Figure 6.

The efficacy of Nb₁₅s evaluated in hACE2 transgenic mice challenged by SARS-CoV-2

(A) Experimental schedule of Nb₁₅s in the prevention and treatment of SARS-CoV-2 infection. Bottom, table summary of groups (n = 3–5 mice) with different treatments.

(B) Viral loads in lungs among 7 groups were measured by qRT-PCR. The name of each group in the x axis was indicated as in the table in (A). Each dot represents one mouse. The limit of detection was 3,160 copies/mg referenced to blank control (no-SARS-CoV-2 group).

(C) Sections of lungs were analyzed by immunofluorescence staining by using antibodies specific to SARS-CoV-2 nucleocapsid protein (NP) in red and DAPI (4′,6-diamidino-2-phenylindole) for nuclei in blue, respectively. The fluorescence signal intensity of red was taken as a quantitative indicator for viral infection, which was calculated by ImageJ software.

(D) Representative sections of lung in (C) were visualized under the ×20 objective at the indicated scale bar (200 μm). The insets are enlarged images of individual cells indicated by corresponding arrows at the indicated scale bar as 10 μm. H&E staining was conducted to analyze the lung inflammation and observed at the indicated scale bar as 100 μm.

(E) Body weights of mice among the above 7 groups were recorded. Each line represents data from one group.

(F) Snapshot of body weight on 3 days post infection in (E) was plotted. Data are represented as mean ± SEM; Mann-Whitney test was performed to compare treatment group with the SARS-CoV-2 control group. ns, no significance; ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001. Data of (B), (C), (E), and (F) are represented as mean ± SEM. All experiments of (B) and (C) were repeated twice.