Structural definition of a potent macrophage activating factor derived from vitamin D3-binding protein with adjuvant activity for antibody production

Mol Immunol. 1996 Oct;33(15):1157-64. doi: 10.1016/s0161-5890(96)00081-8.


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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adjuvants, Immunologic / physiology
  • Adoptive Transfer
  • Animals
  • Antibody Formation
  • Antibody-Producing Cells / cytology
  • Cell Count
  • Erythrocytes
  • Female
  • Humans
  • Macrophage-Activating Factors / chemistry*
  • Macrophage-Activating Factors / pharmacology
  • Macrophages, Peritoneal / immunology
  • Mice
  • Mice, Inbred BALB C
  • Neuraminidase / pharmacology
  • Sheep / blood
  • Time Factors
  • Vitamin D-Binding Protein / chemistry*
  • Vitamin D-Binding Protein / drug effects
  • Vitamin D-Binding Protein / isolation & purification
  • Vitamin D-Binding Protein / pharmacology
  • beta-Galactosidase / pharmacology


  • Adjuvants, Immunologic
  • Macrophage-Activating Factors
  • Vitamin D-Binding Protein
  • vitamin D-binding protein-macrophage activating factor
  • Neuraminidase
  • beta-Galactosidase