Fig. 2

Contribution of memory phenotype cells from naïve aged mice to new infections. a Sorted CD44^Low CD8 T cells from naïve aged mice (18–22 months) were co-transferred with sorted CD44^High CD8 T cells from naive aged mice in a 1:1 or a 1:9 ratio, with CD8 T-cell depleted splenocytes from young mice (2–3 months), into T cell deficient TCR βδ−/− mice. The mice were infected with influenza virus, and the responding CD8 T cells originating from naïve or memory donors analyzed at 12 days post infection. b Flow cytometry gating strategy used to identify the donor populations in the lung: distinguished by CD90.2⁺CD45.2⁺ cells for donor aged C57BL/6, CD90.2⁺CD45.2⁻ for donor aged B6.CD45.1, and CD90.2⁻CD45.2⁺ for donor young B6.CD90.1. c The response of donor naïve and memory CD8 T cells is shown for the 1:1 transfer (left) and the 1:9 transfer (right). d The epitope-specificity of the donor naive and memory CD8 T cell response, indicated by colors, is shown for the 1:1 transfer (left), the 1:9 transfer (right), and the memory response from intact wild type (WT) mice (middle). The data represent two independent experiments