FIGURE 6.

Increased expression of IL-13⁺ and IFN-γ⁺ FoxP3⁺ CD25⁺ CD4⁺ T cells subsequent oral vaccination with Salmonella-CFA/I_IC (AP331). Spleens and HNLNs from SJL mice immunized with Salmonella vector (H647), Salmonella-CFA/I (H696), and AP331 strains were harvested 14 days post-immunization, and (A) FoxP3⁺ CD25⁺CD4⁺ T cells were analyzed by FACS (B, C) to determine their cytokine profiles by intracellular staining for IFN-γ, IL-10, IL-13, or cell-surface TGF-β expression. Splenic and HNLN FoxP3⁺ T_reg cells obtained from AP331-dosed mice shared features of both H647- and H696-immunized mice. Resembling H647-dosed mice, an elevated percentage of IFN-γ⁺ T_reg cells and a reduced level of TGF-β⁺ T_reg cells were obtained; resembling H696-dosed mice, an elevated percentage of IL-13⁺ T_reg cells was observed. The percent IL-10⁺ T_reg cells were the same for each immunized group and tissue evaluated. Insets in B represent the isotype control for intracellular cytokine staining. Depicted are the results from 6 – 9 mice/group: *, P < 0.001, **, P = 0.006, ***, P = 0.040, represent differences in cytokine-positive FoxP3⁺ T_reg cells from H647-vaccinated mice versus AP331- or H696-vaccinated mice. ^†, P < 0.001, represents differences in cytokine-positive FoxP3⁺ T_reg cells from AP331-vaccinated mice versus H696-vaccinated mice.