Capsid proteins from PCV2a genotype confer greater protection against a PCV2b strain than those from PCV2b genotype in pigs: evidence for PCV2b strains becoming more predominant than PCV2a strains from 2000 to 2010s
Capsid proteins from PCV2a genotype confer greater protection against a PCV2b strain than those from PCV2b genotype in pigs: evidence for PCV2b strains becoming more predominant than PCV2a strains from 2000 to 2010s
复制标题
在猪中，PCV2a 基因型的衣壳蛋白比 PCV2b 基因型的衣壳蛋白对 PCV2b 病毒株具有更强的保护作用：有证据表明，从 2000 年到 2010 年代，PCV2b 病毒株比 PCV2a 病毒株更占优势
DOI：
10.1007/s00253-016-7459-y
复制
发表时间：
2016-07-01
影响因子：
5
通讯作者：
Liu, Changming
中科院分区：
文献类型：
--
作者：
Huang, Liping;Wang, Yiping;Liu, Changming
猪圆环病毒2型（PCV 2）有两种主要的基因型，PCV 2a和PCV 2b。直到2000年，PCV 2a在全球猪群中占主导地位，而PCV 2b从2003年开始占主导地位。本研究的目的是分析两种PCV 2a和两种PCV 2b衣壳蛋白（Caps）在用突变型PCV 2b/YJ（mPCV 2b/YJ）毒株攻击的猪中赋予的免疫保护作用。与PCV 2b/JF-Cap和mPCV 2b/YJ-Cap相比，用PCV 2a/LG-Cap和PCV 2a/CL-Cap免疫的猪引起显著更高水平的PCV 2特异性抗体和中和抗体。mPCV 2b/YJ攻毒后，在PCV 2a/LG-Cap和PCV 2a/CL-Cap组中未检测到病毒血症，而在PCV 2b/JF-Cap和mPCV 2b/YJ-Cap组中分别有20%和40%的猪发现病毒血症。PCV 2b/JF-Cap和mPCV 2b/YJ-Cap组猪腹股沟淋巴结中的病毒载量显著高于PCV 2a/LG-Cap和PCV 2a/CL-Cap组，但显著低于攻毒对照组。此外，在来自商业疫苗组以及PCV 2a/LG-Cap和PCV 2a/CL-Cap组的猪的腹股沟淋巴结中未检测到PCV 2抗原，但在攻毒对照（100%，5/5）、PCV 2b/JF-Cap（20%，1/5）和mPCV 2b/YJ-Cap（20%，1/5）组中发现了PCV 2抗原。这些结果表明，mPCV 2b/YJ-Cap和PCV 2b/JF-Cap的免疫原性低于PCV 2a/LG-Cap和PCV 2a/CL-Cap。我们推测，从PCV 2a到PCV 2b的基因型转变可能是大多数PCV 2a毒株比大多数PCV 2b毒株更具免疫原性的结果。这些结果为为什么PCV 2b毒株比PCV 2a毒株更容易引起流行提供了可能的解释。提示PCV 2的致病性可能与其免疫原性有一定的关系。
Two major porcine circovirus type 2 (PCV2) genotypes, PCV2a and PCV2b, are recognized. PCV2a was predominant in the global pig population until 2000 while PCV2b became predominant from 2003 onward. 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 (mPCV2b/YJ) strain. 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 mPCV2b/YJ-Cap. Following a mPCV2b/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 mPCV2b/YJ-Cap groups, respectively. Viral loads in the inguinal lymph nodes of pigs from the PCV2b/JF-Cap and mPCV2b/YJ-Cap groups were significantly higher than those in the PCV2a/LG-Cap and PCV2a/CL-Cap groups, but significantly lower than those of the challenge control group. Furthermore, PCV2 antigens were not detected in the inguinal lymph nodes of pigs from commercial vaccine groups, as well as 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 mPCV2b/YJ-Cap (20 %, 1/5) groups. These findings suggest that mPCV2b/YJ-Cap and PCV2b/JF-Cap were less immunogenic than PCV2a/LG-Cap and PCV2a/CL-Cap. We 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. These results provide a possible explanation for why PCV2b strains are more likely to cause epidemics than PCV2a strains. It tells us that PCV2 pathogenesis may be associated with its immunogenicity to some extent.