Fig. 6. Antimicrobial therapy reduces activated moDC and T lymphocyte numbers in pIgR^−/− mice.

a Representative in situ hybridization (FISH) of bacterium invading the epithelial barrier in a small airway from an 8-month-old pIgR^−/− mouse. The bacterium (red arrow) is labeled by a FISH probe targeting prokaryotic 16s rRNA. IgA staining (green) shows absence of SIgA on the airway surface. b Percentage of airways with bacteria intercalated into the mucosa in WT and pIgR^−/− mice at indicated ages. c Quantification of moDCs, cDC1, and cDC2 cells (as % CD11c⁺MHCII^hi cells) in aged pIgR^−/− mice with and without antibiotics (vancomycin, neomycin, ampicillin, metronidazole, VNAM) treatment. d Percentage of moDCs (CD11c⁺MHCII^hiCD11b⁺CD64⁺) expressing the activation markers pRelA, TNFR1, and CD86 in the lungs of aged pIgR^−/− mice with and without antibiotic treatment. e, f Quantification of CD4⁺ and CD8⁺ T lymphocytes in the lungs of aged pIgR^−/− mice with and without antibiotic treatment. g Percentage of slide occupied by TLS in 18-month-old untreated WT and pIgR^−/− mice and 18-month-old pIgR^−/− mice treated with antibiotics. b *p < 0.01 compared to age-matched WT mice (2-way ANOVA with Bonferroni post hoc test); n = 5–11 mice/group. c *p < 0.01 compared to untreated pIgR^−/− mice (2-way ANOVA with Bonferroni post hoc test); n = 6–8 mice/group. d–e *p < 0.05 compared to untreated pIgR^−/− mice (t-test); n = 6–8 mice/group. Box-and-whisker plots represent median, interquartile range, and range. f *p < 0.001 compared to untreated pIgR^−/− mice (Mann–Whitney test); n = 6–8 mice/group. g *p < 0.01 compared to untreated pIgR^−/− mice (Mann–Whitney test); n = 6–8 mice/group.