Development and application of a radioimmunoassay to detect interleukin-1 in rat peripheral circulation.
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.
Derijk
R
R
Department of Pharmacology, Medical Faculty, Free University, Amsterdam, The Netherlands.
Berkenbosch
F
F
D000818:Animals; D000906:Antibodies / Q000276:immunology; D002845:Chromatography; D006801:Humans; D007375:Interleukin-1 / Q000097:blood* / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism; D011863:Radioimmunoassay / Q000379:methods*; D051381:Rats / Q000097:blood*; D011994:Recombinant Proteins; D017186:Titrimetry
D000906:Antibodies; D007375:Interleukin-1; D008070:Lipopolysaccharides; D011994:Recombinant Proteins