LIMITED INFLUENCE OF THE MESOTHELIUM ON THE INFLUX OF MONOCYTES INTO THE PERITONEAL-CAVITY

We have investigated the role of human mesothelium in an in vitro mode l of peritonitis on the monocyte adherence to and migration across mon olayers of peritoneal mesothelial cells. Monocytes adhere avidly to no n-activated mesothelial cell monolayers; however, migration in this si tuation was minimal. Prestimulation of the monolayers with IL-1 beta d id not alter these results. Anti-CD18 and anti-VLA-4 mAbs used in comb ination had an additive inhibitory effect on monocytes adherence to re sting or IL-1 beta-pretreated mesothelial cells, MCP-1 and TGF-beta ar e secreted by mesothelial cells. Both have a modest role in mesotheliu m-induced monocyte chemotaxis: mAbs against these cytokines had an add itive inhibitory effect on the chemotaxis induced by supernatant from 24-h prestimulated mesothelial cells. Our results indicate that the me sothelium itself has a limited role in the influx of monocytes into th e peritoneal cavity during the onset of peritonitis.