Objective To explore the probable immune regulation mechanism of Feiliuping Extractum（ 肺瘤平膏） in treating tumor. Methods The Feiliuping Extractum was decomposed into Jiedu Recipe（ 解毒方）

Yiqi Recipe（ 益气方） and Yiqi Jiedu Recipe（ 益气解毒方）

and the medicated serums were prepared. The dynamic interaction between mature dendrite cells and T cells in vitro was observed by scanning electron microscope（ SEM） and laser scanning confocal microscope（ LSCM）. The dendrite cell culture was set as the blank group

while the tumor antigen loaded dendrite cells was divided into the load group

Jiedu group

Yiqi group

Yiqi Jiedu group

the whole recipe group and the low

medium and high dose of dexamethasone（ DX） group

and four concentration ratios（ 106/106

106/105

105/106

105/105

dendrite cell/ T cell） were set in each group. On the 2nd day of cell culture

Jiedu group

Yiqi group

Yiqi Jiedu group and the whole recipe group were given 1ml of corresponding medicated serum to the cell

and the low

medium and high dose of DX groups were given DX sodium phosphate injection with the concentration of 37. 5

75. 0 and 150. 0 mg / ml

and the blank group and the load group were added 1 ml of incomplete RPMI-1640 culture medium. On the 8th day of culture

the T cell number and the immune synapse number in each group were compared at the 3rd and 6th hour of mixed culture. Results At the 30 th minute of mixed culture of tumor antigen loaded dendrite cells and T cells

the immune synapse formation was observed. At the 3rd hour

T cells proliferated significantly. After 6 hours

along with the decease of immune synapses

the cell distribution tended to be even gradually. In the whole recipe group

the T cell number and immune synapse number at the 3rd and 6th hour were larger significantly than the other groups（ P < 0. 05）. In each drug administration group

the synapse number at the ratio of 106/106 was larger significantly than the other ratios（ P < 0. 01）. In each group

the synapse number at the 6th hour had no statistically significant difference from that at the 3rd hour in different ratios（ P > 0. 05）.Conclusion Feiliuping Extractum could regulate the formation of immune synapse and promote the stimulation of the tumor antigen loaded dendrite cells on the proliferation of T cells. The whole recipe performs better than the decomposed recipes.