Figure 3. Aptamer FAIR-6 binds Hyper-IL-6 with high affinity. Filter retention assays; constant amounts (< 1 nM) of ³²P-radioactively labeled aptamer FAIR-6 (dots) and RNA starting library B50 (open circles) were incubated with increasing amounts of Hyper-IL-6 (0–500 nM). Protein-bound RNA was visualized by autoradiography. Fractions of bound RNA molecules were plotted against the concentration of Hyper-IL-6. Data points represent mean values of two independent measurements.