Identification of one critical amino acid that determines a conformational neutralizing epitope in the capsid protein of porcine circovirus type 2

BMC Microbiology

Research Article

Yan W Wei¹  Yue H Lu¹  Long J Guo¹  Li P Huang¹  Chang M Liu¹ 

[1] Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, 427 Maduan Street, 150001, Harbin, Nangang District, China;

关键词: Capsid Protein;    Neutralize Activity;    Conformational Epitope;    Capture ELISA;    Critical Amino Acid;   

DOI  :  10.1186/1471-2180-11-188

 received in 2011-05-22, accepted in 2011-08-22,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundPorcine circovirus type 2 (PCV2) is associated with post-weaning multisystemic wasting syndrome (PMWS) in pigs. Currently, there is considerable interest in the immunology of PCV2; in particular, the immunological properties of the capsid protein. This protein is involved in PCV2 immunogenicity and is a potential target for vaccine development. In this study, we identified one critical amino acid that determines a conformational neutralizing epitope in the capsid protein of PCV2.ResultsOne monoclonal antibody (mAb; 8E4), against the capsid protein of PCV2, was generated and characterized in this study. 8E4 reacted with the genotype PCV2a (CL, LG and JF2) strains but not PCV2b (YJ, SH and JF) strains by an immunoperoxidase monolayer assay (IPMA) and a capture ELISA. Furthermore, the mAb had the capacity to neutralize PCV2a (CL, LG and JF2) strains but not PCV2b (YJ, SH and JF) strains. One critical amino acid that determined a conformational neutralizing epitope was identified using mAb 8E4 and PCV2 infectious clone technique. Amino acid residues 47-72 in the capsid protein of PCV2a/CL were replaced with the corresponding region of PCV2b/YJ, and the reactivity of mAb 8E4 was lost. Further experiments demonstrated that one amino acid substitution, the alanine for arginine at position 59 (A59R) in the capsid protein of PCV2a (CL, LG and JF2) strains, inhibited completely the immunoreactivity of three PCV2a strains with mAb 8E4.ConclusionsIt is concluded that the alanine at position 59 in the capsid protein of PCV2a (CL, LG and JF2) strains is a critical amino acid, which determines one neutralizing epitope of PCV2a (CL, LG and JF2) strains. This study provides valuable information for further in-depth mapping of the conformational neutralizing epitope, understanding antigenic difference among PCV2 strains, and development of a useful vaccine for control of PCV2-associated disease.

【 授权许可】

Unknown   
© Huang et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.