Structure-based Development of Human Interleukin-1β-Specific Antibody That Simultaneously Inhibits Binding to Both IL-1RI and IL-1RAcP

J Mol Biol. 2021 Feb 19;433(4):166766. doi: 10.1016/j.jmb.2020.166766. Epub 2020 Dec 24.

Abstract

Interleukin-1β (IL-1β) is a potent pleiotropic cytokine playing a central role in protecting cells from microbial pathogen infection or endogenous stress. After it binds to IL-1RI and recruits IL-1 receptor accessory protein (IL-1RAcP), signaling culminates in activation of NF-κB. Many pathophysiological diseases have been attributed to the derailment of IL-1β regulation. Several blocking reagents have been developed based on two mechanisms: blocking the binding of IL-1β to IL-1RI or inhibiting the recruitment of IL-1RAcP to the IL-1β initial complex. In order to simultaneously fulfill these two actions, a human anti-IL-1β neutralizing antibody IgG26 was screened from human genetic phage-display library and furthered structure-optimized to final version, IgG26AW. IgG26AW has a sub-nanomolar binding affinity for human IL-1β. We validated IgG26AW-neutralizing antibodies specific for IL-1β in vivo to prevent human IL-1β-driving IL-6 elevation in C56BL/6 mice. Mice underwent treatments with IgG26AW in A549 and MDA-MB-231 xenograft mouse cancer models have also been observed with tumor shrank and inhibition of tumor metastasis. The region where IgG26 binds to IL-1β also overlaps with the position where IL-1RI and IL-1RAcP bind, as revealed by the 26-Fab/IL-1β complex structure. Meanwhile, SPR experiments showed that IL-1β bound by IgG26AW prevented the further binding of IL-1RI and IL-1RAcP, which confirmed our inference from the result of protein structure. Therefore, the inhibitory mechanism of IgG26AW is to block the assembly of the IL-1β/IL-1RI/IL-1RAcP ternary complex which further inhibits downstream signaling. Based on its high affinity, high neutralizing potency, and novel binding epitope simultaneously occupying both IL-1RI and IL-1RAcP residues that bind to IL-1β, IgG26AW may be a new candidate for treatments of inflammation-related diseases or for complementary treatments of cancers in which the role of IL-1β is critical to pathogenesis.

Keywords: IL-1RAcP; IL-1RI; epitope mapping; human interleukin-1β; therapeutic antibody.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Blocking / chemistry*
  • Antibodies, Monoclonal / chemistry*
  • Antineoplastic Agents, Immunological / chemistry
  • Antineoplastic Agents, Immunological / pharmacology
  • Binding Sites
  • Cell Line, Tumor
  • Epitope Mapping / methods
  • Epitopes / immunology
  • Humans
  • Immunoglobulin G / chemistry
  • Interleukin-1 Receptor Accessory Protein / chemistry*
  • Interleukin-1 Receptor Accessory Protein / metabolism
  • Interleukin-1beta / chemistry*
  • Interleukin-1beta / metabolism
  • Mice
  • Models, Biological
  • Models, Molecular*
  • NF-kappa B / metabolism
  • Peptide Library
  • Protein Binding / drug effects
  • Protein Conformation*
  • Receptors, Interleukin-1 Type I / chemistry*
  • Receptors, Interleukin-1 Type I / metabolism
  • Signal Transduction
  • Structure-Activity Relationship
  • Xenograft Model Antitumor Assays

Substances

  • Antibodies, Blocking
  • Antibodies, Monoclonal
  • Antineoplastic Agents, Immunological
  • Epitopes
  • IL1B protein, human
  • IL1RAP protein, human
  • Immunoglobulin G
  • Interleukin-1 Receptor Accessory Protein
  • Interleukin-1beta
  • NF-kappa B
  • Peptide Library
  • Receptors, Interleukin-1 Type I