MODERATE INHIBITORY EFFECT OF INTERLEUKIN-10 ON HUMAN NEUTROPHIL AND MONOCYTE CHEMOTAXIS IN-VITRO

Neutrophils and monocytes are the major classes of phagocytes that mig rate from the blood stream and accumulate in inflammed tissues in resp onse to various chemoattractants. Because IL-10 is a potent anti-infla mmatory cytokine, we analyzed its in vitro effect on chemotaxis using an under agarose method. We found that, as compared to prednisolone, I L-10 alone was a modest inhibitor of C5a, fMLP and IL-8-induced neutro phil chemotaxis, and C5a-induced monocyte chemotaxis, However, GM-CSF pretreatment of the cells potentiated this inhibitory effect, Similarl y, the IL-10 induced modulation of the beta 2 integrin CD11b/CD18 adhe sion molecule expression was only observed on GM-CSF-preactivated neut rophils and monocytes, Taken together, these results suggest that the migration and accumulation of phagocytes at infection sites would not be significantly affected by IL-10 given as an immunomodulatory therap y.