Suppressive effects of Tripterygium wilfordii Hook f., a traditional Chinese medicine, on collagen arthritis in mice.

The effect of chloroform extract of Tripterygium wilfordii Hook f. (TWH extract), a traditional immunosuppressive Chinese herb, on type II collagen (C II)-induced arthritis (CIA) in DBA/1J mice was studied. In the first set of experiments, we examined the effect of TWH extract on cellular immune responses to C II. As compared with mice treated with saline, TWH extract administered orally at doses of more than 400 microg kg(-1) once a day for 14 days inhibited the ability of inguinal lymph node cells to produce T cell cytokines interleukin-2 and interferon-gamma when the cells were obtained from mice 21 days after immunization and cultured in vitro with C II. Treatment with TWH extract also inhibited production of macrophage cytokines interleukin-1beta and tumor necrosis factor-alpha in response to in vitro stimulation of lymph node cells with C II. In the second part of the experiment, we evaluated the influence of TWH extract on the incidence and development of arthritis in murine CIA. Mice were immunized twice at a 3-week interval with bovine C II, with TWH extract being given orally once a day for 14 days with four different regimens. A 14-day course of TWH extract treatment at a daily dose of 400 microg kg(-1), which began on the day of the first C II immunization, suppressed the development of arthritis, as well as antibody production and delayed-type hypersensitivity to C II. Treatment with TWH extract, which started on the same day as the booster immunization, also resulted in inhibition of development of arthritis and of immune responses to C II. On the other hand, therapeutic administration with TWH extract did not affect the clinical course of the disease and the immune response to C II.