title: Development and partial validation of a recombinant E2-based indirect ELISA for detection of specific IgM antibody responses against classical swine fever virus.
abstract: Detecting classical swine fever virus specific antibody responses is critical for prevention and control of CSF. In this study, a ΔE2-based indirect ELISA was developed to detect specific IgM antibodies against CSFV. The optimized conditions that were determined experimentally are: a ΔE2 antigen concentration of 0.5 μg/ml, a serum sample dilution of 1/100 incubated at 37°C for 1.5 h, and a HRP conjugated rabbit anti-pig IgM dilution of 1/50,000 incubated at 37°C for 1 h. Three hundred clinical sera were tested with ΔE2-IgM-ELISA and IDEXX ELISA and the positive rates were 77.3% (232/300) and 71.7% (215/300), respectively. Concordance rate between them was 80.3% (241/300). The 59 inconsistent sera were tested further: among the 21 IDEXX ELISA +/ΔE2-IgM-ELISA - and 38 IDEXX ELISA +/ΔE2-IgM-ELISA - samples, 17 and 24 were determined positive by virus neutralization test; 15 and 25 were tested positive by ΔE2-IgG-ELISA, respectively. In addition, the E2-specific IgM antibody response in 15 vaccinated piglets could be detected 2 weeks post-vaccination and earlier than specific IgG antibody. It increased regularly and reached high levels by 6 weeks post-vaccination. The ΔE2-IgM-ELISA could be used for clinical detection and for exploring the kinetics of IgM antibody response.
authors.affiliation: Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture, National Center for Engineering Research of Veterinary Bio-products, Nanjing 210014, China.
authors.forename: Wenliang
authors.initials: W
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Mao
authors.forename: Leilei
authors.initials: L
authors.lastname: Yang
authors.forename: Bin
authors.initials: B
authors.lastname: Zhou
authors.forename: Jieyuan
authors.initials: J
authors.lastname: Jiang
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D006691:Classical Swine Fever / Q000175:diagnosis*; D006692:Classical Swine Fever Virus / Q000276:immunology*; D019411:Clinical Laboratory Techniques / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D007075:Immunoglobulin M / Q000097:blood*; D011994:Recombinant Proteins / Q000235:genetics; D013552:Swine; D014730:Veterinary Medicine / Q000379:methods*; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D000914:Antibodies, Viral; D007075:Immunoglobulin M; D011994:Recombinant Proteins; D014759:Viral Envelope Proteins; C087086:glycoprotein E2, classical swine fever virus