Immunological and anti-inflammatory effects of clarithromycin: inhibition of interleukin 1 production of murine peritoneal macrophages

The immunological and anti-inflammatory effects of clarithromycin (CAM), a new oral macrolide antibiotic, were examined in in vitro models such as lymphocyte transformation (LTF) of murine spleen cells, interleukin 1 (IL-1) production of murine peritoneal macrophages and IL-1-induced proliferation of C3H/HeJ mice thymocytes; the results were compared with those achieved by erythromycin (EM). CAM suppressed these responses much more than EM. Murine peritoneal macrophages precultured with CAM showed diminished IL-1 production, but macrophages precultured with EM did not, indicating that CAM has suppressive effects on the early phase of IL-1 production of murine peritoneal macrophages. Suppressive effects of CAM on IL-1 production by macrophages and proliferation of lymphocytes were independent of prostaglandin biosynthesis, since this drug had no effect on cyclooxygenase activity. Additional immunosuppressive and anti-inflammatory activities of CAM may explain its superior clinical effect.