HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Shen, H.-G. Articles by Gong, L.-Y. PubMed PubMed Citation Articles by Shen, H.-G. Articles by Gong, L.-Y. Agricola Articles by Shen, H.-G. Articles by Gong, L.-Y.

Protective immunity against porcine circovirus 2 by vaccination with ORF2-based DNA and subunit vaccines in mice

¹ Laboratory of Virology and Immunology, Institute of Preventive Veterinary Medicine, Zhejiang University, Hangzhou 310029, PR China
² State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou 310003, PR China

Correspondence
Ji-Yong Zhou
jyzhou{at}zju.edu.cn

The protective immune response against porcine circovirus 2 (PCV2) infection in mice was characterized using flow cytometric analysis (FCM), assays of antibody (of different IgG isotypes) and viraemia, and histopathological examination. An open reading frame 2 plasmid (pORF2) and the capsid protein (Cap) of PCV2 were used as DNA and subunit vaccines, respectively. In FCM analysis, although pORF2 and Cap alone showed comparable efficacy in eliciting lymphoproliferative responses and Cap-specific CD4⁺ T cells, pORF2 was superior to the Cap protein in triggering CD8⁺ T cells. A virus neutralization assay showed that pORF2 evoked stronger recall virus-neutralizing (VN) antibody responses than the Cap protein on PCV2 challenge. Correspondingly, VN antibody kinetics coincided with those of Cap-specific IgG2a, but not with the kinetics of IgG and IgG1. Following virus challenge, real-time PCR and histopathological analysis confirmed that only low viral DNA loads and mild microscopic lesions appeared in pORF2-immunized mice. These findings indicate that CD8⁺ T cells and VN antibody responses correlating mainly with Cap-specific IgG2a play crucial roles in protecting against PCV2 infection, and that the protective immunity induced by the pORF2 plasmid is superior to that induced by the PCV2 Cap protein.