Objective To investigate the immunological effect of PM2.5 on cytokine production in female Wistar rats.Methods Female Wistzr rats were given 0.3 mg,0.75 mg,2 mg,5 mg of PM2.5 per 0.5mL saline,respectively.Saline was used as the negative control.TNF-α and IL-6 levels in the branchoalveolar lavage were measured by ELISA,and mRNA expression leveIs in lung tissue were detected bv RT-PCR.Alveolar macrophages were collected for testing phogacytic function. Results Exposure to PM2.5 stimulated TNF-α production in a dose-dependent manner(P＜0.05),However,no statistically significant difference was found.No time-dependent change in TNF-α and IL-6 production Was found.TNF-α and IL-6 mRNA expressions were induced by PM2.5-exposure.The phagocytic rate(PR)was significantly decreased by PM2.5 treatment.Conclusion PM2.5 exposure increases inflammation response of the lung in a dose-dependent mauuer.Moreover,tissue injury induced by PM2.5 may be related to altered production of cytokines.PM2.5 may impair the phagocytic activity of alveolar macrophages.