肺炎支原体感染对BALB／c小鼠肺泡灌洗液中干扰素-γ白细胞介素-4及白细胞介素-5含量的影响

The levels of interferon-v, interleukin-4 and interleukin-5 in bronchoalveolar lavage fluid of BALB/c mice infected by Mycoplasma pneumonia

目的探讨肺炎支原体（Mycoplasmapneumonia，MP）感染对小鼠肺泡灌洗液（bronchoalveolar lavagefluid，BALF）中干扰素（interferon，IFN）-γ、白细胞介素（interleukin，IL）-4及IL-5含量的影响，研究MP感染是否通过对Th1／Th2免疫应答的影响参与哮喘发病机制。方法按照随机分组的原则将40只BALB／c小鼠分为正常对照组20只，MP感染组20只；MP感染组分别于MP感染第3、7、14、21天取BALF，每次5只。采用ELISA方法检测小鼠BALF中IFN-γ、IL-4及IL-5的含量。结果MP感染组的BALF中IFN-γ、IL4及IL-5含量较正常对蜩组显著升高，差异有统计学意义（P〈0．05）。在MP感染第7天小鼠BALF中IFN-γ、IL4及IL-5含量达到高峰。MP感染组小鼠BALF中IFN-γ/IL-4比值较正常对照组降低，且在第7天达到低谷，差异有统计学意义（P〈0．05）。结论MP感染可使小鼠BALF中IFN-1、几4及IL-5含量升高，且在第7天达到最高峰，MP感染可以增加Th1、Th2细胞因子的释放，诱导Th1向Th2的免疫应答失衡，且可能通过此途径参与哮喘气道炎症的形成。

Objective To investigate the influence of Mycoplasma pneumonia （MP） on the levels of interferon （IFN） -γ, interleukin （IL） -4 and IL-5 in bronchoalveolar lavage fluid （ BALF ） of BALB/c mice infected by MP, and to study whether MP infection may be involved in the pathogenesis of asthma through the pathway of influencing T helper type 1 （ Thl ）/T helper type 2 （Th2） immune response. Methods Forty BALB/c mice were randomly divided into two groups, control group and MP infected group, each group 20 mice. The BALF of MP infected group was respectively collected after MP infection at 3,7,14,21 days, each time 5 mice. The levels of IFN-γ, IL-4 and IL-5 were detected by enzyme linked immunosorbent assay. Results The levels of IFN-γ,IL-4 and IL-5 increased in MP infected group compared with control group, the differences were significant respectively （ P 〈 0. 05 ）. The levels of IFN-γ, IL-4 and IL-5 reached the peak at 7 d after MP infection. The IFN-γ/IL-4 ratio was significantly lower in MP infected group than control group, and achieved the trough at 7 d, the difference was significant （ P 〈 0. 05 ）. Conclusion MP infection can lead to the increased level of IFN-γ, IL-4 and IL-5 in BALF of BALB/c mice, peaked at 7 d. MP infection can increase the discharging of Thl cytokines and Th2 cytokines,induce Thl/Th2 immune response disequilibrium,and it may be involved in the pathogenesis of asthmatic airway inflamation through the pathway.