初次及再次感染肺炎衣原体Icr小鼠局部的免疫反应

Local immune responses to Chlamydia pneumoniae after primary infection and reinfection in Icr mice

目的:肺炎衣原体(Cpn)是一种常见的人类呼吸道致病菌,感染多为持续或慢性感染,机体感染后可引起以细胞免疫(CMI)为主的免疫反应。文中使用Icr小鼠建立初次及再次感染Cpn的动物模型,研究小鼠肺部及脾脏在初次及再次感染Cpn后的炎症机制及CMI反应。方法:初次感染(PT)组鼻内接种Cpn 105IFU/只。再次感染(ST)组4周后重复接种同样剂量的Cpn。对照组接种PBS0.05ml/只。在预设时间点处死小鼠后取肺及脾,分离出肺单核细胞及脾的淋巴细胞。用Cpn刺激,体外培养3 d。MTT法测定细胞增殖指数;ELISA法测定IL-4、IL-10、IFN-γ。结果:体外CMI显示用Cpn刺激后在PT组小鼠肺中出现一个较弱的增殖反应,并无IFN-γ的分泌。在ST组的肺及脾中则均引起以IFN-γ为主的细胞因子的分泌(P<0.01)。IL-4在2组小鼠肺中的测定基本为0。IL-10在PT组肺中无表达,在ST组中稍有升高,平均为0.4 ng/ml。在ST组脾中IL-4及IL-10均在35 d后有升高趋势,与PT组比较均有显著性差异(P<0.05)。结论:Th1型CMI引起的IFN-γ产生和淋巴反应增加是再次感染的特征。

Objective： Chlamydia pneumoniae is a kind of common pathogenic bacteria in respiratory passage which cause persistent and chronic infection cell mediated immunity results mainly followiny the infection.The infection kinetics and local in vitro-restimulated cell mediated immunity（CMI） responses in the lungs and spleens of Icr mice during Chlamydia pneumoniae（Cpn） primary infection and reinfection will be analyzed in this article.Methods： Icr mice were inoculated intranasally with 105 IFU of Cpn（PT group）.The same dose was given in the same way as rechallenge 4 weeks after the primary challenge（ST group）.Control groups were inoculated with 0.05 ml PBS.The mice were sacrificed at predetermined days,and the pulmonary mononuclear cells and splenic lymphocytes were isolated and stimulated with Cpn in vitro for 3 days.The proliferative response was measured by MTT;IL-4,IL-10 and IFN-γ were detected by ELISA.Results： The PT group showed a weak proliferative response and no secretion of IFN-γ in the lungs after Cpn stimulation,while the ST group presented a reinfection characterized by IFN-γ production both in the lungs and in the spleens（P〈0.01）.IL-4 secretion was not detected in either of the groups.The expression of IL-10 was absent in the lungs of the PT group and slightly elevated（mean 0.4 ng/ml） in the ST group.An increased secretion of IL-4 and IL-10 was observed in the spleens of the ST group at 35 days,with significant difference from the SP group（P〈0.05）.Conclusion： Reinfection with Cpn may induce Th1-biased（IFN-γ） CMI.