三个HIV-1广谱中和表位与HBV S抗原融合表达可诱导小鼠特异性抗体应答

为了增强HIV-1交叉中和表位的免疫原性,本研究使用PCR克隆技术将HIV-1三个具有一定广谱中和活性的线性抗原表位ELDKWA(简称2F5)、NWFDIT(简称4E10)和GPGRAFY(简称447-52D)基因分别融合到HBV S基因的3味端,构建了分别表达这三种融合基因的天坛株重组痘苗病毒疫苗RVJ1175S-2F5、RVJ1175S-4E10和RVJ1175S-447-52D,使用这三种重组痘苗病毒感染的细胞培养上清液经分离纯化制备了三种相应的蛋白亚单位疫苗PS-2F5、PS-4E10和PS-447-52D,对重组痘苗病毒和亚单位疫苗中三种融合抗原的生物学及免疫学特性进行了比较研究.PCR和测序结果表明,三种融合基因序列正确重组到痘苗病毒TK区,HBsAg的ELISA检测表明三种融合蛋白有效表达并分泌到细胞培养上清液中,SDS-PAGE凝胶电泳显示三种纯化后的融合蛋白均含分子量为23kD和27kD两种典型HBsAg条带,Western blot证明这两个条带均能与HBsAg抗体反应,并分别能与三种表位相应的HIV-1单抗2F5、4E10和447-52D反应.小鼠免疫结果显示,三种重组痘苗病毒疫苗和三种蛋白亚单位疫苗均能诱发较高水平的HBsAg抗体和相应HIV-1交叉中和表位抗体,蛋白亚单位疫苗诱生的这两类抗体均明显高于对应的重组痘苗病毒疫苗.这些结果为进一步研究三种表位抗体的中和活性和通过不同类型疫苗联合免疫进一步增强其免疫效果研究奠定了基础.

Vaccination with Three HIV-1 Cross Neutralizing Epitopes Fused to HBV S Antigen Could Induce Robust Antibody Immune Response in Mice

To enhance immunogenicity of HIV-1 cross neutralizing epitopes , three HIV-1 cross neutralizing epitopes (ELDKWA, NWFDIT, GPGRAFY) were fused to 3' end of HBV S gene by PCR cloning technology, respectively. Three vaccinia virus (Tiantan strain) recombinants expressing separately the three fusion genes were subsequently constructed, named as RVJ1175S-2F5 (ELDKWA), RVJ1175S-4E10 (NWFDIT) and RVJ1175S-447-52D (GPGRAFY), respectively. From the supernatants of CEF cells infected by these vaccinia recombinants, three subunit vaccines (PS-2F5, PS-4E10 and PS-447-52D) were prepared after purification. Biology and immunology characteristics of these fusion antigens in vaccinia recombinants and subunit vaccines were comparatively studied. It was confirmed by PCR and sequencing that the fusion genes were inserted into the TK locus of vaccinia virus (Tiantan strain) correctly. The Fusion proteins were expressed efficiently and secreted into supernatant of the infected cells, which was demonstrated by HBsAg ELISA test. Two typical HBsAg bands of 23kD and 27kD were detected in all the purified samples by SDS-PAGE. These two bands were reacted well to HBsAb and corresponding HIV-1 monoclonal antibodies 2F5, 4E10 and 447-52D. BALB/c mice were immunized with subunit and vaccinia recombinant vaccines by intraperitoneal injection. High levels of HBsAb and anti-HIV-1 cross neutralizing epitope antibody in peripheral blood of immunized mice were tested by ELISA, and all the antibody titers induced by three subunit vaccines were higher than that induced by correlated vaccinia recombinants in mice. This work provides a basis for future study on neutralizing activity of these immunized sera and enhancing immune effect through the combined immunization with different type of vaccines.