Vitamin D3 binding protein required for in vitro activation of macrophages after alkylglycerol treatment of mouse peritoneal cells.
In vitro treatment of peritoneal cells with dodecylglycerol (DDG) in 10% foetal calf serum (FCS) supplemented medium RPMI-1640 results in a greatly enhanced Fc receptor-mediated phagocytic activity of macrophages. This macrophage activation process requires a serum factor in the alpha 2-globulin fraction. When mouse peritoneal cells were treated with 50 ng DDG/ml in a serum-free 0.1% egg albumin-supplemented medium RPMI-1640 (EA medium) for 30 min and cultured in EA medium containing electrophoretically fractionated alpha 2-globulin for 3 hr, a markedly enhanced activation of macrophages was observed. To improve fractionation of alpha 2-globulin, FCS was first precipitated with 50% saturated ammonium sulphate and then the supernatant electrophoretically fractionated. The resultant alpha 2-globulin fraction was unable to support activation of macrophages. Vitamin D3 binding protein (DBP) of the alpha 2-globulin fraction is known to be precipitable by 50% saturated ammonium sulphate. When human alpha 2-globulin was treated with antiserum against human DBP and used in a medium for cultivation of DDG-treated peritoneal cells, no significant activation of macrophages was observed. Cultivation of DDG-treated peritoneal cells in a medium containing a low concentration of purified human DBP (group specific component, Gc) produced a greatly enhanced ingestion activity of macrophages. Purified human Gc protein, when used in an EA medium for step-wise cultivation of DDG-treated B and untreated T cells, was efficiently converted to a macrophage-activating factor.
Yamamoto
N
N
Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140.
Homma
S
S
Haddad
J G
JG
Kowalski
M A
MA
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D005989:Glycerides / Q000494:pharmacology; D007848:Laurates / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D050178:Monoglycerides; D010529:Peritoneal Cavity / Q000166:cytology; D010587:Phagocytosis / Q000276:immunology; D014809:Vitamin D-Binding Protein / Q000276:immunology*
D005989:Glycerides; D007848:Laurates; D050178:Monoglycerides; D014809:Vitamin D-Binding Protein; C020777:monolaurin