Fig. 5: AT2s exhibit a globally restricted capacity to present influenza virus epitopes via MHCII.

a Hybridoma presentation assay. b, c Presentation of MHCII-restricted flu peptides by B6 AT2s and a mixed population of CD11c⁺ and CD19⁺ lung cells (b) or BALB/c AT2s and CD11c⁺ lung cells (c) sorted from naive mice then incubated with synthetic peptide (dark gray), live virus (black), or no antigen (light gray), reflected by NFAT-LacZ-inducible T cell hybridoma activation and cleavage of a fluorogenic β-galactosidase substrate. Symbols shown represent technical replicates with n = 3 per condition, and bars reflect mean plus SEM. Data are from one experiment (b, c), which is representative of three similar independent experiments for (b). d Primary T cell ELISpot presentation assay. e Presentation of MHCII-restricted flu peptides by lung AT2s and CD103⁺ CD11c⁺ APCs sorted from naive or flu-infected B6 WT (blue) or MHCII^−/− (black) mouse lungs 4 dpi, measured as the production of IFN-γ by responding flu-experienced splenic CD4⁺ and CD8⁺ T cells (as indicated); “APC %flu+” numbers describe the proportion of each APC type that was flu-infected (shown in Supplementary Fig. 4b). Symbols shown represent technical replicates from one experiment, representative of two similar independent experiments. Technical replicates displayed are: n = 3 for WT naive AT2 + CD4, and WT and MHCII^−/− 4 dpi CD103⁺ CD11c⁺ + CD4 conditions; n = 2 for MHCII^−/− naive AT2 + CD4, WT and MHCII^−/− 4 dpi AT2 + CD4 conditions; n = 1 for WT and MHCII^−/− 4dpi AT2 + CD8 conditions, WT and MHCII^−/− naive CD103⁺ CD11c⁺ + CD4 conditions, and WT and MHCII^−/− 4 dpi CD103⁺ CD11c⁺ + CD8 conditions. Bars represent averages of technical replicates for all conditions where n = 2–3, and single values where n = 1. Source data are provided as a Source data file.