Vitamin D3-binding protein as a precursor for macrophage activating factor in the inflammation-primed macrophage activation cascade in rats.
When rat peritoneal nonadherent cells were treated with inflammatory lipid metabolites and cultured with adherent cells in 1% fetal calf serum (FCS) supplemented medium RPMI 1640 (FCS medium) for 3 hr, markedly enhanced phagocytic and superoxide generating capacities of macrophages were observed. Stepwise preparation of conditioned medium of lysophosphatidylcholine (lyso-Pc)-treated B cells and untreated T cells in FCS medium generated a potent macrophage activating factor whereas cultivation of lyso-Pc-treated B cells alone in a 1% adult rat serum supplemented medium efficiently generated the macrophage activating factor. Generation of macrophage activating factor requires a precursor protein, serum vitamin D3-binding protein (DBP), as well as participation of lymphocyte glycosidases. The lyso-Pc-inducible beta-galactosidase of B lymphocytes and the Neu-1 sialidase of T lymphocytes modified bovine DBP (bDBP) to yield the macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. In contrast, lyso-Pc-inducible beta-galactosidase of B cells alone modified rat DBP (rDBP) to yield the macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. Thus, we conclude that bDBP carries a trisaccharide composed of N-acetylgalactosamine, galactose, and sialic acid while rDBP carries a disaccharide composed of N-acetylgalactosamine and galactose.
Yamamoto
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Laboratory of Cancer Immunology and Molecular Biology, Albert Einstein Cancer Center, Philadelphia, Pennsylvania 19141, USA.
Naraparaju
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VR
D000818:Animals; D001402:B-Lymphocytes / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D001685:Biological Factors / Q000276:immunology / Q000378:metabolism*; D002417:Cattle; D002762:Cholecalciferol / Q000378:metabolism*; D017077:Culture Media, Conditioned; D005989:Glycerides / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000378:metabolism; D007249:Inflammation / Q000276:immunology; D007848:Laurates / Q000494:pharmacology; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects; D017737:Macrophages, Peritoneal / Q000276:immunology* / Q000378:metabolism; D050178:Monoglycerides; D009439:Neuraminidase / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D014809:Vitamin D-Binding Protein / Q000276:immunology / Q000378:metabolism*
D001685:Biological Factors; D017077:Culture Media, Conditioned; D005989:Glycerides; D007848:Laurates; D008244:Lysophosphatidylcholines; D050178:Monoglycerides; D011498:Protein Precursors; D014809:Vitamin D-Binding Protein; C006065:We 201; D002762:Cholecalciferol; C020777:monolaurin; D006026:Glycoside Hydrolases; D009439:Neuraminidase