title: Development of isoform-specific monoclonal antibodies against human IL-18 binding protein.
abstract: Interleukin-18 binding protein (IL-18BP) is a soluble antagonist of IL-18 originally discovered while attempting to isolate a soluble receptor by using IL-18-ligand affinity column. IL-18BP has four isoforms (a, b, c, and d) in humans and two isoforms (c and d) in mice. The human isoforms IL-18BPa and IL-18BPc neutralize IL-18 activity sufficiently at an equimolar ratio; however IL-18BPb and IL-18BPd isoforms lack a complete Ig domain at C-terminus and lose the ability to neutralize IL-18 activity. Mouse IL-18BPc and IL-18BPd isoforms, possessing a similar complete Ig domain, also neutralize the biological activity of mouse IL-18 at an equimolar ratio. Here we expressed recombinant proteins of the active human IL-18BP isoforms and developed monoclonal antibodies (MAbs) against human IL-18BP a and c isoforms. We obtained two MAbs (78-4 and 38-3) of human IL-18BPa and two MAbs (18-7 and 29-6) of human IL-18BPc. The MAb clones 18-7 and 29-6 specifically recognized recombinant IL-18BPc in Western blot analyses and ELISA, whereas the MAb clone 78-4 recognized both isoforms in Western blot analyses, but only human IL-18BPa isoform in ELISA. We developed a sandwich ELISA by using the monoclonal antibody specific to human IL-18BPa isoform. The isoform-specific anti-human IL-18BP MAb may be a useful tool in categorizing a distinct group of patients from various autoimmune diseases related to IL-18BP.
authors.affiliation: Department of Immunology, College of Medicine, Konkuk University, Chungju City, Chungbuk, Korea.
authors.forename: Siyoung
authors.initials: S
authors.lastname: Lee
authors.forename: Sunjong
authors.initials: S
authors.lastname: Kim
authors.forename: Suyoung
authors.initials: S
authors.lastname: Bae
authors.forename: Jida
authors.initials: J
authors.lastname: Choi
authors.forename: Jaewoo
authors.initials: J
authors.lastname: Hong
authors.forename: Soyoon
authors.initials: S
authors.lastname: Ryoo
authors.forename: Hyunjhung
authors.initials: H
authors.lastname: Jhun
authors.forename: Kwangwon
authors.initials: K
authors.lastname: Hong
authors.forename: Eunsom
authors.initials: E
authors.lastname: Kim
authors.forename: Seunghyun
authors.initials: S
authors.lastname: Jo
authors.forename: Erk
authors.initials: E
authors.lastname: Her
authors.forename: Soohyun
authors.initials: S
authors.lastname: Kim
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis* / Q000276:immunology* / Q000302:isolation & purification; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D020033:Protein Isoforms / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D036341:Intercellular Signaling Peptides and Proteins; D020033:Protein Isoforms; C118370:interleukin-18 binding protein