大肠杆菌合成的乙型肝炎病毒核心抗原(HBcAg)转化为e抗原(HBeAg)的探索

本文以带有HBcAg基因重组质粒的大肠杆菌转化株Ecoli MM206所合成的HBcAg进行HBcAg转化为HBeAg的探索研究。菌经超声破碎获得的菌裂解液对生理盐水透析两天后,酶联检测发现抗原性部分转化为HBeAg。将菌裂解液或HBcAg精制品用2-巯基乙醇处理,可使抗原性发生进一步转化。但是分子筛层析证明抗原蛋白分子大小没有明显变化。这种制品有可能作为诊断试剂用以检测抗-HBe,而且实验结果表明HBeAg是由HBeAg衍变来的。为要提高HBeAg的稳定性,以碘乙酰胺处理,使还原的抗原蛋白通过羧甲基化反应封闭游离的巯基。经上述处理的HBeAg通过分子筛层析可与大部分细菌杂蛋白分开,制品只有HBeAg活性而测不到HBeAg活性,因而提高了抗原蛋白的稳定性与纯度。

ANTIGENIC CONVERSION OF HEPATITIS B CORE ANTIGEN SYNTHESIZED IN E.Coli INTO e ANTIGEN

In the study of antigenic conversion from HBcAg to HBeAg cells from E.coli MM 206 carrying a recombinant plasmid containing HBcAg gene was used. After two days dialysis against saline, the HBcAg in the bacterial lysate was partially converted into HBeAg.Further conversion was achieved by treating the bacterial lysate or partially purified HBcAg with β-mercaptoethano1.No appreciable change was found in the molecular size of HBcAg after reduction.The result demonstrated that HBeAg is derived from HBcAg and the preparation obtained could be used as the diagnostic reagent to detect anti-HBe. For blocking the released SH groups, iodoacetamide was used to perform the carboxymethylation of the reduced protein.The carboxymethylated reduced HBeAg may be separated from most of the bacterial proteins by gel filtration amd no HBcAg activity could be detected in ELISA assay.