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. 2022 May 13;13:2674. doi: 10.1038/s41467-022-30222-w

Fig. 5. Protective efficacy of HexaPro-bearing immunogens in mice following challenge with SARS-CoV-2 B.1.351 variant in vivo.

Fig. 5

a–c six-week-old male BALB/c mice were subcutaneously immunized with an equivalent amount of HexaPro-based immunogen (equal to 5 µg HexaPro) at weeks 0 and 3. At 4 weeks after the second vaccination, the mice were intranasally inoculated with 2 × 106 PFU/ml SARS-CoV-2 B.1.351 variant authentic virus. Lung tissues were collected for virus titer qualification and clinicopathological analysis. a Body weight changes of mice (n = 4 mice in HexaPro-based-vaccinated group, n = 2 in PBS-treated group) after infection with SARS-CoV-2 B.1.351 variant. The body weight of each mouse was recorded daily for 8 days. b Virus titers of lung tissues from SARS-CoV-2 B.1.351 variant-challenged mice (n = 4 mice in HexaPro-based-vaccinated group, n = 3 in PBS-treated group) at 2 days post challenge. LOD limit of detection. Statistical significance was determined by two-tailed unpaired t test. WT HexaPro, WT NP, Cocktail NP, and Mosaic NP vs PBS, ***p = 0.0001. c Immunohistological analysis of lung tissues from SARS-CoV-2 B.1.351 variant-challenged mice (n = 2 mice in each experimental group) at 4 days post challenge. Hematoxylin and eosin staining (HE, left) and immunohistochemistry (IHC, right) microscopic images are shown in the figure at magnification. Scale bar for H&E, 250 μm (left); 50 μm (middle); 25 μm (right), Scale bar for IHC, 50 μm. In a and b, the data were expressed and plotted as means ± SD. Source data are provided as a Source Data file.