Since priming at a young age led to the typical magnitude and quality of influenza-specific CD8+ T cell responses following viral infection in the aged mice, we asked whether priming the mice via a non-replicative route (i.p. priming with 1.5×107 pfu of PR8) at extreme age (22 months) would be also beneficial for the subsequent influenza virus infection. This evidence concerns the gene CD8A and influenza.