Fig. 8. Immunogenicity and efficacy of LNP-based DNA vaccine against SARS-CoV-2 variants Gamma lineage (P.1) in hamsters.

A Scheme of immunization: Syrian hamsters were immunized with controls and LNP-HPS and boosted with equivalent doses 3 weeks later. Immunized hamsters were challenged with 6 × 10⁵ PFU of SARS-CoV-2 variants Gamma lineage (P.1) 15 days after boost. Lungs were harvested 5 days post infection for all immunized groups. B The weight loss was monitored for 5 days after challenge (n = 5/group). C SARS-CoV-2 genome copies detected in the lung of the immunized hamsters at 5 days post infection (Mock, pHPS, and BNT-mRNA n = 4; PBS, LNP-C, and LNP-HPS n = 5). D, E The plaque-forming unit measures the viable Vero cells treated with serum of immunized hamsters 5 days post infection (n = 5/group). Dashed line indicates limit of detection. F Histopathological analysis at ×20 magnification of the lungs at 5 days post infection with the P.1 strain (n = 5/group). Histopathological score for G pleura, H bronchi, I alveoli, and J vessels (n = 5/group). The arrows indicate pleura (pink), bronchi (blue), alveoli (red), edema (yellow), vessels (green) and vessels congestion (orange). Data are presented as mean ± SEM; ns not significant, *p < 0.05, **p < 0.01, ***p < 0.001. B Two-tailed, unpaired Spearman correlation to test. C Kruskal–Wallis followed by Dunn’s multiple comparisons test. D One-way ANOVA with Dunnet’s post hoc test. G–J Two-way ANOVA followed by Tukey’s multiple comparison test. Source data are provided as a Source Data file.