Dual Mechanism of Interleukin-3 Receptor Blockade by an Anti-Cancer Antibody

  • Sophie E. Broughton
  • , Timothy R. Hercus
  • , Matthew P. Hardy
  • , Barbara J. McClure
  • , Tracy L. Nero
  • , Mara Dottore
  • , Huy Huynh
  • , Hal Braley
  • , Emma F. Barry
  • , Winnie L. Kan
  • , Urmi Dhagat
  • , Pierre Scotney
  • , Dallas Hartman
  • , Samantha J. Busfield
  • , Catherine M. Owczarek
  • , Andrew D. Nash
  • , Nicholas J. Wilson
  • , Michael W. Parker
  • , Angel F. Lopez

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

Interleukin-3 (IL-3) is an activated Tcell product that bridges innate and adaptive immunity and contributes to several immunopathologies. Here, we report the crystal structure of the IL-3 receptor α chain (IL3Rα) in complex with the anti-leukemia antibody CSL362 that reveals the N-terminal domain (NTD), a domain also present in the granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-5, and IL-13 receptors, adopting unique "open" and classical "closed" conformations. Although extensive mutational analyses of the NTD epitope of CSL362 show minor overlap with the IL-3 binding site, CSL362 only inhibits IL-3 binding to the closed conformation, indicating alternative mechanisms for blocking IL-3 signaling. Significantly, whereas "open-like" IL3Rα mutants can simultaneously bind IL-3 and CSL362, CSL362 still prevents the assembly of a higher-order IL-3 receptor-signaling complex. The discovery of open forms of cytokine receptors provides the framework for development of potent antibodies that can achieve a "double hit" cytokine receptor blockade.

Original languageEnglish
Pages (from-to)410-419
Number of pages10
JournalCell Reports
Volume8
Issue number2
DOIs
Publication statusPublished or Issued - 24 Jul 2014
Externally publishedYes

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology

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