Studies on the significance of antigenic variation in influenza C epidemiology

1.对1982-1983年在近畿地区分离的三种C型流感病毒株进行的抗原性和遗传分析表明，它们彼此非常相似，但与1982年之前在日本分离的任何病毒株都不同。将这些毒株的HE基因序列与先前发表的毒株的HE基因序列进行比较，发现Kinki分离株与1980年在美国分离的病毒（密西西比/1/80）具有高度同源性。用多克隆血清进行血清学试验，可将来自Kinki和密西西比的分离株与以前的分离株区分开来。这些观察结果表明，一种与密西西比/1/80密切相关的C型流感变异株在1982-1983年在近畿迅速传播，可能是因为这种输入病毒的抗原性与以前流行的病毒有很大不同。还对1985-1989年在日本分离的8株丙型流感病毒株进行了抗原性和遗传分析。两个1985年分离株中的一个与密西西比/1/80相似，而另一个与之前分离的任何菌株都不相似。然而，1986年以后分离的六种毒株都与1981年在爱知县分离的病毒（爱知/1/81）相似，这增加了在1986-1989年爱知/1/81样变体可能比任何其他共存毒株具有流行病学优势的可能性。分离丙型流感病毒的技术一直局限于羊膜接种含胚鸡蛋，这对于常规使用来说太费力了。因此，我们试图开发一种用于分离病毒的组织培养方法，并发现人黑色素瘤细胞系（HMV- II）可用于此目的。

1. Antigenic and genetic analyses of three influenza C strains, isolated in the Kinki district in 1982-1983, showed that they were very similar to one another but dissimilar to any of the strains isolated in Japan before 1982. A comparison of the HE gene-sequences of these strains with those of the previously published ones revealed that the Kinki isolates had a high degree of homology with the virus isolated in 1980 in the United States (Mississippi/1/80). The isolates from Kinki and Mississippi could be distinguished from the previous isolates in serological tests with polyclonal sera. These observations suggest that an influenza C variant closely related to Mississippi/1/80 has spread rapidly in Kinki in 1982-1983 presumably because this imported virus was largely different in antigenicity from the previously prevalent ones.2. Antigenic and genetic analyses of eight influenia C strains isolated in Japan in 1985-1989 were also performed. One of the two 1985 isolates was similar to Mississippi/1/80 whereas the other was dissimilar to any of the previously isolated strains. Six strains isolated after 1986, however, all resembled the virus isolated in 1981 in the Aichi prefecture (Aichi/1/81), raising the possibility that in 1986-1989 the Aichi/l/81-like variant may have possessed an epidemiological advantage over any of the other coexisting strains.3. The technique for isolation of influenza C virus has been confined to the amniotic inoculation of embryonated hen's eggs that is too laborious for routine use. Therefore we attempted to develop a tissue culture method for isolation of the virus and found that a human melanoma cell line (HMV- II) is useful for this purpose.