Molecular characterization and functional expression of equine interleukin-1 type I and type II receptor cDNAs

cDNA generated from lipopolysaccharide-stimulated equine peripheral blood mononuclear cells was used to amplify and clone type I and type II equine interleukin-1 receptors (IL-1RI and IL-1RII) using primers derived from semi-conserved regions between human and mouse IL-1RI and IL-1RII sequences, respectively. 5′ and 3′ terminal sequences of equine IL-1RI and IL-1RII were amplified by 5′ and 3′ rapid amplification of cDNA ends. The deduced amino acid sequence of equine IL-1RI demonstrated 77, 64 and 63% similarity with human, mouse and rat sequences, respectively. The predicted amino acid sequence of equine IL-1RII demonstrated 70, 60 and 58% similarity with human, mouse and rat sequences, respectively. Recombinant equine soluble IL-1RI and IL-1RII produced in insect cells bound recombinant equine IL-1α and IL-1β. Furthermore, both receptors suppressed the growth inhibitory activities of equine IL-1α and IL-1β toward A375 cells in a dose-dependent manner, indicating that the present equine IL-1RI and IL-1RII cDNA encodes biologically active proteins.