This finding was further elucidated by the finding [46] that butyrate was capable of arousing the expression of β-defensin 2 and β-defensin 3 in the colon and ileum of pigs, which eventually gave rise to protection against severe infection with E. coli. LL-37 expression was relying on butyrate activation of MEK–ERK pathway in the human colon cancer cell line SW620 [42], whereas p38/MAP kinase displays little effect on AMP production [42]. Here, MAP2K7 is linked to infection.