The effect of RSV genotypes on the development of asthma after RSV lower respiratory tract infection

根据1980-2002年在日本两个城市札幌和东京20个季节分离的109株呼吸道合胞病毒（RSV）野毒株，研究了日本RSV的循环模式和遗传进化。采用RT-PCR方法扩增大糖蛋白（G）基因第二高变区，产物直接测序。将核苷酸序列与先前鉴定的RSV基因型的代表进行比较。日本A组和B组分离株分别聚为5种和4种基因型。另外还鉴定了一个A组和一个B组基因型，这些基因型不能归属于以前的基因型。虽然不同的基因型在不同的季节通常是共同循环的，但来自两个群落的近季节的菌株通常位于同一分支。此外，具有先前定义的基因型的菌株通常与西方国家的每个参考菌株同时分离。在札幌新鉴定了几个G蛋白氨基酸长度延长1-20个的突变型B群菌株。这些结果表明，日本RSV毒株经历了地理和时间聚类，同时参与全球背景下的RSV遗传进化。此外，日本株，特别是B组，可能在每个群体中单独进化，有时改变G蛋白的长度。接下来，研究RSV亚群/基因型与RSV下呼吸道感染的预后（即反复喘息或支气管哮喘）之间的关系。然而，特定亚组/基因型与这些疾病之间没有明显的关系。

The circulation pattern and genetic evolution of respiratory syncytial virus (RSV) in Japan were examined based on 109 RSV field strains isolated over 20 seasons (1980-2002) in two cities, Sapporo and Tokyo. The second hypervariable region of the large glycoprotein (G) gene was amplified by RT-PCR and the products sequenced directly. The nucleotide sequences were compared to those representatives of RSV genotypes identified previously. Japanese group A and B isolates clustered into five and four genotypes defined previously, respectively. Another one group A and one group B genotypes, which could not be assigned to previous genotypes, were also identified. Although different genotypes usually co-circulated in each season, the isolates in proximate seasons from two communities were usually located in the same branches. Moreover, the strains with genotypes defined previously were usually isolated at the same time as each reference strain of Western countries. Several mutant group B strains with 1-20 longer amino acid G proteins were newly identified in Sapporo. These findings suggest that Japanese RSV strains underwent geographical and also temporal clustering while participating in RSV genetic evolution in a global setting. In addition, Japanese strains, especially group B, might have evolved individually in each community, sometimes changing the length of the G protein.Next, the relationship between RSV subgroup / genotype and the prognosis of RSV lower respiratory tract infection, that is recurrent wheezing or bronchial asthma were investigated. However, no apparent relationship of particular subgroup / genotype and these diseases.