疟疾感染模型中小鼠T淋巴细胞亚群TCF-1表达情况分析

Effects of TCF-1 in mouse T lymphocytes during malaria infection

目的观察疟疾感染时小鼠T淋巴细胞亚群TCF-1表达情况。方法用感染约氏疟原虫P. y 17XNL的红细胞2×10~5个腹腔接种C57BL/6J小鼠,分别于感染后的第7天、第14天和第21天用多色流式细胞术检测小鼠脾脏淋巴细胞的表型和功能。结果在疟疾感染过程中,CD4^+T细胞不同亚群TCF-1表达量有差异,单个滤泡辅助T细胞(follicular helper T cells,Tfh)要显著高于非滤泡辅助T细胞(non-Tfh)。在疟疾感染的不同时间点(第7天、第14天和第21天),TCF-1在Tfh中的表达逐渐降低,分别为90%、80%和70%。在抗疟疾免疫反应进程中,CD8^+T细胞同一亚群表达TCF-1的量没有变化。但是在感染的同一时间点,CD8^+T细胞不同亚群表达TCF-1的量不同。与KLRG^1(hi)IL-7α-SLEC(短命效应细胞)相比,KLRG^1(lo)IL-7α^+MPEC(记忆前体细胞)中TCF-1的表达量明显增高,频率约为90%。结论 TCF-1对CD4^+T细胞和CD8^+T细胞的抗疟疾功能可能有着重要作用。

T lymphocytes play an essential role in controlling plasmodium, which is the pathogen of malaria,but the mechanism under this phenomenon is not clearly understood. It was reported that T cell factor-1(TCF-1) is of great significance in both CD4+T subsets and CD8+T subsets. In order to understand the role of TCF-1 in T lymphocytes during malaria infection, C57 BL/6 J TCF-1 reporter mice were intraperitoneally(i.p.) injected with 2×105 Plasmodium yoelii 17 XNL(P. y 17 XNL)-infected red blood cells(RBCs)(P. y-iRBCs), and randomly arranged to three groups, as 7 days post infection group, 14 days post infection group and 21 days post infection group respectively. At 7, 14 and 21 days post infection, TCF-1 expression in both CD4+ and CD8+T subset were detected by flow cytometry staining. Data showed that the mean fluorescence intensity(MFI) of follicular helper T cells(Tfh)is moderately higher than that of non-follicular helper T cells(non-Tfh) and the frequency of TCF-1+Tfh at 7, 14 and 21 days post malaria infection was 90%, 80% and 70%, respectively, which indicated that TCF-1 may plays a more significant role in primary differentiation than in maintenance of Tfh. Besides, we found that TCF-1 expression in KLRG1loIL-7α+ memory precursors is much higher than that in KLRG1 hiIL-7α-short-lived effector cells(SLEC),indicating TCF-1 may has a highly effect on KLRG1loIL-7α+ memory precursors. These results suggested that TCF-1 may plays a pivotal role in both CD4+ and CD8+T subsets during malaria infection.