title: Lectin-like molecules on the murine macrophage cell surface.
abstract: Lectin-like molecules on the surface of murine peritoneal exudate macrophages induced by thioglycolate or an anti-tumor streptococcal preparation, OK-432, were investigated and isolated. Furthermore, their sugar-binding specificities and their role in macrophage-mediated tumor cytotoxicity were examined. A neoglycoprotein, D-galactose (Gal)-bovine serum albumin, bound to these murine peritoneal macrophages. This binding of Gal-bovine serum albumin was inhibited by D-galactose, and by complex-type oligosaccharides (unit B) and high mannose-type oligosaccharides (unit A) prepared from porcine thyroglobulin. When thioglycolate-elicited macrophages were activated by lipopolysaccharide and/or the culture supernatant of concanavalin A-activated mouse spleen cells, they became tumoricidal and the number of the lectin-like molecules on the macrophage surface was found to increase. Since the binding and cytotoxic activities of these tumoricidal macrophages toward tumor cells were partially inhibited by D-galactose, the D-galactose-binding lectin-like molecules on the surface of tumoricidal macrophages might play an important role in macrophage-mediated cytotoxicity. These lectin-like molecules were then isolated from solubilized murine peritoneal exudate cells labeled with pyridoxal 5'-phosphate and sodium [3H]borohydride by affinity chromatography on columns of asialo unit B oligosaccharide-Sepharose 4B and/or beta-D-galactose-Bio-Gel P-100. The proteins bound to the asialo unit B oligosaccharide-Sepharose 4B column and eluted specifically were found to have approximate molecular weights of 79 000 and 18 000, and the protein bound to and eluted from the beta-D-galactose-Bio-Gel P-100 column had an approximate molecular weight of 77 000. These isolated proteins bound to the surface of glutaraldehyde-fixed tumor cells, and their binding was inhibited by D-galactose and also by D-mannose. Since most of the 77 kDa protein bound to the asialo unit B oligosaccharide-Sepharose 4B, this protein was assumed to be identical with the 79 kDa protein. These results suggest that the lectin-like molecules on murine macrophages have wide specificity and that one lectin-like molecule can bind both D-galactose and D-mannose.
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins; D002241:Carbohydrates / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D002448:Cell Adhesion; D005122:Exudates and Transudates; D005690:Galactose / Q000378:metabolism*; D037102:Lectins; D008262:Macrophage Activation; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011485:Protein Binding / Q000187:drug effects; D012710:Serum Albumin, Bovine; D013329:Structure-Activity Relationship
chemical_list: D002135:Calcium-Binding Proteins; D002241:Carbohydrates; D002352:Carrier Proteins; D037102:Lectins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; C023550:galactose-binding protein; D012710:Serum Albumin, Bovine; D005690:Galactose