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目的 考察麻疹S191疫苗株在长期传代过程中HA基因的变化 ,以确定用于生产的最佳代次。方法 对麻疹S191疫苗株鸡胚细胞系 (CEC) 2 0、30代病毒株及S191株羊膜系病毒株 (强毒 )HAM42的血凝蛋白 (HA)基因进行RT—PCR ,克隆到PUC质粒后进行测序。结果 2 0代和 30代疫苗的HA基因的 185 4个碱基序列中未出现核苷酸的变化 ,但二者与HAM42株相比有两个核苷酸的变化 ,分别在 15 17和 1799位 ,并导致 5 0 6位的Gly变为Asp ,6 0 0位的氨基酸由Glu变为Val。结论 麻疹病毒的减毒株与强毒株存在差异。而麻疹减毒株在鸡胚细胞的长期传代中 ,HA基因未出现明显变化 ,没有出现抗原漂移 ,30代毒株与 2 0代毒株是一致的
Objective To investigate the changes of HA gene in long-term passage of Measles S191 vaccine strain to determine the best generation for production. Methods The hemagglutinin (HA) gene of 20, 30, and 20 S191 vaccine strains of chick embryo cell line (CEC) and H1942 strain of S191 strain were amplified by RT-PCR and cloned into PUC plasmid Sequencing. Results There was no nucleotide change in the 185 4 base sequences of the HA gene of the 20 generation and 30 generation vaccines, but there were two nucleotide changes compared with the HAM42 strain, respectively, at 15 17 and 1799 Resulting in the Gly at position 506 becoming Asp and the amino acid at position 600 changing from Glu to Val. Conclusion There is difference between attenuated and virulent strains of measles virus. In the long-term passages of chick embryo cells, there was no significant change in the HA gene and no antigen drift occurred in the attenuated strain of measles. The 30-generation strain was consistent with the 20-generation strain