Fig. 1.

Immunosuppressive drugs (ISD) did not alter T cell activation but did inhibit T cell proliferation. T cell activation with anti-CD3 monoclonal antibody (mAb)/anti-CD28 mAb for 24 h resulted in up-regulation of CD25 and CD69 (a). None of the ISD affected CD25 levels, whereas cyclosporin inhibited the expression of CD69. Drug concentrations were 1·0 ng/ml tacrolimus, 100 ng/ml cyclosporin, 100 ng/ml mycophenolic acid (MPA) and 8·0 ng/ml rapamycin. Data are expressed as percentage of cells expressing CD25 or CD69 compared to medium controls (dotted lines), n = 4 (b). Carboxyfluorescein succinimidyl ester (CFSE)-labelled T cells were activated with anti-CD3 mAb/anti-CD28 mAb for 3 days in the presence of ISD. Data from a representative experiment are shown. Similar results were obtained in three independent experiments (c). Percentage inhibition of the T cell proliferation index by ISD compared to medium controls (dotted lines) are depicted, n = 3 (d). Drug concentrations were: 0·3 ng/ml tacrolimus, 50 ng/ml cyclosporin, 100 ng/ml MPA and 4 ng/ml rapamycin. **P < 0·01.