Comparative effects of roxithromycin and erythromycin on cellular immune functions in vitro. 2. Chemotaxis and phagocytosis of 3H-Staphylococcus aureus by human macrophages.

The in vitro effects of roxithromycin on human macrophage activity were compared with those of erythromycin. Half the MIC of roxithromycin significantly enhanced the phagocytosis of 3H-labelled Staphylococcus aureus by human macrophages. Bacterial phagocytosis was also increased after pre-incubation of staphylococci with roxithromycin. Erythromycin displayed a less stimulating effect. Pre-incubation of macrophages with the drugs caused a depression of staphylococcal uptake by phagocytes. Macrophage chemotaxis was unchanged in the presence of both macrolides.