Fig. 1: Spontaneous immune system activation and autoantibody production upon loss of Ercc1 in monocyte-derived macrophages.

a, H&E stain of kidneys isolated from 8-month-old wild-type (WT) and Er1^Lyz2/− mice (n = 7−8, P = 0.0040). The magnification in each image is indicated, and black arrows point to large activated lymphocytes and plasma cells (inflammation score: 0: no/focal, 1: moderate, 2: intense). b, Antinuclear autoantibody (ANA) detection in the sera of 8−10-month-old WT and Er1^Lyz2/− mice by ELISA (n = 8−10, P = 0.0449). Autoantibody patterns of 8-month-old WT and Er1^Lyz2/− and 24-month-old WT (aged) mice are shown in Extended Data Fig. 1f,g. c−f,Flow cytometry analysis of 8-month-old WT and Er1^Lyz2/− splenocytes stained for plasma cell (CD19, CD138), monocyte-derived cell (CD11b⁺Ly6G⁻), CD4⁺ T cell (CD4) and regulatory T cell (CD4, CD25, FOXP3) markers. All bar plots show the total number of CD19⁺CD138⁺ plasma cells (n = 7, P = 0.0201). Myeloid cells (n = 4−5, P= 0.04) (c), CD4⁺ cells (n = 9−10, P = 0.0469) (d), regulatory T (T_reg) cells (n = 3, P = 0.0483) (e) and natural killer (f) and CD8⁺ T (g) cells (n = 4, P = 0.0004 and P = 0.0395). Representative scatter plots and gating strategies are shown in Extended Data Fig. 2d,f–i. h,Flow cytometry analysis of activated macrophages in spleens of 8-month-old mice using CD11b and Ly6G for gating in cells of monocytic origin (gating strategy in Extended Data Fig. 2f) and MHC-II and CD86 as antigen presentation markers. Representative scatter plots (top) as well as bar plots (bottom) depict the percentage of MHC-II⁺CD86⁺ macrophages. MFIs are shown in Extended Data Fig. 3c (n = 10, P = 0.0014). i, Graphs showing the percentage of memory CD4⁺ T cells in the spleens of 2-month-old, 6-month-old and 10-month-old WT and Er1^Lyz2/− mice as well as 24-month-old (aged) WT mice, quantified by flow cytometry analysis. Representative scatter plots for the activation status of T cells isolated from 10-month-old mice are included in the same figure, and representative plots for cells isolated from 2-month-old and 24-month-old mice are shown in Extended Data Fig. 3g (n = 3−7, P = 0.0311 and P < 0.0001). j, ELISA analysis for the detection of IFNγ in the supernatants of PMA and ionomycin-stimulated CD4⁺ T cells (n = 3, P = 0.0124). k, Bar plot displaying the expression levels of T-bet (MFI) in CD4⁺ T cells in 8-month-old WT and Er1^Lyz2/− spleens. A representative histogram plot can be found in Extended Data Fig. 3h (n = 4−5, P = 0.0182). l, Histogram showing the MFI of PD-1 inhibitory marker in the FOXP3⁻CD44⁺ population of WT and Er1^Lyz2/− CD4⁺ T cells in the spleen, at 10 months of age (n = 4, P = 0.0063). m, Adoptive transfer of WT or Er1^Lyz2/− BMDMs in young WT mice for a time period of 8−12 weeks, every 2 weeks (experimental scheme shown in top legt). The percentage of activated (CD44^hiCD62L^lo) CD4⁺ cells in the inguinal lymph nodes (LN) and the levels of antinuclear autoantibodies in the sera of WT mice receiving WT or Er1^Lyz2/− BMDMs are plotted (bottom left and right, respectively). Plasma cells (CD19⁺CD138⁺) in the spleens of WT mice receiving WT or Er1^Lyz2/− BMDMs are shown in Extended Data Fig. 4e (n = 5−8, P = 0.0374 and P = 0.0320). Representative scatter plots are shown in Extended Data Fig. 4d,e. Error bars indicate s.e.m. among replicates. *P ≤ 0.05 and **P ≤ 0.01 (two-tailed Student’s t-test). NS, not significant.

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