PBMC collected from Ty21a vaccinees (n=16) were stimulated ex-vivo with Salmonella-infected targets. Peak post-vaccination increases in single (S) and multifunctional (MF) IFN-γ+, CD107a+, TNF-α+ and IL2+ cells specific for S. Typhi (A)-, S. Paratyphi A (B)- and S. Paratyphi B (C)-infected targets were measured in CD4+T EMRA subsets. Salmonella-infected targets specific CD4+ TEMRA MF cells were further subdivided into 11 different subsets based on the possible combinations of simultaneous production IFN-γ, TNF-α and/or IL-2- and/or expression of CD107a using the FCOM analysis tool. Shown are the post-vaccination peak increases in the 5/11 dominant subsets and sum of the remaining 6/11 (Others) subsets of specific MF cells. Data are presented as mean percentages of total MF cells for each subset and “Others” in Ty21a vaccinees (n=16).
T EMRA, CD45RA+ T effector/memory; Post vaccination increase: Peak level at days 42 or 84 post-vaccination minus the corresponding pre-vaccination levels
***p<0.001 **p<0.01. *p<0.05 compared with corresponding single-positive cells by Wilcoxon signed rank test, two tailed. (A–C).
No statistical significant differences were observed among the various subsets with nonparametric one-way ANOVA (D–F).