Fig. 5. Colonization of GF mice with A. muciniphila supports colonic Tan cells.

a Colonic Tan cells in 12 weeks old germ-free (GF) mice unmanipulated and mono-colonized with Akkermansia muciniphila. Graphs show the frequency and the total number of relevant CD4⁺ cells (each symbol represents an individual mouse, n = 5 of each type). b Colonization of TCRα^k/o with A. muciniphila but not with E. coli BL21 supports colonic Tan cells and Tregs. Dot plots show representative staining of colonic CD4⁺ cells in TCRα^k/o mice first pretreated with antibiotics, then gavaged with PBS (ctr) or indicated bacteria and finally injected with CD4⁺ Tn cells. Expression of CD44, Foxp3, and FR4/CD73 on gated CD4⁺ and CD4⁺Foxp3^GFP−CD44⁺ cells were examined 8 weeks after adoptive transfer. Symbols on summarizing graphs depict individual animals (n = 8 mice in each group). c Feeding of TCRα^k/o mice with grape seed extract that expands residual A. muciniphila increases the number of colonic Tregs and Tan originating from transferred Tn cells. Dot plots show typical Treg and Tan frequencies in PBS-fed control (left) and grape-seed fed mice (right). Graphs show Tan cell frequency and total numbers from individual mice (n = 7 mice in each cohort). Plots show representative data of one of three experiments. Statistical significance was calculated by ANOVA with Bonferroni correction. *p < 0.05, **p < 0.01, ***p < 0.001.