Further studies on erythromycin effects on cellular immune functions in vitro and in vivo. Enhancement of neutrophil motility by erythromycin combined with ascorbate or thiamine

Abstract

The effects of erythromycin on neutrophil random migration and motility to the leucoattractant endotoxin-activated serum (EAS), post-phagocytic hexosemonophosphate shunt activity (HMS), myeloperoxidase (MPO)-mediated iodination of ingested Candida albicans and lymphocyte transformation to the mitogens phytohaemagglutinin (PHA) and concanavalin A (Con A) have been investigated in vitro and in vivo. For in-vitro studies erythromycin was investigated as the base compound and as the stearate and succinate forms. Erythromycin stearate was used for in-vivo studies in normal adult volunteers. Erythromycin in vitro but not in vivo caused significant stimulation of neutrophil motility and random migration at concentrations of 10⁻⁴ M -5 × 10⁻⁴ M. These concentrations caused inhibition of MPO-mediated iodination. Slight but insignificant stimulation of lymphocyte-transformation to both mitogens following ingestion of erythromycin was observed. The migration-stimulatory effects of erythromycin were potentiated by ascorbate and thiamine in vitro and by thiamine in vivo. Using the horse-radish peroxidase (HRP)/H₂O₂/sodium iodide system it was demonstrated that the enhancing effect of erythromycin on neutrophil motility and lymphocyte transformation was due to the anti-oxidant activity of the anti biotic. Exposure to the HRP/H₂O₂/iodide system had no adverse effects on the antimicrobial activity of erythromycin.