POLARIZED SECRETION OF INTERLEUKIN-8 BY HUMAN MESOTHELIAL CELLS - A ROLE IN NEUTROPHIL MIGRATION

We investigated the role of human mesothelium in an in vitro model of peritonitis with emphasis on the secretion of the neutrophil chemoattr actant interleukin-8 (IL-8) and the migration of polymorphonuclear leu cocytes (PMN) across monolayers of peritoneal mesothelial cells. PMN s howed minimal migration across non-activated mesothelial monolayers (< 2%). However, migration was induced after mesothelial cell activation by IL-1 beta (24%) and this induced migration was significantly blocke d by antibodies against IL-8 (63% inhibition; P less than or equal to 0.01). IL-beta-activated mesothelial monolayers were shown to secrete IL-8 in a polarized way, which was preferentially oriented towards the apical side of the monolayer. Our results indicate that the influx of PMN into the peritoneal cavity is, at least in part, controlled by th e mesothelial cell layer of the peritoneal membrane.