The secondary CD8 T cell response in FOXO3 deficient mice.
+/+ and FOXO3−/− mice were infected with LCMV-Armstrong and after 90 days PI, these mice were challenged with 2.5×106 PFU of LCMV clone 13. (A) Five days after LCMV clone13 infection, mononuclear cells from spleen, liver and lymph nodes were collected and the total number of LCMV-specific CD8 T cells was determined by staining with anti-CD8 and LCMV-specific MHC-I tetramers. Data are from 4–6 mice/group; error bars represent the SEM and * indicates statistical significance at p<.05. (B) Splenocytes from +/+ or FOXO3−/− mice were stained with anti-CD8, MHC-I tetramers and anti-Ki67. The percentage of Ki67 positive cells amongst tetramer positive CD8 T cells was determined by flow cytometry. (C) Splenocytes were stimulated ex vivo with LCMV-specific peptides for 5 hours. Following stimulation, cells were stained for surface expression of CD8 and intracellular expression of IFNγ, IL-2 and TNFα. The top number in the plots on the left is the MFI of staining for IFNγ. The bottom number in the plots indicates the percentage of total splenocytes that are CD8 and IFNγ positive. The plots on the right are gated on IFNγ+ve CD8 T cells and the numbers are the percentages of cells that produced IFNγ and IL-2, IFNγ and TNFα, or IFNγ, IL-2, and TNFα. (D) LCMV titers in serum and lung were determined by plaque assay using a vero cell monolayer. Each symbol represents the viral titer of an individual mouse.