rGM-CSF/rIL-4 increased the expression of MHC class I, whereas rGM-CSF and rGM-CSF/IL-4 increased the expression of MHC class II on splenic DCs.

Mice were treated with rGM-CSF (GM) or the combination of rGM-CSF/rIL-4 (GM/IL-4), as described for Figure 1. Spleen cells were stained with fluorescent mAb to CD11c and CD8α (lymphoid DCs) or CD11c and CD11b (myeloid DCs) and were examined for the expression of MHC class I (A) or MHC class II (B). Only GM/IL-4 significantly increased the expression of MHC class I on lymphoid and myeloid DC subsets. In contrast, both GM and GM/IL-4 significantly increased the expression of MHC class II, with the highest expression on cells from mice treated with GM/IL-4. Data from a representative experiment (n = 5). *P ≤ .05 compared with control; †P ≤ .05 compared with GM. □ indicates control; , GM; ■, GM/IL-4.