Exercise-induced stress inhibits both the induction and elicitation phases of in vivo T-cell-mediated immune responses in humans

► Contact-hypersensitivity is a clinically relevant in-vivo measure of T cell-mediated immunity. ► Contact-hypersensitivity was assessed using diphenylcyclopropenone (DPCP). ► Prolonged exercise impaired induction and elicitation phases of T cell-mediated in-vivo immunity. ► Contact-hypersensitivity using DPCP provides a simple tool to assess in-vivo immunity in humans.