Panel A shows an experimental schematic where mice were immunized and co-housed with infected index mice, treated with FTY720 or PBS. Panel B presents bioluminescence curves for different groups of contact mice following co-housing. Panel C displays the probability of infection for immunized contact mice. Panel D shows another experimental schematic involving MT minus slash minus mice immunized and co-housed with infected index mice. Panel E presents bioluminescence curves for MT minus slash minus mice immunized with different treatments. Panel F shows the probability of infection for MT minus slash minus contact mice. Panel G depicts an experimental schematic assessing the role of CD4 and CD8 T cells in immunized contact mice. Panel H presents bioluminescence curves for contact mice treated with different antibodies. Panel I shows the probability of infection for immunized contact mice treated with different antibodies. Panel J displays example flow cytometry plots of isotype and anti-CD8 treated mice. Panel K shows a correlation between the area under the curve of the bioluminescence signal and the number of specific T cells in the nasal cavity.
Circulating immune cells, B cells, and CD4 T cells are not necessary to prevent infection from transmission when CD8 TRM are present. (A) Experimental schematic where Ad-FluNP i.n. or Ad-SenNP i.n. immunized contact mice were co-housed with Sendai-Luc–infected index mouse and treated with FTY720 or PBS control i.p. (B) Bioluminescence curves of Ad-FluNP i.n. (n = 8), Ad-SenNP i.n. with PBS (n = 16), and Ad-SenNP i.n. with FTY720 (n = 20) contact mice following co-housing with index mice. (C) Probability of infection for immunized contact mice, calculated as the proportion of contact mice that became infected. (D) Experimental schematic where μMT−/− mice were immunized i.n. with Ad-FluNP or Ad-SenNP prior to co-housing with Sendai-Luc–infected index mouse. (E) Bioluminescence curves of μMT−/− mice immunized with Ad-FluNP (n = 10) and Ad-SenNP (n = 12). (F) Probability of infection for μMT−/− contact mice immunized with Ad-FluNP and Ad-SenNP. (G) Experimental schematic to assess the role of CD4 and CD8 T cells where Ad-SenNP i.n. immunized contact mice were administered anti-CD4 or anti-CD8–depleting monoclonal antibody every 3 days, starting 1 day prior to co-housing with a Sendai–Luc–infected index mouse. (H) Bioluminescence curves of contact mice (n = 16/group) immunized with Ad-SenNP and treated with isotype control, anti-CD4, or anti-CD8 antibodies. (I) Probability of infection of immunized contact mice. (J) Example flow cytometry plots of isotype- and anti-CD8–treated mice at the conclusion of co-housing. Plots show CD69 and CD103 expression gated on IV− SenNP+ CD8+ T cells in the nasal cavity. (K) Correlation between the AUC of the bioluminescence signal from Sendai-Luc infection and the number of SenNP+ CD69+ CD103+ remaining in the nasal cavity after anti-CD8 depletion. For B, E, and H, solid dark lines represent means, solid pale lines represent individual mice, dashed grey lines represent the limit of detection, and dashed red lines represent the threshold of infection. Error bars (B–I) represent 95% binomial confidence intervals. Data are combined from at least two independent replicates. Statistical significance was determined using a two-sided Mann–Whitney test (C, F, and I) and nonparametric Spearman correlation (K), with ***P < 0.001, ****P < 0.0001, and NS for not significant.