| Abstract: | Activation of macrophages with macrophage activating factor (MAF) was evaluated by measuring the intracellular killing activity of murine macrophages against Salmonella typhimurium. Concanavalin A (Con A)-induced MAF-rich fraction was obtained by a Sephadex G-100 column, which contained molecules ranging from 25,000 to 67,000 daltons. The intracellular killing ability of mouse peritoneal macrophages against S. typhimurium was found to be increased by 0.1 m d-mannose as well as by Con A-induced MAF-rich fraction. Both 0.1 m d-mannose and MAF exhibited a similar timing pattern for macrophage activation. The same concentration of d-glucose or l-rhamnose did not change bacterial uptake and intracellular killing by macrophages. Moreover, when MAF-rich fraction was applied to a Con A-Sepharose column, a fraction that was adsorbed on Con A and eluted with 0.1 m α-methyl d-mannoside exhibited MAF activity. These results suggest the possibility that mannopyranosyl residues in the MAF molecules play an important role as a ligand in macrophage activation. |
