CD4 and infection: Only on day 9 p.i. significantly higher levels of CD4+ T cells (low dose: 13.84 ± 2.34%; high dose: 25.65 ± 18.04%, Figure 2A) and CD8+ T cells (low dose: 13.04 ± 3.21%; high dose: 26.07 ± 8.13%, Figure 2C) were detected in the lung for both low dose (blue bars) and high dose (red bars) infection of IAV compared to uninfected controls (CD4+ T cells: 3.31 ± 0.57%; CD8+ T cells: 3.28 ± 0.59%, grey dots).