Effects of triptolide on T lymphocyte functions in mice

Triptolide (Tri) is an active principle of Tripterygium hypoglaucum Hutch, which has been used to treat cancers and autoimmune diseases in folk medicine. The lymphocyte proliferation (LP) induced by Con A or Lipopolysaccharide (LPS) was suppressed by Tri at 50 and 500 ng/ml. At 5 ng/ml the suppressive effect on LP induced by Con A was much stronger than that by LPS. The humoral immune reaction monitored by quantitative hemolysis spectrophotometry (QHS) was suppressed by Tri 0.75 and 1 mg/kg ip. IL-2 production by mouse spleen cells were suppressed by Tri 5, 50,500 ng/ml in vitro and 0.5, 0.75 and 1 mg/kg ip. IL-2 activity was assayed by assessing its ability to support proliferation of selected IL-2-dependent T cell line, measured by colorimetric method which is based on the ability of viable cells to cleave MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide). Ts cells induced by supraoptimal immune (SOI) were suppressed by Tri 0.5 and 0.75 mg/kg ip. These results suggest T or its subpopulations and B lymphocytes may be the target cells of Tri.