TABLE 2.
Characterization of CD4, CD4i, and CD4-binding site antibody binding to HIV-1YU2 gp120 W69 variants by surface plasmon resonancea
| gp120 variant | CD4-Ig |
17b |
17b plus sCD4 |
A32 |
N60-i3 |
VRC16 |
b12 |
||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| On rate (M−1 s−1) | Off rate (s−1) | KD (M) (fold change) | On rate (M−1 s−1) | Off rate (s−1) | KD (M) (fold change) | On rate (M−1 s−1) | Off rate s−1) | KD (M) (fold change) | On rate (M−1 s−1) | Off rate (s−1) | KD (M) (fold change) | On rate (M−1 s−1) | Off rate (s−1) | KD (M) (fold change) | On rate (M−1 s−1) | Off rate (s−1) | KD (M) (fold change) | On rate (M−1 s−1) | Off rate (s−1) | KD (M) (fold change) | |
| WT | 9.71 × 103 | 2.23 × 10−4 | 2.29 × 10−8 (1.0) | 1.78 × 104 | 3.41 × 10−5 | 1.92 × 10−9 (1.0) | 3.14 × 104 | 2.15 × 10−5 | 1.92 × 10−10 (1.0) | 3.14 × 104 | 3.01 × 10−5 | 9.57 × 10−10 (1.0) | 2.68 × 104 | 5.88 × 10−5 | 2.19 × 10−9 (1.0) | 5.52 × 103 | 9.16 × 10−3 | 1.66 × 10−6 (1.00) | 2.74 × 104 | 4.82 × 10−3 | 1.76 × 10−7 (1.00) |
| W69G | 9.65 × 103 | 9.31 × 10−4 | 9.65 × 10−8 (4.2) | 2.61 × 102 | 2.40 × 10−4 | 9.20 × 10−7 (479) | 9.44 × 103 | 6.76 × 10−5 | 9.20 × 10−9 (10.5) | ND | ND | ND | ND | ND | ND | 4.91 × 103 | 3.12 × 10−3 | 6.35 × 10−7 (0.38) | 2.61 × 104 | 2.91 × 10−3 | 1.11 × 10−7 (0.63) |
| W69A | 9.76 × 103 | 8.35 × 10−4 | 8.56 × 10−8 (3.7) | 3.01 × 102 | 2.07 × 10−4 | 6.90 × 10−7 (359) | 1.01 × 104 | 6.47 × 10−5 | 6.90 × 10−9 (9.3) | ND | ND | ND | ND | ND | ND | 5.55 × 103 | 4.05 × 10−3 | 7.30 × 10−7 (0.44) | 2.72 × 104 | 3.81 × 10−3 | 1.40 × 10−7 (0.80) |
| W69I | 9.31 × 103 | 7.24 × 10−4 | 7.77 × 10−8 (3.4) | 3.79 × 102 | 2.02 × 10−4 | 5.33 × 10−7 (277) | 1.18 × 104 | 7.00 × 10−5 | 5.33 × 10− (8.7) | ND | ND | ND | ND | ND | ND | 5.22 × 103 | 5.36 × 10−3 | 1.03 × 10−6 (0.62) | 2.59 × 104 | 4.85 × 10−3 | 1.87 × 10−7 (1.07) |
| W69L | 9.47 × 103 | 7.08 × 10−4 | 7.47 × 10−8 (3.3) | 3.09 × 102 | 1.89 × 10−4 | 6.11 × 10−7 (318) | 1.15 × 104 | 6.07 × 10−5 | 6.11 × 10−9 (7.7) | ND | ND | ND | ND | ND | ND | 6.05 × 103 | 4.15 × 10−3 | 6.86 × 10−7 (0.41) | 2.67 × 104 | 3.87 × 10−3 | 1.45 × 10−7 (0.83) |
| W69F | 9.77 × 103 | 3.00 × 10−4 | 3.07 × 10−8 (1.3) | 1.57 × 104 | 4.36 × 10−5 | 2.78 × 10−9 (1.5) | 1.81 × 104 | 3.35 × 10−5 | 2.78 × 10−9 (2.7) | 2.04 × 104 | 7.78 × 10−5 | 3.82 × 10−9 (4.0) | 2.07 × 104 | 5.56 × 10−5 | 2.68 × 10−9 (1.2) | 5.14 × 103 | 8.34 × 10−3 | 1.62 × 10−6 (0.98) | 2.84 × 104 | 5.40 × 10−3 | 1.90 × 10−7 (1.08) |
| W69A/S115W | 9.64 × 103 | 3.59 × 10−4 | 3.73 × 10−8 (1.6) | 3.22 × 102 | 2.14 × 10−4 | 6.65 × 10−7 (346) | 1.85 × 104 | 6.19 × 10−5 | 6.65 × 10−9 (4.9) | ND | ND | ND | ND | ND | ND | 5.07 × 103 | 3.00 × 10−3 | 5.92 × 10−7 (0.36) | 2.81 × 104 | 4.03 × 10−3 | 1.44 × 10−7 (0.82) |
a
CD4-Ig,17b, A32, N60-i3, VRC16 or b12 was immobilized directly onto a CM5 sensor chip, and the binding of the indicated gp120 protein was evaluated as described in Materials and Methods. KD, equilibrium dissociation constant. ND, signal too low to be detected.