As seen in Fig. 9a (gating strategy: Supplementary Fig. 2k), the absolute number of gp33–41-specific TNF-α-positive CD8+ T cells, IFN-γ-positive CD8+ T cells and IFN-γ/TNF-α DP CD8 T cells per spleen was significantly lower in KO than in WT mice 8 days post-infection. This evidence concerns the gene CD8A and infection.