Purification and Characterization of the Human Interleukin-18 Receptor

• Published in: The Journal of biological chemistry 1997-10, Vol.272 (41), p.25737-25742
• Main Authors: Torigoe, Kakuji, Ushio, Shimpei, Okura, Takanori, Kobayashi, Susumu, Taniai, Madoka, Kunikata, Toshio, Murakami, Tadatoshi, Sanou, Osamu, Kojima, Hirotada, Fujii, Mitsukiyo, Ohta, Tsunetaka, Ikeda, Masao, Ikegami, Hakuo, Kurimoto, Masashi
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antibodies, Monoclonal; Cell Membrane - chemistry; COS Cells; Cytokines - metabolism; Hodgkin Disease - metabolism; Humans; Interleukin-1 - metabolism; Interleukin-18; Interleukin-18 Receptor alpha Subunit; Kinetics; Mice; Mice, Inbred BALB C; Molecular Sequence Data; NF-kappa B - metabolism; Receptors, Interleukin - chemistry; Receptors, Interleukin - isolation & purification; Receptors, Interleukin-18; Tumor Cells, Cultured
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.272.41.25737

Interleukin (IL)-18 was identified as a molecule that induces IFN-γ production and enhances NK cell cytotoxicity. In this paper, we report upon the purification and characterization of human IL-18 receptor (hIL-18R). We selected the Hodgkin's disease cell line, L428, as the most strongly hIL-18R-expressing cell line based on the results of binding assays. This binding was inhibited by IL-18 but not by IL-1β. The dissociation constant (Kd) of125I-IL-18 binding to L428 cells was about 18.5 nm, with 18,000 binding sites/cell. After immunizing mice with L428 cells and cloning, a single monoclonal antibody (mAb) against hIL-18R was obtained (mAb 117-10C). Sequentially, hIL-18R was purified from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS)-extracted L428 cells by wheat germ lectin-Sepharose 4B chromatography and mAb 117-10C-Sepharose chromatography. The internal amino acid sequences of hIL-18R all matched those of human IL-1 receptor-related protein (IL-1Rrp), the ligand of which was unknown to date. When expressed in COS-1 cells, the cDNA of IL-1Rrp conferred IL-18 binding properties on the cells and the capacity for signal transduction. From these results, we conclude that a functional IL-18 receptor component is IL-1Rrp.