Lipopolysaccharide-coated erythrocytes activate human neutrophils via CD14 while subsequent binding is through CD11b/CD18.
Interaction of LPS with monocytes and neutrophils is known to occur via CD14 and is strongly enhanced by LPS-binding protein (LBP). Integrins as well as CD14 play a role in the interaction of erythrocytes (E) coated with LPS or whole Gram-negative bacteria with phagocytes. We reasoned that the density of LPS on a particle is an important determinant in these interactions. Therefore, E were coated with different concentrations of LPS (ELPS). The binding of these ELPS to neutrophils was evaluated by flow cytometry. Simultaneously, we measured fMLP receptor expression to evaluate neutrophil activation. ELPS only bound to neutrophils in the presence of LBP. Blocking CD14 inhibited both activation and binding, whereas blocking complement (C) receptor 3 (CR3) inhibited binding but not activation. TNF activation restored ELPS binding in CD14-blocked cells but not in cells in which CR3 was blocked. Salmonella minnesota did bind to neutrophils independent of CR3 or CD14. The addition of LBP enhanced binding twofold, and this surplus was dependent upon CD14 but not on CR3. We conclude that ELPS interact with neutrophils via CD14, initially giving rise to cell activation; subsequently, binding is solely mediated by activated CR3.
Troelstra
A
A
Eijkman-Winkler Institute for Medical Microbiology, Utrecht University, The Netherlands. a.troelstra@lab.azu.nl
de Graaf-Miltenburg
L A
LA
van Bommel
T
T
Verhoef
J
J
Van Kessel
K P
KP
Van Strijp
J A
JA
D000209:Acute-Phase Proteins; D018821:CD18 Antigens / Q000378:metabolism*; D002352:Carrier Proteins / Q000502:physiology; D002448:Cell Adhesion / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology* / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000502:physiology*; D008070:Lipopolysaccharides / Q000276:immunology* / Q000378:metabolism; D016177:Macrophage-1 Antigen / Q000378:metabolism*; D008562:Membrane Glycoproteins; D018375:Neutrophil Activation / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D011485:Protein Binding / Q000276:immunology; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000378:metabolism; D018000:Receptors, Peptide / Q000378:metabolism; D012475:Salmonella / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D018821:CD18 Antigens; D002352:Carrier Proteins; D016650:Fluorescein-5-isothiocyanate; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D016177:Macrophage-1 Antigen; D008562:Membrane Glycoproteins; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D018000:Receptors, Peptide; D014409:Tumor Necrosis Factor-alpha; D000099231:Lipopolysaccharide-Binding Protein