TABLE 2.
N1-3-VHH and N1-5-VHH in a mono- or bivalent format inhibit N1rec activity and reduce the plaque size of H5N1 virus-infected cells
| N1-VHH format | N1rec inhibition (IC50, nM)a | Foldc | NIBRG-14 (IC50, nM)b | Foldc | H5N1 H274Yb | Foldc | NIBRG-23b | Foldc |
|---|---|---|---|---|---|---|---|---|
| N1-3-VHHm | 425.2 ± 149.4 | 1,844 ± 344.3 | 6,440 ± 1,247 | 4,295 ± 2,835.4 | ||||
| N1-5-VHHm | 374.9 ± 118.5 | 848.5 ± 380.2 | >26,500 | 3,492 ± 2,967.6 | ||||
| N1-7-VHHm | >15,448 | >32,896 | >32,896 | >32,896 | ||||
| SA-VHHmd | >15,448 | >32,896 | >32,896 | >32,896 | ||||
| N1-3-VHHb | 0.157 ± 0.206 | 2,708 | 7.6 ± 3.0 | 240 | 52.2 ± 36.8 | 123 | 24.6 ± 31.9 | 174 |
| N1-5-VHHb | 0.69 ± 0.231 | 543 | 14.5 ± 11.1 | 58 | >707.5 | 23.6 ± 3.8 | 148 | |
| BL-VHHbe | >15,448 | >32,896 | >32,896 | >32,896 | ||||
| N1-3-VHH-Fc | 1.31 ± 0.605 | 324 | 23.08 | 79 | 89.4 ± 7.8 | 71 | 24.2 ± 3.7 | 177 |
| N1-5-VHH-Fc | 1.49 ± 0.746 | 251 | 28.14 | 30 | >17,083 | 27.03 | 129 | |
| N1-7-VHH-Fc | >7,900 | >5,260 | >5,260 | >5,260 | ||||
| GP4-Fcf | >7,900 | >5,260 | >5,260 | >5,260 | ||||
| Oseltamivir | 586.1 ± 120.5 | 15,030 ± 10,039 | >243,000 | 73,000 |
a
Mean IC50 from three independent NA inhibition assays with 4-MUNANA and 160 ng of N1rec.
b
Mean plaque IC50 from two independent plaque assays performed in duplicate in which the VHH concentration reduced the plaque size by 50% compared with mock VHH.
c
Fold increase in the inhibitory potency of the N1-VHH bivalent format compared with its monovalent format.
d
Monomeric VHH against seed storage albumin.
e
Bivalent VHH against bacterial β-lactamase.
f
Coronavirus GP4 protein fused to mouse IgG2a Fc.