Biotechnology Group, School of Engineering and Advanced Technology, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand.
Int J Antimicrob Agents. 2010 Mar;35(3):288-91. doi: 10.1016/j.ijantimicag.2009.10.017.
In in vitro co-culture experiments, the ovine-derived cathelicidin OaBac5mini showed antimicrobial activity against Escherichia coli cells and modulated production of a cytokine by a mammalian inflammatory cell type (macrophage). Using atomic force microscopy, the morphology of peptide-treated E. coli bacteria showed no cell lysis, indicating an intracellular mode of action of the peptide leading to bacterial cell inhibition. At a concentration of 50microg/mL OaBac5mini, the peptide suppressed production of the inflammatory cytokine interleukin-12 by murine J774A cells that had been stimulated with Staphylococcus aureus strain Cowan; levels of other cytokines were unaffected. Thus, certain cationic peptides can enter and disrupt invading Gram-negative pathogens and may be able to modulate inflammatory responses induced by Gram-positive bacterial products.
在体外共培养实验中，绵羊源抗菌肽 OaBac5mini 对大肠杆菌细胞表现出抗菌活性，并调节了哺乳动物炎症细胞类型（巨噬细胞）细胞因子的产生。原子力显微镜观察显示，经肽处理的大肠杆菌细胞形态无细胞裂解，表明该肽的作用方式为细胞内作用，从而抑制细菌细胞。在 50μg/ml 的浓度下，该肽抑制了金黄色葡萄球菌 Cowan 株刺激的鼠源 J774A 细胞产生炎症细胞因子白细胞介素-12；其他细胞因子水平不受影响。因此，某些阳离子肽可以进入并破坏入侵的革兰氏阴性病原体，并可能能够调节由革兰氏阳性细菌产物诱导的炎症反应。
