Panel A shows an experimental schematic with a timeline of events. Panel B presents flow cytometry plots of Nur77 expression in CD8 plus SenNP plus T cells from the nasal cavity, BAL, and lung at different time points. Panel C includes box plots showing the frequency of Nur77 positive CD8 positive SenNP positive T cells in the nasal cavity, BAL, and lung at D35, D35 plus 3, and D35 plus 6. Panel D features box plots comparing the frequency of Nur77 positive CD8 positive SenNP positive T cells between uninfected and infected mice. Panel E displays another experimental schematic focusing on T cell proliferation assessed by EdU incorporation. Panel F shows flow cytometry plots of EdU expression in CD8 positive SenNP positive T cells from the nasal cavity at different time points. Panel G includes box plots showing the frequency of EdU positive CD8 positive SenNP positive T cells in the nasal cavity, BAL, and lung at D35, D35 plus 3, and D35 plus 6. The graphs illustrate the activation and proliferation of antigen specific CD8 T cells in response to transmitted virus in different parts of the respiratory tract.
Antigen-specific CD8 T cells in the URT, but not LRT, become activated and proliferate in response to transmitted virus. (A) Experimental schematic in which Nur77GFP contact mice immunized i.n. with LAIV-SenNP were co-housed with a Sendai-Luc–infected index mouse and sacrificed at D35 + 0 (n = 10), D35 + 3 (n = 7), or D35 + 6 (n = 19). (B) Representative flow cytometry plots of Nur77 expression gated on IV− CD8+ SenNP+ T cells in immunized contact mice. (C) Frequency of Nur77+ IV− CD8+ SenNP+ T cells in the nasal cavity, BAL, and lung of immunized mice at D35 + 0, D35 + 3, and D35 + 6. Circles represent uninfected mice, and triangles represent infected mice by in vivo imaging. (D) Frequency of Nur77+ of IV− CD8+ SenNP+ T cells separated by infection status. (E) Experimental schematic to assess T cell proliferation, where PR8-SenNP i.n. immunized contact mice were injected with 1 mg EdU i.p. 1 day prior to sacrifice at D35 + 0 (n = 7), D35 + 3 (n = 12), or D35 + 6 (n = 12) after co-housing with index mouse. (F) Representative flow cytometry plots of EdU expression gated on IV− CD8+ SenNP+ T cells in immunized contact mice. (G) Frequency of EdU+ IV− CD8+ SenNP+ T cells in the nasal cavity, BAL, and lung of immunized contact mice at D35 + 0, D35 + 3, and D35 + 6. Data are combined from three (B–D) or two (F and G) independent replicates. Statistical significance was determined using a two-sided Mann–Whitney test with ***P < 0.001, and NS for not significant.