The immunological synapse is a complex structure that decodes stimulatory signals into adapted lymphocyte responses. As such, it represents a unique window to monitor lymphocyte activity, owing to the development of systematic quantitative approaches applicable to primary cells. Here we demonstrate the applicability of high-content imaging to human T and NK cells and develop a pipeline for unbiased analysis of high-definition morphological profiles. Our approach reveals how distinct facets of actin cytoskeleton remodeling shape immunological...