Given that the influenza-specific CD8+ T cells generated following primary infection of aged mice were either of suboptimal functional quality (DbPA224+CD8+; Figure 3, Figure 4) or reduced in number (DbNP366+CD8+; Figure 1), the further question was whether there was any effect on cell surface activation phenotype [34], [40]–[42]. The gene discussed is CD8A; the disease is influenza.