Figure 3.

Prenatal steroid treatment reduces insulitis and the incidence of T1D in NOD mice. (A) Schematic representation of the NOD mouse model. (B) Percentage of T1D-free NOD mice during 25 weeks of follow-up (n = 16–18 females per group). Gehan–Breslow–Wilcoxon test was used for statistical analysis. (C) Frequency of CD4⁺, Treg cells, CD8⁺, and DN splenocytes from female NOD mice at 6 weeks (n = 9–12 per group). (D) Comparison of Vβ chain usage between NOD offspring from betamethasone- (Bet) and sham-treated (PBS) dams at 6 weeks of age (n = 9–12 per group, female). Each T cell receptor (TCR) Vβ chain among CD4⁺ and CD8⁺ T cells is represented by a segment proportional in size to its frequency (which on average cover between 55 and 78% of all cells within the T cell subsets, the segment “other Vβ” indicates Vβ chain expression not covered by our panel of TCR Vβ chain-specific Abs). Segments marked with a star differ statistically significant between the groups (PBS or Bet), framed segments indicate TCR Vβ chains important for autoimmune disease in NOD mice. (E) Detailed results for the relevant TCR Vβ12 in CD4⁺ and TCR Vβ4 and Vβ6 in CD8⁺ spleen cells. N-way ANOVA was used for statistical analysis of TCR Vβ chain usage. (F) Representative H&E stained sections of pancreata from male and female T1D-free mice at sacrifice (25 weeks). (G) Insulitis score and (H) percentage of islets (presented as degree of infiltration: 0 = no insulitis, 1 = peri-insular inflammation, 2 = infiltration < 25%, 3 = infiltration 25–75%, 4 = infiltration > 75%) from non-diabetic male and female (n = 3 per group) NOD mice. Unpaired Student’s t-test was used for statistical analysis, *P < 0.05 and **P < 0.01.