Alpha defensins

Defensins are a group of antimicrobial and cytotoxic peptides made by immune cells. There are seven defensins in humans, six alpha-defensins and one beta-defensin, which are involved in the innate immune defense at the surface of epithelia from the respiratory tract, the intestinal tract or the urinary tract. 

Satchell DP, Sheynis T, Shirafuji Y, Kolusheva S, Ouellette AJ, Jelinek R. Interactions of mouse Paneth cell alpha-defensins and alpha-defensin precursors with membranes. 

Paneth cells contribute to the maintenance of the gastrointestinal barrier, by secreting a number of antimicrobial molecules (alpha-defensins or cryptidins), as well as lysozyme and phospholipase A2. Their location, adjacent to crypt stem cells, suggests they have a role in defending epithelial cell renewal. 

Schmidtchen A, Frick IM, Bjorck L. Dermatan sulphate is released by protei-nases of common pathogenic bacteria and inactivates antibacterial alpha-defensin. Mol Microbiol 2001 39 708-713. 

Budihina, A.S, Pinegin, B.V. (2008) Alpha-defensins - antimicrobial peptides of neutrophil properties and function (in Russian). Russian Journal of Immunology, 29 (5), 317-320. 

Smith, J.G., andNemerow, G.R. (2008) Mechanism of adenovirus neutralization by Human alpha-defensins. Cell Host Microbe i 11 19. 

FALCO A, MAS V, TAFALLA c, PEREZ L, COLL JM, ESTEPA A. Dual antiviral activity of human alpha-defensin-1 against viral haemorrhagic septicaemia rhabdo-viras (VHSV) inactivation of vims particles and induction of a type I interferon-related response. Awftviro/ Res 2007 Nov 76(2) lll-23. 

CHANG TL, VARGAS J, JR., DELPORTILLO A, KLOTMAN ME. Dual role of alpha-defensin-1 in anti-HIV-1 innate immnnity. J Clin Invest 2005 Mar 115(3) 765-73. 

TANG YQ, YUAN J, osAPAY G, osAPAY K, TRAN D, MILLER CJ, et al. A cyclic antimicrobial peptide prodnced in primate lenkocytes by the hgation of two truncated alpha-defensins. Science 1999 Oct 15 286(5439) 498-502. 

FALCO A, BROCAL I, PEREZ L, COLL JM, ESTEPA A, TAFALLA C. In VIVO modulation of the rainbow trout (Oncorhynchus mykiss) immune response by the human alpha defensin 1, HNPl. Fish Shellfish Immunol 2008 Jan 24(l) 102-12. 

Defensins are variably cationic, relatively arginine-rich, nonglycosylated peptides comprised of 29-34 amino acid residues. Human (HNP-1) and rabbit (NP-5) defensins have been studied by NMR techniques and showed that they are rich in beta sheet structure. Although both types of defensins permeabilize the outer membrane of E. coli [31], they differ from other peptides with similar action but rich in alpha helices such as magainin, mellitin and cecropin. 

Mukae H, Ishimoto H, Yanagi S, et al. Elevated BALE concentrations of alpha- and beta-defensins in patients with pulmonary alveolar proteinosis. Respir Med 2007 101(4) 715-721. 

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