Study on Human Rotavirus Antigen by Use of Genetic Reassortants

从MA104细胞与人轮状病毒Wa株(血清1-亚组II)和HN126株(血清2-亚组I)混合感染获得的病毒克隆中，以血清2型或血清1型特异性抗血清为选择压力，从获得的病毒克隆中筛选出2株重组病毒。血清型特异性抗血清中和试验和亚群特异性单抗酶联免疫吸附试验表明，它们是临床标本中尚未见过的具有独特抗原成分的重组毒株，即血清1-亚群I型(C116株)和血清2型-亚群II型(C15株)。病毒RNA的聚丙烯酰胺凝胶电泳法分析表明，编码主要亚型蛋白VP6的C116的RNA片段6来自HN126亲本，编码次要和主要血清型特异性中和蛋白VP3和VP7的片段4和9分别来自Wa亲本。与之相反，重组子C15含有源自Wa亲本的6个片段(编码亚群蛋白VP6)。关于编码中和蛋白的RNA，C15在接收来自WA亲本的编码VP3的片段4的同时，包含来自HN126亲本的编码VP7的基因组片段(片段8或9)。尽管这一血清型花叶病毒株的基因组组成表明它是一种2型病毒，因为它与2型抗血清(可能是由于HN126来源的主要中和蛋白VP7)具有较好的中和反应能力，但令人惊讶的是，C15的抗血清对1型和2型病毒株都有同样的中和作用。这一结果表明，基因重组毒株作为轮状病毒疫苗生产的有希望的候选株具有很大的实用价值。

Two reassortant viruses were selected from viral clones obtained by a mixed infection of MA104 cells with human rotavirus strains Wa (serotype 1-subgroup II) and HN126 (serotype 2-subgroup I),using either serotype 2 or serotype 1-specific antisera as selective pressure. Neutralization test with serotype-specific antisera and enzyme-linked immunosorbent assay with subgroup-specific monoclonal antibodies revealed that they were reassortant strains having unique antigenic compositions not yet encountered in clinical specimens, i.e. serotype 1-subgroup I (C116 strain) and serotype 2-subgroup II (C15 strain).Analysis by polyacrylamide gel electrophoresis of viral RNA concluded that while RNA segment 6 of C116 coding for the major subgrouping protein VP6 was derived from HN126 parent, its segments 4 and 9 coding for the minor and major serotype-specific neutralizing proteins VP3 and VP7, respectively were derived from Wa parent. In contrast, the reassortant C15 was found to contain segment 6 (encoding subgrouping protein VP6) originated from Wa parent. Regarding RNAs encoding neutralizing proteins, C15, while receiving segment 4 coding for VP3 from Wa parent, contained the genome segment coding for VP7 (either segment 8 or 9) from HN126 parent. Although this serotypic mosaic strain in terms of its genomic constitution was shown to be a serotype 2 virus on the basis of its preferential reactivity in neutralization reaction with serotype 2 antiserum (possibly because of the major neutralizing protein VP7 of HN126 origin), surprisingly the antiserum against C15 equally neutralized both serotype 1 and serotype 2 strains. This result indicates the great utility of genetically reassorted strains as promissing candidates for rotavirus vaccine production.