Acute exercise mobilises CD8+ T lymphocytes exhibiting an effector-memory phenotype

The results show a strong differential mobilisation of CD8TL subsets (RAEM > EM > CM > naïve); during high intensity exercise the greatest increase was observed for RAEM CD8Tls (+450%) and the smallest for naïve cells (+84%). Similarly, CD56dim NK cells (+995%) were mobilised to a greater extent than CD56bright (+153%) NK cells. In conclusion, memory CD8TL that exhibit a high effector and tissue-migrating potential are preferentially mobilised during exercise. This finding unifies a range of independent observations regarding exercise-induced phenotypic and functional changes in circulating lymphocytes. The selective mobilisation of cytotoxic tissue-migrating subsets, both within the NK and CD8TL population, may enhance immune-surveillance during exercise.