TABLE 4.
Combined treatment of C34 and Fab 3674 in HXB2 Env-pseudotyped virus neutralization assaysa
| Fab and C34/Fab 3674 ratio | Dose reduction indexb for:
|
CIc | |
|---|---|---|---|
| C34 | Fab-3674 | ||
| bF-3674 | |||
| 1:5 | 4.4 ± 0.6 | 2.7 ± 0.4 | 0.7 ± 0.2 |
| 1:7 | 6.7 ± 1.0 | 2.8 ± 0.5 | 0.6 ± 0.1 |
| 1:10 | 10.2 ± 1.6 | 2.8 ± 0.5 | 0.5 ± 0.1 |
| 1:15 | 9.5 ± 1.4 | 2.0 ± 0.3 | 0.7 ± 0.2 |
| 1:20 | 18.4 ± 3.1 | 2.9 ± 0.6 | 0.4 ± 0.1 |
| 1:25 | 16.2 ± 2.6 | 2.0 ± 0.3 | 0.6 ± 0.2 |
| mF-3674 | |||
| 1:20 | 2.0 ± 0.4 | 2.1 ± 0.5 | 1.2 ± 0.4 |
| 1:30 | 3.0 ± 0.6 | 2.1 ± 0.6 | 1.0 ± 0.4 |
| 1:40 | 4.3 ± 1.1 | 2.3 ± 0.7 | 0.8 ± 0.3 |
| 1:50 | 5.1 ± 1.0 | 2.1 ± 0.5 | 0.8 ± 0.3 |
a
The experiments were carried out as described previously (17).
b
The DRI is the ratio of IC50s in the absence and presence of the second inhibitor.
c
The CI is the summation of the effects of the two inhibitors in combination (see Materials and Methods). The synergistic, additive, and antagonistic effects of the combination of two inhibitors are defined by CI values of <1, 1, and >1, respectively (9). The IC50 values for C34, bF3674, and mF3674 alone are 28 ± 3, 78 ± 11, and 582 ± 112 nM, respectively.