Loss of L-Selectin (CD62L) on Human Neutrophils Following Exudation in Vivo

L-selectin, an adhesion molecule expressed on the surface of peripheral blood neutrophils, mediates the rolling of neutrophils along vascular endothelium. Stimulation of neutrophils in vitro causes decreased expression of L-selectin on the surface of neutrophils due to shedding. In this study, we have demonstrated that human exudative neutrophils isolated from both skin lesions and from pus exhibit little expression of L-selectin. Although a dramatic accumulation of exudative neutrophils is observed in the skin lesions within 24 hr, there is no accompanying increase in soluble L-selectin. In addition, the levels of soluble L-selectin in the extracellular tissue fluid (97.2 ± 12.7 μg/ml, n = 8) are only 20% of that observed in peripheral plasma (482.4 ± 35.9 μg/ml). These data suggest that shedding of L-selectin from the surface of neutrophils occurs in the peripheral circulation as a prelude to diapedesis of neutrophils into peripheral tissues.