Functional changes in aging polymorphonuclear leukocytes

Abstract

Background-Previous studies from our laboratory have shown that the expression of L-selectin on polymorphonuclear neutrophils (PMN) decreases as the cell ages in the circulation and that these older PMN have more fragmented DNA and show morphological features of apoptosis. Methods and Results-The present study was designed to compare the functional capabilities of PMN expressing low levels of L-selectin (L-selectin(low)) and the total population of PMN they were isolated from (L-selectin(mixed)). The results show no difference of the baseline filamentous actin (F-actin) content between PMN expressing low and high levels of L-selectin. However, the ability of L-selectin(low) PMN to assemble F-actin was impaired after stimulation by n-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) (1 nmol/L fMLP: P