Of note, the exponential relationship (i.e., the scale of CD8+ T cell level or recovery time) is only a qualitative one, as we have no way to determine the scaling between different x-axis measurement units, nor adjust for particular host and/or viral factors that differ between the two experiments (i.e., H3N2-infection in the mouse (38) versus H7N9 infection in humans (21)). The gene discussed is CD8A; the disease is infection.