采用分子克隆技术，构建E7变异株重组质粒[pcDNA3.1-(by)E7]和E7标准株重组质粒[pcDNA3.1-(ys)- E7]，并将两种质粒分别皮下免疫Balb/c小鼠，免疫后于不同时间提取小鼠血清和制备脾淋巴细胞悬液，分别用ELISA法和MTT比色法检测特异性抗体和特异性淋巴细胞增殖反应。基因免疫后，ELISA法显示，HPV16 E7变异株和标准株均能诱导特异性抗E7抗体；MTT比色法显示，E7标准株免疫组脾淋巴细胞在体外受到变异株E7蛋白的再次刺激后出现特异性淋巴细胞增殖反应，变异株E7免疫组脾淋巴细胞经过同样处理后，出现非特异性淋巴细胞增殖反应。结果表明HPV16 E7变异株能诱导特异性体液免疫应答而不能诱导特异性细胞免疫应答，HPV16 E7变异株无论在结构还是免疫原性上均与标准株有差异。由此推测，HPV16E7变异可能导致其逃逸机体自然感染或疫苗诱导的免疫应答。用基因免疫方法研究E7变异株免疫原性也为其它不能或难以进行体外培养的病毒变异研究提供借鉴。

The HPV E7 variant shares the same coding sequence with the wild type E7 except that the 43rd cordon was mutated from CAA to TAA. The recombined plasmid pcDNA3.1-(by) E7 DNA and pcDNA3.1-(ys)- E7 DNA, were constructed by molecular clone technology, and then injected into mice intradermally respectively. The serum and the spleen lymphocyte suspension of the mice were isolated respectively at different time. The specific antibody was detected by ELISA and the lymphocyte proliferative response was detected by MTT method. After gene immune, the result of ELISA showed both the HPV16 (ys) E7 and HPV16 (by) E7 could induce specific antibody. The result of MTT method showed in comparison to HPV16 (ys) E7, no specific lymphoproliferation after E7 protein restimulation in vitro was detected in HPV16 (by) E7 group. The results suggested that the variant E7 protein could induce host humoral immune response, but could not elicit special cellular-immune to it, which indicated that HPV16 E7 variant was different from wild type HPV16 E7 in both structure and immunuogenicity, perhaps resulting in escaping the nature infection and the response induced by vaccines, leading to persistent infection. Furthermore, this experiment offered reference for other studies on virus variant which can’t be cultivated in vitro.