结核分枝杆菌海藻糖磷酸磷酸酶诱导小鼠体液和细胞免疫应答

Humoral and cellular immune responses in mice induced by trehalose-6-phosphate phosphatase from mycobacterinm tuberculosis

目的 研究结核分枝杆菌（M．tuberculosis）海藻糖磷酸磷酸酶（TPP）诱导小鼠体液和细胞免疫。方法 差速离心分离结核分枝杆菌H37Rv和卡介苗（BCG）的各细胞组分，通过Western杂交检测抗原TPP在结核分枝杆菌H37Rv和BCG中的亚细胞定位情况。分别用5×10^6 CFU的BCG和50μg的TPP蛋白免疫C57BL／6小鼠，检测小鼠血清中抗TPP的IgG1和IgG2a抗体效价。取免疫小鼠的脾细胞，体外抗原刺激，用酶联免疫斑点试验（ELISPOT）检测γ干扰素（IFN-γ）分泌细胞。结果 TPP亚细胞定位于结核分枝杆菌H37Rv和BCG的胞壁和细胞膜组分。TPP蛋白免疫后小鼠产生的TPP特异性IgG1和IgG2a抗体效价明显高于BCG免疫小鼠，并且IgG2a的抗体效价高于IgG1。体外抗原刺激TPP蛋白和BCG免疫小鼠的脾细胞，都能诱导较高的IFN-γ分泌。结论 结核分枝杆菌细胞壁蛋白TPP能诱导小鼠Ⅰ型辅助性T细胞介导的免疫反应，可作为抗结核疫苗的候选抗原。

Objective To study the humoral and cellular immune response in mice induced by trehalose-6-phosphate phosphatase （TPP） purified from Mycobacterium tuberculosis. Methods Different cellular components of M. tuberculosis H37Rv and Mycobacterium bovis bacillus Calmette-Guérin （BCG） were separated by differential velocity centrifugation, and the subcellular localization of TPP in M. tuberculosis H37Rv and BCG was examined by Western blot. C57BL/6 mice were immunized with BCG （5×10^6 CFU） or TPP （50 μg protein）. The titers of TPP-specific IgG1 and IgG2a antibody responses were tested by ELISA. Splenocytes were stimulated with TPP and assayed for the interferon-γ secretion by Enzyme-linked Immunospot Assay （ELISPOT）. Results The subcellular localization of TPP was determined to be in the cell wall and cell membrane of M. tuberculosis H37Rv and BCG. The IgG1 and IgG2a titers in the TPP protein immunized mice were higher than those in the BCG-immunized group, and the IgG2a titers were higher than the IgG1 titers. Splenocytes from mice vaccinated with either TPP protein or BCG all produced IFN-γ when stimulated in vitro with TPP protein. Conclusion TPP from M. tuberculosis mainly induces Thl type immune response in mice, and it may serve as a potential vaccine candidate against tuberculosis.