Fig. 5: CD103⁺ T_RM-Tregs exerted immuno-suppressive but not pro-fibrotic roles in the progression of silicosis.

a Experiment design for CD103 neutralizing: silicotic mice treated with FTY720 (D28– D56 20 μg i.p.) together with CD103 neutralizing or isotype antibodies (100 μg/time i.v.) at indicated time points. b FC analysis of CD4⁺ T_RM cells for CD69 and CD103 expressions. The bar graph compared the ratios of CD103^– to CD103⁺ in the CD69⁺ CD4⁺ T_RM cells. c and d H&E staining to the lung sections of silicotic mice treated with FTY720 together with CD103 neutralizing or isotype antibodies. Scale Bar = 500 μm (left) and 200 μm (right). e and f FC analysis of the percentages and numbers of T-bet⁺ or ROR-γt⁺ in pulmonary CD4⁺ T_RM cells. g Flow histogram compared MFI of Ki-67 in the CD4⁺ T_RM-Teff cells. Bar graph displayed the MFI. h The schematic diagram describes the process of CD103⁺ T_RM-Tregs (CD4⁺ CD44⁺ FOXP3^YFP+ CD103⁺) sorted in 8 weeks post-CS-treated FOXP3^YFP mice by the FACS method. CS-pre-challenged mice were i.v. transferred with the sorted CD103⁺ Tregs or PBS. The recipient mice were analyzed 14 days after cell transfer. i H&E staining to the lung sections of distinct groups. Scale Bar = 600 μm (left) and 300 μm (right). The graph shows the inflammation score. j Masson’s trichrome staining to the lung sections of different groups. Scale Bar = 600 μm (left) and 300 μm (right). The bar graph showed the fibrosis-positive area. k Relative mRNA levels of Col1a1 and Fn in each group. l, m Relative mRNA levels of Il17a, Ifng, Tnfa, Il10 (l), and Tgfb1 (m) in each group. n FC analysis of the ratios and counts of IL-17A⁺ and IFN-γ⁺ in CD4⁺ T cells. For panels a–g, n = 4–5 biologically independent animals. For panels i–n, littermate mice were used, n = 4 biologically independent animals. N number also indicated independent experimental replicates. Individual mice are plotted on the graphs. The black line indicates the data were analyzed in parallel. Values are reported as the mean ± SD. P value was determined by unpaired two-tailed Student’s t-test or paired two-tailed Student’s t-test.