IFNG and infection: To confirm that IAV-specific CD4 and CD8 T cells were Ifnγ+, we stained cells from IAV-infected reporter mice with MHC I and MHC II tetramers containing immunodominant IAV nucleoprotein (NP) peptides, NP368-74, and NP311-325, respectively at days 10 and 40 post-infection (Fig. 5A and B).