小鼠γδT细胞抗原呈递功能的实验研究

Study on the antigen presenting function of murine gamma delta T cells

目的:证实小鼠γδT细胞抗原也具有呈递功能。方法:观察了高度纯化的小鼠γδT细胞体外激活后MHCⅡ分子及其他共刺激分子的表达与其表面特征性TCR的关系。用自身反应抗原IRBP/MOG特异性T细胞株作为反应细胞,以增殖反应及细胞因子表达作为效应指标,观察γδT细胞的抗原呈递功能。结果:小鼠γδT细胞在激活后可表面表达MHCⅡ分子,并能有效呈递抗原给T细胞,使之发生抗原特异性免疫应答。结论:小鼠γδT细胞具有抗原呈递功能,在启动特异性免疫应答的过程中起重要作用。另一方面,不象人γδT细胞,表达MHCⅡ分子限于新激活的小鼠γδT细胞,后者失去了表面γδTCR。当γδT细胞重新获得表面γδTCR时,其MHCⅡ抗原表达则逐渐减少。

Objective：To elutriate if highly purified murine γδT cells are capable of expressing MHC class Ⅱ antigens and co-stimulatory molecules whereby to elucidate that the activated murine γδT cells are able to function as antigen-presenting cells. Methods： Highly purified γδT cells were obtained from B6 mice induced for AEAU after culture in vitro and selected with MACS. The purified γδT cells were activated by anti-CD3 monoclonal antibody, and were analyzed for the expression of MHC Ⅱ and other co-stimulatory molecules by FACS. Furthermore, the activated γδT cells were used as antigen presenting cells with the IRBP or MOG specific T cells as responder cells. The proliferation and cytokine production by the responder cells were measured. Results： Unlike human γδT cells, the expression of MHC class Ⅱ molecule by murine γδT cell limited to newly activated cells. High levels of MHC class Ⅱ antigen were enriched on activated γδT ceils that lost surface γδ TCR. The MHC class antigens declined gradually while the γδT ceils were regaining their surface TCR. Furthermore, the activated γδT cells expressing MHC Ⅱ molecule were shown the capability of specific antigen presenting function by remarkably enhancing the proliferation and cytokine production by responder T cells. Conclusion：The results suggest that murine γδT cells could express MHC Ⅱ and other co-stimulatory molecules and function as antigen presenting cells.