Upregulation of CD80 (B7-1), CD86 (B7-2) and MHC class II expression and induction of IL-12 production by CD40 triggering of bone marrow-derived DCs. BM-derived DCs collected after 7 days of culture with GM-CSF were cocultured for 4 days in GM-CSF either with CD40L-transfected 3T3 cells or with untransfected 3T3 cells. These cells were then processed for double staining using anti-CD11c (N418) mAbs followed by anti-B7-1, anti-B7-2 or anti-MHC class II mAbs. (A) Staining of the different mAbs on CD11c+ cells. (B) BM-derived DCs collected after 7 days of culture in the presence of GM-CSF were exposed to the indicated stimuli for 48 hours with GM-CSF and IL-12 p70 heterodimer production was determined by ELISA. Each value is the mean of 3 different experiments.