Fluorescence-activated cell sorting-based quantitation of T cell receptor restimulation-induced cell death in activated, primary human T cells.

After initial stimulation with antigen and exposure to the growth cytokine interleukin-2, activated T lymphocytes become sensitized to apoptosis upon antigen restimulation through the T cell receptor. This self-regulatory, restimulation-induced cell death (RICD) program constrains the proliferative capacity of activated T cells to help prevent excessive T cell accumulation and associated immunopathology. Here we describe a simple FACS-based approach for measuring RICD sensitivity in activated human T cells following polyclonal restimulation in vitro. This procedure is a straightforward research and clinical diagnostic tool for assessing RICD sensitivity for T cells derived from normal donors and patients suffering from diseases causing dysregulated T cell homeostasis.