An antibody against respiratory syncytial virus and its application

Abstract

This disclosure provides an antibody or antigen-binding fragment thereof that binds to the respiratory syncytial virus (RSV) F protein. This disclosure also provides the use of the antibody or antigen-binding fragment thereof in the preparation for the treatment and / or prevention of RSV infection.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese patent application No. 202110653393.6, filed with the Chinese Patent Office on June 11, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to antibodies or antigen-binding fragments thereof that bind to the respiratory syncytial virus (RSV) F protein. This disclosure also relates to the use of such antibodies or antigen-binding fragments thereof in the preparation for the treatment and / or prevention of RSV infection. Background Technology

[0004] Respiratory syncytial virus (RSV) causes acute lower respiratory tract infections and is a leading cause of illness and death in children worldwide. The hospitalization rate for RSV-related illnesses is three times higher than that for influenza or parainfluenza virus-related illnesses. High hospitalization rates are common in infants under 5 years old, with the highest incidence in 3-year-olds. RSV accounts for 6.7% of infant deaths between 1 month and 1 year of age globally, making it the most common respiratory infection pathogen in preschool children, especially infants. Immunized adults and the elderly are also susceptible. Despite the serious threat RSV poses to global health, there are few preventative and treatment measures for RSV infection, and vaccine development has been hampered by the worsening of symptoms caused by formalin-inactivated vaccines. Maternal antibodies are passed to the infant through the placenta in the last few weeks of pregnancy, providing protective immunity, but this protection diminishes by about two times each month and has poor durability. Currently, there are no vaccines or specific treatments for RSV infection. The only preventative measure is palizumab, approved in 1998. While it can reduce hospitalization and mortality rates in infants to some extent, its immunomodulatory activity is poor, and it requires frequent administration. Premature infants with congenital respiratory and circulatory system disorders need five immunizations throughout the epidemic season. This high cost and inconvenience make it unsuitable for all infants and limit its use for high-risk infants. Furthermore, AstraZeneca's improved version of the monoclonal antibody D25, MEDI8897, has stronger neutralizing activity and requires only 1-2 immunizations. It is currently in phase III clinical trials. Therefore, there is an urgent need for highly effective next-generation monoclonal antibody drugs for the prevention / treatment of RSV infection.

[0005] To date, neutralizing antibodies have proven to be an effective treatment for viral diseases. Currently marketed drugs for the treatment and prevention of viral infections include palivizumab (Synagis) for the prevention of respiratory syncytial virus (RSV) infection in children, elbalizumab (Trogarzo) for the treatment of HIV infection, and rabishield for post-exposure prophylaxis against rabies. In addition, several monoclonal antibodies targeting different viruses are in different stages of clinical trials (https: / / clinicaltrials.gov / ). Antibodies primarily function in two ways. First, neutralizing antibodies can block viral infection by binding to viral envelope proteins, thus blocking the binding of the virus to cell receptors. Second, antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) can recruit immune cells and molecules such as macrophages or complement receptors, thereby clearing free viruses and infected cells.

[0006] Respiratory syncytial virus (RSV) belongs to the Paramyxoviridae family and is a single-stranded, negative-sense RNA virus with two antigenic serotypes, A and B, both of which are prevalent. The adsorption protein (G) and fusion protein (F) on the RSV surface are the main antigens capable of inducing neutralizing antibody responses. The G protein is responsible for viral adhesion to the cell membrane surface, but it exhibits antigenic variability, making it difficult to develop broad-spectrum protective drugs. The F protein is responsible for viral fusion with the cell and exhibits more neutralizing antibody targeting epitopes, making it the main target for most vaccines and immunotherapies currently under development, and also the target for the clinical use of palivizumab to prevent RSV disease. The F protein has two conformations: pre-fusion and post-fusion. The pre-fusion F protein is unstable and undergoes conformational inversion, becoming the post-fusion F protein. Currently, most strong neutralizing epitopes have been found to be concentrated in the pre-fusion conformation of the F protein; for example, the monoclonal antibody D25 and its improved version, MEDI8897, bind to the pre-fusion F protein. Epitope. In 2013, Peter Kwong's team obtained a stable pre-fusion RSV F protein, DS-Cav1, by introducing a set of mutations (S190F, V207, S155C, and S290C). Immunization of mice with DS-Cav1 activated higher levels of neutralizing antibodies. Summary of the Invention

[0007] On the one hand, this disclosure provides an antibody or antigen-binding fragment thereof that binds to the respiratory syncytial virus F protein, comprising a heavy chain variable region, wherein the HCDR1, HCDR2, and HCDR3 of the heavy chain variable region are selected from one of the following combinations:

[0008] (1) The amino acid sequence of HCDR1 is: GFTFSSYA (SEQ ID NO: 18);

[0009] The amino acid sequence of HCDR2 is: ISYDGSNT (SEQ ID NO: 19);

[0010] The amino acid sequence of HCDR3 is: ARDYCSRGTCYHDY (SEQ ID NO: 20);

[0011] (2) The amino acid sequence of HCDR1 is: GYTFTTYD (SEQ ID NO: 24);

[0012] The amino acid sequence of HCDR2 is: LNPDNGNT (SEQ ID NO: 25);

[0013] The amino acid sequence of HCDR3 is: TRAPWWWYFDY (SEQ ID NO: 26); and

[0014] (3) The amino acid sequence of HCDR1 is: GFSFTNYG (SEQ ID NO: 30);

[0015] The amino acid sequence of HCDR2 is: ISYDDGSDK (SEQ ID NO: 31);

[0016] The amino acid sequence of HCDR3 is: VRDPTGDY (SEQ ID NO: 32).

[0017] In some embodiments, the antibody or its antigen-binding fragment as described above further includes a light chain variable region, wherein the HCDR1, HCDR2, and HCDR3 of the heavy chain variable region and the LCDR1, LCDR2, and LCDR3 of the light chain variable region are selected from one of the following combinations:

[0018] (1) The amino acid sequence of LCDR1 is: QDIRND (SEQ ID NO: 15);

[0019] The amino acid sequence of LCDR2 is: AAS (SEQ ID NO: 16);

[0020] The amino acid sequence of LCDR3 is: LQDYNYPQTFG (SEQ ID NO: 17);

[0021] The amino acid sequence of HCDR1 is: GFTFSSYA (SEQ ID NO: 18);

[0022] The amino acid sequence of HCDR2 is: ISYDGSNT (SEQ ID NO: 19);

[0023] The amino acid sequence of HCDR3 is: ARDYCSRGTCYHDY (SEQ ID NO: 20);

[0024] (2) The amino acid sequence of LCDR1 is: SGSIASNY (SEQ ID NO: 21);

[0025] The amino acid sequence of LCDR2 is: EDN (SEQ ID NO: 22);

[0026] The amino acid sequence of LCDR3 is: QSYDTSNAVFG (SEQ ID NO: 23);

[0027] The amino acid sequence of HCDR1 is: GYTFTTYD (SEQ ID NO: 24);

[0028] The amino acid sequence of HCDR2 is: LNPDNGNT (SEQ ID NO: 25);

[0029] The amino acid sequence of HCDR3 is: TRAPWWWYFDY (SEQ ID NO: 26); and

[0030] (3) The amino acid sequence of LCDR1 is: SLNIGSNY (SEQ ID NO: 27);

[0031] The amino acid sequence of LCDR2 is: KNN (SEQ ID NO: 28);

[0032] The amino acid sequence of LCDR3 is: AAWDDSLSGVVFG (SEQ ID NO: 29);

[0033] The amino acid sequence of HCDR1 is: GFSFTNYG (SEQ ID NO: 30);

[0034] The amino acid sequence of HCDR2 is: ISYDDGSDK (SEQ ID NO: 31);

[0035] The amino acid sequence of HCDR3 is: VRDPTGDY (SEQ ID NO: 32).

[0036] In some embodiments, the antibody or antigen-binding fragment thereof as described in any of the preceding embodiments, wherein the heavy chain variable region comprises the sequence shown in SEQ ID NO: 4, 6 or 8 or comprises an amino acid sequence having at least 90% sequence identity with the sequence shown in SEQ ID NO: 4, 6 or 8.

[0037] In some embodiments, the antibody or antigen-binding fragment thereof as described in any of the preceding embodiments, wherein the heavy chain variable region comprises the sequence shown in SEQ ID NO: 4 or comprises an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 4, and the light chain variable region comprises the sequence shown in SEQ ID NO: 5 or comprises an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 5; or

[0038] The heavy chain variable region includes the sequence shown in SEQ ID NO: 6 or includes an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 6; the light chain variable region includes the sequence shown in SEQ ID NO: 7 or includes an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 7; or

[0039] The heavy chain variable region includes the sequence shown in SEQ ID NO: 8 or includes an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 8, and the light chain variable region includes the sequence shown in SEQ ID NO: 9 or includes an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 9.

[0040] In some embodiments, the antibody or antigen-binding fragment thereof as described in any of the preceding embodiments, wherein the heavy chain constant region comprises the sequence shown in SEQ ID NO: 10 or comprises an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 10; and the light chain constant region of the antibody comprises the sequence shown in SEQ ID NO: 11 or 12 or comprises an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 11 or 12.

[0041] In some embodiments, the antibody or antigen-binding fragment thereof as described in any of the preceding embodiments is a murine antibody, a chimeric antibody, a human antibody, or a fully human antibody; preferably, the antibody is a human antibody.

[0042] In some embodiments, the antibody or its antigen-binding fragment as described in any of the preceding embodiments is wherein the F protein is in a pre-fusion conformation.

[0043] In some embodiments, the respiratory syncytial virus is type A or type B respiratory syncytial virus.

[0044] On the other hand, this disclosure provides nucleic acid molecules that encode antibodies or antigen-binding fragments thereof as described in any of the preceding claims. Specifically, the nucleic acid molecule encodes a light chain, heavy chain, light chain variable region, or heavy chain variable region of the antibody as described in any of the preceding claims. Furthermore, this disclosure provides expression vectors comprising the aforementioned nucleic acid molecules.

[0045] On the other hand, this disclosure provides a host cell that includes or expresses the above-described antibody or its antigen-binding fragment, or includes the above-described nucleic acid molecule or expression vector.

[0046] On the other hand, this disclosure provides pharmaceutical compositions comprising the antibody or antigen-binding fragment thereof as described in any of the preceding claims, and one or more pharmaceutically acceptable carriers, diluents, buffers or excipients.

[0047] On the other hand, this disclosure provides the use of the antibody or antigen-binding fragment thereof as described in any of the preceding claims in the preparation of a medicament for treating and / or preventing respiratory syncytial virus-related diseases or conditions. On the other hand, this disclosure provides a method for treating and / or preventing respiratory syncytial virus-related diseases or conditions in a subject, comprising administering the subject a therapeutically effective amount of the antibody or antigen-binding fragment thereof as described in any of the preceding claims or the aforementioned pharmaceutical composition.

[0048] Furthermore, the respiratory syncytial virus-related diseases or conditions described in any of the preceding claims are diseases or conditions related to upper respiratory tract infections or lower respiratory tract infections; more preferably, the diseases or conditions are selected from tracheitis, bronchitis, and pulmonary infectious diseases; most preferably, the diseases or conditions are bronchitis or pneumonia.

[0049] On the other hand, this disclosure provides a method for detecting the presence or content of respiratory syncytial virus in a sample, including contacting the sample with the aforementioned antibody or its antigen-binding fragment, and detecting whether an antigen-antibody complex is formed or the amount of the antigen-antibody complex formed.

[0050] On the other hand, this disclosure provides a respiratory syncytial virus detection kit, which includes an antibody or an antigen-binding fragment thereof as described in any of the preceding claims. Attached Figure Description

[0051] Figure 1 The results of chromatography and SDS-PAGE analysis of the expressed and purified RSV-F(DS-Cav1) protein are shown. Detailed Implementation

[0052] Unless otherwise stated, all technical and scientific terms used in this disclosure have the meanings commonly understood by one of ordinary skill in the art.

[0053] "Antibody" refers to an immunoglobulin secreted by plasma cells (effector B cells) and used by the body's immune system to neutralize foreign substances (peptides, viruses, bacteria, etc.). This foreign substance is correspondingly called an antigen. The term "antibody" is used in the broadest sense and encompasses various antibody structures, including but not limited to monoclonal antibodies, polyclonal antibodies; monospecific antibodies, multispecific antibodies (e.g., bispecific antibodies); full-length antibodies and antibody fragments (or antigen-binding fragments, or antigen-binding portions), as long as they exhibit the desired antigen-binding activity. The basic structure of a classic or common antibody molecule is a tetramer composed of two identical heavy chains and two identical light chains. Based on the conservation of amino acid sequences, the heavy and light chains are divided into a variable region (V) at the amino terminus and a constant region (C) at the carboxyl terminus. The interaction of the variable regions of one heavy chain and one light chain forms the antigen-binding site (Fv). Within the variable region, the composition and order of amino acid residues in certain areas are more variable than in other areas (backbone regions, FR), and these are called hypervariable regions (HVR). The hypervariable region is actually the key site for antibody-antigen binding. Because these hypervariable regions are complementary to the antigenic determinants, they are also called complementarity-determining regions (CDRs). Both the heavy and light chains have three CDRs, designated HCDR1, HCDR2, HCDR3 and LCDR1, LCDR2, LCDR3, respectively. Each VH and VL can be composed of three CDRs and four FR regions, arranged in the following order from the amino terminus to the carboxyl terminus: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4.

[0054] When the antibody complementarity-determining region (CDR) sequence is known, those skilled in the art can readily replace portions of the antibody molecule's sequence (e.g., the constant region or backbone region) with sequences from other species, for example, through DNA recombination techniques, to form chimeric antibodies that substantially retain the binding specificity of their source antibody. For instance, when the source antibody is a mouse antibody, its constant region can be replaced with a human antibody constant region, or conversely, when the source antibody is a human antibody, its constant region can be replaced with a mouse antibody constant region to reduce the immunogenicity of the antibody when used in different species or to utilize the specific function of the constant region, such as ADCC-related activity. For further reduction of antibody immunogenicity or other purposes, sequences in the antibody molecule other than the CDR sequence can be replaced with corresponding sequences (which may include one or more amino acid mutations) from another antibody molecule (from the same or different species), while substantially retaining the binding specificity of its source antibody. In a specific instance, those skilled in the art often use CDR transplantation to humanize mouse antibodies.

[0055] Those skilled in the art will also understand that, based on the specific antibody sequence provided in this disclosure, corresponding variants of the anti-F protein antibody molecule provided in this invention can be obtained by replacing, deleting, or adding a few amino acids and verifying or screening the binding ability or biological activity of the resulting product with the corresponding antigen (F protein). These variants should also be included within the scope of this invention.

[0056] Therefore, in some embodiments, the heavy chain variable region of the antibody molecule provided in this disclosure includes the sequence shown in SEQ ID NO:4 or includes an amino acid sequence that is at least 85% (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%) identical to the sequence in SEQ ID NO:4, and the light chain variable region includes the sequence shown in SEQ ID NO:5 or includes an amino acid sequence that is at least 85% (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%) identical to the sequence in SEQ ID NO:5.

[0057] In some embodiments, the heavy chain variable region of the antibody molecule provided in this disclosure includes the sequence shown in SEQ ID NO: 6 or includes an amino acid sequence that is at least 85% (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%) identical to SEQ ID NO: 6.

[0058] The light chain variable region includes the sequence shown in SEQ ID NO: 7 or includes an amino acid sequence that is at least 85% (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%) identical to SEQ ID NO: 7.

[0059] In some embodiments, the heavy chain variable region of the antibody molecule provided in this disclosure includes the sequence shown in SEQ ID NO: 8 or includes an amino acid sequence that is at least 85% (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%) identical to SEQ ID NO: 8, and the light chain variable region includes the sequence shown in SEQ ID NO: 9 or includes an amino acid sequence that is at least 85% (e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%) identical to SEQ ID NO: 9.

[0060] An antibody's "antigen-binding fragment" refers to a polypeptide that includes a portion of the source antibody's sequence (especially the CDR sequence) and possesses the specificity for binding to the source antibody. This antigen-binding fragment typically includes both the light chain variable region and the heavy chain variable region of the source antibody, thus enabling antigen binding. Antigen-binding fragments come in various forms, such as Fab, F(ab')2, single-chain antibodies (scFv), and single-domain antibodies (sdAb). scFv is composed of the antibody's heavy chain variable region and light chain variable region linked together by a short peptide chain. Through proper folding, the variable regions from the heavy and light chains interact non-covalently to form the Fv segment, thus allowing scFv to retain its antigen-binding activity relatively well. sdAb was first discovered in camels; it naturally lacks a light chain but still possesses antigen-binding ability. sdAb has several advantages over ordinary antibody molecules, such as better stability (resistance to pH, heat, and proteases) and the ability to target and bind to antigenic epitopes that are difficult for ordinary antibody molecules to access.

[0061] The "specific binding of an antibody to an antigen" or "antigen-binding specificity" of an antibody refers to its ability to bind to a target antigen with a higher or greater affinity than other antigens. The binding ability of an antibody to a target antigen can be qualitatively or quantitatively determined by various methods, such as measuring the KD value of the antibody-target antigen binding, or determining the antibody's ability to compete with other antibodies for binding to the target antigen. Here, Kd is the equilibrium dissociation constant, which can be used to measure the strength of the binding affinity between the antibody and its antigen. The smaller the KD value, the stronger the affinity. The specific binding of an antibody to a target antigen does not mean that it cannot bind to other antigens; for example, immune cross-reactivity is known in the art.

[0062] When used in this disclosure, "antibody" may include a complete antibody or its antigen-binding fragment, and may be a human antibody, mouse antibody, humanized antibody, chimeric antibody, etc. Antibodies may be of any type, such as IgG, IgE, IgM, IgD, IgA, or IgY, or any subclass, such as IgG1, IgG2, IgG3, IgG4, IgA1, or IgA2, etc.

[0063] Methods for preparing antibodies are known in the art, including but not limited to isolating cells expressing specific antibodies after immunizing animals with antigens (e.g., preparing antibodies via hybridoma technology), screening antibodies using phage antibody libraries, and transforming cells to express antibody molecules through genetic engineering. In one specific example, embodiments of this disclosure provide a method for preparing antibody molecules by introducing a recombinant expression vector encoding antibody heavy and light chains into 293T cells.

[0064] The term "chimeric" antibody refers to an antibody in which a portion of the heavy and / or light chain is derived from a specific source or species, while the remaining portion of the heavy and / or light chain is derived from another different source or species.

[0065] The term "humanized" antibody refers to an antibody that retains the reactivity of a non-human antibody while exhibiting lower immunogenicity in humans. For example, this can be achieved by retaining the non-human CDR region and replacing the rest of the antibody with its human counterpart (i.e., the frame region portion of the constant region and the variable region).

[0066] The terms "human antibody," "human-derived antibody," "fully human antibody," and "completely human antibody" are used interchangeably, referring to antibodies whose variable and constant regions are human sequences. This term encompasses antibodies derived from human genes but with sequence alterations, such as reduced potential immunogenicity, increased affinity, or the elimination of cysteine ​​residues or glycosylation sites that might cause undesirable folding. This term also encompasses antibodies recombined in non-human cells (which may confer glycosylations not characteristic of human cells). The term also includes antibodies that have been fed to transgenic mice containing some or all human immunoglobulin heavy and light chain loci. The meaning of "human antibody" explicitly excludes humanized antibodies containing non-human antigen-binding residues.

[0067] The term "monoclonal antibody" refers to a group of substantially homogeneous antibodies, meaning that the antibody molecules contained in this group have the same amino acid sequence, except for the possible small number of naturally occurring mutations. In contrast, polyclonal antibody formulations typically contain multiple different antibodies with different amino acid sequences in their variable structural domains, and they generally specifically target different epitopes. "Monoclonal" indicates the characteristic of an antibody obtained from a substantially homogeneous group of antibodies and should not be construed as requiring the antibody to be produced by any particular method. In some embodiments, the antibodies provided in this disclosure are monoclonal antibodies.

[0068] The term "antigen" refers to a molecule or molecular moiety that can be bound by a selective binder, such as an antigen-binding protein (including, for example, an antibody), and is further capable of being used in animals to produce antibodies that can bind to that antigen. An antigen may have one or more epitopes that can interact with different antigen-binding proteins (e.g., antibodies).

[0069] It is known in the art that antibody molecules can be modified in various ways, such as PEGylation, glycosylation, forming antibody conjugates (e.g., ADCs), adding purification tags, or fusing with other proteins, for example, to form bispecific antibodies. These antibody derivatives obtained by modifying the antibody molecules provided in this disclosure should also be covered within the scope of this invention.

[0070] When referring to amino acid sequences, the term "sequence identity" (also known as "sequence uniformity") refers to the degree of similarity between two amino acid sequences (e.g., a query sequence and a reference sequence), typically expressed as a percentage. Generally, sequence alignment is performed and gaps (if any) are introduced before calculating the percentage of similarity between two amino acid sequences. If amino acid residues in the two sequences are identical at a given alignment position, the two sequences are considered identical or matched at that position; if amino acid residues are different, they are considered inconsistent or mismatched at that position. In some algorithms, sequence identity is obtained by dividing the number of matched positions by the total number of positions in the alignment window. In other algorithms, the number of gaps and / or gap length are also taken into account. For the purposes of this invention, the publicly available alignment software BLAST (available at ncbi.nlm.nih.gov) can be used to obtain the optimal sequence alignment and calculate the sequence identity between the two amino acid sequences using default settings.

[0071] An "expression vector," also known as a "recombinant expression vector," refers to a nucleic acid molecule containing various expression elements for expressing a target protein (such as the light and / or heavy chains of an antibody molecule) in a host cell. For expression vectors used to express the target protein in eukaryotic cells (mammalian cells, insect cells, plant cells, etc.), these expression elements typically include promoters, enhancers, and polyadenylation signal sequences. To facilitate amplification in *E. coli*, expression vectors often also include *E. coli* replicon sequences. Expression vectors may also include antibiotic resistance genes or selection marker genes for screening (such as the ampicillin resistance gene (AmpR), thymidine kinase gene (TK), etc.) and multiple cloning sites (MCS) for inserting the target protein coding sequence. Expression vectors can be plasmid vectors or viral vectors.

[0072] The expression vectors provided in this disclosure are suitable for expressing the antibody molecules or fragments thereof in a variety of host cells, and are particularly suitable for expression in mammalian cells (e.g., mouse, rat, pig, sheep, monkey, chimpanzee, or human cells). In some embodiments, the mammalian cells may be selected from CHO cells, HEK293 cells, or BHK cells.

[0073] This disclosure utilizes the pre-fusion conformation of the RSV F protein DS-Cav1 as bait to isolate four human monoclonal antibodies from peripheral blood lymphocytes (PBMCs) of children who have recovered from RSV infection using single-cell sequencing technology. These antibodies are named RV7, RV8, RV10, and RV11. Three of these antibodies bind to the RSV F protein: RV8 and RV10 bind to both the pre-fusion and post-fusion F proteins; RV11 binds only to the pre-fusion F protein. These three monoclonal antibodies can be used for the diagnosis and antigen quantification of RSV. Two of these antibodies, RV8 and RV11, exhibit neutralizing activity against both RSV types A and B, and can be used for the prevention and treatment of RSV.

[0074] The antibodies or antigen-binding fragments provided in this disclosure specifically bind to the respiratory syncytial virus (RSV) F protein (pre-fusion conformation and / or post-fusion conformation), i.e., the RSV F protein serves as the target antigen of the antibody. After binding to the RSV F protein, the antibody inhibits RSV's cellular infectivity through neutralizing activity. Therefore, the antibodies or antigen-binding fragments provided in this disclosure can be used for the prevention or treatment of RSV infection. On the other hand, due to the antigen-binding specificity of the antibodies provided in this disclosure, they can be used to detect the presence of RSV virus in samples (such as blood) from a subject. Accordingly, this disclosure provides RSV detection kits that may include the antibodies or antigen-binding fragments provided in this disclosure.

[0075] When referring to pharmaceutical compositions, the term "pharmaceuticalally acceptable carrier" refers to substances such as solid or liquid diluents, fillers, antioxidants, and stabilizers that can be safely administered to humans and / or animals without excessive adverse side effects, and which are suitable for maintaining the activity of the drug or active agent contained therein.

[0076] The term "subject" or "individual" includes both humans and non-human animals. Non-human animals include all vertebrates (e.g., mammals and non-mammals) such as non-human primates (e.g., cynomolgus monkeys), sheep, dogs, cattle, chickens, amphibians, and reptiles. Unless otherwise specified, the terms "patient" or "subject" are used interchangeably in this disclosure. In some embodiments, the individual or subject is a human being.

[0077] "Administration" or "giving," when applied to animals, humans, experimental subjects, cells, tissues, organs, or biological fluids, refers to the contact between an exogenous drug, therapeutic agent, diagnostic agent, or composition and the animal, human, subject, cell, tissue, organ, or biological fluid.

[0078] When referring to the treatment or prevention of RSV infection, "therapeutic effective amount" means an amount of an active compound (such as an antibody) sufficient to elicit a biological or medical response in a subject as desired by a clinician, or an amount of a drug or agent sufficient to achieve or at least partially achieve the intended effect. The "therapeutic effective amount" of the antibody provided in this disclosure can be determined by those skilled in the art based on factors such as the route of administration, the subject's weight, age, and condition. For example, a typical daily dose range can be from 0.01 mg to 100 mg of the active ingredient per kg of body weight.

[0079] As used in this disclosure, the singular forms of “a,” “an,” and “the” include plural references, and vice versa, unless the context clearly indicates otherwise.

[0080] The present invention will be further illustrated by specific embodiments below.

[0081] Example 1: Expression and purification of RSV pre-fusion F protein (DS-Cav1)

[0082] The C-terminus of the pre-fusion F protein DS-Cav1, encoding the RSV A2 strain, was modified by adding a Thrombin restriction site, six histidine sequences, one GS [glycine-serine] linker sequence, one sequence encoding the Strep II tag, and one stop codon (amino acid sequence as shown in SEQ ID NO: 1). These were then inserted into the EcoRI and XhoI restriction sites of the mammalian expression vector pCAGGS. The ligation product was transformed into DH5α competent E. coli cells. Single colonies were then picked and inoculated into 4 mL of LB medium and cultured for 6–8 hours; subsequently, they were transferred to 300 mL of LB medium and cultured for 12–16 hours. The cells were collected, and the plasmid was extracted using the endotoxin-free plasmid extraction kit (TIANGEN) to obtain pCAGGS-RSV-F(DS-Cav1).

[0083] The extracted plasmid pCAGGS-RSV-F (DS-Cav1) was transfected into 293T cells to express the F protein. Four to five days post-transfection, the 293T cell culture supernatant containing the target protein was centrifuged and filtered (0.22 μM) to remove cell debris. The supernatant was then bound to a HisTrapHP (GE Healthcare) nickel chelate column, followed by elution with different concentrations of imidazole. Eluted proteins were collected, and SDS-PAGE results were used to determine the samples containing the target protein.

[0084] The elution peak containing the target protein was collected, concentrated, and then subjected to molecular sieve chromatography. The size and purity of the target protein were determined based on the peak position and SDS-PAGE results (see molecular sieve and SDS-PAGE results). Figure 1Molecular sieving results showed that the protein elution peak was located at 60-70 mL, consistent with the theoretical molecular weight of the F protein trimer, 150 kDa. SDS-PAGE results showed that the F protein elution peak was within the range of ~50 mL under both reducing (+DTT) and non-reducing (-DTT) conditions.

[0085] The Kda value indicates that the F protein subunit forms a trimer through non-covalent formation. The T-numbered samples in the SDS-PAGE correspond to the T-numbered collection tubes of the molecular sieve.

[0086] Example 2: Isolation of RSV F (DS-Cav1) protein-specific memory B cells

[0087] With informed consent, 3-10 mL of blood was collected from individuals who had recovered from RSV infection and been discharged from the hospital, and PBMCs were isolated. The isolated PBMCs (10 mL) were then... 7 The cells were incubated with 400 nM DS-Cav1 protein (prepared in Example 1) on ice for half an hour. Then, the cells were washed twice with PBS and mixed with the following antibodies (all purchased from BD): anti-human CD3 / PE-Cy5, anti-human CD16 / PE-Cy5, anti-human CD235a / PE-Cy5, anti-human CD19 / APC-Cy7, anti-human CD27 / Pacific Blue, anti-human CD38 / APC, anti-human IgG / FITC, and anti-His / PE. After incubation on ice for half an hour, the cells were washed twice with PBS. Subsequently, PBMCs were sorted using FACSAria III, and cells with PE-Cy5-APC-APC-Cy7+Pacific Blue+FITC+PE+ (i.e., memory B cells) were collected directly into 96-well plates at 1 cell / well.

[0088] Example 3: Single B-cell PCR and cloning of human monoclonal antibody IgG1

[0089] Cells obtained in Example 2 were reverse transcribed using Superscript III reverse transcriptase (Invitrogen) at 55°C for 60 min. This reverse transcription product was used as a template for PCR amplification of the antibody variable region sequence (PCRa) using HotStar TapPlus enzyme (QIAgen). The reaction conditions were as follows: 95°C for 5 min; 95°C for 30 s, 55°C (heavy chain / κ chain) / 50°C (λ chain) for 30 s, 72°C for 90 s, 35 cycles, 72°C for 7 min. This was then used as a template for another round of PCR (PCRb) at the following conditions: 95°C for 5 min; 95°C for 30 s, 58°C (heavy chain) / 60°C (κ chain) / 64°C (λ chain) for 30 s, 72°C for 90 s, 35 cycles, 72°C for 7 min. The PCR products were separated by 1.2% agarose gel electrophoresis, and the 400-500 bp bands were excised and recovered for sequencing by a sequencing company. The sequencing results were analyzed on the IGBLAST website. The analysis results are as follows:

[0090] A total of four paired antibodies were obtained: RV7, RV8, RV10, and RV11. According to the sequencing results, the amino acid sequence of the heavy chain variable region of RV7 is SEQ ID NO: 2, and the amino acid sequence of the light chain variable region is SEQ ID NO: 3; the amino acid sequence of the heavy chain variable region of RV8 is SEQ ID NO: 4, and the amino acid sequence of the light chain variable region is SEQ ID NO: 5; the amino acid sequence of the heavy chain variable region of RV10 is SEQ ID NO: 6, and the amino acid sequence of the light chain variable region is SEQ ID NO: 7; the amino acid sequence of the heavy chain variable region of RV11 is SEQ ID NO: 8, and the amino acid sequence of the light chain variable region is SEQ ID NO: 9. The light chain sequencing results of the four antibodies were compared with germline genes to determine that RV7 uses CLκ; RV8 uses CLκ; RV10 uses CLλ; and RV11 uses CLλ.

[0091] To obtain human antibodies for further evaluation, we designed a method for constructing a complete anti-IgG1 antibody. The strategy is as follows:

[0092] Heavy chain: CMV promoter-Hind III-signal peptide (SP)-heavy chain variable region (VH)-heavy chain constant region (CH)-Not I;

[0093] Light chain κ: CMV promoter-Hind III-signal peptide (SP)-light chain variable region (VK)-light chain constant region (CLκ)-Not I;

[0094] Light chain λ: CMV promoter-Hind III-signal peptide (SP)-light chain variable region (VL)-light chain constant region (CLλ)-Not I;

[0095] The correct variable region sequences were analyzed and ligated to the corresponding heavy chain CH and light chain CLκ (or light chain CLλ) constant regions via bridging PCR, and cloned into the expression vector KT351861 to obtain a recombinant plasmid containing the light and heavy chain encoding genes of the specific antibody. The light and heavy chain variable regions were ligated into the vector containing the constant regions using Hind III and Not I restriction enzyme sites. The amino acid sequences of the heavy chain constant region CH are shown in SEQ ID NO: 10; the light chain constant region CLκ is shown in SEQ ID NO: 11; the light chain constant region CLλ is shown in SEQ ID NO: 12; and the signal peptide (SP) is shown in SEQ ID NO: 13.

[0096] Example 4: Expression and purification of monoclonal antibodies

[0097] 293T cells were cultured in DMEM containing 10% FBS. The recombinant expression vectors encoding the heavy and light chains of the antibodies, obtained in Example 3, were co-transfected into the 293T cells. Four to six hours after transfection, the cell culture medium was replaced with serum-free DMEM, and the cells were cultured for another 3 days. The supernatant was collected, and DMEM was added again, followed by culturing for another 4 days. The supernatant was collected again afterward.

[0098] The collected supernatant was centrifuged at 8000 rpm for 90 min, then mixed with an equal volume of buffer containing 20 mM sodium phosphate (pH 7.0), filtered through a 0.22 μm filter membrane, and loaded into a pre-packed column (5 mL, GE Healthcare) for protein A or G. Proteins bound to the pre-packed column were eluted with 100 mM glycine (pH 3.0). The elution fraction was concentrated and purified by molecular sieve chromatography. The purified target protein was then analyzed by SDS-PAGE (reducing and non-reducing). Under non-reducing conditions, the antibody showed a single band in SDS-PAGE; under reducing conditions, the Fc disulfide bonds of the antibody were opened, resulting in two bands, and the antibody purity exceeded 95%.

[0099] Example 5: Detection of antibody binding performance

[0100] (1) Construction and expression of F protein (FΔFP) after RSV fusion

[0101] The C-terminus of the fusion F protein (FΔFP) encoding the RSV A2 strain was augmented with a Thrombin restriction site, six histidine sequences, one GS [glycine-serine] linker sequence, one sequence encoding the Strep II tag, and one stop codon (amino acid sequence as shown in SEQ ID NO: 14), and inserted into the NdeI and XhoI restriction sites of the mammalian expression vector pCΔGGS. The ligation product was transformed into DH5α E. coli competent cells. Single colonies were then picked, inoculated into 4 mL of LB medium, and cultured for 6–8 hours; subsequently, they were transferred to 300 mL of LB medium and cultured for 12–16 hours. Cells were collected, and plasmids were extracted using an endotoxin-free plasmid extraction kit (TIΔNGEN) to obtain pCAGGS-RSV-FΔFP.

[0102] The extracted plasmid pCAGGS-RSV-FΔFP was transfected into 293T cells to express the F protein. Four to five days post-transfection, the 293T cell culture supernatant containing the target protein was centrifuged and filtered (0.22 μM) to remove cell debris. The supernatant was then bound to a HisTrap HP (GE Healthcare) nickel chelate column, followed by elution chromatography with different concentrations of imidazole. Eluted proteins were collected, and SDS-PAGE results were used to determine the samples containing the target protein.

[0103] The elution peaks containing the target protein were collected, concentrated, and then subjected to molecular sieve chromatography. The size and purity of the protein were determined based on the elution peak position and the results of SDS-PAGE.

[0104] (2) Preparation and purification of the full-length Fab fragment of monoclonal antibody

[0105] A. Sample preparation:

[0106] Concentrate the total antibody protein to above 10 mg / ml, and then change the concentration buffer (200-fold) to sample buffer (20 mM Na3PO4, 10 mM EDTA, pH 7.0). Concentrate the antibody after buffering to above 20 mg / ml, and then add a certain amount of digestion buffer (add cysteine·HCl to sample buffer to 20 mM, pH 7.0) to dilute to a final concentration ≥ 10 mg / ml.

[0107] B. Prepare enzymes:

[0108] Using a pipette tip with the tip cut off, pipette 0.5 mL of thoroughly mixed coupling enzyme beans (Thermo, Prod#20341) into a reaction vessel. Centrifuge at 1000 g / min for 2 min to remove the preservation solution. Wash the beans 3 times with 3 mL of digestion buffer and discard the eluent. Then add 0.5 mL of digestion buffer and gently invert to mix.

[0109] C. Enzyme digestion:

[0110] Add a plug to the reaction tube, add the concentrated antibody (about 10 mg), tighten the cap, and seal the gap with sealing film; fix the reaction tube to the rotary mixer and incubate overnight at 37°C;

[0111] D. Fab Recycling:

[0112] After overnight enzyme digestion, centrifuge at 1000g / min for 5min and retain the eluent; wash beans twice with 1mL Protein G binding buffer (20mM Na3PO4, pH7.0) and recover the eluent; mix the eluents from the above two steps and measure the concentration; concentrate the eluent and pass it through Protein G; concentrate the target protein eluent and change the buffer to 1×PBS buffer, and further purify it through a molecular sieve.

[0113] (3) Assessment of the binding ability of monoclonal antibodies to F protein

[0114] In this embodiment, surface plasmon resonance analysis was performed using a Biacore 3K (Biacore Inc.). The specific steps are as follows:

[0115] First, the pre-fusion F protein DS-Cav1 and the post-fusion F protein FΔFP were immobilized on the Fc2 and Fc4 channels (flow cells, Fc) of a CM5 chip via amino-coupled coupling. Then, the Fab proteins of purified RV7, RV8, RV10, and RV11 antibodies were bound using antibody capture. Palivizumab was used as a positive control. Additionally, the Fab proteins of RV7, RV8, RV10, RV11, and Palivizumab antibodies were serially diluted with 20 mM HEPES, 150 mM NaCl, and pH 7.4. The serially diluted Fab proteins were then sequentially loaded through each channel (starting from the lowest concentration). Kinetic curves of RV7, RV8, RV10, RV11, and Palivizumab antibody Fab binding to DS-Cav1 or FΔFP were recorded, and the kinetic constant KD was calculated using BIAevaluationsoftware 3K (Biacore, Inc.). The affinity results are shown in Table 1.

[0116] Table 1. Binding constants of antibody Fab fragments to pre-fusion F protein DS-Cav1 and post-fusion F protein FΔFP

[0117]

[0118] aNull indicates no binding.

[0119] Results analysis: RV7 binds neither to the pre-RSV fusion F protein nor to the post-RSV fusion F protein. RV8 binds to both the pre-RSV fusion F protein (K... D =25.6nM), and also binds to the fusion-bound F protein (K D =17.5nM). RV10 binds to both the pre-fusion F protein (K) and... D =10.1nM), and also binds to the fusion-bound F protein (K D =7.11nM); The RV11 antibody can only bind to the pre-fusion F protein (K) of RSV. D =7.18nM), does not bind to the fusion-bound F protein.

[0120] Example 6: Detection of antibody neutralizing activity

[0121] We used flow cytometry to detect the neutralizing activity of the antibody. The detailed steps are as follows: In short, we diluted the purified antibody to a series of concentrations, mixed it with the virus, incubated it for a period of time, and then infected susceptible cells prepared the day before. Two days later, the cells were fixed, permeabilized, stained with a primary antibody targeting the F protein, stained again with a labeled secondary antibody, and finally analyzed by flow cytometry to count the proportion of infected cells. The neutralizing activity of the antibody was then calculated.

[0122] Operating steps:

[0123] 1. Cell preparation

[0124] ①Sow Hep2 cells in 24-well plates 12-16 hours in advance and culture them in 10% DMEM medium. Perform antibody neutralization experiments the next day after the cells have grown to more than 70%.

[0125] ② Diluting the antibodies: Five antibodies, RV7, RV8, RV10, RV11 and Palivizumab, were purified and filtered under sterile conditions. The antibodies were added to 48-well plates and serially diluted 3-fold, with at least 350-400 μL per well using 2% FBS DMEM medium.

[0126] ③ Virus dilution: Thaw the virus from the -80% freezer, dilute it with 2% FBSDMEM medium according to the appropriate virus dilution factor, and then add it to a 48-well plate containing the antibody, 300 μL / well. (RSV_A2 or RSV-Long or RSV-B: dilute 450 μL to 40 mL, final titer: 1.2 × 10⁻⁶) 4 TCID50 / 100μL).

[0127] ④ Virus and antibody incubation:

[0128] Mix the diluted virus and antibody at a molar ratio of 1:1 and incubate in a 37°C CO2 incubator for 1 hour.

[0129] ⑤ Cell washing:

[0130] Ten minutes beforehand, remove the newly confluent Hep2 cells from the incubator, aspirate the culture medium with a pipette, wash the cells once with PBS, and add 500 μL of PBS to each well.

[0131] ⑥ Add virus antibody mixture: Aspirate the PBS from the cells, add 300 μL of the virus-cell supernatant mixture to each well of the cells, and incubate at 37°C for 1 hour. (One gradient has two wells, 11 gradients in total, and two virus control wells per plate)

[0132] ⑦ Replenishment of medium: After incubation, aspirate the supernatant and add 1 mL of DMEM medium containing penicillin-streptomycin mixture + 2% FBS to each well. Incubate the cells in an incubator for about 48 hours.

[0133] 2. Flow cytometry detection

[0134] ① Observe the infected cells and collect them after they develop appropriate cytopathic effects.

[0135] ② Digesting cells: Remove the cell culture medium, wash the cells once with PBS, add 120 μL of trypsin to each well, and incubate at 37°C for 2 min. After the cells detach, stop the reaction with 130 μL of 10% FBS + PBS.

[0136] ③ Transfer cells to 96-well round-bottom plates. Centrifuge at 500g, 4℃ for 10 min, and discard the supernatant.

[0137] ④ Wash once with 150 μL of 1% FBS+PBS per well, centrifuge as above, and discard the supernatant.

[0138] ⑤ Add 100 μL Fixation and Permeabilization Solution, fix the permeable cells for 30 min, and perform the procedure on ice at 4°C in the dark.

[0139] ⑥ Add 100 μL of 1× wash buffer and mix well. Centrifuge at 500 g, 4 °C for 10 min. Resuspend the cells in 100 μL of wash buffer. Spray the outside of the 96-well plate with alcohol and seal it. Transfer the plate from P3 to P2 for subsequent operations. For safety, let it stand overnight at 4 °C before proceeding. Alternatively, transfer the cells to a new round-bottom 96-well plate.

[0140] ⑦ Add primary antibody: Dilute the purified Palivizumab with 1×wash buffer to a concentration of 2 μg / mL. Centrifuge the cells, discard the supernatant, add 50 μL of antibody to each well, and incubate on ice for 30 min. Then, add 150 μL of 1×wash buffer, mix well, centrifuge, and discard the supernatant.

[0141] ⑧ Add secondary antibody: Dilute Anti-Human-IgG (FITC) with 1× wash buffer, dilute antibody 1:150, add 50 μL of antibody to each well, and incubate on ice for 30 min. Then, add 150 μL of 1× wash buffer, mix well, centrifuge and discard the supernatant. Repeat washing once. Finally, resuspend in 150 μL of PBS.

[0142] Final flow cytometry analysis: Flow cytometry analysis was performed using BD FACSAria II. FlowJo 7.6.1 was used for analysis.

[0143] result:

[0144] For RSV type A2 strain, the half-maximal inhibitory concentrations (IC50) of the antibodies were 539.5 ng / mL for RV8 and 42.3 ng / mL for RV11, both of which were superior to the marketed palivizumab at 751 ng / mL. The RV11 antibody, in particular, exhibited approximately 18 times stronger neutralizing activity than palivizumab. For the detection concentration range, RV7 and RV10 showed no neutralizing activity. Data are shown in Table 2.

[0145] Table 2 Neutralizing activity of antibodies against RSV type A A2 strain

[0146]

[0147] a Null indicates no neutralizing activity.

[0148] For RSV type A Long strain, the half-maximal inhibitory concentrations (IC50) of the antibodies were 842.9 ng / mL for RV8 and 56.3 ng / mL for RV11, both of which were superior to the marketed palivizumab (IC50 = 897.4 ng / mL), especially RV11, which showed approximately 16 times stronger neutralizing activity than palivizumab. RV7 showed no neutralizing activity within the detection concentration range. Data are shown in Table 3.

[0149] Table 3 Neutralizing activity of antibodies against RSV type A Long strain

[0150]

[0151] a Null indicates no neutralizing activity.

[0152] For clinical isolates of RSV type B, the half-maximal inhibitory concentrations (IC50) of the antibodies were: RV8 = 183.1 ng / mL and RV11 = 31.4 ng / mL, both of which were better than the marketed palivizumab (IC50 = 1413.0 ng / mL), especially the RV11 antibody, whose neutralizing activity was about 45 times stronger than palivizumab; the neutralizing activity of the RV8 antibody was also 7.7 times higher than that of palivizumab. Data are shown in Table 4.

[0153] Table 4. Neutralizing activity of antibodies against RSV type B clinical isolates.

[0154]

[0155] Some of the amino acid sequences mentioned in this disclosure are as follows:

[0156]

[0157]

[0158] SEQUENCE LISTING <110> Institute of Microbiology, Chinese Academy of Sciences <120> An antibody against respiratory syncytial virus and its application <130> P11143-PCT <150> CN202110653393.6 <151> 2021-06-11 <160> 32 <170> PatentIn version 3.5 <210> 1 <211> 564 <212> PRT <213> Artificial <220> <223> F protein before fusion <400> 1 Met Glu Leu Leu Ile Leu Lys Ala Asn Ala Ile Thr Thr Ile Leu Thr 1 5 10 15 Ala Val Thr Phe Cys Phe Ala Ser Gly Gln Asn Ile Thr Glu Glu Phe 20 25 30 Tyr Gln Ser Thr Cys Ser Ala Val Ser Lys Gly Tyr Leu Ser Ala Leu 35 40 45 Arg Thr Gly Trp Tyr Thr Ser Val Ile Thr Ile Glu Leu Ser Asn Ile 50 55 60 Lys Glu Asn Lys Cys Asn Gly Thr Asp Ala Lys Val Lys Leu Ile Lys 65 70 75 80 Gln Glu Leu Asp Lys Tyr Lys Asn Ala Val Thr Glu Leu Gln Leu Leu 85 90 95 Met Gln Ser Thr Pro Ala Thr Asn Asn Arg Ala Arg Arg Glu Leu Pro 100 105 110 Arg Phe Met Asn Tyr Thr Leu Asn Asn Thr Lys Lys Thr Asn Val Thr 115 120 125 Leu Ser Lys Lys Arg Lys Arg Arg Phe Leu Gly Phe Leu Leu Gly Val 130 135 140 Gly Ser Ala Ile Ala Ser Gly Val Ala Val Cys Lys Val Leu His Leu 145 150 155 160 Glu Gly Glu Val Asn Lys Ile Lys Ser Ala Leu Leu Ser Thr Asn Lys 165 170 175 Ala Val Val Ser Leu Ser Asn Gly Val Ser Val Leu Thr Phe Lys Val 180 185 190 Leu Asp Leu Lys Asn Tyr Ile Asp Lys Gln Leu Leu Pro Ile Leu Asn 195 200 205 Lys Gln Ser Cys Ser Ile Ser Asn Ile Glu Thr Val Ile Glu Phe Gln 210 215 220 Gln Lys Asn Asn Arg Leu Leu Glu Ile Thr Arg Glu Phe Ser Val Asn 225 230 235 240 Ala Gly Val Thr Thr Pro Val Ser Thr Tyr Met Leu Thr Asn Ser Glu 245 250 255 Leu Leu Ser Leu Ile Asn Asp Met Pro Ile Thr Asn Asp Gln Lys Lys 260 265 270 Leo Met Ser Asn Asn Val Gln Ile Val Arg Gln Gln Ser Tyr Ser Ile 275 280 285 Met Cys Ile Ile Lys Glu Glu Val Leu Ala Tyr Val Val Gln Leu Pro 290 295 300 Leu Tyr Gly Val Ile Asp Thr Pro Cys Trp Lys Leu His Thr Ser Pro 305 310 315 320 Leu Cys Thr Thr Asn Thr Lys Glu Gly Ser Asn Ile Cys Leu Thr Arg 325 330 335 Thr Asp Arg Gly Trp Tyr Cys Asp Asn Ala Gly Ser Val Ser Phe Phe 340 345 350 Pro Gln Ala Glu Thr Cys Lys Val Gln Ser Asn Arg Val Phe Cys Asp 355 360 365 Thr Met Asn Ser Leu Thr Leu Pro Ser Glu Val Asn Leu Cys Asn Val 370 375 380 Asp Ile Phe Asn Pro Lys Tyr Asp Cys Lys Ile Met Thr Ser Lys Thr 385 390 395 400 Asp Val Ser Ser Ser Val Ile Thr Ser Leu Gly Ala Ile Val Ser Cys 405 410 415 Tyr Gly Lys Thr Lys Cys Thr Ala Ser Asn Lys Asn Arg Gly Ile Ile 420 425 430 Lys Thr Phe Ser Asn Gly Cys Asp Tyr Val Ser Asn Lys Gly Val Asp 435 440 445 Thr Val Ser Val Gly Asn Thr Leu Tyr Tyr Val Asn Lys Gln Glu Gly 450 455 460 Lys Ser Leu Tyr Val Lys Gly Glu Pro Ile Ile Asn Phe Tyr Asp Pro 465 470 475 480 Leu Val Phe Pro Ser Asp Glu Phe Asp Ala Ser Ile Ser Gln Val Asn 485 490 495 Glu Lys Ile Asn Gln Ser Leu Ala Phe Ile Arg Lys Ser Asp Glu Leu 500 505 510 Leu Gly Ser Gly Tyr Ile Pro Glu Ala Pro Arg Asp Gly Gln Ala Tyr 515 520 525 Val Arg Lys Asp Gly Glu Trp Val Leu Leu Ser Thr Phe Leu Leu Val 530 535 540 Pro Arg Gly Ser His His His His His His Gly Ser Trp Ser His Pro 545 550 555 560 Gln Phe Gly Lys <210> 2 <211> 118 <212> PRT <213> Artificial <220> <223> RV7 heavy chain variable region <400> 2 Gln Val Gln Leu Gln Glu Ser Gly Pro Gly Leu Val Lys Pro Ser Glu 1 5 10 15 Thr Leu Ser Leu Thr Cys Thr Val Ser Gly Gly Ser Ile Ser Ser Tyr 20 25 30 Tyr Leu Ser Trp Ile Arg Gln Pro Pro Gly Lys Gly Leu Glu Trp Ile 35 40 45 Gly Tyr Ile Tyr His Thr Gly Ser Thr Asn Tyr Asn Pro Ser Leu Lys 50 55 60 Ser Arg Val Thr Ile Ser Val His Ser Ser Lys Asn Gln Phe Ser Leu 65 70 75 80 Lys Leu Thr Ser Val Thr Ala Ala Asp Thr Ala Val Tyr Tyr Cys Ala 85 90 95 Arg His Met Arg Ile Val Thr Thr Ile Asp Tyr Trp Gly Gln Gly Thr 100 105 110 Leu Val Thr Val Ser Ser 115 <210> 3 <211> 107 <212> PRT <213> Artificial <220> <223> RV7 light chain variable region <400> 3 Asp Ile Val Met Thr Gln Ser Pro Ser Ser Leu Ser Ala Ser Val Gly 1 5 10 15 Asp Arg Val Thr Leu Thr Cys Arg Ala Ser Gln Gly Ile Ser Ser Tyr 20 25 30 Leu Ala Trp Tyr Gln Gln Lys Pro Gly Lys Val Pro Lys Leu Leu Ile 35 40 45 Tyr Ala Ala Ser Thr Leu Gln Ser Gly Val Pro Ser Arg Phe Ser Gly 50 55 60 Ser Gly Ser Gly Thr Asp Phe Thr Leu Thr Ile Ser Ser Leu Gln Pro 65 70 75 80 Glu Asp Val Ala Thr Tyr Tyr Cys Gln Lys Tyr Asn Ser Ala Pro Trp 85 90 95 Thr Phe Gly Gln Gly Thr Lys Val Glu Ile Lys 100 105 <210> 4 <211> 121 <212> PRT <213> Artificial <220> <223> RV8 heavy chain variable region <400> 4 Gln Val Gln Leu Val Gln Ser Gly Gly Gly Val Val Gln Pro Gly Arg 1 5 10 15 Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Phe Thr Phe Ser Ser Tyr 20 25 30 Ala Met His Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu Trp Met 35 40 45 Ala Val Ile Ser Tyr Asp Gly Ser Asn Thr Tyr Tyr Ala Asp Ser Val 50 55 60 Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr Leu Tyr 65 70 75 80 Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Met Phe Tyr Cys 85 90 95 Ala Arg Asp Tyr Cys Ser Arg Gly Thr Cys Tyr His Asp Tyr Trp Gly 100 105 110 Gln Gly Thr Leu Val Thr Val Ser Ser 115 120 <210> 5 <211> 107 <212> PRT <213> Artificial <220> <223> Variable region of RV8 light chain <400> 5 Asp Ile Val Leu Thr Gln Ser Pro Ser Ser Leu Ser Ala Ser Val Gly 1 5 10 15 Asp Arg Val Thr Ile Thr Cys Arg Ala Ser Gln Asp Ile Arg Asn Asp 20 25 30 Leu Ser Trp Tyr Gln Gln Lys Pro Gly Lys Ala Pro Lys Leu Leu Ile 35 40 45 Tyr Ala Ala Ser Ser Leu Gln Ser Gly Val Pro Ser Arg Phe Ser Gly 50 55 60<00005Ser Gly Ser Gly Thr Asp Phe Thr Leu Thr Ile Ser Ser Leu Gln Pro 65 70 75 80 Glu Asp Phe Ala Thr Tyr Ser Cys Leu Gln Asp Tyr Asn Tyr Pro Gln 85 90 95 Thr Phe Gly Gln Gly Thr Lys Val Glu Ile Lys 100 105 <210> 6 <211> 118 <212> PRT <213> Artificial <220> <223> Variable region of the heavy chain of RV10 <400> 6 Gln Val Gln Leu Val Gln Ser Gly Ala Glu Val Lys Lys Pro Gly Ala 1 5 10 15 Ser Val Lys Val Ser Cys Lys Ala Ser Gly Tyr Thr Phe Thr Thr Tyr 20 25 30 Asp Phe His Trp Val Arg Gln Ala Pro Gly Gln Gly Leu Glu Trp Ile 35 40 45 Gly Trp Leu Asn Pro Asp Asn Gly Asn Thr Lys His Ser Gln Lys Phe 50 55 60 Gln Gly Arg Val Thr Phe Thr Arg Asp Thr Ser Ala Ser Thr Ala Phe 65 70 75 80 Met Glu Leu Ser Ser Leu Arg Ser Glu Asp Thr Ala Val Tyr Tyr Cys 85 90 95 Thr Arg Ala Pro Trp Trp Trp Tyr Phe Asp Tyr Trp Gly Gln Gly Thr 100 105 110 Leu Val Thr Val Ser Ser 115 <210> 7 <211> 115 <212> PRT <213> Artificial <220> <223> Variable region of the light chain of RV10 <400> 7 Asn Phe Met Leu Thr Gln Pro His Ser Val Ser Glu Ser Pro Gly Lys 1 5 10 15 Thr Val Thr Ile Ser Cys Thr Arg Ser Ser Gly Ser Ile Ala Ser Asn 20 25 30 Tyr Val Gln Trp Cys Gln Gln Arg Pro Gly Ser Ser Pro Thr Thr Val 35 40 45 Ile Tyr Glu Asp Asn Gln Arg Pro Ser Gly Val Pro Asp Arg Phe Ser 50 55 60 Gly Ser Ile Asp Ser Ser Ser Asn Ser Ala Ser Leu Thr Ile Ser Gly 65 70 75 80 Leu Arg Thr Glu Asp Glu Ala Asp Tyr Tyr Cys Gln Ser Tyr Asp Thr 85 90 95 Ser Asn Ala Val Phe Gly Gly Gly Thr Lys Leu Thr Val Leu Gly Gln 100 105 110 Pro Lys Ala 115 <210> 8 <211> 133 <212> PRT <213> Artificial <220> <223> RV11 heavy chain variable region <400> 8 Gln Val Gln Leu Val Gln Ser Gly Gly Gly Val Val Gln Pro Gly Arg 1 5 10 15 Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Phe Ser Phe Thr Asn Tyr 20 25 30 Gly Met His Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu Trp Val 35 40 45 Ala Val Ile Ser Tyr Asp Asp Gly Ser Asp Lys Tyr Tyr Ala Asp Ser 50 55 60 Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr Leu 65 70 75 80 Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr Tyr 85 90 95 Cys Val Arg Asp Pro Thr Gly Asp Tyr Gly Asp Phe Pro Glu Gln Asp 100 105 110 Gly Tyr Tyr Tyr Tyr Tyr Gly Met Asp Val Trp Gly Gln Gly Thr Thr 115 120 125 Val Thr Val Ser Ser 130 <210> 9 <211> 115 <212> PRT <213> Artificial <220> <223> RV11 flexible chain <400> 9 Gln Ala Val Leu Thr Gln Pro Pro Ser Ala Ser Gly Thr Pro Gly Gln 1 5 10 15 Arg Val Thr Ile Ser Cys Ser Gly Ser Ser Leu Asn Ile Gly Ser Asn 20 25 30 Tyr Val Tyr Trp Tyr Gln Gln Leu Pro Gly Thr Ala Pro Lys Phe Leu 35 40 45 Ile Tyr Lys Asn Asn Gln Arg Pro Ser Gly Val Pro Asp Arg Phe Ser 50 55 60 Gly Ser Lys Ser Gly Thr Ser Ala Ser Leu Ala Ile Ser Gly Leu Arg 65 70 75 80 Ser Glu Asp Glu Ala Asp Tyr Tyr Cys Ala Ala Trp Asp Asp Ser Leu 85 90 95 Ser Gly Val Val Phe Gly Gly Gly Thr Lys Leu Thr Val Leu Gly Gln 100 105 110 Pro Lys Ala 115 <210> 10 <211> 330 <212> PRT <213> Artificial <220> <223> Heavy chain constant region <400> 10 Ala Ser Thr Lys Gly Pro Ser Val Phe Pro Leu Ala Pro Ser Ser Lys 1 5 10 15 Ser Thr Ser Gly Gly Thr Ala Ala Leu Gly Cys Leu Val Lys Asp Tyr 20 25 30 Phe Pro Glu Pro Val Thr Val Ser Trp Asn Ser Gly Ala Leu Thr Ser 35 40 45 Gly Val His Thr Phe Pro Ala Val Leu Gln Ser Ser Gly Leu Tyr Ser 50 55 60 Leu Ser Ser Val Val Thr Val Pro Ser Ser Ser Leu Gly Thr Gln Thr 65 70 75 80 Tyr Ile Cys Asn Val Asn His Lys Pro Ser Asn Thr Lys Val Asp Lys 85 90 95 Arg Val Glu Pro Lys Ser Cys Asp Lys Thr His Thr Cys Pro Pro Cys 100 105 110 Pro Ala Pro Glu Leu Leu Gly Gly Pro Ser Val Phe Leu Phe Pro Pro 115 120 125 Lys Pro Lys Asp Thr Leu Met Ile Ser Arg Thr Pro Glu Val Thr Cys 13​Val Val Val Asp Val Ser His Glu Asp Pro Glu Val Lys Phe Asn Trp 145 150 155 160 Tyr Val Asp Gly Val Glu Val His Asn Ala Lys Thr Lys Pro Arg Glu 165 170 175 Glu Gln Tyr Asn Ser Thr Tyr Arg Val Val Ser Val Leu Thr Val Leu 180 185 190 His Gln Asp Trp Leu Asn Gly Lys Glu Tyr Lys Cys Lys Val Ser Asn 195 200 205 Lys Ala Leu Pro Ala Pro Ile Glu Lys Thr Ile Ser Lys Ala Lys Gly 210 215 220 Gln Pro Arg Glu Pro Gln Val Tyr Thr Leu Pro Pro Ser Arg Asp Glu 225 230 235 240 Leu Thr Lys Asn Gln Val Ser Leu Thr Cys Leu Val Lys Gly Phe Tyr 245 250 255 Pro Ser Asp Ile Ala Val Glu Trp Glu Ser Asn Gly Gln Pro Glu Asn 260 265 270 Asn Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser Asp Gly Ser Phe Phe 275 280 285 Leu Tyr Ser Lys Leu Thr Val Asp Lys Ser Arg Trp Gln Gln Gly Asn 290 295 300 Val Phe Ser Cys Ser Val Met His Glu Ala Leu His Asn His Tyr Thr 305 310 315 320 Gln Lys Ser Leu Ser Leu Ser Pro Gly Lys 325 330 <210> 11 <211> 108 <212> PRT <213> Artificial <220> <223> Light chain constant region CLκ <400> 11 Arg Thr Val Ala Ala Pro Ser Val Phe Ile Phe Pro Pro Ser Asp Glu 1 5 10 15 Gln Leu Lys Ser Gly Thr Ala Ser Val Val Cys Leu Leu Asn Asn Phe 20 25 30 Tyr Pro Arg Glu Ala Lys Val Gln Trp Lys Val Asp Asn Ala Leu Gln 35 40 45 Ser Gly Asn Ser Gln Glu Ser Val Thr Glu Gln Asp Ser Lys Asp Ser 50 55 60 Thr Tyr Ser Leu Ser Ser Thr Leu Thr Leu Ser Lys Ala Asp Tyr Glu 65 70 75 80 Lys His Lys Val Tyr Ala Cys Glu Val Thr His Gln Gly Leu Ser Ser 85 90 95 Pro Val Thr Lys Ser Phe Asn Arg Gly Glu Cys Ser 100 105 <210> 12 <211> 101 <212> PRT <213> Artificial <220> <223> Constant region of light chain CLλ <400> 12 Ala Pro Ser Val Thr Leu Phe Pro Pro Ser Ser Glu Glu Leu Gln Ala 1 5 10 15 Asn Lys Ala Thr Leu Val Cys Leu Ile Ser Asp Phe Tyr Pro Gly Ala 20 25 30 Val Thr Val Ala Trp Lys Ala Asp Ser Ser Pro Val Lys Ala Gly Val 35 40 45 Glu Thr Thr Thr Pro Ser Lys Gln Ser Asn Asn Lys Tyr Ala Ala Ser 50 55 60 Ser Tyr Leu Ser Leu Thr Pro Glu Gln Trp Lys Ser His Arg Ser Tyr 65 70 75 80 Ser Cys Gln Val Thr His Glu Gly Ser Thr Val Glu Lys Thr Val Ala 85 90 95 Pro Thr Glu Cys Ser 100 <210> 13 <211> 20 <212> PRT <213> Artificial <220> <223> Signal peptide <400> 13 Glu Thr Asp Thr Leu Leu Leu Trp Val Leu Leu Leu Trp Val Pro Gly 1 5 10 15 Ser Thr Gly Asp 20 <210> 14 <211> 527 <212> PRT <213> Artificial <220> <223> fusion <400> 14 Met Glu Leu Leu Ile Leu Lys Ala Asn Ala Ile Thr Thr Ile Leu Thr 1 5 10 15 Ala Val Thr Phe Cys Phe Ala Ser Gly Gln Asn Ile Thr Glu Glu Phe 20 25 30 Tyr Gln Ser Thr Cys Ser Ala Val Ser Lys Gly Tyr Leu Ser Ala Leu 35 40 45 Arg Thr Gly Trp Tyr Thr Ser Val Ile Thr Ile Glu Leu Ser Asn Ile 50 55 60 Lys Glu Asn Lys Cys Asn Gly Thr Asp Ala Lys Val Lys Leu Ile Lys 65 70 75 80 Gln Glu Leu Asp Lys Tyr Lys Asn Ala Val Thr Glu Leu Gln Leu Leu 85 90 95 Met Gln Ser Thr Pro Ala Thr Asn Asn Arg Ala Arg Arg Glu Leu Pro 100 105 110 Arg Phe Met Asn Tyr Thr Leu Asn Asn Ala Lys Lys Thr Asn Val Thr 115 120 125 Leu Ser Lys Lys Arg Lys Arg Arg Ala Ile Ala Ser Gly Val Ala Val 130 135 140 Ser Lys Val Leu His Leu Glu Gly Glu Val Asn Lys Ile Lys Ser Ala 145 150 155 160 Leu Leu Ser Thr Asn Lys Ala Val Val Ser Leu Ser Asn Gly Val Ser 165 170 175 Val Leu Thr Ser Lys Val Leu Asp Leu Lys Asn Tyr Ile Asp Lys Gln 180 185 190 Leu Leu Pro Ile Val Asn Lys Gln Ser Cys Ser Ile Ser Asn Ile Glu 195 200 205 Thr Val Ile Glu Phe Gln Gln Lys Asn Asn Arg Leu Leu Glu Ile Thr 210 215 220 Arg Glu Phe Ser Val Asn Ala Gly Val Thr Thr Pro Val Ser Thr Tyr 225 230 235 240 Met Leu Thr Asn Ser Glu Leu Leu Ser Leu Ile Asn Asp Met Pro Ile 245 250 255 Thr Asn Asp Gln Lys Lys Leu Met Ser Asn Asn Val Gln Ile Val Arg 260 265 270 Gln Gln Ser Tyr Ser Ile Met Ser Ile Ile Lys Glu Glu Val Leu Ala 275 280 285 Tyr Val Val Gln Leu Pro Leu Tyr Gly Val Ile Asp Thr Pro Cys Trp 290 295 300 Lys Leu His Thr Ser Pro Leu Cys Thr Thr Asn Thr Lys Glu Gly Ser 305 310 315 320 Asn Ile Cys Leu Thr Arg Thr Asp Arg Gly Trp Tyr Cys Asp Asn Ala 325 330 335 Gly Ser Val Ser Phe Phe Pro Gln Ala Glu Thr Cys Lys Val Gln Ser 340 345 350 Asn Arg Val Phe Cys Asp Thr Met Asn Ser Leu Thr Leu Pro Ser Glu 355 360 365 Val Asn Leu Cys Asn Val Asp Ile Phe Asn Pro Lys Tyr Asp Cys Lys 370 375 380 Ile Met Thr Ser Lys Thr Asp Val Ser Ser Ser Val Ile Thr Ser Leu 385 390 395 400 Gly Ala Ile Val Ser Cys Tyr Gly Lys Thr Lys Cys Thr Ala Ser Asn 405 410 415 Lys Asn Arg Gly Ile Ile Lys Thr Phe Ser Asn Gly Cys Asp Tyr Val 420 425 430 Ser Asn Lys Gly Val Asp Thr Val Ser Val Gly Asn Thr Leu Tyr Tyr 435 440 445 Val Asn Lys Gln Glu Gly Lys Ser Leu Tyr Val Lys Gly Glu Pro Ile 450 455 460 Ile Asn Phe Tyr Asp Pro Leu Val Phe Pro Ser Asp Glu Phe Asp Ala 465 470 475 480 Ser Ile Ser Gln Val Asn Glu Lys Ile Asn Gln Ser Leu Ala Phe Ile 485 490 495 Arg Lys Ser Asp Glu Leu Leu Leu Val Pro Arg Gly Ser His His His 500 505 510 His His His His His Gly Ser Trp Ser His Pro Gln Phe Gly Lys 515 520 525 <210> 15 <211> 6 <212> PRT <213> Artificial <220> <223> LCDR1 <400> 15 Gln Asp Ile Arg Asn Asp 1 5 <210> 16 <211> 3 <212> PRT <213> Artificial <220> <223> LCDR2 <400> 16 Ala Ala Ser 1 <210> 17 <211> 11 <212> PRT <213> Artificial <220> <223> LCDR3 <400> 17 Leu Gln Asp Tyr Asn Tyr Pro Gln Thr Phe Gly 1 5 10 <210> 18 <211> 8 <212> PRT <213> Artificial <220> <223> HCDR1 <400> 18 Gly Phe Thr Phe Ser Ser Tyr Ala 1 5 <210> 19 <211> 8 <212> PRT <213> Artificial <220> <223> HCDR2 <400> 19 Ile Ser Tyr Asp Gly Ser Asn Thr 1 5 <210> 20 <211> 14 <212> PRT <213> Artificial <220> <223> HCDR3 <400> 20 Ala Arg Asp Tyr Cys Ser Arg Gly Thr Cys Tyr His Asp Tyr 1 5 10 <210> 21 <211> 8 <212> PRT <213> Artificial <220> <223> LCDR1 <400> 21 Ser Gly Ser Ile Ala Ser Asn Tyr 1 5 <210> 22 <211> 3 <212> PRT <213> Artificial <220> <223> LCDR2 <400> 22 Glu Asp Asn 1 <210> 23 <211> 11 <212> PRT <213> Artificial <220> <223> LCDR3 <400> 23 Gln Ser Tyr Asp Thr Ser Asn Ala Val Phe Gly 1 5 10 <210> 24 <211> 8 <212> PRT <213> Artificial <220> <223> HCDR1 <400> 24 Gly Tyr Thr Phe Thr Thr Tyr Asp 1 5 <210> 25 <211> 8 <212> PRT <213> Artificial <220> <223> HCDR2 <400> 25 Leu Asn Pro Asp Asn Gly Asn Thr 1 5 <210> 26 <211> 11 <212> PRT <213> Artificial <220> <223> HCDR3 <400> 26 Thr Arg Ala Pro Trp Trp Trp Tyr Phe Asp Tyr 1 5 10 <210> 27 <211> 8 <212> PRT <213> Artificial <220> <223> LCDR1 <400> 27 Ser Leu Asn Ile Gly Ser Asn Tyr 1 5 <210> 28 <211> 3 <212> PRT <213> Artificial <220> <223> LCDR2 <400> 28 Lys Asn Asn 1 <210> 29 <211> 13 <212> PRT <213> Artificial <220> <223> LCDR3 <400> 29 Ala Ala Trp Asp Asp Ser Leu Ser Gly Val Val Phe Gly 1 5 10 <210> 30 <211> 8 <212> PRT <213> Artificial <220> <223> HCDR1 <400> 30 Gly Phe Ser Phe Thr Asn Tyr Gly 1 5 <210> 31 <211> 9 <212> PRT <213> Artificial <220> <223> HCDR2 <400> 31 Ile Ser Tyr Asp Asp Gly Ser Asp Lys 1 5 <210> 32 <211> 8 <212> PRT <213> Artificial <220> <223> HCDR3 <400> 32 Val Arg Asp Pro Thr Gly Asp Tyr 1 5

Claims

1. An antibody or antigen-binding fragment thereof that binds to the respiratory syncytial virus (RSV) F protein, comprising a heavy chain variable region and a light chain variable region, wherein the HCDR1, HCDR2, and HCDR3 of the heavy chain variable region and the LCDR1, LCDR2, and LCDR3 of the light chain variable region are selected from one of the following combinations: (1) The amino acid sequence of LCDR1 is: QDIRND; The amino acid sequence of LCDR2 is: AAS; The amino acid sequence of LCDR3 is: LQDYNYPQTFG; The amino acid sequence of HCDR1 is: GFTFSSYA; The amino acid sequence of HCDR2 is: ISYDGSNT; The amino acid sequence of HCDR3 is: ARDYCSRGTCYHDY; (2) The amino acid sequence of LCDR1 is: SGSIASNY; The amino acid sequence of LCDR2 is: EDN; The amino acid sequence of LCDR3 is: QSYDTSNAVFG; The amino acid sequence of HCDR1 is: GYTFTTYD; The amino acid sequence of HCDR2 is: LNPDNGNT; The amino acid sequence of HCDR3 is: TRAPWWWYFDY; and (3) The amino acid sequence of LCDR1 is: SLNIGSNY; The amino acid sequence of LCDR2 is: KNN; The amino acid sequence of LCDR3 is: AAWDDSLSGVVFG; The amino acid sequence of HCDR1 is: GFSFTNYG; The amino acid sequence of HCDR2 is: ISYDDGSDK; The amino acid sequence of HCDR3 is: VRDPTGDY.

2. The antibody or antigen-binding fragment thereof as claimed in claim 1, wherein the heavy chain variable region comprises an amino acid sequence having at least 90% sequence identity with the sequence shown in SEQ ID NO: 4, 6 or 8.

3. The antibody or its antigen-binding fragment as described in claim 1 or 2, wherein... The heavy chain variable region comprises an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 4, and the light chain variable region comprises an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 5; or The heavy chain variable region comprises an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 6, and the light chain variable region comprises an amino acid sequence that is at least 90% sequence identical to SEQ ID NO: 7; or The heavy chain variable region includes an amino acid sequence that is at least 90% identical to SEQ ID NO: 8, and the light chain variable region includes an amino acid sequence that is at least 90% identical to SEQ ID NO:

9.

4. The antibody or antigen-binding fragment thereof as claimed in claim 1 or 2, wherein the heavy chain constant region of the antibody comprises an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 10; and the light chain constant region of the antibody comprises an amino acid sequence having at least 90% sequence identity with SEQ ID NO: 11 or 12.

5. The antibody or antigen-binding fragment thereof as described in claim 1 or 2, wherein the antibody is a human antibody.

6. The antibody or antigen-binding fragment thereof as described in claim 1 or 2, wherein the F protein is in its pre-fusion conformation.

7. The antibody or antigen-binding fragment thereof as described in claim 1 or 2, wherein the respiratory syncytial virus is type A or type B respiratory syncytial virus.

8. A nucleic acid molecule encoding an antibody or an antigen-binding fragment thereof as described in any one of claims 1 to 7.

9. An expression vector comprising the nucleic acid molecule as described in claim 8.

10. A host cell comprising or expressing an antibody or an antigen-binding fragment thereof as described in any one of claims 1 to 7; or comprising a nucleic acid molecule as described in claim 8; or comprising an expression vector as described in claim 9.

11. A pharmaceutical composition comprising an antibody or an antigen-binding fragment thereof as claimed in any one of claims 1 to 7, and one or more pharmaceutically acceptable carriers or excipients.

12. The pharmaceutical composition of claim 11, wherein the pharmaceutical composition comprises a diluent.

13. The pharmaceutical composition of claim 11, wherein the pharmaceutical composition comprises a buffer.

14. A method for detecting the presence or content of respiratory syncytial virus in a sample for non-diagnostic purposes, comprising contacting the sample with an antibody or antigen-binding fragment thereof as described in any one of claims 1-7, and detecting whether an antigen-antibody complex is formed or the amount of the antigen-antibody complex formed.

15. A respiratory syncytial virus (RSV) detection kit, comprising an antibody or an antigen-binding fragment thereof as described in any one of claims 1 to 7.

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