Role of carbohydrates in rat leukemia cell-liver macrophage cell contacts.
The mechanism by which macrophages recognize tumor cells is still unknown. We have studied interactions between rat liver macrophages and rat L 5222 leukemia cells. These tumor cells, but not normal leukocytes or erythrocytes, adhere to freshly isolated macrophages in vitro. Binding of tumor cells by macrophages can be inhibited by N-acetyl-D-galactosamine, D-galactose and more potently by glycoproteins with terminal N-acetyl-D-galactosamine or D-galactose residues. Tumor cell adhesion is calcium-dependent. The relevant leukemia cell membrane structures which bear terminal beta-D-galactosyl or related residues have been determined as trypsin- and pronase-sensitive, and hence may presumably be glycoproteins. The tumor cell receptor on liver macrophages appears to be a lectin with the carbohydrate specificity N-acetyl-D-galactosamine greater than D-galactose greater than L-fucose.
D000116:Acetylgalactosamine / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000502:physiology; D002240:Carbohydrate Sequence; D002448:Cell Adhesion; D002478:Cells, Cultured; D005690:Galactose / Q000378:metabolism*; D007942:Leukemia, Experimental / Q000503:physiopathology*; D008099:Liver / Q000166:cytology; D008264:Macrophages / Q000502:physiology*; D051381:Rats
D000116:Acetylgalactosamine; D002118:Calcium; D005690:Galactose