Chimeric receptors stimulate calcium mobilization.

4G4 T cells were loaded with the calcium sensitive fluorochrome, indo-1, stained with H-2K^b–specific antibody at 4°C, warmed to 37°C, and stimulated by antibody crosslinking with goat antimouse IgG at the timepoint indicated by the arrow. Changes in intracellular calcium were monitored by flow cytometry. Graphs represent calcium mobilization as a function of time. Addition of ionomycin resulted in marked calcium fluxes in all cell lines (data not shown). Data are representative of 2 experiments.