Figure 3.

Epicutaneous CpG ODN induces memory CTL responses equivalent to primary influenza viral infection. C57BL/6 mice immunized with scOVA ± ecCpG ODN or intranasally infected with X31-OVA virus were challenged with PR8-OVA virus 30 days post-immunization. The BAL, lungs, and spleen were collected 3 days post-challenge for flow cytometric analysis and OVA-specific CD8 T cells were enumerated. (A) Representative flow cytometric plots of the B220⁻CD8⁺ population, gating for OVA tetramer⁺ CD8⁺ double-positive cells. (B) The percentage and (C) total number of OVA-specific cells among CD8⁺ T cells in the BAL, lungs, and spleen, including the negative controls of mice immunized with X31 and challenged with PR8. Bar graphs are showing the mean ± SD from a representative experiment from three independent experiments (n = 3–6). Statistical significance of all four groups was analyzed by one-way ANOVA test with a Tukey’s multiple comparison post hoc analysis. *p < 0.05.