title: Structural definition of a potent macrophage activating factor derived from vitamin D3-binding protein with adjuvant activity for antibody production.
abstract: Incubation of human vitamin D3-binding protein (Gc protein), with a mixture of immobilized beta-galactosidase and sialidase, efficiently generated a potent macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. Stepwise incubation of Gc protein with immobilized beta-galactosidase and sialidase, and isolation of the intermediates with immobilized lectins, revealed that either sequence of hydrolysis of Gc glycoprotein by these glycosidases yields the macrophage-activating factor, implying that Gc protein carries a trisaccharide composed of N-acetylgalactosamine and dibranched galactose and sialic acid termini. A 3 hr incubation of mouse peritoneal macrophages with picomolar amounts of the enzymatically generated macrophage-activating factor (GcMAF) resulted in a greatly enhanced phagocytic activity. Administration of a minute amount (10-50 pg/mouse) of GcMAF resulted in a seven- to nine-fold enhanced phagocytic activity of macrophages. Injection of sheep red blood cells (SRBC) along with GcMAF into mice produced a large number of anti-SRBC antibody secreting splenic cells in 2-4 days.
authors.affiliation: Laboratory of Cancer Immunology and Molecular Biology, Albert Einstein Cancer Center, Philadelphia, PA 19141, U.S.A.
authors.forename: N
authors.initials: N
authors.lastname: Yamamoto
mesh_terms: D000276:Adjuvants, Immunologic / Q000502:physiology; D019264:Adoptive Transfer; D000818:Animals; D000917:Antibody Formation; D000921:Antibody-Producing Cells / Q000166:cytology; D002452:Cell Count; D004912:Erythrocytes; D005260:Female; D006801:Humans; D016215:Macrophage-Activating Factors / Q000737:chemistry* / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009439:Neuraminidase / Q000494:pharmacology; D012756:Sheep / Q000097:blood; D013997:Time Factors; D014809:Vitamin D-Binding Protein / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification / Q000494:pharmacology; D001616:beta-Galactosidase / Q000494:pharmacology
chemical_list: D000276:Adjuvants, Immunologic; D016215:Macrophage-Activating Factors; D014809:Vitamin D-Binding Protein; C101908:vitamin D-binding protein-macrophage activating factor; D009439:Neuraminidase; D001616:beta-Galactosidase