CN113603771A - Novel crown antibody or antigen binding fragment thereof and application thereof - Google Patents

Novel crown antibody or antigen binding fragment thereof and application thereof Download PDF

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CN113603771A
CN113603771A CN202111063235.1A CN202111063235A CN113603771A CN 113603771 A CN113603771 A CN 113603771A CN 202111063235 A CN202111063235 A CN 202111063235A CN 113603771 A CN113603771 A CN 113603771A
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antibody
protein
fragment
antigen
sars
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刘春艳
张翼
易嘉乐
罗沛
钟振宇
李瑞净
刘旭霞
秦汤
吴仁贞
阳馨滢
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Fapon Biotech Inc
Guangdong Fapon Biotech Co Ltd
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    • G01—MEASURING; TESTING
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    • G01N2333/08—RNA viruses
    • G01N2333/165—Coronaviridae, e.g. avian infectious bronchitis virus
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2469/00—Immunoassays for the detection of microorganisms
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Abstract

The invention relates to a novel crown antibody or an antigen binding fragment thereof and application thereof. The antibody provided by the invention has high sensitivity, good specificity and no cross reaction, and plays an important role in diagnosing novel coronavirus.

Description

Novel crown antibody or antigen binding fragment thereof and application thereof
Technical Field
The invention belongs to the field of protein detection. More particularly, it relates to a novel crown antibody or an antigen-binding fragment thereof and uses thereof.
Background
Coronavirus is a enveloped single-stranded positive-stranded RNA virus. Coronaviruses are divided into four genera according to their genetic evolution, serology and host-specific differences: alpha-coronavirus genus, beta-coronavirus genus, gamma-coronavirus genus, and delta-coronavirus genus. Viruses of the genus beta coronaviruses can be further divided into A, B, C, D four groups. Alpha and beta coronaviruses mainly infect mammals including humans, domestic animals, pets, and gamma and delta coronaviruses mainly infect birds and mammals. The new coronavirus belongs to the genus beta-coronavirus, 2019-nCoV is adjacent to SARS and SARS-like virus group in terms of the position of the evolutionary tree, and the evolutionary common outer group is HKU9-1 coronavirus parasitizing to fruit bat. 2019-nCoV has envelope, and the granule is round or elliptical, usually polymorphic, and has diameter of 50-200 nm.
SARS-CoV-2 belongs to the family of coronaviridae, an unfragmented single-stranded positive-stranded RNA virus. It encodes two large overlapping open reading frames (ORF1a and ORF1b), 4 structural proteins (S, E, M and N protein), and 9 accessory proteins. Wherein the N protein is the core component of the virion, which binds to the viral genomic RNA and packages the RNA into a Ribonucleoprotein (RNP) complex. In addition to assembly, the N protein plays an important role in viral mRNA transcription and replication, and is involved in immune regulation. Research reports that the N protein can be combined with double-stranded RNA to have RNAi inhibitory activity, can resist host RNAi mediated antiviral reaction, and can induce humoral and cellular immune response after infection, so that the N protein becomes a key target for early rapid diagnosis and vaccine development.
The SARS-CoV-2N protein has a total length of 419 amino acids, and the size is 43-50 kDa. The N protein has three relatively conserved structural domains, one of which can be intertwined with the viral genome RNA to form the viral nucleocapsid, plays an important role in the synthesis process of the viral RNA and is related to the replication of the viral genome and the regulation of cell signaling pathways. The N protein is a phosphorylated protein, and phosphorylation can regulate the conformation of the N protein, enhance the conformation of the N protein and enhance the affinity of the N protein and the virus RNA. During the nucleocapsid packaging process, the N protein can interact with the M protein to facilitate nucleocapsid packaging into virions. An organism in early infection can generate high-level antibodies for resisting N protein, and a method for quickly detecting 2019-nCoV serum antibodies can be established by utilizing the N protein. Therefore, the N protein is often used as a diagnostic detection tool for coronavirus and is a core raw material of an immunological rapid diagnostic reagent.
In conclusion, the 2019-nCoV N protein detection has an important effect on the diagnosis of novel coronaviruses, and the development of the monoclonal antibody for detecting the 2019-nCoV N protein has important significance.
Disclosure of Invention
The invention aims to provide a novel crown antibody or an antigen binding fragment thereof and application thereof.
In some embodiments, the invention may include one or more of the following:
an antibody or antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment thereof binds to an amino acid fragment from position 44 to 180 of the SARS-CoV-2 nucleocapsid protein.
And in some embodiments, the antibody or antigen binding fragment thereof further does not bind to an amino acid fragment at positions 44-84, an amino acid fragment at positions 65-103, an amino acid fragment at positions 96-136, and an amino acid fragment at position 130-180 of the SARS-CoV-2 nucleocapsid protein.
It is another object of the present invention to provide an antibody pair comprising an antibody or antigen-binding fragment thereof as described above.
The invention also provides fusion proteins, nucleic acid molecules, expression vector constructs and host cells comprising the amino acid fragments.
The invention also provides a kit comprising the antibody, the antibody pair, the fusion protein, the nucleic acid molecule, the expression vector construct or the host cell described above.
The invention also provides the antibody or the antigen binding fragment thereof, or the application of the antibody in preparation of a kit.
The invention also provides a method for preparing the antibody.
The antibody provided by the invention has high sensitivity, good specificity and no cross reaction, and plays an important role in diagnosing novel coronavirus.
Detailed Description
The invention relates to an antibody or an antigen binding fragment thereof, wherein the antibody or the antigen binding fragment thereof binds to the 44 th to 180 th amino acid fragments of SARS-CoV-2 nucleocapsid protein, and the antibody or the antigen binding fragment thereof can further not bind to the 44 th to 84 th amino acid fragments, the 65 th to 103 th amino acid fragments, the 96 th to 136 th amino acid fragments and the 130 th and 180 th amino acid fragments of SARS-CoV-2 nucleocapsid protein.
In the present invention, the term "antibody" is used in the broadest sense and may include full-length monoclonal antibodies, bispecific or multispecific antibodies, and chimeric antibodies, so long as they exhibit the desired biological activity. The term "antigen-binding fragment" is a substance that comprises a portion or all of an antibody CDR that lacks at least some of the amino acids present in the full-length chain but is still capable of specifically binding to an antigen. Such fragments are biologically active in that they bind to an antigen and can compete with other antigen binding molecules, including whole antibodies, for binding to a given epitope. Such fragments are selected from Fab (consisting of a complete light chain and Fd), Fv (consisting of VH and VL), scFv (single chain antibody, connected by a linker peptide between VH and VL) or single domain antibody (consisting of VH only). Such fragments may be produced by recombinant nucleic acid techniques, or may be produced by enzymatic or chemical cleavage of antigen binding molecules, including intact antibodies.
In some embodiments, an antibody that binds to an amino acid fragment corresponding to a SARS-CoV-2 nucleocapsid protein refers to an antibody that is capable of binding to the amino acid fragment, but the amino acid fragment is not necessarily the smallest binding fragment.
In some embodiments, the invention also provides an antibody pair, wherein said antibody pair comprises at least two of said antibodies; in some embodiments, the antibody pair comprises antibody 1 described above and antibody 2 that binds to an amino acid fragment 65-103 of the SARS-CoV-2 nucleocapsid protein.
In some embodiments, the invention also provides a fusion protein, wherein the fusion protein comprises a fragment of amino acids 44-180 of the SARS-CoV-2 nucleocapsid protein.
In some embodiments, the invention also provides a nucleic acid molecule, wherein the nucleic acid molecule encodes the fusion protein.
Nucleic acids are typically RNA or DNA, and nucleic acid molecules can be single-stranded or double-stranded. A nucleic acid is "operably linked" when it is placed into a functional relationship with another nucleic acid sequence. For example, a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the coding sequence. DNA nucleic acid is used when it is ligated to a vector.
In some embodiments, the invention also provides an expression vector construct, wherein the expression vector construct comprises the nucleic acid molecule.
In some embodiments, the invention also provides an isolated host cell, wherein the host cell comprises the expression vector construct.
In some embodiments, the invention also provides a kit, wherein the kit comprises the antibody, the antibody pair, the fusion protein, the nucleic acid molecule, the expression vector construct, or the host cell.
In some embodiments, the effect of the antibodies of the invention, such as binding activity and/or cross-reactivity, can be tested using any suitable in vitro assay, cell-based assay, in vivo assay, animal model, and the like. In some embodiments, the assay may include, for example, ELISA, FACS binding assay, Biacore, competitive binding assay, and the like. In some embodiments, the reactivity of the antibodies of the invention to the binding of an antigen (antigenic peptide) is characterized, for example, in an ELISA, and a reactivity ≧ 0.5, for example, at 405nm as read by an ELISA method with peroxidase labeling, is determined to be better, and can be used in immunoassays.
In some embodiments, wherein the antibody is optionally labeled with a detectable label. In some embodiments, detectable labels such as colloidal gold, radiolabels, luminescent substances, coloured substances, enzymes, e.g. fluorescent labels, chromophore labels, electron dense labels, e.g. radioisotopes, fluorophores, rhodamine and its derivatives, luciferase, fluorescein, horseradish peroxidase, alkaline phosphatase, beta-galactosidase, glucoamylase, lysozyme, carbohydrate oxidase, glucose oxidase, galactose oxidase, and glucose-6-phosphate dehydrogenase, biotin/avidin, spin labels.
In some embodiments, the invention also provides the antibody, or the use of the antibody pair in the preparation of a kit.
In some embodiments, the invention also provides methods of making the antibodies.
Embodiments of the present invention will be described in detail with reference to examples.
EXAMPLE 1 preparation of monoclonal antibodies to the novel crown N protein
1. Immunizing animals
A BALB/c mouse which is 8-12 weeks old and has the same line with myeloma cells is taken, 100 mu g of protein-containing 2019-nCoV N protein recombinant antigen and the same amount of Freund's complete adjuvant are fully and uniformly mixed and injected into the abdominal cavity of the mouse, 100 mu g of protein-containing 2019-nCoV N protein recombinant antigen and the same amount of Freund's incomplete adjuvant are fully and uniformly mixed every 2 weeks, and the mixture is injected into the abdominal cavity of the mouse for multiple times to strengthen the immunity. By detecting mouse serum (indirect ELISA method), the antibody with titer above 1: 2000 can be used for fusion, 3 days before fusion, the antibody can be boosted again in abdominal cavity of mouse, and the dosage is 50 μ g/mouse.
2. Preparation of feeder cells
BALB/c mouse peritoneal macrophages were used as feeder cells. Before fusion 1Day, BALB/c mouse neck-pulled to death, soaking in 75% alcohol, cleaning in ultra-clean bench, cutting off abdominal skin with scissors under aseptic operation, exposing peritoneum, injecting 5mL of RPMI 1640 basic culture solution into abdominal cavity with syringe, repeatedly washing, recovering washing solution, centrifuging at 1000rpm for 5min, standing precipitate, screening with RPMI 1640 culture solution (in complete culture solution of RPMI 1640 containing HAT), re-suspending, adjusting cell concentration to 1 × 105Add to 96-well plate at 150. mu.L/well, 37 ℃ with 5% CO2The culture was carried out overnight.
3. Preparation of immune spleen cells
Three days after the last immunization of the mice, the spleen is taken out under the aseptic condition, placed in a plate, washed once by RPMI 1640 basic culture solution, placed on a nylon net of a small beaker, ground and filtered to prepare cell suspension. Centrifuging, discarding supernatant, resuspending RPMI 1640 basic culture solution, repeating the steps three times, and counting.
4. Cell fusion
(1) Respectively putting 40mL HAT culture solution, 15mL DMEM serum-free culture solution and 1mL 50% PEG (M12000) in a water bath at 37 ℃ for pre-warming;
(2) respectively taking mouse myeloma cells Sp2/0 (stored by Roc biology Ltd.) (2-5 multiplied by 10)7) The above immune spleen cell (10)8) The suspension is added into a 50mL centrifuge tube for even mixing, and DMEM serum-free culture solution is added to the centrifuge tube until the volume is 40 mL. Centrifuging for 10 min, pouring out the supernatant, and mixing;
(3) the centrifuge tube was placed in pre-warmed water at 37 ℃ and 0.7mL of pre-warmed 50% PEG solution was allowed to stand for 90 seconds. Immediately dropwise adding 15mL of prewarmed serum-free culture solution at 37 ℃;
(4) DMEM serum-free culture solution is supplemented to 40mL, centrifugation is carried out for 10 minutes, and the supernatant is poured out. Adding 40mL HAT culture solution containing 15% -20% fetal calf serum. The mixture was pipetted into wells of 4 96-well cell culture plates containing feeder cells, 2 drops per well, and cultured in an incubator at 37 ℃ in 7% CO 2.
5. Selective culture of hybridoma cells
After being treated by PEG, the immune mouse spleen cell and the mouse myeloma cell form a mixture of a plurality of cell components, wherein the cell components comprise unfused myeloma cells and immune spleen cells; a corekaryon of myeloma cells and a corekaryon of immune spleen cells, and a heterokaryon of myeloma cells and immune spleen cells. Only the latter can form hybridoma cells. For this purpose, it is necessary to remove unfused cells and homologously fused coenckaryons from the various cell mixtures and to select for true hybrid cells. Therefore, the cells were cultured with the HAT medium on days 1, 3, 5, and 7 after cell fusion.
6. Detection of specific antibodies and hybridoma cell cloning
And (3) sucking the supernatant of each culture well, and detecting the culture wells containing the antibodies which can specifically recognize the 2019-nCoV N protein recombinant antigens in the culture solution by using an indirect ELISA method. And (2) identifying the cross reactivity of the cell culture supernatant by adopting an indirect ELISA method, coating a 96-well plate with the 2019-nCoV N protein recombinant antigen, sealing, adding a hybridoma cell culture solution supernatant for incubation, adding a secondary antibody, measuring a reaction value of 405nm, selecting a cell strain with a higher reaction value (more than 0.5) to prepare an antibody, and performing a next round of screening experiment. The following antibodies with better reactivity were obtained by screening.
Example 2 identification of antibody binding fragments
Respectively coating micropores with 2019-nCoV N protein recombinant antigens with different fragments, taking PBS + 20% NBS as a diluent, diluting a monoclonal antibody to a concentration of 1ug/ml, taking goat anti-mouse IgG-HRP as a secondary antibody, and determining the monoclonal antibody fragments according to the reaction condition of each monoclonal antibody to different antigens. Through statistics, the antibodies obtained by screening are respectively directed to the following fragments:
TABLE 1
Figure BDA0003257231130000061
The reaction conditions of the eleven-strain antibodies combined with the 44-180aa fragment on the fragment are extracted as shown in Table 2:
TABLE 2
Antibodies 6I3 9D2 4C9 5C3 1A6 1E5 8E4 6K1 6A5 7R1 5S7
Reactivity 2.362 2.616 2.491 2.493 2.486 2.528 2.941 2.949 2.444 2.552 2.778
Reactivity, OD in Table 2405The reaction value.
Example 3 paired screening
The above antibodies were used for coating and labeling, respectively, and the experimental procedure was as follows:
1. labeling of the novel crown N antibody: adding 5ml of 4/ten thousand colloidal gold into 30-40ul of 0.2M K2CO3Stirring for 5min, adding new crown N labeled antibody (the volume of the added antibody is 50 mug/antibody concentration), stirring for 5min, and adding 50ul 10% BSA to block and stop labeling; centrifuging at 10000rpm for 7min, removing supernatant, dissolving precipitate with gold seed complex solution, and diluting to 0.5ml with gold seed complex solution (1/10 volume of colloidal gold solution).
2. Preparing a gold seed working solution: and (3) preparing gold seed working solution by using gold seed complex solution to concentrate the new crown N-labeled antibody gold according to the dilution ratio of 20%, and spreading the gold seed working solution on glass fiber.
3. Preparing dried gold seeds: putting the paved gold seeds into a freeze dryer for freeze drying (1-2h) or a drying room at 37 ℃ for drying overnight.
4. New crown N antibody coating: assembling the nitrocellulose membrane and the PVC base plate for later use; diluting the new crown N coating antibody to 1.0-1.5mg/ml, uniformly scribing on NC membrane with gold spraying membrane drawing instrument, and placing in 37 deg.C incubator for 60 min.
5. Preparing a gold label strip: and cutting the gold label into strips according to the required width by using a strip cutting machine, and adding the sample for detection after assembly.
6. Detection of
(1) Quality control product: 2019-nCoV N protein recombinant antigen, and diluting to 1ng/ml by using PBS to carry out antibody pairing primary screening;
(2) the detection method comprises the following steps: and judging the color development reading value by naked eyes according to the color card comparison.
7. Results (detection of one antibody per fragment):
tables 3-13B 8 test results as coated antibody
Labeled antibodies 6I3 9D2 4C9 5C3 1A6 1E5 8E4 6K1 6A5 7R1
Quality control product C8 C8 C7 C8 C8 C8 C8 C8 C8 C7
PBS C9 B C8 C9 C9 B C9 C9 B B
Labeled antibodies 5S7 6D9 4B7 1B5 2F4 7C5 5D9 4D1 6D5 4C6
Quality control product C7 C8 C8 C8 C8 C8 C8 C8 C7 C7
PBS B C9 C9 B C9 B C9 C9 C8 C8
Tables 3-25C 3 test results as coated antibodies
Labeled antibodies 6I3 9D2 4C9 3B8 1A6 1E5 8E4 6K1 6A5 7R1
Quality control product C4 C4 C4 C8 C4 C3 C5 C5 C4 C3
PBS B B B C9 B B B B B B
Labeled antibodies 5S7 6D9 4B7 1B5 2F4 7C5 5D9 4D1 6D5 4C6
Quality control product C3 C7 C7 C8 C8 C8 C7 C7 C8 C8
PBS B B B B C9 B B B C9 B
Tables 3-34B 7 test results for coated antibodies
Figure BDA0003257231130000071
Figure BDA0003257231130000081
Tables 3-41B 5 As the results of detection of coated antibody
Labeled antibodies 6I3 9D2 4C9 5C3 1A6 1E5 8E4 6K1 6A5 7R1
Quality control product C8 C6 C7 C6 C8 C6 C7 C9 C9 C6
PBS C9 B C9 B C9 B C9 C9 C9 B
Labeled antibodies 5S7 6D9 4B7 3B8 2F4 7C5 5D9 4D1 6D5 4C6
Quality control product C6 C7 C7 C7 C7 C8 C7 C7 C8 C8
PBS B C8 C9 C7 C8 C9 B C9 B B
Tables 3-54C 6 test results as coated antibodies
Labeled antibodies 6I3 9D2 4C9 5C3 1A6 1E5 8E4 6K1 6A5 7R1
Quality control product C8 C7 C7 C7 C8 C9 C7 C9 C9 C8
PBS B C9 C9 B B C9 B C9 B B
Labeled antibodies 5S7 6D9 4B7 1B5 2F4 7C5 5D9 4D1 6D5 3B8
Quality control product C9 C7 C8 C8 C7 C8 C7 C7 C8 C8
PBS B C8 C9 C9 C8 C9 B C9 B B
In tables 3-1, 3-2, 3-3, 3-4 and 3-5, the letter B indicates no color development (no detection), the number following the letter C indicates color development, and the larger the number, the weaker the color development (lower activity).
From the detection result, the antibody combined with the 44-180aa section shows higher activity in detection performance, so that the antibody in the section is further subjected to fragment identification.
Example 4 dominant antibody further fragment identification
Carrying out small fragment expression on a 44-180aa fragment of the 2019-nCoV N protein recombinant antigen, respectively coating micropores with the 2019-nCoV N protein recombinant antigens with different fragments, diluting a monoclonal antibody to a primary antibody concentration of 1ug/ml by using PBS + 20% NBS as a diluent, and determining the monoclonal antibody fragment according to the reaction condition of each monoclonal antibody to different antigens by using goat anti-mouse IgG-HRP as a secondary antibody, wherein the specific data are as follows:
TABLE 4-1
Figure BDA0003257231130000082
Figure BDA0003257231130000091
TABLE 4-2
Antibody numbering 8E4 6K1 6A5 7R1 5S7
44-180 2.941 2.949 2.444 2.552 2.778
44-84 0.018 0.059 0.014 0.017 0.016
65-103 0.025 0.058 0.013 2.056 2.366
96-136 0.013 0.036 0.014 0.010 0.017
130-180 0.016 0.053 0.011 0.014 0.015
Antibody recognition segments 44-180 44-180 44-180 65-103 65-103
From the above results, the 9D2, 7R1 and 5S7 antibodies further recognized and bound 65-103aa, and the rest antibodies recognized only 44-180 aa.
Example 5 dominant antibody pairing Performance further validation
The preparation processes of antibody labeling, coating, assembling and the like are shown in steps 1-5 of example 3.
Detection of
(1) Quality control product: 2019-nCoV N protein recombinant antigen, diluted to 25ng/ml, 2ng/ml, 500pg/ml, 100pg/ml, 25pg/ml, 10pg/ml with PBS;
(2) the detection method comprises the following steps: and judging the color development reading value by naked eyes according to the color card comparison.
Results
1. Activity: the following examples illustrate that recombinant antigen expressed in E.coli is detected at 100pg/ml (C7+ development) and at 25pg/ml (C8 or C8+ development), with a minimum detection limit of 10 pg/ml.
TABLE 5
Figure BDA0003257231130000092
Figure BDA0003257231130000101
2. Specificity:
the three example pairs are respectively used for carrying out colloidal gold color development tests on 300 collected normal human nose swabs, 300 collected normal human pharynx swabs and 300 collected normal human saliva samples, and the specificity is 100%.
3. And (3) cross reaction:
various pathogens such as adenovirus, cytomegalovirus, EB virus, measles virus, mumps virus, mycoplasma pneumoniae, parainfluenza virus, respiratory tract and cytovirus, rotavirus, varicella-zoster virus, influenza A/B virus and the like are diluted in different concentrations respectively, and the three examples are paired and tested, so that cross reaction does not exist.
4. Positive and negative pairing:
the three example pairings were exchanged between labeled and coated antibodies, and the pairing performance remained comparable.
EXAMPLE 6 dominant antibody Productivity
The present invention also provides the antibody preparation scheme as described above, and the antibody that binds to the 44-180aa fragment, but does not bind to the 44-84aa fragment, the 65-103aa fragment, the 96-136aa fragment, and the 130-180aa fragment is prepared by immunizing with the 44-180 th amino acid fragment of SARS-CoV-2 nucleocapsid protein as immunogen, and evaluated for OD by ELISA, for example, by reactive screening405The antibodies 1COV19-8 and 3COV19-17 of ≧ 0.5 have the same performances, such as high sensitivity, good specificity and no cross reaction.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims (10)

1. An antibody or antigen-binding fragment thereof, wherein the antibody binds to an amino acid fragment from position 44 to 180 of the SARS-CoV-2 nucleocapsid protein.
2. The antibody or antigen-binding fragment thereof of claim 1, which does not bind to the amino acid fragments at positions 44-84, 65-103, 96-136, and 130-180 of the SARS-CoV-2 nucleocapsid protein.
3. An antibody pair comprising antibody 1 according to claim 1 or 2, and antibody 2 according to claim 1 or 2, or antibody 2 that binds to an amino acid fragment 65 to 103 of the nucleocapsid protein of SARS-CoV-2.
4. A fusion protein comprising a fragment of amino acids 44-180 of the SARS-CoV-2 nucleocapsid protein.
5. A nucleic acid molecule encoding the fusion protein of claim 4.
6. An expression vector construct comprising the nucleic acid molecule of claim 5.
7. An isolated host cell comprising the expression vector construct of claim 6.
8. A kit comprising the antibody or antigen-binding fragment thereof of claim 1 or 2, or the antibody pair of claim 3, or the fusion protein of claim 4.
9. Use of an antibody or antigen-binding fragment thereof according to claim 1 or 2, or an antibody pair according to claim 3 in the manufacture of a kit.
10. A method of producing the antibody of claim 1, comprising: 1) immunizing an animal with an antigen or hapten comprising a fragment of amino acids 44-180 of the SARS-CoV-2 nucleocapsid protein; and 2) obtaining an antibody that binds to an amino acid fragment from positions 44-180 of the SARS-CoV-2 nucleocapsid protein from ascites fluid of said animal.
CN202111063235.1A 2021-09-10 2021-09-10 Novel crown antibody or antigen binding fragment thereof and application thereof Pending CN113603771A (en)

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