To confirm extracts of activity from Traditional Chinese Medicine TongBiHeJi,  study effect on two signaling pathways of T cells and clarify the pharmacological mechanisms of TongBiHeJi.
Concanavalin(ConA) were added successively into rats lymphocytic culture with different extracts of activity from Traditional Chinese Medicine. After 24 hours,  CD71 expression rate on rat T lymphocytes activated with ConA was analyzed by flow cytometry. TCR,  CD28 and ICOS on T cells were detected after T lymphocytes of rat activated by ConA were cultivated with various EthylAcetate extraction of TongBiHeJi(TBHJ) and Methotrexate (MTX) for 48 hours.
CD71 expression rate on rat T lymphocytes induced by ConA was increased to 69.7%. TBHJ inhibited   the rate of CD3(+);CD71(+); expression(32.5%); ConA up-regulated TCR,  CD28 and ICOS expression on T cells obviously. There was different between ConA and positive control significantly(P<0.001). TBHJ could down-regulate obviously TCR, CD28 and ICOS expression on ConA-activated T lymphocytes with Concentration-dependent, especially ICOS. MTX inhibited CD3(+);CD71(+); and CD3(+);TCR(+); expression also.
TBHJ  inhibited T cells activation by adjusting two signaling pathways. That implied TBHJ could block CD28-ICOS signaling molecules to induce immunological tolerance. This study provided an experimental basis for application of TongBiHeJi to treatment of rheumatoid arthritis.