HBsAg交叉抗原表位的存在及其临床意义

目的探讨牛血清HBsAg样蛋白的性质,为HBV的发病机制、防治等研究提供新思路。方法采集HBsAg样蛋白阳性的牛血清,以质谱对其进行序列测定;以DNAstar软件对蛋白质表位进行分析;以二维凝胶电泳分离的HBsAg样蛋白免疫小鼠,获得抗血清,Western blot分析HBsAg和抗牛HBsAg样蛋白抗血清的交叉反应性。结果发现该目的蛋白为牛血清中的载脂蛋白A-Ⅰ(ApoA-Ⅰ),经Blast显示HBsAg与ApoA-Ⅰ无同源性。生物学软件分析进一步显示,虽然两种蛋白质在一级结构水平无任何同源性,但HBsAg的41-74aa位与ApoA-Ⅰ的37-73aa位氨基酸可能存在交叉表位;Western blot分析证明牛ApoA-Ⅰ与HBsAg存在交叉反应。结论牛血清ApoA-Ⅰ与HBsAg具有交叉表位,该蛋白在HBV的防治中可能具有重要的意义。

Significance of cross-epitopes between bovine serum apolipoprotein A-Ⅰand HBsAg

Objective To investigate the characteristics of an HBsAg-like protein in the bovine sera. Methods SDS-PAGE and mass spectrum were applied for identification of the characteristics of the protein. Blast and DNAstar software were used to compare the epitopes of Apo A -I and HBsAg. At the same time, Western blot was used to analyze the cross-reaction of two kinds of proteins. Results A specific apex acquired by MS and the analysis for peptides showed that it was the Apo A- I , which reacted with anti-HBs antibody. HBsAg and Apo A- I were blasted for comparison in PubMed and there was no homology between them in primary structure. But analysis for B-cell epitopes by biologic software showed that although they were not similar in linear structure, there existed cross-epitope between 41-74aa of HBsAg and 37-73aa of Apo A- I There also existed cross-reaction between HBsAg and Apo A- I by Western blot. Conclusions There exists cross-epitopes between HBsAg and Apo A I , which may be useful to the study of hepatitis B.