title: Establishment and application of a competitive enzyme-linked immunosorbent assay differentiating PCV2 antibodies from mixture of PCV1/PCV2 antibodies in pig sera.
abstract: BACKGROUND
  Porcine cirovirus type 1 (PCV1) and type 2 (PCV2) are circulating in Chinese pig herds and the infected pigs develop antibodies to both viruses. Current commercial available ELISA kits cannot differentiate PCV2-specific antibodies from the mixtures of PCV1 and PCV2 antibodies in PCV1/2-infected or PCV2-vaccinated pigs. Therefore, the need for developing PCV2-specific ELISA methods is urgent to evaluate PCV2 antibody level in exclusion of PCV1 antibody interference after PCV2 vaccination.
  
  
  RESULTS
  Virus-like particles (VLPs) of PCV2 based on the recombinant Cap protein were expressed in Escherichia coli. A competing ELISA was established by using the VLPs as coating antigen and a PCV2-specific monoclonal antibody as the competing antibody. The competing ELISA was compared with the results obtained by using an immunoperoxidase monolayer assay on 160 serum samples. The sensitivity and specificity of this competing ELISA were determined as 96.5 and 96.0 %, at 2 standard deviation from the mean or 91.8 and 100 % at 3 standard deviations from the mean. Next, a serological survey of 1297 vaccinated serum samples collected from commercial pig herds in Beijing, Hunan and Henan provinces in China was conducted. The results showed that 85.9 % of sera having positive PCV2 antibodies.
  
  
  CONCLUSIONS
  The competing ELISA we developed in this study was both sensitive and specific to PCV2 and was suitable for large-scale PCV2 antibody monitoring in exclusion of PCV1 antibody interference after PCV2 vaccination.
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Shuizhong
authors: S
authors: Han
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Yan
authors: Y
authors: Xiao
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Dingding
authors: D
authors: Zheng
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Yanli
authors: Y
authors: Gu
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Yajie
authors: Y
authors: Xuan
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Yudan
authors: Y
authors: Jin
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Wenqiang
authors: W
authors: Pang
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Yuxin
authors: Y
authors: Huang
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China.
authors: Xiangdong
authors: X
authors: Li
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China. dengbetter88@163.com.
authors: Junhua
authors: J
authors: Deng
authors: National Research Center for Veterinary Medicine, Luoyang, People's Republic of China. tiankg@263.net.|College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, People's Republic of China. tiankg@263.net.
authors: Kegong
authors: K
authors: Tian
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral / Q000097:blood* / Q000302:isolation & purification; D000956:Antigens, Viral; D036022:Capsid Proteins / Q000276:immunology; D018173:Circoviridae Infections / Q000097:blood / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000145:classification / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary*; D006358:Hot Temperature; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013047:Specific Pathogen-Free Organisms; D013552:Swine; D013553:Swine Diseases / Q000097:blood / Q000276:immunology / Q000821:virology*
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D036022:Capsid Proteins
keywords: Competitive ELISA; Porcine circovirus 2(PCV2); Recombinant cap protein; Virus-like particle