IFN-γ/IL-4–primed PCMCs can capture and process of protein antigen. (A-D) IFN-γ/IL-4–primed PCMCs were incubated for 16 hours with soluble OVA, OVA-IgG immune complexes (ICs), or soluble OVA in the presence of control rabbit IgG (ctrl rIgG) or OVAp. (A-B) Cells were cocultured with effector OT-II T cells for 16 hours, and CD69 up-regulation on OT-II T-cell surface was measured by FACS analysis on Vα2⁺ gated cells. (A) FACS profiles representative of 3 independent experiments. The numbers inside the panel indicate the percentage of positive cells. (B) Data are presented as percentage of Vα2⁺ gated cells up-regulating CD69 (mean ± SEM of 3 independent experiments). (C) Proliferation of T cells was monitored by carboxyfluorescein succinimidyl ester dilution after 72 hours of coculture. Panels show FACS profiles from 1 representative experiment of 3. (D) IFN-γ in supernatant was dosed by ELISA after 16 hours of coculture (mean ± SEM of 3 independent experiments). Difference between groups was evaluated by an unpaired Student t test with the GraphPad Prism software. It should be noted that DCs were more efficient than PCMCs in inducing functional responses to whole ovalbumin in OT-II T cells. Approximately 95% of T cells proliferated when cultured with DCs previously incubated with OVA (400 μg/mL) and approximately 85% of T cells proliferated when cultured with DCs previously incubated with IgG-OVA (30 μg/mL). IFN-γ production by OT-II T cells when cultured with DCs pulsed with OVA (400 μg/mL) or IgG-OVA (30 μg/mL) was approximately 50 ng/mL and approximately 10 ng/mL, respectively.