H_2株甲肝减毒活疫苗K_7的核苷酸全序列分析

Complete Nucleotide Sequence of the Live Attenuated Hepatitis A Vaccine K 7 (from H 2 Strain)

应用ＲＴ－ＰＣＲ获取Ｈ２株甲肝减毒活疫苗（Ｋ７）的ｃＤＮＡ片段，经末端终止测序ＰＣＲ试剂盒和全自动测序仪（ＡＢＩ３７７）作序列测定，用Ｍａｘｔｒｉｇｅｎｅ软件进行计算机分析，Ｋ７疫苗病毒的核苷酸全长含７４４３个碱基．Ｋ７对比其亲代Ｈ２株，减毒的ＨＭ１７５株以及ＨＭ１７５野毒株，同源性分别为９９．７５％，９９．９５％和９９．６１％；彼此间在Ｐ１和Ｐ２连接区１６８个碱基的同源性为９９．４％～１００％，均为ⅠＢ基因亚型．前三者在５’非编码区均有１３１～１３４位和２０３位５个碱基缺失，且结构蛋白基因区序列完全一致．本文用分子病毒学方法证实了Ｋ７疫苗的优异纯毒水平。

Eight cDNA fragments overlapped each other have be en obtained from th e live attenuated hepatitis A vaccine K 7,the progeny viruses of H 2 strain b y R T-PCR.A total of 21 fragments were sequenced with the dye termiantor cycle seque ncing kit and automatic sequence equipment model 377(ABI corp.).By using the sof tware of Maxtrigene,the complete nucleotide sequence of K 7 cDNA has been deter mined and analyzed.An entire length of 7443 bases was evidenced for the s equence of K 7 virus with homology rate of 99.75%,99.61% and 99.95% against its parenta l H 2 atrain,HM 175 strain and the attenuated HM 175 (HM 175 ATD) .According to the d ifferences in the 168 bases located at the joint site of P1 and P2 region,the ge notype of K 7,H 2 as well as HM 175 should be classified into ⅠB subgeno type.The K 7,H 2 and HM 175 ATD have showed the same deletion of nucleotide 131 1 34 and 203 at the 5'non encoding area,and also the identical sequence for encoding the s tructural protein.The result of this study has demonstrated the high purity of K 7 vaccine with the technique of molecular virology and provided the basic info rm ation for carrying out the molecular epidemiologic investigation for hepatitis A .