The effects of age and viral serology on γδ T-cell numbers and exercise responsiveness in humans

gamma delta T-cells are cytotoxic effector cells that preferentially migrate to peripheral tissues and recognize many types of antigen. We examined the effects of age and viral serology on the exercise responsiveness of gamma delta T-cells. Blood was collected from 17 younger (age: 23-35 yrs) and 17 older (50-64 yrs) healthy males matched for cytomegalovirus (CMV), Epstein-Barr virus, herpes simplex virus-1 and Parvovirus B19 serologic status before and after a single bout of cycling exercise. Older had lower numbers and proportions of gamma delta T-cells than younger, while CMV was associated with increased numbers and proportions of gamma delta T-cells in younger but not older. Exercise evoked a similar to 2-fold increase in circulating gamma delta T-cell numbers. The magnitude of this response was 3-times greater in younger compared to older, and 1.6-times greater in younger CMV-infected compared to younger non CMV-infected. To conclude, gamma delta T-cell numbers and exercise responsiveness decreases with age and may contribute to impaired immunosurveillance after acute acute physical stress. (C) 2013 Elsevier Inc. All rights reserved.