B7-H1协同刺激淋巴细胞增殖并诱导产生抑制性T细胞

B7-H1 enhances Ag-specific lymphocytes proliferation and induces immunosuppressive T cells

目的:探讨B7-H1分子在抗原诱导的免疫反应中的作用。方法:在可溶性抗原PPD诱导淋巴细胞增殖体系中,加入中和抗体检测B7-H1的协同刺激作用。转染表达B7-H1的ECV304细胞,观测其对PPD诱导的淋巴细胞增殖、细胞因子分泌及淋巴细胞亚群比例的影响。将刺激后的淋巴细胞过继至自体或同种异体增殖体系中,检测其功能。结果:抗B7-H1中和抗体可降低PPD诱导的淋巴细胞增殖反应和细胞因子分泌;转染B7-H1的ECV304细胞可协同刺激抗原诱导的淋巴细胞增殖,促进细胞因子IL-10的表达,并改变T细胞亚群分布,增加CD4+T细胞亚群比例;自体或同种异体过继实验显示,B7-H1刺激后的淋巴细胞具有显著的免疫抑制功能。结论:B7-H1分子可协同刺激淋巴细胞增殖并诱导产生具有免疫抑制功能的T细胞亚群。

To investigate the function of costimulatory factor B7-H1 in antigen-specific immune response. Methods ：The effect of B7-H1 in soluble antigen（PPD）-induced lymphocyte proliferation was detected by using anti-B7-H1 neutralizing antibody. Then, B7-Hl-transfected ECV304 cell line and mock-transfected control were used to stimulate PPD-induced lymphocytes, respectively, which were examined for proliferation, cytokines secretion, cytokine mRNA level and changes of T cell subsets. The function of T cell stimulated with the B7-Hl-transfected ECV304 cell line was also inspected through autoor aUo-lymphocyte adoptive transfering assay. Results：Antigen-specific lymphocyte proliferation and cytokine secretion were inhibited by anti-B7-H1 neutralizing antibody. Compared with mock-transfected control, the B7-Hl-transfected ECV304 cells enhanced the proliferation of PPD-stimulated lymphocytes, promoted the secretion of IL-10 and expression of its mRNA. Besides, the ratio of T cell subsets was also changed owing to the enlargement of CD4^＋ T cell populations. In adoptive transfering assay, lymphocytes stimulated with the B7-Hl-transfected ECV304 cells markedly inhibited autoor aUo-lymphocytes proliferation. Conclusion： Costimulatory factor B7-H1 could enhance antigen-specific lymphocytes proliferation and induce some T cell subset with immunosuppressive activity.