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. 2021 Jun 7;12(4):1311–1327. doi: 10.1016/j.jcmgh.2021.06.001

Figure 6.

Figure 6

LGG requires CD8 T cells to elicit a strong reduction of colonic tumors. (A) Graphic representation of the experimental outline for the induction of colonic tumors in C57BL/6 mice. Seven- to 8-week-old mice were injected with AOM before being subjected to 3 rounds of 1-week exposure to 2% DSS and a 2-week recovery period. After 3 cycles of DSS, and between weeks 8 and 10 of the experiment, tumors begin to form within the colonic epithelium of treated mice. Tumors were quantified by miniature colonoscope at week 10, before the start of treatment period at week 10, in which groups of mice were supplemented with HBSS, BC, or LGG, or by oral gavage daily for a total of 4 weeks period. Tumors were quantified further by miniature colonoscope at week 14, at the end of the 4-week treatment period. In addition, during the 4-week treatment period, groups of mice were administered either an anti-CD8 or an isotype control weekly for 4 weeks. Mice were killed at week 14. (B) Numeration of tumor burden as detected by mature colonoscopy at weeks 10 and 14 of mice described in panel A. (C) Quantification of tumor burden at death at week 14 after removal of colon and opening the colon longitudinally with visual examination of the colons of groups of mice described in panel A. (D) Representative images of colons bearing colonic tumor with red arrows denoting areas with tumors as evaluated by a pathologist. (E) H&E sections of Swiss-rolled colonic tissue at 14 weeks of mice described in panel A, with representative images of entire colon (upper panels) and high-powered view (lower panels) of the area shown in the rectangle of upper panels. (F) Quantification of dysplastic epithelium at 14 weeks of mice described in panel A. (G) Immunofluorescence analysis for the detection of CD8 T cell (green) DNA (blue) within colonic polyps at 14 weeks of mice described in panel A. (H) Quantification of CD8 T cells (green) within colonic polyps at 14 weeks of mice described in panel F. One-way analysis of variance used for statistics and represented as follows: ∗P < .05, ∗∗P < .01, and ∗∗∗P < .001. n = 9, 9, 8, and 10 for HBSS-isotype, LGG-isotype, HBSS-anti-CD8, and LGG-anti-CD8, respectively. DAPI, 4′,6-diamidino-2-phenylindole.