Activated CD8 T cells in FOXO3−/− mice display decreased apoptosis.

<p>To address whether the increase in antigen-specific cells observed in FOXO3−/− mice at day 8 was in fact the result of decreased apoptosis, we assessed the relative expression levels of a number of cell survival or cell death markers. (<b>A</b>) Splenocytes isolated from day 6 PI mice were stained with anti-CD8, MHC-I tetramers and Annexin V directly ex vivo. Data is expressed as percentage of Annexin V positive cells amongst tetramer-binding CD8 T cells. Data are from at least two independent experiments with 4 mice/group/experiment; error bars represent the SEM and * indicates statistical significance at p<.005 (<b>B</b>) At day 6 PI, splenocytes from +/+ and FOXO3−/− mice were cultured for 6 hours with or without IL-15. After culture, cells were stained with MHC I tetramers, anti-CD8, anti-BIM, and anti-Bcl-2. The MFI of staining for BIM and Bcl-2 in tetramer-binding CD8 T cells was assessed by flow cytometry (left and middle); adjacent checkered bars are the MFIs with isotype control antibodies. In <b>B</b>, bar graphs on the right show the ratios of BIM:Bcl-2 MFI.