支气管哮喘是一种由T、B淋巴细胞等多种炎症细胞和介质参与的一种慢性气道炎症性疾患，发病机制尚不明确。业已表明，许多疾患中存在CD4+OX40+T细胞的高表达，OX40/OX40L信号在其发病中扮演重要角色，而在哮喘中该方面的研究不多。我们的前期研究发现，哮喘患者外周血存在CD4+OX40+T细胞增多和sOX40L含量的增加，并且和肺功能存在负相关关系。我们推测OX40/OX40L信号及其介导的CD4+OX40+T细胞在哮喘发病中可能具有重要地位。因此，本项目以CD4+OX40+T细胞和OX40/OX40L信号为切入点，通过建立急性哮喘动物模型，运用免疫组化、流式细胞术、ELISA、Western等方法，阐明CD4+OX40+T细胞活化及与其他免疫细胞的相互作用，探讨OX40/OX40L信号通路及其介导的CD4+OX40+T细胞在哮喘发病机制中的作用，以期为哮喘的临床治疗提供新的思路及靶点。

Bronchial asthma is a chronic airway inflammatory disease involving many inflammatory cells, inflammatory mediators and cytokines, and the pathogenesis is not completely clear. Many studies showed that the expression of OX40 on CD4+T cells was upregulated, and OX40/OX40L costimulatory signal played a very important role in the pathogenesis of many autoimmune diseases and disorders, but the precise mechanism needed further research. There was little research about CD4+OX40+ T cells in the pathogenesis of bronchial asthma. Our previous study found that the expression of OX40 on CD4+T cells was upregulated, and the concentration of sOX40L was increased in asthma patients. Also the concentration of sOX40L was negatively correlated with pulmonary function indexes in acute asthmatic patients group. We hypothesized that OX40/OX40L costimulatory signal pathway and the CD4+OX40+ T cells mediated by the signal might play an important role in the pathogenesis of asthma. Therefore, through establishing a murine model of acute asthma, and applying the methods of immunohistochemistry, flow cytometry, ELISA, Western Blot, immune cell function assay and animal model to clarify the effects and mechanisms of OX40/OX40L costimulatory signal on the activation of CD4+OX40+ T cells and the interactions with other immune cells, which probe the role of OX40/OX40L costimulatory signal pathway and the CD4+OX40+ T cells mediated by the signal in the pathogenesis of asthma. Through this model we hope for finding some new ideas and targets for the treatment of asthma.