Antigen processing: Accessibility is the key


174 | DECEMBER 2001 | VOLUME 1 lowers body temperature. New findings published in the December issue of Nature Immunology show another benefit of sweating. Researchers led by Birgit Schittek show that human sweat contains a new antibiotic peptide called dermcidin. Anti-microbial peptides and proteins are components of the innate defence system. Proteins with anti-bacterial activities include phospholipase A2, lysozyme and granzyme B. Anti-microbial peptides include defensins, histatins and cathelicidins, some of which are in development as new anti-microbial agents. Some anti-microbial peptides and proteins are constitutively expressed, whereas others are induced during inflammation or by specific cytokines. While screening a subtracted complementary DNA library of skin cells, Schittek and colleagues isolated the gene encoding a new antimicrobial peptide, dermcidin. They analysed the sequence and found that the peptide has no homology with other known anti-microbial peptides. The protein is specifically and constitutively expressed in sweat glands and secreted Whether its the Scandinavian sauna, the Russian bania, the Turkish hamman or the American Indian sweatlodge, sweating is something we sometimes like to do. Sweating is also beneficial, as evaporation from the skin into sweat. Dermcidin is proteolytically processed, but it is not clear whether this processing takes place in the sweat gland cells or after it has been secreted into sweat. The purified peptide showed broad activity against pathogenic bacteria and fungi, which was maintained over a broad pH range and in high salt concentrations. These results show that human sweat contains at least one anti-microbial protein that might have a role in the regulation of skin flora and in innate immune responses. Unlike most anti-microbial peptides, such as defensins, which are enriched in arginine and lysine residues leading to a net positive charge, dermcidin has a net negative charge of –5. The mode of action of the cationic defensins is to bind to anionic components in the target membrane and kill the microorganims by pore formation and permeabilization of the cell membrane. It seems probable that the mode of action of dermcidin will differ, and it remains to be seen whether dermcidin will be active against microorganisms that are resistant to current antibiotic therapies. Melanie Brazil, Associate Editor, Nature Reviews Drug Discovery References and links ORIGINAL RESEARCH PAPER Schittek, B. et al. Dermcidin: a novel human antibiotic peptide secreted by sweat glands. Nature Immunol. 2, 1133–1137 (2001) Self-defence is a sweaty business I N N AT E I M M U N I T Y H I G H L I G H T S

DOI: 10.1038/35105015

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@article{Bell2001AntigenPA, title={Antigen processing: Accessibility is the key}, author={Elaine B. Bell}, journal={Nature Reviews Immunology}, year={2001}, volume={1}, pages={174-174} }