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.