Table 5.
KD values for the binding of yeast cell surface displayed WT core gp120 and its PNGS mutants with various CD4-binding site antibodies as determined by FACS titrations
KD is equilibrium dissociation constant determined using FACS; S.D. is standard deviation for the data from two independent experiments; b12/VRC01 is broadly neutralizing antibodies against HIV-1; b6, non-neutralizing anti HIV-1 antibody.
| Construct | Mutations |
KD ± S.D. (nm)a |
|
|---|---|---|---|
| VRC01 | b6 | ||
| WT core gp120 | 24.3 ± 0.4 | 1.75 ± 0.2 | |
| ΔG15 core gp120 | all 15 PNGS mutated | >500 | –b |
| ΔG4 core gp120 | N276D + N386D + N392S + N463D | 2.33 ± 0.3 | 0.1 ± 0.006 |
| E168K ΔG4 full-length gp120c | E168K + N276D + N386D + N392S + N463D | 20.5 ± 5.3 | 2.8 ± 0.7 |
| ΔG11 core gp120 | 11 PNGS mutated (*). PNGS at positions 88, 241, 262, and 276 retained. | 17 ± 0.25 | 0.4 ± 0.03 |
| ΔG12a core gp120 | (*) + N88Q | 43.5 ± 5 | 1.87 ± 0.7 |
| ΔG12b core gp120 | (*) + N241K | 94.2 ± 19.2 | 1.82 ± 0.7 |
| ΔG12c core gp120 | (*) +N262D | 26 ± 5.3 | 0.3 ± 0.04 |
| ΔG12d core gp120 | (*) + N276D | 2.8 ± 0.9 | 0.3 ± 0.07 |
| ΔG13 core gp120 | (*) + N262D + N276D | 4.9 ± 0.7 | 0.5 ± 0.1 |
| ΔG14a core gp120 | (*) + N262D + N276D + N88G | 4.2 ± 0.25 | 0.35 ± 0.006 |
| ΔG14b core gp120 | (*) + N262D + N276D + N241H | 4.9 ± 1.8 | 0.45 ± 0.01 |
a KD values for the binding of WT core gp120, ΔG4 core gp120, E168K ΔG4 full-length gp120, and ΔG11 core gp120 with CD4D12 (two-domain CD4) were found to be 27 ± 1.9, 22 ± 0.4, 18.2 ± 2, and 32 ± 2.3 nm, respectively; whereas KD values for binding with bNAb b12 were found to be 1.2 ± 0.6, 0.4 ± 0.06, 11.2 ± 6.9, and 0.6 ± 0.3 nm, respectively, as determined by FACS.
b – indicates no detectable binding.
c This contains V1/V2 and V3 variable loops, all other gp120 constructs lack these.