TRAIL-R1 and TRAIL-R2 scFv antagonise TRAIL binding to either TRAIL-R1 and/or TRAIL-R2. Example data demonstrating that (A) binding of TRAIL to TRAIL-R1 and (B) binding of TRAIL to TRAIL-R2 can be inhibited by increasing concentrations of different TRAIL-R1 scFv (T1-1, T1-2, T1-3 and T1-7), TRAIL-R2 scFv (T2-1, T2-2, T2-3 and T2-7) and one TRAIL-R1/-R2 cross-reactive scFv (X1-1) (IC50s shown).