Fig. 3.

Prophylactic effects of neutralizing RBD-chAbs against SARS-CoV-2 infection. One day prior to intranasal (i.n.) challenge of WT SARS-CoV-2, each group of hamsters was given a single intraperitoneal injection of 3 mg/kg RBD-chAb-15 (n = 3), 3 mg/kg RBD-chAb-45 (n = 3), total of 3 mg/kg RBD-chAb-15 combined with RBD-chAb-45 (n = 3), or 3 mg/kg NHIgG isotype control (n = 3). On day 3 after virus inoculation, lung samples were collected for analysis. A The viral load in the lungs of treated hamsters was determined by qRT-PCR. B The viral load in the lungs of treated hamsters was determined by median tissue culture infectious dose per ml (TCID₅₀/ml). Statistical differences were determined by two-tailed Student t test. ***P < 0.001