Effect of IVIg on the in vitro antigen-specific T-cell activation. (A) OVA-specific DO-11.10 hybridoma cells were cultured for 24 hours with IFN-γ–stimulated P388D1 cells or BMDCs in the presence of absence of IVIg and OVA-IC. DO-11.10 cell activation was evaluated by measuring the IL-2 secretion using ELISA. (B) CD4⁺ T cells isolated from DO11.10 transgenic mice were stained with CFSE and cultured with IFN-γ–stimulated P388D1 cells or BMDCs in the presence or absence of IVIg (10 mg/mL) and OVA-ICs. Proliferation of OVA-specific CD4⁺ T cells was evaluated after 3 days, by flow cytometric analysis of CFSE dilution. The percentage of proliferating CD4⁺ T cells is shown in the upper left quadrant. Results are representative of 3 independent experiments. *P < .001; **P < .01; ***P < .05.