Figure 4.

FcγR-induced inhibition of IL-10 signaling requires activation of macrophages with IFN-γ. (A) Macrophages were cultured with M-CSF or IFN-γ for 2 d, Es or E-IgGs were added for 1 h, and STAT activation was measured after a 10 min stimulation with IL-10 (20 ng/ml) using immunoblotting. C, no erythrocytes were added. (B) FcγRs were ligated for one hour using plate-bound IgG, and STAT activation was measured using immunoblotting. (C) Macrophages cultured with M-CSF or IFN-γ for 2 d were analyzed using flow cytometry. (D) Individual FcγRs were cross-linked on IFN-γ–activated macrophages using specific F(ab′)s followed by F(ab′)₂ anti–mouse IgG, and STAT activation was measured using EMSA and immunoblotting.