FIGURE 3.

Intranasal immunization with CuMV_TT‐RBD promotes isotype switching to IgA and leads to balanced IgG subclass responses. (A) RBD‐specific IgG1, IgG2a, IgG2b, and IgG3 titer for the groups vaccinated with CuMV_TT‐RBD vaccine or CuMV_TT control on Day 42 measured by ELISA, LOG₁₀ OD₅₀ shown. (B) RBD‐specific IgA titer for the groups vaccinated with CuMV_TT‐RBD vaccine or CuMV_TT control on Day 42 measured by ELISA, OD₄₅₀ shown. (C) RBD‐specific IgA titer at Day 42 from mice immunized with CuMV_TT‐RBD vaccine, LOG₁₀ OD₅₀ shown. Plates in duplicates: treated with PBSTween or 7 M urea. (D) Avidity index of RBD‐specific IgA titer. Statistical analysis (mean ± SEM) using Student's t‐test. Control group n = 6, vaccine group n = 6. One representative of 2 similar experiments is shown