Interleukin-1β production in vivo and in vitro in rats and mice measured using specific immunoradiometric assays

Abstract

ABSTRACT Activated cells of the monocyte—macrophage lineage produce two forms of the inflammatory cytokine interleukin-1 (IL-1), IL-1α and IL-1β, of which IL-1β is the predominant secreted form and has a wide range of modulatory effects on the endocrine system. Immunoassays of human IL-1β have been described, but are not suitable for measurement of rat and mouse IL-1β because of limited cross-reactivity. Polyclonal sheep anti-rat or sheep anti-mouse IL-1β antisera were used to develop sensitive and specific immunoradiometric assays for rat and mouse IL-1β. Secretion of IL-1β from endotoxin-activated monocytes or macrophages was measured in vitro or in vivo in both species. In vitro, rat monocytes and mouse macrophages produced IL-1β in response to endotoxin, with a relatively small proportion of total IL-1β being secreted. In vivo, endotoxin stimulated an increase in plasma IL-1β in both animals. The development of these assays will facilitate studies of the role of endogenous IL-1β in animal endocrine models.