Furthermore, challenging a separate group of mice with an H5N1 virus (Figure 3b) demonstrated that, in the context of pathogenic influenza and the associated cytokine dysregulation, both CD4+ and CD8+ subsets together provide considerably more protection than either alone (75% survival in vaccinated, undepleted mice, 36% survival in CD4-depleted mice, 38% survival in CD8-depleted mice, 11% survival in dual-depleted mice, and 0% survival in naïve mice). This evidence concerns the gene CD4 and influenza.