H2株甲肝病毒经KMB17细胞培养的毒力及核苷酸序列

目的　监测H2株甲肝病毒经人胚肺二倍体细胞KMB17培养的毒力 /减毒水平及核苷酸序列。方法H2株甲肝减毒活疫苗H2M2 0K7(K7)用KMB17细胞增殖 ,分别在 35℃和 37℃连续传代后 ,抽查不同代次病毒的普通狨猴接种反应和核苷酸片段序列。结果　H2 KMB17系统在 35℃培育 16代次过程中 ,病毒的抗原滴度和感染性滴度稳定 ,在 37℃的滴度明显低下 ,经 13代次仍未达亲本水平。K18(35℃ ,11代 )和K15 (37℃ ,8代 )病毒经普通狨猴接种反应证实为减毒性质。核苷酸两片段共 1897个碱基的序列分析显示 ,K18和K15与K7的同源性高达 99 3%～ 10 0 %。结论　K7疫苗病毒在KMB17细胞培养经 35℃和 37℃连续传代 ,无毒力回升和遗传稳定性改变

Virulence and Nucleotide Sequences of HAV (H2 Strain) Cultured in KMB17 Cell

Objective To detect the virulence/attenuation level and nucleotide sequences of HAV(H2 strain) cultured in human fetal lung diploid cell KMB17.Methods Live attenuated HA vaccine virus H2M20K7(K7) was proliferated in KMB17 cells and passaged at 35 and 37℃, then the immune responses of different passages in common marmosets were observed, and the nucleotide sequences of them were analyzed.Results The antigenic and infectious titers of HAV were stable during culture at 35℃ for 16 passages. However, the titers decreased significantly at 37℃ and were still lower than those of parent virus after 13 passages. K18(35℃, 11 passages) and K15(37℃, 8 passages) were proved to be attenuated by marmoset experiment. The nucleotide sequencing of 2 fragments consisting of 1897 bases showed that 99.3%-100% of K18 and K15 were homologous to K7.Conclusion No virulence reversion was observed in the K7 virus cultured in KMB17 cell at 35 and 37℃, and the hereditary stability of it has not changed.