THE ABILITY OF MURINE LEUKOCYTES TO BIND LIPOCORTIN-1 IS LOST DURING ACUTE-INFLAMMATION

Lipocortin 1, a member of the annexin superfamily of calcium and phospholipid binding proteins, mediates some of the anti-inflammatory actions of the glucocorticoid hormones. Lipocortin 1 binds to the surface of murine peripheral blood monocytes and polymorpho-nuclear leukocytes (Kd estimate 2 x 10-8M) but not lymphocytes. Resident peritoneal macrophages exhibit binding (Kd estimate 1.3 x 10-8M) but lymphocytes do not. A 95 - 98% reduction in lipocortin 1 binding was observed to leukocytes obtained from air pouch or peritonitis models of inflammation. When given intravenously, lipocortin 1 binds rapidly to murine leukocytes within 5 min but disappears before 10 min, leaving the binding capacity of the cells unaltered. Modulation of lipocortin 1 binding sites could be an important step in regulating the function of inflammatory cells. © 1993 Academic Press, Inc.