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 su rface expression of adhesion molecules: L-selectin (CD62L) and three b eta(2)-integrins [LFA-1(CD11a/CD18), Mac-1 (CD11b/CD18), and p150/95(C Dllc/CD18)]. Eight young male volunteers exercised on a cycle ergomete r for 60 min at 60% maximal oxygen uptake. Peripheral blood samples, c ollected every 30 min throughout exercise and during the 2-h recovery period, were used for flow-cytometric analysis, The experimental resul ts were compared with control data obtained ever 60 min at correspondi ng times of the nonexercise day. The exercise regimen induced a granul ocytosis 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 suppr ession of CD4(+) cell-count was derived only from CD62L(+) cells. The CD11b(+) and CD11c(+) lymphocytes also increased during exercise, larg ely attributable to an increase in CD16(+) cells which co-expressed CD 11b and CD11c molecules. The CD62L surface density of granulocytes inc reased significantly during recovery. This resulted from a selective i nflux of CD62L(high) granulocytes into the circulation. There were no significant changes in per-cell density of the three beta(2)-integrins on granulocytes and lymphocytes throughout the experimental period. T hese results suggest that the cell-surface expression of CD62L (and CD 11a) molecules is associated with the differential mobilization of CD8 (+) cells during exercise, the postexercise suppression of CD4(+) cell -counts and the granulocytosis following exercise.