Vitamin D-binding protein (group-specific component) is the sole serum protein required for macrophage activation after treatment of peritoneal cells with lysophosphatidylcholine

Immunol Cell Biol. 1993 Aug:71 ( Pt 4):249-57. doi: 10.1038/icb.1993.29.

Abstract

In vitro treatment of mouse peritoneal cells with 1 micrograms lysophosphatidylcholine (lyso-Pc)/mL in serum free-0.1% egg albumin-supplemented RPMI 1640 medium for 30 min, followed by 3 h cultivation in a medium supplemented with human serum, resulted in a greatly enhanced Fc-receptor-mediated phagocytic activity of macrophages. Vitamin D-binding protein (group-specific component [Gc]) of alpha 2-globulin fraction was shown to be the sole serum glycoprotein required for the generation of a potent macrophage-activating factor. When a mixture of lysophosphatidylcholine (lyso-Pc)-treated nonadherent and adherent cells were cultured in a medium supplemented with a small amount of purified Gc protein (1 ng/mL), a greatly enhanced activation of macrophages was demonstrated. The generation of macrophage-activating factor from purified Gc protein was far more efficient than that from whole serum, indicating that a serum component is inhibitory to the activation process of macrophages. While three other major serum glycoproteins (alpha 2-macroglobulin, alpha 2-HS-glycoprotein and haptoglobin) were neither stimulatory nor inhibitory to lyso-Pc-primed macrophage activation, serum albumin (competitively with Gc protein) appeared to be inhibitory to the process of macrophage activation.

Publication types

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

MeSH terms

  • Animals
  • Cells, Cultured
  • Culture Media
  • Female
  • Humans
  • Lysophosphatidylcholines / immunology*
  • Macrophage Activation / immunology*
  • Macrophage-Activating Factors / biosynthesis
  • Macrophages / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Peritoneal Cavity / cytology
  • Phagocytosis / immunology
  • Rabbits
  • Serum Albumin / immunology
  • Vitamin D-Binding Protein / immunology*

Substances

  • Culture Media
  • Lysophosphatidylcholines
  • Macrophage-Activating Factors
  • Serum Albumin
  • Vitamin D-Binding Protein