卡介苗预防哮喘大鼠模型形成及其与γδT细胞关系的研究

An experimental study of the effect of bacille almette-guerin vaccine on the production of a rat asthmatic model and its relation withγδT cells

目的 探讨卡介苗 (BCG)对哮喘的预防作用及其与γδT细胞的关系。方法 Wistar大鼠 4 0只 ,随机分为 4组 ,每组 10只 ,用“冻干皮内注射用卡介苗”给大鼠皮内注射 ,8周后应用鸡卵清蛋白 (OVA)致敏并雾化吸入刺激 ,制作致敏大鼠模型 ;测定气道反应性变化 ,并收集外周血单个核细胞 (PBMC)和支气管肺泡灌洗液 (BALF) ;采用流式细胞仪检测γδT细胞抗原受体 (γδTCR)和αβTCR阳性T细胞百分率及CD2 8/γδTCR平均荧光密度比 ,并用免疫荧光法结合HE染色以及免疫组化法检测γδT细胞占淋巴细胞的百分率。结果 常规哮喘模型组 (D组 )BALF中可见大量嗜酸细胞[EOS ,(2 5± 1 1)× 10 8/L],与正常对照组 (A组 ) [(0 0 )× 10 8/L]比较 ,差异有显著性 (P <0 0 1) ;D组5 0 %时乙酰甲胆碱 [PC50 ,(0 2 8± 0 10 )g/L]与A组 [(1 36± 0 76 )g/L]比较 ,差异有显著性 (P <0 0 1) ;而BCG免疫后哮喘模型组 (C组 )BALF中很难见到EOS[(0 0 )× 10 8/L],与A组 [(0 0 )× 10 8/L]比较 ,差异无显著性 (P >0 0 5 ) ,而C组PC50 [(1 2 8± 0 77)g/L]与A组 [(1 36± 0 76 )g/L]比较 ,差异无显著性 (P >0 0 5 )。BALF中BCG免疫组 (B组 )γδT细胞 /T细胞为 (41 3± 6 0 ) % ,γδT细胞 /淋巴细胞为 (35 2± 3 3) %

Objective To explore the preventive effect of BCG vaccine on asthma attack in rats and its relation with γ δ T cells Methods Wistar rats ( n =10, for each group) were immunized with BCG vaccine After 8 weeks, the rats were sensitized and challenged with ovalbumin to establish an asthmatic model After 3 weeks, the airway responsiveness(PC 50 ) was determined The percentage of γ δ T cells or α β T cells among total T cells or total lymphocytes and the ratio of the mean fluorescence density of CD 28 /γ δ TCR of γ δ T cell subset in peripheral blood and BALF were detected by flow cytometry, immunofluorescence and immunohistochemistry Results In the rat asthmatic model, the number of BALF eosinophils was increased [(2 5±1 1)×10 8/L vs (0 0)×10 8/L],( P <0 01) while the PC 50 was decreased [(0 28±0 10) g/L vs (1 36±0 76) g/L], ( P <0 01) However,the results of the group immunized with BCG vaccine were same as the controls [EOS(0 0)×10 8/L vs (0 0)×10 8/L],( P >0 05) PC 50 [(1 28 ±0 77) g/L vs (1 36±0 76) g/L,( P >0 05)] In the asthmatic group,γ δ T cell/T cell was (32 4±2 6)%,and γ δ T cell/lymphocytes (28 6±2 4)% In the group immunized with BCG vaccine,γ δ T cell/T cell was (41 3±6 0)% and γ δ T cell/ lymphocytes (35 2±3 3)% In the asthmatic group immunized with BCG vaccine,γ δ T cell/T cell was (47 3±8 5)% and γ δ T cell/ lymphocytes (39 0±6 8)% In the control group,γ δ T cell/T cell was (27 3±0 8)% and γ δ T cell/ lymphocytes (21 8±1 9)%, (all P <0 01) The ratio of the mean fluorescence density of CD 28 /γ δ TCR of γ δ T cell subset (0 66±0 08,0 88±0 26,0 71±0 15 vs 0 53±0 06,(all P <0 01) were increased Conclusions BCG vaccine was shown to be able to prevent the production of a rat asthmatic model γ δ T cells may also have a Th1/Th2 profile, and these cells may be important in the immunoregulation of BCG vaccine and the pathogenesis of asthma