IFN-γ在沙眼衣原体呼吸道感染中免疫防御机制的探讨  

The immune defence mechanism of IFN-γ following Chlamydia trachomatis lung infection

作　　者：布晓坤[1] 李宏钊[1] 邢冬红[1] 黄焕军[1] 白虹[1] 

机构地区：[1]天津医科大学免疫学教研室,天津300070

出　　处：《中国免疫学杂志》2007年第12期1129-1132,共4页Chinese Journal of Immunology

基　　金：天津市自然科学基金资助(07JCYBJC10600)

摘　　要：目的:检测与IFN-γ作用相关的酶吲哚胺2,3二氧化酶(IDO)、诱导性一氧化氮合成酶(iNOS)和NADPH氧化酶(ox)gp91在沙眼衣原体呼吸道感染中的表达及与机体防御的关系,探讨衣原体感染中IFN-γ免疫防御作用的机制。方法:用沙眼衣原体小鼠肺炎株(MoPn)通过鼻腔感染C57BL/6(H-2b)小鼠,用过氧化物酶连接的鼠抗衣原体脂多糖单抗染色HeLa229细胞,检测衣原体在肺组织的生长;用RT-PCR检测衣原体感染后第7及14天小鼠肺组织IFN-γ、IDO、iNOS和gp91 NADPHox mRNA表达。结果:MoPn呼吸道感染后小鼠肺组织匀浆衣原体活性测定,于感染后第2天,HeLa229细胞内可见有衣原体包涵体生长,IFU值增高,于感染后第7天IFU达最高水平,以后逐渐下降,至感染后21天基本恢复到基线水平。与未感染的对照组比较,Th1细胞因子IFN-γ于感染后第7天表达显著增高,感染后14天有所降低,但仍维持较高水平;同时衣原体感染可显著诱导与IFN-γ作用相关的三种酶IDO、iNOS和gp91 NADPHox在小鼠肺组织的表达,感染后第7及14天,IDO,iNOS及gp91 NADPHox的表达与对照组比较均有显著差异,其中IDO和gp91 NADPHox于感染后第7天mRNA表达增高显著(P<0.01),14天略有下降(P<0.05)。结论:衣原体呼吸道感染诱导Th1细胞因子IFN-γmRNA高表达,参与宿主对衣原体的清除及机体免疫防御,此作用可能与其相应的酶IDO、iNOS和gp91NADPHox表达增高有关。Objective:To detect the expression of IDO, iNOS, gp91 NADPH ox releated with IFN-γ function following Chlamydia trachomatis lung infection in mice and to investigate the immunological defense mechanism of IFN-γ. Methods:A murine model of pneumonia induced by intranasal inoculation of Chlamydia trachomatis,mouse pneumonitis (MoPn) biovar,was used for this study. Chlamydial growth in the lung was assessed by inoculating HeLa 229 cell monolayer with lung homogenates followed by HRP conjugate anti-Chlamydial LPS mAb.The mRNA expressions of IDO, iNOS, gp91 NADPH ox and IFN-γ in the lung were determined by RT-PCR on day 7 and 14 postinfection.Results:Chlamydial growth in the lung was observed on day 2 postinfection, peaking at day 7 with subsequent decline in quantity. At day 21 following inoculation, the IFU declined to the baseline. Contrast with the uninfected group, Th1-like cytokine IFN-γ underwent a significant increase at day 7 and a decrease on day 14 postinfection. mRNA expression for IDO, iNOS, gp91 NADPH ox was significantly increased in the lungs on day 7 and 14 postinfection, IDO and gp91 mRNA expression was significantly highler at day 7(P<0.01) and started to decrease at day 14(P<0.05).The peak of IDO, iNOS, gp91 NADPH ox mRNA expression was correlated with IFN-γ (day 7 postinfection).Conclusion:Chlamydia trachomatis infection induces higher IFN-γ mRNA expression in the lung of the mice, which may contribute to anti-Chlamydia immune defence. This immunological defense mechanism may correlate with the increase express of IDO, iNOS and gp91 NADPH ox in the lung of the mice.

关 键 词：沙眼衣原体 IFN-Γ IDO INOS gp91 NADPH OX 

分 类 号：R374.1[医药卫生—病原生物学]