title: Exercise-induced stress inhibits both the induction and elicitation phases of in vivo T-cell-mediated immune responses in humans.
abstract: Little is known about the influence of exercise on induction and elicitation phases of in vivo immunity in humans. We used experimental contact-hypersensitivity, a clinically relevant in vivo measure of T cell-mediated immunity, to investigate the effects of exercise on induction and elicitation phases of immune responses to a novel antigen. The effects of 2 h-moderate-intensity-exercise upon the induction (Study One) and elicitation of in vivo immune memory (Study Two) to diphenylcyclopropenone (DPCP) were examined. Study One: matched, healthy males were randomly-assigned to exercise (N=16) or control (N=16) and received a primary DPCP exposure (sensitization), 20 min after either 2 h running at 60% V O(2peak) (EX) or 2 h seated rest (CON). Four weeks later, participants received a low, dose-series DPCP challenge (elicitation) on their upper inner arm, which was read at 24 and 48 h as clinical score, oedema (skinfold thickness) and redness (erythema). Study Two: pilot; 13 healthy males were sensitized to DPCP. Elicitation challenges were repeated every 4 weeks until responses reached a reproducible plateau. Then, N=9 from the pilot study completed both EX and CON trials in a randomized order. Elicitation challenges were applied and evaluated as in Study One. Results demonstrate that exercise-induced stress significantly impairs both the induction (oedema -53% at 48 h; P<0.001) and elicitation (oedema -19% at 48 h; P<0.05) phases of the in vivo T-cell-mediated immune response. These findings demonstrate that prolonged moderate-intensity exercise impairs the induction and elicitation phases of in vivo T-cell-mediated immunity. Moreover, the induction component of new immune responses appears more sensitive to systemic-stress-induced modulation than the elicitation component.
authors.affiliation: College of Health and Behavioural Sciences, Bangor University, Bangor LL57 2PZ, UK.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Harper Smith
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Coakley
authors.forename: Mark D
authors.initials: MD
authors.lastname: Ward
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Macfarlane
authors.forename: Peter S
authors.initials: PS
authors.lastname: Friedmann
authors.forename: Neil P
authors.initials: NP
authors.lastname: Walsh
mesh_terms: D000328:Adult; D000941:Antigens / Q000008:administration & dosage / Q000276:immunology; D003430:Cross-Sectional Studies; D003521:Cyclopropanes / Q000008:administration & dosage / Q000276:immunology; D003877:Dermatitis, Contact / Q000276:immunology; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007108:Immune Tolerance; D007111:Immunity, Cellular / Q000502:physiology*; D007114:Immunization; D007156:Immunologic Memory; D008297:Male; D010101:Oxygen Consumption; D010865:Pilot Projects; D012420:Running; D013312:Stress, Physiological / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D055815:Young Adult
chemical_list: D000941:Antigens; D003521:Cyclopropanes; C029402:diphenylcyclopropenone