IFNG and infection: Infection of unvaccinated mice with PbA moderately reduced the proportion and the number of IL-10-producing CD8T cells (control PbA: 2.2%, 134 × 103 cells, mean value), but remarkably increased the number of IFNγ-producing CD8T cells (control PbA: 2.6%, 160 × 103 cells, mean value) compared to in naive mice (IL-10: 3.9%, 329 103 cells, IFNγ: 0.2% and 18.3 × 103 cells, mean value) (Figure 7C–E).