Fig. 4: CD4⁺ cells are required to maintain expanded HER2⁺ DCCs after IAV infection.

a, Adjacent lung sections of IAV-infected mice at 28 dpi were stained for HER2 (green) and CD4 (magenta, left and middle) or HER2 (green) and CD8 (magenta, right). b, As in a for IAV-infected MMTV-Her2 mice at 28 dpi, but for a region lacking CD4⁺ cells. c,d, Lung sections of MMTV-Her2 mice without or with CD4 depletion starting at −1 dpi or 10 dpi and taken for analysis at 28 dpi were stained for HER2 (green) and DAPI (blue) (shown for CD4 depletion starting at −1 dpi) (c). The number of HER2⁺ cells was quantified (n = 4 per group) (d). e, Quantification of HER2⁺ cells from MMTV-Her2 mice with CD4, CD8 or CD4/CD8 depletion (on −1 dpi) at 28 dpi (n = 4 per group, n = 3 CD8 depletion). f, Lung sections of MMTV-Her2 and CD4-depleted MMTV-Her2 mice at 28 dpi were stained for HER2 (green), CD8 (magenta) and DAPI (blue). g, Heatmap of the top 20 differentially expressed genes from scRNA-seq comparing CD4⁺ effector T cells from MMTV-Her2 + IAV versus wild type + IAV mice at 15 dpi. h, GSEA analysis showing pathway enrichment in effector CD8⁺ T cells in CD4-depleted MMTV-Her2 + IAV versus control MMTV-Her2 + IAV mice at 15 dpi. i, Concentration of IFNγ in a supernatant of enriched CD8⁺ cells enriched from lungs of MMTV-Her2 mice with or without CD4 depletion at 15 dpi and activated by anti-CD3/CD28 antibody (n = 4 IAV + IgG, n = 3 IAV + anti-CD4). j, Ex vivo CD8⁺ cytotoxic assay in which HER2⁺ cells were incubated with the same CD8⁺ cells (n = 3 per group). Significance was determined by one-way ANOVA (d and e) or two-tailed Student’s t-test (i and j). All box-and-whisker plots are presented as maximum value (top line), median (middle line) and minimum (bottom line) with all data points shown as dots. Scale bars: a, 25 μm; b, c and f, 50 μm. All replicates are biological.

Source Data