Figure 4. Durability of 4°M Trm Cells Enable Long-Lasting Heterosubtypic Protection.
(A) 120 days post-PR8-GP33 infection, mice bearing 1°M (blue) and 4°M (red) P14 cells were IN infected with 5 3 104 TCID50 X31-GP33. 4 days after the challenge, mice were euthanized, and lung virus titers were assessed.
(B) Prior to challenge influenza NP366-specific (left) and P14 (right) CD8+ T cell responses were evaluated in blood and expressed as percentage of total CD8+ T cells in peripheral blood. n = 8–10 mice/group. Representative of two independent experiments. Error bars represent mean ± SD. ***p = 0.0001, unpaired t test.
(C) Lung X31-GP33 virus titers measured in naive mice, and mice bearing 1°M (blue) or 4°M (red) P14 cells. n = 5–10 mice/group. Representative of two independent experiments. Error bars represent mean ± SD. *p = 0.0216, ****p < 0.0001, Kruskal-Wallis test. L.O.D., limit of detection.