The modulating effect of A. muciniphila-derived Amuc_1100 in colitis was associated with a reduction in infiltrating macrophages, CD8+ cytotoxic T lymphocytes, and pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1α, IL-6, IL-12, macrophage inflammatory protein-1 (MIP-1) α, granulocyte colony-stimulating factor, and chemokine (C-X-C motif) ligand 1 (CXCL1) in the colon. The gene discussed is CXCL1; the disease is colitis.