Exercise-induced changes in the expression of surface adhesion molecules on circulating granulocytes and lymphocytes subpopulations

This study examined the relationship between exercise-induced changes in the concentration of circulating immunocompetent cells and their surface expression of adhesion molecules: L-selectin (CD62L) and threeß₂-integrins [LFA-1(CD11a/CD18), Mac-1 (CD11b/CD18), and p150/95(CD11c/CD18)]. Eight young male volunteers exercised on a cycle ergometer for 60 min at 60% maximal oxygen uptake. Peripheral blood samples, collected every 30 min throughout exercise and during the 2-h recovery period, were used for flow-cytometric analysis. The experimental results were compared with control data obtained ever 60 min at corresponding times of the nonexercise day. The exercise regimen induced a granulocytosis and a lymphocytosis, mainly due to an elevation of CD8⁺ and CD16⁺ cells. During recovery, a further granulocytosis occurred but accompanied by a lymphopenia. The increased CD8⁺ cell-count during exercise was characterized by a selective mobilization of the CD62L^- and CD11a^high cells, i.e.primed CD8⁺ cells. A postexercise suppression of CD4⁺ cell-count was derived only from CD62L⁺ cells. The CD11b⁺ and CD11c⁺ lymphocytes also increased during exercise, largely attributable to an increase in CD16⁺ cells which co-expressed CD11b and CD11c molecules. The CD62L surface density of granulocytes increased significantly during recovery. This resulted from a selective influx of CD62L^high granulocytes into the circulation. There were no significant changes in per-cell density of the threeß₂-integrins on granulocytes and lymphocytes throughout the experimental period. These results suggest that the cell-surface expression of CD62L (and CD I la) molecules is associated with the differential mobilization of CD8⁺ cells during exercise, the postexercise suppression of CD4^- cell-counts and the granulocytosis following exercise.