Tracking the temporal dynamics of GFI1 expression early in infection using Gfi1tdTomato/+ P14 CD8+ T cells showed that GFI1-tdTomato expression was significantly downregulated on day 2 and day 3 in P14 T cells isolated from spleen and mesenteric lymph nodes (mLN), respectively (Fig. 1e and Extended Data Fig. 1i,j). The gene discussed is CD8A; the disease is infection.