Effect of proinflammatory cytokines on the interplay between roxithromycin, HMR 3647, or HMR 3004 and human polymorphonuclear neutrophils

Cytokines, the hallmarks of infectious and inflammatory diseases, modify ph agocyte activities and thus may interfere with the immunomodulating propert ies of antibacterial agents. We have investigated whether various proinflam matory cytokines (interleukin 1 [IL-1], IL-6, IL-8, gamma interferon, tumor necrosis factor alpha [TNF-alpha], and granulocyte-macrophage colony-stimu lating factor [GM-CSF]) modify two macrolide properties, i.e., inhibition o f oxidant production by polymorphonuclear neutrophils (PMN) and cellular up take. Roxithromycin and two ketolides, HMR 3647 and HMR 3004, were chosen a s the test agents. TNF-alpha and GM-CSF (but not the other cytokines) decre ased the inhibitory effect of HMR 3647 only on oxidant production by PMN, F ifty percent inhibitory concentrations were, however, in the same range in control and cytokine-treated cells (about 60 to 70 mu g/ml), suggesting tha t HMR 3647 acts downstream of the priming effect of cytokines, In contrast, the impairment of oxidant production by roxithromycin and HMR 3004 was unc hanged (or increased) in cytokine-treated cells. This result suggests that HMR 3004 (the strongest inhibitory drug, Likely owing to its quinoline side chain) and roxithromycin act on a cellular target upstream of cytokine act ion. In addition, TNF-alpha and GM-CSF significantly (albeit moderately) im paired (by about 20%) the uptake of the three molecules by PMN, The inhibit ory effect of these two cytokines seems to be related to activation of the p38 mitogen-activated protein kinase. Our data also illuminate the mechanis m underlying macrolide uptake: protein kinase A- and tyrosine kinase-depend ent phosphorylation seems to be necessary for optimal uptake, while protein kinase C activation impairs it. The relevance of our data to the clinical setting requires further investigations, owing to the complexity of the cyt okine cascade during infection and inflammation.