Decreased number of antigen-specific CD8⁺ T cells in <i>Btla</i>^−/− mice after LM-OVA infection.

<p>A- WT and <i>Btla</i>^−/− mice were orally infected with 1×10⁹ LM-OVA and 7 days p.i., OVA-specific CD8⁺ T cells were detected by staining spleen cells with OVA-tetramer (K^b/OVA_257–264). The percentage and absolute number of OVA-tetramer⁺ CD8⁺ T cells found in WT (circles and open bars) and <i>Btla</i>^−/− (squares and filled bars) mice are shown. Each symbol represents an individual mouse from a total of 11–14 mice per group, pooled from three independent experiments. B- IFNγ production by CD8⁺ T cells isolated from WT and <i>Btla</i>^−/− mice, 7 days p.i., was calculated by intracellular staining after <i>ex vivo</i> stimulation of the cells with OVA_257–264 peptide. The percentage and absolute number of IFNγ⁺CD8⁺ T cells is shown. Data shown correspond to the average of 4–6 mice per group and are representative of three independent experiments. C- OVA-tetramer staining in MLN cells and IEL isolated from LM-OVA infected animals, 7 days p.i. Data pooled from three independent experiments are shown. D- Reduced number of memory CD8⁺ T cells in <i>Btla</i>^−/− mice. The percentage and absolute number of OVA-specific memory CD8⁺ T cells in the spleen of LM-OVA-infected animals was calculated by staining cells with OVA-tetramers, 70 days p.i. E- IFNγ intracellular staining performed on CD8⁺ T cells isolated from infected mice 70 days p.i., restimulated <i>ex vivo</i> with OVA_257–264 peptide. Data shown correspond to the average of 4 mice per group and are representative of three independent experiments.