表达结核杆菌抗原的重组酿酒酵母免疫小鼠研究

Induction of Antigen-specific Humoral Immune Response by Subcutaneous Vaccination with Saccharomyces cerevisiae Expressing Mycobacterium tuberculosis Antigen

近年来研究显示全细胞重组酿酒酵母疫苗具有治疗性疫苗潜能.为了研究重组酿酒酵母结核病候选疫苗的免疫效果,将IFN-γ基因与结核杆菌抗原蛋白Ag85B、ESAT6的基因融合,利用pHR酿酒酵母表达系统和同源重组方法,成功构建了以酿酒酵母Y16为宿主的表达融合蛋白IFN--γAg85B和IFN--γESAT6-Ag85B的重组酿酒酵母.Western blot证实了融合蛋白IFN--γAg85B、IFN--γESAT6-Ag85B在重组酵母内能有效表达.将热失活后的重组酿酒酵母全细胞以皮下注射方式免疫小鼠,ELISA检测小鼠血清抗体,结果显示:重组酵母能够有效激发小鼠产生Ag85B特异性IgG抗体,免疫后3周后的IgG效价明显高于免疫2周的,与表达IFN-γ-Ag85B的重组酵母相比,表达IFN--γESAT6-Ag85B的重组酵母能够更有效地诱导小鼠免疫细胞Th1型反应.

Recent studies have suggested that whole recombinant Saccharomyces cerevisiae acts as a potent therapeutic vaccination against infectious diseases.For the purpose to develop novel and more efficacious vaccines against tuberculosis,IFN-γ was fused with Mycobacterium tuberculosis antigens Ag85B and ESAT6-Ag85B,and expressed in S.cerevisiae Y16 using pHR S.cerevisiae expression system.Western blot demonstrated that fusion proteins IFN-γ-Ag85B（IA） and IFN-γ-ESAT6-Ag85B（IEA）were expressed successfully in yeast.Humoral immune response in mice was investigated after subcutaneous vaccination with the heat-killed whole recombinant yeasts Y16-IA and Y16-IEA.Both Y16-IA and Y16-IEA could induce high Ag85B-specific IgG response,and IgG titer in mouse serum after vaccination 3 times increased significantly than that after vaccination 2 times.Compared with Y16-IA,Y16-IEA increased IgG2a/IgG1 ratio,which indicated that recombinant yeast Y16-IEA could induce Th1 type response more effectively than Y16-IA.These results suggest that recombinant S.cerevisiae expressing M.tuberculosis antigen may be developed to be an effective vaccine candidate for the control of tuberculosis.