携带表达密码子优化的猪圆环病毒2型Cap蛋白真核质粒的重组沙门氏菌在猪体的免疫试验

he Cap protein was the major immune protein of PCV2, a pathogene which endangered the pig industry in the world. In this study, the recombinant plasmid pVAX-SynCap(m) expressing the codon-optimization Cap protein was transformed into the attenuated S.typhimurium strain SL3263 by electroporation, resulting in a strain SL-pVAX-SynCap(m). To detect the immunogenicity of the plasmids DNA pVAX-SynCap(m) and the recombinant bacteria SL-pVAX-SynCap(m)，the piglets were divided into five groups and vaccinated with the plasmids pVAX-SynCap(m) and pVAX，the bacteria SL-pVAX-SynCap(m) and S.typhimurium strain SL3263 and PBS. The results showed that the pigs vaccinated with the recombinant S.typhimurium and recombinant plasmid developed specific anti-PCV2 antibody by ELISA, but no neutralization antibody response. Meanwhile, no humoral responds could be detected in other control groups. After challenged with PCV2-SH, piglets inoculated with pVAX-SynCap(m) and SL-pVAX-SynCap(m) showed mild clinical signs, lower viremia and less gross lesion of lungs, comparing with those in other groups, and that of the SL-pVAX-SynCap(m)-vaccinated group were better than that of the pVAX-SynCap(m)-vaccinated group. These results indicated that SL-pVAX-SynCap(m) could markedly increase the immune responses and provide efficient protection against virulent PCV2 challenge in pigs. The study laid the foundation for the research of PCV2 oral vaccine which can completely prevent pig from PCV2 infection.