Table 2.
Neutralization potencies of VHHs against SARS-CoV-2 Wuhan and variants.
| VHH | Epitope bin | SVNA IC50 (nM)c | PVNA IC50 (nM)c | LVNA IC50 (nM)c | |||||
|---|---|---|---|---|---|---|---|---|---|
| VHH | VHH-Fc | VHH | VHH-Fc | VHH-Fc | |||||
| Wuhan | Alpha | Beta | Omicron | ||||||
| RBD-specific VHH | |||||||||
| 1d | 1 | 8.6 | 5.4 | 50 | 16.7 | 1.94 | 0.37 | 2.14 | nde |
| 02 | 2/3 | 5.1 | 5 | 43 | 6.5 | 0.12 | 0.09 | – | nde |
| 03 | 6 | – | – | 910 | 26.6 | 58 | 16 | 62 | ~150 |
| 04 | 4 | – | 11.7 | 111 | 26.6 | 1.65 | 2.3 | – | 6.03 |
| 05 | 2/3 | 9.5 | 6.7 | 79 | 2.3 | 0.0008 | 0.03 | – | nde |
| 06 | 5 | – | – | 2500 | 24.2 | 76 | – | – | 13.95 |
| 07 | 1 | 7.5 | 6.8 | 44 | 15.6 | 6.15 | 0.42 | 3.18 | nde |
| 10 | 2/3/4 | 16.1 | 7.7 | 48 | 2.9 | 1.28 | 0.47 | 2.25 | 0.19 |
| 11 | 6 | – | 9.7 | 61 | 30.8 | 9.9 | 2.3 | 18.5 | 2.32 |
| 12a | 1 | ndd | 7.3 | ndd | 6.7 | 2.82 | 1.35 | 2.62 | 4.72 |
| 14 | 2/4 | 21.3 | 9.9 | 84 | 6.6 | 3.1 | 0.88 | 32.8 | 0.46 |
| 15 | 2/3/4 | 12.1 | 8.1 | 39 | 5.7 | 0.73 | 0.16 | 0.43 | 0.25 |
| 17 | 3/4 | – | 8.6 | 44 | 6.3 | 2.82 | 0.61 | 34.7 | 2.41 |
| 18 | 1 | 8.9 | 12 | 41 | 28.7 | 6.4 | 2.82 | 9.48 | nde |
| 20 | 1 | 5.1 | 8.7 | 196 | 7.6 | 11.2 | 1.94 | 2.88 | 5.58 |
| MRed04 | 1 | 6.1 | 8.3 | 62 | 3.8 | 9.61 | 4.5 | 5.73 | ~100 |
| MRed05a | 2/3/4 | 15.3 | 6.1 | ndd | 10 | 0.17 | 0.13 | 0.11 | nde |
| VHH-72b | 1 | 59 | 7.2 | 490 | 25 | 8.46 | 1.86 | 9.34 | nde |
| NTD-specific VHH | |||||||||
| SR01 | 7/9/10 | – | 6.6 | 188 | 19.5 | 9.42 | 3.77 | 70.3 | 6.64 |
| SR02 | 10 | – | 5.8 | ndd | 11.3 | 14.13 | 9.05 | ~300 | 9.04 |
| SR03 | 7/9/10 | – | – | 269 | 29.4 | ~500 | 22.2 | – | ~150 |
| SR04 | 7/9 | – | – | – | – | ~500 | – | – | – |
| SR13 | 7/9/10 | – | 23.8 | 41 | 86.9 | ~100 | ~100 | – | – |
| SR16 | 7/9/10 | – | – | – | 17.5 | 54.2 | 17.8 | 100 | – |
| MRed03 | 8 | – | – | – | – | – | – | – | – |
| MRed06 | 8 | – | – | – | – | – | – | – | – |
| MRed07 | 9 | – | – | – | – | – | – | – | – |
| S2-specific VHH | |||||||||
| S2A3 | 11 | – | – | ndd | – | 12.2 | 31 | 54 | 5.36 |
| S2A4 | 12 | – | – | – | – | – | – | – | – |
| S2F3 | 13 | – | – | ndd | – | – | – | – | – |
| S2G3 | 14 | – | – | – | – | ~200 | – | – | – |
| S2G4 | 15 | – | – | – | – | ~200 | – | – | – |
| MRed11 | 16 | – | – | – | – | – | – | – | – |
| MRed18 | 13 | – | – | – | – | – | ~400 | – | – |
| MRed19 | 13 | – | – | – | – | – | – | – | – |
| MRed20 | 13 | – | – | – | – | – | – | – | – |
| MRed22 | 13 | – | – | – | – | – | – | – | nde |
| MRed25 | 17 | – | – | – | – | – | – | – | – |
aThe neutralization potencies of nanobodies 12 and MRed05 were not assessed in their VHH format due to insufficient expression.
bVHH-72 benchmark is SARS-CoV S-specific VHH that cross-reacts with SARS-CoV-2 S30.
cSVNA, PVNA, LVNA, surrogate, pseudo-typed, and live virus neutralization assay, respectively.
dnd, not determined (lack of sufficient quantities of VHHs precluded their assessment for neutralization capabilities).
end, not determined since they were negative for binding to Omicron S and as a results were not assayed for Omicron neutralization capabilities. Dash indicates lack of neutralization.