Human leukocyte elastase, cathepsin G, and lactoferrin: family of neutrophil granule glycoproteins that bind to an alveolar macrophage receptor.
Interactions between polymorphonuclear neutrophils and mononuclear phagocytes are potentially of great importance in a variety of inflammatory processes. As part of a continuing effort to elucidate the physiologic importance of human alveolar macrophage receptor-mediated binding of neutrophil (leukocyte) elastase, I have studied the binding of leukocyte elastase and two other neutrophil granule glycoproteins, cathepsin G and lactoferrin, to human alveolar macrophages. Saturable binding of all three ligands at 0 degrees C was observed, with equilibrium dissociation constants of 4.0 x 10(-7), 2.0 x 10(-7), and 1.7 x 10(-6) M, respectively. All bound to a similar number (54-73 x 10(6)) of sites per cell. Binding of all three ligands was inhibited by the polysaccharide fucoidin, and extensive cross-inhibition of their binding to macrophages was observed. The results indicate that alveolar macrophages possess a relatively low-affinity, high-volume receptor for a family of neutrophil granule glycoproteins, which would be ideally suited for clearing released neutrophil granule contents from the extracellular space in inflamed tissues.
D001667:Binding, Competitive; D056649:Cathepsin G; D002403:Cathepsins / Q000097:blood*; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007700:Kinetics; D007781:Lactoferrin / Q000097:blood*; D007782:Lactoglobulins / Q000097:blood*; D008264:Macrophages / Q000378:metabolism*; D009504:Neutrophils / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000097:blood*; D011955:Receptors, Drug / Q000378:metabolism*; D012697:Serine Endopeptidases
D006023:Glycoproteins; D007782:Lactoglobulins; D011955:Receptors, Drug; D002403:Cathepsins; D007781:Lactoferrin; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase