INTERLEUKIN-1 BINDING TO ITS TYPE-I, BUT NOT TYPE-II RECEPTOR, MODULATES THE IN-VIVO ACUTE-PHASE RESPONSE

Neutralizing monoclonal antibodies against the murine interleukin 1 (I L-1) type I (mAb 35F5) and type II receptor (mAb 4E2) were used to pas sively immunize mice prior to exogenous murine IL-alpha administration or a sterile-turpentine induced abscess. When mice were passively imm unized with 35F5, the anorexia, weight loss and increased plasma acute phase protein levels in response to exogenous IL-1 alpha administrati on or a turpentine abscess were significantly attenuated. In contrast, passive immunization,vith 4E2 had only variable effects on food intak e, body weight and the hepatic acute phase response in mice administer ed IL-1 alpha. In mice following a turpentine abscess, type II recepto r blockade (4E2) either had no effect, or in some cases, actually incr eased the plasma IL-6 and acute phase protein responses. We conclude t hat in response to a turpentine abscess, the anorexia, weight loss and the induction of several hepatic acute phase reactants result in part from IL-1 binding to its type I receptor, Binding of IL-1 to the type II IL-1 receptor does not appear to be involved in the induction of t hese host nonspecific responses to inflammation. (C) 1995 Academic Pre ss Limited.