Defensin-6

Host-defense peptide that contributes to intestinal innate immunity and mediates homeostasis at mucosal surfaces by forming higher-order oligomers that capture bacteria and prevent microbial invasion of the epithelium. After binding to bacterial surface proteins, undergoes ordered self-assembly to form fibril-like nanonets that surround and entangle bacteria and thereby prevent bacterial invasion across the epithelial barrier. Entangles and agglutinates Gram-negative bacteria, such as E.coli, S.typhimurium and Y.enterocolitica, and Gram-positive bacteria such as L.monocytogenes, thereby protecting the intestine against invasion by enteric bacterial pathogens. Blocks adhesion of C.albicans to intestinal epithelial cells and thereby suppresses fungal invasion of epithelial cells and biofilm formation. Under reducing conditions and in an acidic environment similar to the intestinal milieu, exhibits inhibitory activity against anaerobic bacteria such as B.adolescentis, L.acidophilus and B.breve, as well as B.longum and S.thermophilus, possibly by leading to alterations in bacterial cell envelope structures. The disulfide-linked oxidized form exhibits negligible antimicrobial activity against Gram-negative and Gram-positive bacteria, as compared to the enteric defensin DEFA5.