Institut Pasteur, Unité Macrophages et Développement de l'Immunité, Département de Biologie du Développement, Paris, France.
J Cell Sci. 2011 Sep 15;124(Pt 18):3053-9. doi: 10.1242/jcs.082792. Epub 2011 Aug 24.
The early control of potentially invading microbes by our immune system primarily depends on its main professional phagocytes - macrophages and neutrophils. Although the different functions of these two cell types have been extensively studied, little is known about their respective contributions to the initial control of invading microorganisms before the onset of adaptive immune responses. The naturally translucent zebrafish larva has recently emerged as a powerful model vertebrate in which to visualise the dynamic interactions between leukocytes and microbes in vivo. Using high-resolution live imaging, we found that whereas macrophages efficiently engulf bacteria from blood or fluid-filled body cavities, neutrophils barely do so. By contrast, neutrophils very efficiently sweep up surface-associated, but not fluid-borne, bacteria. Thus the physical presentation of unopsonised microbes is a crucial determinant of neutrophil phagocytic ability. Neutrophils engulf microbes only as they move over them, in a 'vacuum-cleaner' type of behaviour. This context-dependent nature of phagocytosis by neutrophils should be of particular relevance to human infectious diseases, especially for the early phase of encounter with microbes new to the host.
我们的免疫系统对潜在入侵微生物的早期控制主要依赖于其主要的专业吞噬细胞——巨噬细胞和中性粒细胞。尽管这两种细胞类型的不同功能已被广泛研究，但对于适应性免疫反应出现之前它们各自对入侵微生物的初始控制的贡献，人们知之甚少。最近，天然半透明的斑马鱼幼虫成为一种强大的模式脊椎动物，可用于在体内可视化白细胞与微生物之间的动态相互作用。通过高分辨率活体成像，我们发现巨噬细胞能够有效地从血液或充满液体的体腔中吞噬细菌，而中性粒细胞则几乎不能。相比之下，中性粒细胞能够非常有效地清除表面相关的但不是流体传播的细菌。因此，未被调理的微生物的物理呈现是中性粒细胞吞噬能力的关键决定因素。中性粒细胞只有在它们移动过微生物时才会吞噬微生物，这种行为类似于“真空吸尘器”。中性粒细胞吞噬作用的这种依赖于上下文的性质对于人类传染病尤其相关，特别是对于宿主遇到新微生物的早期阶段。
