病毒学报

为了解北京地区人呼吸道合胞病毒(human respiratory syncytial virus,HRSV)的遗传变异和分子流行病学特征,首次对北京地区2003~2004年63株HRSV分离株进行了G基因3′末端的第2个高度变异区的序列测定,并进行了基因分型和遗传变异的分析。使用不同的型特异性引物对GPA-F1和GPB-F1分别扩增A、B血清型HRSVG基因3′末端核苷酸序列,特异性扩增产物和随后的序列测定结果均显示,北京地区2003~2004年63株HRSV毒株中,96.8%(61/63)为A血清型,3.2%(2/63)为B血清型,说明北京地区在2003~2004年间存在HRSV A、B血清型共循环,但以A血清型病毒为主。分别对北京流行的A和B血清型病毒进行了基因亲缘性关系分析,结果提示,61株北京A血清型分离株全部为GA2基因型;2株B血清型分离株为GB3基因型。由此看来,GA2基因型是北京地区2003~2004年的优势流行基因型。北京61株GA2分离株之间核苷酸和氨基酸同源性分别在87.8%~100%和77.9%~100%之间;2株B血清型分离株之间核苷酸和氨基酸同源性分别为94.7%和88.1%。这说明在2003年和2004年有很多个不同的GA2基因型HRSV毒株在北京地区共循环,北京地区的HRSV流行存在着许多由不同病毒株引起的传播链。B血清型分离株Beijing04-11于G基因3′末端含有一个60个碱基的重复序列,这是HRSV多聚酶易于重复复制限定序列的一个极端的例子,有可能是HRSV逃逸免疫压力而不断进化的一种方式。该研究首次对北京地区2003年和2004年流行的HRSV进行了基因分型和遗传变异的研究,对于了解北京HRSV流行株的基因特征具有重要意义,可以为北京乃至中国疫苗株的选择提供参考依据,从而指导HRSV的免疫预防控制。

To achieve the data of genetic diversity and molecular epidemiology of human respiratory syncytial virus(HRSV) in Beijing, nucleotide sequencing of the C-terminal region of the G protein gene was performed on 63 isolates obtained from Beijing Children's Hospital in year 2003 and 2004. The circulation pattern and genetic variability of both HRSV group A and B isolates circulating in Beijing were described. The results showed that 96.8% (61/63) Beijing HRSV isolates belonged to group A and 3.2% (2/63) belonged to group B in year 2003 and 2004 indicating that group A and B HRSV cocirculated in Beijing in year 2003 and 2004, predominating with group A HRSV. Phylogenetic analysis of partial G gene nucleotide sequences of Beijing 61 group A strains and 2 group B strains revealed that all 61 group A isolates clustered into one assigned genotype, GA2, 2 group B isolates clustered into one previously identified genotype GB3, which demonstrated that GA2 genotype was the predominating epidemic genotype in Beijing in year 2003 and 2004. The nucleotide sequence and amino acid homologies were 87.8%-100% and 77.9%-100% respectively among 61 Beijing group A isolates, and 94.7% and 88.1% respectively between two group B isolates, Beijing04-11 and Beijing04-66. There were several different HRSV GA2 genotype cocirculations causing HRSV epidemics of different HRSV transmission chains in Beijing in year 2003 and 2004. HRSV group B Beijing04-11 strain contained a 60bp-nucleotide duplication in the C-terminal region of the G-protein gene, which was similar with Ken/29/03 from Kenya and isolates from Buenos Aries in 1999. This was the special case for characteristics of HRSV polymerase prone to copy the duplicated region, possibly according to this way to help HRSV escape preexisting immunity. This is the first time study on the genetic diversity of human respiratory syncytial viruses isolated during the epidemic period from children in Beijing, China. These data provided a better understanding of the patterns of HRSV strains circulating in Beijing and the data of genetic diversity of epidemic HRSV is useful for development of diagnostic reagents and vaccine production.