人类免疫缺陷病毒1型HXB2株Tat突变体的构建、原核表达及免疫原性分析

目的 构建HIV-1 HXB2株Tat基因半胱氨酸富集区3'末端移位突变体,经原核表达和纯化,分析该突变体蛋白(Tat-cct)的免疫原性.方法 用PCR方法将HIV-1 HXB2株Tat基因的半胱氨酸富集区(64～111位核苷酸)移位至Tat基因的3'末端,获得其突变体DNA序列,并构建其原核表达质粒pET32a-Tat-cct,转入大肠埃希菌E.coli BL21(DE3)中进行诱导表达及纯化.以Tat-cct融合表达蛋白免疫BALB/c小鼠,ELISA方法对该抗血清进行免疫原性检测分析.结果 pET32a-Tat-cct重组质粒可在E.coli BL21(DE3)中诱导表达,纯化后其融合蛋白相对分子质量约为31 000.Tat-cct重组蛋白免疫小鼠诱导产生的抗体滴度为1:1600,该抗体与Tat-cct蛋白和Tat蛋白(1～101位氨基酸)均呈特异性结合反应.结论 Tat突变体重组蛋白Tat-cct能在大肠埃希菌中有效表达.并较好保留其免疫原性,为HIV-1 Tat疫苗的基础研究提供了有价值的实验结论.

Construction, prokaryotic expression and immunogenic analysis of HXB2 subtype Tat mutant of human immunodeficiency virus type-1

Objective To construct shifting mutant of cysteine-rich region to 3?@terminal of Tat gene of human immunodeficiency virus type-1 (HIV-1) HXB2 strain, and to analyze the immunogenicity of mutant protein (Tat-cct) after prokaryotically expressed and purified. Methods The cysteine-rich region (nucleotides 64--111) of Tat gene was shifted to 3'terminal of Tat of HIV-1 HXB2 strain by polymerase chain reaction (PCR) and Tat mutant DNA sequence was obtained. Prokaryotie express plasmid pET32a-Tat-cct was constructed and transformed into E. coli BL21 (DE3), then Tat-cct protein was expressed and purified. BALB/c mice were immunized with the fusion protein Tat-cct, and immunogenicity of the immunized serum was detected by enzyme-linked immunosorbent assay (ELISA). Results The recombinant plasmid pET32a-Tat-cct expressed in E. coli BL21 (DE3) and the relative molecular mass of the purified fusion protein was 31 000. The serum antibody titer of mice immunized with Tat-cct recombinant protein was 1 : 1600, which binded specifically with both Tat-ect protein and Tat protein (amino acids 1-101). Conclusions The recombinant protein Tat-cct of Tat mutant strain can be expressed efficiently in E. coli and well retains immunogenicity, which provides valuable information for basic research of HIV-1 Tat vaccine.