tailieunhanh - Báo cáo khóa học: Collectins Players of the innate immune system

Collectins are a family of collagenous calcium-dependent defense lectins in animals. Their polypeptide chains consist of four regions: a cysteine-rich N-terminal domain,a colla-gen-like region,ana-helical coiled-coil neck domain and a C-terminal lectin or carbohydrate-recognition domain. These polypeptide chains form trimers that may assemble into larger oligomers. The best studied family members are the mannan-binding lectin,which is secreted into the blood by the liver,and the surfactant proteins A andD,which are secreted into the pulmonary alveolar and airway lining fluid | Eur. J. Biochem. 271 1 Í -1 9 2004 FEBS 2004 doi REVIEW ARTICLE Collectins Players of the innate immune system J. Koenraad van de Wetering Lambert M. G. van Golde and Joseph J. Batenburg Department of Biochemistry and Cell Biology Graduate School of Animal Health Faculty of Veterinary Medicine Utrecht University the Netherlands Collectins are a family of collagenous calcium-dependent defense lectins in animals. Their polypeptide chains consist of four regions a cysteine-rich N-terminal domain a collagen-like region nn a-helical coiled-coil neck domain and a C-terminal lectin or carbohydrate-recognition domain. These polypeptide chains form trimers that may assemble into larger oligomers. The best studied family members are the mannan-binding lectin which is secreted into the Ilkxxl by the liver and the SLH i adint p1 oseins A mid D winch are secreted into the pulmonary alveolar and airway lining fluid. The collectins represent an important group of pattern recognition molecules which bind to oligosaccharide structures and or lipid moities on the surface of microorganisms. They bind preferentially to monosaccharide units of the mannose type whích presen t two viciizil hydroxyl groups in an equatorial position. High-affinity interactions between collectins and microorganisms depend on the one hand on the high density of the carbohydrate ligands on the microbial surface and on the other on the degsee of oligomerization of the collectin. Apart from binding to microorganisms hire collectins can interact with receptors on host cells. Binding of collectins to microorganisms may facilitate microbial clearance through aggregation complement activation opsoni-zation and activation of phagocytosis ndd ãhi ĩitĩtim oI microbial growth. In addition the colleciíns zan noxh-lhtre inflammatory and allergic responses affect ílk tptotic eell clearance and modulate the adaptive immune system. Keywords collectin - tyee lectin mnnunn-i iniinng lectin MBL