甲型肝炎减毒活疫苗新疫苗候选株的选育

以甲肝减毒株的早代毒种 (L A 1) /P9,在 35℃条件下培养 ,采用人胚肺二倍体细胞 (2BS株 )连续减毒传代 ,克隆纯化 ,选育出新的疫苗候选株。该毒株经外源因子检查合格。较现行生产用毒株病毒增殖周期缩短 10d以上 ,病毒滴度可提高 1 0LogTCID5 0 ml以上 ,经恒河猴试验表明安全性与现行毒株差异无显著意义 ,而且免疫原性更好。

Selection of Candidate Strain of Live Attenuated Hepatitis A Vaccine

The strain L A 1/P9 of hepatitis A virus was cultured and passaged in human embryo lung diploid cells(2BS strain) at 35℃, then cloned and purified. In this way, a new candidate strain of live attenuated hepatitis A vaccine was selected out. The candidate strain passed foreign factor examination. The result of rhesus test showed good immunogenicity of the candidate in comparison with the current strain, and no significant difference was observed between the safeties of them. The titer of HA vaccine prepared with the candidate increased by more than 1.0 Log compared with that prepared with the current strain, however, the virus proliferating cycle of it decreased by more than 10days.