Immunoprecipitation of interleukin-1 receptors from a mouse thymoma cell line, EL-4

Receptors for the monokine, interleukin-1 (IL-1), have been successfully immunoprecipitated with a xenogeneic antiserum raised in our laboratories. Receptors solubilized from mouse cell membranes as well as nascent chains of molecules that could bind IL-1 were immunoprecipitated. Receptor complexes were identified on mouse cell lines which express IL-1 receptors by affinity cross-linkage of the radiolabeled ligands, IL-1-α or IL-1-β. Soluble IL-1 or IL-1 nonspecifically associated with membranes of cells which do not express IL-1 receptors was not immunoprecipitated. It is apparent, thus, that antibodies present in the xenogeneic antiserum could specifically bind to the IL-1 receptor moiety within the complex. The major proportion of IL-1 receptor complexes that were reproducibly immunoprecipitated had a molecular weight of 97,000. Cell membrane associated receptors for the monokine, tumor necrosis factor, were not immunoprecipitated. These antibodies have contributed to the understanding of the role of IL-1 receptors in cytolytic effector T cell generation and should contribute further in the purification and characterization of the IL-1 receptor moiety, as well as in determining IL-1-mediated mechanisms of cellular activation.