CTLA4Ig修饰的树突状细胞在体外对淋巴细胞增殖及胞毒效应的影响

目的:探讨CTLA4Ig修饰的树突状细胞(DC)对T细胞增殖和细胞毒性T细胞(CTL)细胞毒活性的影响。方法:采用脂质体转染法,将质粒pG/CTLA4Ig转入DC。采用ELISA和SDS-PAGE鉴定转染质粒pG/CTLA4Ig的DC培养上清。以C57BL/6小鼠的单个核细胞作为反应细胞,以未修饰的DC及修饰的DC作为刺激细胞,共培养6 d,用MTT比色法检测细胞的增殖。用乳酸脱氢酶法和ELISA法,分别测定细胞毒活性及T细胞凋亡。结果:CTLA4Ig融合蛋白和修饰的DC,对同种细胞刺激的增殖反应有明显地抑制作用;而未修饰的DC可显著诱导淋巴细胞增殖反应。CTLA4Ig融合蛋白和修饰的DC,对特异性CTL的细胞毒活性有明显地抑制作用,且可诱导T细胞凋亡。结论:稳定表达CTLA4Ig融合蛋白的DC,对T细胞增殖和对CTL的细胞毒活性具有明显地抑制作用,并可诱导T细胞凋亡。

The effect of CTLA4Ig-modified dendritic cells on proliferation and cytotoxicity of lymphocytes in vitro

AIM: To study the effect of dendritic cells (DCs) modified by CTLA4lg on T-cell proliferation and the cytotoxic T lymphocyte killer activity. METHODS: The expressing vector pG/CTLA4lg was transfected into DCs via lipofectamine reagent mediation. CTLA4lg fusion protein secreted by DCs in the culture supernatant was confirmed by sandwich ELISA and SDS-PAGE. Peripheral blood mononuclear cells (PB-MC) from C57BL/6 mice (as reaction cells) and DCs modified or unmodified by CTLA4lg (as stimulation cells) were co-cultured for 6 days. MTT colorimetry was used to detect lymphocyte proliferation. Lactate dehydrogenase release method and sandwich ELISA assay was used to examine the cytotoxic activity and T-cell apoptosis. RESULTS: CT-LA4lg fusion protein and DCs modified by CTLA4lg could significantly inhibit lymphocyte proliferation response and cytotoxic activity of specific cytotoxic T lymphocytes, and induce T-cell apoptosis, while unmodified-DCs could markedly induce lymphocyte proliferation response. CONCLUSION: The DCs of stably expressing CTLA4lg fusion protein could not only markedly inhibit T-cell proliferation and cytotoxic activity of CTL, but also induce T-cell apoptosis.