Liu Jiankui, Zhou Xia, Zhai Junqiong, Li Bing, Wei Chunhua, Dai Ailing, Yang Xiaoyan, Luo Manlin
College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
College of Life Sciences of Longyan University, Longyan, 364012, Fujian, China.
Arch Virol. 2017 Sep;162(9):2603-2615. doi: 10.1007/s00705-017-3393-2. Epub 2017 May 12.
The objective of this study was to assess the genetic diversity of porcine reproductive and respiratory syndrome virus circulating in Fujian province (southeastern China). Based on 53 ORF5 nucleotide sequences collected from nine sites, both highly pathogenic (sublineage 8.7) and lineage 1 strains were circulating in Fujian in 2009-2014 along with lineages 3 and 5.1. Notably, the lineage 1 strains were closely related to the NADC30 strain circulating in North America and were the predominant strains in 2014. In addition, we found that nonstructural protein 2 (NSP2) was the most variable nonstructural protein in Fujian isolates, with a 36-amino-acid (aa) insertion and seven different deletions detected in the 53 sequences examined. Similarly, analysis of GP5 amino acid sequences showed that the isolates were highly variable in primary neutralizing epitopes. Interesting, FJ3.2 and FJ7-2 strains have the mutation N44K, but they exhibited high replication and high titers in MARC-145 and PAM cells. The complete genome sequences determined for 12 type 2 isolates were 82.1-99.3% identical and were 15,016-15,407 nucleotides (nt), in length excluding the poly(A) tail. The strains also shared 88.2-99.4% identity with strain VR2332 (the prototype North American strain), 83.4-99.2% identity with strain JXA1 (the prototype high-pathogenicity Chinese strain), 88.2-97.1% identity with strain CH-1a (the prototype classical Chinese strain), and 82.9-97.1% identity with strain NADC30 (the prototype NADC30-like strain). Strikingly, phylogenetic and molecular evolutionary analyses indicated that strain FJW05 is a spontaneous recombinant between a circulating lineage 1 virus and the vaccine strain JXA1-R, which is derived from the highly pathogenic strain JXA-1. Collectively, the data highlight the epidemiology of porcine reproductive and respiratory syndrome in Fujian and may aid in selecting a suitable vaccine for use on pig farms.
本研究旨在评估在中国东南部福建省流行的猪繁殖与呼吸综合征病毒的遗传多样性。基于从9个地点收集的53个开放阅读框5（ORF5）核苷酸序列，2009 - 2014年期间，高致病性毒株（亚谱系8.7）和谱系1毒株与谱系3和5.1毒株一起在福建流行。值得注意的是，谱系1毒株与在北美流行的NADC30毒株密切相关，并且是2014年的主要毒株。此外，我们发现非结构蛋白2（NSP2）是福建分离株中最具变异性的非结构蛋白，在所检测的53个序列中检测到一个36个氨基酸（aa）的插入和7种不同的缺失。同样，对糖蛋白5（GP5）氨基酸序列的分析表明，分离株在主要中和表位上具有高度变异性。有趣的是，FJ3.2和FJ7 - 2毒株有N44K突变，但它们在MARC - 145和猪肺泡巨噬细胞（PAM）细胞中表现出高复制率和高滴度。测定的12个2型分离株的全基因组序列长度为15,016 - 15,407个核苷酸（nt）（不包括poly(A)尾），序列一致性为82.1 - 99.3%。这些毒株与VR2332毒株（北美原型毒株）的序列一致性为88.2 - 99.4%，与JXA1毒株（中国高致病性原型毒株）的序列一致性为83.4 - 99.2%，与CH - 1a毒株（中国经典原型毒株）的序列一致性为88.2 - 97.1%，与NADC30毒株（NADC30样原型毒株）的序列一致性为82.9 - 97.1%。引人注目的是，系统发育和分子进化分析表明，FJW05毒株是一种循环谱系1病毒与疫苗毒株JXA1 - R之间的自发重组体，JXA1 - R源自高致病性毒株JXA - 1。总体而言，这些数据突出了福建猪繁殖与呼吸综合征的流行病学情况，并可能有助于为猪场选择合适的疫苗。
