Abstract
Antigen recognition and activation of T cell receptor (TCR) triggers transient calcium release from intracellular compartments and subsequent sustained calcium influx through cell surface Icrac channels. Sustained elevation of the cytoplasmic calcium level activates many calcium-dependent enzymes and transcription factors, which are essential for T cell activation and function. This protocol uses non-ratiometric dyes, in combination with flow cytometry, to monitor TCR-triggered calcium changes over time, and is a simple assay to examine the existence of T cell calcium mobilization defects in transgenic mice.