E21R prevents formation of the ternary GM-CSF receptor complex.

Following formation of the GM-CSF/sGMRα/sβc ternary complex using a 1:2:4 molar ratio, a 100-fold molar excess of E21R over GM-CSF was added for a further hour at 25°C before size-exclusion chromatography. The chromatogram shows the A₂₈₀ profile of a GM-CSF/sGMRα/sβc mixture in the absence (thick line) or presence of E21R (thin line) or in sβc alone (dashed line).