Evaluating mAb Prophylaxis against SARS-CoV-2

Eleven to 12-month-old female BALB/c mice (BALB/c AnNHsd, Envigo, stock# 047) were used for mouse-adapted SARS-CoV-2 (SARS-CoV-2 MA) in vivo protection experiments as described previously^{37 (link)}. Ten-week-old HFH4-hACE2 transgenic mice were used for SARS-CoV-2 WT in vivo protection experiments^{37 (link),77 (link)}. For evaluating the prophylactic efficacy of single mAbs and mAb combinations, mice were injected intraperitoneally (ip) with the appropriate concentration of each mAb combination 12 hours prior to infection. Mice were infected intranasally with 1 × 10⁵ PFU SARS-CoV-2 MA or SARS-CoV-2 WT, respectively. At 48 hours post-infection, mice were euthanized, and lung tissue was harvested for viral titer as measured by plaque assays. For viral plaque assays, the caudal lobe of the right lung was homogenized in PBS, and the tissue homogenate was then serial-diluted onto confluent monolayers of Vero E6 cells, followed by agarose overlay. Plaques were visualized with overlay of Neutral Red dye on day 2 post-infection. All mouse studies were performed at the University of North Carolina (Animal Welfare Assurance #A3410-01) using protocols (19-168) approved by the UNC Institutional Animal Care and Use Committee (IACUC) and were performed in a BSL3 facility at UNC.