Polymorphonuclear leukocytes L-selectin expression decreases as they age in circulation

Mature polymorphonuclear leukocytes (PMNs) isolated from New Zealand White rabbits were analyzed by flow cytometry to determine effects of senescence on L-selectin expression in PMNs. Analysis of rabbit PMNs by flow cytometry indicated the presence of decreasing levels of L-selectin expression due to cellular senescence. Older circulating PMNs also exhibited constitutive shedding of L-selectin due to interactions with the endothelium in the microvessels.