Internalization and rapid recycling of macrophage Fc receptors tagged with monovalent antireceptor antibody: possible role of a prelysosomal compartment.
Internalization and rapid recycling of macrophage Fc receptors tagged with monovalent antireceptor antibody: possible role of a prelysosomal compartment.
复制标题
巨噬细胞FC受体的内在化和快速回收，用单价抗受体抗体标记：prysosomal室的可能作用。
DOI：
10.1083/jcb.98.4.1163
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发表时间：
1984-04
期刊：
影响因子：
--
通讯作者：
Ukkonen P
中科院分区：
文献类型：
--
作者：
Mellman I;Plutner H;Ukkonen P
小鼠巨噬细胞对含多价IgG的免疫复合物的结合和胞饮导致Fc受体（FcR）从细胞表面的选择性去除，并导致受体和配体快速递送至溶酶体，在溶酶体中两者都被降解（I. Mellman和H. Plutner，1984，Journal of Cell Biology，98：1170-1177）。在本文中，我们研究了与单价探针，不像IgG复合物，不能交联相邻的受体标记的FcR的内化。我们使用了高亲和力抗FcR单克隆抗体的Fab片段，其结合对4 ℃下的低pH（4.0）完全敏感。因此，表面结合（酸可释放）和细胞内（耐酸）125 I-Fab可以很容易地区分。J774巨噬细胞与125 I-Fab在37 ℃下孵育不会导致大量抗体在耐酸隔室中积累。3小时后，只有20%的总细胞相关的放射性标记是细胞内的。Percoll梯度离心也显示内化的125 I-Fab主要与低密度内体相关，而不是与溶酶体相关。值得注意的是，大多数标记的抗体迅速返回到质膜，仍然与FcR结合。这种回收是在10分钟内完成，不受NH 4Cl，只有轻微的抑制Na+-H+离子载体莫能菌素。这些结果表明单价Fab-FcR复合物被内化，递送至内体，并迅速返回至细胞表面。由于多价IgG复合物的内化将FcR从该回收途径中去除并导致其转运至溶酶体，因此我们认为内体膜中的受体聚集状态有助于确定其细胞内命运。
Binding and pinocytosis of polyvalent IgG-containing immune complexes by mouse macrophages leads to the selective removal of Fc receptors (FcR) from the cell surface and to the rapid delivery of receptor and ligand to lysosomes, where both are degraded (I. Mellman and H. Plutner, 1984, Journal of Cell Biology, 98:1170-1177). In this paper, we have studied the internalization of FcR tagged with a monovalent probe that, unlike IgG-complexes, cannot cross-link adjacent receptors. We have used an Fab fragment of high affinity anti-FcR monoclonal antibody whose binding was completely sensitive to low pH (4.0) at 4 degrees C. Thus, surface-bound (acid-releasable) and intracellular (acid-resistant) 125I-Fab could be readily distinguished. Incubation of J774 macrophages with 125I-Fab at 37 degrees C did not lead to the accumulation of large amounts of the antibody in the acid-resistant compartment. After 3 h, only 20% of the total cell-associated radiolabel was intracellular. The internalized 125I-Fab was also shown by Percoll gradient centrifugation to be associated primarily with low density endosomes, as opposed to lysosomes. Significantly, most of the labeled antibody returned rapidly to the plasma membrane, still bound to FcR. This recycling was complete within 10 min, was unaffected by NH4Cl, and was only slightly inhibited by the Na+-H+ ionophore monensin. These results indicate that monovalent Fab-FcR complexes are internalized, delivered to endosomes, and rapidly returned to the cell surface. Since the internalization of polyvalent IgG-complexes removed the FcR from this recycling pathway and caused its transport to lysosomes, we suggest that the state of receptor aggregation in the endosome membrane helps determine its intracellular fate.