Figure 4.

Comparison of cellular immune responses induced by S377-588-Fc at different antigen doses. Mice were immunized without (0 µg) or with 1, 5, or 20 µg of S377-588-Fc, and splenocytes from 10 d post-last immunization were tested for MERS-CoV S1-specific T cell responses by flow cytometric analysis. The frequencies of IL-2-(upper left corner) and IFN-γ-(bottom right corner) producing cells were expressed as percentages of CD4⁺ (A) or CD8⁺ (B) T cells. The samples were tested in triplicate and presented as mean ± SD from 5 mice in each group.