Table 1.
Kinetic constants of monoclonal antibodies (mAbs) directed against the extracellular domains of CD32B1
| CD32B | CD32A-R131 | |||||
|---|---|---|---|---|---|---|
| mAb | ka (× 10−5/m/s) | kd (× 104/s) | KD (nm) | ka (× 10−5/m/s) | kd (× 104/s) | KD (nm) |
| 2B6 | 26·1 ± 12·4 | 6·9 ± 0·9 | 0·3 ± 0·1 | ND | ND | ND |
| 3H7 | 3·8 ± 0·4 | 2·2 ± 0·3 | 0·6 ± 0·1 | ND | ND | ND |
| 1F2 | 2·7 (2·4–3·0) | 335 (300–370) | 123 (122–124) | ND | ND | ND |
| FLI8·26 | 12·9 (9·5–16·3) | 178 (150–206) | 14·3 (12·6–16·0) | 10·5 (5·4–15·6) | 31 (22–40) | 3·3 (2·5–4·2) |
| KB61 | 13·9 (13·2–14·7) | 82 (80–84) | 5·9 (6·4–5·4) | 11·5 (11·1–12·0) | 220 (212–228) | 19 (19·0–19·1) |
1
Surface plasmon resonance was used to determine the kinetic constants for CD32 binding of 2B6, 3H7 and 1F2. The pan-CD32 mAbs, FLI8.26 and KB61, were used for comparison. Binding experiments were performed using receptor concentrations of 0, 3·13, 6·25, 12·5, 25, 50 and 100 nm. For 2B6 and 3H7, data shown are averages ± standard deviation of three or more independent determinations. All other evaluations were obtained from two independent experiments; shown are the average values and, between parentheses, individual data. ND = no detectable binding.