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.