IMMUNOCYTOCHEMICAL CHARACTERIZATION OF THE ENDOCYTIC AND PHAGOLYSOSOMAL COMPARTMENTS IN PERITONEAL-MACROPHAGES
IMMUNOCYTOCHEMICAL CHARACTERIZATION OF THE ENDOCYTIC AND PHAGOLYSOSOMAL COMPARTMENTS IN PERITONEAL-MACROPHAGES
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DOI：
10.1083/jcb.116.1.95
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发表时间：
1992-01-01
影响因子：
7.8
通讯作者：
GRIFFITHS, G
中科院分区：
文献类型：
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作者：
RABINOWITZ, S;HORSTMANN, H;GRIFFITHS, G
我们已经使用内吞和吞噬示踪剂在EM免疫细胞化学研究，以确定小鼠腹腔巨噬细胞的吞噬和内吞途径的车厢。内吞的BSA-金依次出现在早期内体、球形内体囊泡、晚期内体小管-网状隔室（TC）和终末溶酶体中。TC表现为富含溶酶体膜糖蛋白Lamp 1和Lamp 2的精细结构，并表达显著水平的rab 7，一种晚期内体特异性GTP结合蛋白。阳离子非依赖性甘露糖-6-磷酸受体被限制在TC的专门区域，这些区域主要与高尔基复合体相邻。早期的内体和TC都有包被的芽结构，其组成和功能目前尚不清楚。含有乳胶珠的吞噬溶酶体表达相同的膜抗原，并与TC同时接受内吞示踪剂。由于两个细胞器周围的膜也是直接连续的，我们假设这两个结构形成一个功能区室。巨唾液酸蛋白是一种局限于巨噬细胞和树突状细胞的抗原，在TC和吞噬溶酶体膜中大量表达，在其他内体隔室和细胞表面检测到低水平。用麦胚凝集素处理细胞显著改变了TC的形态，产生了紧密粘附的膜和大大扩展的囊泡，其中细胞相关的麦胚凝集素被浓缩。载有内化金示踪剂的球形内体载体囊泡聚集在附近，经常接触而不融合。由于内吞示踪剂向TC的递送被显著延迟，这些实验表明凝集素在某种程度上阻止了内体囊泡与TC融合。总的来说，我们的数据认为，PLC是相当于“管状溶酶体”通常描述的巨噬细胞，第二，会议的吞噬和内吞途径发生在这个隔间。
We have used endocytic and phagocytic tracers in an EM immunocytochemical study to define the compartments of the phagocytic and endocytic pathways in mouse peritoneal macrophages. Endocytosed BSA-gold appeared successively in early endosomes, spherical endosomal vesicles, a late endosomal tubulo-reticular compartment (TC), and terminal lysosomes. The TC appeared as an elaborate structure enriched for the lysosomal membrane glycoproteins Lamp 1 and Lamp 2, and expressing significant levels of rab7, a late endosome-specific GTP-binding protein. The cation-independent mannose-6-phosphate receptor was restricted to specialized regions of the TC that were predominantly adjacent to the Golgi complex. Both the early endosome and the TC had coated bud structures whose composition and function are presently unknown.Phagolysosomes containing latex beads expressed the same membrane antigens and received endocytic tracers simultaneously with the TC. Since the membrane surrounding both organelles was also in direct continuity, we assume that both structures form one functional compartment. Macrosialin, an antigen confined to macrophages and dendritic cells, was heavily expressed in TC and phagolysosomal membranes with low levels being detected in other endosomal compartments and on the cell surface. Treatment of cells with wheat germ agglutinin drastically altered the morphology of the TC, giving rise to sheets of tightly adherent membrane and greatly expanded vesicles, in which cell-associated wheat germ agglutinin was concentrated. The spherical endosomal carrier vesicles loaded with internalized gold tracers clustered nearby, often making contact without fusing. Since the delivery of endocytic tracer to the TC was significantly delayed these experiments suggest that the lectin is somehow preventing the endosome vesicles from fusing with the TC. Collectively, our data argue first that the PLC is equivalent to the "tubular lysosomes" commonly described in macrophages, and second that the meeting of the phagocytic and endocytic pathway occurs in this compartment.