TABLE 3.
Synergy of human IgG MAbs F105, 694/98D, 2F5, and 2G12 for SHIV-vpu+ neutralizationa in MT-2 cells
| Single MAb (specificity) or combination (ratio) | Concn (μg/ml) for neutralization at:
|
CI90b | DRI at EC90c
|
||||
|---|---|---|---|---|---|---|---|
| 50% | 90% | MAb A | MAb B | MAb C | MAb D | ||
| F105 (anti-CD4bd) | 1.3 | NAd | |||||
| 694/98D (anti-V3) | 1.8 | NA | |||||
| 2F5 (anti-gp41) | 0.6 | 5.1 | |||||
| 2G12 (anti-gp120) | 0.5 | 4.9 | |||||
| F105 + 694/98D (1:1) | 1.4 | 8.9 | 0.4 | 5.2 | 5.5 | ||
| F105 + 2F5 (2:1) | 0.8 | 5.3 | 0.5 | 6.5 | 2.9 | ||
| F105 + 2G12 (2:1) | 0.8 | 4.7 | 0.5 | 7.4 | 3.1 | ||
| 694/98D + 2F5 (2:1) | 0.7 | 3.7 | 0.4 | 9.9 | 4.1 | ||
| 694/98D + 2G12 (2:1) | 0.8 | 4.0 | 0.4 | 9.1 | 3.7 | ||
| 2F5 + 2G12 (1:1) | 0.4 | 1.8 | 0.4 | 5.6 | 5.5 | ||
| F105 + 694/98D + 2F5 (2:2:1) | 0.8 | 3.6 | 0.3 | 15.4 | 16.3 | 6.7 | |
| F105 + 694/98D + 2G12 (2:2:1) | 0.9 | 3.5 | 0.3 | 16.7 | 17.6 | 7.1 | |
| F105 + 2F5 + 2G12 (2:1:1) | 0.6 | 2.8 | 0.4 | 16.1 | 7.0 | 6.8 | |
| 694/98D + 2F5 + 2G12 (2:1:1) | 0.5 | 2.7 | 0.3 | 17.2 | 7.1 | 6.9 | |
| F105 + 694/98D + 2F5 + 2G12 (2:2:1:1) | 0.5 | 1.8 | 0.2 | 37.9 | 39.9 | 16.5 | 16 |
a
The dose for neutralization by combination of two, three, or four antibodies was that for the sum of each antibody used in the combination regimen.
b
Synergy is indicated when the CI is <1.0. CIs were calculated based on the classical isobol equation (8, 10).
c
DRIs were measured by comparing the doses required to reach a given degree of virus neutralization (i.e., 90%) when the antibody was used alone and in combination with other antibodies. Antibodies A, B, C, and D indicate the antibodies in first, second, third, and fourth positions, respectively.
d
NA, not achieved at the highest concentration tested.