Abstract
T cells play a key role in adaptive immunity. Defects in specific T cell receptors or signaling proteins can alter their frequency and activation status, which may be associated with immune disease or cancer. Monitoring of T cell frequency and function in genetically modified mice or murine models of disease is therefore of high interest. Here, we provide a detailed protocol to analyze regulatory T cells, T cell activation, and cytokine production in thymus, spleen, or blood via flow cytometry. For complete details on the use and execution of this protocol, please refer to Demeyer et al. (2020).