猪圆环病毒Ⅱ型广东分离株全基因组的克隆和序列分析

分离了9株猪圆环病毒Ⅱ型（PCV2）广东地方分离株，并进行了全基因组序列测定；对这9株PCV2广东分离毒株的ORF1和ORF2基因的序列分析表明ORF2的变异程度要比ORF1的变异程度大；对PCV2衣壳蛋白的氨基酸序列同源性比较发现了PCV2毒株间存在1个氨基酸变异程度较大的区域和2个氨基酸变异程度较小的区域，其中前两个区域与两个主要的免疫反应区域相对应；将这9个毒株的全基因组序列与GenBank上收录的18个PCV2毒株的全基因组序列基因进化树分析表明，这9个PCV2广东分离株彼此之间及与国内PCV2分离株、欧洲株之间更接近，而与韩国、中国台湾、日本和美洲毒株之间则稍远，因而在选PCV2疫苗免疫时，建议尽量使用国内生产的疫苗或自制组织灭活疫苗进行免疫。

Cloning and sequence analysis of porcine circovirus type 2 strains from Guangdong province

Nine porcine circovirus type 2(PCV2) isolates from Guangdong province were sequenced. Sequence analysis of the ORF1 and ORF2 genes of the nine strains revealed that the extent of ORF2 nuclear nucleotide variation was greater than that of ORF1. The amino acid sequences alignment of the PCV2 capside protein identified one major heterogeneous region and two minor heterogeneous regions, the former two regions of which correspond with dominant immunoreative areas; sequence analysis of the complete genomes of the nine PCV2 isolates with that of eighteen PCV2 sequences published in GenBank indicated that the nine PCV2 strains are closely related to each other and to other PCV2 strains from China and Europe, but not as well to those from Kerea, Taiwan province, Japan and North American. Thus, we had better use the vaccines from China, or the vaccine produced by the pathological tissues collected from the PCV2-affected farm.