CAMP and colitis: Mice produce the cathelicidin-related antimicrobial peptide (CRAMP) encoded by the Camp gene.26 Cathelicidin is secreted as a pro-peptide and cleaved by serine proteases, and the released C-terminal fragment is antimicrobial against Gram-negative bacteria.27,28 Cathelicidin is protective against A/E pathogens, as mice genetically deficient in cathelicidin (Camp-/-) exhibit exacerbated colitis and delayed clearance of C. rodentium23,29,30 and Escherichia coli O175:H7 31.