Table 1.
Surface plasmon resonance showed the binding of most anti-CTLA-4 compounds to purified CTLA-4 protein.
| Immobilization Level (RUs) | Compound | Compound Concentration (μM) | KD (µM) | Rmax (RUs) | Chi2 (RUs2) |
|---|---|---|---|---|---|
| 9476.7 | A9 | 100–1.563 | 4.16 × 105 | 15.7 | 0.27 |
| 9476.7 | D7 | 100–1.563 | 4.80 × 104 | 75.5 | 0.011 |
| 9476.7 | D11 | 100–1.563 | 4.50 × 105 | 11.3 | 0.95 |
| 10354.7 | A6 | 100–0.781 | No binding | ||
| 1034.7 | B10 | 100–0.781 | 2.13 × 104 | 32.82 | 0.87 |
Chi2; CTLA-4, cytotoxic T-lymphocyte–associated protein 4; KD, dissociation constant; Rmax, maximal response when all ligand is occupied; RUs, relative units.
KD concentration values evaluate binding between pure CTLA-4 protein and CTLA-4 inhibitors. Binding values were measured for the top hit compounds using the surface plasmon resonance method. CTLA-4 is immobilized onto the CM5 sensor chip. The steady-state affinity model or 1:1 binding model was used to measure the binding affinity and/or kinetics.