Table 1.

The diversity of mammalian host defence peptides

Peptide family and structure	Subfamily	Expression and diversity
		Human	Mouse	Pig	Cow
Defensin	α-defensins	Neutrophils and other leukocytes	Paneth cells of the intestines Epithelial cells		No α-defensins
Amphipathic, cationic peptides Triple-stranded antiparallel β-sheet	Three disulphide bonds linking cysteines 1–6, 2–4, 3–5	Paneth cells of the intestines Mucosal epithelia, skin
	β-defensins	Mucosal epithelia and skin Monocytes, macrophages, dendritic cells	Epithelial cells	Epithelial cells	Epithelial cells Neutrophils and other leukocytes
	Three disulphide bonds linking cysteines 1–5, 2–4, 3–6
Cathelicidin	Non-applicable	LL-37 expressed by neutrophils, and other leukocytes mucosal epithelia, skin	CRAMP expressed by neutrophils, and other leukocytes mucosal epithelia, skin	Large variety: protegrins, PR-39, prophenins, etc. Expressed by neutrophils and other leukocytes	Large variety: bactenecin, BMAP, indolicidin, etc. Expressed by neutrophils and other leukocytes
Amphipathic, cationic peptides Diverse sequence and structure Cleaved from a cathelin-like precursor protein