Generation and characterization of antagonistic anti-human interleukin (IL)-18 monoclonal antibodies with high affinity: Two types of monoclonal antibodies against full-length IL-18 and the neoepitope of inflammatory caspase-cleaved active IL-18

• Published in: Archives of biochemistry and biophysics Vol. 663; pp. 71 - 82
• Main Authors: Nariai, Yuko, Kamino, Hiroki, Obayashi, Eiji, Kato, Hiroaki, Sakashita, Gyosuke, Sugiura, Tomoko, Migita, Kiyoshi, Koga, Tomohiro, Kawakami, Atsushi, Sakamoto, Kazuma, Kadomatsu, Kenji, Nakakido, Makoto, Tsumoto, Kouhei, Urano, Takeshi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-03-2019
• Subjects: Antibodies, Monoclonal - biosynthesis; Antibodies, Monoclonal - immunology; Antibody Affinity; Caspases - metabolism; Cell Line, Tumor; HEK293 Cells; Humans; Inflammation Mediators - immunology; Inflammation Mediators - metabolism; Interferon-gamma - metabolism; Interleukin-18 - immunology; Interleukin-18 - metabolism; Proteolysis
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/j.abb.2019.01.001

Interleukin‐18 (IL‐18) is a pro-inflammatory cytokine that evokes both innate and acquired immune responses. IL-18 is initially synthesized as an inactive precursor and the cleavage for processing into a mature, active molecule is mediated by pro-inflammatory caspases following the activation of inflammasomes. Two types of monoclonal antibodies were raised: anti-IL-1863−68 antibodies which recognize full-length1−193 and cleaved IL-18; and anti-IL-18 neoepitope antibodies which specifically recognize the new N-terminal 37YFGKLESK44 of IL-18 cleaved by pro-inflammatory caspase-1/4. These mAbs were suitable for Western blotting, capillary Western immunoassay (WES), immunofluorescence, immunoprecipitation, and function-blocking assays. WES analysis of these mAbs allowed visualization of the IL-18 bands and provided a molecular weight corresponding to the pro-inflammatory caspase-1/4 cleaved, active form IL-1837−193, and not to the inactive precursor IL-18, in the serum of patients with adult-onset Still's disease (6/14, 42%) and hemophagocytic activation syndrome (2/6, 33%). These monoclonal antibodies will be very useful in IL-18 and inflammasome biology and for diagnostic and therapeutic strategies for inflammatory diseases.
•mAb 11–4.1 recognized full-length and cleaved IL-18 with high affinity.•mAb 9–10.2 specifically recognized inflammatory caspase-cleaved IL-18 with high affinity.•The newly generated mAbs visualized the IL-18 bands in the serum of inflammatory patients.•The newly generated mAbs antagonized IL-18.