Figure 3.

Proliferation of OVA-specific CD4⁺ T cells in the NALT following immunization with flagellin-OVA fusion protein. NALT were harvested three days following i.n. immunization with ovalbumin, flagellin plus ovalbumin, or flagellin-ovalbumin fusion protein. (A) CFSE dilution by OVA-specific CD4⁺ T cells was measured by flow cytometry. Plots are gated on CD4⁺ lymphocytes. Numbers convey the percentage of OVA-specific cells in each condition that underwent at least one division prior to harvest (B) Intranasal instillation of flagellin-ovalbumin stimulated significantly higher levels of antigen-specific cell population expansion in the NALT (p < 0.003) and LN (p < 0.001) relative to mice immunized with ovalbumin. The absolute numbers of OVA-specific CD4⁺ T cells recovered from the NALT (** p = 0.003) and LN (*** p < 0.001) of mice immunized with flagellin-ovalbumin was significantly higher than the number of cells recovered from mice immunized with ovalbumin or ovalbumin plus flagellin as separate proteins (p < 0.01 for NALT and p < 0.05 for LN). An average of 140 and 5100 CD90.1⁺ cells were recovered from the NALT and LN, respectively, of mice immunized with ovalbumin only. * denote the level of significant difference are appear lower in the figure legend. An average of 4200 and 37,000 CD90.1⁺ cells were recovered from the NALT and LN, respectively, of mice immunized with flagellin-ovalbumin. Results shown were generated from one experiment with three mice per group and representative of a total of six mice per condition across two independent experiments.