Effect of clarithromycin on macrophage functions]

Recently, it has been suggested that macrolide antibiotics act as immunomodulators. In this study, we evaluated the effect of clarithromycin (CAM) on macrophage function. We used the mouse macrophage cell line, J774.1. The following direct effects of CAM on macrophage function were evaluated: chemotaxis to CAM, chemokinetic effect of CAM, and the effect of CAM on macrophage growth. In order to examine the indirect effects of CAM on macrophage functions, we preincubated macrophages with several concentrations of CAM and then removed the CAM. Thereafter, the phagocytosis of beads, cytocidal activity against Candida albicans, and chemotaxis to lipopolysaccharide were evaluated. In addition, the indirect effects of CAM on endoxan (4 mg/ml) treated macrophage phagocytosis, cytocidal activity, and chemotaxis were evaluated. CAM (at the concentration between 0.04 and 0.2 microgram/ml) directly stimulated macrophage chemotaxis and chemokinesis. In addition, CAM dose-dependently stimulated the growth of macrophages. CAM pretreatment (for 4 hours at the concentrations between 0.04 and 0.2 microgram/ml) stimulated macrophage phagocytosis, cytocidal activity against Candida albicans, and chemotaxis to lipopolysaccharide. In addition, CAM recovered macrophage phagocytosis, cytocidal activity, and chemotaxis which were decreased after endoxan exposure. These results suggest that CAM has direct and indirect effects on macrophage functions.