肺炎链球菌减毒活疫苗SPY1激发小鼠巨噬细胞应答的免疫作用机制研究

Immune response of mouse macrophage induced by live attenuated pneumococcal vaccine SPY1 and the mechanism

目的探讨肺炎链球菌减毒活疫苗SPY1对巨噬细胞引起的天然免疫应答及机制。方法体外诱导培养小鼠骨髓来源的巨噬细胞(bone marrow derived macrophage,BMDM),SPY1作用巨噬细胞6 h和24 h后,分别用RT-PCR和ELISA检测细胞因子的表达情况;SPY1作用于野生小鼠以及TLR2、TLR4缺陷小鼠的BMDM 24 h后,ELISA检测TNF-α和IL-6的表达;Western blot检测各信号分子的磷酸化水平;MAPK、PI3K和NF-κB抑制剂处理后,检测细胞因子TNF-α和IL-6的表达变化。结果 SPY1作用巨噬细胞后可引起强烈的免疫应答,此过程不依赖于TLR2和TLR4。MAPK、PI3K和NF-κB信号通路参与调控SPY1引起的巨噬细胞天然免疫应答。结论肺炎链球菌减毒活疫苗SPY1通过MAPK、PI3K和NF-κB通路产生巨噬细胞天然免疫应答,这一过程不依赖于TLR2和TLR4。

In previous study,we found that Streptococcus pneumoniae live attenuated vaccine SPY1 could be used as a vaccine against Pneumococcus colonization in mice. However,the mechanism underlying remains unclear.In this study,we generated macrophages from bone marrow cells of mice,and investigated macrophage response by RT-PCR and ELISA. TLR2 and TLR4 mutant mice were adopted to determine their role in macrophage response induced by SPY1. MAPK,PI3 K and NF-κB activation were measured by western blot and which was further evidenced by associated inhibitor. Treatment of macrophages with SPY1 caused upregulation of inflammatory cytokines（like TNF-α and IL-6）,which was not mediated by TLR2 or TLR4. Mechanistically,SPY1-induced macrophage activation was shown to result in MAPK,PI3 K and NF-κB activation and drastically abrogated by relevant inhibitor. Taken together,SPY1 can induce strong innate immune response in macrophage through MAPK,PI3 K and NF-κB signal pathways,but not depend on TLR2 or TLR4.