In vitro and ex vivo effects of erythromycin A, azithromycin and josamycin on the splenic response to specific antigens and mitogens.

The immunomodulatory properties of antimicrobial agents and their clinical impact have been the focus of worldwide interest in recent years. In this study, the effects of different treatments with 14-, 15- and 16-membered ring macrolides on the mitogen-induced proliferative response of lymphocytes and the splenic response to immunization with sheep erythrocytes have been tested by in vitro and ex vivo assays in a murine experimental model. We observed that the in vivo administration of these antibiotics to mice induces a compensatory mechanism that abrogates the suppression observed by in vitro assays. Thus, physiological parameters may be important when testing the immunopharmacological effects of antibiotics.