结核分枝杆菌纯蛋白衍生物(PPD)对CD4^+ CD154^+ T细胞的影响

The impact of protein purified derivative on the population of CD4^+ CD154^+ T cell subset

目的通过研究结核分枝杆菌纯蛋白衍生物(PPD)对CD4+ CD154+ T细胞亚群的影响,探讨结核分枝杆菌分泌蛋白的致病性。方法 PPD或/和BCG刺激PBMCs后,用流式细胞术检测活动性肺结核的CD4+ CD154+ T细胞和CD4+IFN-γ+T细胞的比例变化。结果①PPD刺激显著下调CD4+ CD154+ T细胞比例,能够抑制BCG刺激产生的CD4+ CD154+ T细胞的增殖;②PPD刺激CD4+ IFN-γ+ T细胞的效果显著低于BCG。结论 PPD内存在能显著抑制机体保护性免疫的分泌蛋白,可能是结核杆菌进入人体后抑制机体免疫力的重要因素之一。

Objective To study the impact of Mycobacterium tubereulosis（Mtb） protein purified derivative（PPD） on the population of CD4＋CD154＋ T cell subset and to investigate the pathogenicity of the secreted proteins of Mtb. Methods The CD4 ＋ CD154＋ T cells and the CD＋IFN-γ T cell subset were identified with flow cytometry and its population frequencies were examined in patients with pulmonary tuberculosis and controllers with positive PPD reaction after stimulating PBMCs with PPD or/and BCG. Results 1. PPD could significantly inhibit CD4 ＋ CD154＋T cell subset induced by BCG stimulation. 2. Compared with BCG, PPD was much less potent in stimulating the CD4＋ IFN-γ ＋ T cell subset. Conclusion Some secreted proteins in PPD can significantly suppress the T cell immunity to Mtb.