Several AMPs can activate FPR2 and show anti-inflammatory effects via receptor activation26,27,36. Because the GI tract has the highest microbiota population in the body, the system maintains a high level of AMP production to maintain intestinal homeostasis. The most well-known AMP that binds to FPR2 is LL-37 (human; LL-37, murine; CRAMP). LL-37 is produced by immune cells and epithelial cells and maintains epithelial barrier integrity37. It protects the intestine from infection by inducing epithelial cell migration, producing growth factors and mucins, and decreasing epithelial cell apoptosis38. LL-37 can also regulate the mucosal immune system as well as epithelial cell activity.