Brown E A, Jansen R W, Lemon S M
Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill 27599-7030.
J Virol. 1989 Nov;63(11):4932-7. doi: 10.1128/JVI.63.11.4932-4937.1989.
PA21, a strain of hepatitis A virus (HAV) recovered from a naturally infected captive owl monkey, is indistinguishable from human HAV in polyclonal radioimmunoassays and cross-neutralization studies. However, cDNA-RNA hybridization has suggested a significant difference at the genomic level between PA21 and a reference human virus, HM175. Further characterization of this unique HAV was undertaken in an effort to determine the extent of genetic divergence from human HAV and its relation to the conserved antigenic structure of the virus. The close similarity between PA21 and HM175 antigens was confirmed with an extended panel of 18 neutralizing murine monoclonal antibodies: a reproducible difference in binding to the two viruses was detected with only one antibody (B5-B3). The nucleotide sequence of the P1 region of the PA21 genome had only 83.2% identity with HM175 virus, a difference approximately twice as great as that found between any two human strains. Most nucleotide changes were in third base positions, and the amino acid sequences of the capsid proteins were largely conserved. Amino acid replacements were clustered in the carboxy terminus of VP1 and the amino-terminal regions of VP2 and VP1. These data indicate that PA21 virus represents a unique genotype of HAV and suggest the existence of an ecologically isolated niche for HAV among feral owl monkeys.
PA21是从一只自然感染的圈养夜猴体内分离出的一株甲型肝炎病毒（HAV），在多克隆放射免疫分析和交叉中和研究中，它与人类HAV无法区分。然而，cDNA-RNA杂交表明，PA21与一种参考人类病毒HM175在基因组水平上存在显著差异。为了确定该独特HAV与人类HAV的遗传差异程度及其与病毒保守抗原结构的关系，对其进行了进一步的特性分析。用一组扩展的18种中和鼠单克隆抗体证实了PA21与HM175抗原之间的高度相似性：仅用一种抗体（B5-B3）就检测到了两种病毒结合的可重复性差异。PA21基因组P1区域的核苷酸序列与HM175病毒的同一性仅为83.2%，这一差异大约是任何两个人类毒株之间差异的两倍。大多数核苷酸变化发生在第三位碱基，衣壳蛋白的氨基酸序列在很大程度上是保守的。氨基酸替换集中在VP1的羧基末端以及VP2和VP1的氨基末端区域。这些数据表明，PA21病毒代表了一种独特的HAV基因型，并提示在野生夜猴中存在一个HAV的生态隔离生态位。
