Absence of Pyrogenicity by Urinary IL-1 Activity

Abstract

Normal human urine contains low molecular weight fractions of approximately 2000, 4000 and 15 000 mol wt which are active in the mouse thymocyte comitogen assay (LAF assay) and in the human dermal fibroblast proliferation assay, and which therefore are possibly related to interleukm-1 (IL-1). Additional biological propertiesof the urinary lymphocyte activating factor (LAF) activity which were examined were pyrogenicity and their antigenic similarity with endogenous pyrogen Urine concentrates were chromatographed over S-200 and fractions were analysed for LAF activity in the presence or absence of an antiserum against human endogenous pyrogen (EP). LAF activity in these fractions was not inhibited by the antiserum. Peak fractions were also tested for fever induction in C3H/HeJ mice and no increases in rectal temperatures were observed. These results suggest that the lymphoprolifcrative and pyrogenic properties of IL-1/EP or IL-1 related substances are not necessarily contained in the same chemical moiety but may be carried in different portions of the molecule. The fact that the 15K urinary LAF is also non-pyrogenic suggests that either it has lost those determinants which regulate pyrogenicity or that this 15K activity is not derived from cells which produce LAF/EP.