重组结核分枝杆菌多表位肽的免疫原性研究

Investigation into Immunogenicity of Multiepitope Polypeptide from Mycobacterium Tuberculosis

目的探讨纯化的重组结核分枝杆菌多表位肽激发细胞毒性T淋巴细胞(Cytotoxic Tlymphocyte,CTL)免疫应答的能力,为新型结核疫苗的设计打下基础。方法通过细胞增殖和细胞毒性实验,研究纯化的重组表达多表位肽刺激外周血单个核细胞(PBMC)产生的增殖反应和细胞毒活性,初步鉴定重组多表位肽的免疫原性。结果以刺激系数(SI)>3为界,多表位肽(10μmol)能刺激全部10例HLA-A*0201阳性(A2+)结核菌素阳性(PPD+)健康个体的PBMC发生增殖,SI为46.2±5.6;增殖反应明显高于单肽(平均SI为10.2±2.3)以及PPD(平均SI为15.6±3.6)引起的细胞增殖反应(P<0.01)。在多表位肽诱导的CTL细胞毒活性分析中以负载抗原肽(10μmol)的T2细胞作为靶细胞,多表位肽诱导的CTL作为效应细胞,多表位肽能诱导全部的10例A2+PPD+健康个体中CTL杀伤活性,平均活性分别为(86.2±9.6%),显著高于单肽[平均为(25.4±3.6)%]和PPD[平均为(22.6±2.8)%](P<0.01)。结论重组优化多表位肽在细胞水平具有较好的免疫原性,能有效刺激PBMC产生细胞增殖反应和细胞毒活性。

Objective To investigate into the immunogenicity of the polypeptide with multiepitopes from mycobacterium tuberculosis （Mth）. Methods Experiment upon cellular proliferation and cytotoxicity were performed for the evaluation of the immunogenicity of recombinant polypeptide with multiepitopes from Mth. Results Polypeptide with multiepitopes （ 10μm） could stimulate the proliferation in peripheral blood monocyte （PBMC） from all of the ten HLA-A ＊ 0201 positive （ A2^＋ ） healthy subjects with PPD ^＋, strikingly stronger than that of single peptide＇ s or PPD＇ s group （ average stimulation index as 46. 2 ± 5.6 versus 10.2 ± 2.3 or 15.6±3.6 respectively, P 〈0.01 ）. Cytotoxic T lymphocytes （CTLs） induced by multiepitope polypeptide were used as effector cells in CTL assay against T2 cells loaded with single peptide （ 10μm）. Multiepitope polypeptide could induce CTL cytotoxity in all of the ten A2^＋ and PPD^＋ healthy subjects, significantly higher than that of the single peptide＇ s or PPD＇ s group （ average activity as 86.2 ± 9.6% versus 25.4 ± 3.6% or 22.6 ± 2.8% , P 〈 0.01 ）. Conclusion The recombinant multiepitope polypeptide from Mth can stimulate greater proliferation and cytotoxicity of PBMC, which is helpful for designing new vaccines.