CMV amplifies T-cell redeployment to acute exercise independently of HSV-1 serostatus

Purpose: Latent cytomegalovirus (CMV) infection has been shown to alter the lymphocyte response to acute aerobic exercise, likely due to the corresponding increase in exercise-responsive memory CD8⁺ T cells. It is unknown if latent infection with another herpesvirus, herpes simplex virus 1 (HSV-1), also plays a role in shaping the lymphocyte response to exercise. Methods: Thirty-two men (ages 39.3 ± 14.7 yr) counterbalanced by CMV and HSV-1 serostatus (positive/negative) cycled for 30 min at ~80% peak power. Blood sampled before, immediately after, and 1 h after exercise was analyzed by flow cytometry for T-cell subset enumeration. Results: In resting blood, HSV-1 ⁺ had fewer lymphocytes, CD4⁺ T cells, KLRG1 ^-CD28⁺CD4⁺ T cells, and CD45RA ^-CCR7⁺CD4⁺ T cells than HSV-1^-, whereas CMV⁺ had increased numbers of lymphocytes, CD8⁺ T cells, KLRG1⁺CD28^-CD4⁺ and CD8⁺ T cells, and CD45RA⁺ CCR7^-CD8⁺ T cells and a lower CD4:CD8 T-cell ratio than CMV^-. After exercise, CMV⁺ had a greater mobilization of CD8⁺ T cells, KLRG1 ⁺CD28^-CD4⁺ and CD8⁺ T cells, and CD45RA⁺CCR7^-CD8⁺ T cells independently of HSV-1 serostatus, as well as a greater egress of these subsets 1 h after exercise. HSV serostatus did not influence total CD8⁺ T-cell response to exercise. Conclusions: The impact of latent CMV infection on the redeployment of T-cell subsets with exercise is independent of HSV-1 infection. This is most likely due to the unique ability of CMV to alter the composition of the memory T-cell pool in favor of exercise-responsive T-cell subsets.