Rodríguez A, Esteban M A, Meseguer J
Department of Cell Biology, Faculty of Biology, University of Murcia, 30100, Murcia, Spain
Fish Shellfish Immunol. 2003 May;14(5):375-88. doi: 10.1006/fsim.2002.0446.
In this paper the possible involvement of the mannose-receptor on the non-specific recognition and phagocytosis of heat killed yeast cells (Saccharomyces cerevisiae) by gilthead seabream (Sparus aurata L.) head-kidney leucocytes was established by studying the ability of different sugars to inhibit the uptake of the yeast cells by leucocytes. Leucocytes were preincubated for 30min with different concentrations of sugar (alpha-mannan, d-mannose, d-fucose, l-fucose, d-glucose, d-glucosamine and n-acetyl-glucosamine, all of them described as specific ligands of the vertebrate mannose-receptor) and afterwards incubated with FITC-labelled yeast cells for phagocytosis assays. The phagocytic ability (percentage of cells with one or more ingested yeast cells within the total cell population) and capacity (number of ingested yeast cells per cell) of leucocytes was analysed by flow cytometry. The results demonstrate the potential existence of a specific receptor-sugar or receptor-yeast cell binding process, which was saturable, specific and dose-dependent. More specifically, when leucocytes were preincubated with appropriate doses of d-mannose, d- or l-fucose, d-glucose or n-acetyl-glucosamine the phagocytosis of yeast cells by head-kidney leucocytes was partially blocked. Seabream leucocytes were also preincubated with chloroquine, a lysosomotropic drug which downregulates (in a nonspecific manner) the expression of mannose-receptors in mammals, before phagocytosis assays were performed. The results demonstrated that the phagocytosis of yeast was completely blocked by this substance. The overall results seem to corroborate the presence of the mannose-receptor in seabream phagocytes, which is involved in the non-specific binding and phagocytosis of yeast cells by head-kidney leucocytes.
在本文中，通过研究不同糖类抑制酵母细胞被白细胞摄取的能力，确定了金头鲷（Sparus aurata L.）头肾白细胞表面的甘露糖受体可能参与了对热杀死的酵母细胞（酿酒酵母）的非特异性识别和吞噬作用。将白细胞与不同浓度的糖类（α-甘露聚糖、D-甘露糖、D-岩藻糖、L-岩藻糖、D-葡萄糖、D-葡糖胺和N-乙酰葡糖胺，所有这些都被描述为脊椎动物甘露糖受体的特异性配体）预孵育30分钟，然后与异硫氰酸荧光素标记的酵母细胞一起孵育以进行吞噬试验。通过流式细胞术分析白细胞的吞噬能力（在总细胞群体中摄取一个或多个酵母细胞的细胞百分比）和吞噬容量（每个细胞摄取的酵母细胞数量）。结果表明存在一种特异性的受体-糖类或受体-酵母细胞结合过程，该过程具有饱和性、特异性和剂量依赖性。更具体地说，当白细胞与适当剂量的D-甘露糖（D-或L-岩藻糖、D-葡萄糖或N-乙酰葡糖胺）预孵育时，头肾白细胞对酵母细胞的吞噬作用会部分受阻。在进行吞噬试验之前，金头鲷白细胞也用氯喹进行预孵育，氯喹是一种溶酶体促渗药物，它（以非特异性方式）下调哺乳动物中甘露糖受体的表达。结果表明，这种物质完全阻断了酵母的吞噬作用。总体结果似乎证实了金头鲷吞噬细胞中存在甘露糖受体，该受体参与头肾白细胞对酵母细胞的非特异性结合和吞噬作用。
