Alterations of regular and mature monocytes are distinct, and dependent of intensity and duration of exercise.

Circulating monocytes comprise functionally distinct regular (CD14bright+) and mature (CD14low+) cells. Cell surface receptors were determined by three colour flow cytometry in 8 healthy control subjects. Compared to regular monocytes, mature monocytes had lower levels of the high affinity Fc gamma receptor 1 (CD64), complement receptor 3 (CD11b), CD45RO and higher levels for HLA-DR, LFA-1 (CD11a/CD18), interleukin-2 receptor (CD25), CD45RA and the Fc gamma receptor 3 (CD16). Both regular and mature monocytes were measured before and up to three hours after four different types of exercise (Ex) in endurance trained athletes (n = 9-16). Immediately after anaerobic exercise of 1 min with a maximal lactate concentration (la max) of 12.3 (SD 1.4) mmol.1-1 and exhaustive exercise of 24 (SD 8) min with a maximal lactate concentration (lamax) of 7.4 (SD 2.6) mmol..-1 mature monocytes increased more than regular monocytes. Exhaustive endurance exercise of 87 (SD 21) min [lamax 3.7 (SD 1.0)] led to a similar increase of regular and mature monocytes. 15-33 min after a 100km run regular monocytes increased significantly, whereas mature monocytes decreased. Up to three hours after the end of all exercises mature monocytes fell below pre-exercise values. In conclusion, duration and intensity of exercise alter distinct maturation stages of monocytes differently. It is probable that the avidity of adhesion molecules like LFA-1 to their endothelial ligands is increased to enable the firm attachment to the endothelium.