Background: Active peptides produced by monocytes, in response to endotoxin, initiate and maintain the acute phase of inflammatory response. Some antibiotics have been reported to have immunomodulatory effects in addition to their antimicrobial activity. We examined the effect of linezolid on cytokine synthesis.
Methods: The modulatory effects of erythromycin and linezolid were evaluated in LPS-stimulated human peripheral blood mononuclear cells (PBMCs). Blood was obtained by venipuncture from healthy donor volunteers. PBMCs were separated by Ficoll-Paque. More than 90% of the cells were monocytes as determined by esterase staining. Cells were incubated in the presence of LPS, with or without various concentrations of erythromycin and linezolid. The concentration of each cytokine was determined by ELISA with commercially available reagents.
Results: The two drugs suppressed significantly the synthesis of the cytokines tested in a concentration-dependent manner.
Conclusions: These data indicate that antibacterial agents may modify acute phase inflammatory response through their effects on cytokines synthesis by monocytes.