EGFR/HER2联合多肽表位疫苗的构建及体液免疫学分析

构建以乙肝病毒核心抗原(HBcAg)为载体的带有1个EGFR和2个HER2的模拟B细胞表位多肽的融合表达质粒pET28a/HBcAg-△n,表达出融合蛋白并纯化,通过免疫BALB/c小鼠获得抗目的蛋白的抗体。采用PCR法将3个模拟表位插入HBc序列的第78～79位,再将该序列克隆入pET28a载体中,构建重组表达质粒,用大肠杆菌BL21(DE3)作宿主菌表达出融合蛋白HBHE,纯化后免疫BALB/c小鼠,检测小鼠的体液免疫应答。测序结果表明,重组质粒构建成功,SDS-PAGE电泳显示融合蛋白表达正确,ELISA检测到高滴度抗体。以HBcAg为载体的B表位被成功表达和纯化,获得高滴度的与3个B表位结合的抗体,为进一步研究HER家族成员联合多肽表位疫苗的广谱抗肿瘤作用奠定了基础。

Construction and immunological analysis of a combined multi-epitope vaccine against EGFR/HER2

A recombinant plasmid pET28a-HBcAg-delta n was constructed, in which three mimic B-epitopes of HER family were inserted into the truncated HBc vector. The fusion protein expressed was purified and used to immunize BALB/c mice to induce antibody against the epitopes. Three mimic epitope genes were inserted into the sequences of amino acid residues 78 and 79 of HBcAg by overlap PCR. The PCR product was then cloned into pET28a to construct recombinant expression plasmid which was transformed to E. coli BL21 (DE3) and induced by IPTG. After purification, the fused protein designed HBHE was used to immunize BALB/c mice to detect humoral immunoresponse. The recombinant plasmid was successfully constructed by DNA sequencing analysis. A fusion protein with correct molecular mass was expressed and confirmed by SDS-PAGE. High titre antibody was elicited in the mice immunized with HBHE by indirect ELISA and Western blotting. The HBc particle vector containing three B-epitopes of HER family had been successfully prepared, purified and high titre antibody against HBHE was detected. All these data are helpful in further research of the broad-spectrum anti-tumour effect of combine polypeptide epi-position vaccine of EGFR and HER2.