Figure 4.

Intranasal SynGEM protein stimulates IgG⁺ and IgA⁺ antibody-secreting cells (ASCs) in peripheral blood from volunteers administered low or high doses of SynGEM. (A–F) ASCs from peripheral blood at time points up to 28 days after boost were enumerated by B cell ELISpot. (G and H) There was no correlation between IgG⁺ ASC frequencies and F-specific serum IgG titers (G) or IgA⁺ ASC frequencies and F-specific nasal IgA titers (H). Median values are shown in red. *P < 0.05, ***P < 0.001, and ****P < 0.0001. PBMCs = peripheral blood mononuclear cells. Vaccinations are indicated by red triangles.