S1pr1 ^iΔLEC mice do not develop epithelial dysplasia, ileal inflammation, or microbial dysbiosis. (A and B) The ileum of S1pr1^f/f and S1pr1^iΔLEC mice (TM@8w) were sectioned and analyzed by H&E (A) or IHC for the indicated markers (B). (A) The intestinal epithelium of S1pr1^iΔLEC mice appeared to be indistinguishable from control samples with no obvious infiltration of immune cells. (B) The same number of CD45⁺ hematopoietic cells, B220⁺ B cells, and S100A9⁺ neutrophils were observed in the control and S1pr1^iΔLEC mice. (C) The serum from S1pr1^f/f and S1pr1^iΔLEC mice was analyzed by multiplex ELISA for inflammatory cytokines. IL-7 was modestly increased in the S1pr1^iΔLEC mice. No significant differences were observed between the control and S1pr1^iΔLEC mice for the other cytokines. (D) The fecal pellets of S1pr1^f/f and S1pr1^iΔLEC mice were analyzed by shotgun metagenomic analysis. The numbers on top of the graphs indicate the number of bacterial reads. The same information is provided within brackets as a percentage of total reads. The graphs indicate the relative abundance of the bacterial species. No obvious change was observed between the S1pr1^f/f and S1pr1^iΔLEC mice. The inset is a hierarchical clustering of the same samples with the co-housed mice within red boxes. Three of the four co-housed mice appear to be closer to each other irrespective of their genotype. Statistics: (A and B) n = 4 control and n = 5 S1pr1^iΔLEC mice (TM@8w). Two to four sections per mice were analyzed, and the number of cells per crypt-villus unit was calculated, and graphs were plotted as mean ± SEM. Statistical significance was calculated using unpaired t test for CD45 and S100A9 and Mann–Whitney test for B220; (C) n = 8 control and n = 10 S1pr1^iΔLEC mice (TM@8w). Graphs were plotted as mean ± SD. Significance was determined using unpaired t test with Welch’s correction for MCP-1 and RANTES and Mann–Whitney test for the other cytokines. (D)n = 2 male S1pr1^iΔLEC (TM@P1–7) and n = 3 TM-treated S1pr1^f/f control littermates. In the distance plot, cohoused mice are within the red box. *P < 0.05.