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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Antibodies, Monoclonal / chemistry
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Antibodies, Monoclonal / pharmacology*
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Antibodies, Monoclonal / therapeutic use
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Antibody Affinity
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Antibody Specificity
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Binding Sites, Antibody
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Enzyme-Linked Immunosorbent Assay
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Epitope Mapping
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Humans
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Immunoglobulin Fab Fragments / chemistry
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Immunoglobulin Fab Fragments / metabolism
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Immunoglobulin G / chemistry
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Immunoglobulin G / metabolism
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Immunoglobulin Variable Region / chemistry
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Immunologic Techniques
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Interferon-gamma / biosynthesis
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Interleukin-18 / antagonists & inhibitors
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Interleukin-18 / immunology*
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Interleukin-18 / metabolism
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Interleukin-18 Receptor alpha Subunit
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Molecular Sequence Data
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Peptide Library
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Receptors, Interleukin / antagonists & inhibitors
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Receptors, Interleukin / metabolism
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Receptors, Interleukin-18
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Signal Transduction / drug effects
Substances
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Antibodies, Monoclonal
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IL18R1 protein, human
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Immunoglobulin Fab Fragments
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Immunoglobulin G
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Immunoglobulin Variable Region
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Interleukin-18
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Interleukin-18 Receptor alpha Subunit
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Peptide Library
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Receptors, Interleukin
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Receptors, Interleukin-18
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Interferon-gamma