Latent Cytomegalovirus infection amplifies CD8 T-lymphocyte mobilisation and egress in response to exercise

Exercise induces mobilisation of CD8(+) T lymphocytes (CD8TL) into the peripheral blood. This response is largely confined to effector-memory CD8TLs, antigen experienced cells which have a strong tissue-homing and effector potential This study investigated whether effector-memory cells also account for the CD8TL egress from peripheral blood following exercise As latent Cytomegalovirus (CMV) infection is associated with a robust expansion in the number and proportion of effector-memory CD8TLs, we also investigated if CMV serostatus was a determinant of the CD8TL responses to exercise Fourteen males (Mean age 35, SD +/- 14 yrs), half of whom were CMV seropositive (CMV+), ran on a treadmill for 60 min at 80% VO2 max Blood was collected at baseline, during the final minute of exercise, and 15 min and 60 min thereafter CD8TL memory subsets were characterised by flow cytometry, using the cell-surface markers CD45RA, CD27, and CD28 The results confirmed that CD8TL5 with an effector-memory phenotype (CD27(-)CD28(-)CD45RA(-/)) exhibited the largest increase during exercise (+200% to +250%), and also showed the largest egress from blood 60 min post-exercise (down to 40% of baseline values) Strikingly, the mobilisation and subsequent egress of total CD8TLs was nearly twice as large in CMV+ individuals This effect appeared specific to CD8TLs, and was not seen for CD4(+) T lymphocytes or total lymphocytes This effect of CMV serostatus was largely driven by the higher numbers of exercise-responsive effector-memory CD8TLs in the CMV+ participants This is the first study to demonstrate that infection history is a determinant of immune system responses to exercise. (C) 2010 Elsevier Inc. All rights reserved