Overexpression of fibrinogen-like protein 2 protects against T cell-induced colitis

Figure 5 Fgl2^Tg Treg prevent proliferation of infiltrating T cells in the colon. CD3⁺ T cell proliferation in the MLN and colon were examined by Ki67 staining at week 14. Ki67⁺ cells were seen primarily in the cortex of the MLN of sham mice. Mice that received Teff had increased clusters of Ki67⁺ cells, primarily within the cortex. Mice that received fgl2^+/+ Treg also had significant numbers of Ki67⁺ cells, whereas mice that received fgl2^Tg Treg had similar numbers of Ki67⁺ cells as sham mice. Ki67⁺ cells were only seen in the colonic crypts of sham mice. Mice that were reconstituted with Teff alone had large numbers of Ki67⁺ cells both within the lamina propria and epithelium, coincident with areas of colonic inflammation. Mice that received fgl2^+/+ Treg had small foci of Ki67⁺ cells in the lamina propria and epithelium whereas no Ki67⁺ staining was seen in these areas in mice that received fgl2^Tg Treg. In all groups of mice colonic crypt cells stained positively for Ki67 as expected. Original magnification × 100. MLN: Mesenteric lymph nodes; Teff: Effector T cells; Treg: Regulatory T cells.