Fig. 3
From: A triple-RBD-based mucosal vaccine provides broad protection against SARS-CoV-2 variants of concern
Antibody responses by the intranasal immunization of 3Ro-NC adjuvanted with KFD in BALB/c mice. A Diagrammatic scheme of the immunization and sampling (n = 5 mice per group). B RBD-specific IgG responses in serum. C–G Neutralization antibody responses in serum tested in a pseudotyped virus system. C Neutralization antibody titers against the pseudotyped SARS-CoV-2 variants or SARS-CoV-1 in serum after the 2nd and 3rd immunizations. Each connecting line indicates the neutralizing titers of one individual serum sample against different virus strains. D Geometric mean titers of the neutralizing antibodies in serum against different variants. E The ratio of neutralizing antibody titers against Omicron BA.1 to those against Delta or the original strain. F, G Antigenic maps were generated from the second (square) or the third vaccination (triangle) serum samples of the 3Ro-NC + KFDi.n. group (brown) and 3Ro-NC + ALi.m. group (gray). Cyan, green, yellow, blue, red, purple, and black circles correspond to the Alpha, Beta, Gamma, Delta, Omicron BA.1, original strain and SARS-CoV-1, respectively. Each grid square corresponds to a twofold dilution in the neutralization assay. The antigenic distance is interpretable in any direction. H–J RBD-specific mucosal IgA responses in saliva (H), vaginal lavage fluid (I) and nasal turbinate lavage fluid (J). Data are presented as the mean ± SEM and are representative of at least two independent experiments.; GMT of NT50 are indicated. Groups were compared using one-way ANOVA. *P < 0.05; **P < 0.01; ***P < 0.001; ns, nonsignificant
