Table 1. Combination indices for cell–cell and cell-free HIV-1 spread.
| Mode of infection | Combination index (CI)*† | Effect | ||||
|---|---|---|---|---|---|---|
| 50 | 75 | 90 | 95 | |||
| Combination AZT+TFV (ratio=1 : 1) | ||||||
| Cell–cell | AZT+TFV | 0.9 (0.1) | 0.85 (0.1) | 0.82 (0.05) | 0.74 (0.12) | Additive/synergistic |
| Cell-free | AZT+TFV | 0.41 (0.06) | 0.39 (0.03) | 0.42 (0.1) | 0.45 (0.04) | Synergistic |
| Combination AZT+NVP (ratio=40 : 1) | ||||||
| Cell–cell | AZT+NVP | 0.95 (0.05) | 1.05 (0.05) | 1.1 (0.13) | 1.1 (0.1) | Additive |
| Cell-free | AZT+NVP | 0.97 (0.06) | 0.89 (0.04) | 0.79 (0.06) | 0.76 (0.1) | Additive/synergistic |
| Combination TFV+EFV (ratio=1000 : 1) | ||||||
| Cell–cell | TFV+EFV | 0.59 (0.05) | 0.46 (0.07) | 0.36 (0.05) | 0.35 (0.02) | Synergistic |
| Cell-free | TFV+EFV | 0.1 (0.02) | 0.13 (0.01) | 0.22 (0.05) | 0.39 (0.1) | Synergistic |
| Combination LPV+TFV (ratio=1 : 1000) | ||||||
| Cell–cell | LPV+TFV | 0.03 (0.06) | 0.1 (0.01) | 0.12 (0.04) | 0.36 (0.2) | Synergistic |
| Cell-free | LPV+TFV | 0.02 (0.01) | 0.06 (0.01) | 0.15 (0.02) | 0.4 (0.13) | Synergistic |
| Combination LPV+NVP (ratio=1 : 25) | ||||||
| Cell–cell | LPV+NVP | 1.1 (0.07) | 0.92 (0.2) | 0.74 (0.24) | 0.71 (0.26) | Additive/synergistic |
| Cell-free | LPV+NVP | 0.86 (0.03) | 0.72 (0.03) | 0.6 (0.04) | 0.46 (0.04) | Additive/synergistic |
*Data are mean and sem from two independent experiments.
†50, 75, 90 and 95 indicate the percentage inhibition of infection in the presence of the combination being tested.