Figure 2 | Scientific Reports

Figure 2

From: Novel intranasal vaccine targeting SARS-CoV-2 receptor binding ___domain to mucosal microfold cells and adjuvanted with TLR3 agonist Riboxxim™ elicits strong antibody and T-cell responses in mice

Figure 2

Monovalent SARS-CoV-2 RBD vaccines induce IgA antibody responses in NALF, BALF and serum. Mice were prime-boost immunized intranasally (d0, d21) with non-targeted (nt) RBD, strain Wuhan-Hu-1 (group #1), or M-cell targeted RBD (RBD-cCPE, group #7). Both vaccines were adjuvanted with Riboxxim. Sera were obtained on day 28, 1 week after the boost, diluted in fourfold steps, and assayed for IgG antibodies in Luminex with recombinant nt RBD, or recombinant trimeric spike protein, both derived from SARS-CoV-2 strain Wuhan-Hu-1. Endpoint titers (EP) were defined as highest dilution of a sample exceeding the mean signal of the lowest 2 dilutions + 3SD. Log10 of endpoint titers were plotted with geometric mean ± geometric SD. Two-way comparisons using the Mann–Whitney U test.

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