APJ antibody and its fusion protein with ELABELA, pharmaceutical compositions and uses thereof

Abstract

The present invention provides an APJ antibody and its fusion protein with Elabela, as well as pharmaceutical compositions and uses thereof. Provided herein are apelin receptor (APJ) antibodies and their fusion proteins with Elabela. Also provided herein are pharmaceutical compositions of the fusion protein having an APJ antibody and Elabela, and uses thereof in the treatment, prevention, or amelioration of pulmonary arterial hypertension, one or more symptoms of pulmonary hypertension, or one or more symptoms of heart failure. [Selection diagram] None

Description

[Technical field]

[0001] Provided herein are Apelin Receptor (APJ) antibodies and their fusion proteins with Elabela. Also provided herein are pharmaceutical compositions of fusion proteins with APJ antibodies and Elabela and their use in treating, preventing or ameliorating pulmonary arterial hypertension, one or more symptoms of pulmonary hypertension or one or more symptoms of heart failure. [Background technology]

[0002] APJ has seven transmembrane units and 308 amino acids, and belongs to the family of G protein-coupled receptors (GPCRs). The vasoactive peptide apelin is the earliest endogenous ligand discovered for the APJ receptor. Apelin and APJ are widely distributed in the human central nervous system and various peripheral tissues such as the lung, heart, and chest (Non-Patent Document 1; Non-Patent Document 2), especially in cardiovascular endothelial cells and cardiac tissues (Non-Patent Document 3). Several studies have shown that the apelin / APJ signaling system may enhance myocardial contractility, reduce blood pressure, promote neovascularization, regulate immune response and release of pituitary-related hormones, regulate insulin secretion, etc., and may be involved in the pathophysiological events of diabetic vasculopathy, heart failure, atrial fibrillation, and ischemia-reperfusion injury.

[0003] Elabela is another endogenous ligand of the APJ receptor that has been discovered in recent years and has attracted much attention (Non-Patent Document 4; Non-Patent Document 5). Elabela is encoded by three exons on human chromosome 4 and was previously thought to be a non-coding RNA. However, studies have found that Elabela has a conserved ORF that encodes a 54-amino acid protein (its mature form consists of only 32 amino acids). The Elabela / APJ signaling pathway has been shown to play a crucial role in the development of the embryonic heart and vasculature. Studies have confirmed that Elabela and Elabela mutants can activate the Gαi1 and β-arrestin2 signaling pathways of the APJ receptor. Furthermore, mutations at the C-terminus of the Elabela polypeptide can induce a preference for the APJ receptor signaling pathway (Non-Patent Document 6). The preference for the receptor signaling pathway provides an important direction for new drug development (Non-Patent Document 7). By using isolated perfused hearts and in vivo hemodynamic and echocardiographic measurements, it was found that Elabela or Elabela mutants could reduce arterial pressure and exert a positive inotropic effect on the heart (Non-Patent Document 8; Non-Patent Document 6). Other studies also found that Elabela content in patients with diabetic nephropathy was negatively correlated with the microalbuminuria / creatinine ratio (ACR) (Non-Patent Document 9).

[0004] Fusion of Elabela with APJ antibody can significantly extend the half-life of Elabela and retain the biological activity of the Elabela molecule. At the same time, the fusion protein of APJ antibody and Elabela has the molecular targeting provided by the antibody and plays a role in the treatment of one or more diseases of pulmonary arterial hypertension (PAH), pulmonary hypertension (PH), type 2 diabetes (T2D) and its related metabolic syndrome, and heart failure, which helps to improve the druggability of the Elabela fusion protein. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 6,846,634 [Patent Document 2] U.S. Patent No. 6,696,245 [Patent Document 3] US Patent Application Publication No. 2005 / 0202512 [Patent Document 4] US Patent Application Publication No. 2004 / 0202995 [Patent Document 5] US Patent Application Publication No. 2004 / 0038291 [Patent Document 6] US Patent Application Publication No. 2004 / 0009507 [Patent Document 7] US Patent Application Publication No. 2003 / 0039958 [Patent Document 8] U.S. Patent No. 6,703,199 [Patent Document 9] US Patent Application Publication No. 2005 / 0238646 [Patent Document 10] U.S. Pat. No. 4,946,778 [Patent Document 11] U.S. Pat. No. 4,331,647 [Patent Document 12] U.S. Pat. No. 4,518,584 [Patent Document 13] U.S. Pat. No. 4,737,462 [Patent Document 14] U.S. Pat. No. 5,011,912 [Patent Document 15] PCT Application International Publication No. 93 / 10151 Pamphlet [Patent Document 16] U.S. Pat. No. 5,457,035 [Patent Document 17] U.S. Pat. No. 4,751,180 [Patent Document 18] U.S. Pat. No. 4,935,233 [Patent Document 19] Pamphlet of International Publication of PCT Application No. 94 / 10308 [Patent Document 20] Specification of U.S. Patent No. 4,640,835 [Patent Document 21] Specification of U.S. Patent No. 4,496,689 [Patent Document 22] Specification of U.S. Patent No. 4,301,144 [Patent Document 23] Specification of U.S. Patent No. 4,670,417 [Patent Document 24] Specification of U.S. Patent No. 4,791,192 [Patent Document 25] Specification of U.S. Patent No. 4,179,337 [Patent Document 26] Specification of U.S. Patent No. 6,133,426 [Patent Document 27] Specification of U.S. Patent No. 6,210,924 [Non-Patent Document]

[0006] [Non-Patent Document 1] Kawamata et al., 2001, Biochem. Biophys. Acta. 1538:162 - 71 [Non-Patent Document 2] Medhurst et al., 2003, J. Neurochem. 84:1162 - 72 [Non-Patent Document 3] Kleiz et al., 2005, Regul. Pept. 126:233 - 40 [Non-Patent Document 4] Chng et al., 2013, Dev. Cell 27:672 - 680; [Non-Patent Document 5] Pauli et al., 2014, Science 343:1248636 [Non-Patent Document 6] Murza et al., 2016, J Med Chem. 59:2962 - 72 [Non-Patent Document 7] Bologna et al.,2017,Biomol.Ther.25:12-25 [Non-licensed document 8] Yang et al.,2017,Circulation 135:1160-1173

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[0007] Provided herein are antibodies that specifically bind to APJ.

[0008] An antibody that specifically binds to APJ comprising one, two, three, four, five or six amino acid sequences, each amino acid sequence independently being any of the amino acid sequences listed below: a. Light chain CDR1 amino acid sequences: SEQ ID NO:1, SEQ ID NO:4, SEQ ID NO:7, and SEQ ID NO:10; b. Light chain CDR2 amino acid sequences: SEQ ID NO:2, SEQ ID NO:5, and SEQ ID NO:8; c. Light chain CDR3 amino acid sequences: SEQ ID NO:3, SEQ ID NO:6, SEQ ID NO:9, and SEQ ID NO:11; d. Heavy chain CDR1 amino acid sequences: SEQ ID NO:12, SEQ ID NO:15, and SEQ ID NO:18; e. Heavy chain CDR2 amino acid sequences: SEQ ID NO:13, SEQ ID NO:16, SEQ ID NO:19, and SEQ ID NO:21; and f. Heavy chain CDR3 amino acid sequences: SEQ ID NO:14, SEQ ID NO:17, SEQ ID NO:20, and SEQ ID NO:22 Provided herein is an antibody selected from:

[0009] Provided herein is an Elabela fusion protein comprising an antibody that specifically binds to APJ and a peptide linker sequence (linker) of one, two, three, four, five, six, seven or eight Elabela fragments, wherein the N-terminus of the Elabela fragments, each of which is independently a forward Elabela fragment or a mutant thereof, is linked to the C-terminus of the heavy or light chain of the APJ antibody through the peptide linker sequence (linker); or the C-terminus of the Elabela fragments, each of which is independently a reverse Elabela fragment or a mutant thereof, is linked to the N-terminus of the heavy or light chain of the APJ antibody through the peptide linker sequence (linker).

[0010] Provided herein is an Elabela fusion protein comprising an APJ antibody, two Elabela fragments, and two peptide linker sequences (linkers), in which the N-terminus of the Elabela fragment is linked to the C-terminus of the light chain of the APJ antibody through a peptide linker sequence (linker): N'-R-linker-Elabela-C'; or the N-terminus of the Elabela fragment is linked to the C-terminus of the heavy chain of the APJ antibody through a peptide linker sequence (linker): N'-R-linker-Elabela-C'; where N' represents the N-terminus of the fusion protein polypeptide, C' represents the C-terminus of the fusion protein polypeptide, Elabela represents the normal Elabela fragment or a mutant thereof, R represents the amino acid sequence of the light or heavy chain of the APJ antibody, and linker represents the peptide linker sequence.

[0011] Provided herein are polynucleotides that encode the Elabela fusion proteins described herein.

[0012] Provided herein are vectors comprising a polynucleotide encoding the Elabela fusion proteins described herein.

[0013] Provided herein is a host cell line comprising one of the vectors described herein.

[0014] Provided herein are pharmaceutical compositions comprising an APJ antibody or an Elabela fusion protein and a pharma- ceutically acceptable carrier as described herein.

[0015] Provided herein is the use of an APJ antibody or Elabela fusion protein described herein in the preparation of a medicament for treating, preventing or ameliorating PAH and PAH-related diseases.

[0016] Provided herein is the use of an APJ antibody or Elabela fusion protein described herein in the preparation of a medicament for treating, preventing or ameliorating PH and PH-related disorders.

[0017] Provided herein is the use of an APJ antibody or Elabela fusion protein described herein in the preparation of a medicament for treating, preventing or ameliorating heart failure and heart failure-related diseases.

[0018] Provided herein is the use of an APJ antibody or Elabela fusion protein as described herein in the preparation of a medicament for treating, preventing or ameliorating type 2 diabetes and associated metabolic syndrome.

[0019] Provided herein is the use of an APJ antibody or Elabela fusion protein as described herein in the preparation of a medicament for simultaneously treating, preventing or ameliorating two or more of the following diseases: PAH, PH, type 2 diabetes and related metabolic syndrome or heart failure.

[0020] Provided herein is a method for treating, preventing or ameliorating one or more symptoms of PAH, the method comprising administering to a subject a therapeutically effective dose of an APJ antibody or Elabela fusion protein described herein.

[0021] Provided herein are methods for treating, preventing or ameliorating one or more symptoms of PH, comprising administering to a subject a therapeutically effective dose of an APJ antibody or Elabela fusion protein described herein.

[0022] Provided herein is a method for treating, preventing or ameliorating one or more symptoms of heart failure, the method comprising administering to a subject a therapeutically effective dose of an APJ antibody or Elabela fusion protein described herein.

[0023] Provided herein is a method for treating, preventing or ameliorating one or more symptoms of type 2 diabetes and associated metabolic syndrome, the method comprising administering to a subject a therapeutically effective dose of an APJ antibody or Elabela fusion protein described herein. [Brief description of the drawings]

[0024] [Figure 1] The results of FACS testing of specific binding of recombinant hAPJ antibodies L1H1 (including SEQ ID NO:59 and SEQ ID NO:64) and L4H4 (including SEQ ID NO:62 and SEQ ID NO:67) to hAPJ (at antibody concentrations of 500 nM or 4 nM) are shown. The gray peaks are negative controls and represent the binding curves of L1H1 or L4H4 to CHO-DHFR-. The solid peaks represent the binding curves of L1H1 (FIGS. 1A and 1B) or L4H4 (FIGS. 1C and 1D) to CHO-DHFR-hAPJ. [Diagram 2] Activation curves of reporter gene assay testing of hAPJ antibody L5H5 (comprising SEQ ID NO: 63 and SEQ ID NO: 68) and linker2-Elabela-11 (comprising SEQ ID NO: 123 and SEQ ID NO: 93) fusion protein and L5H5 and linker2-EA5 (comprising SEQ ID NO: 123 and SEQ ID NO: 94) fusion protein to activate the Elabela / APJ signaling pathway, with EC50 of 3.6 nM and 2.6 nM, respectively. [Diagram 3]Activation curves of reporter gene assay test of hAPJ antibody L5H5 and linker2-EA1 (comprising SEQ ID NO: 123 and SEQ ID NO: 103) fusion protein and L5H5 and linker2-EA2 (comprising SEQ ID NO: 123 and SEQ ID NO: 107) fusion protein to activate Elabela / APJ signaling pathway, with EC50 of 5.0 nM and 2.2 nM, respectively. [Figure 4] Activation curves of reporter gene assay testing of hAPJ antibody L5H5 and linker2-EA3 (comprising SEQ ID NO: 123 and SEQ ID NO: 109) fusion protein and L5H5 and linker2-EA4 (comprising SEQ ID NO: 123 and SEQ ID NO: 116) fusion protein to activate the Elabela / APJ signaling pathway, with EC50 of 20.3 nM and 5.4 nM, respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] definition Unless otherwise defined herein, scientific and technical terms described herein shall have the meanings understood by those of ordinary skill in the art. In general, the nomenclature and techniques related to pharmacology, biology, biochemistry, cell and tissue culture, molecular biology, immunology, microbiology, genetics and protein nucleic acid chemistry, and hybridization are those well known and commonly used in the art.

[0026] In the present application, standard one-letter or three-letter abbreviations are used to indicate polynucleotide and polypeptide sequences. When a polypeptide sequence is described, the first amino acid residue bearing an amino group (N') is at the left end and the last amino acid residue bearing a carboxyl group (C') is at the right end, such as the sequences of the Elabela fragments according to the invention and mutants thereof: SEQ ID NO:91, SEQ ID NO:92, SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:95, SEQ ID NO:96, SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:100, SEQ ID NO:101, SEQ ID NO:102, SEQ ID NO:103, SEQ ID NO:104, SEQ ID NO:105, SEQ ID NO:106, SEQ ID NO:107, SEQ ID NO:108, SEQ ID NO:109, SEQ ID NO:110, SEQ ID NO:111, SEQ ID NO:112, SEQ ID NO:113, SEQ ID NO:114, SEQ ID NO:115, SEQ ID NO:116, SEQ ID NO:117, SEQ ID NO:118, SEQ ID NO:119, SEQ ID NO:120 and SEQ ID NO:121. Reverse polypeptide sequence refers to a polypeptide sequence in which the amino acids are arranged in reverse order relative to the original, for example the reverse Elabela fragment and its mutant sequences converted from the above Elabela fragment and its mutant sequences: SEQ ID NO: 125, SEQ ID NO: 126, SEQ ID NO: 127, SEQ ID NO: 128, SEQ ID NO: 129, SEQ ID NO: 130, SEQ ID NO: 131, SEQ ID NO: 132, SEQ ID NO: 133, SEQ ID NO: 134, SEQ ID NO: 135, SEQ ID NO: 136, SEQ ID NO: 137, SEQ ID NO: 138, SEQ ID NO: 139, SEQ ID NO: 140, SEQ ID NO: 141, SEQ ID NO: 142, SEQ ID NO: 143, SEQ ID NO: 144, SEQ ID NO: 145, SEQ ID NO: 146, SEQ ID NO: 147, SEQ ID NO: 148, SEQ ID NO: 149, SEQ ID NO: 150, SEQ ID NO: 151, SEQ ID NO: 152, SEQ ID NO: 153, SEQ ID NO: 154 and SEQ ID NO: 155. The 5' end of the top strand of the single-stranded and double-stranded nucleic acid sequences is on the left and their 3' ends are on the right. A particular portion of a polypeptide may be represented by the amino acid residue number, such as amino acids 67 to 134, or by the actual residue at that position, such as Lys67 to Lys134. A particular polypeptide or polynucleotide sequence may also be represented by indicating its differences from a reference sequence.

[0027] The term "individual" refers to an animal, including, but not limited to, a primate (e.g., a human), cow, pig, sheep, goat, horse, dog, cat, rabbit, rat or mouse. The terms "individual" and "patient" are used interchangeably to refer, for example, to a mammalian individual, e.g., a human individual, and in one embodiment, to a human.

[0028] The meaning of the term "treatment" includes reducing or eliminating a disorder, disease or condition, or one or more symptoms associated with a disorder, disease or condition; or reducing or eliminating the pathology of a disorder, disease or condition.

[0029] The term "prevention" includes delaying and / or alleviating the onset of a disorder, disease or condition and / or its associated symptoms; preventing an individual from suffering from a disorder, disease or condition; or reducing an individual's risk of suffering from a disorder, disease or condition.

[0030] The term "control" refers to preventing or slowing the progression, spread, or worsening of a disease, disorder, or condition, or one or more symptoms (e.g., pain). Sometimes, an individual benefits from the beneficial effects of a prophylactic or therapeutic agent that does not result in a cure of the condition, disorder, or disease. In one embodiment, the term "control" refers to preventing or slowing the progression, spread, or worsening of osteolytic pain.

[0031] The terms "therapeutically effective dose" and "effective amount" refer to an amount of a compound or combination of compounds that, when administered, is sufficient to prevent the onset of or reduce one or more symptoms of a disorder, disease, or condition. The term "therapeutically effective dose" or "effective amount" also refers to an amount of a compound that is sufficient to elicit the biological or medical response in a biomolecule (e.g., protein, enzyme, RNA, or DNA), cell, tissue, system, animal, or human that is sought by a researcher, veterinarian, physician, or clinician.

[0032] The terms "pharmaceutically acceptable carrier", "pharmaceutically acceptable excipient", "physiologically acceptable carrier" or "physiologically acceptable excipient" refer to a pharma- ceutically acceptable material, composition or carrier, such as a liquid or solid filler, diluent, solvent or packaging material. In one embodiment, each component is "pharmaceutically acceptable": compatible with the other components of a pharmaceutical formulation, suitable for contact with human or animal tissues or organs, and presents no excessive toxicity, irritation, allergic response, immunogenicity or other problem or complication, consistent with a reasonable risk-benefit ratio.

[0033] The term "about" or "approximately" refers to an acceptable error as determined by one of ordinary skill in the art, which depends in part on how the value is measured or determined. In certain embodiments, the term "about" or "approximately" means within 1, 2, 3, or 4 standard deviations. In certain embodiments, the term "about" or "approximately" means within 50%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, or 0.05% of a given value or range.

[0034] The terms "peptide," "polypeptide," and "protein" refer to molecules comprising two or more amino acids joined together by peptide bonds. These terms encompass, for example, natural and artificial proteins and peptide analogues of protein sequences, such as muteins, variants, and fusion proteins, as well as post-translationally or covalently or non-covalently modified proteins. A peptide, polypeptide, or protein may be monomeric or polymeric.

[0035] The term "polypeptide fragment" refers to a polypeptide having an amino-terminal and / or carboxyl-terminal deletion from the corresponding full-length protein. For example, the fragment length can be at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 50, 70, 80, 90, 100, 150, or 200 amino acids in length. The fragment length can be, for example, up to 1,000, 750, 500, 250, 200, 175, 150, 125, 100, 90, 80, 70, 60, 50, 40, 30, 20, 15, 14, 13, 12, 11, or 10 amino acids. The fragment can further comprise one or more additional amino acids at either or both ends, such as an amino acid sequence from a different naturally occurring protein (e.g., an Fc or leucine zipper domain) or an artificial amino acid sequence (e.g., an artificial binding sequence).

[0036] The polypeptides of the present invention include polypeptides modified for any reason or by any means, such as (1) to reduce susceptibility to proteolysis, (2) to reduce susceptibility to oxidation, (3) to modify affinity to form protein complexes, (4) to modify binding affinity, and (5) to confer or modulate other physicochemical or functional properties. Analogs include muteins of the polypeptide. For example, single or multiple amino acid substitutions (e.g., conservative amino acid substitutions) can be made in the native sequence (e.g., outside the domains of the polypeptide that form intermolecular contacts). A "conservative amino acid substitution" is one that does not substantially change the structural features of the parent sequence (e.g., the amino acid substitution should not disrupt the helices present in the parent sequence or interfere with other secondary structural types required to confer its properties or functions to the parent sequence).

[0037] A "mutant" of a polypeptide includes an amino acid sequence that contains an insertion, deletion and / or substitution of one or more residues in the amino acid sequence compared to another polypeptide sequence. Variants of the present invention include fusion proteins.

[0038] A "derivative" of a polypeptide is a polypeptide that has been chemically modified, for example, by conjugation to other chemical moieties, such as polyethylene glycol, albumin (such as human serum albumin), phosphorylation, and glycosylation.

[0039] Unless otherwise indicated, the term "antibody" includes antibodies comprising two full-length heavy chains and two full-length light chains, as well as derivatives, variants, fragments and muteins thereof, examples of which are described below.

[0040] The term "antibody" is a protein that includes an antigen-binding portion and, optionally, a scaffold or framework portion that allows the antigen-binding portion to adopt a conformation that promotes binding of the antibody to the antigen. Examples of antibodies include complete antibodies, antibody fragments (such as the antigen-binding portion of an antibody), antibody derivatives, and antibody analogs. For example, antibodies may include alternative protein scaffolds or artificial scaffolds that include grafted CDRs or derivatives of CDRs. Scaffolds include, but are not limited to, scaffolds derived from introduced antibodies, such as those that stabilize the three-dimensional structure of antibodies, and fully synthetic scaffolds, such as for biocompatible polymers. See, for example, (Non-Patent Document 10); (Non-Patent Document 11). Additionally, antibodies may be either scaffolds, including peptide antibody mimics ("PAM") or antibody mimics that use fibrin ligands as scaffolds.

[0041] Antibodies may have structures such as those of native immunoglobulins. An "immunoglobulin" is a tetrameric molecule. In native immunoglobulins, each tetramer consists of two identical pairs of polypeptide chains, each pair having a "light" chain (about 25 kDa) and a "heavy" chain (about 50-70 kDa). The amino terminus of each chain contains a variable domain of about 100-110 amino acids that is primarily involved in antigen recognition. The carboxyl terminus of each chain defines a constant region that is primarily involved in effector effects. Human antibody light chains are classified as kappa and lambda light chains. Heavy chains are classified as μ, δ, α or ε, and have defined the same type of antigen, such as IgM, IgD, IgG, IgA and IgE. Within the light and heavy chains, the variable and constant regions are joined by a "J" region of about 12 or more amino acids, and the heavy chains also contain a "D" region of about 10 or more amino acids. (See Non-Patent Document 12). The variable regions of each light / heavy chain pair form the antibody binding site, thus an intact immunoglobulin has two binding sites.

[0042] Natural immunoglobulin chains exhibit the same basic structure of relatively conserved framework regions (FR) bounded by three hypervariable regions, also known as complementarity determining regions or CDRs. From the N-terminus to the C-terminus, light and heavy chains contain the structural domains FR1, CDR1, FR2, CDR2, FR3, CDR3 and FR4. The distribution of amino acids in all structural domains was consistent with Kabat et al. in (Non-Patent Document 13).

[0043] Unless otherwise specified, "antibody" refers to either an intact immunoglobulin or an antigen-binding portion thereof that can compete with the intact antibody for specific binding. Antigen-binding portions may be produced by recombinant DNA techniques, enzymatic or chemical cleavage of intact antibodies. Antigen-binding portions include, inter alia, Fab, Fab', F(ab)2, Fv, structural domain antibodies (dAbs), including complementarity determining regions (CDRs), single-chain antibodies (scFv), chimeric antibodies, two-chain antibodies (diabodies), three-chain antibodies (triabodies), four-chain antibodies (tetrabodies), and polypeptides that contain at least a portion of an immunoglobulin that binds to a specific antigen.

[0044] The Fab fragment is V L , V H , C L and C H1 a F(ab')2 fragment is a bivalent fragment having two Fab fragments linked by a disulfide bond at the hinge region; an Fv fragment is a monovalent fragment having a V H and V L domain; the dAb fragment has the V H Domain, V L Domain or V H Or V L The domains have antigen-binding fragments (Patent Document 1 and Patent Document 2; Patent Document 3, Patent Document 4, Patent Document 5, Patent Document 6 and Patent Document 7; Non-Patent Document 14).

[0045] Single chain antibodies (scFv) are L and V H A fusion protein in which domains are joined through a linker (e.g., a synthetic sequence of amino acid residues) to form a contiguous protein antibody, where the linker is long enough to allow the protein chain to fold back on itself to form a monovalent antigen-binding site (see, e.g., (15) and (16)).

[0046] A double-chain antibody is a bivalent antibody that contains two polypeptide chains, each of which is a V domain connected by a linker that is too short to allow pairing of the two domains on the same chain. H and V LThe double-chain antibody contains a region that allows each domain to pair with a complementary domain on another polypeptide chain (see, for example, (Non-Patent Document 17); (Non-Patent Document 18)). When the two polypeptide chains of a double-chain antibody are identical, the double-chain antibody resulting from their pairing has the same antigen-binding site. Polypeptide chains with different sequences can be used to generate double-chain antibodies with different antigen-binding sites. Similarly, three-chain and four-chain antibodies are antibodies that contain three and four polypeptide chains and form three and four antigen-binding sites that can be the same or different.

[0047] Herein, the method described by Kabat et al. in (Non-Patent Document 13) is used to identify the complementarity determining regions (CDRs) and framework regions (FRs) of a given antibody. One or more CDRs can be incorporated covalently or non-covalently into a molecule to make it an antibody. An antibody can incorporate a larger polypeptide chain into the CDRs. The CDRs can be covalently attached to another polypeptide chain or can be non-covalently incorporated into the CDRs, allowing the antibody to specifically bind to a particular antigen of interest.

[0048] An antibody may have one or more binding sites. When there is more than one binding site, the binding sites may be identical to one another or different. For example, a native human immunoglobulin usually has two identical binding sites, while a "bispecific" or "bifunctional" antibody has two different binding sites.

[0049] The term "murine antibody" includes antibodies that have one or more variable and constant regions derived from murine immunoglobulin sequences.

[0050] The term "humanized antibody" is an antibody that is created by grafting sequences of the complementarity determining regions of a mouse antibody molecule onto the framework of a human antibody variable region.

[0051] The terms "antigen-binding domain", "antigen-binding region" or "antigen-binding site" are the portions of an antibody that contain the amino acid residues that interact with an antigen and contribute to the antibody's specificity and affinity for the antigen. For antibodies that specifically bind to their antigen, these terms include at least a portion of at least one of their CDR domains.

[0052] The term "epitope" is the portion of a molecule that is bound to (e.g., by) an antibody. An epitope can include noncontiguous portions of a molecule (e.g., in a polypeptide, amino acid residues that are not contiguous in the primary sequence of the polypeptide but are sufficiently close to each other in the tertiary and quaternary structure of the polypeptide to be bound by an antibody).

[0053] The "percent identity" of two polynucleotide or two polypeptide sequences is determined using the GAP computer program (part of the GCG Wisconsin Package; version 10.3 (Accelrys, San Diego, Calif.)) with the default parameters to compare sequences.

[0054] The terms "polynucleotide," "oligonucleotide," and "nucleic acid" are used interchangeably throughout and may include DNA molecules (e.g., cDNA or genomic DNA), RNA molecules (e.g., mRNA), DNA or RNA analogs generated using nucleotide analogs (e.g., peptide nucleic acids and non-natural nucleotide analogs), and hybrids thereof. Nucleic acid molecules may be single-stranded or double-stranded. In one embodiment, the nucleic acid molecules encompassed by the present invention comprise a contiguous open reading frame encoding an antibody or a fragment, derivative, mutein, or variant thereof.

[0055] Two single-stranded nucleotides are "complementary" to each other if their sequences can be antiparallel, with each nucleotide in one polynucleotide being opposite to the complementary nucleotide in the other polynucleotide, with no gaps introduced and no unpaired nucleotides found at the 5' or 3' ends of each sequence. A polynucleotide is "complementary" to another polynucleotide if the two polynucleotides can hybridize to each other under moderately stringent conditions. Thus, a polynucleotide can be complementary to another polynucleotide, but not its complementary sequence.

[0056] The term "carrier" refers to a nucleic acid that can be used to introduce another nucleic acid linked thereto into a cell. One type of carrier is a "plasmid", which refers to a linear or circular double-stranded DNA molecule that can be joined to additional nucleic acid segments. Another type of carrier is a viral vector (e.g., replication-defective retroviruses, adenoviruses and adeno-associated viruses), in which additional DNA segments can be introduced into the viral genome. Some carriers are capable of autonomous replication in the host cell into which they are introduced (e.g., bacterial carriers and free mammalian carriers that contain a bacterial origin of replication). Other carriers (e.g., non-free mammalian carriers) are integrated into the host cell genome when introduced into a host cell, and are thereby replicated together with the host genome. An "expression carrier" is a type of carrier that can direct the expression of a selected polynucleotide.

[0057] A nucleotide sequence is "operably linked" to a regulatory sequence if the regulatory sequence affects the expression (e.g., level, time or site of expression) of the nucleotide sequence. A "regulatory sequence" is a nucleic acid that affects the expression (e.g., level, time or site of expression) of a nucleic acid to which it is operably linked. A regulatory sequence may, for example, act directly on the nucleic acid being regulated or through one or more other molecules (e.g., a polynucleotide that binds to the regulatory sequence and / or nucleic acid). Examples of regulatory sequences include promoters, enhancers and other expression control elements (e.g., polyadenylation signals). Further examples of regulatory sequences may be described, for example, in (Non-Patent Document 19); and (Non-Patent Document 20).

[0058] The term "host cell" refers to a cell used to express a nucleic acid, such as those provided herein. A host cell can be a prokaryote, such as E. coli, or it can be a eukaryote, such as a unicellular eukaryote (e.g., yeast or other fungi), a plant cell (e.g., tobacco or tomato plant cell), an animal cell (e.g., human, monkey, hamster, rat, mouse or insect cell), or a hybridoma. Typically, a host cell is a cultured cell that can be transformed or transfected with a peptide-encoding nucleic acid that can then be expressed in the host cell. The phrase "recombinant host cell" can be used to indicate a host cell that has been transformed or transfected with a nucleic acid of predicted expression. A host cell can also be a cell that contains a nucleic acid but does not express the nucleic acid at a desired level unless a control sequence is introduced into the host cell such that it is operably linked to the nucleic acid. It should be understood that the term "host cell" refers not only to the particular subject cell, but also to the progeny or potential progeny of that cell. Due to certain modifications that occur in subsequent generations, such as mutations or environmental influences, such progeny may actually differ from the parent cell, but still be included within the scope of the term as used herein.

[0059] APJ receptor APJ is a G protein-coupled receptor with seven transmembrane units consisting of 377 amino acids (Non-Patent Document 21). To date, studies have shown that APJ is widely distributed in the human central nervous system and various peripheral tissues such as lungs, heart, and chest (Non-Patent Document 1; Non-Patent Document 2), especially in cardiovascular endothelial cells and cardiac tissues (Non-Patent Document 3). APJ is mainly involved in the regulation of the cardiovascular system, and has been reported to have important significance in the regulation of insulin and the regulatory mechanisms of diabetes and obesity-related diseases (Non-Patent Document 22; Non-Patent Document 23). As used herein, "human APJ" and "hAPJ" both refer to human-derived APJ and can be used interchangeably. As used herein, "mouse APJ" and "mAPJ" both refer to mouse-derived APJ and can also be used interchangeably.

[0060] In one embodiment, the antibody provided herein is an antibody that specifically binds to human APJ. In one embodiment, the fusion protein provided herein is an Elabela fusion protein that specifically binds to APJ on the cell membrane, where the fusion protein can activate Elabela / APJ signaling in these cells. In a further embodiment, the fusion protein provided herein is an Elabela fusion protein that binds to human APJ, where the fusion protein can bind to APJ in other species (such as monkey and mouse) and activate Elabela / APJ signaling in these species.

[0061] In one embodiment, the amino acid and polynucleotide sequences of APJ are listed below, with sequence data obtained from the National Center for Biotechnology Information's Gene-Bank database and the European Bioinformatics Institute's Uniprot database. Human (Homo sapiens) polynucleotide (SEQ ID NO:55); Accession number: X89271. Human (Homo sapiens) amino acid (SEQ ID NO:23); Accession number: CAA61546. Monkey (Rhesus macaque) polynucleotide (SEQ ID NO:56); Accession number: AF100206. Monkey (Rhesus macaque) amino acid (SEQ ID NO: 24); Accession number: AAC72404. Rat (Rattus norvegicus) polynucleotide (SEQ ID NO:57); Accession number: AB033170. Rat (Rattus norvegicus) amino acid (SEQ ID NO:25); Accession number: BAA95002. Mouse (Mus musculus) polynucleotide (SEQ ID NO:58); Accession Number: AJ007612; and Mouse (Mus musculus) amino acid (SEQ ID NO:26); Accession Number: CAB50696.

[0062] Vasoactive peptide receptor antibody (APJ antibody) In one embodiment, an APJ antibody is provided herein. In another embodiment, the APJ antibody provided herein is a complete APJ antibody. In another embodiment, the APJ antibody provided herein is an APJ antibody fragment. In another embodiment, the APJ antibody provided herein is a derivative of an APJ antibody. In another embodiment, the APJ antibody provided herein is an APJ antibody mutein. In another embodiment, the APJ antibody provided herein is a variant of an APJ antibody.

[0063] In one embodiment, the APJ antibodies provided herein comprise one, two, three, four, five, or six amino acid sequences, each of which independently corresponds to the amino acid sequence listed below: a. Light chain CDR1 amino acid sequences: SEQ ID NO:1, SEQ ID NO:4, SEQ ID NO:7, and SEQ ID NO:10; b. Light chain CDR2 amino acid sequences: SEQ ID NO:2, SEQ ID NO:5, and SEQ ID NO:8; c. Light chain CDR3 amino acid sequences: SEQ ID NO:3, SEQ ID NO:6, SEQ ID NO:9, and SEQ ID NO:11; d. Heavy chain CDR1 amino acid sequences: SEQ ID NO:12, SEQ ID NO:15, and SEQ ID NO:18; e. Heavy chain CDR2 amino acid sequences: SEQ ID NO:13, SEQ ID NO:16, SEQ ID NO:19, and SEQ ID NO:21; and f. Heavy chain CDR3 amino acid sequences: SEQ ID NO:14, SEQ ID NO:17, SEQ ID NO:20, and SEQ ID NO:22 is selected from.

[0064] Table 1 lists the amino acid sequences of the light chain CDRs of the APJ antibodies provided herein as well as the corresponding polynucleotide coding sequences. Table 2 lists the amino acid sequences of the heavy chain CDRs of the APJ antibodies provided herein as well as the corresponding polynucleotide coding sequences.

[0065] [Table 1]

[0066] [Table 2]

[0067] In one embodiment, an antibody provided herein comprises a sequence that differs by 5, 4, 3, 2 or 1 amino acid addition, substitution and / or deletion from one of the CDR amino acid sequences listed in Tables 1 and 2. In another embodiment, an antibody provided herein comprises a sequence that differs by 4, 3, 2 or 1 amino acid addition, substitution and / or deletion from one of the CDR amino acid sequences listed in Tables 1 and 2.

[0068] In another embodiment, an antibody provided herein comprises a sequence that differs from one of the CDR amino acid sequences listed in Tables 1 and 2 by three, two or one amino acid additions, substitutions and / or deletions.

[0069] In another embodiment, an antibody provided herein comprises a sequence that differs from one of the CDR amino acid sequences listed in Tables 1 and 2 by two or one amino acid addition, substitution and / or deletion.

[0070] In further embodiments, the antibodies provided herein comprise a sequence that differs from one of the CDR amino acid sequences listed in Tables 1 and 2 by one amino acid addition, substitution and / or deletion.

[0071] In one embodiment, the APJ antibodies provided herein comprise one or two amino acid sequences, each independently selected from the amino acid sequences listed below: a. Light chain CDR1 amino acid sequences: SEQ ID NO:1, SEQ ID NO:4, SEQ ID NO:7, and SEQ ID NO:10; b. Heavy chain CDR1 amino acid sequences: SEQ ID NO:12, SEQ ID NO:15, and SEQ ID NO:18 is selected from.

[0072] In another embodiment, the APJ antibody provided herein comprises one or two amino acid sequences, each independently selected from the amino acid sequences listed below: a. Light chain CDR2 amino acid sequences: SEQ ID NO:2, SEQ ID NO:5, and SEQ ID NO:8; b. Heavy chain CDR2 amino acid sequences: SEQ ID NO:13, SEQ ID NO:16, SEQ ID NO:19 and SEQ ID NO:21 is selected from.

[0073] In another embodiment, the APJ antibody provided herein comprises one or two amino acid sequences, each independently selected from the amino acid sequences listed below: a. Light chain CDR3 amino acid sequences: SEQ ID NO:3, SEQ ID NO:6, SEQ ID NO:9, and SEQ ID NO:11; b. Heavy chain CDR3 amino acid sequences: SEQ ID NO:14, SEQ ID NO:17, SEQ ID NO:20 and SEQ ID NO:22 is selected from.

[0074] In another embodiment, the APJ antibody provided herein comprises one, two, three or four amino acid sequences, each independently selected from the amino acid sequences listed below: a. Light chain CDR1 amino acid sequences: SEQ ID NO:1, SEQ ID NO:4, SEQ ID NO:7, and SEQ ID NO:10; b. Heavy chain CDR1 amino acid sequences: SEQ ID NO:12, SEQ ID NO:15, and SEQ ID NO:18; c. Light chain CDR2 amino acid sequences: SEQ ID NO:2, SEQ ID NO:5, and SEQ ID NO:8; d. Heavy chain CDR2 amino acid sequences: SEQ ID NO:13, SEQ ID NO:16, SEQ ID NO:19 and SEQ ID NO:21 is selected from.

[0075] In another embodiment, the APJ antibody provided herein comprises one, two, three or four amino acid sequences, each independently selected from the amino acid sequences listed below: a. Light chain CDR1 amino acid sequences: SEQ ID NO:1, SEQ ID NO:4, SEQ ID NO:7, and SEQ ID NO:10; b. Heavy chain CDR1 amino acid sequences: SEQ ID NO:12, SEQ ID NO:15, and SEQ ID NO:18; c. Light chain CDR3 amino acid sequences: SEQ ID NO:3, SEQ ID NO:6, SEQ ID NO:9, and SEQ ID NO:11; d. Heavy chain CDR3 amino acid sequences: SEQ ID NO:14, SEQ ID NO:17, SEQ ID NO:20 and SEQ ID NO:22 is selected from.

[0076] In further embodiments, the APJ antibodies provided herein comprise one, two, three, or four amino acid sequences, each independently selected from the amino acid sequences listed below: a. Light chain CDR2 amino acid sequences: SEQ ID NO:2, SEQ ID NO:5, and SEQ ID NO:8; b. Heavy chain CDR2 amino acid sequences: SEQ ID NO:13, SEQ ID NO:16, SEQ ID NO:19, and SEQ ID NO:21; c. Light chain CDR3 amino acid sequences: SEQ ID NO:3, SEQ ID NO:6, SEQ ID NO:9, and SEQ ID NO:11; d. Heavy chain CDR3 amino acid sequences: SEQ ID NO:14, SEQ ID NO:17, SEQ ID NO:20 and SEQ ID NO:22 is selected from.

[0077] In one embodiment, the APJ antibody provided herein comprises one, two or three amino acid sequences, each independently selected from the amino acid sequences listed below: SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10 and SEQ ID NO:11.

[0078] In another embodiment, the APJ antibody provided herein comprises one, two or three amino acid sequences, each independently selected from the amino acid sequences listed below: SEQ ID NO:12, SEQ ID NO:13, SEQ ID NO:14, SEQ ID NO:15, SEQ ID NO:16, SEQ ID NO:17, SEQ ID NO:18, SEQ ID NO:19, SEQ ID NO:20, SEQ ID NO:21 and SEQ ID NO:22.

[0079] In one embodiment, the APJ antibody provided herein comprises a combination of light and heavy chain CDR1 amino acid sequences independently selected from the following list: SEQ ID NO:1 and SEQ ID NO:12, SEQ ID NO:4 and SEQ ID NO:15, SEQ ID NO:7 and SEQ ID NO:18, and SEQ ID NO:10 and SEQ ID NO:18.

[0080] In another embodiment, the APJ antibody provided herein comprises a combination of light and heavy chain CDR2 amino acid sequences independently selected from the following list: SEQ ID NO:2 and SEQ ID NO:13, SEQ ID NO:5 and SEQ ID NO:16, SEQ ID NO:8 and SEQ ID NO:19, and SEQ ID NO:5 and SEQ ID NO:21.

[0081] In further embodiments, the APJ antibody provided herein comprises a combination of light and heavy chain CDR3 amino acid sequences independently selected from the following list: SEQ ID NO:3 and SEQ ID NO:14, SEQ ID NO:6 and SEQ ID NO:17, SEQ ID NO:9 and SEQ ID NO:20, and SEQ ID NO:11 and SEQ ID NO:22.

[0082] In one embodiment, the APJ antibody provided herein is a. a combination of light and heavy chain CDR1 amino acid sequences independently selected from the following list: SEQ ID NO:1 and SEQ ID NO:12, SEQ ID NO:4 and SEQ ID NO:15, SEQ ID NO:7 and SEQ ID NO:18, and SEQ ID NO:10 and SEQ ID NO:18; and b. A combination of light and heavy chain CDR2 amino acid sequences independently selected from the following list: SEQ ID NO:2 and SEQ ID NO:13, SEQ ID NO:5 and SEQ ID NO:16, SEQ ID NO:8 and SEQ ID NO:19, and SEQ ID NO:5 and SEQ ID NO:21. Includes.

[0083] In one embodiment, the APJ antibody provided herein is a. a combination of light and heavy chain CDR1 amino acid sequences independently selected from the following list: SEQ ID NO:1 and SEQ ID NO:12, SEQ ID NO:4 and SEQ ID NO:15, SEQ ID NO:7 and SEQ ID NO:18, and SEQ ID NO:10 and SEQ ID NO:18; and b. A combination of light and heavy chain CDR3 amino acid sequences independently selected from the following list: SEQ ID NO:3 and SEQ ID NO:14, SEQ ID NO:6 and SEQ ID NO:17, SEQ ID NO:9 and SEQ ID NO:20, and SEQ ID NO:11 and SEQ ID NO:22. Includes.

[0084] In one embodiment, the APJ antibody provided herein is a. a combination of light and heavy chain CDR2 amino acid sequences independently selected from the following list: SEQ ID NO:2 and SEQ ID NO:13, SEQ ID NO:5 and SEQ ID NO:16, SEQ ID NO:8 and SEQ ID NO:19, and SEQ ID NO:5 and SEQ ID NO:21; and b. A combination of light and heavy chain CDR3 amino acid sequences independently selected from the following list: SEQ ID NO:3 and SEQ ID NO:14, SEQ ID NO:6 and SEQ ID NO:17, SEQ ID NO:9 and SEQ ID NO:20, and SEQ ID NO:11 and SEQ ID NO:22. Includes.

[0085] In a further embodiment, the APJ antibody provided herein is a. a combination of light and heavy chain CDR1 amino acid sequences independently selected from the following list: SEQ ID NO:1 and SEQ ID NO:12, SEQ ID NO:4 and SEQ ID NO:15, SEQ ID NO:7 and SEQ ID NO:18, and SEQ ID NO:10 and SEQ ID NO:18; b. A combination of light and heavy chain CDR2 amino acid sequences independently selected from the following list: SEQ ID NO:2 and SEQ ID NO:13, SEQ ID NO:5 and SEQ ID NO:16, SEQ ID NO:8 and SEQ ID NO:19, and SEQ ID NO:5 and SEQ ID NO:21; and c. A combination of light and heavy chain CDR3 amino acid sequences independently selected from the following list: SEQ ID NO:3 and SEQ ID NO:14, SEQ ID NO:6 and SEQ ID NO:17, SEQ ID NO:9 and SEQ ID NO:20, and SEQ ID NO:11 and SEQ ID NO:22. Includes.

[0086] In one embodiment, the antibody provided herein comprises: (a) light chain CDR1 amino acid sequence: SEQ ID NO:1; Light chain CDR2 amino acid sequence: SEQ ID NO:2; Light chain CDR3 amino acid sequence: SEQ ID NO:3; Heavy chain CDR1 amino acid sequence: SEQ ID NO:12; Heavy chain CDR2 amino acid sequence: SEQ ID NO:13; and Heavy chain CDR3 amino acid sequence: SEQ ID NO:14; (b) light chain CDR1 amino acid sequence: SEQ ID NO:4; Light chain CDR2 amino acid sequence: SEQ ID NO:5; Light chain CDR3 amino acid sequence: SEQ ID NO:6; Heavy chain CDR1 amino acid sequence: SEQ ID NO:15; Heavy chain CDR2 amino acid sequence: SEQ ID NO:16; and Heavy chain CDR3 amino acid sequence: SEQ ID NO:17; (c) light chain CDR1 amino acid sequence: SEQ ID NO:7; Light chain CDR2 amino acid sequence: SEQ ID NO:8; Light chain CDR3 amino acid sequence: SEQ ID NO:9; Heavy chain CDR1 amino acid sequence: SEQ ID NO:18; Heavy chain CDR2 amino acid sequence: SEQ ID NO:19; and Heavy chain CDR3 amino acid sequence: SEQ ID NO:20; (d) light chain CDR1 amino acid sequence: SEQ ID NO: 10; Light chain CDR2 amino acid sequence: SEQ ID NO:5; Light chain CDR3 amino acid sequence: SEQ ID NO:11; Heavy chain CDR1 amino acid sequence: SEQ ID NO:18; Heavy chain CDR2 amino acid sequence: SEQ ID NO:21; and Heavy chain CDR3 amino acid sequence: SEQ ID NO:22 Includes.

[0087] In another embodiment, the antibody provided herein comprises: Light chain CDR1 amino acid sequence: SEQ ID NO:10; Light chain CDR2 amino acid sequence: SEQ ID NO:5; Light chain CDR3 amino acid sequence: SEQ ID NO:11; Heavy chain CDR1 amino acid sequence: SEQ ID NO:18; Heavy chain CDR2 amino acid sequence: SEQ ID NO:21; and Heavy chain CDR3 amino acid sequence: SEQ ID NO:22 Includes.

[0088] In one embodiment, the APJ antibody provided herein comprises one or two amino acid sequences, each amino acid sequence independently selected from the following list: a. the amino acid sequences of the light chain variable domain: SEQ ID NO:59 (L1), SEQ ID NO:60 (L2), SEQ ID NO:61 (L3), SEQ ID NO:62 (L4), and SEQ ID NO:63 (L5); and amino acid sequences which are at least 80%, at least 85%, at least 90%, or at least 95% identical to any of the above sequences; and b. The amino acid sequences of the heavy chain variable domain: SEQ ID NO:64 (H1), SEQ ID NO:65 (H2), SEQ ID NO:66 (H3), SEQ ID NO:67 (H4) and SEQ ID NO:68 (H5); and amino acid sequences that are at least 80%, at least 85%, at least 90% or at least 95% identical to any of the above sequences. is selected from.

[0089] In another embodiment, the polynucleotide coding sequence of the APJ antibody provided herein comprises one or two polynucleotide coding sequences, each polynucleotide coding sequence independently comprising a polynucleotide sequence listed below: a. light chain variable domain polynucleotide coding sequences: SEQ ID NO:69, SEQ ID NO:70, SEQ ID NO:71, SEQ ID NO:72, and SEQ ID NO:73; and polynucleotide sequences which are at least 80%, at least 85%, at least 90%, or at least 95% identical to any of the above sequences; and b. Heavy chain variable domain polynucleotide coding sequences: SEQ ID NO:74, SEQ ID NO:75, SEQ ID NO:76, SEQ ID NO:77, and SEQ ID NO:78; and polynucleotide sequences that are at least 80%, at least 85%, at least 90%, or at least 95% identical to any of the above sequences. is selected from.

[0090] In one embodiment, the APJ antibody provided herein comprises an amino acid sequence independently selected from the following list: SEQ ID NO:59, SEQ ID NO:60, SEQ ID NO:61, SEQ ID NO:62, and SEQ ID NO:63.

[0091] In another embodiment, the APJ antibody provided herein comprises an amino acid sequence independently selected from the following list: SEQ ID NO:64, SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, and SEQ ID NO:68.

[0092] In one embodiment, the APJ antibody provided herein comprises a combination of amino acid sequences independently selected from the light and heavy chain variable domain amino acid sequences listed below: SEQ ID NO:59 and SEQ ID NO:64 (L1H1), SEQ ID NO:60 and SEQ ID NO:65 (L2H2), SEQ ID NO:61 and SEQ ID NO:66 (L3H3), SEQ ID NO:62 and SEQ ID NO:67 (L4H4), and SEQ ID NO:63 and SEQ ID NO:68 (L5H5).

[0093] The designation "LxHy" may also be used to refer to the APJ antibodies provided herein, where "x" corresponds to the light chain variable region sequence code and "y" corresponds to the heavy chain variable region sequence code. For example, L2H2 is a complete antibody having a light chain variable region comprising the amino acid sequence of SEQ ID NO:60 (L2) and a heavy chain variable region comprising the amino acid sequence of SEQ ID NO:65 (H2).

[0094] In one embodiment, the APJ antibodies provided herein comprise one or two amino acid sequences, each independently selected from the amino acid sequences listed below: a. the amino acid sequences of the light chain constant domain: SEQ ID NO:79, SEQ ID NO:80, and SEQ ID NO:81; and b. Heavy chain constant domain amino acid sequences: SEQ ID NO:82, SEQ ID NO:83 and SEQ ID NO:84 is selected from.

[0095] In another embodiment, the APJ antibody provided herein comprises a combination of amino acid sequences independently selected from the amino acid sequences of the light and heavy chain constant domains listed below: SEQ ID NO:79 and SEQ ID NO:82, SEQ ID NO:80 and SEQ ID NO:83, SEQ ID NO:80 and SEQ ID NO:84, SEQ ID NO:81 and SEQ ID NO:83, and SEQ ID NO:81 and SEQ ID NO:84.

[0096] In one embodiment, the APJ antibody provided herein comprises the amino acid sequences of the light and heavy chain CDRs and FRs (framework) as enumerated herein. The amino acid sequences of the FRs are included in the light or heavy chain variable domains and are not separately set forth. In one embodiment, the antibody comprises the light chain CDR1 sequence as enumerated herein. In another embodiment, the antibody comprises the light chain CDR2 sequence as enumerated herein. In another embodiment, the antibody comprises the light chain CDR3 sequence as enumerated herein. In another embodiment, the antibody comprises the heavy chain CDR1 sequence as enumerated herein. In another embodiment, the antibody comprises the heavy chain CDR2 sequence as enumerated herein. In another embodiment, the antibody comprises the heavy chain CDR3 sequence as enumerated herein. In another embodiment, the antibody comprises the light chain FR1 sequence as enumerated herein. In another embodiment, the antibody comprises the light chain FR2 sequence as enumerated herein. In another embodiment, the antibody comprises the light chain FR3 sequence as enumerated herein. In another embodiment, the antibody comprises the light chain FR4 sequence as enumerated herein. In another embodiment, the antibody comprises the heavy chain FR1 sequence as enumerated herein. In another embodiment, the antibody comprises a heavy chain FR2 sequence as herein described. In another embodiment, the antibody comprises a heavy chain FR3 sequence as herein described. In a further embodiment, the antibody comprises a heavy chain FR4 sequence as herein described.

[0097] In one embodiment, the light chain CDR3 sequence of the antibody differs from the light chain CDR3 amino acid sequence SEQ ID NO: 11 shown above by not more than 6, 5, 4, 3, 2 or 1 amino acid addition, substitution and / or deletion. In another embodiment, the heavy chain CDR sequence of the antibody differs from the heavy chain CDR3 amino acid sequence SEQ ID NO: 22 shown above by not more than 6, 5, 4, 3, 2 or 1 amino acid addition, substitution and / or deletion. In a further embodiment, the light chain CDR3 sequence of the antibody differs from the light chain CDR3 amino acid sequence SEQ ID NO: 11 shown above by not more than 6, 5, 4, 3, 2 or 1 amino acid addition, substitution and / or deletion and the heavy chain CDR3 sequence of the antibody differs from the heavy chain CDR3 amino acid sequence SEQ ID NO: 22 shown above by not more than 6, 5, 4, 3, 2 or 1 amino acid addition, substitution and / or deletion.

[0098] In one embodiment, the APJ antibody provided herein comprises an amino acid sequence of a light chain variable domain selected from the L4 (SEQ ID NO: 62) or L5 (SEQ ID NO: 63) light chain variable domain sequences listed herein. In one embodiment, the amino acid sequence of the light chain variable domain of the APJ antibody differs from the amino acid sequence of one of the light chain variable domains of L4 (SEQ ID NO: 62) or L5 (SEQ ID NO: 63) by 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 amino acid difference, each sequence difference being, independently, a deletion, insertion, or substitution of an amino acid residue. In another embodiment, the amino acid sequence of the light chain variable domain of the APJ antibody comprises an amino acid sequence that is at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97%, or at least 99% identical to the amino acid sequence of one of the light chain variable domains of L4 (SEQ ID NO: 62) or L5 (SEQ ID NO: 63). In another embodiment, the polynucleotide coding sequence of the light chain variable domain of the APJ antibody comprises a nucleotide coding sequence that is at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97% or at least 99% identical to the polynucleotide coding sequence of one of L4 (SEQ ID NO: 72) or L5 (SEQ ID NO: 73). In another embodiment, the polynucleotide coding sequence of the light chain variable domain of the APJ antibody comprises a polynucleotide sequence that hybridizes under moderate conditions to a complementary polynucleotide coding sequence of one of the light chain variable domains of L4 (SEQ ID NO: 72) or L5 (SEQ ID NO: 73). In a further embodiment, the polynucleotide coding sequence of the light chain variable domain of the APJ antibody comprises a polynucleotide sequence that hybridizes under stringent conditions to a complementary polynucleotide coding sequence of one of the light chain variable domains of L4 (SEQ ID NO: 72) or L5 (SEQ ID NO: 73).

[0099] In one embodiment, the APJ antibody provided herein comprises an amino acid sequence of a heavy chain variable domain selected from the H4 (SEQ ID NO:67) or H5 (SEQ ID NO:68) heavy chain variable domain sequences listed herein. In another embodiment, the amino acid sequence of the heavy chain variable domain of the APJ antibody differs from the amino acid sequence of one of the heavy chain variable domains of H4 (SEQ ID NO:67) or H5 (SEQ ID NO:68) by 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 amino acid, and each sequence difference is independently a deletion, insertion, or substitution of one amino acid residue. In another embodiment, the amino acid sequence of the heavy chain variable domain of the APJ antibody comprises an amino acid sequence that is at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97%, or at least 99% identical to the amino acid sequence of one of the heavy chain variable domains of H4 (SEQ ID NO:67) or H5 (SEQ ID NO:68). In another embodiment, the heavy chain variable domain of the APJ antibody comprises a polynucleotide coding sequence that is at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97% or at least 99% identical to the heavy chain variable domain polynucleotide coding sequence of one of H4 (SEQ ID NO: 77) or H5 (SEQ ID NO: 78). In another embodiment, the polynucleotide coding sequence of the APJ antibody heavy chain variable domain comprises a polynucleotide sequence that hybridizes under moderately stringent conditions to the complementary polynucleotide coding sequence of the heavy chain variable domain of one of H4 (SEQ ID NO: 77) or H5 (SEQ ID NO: 78). In one embodiment, the polynucleotide coding sequence of the APJ antibody heavy chain variable domain comprises a polynucleotide sequence that hybridizes under stringent conditions to the complementary polynucleotide coding sequence of the heavy chain variable domain of one of H4 (SEQ ID NO: 77) or H5 (SEQ ID NO: 78).

[0100] In one embodiment, the antibody provided herein is an antibody that comprises L1H1 (SEQ ID NO:59 and SEQ ID NO:64), L2H2 (SEQ ID NO:60 and SEQ ID NO:65), L3H3 (SEQ ID NO:61 and SEQ ID NO:66), L4H4 (SEQ ID NO:62 and SEQ ID NO:67) or L5H5 (SEQ ID NO:63 and SEQ ID NO:68) or a combination of a desired phenotype thereof (e.g., IgA, IgG1, IgG2a, IgG2b, IgG3, IgM, IgE or IgD) or a Fab or F(ab')2 fragment thereof.

[0101] In one embodiment, the antibody provided herein is an antibody that comprises a combination of L4H4 (SEQ ID NO: 62 and SEQ ID NO: 67) or L5H5 (SEQ ID NO: 63 and SEQ ID NO: 68), or an exchange isotype thereof (e.g., IgA, IgG1, IgG2a, IgG2b, IgG3, IgM, IgE or IgD), or a combination of Fab or F(ab')2 fragments thereof.

[0102] The antibodies provided herein may comprise any of the constant regions known in the art. The light chain constant region may be, for example, a kappa or lambda light chain constant region, such as a mouse kappa or lambda light chain constant region. The heavy chain constant region may be, for example, an alpha, delta, epsilon, gamma, or mu heavy chain constant region, such as a mouse alpha, delta, epsilon, gamma, or mu heavy chain constant region. In one embodiment, the light or heavy chain constant region is a fragment, derivative, variant, or mutant of a native constant region.

[0103] In one embodiment, the antibody provided herein further comprises a human light chain kappa constant domain or a fragment thereof. The amino acid sequence of the light chain constant region is as follows: The amino acid sequence of the human light chain kappa constant domain: (SEQ ID NO: 80); and Amino acid sequence of human light chain lambda constant domain: (SEQ ID NO:81).

[0104] In another embodiment, the antibody provided herein further comprises a human heavy chain or a fragment thereof. The amino acid sequence of the heavy chain constant domain is provided as follows: The amino acid sequence of the human heavy chain constant domain (hIgG2): (SEQ ID NO: 83), and Amino acid sequence of human heavy chain constant domain (hIgG4): (SEQ ID NO:84).

[0105] In one embodiment, the heavy and light chain amino acid sequences of the APJ antibody provided herein are as follows: SEQ ID NO:157 and SEQ ID NO:158.

[0106] In one embodiment, the APJ antibody provided herein is selected from a murine antibody, a humanized antibody, a chimeric antibody, a monoclonal antibody, a polyclonal antibody, a recombinant antibody, an antigen-binding antibody fragment, a single chain antibody, a two chain antibody, a three chain antibody, a four chain antibody, a Fab fragment, a F(ab')x fragment, a structural domain antibody, an IgD antibody, an IgE antibody, an IgM antibody, an IgG1 antibody, an IgG2 antibody, an IgG3 antibody, or an IgG4 antibody.

[0107] In another embodiment, the APJ antibody provided herein is an APJ monoclonal antibody.

[0108] In another embodiment, the APJ antibody provided herein is a monoclonal antibody comprising a combination of amino acid sequences selected from the following list: SEQ ID NO:59 and SEQ ID NO:64, SEQ ID NO:60 and SEQ ID NO:65, SEQ ID NO:61 and SEQ ID NO:66, SEQ ID NO:67 and SEQ ID NO:63, and SEQ ID NO:63 and SEQ ID NO:68.

[0109] In one embodiment, the APJ antibody provided herein is a murine APJ antibody. In another embodiment, the APJ antibody provided herein is a humanized APJ antibody.

[0110] In one embodiment, the Kd value of the APJ antibody provided herein is about 1 nM to 200 nM or about 1 nM to 100 nM.

[0111] Antibodies and antibody fragments In one embodiment, the antibodies provided herein are full-length antibodies (including polyclonal, monoclonal, chimeric, humanized or human antibodies having full-length heavy and / or light chains). In another embodiment, the antibodies provided herein are antibody fragments, such as F(ab')2, Fab, Fab', Fv, Fc or Fd fragments, which may be incorporated into single domain antibodies, single chain antibodies, maxibodies, minibodies, intrabodies, two-chain antibodies, three-chain antibodies, four-chain antibodies, v-NAR or bis-scFv (see, for example, (Non-Patent Document 24)). In another embodiment, the antibodies provided herein also include antibody polypeptides such as those disclosed in (Patent Document 8), including fibronectin polypeptide monospecific antibodies. In another embodiment, the antibodies provided herein also include other antibody polypeptides disclosed in (Patent Document 9), which are single chain polypeptides.

[0112] In one embodiment, the variable regions of the IgG genes expressing the monoclonal antibodies of interest in the hybridomas are amplified using nucleotide primers. These primers can be synthesized by those skilled in the art or can be prepared by, among others, V Ha , V Hb , V Hc , V Hd , C H1 , V L and C L Primers for mouse and human variable regions, including primers for the V region, can be purchased from commercial vendors that synthesize these primers. These primers can be used to amplify the heavy or light chain variable regions, which can then be inserted into vectors such as IMMUNOZAP™ H or IMMUNOZAP™ L (Stratagene), respectively. These vectors can then be introduced into E. coli, yeast, or mammalian-based systems for expression. H and V L Large amounts of single-chain proteins containing fusions of the domains can be produced using these methods (see, for example, Non-Patent Document 15).

[0113] It should be understood by those skilled in the art that certain proteins, such as antibodies, can undergo various post-translational modifications. The type and extent of these modifications often depend on the host cell line and culture conditions used to express the protein. Such modifications can include changes in glycosylation, methionine oxidation, diketopiperidine formation, aspartate isomerization, and asparagine deamidation. Frequent modifications of carboxypeptidases can result in the loss of carboxyl-terminal basic residues, such as lysine or arginine (as described in (Non-Patent Document 25)).

[0114] A common method for the production of mouse monoclonal antibodies is by hybridoma cells. Monoclonal antibodies can be isolated and purified by a variety of established techniques. Such isolation techniques include affinity chromatography using protein-A sepharose, size exclusion chromatography, and ion exchange chromatography (see, for example, (Non-Patent Document 26); (Non-Patent Document 27)). Monoclonal antibodies can be purified by affinity chromatography using a suitable ligand selected based on the specific properties of the antibody (e.g., heavy or light chain isotype, binding specificity, etc.). Examples of suitable ligands immobilized on a solid support include protein A, protein G, anti-constant region (light or heavy chain) antibodies, anti-idiotypic antibodies, and TGF-β binding proteins or fragments or variants thereof.

[0115] As described by (Non-Patent Document 28), molecular evolution of the complementarity determining region (CDR) at the center of the antibody binding site has also been used to isolate antibodies with increased affinity, for example, antibodies with increased affinity for c-erbB-2. Thus, such techniques are useful for preparing antibodies against human APJ.

[0116] Antibodies against human APJ can be used, for example, in assays to detect the presence of APJ, either in vitro or in vivo.

[0117] Antibodies can be prepared by any of the conventional techniques. For example, antibodies can be purified from cells that naturally express them (e.g., antibodies can be purified from the hybridoma that produces them) or can be produced in recombinant expression systems using any technique known in the art. See, for example, (Non-Patent Document 29); and (Non-Patent Document 30). This is explained in the section on nucleic acids below.

[0118] Antibodies can be prepared by any known technique and screened for desired properties. Some techniques involve the isolation and manipulation of nucleic acids encoding the polypeptide chain (or portions thereof) of the relevant antibody (e.g., an anti-APJ antibody). The nucleic acid can be fused to another relevant nucleic acid or modified by recombinant DNA techniques (e.g., induced mutagenesis or other conventional techniques) to add, delete, or substitute one or more amino acid residues.

[0119] If it is necessary to improve the affinity of an antibody according to the invention containing one or more of the above-mentioned CDRs, such an antibody can be obtained by several affinity maturation protocols, including maintenance of the CDRs (Non-Patent Document 31), chain shuffling (Non-Patent Document 32), the use of mutant strains of Escherichia coli (E. coli) (Non-Patent Document 33), DNA shuffling (Non-Patent Document 34), phage display (Non-Patent Document 35) and further PCR techniques (Non-Patent Document 36). All these methods of affinity maturation are described in (Non-Patent Document 37).

[0120] In one embodiment, fragments of APJ antibodies are provided herein. Such fragments may contain sequences entirely derived from the antibody or additional sequences. Examples of antigen-binding fragments include Fab, F(ab')2, single-chain antibodies, diabodies, triabodies, tetrabodies, and domain antibodies. Other examples are provided in (Non-Patent Document 38).

[0121] Single chain antibodies can be formed by linking heavy and light chain variable domain (Fv region) fragments by an amino acid bridge (short peptide linker) to generate a single polypeptide chain. Such a single chain Fv (scFv) comprises two variable domain polypeptides (V L and V H ) have been prepared by fusion DNA encoding a peptide linker between DNAs encoding the variable domains L1H1 and L2H1. The resulting polypeptides can fold back on themselves to form antigen-binding monomers, or they can form multimers (e.g., dimers, trimers, or tetramers) depending on the length of the flexible linker between the two variable domains (Non-Patent Document 39; Non-Patent Document 40). By combining various VL- and VH-containing polypeptides, multimeric scFvs that bind to various epitopes can be formed (Non-Patent Document 41). Techniques developed for the production of single-chain antibodies include those described in (Patent Document 10); (Non-Patent Document 42); (Non-Patent Document 43); (Non-Patent Document 44); (Non-Patent Document 45). Single-chain antibodies derived from the antibodies provided herein, including but not limited to scFvs comprising the variable domain combination L1H1, are encompassed by the present invention.

[0122] Antigen-binding fragments derived from an antibody can also be obtained according to conventional methods, for example by proteolytic hydrolysis of the antibody, for example by pepsin or papain digestion of the whole antibody. As an example, antibody fragments can be generated by enzymatic cleavage of the antibody with pepsin, which produces an SS fragment called F(ab')2. This fragment can be further cleaved with a thiol reducing agent to produce a 3.5S Fab' monovalent fragment. Optionally, the cleavage reaction can be performed with a blocking group for sulfhydryl groups, which results in cleavage of disulfide bonds. As an alternative, enzymatic cleavage with papain produces two monovalent Fab fragments and an Fc fragment directly. These methods are described, for example, by Goldenberg et al. (Patent Document 11), (Non-Patent Document 46); (Non-Patent Document 47); (Non-Patent Document 48); and (Non-Patent Document 49). Other methods for cleaving antibodies, such as separating heavy chains to form monovalent light-heavy chain fragments (Fd), other cleavage of fragments, or other enzymatic, chemical, or genetic techniques may also be used so long as the fragment binds to the antigen recognized by the intact antibody.

[0123] Another form of antibody fragment is a peptide comprising one or more complementarity determining regions (CDRs) of an antibody. The CDRs are obtained by constructing a polynucleotide encoding the CDRs. Such polynucleotides are prepared, for example, by using the polymerase chain reaction to synthesize the variable region using mRNA of an antibody-producing cell as a template (see, for example, (50); (51); and (52)). The antibody fragment may further comprise at least one variable region domain of an antibody described herein. Thus, for example, a V region domain may be a monomer and a V region domain. H Or V L domain, which can be 1×10 -7 It can bind to APJ with an affinity of M or greater.

[0124] The variable region domain may be any naturally occurring variable domain or an engineered form thereof. By engineered form is meant a variable region domain that has been generated using recombinant DNA engineering techniques. Such engineered forms include those that have been generated from a particular antibody variable region, for example, by insertions, deletions or changes in or to the amino acid sequence of the particular antibody. A specific example includes an engineered variable region domain that contains at least one CDR and optionally one or more framework amino acids from a first antibody and the remaining part of the variable region domain from a second antibody.

[0125] The variable region domain may be covalently linked at the C-terminal amino acid to at least one other antibody domain or fragment thereof. Thus, for example, a V H Domain: Immunoglobulin C H1 domain or a fragment thereof. L The domain is C K Thus, for example, an antibody can be a Fab fragment, in which the antigen-binding domains are linked to a C-terminus, respectively a C H1 and the related V covalently linked to the Cκ domain. H and V L Contains the domain C H1 The domain may be extended with additional amino acids to produce a hinge region or part of a hinge region domain, for example as found in a Fab' fragment, or may be extended with additional amino acids to produce a hinge region or part of a hinge region domain, such as found in an antibody C fragment. H2 and C H3 Further domains such as the domain may result.

[0126] Antibody Derivatives and Variants The nucleotide sequences of L1 and H1 can be modified, for example, by random mutagenesis or by site-specific mutagenesis (e.g., oligonucleotide-directed site-specific mutagenesis) to generate modified polynucleotides containing one or more specific nucleotide substitutions, deletions, or insertions compared to the non-mutated polynucleotide. Examples of techniques for making such modifications are described in (Non-Patent Document 53); (Non-Patent Document 54); (Non-Patent Document 55); (Non-Patent Document 56); and (Patent Document 12) and (Patent Document 13). These and other methods can be used to generate derivatives of, for example, APJ antibodies that have desired properties, such as improved affinity, avidity, or specificity for APJ, or in vivo or in vitro stability, or reduced in vivo side effects, compared to non-derivatized antibodies.

[0127] Other derivatives of anti-APJ receptor antibodies within the scope of the present invention include covalent or aggregative conjugates of anti-APJ receptor antibodies or fragments thereof with other proteins or polypeptides, such as by expression of recombinant fusion proteins containing heterologous polypeptides fused to the N-terminus or C-terminus of the anti-APJ antibody polypeptide. For example, the conjugated peptide can be a heterologous signal (or leader) polypeptide, such as a peptide such as the yeast α-factor leader or an epitope tag. Antibody containing fusion proteins can include peptides added to facilitate purification or identification of the antigen binding protein (e.g., poly-His). The antibody can also be linked to a FLAG peptide, as described in (57) and (14). The FLAG peptide is highly antigenic and provides an epitope that is reversibly bound by a specific monoclonal antibody (mAb), allowing for rapid assay and easy purification of expressed recombinant proteins. Reagents useful for preparing fusion proteins in which the FLAG peptide is fused to a given polypeptide are commercially available (Sigma, St. Louis, Mo.). In another embodiment, oligomers containing one or more antibodies can be used as APJ receptor antagonists. The oligomers can be in the form of covalently or non-covalently linked dimers, trimers or higher oligomers. The use of oligomers containing two or more antibodies is envisioned, one example being homodimers. Other oligomers include heterodimers, homotrimers, heterotrimers, homotetramers, heterotetramers, etc.

[0128] One embodiment relates to oligomers comprising multiple antibodies linked through covalent or non-covalent interactions between peptide moieties fused to the antibodies. Such peptides can be peptide linkers (spacers) or peptides with properties that promote oligomerization. Leucine zippers and certain polypeptides derived from antibodies are peptides that can promote oligomerization of antibodies linked thereto, as described in more detail below.

[0129] In certain embodiments, the oligomer comprises two to four antibodies. The antibodies of the oligomer can be in any form as described above, such as variants or fragments. Preferably, the oligomer comprises an antibody that has APJ binding activity.

[0130] In one embodiment, oligomers are prepared using polypeptides derived from immunoglobulins. Preparation of fusion proteins containing certain heterologous polypeptides fused to various portions of antibody-derived polypeptides (including Fc domains) has been described, for example, by (Non-Patent Document 58); (Non-Patent Document 59); and (Non-Patent Document 60). One embodiment provided herein relates to a dimer containing two fusion proteins generated by fusing the Elabela fragment of an anti-APJ antibody to the Fc region of an antibody. Dimers can be made, for example, by inserting a gene fusion encoding the fusion protein into an appropriate expression vector, expressing the gene fusion in a host cell transformed with the recombinant expression vector, and allowing the assembly of antibody molecules closely resembling the expressed fusion proteins, whereupon interchain disulfide bonds are formed between the Fc portions to obtain a dimer.

[0131] The term "Fc polypeptide" as used herein includes native and mutein forms of polypeptides derived from the Fc region of an antibody. Also included are truncated forms of such polypeptides containing the hinge region that promotes dimerization. Fusion proteins containing an Fc portion (and oligomers formed therefrom) offer the advantage of easy purification by affinity chromatography on Protein A or Protein G columns.

[0132] One suitable Fc polypeptide described in (Patent Document 15) (hereby incorporated by reference) is a single chain polypeptide extending from the N-terminal hinge region of a human IgG1 antibody to the native C-terminus of the Fc region. Another useful Fc polypeptide is the Fc mutein described in (Patent Document 16) and (Non-Patent Document 61). The amino acid sequence of this mutein is identical to that of the native Fc sequence shown in (Patent Document 15) except that amino acid 19 is changed from Leu to Ala, amino acid 20 is changed from Leu to Glu, and amino acid 22 is changed from Gly to Ala. The mutein exhibits reduced affinity for the Fc receptor. In other embodiments, the variable portion of the heavy and / or light chain of the APJ antibody may be replaced with the variable portion of the antibody heavy and / or light chain.

[0133] Alternatively, the oligomer is a fusion protein comprising multiple antibodies with or without peptide linkers (spacer peptides). Among the suitable peptide linkers are those described in WO 2005 / 023961 and WO 2005 / 023976.

[0134] Another method for preparing oligomeric antibodies involves the use of leucine zippers. Leucine zipper domains are peptides that promote oligomerization of the proteins in which they are found. Leucine zippers were originally identified in several DNA-binding proteins (62) and have since been found in a variety of different proteins. Among the known leucine zippers are natural peptides and their derivatives that dimerize or trimerize. Examples of leucine zipper domains suitable for producing soluble oligomeric proteins are described in (Patent Document 19), and a leucine zipper derived from pulmonary surfactant protein D (SPD) is described in (63) (incorporated herein by reference). The use of modified leucine zippers that allow stable trimerization of heterologous proteins fused thereto is described in (64). In one method, a recombinant fusion protein containing an anti-APJ antibody fragment or derivative fused to a leucine zipper peptide is expressed in a suitable host cell and the formed soluble oligomeric anti-APJ antibody fragment or derivative is recovered from the culture supernatant.

[0135] In another embodiment, the antibody derivative may comprise at least one of the CDRs disclosed herein. For example, one or more CDRs may be incorporated into known antibody framework regions (IgG1, IgG2, etc.) or conjugated to a suitable vehicle to increase its half-life. Suitable vehicles include, but are not limited to, Fc, albumin, transferrin, etc. These and other suitable vehicles are known in the art. Such conjugated CDR peptides may be in monomeric, dimeric, tetrameric, or other forms. In one embodiment, one or more water-soluble polymers are attached at one or more specific positions, for example, at the amino terminus of the binding agent. In one example, the antibody derivative comprises one or more water-soluble polymer linkages, including, but not limited to, polyethylene glycol, polyoxyethylene glycol, or polypropylene glycol. See, for example, U.S. Patent No. 5,233,631; U.S. Patent No. 5,233,631; U.S. Patent No. 5,233,631; U.S. Patent No. 5,233,631; and U.S. Patent No. 5,233,631. In certain embodiments, the derivatives include one or more of monomethoxy-polyethylene glycol, dextran, cellulose or other carbohydrate-based polymers, poly-(N-vinylpyrrolidone)-polyethylene glycol, propylene glycol homopolymer, propylene oxide / ethylene oxide copolymer, polyoxyethylated polyol (e.g., glycerol) and polyvinyl alcohol, and mixtures of such polymers. In certain embodiments, one or more water-soluble polymers are randomly attached to one or more side chains. In certain embodiments, PEG can serve to improve the therapeutic capabilities of binding agents such as antibodies. Some such methods are described, for example, in US Pat. No. 5,399,363, which is incorporated herein by reference for any purpose.

[0136] Antibodies with at least one amino acid substitution are provided herein, so long as the antibody retains binding specificity. Thus, modifications to the antibody structure are encompassed within the scope of the present invention. These may include amino acid substitutions that do not destroy the antibody's ability to bind human APJ, which may be conservative or non-conservative. Conservative amino acid substitutions may include non-natural amino acid residues that are typically incorporated by chemical peptide synthesis rather than synthesis in biological systems. This includes peptidomimetics and other reverse or inverted forms of amino acid moieties. Conservative amino acid substitutions may also include the replacement of natural amino acid residues with standard residues, such that there is little or no effect on the polarity or charge of the amino acid residue at that position. Non-conservative substitutions may include replacing a member of one class of amino acids or amino acid mimetics with a member from another class that has different physical properties (e.g., size, polarity, hydrophobicity, charge).

[0137] Furthermore, one skilled in the art can generate mutants to be tested that contain a single amino acid substitution at each desired amino acid residue. Mutants can then be screened using activity assays known to those skilled in the art. Such mutants can be used to collect information about suitable mutants. For example, if it is found that a change to a particular amino acid residue leads to destroyed, undesirably reduced or inappropriate activity, the mutant with such a change can be avoided. In other words, based on the information collected from such routine experiments, one skilled in the art can easily determine the amino acids for which further substitution should be avoided, alone or in combination with other mutations.

[0138] In certain embodiments, one skilled in the art can determine suitable variants of the polypeptides described herein using well-known techniques. In certain embodiments, one skilled in the art can identify suitable regions of the molecule that can be changed without destroying activity by targeting regions that are not important for activity. In certain embodiments, one can identify residues and portions of the molecule that are conserved among similar polypeptides. In certain embodiments, regions that may be important for biological activity or structure can also be subject to conservative amino acid substitutions without destroying biological activity or adversely affecting the polypeptide structure. Additionally, one skilled in the art can consider structure-function studies that identify residues in similar polypeptides that are important for activity or structure. In light of such comparisons, one can predict the importance of amino acid residues in the protein that correspond to amino acid residues that are important for activity or structure in the similar protein. One skilled in the art can select chemically similar amino acid substitutions in place of such predicted important amino acid residues.

[0139] In certain embodiments, one skilled in the art can also analyze the three-dimensional structure and amino acid sequence relative to the corresponding structure in similar polypeptides. Given such information, one skilled in the art can predict the alignment of amino acid residues of an antibody with respect to its three-dimensional structure. In certain embodiments, one skilled in the art can choose not to make radical changes to amino acid residues predicted to be on the surface of the protein, since such residues may be involved in important interactions with other molecules. Several scientific publications are devoted to the prediction of secondary structure. See (Non-Patent Document 65); (Non-Patent Document 66); (Non-Patent Document 67); (Non-Patent Document 68); (Non-Patent Document 69) and (Non-Patent Document 70). In addition, computer programs are now available that aid in predicting secondary structure. For example, two polypeptides or proteins with more than 30% sequence identity or more than 40% similarity often have similar structural topologies. The recent growth of the protein structural database (PDB) has provided improved predictability of secondary structure, including the potential number of folds within the structure of a polypeptide or protein. See (Non-Patent Document 71). It has been suggested that there are a limited number of folds in a given polypeptide or protein, and that after a critical number of structures have been determined, structure prediction becomes significantly more accurate (72).

[0140] Additional methods for predicting secondary structure include "threading" (Non-Patent Document 73; Non-Patent Document 74), "profile analysis" (Non-Patent Document 75; Non-Patent Document 76; Non-Patent Document 77), and "evolutionary association" (see Non-Patent Document 71 and Non-Patent Document 72). In certain embodiments, the antibody variants include glycosylation variants, in which the number and / or type of glycosylation sites have been altered compared to the amino acid sequence of the parent polypeptide. In certain embodiments, the variants include a greater or lesser number of N-linked glycosylation sites than the native protein. Alternatively, removal of such sequences by substitution removes existing N-linked carbohydrate chains. Rearrangements of N-linked carbohydrate chains are also provided, in which one or more N-linked glycosylation sites (typically those that are naturally occurring) are deleted and one or more new N-linked sites are generated. Additional preferred antibody variants include cysteine ​​variants, in which one or more cysteine ​​residues are deleted or replaced with another amino acid (e.g., serine) compared to the parent amino acid sequence. Cysteine ​​variants can be useful when antibodies must be refolded into a biologically active conformation, for example after isolation of insoluble inclusion bodies. Cysteine ​​variants generally have fewer cysteine ​​residues than the native protein, and typically have an even number to minimize interactions resulting from unpaired cysteines.

[0141] Desired amino acid substitutions (whether conservative or non-conservative) can be determined by one of skill in the art when such substitutions are desired. In certain embodiments, amino acid substitutions can be used to identify important residues of antibodies to human APJ or to increase or decrease the affinity of the antibodies to human APJ described herein.

[0142] According to certain embodiments, preferred amino acid substitutions are those that (1) reduce susceptibility to proteolysis, (2) reduce susceptibility to oxidation, (3) modify binding affinity to form protein complexes, (4) modify binding affinity, and / or (5) confer or modulate other physicochemical or functional properties in such polypeptides. According to certain embodiments, single or multiple amino acid substitutions (in certain embodiments, conservative amino acid substitutions) can be made in the native sequence (in certain embodiments, in portions of the polypeptide outside of the domains that form intermolecular contacts). In certain embodiments, conservative amino acid substitutions typically cannot substantially alter the structural features of the parent sequence (e.g., the substituted amino acid should not disrupt helices present in the parent sequence or other types of secondary structure that characterize the parent sequence). Examples of secondary and tertiary structures of polypeptides that are recognized in the art are described in (Non-Patent Document 78); (Non-Patent Document 79); and (Non-Patent Document 80), each of which is incorporated herein by reference.

[0143] In certain embodiments, the antibodies of the invention may be chemically conjugated to polymers, lipids, or other moieties.

[0144] The antigen binding agent may comprise at least one of the CDRs described herein incorporated into a biocompatible framework structure. In one embodiment, the biocompatible framework structure comprises a polypeptide or a portion thereof sufficient to form a conformationally stable structural support, or framework, or scaffold, capable of presenting one or more sequences of amino acids that bind to an antigen (e.g., CDRs, variable regions, etc.) in a localized surface region. Such structures may be native polypeptides or polypeptide "folds" (structural motifs) or may have one or more modifications, such as additions, deletions, or substitutions of amino acids, compared to native polypeptides or folds. These scaffolds may be derived from any species (or more than one species) of polypeptide, such as humans, other mammals, other vertebrates, invertebrates, plants, bacteria, or viruses.

[0145] Typically, biocompatible framework structures are based on protein scaffolds or skeletons other than immunoglobulin domains, for example those based on fibronectin, ankyrin, lipocalin, neocarzinostatin, cytochrome b, CP1 zinc finger, PST1, coiled coil, LACI-D1, Z domain and tendamistat domains can be used (see, for example, (81)).

[0146] Moreover, those skilled in the art will recognize that suitable binding agents include portions of these antibodies, such as one or more of the heavy chain CDR1, CDR2, CDR3, light chain CDR1, CDR2, and CDR3 specifically disclosed herein. At least one of the heavy chain CDR1, CDR2, CDR3, CDR1, CDR2, and CDR3 regions may have at least one amino acid substitution, so long as the antibody retains the binding specificity of the unsubstituted CDR. The non-CDR portion of the antibody may be a non-protein molecule, where the binding agent cross-blocks the binding of the antibody disclosed herein to human APJ. The non-CDR portion of the antibody may be a non-protein molecule, where the antibody exhibits a binding pattern to human Elabela peptide in a competitive binding assay similar to that exhibited by antibody L4H4. The non-CDR portion of the antibody may be composed of amino acids, where the antibody is a recombinant binding protein or a synthetic peptide, where the recombinant binding protein cross-blocks the binding of the antibody disclosed herein to human APJ. The non-CDR portions of the antibody can be composed of amino acids, where the antibody is a recombinant antibody, and the recombinant antibody exhibits a binding pattern to human APJ peptide in a competitive binding assay similar to that exhibited by at least one of the antibodies L4H4.

[0147] Fusion protein of APJ antibody and Elabela (Elabela fusion protein) In one embodiment, provided herein is an Elabela fusion protein comprising an antibody that specifically binds to APJ and an Elabela fragment.

[0148] In another embodiment, provided herein is an Elabela fusion protein comprising an antibody that specifically binds to APJ, one, two, three, four, five, six, seven or eight Elabela fragments, and a peptide linker (linker); the fusion protein is an Elabela fragment, each of which is independently a forward Elabela fragment or a mutant, linked by its N-terminus to the C-terminus of a heavy or light chain of an APJ antibody through a peptide linker sequence (linker); or the fusion protein is an Elabela fragment, each of which is independently a reverse Elabela fragment or a mutant, linked by its C-terminus to the N-terminus of a heavy or light chain of an APJ antibody.

[0149] In another embodiment, provided herein is an Elabela fusion protein comprising an antibody that specifically binds to APJ, one, two, three or four Elabela fragments, and a peptide linker (linker); the fusion protein links the N-terminus of one Elabela fragment, each Elabela fragment being independently an ordinary Elabela fragment or a mutant, to the C-terminus of the heavy or light chain of one APJ antibody through a peptide linker sequence (linker).

[0150] In another embodiment, provided herein is an Elabela fusion protein comprising an antibody that specifically binds to APJ, one, two, three or four Elabela fragments, and a peptide linker (linker); the fusion protein links the C-terminus of one Elabela fragment, each Elabela fragment being independently a reverse Elabela fragment or a mutant, to the N-terminus of the heavy or light chain of one APJ antibody through a peptide linker sequence (linker).

[0151] In another embodiment, provided herein is an Elabela fusion protein comprising an antibody that specifically binds to APJ, two Elabela fragments, and a peptide linker (linker); the fusion protein links the N-terminus of one Elabela fragment, each Elabela fragment being independently an ordinary Elabela fragment or a mutant, to the C-terminus of the heavy or light chain of one APJ antibody through a peptide linker sequence (linker).

[0152] In another embodiment, provided herein is an Elabela fusion protein comprising an antibody that specifically binds to APJ, two Elabela fragments, and a peptide linker (linker); the fusion protein links the C-terminus of one Elabela fragment, each Elabela fragment being independently a reverse Elabela fragment or a mutant, to the N-terminus of the heavy or light chain of one APJ antibody through a peptide linker sequence (linker).

[0153] In another embodiment, provided herein is an Elabela fusion protein comprising an APJ antibody, two Elabela fragments, and a peptide linker (linker); the fusion protein links the N-terminus of one Elabela fragment to the C-terminus of one APJ antibody light chain: N'-R-linker-Elabela-C'; or the N-terminus of one Elabela fragment to the C-terminus of one APJ antibody heavy chain: N'-R-linker-Elabela-C'; where N' represents the N-terminus of the fusion protein polypeptide chain, C' represents the C-terminus of the fusion protein polypeptide chain, Elabela represents a forward Elabela fragment or mutant, R represents the amino acid sequence of the light or heavy chain of the APJ antibody, and linker represents the peptide linker sequence.

[0154] In another embodiment, provided herein is an Elabela fusion protein comprising an APJ antibody, two Elabela fragments, and a peptide linker (linker); the fusion protein connects the C-terminus of one Elabela fragment to the N-terminus of one APJ antibody light chain through a peptide linker (linker): N'-Elabela-linker-R-C'; or the C-terminus of one Elabela fragment to the N-terminus of one APJ antibody heavy chain: N'-Elabela-linker-R-C'; where N' represents the N-terminus of the fusion protein polypeptide chain, C' represents the C-terminus of the fusion protein polypeptide chain, Elabela represents a reverse Elabela fragment or mutant, R represents the amino acid sequence of the light or heavy chain of the APJ antibody, and linker represents the peptide linker sequence.

[0155] In another embodiment, provided herein is an Elabela fusion protein comprising an APJ antibody, two Elabela fragments, and a peptide linker (linker); the fusion protein connects the N-terminus of one Elabela fragment to the C-terminus of one APJ antibody light chain through a peptide linker (linker): N'-R-linker-Elabela-C'; where N' represents the N-terminus of the fusion protein polypeptide chain, C' represents the C-terminus of the fusion protein polypeptide chain, Elabela represents a forward Elabela fragment or mutant, R represents the APJ antibody light chain amino acid sequence, and linker represents the peptide linker sequence.

[0156] In another embodiment, provided herein is an Elabela fusion protein comprising an APJ antibody, two Elabela fragments, and a peptide linker (linker); the fusion protein connects the N-terminus of one Elabela fragment to the C-terminus of one APJ antibody heavy chain through a peptide linker (linker): N'-R-linker-Elabela-C'; where N' represents the N-terminus of the fusion protein polypeptide chain, C' represents the C-terminus of the fusion protein polypeptide chain, Elabela represents a forward Elabela fragment or mutant, R represents the APJ antibody heavy chain amino acid sequence, and linker represents the peptide linker sequence.

[0157] In one embodiment, the forward Elabela fragment or variant thereof in the Elabela fusion protein provided herein is independently selected from one of the following amino acid sequences: SEQ ID NO:91, SEQ ID NO:92, SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:95, SEQ ID NO:96, SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:100, SEQ ID NO:101, SEQ ID NO:102, SEQ ID NO:103, SEQ ID NO:104, SEQ ID NO:105, SEQ ID NO:106, SEQ ID NO:107, SEQ ID NO:108, SEQ ID NO:109, SEQ ID NO:110, SEQ ID NO:111, SEQ ID NO:112, SEQ ID NO:113, SEQ ID NO:114, SEQ ID NO:115, SEQ ID NO:116, SEQ ID NO:117, SEQ ID NO:118, SEQ ID NO:119, SEQ ID NO:120, SEQ ID NO:121, SEQ ID NO:166 and SEQ ID NO:167.

[0158] In one embodiment, the forward Elabela fragments in the Elabela fusion proteins provided herein are independently selected from one of the following amino acid sequences: SEQ ID NO:92, SEQ ID NO:93, SEQ ID NO:103, SEQ ID NO:107, SEQ ID NO:115, SEQ ID NO:116, SEQ ID NO:166 and SEQ ID NO:167.

[0159] In one embodiment, the reverse Elabela fragment or variant thereof in the Elabela fusion protein provided herein is independently selected from one of the following amino acid sequences: SEQ ID NO:125, SEQ ID NO:126, SEQ ID NO:127, SEQ ID NO:128, SEQ ID NO:129, SEQ ID NO:130, SEQ ID NO:131, SEQ ID NO:132, SEQ ID NO:133, SEQ ID NO:134, SEQ ID NO:135, SEQ ID NO:136, SEQ ID NO:137, SEQ ID NO:138, SEQ ID NO:139, SEQ ID NO:140, SEQ ID NO:141, SEQ ID NO:142, SEQ ID NO:143, SEQ ID NO:144, SEQ ID NO:145, SEQ ID NO:146, SEQ ID NO:147, SEQ ID NO:148, SEQ ID NO:149, SEQ ID NO:150, SEQ ID NO:151, SEQ ID NO:152, SEQ ID NO:153, SEQ ID NO:154 and SEQ ID NO:155.

[0160] In one embodiment, the peptide linker (linker) sequences in the Elabela fusion proteins provided herein independently comprise 1 to 200 amino acid residues, 2 to 100 amino acid residues, 5 to 50 amino acid residues, 6 to 25 amino acid residues, or 10 to 20 amino acid residues.

[0161] In another embodiment, the linker sequence in the Elabela fusion protein provided herein independently comprises a full-length, partial or repeated amino acid sequence of one of the following amino acid sequences: SEQ ID NO:122, SEQ ID NO:123 and SEQ ID NO:124.

[0162] In another embodiment, the linker sequences in the Elabela fusion proteins provided herein are independently selected from the amino acid sequences listed below: SEQ ID NO:122, SEQ ID NO:123 and SEQ ID NO:124.

[0163] In one embodiment, the light chain amino acid sequence of the Elabela fusion protein provided herein is SEQ ID NO: 158, and the heavy chain amino acid sequence is one of the following sequences: SEQ ID NO: 156, SEQ ID NO: 159, SEQ ID NO: 160, SEQ ID NO: 161, SEQ ID NO: 162, SEQ ID NO: 163, SEQ ID NO: 164, and SEQ ID NO: 165. In one embodiment, the light and heavy chain amino acid sequences of the Elabela fusion protein provided herein are SEQ ID NO: 158 and SEQ ID NO: 156, respectively. In another embodiment, the light and heavy chain amino acid sequences of the Elabela fusion protein provided herein are SEQ ID NO: 158 and SEQ ID NO: 159, respectively. In another embodiment, the light and heavy chain amino acid sequences of the Elabela fusion protein provided herein are SEQ ID NO: 158 and SEQ ID NO: 160, respectively. In another embodiment, the light and heavy chain amino acid sequences of the Elabela fusion protein provided herein are SEQ ID NO: 158 and SEQ ID NO: 161, respectively. In another embodiment, the light and heavy chain amino acid sequences of the Elabela fusion protein provided herein are SEQ ID NO: 158 and SEQ ID NO: 162, respectively. In another embodiment, the light and heavy chain amino acid sequences of the Elabela fusion protein provided herein are SEQ ID NO: 158 and SEQ ID NO: 163, respectively. In another embodiment, the light and heavy chain amino acid sequences of the Elabela fusion protein provided herein are SEQ ID NO: 158 and SEQ ID NO: 164, respectively. In a further embodiment, the light and heavy chain amino acid sequences of the Elabela fusion protein provided herein are SEQ ID NO: 158 and SEQ ID NO: 165, respectively.

[0164] nucleic acid In one aspect, the present invention provides isolated nucleic acid molecules. Nucleic acids include, for example, polynucleotides encoding all or part of an Elabela fusion protein, such as one or both chains of an Elabela fusion protein of the present invention or a fragment, derivative, mutein or variant thereof; polynucleotides sufficient for use as hybridization probes; PCR or sequencing primers for identifying, analyzing, mutating or amplifying polynucleotides encoding polypeptides; antisense nucleic acids for inhibiting expression of a polynucleotide and complementary sequences of the above. Nucleic acids can be of any length. The nucleic acid may be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 750, 1,000, 1,500, 3,000, 5,000 or more nucleotides in length, and / or may include one or more additional sequences, e.g., regulatory sequences, and / or may be part of a larger nucleic acid, e.g., a vector. The nucleic acid may be single-stranded or double-stranded and may include RNA and / or DNA nucleotides and artificial variants thereof (e.g., peptide nucleic acids).

[0165] Nucleic acids encoding antibody polypeptides (e.g., heavy or light chains, variable domains only or full length) can be isolated from B cells of mice immunized with APJ antigen. Nucleic acids of antibodies or Elabela fusion proteins can be isolated by conventional procedures such as polymerase chain reaction (PCR).

[0166] Nucleic acid sequences encoding the variable regions of the heavy and light chain variable regions are shown above. One skilled in the art will appreciate that due to the degeneracy of the genetic code, each of the polypeptide sequences disclosed herein is encoded by numerous other nucleic acid sequences. The present invention provides each degenerate nucleotide sequence encoding each antibody or Elabela fusion protein of the present invention.

[0167] The present invention further provides nucleic acids that hybridize to other nucleic acids (e.g., nucleic acids that contain any nucleotide sequence of the Elabela fusion protein) under specific hybridization conditions. Methods for hybridizing nucleic acids are well known in the art. See, for example, (Non-Patent Document 82). As defined herein, for example, moderately stringent hybridization conditions use a hybridization buffer of 5x sodium chloride / sodium citrate (SSC), 0.5% SDS, 1.0 mM EDTA (pH 8.0), about 50% formamide, a pre-wash solution containing 6x SSC and a hybridization temperature of 55°C (or other similar hybridization solutions, such as those containing about 50% formamide at a hybridization temperature of 42°C) and washing conditions of 60°C in 0.5x SSC, 0.1% SDS. Stringent hybridization conditions are hybridization in 6xSSC at 45°C, followed by one or more washes in 0.1xSSC, 0.2% SDS at 68°C. Furthermore, one of skill in the art can manipulate hybridization and / or wash conditions to increase or decrease the stringency of hybridization, such that nucleic acids containing nucleotide sequences that are at least 65, 70, 75, 80, 85, 90, 95, 98 or 99% identical to each other will typically remain hybridized to each other. Basic parameters influencing the selection of hybridization conditions and guidelines for devising suitable conditions are described, for example, by (Non-Patent Document 83); and (Non-Patent Document 84), and can be readily determined by one of skill in the art based, for example, on the length and / or base composition of the DNA. Changes can be introduced into a nucleic acid by mutation, thereby resulting in a change in the amino acid sequence of a polypeptide (e.g., an antibody) that it encodes. Mutations can be introduced using any technique known in the art. In one embodiment, one or more specific amino acid residues are altered, e.g., using a site-directed mutagenesis protocol. In another embodiment, one or more randomly selected residues are altered, e.g., using a random mutagenesis protocol.However it is made, the mutant polypeptide can be expressed and screened for desired properties.

[0168] Mutations can be introduced into a nucleic acid without significantly altering the biological activity of the polypeptide it encodes. For example, nucleotide substitutions can be made to result in amino acid substitutions at non-essential amino acid residues. In one embodiment, the nucleotide sequences provided herein for the Elabela fusion proteins, or fragments, variants or derivatives thereof, are mutated such that they encode the amino acid sequences provided herein for the Elabela fusion proteins, including one or more deletions or substitutions of amino acid residues, resulting in a sequence with two or more different amino acid residues. In another embodiment, mutagenesis inserts an amino acid adjacent to one or more amino acid residues shown herein for the Elabela fusion proteins, resulting in a sequence with two or more different amino acid residues. Alternatively, one or more mutations can be introduced into a nucleic acid that selectively alters the biological activity (e.g., binding to APJ) of the polypeptide it encodes. For example, the mutations can quantitatively or qualitatively alter the biological activity. Examples of quantitative changes include increasing, decreasing or eliminating the activity. Examples of qualitative changes include altering the antigen specificity of the Elabela fusion protein.

[0169] In another aspect, the present invention provides nucleic acid molecules suitable for use as primers or hybridization probes for the detection of nucleic acid sequences of the present invention. The nucleic acid molecules of the present invention may comprise only a portion of a nucleic acid sequence encoding a full-length polypeptide of the present invention, e.g., a fragment that may be used as a probe or primer or a fragment that encodes an active portion of a polypeptide of the present invention (e.g., an APJ-binding portion).

[0170] Probes based on the sequences of the nucleic acids of the invention can be used to detect the nucleic acids or similar nucleic acids, such as transcripts encoding the polypeptides of the invention. The probes can contain label groups, such as radioisotopes, fluorescent compounds, enzymes, or enzyme cofactors. Such probes can be used to identify cells expressing the polypeptides.

[0171] In another aspect, a vector provided herein comprises a nucleic acid encoding a polypeptide of the invention or a portion thereof. Examples of vectors include, but are not limited to, plasmids, viral vectors, non-episomal mammalian vectors, and expression vectors, such as recombinant expression vectors.

[0172] The recombinant expression vectors provided herein may contain the nucleic acids of the invention in a form suitable for expression of the nucleic acid in a host cell. The recombinant expression vector contains one or more control sequences selected based on the host cell to be used for expression, operably linked to the nucleic acid sequence to be expressed. Regulatory sequences include those that direct constitutive expression of a nucleotide sequence in many types of host cells (e.g., the SV40 early gene enhancer, the Rous sarcoma virus promoter, and the cytomegalovirus promoter), those that direct expression of a nucleotide sequence only in certain host cells (e.g., tissue-specific regulatory sequences, see (Non-Patent Document 85), (Non-Patent Document 86), the disclosures of each of which are incorporated herein by reference in their entireties), and those that direct inducible expression of a nucleotide sequence in response to a particular treatment or condition (e.g., the metallothionine promoter in mammalian cells and the tet-responsive and / or streptomycin-responsive promoters in both prokaryotic and eukaryotic cell systems, see ibid.). Those of skill in the art will recognize that the design of the expression vector can depend on such factors as the choice of the host cell to be transformed, the level of expression of protein desired, and the like. The expression vectors of the present invention can be introduced into a host cell to thereby produce a protein or peptide, including a fusion protein or peptide, encoded by a nucleic acid described herein.

[0173] In another aspect, the present invention provides a host cell into which a recombinant expression vector of the present invention has been introduced. The host cell may be any prokaryotic or eukaryotic cell. Prokaryotic host cells include gram-negative or gram-positive bacteria, such as E. coli or Bacillus sp. Higher eukaryotic cells include insect cells, yeast cells and established cell lines of mammalian origin. Examples of suitable mammalian host cell lines include Chinese Hamster Ovary (CHO) cells or their derivatives such as Veggie CHO and related cell lines grown in serum-free medium (see (Non-Patent Document 87)) or the DHFR-deficient CHO line DXB-11 (see (Non-Patent Document 88)). Further CHO cell lines include CHO-K1 (ATCC# CCL-61), EM9 (ATCC# CRL-1861) and W20 (ATCC# CRL-1862). Further host cells include the COS-7 line of monkey kidney cells (ATCC# CRL-1651) (see (Non-Patent Document 89)), L cells, C127 cells, 3T3 cells (ATCC CCL-163), AM-1 / D cells (described in (Patent Document 27)), HeLa cells, the BHK (ATCC CRL-10) cell line, the CV1 / EBNA cell line (ATCC CCL-70) derived from the African green monkey kidney cell line CV1 (see (Non-Patent Document 90)), human embryonic kidney cells such as 293, 293 EBNA or MSR 293, human epidermal A431 cells, human Colo205 cells, other transformed primate cell lines, cell lines derived from in vitro cultures of normal diploid cells, primary tissues, primary transplants, HL-60, U937, HaK or Jurkat cells. Suitable cloning and expression vectors for use with bacterial, fungal, yeast, and mammalian cell hosts are described by Pouwels et al. (Non-Patent Document 91).

[0174] Vector DNA can be introduced into prokaryotic or eukaryotic cells by conventional transformation or transfection techniques. For stable transfection of mammalian cells, it is known that only a small proportion of cells can integrate the foreign DNA into their genome, depending on the expression vector and transfection technique used. To identify and select these integrants, a gene encoding a selectable marker (e.g., for resistance to antibiotics) is generally introduced into the host cells along with the gene of interest. Preferred selectable markers include those that confer resistance to drugs such as G418, hygromycin, and methotrexate. Cells stably transfected with the introduced nucleic acid can be identified by drug selection, among other methods (e.g., cells that have integrated the selectable marker gene will survive, while other cells will die).

[0175] The transformed cells can be cultured under conditions that promote expression of the polypeptide, and the polypeptide is recovered by conventional protein purification procedures. One such purification procedure is described in the Examples below. The polypeptides contemplated for use herein include substantially homogeneous recombinant mammalian APJ antibody or Elabela fusion protein polypeptides that are substantially free of contaminating endogenous substances.

[0176] APJ antibody activity The activity of an APJ antibody refers to the effect of the antibody provided herein in specifically binding to APJ. In one embodiment, the murine or humanized antibody provided herein specifically binds to the human APJ receptor.

[0177] In one embodiment, the K of an antibody provided herein that binds to the human APJ receptor d The K of the antibodies provided herein that bind to the human APJ receptor is in the range of about 0.01 nM to 1000 nM, 0.1 nM to 500 nM, 0.5 nM to 200 nM, 1 nM to 200 nM, or 10 nM to 100 nM. dIn yet another embodiment, the K of the antibodies provided herein that bind to the human APJ receptor ranges from about 1 nM to 200 nM. d In yet another embodiment, the K of the antibodies provided herein that bind to the human APJ receptor ranges from about 1 nM to 100 nM. d is about 1 nM, 2 nM, 5 nM, 10 nM, 20 nM, 30 nM, 40 nM, 50 nM, 60 nM, 70 nM, 80 nM, 90 nM or 100 nM.

[0178] In one embodiment, the antibody provided herein specifically binds to the human APJ receptor and has one or more of the following properties: a. Substantially similar or better K than a reference antibody in binding to the human APJ receptor d To provide; and b. Cross-competitive binding with a reference antibody against the human APJ receptor.

[0179] In one embodiment, the reference antibody comprises a combination of the amino acid sequence of the light chain variable domain SEQ ID NO:62 and the amino acid sequence of the heavy chain variable domain SEQ ID NO:67.

[0180] As used herein, the term "substantially similar" refers to a K d or is about 200%, 180%, 160%, 150%, 140%, 120%, 110%, 100%, 99%, 98%, 97%, 95%, 90%, 85%, 80%, 75%, 70%, 65% or 50% thereof. In one embodiment, the reference antibody comprises a combination of a light chain SEQ ID NO:62 and a heavy chain SEQ ID NO:67.

[0181] Biological activity of APJ antibody and Elabela fusion protein The biological activity of the fusion protein of APJ antibody and Elabela includes the biological activity of Elabela and the activity of APJ antibody. The activity of APJ antibody is as described above. "Biological activity of Elabela" refers to the biological activity of Elabela fusion protein, which binds to and activates Elabela receptor (e.g., APJ) in vivo, and causes intracellular stress response. The cellular stress response includes, but is not limited to, enhancing myocardial contractility, relaxing blood vessels, lowering blood pressure, reducing diuresis (reducing the release of antidiuretic hormones), regulating immune response and release of pituitary-related hormones, and the like. Combining the biological activities of Elabela and APJ antibody, the Elabela fusion protein provided herein can be used to treat various diseases and conditions associated with Elabela and APJ. The fusion protein exerts its biological effect by acting on Elabela and / or APJ, and therefore treatment with the Elabela fusion protein provided herein can be used to treat subjects whose disease or condition would benefit from "enhancing Elabela stimulation". These subjects are referred to as subjects "in need of Elabela stimulation therapy." These subjects include those with acute heart failure, chronic heart failure, pulmonary hypertension and pulmonary arterial hypertension, and further include those with diabetic vasculopathy, heart failure, atrial fibrillation and ischemia-reperfusion injury.

[0182] In one embodiment, the biological activity of the Elabela fusion protein is detected using a reporter gene assay measurement technique to quantify the function of the Elabela fusion protein in activating APJ in vitro.

[0183] In one embodiment, the EC of the antibodies and Elabela fusion proteins provided herein when activating the Elabela / APJ signaling pathway. 50 is in the range of approximately 0.1 nM to 100 nM, 0.5 nM to 20 nM, 1 nM to 10 nM, or 1 nM to 5 nM.

[0184] Pharmaceutical Compositions In one embodiment, a pharmaceutical composition provided herein comprises an Elabela fusion protein provided herein and one or more pharma- ceutically acceptable carriers.

[0185] In one embodiment, the pharmaceutical composition comprises an Elabela fusion protein provided herein and one or more substances selected from the following: a buffer having a pH suitable for the Elabela fusion protein, an antioxidant (e.g., ascorbic acid), a low molecular weight polypeptide (e.g., a polypeptide having less than 10 amino acids), a protein, an amino acid, an example of a sugar (such as dextrin), a complex (e.g., EDTA), glutathione, a stabilizer, and an excipient. In one embodiment, the pharmaceutical composition provided herein may also include a preservative. In one embodiment, the pharmaceutical composition provided herein may be prepared into a lyophilized powder using a suitable excipient solution as a diluent. Further examples of ingredients that can be used in pharmaceutical formulations are given in (Non-Patent Document 92).

[0186] Treatment Method In one embodiment, provided herein is a method for treating, preventing, or ameliorating PAH, comprising administering to a subject a therapeutically effective dose of an Elabela fusion protein provided herein or a pharmaceutical composition thereof.

[0187] In another embodiment, provided herein is a method for treating, preventing, or ameliorating PH, comprising administering to a subject a therapeutically effective dose of an Elabela fusion protein provided herein or a pharmaceutical composition thereof.

[0188] In another embodiment, provided herein is a method for treating, preventing, or ameliorating heart failure, comprising administering to a subject a therapeutically effective dose of an Elabela fusion protein provided herein or a pharmaceutical composition thereof.

[0189] In another embodiment, provided herein is a method for treating, preventing, or ameliorating T2D and its associated metabolic syndrome, comprising administering to a subject a therapeutically effective dose of an Elabela fusion protein provided herein or a pharmaceutical composition thereof.

[0190] In another embodiment, provided herein is a method for treating, preventing or ameliorating two or more of the following diseases: pulmonary hypertension, pulmonary arterial hypertension, type 2 diabetes and its associated metabolic syndrome or heart failure, comprising administering to a subject a therapeutically effective dose of an Elabela fusion protein provided herein or a pharmaceutical composition thereof.

[0191] In any one of the uses provided herein, the pharmaceutical composition provided herein is intended for intravenous or subcutaneous injection.

[0192] The pharmaceutical composition of the Elabela fusion protein may be administered by any suitable technique, for example, but not limited to, parenterally, topically or by inhalation. When injected, the pharmaceutical composition may be administered by rapid injection or continuous infusion, for example via intra-articular, intravenous, intramuscular, intralesional, intraperitoneal or subcutaneous routes. It may be considered, for example, for localized administration at the site of disease or injury, for example, transdermal administration and sustained release implants. Delivery by inhalation includes, for example, nasal or oral inhalation, use of a nebulizer, inhalation of the Elabela fusion protein in aerosol form, etc. Other options include oral formulations, such as pills, syrups or lozenges.

[0193] The dosage and frequency of administration may vary depending on factors such as the route of administration, the particular Elabela fusion protein used, the nature and severity of the disease being treated, whether the condition is acute or chronic, and the size and general condition of the subject. Appropriate dosages may be determined by procedures known in the art, for example in clinical trials, which may include dose escalation studies.

[0194] The Elabela fusion protein provided herein may be administered, for example, once or more than once at regular intervals over a given period of time. In certain embodiments, the Elabela fusion protein is administered once for at least one month or more, for example, for one, two or three months, or indefinitely. To treat chronic diseases, long-term treatment is generally most effective. However, to treat acute diseases, administration over a shorter period of time, for example, one to six weeks, may be sufficient. In general, the Elabela fusion protein is administered until the patient shows a medically relevant degree of improvement over baseline for one or more selected indicators.

[0195] An example of a treatment regimen presented herein involves subcutaneous injection of Elabela fusion protein at an appropriate dosage once per week or more to treat symptoms caused by type 2 diabetes and its associated metabolic syndrome, acute heart failure, chronic heart failure, pulmonary hypertension or pulmonary arterial hypertension. Elabela fusion protein may be administered once per week or once per month until the desired results are achieved, e.g., until the patient's symptoms subside. Treatment may be resumed as needed or a maintenance dose may be administered.

[0196] The patient's BNP or pro-BNP concentration and weight can be monitored before, during and / or after treatment with Elabela fusion protein to detect changes in the patient's pressure. For some diseases, changes in BNP or pro-BNP can change due to factors such as disease progression. BNP or pro-BNP concentrations can be determined using known techniques.

[0197] Particular embodiments of the methods and compositions herein include, for example, the use of an Elabela fusion protein and one or more Elabela agonists, two or more Elabela fusion proteins provided herein, or an Elabela fusion protein provided herein and one or more other Elabela agonists. In further embodiments, the Elabela fusion protein is administered alone or in combination with other agents used to treat the condition the patient suffers from. Examples of these agents include proteinaceous and non-proteinaceous agents. When multiple agents are administered in combination, the dosage should be adjusted accordingly, as is well known in the art. "Combined administration" or combination therapy is not limited to simultaneous administration, but also includes treatment regimens in which the antigen and protein are administered at least once during an administration course that includes administering at least one other therapeutic agent to the patient.

[0198] Meanwhile, a method for preparing a medicament for treating heart failure and pulmonary arterial hypertension and related diseases is provided herein, the medicament comprising a mixture of the Elabela fusion protein provided herein and a pharma- ceutical acceptable excipient for treating related diseases of the above diseases. The method for preparing the medicament is as described above.

[0199] Further provided herein are compositions, kits and methods relating to Elabela fusion proteins that specifically bind to human APJ. Also provided are nucleic acid molecules including polynucleotides encoding all or part of a polypeptide that binds to APJ, as well as derivatives and fragments thereof, such as nucleic acids encoding all or part of an Elabela fusion protein or an Elabela fusion protein derivative. Further provided herein are vectors and plasmids comprising such nucleic acids, and cells and cell lines comprising such nucleic acids and / or vectors and plasmids. Methods provided herein include, for example, methods for preparing, identifying or isolating an Elabela fusion protein that binds to human APJ, methods for determining whether an Elabela fusion protein binds to APJ, and methods for administering an Elabela fusion protein that binds to APJ to an animal model. EXAMPLES

[0200] The technical solutions described herein are further illustrated by the following examples.

[0201] Unless otherwise specified, the starting materials and equipment described herein are either commercially available or commonly used in the art. All methods in the following examples are conventional methods in the art unless otherwise specified.

[0202] 1. Preparation of Antigen for Immunization CHO-DHFR-cells were seeded in 6-well plates. After 24 hours of culture, the cells were transfected with pTM15 plasmid modified to carry the hAPJ gene (see SEQ ID NO:55 for the nucleotide sequence and SEQ ID NO:23 for the amino acid sequence). Transfection was performed by following the transfection conditions recommended by Invitrogen for Lipofectamine2000. 48 hours after transfection, the medium was replaced with complete medium containing 300 μg / mL hygromycin, and then the medium was changed every 3 days. After about 2 weeks of culture, stable clones appeared. The cell colonies were digested and dispersed, and then the cells were passaged and further cultured until the cells grew to 100% cure. The stable cell lines were detected by FACS using V5 labeled antibody (Life Technologies), and the cell population after pressure was identified according to the results of FACS detection. The selected CHO-DHFR-hAPJ cells expressed a large number of hAPJ on the cell membrane. Finally, after subcloning and further identification, three APJ cell lines were selected as high-expressing stable cell lines. These cell lines with high expression of hAPJ can be used as immunogens for antibody preparation (see Example 2).

[0203] Furthermore, the fusion protein of hAPJ extracellular domain and hIgG FC can also be used as an immunogen for antibody preparation. The preparation method is as follows: the fusion protein gene sequence of the extracellular domain of hAPJ, hIgG2 FC and linker was subcloned into pTM5 plasmid. The APJ extracellular domain fusion protein was highly and transiently expressed in suspended HEK293 cells. Then, the cell supernatant was collected and the APJ extracellular domain fusion protein was purified by affinity chromatography.

[0204] 2. Preparation of APJ Antibody Antigen and aluminum hydroxide adjuvant were mixed and injected subcutaneously into BALB / c mice (6-8 weeks old). Mice were boosted once every week. After a total of six immunizations, blood samples were collected by cutting the tail. Serum was then collected by centrifugation, and serum titers were analyzed by FACS. Once acceptable antibody titers were obtained, mice were sacrificed by cervical dislocation, and their spleen cells were collected under sterile conditions. In addition, SP2 / 0 cells were collected in the logarithmic phase of growth, centrifuged, and the cell pellets were resuspended with serum-free medium, then centrifuged and resuspended a second time, and counted. Similar numbers of spleen cells and SP2 / 0 cells were mixed, followed by three wash-centrifugations. After gentle detachment of the cell pellet from the final centrifugation, pre-warmed PEG-1500 was added dropwise, followed by mixing with a pipette, and then 30 mL of pre-warmed serum-free medium was added slowly to terminate the PEG fusion. After centrifugation, the cell pellet was detached, and then fusion medium was added. The spleen cells and feeder layer cells were plated in a 96-well plate, and 100 μL of medium was added to each well. The fused hybridoma cells and feeder layer cells were cultured together in a 96-well plate, and then HAT (sarcin, amethopterin, and thymidine) was selected to remove non-fused cells. After 10 days, the supernatant of the hybridoma cells in the culture plate was collected for ELISA analysis.

[0205] 3. ELISA screening for APJ antibodies CHO-DHFR-hAPJ cells with overexpression of hAPJ and CHO-DHFR- cells without expression of hAPJ were seeded in 96-well plates, respectively. When the cells grew to 90% confluence, the culture supernatant was removed, the attached cells were washed twice with PBS, 100% methanol was added, the cells were fixed at 4°C, then 100 μL of H2O2-PBS was added, followed by incubation at room temperature for 20 min. Then, the cells were washed twice with PBS. After blocking with BSA (dissolved in PBS), the hybridoma supernatant was added and incubated at 4°C for 90 min. After several washes, 100 μL of diluted secondary antibody goat anti-mouse Fc-HRP was added to each well and incubated at 37°C for 30 min. After five washes, 100 μL of TMB chromogenic substrate was added to each well and incubated at 37°C for 15 min, 50 μL of 2M H2SO4 was added to terminate the reaction, and the OD 450 The value was read. After blocking with 1% BSA (dissolved in PBS), the hybridoma supernatant was added and incubated at 4°C for 90 minutes. Then, the above ELISA method was performed to screen anti-hAPJ monoclonal antibodies. The positive control was mouse serum after immunization; the negative control was cell culture supernatant. After initial analysis by ELISA, several positive hybridoma clones secreting anti-hAPJ antibodies were identified. Those hybridoma clones secreting anti-hAPJ antibodies were selected and cloned to obtain stable cell lines secreting anti-hAPJ antibodies. Finally, the affinity of the ascites antibodies secreted by the positive hybridomas was verified and ranked by FACS analysis (see Example 9).

[0206] 4. Cloning and subcloning of the APJ antibody gene Hybridoma cells secreting antibodies were collected. Hybridoma mRNA was extracted according to the manufacturer's protocol of the QIAGEN mRNA extraction kit. The extracted mRNA was then reverse transcribed into cDNA. The reverse transcription primers were specific for mouse light and heavy chain constant regions, the heavy chain reverse transcription primer was (5'-TTTGGRGGGAAGATGAAGAC-3'), and the light chain reverse transcription primer was (5'-TTAACACTCTCCCCTGTTGAA-3') and (5'-TTAACACTCATTCCTGTTGAA-3'). The RT-PCR reaction conditions were as follows: 25°C for 5 min, 50°C for 60 min, and 70°C for 15 min. The reverse transcribed cDNA was diluted with 0.1 mM TE to 500 μL, then added to an ultrafiltration centrifuge tube (Amicon Ultra-0.5) and centrifuged at 2,000 g for 10 min. The filtrate was removed, 500 μL of 0.1 mM TE was added, and centrifuged at 2,000 g for 10 minutes. The filtrate was removed, and the preparation tube was inverted into a new centrifuge tube and centrifuged at 2,000 g for 10 minutes to obtain purified cDNA. After taking the purified cDNA (10 μL) as a template, 4 μL of 5x tailing buffer (Promega), 4 μL of dATP (1 mM) and 10 U terminal transferase (Promega) were added, mixed uniformly, and incubated again at 37°C for 5 minutes and 65°C for 5 minutes. Then, PCR was performed to amplify the genes of the light and heavy chain variable regions of the antibody using the polyA tailed cDNA as a template. All upstream primers were oligo-dT, the heavy chain downstream primers were (5'-TGGACAGGGATCCAGAGTTCC-3') and (5'-TGGACAGGGCTCCATAGTTCC-3'), and the light chain downstream primer was (5'-ACTCGTCCTTGGTCAACGTG-3'). The PCR reaction conditions were as follows: 95°C for 5 min; 95°C for 30 s, 56°C for 30 s, 72°C for 1 min, 40 cycles; and 72°C for 7 min. The PCR products were ligated into PMD 18-T vector (Takara Bio) and then sequenced.PCR primers were then designed based on the DNA sequence of the antibody to ligate the complete light chain, heavy chain signal peptide and variable domains and the mouse IgG1 constant region into the expression vector pTM5.

[0207] 5. Humanization, optimization, and subcloning of APJ antibody Using the NCBI database, the sequences of the light and heavy chain variable regions of the screened mouse antibody were aligned with homologous antibodies, and the germline gene sequences of human antibodies (Ig germline gene sequences) that were homologous to the variable region sequences of the antibodies selected for humanization were searched for, and the human gene sequences with the highest homology except for the CDR sequences were used as templates for CDR grafting to obtain humanized antibody variable region sequences. The genes of the light and heavy chains of the humanized antibody were synthesized and then combined with human IgG2 or IgG4 constant region sequences to obtain the entire recombinant humanized antibody sequence. Expression of the recombinant antibodies was achieved according to Example 8, and their affinity to APJ was analyzed by FACS as described in step 10. The humanized antibody candidates that retained the best affinity to APJ were selected from the group, and their variable region sequences were further modified by site-directed mutagenesis for improved affinity to APJ.

[0208] The optimized heavy and light chain variable region sequences of the humanized antibody were synthesized by a CRO, and the complete heavy chain variable region sequence was further combined with the expression vector pTM5, which was loaded with the heavy chain constant region; similarly, the complete light chain variable region sequence was combined with the expression vector pTM5, which was loaded with the light chain constant region.

[0209] 6. Construction of humanized APJ antibody and Elabela fusion protein The optimized humanized antibody was fused with the Elabela fragment at the C-terminus of the heavy chain to form the Elabela fusion protein. The two sequences were linked by a linker as a bridge. The heavy chain nucleic acid sequence of the humanized APJ antibody was partially linked to the "linker Elabela fragment" by overlap PCR, and the complete fusion protein sequence was ligated into the expression vector pTM5 by adding Nhe1 and Not1 restriction sites to both ends of the primers. After the Elabela fusion protein sequence was ligated into the expression vector pTM5, sequencing analysis was performed to confirm the accuracy of its construction.

[0210] 7. Transient expression of APJ antibody and Elabela fusion protein 5 x 10 of HEK293 or CHO expressing cell lines 5 100 / mL of suspension cells were seeded into shake flasks. After 24 h of rotation at 37°C and 5% CO2, the cell density was 1 × 10 6 The total number of cells / mL was then used for transfection. Polyethylenimine (PEI) was used as a transfection reagent and mixed with DNA during transfection. Both mixtures were incubated for 15 minutes under static conditions and then added to the cell culture. The cells after treatment with the PEI / DNA mixture were rotated at 37°C and 5% CO2 for 24 hours, and then tryptone was added to the cell culture as a supplement required for expression. After completion of expression (>96 hours), the cell supernatant was collected for antibody purification and isolation.

[0211] 8. Purification and isolation of APJ antibody and Elabela fusion protein The collected cell supernatant from Example 8 was centrifuged at 8000 rpm to remove cells and cell debris, and then filtered through a 0.22 μm filter to obtain a clear supernatant for purification. The purification process was carried out through chromatography. First, the supernatant was filtered through an A / G protein-coupled affinity chromatography column, and the antibody or fusion protein was kept in the column after binding to the A / G protein-coupled affinity chromatography column's gland. The antibody or fusion protein was eluted from the chromatography column with an eluent having a pH of 3.0 or less. The collected eluent was immediately neutralized with 1M Tris-HCl. Then, the antibody or fusion protein eluent was dialyzed into PBS or other buffer.

[0212] 9. Verification of functional APJ antibody binding activity through FACS analysis 10 5CHO-DHFR-hAPJ cells were detached and collected in 1.5 mL EP tubes using PBS containing EDTA. The supernatant was removed after centrifugation. Negative control samples were resuspended in FACS loading buffer (PBS, 2% FBS). For positive controls, 200 μL of antibody supernatant at a specific concentration was added to the resuspended cells and then incubated at room temperature; the cells were then centrifuged at 1500 rpm, the supernatant was removed, washed with FACS loading buffer, and centrifuged again. The cells were resuspended, followed by the addition of FITC-labeled goat anti-mouse fluorescent secondary antibody at a dilution of 1:50 (200 μL / well) and incubation for 30 min at room temperature in the dark. After centrifugation, the supernatant was removed and the cells were washed with FACS loading buffer, centrifuged again, and resuspended in loading buffer for analysis. In the experimental results shown in Figures 1A to 1D, the gray peak on the left is the negative control of mouse ascites antibody L1H1 at 500 nM binding to blank cells CHO-DHFR-, and the solid peaks are the binding curves of mouse ascites antibody L1H1 at 500 nM (Figure 1A) and 4 nM (Figure 1B) binding to CHO-DHFR-hAPJ, which are clearly shifted to the right compared to the negative control of the gray peak, indicating specific binding of L1H1 to hAPJ. The gray peak on the right is the negative control of mouse ascites antibody L4H4 at 500 nM binding to blank cell CHO-DHFR-, and the solid peaks are the binding curves of mouse ascites antibody L4H4 at 500 nM (Figure 1C) and 4 nM (Figure 1D) binding to CHO-DHFR-hAPJ, which are clearly shifted to the right compared to the negative control of the gray peak, indicating specific binding of L4H4 to hAPJ.

[0213] 10. In vitro activation of the Elabela / APJ signaling pathway by Elabela and Elabela fusion proteins measured by reporter gene assay 35000 hAPJ-CRE-luciferase expressing CHO-DHFR-cells / well were seeded in 96-well plates and cultured overnight at 37°C. On the second day, the culture supernatant was removed, the cells were washed twice with serum-free medium, and the residual liquid was aspirated. 50 μL of 0.6 μM forskolin was pre-added to the 96-well plate, followed by 50 μL of Elabela fusion protein or Elabela-11 polypeptide diluted in serum-free medium, and incubated for 6 hours at 37°C. After stimulation, 100 μL of Bright Glo chemiluminescent substrate (Promega) was added, then the cell lysate was transferred to a white 96-well plate, and the relative intensity of fluorescence was read with SpectraMax L (Molecular Devices). The data was fitted with prism 5.0 and the EC50 was calculated. The antibodies L1H1 and L4H4 did not block or activate. FIG. 2 shows the activation curves of the Elabela / APJ signaling pathway activated by the fusion protein of L5H5 and linker 2-Elabela-11 and the fusion protein of L5H5 and linker 2-EA5 detected by reporter gene experiments, and the respective EC 50 The EC values ​​were 3.61 nM and 2.55 nM. Figure 3 shows the activation curves of the Elabela / APJ signaling pathway activated by the fusion proteins of L5H5 and linker 2-EA1 and L5H5 and linker 2-EA2, detected by reporter gene experiments. 50 The EC values ​​were 4.95 nM and 2.16 nM. Figure 4 shows the activation curves of the Elabela / APJ signaling pathway activated by the fusion proteins of L5H5 and linker 2-EA3 and L5H5 and linker 2-EA4, detected by reporter gene experiments. 50 were 20.27 nM and 5.43 nM.

[0214] The above examples are provided to fully disclose and explain to one skilled in the art how to make and use the embodiments for which protection is sought, without limiting the scope of the disclosure herein. Modifications obvious to one skilled in the art are within the scope of the claims herein. All publications, patents, and patent applications cited in this specification are incorporated herein by reference as if each publication, patent, or patent application was specifically and individually incorporated herein by reference. The present application provides the following aspects of the invention. (Aspect 1) An antibody that specifically binds to human APJ, comprising one, two, three, four, five, or six amino acid sequences, each of which independently comprises: a. Light chain CDR1 amino acid sequences: SEQ ID NO:10, SEQ ID NO:7, SEQ ID NO:4, and SEQ ID NO:1; b. Light chain CDR2 amino acid sequences: SEQ ID NO:8, SEQ ID NO:5, and SEQ ID NO:2; c. Light chain CDR3 amino acid sequences: SEQ ID NO:11, SEQ ID NO:9, SEQ ID NO:6, and SEQ ID NO:3; d. Heavy chain CDR1 amino acid sequences: SEQ ID NO:18, SEQ ID NO:15, and SEQ ID NO:12; e. Heavy chain CDR2 amino acid sequences: SEQ ID NO:21, SEQ ID NO:19, SEQ ID NO:16, and SEQ ID NO:13; and f. Heavy chain CDR3 amino acid sequences: SEQ ID NO:22, SEQ ID NO:20, SEQ ID NO:17, and SEQ ID NO:14 An antibody selected from the group consisting of (Aspect 2) and one or two amino acid sequences, each amino acid sequence independently comprising: a. Light chain CDR1 amino acid sequences: SEQ ID NO:1, SEQ ID NO:4, SEQ ID NO:7, and SEQ ID NO:10; and b. Heavy chain CDR1 amino acid sequences: SEQ ID NO:12, SEQ ID NO:15, and SEQ ID NO:18 2. The antibody of embodiment 1, selected from: (Aspect 3) and one or two amino acid sequences, each amino acid sequence independently comprising: a. Light chain CDR2 amino acid sequences: SEQ ID NO:2, SEQ ID NO:5, and SEQ ID NO:8; and b. Heavy chain CDR2 amino acid sequences: SEQ ID NO:13, SEQ ID NO:16, SEQ ID NO:19 and SEQ ID NO:21 3. The antibody according to claim 1 or 2, selected from the group consisting of (Aspect 4) and one or two amino acid sequences, each amino acid sequence independently comprising: a. Light chain CDR3 amino acid sequences: SEQ ID NO:3, SEQ ID NO:6, SEQ ID NO:9, and SEQ ID NO:11; and b. Heavy chain CDR3 amino acid sequences: SEQ ID NO:14, SEQ ID NO:17, SEQ ID NO:20 and SEQ ID NO:22 The antibody according to any one of aspects 1 to 3, wherein the antibody is selected from the group consisting of (Aspect 5) The antibody according to any one of Aspects 1 to 4, comprising one or two amino acid sequences, each amino acid sequence independently selected from SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, and SEQ ID NO:11. (Aspect 6) The antibody according to any one of Aspects 1 to 5, comprising one or two amino acid sequences, each amino acid sequence independently selected from SEQ ID NO:12, SEQ ID NO:13, SEQ ID NO:14, SEQ ID NO:15, SEQ ID NO:16, SEQ ID NO:17, SEQ ID NO:18, SEQ ID NO:19, SEQ ID NO:20, SEQ ID NO:21, and SEQ ID NO:22. (Aspect 7) The antibody according to any one of aspects 1 to 6, comprising or further comprising a combination of light chain and heavy chain CDR1 amino acid sequences independently selected from SEQ ID NO:1 and SEQ ID NO:12, SEQ ID NO:4 and SEQ ID NO:15, SEQ ID NO:7 and SEQ ID NO:18, and SEQ ID NO:10 and SEQ ID NO:18. (Aspect 8) The antibody according to any one of aspects 1 to 7, comprising or further comprising a combination of light chain and heavy chain CDR2 amino acid sequences independently selected from SEQ ID NO:2 and SEQ ID NO:13, SEQ ID NO:5 and SEQ ID NO:16, SEQ ID NO:8 and SEQ ID NO:19, and SEQ ID NO:5 and SEQ ID NO:21. (Aspect 9) The antibody according to any one of aspects 1 to 8, comprising or further comprising a combination of light chain and heavy chain CDR3 amino acid sequences independently selected from SEQ ID NO:3 and SEQ ID NO:14, SEQ ID NO:6 and SEQ ID NO:17, SEQ ID NO:9 and SEQ ID NO:20, and SEQ ID NO:11 and SEQ ID NO:22. (Aspect 10) a. a combination of the amino acid sequences of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:12, SEQ ID NO:13 and SEQ ID NO:14; b. A combination of the amino acid sequences of SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:15, SEQ ID NO:16 and SEQ ID NO:17; c. A combination of the amino acid sequences of SEQ ID NO:5, SEQ ID NO:10, SEQ ID NO:11, SEQ ID NO:18, SEQ ID NO:21 and SEQ ID NO:22; and d. Combinations of the amino acid sequences of SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:18, SEQ ID NO:19 and SEQ ID NO:20 The antibody according to any one of aspects 1 to 9, comprising a combination of amino acid sequences selected from: (Aspect 11) a. light chain CDR1 amino acid sequence: SEQ ID NO:1; light chain CDR2 amino acid sequence: SEQ ID NO:2; light chain CDR3 amino acid sequence: SEQ ID NO:3; heavy chain CDR1 amino acid sequence: SEQ ID NO:12; heavy chain CDR2 amino acid sequence: SEQ ID NO:13; and heavy chain CDR3 amino acid sequence: SEQ ID NO:14; b. Light chain CDR1 amino acid sequence: SEQ ID NO:4; light chain CDR2 amino acid sequence: SEQ ID NO:5; light chain CDR3 amino acid sequence: SEQ ID NO:6; heavy chain CDR1 amino acid sequence: SEQ ID NO:15; heavy chain CDR2 amino acid sequence: SEQ ID NO:16; and heavy chain CDR3 amino acid sequence: SEQ ID NO:17; c. light chain CDR1 amino acid sequence: SEQ ID NO:7; light chain CDR2 amino acid sequence: SEQ ID NO:8; light chain CDR3 amino acid sequence: SEQ ID NO:9; heavy chain CDR1 amino acid sequence: SEQ ID NO:18; heavy chain CDR2 amino acid sequence: SEQ ID NO:19; and heavy chain CDR3 amino acid sequence: SEQ ID NO:20; or d. Light chain CDR1 amino acid sequence: SEQ ID NO:10; light chain CDR2 amino acid sequence: SEQ ID NO:5; light chain CDR3 amino acid sequence: SEQ ID NO:11; heavy chain CDR1 amino acid sequence: SEQ ID NO:18; heavy chain CDR2 amino acid sequence: SEQ ID NO:21; and heavy chain CDR3 amino acid sequence: SEQ ID NO:22 The antibody according to any one of aspects 1 to 9, comprising: (Aspect 12) The antibody of embodiment 11, comprising a light chain CDR1 amino acid sequence: SEQ ID NO:10; a light chain CDR2 amino acid sequence: SEQ ID NO:5; a light chain CDR3 amino acid sequence: SEQ ID NO:11; a heavy chain CDR1 amino acid sequence: SEQ ID NO:18; a heavy chain CDR2 amino acid sequence: SEQ ID NO:21; and a heavy chain CDR3 amino acid sequence: SEQ ID NO:22. (Aspect 13) and one or two amino acid sequences, each amino acid sequence independently comprising: a. the amino acid sequences of the light chain variable domain: SEQ ID NO:59, SEQ ID NO:60, SEQ ID NO:61, SEQ ID NO:62 and SEQ ID NO:63; and amino acid sequences which are at least 80%, 85%, 90% or 95% identical to one of the amino acid sequences listed above, and b. Heavy chain variable domain amino acid sequences: SEQ ID NO:64, SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67 and SEQ ID NO:68; and amino acid sequences that are at least 80%, 85%, 90% or 95% identical to one of the amino acid sequences listed above. 13. The antibody according to any one of aspects 1 to 12, wherein the antibody is selected from the group consisting of (Aspect 14) A polynucleotide coding sequence may include one or two polynucleotide sequences, each of which independently comprises: a. a polynucleotide encoding sequence of a light chain variable domain: SEQ ID NO:69, SEQ ID NO:70, SEQ ID NO:71, SEQ ID NO:72, and SEQ ID NO:73; and a polynucleotide sequence that is at least 80%, 85%, 90% or 95% identical to one of the polynucleotide sequences listed above, and b. Polynucleotide encoding sequences of the heavy chain variable domain: SEQ ID NO:74, SEQ ID NO:75, SEQ ID NO:76, SEQ ID NO:77 and SEQ ID NO:78; and polynucleotide sequences that are at least 80%, 85%, 90% or 95% identical to one of the polynucleotide sequences listed above. The antibody according to any one of aspects 1 to 13, wherein the antibody is selected from the group consisting of (Aspect 15) The antibody according to any one of aspects 1 to 14, comprising or further comprising an amino acid sequence independently selected from SEQ ID NO:59, SEQ ID NO:60, SEQ ID NO:61, SEQ ID NO:62 and SEQ ID NO:63. (Aspect 16) 16. The antibody according to any one of aspects 1 to 15, comprising or further comprising an amino acid sequence independently selected from SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 67, and SEQ ID NO: 68. (Aspect 17) The antibody according to any one of Aspects 1 to 16, comprising a combination of amino acid sequences of light chain and heavy chain variable domains independently selected from SEQ ID NO:59 and SEQ ID NO:64, SEQ ID NO:60 and SEQ ID NO:65, SEQ ID NO:61 and SEQ ID NO:66, SEQ ID NO:62 and SEQ ID NO:67, and SEQ ID NO:63 and SEQ ID NO:68. (Aspect 18) and one or two amino acid sequences, each of which is independently a. the amino acid sequences of the light chain constant region: SEQ ID NO:79, SEQ ID NO:80, and SEQ ID NO:81; and b. Heavy chain constant region amino acid sequences: SEQ ID NO:82, SEQ ID NO:83, and SEQ ID NO:84 18. The antibody according to any one of aspects 1 to 17, selected from the group consisting of (Aspect 19) An antibody that specifically binds to human APJ, a. The same or better K for binding to the human APJ receptor compared to a reference antibody provided herein d and b. The APJ antibody cross-competes for binding with a reference APJ antibody on human APJ. An antibody having one or more properties selected from the following: (Aspect 20) 20. The antibody of embodiment 19, which cross-competes for binding with a reference APJ antibody provided herein on the human APJ receptor. (Aspect 21) The antibody according to aspect 19 or 20, wherein the reference APJ antibody comprises an antibody according to any one of aspects 1 to 18. (Aspect 22) The antibody of aspect 21, wherein the reference APJ antibody comprises a combination of the amino acid sequence of the light chain variable region SEQ ID NO: 62 and the amino acid sequence of the heavy chain variable region SEQ ID NO: 67 or a combination of the amino acid sequence of the light chain variable region SEQ ID NO: 63 and the amino acid sequence of the heavy chain variable region SEQ ID NO: 68. (Aspect 23) The antibody according to any one of aspects 1 to 22, which is selected from a mouse antibody, a humanized antibody, a chimeric antibody, a monoclonal antibody, a polyclonal antibody, a recombinant antibody, an antigen-binding antibody fragment, a single-chain antibody, a double-chain antibody, a triple-chain antibody, a quadruple-chain antibody, a Fab fragment, a F(ab')x fragment, a domain antibody, an IgD antibody, an IgE antibody, an IgM antibody, an IgG1 antibody, an IgG2 antibody, an IgG3 antibody, and an IgG4 antibody. (Aspect 24) The antibody according to any one of aspects 1 to 23, which is a mouse APJ antibody or a humanized APJ antibody. (Aspect 25) The antibody according to any one of aspects 1 to 24, which is an APJ monoclonal antibody. (Aspect 26) The K of the antibody d is in the range of about 1 nM to 200 nM or about 1 nM to 100 nM. (Aspect 27) An Elabela fusion protein comprising the APJ antibody according to any one of aspects 1 to 26 and an Elabela fragment. (Aspect 28) An Elabela fusion protein comprising an antibody according to any one of aspects 1 to 26, one, two, three, four, five, six, seven or eight Elabela fragments and a peptide linker (linker), wherein the Elabela fragments, each of which is independently a forward Elabela fragment or a mutant thereof, are linked at their N-terminus to the C-terminus of a heavy or light chain of an APJ antibody; or the Elabela fragments, each of which is independently a reverse Elabela fragment or a mutant thereof, are linked at their C-terminus to the N-terminus of a heavy or light chain of an APJ antibody through the peptide linker sequence (linker). (Aspect 29) 29. The fusion protein according to aspect 27 or 28, comprising an APJ antibody, one, two, three or four Elabela fragments, and a peptide linker (linker); and linking the N-terminus of the Elabela fragment, each Elabela fragment being independently an Elabela fragment or a mutant thereof, to the C-terminus of the heavy or light chain of the APJ antibody through the peptide linker sequence (linker). (Aspect 30) 29. The fusion protein according to aspect 27 or 28, comprising an APJ antibody, one, two, three or four Elabela fragments, and a peptide linker (linker); and linking the C-terminus of the Elabela fragment, each Elabela fragment being independently a reverse Elabela fragment or a mutant thereof, to the N-terminus of the heavy or light chain of the APJ antibody through the peptide linker sequence (linker). (Aspect 31) 29. The fusion protein according to aspect 27 or 28, comprising an APJ antibody, two Elabela fragments, and a peptide linker sequence (linker); and linking the N-terminus of the Elabela fragment, each Elabela fragment being independently an Elabela fragment or a mutant thereof, to the C-terminus of the heavy or light chain of the APJ antibody through the peptide linker sequence (linker). (Aspect 32) 29. The fusion protein according to aspect 27 or 28, comprising an APJ antibody, two Elabela fragments, and a peptide linker sequence (linker); and linking the C-terminus of the Elabela fragment, each Elabela fragment being independently a reverse Elabela fragment or a mutant thereof, to the N-terminus of the heavy chain or light chain of the APJ antibody through the peptide linker sequence (linker). (Aspect 33) The APJ antibody, Elabela fragment and peptide linker sequence were synthesized in the following manner: Linking the N-terminus of the Elabela fragment to the C-terminus of the light chain of the APJ antibody through a peptide linker sequence (linker): N'-R-linker-Elabela-C'; and Linking the N-terminus of the Elabela fragment to the C-terminus of the heavy chain of the APJ antibody through a peptide linker sequence (linker): N'-R-linker-Elabela-C' are fused to form the fusion protein in one of 33. The fusion protein according to any one of aspects 27 to 32, wherein N' represents the N-terminus of the fusion protein polypeptide, C' represents the C-terminus of said fusion protein polypeptide, Elabela represents said Elabela fragment or a mutant thereof, R represents said light or heavy chain amino acid sequence selected from any one of aspects 1 to 26, and linker represents said peptide linker. (Aspect 34) 34. The Elabela fusion protein according to any one of aspects 27 to 33, wherein the peptide linker (linker) sequence comprises an amino acid sequence independently selected from SEQ ID NO:122, SEQ ID NO:123 and SEQ ID NO:124. (Aspect 35) 35. The Elabela fusion protein according to any one of aspects 27 to 34, wherein the peptide linker (linker) comprises SEQ ID NO: 123. (Aspect 36) 36. The Elabela fusion protein according to any one of aspects 27 to 35, wherein the Elabela fragment comprises an amino acid sequence independently selected from SEQ ID NO:91, SEQ ID NO:92, SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:95, SEQ ID NO:96, SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:100, SEQ ID NO:101, SEQ ID NO:102, SEQ ID NO:103, SEQ ID NO:104, SEQ ID NO:105, SEQ ID NO:106, SEQ ID NO:107, SEQ ID NO:108, SEQ ID NO:109, SEQ ID NO:110, SEQ ID NO:111, SEQ ID NO:112, SEQ ID NO:113, SEQ ID NO:114, SEQ ID NO:115, SEQ ID NO:116, SEQ ID NO:117, SEQ ID NO:118, SEQ ID NO:119, SEQ ID NO:120, SEQ ID NO:121, SEQ ID NO:166, and SEQ ID NO:167. (Aspect 37) 37. The Elabela fusion protein according to embodiment 36, wherein the Elabela fragment comprises an amino acid sequence independently selected from SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:103, SEQ ID NO:107, SEQ ID NO:109 and SEQ ID NO:116. (Aspect 38) 38. The Elabela fusion protein according to any one of aspects 27 to 37, wherein the Elabela fragment comprises an amino acid sequence independently selected from SEQ ID NO:125, SEQ ID NO:126, SEQ ID NO:127, SEQ ID NO:128, SEQ ID NO:129, SEQ ID NO:130, SEQ ID NO:131, SEQ ID NO:132, SEQ ID NO:133, SEQ ID NO:134, SEQ ID NO:135, SEQ ID NO:136, SEQ ID NO:137, SEQ ID NO:138, SEQ ID NO:139, SEQ ID NO:140, SEQ ID NO:141, SEQ ID NO:142, SEQ ID NO:143, SEQ ID NO:144, SEQ ID NO:145, SEQ ID NO:146, SEQ ID NO:147, SEQ ID NO:148, SEQ ID NO:149, SEQ ID NO:150, SEQ ID NO:151, SEQ ID NO:152, SEQ ID NO:153, SEQ ID NO:154, and SEQ ID NO:155. (Aspect 39) (i) a combination of the amino acid sequences of SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:18, SEQ ID NO:19 and SEQ ID NO:20; (ii) an amino acid sequence independently selected from SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:103, SEQ ID NO:107, SEQ ID NO:109, and SEQ ID NO:116; and (iii) SEQ ID NO: 123 39. The Elabela fusion protein according to any one of embodiments 27 to 38, comprising: (Aspect 40) A polynucleotide encoding the Elabela fusion protein according to any one of aspects 27 to 39. (Aspect 41) A vector comprising the polynucleotide according to embodiment 40. (Aspect 42) A host cell line comprising the vector of embodiment 41. (Aspect 43) A pharmaceutical composition comprising the antibody according to any one of aspects 1 to 26 and a pharma- ceutically acceptable carrier. (Aspect 44) A pharmaceutical composition comprising an Elabela fusion protein according to any one of aspects 27 to 39 and a pharma- ceutically acceptable carrier. (Aspect 45) 40. Use of an Elabela fusion protein according to any one of aspects 27 to 39 in the preparation of a medicament for treating or preventing pulmonary arterial hypertension. (Aspect 46) 40. Use of an Elabela fusion protein according to any one of embodiments 27 to 39 in the preparation of a medicament for treating or preventing pulmonary hypertension. (Aspect 47) 40. Use of an Elabela fusion protein according to any one of embodiments 27 to 39 in the preparation of a medicament for treating or preventing heart failure. (Aspect 48) 40. Use of an Elabela fusion protein according to any one of aspects 27 to 39 in the preparation of a medicament for the treatment or prevention of type 2 diabetes and its associated metabolic syndrome. (Aspect 49) 40. Use of an Elabela fusion protein according to any one of aspects 27 to 39 in the preparation of a medicament for the treatment or prevention of two or more of the following pathologies: pulmonary arterial hypertension, pulmonary hypertension, type 2 diabetes and its associated metabolic syndrome or heart failure. (Aspect 50) 50. The use according to any one of aspects 45 to 49, wherein the pharmaceutical composition is administered intravenously or subcutaneously.

Claims

1. An antibody that specifically binds to human APJ, Light chain CDR1 amino acid sequence of SEQ ID NO: 10; Light chain CDR2 amino acid sequence of SEQ ID NO:5; Light chain CDR3 amino acid sequence of SEQ ID NO:11; Heavy chain CDR1 amino acid sequence of SEQ ID NO:18; The heavy chain CDR2 amino acid sequence of SEQ ID NO:21; and Heavy chain CDR3 amino acid sequence of SEQ ID NO:22 The antibody comprising:

2. a. the amino acid sequence of the light chain variable domain of SEQ ID NO: 63 and the amino acid sequence of the heavy chain variable domain of SEQ ID NO: 68, or b. The amino acid sequence of the light chain variable domain of SEQ ID NO:62 and the amino acid sequence of the heavy chain variable domain of SEQ ID NO:67 The antibody of claim 1 , comprising:

3. The antibody comprises one or two amino acid sequences, each amino acid sequence independently comprising: a. Light chain constant region amino acid sequences: SEQ ID NO:79, SEQ ID NO:80, and SEQ ID NO:81; and b. Heavy chain constant region amino acid sequences: SEQ ID NO:82, SEQ ID NO:83 and SEQ ID NO:84 The antibody of claim 1 or 2, selected from the group consisting of:

4. The antibody according to any one of claims 1 to 3, which is selected from a murine antibody, a humanized antibody, a chimeric antibody, a monoclonal antibody, a polyclonal antibody, a recombinant antibody, an antigen-binding antibody fragment, a single-chain antibody, a double-chain antibody, a triple-chain antibody, a quadruple-chain antibody, a Fab fragment, an F(ab')x fragment, a domain antibody, an IgD antibody, an IgE antibody, an IgM antibody, an IgG1 antibody, an IgG2 antibody, an IgG3 antibody, and an IgG4 antibody.

5. The antibody of any one of claims 1 to 4, which is a mouse APJ antibody or a humanized APJ antibody.

6. The antibody according to any one of claims 1 to 5, which is an APJ monoclonal antibody.

7. The K of the antibody ｄ The antibody of any one of claims 1 to 6, wherein the antibody has a specific binding affinity to the antibody, and the specific binding affinity is in the range of 1 nM to 200 nM.

8. The K of the antibody ｄ The antibody of claim 7, wherein the antibody has a specific binding affinity to the antibody.

9. An Elabela fusion protein comprising an APJ antibody according to any one of claims 1 to 8 and an Elabela fragment.

10. An Elabela fusion protein comprising an antibody according to any one of claims 1 to 8 and one, two, three, four, five, six, seven or eight Elabela fragments and a peptide linker (linker); and wherein the N-terminus of the Elabela fragment is linked to the C-terminus of a heavy or light chain of an APJ antibody through a peptide linker sequence (linker); each Elabela fragment is independently a forward Elabela fragment or a mutant thereof; or the C-terminus of the Elabela fragment has the N-terminus of the heavy or light chain of an APJ antibody, and each Elabela fragment is independently a reverse Elabela fragment or a mutant thereof.

11. The fusion protein of claim 9 or 10, wherein the fusion protein comprises an APJ antibody and one, two, three, or four Elabela fragments and a peptide linker (linker); and the N-terminus of the Elabela fragment is linked to the C-terminus of the heavy chain or light chain of the APJ antibody through a peptide linker sequence (linker), and each Elabela fragment is independently an Elabela fragment or a mutant thereof.

12. The fusion protein of claim 9 or 10, wherein the fusion protein comprises an APJ antibody and one, two, three, or four Elabela fragments and a peptide linker (linker); and the C-terminus of the Elabela fragment is linked to the N-terminus of the heavy chain or light chain of the APJ antibody through a peptide linker sequence (linker), and each Elabela fragment is independently a reverse Elabela fragment or a mutant thereof.

13. The fusion protein of claim 9 or 10, comprising an APJ antibody and two Elabela fragments and a peptide linker sequence (linker); and the N-terminus of the Elabela fragment is linked to the C-terminus of the heavy chain or light chain of the APJ antibody through the peptide linker sequence (linker), and each Elabela fragment is independently an Elabela fragment or a mutant thereof.

14. The fusion protein of claim 9 or 10, wherein the fusion protein comprises an APJ antibody and two Elabela fragments and a peptide linker sequence (linker); and the C-terminus of the Elabela fragment is linked to the N-terminus of the heavy chain or light chain of the APJ antibody through the peptide linker sequence (linker), and each Elabela fragment is independently a reverse Elabela fragment or a mutant thereof.

15. The APJ antibody, Elabela fragment and peptide linker sequence were synthesized in the following manner: Linking the N-terminus of the Elabela fragment to the C-terminus of the light chain of the APJ antibody through a peptide linker sequence (linker): N'-R-linker-Elabela-C'; and Linking the N-terminus of the Elabela fragment to the C-terminus of the heavy chain of the APJ antibody through a peptide linker sequence (linker): N'-R-linker-Elabela-C' to form the fusion protein, 15. The fusion protein of any one of claims 10 to 14, wherein N' represents the N-terminus of the fusion protein polypeptide, C' represents the C-terminus of the fusion protein polypeptide, Elabela represents the Elabela fragment or a mutant thereof, R represents the light or heavy chain amino acid sequence selected from any one of claims 1 to 8, and linker represents the peptide linker.

16. The Elabella fusion protein according to any one of claims 10 to 15, wherein the peptide linker (linker) sequence comprises an amino acid sequence independently selected from SEQ ID NO: 122, SEQ ID NO: 123 and SEQ ID NO:

124.

17. The Elabella fusion protein according to any one of claims 10 to 16, wherein the peptide linker (linker) comprises SEQ ID NO:

123.

18. 18. The Elabela fusion protein of any one of claims 9 to 17, wherein the Elabela fragment comprises an amino acid sequence independently selected from SEQ ID NO:91, SEQ ID NO:92, SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:95, SEQ ID NO:96, SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:100, SEQ ID NO:101, SEQ ID NO:102, SEQ ID NO:103, SEQ ID NO:104, SEQ ID NO:105, SEQ ID NO:106, SEQ ID NO:107, SEQ ID NO:108, SEQ ID NO:109, SEQ ID NO:110, SEQ ID NO:111, SEQ ID NO:112, SEQ ID NO:113, SEQ ID NO:114, SEQ ID NO:115, SEQ ID NO:116, SEQ ID NO:117, SEQ ID NO:118, SEQ ID NO:119, SEQ ID NO:120, SEQ ID NO:121, SEQ ID NO:166 and SEQ ID NO:

167.

19. The Elabela fusion protein of claim 18, wherein the Elabela fragment comprises an amino acid sequence independently selected from SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:103, SEQ ID NO:107, SEQ ID NO:109 and SEQ ID NO:

116.

20. 20. The Elabela fusion protein of any one of claims 9 to 19, wherein the Elabela fragment comprises an amino acid sequence independently selected from SEQ ID NO:125, SEQ ID NO:126, SEQ ID NO:127, SEQ ID NO:128, SEQ ID NO:129, SEQ ID NO:130, SEQ ID NO:131, SEQ ID NO:132, SEQ ID NO:133, SEQ ID NO:134, SEQ ID NO:135, SEQ ID NO:136, SEQ ID NO:137, SEQ ID NO:138, SEQ ID NO:139, SEQ ID NO:140, SEQ ID NO:141, SEQ ID NO:142, SEQ ID NO:143, SEQ ID NO:144, SEQ ID NO:145, SEQ ID NO:146, SEQ ID NO:147, SEQ ID NO:148, SEQ ID NO:149, SEQ ID NO:150, SEQ ID NO:151, SEQ ID NO:152, SEQ ID NO:153, SEQ ID NO:154 and SEQ ID NO:

155.

21. (i) a combination of the amino acid sequences of SEQ ID NO:10, SEQ ID NO:5, SEQ ID NO:11, SEQ ID NO:18, SEQ ID NO:21 and SEQ ID NO:22; (ii) an amino acid sequence independently selected from SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:103, SEQ ID NO:107, SEQ ID NO:109, and SEQ ID NO:116; and (iii) SEQ ID NO: 123 The Elabela fusion protein of any one of claims 9 to 20, comprising:

22. A polynucleotide encoding an Elabella fusion protein according to any one of claims 9 to 21.

23. A vector comprising the polynucleotide of claim 22.

24. A host cell line comprising the vector of claim 23.

25. A pharmaceutical composition comprising the antibody according to any one of claims 1 to 8.

26. A pharmaceutical composition comprising an Elabela fusion protein according to any one of claims 9 to 21.

27. A pharmaceutical composition comprising an Elabela fusion protein according to any one of claims 9 to 21 for treating or preventing pulmonary arterial hypertension.

28. A pharmaceutical composition comprising an Elabela fusion protein according to any one of claims 9 to 21 for treating or preventing pulmonary hypertension.

29. A pharmaceutical composition comprising an Elabela fusion protein according to any one of claims 9 to 21 for treating or preventing heart failure.

30. A pharmaceutical composition comprising an Elabela fusion protein according to any one of claims 9 to 21 for treating or preventing type 2 diabetes and its associated metabolic syndrome.

31. 22. A pharmaceutical composition comprising an Elabela fusion protein according to any one of claims 9 to 21 for treating or preventing two or more of the following pathologies: pulmonary arterial hypertension, pulmonary hypertension, type 2 diabetes and its associated metabolic syndrome, or heart failure.

32. The pharmaceutical composition according to any one of claims 27 to 31, which is administered intravenously or subcutaneously.

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