Biological role of the IL-1 receptor type II (IL-1RII) as defined by a monoclonal antibody

Differential effects of IL-1ra on sickness behavior and weight loss induced by IL-1 in rats

Peripheral and central injections of recombinant human interleukin-1 beta (IL-1 beta) have been shown to decrease social exploration and to induce body weight loss in rats. To characterize the receptor mechanisms of these effects, we used as a tool a specific antagonist of the receptors of IL-1, IL-1ra. Intraperitoneal (i.p.) administration of IL-1ra (8 mg/kg) blocked the effect of i.p. injection of IL-1 beta (4 micrograms/rat) on social behaviour but not on body weight. Central administration of IL-1ra (60 micrograms/rat, i.c.v.) abrogated the effects of centrally administered IL-1 beta (30 ng/rat, i.c.v.) on both social behaviour and body weight. Central injection of IL-1ra (4 micrograms/rat, i.c.v.) also attenuated the effects of i.p. administered IL-1 beta (4 micrograms/rat) on social behaviour but not on body weight. These results suggest that the effects of IL-1 beta on social behavior are mediated centrally and that its effect on the loss of body weight involves different receptor mechanisms.

Monoclonal antibody 1994-01 (also known as ALVA 42) reported to recognize type II IL-1 receptor is specific for HLA-DR alpha and beta chains

Monoclonal antibody (MAb) 1994-01 has been reported to bind to the human type II Interleukin 1 (IL-1) receptor and in so doing block IL-1 binding in vitro and certain IL-1 mediated responses in vivo. While this antibody binds to a type II IL-1 receptor positive cell line, it can be shown that it does not bind to the type II IL-1 receptor. By direct expression cloning, we have identified two gene products, both of which are required for binding of this antibody. The two proteins are the alpha and beta subunits of the MHC class II antigen HLA-DR.

Importance of brain IL-1 type II receptors in fever and thermogenesis in the rat

Interleukin-1 (IL-1) acts centrally to induce fever and thermogenesis in rodents. The central actions of IL-1 alpha and IL-1 beta apparently involve different mechanisms, and the effects of IL-1 beta are not consistent with interaction with a type I (IL-1RI) 80-kDa receptor. In the present study the involvement of the type II IL-1 receptor (IL-1RII) was tested in the rat by examining the effects of central injection of a monoclonal antibody (ALVA-42), which blocks the IL-1RII. Pretreatment of rats with ALVA-42 (6 micrograms icv) inhibited the thermogenic and pyrogenic responses to intracerebroventricular injection of 5 ng (but not 50 ng) of IL-1 beta in conscious rats but did not significantly modify responses to IL-1 alpha. ALVA-42 also failed to modify the responses to peripherally administered IL-1 beta (1 microgram) but significantly attenuated the pyrogenic and thermogenic responses to peripheral (125 micrograms) or central (1 microgram) injection of endotoxin. These data indicate that IL-1RII mediates the central effects of a low dose of IL-1 beta, but not IL-1 alpha, on fever and thermogenesis in the rat. They also imply that responses to endotoxin are due, at least in part, to the activation of IL-1RII by IL-1 beta released within the brain and that effects of peripherally injected IL-1 beta involve different mechanisms, probably associated with IL-1RI.