“…Abbreviations used in this paper: Con A, concanavalin A; DME, Dulbecco's modified Eagles medium; hrIL-l ,B, human recombinant IL-I f,; IL-1, interleukin 1; LAF, lymphocyte-activating factor; MCF, mononuclear cell factor; PGE2, prostaglandin E2-glandin E2 (PGE2) and collagenase, both of which reflect mechanisms of tissue destruction (4)(5)(6)(7)(8). IL-1 has been found in synovial fluid (9,10), serum (11,12), and urine (13,14). However, the control of IL-I activities and its regulation in vivo is poorly understood.…”