title: Species differences in [125I]interleukin-1 binding in brain, endocrine and immune tissues.
abstract: There were dramatic species differences in the level of [125I]recombinant human interleukin-1 alpha ([125I]hIL-1 alpha) binding with high levels of binding present in mouse and rabbit tissues, while no specific binding was present in rat and guinea pig tissues. Utilizing [125I]hIL-1 alpha, moderate to high levels of specific binding were observed in EL-4 6.1 cells (representative of Type I IL-1 receptors) and in mouse hippocampus, spleen and testis; however, no specific [125I]hIL-1 alpha binding was present in Raji cells (representative of Type II IL-1 receptors) and in rat tissues. On the other hand, utilizing [125I]hIL-1 beta, high specific IL-1 binding was present in EL-4 6.1 and Raji cells and moderate binding was evident in mouse tissues, whereas specific [125I]hIL-1 beta binding to rat tissues was not detectable. Moreover, no IL-1 binding in rat tissues was observed using [125I]hIL-1 receptor antagonist, [125I]mouse IL-1 beta or the homologous radioligands [125I]rat IL-1 beta or [125I]rat IL-1 receptor antagonist. These data demonstrate that under optimal conditions for labeling Type I or Type II IL-1 receptors, no specific binding is observed in rat tissues suggesting the presence of novel IL-1 receptor(s) in rat tissues.
authors.affiliation: Central Nervous System Diseases Research, DuPont Merck Pharmaceutical Co., Wilmington, DE 19880-0400.
authors.forename: T
authors.initials: T
authors.lastname: Takao
authors.forename: R C
authors.initials: RC
authors.lastname: Newton
authors.forename: E B
authors.initials: EB
authors.lastname: De Souza
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D006168:Guinea Pigs; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008024:Ligands; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009928:Organ Specificity; D011817:Rabbits; D051381:Rats; D017472:Receptors, Interleukin-1 / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013045:Species Specificity; D013154:Spleen / Q000378:metabolism*; D013737:Testis / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D007375:Interleukin-1; D007457:Iodine Radioisotopes; D008024:Ligands; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins