BIAcore analysis of super-agonistic IL-4 variants. BIAcore sensorgrams of ligand receptor interactions. Solutions of the indicated IL-4 variants (concentration 10 nM) were perfused over a sensor chip with immobilized IL4RαECD. (a) Compared to wild-type IL-4 (green) the super-agonistic variants IL4-T13D (red) and IL4-F82D (cyan) show higher binding-affinities to IL4RαECD owing to an approximately 3 times slower dissociation rate k
off. (b) The double variant IL4-T13D-F82D (purple) shows no altered binding-affinity to IL4RαECD in comparison to wild-type IL-4 (green).