Inhibition of class I MHC–restricted presentation of exogenous OVA by CsA and tacrolimus. Indicated amounts of CsA (○), tacrolimus (▿), or rapamycin (□) were added to cultures of DC2.4 cells (A) or BM-derived DCs (B) together with OVA microspheres (50 μg/mL). After 2 hours, unphagocytized OVA microspheres and immunosuppressive drugs were removed by washing, and then a cross-presentation assay was performed with B3Z cells as described in Figure 1A. Each data point represents the mean plus or minus the standard deviation (SD) of values obtained from 3 experiments.