Impaired suppressive function of BN^m Treg is involved in the development of intestinal lesions.

<p>(A) Absolute numbers of Foxp3+ CD4+ T cells in thymus, spleen and mLN from BN (n = 7) and BN^m (n = 13) rats. Data are representative of three independent experiments. (B) Suppressive activity of thymic CD25^bright CD4+ SP cells (top panel) and peripheral CD25^bright CD4+ T cells (bottom panel) from BN or BN^m rats was assessed in co-culture experiments with CFSE-labeled naive LEW CD4 T cells as effector cells. Proliferation was assessed by CFSE dilution (percentages indicate the proportion of CFSE^low cells). Data are representative of three independent experiments. (C, D) Disease frequency (C) and duodenum microscopic scores (D) in 12 week-old BN^m rats injected with PBS (white column or symbols; n = 21) or with 4.10⁶ BN CD25^bright CD4+ T cells (grey columns or symbols; n = 12) at 4 weeks of age. (E) Cytokine protein expression in duodenum from control BN^m rats with microscopic intestinal scores (white columns; n = 8) and from BN^m rats transferred with CD25^bright CD4+ T cells (grey columns; n = 12).