Inhibitory effects of CD1d+ pMφ on OVA-specific CD4+ T cell activation. pMφ from CD1d+/− and CD1d−/− mice were loaded with or without OVA protein, treated with TGF-β2 if necessary, and co-cultured for 72 h with CFSE-labeled CD4+ T cells from OVA-primed OT-II mice. (A) CFSE profiles of OT-II cell. Histogram shows CFSE profile of TCRVα2+ -gated cells; (B) Percentages of proliferating CD4+ T cells gated on TCRVα2+ cells; (C) Supernatants from cocultures were collected and levels of IFN-g were analyzed using ELISA. Data are representatives of four independent experiments. ***P < 0.001; **P < 0.01; *P < 0.05 (Student’s t-test).