Effect of bacillus calmette-guerin treatment on airway inflammation and T regulatory cells in mice with asthma / 中国当代儿科杂志

ABSTRACT

<p><b>OBJECTIVE</b>Previous studies have shown that bacillus calmette-guerin (BCG) can deviate TH2 response toward TH1 response, resulting in a suppressive effect on the development of asthma/atopy. This study examined the effect of BCG treatment on regulatory T cells in asthmatic mice to investigate the possible mechanism.</p><p><b>METHODS</b>Kunming mice were sensitized and challenged with ovalbumin (OVA) to establish asthmatic models. Asthmatic mice were injected intradermally with BCG five days before and after sensitization. After 24 hrs of last challenge, bronchoaveolar lavage fluid (BALF) and peripheral blood were collected . The total cells and eosinophils were counted in the BALF. The percentage of CD4(+) CD25(+) in peripheral blood was detected with flow cytometry. Single spleen cell suspension was prepared and cultured in 1640 medium for 48 hrs and then the cytokine IL-10 level in the supernatant was determined using ELISA. The mice which were challenged with normal saline were used as the Normal control group.</p><p><b>RESULTS</b>The number of total cells and eosinophils in BALF in asthmatic mice [(27.27 +/- 5.36) x 10(7)/L and (6.59 +/- 1.32) x 10(7)/L respectively] were more than in the Normal control group [(1.52 +/- 0.36) x 10(7)/L and zero respectively] (P < 0.01). The number of total cells and eosinophils in BALF in asthmatic mice were reduced after BCG treatment [(13.71 +/- 3.17) x 10(7)/L and (1.43 +/- 0.37) x 10(7)/L respectively] (P < 0.01). The percentage of CD4(+) CD25(+) in peripheral blood of asthmatic mice [(11.59 +/- 1.33)%] was noticeably lower than that of the Control group [(13.66 +/- 1.68)%] (P < 0.01), but increased significantly in asthmatic mice after BCG treatment [(14.40 +/- 2.70)%] (P < 0.05). The IL-10 level in spleen cell supernatant in the BCG-treated group (7.79 +/- 1.34 pg/mL) also increased compared with that in the untreated asthmatic mice (5.54 +/- 0.66 pg/mL) (P < 0.01).</p><p><b>CONCLUSIONS</b>BCG can markedly inhibit the airway inflammation in asthmatic mice possibly by promoting the production of regulatory T cells.</p>