Table 2.
Comparison of apparent affinities of membrane-bound gp145 obtained from flow cytometry titration vs. soluble gp140 Env variants obtained from ELISA titration.
| V3 peptides | Membrane-bound gp145 | Soluble gp140 | ||||
|---|---|---|---|---|---|---|
| KD [nM] |
KD [nM] (flow cytometry titration, n = 3) |
KD [nM] (ELISA titration, n = 3) |
||||
| V3 loop substitution | 447–52D | HGN194 | 447–52D | HGN194 | 447–52D | HGN194 |
| MN | 0.6- | NA | 0.9 ± 0.08 (R2 = 0.990) | 0.6 ± 0.04 (R2 = 0.981) | 0.4 ± 0.02 (R2 = 995) | 0.2 ± 0.05 (R2 = 0.926) |
| HXB2 | 24 | 2 ± 0.2 (R2 = 0.991) | 1.3 ± 0.2 (R2 = 0.973) | 0.5 ± 0.002 (R2 = 0.983) | 7 ± 5 (R2 = 0.537) | |
| CDC42 | 5 | 3 ± 0.2 (R2 = 0.996) | 1.5 ± 0.09 (R2 = 0.951) | 1 ± 0.4 (R2 = 0.983) | 0.6 ± 0.2 (R2 = 0.797) | |
| RF | 0.9 | 7 ± 1 (R2 = 0.972) | NA | 74 ± 7 (R2 = 0.992) | NA | |
| SF33 | NA | NA | NA | NA | NA | |
KD values were calculated using nonlinear least squares regression for titration of membrane-bound gp145 Envs and soluble gp140 Envs. Due to low antibody binding, the apparent KD values for RF and SF33 could not be calculated in some cases (NA). Values for V3 peptides were adopted from ref.30