Role of endothelial leukocyte adhesion molecule-1 and platelet-activating factor in neutrophil adherence to IL-1-prestimulated endothelial cells. Endothelial leukocyte adhesion molecule-1-mediated CD18 activation.
Adherence of neutrophils to endothelium is a key event in the sequence of inflammatory leukocyte responses. Double-color FACS analysis was used to determine the extent and kinetics of neutrophil adherence to rIL-1 beta-pretreated endothelial cells (EC). Neutrophils bound very avidly when the EC were prestimulated for 4 to 6 h with rIL-1 beta. Anti-ELAM-1 F(ab)2 fragments inhibited this adherence for more than 80%. On the other hand, anti-CD18 F(ab)2 fragments also inhibited the neutrophil adherence (40 to 50%). Combined use of anti-ELAM-1 and anti-CD18 F(ab)2 fragments completely prevented adherence. Neutrophils became activated as soon as they made contact with the rIL-1 beta-pretreated EC. First, neutrophils depleted of intracellular ATP showed a clearly decreased adherence completely dependent on ELAM-1-mediated binding, i.e., without additional effects of CD18 adhesion proteins. Thus, CD18 is activated during neutrophil adherence and then participates in the binding process. Secondly, the neutrophils responded with a transient rise in [Ca2+]i upon binding to rIL-1 beta-pretreated EC, which was demonstrated to be caused by endothelial cell-associated platelet-activating factor (PAF). However, the extent of neutrophil adherence to rIL-1 beta-pretreated EC was not affected by the use of the PAF-receptor antagonist WEB 2086, or removal of the EC-bound PAF. The only effect was a complete dependency of the neutrophil adherence on ELAM-1-mediated binding, although anti-CD18 mAb still induced 40 to 50% inhibition under these conditions. We therefore conclude that ELAM-1-mediated binding is the major mechanism for CD18 activation during neutrophil adherence to rIL-1 beta-pretreated EC.
Kuijpers
T W
TW
Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam.
Hakkert
B C
BC
Hoogerwerf
M
M
Leeuwenberg
J F
JF
Roos
D
D
D015703:Antigens, CD / Q000502:physiology*; D018821:CD18 Antigens; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000502:physiology*; D019040:E-Selectin; D004730:Endothelium, Vascular / Q000502:physiology*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D019041:L-Selectin; D009504:Neutrophils / Q000502:physiology*; D010972:Platelet Activating Factor / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology
D015703:Antigens, CD; D018821:CD18 Antigens; D015815:Cell Adhesion Molecules; D019040:E-Selectin; D007375:Interleukin-1; D010972:Platelet Activating Factor; D011994:Recombinant Proteins; D019041:L-Selectin; D002118:Calcium