[Experimental study on the immunosuppressive effects of qinghaosu and its derivative]

In this report the researches studied the immunosuppressive effects of Qinghaosu (QHS) and its derivative (DQHS). The results indicated that after 7-day successive administration i.p of QHS and DQHS at the dosage of 25-100 mg/kg, the amounts of anti-SRBC IgM PFC and IgG PFC in the murine spleen were decreased significantly (P less than 0.01). At the dosage of 100 mg/kg the QHS and DQHS were able to inhibit the DTH induced with BSA and the proliferative responses of murine spleen cells to Con A and LPS. These results suggested the suppressive effects of QHS and DQHS on both humoral and cellular immunities of mice. Interleukin-2 (IL-2) is an important mediate in the immune response and plays a critical role in the activation and differentiation of T and B lymphocytes. The results in this report showed a significant suppression of IL-2 production of murine spleen cells after 7-day administration i. p of QHS and DQHS, which suggested that the inhibition of IL-2 production could be the important one of the mechanisms of the immunosuppressive effects of QHS and DQHS.