Figure 6. Effects of miR-17 overexpression on Treg cell function in vivo.

(A) Percentage weight loss induced in Rag2^−/− mice injected i.v. with naïve CD4+ T cells alone (no Treg cells) or these cells and CD45.1⁺Treg cells co-transduced with a bicistronic retroviral miR-17 expression construct, Treg cells carrying empty vector or Treg cells co-transduced with Eos and miR-17 expression constructs. 8–10 mice were used in each group, and the means ± SD of 3 independent experiments are shown. (B) Representative photomicrography of the distal colon of Rag2^−/− mice after adoptive transfers described above. 8 weeks post-transfer, colons were harvested and processed for standard H/E staining and histological analysis. (C) H/E slides were scored in a blinded fashion and colon pathology was scored. Shown are the mean scores for each treatment group +/− SD from at least 3 independent experiments. (D) Colon infiltration by CD4+ T cells during colitis. Lamina propria-infiltrating leukocytes were recovered and the absolute number of original naïve T cells and congenically distinct Treg cells were determined and are represented as the mean +/− SEM. (E to J) Pro-inflammatory cytokine production by naïve T cells co-transferred with the indicated Treg cells. Intracellular IL-17 or IFNγ levels in naive CD4+ (CD45.2+) cells from the (E,F) spleen, (G,H) mesenteric LNs, and (I,J) lamina propria of recipient mice were observed after re-stimulation of the recovered cells. Panels F, H, and J present the mean (± SEM) of three trials, while E, G, and I are representative dot plots.