ALTERATIONS OF REGULAR AND MATURE MONOCYTES ARE DISTINCT, AND DEPENDENT OF INTENSITY AND DURATION OF EXERCISE

Circulating monocytes comprise functionally distinct regular (CD14(bri ght+)) and mature (CD14(low+)) cells. Cell surface receptors were dete rmined by three colour flow cytometry in 8 healthy control subjects. C ompared to regular monocytes, mature monocytes had lower levels of the high affinity Fc gamma receptor 1 (CD64), complement receptor 3 (CD11 b), CD45RO and higher levels for HLA-DR, LFA-1 (CD11a/CD18), interleuk in-2 receptor (CD25), CD45RA and the Fc gamma receptor 3 (CD16). Both regular and mature monocytes were measured before and up to three hour s after four different types of exercise (Ex) in endurance trained ath letes (n=9-16). Immediately after anaerobic exercise of 1 min with a m aximal lactate concentration (la(max)) of 12.3 (SD 1.4) mmol.l(-1) and exhaustive exercise of 24 (SD 8) min with a maximal lactate concentra tion (la(max)) of 7.4 (SD 2.6) mmol.l(-1) mature monocytes increased m ore than regular monocytes. Exhaustive endurance exercise of 87 (SD 21 ) min [la(max) 3.7 (SD 1.0)] led to a similar increase of regular and mature monocytes. 15-33 min after a 100km run regular monocytes increa sed significantly, whereas mature monocytes decreased. Up to three hou rs after the end of all exercises mature monocytes fell below pre-exer cise values. In conclusion, duration and intensity of exercise alter d istinct maturation stages of monocytes differently. It is probable tha t the avidity of adhesion molecules like LFA-1 to their endothelial li gands is increased to enable the firm attachment to the endothelium.