Fig. 3: The RBD-homodimer vaccine protected hACE2-transgenic C57BL/6 mice from the infection of SARS-CoV-2. | Cell Discovery

Fig. 3: The RBD-homodimer vaccine protected hACE2-transgenic C57BL/6 mice from the infection of SARS-CoV-2.

From: RBD-homodimer, a COVID-19 subunit vaccine candidate, elicits immunogenicity and protection in rodents and nonhuman primates

Fig. 3: The RBD-homodimer vaccine protected hACE2-transgenic C57BL/6 mice from the infection of SARS-CoV-2.The alternative text for this image may have been generated using AI.

a The experiment scheme. Male C57BL/6 mice were vaccinated at Day 0 and Day 14, or Day 0, Day 14, and Day 28. Mice of the 5 µg RBD-AL adjuvant, 10 µg RBD-AL or AL only group were infected with 1.0 × 105 PFU/mouse SARS-CoV-2 at Day 40. At 5 d.p.i., all the mice from each group were euthanized for lung anatomy. b Bars indicated the GMT of anti-SARS-CoV-2 RBD-specific IgG titers. Sera collected after each vaccination were detected by ELISA. The x axis showed the RBD dose and vaccinated times. c Sera collected from 5 and 10 µg RBD group after twice or three-time vaccination were examined by PRNT, and the GMTs calculated from PRNT50 were presented. d Total viral genome copies in lung from each mouse post challenge were detected by RT-qPCR with a pair of primers targeting S gene under standard curve method. The limit of qPCR detection was 235 copies per reaction. The data were presented as means ± SEM. e Lung tissues from mice dissected at 5 d.p.i. were executed pulmonary pathological detection by H&E staining (upper). Representative pictures from each group were displayed. Scale bar, 100 µm (20×). Arrow points the area appearing alveolar wall thickening, inflammatory cell infiltration, local bleeding, or other. Immunofluorescence analysis of viral antigens in lungs after challenge (lower). Sections were stained with antibodies targeting SARS-CoV-2 NP. DAPI was used to stain the nucleus. Scalar bars, 50 µm (40×). **P < 0.01.

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