CD8A and infection: Although absolute numbers of LCMV-specific CD8+ T cells were measurably reduced in old mice with or without latent MCMV-infection, we did not identify relevant functional or phenotypic differences between LCMV-specific CD8+ T cells from these four groups of mice with respect to cytokine production (IFNγ, TNFα), cytotoxicity measured by degranulation (i.e. CD107a-upregulation) or expression of activation markers like CD43 (not shown).