抗菌肽在哺乳动物防御系统中的作用

抗菌肽是近年来发现的广泛存在于自然界的一类阳离子抗菌活性肽，它们在宿主先天性免疫和适应性免疫中有重要作用。多数抗菌肽具有分子小、带正电、两亲性、抗菌谱广等共同特点。防御素和calhelicidins是哺乳动物的两大主要抗菌肽家族，它们通过抵抗致病菌入侵为宿主提供了第一道防线而对宿主具有先天的抗菌防御功能，其中一些多肽对未分化的树突状细胞、淋巴细胞有趋化性，另外还有诱导细胞因子生成、肥大细胞脱粒等作用，从而表明这些多肽能动员并增强宿主的先天性免疫和适应性免疫。本文主要对哺乳动物抗菌肽的一般性质、基因及其表达、在宿主防御中的作用、作用机理及研究前景进行了概述。

The roles of antimicrobial peptides in mammalian defenses

Antimicrobial peptides are a recently discovered type of cationic antimicrobial activity peptides and are widely distrbuted in nature.They are important host-defense molecules of innate immunity and play a major role in innate and adaptive immunity.Most polypeptides share common features such as small size,cationic charge,an amphipathic nature and wide antimicrobial spectrum.Defensins and cathelicidins are the two major families of mammalian antimicrobial peptides.They provide a first line of defense against the invasion of microorganisms and contribute to host innate antimicrobial defense.Several members of these polypeptides are chemotactic to immature dendritic cells and lymphocytes,together with their other effects such as stimulating cytokine production and mast cell degranulation,these provide for their participation in mobilizing and amplifying innate and adaptive antimicrobial immunity of the host.In this review,we described mammalian antimicrobial peptides with respect to their properties,gene expression,their roles in host defense,mechanism of destroy bacteria,future research paradigms.