Genetic analysis of measles viruses isolated in Japan and mechanism of transmission-role of antibodies induced by vaccination

测定了日本20世纪80年代以来分离的麻疹病毒H和N基因的核苷酸序列，并与数据库中的序列进行了比较。通过检测突变的累积和基因的发育，推测了每种病毒的来源，并讨论了接种疫苗获得的抗体对突变累积速度的影响。D3型病毒：D3型病毒在20世纪80年代末和90年代初流行，被D5型病毒取代，1997年再次出现。重新出现的D3病毒起源于日本的美国/94类毒株，并在日本变异成两个谱系。D5病毒：21世纪初的D5病毒被认为是90年代初D5病毒的祖先，最有可能的祖先是Palau.BLA/93类病毒。2007年，麻疹病毒感染在东京爆发，现在正在日本各地蔓延。此次疫情中分离到的病毒与2000年代初的D5型病毒属于不同的谱系，与MVI/Queensland/AU/37.03属于同一谱系。H1型病毒：H1型病毒自1999年以来一直在日本分离。从日本分离到的H1型病毒可分为两组，有可能是两种不同基因序列的H1型病毒入侵日本。我们不能证实从接种疫苗的患者身上分离出的病毒的突变增加。麻疹病毒的多样性：从患者身上提取的一种麻疹病毒株被发现不是单一的基因，而是一个混合的群体。

Nucleotide sequences of the H and N genes of measles viruses isolated in Japan since 1980s were determined and compared with those obtained from databases. By examining accumulation of the mutations and genetic development of the genes, the origin of each virus was assumed and the affect of antibodies acquired by vaccination on the rate of accumulation of the mutations was discussed.Type D3 virus : Type D3 viruses were prevailing in the late 1980s and the early 1990s, which were replaced by Type D5 viruses and emerged again in 1997. Re-emerging D3 viruses originated from the Guam.USA/94 like strain and mutated into two lineages in Japan.Type D5 virus : Type D5 viruses in the early 2000s were supposed to be the progenitor of type D5 viruses in the early 1990s and the most probable ancestor was the Palau.BLA/93 like virus. In 2007, the measles virus infection burst around Tokyo and is now spreading all over Japan. The isolated viruses from the epidemic belong to the different lineage of type D5 from that of type D5 viruses in the early 2000s, to the same lineage with MVi/Queensland.AU/37.03.Type H1 virus : Type H1 viruses have been isolated in Japan since 1999. Type H1 viruses isolated in Japan could be divided into two groups and there is a possibility that two kinds of type H1 virus possessing different gene sequences invaded into Japan.Isolates from vaccinated patients : H and N genes of the viruses from the vaccinated patients were compared with those of isolates from the same epidemic. We could not confirm the increased accumulation of mutations with the viruses isolated from vaccinated patients.Diversity of measles virus : A strain of measles virus derived from a patient revealed not to be genetically single but to be a mixed population.