调节性B细胞对矽肺小鼠纤维化Th免疫应答的影响

Objective] To observe the effect of regulatory B cells (Bregs) on Th immune responses in silica-induced lung fibrosis in mice. [Methods] Healthy adult female C57BL/6 mice were divided into 3 groups: control group, silicosis group and Bregs depletion group. To setup the silicosis model, mice in silicosis group and Bregs depletion group received 3mg/50μl silica suspension intratracheally. To deplete Bregs, mice in Bregs depletion group were injected intraperitoneally with 300 μg anti-CD22 Abone day before the silica exposure. Mice were sacrificed at 7, 28 or 56 days after silica exposure. Bronchoalveolar lavage fluid and lung tissues were obtained. The hydroxyproline content in mice lungs and the secretions of cytokines IL-2 and IL-13 were examined. [Results] The hydroxyproline content of lung in Bregs depletion mice decreased obviously at day 56 after silica exposure compared with that in silicosis group (p<0.05). The secretion of IL-2 in Bregs depletion mice increased significantly at day 28 after silica exposure compared with that in control group and silicosis group (p<0.05). The secretion of IL-13 in Bregs depletion mice decreased significantly at day 56 after silica exposure compared with that in silicosis group (p<0.05). [Conclusion] Bregs promoted the collagen deposition in mice lung through affecting Th1/Th2 immune balance.