Syt7 or MAL silencing inhibit T cell activation. Primary CD4 T cells transfected with siRNA Syt7 (siSyt7), siRNA MAL (siMAL), or siRNA control (siCTR) were activated with superantigen-pulsed Raji cells for 10 min (A), 4 h (B), or 16 h (C–G). MAL-silenced cells were antigen-stimulated in the absence (siMAL) or in the presence of thapsigargin (siMAL TPS) or ionomycin (siMAL Iono). Calcium ionophore and phorbol myristate acetate (PMA-iono) were added as positive control (D, F, and G). Cells were analyzed by flow cytometry. (A) Erk activation by CD4 T cells determined by intracellular staining gated on CD4⁺ cells. (B) Frequency of CD69⁺CD3⁺ T cells determined by surface staining. (C–F) IL-2 and IFN-γ production by CD4 T cells was determined by intracellular cytokine staining gated on CD4⁺ cells. (G) Number of IFN-γ–secreting cells revealed by ELISPOT, each open circle represents an individual experiment. Images representative of three experiments.