Human neutrophil defensins selectively chemoattract naive T and immature dendritic cells

Defensins, a family of cationic, structurally related, antimicrobial peptid es, contribute to host defense by disrupting the cytoplasmic membrane of mi crobes, Here we show that human neutrophil defensins selectively induce the migration of human CD4(+)/CD45RA(+) naive and CD8(+), but not CD4(+)/CD45R O(+) memory, T cells. Moreover, hunan neutrophil defensins are chemotactic for immature human dendritic cells derived from either CD34(+) progenitors or peripheral blood monocytes. Upon maturation induced by treatment with tu mor necrosis factor alpha (TNF-alpha), dendritic cells lose their responsiv eness to human neutrophil defensins. The chemotactic effect of human neutro phil defensins on both T and dendritic cells is pertussis toxin-sensitive s uggesting that a G(i alpha) protein-coupled receptor is responsible. Human neutrophil defensins are also chemotactic for immature murine dendritic cel ls, These data suggest that, in addition to their antimicrobial role, human neutrophil defensins also contribute to adaptive immunity by mobilizing T cells and dendritic cells.