Activation phenotypes defined by the coordinated expression of activation markers discriminate TCR-mediated and bystander T cell responses

T cells, and defined activation phenotypes that distinguish TCR-activated from bystander-activated T cells. In anti-viral responses, peptide stimulation mainly induced bystander activation, yet bystander T cells contributed minimally to cytokine production. Our findings provide a framework for identifying T cell response types in diverse clinical contexts.