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多形态核中性白细胞(PMN)具有氧化和非氧化两种方式的杀菌机制,非氧化机制是由PMN细胞质中的苯胺兰颗粒的内源抗菌多肽介导的,这些抗菌分子包括防御素(defensin)、溶菌酶等。防御素富含精氨酸,非糖苷化多肽具29～34个氨基酸残基。不同动物的防御素均含有特异性的半胱氨酸区,有3个分子内二硫键。除存在于PMN中外,其它类型的细胞也可表达。防御素的同类物-cryptdin的cDNA最近已从鼠小肠细胞中被克隆。在感染和损伤后的某些昆虫的血淋巴中已测出类似于哺乳动物防御素的富含半胱氨酸的小分子抗菌肽
Polymorphic nucleated neutrophils (PMNs) have both bactericidal and oxidative mechanisms. The non-oxidative mechanism is mediated by the endogenous antimicrobial peptides of the aniline particles in the cytoplasm of PMNs. These antibacterial molecules include defensin ), Lysozyme and the like. Defensins are rich in arginine, non-glycosylated peptides with 29 to 34 amino acid residues. Defensins of different animals contain a specific cysteine region, there are three intramolecular disulfide bonds. In addition to being present in the PMN, other types of cells are also expressed. A similar product to defensin, the cDNA forcryptdin, has recently been cloned from mouse intestinal cells. Small-molecule, cysteine-rich antimicrobial peptides similar to mammalian defensins have been detected in the hemolymph of certain insects following infection and injury