Fig. 4.

There were lower CD8 T cells within PBMC isolates and a reduced proportion of GrB+CD62L^high cells within CD8 T cells following virus stimulation in older adults compared to younger adults. A, Representative dot graphs of CD8 T cells from a younger and an older adult PBMC stimulated with A/Wyoming/03/2003 [A/H3N2] for 5 days showing an overall reduction in the proportion of the GrB+CD62L^high CD8 T cell subset in the older adult CD8 T cells. B, The mean percentage of CD8 T cells in fresh PBMC, and C, the mean percentage of the GrB+CD62L^high subset of the total CD8 T cell population in virus-stimulated PBMC, was significantly higher in younger (N=17) compared to older adults (N=119, p<0.001 for both comparisons). Error bars represent standard error.