辽宁省麻疹病毒流行株血凝蛋白特性分析

Characteristic analysis of hemagglutinin gene of measles virus recently circulating in Liaoning province of China

目的 比较辽宁省麻疹病毒流行株 (MVW)和目前使用的疫苗株血凝蛋白基因 (H)核苷酸 (nt)及氨基酸 (aa)序列差别 ,研究其生物学和免疫学特性及其基因型区别。方法 MVW流行株和长 - 47疫苗株的 H基因 1～ 180 0 nt及 1～ 6 0 0 aa序列分析 ;麻疹病人及疫苗免疫后的血清与MVW株和长 - 47疫苗株做中和抗体测定。结果 表明 MVW株基因型不同于其它国家以前报道的 MVW株基因型及我省现用的长 - 47疫苗株 ,有 18～ 2 8个 aa差异 ;还表明 MVW株具有重要生物学和免疫学活性的 aa位点 ,除 aa 2 38～ 2 40位点有一个 aa发生变异外 ,其余均与长 - 47疫苗株相同。另外麻疹病人恢复期血清和麻疹疫苗初次免疫儿童 (初免 )后 1个月的血清抗长 - 47及MVW毒株的中和抗体几何平均滴度 (GMT)差别无显著性 ,但是麻疹病人恢复期血清对这两毒株中和抗体滴度均明显高于初免儿童的中和抗体滴度。结论 辽宁省的 MVW株与长 - 47疫苗株基因型不同 ,说明 MVW株 nt存在变异 ;但是具有生物学和免疫学活性的 aa位点多数未发生改变 ,长 - 47疫苗株仍然能保护 MVW的感染。

Objective To compare difference of nt and aa of H gene between the measles virus strains(MVW) recently circulating and used vaccine strain (Chang 47) in Liaoning province of China, and to study biological and immunological characteristic and genotype of MVW and Chang 47. Methods The analysis of 1～1 800 nt and 1～600 aa about H gene of MVW and Chang 47 vaccine strain was performed. Neutralization test was performed against MVW and Chang 47 vaccine strain in the sera of measles cases and children vaccinated after 30 days. Results The genotype of the MVW was different from genotypes previously described in other countries and vaccine strain (Chang 47) used in Liaoning province. It also showed that 18～28 aa were distinct from aa of other genotype, but most of the important biological and immunological sites were not changing except the site at aa 240.Neutralization antibody titer GMT against MVW and Chang 47 strains were no significantly different in the sera of measles cases and the children vaccinated after 30 days, but antibody titers GMT of the measles cases sera against MVW or Chang 47 strain were much higher than children vaccinated. Conclusions There was nt variation in the MVW. Most of biological and immunological aa sites of the MVW and Chang 47 strains were the same and were not changing. Chang 47 vaccine may also protect from infection of the MVW.