Table 3.
CI values for HNG-156 in combination with other inhibitors
| Combinationa | EC50 |
EC90 |
||
|---|---|---|---|---|
| CI value | Conclusionb | CI value | Conclusion | |
| HNG-156 + sCD4 | 1.03 ± 0.24 | Additivity | 0.95 ± 0.17 | Additivity |
| HNG-156 + MVC | 0.83 ± 0.22 | Moderate synergy | 0.56 ± 0.13 | Synergy |
| HNG-156 + TAK | 0.87 ± 0.17 | Slight synergy | 0.56 ± 0.05 | Synergy |
| HNG-156 + C34 | 1.10 ± 0.36 | Additivity | 0.84 ± 0.03 | Moderate synergy |
| HNG-156 + CVN | 0.60 ± 0.10 | Synergy | 0.77 ± 0.14 | Moderate synergy |
| HNG-156 + GRFT | 0.57 ± 0.24 | Synergy | 0.45 ± 0.06 | Synergy |
| HNG-156 + 2G12 | 0.64 ± 0.08 | Synergy | 0.61 ± 0.12 | Synergy |
| HNG-156 + TDF | 1.00 ± 0.40 | Additivity | 0.62 ± 0.10 | Synergy |
MVC, maraviroc; TAK, TAK-779; CVN, cyanovirin-N; GRFT, griffithsin; TDF, tenofovir.
The drug interactions of the combinations were analyzed by the combination index (CI) analysis developed by Chou and Talalay (8, 9) using CalcuSyn software. A CI value of 0.3 to 0.7 indicates synergism; 0.7 to 0.85, moderate synergism; 0.85 to 0.9, slight synergism; 0.9 to 1.1, additivity; and >1.1, antagonism (8, 9). The compounds were combined at fixed ratios based on their EC50s and were mixed with HIV-1BaL for 30 min prior to addition to HOS.T4.R5 cells. All assays were repeated in a minimum of three independent trials in triplicate wells. Experimental deviation was calculated as the standard error of the mean.