Costimulatory molecules and inhibitory FcγRIIb are not involved in the inhibition of OVA-IC presentation. (A) The cell-surface expression of MHC II, CD80, and CD86 was measured on BMDCs cultured for 48 hours in the presence or absence of IVIg (10 mg/mL). The MFIs are indicated in the upper right corner of the histograms. (B) BMDCs from wild-type or fcgr2b^−/− BALB/c mice were used in the OVA-IC antigen presentation assay done with DO-11.10 cells in the presence (■) or absence (□) of IVIg (10 mg/mL). The results are expressed as the percentage of the amount of IL-2 secreted in the presence of IVIg compared with the control condition in the absence of IVIg. Results shown are representative of 2 independent experiments. *P < .001.