Comment

Following two recent review articles,1 ,2 readers ofGut will be aware of the increasing interest in the role of antimicrobial peptides in innate intestinal host defence.

Antimicrobial peptides of the defensin family were first isolated from neutrophils and macrophages in the 1980s and the expression of members of this family (designated cryptdins) in murine Paneth cells was subsequently reported.3-5 Based on the organisation of their disulphide bonds, the defensin family has been further subdivided into α and β defensins, with the human neutrophil defensins 1–4 (HNP 1–4) and murine cryptdins falling into the former group. Previous studies have shown that α defensins are synthesised as biologically inactive precursor molecules that require processing to the mature peptides that express antimicrobial activity.6 Normal murine Paneth cells contain mature forms of cryptdin,3-5implying that the enzyme that …