MIR2 downregulation of CD1d lowers CD1d-restricted T cell activation. (A) BJAB cells stably transduced with either lacZ (gray bars) as a control or MIR2 (white bars) were cocultured with CD1d-restricted T cells. This coculture was done in the presence of α-GalCer to provide an activating ligand for the T cells. Each coculture was performed in triplicate. After 18 hours of coculture, each supernatant was assayed for IFN-γ release by ELISA. (B) As in A, coculture experiments were done with CD1d-restricted T cells and BJAB cells, this time either in the presence or absence of α-GalCer. Cocultures were done with α-GalCer lacZ (light gray bars), α-GalCer MIR2 (white bars), lacZ without α-GalCer (black bars), and MIR2 without α-GalCer (dark gray bars). After 18 hours, the supernatants were recovered, and the IFN-γ in each supernatant was assayed by ELISA. (C) As in A, coculture experiments were done with CD1d-restricted T cells and BJAB cells, either in the presence of mouse anti–MHC class I as a control (lacZ, dark gray bars; MIR2, white bars) or mouse anti-CD1d (lacZ, black bars; MIR2, light gray bars). After 18 hours, the supernatants were recovered, and the IFN-γ in each supernatant was assayed by ELISA. Results are shown as means ± SD.