PYROGENIC ACTIVITY OF HUMAN NATIVE AND RE COMBINANT INTERLEUKINS-1-BETA

Comparative doses (100-180 ng/kg) of highly purified human native inte rleukin-1beta (nIL-1beta) and human recombinant IL-1beta (rIL-1beta) i ntravenously injected were found to cause similar changes in body temp erature in rabbits. Under these conditions, stabilization of RIL-1beta by human serum albumin (HSA) fails to affect rIL-1beta pyrogenic acti vity. nIL-1beta, 0.05-2.0 ng, injected into the PO/AH region of the br ain causes dose-dependent fever in the animals. With intrahypothalamic nIL-1beta (versus i.v. injection), the pyrogenic activity of ril-1bet a is much lower than that of nIL-1beta. Moreover, pyrogenicity appears to be dependent on the type of rIL-1beta, namely on free or stabilize d by HSA. The former has about 100-fold and the latter a 25-fold lower activity than the native cytokine (in terms of a dose-pyrogenic effec t relationship). The findings are discussed in the light of the exista nce of various interleukin IL-1beta pools.