Interleukin-3 (IL-3) is an activated T cell product that bridges innate and adaptive immunity and contributes to several immunopathologies. Structure of IL-3 receptor alpha chain (IL3Ra) in complex with the anti-leukemia antibody CSL362 reveals that the N-terminal domain (NTD), a domain also present in the granulocyte-macrophage colony-stimulating factor (GM-CSF), contains the CSL362 binding epitope. Furthermore, NTD of IL3Ra adopts a typical fibronectin type III (FnIII) fold [1].

1: Dual mechanism of interleukin-3 receptor blockade by an anti-cancer antibody. Broughton SE, Hercus TR, Hardy MP, McClure BJ, Nero TL, Dottore M, Huynh H, Braley H, Barry EF, Kan WL, Dhagat U, Scotney P, Hartman D, Busfield SJ, Owczarek CM, Nash AD, Wilson NJ, Parker MW, Lopez AF; Cell Rep. 2014;8:410-419. PMID:25043189