J08-MUT

The original antibody was shown to potently bind SARS-CoV-2 Spike protein trimer in prefusion conformation (EC50 of 5.8 ng/mL). The antibody was shown to bind the loop containing residues 477 to 489 of Spike protein. J08-MUT inhibited the interaction between Spike protein and its receptor on Vero E6 cells (IC50 of 78.6 ng/mL). It displayed potent neutralizing capacity against wild type SARS-CoV-2 (IC100 of 3.9 ng/mL) and its variants D614G (IC100 of 7.8 ng/mL) or B.1.1.7. The authors cite (a pre-print) also E484K neutralization. (It did not display SARS-CoV and MERS-CoV pseudotyped virus cross-neutralization.) Intraperitoneal administration of J08-MUT dose-dependently protected hamsters from weight loss (prophylactic dosing) or let the animals regain the lost body weight significantly faster (therapeutic dosing) compared to control. The treatment led to viral RNA elimination in lung tissue at day 3 post infection (at 1 mg/kg in prophylactic and at 4 mg/kg at therapeutic dosing).