NOD2 activation is sufficient to restore Th1 and Th17 cells in the PLNs of diabetes-resistant Abx-treated STZ-injected WT mice. Cells from the MLNs or PLNs of STZ-injected WT mice that were treated with a cocktail of Abx and supplemented or not supplemented with MDP were recovered and analyzed for total number of cells (A) and absolute numbers of CD4⁺ (B), CD8⁺ (C), Th1 (D), Th17 (E), and tolerogenic CD11b⁺CD103⁺ DCs (F) in the MLNs, or the frequency (G–I) and absolute numbers (J and K) of Th1 and Th17 cells inside the PLNs by flow cytometry. The total numbers of macrophages (L) and DCs (M) of Abx-treated STZ-injected WT mice supplemented or not supplemented with MDP were analyzed by flow cytometry. The production of IL-6 (N) and IL-12 (O) by macrophages in the PLNs of WT mice that were treated with MDP but did not receive any STZ injections, or Abx-treated, STZ-injected WT mice supplemented or not supplemented with MDP, was analyzed by flow cytometry. The results are expressed as the mean ± SEM (n = 4–6 mice per group). *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001; n.s. = not significant.