The Fcgamma receptor-mediated respiratory burst of rolling neutrophils to cytokine-activated, immune complex-bearing endothelial cells depends on L-selectin but not on E-selectin.
Intracellular H2O2 generation, as a measure of the respiratory burst, was determined after stimulation of neutrophils by immune complex (IC)-bearing human umbilical vein endothelial cells. Under static conditions, neutrophils basically responded to the immune deposits on resting endothelial cells. The rotating shear forces of approximately 0.7 dynes/cm2, corresponding to the physiological flow in postcapillary venules, completely abolished this basal H2O2 generation. After activation of the IC-bearing endothelial layers with interleukin-1 (IL-1) or tumor necrosis factor (TNF), or both, for 4 hours, rolling adhesion of the neutrophils was induced, accompanied by considerable H2O2 production. The neutrophil respiratory burst was prominently inhibited by anti-FcgammaRIII MoAb 3G8 (72.4%), and partially by MoAb 2E1 against FcgammaRII (38.5%). Both MoAbs together inhibited the Fc-mediated H2O2 generation by 93. 4%. The respiratory burst and rolling adhesion were markedly blocked by MoAb LAM1-3 against L-selectin (91.3%), whereas the nonfunctional anti-L-selectin MoAb LAM1-14 was ineffective. F(ab)2' fragments of MoAb 7A9 against E-selectin inhibited neutrophil rolling by 98.6%, but not the respiratory burst. Moreover, rolling adhesion of neutrophils and the related oxidative burst were CD11b/CD18- independent. In summary, L-selectin has a unique auxiliary function in triggering the FcgammaR-mediated respiratory burst of rolling neutrophils to IC-bearing endothelial cells, thereby substituting CD11b/CD18 under conditions of flow.
Fröhlich
D
D
Institute of Toxicology, Federal Institute of Technology, Schwerzenbach, Switzerland.
Spertini
O
O
Moser
R
R
D000936:Antigen-Antibody Complex / Q000276:immunology; D002450:Cell Communication / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D016207:Cytokines / Q000276:immunology / Q000494:pharmacology; D019040:E-Selectin / Q000276:immunology; D004730:Endothelium, Vascular / Q000166:cytology* / Q000276:immunology*; D006801:Humans; D019041:L-Selectin / Q000276:immunology*; D009504:Neutrophils / Q000166:cytology* / Q000276:immunology*; D011961:Receptors, Fc / Q000276:immunology*; D016897:Respiratory Burst / Q000276:immunology*
D000936:Antigen-Antibody Complex; D016207:Cytokines; D019040:E-Selectin; D011961:Receptors, Fc; D019041:L-Selectin