日本血吸虫感染小鼠肺脏中T细胞的功能特点及TLR3表达

Immunological characteristics and TLR3 expression of T cells in the lung of C57BL/6 mice after Schistosoma japonicum infection

目的探讨日本血吸虫感染后小鼠肺脏T细胞含量及功能的变化情况。方法日本血吸虫感染C57BL/6小鼠5~6周后,分离肺脏,制备石蜡切片,HE染色观察病理改变,同时获取单细胞悬液,流式细胞术检测T细胞的含量;使用细胞表面染色的方法观察T细胞在感染后CD25、CD69、CD62L、CD127表达情况;经PMA和离子霉素的刺激,使用细胞内染色的方法检测IFN-γ、IL-4、IL-5、IL-10的分泌情况,同时观察T细胞表达TLR2和TLR3的变化情况。结果日本血吸虫感染小鼠后,观察到肺部中肉芽肿的存在,肺脏中T细胞百分比含量显著增加(P<0.01);感染组CD69在T细胞上的表达比例达显著高于正常组(P<0.01),而感染组T细胞CD62L和CD127分子表达较正常对照组显著下降(P<0.05,P<0.01);感染后,T细胞分泌IFN-γ、IL-4、IL-5和IL-10的水平较正常组显著增加(P<0.05或P<0.01);感染后TLR3在T细胞表面上表达较正常对照组显著增加(P<0.01)。结论血吸虫感染5~6周后小鼠肺脏中T细胞为一群表型和功能独立的细胞群,且可能通过上调TLR3来发挥免疫调节作用。

This study was designed to explore the immunological characteristics and percentage of T cells in the lung of C57BL/6 mice after Schistosoma japonicum infection.C57BL/6 mice were infected by Schistosoma japonicum,and the lungs were isolated 5-6 weeks later and the lung sections were prepared and stained with haematoxylin and eosin to observe the histopathological changes.The single cell suspension solution was prepared,and the percentage of T cell was detected by flow cytometry.The expressions of CD25,CD69,CD62L and CD127 on the surface of T cells were observed by cell surface staining;the expressions of IFN-γ,IL-4,IL-5 and IL-10 on T cells were detected by intracellular cytokine staining after the stimulation with PMA plus ionomycin.Moreover,the expressions of TLR2 and TLR3 in T cell were observed.Data showed there was pulmonary granulomatous inflammation around schistosome eggs;the percentage of T cells in the lung form the infected mice was significantly higher than that in the control mice(P<0.01).FACs results showed that the proportion of CD69+cells in T lymphocytes of the infected group was significantly higher than that of control group(P<0.05);the percentages of CD62L and CD127 cells in T cells of the infected group were lower than those in the normal group(P<0.05 and P<0.01).The T cells expressed higher levels of IFN-γ(P<0.01),L-4(P<0.05),IL-5(P<0.01)and IL-10(P<0.05)in the infected mice.Moreover,the expression of TLR3 in T cells of infected mice was significantly higher than that in control mice(P<0.01).In conclusion,these findings suggested that the T cells in the lung infected with Schistosoma japonicum after 5-6 weeks is a population of phenotypically and functionally independent cells,which may up-regulate TLR3 in response to infection.