Table 4.
SPR binding parameters for conformation-dependent antibodies
| Antibody | Parametera (units) | SPR-derived binding values for gp120-ligand interactionb |
|||
|---|---|---|---|---|---|
| 1157ip | 1084i | HXB2 | SF162 | ||
| sCD4 | ka (M−1 s−1) | 2.67 (1) × 103 | 8.5 (2) × 103 | 37 (5) × 103 | 13.1 (4) × 103 |
| kd (s−1) | 7.41 (3) × 10−4 | 4.9 (1) × 10−4 | 3.3 (2) × 10−4 | 2.46 (6) × 10−4 | |
| KD (nM) | 277 (1) | 58 (2) | 9 (2) | 18.8 (2) | |
| CD4-IgG2 | ka (M−1 s−1) | 3.91 (8) × 103 | 10.5 (1) × 103 | NDc | 25 (4) × 103 |
| kd (s−1) | 5 (2) × 10−5 | 7.1 (6) × 10−5 | ND | 0.9 (5) × 10−5 | |
| KD (nM) | 13 (4) | 6.8 (6) | ND | 0.4 (3) | |
| IgG1-b12 | ka (M−1 s−1) | 2.6 (1) × 103 | —d | 430 (40) × 103 | 150 (10) × 103 |
| kd (s−1) | 9.4 (5) × 10−4 | — | 5.4 (1) × 10−4 | 9.2 (2) × 10−4 | |
| KD (nM) | 362 (1) | — | 1.3 (1) | 6.2 (6) | |
| M90 | ka (M−1 s−1) | 1.18 (4) × 104 | 1.7 (3) × 104 | 4.9 (4) × 104 | 3.89 (7) × 104 |
| kd (s−1) | 5.41 (7) × 10−4 | 2.4 (1) × 10−4 | 0.9 (2) × 10−4 | 1.88 (5) × 10−4 | |
| KD (nM) | 45.7 (8) | 14 (3) | 1.9 (6) | 4.8 (2) | |
a
ka, rate of association; kd, rate of dissociation; KD, equilibrium dissociation constant.
b
Values are means ± standard deviations. Values in parentheses are errors for the last significant figure; see Table 3.
c
ND, experiment not done.
d
—, data fit poorly to a 1:1 binding model.