CD2–CD58 interaction enhances T cell signaling. (A) To study TCR–CD2 dual-signaling system, bilayers were prepared containing GPI-linked CD58 and anti-TCR antibody linked to lipid via biotin-streptavidin conjugate (monobiotinylated antibody and biotinylated lipid were connected by streptavidin). (B and C) Calcium elevation (Fura-2 emission ratio, 340 nm/380 nm; B) and CD69 surface expression level (C) were measured in Jurkat cell interacting bilayers containing different amounts of anti-TCR (75, 300, and 600 molecules/µm²), CD58 (40 molecules/µm²), both CD58 and anti-TCR (40 and 75 molecules/µm², respectively), and ICAM-1 (10 molecules/µm²) after 3 h of cell–bilayer contact. Representative data for three independent experiments are shown. Measurements and quantifications were performed as described in Fig. 1 (data shown are mean ± SEM, n > 50).