Isolation And Serotypic Characterization Of Human And Animal Rotaviruses

在这个项目中，我们根据来自人和动物的各种轮状病毒毒株的VP4和VP7中和特异性来确定抗原性关系。阐明轮状病毒的中和特异性对于更全面地了解轮状病毒流行病学和制定有效的疫苗接种策略非常重要。在5种全球重要的轮状病毒VP7 (G)血清型（G1-4和9）中，G9继续引起相当大的关注。这是因为九国集团病毒在人类社会中具有独特的自然历史和进化。血清型G9轮状病毒首先于1983年在美国从一名腹泻儿童身上分离出来，随后于1985年在日本分离出来。奇怪的是，G9轮状病毒被发现后不久，在这两个国家大约十年的时间里都没有被发现，然后在20世纪90年代中期在这两个国家重新出现。然而，意想不到的是，这些重新出现的G9菌株在遗传和分子上都与20世纪80年代分离出来的菌株不同。因此，重新出现的G9病毒的起源仍然是一个谜。序列分析表明，G9轮状病毒VP7基因属于至少三个系统发育谱系之一：谱系1（20世纪80年代在美国和日本分离的菌株），谱系2（1986年首次分离的菌株，迄今仅在印度分离）和谱系3（20世纪90年代中期出现或重新出现的菌株）。目前，3系G9病毒是全球最常检测到的G9毒株。在此之前，我们对猪G9轮状病毒进行了鉴定，并报道了猪G9病毒的VP7与当代人类谱系3病毒VP7s的血清典型和分子密切相关，并提出猪G9病毒VP7与人类谱系3病毒VP7s可能有共同的祖先，或者猪G9病毒VP7本身可能是当代人类谱系3病毒VP7s的祖先。在对1974 - 1991年华盛顿儿童医院收集的档案腹泻粪便样本进行轮状病毒毒株监测时，1980年收集的样本中检出3种G9病毒。我们成功地在细胞培养中培养了三种1980年G9病毒中的两种，然后对它们进行了生物学和分子表征。结果表明，这些病毒与谱系3 G9病毒血清典型关系密切，与谱系1和2 G9病毒有远亲关系。然而，这些G9病毒的VP7基因被发现(i)与2系G9病毒VP7基因有最密切的系统发育关系，（ii）与1系G9病毒VP7基因有密切的系统发育关系，以及（iii）与当代3系G9病毒VP7基因有较远的系统发育关系。此外，对来自GenBank数据库的26种G9病毒的VP7基因的密码子使用偏差分析证实了这一发现。这两种1980年的病毒是迄今为止在人类中分离到的最早的G9病毒，它们与谱系2 G9病毒可能代表了谱系1 G9病毒进化而来的祖先病毒。

In this project we determine the antigenic relationships based on VP4 and VP7 neutralization specificities of various rotavirus strains derived from humans and animals. The elucidation of the neutralization specificities of rotaviruses is important in order to achieve a more comprehensive understanding of rotavirus epidemiology and for formulation of an effective strategy for vaccination. Of 5 globally important VP7 (G) serotypes (G1-4 and 9) of rotaviruses, G9 continues to attract considerable attention. That is because the G9 viruses have a unique natural history and evolution in human communities. Serotype G9 rotavirus was isolated from a child with diarrhea first in the US in 1983 and subsequently in Japan in 1985. Curiously, soon after their detection, G9 rotaviruses were not detected for about a decade in both countries and then reemerged in both countries in the mid-1990s. Unexpectedly, however, such reemerged G9 strains were distinct genetically and molecularly from those isolated in the 1980s. Thus, the origin of the reemerged G9 viruses remains an enigma. Sequence analysis has demonstrated that the G9 rotavirus VP7 gene belongs to one of at least three phylogenetic lineages: lineage 1 (strains isolated in the 1980s in the US and Japan), lineage 2 (strains first isolated in 1986 and exclusively in India thus far) and lineage 3 (strains that emerged or reemerged in the mid-1990s). Currently, lineage 3 G9 viruses are the most frequently detected G9 strains globally. Previously, we characterized a porcine G9 rotavirus and reported that the VP7 of the porcine G9 virus was closely related serotypically and molecularly to contemporary human lineage 3 virus VP7s and suggested that the porcine G9 VP7 and human lineage 3 G9 virus VP7s may have a common ancestor or perhaps the porcine G9 virus VP7 itself may be a progenitor of contemporary lineage 3 human virus VP7s. During rotavirus strain surveillance of archival diarrheal stool samples collected at Childrens Hospital in Washington DC from 1974 to 1991, we detected 3 G9 viruses in samples collected in 1980. We successfully grew two of the three 1980 G9 viruses in cell cultures and then characterized them biologically and molecularly. These viruses were shown to be closely related serotypically to lineage 3 G9 viruses and distantly related to lineages 1 and 2 G9 viruses. However, the VP7 gene of these G9 viruses was found to have (i) a closest phylogenetic relationship to lineage 2 G9 virus VP7 gene, (ii) a close phylogenetic relationship to lineage 1 G9 virus VP7 genes, and (iii) a distant phylogenetic relationship to contemporary lineage 3 G9 virus VP7 genes. Moreover, codon usage bias analyses of the VP7 gene of a total of 26 G9 viruses (obtained from GenBank database) confirmed such findings. These two 1980 viruses, which are the earliest G9 viruses isolated in humans thus far, together with lineage 2 G9 virus may represent ancestral viruses from which lineage 1 G9 viruses evolved.