麻疹病毒抗原性变异及免疫保护效果研究

目的 了解浙江省麻疹野毒株的抗原性变异状况以及麻疹疫苗的免疫保护效果。方法 采用麻疹国际标准株Edmonston株、疫苗株沪19l与近几年浙江省分离的麻疹野毒株(浙98-5和浙00-4)分别制备免疫血清，与各毒株进行交叉中和试验，并分别对不同来源的人群血清测定中和抗体滴度。结果 麻疹野毒株浙98-5与疫苗株沪川和Edm株的抗原比分别为3．0和2．6，浙00-4与上述两毒株的抗原比分别为7．30和5．65，其抗原性存在着明显的差异。麻疹疫苗初免儿童和麻疹急性期病人血清对麻疹野毒株的中和抗体几何平均滴度(GMT)分别为15．03和5．04，明显低于疫苗株沪19l，GMT分别为68．12和11．76。但健康人群血清对两毒株的中和抗体滴度无显性差异。结论 浙江省麻疹野毒株已出现较明显的抗原性变异，现行麻疹疫苗的免疫保护效果也受到一定影响。

Study on antigen variation of measles virus and immunoprotecive efficacy

Objective To study the antigen variation of wild-type measled virus (MV) that circulated in Zhejiang province and immunoprotecive efficacy of measles vaccine. Methods The anti-measles virus neutralization (NT) antibody titers in the immune serum of rats which were obtained in the earlier wild-type measles virus (Edmonston strain) and the vaccine strain and the two field strains (Zhe 98-5 and Zhe 00-4) isolated recently wae measured in cross neutralization test,meanwhile NT antibody titers in the serum of population which obtained from different sources were also measured respectively. Results Antigenic ratios of Zhe 98-5 strain to Hu 191 strain and Edm strain were 3.0 and 2.6 respectively,while those of Zhe 00-4 strain to the two standard strains described above were 7.30 and 5.65,suggesting an obvious mutual difference of antigenicity.The anti-wild type measles virus NT antibody geometric mean titer (GMT) in the serum of initial vaccines and naturally infected individuals were 15.03 and 5.04 respectively,which was obviously lower than anti-measles vaccine strain (GMT was 68.12 and 11.76 respectivety).But NT antibody titers to various strains in the serum of healthy population were with non-significant difference. Conclusion Antigenic variation of wild-type measles virus that circulated in Zhejiang presented obviouly and immunoprotecive effcacy of measles vaccine was partly influenced.