Natural killer cell-mediated cytotoxicity does not depend on recognition of mannose 6-phosphate residues.
Interaction of mannose 6-phosphate-specific receptors with their ligands has been suggested to be essential for natural killer cell (NK)-mediated cytotoxicity. Indeed, mannose 6-phosphate-specific receptors and ligands bearing mannose 6-phosphate residues are demonstrable on human peripheral blood leukocytes with NK activity as well as on K-562 NK target cells, allowing at least in principle such an interaction. It can also be shown that NK activity of human peripheral blood leukocytes is inhibited by mannose 6-phosphate. The following observations, however, exclude an essential role of the mannose 6-phosphate receptor-ligand system in NK cell-mediated cytotoxicity. 1) NK cytotoxicity is sensitive to a broad range of structurally unrelated sugar phosphates. 2) NK activity is normal in patients with I cell disease (mucolipidosis II), which due to a genetic defect are unable to synthesize the ligands for the mannose 6-phosphate-specific receptor. 3) NK cytotoxicity is not inhibited by an antiserum against the mannose 6-phosphate receptor, which blocks the receptor function.
D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D004705:Endocytosis; D005347:Fibroblasts / Q000276:immunology; D006600:Hexosephosphates / Q000032:analysis* / Q000494:pharmacology; D006801:Humans; D006867:Hydrolases / Q000032:analysis; D007106:Immune Sera; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D015470:Leukemia, Myeloid, Acute; D008247:Lysosomes / Q000032:analysis; D008360:Mannosephosphates / Q000032:analysis*; D009081:Mucolipidoses / Q000276:immunology
D006600:Hexosephosphates; D007106:Immune Sera; D008360:Mannosephosphates; C027693:mannose-6-phosphate; D006867:Hydrolases