TABLE 3.
Antigenic and biophysical characterization of E2 designs
| sE2 constructa | Tm (°C)b | Antibody/receptor binding KD (nM)c
|
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Domain A |
Domain B |
Domain D |
Domain E |
Receptor | ||||||
| CBH-4D | CBH-4G | AR3A | HEPC74 | HC84.26.WH.5DL | HC84.1 | HCV1 | HC33.1 | CD81 | ||
| sE2 wild-type | 84.5 | 8.4 | 15 | 1.8 | 5.1 | 4.3 | 30 | 42 | 9.5 | 22 |
| H445P | 83.1 | 14 | 15 | 1.1 | 4.6 | 0.4 | 31 | 70 | 8.0 | 23 |
| Y632NS | 81.4 | 37 | 180 | 1.2 | 4.6 | 4.0 | 83 | 26 | 6.5 | 31 |
| ΔHVR1 | 84.5 | 5.8 | 20 | 1.5 | 7.0 | 3.1 | 60 | 42 | 7.9 | 15 |
| ΔHVR1-H445P | 82.9 | 11 | 15 | 1.5 | 2.3 | 2.4 | 51 | 46 | 7.6 | 10 |
| ΔHVR1-Y632NS | 80.0 | 7.7 | 140 | 1.8 | 9.0 | 2.2 | 110 | 50 | 6.7 | 140 |
| Triple | 76.5 | 22 | 110 | 1.4 | 4.6 | 2.8 | 58 | 27 | 9 | 40 |
sE2 wild-type corresponds to residues 384 to 661 of H77C E2, and listed designs represent point mutants or truncations of that sequence. Y632NS is an abbreviation for the double mutant Y632N to G634S, and ΔHVR1 denotes deletion of most of the HVR1 sequence at the N terminus of E2, with the resultant construct containing residues 408 to 661. Triple, combination of the ΔHVR1, H445P, and Y632NS designs.
Tm values were measured by differential scanning calorimetry.
Dissociation constant (KD) values were measured by Octet biolayer interferometry. Antibodies are classified by their mapping to antigenic domains A, B, D, and E on E2 (28). Values in bold denote KD changes of more than 5-fold versus the wild-type E2 level for that antibody.