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目的:利用载有Foxp3基因的腺病毒载体转染,使小鼠CD4+CD25-T细胞强制性高表达Foxp3,并研究体外诱导获得的Foxp3高表达T细胞对NK细胞免疫活性的调节作用及其机制。方法:将载有Foxp3基因的逆转录病毒转染CD4+CD25-T细胞获得持续性高表达Foxp3的CD4+T细胞。CD4+Foxp3+T细胞与NK细胞共培养后,通过51Cr标记法检测NK细胞的杀伤毒性。在Transwell共培养实验体系中,通过TGF-β阻断实验来检测NK细胞杀伤毒性。结果:通过逆转录病毒转染幼稚CD4+CD25-T细胞获得了表达Foxp3的CD4+T细胞模型。CD4+Foxp3+T细胞在与NK细胞共培养后,能显著抑制NK细胞毒性杀伤作用。在共培养体系中加入抗TGF-β抗体后,其抑制率显著降低。与NK细胞直接接触的CD4+Foxp3+T细胞可以诱导NK细胞免疫抑制。结论:强制性表达Foxp3的CD4+CD25-T细胞可以在体外发挥免疫抑制作用,能抑制NK细胞的细胞毒性杀伤作用。转染Foxp3的CD4+CD25-T细胞对NK细胞发挥作用依赖于细胞之间的直接接触,与转染后T细胞表面表达TGF-β有关。
AIM: To investigate the regulatory effect of Foxp3-overexpressing T cells induced by NK cells in vitro on Foxp3 expression in CD4 + CD25-T cells transfected with adenoviral vector carrying Foxp3 gene and its regulation mechanism. Methods: CD4 + CD25-T cells were transfected with retrovirus containing Foxp3 gene to obtain CD4 + T cells with persistent high expression of Foxp3. After CD4 + Foxp3 + T cells were co-cultured with NK cells, NK cell cytotoxicity was detected by 51Cr labeling. In the Transwell co-culture system, cytotoxicity of NK cells was tested by TGF-β blocking assay. Results: CD4 + T cells expressing Foxp3 were obtained by retrovirus transfection of naive CD4 + CD25-T cells. CD4 + Foxp3 + T cells can significantly inhibit NK cytotoxicity after co-cultured with NK cells. After the anti-TGF-β antibody was added into the co-culture system, the inhibition rate was significantly reduced. CD4 + Foxp3 + T cells that are in direct contact with NK cells can induce NK cell immunosuppression. CONCLUSION: CD4 + CD25-T cells that constitutively express Foxp3 can exert immunosuppressive effects in vitro and inhibit the cytotoxicity of NK cells. CD4 + CD25-T cells transfected with Foxp3 play a role in NK cells on the direct contact between cells, which is related to the expression of TGF-β on the surface of T cells after transfection.