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目的研究沪191麻疹病毒疫苗株(S191)在原代鸡胚成纤维细胞中连续传代的基因稳定性,为评估和控制麻疹疫苗的免疫原性及安全性提供依据。方法取S191的22代冻干主种子批在SPF原代鸡胚成纤维细胞上连续传代获得的23、26(用于生产的疫苗代次)、29、31和33代病毒液,提取病毒RNA,RT-PCR扩增后,进行全序列测定,并对病毒关键的保护性抗原进行核苷酸和氨基酸序列分析。结果与22代全基因比较,核苷酸序列同源性:26代为99.96%,33代为99.92%;氨基酸序列同源性:26代为99.98%,33代为99.89%。26代疫苗病毒仅M蛋白第123位氨基酸由苏氨酸→赖氨酸,33代病毒有5个氨基酸差异。结论 26代S191麻疹疫苗疫苗病毒的基因结构高度稳定,疫苗可保持主种子病毒的免疫原性和安全性。
Objective To study the genetic stability of Shanghai 191 measles virus vaccine strain (S191) serially passaged in primary chick embryo fibroblasts and to provide basis for evaluating and controlling the immunogenicity and safety of measles vaccine. Methods Twenty-two generations of lyophilized main seeds of S191 were serially passaged on SPF primary chick embryo fibroblasts to obtain 23,26 (vaccine generations for production), 29,31 and 33 generations of virus solution, and viral RNA was extracted After amplification by RT-PCR, the whole sequence was determined and nucleotide and amino acid sequence analysis was performed on the virus-specific protective antigen. Results Compared with the whole genome of 22 generations, the nucleotide sequence homology was 99.96% for 26 generations and 99.92% for 33 generations. The homology of amino acid sequence was 99.98% for 26 generations and 99.89% for 33 generations. 26 generation vaccine virus only M protein 123 amino acids from threonine → lysine, 33 generations of the virus has five amino acid differences. Conclusion The genetic structure of 26 generation S191 measles vaccine virus is highly stable. The vaccine can maintain the immunogenicity and safety of the main seed virus.