Dini L, Ruzittu M T, Falasca L
Department of Biology, University of Lecce, Italy.
Scanning Microsc. 1996;10(1):239-51; discussion 251-2.
Physiological elimination of unwanted cells within the organism occurs via cell death by apoptosis and phagocytosis of these cells represents a key event in the apoptotic process. Macrophages, which are the dedicated phagocytes, and other occasionally phagocytic cells ingest the apoptotic cells while they are still intact, thus preventing the leakage of potentially harmful materials from the dying cells. Although evidence has been presented that the elimination of apoptotic bodies from the tissue operates by means of specific recognition systems, the molecular mechanisms by which an apoptotic cell is recognized are poorly understood. Recent data indicate that phagocyte recognition of apoptotic cells involves at least four classes of receptors on the phagocyte surface. On the other side, dying cells may display different signals to signal their status. Exposure of phosphatidyl serine (PS) on the surface of apoptotic lymphocytes triggers their specific recognition and removal by macrophages. Apoptotic thymocytes are also identified by altered lipid packing on their surface. Different populations of macrophages use either the vitronectin receptor or the PS receptor to recognize and remove apoptotic cells. It has been suggested that the asialoglycoprotein and the galactose-specific receptors of healthy hepatocytes and sinusoidal liver cells are implicated in the engulfment of apoptotic hepatocytes, likely in cooperation with other hepatic carbohydrate-specific receptor systems. The purpose of this review is to examine current knowledge of the mechanisms by which phagocytes recognize and ingest apoptotic cells.
机体通过细胞凋亡对不需要的细胞进行生理性清除，而这些细胞的吞噬作用是凋亡过程中的关键事件。巨噬细胞作为专职吞噬细胞，以及其他偶尔具有吞噬作用的细胞，会在凋亡细胞仍保持完整时将其吞噬，从而防止死亡细胞中潜在有害物质的泄漏。尽管已有证据表明组织中凋亡小体的清除是通过特定识别系统进行的，但凋亡细胞被识别的分子机制仍知之甚少。最近的数据表明，吞噬细胞对凋亡细胞的识别涉及吞噬细胞表面至少四类受体。另一方面，垂死细胞可能会显示不同的信号来表明其状态。凋亡淋巴细胞表面磷脂酰丝氨酸（PS）的暴露会触发巨噬细胞对其进行特异性识别和清除。凋亡胸腺细胞也可通过其表面脂质排列的改变来识别。不同类型的巨噬细胞利用玻连蛋白受体或PS受体来识别和清除凋亡细胞。有人提出，健康肝细胞和肝窦状细胞的去唾液酸糖蛋白和半乳糖特异性受体可能参与凋亡肝细胞的吞噬过程，可能是与其他肝脏碳水化合物特异性受体系统协同作用。这篇综述的目的是探讨吞噬细胞识别和摄取凋亡细胞机制的当前知识。
