In order to define the inhibitory activity of PMN-Ectosomes, we investigated the early gene expression profiles of resting and zymosan A-stimulated human monocyte-derived macrophages in the absence or presence of PMN-Ectosomes. Overall design: We cultured monocytes isolated from fresh buffy coats of 4 healthy donors (2 males and 2 females between the ages of 20 to 45) for 7 days at 37°C. At day 7, macrophages were cultured for another 3 hours alone, in presence of PMN-Ectosomes, with zymosan A, and with zymosan A and PMN-Ectosomes.