Figure 2.

Prophylactic and therapeutic efficacy of FC05, FC08 or the cocktail of antibodies of FC05 and FC08 in SARS-CoV-2 susceptible mouse model. (A) Experimental design for therapeutic and prophylactic evaluations of FC05, FC08 or the cocktail of antibodies consisting of FC05 and FC08 by using a mouse-adapted SARS-CoV-2 virus (MASCp6) in mouse model. Group of BALB/c mice were infected intranasally with 2 × 10⁴ plaque forming unit (PFU) of MASCp6. A dose of 20 mg/kg of antibody was administrated intraperitoneally 12 h before infection (the prophylactic group, P) or at 2 h after infection (the therapeutic group, T). Phosphate buffer saline (PBS) injection was used as a negative control group. Then, the lung and the trachea tissues of mice were collected at 3 and 5 dpi for virus load measurement and histopathological analysis. (B) and (C) Virus loads of lung and trachea tissues at 3 dpi in mouse model. The viral loads of the tissues were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) (****P < 0.0001). Data are represented as mean ± SD. Dashed lines represent the limit of detection. (D) Virus loads of the lung. RNA was extracted and viral load was determined by a plaque assay of lung tissue homogenates (*P < 0.05; **P < 0.01; ***P < 0.001). Data are represented as mean ± SD. Dashed lines represent the limit of detection. (E) Histopathological analysis of lung and trachea samples at 3 dpi. Scale bar: 100 μm.