Figure S1 - Polyfunctional CD4+ T Cell Responses to Immunodominant Epitopes Correlate with Disease Activity of Virulent Salmonella

Optimization of cytokine expression in Salmonella-specific CD4+ T cells. C57BL/6 mice were infected orally with 1×107 virulent Salmonella Typhimurium and at day 14 post-infection the IFN-γ and TNF expression in Salmonella-specific CD4+ T cells was determined by intracellular staining after restimulation with peptide-loaded dendritic cells (DCs). (A) Titration of peptide dose. CD3+CD4+ T cells were stimulated with DCs (DC:T cell ratio = 1∶5) that were loaded with different concentrations of STM1540262–276 peptide or not loaded with peptide (medium). Graph shows the percentage of IFN-γ+TNF+ cells within the CD3+CD4+ T cell population plotted against the indicated peptide concentrations. (B) Titration of DC:T cell ratio. 4×105 CD3+CD4+ T cells were stimulated with different amounts of DCs that were loaded with 10 µg/ml STM1540262–276 peptide or not loaded with peptide (medium). Graph shows the percentage of IFN-γ+TNF+ cells within the CD3+CD4+ T cell population versus the different DC:T cell ratios. Shown are representative analyses of two independent experiments with three mice per experiment. (EPS)