戊型肝炎病毒(HEV)为线状单股正链RNA病毒，基因组全长约7．5kb(7．2～7．6kb)，编码2 400～2 533个氨基酸，由5’端非结构区(NS)和3’端结构区(S)组成，3’端带一个由150～200个腺苷酸残基组成的poly A尾巴。HEV基因组含3个开放读码框架(ORFs)，ORF1位于5’NS区，长5 079bp(第28～5107nt)，编码HEV复制相关蛋白，包括甲基转移酶、木瓜酶样的蛋白酶、解旋酶、RNA依赖性RNA聚合酶(RDRP)；ORF2从ORF1终止密码下游37个bp开始，长1 980bp(第5 147～ 7127nt)，编码660个氨基酸，主要包括信号肽和衣壳蛋白；ORF3位于ORF1、ORF2之间(第5 106～5 478nt)，与两者均有部分重叠，长369bp，编码一段123个氨基酸的多肽，功能不清。有学者认为ORF3编码的蛋白是一种与细胞骨架有关的磷蛋白，也有认为与转膜元件有关。本文仅就HEV抗原表位及ORF2抗原真核表达的研究进展简要综述如下。

一、HEV抗原表位的研究

(一)ORF1编码蛋白的抗原表位 Kaur等[1]在根据ORF1序列设计合成的系列多肽片段中，发现人类线状B细胞抗原表位存在于12个独立的多肽片段，其中有5个集中于第1207～1 446aa，该区域正处于RDRP内。RDRP内的抗原表位可能与非保护性反应有关；这些抗原也可能派生出附着于感染细胞膜表面的抗原位点，从而参与抗体依赖的抗病毒机制，如抗体依赖性细胞毒作用。……

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收稿日期：1999-08-11