Fig. 6: Protective effects on the mucosa and development of local immunity after vaccination.
a, ELISA detecting anti-spike IgA levels in nasal washes of prime-vaccinated hamsters at indicated timepoints post challenge (dpc). Results display OD450. b, Neutralizing capacity against B.1 of nasal wash fluids from prime-boost-vaccinated hamster at indicated timepoints. Bar plots show mean ± s.d. Kruskal-Wallis and Dunn’s multiple comparisons test per timepoint; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Symbols indicate individual hamsters, n = 5 animals per group. c, Immunohistochemical staining of IgA in the olfactory epithelium and submucosal glands at 2 dpc. Scale bar, 60 µm. d, Longitudinal histopathological sections of olfactory epithelium, with H&E staining (left) and SARS-CoV-2 N protein immunohistochemistry (right) of the prime-only experiment at 2 dpc, with an additional section of an uninfected tissue. e, As in d but for the prime-boost vaccination experiment. Scale bar, 20 µm. In c–e, images are representative of n = 5 hamsters per indicated group. Prime and prime-boost experiments were performed independently. f, Virus RNA loads detected in nasal washes of prime-vaccinated hamsters at 2 and 5 dpc. In scatter dot plots, lines indicate means, symbols represent individual hamsters. n = 5. Two-way ANOVA and Tukey’s multiple comparisons test; *P < 0.05. g, Dot plots showing fold changes of gene expression in indicated cell types of the three prime vaccination strategies compared to mock-vaccinated animals. Selected interferon-stimulated genes and pro-inflammatory cytokines are visualized as follows: coloration and point size indicate log2-transformed FC and P values, respectively, in vaccinated compared to mock-vaccinated animals. Padj were calculated by DEseq2 using Benjamini–Hochberg corrections of two-sided Wald test P values. Genes are ordered by unsupervised clustering.
