[Human neutrophilic defensin modulates the functional activity of the monocytes]

The effects of defensin, a peptide derived from human neutrophils, on aggregation of human peripheral blood monocytes were studied. Defensin (0.01 microgram/mL--100 micrograms/mL) caused a distinct dose dependent aggregation of normal donor monocytes. In addition, defensin increased the rate of monocyte aggregation induced by arachidonic acid or phorbol myristate acetate. Additional doses of defensin added to monocytes preactivated by this peptide produced no further aggregation. These data suggest that human defensin is an important physiological mediator released by neutrophils to regulate functions of monocytes.