title: Human anti-human IL-18 antibody recognizing the IL-18-binding site 3 with IL-18 signaling blocking activity.
abstract: IL-18 is an important regulator in both innate and acquired immune responses. The aberrant expression of IL-18 is associated with severe inflammatory conditions, such as autoimmune diseases and allergies. Thus, human antibodies with inhibitory activity on IL-18 signaling may be useful for therapeutic applications. We report here the first establishment of an antagonistic anti-IL-18 complete human antibody, h18-108, employing a human single chain antibody (scFv)-displaying phage library. The h18-108 scFv inhibited the IFN-gamma production of a human myelomonocytic cell line, KG-1. Flow cytometry analysis showed that h18-108 blocked the binding of IL-18 to KG-1 cells. Epitope mapping analysis using two kinds of random peptide-displaying phage libraries and an IL-18 alanine mutant (D98A) demonstrated that the h18-108 scFv binds to the site 3 of IL-18, which is suggested to be an association site with the IL-18 receptor beta. The complete human Fab and IgG forms of h18-108 have been successfully constructed to attain increases in both binding affinity and inhibitory activity.
authors.affiliation: Department of Bioengineering, Faculty of Engineering, Kagoshima University, Korimoto 1-21-40, Kagoshima 890-0065, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Hamasaki
authors.forename: Shuhei
authors.initials: S
authors.lastname: Hashiguchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ito
authors.forename: Zenichiro
authors.initials: Z
authors.lastname: Kato
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nakashima
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D000915:Antibody Affinity; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000378:metabolism; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000737:chemistry; D007158:Immunologic Techniques; D007371:Interferon-gamma / Q000096:biosynthesis; D020382:Interleukin-18 / Q000037:antagonists & inhibitors / Q000276:immunology* / Q000378:metabolism; D053727:Interleukin-18 Receptor alpha Subunit; D008969:Molecular Sequence Data; D019151:Peptide Library; D018123:Receptors, Interleukin / Q000037:antagonists & inhibitors / Q000378:metabolism; D053724:Receptors, Interleukin-18; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000911:Antibodies, Monoclonal; C508572:IL18R1 protein, human; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007135:Immunoglobulin Variable Region; D020382:Interleukin-18; D053727:Interleukin-18 Receptor alpha Subunit; D019151:Peptide Library; D018123:Receptors, Interleukin; D053724:Receptors, Interleukin-18; D007371:Interferon-gamma