37 results about "Serodiagnoses" patented technology

The invention discloses a monoclonal antibody for distinguishing a hog cholera lapinized virus vaccine strain and a hog cholera lapinized virus epidemic strain and application of the monoclonal antibody, and belongs to the field of immune globulin. The E2 protein monoclonal antibody or the antigen binding fragment thereof comprises a heavy chain variable region (SEQ ID No.1) and a light chain variable region (SEQ ID No.3). The invention also discloses an ELISA method for identifying and distinguishing hog cholera lapinized virus vaccine strains and epidemic strains by using the E2 protein monoclonal antibody. The monoclonal antibody disclosed by the invention has a specific reaction with the swine fever virus epidemic strain and does not react with the swine fever lapinized virus vaccine strain, and the swine fever lapinized virus vaccine strain and the epidemic strain can be accurately identified and distinguished by utilizing an ELISA competition method established by the monoclonal antibody. The monoclonal antibody provided by the invention can be used in the fields of CSFV immunization, serological diagnosis of wild viruses, immune effect evaluation, related experiments and the like, and provides antibody resources for effective detection and purification of CSFV.

The invention discloses an anti-pestivirus broad-spectrum neutralizing monoclonal antibody and application thereof, and belongs to the field of immune globulin. The anti-pestivirus monoclonal antibody or the antigen binding fragment thereof comprises a heavy chain variable region (SEQ ID No.1) and a light chain variable region (SEQ ID No.3). The monoclonal antibody provided by the invention can identify hog cholera virus and all known plague virus members (BVDV1, BVDV2, BDV, HoBiPeV, AydinPeV and OVPV) capable of infecting cattle and sheep at present, has good neutralizing ability, and can be prepared into a diagnostic product for plague virus antigen-antibody detection. The monoclonal antibody and a diagnostic product developed based on the monoclonal antibody can be used for serological diagnosis and immune effect evaluation of pestivirus, pestivirus pathogen detection of experimental serum products and the like, and have wide application prospects in the fields of clinical diagnosis and the like.

The invention discloses a serological diagnosis model containing PRO-C3 and application of the serological diagnosis model in preparation of a detection reagent for the fibrosis degree of a CHB patient. The serum combined detection method for PRO-C3, PLT and ALP provided by the invention is a sensitive and efficient method for detecting the fibrosis degree of a CHB patient. Therefore, the PRO-C3 combined with the PLT and the ALP can be used as a novel serological diagnosis model for diagnosing the fibrosis degree of the CHB patient. The serological diagnosis model containing PRO-C3 can be used for preparing a detection reagent and / or a kit for detecting the fibrosis degree of a CHB patient by detecting the fibrosis degree of a quantifiable index liver tissue and sensitively and efficiently detecting the remarkable fibrosis, so that the serological diagnosis model containing PRO-C3 can be used for preparing the detection reagent and / or the kit for detecting the fibrosis degree of the CHB patient.

The invention discloses a type 2 GAstV capsid protein monoclonal antibody and an antigen epitope peptide of the type 2 GAstV capsid protein monoclonal antibody. The monoclonal antibody is prepared by immunizing a mouse with capsid protein GAstV Cap of the type 2 goose astrovirus as an antigen, and is named as 1F1; the monoclonal antibody 1F1 comprises a heavy chain variable region and a light chain variable region, and the amino acid sequences of the heavy chain variable region and the light chain variable region are sequentially shown as SEQ ID No.3 and SEQ ID No.5. In order to determine the B cell antigen epitope of the screened monoclonal antibody, the invention also constructs a GAstV Cap truncated fusion protein, and the antigen recognition epitope is determined through indirect ELISA and Western blotting tests, so that screening is carried out step by step until the shortest linear epitope recognized by the monoclonal antibody is determined, and the amino acid sequence of the shortest linear epitope is shown as SEQ ID No.10. Therefore, the monoclonal antibody and the antigen epitope of the monoclonal antibody can be applied to research on structures and functions of GAstV capsid proteins and preparation of serological diagnostic tools and epitope vaccines.

The invention relates to a monoclonal antibody DIDA55 aiming at hog cholera virus, and a preparation method and application thereof, belonging to the field of medical preparations. The monoclonal antibody DIDA55 or an antigen binding fragment thereof comprises a heavy chain variable region and a light chain variable region, amino acid sequences of LCDR1, LCDR2 and LCDR3 in a light chain variable region of the antibody are shown as 24th to 34th, 50th to 56th and 89th to 97th in SEQ ID No: 4; amino acid sequences of HCDR1, HCDR2 and HCDR3 in a heavy chain variable region of the antibody are shown as the 31st to 35th, the 50th to 65th and the 95th to 102th of SEQ ID No: 5. The monoclonal antibody provided by the invention can be used in the fields of swine fever E2 protein labeled subunit vaccine immunity, serological diagnosis of wild strains, swine fever vaccine immune effect evaluation, related experiments and the like, and provides antibody resources for prevention, control and purification of CSF.

The application belongs to the technical field of biology and particularly relates to an ELISA kit for detecting chicken astrovirus type II antibodies and a preparation method. The Cell-ELISA experiment is carried out by using LMH cells infected with chicken astrovirus type II to detect the chicken astrovirus type II antibodies. The method has no cross reactivity with positive serum of Newcastle disease virus, avian influenza virus, chicken infectious anemia virus, avian leukosis virus, Marek's virus and chicken infectious bursal virus, which indicates that the method has good specificity. The Cell-ELISA method is used to detect the chicken serum sample to be detected by using whole virus infection, and is assembled into a kit for measuring chicken astrovirus antibodies in serum. The kit can be used for serological diagnosis of chicken astrovirus type II infection, monitoring of the level of antibodies, epidemiological investigation and the like, and provides a novel and effective detection means for prevention and treatment of chicken astrovirus type II.

The invention discloses a human expression optimized Nipah virus N gene and application thereof in preparation of Nipah pseudovirus, belongs to the technical field of biology, and constructs a segment of Nipah virus N gene sequence optimized by human cell expression codons and constructs a recombinant vector pcDNA3.1-NiV-N-opti. The recombinant vector pcDNA3.1-NiV-N-opti is used as a pseudovirus expression vector, the recombinant vector pcDNA3.1-NiV-N-opti and pseudovirus packaging plasmids are used for preparing the kit for the nipah pseudovirus, the nipah pseudovirus can be efficiently obtained, the titer of the obtained nipah pseudovirus is higher than that of the nipah pseudovirus packaged by an original sequence, and an unexpected technical effect is achieved. Besides, the Nipah pseudovirus has His, Myc and EGFP marks, the preparation effect of the pseudovirus can be visually observed, and the Nipah pseudovirus can be used for Nipah serological diagnosis, virus neutralizing antibody evaluation and the like and has a good application prospect.

The invention discloses a recombinant tetanus toxin protein rTT as well as a preparation method and application thereof, the recombinant protein sequentially contains a His tag, a modified exogenous polypeptide and two tetanus toxin fragments connected in series through flexible polypeptides from the N end to the C end, the two tetanus toxin fragments connected in series form two intramolecular disulfide bonds in a molecule through double mutation, and the tetanus toxin fragments are connected in series through flexible polypeptides. Coding nucleotide of the recombinant protein is expressed by escherichia coli BL21 (DE3), induced at low temperature and purified, and target protein with the purity larger than or equal to 95% can be obtained. A subunit vaccine prepared from the protein and a two-way oil adjuvant ISA201 enables mice to achieve 100% protection under 100 LD50 challenge dose, the protection effect is better than that of truncated tetanus toxin heavy chain fragment TTc protein, and the recombinant protein can be used for tetanus prevention vaccines and serological diagnostic reagents.

The present invention discloses a monoclonal antibody for distinguishing a lapinized attenuated vaccine strain of classical swine fever from an epidemic strain and its application, belonging to the field of immunoglobulins. Specifically disclosed is an E2 protein monoclonal antibody or an antigen-binding fragment thereof, including a heavy chain variable region (SEQ ID No.1) and a light chain variable region (SEQ ID No.3). The present invention also discloses an ELISA method for distinguishing a lapinized attenuated vaccine strain of classical swine fever from an epidemic strain using the E2 protein monoclonal antibody. The monoclonal antibody of the present invention specifically reacts with an epidemic strain of classical swine fever virus, but does not react with a lapinized attenuated vaccine strain of classical swine fever. The ELISA competition method established using the monoclonal antibody can accurately distinguish a lapinized attenuated vaccine strain of classical swine fever from an epidemic strain. The monoclonal antibody of the present invention can be used in the fields of serological diagnosis of CSFV immunization and wild virus, immune effect evaluation, and related experiments, and provides antibody resources for effective detection and purification of CSFV.

The present invention relates to a chimeric protein consisting of a specific region of a protein selected from the group consisting of LIC 10123, LIC 13059, LIC 13050, LIC 12615, LIC 11636, LIC 11352, LIC 11122, LIC 11089, LIC 10713 and LIC 13434, which is demonstrated to be conservative and present on the surface of LIC 10123, LIC 13059, LIC 13050, LIC 12615, LIC 11636, LIC 11352, LIC 11122, LIC 11089, LIC 10713 and LIC 13434, wherein the specific region consists of the amino acid sequence defined by SEQ ID NO: 2, 4, 6, 7, 9, 11, 13, 14, 16, 18, 20 and 22 The invention further relates to a host microbial cell comprising a chimeric gene consisting of the nucleotide sequence shown in SEQ ID NO: 25, said chimeric gene and an expression cassette. In addition, the invention relates to a method for obtaining said chimeric protein and a leptospirosis serological diagnostic kit comprising the chimeric protein of the invention. Furthermore, the present invention relates to an in vitro method for the early serological diagnosis of leptospirosis and the use of said chimeric protein for the early serological diagnosis of leptospirosis by detecting IgM and / or IgG antibodies in a serum sample from a patient suspected of having leptospirosis.

The present invention relates to Cap 38～228 The technical field of protein preparation, in particular, relates to a method for preparing high-purity porcine circovirus type 4 Cap protein. Steps include S1. constructing a prokaryotic expression vector pET-28a-His-SUMO-Cap with a double tag based on the nucleotide sequence of PCV4 Cap protein and His-SUMO tag. 38～228 ; S2. using pET‑28a‑His‑SUMO‑Cap 38～228 Transformed into E. coli competent cells BL21, induced expression with IPTG, and optimized expression conditions to produce the target protein His-SUMO-Cap 38～228 ; At the same time, the target protein His-SUMO-Cap 38～228 Purification; S3.His-SUMO-Cap 38～228 After SUMO protease cleavage, the His-SUMO tag was removed again using a Ni-NTA affinity chromatography column to obtain Cap 38～228 The present invention can effectively prepare high-purity PCV4Cap 38～228 The protein has a purity greater than 95%, providing PCV4Cap for serological diagnosis, polyclonal or monoclonal antibodies to Cap protein, and subunit vaccine development. 38～228 Technical basis for protein preparation.

The present invention provides a variant pseudorabies virus (PRV) gC-gD epitope concatemer and its application. The amino acid sequence of the variant pseudorabies virus gC-gD expression concatemer is shown in SEQ ID NO.1, and the nucleotide sequence of its encoding gene is shown in SEQ ID NO.2. The present invention uses the variant pseudorabies virus gC-gD epitope concatemer to establish an indirect ELISA detection method for PRV neutralizing antibodies with strong specificity, high sensitivity and good repeatability. The method can fully meet the serological diagnosis requirements of pig herds in pig farms where PRV wild virus is prevalent and pig farms where PRV wild virus has been purified, laying a certain foundation for the development of a new PRV polypeptide vaccine.

The present application relates to a kind of monoclonal antibody DIVA55 for swine fever virus in the field of medical preparation and its preparation method and application.The monoclonal antibody DIVA55 or its antigen-binding fragment of the present application includes heavy chain variable region and light chain variable region;The amino acid sequences of LCDR1, LCDR2 and LCDR3 in the light chain variable region of the antibody are as shown in the 24th to 34th, 50th to 56th, 89th to 97th of SEQ ID No:4;The amino acid sequences of HCDR1, HCDR2 and HCDR3 in the heavy chain variable region of the antibody are as shown in the 31st to 35th, 50th to 65th, 95th to 102nd of SEQ ID No:5.The monoclonal antibody of the present application can be used in the field such as swine fever E2 protein marker subunit vaccine immunization and wild strain serological diagnosis, swine fever vaccine immunization effect evaluation and related experiments, provides antibody resource for CSF prevention and control and purification.

The invention discloses a novel anti-echinococcus monoclonal antibody, a hybridoma cell strain and application of the novel anti-echinococcus monoclonal antibody, and belongs to the technical field of biomedicine and immunology. The preservation number of the hybridoma cell strain Anti-Em-11 disclosed by the invention is CGMCC (China General Microbiological Culture Collection Center) No. 46598. According to the present invention, the specific monoclonal antibody is successfully prepared and identified, and Western blot and indirect immunofluorescence experiments prove that the obtained monoclonal antibody has high specificity on the recombinant protein. The invention lays a solid foundation for serological diagnosis of the echinococcosis and remarkably enriches the existing serological detection technical system.

The invention relates to the field of veterinary protozoology and methods for producing antigens, particularly for the diagnosis of Surra Su-Auru in animals. The objective of the invention is to develop a method for producing a highly sensitive trypanosomal antigen for the serological diagnosis of Surra (Su-Auru) in animals. The problem is solved by the fact that the method for obtaining trypanosome antigen for serological diagnostics of Surra (Su-Auru) in animals involves infecting rabbits intratesticularly with live trypanosomes of the T species. evansi, removal of the spleen 2-3 days after infection, total bleeding 8-10 days after splenectomy (parasitemia -80-90%), blood is collected in a wide vessel with 2% sodium citrate in physiological solution with constant stirring with a glass rod, at the rate of 1 part blood to 2 parts solution, settling of citrated blood in the refrigerator for 18-24 hours, centrifugation and separation of the middle layer from the sediment from the supernatant, 2-3 times washing of trypanosomes in physiological solution, at 3000-5000 rpm, for 10 minutes each, disintegration of the centrifugate by ultrasound at a frequency of 22 kHz, power of 60 W / cm2 for 8-12 minutes, followed by centrifugation of the disintegrate at 8000-10000 rpm for 20-30 minutes and collection of sediment (endoantigen), treatment of the supernatant with TCA, collection of the precipitated sediment (exoantigen), batches of sediment are mixed 10:1. The technical result provided by the utility model is expressed in the development of a method for obtaining a highly sensitive trypanosomal antigen for the serological diagnosis of Surra (Su-Auru) in animals.

The present invention discloses an ELISA antibody detection kit for avian infectious bronchitis virus nsp4 and its application, belonging to the field of immunological detection methods. The kit uses recombinant non-structural protein 4 of avian infectious bronchitis virus as the coating antigen; the nucleotide sequence of the coding gene of the recombinant non-structural protein 4 of avian infectious bronchitis virus is as shown in SEQ ID NO: 3, and its amino acid sequence is as shown in SEQ ID NO: 2. The present invention has successfully established an indirect ELISA detection kit and method for antibodies against non-structural protein 4 of avian infectious bronchitis virus. This method has high specificity, strong sensitivity, and good repeatability. The coefficient of variation of within-batch repeatability is 4.6%, and the coefficient of variation of between-batch repeatability does not exceed 7%. It can be applied to the detection of large-scale serum samples, providing a new selection method for serological diagnosis and immune monitoring of IBV, and having good prospects for popularization and application.

The invention discloses a serology-based rapid diagnosis method for juvenile tuberculosis. The invention provides an economical and efficient method for diagnosing tuberculosis of teenagers. Based on serum proteomics of clinically active teenager tuberculosis patients, a rapid tuberculosis diagnosis method based on serology is found. According to the present invention, through a variety of machine learning algorithms, the combination of the three proteins such as the apolipoprotein A1 (Apolipoprotein A-I, APOA1), the hemoglobin subunit alpha (Hemoglobin subunit alpha-1, HBA1) and the hemoglobin subunit beta (Hemoglobin subunit beta, HBB) has the highest accuracy and the highest sensitivity in the teenager tuberculosis diagnosis process, such that the combination can be adopted as the serological diagnosis marker of the teenager tuberculosis; the invention provides a new method for rapid diagnosis of juvenile tuberculosis.

The invention discloses a broad-spectrum neutralizing monoclonal antibody for identifying seven pestivirus, and belongs to the field of immune globulin. The anti-pestivirus monoclonal antibody or the antigen binding fragment thereof comprises a heavy chain variable region (SEQ ID No.1) and a light chain variable region (SEQ ID No.3). The monoclonal antibody reacts with BVDV1, BVDV2, CSFV, BDV, HoBiPeV, AydinPeV and OVPV, is wider in spectrum compared with other plague virus monoclonal antibodies, can recognize all known plague virus members infecting cattle and sheep at present, can also recognize the plague virus member CSFV, has good neutralizing capacity, and can be prepared into diagnostic reagents and products clinically used for plague viruses. The antibody disclosed by the invention can be used for serological diagnosis and immune effect evaluation of pestivirus, pestivirus pathogen detection of serum products for experiments and the like, and has a wide application prospect in the fields of clinical diagnosis and the like.

The application discloses a monoclonal antibody of a porcine rotavirus VP6 protein, an epitope of the monoclonal antibody and application of the monoclonal antibody. The monoclonal antibody can specifically recognize a linear B cell epitope on the VP6 protein, and a core sequence of the epitope is TTRLSFQLVR. The antibody has high affinity and high specificity, and can cross-react with porcine rotaviruses of various genotypes such as G5, G9 and G11. The application further includes an indirect ELISA detection kit containing the monoclonal antibody, and application of the linear epitope in detection of porcine rotaviruses, development of vaccines and research on functions of viral proteins. The application provides an important tool and theoretical basis for serological diagnosis, vaccine evaluation and etiological research of porcine rotaviruses.

The present invention discloses the use of a recombinant protein in the preparation of a product for diagnosing or assisting in the diagnosis of IgA nephropathy. Specifically, it discloses the use of a protein with an amino acid sequence of SEQ ID No.1 in the preparation of a product for diagnosing or assisting in the diagnosis of IgA nephropathy. The present invention uses a recombinant baculovirus containing the gene encoding human glycosyltransferase B3GNT6(43-384) to infect insect cells, obtaining a secreted form of glycosyltransferase B3GNT6(43-384), which can efficiently and specifically recognize the Tn antigen in the hinge region of Gd-IgA1. Based on this, the present invention has developed a novel chemical enzyme method technology for serological diagnosis of IgA nephropathy. This technology can effectively distinguish IgA nephropathy patients, healthy controls, and other nephropathy controls, with high stability, good repeatability, and the characteristics of non-invasive, rapid, specific, and sensitive, having a very broad clinical application prospect and important significance.

The present invention discloses a broad-spectrum neutralizing monoclonal antibody that recognizes 7 kinds of pestiviruses, belonging to the field of immunoglobulins. Specifically disclosed are anti-plague virus monoclonal antibodies or antigen-binding fragments thereof, including a heavy chain variable region (SEQ ID No.1) and a light chain variable region (SEQ ID No.3). The monoclonal antibody of the present invention reacts with BVDV1, BVDV2, CSFV, BDV, HoBiPeV, AydinPeV and OVPV, and is broader in spectrum than other pestivirus monoclonal antibodies, and can recognize all pestivirus members currently known to infect cattle and sheep, and can also recognize pestivirus member CSFV, and has good neutralizing ability, and can be made into diagnostic reagents and products for pestivirus in clinical use. The antibody of the present invention can be used for serological diagnosis of pestiviruses, evaluation of immune effects, and detection of pestivirus pathogens in experimental serum products, etc., and has broad application prospects in clinical diagnosis and other fields.

The invention provides an anti-eperythrozoon ovine HSP70 protein polyclonal antibody as well as a preparation method and application thereof, and belongs to the technical field of bioengineering. The polyclonal antibody disclosed by the invention is prepared by immunizing an animal with an immunogen containing 109th-266th amino acids of the eperythrozoon ovine HSP70 protein, and has the characteristics of high titer and strong specificity. The preparation method of the polyclonal antibody comprises the steps of gene synthesis, protein expression and purification, animal immunization, antibody purification and the like. The invention also provides an application of the polyclonal antibody in immunological detection such as Western Blot, ELISA (Enzyme-Linked Immunosorbent Assay) and the like, and a detection kit containing the polyclonal antibody. The polyclonal antibody provides a core reagent for serological diagnosis of sheep eperythrozoonosis, and has important application value.

This invention belongs to the field of reagent detection technology and discloses a diagnostic kit for P200 type pemphigus. The kit comprises human dermal extract protein strips, LM521 / LM421 / LM411 / LM111 recombinant protein strips, a positive control, a negative control, enzyme-labeled IgG antibody, enzyme-labeled IgA antibody, reaction buffer, washing buffer, and enzyme matrix solution. This invention simplifies the complex immunoblotting technique, using human dermal extract and various LMγ1 recombinant protein mixtures as antigens, and simultaneously analyzing IgG and IgA autoantibodies. It comprehensively solves the serological diagnostic problem of P200 type pemphigus in one step.

The invention provides a mycoplasma bovis specific antigen epitope peptide and application thereof in antibody detection, and the amino acid sequence of the antigen epitope peptide is SEQ ID NO: 1. Bioinformatics prediction and serological verification are carried out on mycoplasma bovis immunogenic protein, the antigen epitope peptide highly associated with antibody reaction specificity is obtained through screening, a high-specificity mycoplasma bovis antibody detection method can be established by using the epitope peptide, the detection specificity is 100%, the sensitivity is 98.8%, and the detection time is short. And an effective tool is provided for serological diagnosis of mycoplasma bovis infection.

The invention provides an African swine fever virus antigen, a detection kit and application. The antigen of the African swine fever virus is an African swine fever virus C-type lectin protein, and the amino acid sequence of the African swine fever virus C-type lectin protein is as shown in SEQ ID NO. 1. In the antigens of the African swine fever virus (ASFV), the protective immunity of the African swine fever virus (ASFV) may be that the serotype specificity is inhibited by blood adsorption, and in the ASFV protein, the C-type lectin is a necessary protein for mediating the serological specificity of the HAI. Therefore, the C-type lectin is used as a target protein for ASFV serological diagnosis, and the antigen characteristic of the C-type lectin protein is utilized, so that an antibody ELISA detection method with application value is established, and research and development of a novel ASFV antibody ELISA detection method are facilitated.

The invention provides a neutralizing epitope polypeptide of grouper nervous necrosis virus and application of the neutralizing epitope polypeptide in serological diagnosis test paper, and the amino acid sequence of the neutralizing epitope polypeptide is SEQ ID NO: 1 or SEQ ID NO: 2. On the other hand, the invention also provides a serological diagnosis test strip for the nervous necrosis virus disease of the grouper, wherein the NNV capsid protein neutralizing epitope polypeptide is used as a detection line. The antigen polypeptide used by the test strip is an NNV capsid protein neutralizing epitope specific fragment, the antigen recognition effect is improved by optimizing the mixing ratio, cross reaction with other pathogen positive serum of grouper is avoided, and the detection accuracy is ensured.

The invention relates to the technical field of antibodies, and particularly provides an antibody specifically bound with African swine fever virus p62 protein and application. The antibody or the antigen binding fragment thereof comprises a heavy chain variable region with an amino acid sequence as shown in SEQ ID NO.1 and a light chain variable region with an amino acid sequence as shown in SEQ ID NO.3, p62 protein can be recognized with high specificity, and the blocking rate of the antibody reaches 90% or above. The antibody can exist in various forms such as a monoclonal antibody and a single-chain antibody, and biological materials such as coding nucleic acid, expression vectors and recombinant cells of the antibody can be produced on a large scale. Based on the antibody or the antigen binding fragment thereof, the antibody or the antigen binding fragment thereof can be used for preparing an African swine fever virus detection product, is especially suitable for constructing a blocking ELISA antibody detection kit with high sensitivity and strong specificity, and provides an effective tool for serological diagnosis and monitoring of African swine fever.

The present invention discloses a porcine epidemic diarrhea virus S1 protein and its application. The present invention also discloses a magnetic particle chemiluminescence method for detecting PEDV IgG antibody and PEDV IgA antibody respectively using PEDV S1 recombinant protein as antigen and assembling a kit, which can effectively perform serological diagnosis and investigation on the currently popular PEDV virus, judge the PEDV antibody level and natural infection status in the pig herd, and provide a rapid and simple detection method for the prevention and treatment of PEDV virus.

The invention belongs to the technical field of biological detection, and particularly relates to a monoclonal antibody 5H4 for detecting a classical swine fever virus antibody and application of the monoclonal antibody 5H4. A heavy chain variable region of the monoclonal antibody 5H4 comprises three complementarity determining regions, and amino acid sequences of the complementarity determining regions are respectively shown as SEQ ID NO.1 to SEQ ID NO.3; the light chain variable region comprises three complementarity determining regions, and the amino acid sequences of the three complementarity determining regions are respectively shown as SEQ ID NO.4 to SEQ ID NO.6. The antibody can recognize a key antigen epitope of the classical swine fever virus E2 protein, and can be competitively blocked by a specific antibody in animal serum. A blocking ELISA detection method established based on the antibody has a detection result consistent with that of an international mainstream commercial kit, and has excellent specificity, sensitivity and repeatability. The invention provides an efficient and reliable tool for serological diagnosis of classical swine fever virus infection and vaccine immune effect evaluation.

The present invention provides a protein antigen YexI for diagnosing brucellosis, whose amino acid sequence is SEQ ID No: 1, and the nucleotide sequence of the encoding gene is SEQ ID NO: 2. The new protein antigen YexI for diagnosing brucellosis provided by the present invention and the indirect ELISA established based on the YexI antigen do not cross-react with other common pathogenic bacteria sera of cattle and sheep, and the indirect ELISA based on the YexI antigen has high specificity and good repeatability, and has a high compliance rate with imported commercial detection kits, which can reach 90.5%. The antigen protein YexI provided by the present invention can be used for serological diagnosis of bovine brucellosis, has the characteristics of high specificity, good repeatability, easy preparation of antigens and no biosafety risks, and a variety of serological diagnostic products can be developed based on the protein, providing new ideas and new means for the prevention and control of bovine brucellosis.