HLA-A and influenza: Fig 3 shows data from individual influenza challenge experiments (2–5 mice per experiment) in which splenic T cells from influenza PR8 infected mice were tested in IFNγELISpot for recognition of the influenza peptides depicted in Table 1 and Fig 1. Included is the known HLA-A*02:01 binding M(58–66) peptide [21] as a known positive control. As shown in Fig 3, reactivity was only observed against peptide M(58–66), suggesting that only this peptide is naturally processed during viral infection.