γδT细胞与哮喘特异性致敏原皮下脱敏疗法的研究

The study of relation between γδT cells and desensitization of specific antige n in asthma

目的 探讨支气管哮喘γδT细胞与特异性致敏原脱敏疗法的关系 ,了解γδT细胞在哮喘发病机制中的作用。方法 应用卵清蛋白 (OVA)致敏并刺激Wistar大鼠 ,制作致敏大鼠哮喘模型 ;再用OVA皮下注射脱敏 ;观察脱敏前后OVA激发反应 ,测定气道反应性 (PC50 ) ;肺组织切片做HE染色观察炎症改变和做原位杂交检测IL 4mRNA和IFN γmRNA表达 ,并采用免疫组化法检测肺组织中γδT细胞数量 ;用ELISA法检测血清IL 4和IFN γ浓度 ,用流式细胞术检测PBMC和支气管肺泡灌洗液 (BALF)中γδTCR阳性T细胞百分率。结果 在脱敏组 (C组 ) ,用脱敏前激发浓度的OVA激发不再有明显哮喘发作 ,支气管肺内嗜酸细胞 (Eos)消失、过敏性炎症消除 ,其PC50 与对照组 (即D组和E组 )比较差异均有显著性 (均为P <0 .0 1)、而与正常组 (即A组 )比较差异无显著性 (P >0 .0 5 ) ;C组肺内IL 4mRNA表达及血清IL 4浓度均明显低于D、E组 (均为P <0 .0 1) ,而C组肺内IFN γmRNA表达及血清IFN γ浓度均明显高于A、D、E组 (均为P <0 .0 1) ;与此同时 ,C组肺组织内及BALF中γδT细胞数量则明显低于D、E组 (P <0 .0 1或P <0 .0 5 )。结论 特异性致敏原皮下脱敏疗法能纠正哮喘TH1 TH2反应失衡 ,同时伴随肺内及外周血γδT细胞异常分布的恢复 ,提示γδT?

Objective To explore the potential linkage betwe en γδT cells and desensitization of special antigen in asthma. To learn the ro le of γδT cells in asthma mechanisms. Methods Wistar ra ts ( n =10, for each group) were sensitized and challenged with OVA (ovalbumin ) to establish an asthmatic model. Then the animals were desensitized with OVA. The response to the challenge of OVA, HE staining of BALF cells and lung tissue and airway responsiveness (PC 50 ) were examined. The expression of IL-4 mR NA and IFN-γ mRNA was detected by in situ hybridization. The number of γδT c ells from lung tissue was determined by immunohistochemistry. The levels of IL- 4 and IFN-γ was assayed by ELISA. Flow cytometry was used to detected the perc entage of γδT cells of PBMC and BALF. Results In th e group desensitized with OVA (group C), the animals did not show any presentati on of asthma with OVA challenge. The allergic inflammation disappeared in lung t issue. The PC 50 in group C did not differ from that in normal control grou p but was higher than that in asthmatic control group (group D and E, P <0. 01). In group C, the lever of IL-4 in serum and expression of IL-4 mRNA in lu ng tissue significantly decreased ( P <0.01) while the lever of IFN-γ in serum and expression of IFN-γ mRNA in lung tissue significantly increased ( P <0.01). The counts of γδT cells significantly decreased ( P <0.01) in the BALF and lung tissues compared with those in asthmatic control groups (group D and E), but no difference was found between group C and control group. Conclusion The desensitization of special antigen is able to c orrect the unbalance of T H1/T H2 and abnormal distribution of γδT cell in a sthma at the same time. Our results suggeste that γδT cells are well related t o the desensitization of special antigen in asthma, and new cells as well as mol ecule mechanisms of desensitization of special antigen in asthma and have proved that γδT cells are important cells in mechanism of asthma.