Plot of GMCSF receptors/cell (measured at ligand concentration of 0.7 nmol/L) versus IC₅₀ for DT388–GM-CSF (concentration of drug inhibiting cell protein synthesis by 50%). Linear regression performed yielded log (IC₅₀ ) = 0.11*(GM-CSF receptor occupancy at 0.7 nmol/L) + 3.806 with r² = .557.