Figure 6. Direct inhibition of the interaction between mouse IL-2 and IL-2 receptor α chain by anti-mIL-2 antibodies. Polyvinyl chloride microtiter plates were coated with soluble receptor α chain at 2.5 µg/mL. Diluted purified phages displaying mIL-2 (10¹¹ viral particles/mL) were incubated on coated wells, after pre-incubating them in the presence or absence of competitor antibodies in solution at 1 µg/mL. 9E10 mAb was used as a control non-competitor antibody (recognizing the c-myc tag fused to IL-2 molecules in our display system). Bound phages were detected with an anti-M13 mAb conjugated to horseradish peroxidase. Arrows indicate inhibition of mIL-2 binding to the immobilized α chain.