IL-33缺陷调节小鼠抗弓形虫感染的CD8^(+)T细胞应答

IL-33 deficiency regulates the CD8^(+)T cell response in mice with Toxoplasma gondii infection

目的探讨IL-33缺陷(IL-33^(-/-))对弓形虫感染小鼠的炎症反应和CD8^(+)T细胞功能的影响。方法C57BL/6野生型(Wild-type,WT)和IL-33^(-/-)小鼠分别设感染组和对照组,建立弓形虫感染模型,记录小鼠死亡时间,绘制生存曲线;分别取感染后48 h、96 h各组小鼠外周血及肝、脾组织,HE染色观察组织病理变化;微量样本多指标流式蛋白定量技术(cytometric bead array,CBA)及ELISA检测血浆炎症因子(IL-12P70、TNF-α、IFN-γ、MCP-1、IL-6及IL-4)水平;qPCR检测小鼠脾细胞中弓形虫速殖子表面抗原-1(SAG-1)的mRNA水平;流式细胞术分析脾脏CD8^(+)T细胞穿孔素、颗粒酶和IFN-γ水平。结果与WT感染组小鼠比较,96 h时IL-33^(-/-)感染组小鼠脾脏SAG-1 mRNA表达降低(F=13.96,P<0.05),肝、脾组织的炎症改变较轻,生存时间延长(χ^(2)=6.87,P<0.01);与WT感染组小鼠比较,感染96 h时IL-33^(-/-)感染组血浆IL-4浓度升高较高(F=328.32,P<0.01),而TNF-α、IFN-γ、MCP-1均明显较低(F TNF-α=32.66、F IFN-γ=59.32、F MCP-1=43.78,均P<0.01);感染96 h,IL-33^(-/-)感染组小鼠脾脏CD8^(+)T细胞穿孔素(F=574.20,P<0.01)、颗粒酶(F=14.68,P<0.05)和IFN-γ(F=15.22,P<0.05)表达均高于WT感染组。结论在小鼠急性弓形虫感染中,IL-33抑制脾脏CD8^(+)T细胞应答,促进全身炎症反应。

We investigated the effect of IL-33 deficiency(IL-33^(-/-))on inflammatory and CD8^(+)cytotoxic T cell responses against Toxoplasma gondii infection in mice.Wild-type(WT)C57BL/6 and IL-33^(-/-)mice were divided into two groups:T.gondii-infected and control.The survival rates were determined in the two groups.The pathologic changes in the liver and spleen were checked by HE staining.Plasma cytokines(IL-12P70,TNF-α,IFN-γ,MCP-1,IL-6,and IL-4)were measured by CBA and ELISA.The level of Toxoplasma gondii surface antigen-1(SAG-1)mRNA in the spleen was detected by fluorescence quantitative PCR.The intracellular cytokine,IFN-γ,perforin,and granzyme B in CD8^(+)T cells were analyzed by flow cytometry.The data showed that the 96-h survival rate were increased,less inflammation occurred in the liver and spleen,and increased plasma proinflammatory cytokines were attenuated in IL-33^(-/-)mice compared with WT-infected mice.In addition,upregulation of perforin,granzyme B,and IFN-γfrom CD8^(+)T cells in the spleen were observed with IL-33 deficiency 96 h post-infections.These results suggest that IL-33 promotes the inflammatory response and inhibits the cytotoxic function of CD8^(+)T cells in mice with acute T.gondii infection.