一直以来人们认为麻疹病毒抗原性稳定，但近年来麻疹疫苗的广泛使用可能使麻疹病毒的变异加快，从而可能影响疫苗的免疫保护效果。国外有一些研究表明有些麻疹野病毒的抗原位点发生了变异；疫苗免疫后血清中和疫苗株的滴度高于中和现流行野毒株的。我国在此方面尚处于起步阶段。非常有必要对我国流行麻疹病毒的分子进化和抗原变异规律进行系统的研究；通过三维空间晶体结构模型，动态研究抗原氨基酸变异可能引起的蛋白结构和功能改变；研究H蛋白抗原变异对我国疫苗保护效果的影响。拟阐明我国麻疹流行株的起源、分子进化时间和速率、抗原变异规律及其对H蛋白功能的影响，以及我国分离自半个世纪前的麻疹疫苗株对现流行麻疹本土株和不同输入病毒株的保护效果等科学问题。这些科学研究将对我国是否需要研制新麻疹疫苗提供基础性科学数据，也为我国和全球的麻疹消除提供科学实验依据。另外，也可以阐明和鉴定新基因型D11病毒的抗原表位及相应的结构和功能特征。

The antigenicity of measles virus was considered stable very much for a long time. However, the rate of variation of measles virus might become quicker so that have impact on the protective effect of measles vaccine. Study from foreign country showed that the epitope of wide type measles virus changed; and neutralizing titer of human serum from the vaccinee neutralizing vaccine virus higher than that of wild type viruses. This study is just beginning in China. It is necesarry to study on the molecualr evolution and antigenic variation of measles virus. Based on the 3D crystal structure, dynamic study on the changes of structural and functional characterization of H protein based on the amino acid variation of the epitope will be performed; and we will impletement the experimental study on the impact of these variation on the protective effect of Chinese measles vaccine.The evolutionary time scale and evolution rate, genetic variation and antigenic changes, and the impact of these changes on the protective effect of Chinese vaccine on endemic and imported viruses will be clarified. We will obtain the basic data of cross protection of different genotypes measles viruses. These study could provide the scientific data for the strategy of measles elimination and to evaluate if need to develop a new vaccine. On the other hand, the epitope of new genotype D11 virus could be identified and the structural and functional characterization of neutralizing epitopes of D11 measles viruses will be described.