Capsid Proteins from PCV2a Genotype Confer Greater Protection against a PCV2b Strain than those from PCV2b Genotype in Pigs:Infers the Reason of PCV2b Strains Becoming More Predominant than PCV2a Strains
作者单位：Harbin Veterinary Research Institute Chinese Academy of Agricultural Sciences
会议名称：《第十届全国免疫学学术大会》
会议日期：2015年
学科分类：090601[农学-基础兽医学] 09[农学] 0906[农学-兽医学]
关 键 词：Porcine circovirus type 2 PCV2a and PCV2b genotypes Immunogenicity
摘 要：Background:Two major porcine circovirus type 2(PCV2)genotypes,PCV2a and PCV2b,are ***2a was predominant in the global pig population until 2000 while PCV2b became predominant from 2003 ***:The aim of this study was to analyze the immune protection conferred by two PCV2a and two PCV2b capsid proteins(Caps)in pigs challenged with a mutant PCV2b/YJ(m PCV2b/YJ)***:In this study,PCV2a/LG-Cap,PCV2a/CL-Cap,PCV2b/JF-Cap,and mutant PCV2b/YJ(m PCV2b/YJ)-Cap were expressed in a baculovirus system,and immune protection was investigated in pigs challenged with the m PCV2b/YJ ***:Pigs vaccinated with PCV2a/LG-Cap and PCV2a/CL-Cap elicited significantly higher levels of PCV2-specific antibodies and neutralizing antibodies compared with PCV2b/JF-Cap and m PCV2b/*** a m PCV2b/YJ challenge,no viremia was detected in the PCV2a/LG-Cap and PCV2a/CL-Cap groups,while viremias were found in 20%and 40%of the pigs in the PCV2b/JF-Cap and m PCV2b/YJ-Cap groups,*** loads in the inguinal lymph nodes of pigs from the PCV2b/JF-Cap and m PCV2b/YJ-Cap groups were significantly higher than those in the PCV2a/LG-Cap and PCV2a/CL-Cap groups,but significantly lower than that of the challenge control ***,PCV2antigens were not detected in the inguinal lymph nodes of pigs from commercial vaccine groups,the PCV2a/LG-Cap and PCV2a/CL-Cap groups,but were found in the challenge control(100%,5/5),PCV2b/JF-Cap(20%,1/5),and m PCV2b/YJ-Cap(20%,1/5)***:These findings suggest that m PCV2b/YJ-Cap and PCV2b/JF-Cap were less immunogenic than PCV2a/LG-Cap and PCV2a/CL *** speculate that a genotypic shift from PCV2a to PCV2b might be the result of the majority of PCV2a strains being more immunogenic than the majority of PCV2b strains.