For both heterotypic and homotypic influenza infections, CD8+ T cells of μMT mice had higher coexpression of PD-1, LAG-3, and TIM-3 compared with WT; however, this coexpression was greater in heterotypic infection compared with homotypic infection for both WT and μMT mice (Supplemental Figure 6I). This evidence concerns the gene LAG3 and infection.