Dual function of macrophage galactose/N-acetylgalactosamine-specific lectins: glycoprotein uptake and tumoricidal cellular recognition.
We investigated whether the interaction of peritoneal macrophages with extracellular ligands is mediated by C-type lectins specific for galactose and N-acetylgalactosamine. The carbohydrate-binding domain of mouse galactose/N-acetylgalactosamine-specific lectin was prepared in a recombinant form. The purified recombinant lectins were tested for competitive inhibition against glycoprotein uptake and against tumoricidal effect. Thioglycolate-elicited macrophages internalized galactosylated bovine serum albumin in vitro. The internalization was blocked by recombinant macrophage lectins. Activated macrophages obtained after intraperitoneal injection of a nonspecific immune potentiator, OK432, did not internalize galactosylated bovine serum albumin. These cells elicited a cytotoxic effect against P815 murine mastocytoma cells, and the effect was blocked by recombinant macrophage lectins. These results indicated that galactose/N-acetylgalactosamine-specific C-type lectins expressed on the surface of inflammatory macrophages and on activated tumoricidal macrophages mediate two distinct functions, i.e. glycoprotein uptake and tumoricidal effector mechanisms.
Kawakami
K
K
Division of Chemical Toxicology and Immunochemistry, Faculty of Pharmaceutical Sciences, University of Tokyo.
Yamamoto
K
K
Toyoshima
S
S
Osawa
T
T
Irimura
T
T
D000116:Acetylgalactosamine / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D003602:Cytotoxicity, Immunologic; D004705:Endocytosis; D005260:Female; D005690:Galactose / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism* / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000502:physiology*; D012515:Mast-Cell Sarcoma / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D012710:Serum Albumin, Bovine / Q000378:metabolism; D014407:Tumor Cells, Cultured
D006023:Glycoproteins; D037102:Lectins; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D012710:Serum Albumin, Bovine; D000116:Acetylgalactosamine; D005690:Galactose