Leukotriene B4 action on endothelium mediates augmented neutrophil/endothelial adhesion

The attachment of human polymorphonuclear leukocytes (PMN) to bovine endothelial monolayers is increased by pretreatment of the endothelial cells with leukotriene B4 (LTB4). The response is dose dependent with a maximum at 10(-6) M, requires no more than 1 min of preincubation for the maximal effect, and decays linearly over 30 min once the LTB4 is removed. Preincubation of PMN with LTB4 does not augment subsequent adhesion to a plastic substratum or an untreated monolayer of endothelial cells and eliminates the augmented attachment to LTB4-pretreated endothelial cells. The simultaneous exposure of both cell types during the adhesion interaction gives a biphasic dose-related increment, suggesting that the inhibition of the neutrophil adherence is less marked than with a pretreatment interval. Thus, the LTB4-dependent adherence of PMN to endothelial cells is selectively mediated by endothelial cells, is dose related, is reversible upon removal of the agonist from the endothelial cells, and is opposed by the direct action of LTB4 on the PMN.