Fig. 3.

Salmonella Typhi-specific responses by LPMC CD4⁺ T cells isolated from the TI of a Ty21a-vaccinated and an unvaccinated representative volunteer. Using a 14-color flow cytometry panel we studied the induction of cytokine/chemokine production (IFNγ, TNFα, IL-2, IL-17A and MIP1β) and up-regulation of CD107a expression in CD69⁺ CD4⁺ T_EM cells obtained from (A) Ty21a-vaccinated and (B) unvaccinated representative volunteers following an overnight stimulation with non-infected or S. Typhi-infected autologous EBV-B cells at 37°C, 5% CO₂. Anti (α)-CD3/CD28 beads (1 μl) and unstimulated cells were used as a positive and negative controls, respectively, in both volunteers. The percentages of positive cells in the gated regions are shown above their corresponding black boxes.