Objective: To investigate the effect of Yupingfeng San on the immune function of mice models with lung injury induced by smoked soot-related respirable particulate. Method: The experimental mice were placed in a special exposure box

and the smoke from the combustion of coal was introduced into the box. The PM 2.5 concentration in the box was maintained at 700-900 μg · m-3 to establish the model of lung injury. The Yupingfeng San decoction was given to the models by intragastric administration in 3 different ways:prevention

prevention+treatment

and treatment. Then the proportion of dust cells in the alveolar lavage fluid was detected; the count of CD68+ macrophages in the lung tissues was detected by immunocytochemistry; CD4+ and CD8+ cells counts and their ratio were detected by flow cytometry; IgE and IgG concentrations in serum and lung tissues were detected by enzyme-linked immunosorbent assay (ELISA). Result: The dust cells count and CD68+ macrophages count in alveolar lavage fluid of model mice were increased significantly; serum CD4+

CD8+ were decreased; the IgE level in serum was increased and the IgG level in serum was decreased; IgE level in the lung homogenate had no obvious change

while the IgG level in lung homogenate was decreased significantly in model group. After drug intervention

the count of CD4+ and CD8+ cells in the blood was increased

but there was no statistical difference between the two groups. The count of dust cells and the count of CD68+ macrophages were decreased significantly

most obvious in the prevention+treatment group. The IgE level in serum was lowest in the prevention group

and the IgG level in serum and lung homogenate was highest in the prevention+treatment group. Conclusion: Yupingfeng San can improve the cellular and humoral immune function of mice

and the effect can be maintained in toxic environment; however the effect in the toxic environment is far less than the earlier application effect.