PLASMINOGEN DEFICIENCY DIFFERENTIALLY AFFECTS RECRUITMENT OF INFLAMMATORY CELL-POPULATIONS IN MICE

It is widely held that the plasminogen (Pig) system plays a role in in flammation through plasmin-mediated directional cell migration. Howeve r, substantial evidence for its involvement in the inflammatory respon se has been obtained from indirect studies and lacks firm biological c onfirmation. To directly characterize plasminogen's involvement in the inflammatory response, we used thioglycollate to induce a peritoneal inflammatory reaction in PIS(+/+), Plg(+/-), and Plg(-/-) mice. At 6 h ours poststimulation, neutrophil recruitment into the peritoneum was m aximal and similar between Plg(+/+), Plg(+/-), and Plg(-/-) mice. In c ontrast, monocyte recruitment was significantly diminished after 24 ho urs poststimulation in Plg(-/-) mice relative to Plg(+/+) mice, Lympho cyte recruitment also was blunted. Blood monocyte levels in these mice indicated that diminished recruitment into the peritoneum was not the result of a diminished source of cells in the circulation, Macrophage phagocytic function was similar between Plg(+/+) and Plg(-/-) mice, T his study establishes a direct involvement of plasminogen in monocyte recruitment during a representative inflammatory response. (C) 1998 by The American Society of Hematology.