Effects of cefotaxime on neutrophil and lymphocyte functions

The effects of cefotaxime on neutrophil functions in vitro were investigated. The in vivo effects of intramuscular injection of 1 g cefotaxime on mitogen-induced lymphocyte transformation as well as neutrophil functions were also studied. Cefotaxime in vitro significantly inhibited migration of neutrophils towards endotoxin-activated serum at a concentration of 10(-3)M and towards the synthetic chemotactic tripeptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine at a concentration of greater than 10(-5)M. Post-phagocytic hexose-monophosphate shunt activity was unaffected in vitro by cefotaxime. Post-phagocytic myeloperoxidase-mediated iodination, however, was inhibited only a concentration of 10(-3)M. In vivo studies before and after injection of therapeutic doses of cefotaxime caused no changes in neutrophil functions, but injection of cefotaxime showed that the drug binds to neutrophils. This was confirmed by assaying cefotaxime levels before and after addition of the drug to neutrophils. The neutrophils also released the bound antibiotic, which retained bactericidal activity.