Department of Life Sciences, University of Trieste, Trieste 34127, Italy.
Biochem J. 2011 Jun 15;436(3):537-46. doi: 10.1042/BJ20101977.
β-Defensins are antimicrobial peptides that exert their host-defence functions at the interface between the host and microbial biota. They display a direct, salt- and medium-sensitive cidal activity, in vitro, against a broad spectrum of bacteria and fungi, and there is increasing evidence that they also play a role in alerting and enhancing cellular components of innate and adaptive immunity. Their interaction with biological membranes plays a central role in both of these types of activities. In the present study, we have investigated the interaction of fluorescently labelled hBD2 (human β-defensin 2) with monocytes, macrophages and iDCs (immature dendritic cells), observing a differential capacity to be rapidly internalized into these cells. Complementary microscopy techniques [TEM (transmission electron microscopy), optical microscopy and IR microspectroscopy] were used to explore the functional and biological implications of these interactions on iDCs. Short-term exposure to the peptide resulted in significant alterations in membrane composition and re-organization of the endomembrane system, with the induction of degranulation. These events may be associated with the antigen-presenting activities or the chemotaxis of iDCs, which appears to occur via both CCR6 (CC chemokine receptor 6)-dependent and -independent mechanisms.
β-防御素是一种抗微生物肽，在宿主与微生物群之间的界面发挥宿主防御功能。它们在体外对广谱细菌和真菌具有直接、盐敏感和介质敏感的杀菌活性，越来越多的证据表明，它们还在先天和适应性免疫细胞成分的警报和增强中发挥作用。它们与生物膜的相互作用在这两种类型的活性中都起着核心作用。在本研究中，我们研究了荧光标记的 hBD2（人β-防御素 2）与单核细胞、巨噬细胞和未成熟树突状细胞（iDCs）的相互作用，观察到它们具有快速内化进入这些细胞的不同能力。互补显微镜技术[透射电子显微镜（TEM）、光学显微镜和红外微光谱学]用于探索这些相互作用对 iDCs 的功能和生物学意义。短时间暴露于该肽会导致膜组成发生重大变化，内质网系统重新组织，并引发脱粒。这些事件可能与 iDCs 的抗原呈递活性或趋化性有关，这似乎通过 CCR6（CC 趋化因子受体 6）依赖和非依赖机制发生。
