Development and application of a radioimmunoassay to detect interleukin-1 in rat peripheral circulation

Publication Type:

Journal Article


Am J Physiol Endocrinol Metab, Volume 263, Number 6, p.E1092-E1098 (1992)


Animals; Antibodies; blood; Chromatography; Humans; immunology; Interleukin-1; Lipopolysaccharides; Macrophages; metabolism; methods; Netherlands; pharmacology; Proteins; Radioimmunoassay; RAT; Rats; Recombinant Proteins; Time; Titrimetry


We describe the development and application of a radioimmunoassay to detect circulating interleukin (IL)-1 beta concentrations in the rat. No IL-1 immunoreactivity above the detection limit of the assay (100 pg/ml) could be detected in plasma of control rats. In contrast, immunoreactive IL-1 was detected after intravenous administration of rat recombinant IL-1 beta (rrIL-1 beta) or bacterial lipopolysaccharide (LPS) to rats. The effect of LPS on plasma immunoreactive IL-1 concentrations was time and dose dependent. The immunoreactive IL-1 response to LPS was prevented by in vivo macrophage depletion induced by liposome-directed macrophage suicide technique. Gel filtration of plasma from LPS-treated rats revealed the presence of a high and a smaller molecular form of immunoreactive IL-1. The small molecular immunoreactive IL-1 peak coeluted with rrIL-1 beta and probably represents the 17-kDa form of IL-1 beta. In conclusion, our data support the hypothesis that IL-1 secreted by macrophages can act as a humoral signal molecule to induce the immunological, metabolic, and neuroendocrine changes in response to bacterial LPS