Porcine circovirus type 2 (PCV2) is an economically important cause of post-weaning multisystemic wasting syndrome (PMWS) in weanling piglets. Current commercial vaccines against PCV2 are highly effective. Yet, a recurring emergence of new genotypes in vaccinated herds necessitates a better understanding of protective immunity. The study objectives were to identify previously unrecognized decoy epitopes in the PCV2 capsid and test the hypothesis that early antibody responses would map to decoy epitopes and vice versa. Using a peptide library spanning the PCV2a capsid and weekly sera collections from PCV2a infected animals, three major immunodominant regions mapping the early responses to decoy epitopes were identified. Regions with potential decoy activity were mapped using peptide blocking fluorescent focus inhibition assays to residues 55 YTVKATTVRTPSWAVDMM 72, 106 WPCSPITQGDRGVGSTAV 123 and 124 ILDDNFVTKATALTYDPY 141. Post-vaccination responses largely recognized these same three identified regions and dominated the antibody responses to PCV2 in both infection and vaccination.

中文翻译：

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早期抗体反应映射到非保护性PCV2衣壳蛋白表位。

猪圆环病毒2型（PCV2）是断奶仔猪断奶后多系统消耗综合症（PMWS）的重要经济原因。当前针对PCV2的商业疫苗是高度有效的。然而，在疫苗接种的牛群中新基因型的反复出现需要更好地了解保护性免疫。该研究的目的是鉴定PCV2衣壳中先前无法识别的诱饵表位，并检验早期抗体反应会映射到诱饵表位，反之亦然的假说。使用横跨PCV2a衣壳的肽库和每周感染PCV2a的动物的血清，鉴定了三个主要的免疫优势区域，这些区域映射了对诱饵表位的早期反应。