the sphingosine 1 phosphate receptor 1 s1p agonist ozanimod ameliorates ulcerative colitis yet its mechanism of action is unknown here we examine the cell subsets that express s1p in intestine using s1p egfp mice the regulation of s1p expression in lymphocytes after administration of dextran sulfate sodium dss after colitis induced by transfer of cd4 cd45rb cells and by crossing a mouse with tnf driven ileitis with s1p egfp mice we then assayed the expression of enzymes that regulate intestinal s1p levels and the effect of fty720 on lymphocyte behavior and s1p expression we found that not only t and b cells express s1p but also dendritic dc and endothelial cells furthermore chronic but not acute inflammatory signals increased s1p expression while the enzymes that control tissue s1p levels in mice and humans with inflammatory bowel disease ibd were uniformly dysregulated favoring synthesis over degradation finally we observed that fty720 reduced t cell velocity and induced s1p degradation and retention of naïve but not effector t cells our data demonstrate that chronic inflammation modulates s1p expression and tissue s1p levels and suggests that the anti inflammatory properties of s1pr agonists might not be solely due to their lymphopenic effects but also due to potential effects on dc migration and vascular barrier function.