)).

[0049] "Fv" is the smallest antibody fragment that contains a complete antigen recognition and binding site. This fragment is a dimer formed by a heavy chain variable domain and a light chain variable domain tightly non-covalently linked. Six hypervariable loops (3 loops each in the light chain and heavy chain) are derived from the folding of these two domains, which provide the antibody with amino acid residues for binding to the antigen and give the antibody specificity for binding to the antigen. However, even a single variable domain (or half of an Fv fragment, which contains only 3 CDRs specific for the antigen) has the ability to recognize and bind to the antigen, although its affinity is lower than that of the complete binding site.

[0050] "Single-chain Fv", also abbreviated as "sFv" or "scFv", is a Fv comprising V linked into a single polypeptide chain. H and V L In some embodiments, the scFv polypeptide further comprises a V H and V LThe connecting polypeptide between the domains allows the scFv to form an ideal structure for antigen binding. For an overview of scFv, see Pluckthun in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Moore eds., Springer-Verlag, New York, pp. 269-315 (1994).

[0051] The term "diabody" is used in V H and V L A small antibody fragment prepared by constructing scFv fragments (see above) with short linkers (e.g., 5 to 10 residues) between the domains, so that the variable domains pair between chains rather than within the chains, producing a bivalent fragment, that is, a fragment with two antigen-binding sites. A bispecific diabody is a heterodimer of two "crossed" scFv fragments, in which the V H and V L The domains are located on different polypeptide chains. Diabodies are fully described in EP 404,097; WO 93 / 11161; Hollinger et al., Proc. Natl. Acad. Sci. USA, 90:6444-6448 (1993).

[0052] The "humanized" form of a non-human (such as rodent) antibody is a chimeric antibody that includes minimal sequences from a non-human antibody. In most cases, a humanized antibody is a human immunoglobulin (receptor antibody) in which the hypervariable region (HVR) residues of the receptor antibody are replaced by residues from a non-human species such as a mouse, rat, rabbit or non-human mammal with an ideal antibody specificity, affinity and performance (donor antibody). In some cases, residues in the framework region of a human immunoglobulin are replaced by corresponding non-human residues. In addition, a humanized antibody may include residues that are not present in either the receptor antibody or the donor antibody. These modifications can further improve the performance of the antibody. Typically, a humanized antibody will include substantially all, at least one, and usually two variable domains, wherein all or substantially all of the hypervariable loops correspond to the hypervariable loops of a non-human immunoglobulin, and all or substantially all of the framework regions are human immunoglobulin sequences. Human antibodies optionally also include at least a portion of an immunoglobulin constant region (Fc), typically a constant region of a human immunoglobulin. For details, see Jones et al., Nature 321: 522-525 (1986); Riechmann et al., Nature 332: 323-329 (1988); and Presta, Curr. Op. Struct. Biol. 2: 593-596 (1992).

[0053] The "percent (%) amino acid sequence identity" or "homology" of the polypeptide and antibody sequences identified herein is defined as the percentage of identical amino acid residues in a candidate sequence and the polypeptide sequence to be compared, when conservative substitutions are considered to be part of the sequence identity. The percentage of amino acid sequence identity can be determined by a variety of alignment methods within the skill of the art, for example, using publicly available computer software such as BLAST, BLAST-2, ALIGN, Megalign (DNASTAR), or MUSCLE software. One skilled in the art can determine appropriate parameters for measuring alignment, including any algorithm required to maximize alignment over the entire length of the compared sequences. However, for the purposes of this article, the percentage of amino acid sequence identity values ​​are generated using the sequence alignment computer program MUSCLE (Edgar, RC, Nucleic Acids Research 32 (5): 1792-1797, 2004; Edgar, RC, BMC Bioinformatics 5 (1): 113, 2004).

[0054] The term "Fc receptor" or "FcR" is used to describe a receptor that binds to the Fc region of an antibody. In some embodiments, the FcR described herein is an FcR that binds to an IgG antibody (a gamma receptor), including receptors of the FcγRI, FcγRII, and FcγRIII subclasses, including allelic variants and alternative splicing forms of these receptors. FcγRII receptors include FcγRIIA ("activating receptor") and FcγRIIB ("inhibiting receptor"), which have similar amino acid sequences and differ primarily in the cytoplasmic domain. The cytoplasmic domain of the activating receptor FcγRIIA contains an immunoreceptor tyrosine-based activation motif (ITAM). The cytoplasmic domain of the inhibitory receptor FcγRIIB contains an immunoreceptor tyrosine-based inhibition motif (ITIM) (see M.in Annu. Rev. Immunol. 15: 203-234 (1997)). The term also includes allotypes, such as the FcγRIIIA allotypes: FcγRIIIA-Phe158, FcγRIIIA-Val158, FcγRIIA-R131 and / or FcγRIIA-H131. FcRs are described in Ravetch and Kinet, Annu. Rev. Immunol 9: 457-92 (1991) and Capel et al., Immunomethods 4: 25-34 (1994); and de Haas et al., J. Lab. Clin. Med. 126: 330-41 (1995). The term FcR in this application encompasses other types of FcRs, including FcRs identified in the future. The term FcR also includes the neonatal receptor FcRn, which is responsible for the transfer of maternal IgGs to the newborn (Guyer et al., J. Immunol. 117:587 (1976) and Kim et al., J. Immunol. 24:249 (1994)).

[0055] The term "FcRn" refers to the neonatal Fc receptor (FcRn). FcRn is structurally similar to the major histocompatibility complex (MHC) and consists of an α chain non-covalently bound to β2 microglobulin. The various functions of the neonatal Fc receptor FcRn are reviewed in Ghetie and Ward (2000) Annu. Rev. Immunol. 18, 739-766. FcRn plays an important role in the passive transport of immunoglobulins IgGs from mothers to newborns and in regulating serum IgG levels. As a rescue receptor, FcRn can bind and transport endocytosed IgG in an intact form within and between cells, and protect them from the default degradation pathway.

[0056] The human IgG heavy chain constant region "CH The "1 domain" generally extends from amino acid 118 to amino acid 215 (EU numbering system).

[0057] The "hinge region" is generally defined as extending from Glu 216 to Pro 230 of human IgG1 (Burton, Molec. Immunol. 22: 161-206 (1985)). By placing the first and last cysteine ​​residues that form inter-heavy chain disulfide bonds in the same position as IgG1, the hinge regions of other IgG isotypes can be aligned with the IgG1 sequence.

[0058] Human IgG Fc region "C H The "2 domain" usually extends from amino acid 231 to amino acid 340. H Domain 2 is unique in that it does not pair closely with another region, but rather is located between the two C H Two N-terminally linked branched sugar chains are inserted between the 2 domains. It is speculated that the sugars may serve as a substitute for domain-domain pairing, helping to maintain C H 2 domain stabilization. Burton, Molec. Immunol. 22: 161-206 (1985).

[0059] “C H The 3" domain includes the C-terminal residues extending from the C H 2 domain (from amino acid 341 to the C-terminus of the antibody sequence, usually amino acid residue 446 or 447 of IgG).

[0060] A "functional Fc fragment" has the "effector functions" possessed by a native Fc region sequence. Exemplary "effector functions" include C1q binding; complement-dependent cytotoxicity (CDC); Fc receptor binding; antibody-dependent cell-mediated cytotoxicity (ADCC); phagocytosis; downregulation of cell surface receptors (such as B cell receptor; BCR), etc. Such effector functions generally require the Fc region to be combined with a binding domain (such as an antibody variable region) and can be evaluated using a variety of experimental methods known in the art.

[0061] An antibody having an IgG Fc variant with "altered" FcR binding affinity or ADCC activity has increased or decreased FcR binding activity and / or ADCC activity compared to the parent polypeptide or a polypeptide comprising a native Fc sequence. An Fc variant exhibiting "enhanced binding" to an FcR has a higher binding affinity (e.g., lower apparent Kd or ICd) to at least one FcR compared to the parent polypeptide or a polypeptide comprising a native IgG Fc sequence. 50In some embodiments, the binding capacity is enhanced by 3-fold, such as 5, 10, 25, 50, 60, 100, 150, 200, or even up to 500-fold, or the binding capacity is increased by 25% to 1000% compared to the parent polypeptide. An Fc variant that exhibits "reduced binding" to an FcR has a lower affinity (e.g., a higher apparent Kd or ICd) for at least one FcR compared to the parent polypeptide. 50 Compared with the parent polypeptide, its binding capacity is reduced by 40% or more.

[0062] "Antibody-dependent cell-mediated cytotoxicity" or "ADCC" is a form of cytotoxicity that refers to the binding of secreted Ig to Fc receptors (FcRs) present on certain cytotoxic cells (e.g., natural killer cells (NK), neutrophils, and macrophages), enabling these cytotoxic effector cells to specifically bind to target cells bearing antigens and subsequently kill the target cells using cytotoxins. Antibodies "arm" the cytotoxic cells and are required for this killing. Of the major cell types that mediate ADCC, NK cells express only FcγRIII, while monocytes express FcγRI, FcγRII, and FcγRIII. The expression of FcRs on hematopoietic cells is summarized in Table 3 on page 464 of Ravetch and Kinet, Annu. Rev. Immunol 9:457-92 (1991). To assess the ADCC activity of a target molecule, an in vitro ADCC assay can be performed, as described in U.S. Pat. Nos. 5,500,362 or 5,821,337. Effector cells suitable for such experiments include peripheral blood mononuclear cells (PBMC) and natural killer cells (NK). Alternatively, or in addition, ADCC activity of the target molecule can also be assessed in vivo, for example, as described in an animal model disclosed in Clynes et al. PNAS (USA) 95: 652-656 (1998).

[0063] The polypeptide comprising the Fc region variant exhibits "enhanced ADCC activity" or can more effectively mediate the ADCC effect in the presence of human effector cells compared to the polypeptide comprising the wild-type IgG Fc polypeptide or the parent polypeptide. The polypeptide comprising the Fc region variant can more effectively mediate ADCC in vitro or in vivo when the number of polypeptides comprising the wild-type IgG Fc polypeptide (or the parent polypeptide) is substantially the same during the experiment. Such variants are generally identified using any in vitro ADCC experimental method known in the art, such as an experiment or method for identifying ADCC activity, such as in an animal model, etc. In some embodiments, such variants mediate ADCC with an efficiency of 5 to 100 times, such as 25 to 50 times, compared to the wild-type Fc (or the parent polypeptide).

[0064] "Complement-dependent cytotoxicity" or "CDC" refers to the lysis of target cells in the presence of complement. 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 structural subclass) that binds to a cognate antigen. To assess complement activation, a CDC assay, such as that described in Gazzano-Santoro et al., J. Immunol. Methods 202:163 (1996), can be performed. Polypeptide variants having altered Fc region amino acid sequences and increased or decreased C1q binding ability are described in U.S. Patent No. 6,194,551B1 and WO99 / 51642. The contents of these patent publications are expressly incorporated herein by reference. See also Idusogie et al. J. Immunol. 164:4178-4184 (2000).

[0065] Unless otherwise specified, a "nucleotide sequence encoding an amino acid sequence" includes all nucleotide sequences that are degenerate forms of each other and encode the same amino acid sequence. A nucleotide sequence encoding a protein or RNA may also include introns, for example, a nucleotide sequence encoding a protein contains introns in some forms.

[0066] The term "operably linked" refers to a functional connection between a regulatory sequence and a heterologous nucleotide sequence, thereby allowing the latter to be expressed. For example, a first nucleotide sequence is operably linked to a second nucleotide sequence when the first nucleotide sequence is in a functional relationship with the second nucleotide sequence. For example, if a promoter affects the transcription or expression of a coding sequence, the promoter is operably linked to a coding sequence. Generally, operably linked DNA sequences are contiguous and, if necessary, two protein coding regions can be linked in the same reading frame.

[0067] "Homologous" refers to the sequence similarity or sequence identity between two polypeptides or between two nucleic acid molecules. If the same position of two compared sequences is the same base or amino acid monomer subunit, for example, the same position of two DNA molecules is adenine, then the two DNA molecules are homologous at that position. The homology percentage between two sequences refers to the ratio of the number of matching or homologous positions shared by the two sequences to the total number of positions multiplied by 100. For example, if 6 out of 10 positions in two sequences are matched or homologous, the homology of the two sequences is 60%. For example, the DNA sequences ATTGCC and TATGGC have 50% homology. Generally speaking, when aligning two sequences, the comparison is performed with the goal of obtaining maximum homology.

[0068] An "effective amount" of an anti-MASP3 antibody or composition disclosed herein refers to an amount sufficient to achieve a specific purpose. An "effective amount" can be determined empirically and by known methods relevant to the stated purpose.

[0069] The term "therapeutically effective amount" refers to an amount of an anti-MASP3 antibody or composition thereof disclosed herein that is effective in treating a disease or symptom in an individual, that is, an amount sufficient to reduce or improve the severity and / or duration of a disease or one or more symptoms thereof; prevent the development of a disease, cause regression of symptoms, prevent the recurrence, development, onset or progression of one or more symptoms associated with a disease, detect a disease, or enhance / improve the preventive or therapeutic effect of another therapy (e.g., a prophylactic or therapeutic agent).

[0070] As used herein, "pharmaceutically acceptable" or "pharmacologically compatible" refers to materials that are free of biological activity or other undesirable properties, such as materials that can be added to a pharmaceutical composition administered to a patient without causing significant adverse biological reactions, or that do not interact in a harmful manner with any other components contained in the composition. Pharmaceutically acceptable carriers or excipients preferably meet the required standards for toxicology or manufacturing testing and / or are included in the inactive ingredient guide compiled by the U.S. Food and Drug Administration.

[0071] The embodiments of the present application described herein should be understood to include "consisting of" and / or "consisting essentially of" embodiments.

[0072] Reference herein to "about" for a value or parameter includes (and describes) variations for the value or parameter itself. For example, a description involving "about X" includes a description of "X".

[0073] As used herein, reference to "not" a value or parameter generally indicates and describes "other than" a value or parameter. For example, the method cannot be used to treat type X cancer, which means that the method is generally used to treat other types of cancer except type X cancer.

[0074] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0075] Anti-MASP3 Antibodies

[0076] In one aspect, the present application provides anti-MASP3 antibodies that specifically bind to human, monkey and / or mouse MASP3. The anti-MASP3 antibodies include, but are not limited to, humanized antibodies, chimeric antibodies, mouse antibodies, human antibodies, and antibody molecules comprising heavy chain and / or light chain CDRs as described herein. In one aspect, the present application provides isolated antibodies that bind to MASP3. Contemplated anti-MASP3 antibodies include, for example, full-length anti-MASP3 antibodies (such as full-length IgG1 or IgG4), anti-MASP3 single-chain antibodies, anti-MASP3 Fc fusion proteins, multispecific (such as bispecific) anti-MASP3 antibodies, anti-MASP3 immunoconjugates, and the like. In some embodiments, the anti-MASP3 antibody is a full-length antibody (such as full-length IgG1 or IgG4) or an antigen-binding fragment thereof that specifically binds to MASP3. In some embodiments, the anti-MASP3 antibody is Fab, Fab', F(ab)'2, Fab'-SH, single-chain Fv (scFv), Fv fragment, dAb, Fd, nanobody, diabody or linear antibody. In some embodiments, an antibody that specifically binds to MASP3 means that the antibody has an affinity for binding to MASP3 that is at least 10 times greater than the affinity for binding to a non-target (including, for example, 10, 10 2 , 10 3 , 10 4 , 10 5 , 10 6 , or 10 7 In some embodiments, non-target refers to an antigen that is not MASP3. Binding affinity can be determined by methods known in the art, such as ELISA, fluorescence activated cell sorting (FACS) analysis or radioimmunoprecipitation analysis (RIA). Kd values ​​can be determined by methods known in the art, such as surface plasmon resonance (SPR) technology or biolayer interferometry (BLI).

[0077] Although anti-MASP3 antibodies comprising human sequences (e.g., human heavy and light chain variable domains comprising human CDR sequences) are discussed extensively herein, non-human anti-MASP3 antibodies are also contemplated. In some embodiments, non-human anti-MASP3 antibodies include human CDR sequences of anti-MASP3 antibodies described herein and non-human framework sequences. In some embodiments, non-human framework sequences include any sequence used to generate heavy and / or light chain variable domains using one or more human CDR sequences as described herein, including, for example, mammals, such as mice, rats, rabbits, pigs, cattle (e.g., cows, bulls, buffaloes), deer, sheep, goats, chickens, cats, dogs, ferrets, primates (e.g., small apes, macaques), etc. In some embodiments, non-human anti-MASP3 antibodies include anti-MASP3 antibodies generated by grafting one or more human CDR sequences described herein into non-human framework sequences (e.g., mouse or chicken framework sequences).

[0078] The complete amino acid sequence of an exemplary human MASP3 comprises or consists of the amino acid sequence shown in SEQ ID NO:34.

[0079] In some embodiments, the anti-MASP3 antibodies described herein specifically recognize an epitope in human MASP3. In some embodiments, the anti-MASP3 antibodies cross-react with MASP3 of species other than human. In some embodiments, the anti-MASP3 antibodies are completely specific for human MASP3 and do not cross-react with other non-human species.

[0080] In some embodiments, the anti-MASP3 antibody cross-reacts with at least one allelic variant of a MASP3 protein (or a fragment thereof). In some embodiments, the allelic variant has up to 30 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, or 30) amino acid substitutions (e.g., conservative substitutions) compared to a naturally occurring MASP3 protein (or a fragment thereof). In some embodiments, the anti-MASP3 antibody does not cross-react with any allelic variant of a MASP3 protein (or a fragment thereof).

[0081] In some embodiments, the anti-MASP3 antibody cross-reacts with at least one interspecies variant of the MASP3 protein. In some embodiments, for example, the MASP3 protein (or a fragment thereof) is human MASP3, and the interspecies variant of the MASP3 protein (or a fragment thereof) is a variant in cynomolgus monkey. In some embodiments, the anti-MASP3 antibody does not cross-react with any interspecies variant of the MASP3 protein.

[0082] In some embodiments, as any anti-MASP3 antibody described herein, the anti-MASP3 antibody comprises an antibody heavy chain constant region and an antibody light chain constant region. In some embodiments, the anti-MASP3 antibody comprises an IgG1-type heavy chain constant region. In some embodiments, the anti-MASP3 antibody comprises an IgG2-type heavy chain constant region. In some embodiments, the anti-MASP3 antibody comprises an IgG3-type heavy chain constant region. In some embodiments, the anti-MASP3 antibody comprises an IgG4-type heavy chain constant region. In some embodiments, the heavy chain constant region comprises (including consisting of or consisting essentially of) the amino acid sequence SEQ ID NO: 30. In some embodiments, the heavy chain constant region comprises (including consisting of or consisting essentially of) the amino acid sequence SEQ ID NO: 31. In some embodiments, the anti-MASP3 antibody comprises a kappa light chain constant region. In some embodiments, the light chain constant region comprises (including consisting of or consisting essentially of) the amino acid sequence SEQ ID NO: 32. In some embodiments, the anti-MASP3 antibody comprises a lambda light chain constant region. In some embodiments, the light chain constant region comprises (including consisting of or consisting essentially of) the amino acid sequence SEQ ID NO: 33. In some embodiments, the anti-MASP3 antibody comprises an antibody heavy chain variable domain and an antibody light chain variable domain.

[0083] In some embodiments, the anti-MASP3 antibody comprises V H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, or the V H A variant of V comprising substitutions of up to about 5 amino acids in its HC-CDRs; and V L , the V L comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 13, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 16, LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 19, or the V L A variant comprising substitutions of up to about 5 amino acids in the LC-CDRs.

[0084] In some embodiments, the anti-MASP3 antibody comprises V H , the V Hcomprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:13, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:16, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:19.

[0085] In some embodiments, the anti-MASP3 antibody comprises V H , which comprises V as shown in the amino acid sequence SEQ ID NO:22 H HC-CDR1, HC-CDR2 and HC-CDR3; and V L , which comprises V as shown in the amino acid sequence SEQ ID NO:26 L Contains LC-CDR1, LC-CDR2 and LC-CDR3.

[0086] In some embodiments, the anti-MASP3 antibody comprises: H , the V H comprising the amino acid sequence of SEQ ID NO:22 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity to the amino acid sequence of SEQ ID NO:22; and V L , the V L The invention relates to an anti-MASP3 antibody comprising an amino acid sequence of SEQ ID NO: 26 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity to the amino acid sequence of SEQ ID NO: 26. In some embodiments, the anti-MASP3 antibody comprises V H , the V H Comprising the amino acid sequence SEQ ID NO: 22, and V L , the V L Comprising the amino acid sequence SEQ ID NO:26.

[0087] In some embodiments, the anti-MASP3 antibody comprises V H , the V Hcomprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 2, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 6, HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 10, or the V H A variant of V comprising substitutions of up to about 5 amino acids in its HC-CDRs; and V L , the V L comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 14, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 17, LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 20, or the V L A variant comprising substitutions of up to about 5 amino acids in the LC-CDRs.

[0088] In some embodiments, the anti-MASP3 antibody comprises V H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 2, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 6, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 10; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:14, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:17, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:20.

[0089] In some embodiments, the anti-MASP3 antibody comprises V H , which comprises V as shown in the amino acid sequence SEQ ID NO:23 H HC-CDR1, HC-CDR2 and HC-CDR3; and V L , which comprises V as shown in the amino acid sequence SEQ ID NO: 27 L Contains LC-CDR1, LC-CDR2 and LC-CDR3.

[0090] In some embodiments, the anti-MASP3 antibody comprises: H , the V H comprising the amino acid sequence of SEQ ID NO:23 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity to the amino acid sequence of SEQ ID NO:23; and V L , the VL The invention relates to an anti-MASP3 antibody comprising an amino acid sequence of SEQ ID NO: 27 or a variant thereof having at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity to the amino acid sequence of SEQ ID NO: 27. In some embodiments, the anti-MASP3 antibody comprises V H , the V H Comprising the amino acid sequence SEQ ID NO: 23, and V L , the V L Comprising the amino acid sequence SEQ ID NO:27.

[0091] In some embodiments, the anti-MASP3 antibody comprises V H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 3, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 7, HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 11, or the V H A variant of V comprising substitutions of up to about 5 amino acids in its HC-CDRs; and V L , the V L comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 15, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 18, LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 21, or the V L A variant comprising substitutions of up to about 5 amino acids in the LC-CDRs.

[0092] In some embodiments, the anti-MASP3 antibody comprises V H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 3, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 7, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:15, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:18, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:21.

[0093] In some embodiments, the anti-MASP3 antibody comprises V H , which comprises V as shown in the amino acid sequence SEQ ID NO:24 HHC-CDR1, HC-CDR2 and HC-CDR3; and V L , which comprises V as shown in the amino acid sequence SEQ ID NO:28 L Contains LC-CDR1, LC-CDR2 and LC-CDR3.

[0094] In some embodiments, the anti-MASP3 antibody comprises: H , the V H comprising the amino acid sequence of SEQ ID NO: 24 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity to the amino acid sequence of SEQ ID NO: 24; and V L , the V L The invention relates to an anti-MASP3 antibody comprising an amino acid sequence of SEQ ID NO: 28 or a variant thereof having at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity to the amino acid sequence of SEQ ID NO: 28. In some embodiments, the anti-MASP3 antibody comprises V H , the V H Comprising the amino acid sequence SEQ ID NO: 24, and V L , the V L Comprising the amino acid sequence SEQ ID NO:28.

[0095] In some embodiments, the anti-MASP3 antibody comprises V H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12, or the V H A variant of V comprising substitutions of up to about 5 amino acids in its HC-CDRs; and V L , the V L comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 15, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 18, LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 21, or the V L A variant comprising substitutions of up to about 5 amino acids in the LC-CDRs.

[0096] In some embodiments, the anti-MASP3 antibody comprises V H , the V Hcomprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:15, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:18, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:21.

[0097] In some embodiments, the anti-MASP3 antibody comprises V H , which comprises V as shown in the amino acid sequence SEQ ID NO:25 H HC-CDR1, HC-CDR2 and HC-CDR3; and V L , which comprises V as shown in the amino acid sequence SEQ ID NO:29 L Contains LC-CDR1, LC-CDR2 and LC-CDR3.

[0098] In some embodiments, the anti-MASP3 antibody comprises: H , the V H comprising the amino acid sequence of SEQ ID NO: 25 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity to the amino acid sequence of SEQ ID NO: 25; and V L , the V L The invention relates to an anti-MASP3 antibody comprising an amino acid sequence of SEQ ID NO: 29 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity to the amino acid sequence of SEQ ID NO: 29. In some embodiments, the anti-MASP3 antibody comprises V H , the V H Comprising the amino acid sequence SEQ ID NO: 25, and V L , the V L Comprising the amino acid sequence SEQ ID NO:29.

[0099] In some embodiments, the above-mentioned amino acid substitutions are limited to the "exemplary substitutions" shown in Table 4 herein. In some embodiments, the amino acid substitutions are limited to the "preferred substitutions" shown in Table 4 herein.

[0100] In some embodiments, functional epitopes can be resolved by combinatorial alanine scanning. In this process, combinatorial alanine scanning technology can be used to identify amino acids in the MASP3 protein that are necessary for interaction with the anti-MASP3 antibody. In some embodiments, the epitope is conformational and the crystal structure of the anti-MASP3 antibody bound to the MASP3 protein can be used to identify the epitope.

[0101] In some embodiments, the present application provides antibodies that compete with any of the anti-MASP3 antibodies described herein for binding to MASP3. In some embodiments, antibodies that can compete with any of the anti-MASP3 antibodies described herein for binding to an epitope on MASP3 are provided. In some embodiments, anti-MASP3 antibodies are provided that are combined with a V H and V L The anti-MASP3 antibody molecules bind to the same epitope, wherein the V H comprising an amino acid sequence as shown in any one of SEQ ID NOs: 22-25, and said V L comprising an amino acid sequence as shown in any one of SEQ ID NOs: 26-29. In some embodiments, an anti-MASP3 antibody is provided, which is combined with a V H and V L The anti-MASP3 antibody competitively binds to MASP3, wherein the V H comprising an amino acid sequence as shown in any one of SEQ ID NOs: 22-25, and said V L It comprises the amino acid sequence shown in any one of SEQ ID NOs: 26-29.

[0102] In some embodiments, competition assays can be used to identify monoclonal antibodies that compete with the anti-MASP3 antibodies described herein for binding to MASP3. Competition assays can determine whether two antibodies bind to the same epitope by recognizing the same or spatially overlapping epitopes or by competitively inhibiting the binding of another antibody to the antigen. In certain embodiments, such competing antibodies bind to the same epitope as the antibodies described herein. Some exemplary competition assays include, but are not limited to, routine assays as described in Harlow and Lane (1988) Antibodies: A Laboratory Manual ch. 14 (Cold Spring Harbor Laboratory, Cold Spring Harbor, NY). Detailed exemplary methods for resolving epitopes bound by antibodies are described in Morris (1996) "Epitope Mapping Protocols," in Methods in Molecular Biology vol. 66 (Humana Press, Totowa, NJ). In some embodiments, if each antibody blocks 50% or more of the binding of the other antibody, it is said to bind to the same epitope. In some embodiments, the antibodies that compete with the anti-MASP3 antibodies described herein are chimeric antibodies, humanized antibodies, or fully human antibodies.

[0103] Exemplary anti-MASP3 antibody sequences are shown in Tables 2 and 3, wherein CDR numbering is performed according to the Kabat definition. Those skilled in the art will recognize that there are a variety of known algorithms for predicting the position of CDRs and defining antibody light and heavy chain variable regions. H and / or V L Sequences, but based on prediction algorithms other than the antibodies exemplified in the table below are also within the scope of the present application.

[0104] Table 2 Exemplary anti-MASP3 antibody CDR sequences

[0105]

[0106]

[0107] Table 3 Exemplary sequences

[0108]

[0109]

[0110] Full-length anti-MASP3 antibody

[0111] In some embodiments, the anti-MASP3 antibody is a full-length anti-MASP3 antibody. In some embodiments, the full-length anti-MASP3 antibody is IgA, IgD, IgE, IgG, or IgM. In some embodiments, the full-length anti-MASP3 antibody comprises an IgG constant region, such as a constant region of IgG1, IgG2, IgG3, IgG4, or a variant thereof. In some embodiments, the full-length anti-MASP3 antibody comprises a lambda light chain constant region. In some embodiments, the full-length anti-MASP3 antibody comprises a kappa light chain constant region. In some embodiments, the full-length anti-MASP3 antibody is a full-length human anti-MASP3 antibody. In some embodiments, the full-length anti-MASP3 antibody comprises a mouse immunoglobulin Fc sequence. In some embodiments, the full-length anti-MASP3 antibody comprises an altered or otherwise modified Fc sequence such that it has enhanced effector functions of antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC).

[0112] Thus, for example, in some embodiments, a full length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody specifically binds to MASP3. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0113] In some embodiments, a full length anti-MASP3 antibody comprising an IgG2 constant region is provided, wherein the anti-MASP3 antibody specifically binds to MASP3. In some embodiments, the IgG2 is human IgG2. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0114] In some embodiments, a full length anti-MASP3 antibody comprising an IgG3 constant region is provided, wherein the anti-MASP3 antibody specifically binds to MASP3. In some embodiments, the IgG3 is human IgG3. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0115] In some embodiments, a full length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody specifically binds to MASP3. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0116] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain, the heavy chain variable domain comprising: HC-CDR1 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 1-4 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; HC-CDR2 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 5-8 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; and HC-CDR3 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 9-12 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; and b) a light chain variable domain, the light chain variable domain comprising: LC-CDR1 comprising SEQ ID NOs: NOs: 13-15 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids, LC-CDR2, which comprises an amino acid sequence as shown in any one of SEQ ID NOs: 16-18 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids; and LC-CDR3, which comprises an amino acid sequence as shown in any one of SEQ ID NOs: 19-21 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0117] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG2 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain, the heavy chain variable domain comprising: HC-CDR1 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 1-4 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; HC-CDR2 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 5-8 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; and HC-CDR3 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 9-12 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; and b) a light chain variable domain, the light chain variable domain comprising: LC-CDR1 comprising SEQ ID NOs: NOs: 13-15 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids; LC-CDR2, which comprises an amino acid sequence as shown in any one of SEQ ID NOs: 16-18 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids; and LC-CDR3, which comprises an amino acid sequence as shown in any one of SEQ ID NOs: 19-21 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids. In some embodiments, the IgG2 is a human IgG2. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33.

[0118] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG3 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain, the heavy chain variable domain comprising: HC-CDR1 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 1-4 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids, HC-CDR2 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 5-8 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; and HC-CDR3 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 9-12 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; and b) a light chain variable domain, the light chain variable domain comprising: LC-CDR1 comprising SEQ ID NOs: NOs: 13-15 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids; LC-CDR2, which comprises an amino acid sequence as shown in any one of SEQ ID NOs: 16-18 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids; and LC-CDR3, which comprises an amino acid sequence as shown in any one of SEQ ID NOs: 19-21 or a variant thereof, wherein the variant comprises a substitution of up to about 3 (e.g., 1, 2, or 3) amino acids. In some embodiments, the IgG3 is a human IgG3. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0119] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain, the heavy chain variable domain comprising: HC-CDR1 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 1-4 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; HC-CDR2 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 5-8 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; and HC-CDR3 comprising an amino acid sequence as shown in any one of SEQ ID NOs: 9-12 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids; and b) a light chain variable domain, the light chain variable domain comprising: LC-CDR1 comprising SEQ ID NOs: NOs: 13-15 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids, LC-CDR2, which comprises an amino acid sequence as shown in any one of SEQ ID NOs: 16-18 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids, and LC-CDR3, which comprises an amino acid sequence as shown in any one of SEQ ID NOs: 19-21 or a variant thereof, the variant comprising a substitution of up to about 3 (e.g., 1, 2 or 3) amino acids. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0120] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain, the heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of any one of SEQ ID NOs: 1-4, HC-CDR2 comprising the amino acid sequence of any one of SEQ ID NOs: 5-8, and HC-CDR3 comprising the amino acid sequence of any one of SEQ ID NOs: 9-12, or a variant of the heavy chain variable domain comprising up to about 5 (e.g., 1, 2, 3, 4, or 5) amino acid substitutions in the HC-CDR sequence; and b) a light chain variable domain, the light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of any one of SEQ ID NOs: 13-15, LC-CDR2 comprising the amino acid sequence of any one of SEQ ID NOs: 16-18, and LC-CDR3 comprising the amino acid sequence of SEQ ID NOs: NOs: The amino acid sequence shown in any one of 19-21, or a variant of the light chain variable domain, comprising a substitution of up to about 5 (e.g., 1, 2, 3, 4, or 5) amino acids in its LC-CDR sequence. In some embodiments, the IgG1 is human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:33.

[0121] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of any one of SEQ ID NOs: 1-4, HC-CDR2 comprising the amino acid sequence of any one of SEQ ID NOs: 5-8, and HC-CDR3 comprising the amino acid sequence of any one of SEQ ID NOs: 9-12, or a variant of the heavy chain variable domain comprising up to about 5 (e.g., 1, 2, 3, 4, or 5) amino acid substitutions in the HC-CDR sequence; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of any one of SEQ ID NOs: 13-15, LC-CDR2 comprising the amino acid sequence of any one of SEQ ID NOs: 16-18, and LC-CDR3 comprising the amino acid sequence of SEQ ID NOs: 17-19. NOs: 19-21, or a variant of the light chain variable domain, wherein the LC-CDR sequence comprises a substitution of up to about 5 (e.g., 1, 2, 3, 4, or 5) amino acids. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33.

[0122] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of any one of SEQ ID NOs: 1-4, HC-CDR2 comprising the amino acid sequence of any one of SEQ ID NOs: 5-8, and HC-CDR3 comprising the amino acid sequence of any one of SEQ ID NOs: 9-12; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of any one of SEQ ID NOs: 13-15, LC-CDR2 comprising the amino acid sequence of any one of SEQ ID NOs: 16-18, and LC-CDR3 comprising the amino acid sequence of any one of SEQ ID NOs: 19-21. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0123] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of any one of SEQ ID NOs: 1-4, HC-CDR2 comprising the amino acid sequence of any one of SEQ ID NOs: 5-8, and HC-CDR3 comprising the amino acid sequence of any one of SEQ ID NOs: 9-12; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of any one of SEQ ID NOs: 13-15, LC-CDR2 comprising the amino acid sequence of any one of SEQ ID NOs: 16-18, and LC-CDR3 comprising the amino acid sequence of any one of SEQ ID NOs: 19-21. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0124] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 13, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 16, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 19. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0125] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO:2, HC-CDR2 comprising the amino acid sequence of SEQ ID NO:6, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO:10; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO:14, LC-CDR2 comprising the amino acid sequence of SEQ ID NO:17, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO:20. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0126] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO:3, HC-CDR2 comprising the amino acid sequence of SEQ ID NO:7, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO:11; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO:15, LC-CDR2 comprising the amino acid sequence of SEQ ID NO:18, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO:21. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0127] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO:4, HC-CDR2 comprising the amino acid sequence of SEQ ID NO:8, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO:12; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO:15, LC-CDR2 comprising the amino acid sequence of SEQ ID NO:18, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO:21. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0128] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 13, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 16, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 19. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0129] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO:2, HC-CDR2 comprising the amino acid sequence of SEQ ID NO:6, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO:10; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO:14, LC-CDR2 comprising the amino acid sequence of SEQ ID NO:17, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO:20. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0130] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO:3, HC-CDR2 comprising the amino acid sequence of SEQ ID NO:7, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO:11; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO:15, LC-CDR2 comprising the amino acid sequence of SEQ ID NO:18, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO:21. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0131] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: a) a heavy chain variable domain comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO:4, HC-CDR2 comprising the amino acid sequence of SEQ ID NO:8, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO:12; and b) a light chain variable domain comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO:15, LC-CDR2 comprising the amino acid sequence of SEQ ID NO:18, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO:21. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0132] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a heavy chain variable domain (V H ), the V H The invention comprises an amino acid sequence as shown in any one of SEQ ID NOs: 22-25 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity with the amino acid sequence as shown in any one of SEQ ID NOs: 22-25; and a light chain variable domain (V L ), the V LComprising an amino acid sequence as shown in any one of SEQ ID NOs: 26-29 or a variant thereof, the variant having at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity with the amino acid sequence as shown in any one of SEQ ID NOs: 26-29. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33.

[0133] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG2 constant region is provided, wherein the anti-MASP3 antibody comprises: a heavy chain variable domain (V H ), the V H The invention comprises an amino acid sequence as shown in any one of SEQ ID NOs: 22-25 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity with the amino acid sequence as shown in any one of SEQ ID NOs: 22-25; and a light chain variable domain (V L ), the V L The invention relates to an IgG2 polypeptide comprising an amino acid sequence as set forth in any one of SEQ ID NOs: 26-29 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity with the amino acid sequence as set forth in any one of SEQ ID NOs: 26-29. In some embodiments, the IgG2 is a human IgG2. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0134] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG3 constant region is provided, wherein the anti-MASP3 antibody comprises: a heavy chain variable domain (V H ), the V HThe invention comprises an amino acid sequence as shown in any one of SEQ ID NOs: 22-25 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity with the amino acid sequence as shown in any one of SEQ ID NOs: 22-25; and a light chain variable domain (V L ), the V L The invention relates to an IgG3 polypeptide comprising an amino acid sequence as set forth in any one of SEQ ID NOs: 26-29 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity with the amino acid sequence as set forth in any one of SEQ ID NOs: 26-29. In some embodiments, the IgG3 is a human IgG3. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0135] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: a heavy chain variable domain (V H ), the V H The invention comprises an amino acid sequence as shown in any one of SEQ ID NOs: 22-25 or a variant thereof, wherein the variant has at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity with the amino acid sequence as shown in any one of SEQ ID NOs: 22-25; and a light chain variable domain (V L ), the V LComprising an amino acid sequence as shown in any one of SEQ ID NOs: 26-29 or a variant thereof, the variant having at least about 80% (e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%) sequence identity with the amino acid sequence as shown in any one of SEQ ID NOs: 26-29. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO: 33.

[0136] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: a heavy chain variable domain (V H ), the V H Comprising the amino acid sequence shown in any one of SEQ ID NOs: 22-25, and a light chain variable domain (V L ), the V L In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0137] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: a heavy chain variable domain (V H ), the V HComprising the amino acid sequence shown in any one of SEQ ID NOs: 22-25, and a light chain variable domain (V L ), the V L In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO: 33.

[0138] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: V H , comprising the amino acid sequence of SEQ ID NO: 22 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 22; and V L , which comprises the amino acid sequence of SEQ ID NO:26 or a variant thereof, the variant having at least about 80% sequence identity with the amino acid sequence of SEQ ID NO:26. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0139] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: V H, comprising the amino acid sequence of SEQ ID NO: 23 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 23; and V L , which comprises the amino acid sequence of SEQ ID NO:27 or a variant thereof, the variant having at least about 80% sequence identity with the amino acid sequence of SEQ ID NO:27. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0140] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: V H , comprising the amino acid sequence of SEQ ID NO: 24 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 24; and V L , which comprises the amino acid sequence of SEQ ID NO:28 or a variant thereof, the variant having at least about 80% sequence identity with the amino acid sequence of SEQ ID NO:28. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0141] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG1 constant region is provided, wherein the anti-MASP3 antibody comprises: V H, comprising the amino acid sequence of SEQ ID NO: 25 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 25; and V L , which comprises the amino acid sequence of SEQ ID NO:29 or a variant thereof, the variant having at least about 80% sequence identity with the amino acid sequence of SEQ ID NO:29. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:30 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0142] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: V H , comprising the amino acid sequence of SEQ ID NO: 22 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 22; and V L , which comprises the amino acid sequence of SEQ ID NO:26 or a variant thereof, the variant having at least about 80% sequence identity with the amino acid sequence of SEQ ID NO:26. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0143] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: V H, comprising the amino acid sequence of SEQ ID NO: 23 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 23; and V L , which comprises the amino acid sequence of SEQ ID NO:27 or a variant thereof, the variant having at least about 80% sequence identity with the amino acid sequence of SEQ ID NO:27. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0144] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: V H , comprising the amino acid sequence of SEQ ID NO: 24 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 24; and V L , which comprises the amino acid sequence of SEQ ID NO:28 or a variant thereof, the variant having at least about 80% sequence identity with the amino acid sequence of SEQ ID NO:28. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0145] In some embodiments, a full-length anti-MASP3 antibody comprising an IgG4 constant region is provided, wherein the anti-MASP3 antibody comprises: V H, comprising the amino acid sequence of SEQ ID NO: 25 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 25; and V L , which comprises the amino acid sequence of SEQ ID NO:29 or a variant thereof, the variant having at least about 80% sequence identity with the amino acid sequence of SEQ ID NO:29. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:32. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:31 and the light chain constant region comprises or consists of the amino acid sequence of SEQ ID NO:33.

[0146] Binding affinity

[0147] Binding affinity is expressed as Kd, Koff, Kon or Ka. As used herein, the term Koff refers to the rate constant for the dissociation of an antibody from an antigen / antibody complex, measured by a kinetic selection apparatus. The term Kon refers to the association rate constant for the binding of an antibody to an antigen to form an antigen / antibody complex. The equilibrium dissociation constant Kd used herein refers to the dissociation constant for a specific antibody-antigen interaction, and refers to the antigen concentration required in a solution of antibody molecules for the antigen to occupy half of all antibody binding sites and to reach equilibrium, which is equal to Koff / Kon. The determination of Kd assumes that all binding molecules are in solution. In the case where the antibody is attached to the cell wall, such as in a yeast expression system, the corresponding equilibrium dissociation rate constant is expressed as EC 50 It is expressed as , which is a good approximation of Kd. The affinity binding constant Ka is the reciprocal of the dissociation constant Kd.

[0148] The dissociation constant (Kd) can be used as an indicator of the affinity of the reactive antibody moiety for the antigen. For example, simple analysis can be performed by the Scatchard method using antibodies labeled with various markers and a Biacore instrument (manufactured by Amersham Biosciences) to analyze the interaction between biomolecules by surface plasmon resonance according to the user manual or the accompanying kit. The Kd values ​​obtained using these methods are expressed in units of M. An antibody that specifically binds to a target may have, for example, ≤10 -7 M, ≤10 -8 M, ≤10-9 M, ≤10 -10 M, ≤10 -11 M, ≤10 -12 M or ≤10 -13 Kd value of M.

[0149] The binding specificity of the antibody can be experimentally determined by methods known in the art, including, but not limited to, Western blots, ELISA-, RIA-, ECL-, IRMA-, EIA-, BIAcore assays, and peptide scanning.

[0150] In some embodiments, the anti-MASP3 antibody specifically binds to the MASP3 target with a Kd value of 10 -7 M to 10 -13 M (e.g. 10 -7 M to 10 -13 M, 10 -8 M to 10 -13 M, 10 -9 M to 10 -13 M or 10 -10 M to 10 -12 Thus, in some embodiments, the Kd value of the binding between the anti-MASP3 antibody and MASP3 is 10 -7 M to 10 -13 M, 1×10 -7 M to 5×10 -13 M, 10 -7 M to 10 -12 M, 10 -7 M to 10 -11 M, 10 -7 M to 10 -10 M, 10 -7 M to 10 -9 M, 10 -8 M to 10 -13 M, 1×10 -8 M to 5×10 -13 M, 10 -8 M to 10 - 12 M, 10 -8 M to 10 -11 M, 10 -8 M to 10 -10 M, 10 -8 M to 10 -9 M, 5×10 -9 M to 1×10 -13 M, 5×10 -9 M to 1×10 -12 M, 5×10 -9M to 1×10 -11 M, 5×10 -9 M to 1×10 -10 M, 10 -9 M to 10 -13 M, 10 -9 M to 10 -12 M, 10 -9 M to 10 -11 M, 10 -9 M to 10 -10 M, 5×10 -10 M to 1×10 -13 M, 5×10 -10 M to 1×10 -12 M, 5×10 -10 M to 1×10 -11 M, 10 -10 M to 10 - 13 M, 1×10 -10 M to 5×10 -13 M, 1×10 -10 M to 1×10 -12 M, 1×10 -10 M to 5×10 -12 M, 1×10 -10 M to 1×10 - 11 M, 10 -11 M to 10 -13 M, 1×10 -11 M to 5×10 -13 M, 10 -11 M to 10 -12 M, 10 -12 M to 10 -13 In some embodiments, the Kd value of the binding between the anti-MASP3 antibody and MASP3 is 10 -7 M to 10 -13 M.

[0151] In some embodiments, the Kd value of the anti-MASP3 antibody binding to the non-target is higher than the Kd value of the anti-MASP3 antibody binding to the target, and in some embodiments cited herein, the binding affinity of the anti-MASP3 antibody to the target (e.g., MASP3) is higher than the binding affinity of the anti-MASP3 antibody to the non-target. In some embodiments, the non-target is an antigen other than MASP3. In some embodiments, the Kd value of the anti-MASP3 antibody (directed to MASP3) binding to the non-MASP3 target differs by at least 10 times, such as 10-100 times, 100-1000 times, 10 3 -10 4 times, 10 4-10 5 times, 10 5 -10 6 times, 10 6 -10 7 times, 10 7 -10 8 times, 10 8 -10 9 times, 10 9 -10 10 times, 10 10 -10 11 times, 10 11 -10 12 times.

[0152] In some embodiments, the anti-MASP3 antibody has a Kd value of 10 for binding to a non-target -1 M to 10 -6 M (e.g. 10 - 1 M to 10 -6 M, 10 -1 M to 10 -5 M, 10 -2 M to 10 -4 In some embodiments, the non-target is an antigen other than MASP3. Thus, in some embodiments, the Kd value of the binding between the anti-MASP3 antibody and the non-MASP3 target is 10 -1 M to 10 -6 M, 1×10 -1 M to 5×10 -6 M, 10 -1 M to 10 -5 M, 1×10 -1 M to 5×10 -5 M, 10 -1 M to 10 -4 M, 1×10 -1 M to 5×10 -4 M, 10 -1 M to 10 -3 M, 1×10 -1 M to 5×10 -3 M, 10 -1 M to 10 -2 M, 10 -2 M to 10 -6 M, 1×10 -2 M to 5×10 -6 M, 10 -2 M to 10 - 5 M, 1×10 -2 M to 5×10 -5 M, 10-2 M to 10 -4 M, 1×10 -2 M to 5×10 -4 M, 10 -2 M to 10 -3 M, 10 -3 M to 10 -6 M, 1×10 -3 M to 5×10 -6 M, 10 -3 M to 10 -5 M, 1×10 -3 M to 5×10 -5 M, 10 -3 M to 10 -4 M, 10 -4 M to 10 -6 M, 1×10 -4 M to 5×10 -6 M, 10 -4 M to 10 -5 M, 10 -5 M to 10 -6 M.

[0153] In some embodiments, when it is stated that an anti-MASP3 antibody specifically recognizes a MASP3 target with high binding affinity and binds to a non-target with low binding affinity, the Kd value of the anti-MASP3 antibody binding to the MASP3 target is 10 -7 M to 10 - 13 M (e.g. 10 -7 M to 10 -13 M, 10 -8 M to 10 -13 M, 10 -9 M to 10 -13 M, 10 -10 M to 10 -12 M), and the Kd value for binding to non-target is 10 -1 M to 10 -6 M (e.g. 10 -1 M to 10 -6 M, 10 -1 M to 10 -5 M, 10 -2 M to 10 -4 M).

[0154] In some embodiments, when it is mentioned that an anti-MASP3 antibody specifically recognizes MASP3, the binding affinity of the anti-MASP3 antibody is compared with the binding affinity of a control anti-MASP3 antibody (e.g., OMS906). In some embodiments, the Kd value of the binding between the control anti-MASP3 antibody and MASP3 can be at least 2 times, such as 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, 10-100 times, 100-1000 times, 1 ... 3 -10 4 times.

[0155] Nucleic Acids

[0156] Nucleic acid molecules encoding anti-MASP3 antibodies are also contemplated. In some embodiments, a nucleic acid (or a group of nucleic acids) encoding a full-length anti-MASP3 antibody is provided, including any full-length anti-MASP3 antibody described herein. In some embodiments, the nucleic acid (or a group of nucleic acids) of the anti-MASP3 antibody described herein may also include a nucleic acid sequence encoding a polypeptide tag (e.g., a protein purification tag, a His tag, an HA tag).

[0157] Also contemplated herein are isolated host cells comprising an anti-MASP3 antibody, isolated nucleic acids encoding an anti-MASP3 antibody polypeptide component, or vectors comprising nucleic acids encoding an anti-MASP3 antibody polypeptide component as described herein.

[0158] The present application also includes variants of these nucleic acid sequences. For example, the variant includes a nucleotide sequence that hybridizes to the nucleic acid sequence encoding the anti-MASP3 antibody of the present application under at least moderately stringent hybridization conditions.

[0159] The present application also provides a vector into which the nucleic acid sequence of the present application can be inserted.

[0160] Briefly, a natural or synthetic nucleic acid encoding an anti-MASP3 antibody is inserted into a suitable expression vector such that the nucleic acid is operably linked to 5' and 3' regulatory elements, such as a promoter (e.g., a lymphocyte-specific promoter) and a 3' untranslated region (UTR), and the anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody) can be expressed. The vector can be suitable for replication and integration in eukaryotic host cells. Typical cloning and expression vectors contain transcriptional and translational terminators, initiation sequences, and promoters that regulate the expression of the target nucleic acid sequence.

[0161] The nucleic acids described herein can also be used for nucleic acid immunization and gene therapy by using standard gene delivery protocols. Nucleic acid delivery methods are known in the art. For example, see US Pat. Nos. 5,399,346, 5,580,859, 5,589,466, which are incorporated herein by reference in their entirety. In some embodiments, the present application also provides gene therapy vectors.

[0162] Nucleic acids can be cloned into many types of vectors. For example, nucleic acids can be cloned into vectors including, but not limited to, plasmids, phagemids, phage derivatives, animal viruses, and cosmids. Vectors of particular interest include expression vectors, replication vectors, probe generation vectors, and sequencing vectors.

[0163] In addition, the expression vector can be provided to the cell in the form of a viral vector. Viral vector technology is well known in the art and is described in, for example, Green and Sambrook (2013, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, New York), and other virology or molecular biology manuals. Viruses that can be used as vectors include, but are not limited to, retroviruses, adenoviruses, adeno-associated viruses, herpes viruses, and slow viruses. Typically, suitable vectors include a replication origin that works in at least one organism, a promoter sequence, a convenient restriction endonuclease site, and one or more selection markers (see, for example, WO 01 / 96584; WO 01 / 29058; and US Pat. No. 6,326,193).

[0164] Many virus-based systems have been developed for transferring genes into mammalian cells. For example, retroviruses provide a convenient platform for gene delivery systems. The selected gene can be inserted into a vector and packaged in retroviral particles using techniques known in the art. The recombinant virus is then isolated and delivered to the cells of the subject in vivo or in vitro. Many retroviral systems are known in the art. In some embodiments, adenoviral vectors are used. Many adenoviral vectors are known in the art. In some embodiments, lentiviral vectors are used. Vectors derived from retroviruses, such as lentiviruses, are suitable tools for achieving long-term gene transfer because they allow long-term stable integration of transgenes and reproduction in daughter cells. Lentiviral vectors have additional advantages over retroviruses derived from tumors, such as mouse leukemia viruses, because they can transduce non-dividing cells, such as hepatocytes. At the same time, it also has the additional advantage of low immunogenicity.

[0165] Other promoter elements, such as enhancers, regulate the frequency of transcription initiation. They are usually located 30-110 bp upstream of the start site, although recently it has been discovered that many promoters also contain functional elements downstream of the start site. The spacing between promoter elements is usually flexible, so that the promoter function is maintained when the elements are interchanged or moved relative to each other. In the thymidine kinase (tk) promoter, the activity begins to decline only when the spacing between promoter elements increases to 50 bp.

[0166] An example of a suitable promoter is the immediate early cytomegalovirus (CMV) promoter sequence. This promoter sequence is a very strong constitutive promoter sequence that can drive any polynucleotide sequence operably connected thereto to express at a high level. Another example of a suitable promoter is the elongation factor 1α (EF-1α) promoter. However, other constitutive promoters may also be used, including but not limited to the simian virus 40 (SV40) early promoter, mouse mammary tumor virus (MMTV), human immunodeficiency virus long terminal repeat (HIV-LTR) promoter, MoMuLV promoter, avian leukosis virus promoter, Epstein-Barr virus immediate early promoter, Rous sarcoma virus promoter, and human gene promoters, including but not limited to actin promoter, myosin promoter, hemoglobin promoter, and creatine kinase promoter. In addition, the present application should not be limited to using only constitutive promoters, and inducible promoters are also considered in the present application. The use of an inducible promoter provides a molecular switch that turns on the expression of a polynucleotide sequence to which it is operably linked when such expression is desired and turns off expression when it is not desired. Inducible promoters include, but are not limited to, metallothionein promoters, glucocorticoid promoters, progesterone promoters, and tetracycline promoters.

[0167] In some embodiments, expression of the anti-MASP3 antibody is inducible. In some embodiments, the nucleic acid sequence encoding the anti-MASP3 antibody is operably linked to an inducible promoter, including any of the inducible promoters described herein.

[0168] Inducible promoter

[0169] The use of an inducible promoter provides a molecular switch that turns on the expression of a polynucleotide sequence operably linked thereto when expression is desired, and turns off expression when expression is not desired. Exemplary inducible promoters suitable for use in eukaryotic cells include, but are not limited to, hormone-regulated elements (e.g., see Mader, S. and White, JH (1993) Proc. Natl. Acad. Sci. USA 90:5603-5607), synthetic ligand-regulated elements (see Spencer, DM et al (1993) Science 262:1019-1024), and ionizing radiation-regulated elements (see Manome, Y. et al (1993) Biochemistry 32:10607-10613; Datta, R. et al (1992) Proc. Natl. Acad. Sci. USA 89:1014-10153). Other exemplary inducible promoters suitable for use in in vivo or in vitro mammalian systems are described in Gingrich et al. (1998) Annual Rev. Neurosci 21:377-405. In some embodiments, the inducible promoter system used to express anti-MASP3 antibodies is the Tet system. In some embodiments, the inducible promoter system used to express anti-MASP3 antibodies is the E. coli lac repression system.

[0170] An exemplary inducible promoter system used in the present application is the Tet system. The system is based on the Tet system described by Gossen et al. (1993). In an exemplary embodiment, the target polynucleotide is controlled by a promoter comprising one or more Tet operator (TetO) sites. In the inactive state, the Tet repressor (TetR) binds to the TetO site and inhibits transcription of the promoter. In the activated state, for example, in the presence of an inducer such as tetracycline (Tc), anhydrotetracycline, doxycycline (Dox) or its active analogs, the inducer releases TetR from TetO, thereby causing transcription to occur. Doxycycline is a member of the tetracycline antibiotic family, and its chemical name is 1-dimethylamino-2,4a,5,7-pentahydroxy-11-methyl-4,6-dioxy-1,4a,11,11a,12,12a-hexahydrotetraene-3-carboxamide.

[0171] In one embodiment, TetR is codon optimized for expression in mammalian cells, such as mice or human cells. Due to the degeneracy of the genetic code, most amino acids are encoded by more than one codon, so that the sequence of a given nucleic acid has a large number of variants, and the amino acid sequence encoded by it does not change at all. However, many organisms have differences in codon usage, also known as "codon preference" (i.e., the preference for using specific codons for a given amino acid). Codon preference is generally related to the presence of a dominant tRNA species for a specific codon, which in turn improves the efficiency of mRNA translation. Therefore, coding sequences derived from specific species (e.g., prokaryotes) can be customized by codon optimization to improve their expression in different species (e.g., eukaryotes).

[0172] Other specific variants of the Tet system include the following "Tet-Off" and "Tet-On" systems. In the Tet-off system, transcription is inactivated in the presence of Tc or Dox. In this system, a tetracycline-regulated transcription activator protein (tTA), which is composed of a fusion of TetR and the strong transcription activation domain of herpes simplex virus VP16, regulates the expression of the target nucleic acid under the transcriptional control of a tetracycline-responsive promoter element (TRE). The TRE element consists of a fusion of the TetO sequence in series with a promoter (usually a minimal promoter sequence derived from the immediate early promoter of human cytomegalovirus). In the absence of Tc or Dox, tTA binds to TRE and activates transcription of the target gene. In the presence of Tc or Dox, tTA cannot bind to TRE and the target gene cannot be expressed.

[0173] In contrast, in the Tet-On system, transcription is activated in the presence of Tc or Dox. The Tet-On system is based on the reverse tetracycline-regulated transcription activator rtTA. Like tTA, rtTA is a fusion protein consisting of the TetR repressor and the VP16 transcription activation domain. However, changes in four amino acids in the DNA binding region of TetR alter the binding properties of rtTA, allowing it to only recognize the tetO sequence on the target transgene TRE in the presence of Dox. Therefore, in the Tet-On system, rtTA can only activate the transcription of the target gene regulated by the TRE in the presence of Dox.

[0174] Another inducible promoter system is the lac repressor system of Escherichia coli (see Brown et al., Cell 49: 603-612 (1987)). The lac repressor system functions by regulating the transcription of a target polynucleotide operably linked to a promoter comprising a lac operator (lacO). The lac repressor (lacR) binds to LacO, thereby preventing transcription of the target polynucleotide. Expression of the target polynucleotide is induced by a suitable inducer, for example, isopropyl-β-D-thiogalactopyranoside (IPTG).

[0175] In order to evaluate the expression of polypeptide or part thereof, the expression vector to be introduced into the cell may also contain a selectable marker gene or a reporter gene or both, so as to identify and select expressing cells from a cell population transfected or infected by a viral vector. In other aspects, the selectable marker may be carried on a separate DNA fragment and used in a co-transfection experiment. Either the selectable marker gene or the reporter gene may be flanked by a suitable regulatory sequence to enable expression in the host cell. Useful selectable markers include, for example, antibiotic resistance genes, such as neo and similar genes.

[0176] Reporter genes can be used to identify potential transfected cells and evaluate the function of regulatory sequences. Generally, reporter genes are genes that are not present in or expressed by receptor organisms or tissues, and encode a polypeptide whose expression is expressed as some easily detectable characteristics, such as enzyme activity. After DNA is introduced into the receptor cells, the expression of the reporter gene is detected at the appropriate time. Suitable reporter genes may include genes encoding luciferase, beta-galactosidase, chloramphenicol acetyltransferase, secreted alkaline phosphatase or green fluorescent protein (see, Ui-Tel et al., 2000 FEBS Letters 479: 79-82). Suitable expression systems are well known and can be prepared by known techniques or obtained commercially. Generally, the construct of the minimum 5' flanking region that can show the highest expression level of the reporter gene is identified as a promoter. Such promoter regions can be connected to reporter genes and used to evaluate the ability of certain substances in regulating promoter-driven transcription.

[0177] In some embodiments, nucleic acids encoding any of the full-length anti-MASP3 antibodies described herein are provided. In some embodiments, the nucleic acids include one or more nucleic acid sequences encoding the heavy and light chains of the full-length anti-MASP3 antibodies. In some embodiments, each of the one or more nucleic acid sequences is contained in a separate vector. In some embodiments, at least some of the nucleic acid sequences are contained in the same vector. In some embodiments, all nucleic acid sequences are contained in the same vector. The vector can be selected from, for example, a mammalian expression vector and a viral vector (e.g., a vector derived from a retrovirus, an adenovirus, an adeno-associated virus, a herpes virus, and a lentivirus).

[0178] Methods for introducing genes into cells and expressing them are known in the art. In the context of expression vectors, the vectors can be easily introduced into host cells, such as mammalian cells, bacteria, yeast or insect cells, by any method in the art. For example, the expression vector can be introduced into the host cell by physical, chemical or biological methods.

[0179] Physical methods for introducing polynucleotides into host cells include calcium phosphate precipitation, liposome transfection, biolistic methods, microinjection, electroporation, and the like. Methods for preparing cells containing vectors and / or exogenous nucleic acids are well known in the art. See, for example, Green and Sambrook (2013, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, New York). In some embodiments, polynucleotides are introduced into host cells by calcium phosphate transfection.

[0180] Biological methods for introducing target polynucleotides into host cells include the use of DNA and RNA vectors. Viral vectors, particularly retroviral vectors, have become the most widely used methods for inserting genes into mammalian cells, such as human cells. Other viral vectors can be derived from lentiviruses, poxviruses, herpes simplex virus type 1, adenoviruses, and adeno-associated viruses, etc. See, for example, US Pat. Nos. 5,350,674 and 5,585,362.

[0181] Chemical methods for introducing polynucleotides into host cells include colloidal dispersion systems, such as polymer complexes, nanocapsules, microspheres, magnetic beads, and lipid-based systems, including oil-in-water emulsions, micelles, mixed micelles, and liposomes. An exemplary colloidal system used as a delivery vehicle in vivo and in vitro is a liposome (e.g., an artificial membrane vesicle).

[0182] In the case of using a non-viral delivery system, an exemplary delivery vehicle is a liposome. It is contemplated that a lipid formulation is used to import nucleic acid into a host cell (in vitro, in vitro or in vivo). On the other hand, the nucleic acid can be combined with a lipid. Nucleic acids combined with lipids can be wrapped into the aqueous interior of the liposome, dispersed in the lipid bilayer of the liposome, connected to the liposome by a linker molecule combined with the liposome and the oligonucleotide, embedded in the liposome, forming a complex with the liposome, dispersed in a solution containing lipids, mixed with lipids, combined with lipids, suspended in lipids, contained in micelles or mixed with micelles, or otherwise combined with lipids. The compositions related to lipids, lipid / DNA or lipid / expression vectors are not limited to any particular structure in solution. For example, they may exist in a bilayer structure, in micelles or in a "collapsed" structure. They can also be simply dispersed in a solution, possibly forming aggregates of uneven size or shape. Lipids are fatty substances, which can be naturally occurring or synthetic lipids. For example, lipids include fat droplets naturally present in the cytoplasm, as well as a class of compounds containing long-chain aliphatic hydrocarbons and their derivatives, such as fatty acids, alcohols, amines, amino alcohols, and aldehydes.

[0183] Regardless of the method used to introduce exogenous nucleic acid into the host cell or otherwise expose the cell to the inhibitor of the present application, a variety of experiments can be performed to confirm that the recombinant DNA sequence is present in the host cell. Such experiments include, for example, "molecular biology" experiments well known to those skilled in the art. For example, Southern and Northern blotting, RT-PCR and PCR; "biochemical" experiments, such as detecting the presence or absence of a particular polypeptide, such as by immunological methods (ELISAs and Western blots) or by the experiments described herein, are all within the scope of the present application.

[0184] Preparation of anti-MASP3 antibodies

[0185] In some embodiments, the anti-MASP3 antibody is a monoclonal antibody or is derived from a monoclonal antibody. In some embodiments, the anti-MASP3 antibody comprises a V from a monoclonal antibody. H and V L , or a variant thereof. In some embodiments, the anti-MASP3 antibody further comprises a C from a monoclonal antibody. H 1 and C L Region, or variants thereof. Monoclonal antibodies can be prepared using methods known in the art, such as hybridoma cell methods, phage display methods, or using recombinant DNA methods. In addition, exemplary phage display methods are described herein and in the following examples.

[0186] In the hybridoma method, an immunizing agent is usually used to immunize hamsters, mice or other suitable host animals to induce lymphocytes that produce or are capable of producing antibodies that specifically bind to the immunizing agent. Alternatively, lymphocytes can be immunized in vitro. The immunizing agent may include a polypeptide or fusion protein of the target protein. Usually, if human cells are needed, peripheral blood lymphocytes (PBLs) are used, and if non-human mammalian cells are needed, spleen cells or lymph node cells are used. Lymphocytes are fused with immortal cell lines using an appropriate fusion agent, such as polyethylene glycol, to form hybridoma cells. Immortal cell lines are usually transformed mammalian cells, especially myeloma cells of rodents, bovines and humans. Rat or mouse myeloma cell lines are usually used. Hybridoma cells can be cultured in a suitable culture medium, and the culture medium preferably contains one or more substances that inhibit the growth or survival of unfused immortal cells. For example, if the parental cells lack the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT or HPRT), the hybridoma cell culture medium typically includes hypoxanthine, aminopterin, and thymidine (HAT medium), which prevents the growth of HGPRT-deficient cells.

[0187] In some embodiments, the immortalized cell line is effectively fused, and the antibody is stably expressed at a high level by the selected antibody production cells, and is sensitive to certain culture media, such as HAT culture media. In some embodiments, the immortalized cell line is a mouse myeloma cell line, which can be obtained from, for example, the Salk Cell Collection in San Diego, California and the American Type Culture Collection in Manassas, Virginia. Human myeloma and mouse-human hybrid myeloma cell lines are also described for the preparation of human monoclonal antibodies.

[0188] The presence of monoclonal antibodies against the polypeptide in the culture medium of the hybridoma cells can then be determined. The binding specificity of the monoclonal antibodies produced by the hybridoma cells can be determined by immunoprecipitation or in vitro binding experiments, such as radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA). Such techniques or analytical methods are known in the art. The binding affinity of the monoclonal antibodies can be determined by, for example, Scatchard analysis as described in Munson and Pollard, Anal. Biochem., 107:220 (1980).

[0189] After identifying the desired hybridoma cells, the target clones can be subcloned by limiting dilution and cultured by standard methods. Suitable culture media for this purpose include, for example, modified Eagle medium (DMEM) and RPMI-1640 culture media. Alternatively, hybridoma cells can be grown in mammals in the form of ascites.

[0190] The monoclonal antibodies secreted by the subclones can be isolated or purified from the culture medium or ascites fluid by conventional immunoglobulin purification procedures, such as protein A-Sepharose, hydroxylapatite chromatography, gel electrophoresis, dialysis, or affinity chromatography.

[0191] In some embodiments, according to any of the anti-MASP3 antibodies described herein, the anti-MASP3 antibody comprises the sequence of a clone selected from an antibody library (e.g., a phage library displaying scFv or Fab fragments). The clone can be identified by a method for screening a combinatorial library of antibody fragments having a desired activity. For example, a variety of methods are known in the art for generating phage display libraries and screening these libraries to obtain antibodies with desired binding properties. These methods are reviewed, for example, in Hoogenboom et al., Methods in Molecular Biology 178:1-37 (O'Brien et al., ed., Human Press, Totowa, NJ, 2001), and in, for example, McCafferty et al., Nature 348:552-554; Clackson et al., Nature 352:624-628 (1991); Marks et al., J. Mol. Biol. 222:581-597 (1992); Marks and Bradbury, Methods in Molecular Biology 248:161-175 (Lo, ed., Human Press, Totowa, NJ, 2003); Sidhu et al., J. Mol. Biol. 338(2):299-310 (2004); Lee et al., Nature 349:551-554 (1991); al., J. Mol. Biol. 340(5):1073-1093 (2004); Fellouse, Proc. Natl. Acad. Sci. USA 101(34):12467-12472 (2004); and Lee et al., J. Immunol. Methods 284(1-2):119-132 (2004).

[0192] In some phage display methods, V H and V LAll components of the gene are randomly recombined in a phage library, and then phages that can bind to the antigen are screened, as described in Winter et al., Ann. Rev. Immunol., 12: 433-455 (1994). Phages usually display antibody fragments in the form of scFv fragments or Fab fragments. Library phages of immune origin provide high-affinity antibodies against immunogens without the need to construct hybridoma cells. Alternatively, natural libraries (e.g., from humans) can be cloned to provide a single source of antibodies against a variety of non-self antigens and self antigens without any immunization, as described in Griffiths et al., EMBO J, 12: 725-734 (1993). Finally, natural libraries can also be prepared by cloning non-rearranged V-gene fragments from stem cells and using PCR primers containing random sequences to encode CDR3 hypervariable regions and complete rearrangement in vitro, as described in Hoogenboom and Winter, J. Mol. Biol., 227: 381-388 (1992). Patent publications describing human antibody phage libraries include, for example, US Pat. No. 5,750,373 and US Patent Publication Nos. 2005 / 0079574, 2005 / 0119455, 2005 / 0266000, 2007 / 0117126, 2007 / 0160598, 2007 / 0237764, 2007 / 0292936 and 2009 / 0002360.

[0193] The anti-MASP3 antibody is prepared by screening the anti-MASP3 antibody portion in the library by phage display. The library can be a human scFv phage display library with at least 1×10 9 (For example, at least 1×10 9 , 2.5×10 9 , 5×10 9 , 7.5×10 9 , 1×10 10 , 2.5×10 10 , 5×10 10 , 7.5×10 10 or 1×10 11) kinds of diverse unique human antibody fragments. In certain embodiments, the library is a human natural library, constructed by DNA extracted from PMBCs and spleen of healthy subjects, comprising all heavy and light chain subfamilies. In certain embodiments, the library is a human natural library, constructed by DNA extracted from PMBCs isolated from various disease patients, such as patients with autoimmune diseases, cancer patients and patients with infectious diseases. In certain embodiments, the library is a semisynthetic human library, wherein the heavy chain CDR3 is completely random, and all amino acids (except cysteine) are present in any given position with the same probability. (See, for example, Hoet, RMet al., Nat.Biotechnol.23 (3): 344-348, 2005). In certain embodiments, the heavy chain CDR3 length of the semisynthetic human library is between 5 and 24 (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24) amino acids. In some embodiments, the library is a fully synthetic phage display library. In some embodiments, the library is a non-human phage display library.

[0194] Phage clones with high affinity to the target MASP3 can be screened by iterative binding of phage to the target MASP3, which is bound to a solid support (e.g., beads for solution panning or mammalian cells for cell panning), followed by removal of unbound phage and elution of specifically bound phage. Subsequently, bound phage clones are eluted and used to infect appropriate host cells, such as E. coli XL1-Blue, for expression and purification. Phage clones that specifically bind to MASP3 can be enriched by multiple rounds of panning (e.g., 2, 3, 4, 5, 6 or more rounds), such as solution panning, cell panning, or a combination of both. The specific binding of the enriched phage clones to the target MASP3 can be detected by any method known in the art, including, for example, ELISA and FACS.

[0195] Another method for screening antibody libraries is to display proteins on the surface of yeast cells. Wittrup et al. (U.S. Pat. Nos. 6,699,658 and 6,696,251) developed a method for displaying libraries in yeast cells. In this yeast display system, one component includes a yeast lectin protein (Aga1) anchored to the yeast cell wall, and another component includes the second subunit of the lectin protein Aga2, which can be displayed on the surface of yeast cells by binding to the Aga1 protein through a disulfide bond. The Aga1 protein is expressed by integrating the Aga1 gene into the yeast chromosome. The single-chain variable fragment (scFv) library is fused to the Aga2 gene in the yeast display plasmid, and after transformation, the library can be retained in the yeast due to the presence of an additional nutritional marker. Both Aga1 and Aga2 proteins are expressed under the control of a galactose-inducible promoter.

[0196] Human antibody V gene library (V H and V K The fragments were obtained by PCR using a set of degenerate primers (Sblattero, D. and Bradbury, A. Immunotechnology 3, 271-278 1998). The PCR templates were derived from commercially available RNA or cDNA, including PBMC, spleen, lymph node, bone marrow and tonsil. H and V K After the PCR libraries were combined, they were assembled into scFv format by overlap extension PCR (Sheets, MD et al, Proc. Natl. Acad. Sci. USA 95, 6157–6162 1998). In order to construct a yeast scFv display library, the obtained scFv PCR products were cloned into a yeast display plasmid in yeast by homologous recombination. (Chao, G, et al, Nat Protoc. 2006; 1(2): 755-68. Miller KD, et al. Current Protocols in Cytometry 4.7.1-4.7.30, 2008).

[0197] Anti-MASP3 antibodies can be screened using mammalian cell display systems, where the antibody portion is displayed on the cell surface and antibodies that specifically target MASP3 are isolated by antigen-directed screening methods (as described in US patent No. 7,732,195B2). A Chinese hamster ovary (CHO) cell library displaying a large number of human IgG antibody genes can be established and used to find clones expressing high-affinity antibody genes. Another display system has been developed that allows the same protein to be displayed and secreted simultaneously on the cell surface through alternative splicing, where the displayed protein phenotype remains associated with the genotype, allowing the secreted soluble antibody to be characterized in both biophysical and cell function-based assays. This method overcomes many of the limitations of previous mammalian cell displays and enables direct screening and maturation of full-length, glycosylated IgGs as antibodies (Peter M. Bowers, et al, Methods 2014, 65: 44-56). Transient expression systems are suitable for a single round of antigen selection prior to antibody gene recovery and are therefore most useful for selecting antibodies from smaller libraries. Stable exosome vectors offer an attractive alternative. Exosome vectors can be efficiently transfected and stably maintained at low copy numbers, allowing multiple rounds of panning and the resolution of more complex antibody repertoires.

[0198] The IgG library was constructed based on the ligation of germline sequence V gene segments isolated from a group of human donors and rearranged (D)J regions. RNA collected from 2000 human blood samples was reverse transcribed into cDNA and the V H and V K Specific primers amplify V H and V K The fragment was purified by gel extraction. H and V K The fragments were subcloned into display vectors containing IgG1 or K constant regions, and then electroporated or transduced into 293T cells to prepare IgG libraries. H and V K To generate scFv, which is then subcloned into a display vector and electroporated or transduced into 293T cells. As is well known, IgG libraries are constructed based on germline sequence V gene segments and rearranged (D)J regions isolated from a group of donors, which can be mice, rats, rabbits or monkeys.

[0199] Monoclonal antibodies can also be prepared by recombinant DNA methods, such as described in US Patent No. 4,816,567. The DNA encoding the monoclonal antibodies described in the present application can be easily isolated and sequenced by conventional methods (e.g., by oligonucleotide probes that can specifically bind to the genes encoding the light and heavy chains of mouse antibodies). The hybridoma cells described above or the MASP3-specific phage clones of the present application can be used as the source of such DNA. After isolation, the DNA can be placed in an expression vector, and then the vector can be transfected into a host cell, such as a simian COS cell, a Chinese hamster ovary carcinoma (CHO) cell, or a myeloma cell that does not produce immunoglobulins, to obtain monoclonal antibodies synthesized in recombinant host cells. The DNA can also be modified, such as replacing the human heavy and light chain constant regions with coding sequences and / or replacing the homologous non-human sequences with framework regions (US Patent No. 4,816,567; Morrison et al., supra), or by covalently linking all or part of the coding sequence of an immunoglobulin coding sequence to the coding sequence of a non-immunoglobulin polypeptide. This non-immunoglobulin polypeptide can replace the constant region of the antibody in the present application, or can replace one antigen binding site in the variable domain of the antibody in the present application to form a chimeric bivalent antibody.

[0200] The antibody can be a monovalent antibody. Methods for preparing monovalent antibodies are known in the art. For example, a recombinant expression method involving immunoglobulin light chains and modified heavy chains. The heavy chains are usually truncated at any position in the Fc region to prevent the heavy chains from cross-linking with each other. Alternatively, the relevant cysteine ​​residues are replaced by other amino acid residues or are deleted to prevent cross-linking.

[0201] In vitro methods are also suitable for preparing monovalent antibodies. Digestion of antibodies to produce antibody fragments, particularly Fab fragments, can be accomplished using any method known in the art.

[0202] Antibody variable domains with the desired binding specificities (antibody-antigen combining sites) can be fused to immunoglobulin constant regions. Preferably, the fusion is to an immunoglobulin heavy chain constant region, which includes at least part of the hinge, C H 2 and C H In some embodiments, the first heavy chain constant region (C H 1) At least in one fusion. DNA encoding the immunoglobulin heavy chain fusion, and if desired, DNA encoding the immunoglobulin light chain, is inserted into separate expression vectors and co-transfected into a suitable host organism.

[0203] Fully human and humanized antibodies

[0204] The anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) can be a fully human antibody or a humanized antibody. The humanized form of the non-human (e.g., mouse) antibody portion is a chimeric immunoglobulin, immunoglobulin chain, or fragment thereof (e.g., Fv, Fab, Fab', F(ab')2, scFv, or other antigen-binding subsequences of an antibody), which generally includes minimal sequences derived from non-human immunoglobulins. Humanized antibodies include human immunoglobulins, immunoglobulin chains, or fragments thereof (acceptor antibodies), wherein residues of the acceptor CDRs are replaced by residues of non-human (donor antibody) CDRs having the desired specificity, affinity, and performance, such as mouse, rat, or rabbit CDRs. In some embodiments, human immunoglobulin Fv framework region residues are replaced by corresponding non-human residues. Humanized antibodies may also contain amino acid residues that are neither in the acceptor antibody nor in the introduced CDR or framework region sequences. Generally, a humanized antibody comprises at least one, and typically two, variable domains, in which all or substantially all CDR regions correspond to those of a non-human immunoglobulin and all or substantially all framework regions are human immunoglobulin consensus sequences.

[0205] Typically, a humanized antibody contains one or more amino acid residues introduced from a non-human source. Those non-human amino acid residues are generally referred to as "imported" residues, usually from "imported" variable domains. According to some embodiments, humanization can be performed substantially according to the following method of Winter and his colleagues (Jones et al., Nature, 321: 522-525 (1986); Riechmann et al., Nature, 332: 323-327 (1988); Verhoeyen et al., Science, 239: 1534-1536 (1988)), by replacing the corresponding sequence of a human antibody with rodent CDRs or CDR sequences. Therefore, this "humanized" antibody portion (US Patent No. 4,816,567), which is substantially less than a complete human antibody, has its variable domains replaced by corresponding sequences from non-human sources. In practice, the humanized antibody portion is a typical human antibody portion in which some CDR residues and possibly some framework region residues are substituted by residues from analogous sites in rodent antibodies.

[0206] Fully human antibodies are an alternative to humanization. For example, transgenic animals (e.g., mice) that can produce a complete library of fully human antibodies after immunization without producing endogenous immunoglobulins can now be prepared. For example, it has been reported that homozygous deletion of the antibody heavy chain joining region (JH) gene in chimeric and germline mutant mice completely inhibits the production of endogenous antibodies. Transferring the human germline immunoglobulin gene array into such germline mutant mice can produce human antibodies under antigen stimulation, see, for example, akobovits et al., PNAS USA, 90: 2551 (1993); Jakobovits et al., Nature, 362: 255-258 (1993); Bruggemann et al., Year in Immunol., 7: 33 (1993); US Patent Nos. 5,545,806, 5,569,825, 5,591,669, 5,545,807; and WO 97 / 17852. Alternatively, fully human antibodies can be prepared by introducing human immunoglobulin loci into transgenic animals (e.g., mice in which endogenous immunoglobulin genes have been partially or completely silenced). After antigen stimulation, it can be found that the production of fully human antibodies is very similar to its production in humans in all aspects, including gene rearrangement, assembly, and antibody libraries. This method is described in, for example, US Patent Nos. 5,545,807; 5,545,806; 5,569,825; 5,625,126; 5,633,425; and 5,661,016, and Marks et al., Bio / Technology, 10:779-783 (1992); Lonberg et al., Nature, 368:856-859 (1994); Morrison, Nature, 368:812-813 (1994); Fishwild et al., Nature Biotechnology, 14:845-851 (1996); Neuberger, Nature Biotechnology, 14:826 (1996); Lonberg and Described in Huszar, Intern. Rev. Immunol., 13:65-93 (1995).

[0207] Fully human antibodies can also be produced by in vitro activated B cells (see US Patents 5,567,610 and 5,229,275) or by using various techniques known in the art, including phage display libraries. Hoogenboom and Winter, J. Mol. Biol., 227:381 (1991); Marks et al., J. Mol. Biol., 222:581 (1991). The techniques of Cole et al. and Boerner et al. can also be used to prepare fully human monoclonal antibodies. See Cole et al., Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, p.77 (1985) and Boerner et al., J. Immunol., 147 (1): 86-95 (1991).

[0208] Anti-MASP3 antibody variants

[0209] In some embodiments, the amino acid sequences of anti-MASP3 antibody variants (e.g., full-length anti-MASP3 antibodies) provided herein are also contemplated. For example, it may be desirable to improve the binding affinity and / or other biological activities of the antibody. The amino acid sequence of the antibody variant may be prepared by introducing appropriate modifications into the nucleotide sequence encoding the antibody or by peptide synthesis. Such modifications include, for example, deletions and / or insertions and / or substitutions of residues in the antibody amino acid sequence. The final construction may be completed by any combination of deletions, insertions, and substitutions of amino acid residues to give it the desired characteristics. For example, antigen binding.

[0210] In some embodiments, anti-MASP3 antibody variants having one or more amino acid substitutions are provided. The target sites for substitution mutations include hypervariable regions (HVRs) and framework regions (FRs). Amino acid substitutions can be introduced into the target antibody and the product screened for the desired activity, for example, improved biological activity, maintained / improved antigen binding ability, reduced immunogenicity, or improved ADCC or CDC.

[0211] Conservative substitutions are shown in Table 4 below.

[0212] Table 4 Conservative substitutions

[0213]

[0214]

[0215] Amino acids are divided into different categories based on the properties of their side chains:

[0216] a. Hydrophobic amino acids: Norleucine, Met, Ala, Val, Leu, Ile;

[0217] b. Neutral hydrophilic amino acids: cysteine ​​Cys, serine Ser, threonine Thr, asparagine Asn, glutamine Gln;

[0218] c. Acidic amino acids: Aspartic acid Asp, glutamic acid Glu;

[0219] d. Basic amino acids: histidine His, lysine Lys, arginine Arg;

[0220] e. Contains amino acids that affect the chain direction: glycine Gly, proline Pro;

[0221] f. Aromatic amino acids: tryptophan Trp, tyrosine Tyr, phenylalanine Phe.

[0222] Non-conservative amino acid substitutions include substitutions of one species for another.

[0223] An exemplary substitution variant is an affinity-matured antibody, which can be conveniently produced using, for example, affinity maturation techniques based on phage display. In short, one or more CDR residues are mutated, the variant antibody portion is displayed on the phage, and variants with specific biological activity (e.g., inhibition of enzyme activity or improved antibody affinity) are screened. Changes (e.g., substitutions) can be made in the HVRs region to obtain improved inhibitory activity or antibody affinity. Changes can be made in the "hotspots" of the HVR, i.e., residues encoded by codons that undergo high-frequency mutations during somatic maturation (see, e.g., Chowdhury, Methods Mol. Biol. 207: 179-196 (2008)), and / or at specific determinant residues (SDRs), and the resulting variant V is detected. H and V L Methods for constructing and reselecting affinity maturation from secondary libraries have been described in some literature, for example, Hoogenboom et al. in Methods in Molecular Biology 178: 1-37 (O'Brien et al., ed., Human Press, Totowa, NJ, (2001)).

[0224] In some affinity maturation embodiments, diversity is introduced into the variable genes selected for affinity maturation by any of a variety of methods (e.g., error-prone PCR, chain shuffling, or oligonucleotide directed mutagenesis). A secondary library is then created. The library is screened to identify antibody variants with the desired affinity. Another method for introducing diversity includes HVR-mediated approaches, in which several HVR residues (e.g., 4-6 residues at a time) are randomized. HVR residues involved in antigen binding are specifically identified, for example, using alanine scanning mutagenesis or modeling. Typically, CDR-H3 and CDR-L3 regions are particularly key targets.

[0225] In some embodiments, substitutions, insertions or deletions may occur within one or more HVRs, as long as such changes do not substantially reduce the ability of the antibody to bind antigen. For example, conservative changes (e.g., conservative substitutions provided herein) that do not substantially reduce binding affinity may be produced in HVRs. These changes may occur outside of HVR "hot spots" or SDRs regions. In some embodiments, the variant V provided above H and V L Sequences, each HVR is either unchanged or contains no more than 1, 2 or 3 amino acid substitutions.

[0226] A useful method for identifying amino acid residues or regions in antibodies that can be targeted for mutation is called "alanine scanning mutagenesis", as described in Cunningham and Wells (1989) Science, 244: 1081-1085. In this method, one or a group of target residues (e.g., charged residues such as arginine, aspartic acid, histidine, lysine and glutamic acid) are replaced by neutral or negatively charged amino acids (e.g., alanine or glutamic acid) to determine whether the antibody-antigen interaction is affected. Substitutions can be further introduced at the position of the amino acid to demonstrate that the position is functionally sensitive to the initial substitution. Alternatively or additionally, the contact sites between the antibody and the antigen are identified by the crystal structure of the antigen-antibody complex. These contact site residues and adjacent residues can be targeted or eliminated as substitution candidates. Variants are screened to determine whether they have the desired properties.

[0227] Insertions of amino acid sequences include fusions at the amino and / or carboxyl termini ranging in length from 1 residue to polypeptides containing 100 or more residues, and also include insertions of 1 or more amino acid residues within a sequence. Examples of terminal insertions include antibodies with a methionyl residue at the N-terminus. Other insertion variants of antibody molecules include fusions of an enzyme (e.g., ADEPT) or a polypeptide that increases the serum half-life of the antibody molecule at the N-terminus or C-terminus.

[0228] Fc region variants

[0229] In some embodiments, one or more amino acid modifications are introduced into the Fc region of an antibody described herein (e.g., a full-length anti-MASP3 antibody or an anti-MASP3 antibody fusion protein), thereby generating an Fc region variant. In some embodiments, the Fc region variant has enhanced ADCC potency, which is generally associated with receptors that bind to Fc (FcRs). In some embodiments, the Fc region variant has reduced ADCC potency. There are many examples of how changes or mutations in Fc sequences affect their potency, for example, WO 00 / 42072 and Shields et al. J Biol. Chem. 9 (2): 6591-6604 (2001) describe antibody variants with enhanced or reduced binding to FcRs. The contents of these publications are incorporated herein by reference.

[0230] Antibody-dependent cell-mediated cytotoxicity (ADCC) is the mechanism of action of therapeutic antibodies against tumor cells. ADCC is a cell-mediated immune defense in which effector cells of the immune system actively lyse target cells (e.g., cancer cells) when antigens on the surface of the target cell membrane are bound by specific antibodies (e.g., anti-MASP3 antibodies). Usually, the ADCC effect involves NK cells activated by antibodies. NK cells express the Fc receptor CD16. This receptor recognizes and binds to the Fc portion of antibody molecules bound to the surface of target cells. The most common Fc receptors on the surface of NK cells are CD16 or FcγRIII. The binding of Fc receptors to the Fc region of antibodies leads to the activation of NK cells, the release of cell lytic granules, and subsequent apoptosis of target cells. The killing effect of ADCC on tumor cells can be determined by specific experiments of NK-92 cells transfected with high-affinity FcR. The results are compared with wild-type NK-92 that do not express FcR.

[0231] In some embodiments, the present application also provides anti-MASP3 antibody variants (e.g., full-length anti-MASP3 antibody variants) that contain an Fc region with some but not all effector functions, so that it has an extended half-life in vivo, but a specific effector function (e.g., CDC or ADCC) is unnecessary or harmful, and such anti-MASP3 antibodies become ideal candidates for the present application. The reduction / elimination of CDC and / or ADCC activity is confirmed by in vitro and / or in vivo cytotoxicity assays. For example, an Fc receptor (FcR) binding assay is used to confirm that the antibody lacks FcγR binding ability (and therefore may lack ADCC activity) but still retains FcRn binding ability. Among the main cells that mediate ADCC, NK cells express only FcγRIII, while monocytes express FcγRI, FcγRII, and FcγRIII. The expression of FcR on hematopoietic cells is summarized in Table 3 on page 464 of Ravetch and Kinet Annu. Rev. Immunol. 9: 457-492 (1991). Non-limiting examples of in vitro assessment of ADCC activity of target molecules are described in US Pat. No. 5,500,362 (see, e.g., Hellstrom, I. et al. Proc. Nat'l Acad. Sci. USA 83:7059-7063 (1986) and Hellstrom, I et al., Proc. Nat'l Acad. Sci. USA 82:1499-1502 (1985); US Pat. No. 5,821,337 (see Bruggemann, M. et al., J. Exp. Med. 166:1351-1361 (1987)). Alternatively, non-radioactive detection methods can be used (see, e.g., ACTI TM Flow cytometry nonradioactive cytotoxicity assay (Cell Technology, Inc. Mountain View, Calif.) and CYTOTOX 96 TMNon-radioactive cytotoxicity assays (Promega, Madison, Wis.). Effector cells used in such assays include peripheral blood mononuclear cells (PBMC) and natural killer cells (NK). Alternatively, ADCC activity of the target molecule is tested in vivo, for example, in an animal model as described in Clynes et al. Proc. Nat'l Acad. Sci. USA 95:652-656 (1998). A C1q binding assay can also be performed to confirm that the antibody cannot bind to C1q and thus lacks CDC activity. See, for example, C1q and C3c binding ELISAs in WO 2006 / 029879 and WO 2005 / 100402. To assess complement activation, a CDC assay can be performed (see, e.g., Gazzano-Santoro et al., J. Immunol. Methods 202: 163 (1996); Cragg, MS et al., Blood 101: 1045-1052 (2003); and Cragg, MS and M. J. Glennie, Blood 103: 2738-2743 (2004)). FcRn binding and in vivo clearance / half-life can be determined using methods known in the art (see, e.g., Petkova, SB et al., Int'l. Immunol. 18 (12): 1759-1769 (2006)).

[0232] Antibodies with reduced effector function include substitutions of one or more residues at residues 238, 265, 269, 270, 297, 327, and 329 in the Fc region (US Pat. No. 6,737,056). These Fc variants include Fc variants with substitutions of two or more residues at positions 265, 269, 270, 297, and 327, including an Fc variant known as "DANA" in which residues 265 and 297 are substituted with alanine (US Pat. No. 7,332,581).

[0233] Such antibody variants with improved or reduced binding to FcRs have been described (see, for example, US Pat. No. 6,737,056; WO 2004 / 056312, and Shields et al., J. Biol. Chem. 9(2):6591-6604 (2001)).

[0234] In some embodiments, an anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variant is provided, comprising an Fc region variant having one or more amino acid substitutions capable of enhancing ADCC effects. In some embodiments, the Fc region variant comprises one or more amino acid substitutions capable of enhancing ADCC effects, and the positions of these substitutions are at positions 298, 333, and / or 334 (EU residue numbering) in the Fc region. In some embodiments, the anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variant comprises amino acid substitutions at positions S298A, E333A, and K334A in the Fc region.

[0235] In some embodiments, alterations in the Fc region result in altered (ie, enhanced or reduced) C1q binding and / or complement dependent cytotoxicity (CDC), as described in US Pat. No. 6,194,551, WO 99 / 51642, and Idusogie et al., J. Immunol. 164:4178-4184 (2000).

[0236] In some embodiments, an anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variant is provided, comprising an Fc region variant having one or more amino acid substitutions that can extend half-life or enhance binding to an Fc receptor (FcRn). Antibodies with extended half-life and improved FcRn binding are described in US 2005 / 0014934A1 (Hinton et al.). These antibodies have one or more amino acid substitutions in the Fc region that enhance the binding of the Fc region to FcRn. These Fc variants comprise one or more substitutions at residues 238, 256, 265, 272, 286, 303, 305, 307, 311, 312, 317, 340, 356, 360, 362, 376, 378, 380, 382, ​​413, 424 or 434 in the Fc region, such as a substitution at residue 434 in the Fc region ( US Pat. No. 7,371,826 ).

[0237] See also Duncan & Winter, Nature 322:738-40 (1988); US Pat. No. 5,648,260; US Pat. No. 5,624,821 and WO 94 / 29351 for other examples of Fc region variants.

[0238] The present application contemplates anti-MASP3 antibodies (eg, full-length anti-MASP3 antibodies) comprising any one of the Fc variants described herein, or a combination thereof.

[0239] Glycosylation variants

[0240] In some embodiments, the anti-MASP3 antibodies (e.g., full-length anti-MASP3 antibodies) provided herein are altered to increase or decrease the extent of glycosylation of the anti-NGF antibody. Adding or deleting glycosylation sites on the anti-MASP3 antibody can be conveniently achieved by altering the amino acid sequence of the anti-NGF antibody or a polypeptide portion thereof to add or remove one or more glycosylation sites.

[0241] The anti-MASP3 antibody contains an Fc region, and the sugars attached to it can be changed. Natural antibodies produced by mammalian cells usually contain branched biantennary oligosaccharides, which are usually attached to the Fc region C through N-linkage. H 2 domain Asn297, see, e.g., Wright et al., TIBTECH 15:26-32 (1997). The oligosaccharide may comprise a variety of sugars, such as mannose, N-acetylglucosamine (GlcNAc), galactose and sialic acid, as well as trehalose linked to the GlcNAc in the "stem" of the biantennary oligosaccharide structure. In some embodiments, the anti-MASP3 antibodies of the present application may be oligosaccharide-modified to produce anti-MASP3 antibody variants with certain improved properties.

[0242] C H The N-glycans linked to the 2 domains are heterogeneous. Antibodies or Fc fusion proteins produced in CHO cells are fucosylated by fucosyltransferase activity, see Shoji-Hosaka et al., J. Biochem. 2006, 140: 777-83. Typically, a small fraction of naturally occurring non-fucosylated IgGs can be detected in human serum. N-glycosylation of the Fc region is important for its binding to FcγR; while non-fucosylated N-glycans enhance the binding ability of Fc to FcγRIIIa. Enhanced binding ability to FcRIIIa enhances the ADCC effect, which is advantageous in certain antibody therapeutic applications requiring cytotoxicity.

[0243] In some embodiments, when Fc-mediated cytotoxicity is not required, enhanced effector function may be detrimental. In some embodiments, the Fc fragment or C H 2 domain is non-glycosylated. In some embodiments, by H The N-glycosylation site in the 2 domain was mutated to prevent its glycosylation.

[0244] In some embodiments, anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variants are provided, which comprise an Fc region, wherein the carbohydrate structure attached to the Fc region has reduced fucose or lacks fucose, which may enhance ADCC function. Specifically, anti-MASP3 antibodies are provided herein, which have reduced fucose relative to the same anti-MASP3 antibody produced by wild-type CHO cells. That is, they are characterized by having a lower amount of fucose than antibodies produced by natural CHO cells (e.g., CHO cells that produce a natural glycosylated form, CHO cells containing a natural FUT8 gene). In some embodiments, the N-linked glycans of the anti-MASP3 antibody have less than 50%, 40%, 30%, 20%, 10% or 5% fucose. For example, the fucose content of the anti-MASP3 antibody may be 1%-80%, 1%-65%, 5%-65% or 20%-40%. In some embodiments, the N-linked glycans of the anti-MASP3 antibody do not contain fucose, i.e., the anti-MASP3 antibody is completely free of fucose, or is free of fucose or is defucosylated. The amount of fucose is determined by calculating the average amount of fucose in the sugar chain attached to Asn297 relative to the total amount of all sugar structures (such as complex, hybrid or mannose structures) attached to Asn297 measured by MALDI-TOF mass spectrometry, as described in WO 2008 / 077546. Asn297 refers to the asparagine residue at position 297 of the Fc region (EU Fc region residue numbering system). However, due to minor sequence variations of antibodies, Asn297 may also be located ±3 amino acids upstream or downstream of position 297, i.e., between positions 294 and 300. These fucosylation variants may have enhanced ADCC function. See, for example, US Patent Publication Nos. US 2003 / 0157108 (Presta, L.), US 2004 / 0093621 (Kyowa Hakko Kogyo Co., Ltd).Examples of publications related to "defucosylated" or "fucose-deficient" antibody variants include, US 2003 / 0157108; WO 2000 / 61739; WO 2001 / 29246; US 2003 / 0115614; US 2002 / 0164328; US 2004 / 0093621; US ​​2004 / 0132140; US 2004 / 0110704; US 2004 / 0110282; US 2004 / 0109865; WO 2003 / 085119; WO 2003 / 084570; WO 2005 / 035586; WO 2005 / 035778; WO 2005 / 053742; WO 2002 / 031140; Okazaki et al. J. Mol. Biol. 336:1239-1249 (2004); Yamane-Ohnuki et al. Biotech. Bioeng. 87:614 (2004). Cell lines capable of producing defucosylated antibodies include Lec13 CHO cells lacking protein fucosylation function (Ripka et al. Arch. Biochem. Biophys. 249: 533-545 (1986); US Pat Appl No US2003 / 0157108 A1, Presta, L; and WO 2004 / 056312 A1, Adams et al., especially Example 11), and gene knockout cell lines, such as CHO cells in which the α-1,6-fucosyltransferase gene, FUT8 gene is knocked out (see Yamane-Ohnuki et al. Biotech. Bioeng. 87: 614 (2004); Kanda, Y. et al., Biotechnol. Bioeng., 94 (4): 680-688 (2006); and WO2003 / 085107).

[0245] Anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variants further provide bisected oligosaccharides, for example, wherein the biantennary oligosaccharide attached to the Fc region of the anti-MASP3 antibody is bisected by GlcNAc. Such anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variants may have reduced fucosylation and / or enhanced ADCC function. Examples of such antibody variants are described in WO2003 / 011878 (Jean-Mairet et al.); US Pat. No. 6,602,684 (Umana et al.); US 2005 / 0123546 (Umana et al.), and Ferrara et al., Biotechnology and Bioengineering, 93(5):851-861 (2006). Anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variants are also provided, which have at least one galactose residue in the oligosaccharide attached to the Fc region. Such anti-MASP3 antibody variants may have enhanced CDC function. Such variants are described, for example, in WO 1997 / 30087 (Patel et al.); WO 1998 / 58964 (Raju, S.); and WO 1999 / 22764 (Raju, S.).

[0246] In some embodiments, the anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variant comprises an Fc region that can bind to FcγRIII. In some embodiments, the anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) variant comprising an Fc region has ADCC activity in the presence of human effector cells (e.g., T cells), or has enhanced ADCC activity in the presence of human effector cells compared to an otherwise identical anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) having a human wild-type IgG1 Fc region.

[0247] Cysteine ​​engineered variants

[0248] In some embodiments, it is desirable to prepare cysteine ​​engineered anti-MASP3 antibodies (e.g., full-length anti-MASP3 antibodies) in which one or more amino acid residues are substituted with cysteine ​​residues. In some embodiments, the substituted residues occur at accessible sites of the anti-MASP3 antibody. By replacing those residues with cysteine, reactive sulfhydryl groups are located at accessible sites of the anti-MASP3 antibody, which can be used to conjugate the anti-MASP3 antibody to other moieties, such as drug moieties or linker-drug moieties, to prepare anti-MASP3 immunoconjugates as further described herein. Cysteine ​​engineered anti-MASP3 antibodies (e.g., full-length anti-MASP3 antibodies) can be prepared, for example, as described in US Pat. No. 7,521,541.

[0249] derivative

[0250] In some embodiments, the anti-MASP3 antibodies (e.g., full-length anti-MASP3 antibodies) provided herein can be further modified to include other non-protein moieties that are known in the art and readily available. Suitable moieties for derivatizing anti-MASP3 antibodies include, but are not limited to, water-soluble polymers. Non-limiting examples of water-soluble polymers include, but are not limited to, polyethylene glycol (PEG), ethylene glycol / propylene glycol copolymers, carboxymethyl cellulose, dextran, polyvinyl alcohol, polyvinyl pyrrolidone, poly-1,3-dioxolane, poly-1,3,6-trioxane, ethylene / maleic anhydride copolymers, polyamino acids (homopolymers or random copolymers), dextran or poly(n-vinyl pyrrolidone) polyethylene glycol, propylene glycol homopolymers, propylene oxide / ethylene oxide copolymers, polyoxyethylated polyols (e.g., glycerol), polyvinyl alcohol, and mixtures thereof. Polyethylene glycol propionaldehyde has advantages in manufacturing due to its stability in water. The polymer can have any molecular weight and can be branched or unbranched. The number of polymers attached to the anti-MASP3 antibody can vary, and if more than one polymer is attached, they can be the same or different molecules. In general, the number and / or type of polymers used for derivatization can be determined based on considerations including, but not limited to, whether the properties or functions of the anti-MASP3 antibody are to be improved, whether the anti-MASP3 antibody derivative is to be used for treatment of a particular condition, etc.

[0251] Pharmaceutical composition

[0252] Also provided herein are compositions (e.g., pharmaceutical compositions, also referred to herein as formulations) comprising any anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody), nucleic acids encoding the antibodies, vectors comprising nucleic acids encoding the antibodies, or host cells comprising nucleic acids or vectors described herein. In some embodiments, a pharmaceutical composition is provided, comprising any anti-MASP3 antibody described herein and a pharmaceutically acceptable carrier.

[0253] Suitable anti-MASP3 antibody formulations can be obtained by mixing an anti-MASP3 antibody having the desired purity with an optional pharmaceutically acceptable carrier, excipient or stabilizer (Remington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980)) and prepared in the form of a lyophilized formulation or a liquid formulation. Acceptable carriers, excipients or stabilizers are nontoxic to recipients at the dosages and concentrations used, and include buffers such as phosphates, citric acid and other organic acids; antioxidants, including ascorbic acid and methionine; preservatives (e.g., octadecyldimethylbenzyl ammonium chloride; hexamethylammonium chloride; benzalkonium chloride; benzethonium chloride; phenol; butyl alcohol or benzyl alcohol; alkyl parabens, such as methyl paraben or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol and m-cresol); low molecular weight (less than 1 0 residues) polypeptides; proteins, such as serum albumin, gelatin or immunoglobulins; hydrophilic polymers, such as polyvinylpyrrolidone; amino acids, such as glycine, glutamine, asparagine, histidine, arginine or lysine; monosaccharides, disaccharides and other carbohydrates, including glucose, mannose or dextrin; chelating agents such as EDTA; sugars, such as sucrose, mannitol, trehalose or sorbitol; salt-forming counterions such as sodium; metal complexes (such as zinc-protein complexes); and / or nonionic surfactants such as TWEEN TM , PLURONICS TM or polyethylene glycol (PEG); exemplary formulations are described in WO98 / 56418 and expressly incorporated herein by reference. Lyophilized formulations suitable for subcutaneous administration are described in WO97 / 04801. Such lyophilized formulations can be reconstituted with a suitable diluent to a high protein concentration formulation, and the reconstituted formulation can be administered subcutaneously to the subject to be treated herein. Cationic liposomes or liposomes can be used to deliver the anti-MASP3 antibodies of the present application to cells.

[0254] The formulations described herein may contain, in addition to the anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody), one or more other active substances necessary for treating a specific condition, preferably substances having complementary activities and having no adverse reactions to each other. For example, in addition to the anti-MASP3 antibody, it may be necessary to further contain immunosuppressants, anti-inflammatory drugs, analgesics, other complement inhibitors or vascular inhibitors. These molecules are present in combination in amounts effective for the intended purpose. The effective amount of other substances depends on the amount of anti-MASP3 antibody in the formulation, the type of disease or condition or treatment, and other factors as described above. These drugs are generally used in the same dosages and administration routes as described herein, or in 1% to 99% of the currently used dosages.

[0255] The anti-MASP3 antibody (e.g., full-length anti-MASP3 antibody) can also be entrapped in microcapsules prepared, for example, by coacervation techniques and interfacial polymerization, such as hydroxymethylcellulose or gelatin-microcapsules and poly(methyl methacrylate) microcapsules in colloidal drug delivery systems (e.g., liposomes, albumin microspheres, microemulsions, nanoparticles and nanocapsules) or in macroemulsions, respectively.

[0256] Sustained release preparations can be prepared.

[0257] Sustained-release formulations of anti-MASP3 antibodies (e.g., full-length anti-MASP3 antibodies) can be prepared. Suitable examples of sustained-release formulations include solid hydrophobic polymer semipermeable matrices containing the antibody (or fragment thereof), which are in the form of shaped articles, such as films or microcapsules. Examples of sustained-release matrices include polyesters, hydrogels (e.g., poly(2-hydroxyethyl methacrylate) or poly(vinyl alcohol)), polylactic acid (US Pat. No. 3,773,919), copolymers of L-glutamic acid and ethyl L-glutamate, non-degradable ethylene-vinyl acetate, degradable lactic acid-glycolic acid copolymers such as LUPRON DEPOT™ (injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide acetate), and poly-D(-)-3-hydroxybutyric acid. Although polymers such as ethylene-vinyl acetate and lactic acid-glycolic acid can allow the release of molecules for more than 100 days, certain hydrogels can release proteins in shorter periods of time. When encapsulated antibodies remain in the body for a long time, they may denature or aggregate due to exposure to a humid environment at 37°C, which may lead to loss of biological activity or change in immunogenicity. Rational strategies can be designed to stabilize anti-MASP3 antibodies based on the corresponding mechanisms. For example, if the aggregation mechanism is found to be the formation of intermolecular SS bonds through thiodisulfide exchange, stabilization can be achieved by modifying thiol residues, lyophilizing in acidic solutions, controlling water content, using appropriate additives, and developing specific polymer matrix compositions.

[0258] In some embodiments, the anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody) is formulated in a buffer containing citrate, sodium chloride, acetate, succinate, glycine, polysorbate 80 (Tween 80), or any combination thereof.

[0259] Preparations for in vivo administration must be sterile. This can be easily achieved, for example, by filtration through sterile filtration membranes.

[0260] Therapeutic approaches using anti-MASP3 antibodies

[0261] Anti-MASP3 antibodies (e.g., full-length anti-MASP3 antibodies) and / or compositions described herein can be administered to an individual (e.g., a mammal, such as a human) to treat diseases and / or conditions resulting from a dysregulation of the complement system (e.g., autoimmune diseases, transplant-related diseases, inflammatory diseases, hematological diseases, coagulopathy, angiogenesis-dependent diseases and / or viral infections), including but not limited to ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHU), and glomerular necrosis. S), paroxysmal nocturnal hemoglobinuria (PNH), TMA secondary to transplantation, Upshaw-Schulman syndrome, arthritis, traumatic brain injury, aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection. Therefore, the present application, in some embodiments, provides a method for treating diseases and / or disorders caused by complement system dysregulation (e.g., autoimmune diseases, transplantation-related diseases, inflammatory diseases, blood diseases, coagulation diseases, angiogenesis-dependent diseases and / or viral infectivity), comprising administering to an individual an effective amount of a composition (e.g., a pharmaceutical composition) comprising an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody), such as any anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody) described herein. In some embodiments, the individual is a human.

[0262] For example, in some embodiments, a method for treating an individual with a disease associated with a dysregulation of the complement system (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a pharmaceutical composition comprising a MASP3 antibody (e.g., a full-length anti-MASP3 antibody) that specifically binds to an epitope on human MASP3, wherein the epitope comprises 10 amino acid residues of human MASP3. In some embodiments, the anti-MASP3 antibody is a full-length antibody. In some embodiments, the full-length anti-MASP3 antibody is an IgG1 or IgG4 antibody. In some embodiments, the disease or disorder is selected from, for example, ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), paroxysmal nocturnal hemoglobinuria (PNH), secondary TMA after transplantation, Upshaw-Schulman syndrome, arthritis, traumatic brain injury, Aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection. In some embodiments, the individual is a human.

[0263] For example, in some embodiments, a method for treating an individual with a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a pharmaceutical composition comprising an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody), wherein the antibody comprises: a heavy chain variable domain (V H ), the V Hcomprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, or the V H A variant comprising a substitution of up to about 5 amino acids in the HC-CDRs; and a light chain variable domain (V L ), the V L comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 13, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 16, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 19, or the V L In some embodiments, the anti-MASP3 antibody is a full-length antibody. In some embodiments, the full-length anti-MASP3 antibody is an IgG1 or IgG4 antibody. In some embodiments, the disease or disorder is selected from, for example, ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), paroxysmal nocturnal hemoglobinuria (PNH), secondary TMA after transplantation, Upshaw-Schulman syndrome, arthritis, traumatic brain injury, Aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection. In some embodiments, the individual is a human.

[0264] In some embodiments, a method for treating an individual with a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a composition comprising an anti-MASP3 antibody, wherein the antibody comprises: V H , the V H comprising the amino acid sequence shown in SEQ ID NO: 22 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO: 22; and V L , the V L The invention comprises the amino acid sequence shown in SEQ ID NO: 26 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO: 26.

[0265] In some embodiments, the anti-MASP3 antibodies described herein are full-length anti-MASP3 antibodies comprising an IgG1 or IgG4 constant region. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:30. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:33.

[0266] For example, in some embodiments, a method for treating an individual with a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a pharmaceutical composition comprising an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody), wherein the antibody comprises: a heavy chain variable domain (V H ), the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 2, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 6, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 10, or the V H A variant comprising a substitution of up to about 5 amino acids in the HC-CDRs; and a light chain variable domain (V L ), the V Lcomprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 14, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 17, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 20, or the V L In some embodiments, the anti-MASP3 antibody is a full-length antibody. In some embodiments, the full-length anti-MASP3 antibody is an IgG1 or IgG4 antibody. In some embodiments, the disease or disorder is selected from, for example, ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), paroxysmal nocturnal hemoglobinuria (PNH), secondary TMA after transplantation, Upshaw-Schulman syndrome, arthritis, traumatic brain injury, Aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection. In some embodiments, the individual is a human.

[0267] In some embodiments, a method for treating an individual with a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a composition comprising an anti-MASP3 antibody, wherein the antibody comprises: V H , the V H comprising the amino acid sequence shown in SEQ ID NO: 23 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO: 23; and V L , the V LThe invention comprises the amino acid sequence shown in SEQ ID NO: 27 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO: 27.

[0268] In some embodiments, the anti-MASP3 antibodies described herein are full-length anti-MASP3 antibodies comprising an IgG1 or IgG4 constant region. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:30. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:33.

[0269] For example, in some embodiments, a method for treating an individual with a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a pharmaceutical composition comprising an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody), wherein the antibody comprises: a heavy chain variable domain (V H ), the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 3, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 7, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 11, or the V H A variant comprising a substitution of up to about 5 amino acids in the HC-CDRs; and a light chain variable domain (V L ), the V L comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 15, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 18, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 21, or the V LIn some embodiments, the anti-MASP3 antibody is a full-length antibody. In some embodiments, the full-length anti-MASP3 antibody is an IgG1 or IgG4 antibody. In some embodiments, the disease or disorder is selected from, for example, ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), paroxysmal nocturnal hemoglobinuria (PNH), secondary TMA after transplantation, Upshaw-Schulman syndrome, arthritis, traumatic brain injury, Aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection.

[0270] In some embodiments, the individual is a human.

[0271] In some embodiments, a method for treating an individual with a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a composition comprising an anti-MASP3 antibody, wherein the antibody comprises: V H , the V H comprising the amino acid sequence shown in SEQ ID NO: 24 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO: 24; and V L , the V L The invention comprises the amino acid sequence shown in SEQ ID NO: 28 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO: 28.

[0272] In some embodiments, the anti-MASP3 antibodies described herein are full-length anti-MASP3 antibodies comprising an IgG1 or IgG4 constant region. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:30. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:33.

[0273] For example, in some embodiments, a method for treating an individual with a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a pharmaceutical composition comprising an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody), wherein the antibody comprises: a heavy chain variable domain (V H ), the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12, or the V H A variant comprising a substitution of up to about 5 amino acids in the HC-CDRs; and a light chain variable domain (V L ), the V L comprising: LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 15, LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 18, and LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 21, or the V LIn some embodiments, the anti-MASP3 antibody is a full-length antibody. In some embodiments, the full-length anti-MASP3 antibody is an IgG1 or IgG4 antibody. In some embodiments, the disease or disorder is selected from, for example, ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), paroxysmal nocturnal hemoglobinuria (PNH), secondary TMA after transplantation, Upshaw-Schulman syndrome, arthritis, traumatic brain injury, Aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection. In some embodiments, the individual is a human.

[0274] In some embodiments, a method for treating an individual with a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity) is provided, comprising administering to the individual an effective amount of a composition comprising an anti-MASP3 antibody, wherein the antibody comprises: V H , the V H comprising the amino acid sequence of SEQ ID NO: 25 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence of SEQ ID NO: 25; and V L , the V L The invention comprises the amino acid sequence shown in SEQ ID NO: 29 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO: 29.

[0275] In some embodiments, the anti-MASP3 antibodies described herein are full-length anti-MASP3 antibodies comprising an IgG1 or IgG4 constant region. In some embodiments, the IgG1 is a human IgG1. In some embodiments, the IgG4 is a human IgG4. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:30. In some embodiments, the heavy chain constant region comprises or consists of the amino acid sequence SEQ ID NO:31. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:32. In some embodiments, the light chain constant region comprises or consists of the amino acid sequence SEQ ID NO:33.

[0276] In some embodiments, the individual is a mammal (e.g., a human, non-human primate, rat, mouse, cattle, horse, pig, sheep, goat, dog, cat, etc.). In some embodiments, the individual is a human. In some embodiments, the individual is a clinical patient, a clinical trial volunteer, an experimental animal, etc. In some embodiments, the individual is less than 60 years old (including, for example, less than 50, 40, 30, 25, 20, 15 or 10 years old). In some embodiments, the individual is older than 60 years old (including, for example, older than 70, 80, 90 or 100 years old). In some embodiments, the individual is diagnosed with or is susceptible to one or more diseases or conditions described herein from a genetic perspective (e.g., autoimmune diseases, transplant-related diseases, inflammatory diseases, blood diseases, coagulation diseases, angiogenesis-dependent diseases and / or viral infectivity). In some embodiments, the individual has one or more risk factors associated with one or more diseases or conditions described herein.

[0277] In some embodiments, the present application provides a method of delivering an anti-MASP3 antibody (e.g., any anti-MASP3 antibody described herein, e.g., an isolated anti-MASP3 antibody) to a cell expressing MASP3 in an individual, the method comprising administering to the individual a composition comprising the anti-MASP3 antibody.

[0278] Many diagnostic methods and clinical descriptions of autoimmune diseases, transplantation-related diseases, inflammatory diseases, hematological diseases, coagulopathy, angiogenesis-dependent diseases and / or viral infectivity or any other disease associated with complement activation are known in the art. Such methods include, but are not limited to, immunohistochemistry, PCR, and fluorescence in situ hybridization (FISH).

[0279] In some embodiments, the anti-MASP3 antibodies (e.g., full-length anti-MASP3 antibodies) and / or compositions described herein are used in combination with a second, third, or fourth agent (including, for example, an immunosuppressant, an anti-inflammatory drug, an analgesic, other complement inhibitors, or angiogenic inhibitors) to treat diseases associated with complement activation.

[0280] Dosage and method of administration of anti-MASP3 antibodies

[0281] The dosage of an anti-MASP3 antibody (e.g., isolated anti-MASP3 antibody) composition administered to an individual (e.g., a human) may vary depending on the specific composition, mode of administration, and type of disease being treated. In some embodiments, the amount of a composition (e.g., a composition comprising an anti-MASP3 antibody) is effective to produce an objective response (e.g., a partial response or a complete response) in the treatment of autoimmune diseases, transplant-related diseases, inflammatory diseases, blood diseases, coagulation diseases, angiogenesis-dependent diseases, and / or viral infections. In some embodiments, the amount of the anti-MASP3 antibody composition is sufficient to produce a complete response in an individual. In some embodiments, the amount of the anti-MASP3 antibody composition is sufficient to produce a partial response in an individual. In some embodiments, the dosage of the anti-MASP3 antibody composition administered (e.g., when administered alone) is sufficient to produce an overall response rate of greater than 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 64%, 65%, 70%, 75%, 80%, 85%, or 90% in a population of individuals treated with the anti-MASP3 antibody composition. An individual's response to the treatment methods described herein can be determined, for example, by changes in components of the complement system.

[0282] In some embodiments, the amount of the composition (e.g., a composition comprising an isolated anti-MASP3 antibody) is sufficient to prolong progression-free survival in an individual. In some embodiments, the amount of the composition is sufficient to prolong overall survival in an individual. In some embodiments, the amount of the composition (e.g., when administered alone) is sufficient to produce a clinical benefit greater than 50%, 60%, 70%, or 77% in a population of individuals treated with an anti-MASP3 antibody composition.

[0283] In some embodiments, the amount of a composition (e.g., a composition comprising an isolated anti-MASP3 antibody), used alone or in combination with a second, third, and / or fourth agent, is an amount sufficient to control symptoms and reduce the risk of exacerbations compared to the corresponding activity in other subjects not receiving treatment before treatment. The magnitude of the therapeutic effect can be measured using standard methods, such as in vitro assays of purified enzymes, cell-based assays, animal models, or human trials.

[0284] In some embodiments, the amount of the anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody) in the composition is below a level that causes a toxic effect (i.e., an effect above a clinically acceptable toxicity level) when the composition is administered to a subject, or is at a level at which potential side effects are manageable or tolerable.

[0285] In some embodiments, following the same dosing regimen, the amount of the composition is close to the maximum tolerated dose (MTD) of the composition. In some embodiments, the amount of the composition is higher than 80%, 90%, 95% or 98% of the MTD.

[0286] In some embodiments, the amount of anti-MASP3 antibody (eg, full-length anti-MASP3 antibody) in the composition is in the range of 0.001 μg to 1000 μg.

[0287] In any of the above embodiments, the effective amount of the anti-MASP3 antibody (eg, full-length anti-MASP3 antibody) in the composition is in the range of 0.1 μg / kg to 100 mg / kg, calculated on a body weight basis.

[0288] The anti-MASP3 antibody composition can be administered to an individual (e.g., a human) by a variety of routes, including, for example, intravenous, intraarterial, intraperitoneal, intrapulmonary, oral, inhaled, intravascular, intramuscular, intratracheal, subcutaneous, intraocular, intrathecal, mucosal, or transdermal administration. In some embodiments, a sustained-release formulation of the composition is used. In some embodiments, the composition is administered intravenously. In some embodiments, the composition is administered arterially. In some embodiments, the composition is administered intraperitoneally. In some embodiments, the composition is administered intrahepatically. In some embodiments, the composition is administered by hepatic artery infusion. In some embodiments, the composition is administered to a site away from the first lesion.

[0289] Products and kits

[0290] In some embodiments of the present application, a product is provided, the product comprising a substance that can be used to treat a disease associated with complement activation (e.g., autoimmune disease, transplantation-related disease, inflammatory disease, blood disease, coagulation disease, angiogenesis-dependent disease and / or viral infectivity), or for delivering an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody) to cells expressing MASP3 on the surface. The product may include a container and a label or package insert on or attached to the container. Suitable containers include, for example, bottles, vials, syringes, etc. The container may be made of a variety of materials, such as glass or plastic. Generally, the container contains a composition that can effectively treat the disease or condition described herein and has a sterile port (e.g., the container may be an intravenous infusion bag or a vial with a hypodermic injection needle that can pierce the lid). At least one active substance in the composition is the anti-MASP3 antibody described in the present application. The label or package insert indicates the specific condition that the composition can be used to treat. The label or package insert further includes instructions for administering the anti-MASP3 antibody composition to a patient. Articles of manufacture and kits comprising combination therapies are within the scope of this disclosure.

[0291] Package inserts refer to instructions typically included in commercial packages of therapeutic products that contain information about indications, usage, dosage, administration, contraindications, and / or warnings related to the use of these therapeutic products. In some embodiments, the package insert indicates that the composition can be used to treat diseases associated with complement activation (e.g., autoimmune diseases, transplantation-related diseases, inflammatory diseases, blood diseases, coagulation diseases, angiogenesis-dependent diseases, and / or viral infectivity). In some embodiments, the package insert indicates that the composition can be used to treat the following diseases, including ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinemia glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), paroxysmal nocturnal hemoglobinuria (PNH), secondary TMA after transplantation, Upshaw-Schulman syndrome, arthritis, Traumatic brain injury, aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection.

[0292] In addition, the article of manufacture may further include a second container comprising a pharmaceutically acceptable buffer, such as bacteriostatic water for injection (BWFI), phosphate buffered saline, Ringer's solution or dextrose solution. Other materials required from a commercial and user perspective may also be included, including other buffers, diluents, filters, needles and syringes.

[0293] Also provided are kits that can be used for various purposes, such as for treating diseases associated with complement activation (e.g., autoimmune diseases, transplantation-related diseases, inflammatory diseases, blood diseases, coagulation diseases, angiogenesis-dependent diseases and / or viral infectivity), or for delivering anti-MASP3 antibodies (e.g., full-length anti-MASP3 antibodies) to cells expressing MASP3 on their surface, optionally in combination with a preparation. The kit of the present application includes one or more containers, which contain an anti-MASP3 antibody composition (or a single dose form and / or preparation), and in some embodiments, further contains another agent (e.g., an agent described herein) and / or instructions for use consistent with any of the methods described herein. The kit may further include a description for selecting a suitable treatment subject. The instructions for use included in the kit of the present application are generally written instructions on a label or package insert (e.g., a paper sheet included in the kit), and machine-readable instructions (e.g., instructions on a magnetic or optical storage disc) are also acceptable.

[0294] For example, in some embodiments, the kit includes a composition comprising an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody). In some embodiments, the kit includes: a) a composition comprising any of the anti-MASP3 antibodies described herein, and b) at least one effective amount of other agent that can enhance the effect of the anti-MASP3 antibody (e.g., therapeutic effect, detection effect). In some embodiments, the kit includes: a) a composition comprising any of the anti-MASP3 antibodies described herein, and b) instructions for administering the anti-MASP3 antibody composition to an individual for treating a disease associated with complement activation (e.g., an autoimmune disease, a transplant-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity). In some embodiments, the kit includes: a) a composition comprising any of the anti-MASP3 antibodies described herein, and b) at least one other agent in an effective amount that can enhance the effect of the anti-MASP3 antibody (e.g., therapeutic effect, detection effect), and c) instructions for administering the anti-MASP3 antibody composition and other substances to an individual for treating a disease associated with complement activation (e.g., autoimmune disease, transplantation-related disease, inflammatory disease, blood disease, coagulation disease, angiogenesis-dependent disease, and / or viral infectivity). The anti-MASP3 antibody and other substances may be present in separate containers or in the same container. For example, the kit may include one specific composition or two or more compositions, wherein one composition includes an anti-MASP3 antibody and another composition includes another agent.

[0295] In some embodiments, the kit comprises a (or a set of) nucleic acids encoding an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody). In some embodiments, the kit comprises: a) a (or a set of) nucleic acids encoding an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody), and b) a host cell expressing the nucleic acid (or set of nucleic acids). In some embodiments, the kit comprises: a) a (or a set of) nucleic acids encoding an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody), and b) instructions for use for: i) expressing the anti-MASP3 antibody in a host cell, ii) preparing a composition comprising the anti-MASP3 antibody, and iii) administering a composition comprising the anti-MASP3 antibody to a subject to treat a disease associated with complement activation (e.g., an autoimmune disease, a transplant-related disease, an inflammatory disease, a blood disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity). In some embodiments, the kit comprises: a) a nucleic acid (or a set of nucleic acids) encoding an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody), b) a host cell expressing the nucleic acid (or a set of nucleic acids), and c) instructions for: i) expressing the anti-MASP3 antibody in the host cell, ii) preparing a composition comprising the anti-MASP3 antibody, and iii) administering the composition comprising the anti-MASP3 antibody to a subject to treat a disease associated with complement activation (e.g., an autoimmune disease, a transplantation-related disease, an inflammatory disease, a hematological disease, a coagulopathy, an angiogenesis-dependent disease, and / or a viral infectivity).

[0296] The kit described in the present application is packaged in a suitable form. Suitable packaging includes, but is not limited to, vials, bottles, jars, flexible packages (e.g., sealed polyester film or plastic bags), etc. The kit can optionally provide other components, such as buffer and instruction information. Therefore, the present application also provides products, which include vials, bottles, jars, flexible packages (e.g., sealed polyester film or plastic bags), etc.

[0297] Instructions for use of anti-MASP3 antibody compositions generally include information such as dosage, dosing cycle and route of administration. The container may be a unit dose, a bulk package (e.g., a multiple dose package) or a subunit dose. For example, a kit is provided that contains a sufficient dose of an anti-MASP3 antibody (e.g., a full-length anti-MASP3 antibody) as described herein to provide long-term effective treatment of an individual, such as one week, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 2 weeks, 3 weeks, 4 weeks, 6 weeks, 8 weeks, 3 months, 4 months, 5 months, 7 months, 8 months, 9 months or longer. The kit may also contain multiple unit doses of the anti-MASP3 antibody, the pharmaceutical composition and instructions for use, and is packaged in an amount sufficient for storage and use in a pharmacy, such as a hospital pharmacy or a compounding pharmacy.

[0298] Those skilled in the art will recognize that several embodiments are possible within the scope and purpose of the present application. The present application will now be described in more detail by reference to the following non-limiting examples. The following examples further illustrate the present application, but should not be construed as limiting its scope in any way. DETAILED DESCRIPTION

[0299] In the following disclosed embodiments, the following abbreviations are used: MASP2 (Mannan-Binding Lectin Associated Serine Protease-2); MASP3 (Mannan-Binding Lectin Associated Serine Protease-3); MBL (Mannan-Binding Lectin).

[0300] Example 1: Preparation of recombinant protein

[0301] 1.1 Preparation of recombinant full-length MASP3 protein and derived peptides

[0302] The cDNA encoding human MASP3 (GenBank ID No.: 5648), monkey MASP3 (GenBank ID No.: 708206) or mouse MASP3 (GenBank ID No.: 17174) was constructed into a eukaryotic expression vector by subcloning. The cDNA encoding the CCP2-SP domain or SP domain of human MASP3 was constructed into a eukaryotic expression vector by subcloning. His tags and / or Avi tags and / or other tags commonly used by those skilled in the art were added to the ends of the cDNAs of the above proteins to construct plasmids encoding human, monkey or mouse MASP3 proteins and MASP3-derived polypeptides. The above plasmids were transfected into 293F cells for expression to produce full-length MASP3 fusion proteins and MASP3-derived polypeptides, such as human MASP3-His, human MASP3-Avi-His, monkey MASP3-His, mouse MASP3-His, human MASP3 CCP2-SP-His, and human MASP3 SP-His, wherein "His" represents a His tag and "Avi" represents an avidin tag.

[0303] According to the operating instructions of the nickel column (Ni), the recombinant protein with the His tag was purified and the biotinylation ligase B0101A (GeneCopoeia) was used to successfully prepare the biotinylated human MASP3-Avi-His recombinant protein, which was named human MASP3-Bavih.

[0304] 1.2 Preparation of recombinant human pre-factor D (Factor D)

[0305] The cDNA encoding human pre-D factor (GenBank ID: 1675) was constructed into a prokaryotic expression vector by subcloning. A His tag / or other tags commonly used by those skilled in the art were added to the cDNA end of the above protein to construct a tag plasmid encoding human pre-D factor. The above tag plasmid was transformed into Escherichia coli for expression to produce a fusion protein of pre-D factor (pFD), such as pFD-His, wherein "His" represents a His tag. According to the manufacturer's operating instructions, a nickel column (Ni) was used to purify the recombinant protein with a His tag.

[0306] Example 2: Screening of anti-MASP3 single-chain antibodies (scFv)

[0307] 2.1 Construction of scFv antibody phage display library:

[0308] Human MASP3 CCP2-SP-His or human MASP3 SP-His was used as an antigen and immunized with equal parts (v / v) of adjuvant to 6-8 week old BALB / c mice or MASP1 / 3 knockout mice (purchased from Shanghai Model Organisms, NM-KO-200353). The serum of the immunized mice was taken and the titer of antigen-specific IgG in the serum of the immunized mice was detected by ELISA. After several rounds of immunization, the spleen of the mice was used to establish a phage display library. In brief, the spleen of the immunized mice was taken, RNA was extracted, and cDNA was obtained by reverse transcription. V H and V K Specific primers amplify V H and V K The fragment was purified by gel recovery and ligated to V H and V K , scFv was constructed and cloned into the phage display plasmid pDAN3X. Subsequently, the plasmid was electroporated into Escherichia coli TG1, and the phage was used to infect Escherichia coli TG1 to obtain the scFv antibody phage display library.

[0309] 2.2 Screening of anti-MASP3 single-chain antibody (scFv):

[0310] In multiple rounds of panning, two screening strategies were used to isolate phages that bind human MASP3 from the phage display library.

[0311] Solid phase screening: The human MASP3-His or MASP3 SP-His antigen prepared in Example 1 was coated on an ELISA plate, and the constructed phage display library was added thereto at an input amount of 4×10 11 pfu / well, incubated at 37°C for 2 hours, screened positive phages that bind to the antigen using anti-M13 antibody (Sino Biological, 11973-MM05T-H), and eluted the positive phages using alkaline elution solution. After multiple rounds of screening, the positive phages that bind to the antigen were enriched. The single positive clones were analyzed by further ELISA testing to obtain a series of positive scFv antibodies.

[0312] Liquid phase screening: The human MASP3-Bavih antigen (10 μg) prepared in Example 1 was mixed with the constructed phage display library (2×10 12 pfu) and incubated at 37°C for 1 hour. The mixture after incubation was added to the blocked streptavidin-coated magnetic beads to screen out the positive phages binding to the antigen, and the positive phages were eluted with alkaline elution solution. After multiple rounds of screening, the positive phages binding to the antigen were enriched. The single positive clones were analyzed by further ELISA detection to obtain a series of positive scFv antibodies.

[0313] Example 3: Preparation and Characterization of Full-Length Anti-MASP3 Chimeric Antibodies

[0314] 3.1 Preparation of chimeric antibodies against full-length MASP3

[0315] The positive scFv enriched after multiple rounds of screening were sequenced and V was amplified from the phage display vector pDAN3X. L and V H , respectively constructed into the eukaryotic expression vectors pTTa1-L (containing the κ constant region) and pTTa1-H4 (containing the IgG4 heavy chain constant region). The plasmid expressing the light chain and the plasmid expressing the heavy chain were co-transfected into 293F cells, cultured at 37°C, 8% CO2, and 120rpm for 5 days, and the culture fluid was purified using a ProteinA affinity chromatography column. In brief, first, 6 column volumes of 50mM PBS buffer (containing 0.15M NaCl, pH7.2) were used to equilibrate the protein A column at a flow rate of 150cm / h. The culture supernatant (adjusted to pH 7.2) flowed through the column at a flow rate of 150cm / h. After further balancing the column, 50mM sodium citrate buffer (pH3.5) was used for elution, the eluate was collected, and the pH value was adjusted to neutral. The IgG solution was replaced in PBS buffer using a desalting column, and the IgG concentration was determined after ultrafiltration and concentration.

[0316] 3.2 Affinity of anti-MASP3 chimeric antibodies

[0317] The purified monoclonal antibody was subjected to a binding test with MASP3, which was used to identify the binding activity of anti-MASP3 antibodies. Briefly, a 96-well plate was coated with human MASP3-His antigen at 0.1 μg / well at 4°C overnight. The plate was blocked with 5% milk at 37°C for 1 hour and washed 6 times with PBST solution. Each sample was first diluted to 10 μg / ml and then serially diluted at a ratio of 1:8. The serially diluted samples were added to a 96-well plate, 100 μl per well, and incubated at 37°C for 1 hour. The plate was then washed 6 times with PBST solution. 100 μl of goat anti-human IgG-HRP (1:10000 dilution, Sigma, A8667) was added to each well and incubated at 37°C for 1 hour. The plate was washed 6 times with PBST solution. 100 μl of TMB was added to each well and incubated at 37°C for 10-20 minutes. The reaction was terminated with 2M H2SO4. The absorbance at 450 nm (OD450) was read using a microplate reader, and the binding curve was generated using PRISM to calculate the EC 50 The affinity of each anti-MASP3 antibody to the antigen was analyzed by using the value.

[0318] The results are shown in Table 11. The screened anti-MASP3 chimeric antibodies M3-K3, M3-K4, M3-K51 and M3-K52 can all bind to the human MASP3 antigen, and their affinity to the human MASP3 antigen is significantly better than that of the control antibody OMS906.

[0319] Table 11: Binding ability of anti-MASP3 antibodies to human MASP3

[0320] Antibody Name <![CDATA[EC 50 (nM)]]> M3-K3 0.07 M3-K4 0.13 M3-K51 0.22 M3-K52 0.16 OMS906 1.12

[0321] 3.3 Detection of the inhibition of MASP3 enzyme activity by anti-MASP3 chimeric antibodies:

[0322] MASP3 is a serine protease that has the ability to hydrolyze specific amino acids. 2+ Under the conditions of 380nm excitation light / 460nm emission light, the fluorescence values ​​at different time periods are detected, and the ability of anti-MASP3 antibodies to inhibit MASP3 enzyme activity is reflected by this.

[0323] Anti-MASP3 antibody was diluted to 2000 μg / ml with reaction buffer (containing 25 mM Tris-base, 10 mM CaCl2, and 0.15 M NaCl), and then gradient diluted at a ratio of 1:5 for use. Different concentrations of anti-MASP3 antibody were incubated with human MASP3-His (final concentration of 0.25 μM) at room temperature for 15 min. The fluorescent tripeptide substrate Boc-Val-Pro-Arg-AMC (R&D system, ES011) with a final concentration of 0.1 mM was added to the above system, mixed and placed in a 37°C microplate reader, and the fluorescence intensity (RFU) under the conditions of excitation light 380 nm / emission light 460 nm was detected every 5 min for a total of 60 min. Inhibition curves were generated by PRISM to calculate IC 50 value.

[0324] The results are shown in Table 12. The anti-MASP3 chimeric antibodies M3-K3, M3-K4, M3-K51 and M3-K52 can inhibit the enzymatic activity of MASP3, and their inhibitory activity is significantly better than that of the control antibody OMS906.

[0325] Table 12: Anti-MASP3 antibodies inhibit MASP3 enzymatic activity

[0326] Antibody Name <![CDATA[IC 50 (nM)]]> M3-K3 34.27 M3-K4 38.65 M3-K51 45.76 M3-K52 25.89 OMS906 199.75

[0327] 3.4 Detection of anti-MASP3 chimeric antibodies inhibiting the activity of the alternative complement pathway:

[0328] In the alternative complement pathway, the serine protease activity of MASP3 can activate complement pro-factor D (pFD) in the blood into active complement factor D (FD). FD further cleaves complement factor B (FB) into Bb. C3b formed by hydrolysis of Bb and C3 forms the alternative pathway C3 convertase (C3bBb). C3 convertase is one of the important central regulatory molecules in the complement system. It cleaves the complement molecule C3 to form two highly pro-inflammatory molecules: the anaphylatoxin C3a and the regulatory molecule C3b. C3b further combines with the alternative pathway C3 convertase (C3bBb) to form C5 convertase (C3bBb3b). C5 convertase is another important central regulatory molecule in the complement system. Its hydrolase activity cleaves C5 to form anaphylatoxins C5a and C5b. Finally, C5b and C6-9 form the biological effector molecule of complement - the membrane attack complex MAC (C5b-9).

[0329] Unsensitized rabbit or guinea pig red blood cells can activate the complement alternative pathway in human serum. After complement activation, a series of protein cascade reactions occur, which eventually lead to rabbit cell lysis. The addition of anti-MASP3 antibodies can inhibit the hemolysis mediated by the alternative pathway. The absorbance value (OD415) at 415nm is detected by an ELISA reader, and the anti-MASP3 antibody hemolysis activity is calculated based on this. In addition, ethylene glycol diaminotetraacetic acid (EGTA) is added to the reaction system, which can react with Ca in plasma. 2+ Chelated, but with Mg 2+ The binding ability is very weak, so adding EGTA can block the classical pathway to eliminate the influence of the classical pathway.

[0330] First, HBSS-Mg 2+ -EGTA buffer (containing 5mM MgCl2·6H2O and 10mM EGTA) was used to dilute the anti-MASP3 antibody to 900μg / ml, and then the antibody was diluted in a gradient at a ratio of 1:8 for later use. At room temperature, different concentrations of anti-MASP3 antibodies (M3-K3 and M3-K52 were used as examples) were incubated with human plasma depleted of factor D for 15min, and the pre-factor D prepared in Example 1 was added (final concentration was 2.5μg / ml). Fresh rabbit red blood cells or guinea pig red blood cells were washed three times with HBSS buffer (containing 0.1% gelatin) and washed with HBSS-Mg 2+ -EGTA buffer was used to dilute the washed red blood cells. Add the diluted red blood cells to the above system. Incubate at 37°C for 45 minutes, mix again and continue incubation for 20 minutes. After incubation, add 80 μl of pre-cooled stop buffer (containing 10 mM EDTA, 1× HBSS buffer, pH 7.4) to each reaction well, and centrifuge at 4°C, 1200g for 5 minutes. Take 100 μl of supernatant to a 96-well flat-bottom plate and measure OD415. Generate inhibition curves using PRISM and calculate IC 50 value.

[0331] The results are shown in Table 13. The anti-MASP3 chimeric antibodies M3-K3 and M3-K52 were both able to inhibit the hemolytic reaction mediated by activation of the alternative complement pathway, and their inhibitory activity was significantly better than that of the control antibody OMS906.

[0332] Table 13: Anti-MASP3 Antibodies Inhibit Hemolytic Activity

[0333] Antibody Name <![CDATA[IC 50 (nM)]]> M3-K3 1.94 M3-K52 4.67 OMS906 13.02

Claims

1. An isolated antibody that specifically recognizes MASP3, comprising: (i)V H , the V H comprising: HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and V L , the V L It comprises: LC-CDR1, which comprises the amino acid sequence of SEQ ID NO:13, LC-CDR2, which comprises the amino acid sequence of SEQ ID NO:16, and LC-CDR3, which comprises the amino acid sequence of SEQ ID NO:

19.

2. The isolated antibody that specifically recognizes MASP3 according to claim 1, comprising: (i)V H , which comprises the amino acid sequence shown in SEQ ID NO:22 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO:22; and V L , which comprises the amino acid sequence shown in SEQ ID NO:26 or a variant thereof, wherein the variant has at least about 80% sequence identity with the amino acid sequence shown in SEQ ID NO:

26.

3. The isolated antibody that specifically recognizes MASP3 according to any one of claims 1-2, wherein the antibody comprises an Fc fragment.

4. The isolated antibody that specifically recognizes MASP3 according to claim 3, wherein the antibody is a full-length IgG antibody.

5. The isolated antibody that specifically recognizes MASP3 according to claim 4, wherein the antibody is a full-length IgG1, IgG2, IgG3 or IgG4 antibody.

6. The isolated antibody that specifically recognizes MASP3 according to any one of claims 1 to 5, wherein the antibody is a chimeric, humanized, or fully human antibody.

7. The isolated antibody that specifically recognizes MASP3 according to any one of claims 1 to 2 is an antigen-binding fragment, wherein the antigen-binding fragment is selected from the group consisting of Fab, Fab', F(ab)'2, Fab'-SH, single-chain antibody (scFv), Fv fragment, dAb, Fd, nanobody, diabody and linear antibody.

8. A nucleic acid molecule encoding the antibody that specifically recognizes MASP3 according to any one of claims 1 to 7.

9. A vector comprising the nucleic acid molecule of claim 8.

10. An isolated host cell comprising the antibody that specifically recognizes MASP3 according to any one of claims 1 to 7, the nucleic acid molecule according to claim 8, or the vector according to claim 9.

11. A method for preparing an antibody that specifically recognizes MASP3, comprising: a) culturing the host cell of claim 10 under conditions effective to express an antibody that specifically recognizes MASP3; and b) Obtaining the expressed antibody that specifically recognizes MASP3 from the host cells.

12. A pharmaceutical composition comprising the antibody that specifically recognizes MASP3 according to any one of claims 1 to 7, the nucleic acid molecule according to claim 8, the vector according to claim 9, the isolated host cell according to claim 10, or the antibody prepared by the method according to claim 11, and a pharmaceutically acceptable carrier.

13. Use of the antibody of any one of claims 1 to 7, the nucleic acid molecule of claim 8, the vector of claim 9, the isolated host cell of claim 10, the antibody prepared by the method of claim 11, or the pharmaceutical composition of claim 12 in the preparation of a medicament for treating a disease or condition in an individual in need thereof.

14. The use according to claim 13, wherein the disease or disorder is an autoimmune disease associated with complement activation, a transplantation-related disease, an inflammatory disease, a blood disease, a coagulation disease, an angiogenesis-dependent disease and / or a viral infectious disease.

15. The method of claim 14, wherein the disease or condition is selected from the group consisting of ischemia-reperfusion injury, atherosclerosis, mesangial proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, acute post-infectious glomerulonephritis, cryoglobulinaemic glomerulonephritis, lupus nephritis, systemic lupus erythematosus (SLE), Henoch-Schönlein purpura nephritis, IgA nephropathy, ischemic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), paroxysmal nocturnal hemoglobinuria (PNH), secondary TMA after transplantation, Upshaw-Schulman syndrome, arthritis, trauma The following are some of the following: acute brain injury, aspiration pneumonia, neuromyelitis optica, multiple sclerosis, amyotrophic lateral sclerosis (ALS), chronic obstructive pulmonary disease (COPD), C3 glomerulopathy, transplant rejection, graft-versus-host disease (GVHD), sepsis, systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), ANCA vasculitis, antiphospholipid syndrome, myasthenia gravis, Degos disease, disseminated intravascular coagulation (DIC), angiogenesis-dependent cancers, age-related macular degeneration, retinopathy, proliferative diabetes, vitreous hemorrhage secondary to retinopathy, neovascular glaucoma, corneal neovascularization, retinopathy of prematurity, and respiratory distress syndrome or pneumonia caused by coronavirus infection.

16. The use according to claim 15, wherein the coronavirus is SARS-CoV, MERS-CoV and / or SARS-CoV-2.

17. The use according to any one of claims 14 to 16, wherein the medicament is administered in combination with another pharmaceutical agent.

18. The use according to claim 17, wherein the other agent is selected from immunosuppressants, anti-inflammatory drugs, analgesics, other complement inhibitors or vascular inhibitors.

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