FIGURE 1.

Induction of colitis in the absence of functional Foxp3. A, Weight change following the adoptive transfer of 4 × 10⁵ CD4⁺EGFP⁻Thy1.2⁺CD45RB^high T cells isolated from Foxp3^EGFP (dashed red lines; n = 47) and Foxp3^ΔEGFP (dashed black lines; n = 20) mice into Rag^−/− recipients. Control Rag^−/− littermates (gray lines; n = 11) did not receive transferred cells. Color-matched linear regression lines are plotted for each data set. B, Kaplan-Meier survival curves for the mice in A. C, Representative histological sections from the colons of randomly selected mice in A stained with H&E. D, Scatter plot showing the colitis score for each mouse where histology was obtained. E, Representative flow cytometry analysis of the mesenteric lymph nodes from each group (n = 7, 14, and 17, left to right). Numbers denote means for the adjacent gate. F, The total number of T_reg cells found in the mesenteric lymph nodes of healthy Foxp3^EGFP mice (green) and in mice with colitis with either functional (red) or nonfunctional (black) in situ-derived iT_reg cells. G, Representative data from in vitro suppression assays (n = 3) using sorted in situ-derived iT_reg cells (red), sorted nT_reg cells from healthy mice (green), or a 50:50 mix of each population (blue) to inhibit the anti-TCR-induced proliferation of unfractionated splenocytes. The ratio of T_reg cells to CD4⁺ responder splenocytes is indicated. H, Representative cell surface marker analysis of CD4⁺EGFP⁺ mesenteric lymph node T_reg cells from E above stained as indicated.