黑色素瘤小鼠体内CD8^+记忆T细胞亚群特性研究

The characteristics of CD8^+ memory T cell subsets in melanoma mice

目的探讨黑色素瘤小鼠体内CD8+T淋巴细胞亚群的比例变化并对CD8+CD62L+CD127+T细胞亚群的功能做初步研究。方法将B16细胞注入C57/BL小鼠右腋皮下,制备黑色素瘤小鼠模型,4周后处死,用流式细胞术检测脾脏、血液及骨髓细胞中各CD8+T淋巴细胞亚群的比例变化,将升高的CD8+CD62L+CD127+T细胞群与肿瘤细胞共培养,流式检测其凋亡、ELISA检测共培养上清中IFN-γ的分泌水平;将CD8+CD62L+CD127+T细胞体外刺激后用MTT法检测其增殖情况。结果在B16荷瘤小鼠脾脏CD8+CD62L+、CD8+CD127+和CD8+CD62L+CD127+T细胞频率显著高于正常对照小鼠,外周血和骨髓中这些细胞的频率在2组小鼠之间无显著性差异。荷瘤小鼠体内CD8+CD62L+CD127+T细胞亚群IFN-γ分泌的能力低于CD8+CD62L+CD127-T细胞(P<0.05),也明显低于CD8+T细胞(P<0.01)。但相对于CD8+T细胞,CD8+CD62L+CD127+T增殖能力明显增强(P<0.01)而凋亡减弱(P<0.05)。结论 B16荷瘤小鼠脾脏中记忆CD8+T细胞亚群频率升高,而CD8+CD62L+CD127+T细胞亚群有更强的增殖能力和抗凋亡能力,提示小鼠黑色素瘤促进了记忆CD8+T细胞生成且CD8+CD62L+CD127+T细胞可能具有更独特的作用。

To determine the variation of different CD8＋ T cell subsets and the functions of the CD8＋CD62L＋ CD127＋T cell subset in melanoma mice, BI6 cell was injected subcutaneously in right axilla of C57/BL mice to prepare a mouse model of melanoma. Four weeks after, flow cytometry was employed to detect the variation of different CD8＋T cell subsets in spleen, blood and marrow cells of the model mice; and then using flow cytometry to detect the apoptosis and ELISA to detect the IFN-γ secretion after co-cultured CD8＋CD62L＋CD127＋T cells with tumor cells. Furthermore, MTT assay was used to detect the proliferation of CD8＋CD62L＋CD127＋T cells after in vitro stimulation. Results showed that the frequency of CD8＋T cell subsets CD8＋CD62L＋, CDS＋CD127＋ and CD8＋CD62L＋CD127＋T cell was significant higher than that of normal control mice. But the frequency of these cells in blood and bone marrow was no significant difference between the tumor-bearing mice and normal mice. The CD8＋CD62L＋CD127＋T cell subsets in melanoma have lower capacity to secrete IFN-γ as compared with CD8＋CD62L＋CD127＋T cells （P〈0.05） and CD8＋ T cells （P〈 0.01）. Furthermore, for C D 8＋C D62L＋CD127＋T cell subset, their proliferation was significantly increased （P〈 0.01） and apoptosis was significantly diminished （P〈 0.05）, compared with CD8＋T cells. In conclusion, the percentage of memory CD8＋T cell subsets is increased in B16 tumor-bearing mice, while CD8＋CD62L＋CD127＋ cell subsets have a stronger ability of anti-apoptotie and proliferative capacity, suggesting that tumor-bearing mice promotes memory CD8＋T cells generation and CD8＋CD62L＋CD127＋ memory T cells may play more unique roles.