Calcium mobilization induced after CD3, CD148, and CD3+CD148 crosslinking. Peripheral blood lymphocytes were loaded with fura-2, and [Ca²⁺]_i was measured as described in the Materials and Methods. Cells were incubated 30 minutes at 4°C with the different MoAbs (CD3, 10 μg/mL; 143-41, 50 μg/mL; CD45, 50 μg/mL) and adhered to Cell-Tak coated coverslips. After establishing baseline values, a saturating amount of GAM was added to prewarmed samples (arrow). [Ca²⁺]_iwas measured every 5 seconds for 15 minutes on a single-cell basis in a computer-aided fluorescence imaging. The average curve of a minimum of 200 individual cells for each condition of at least four independent experiments are shown. Calcium changes are expressed as the percentage change from basal.