Griffin F M, Mullinax P J
J Exp Med. 1981 Aug 1;154(2):291-305. doi: 10.1084/jem.154.2.291.
We have previously reported that treatment with a unique lymphokine enables resident mouse peritoneal macrophages to phagocytize via their complement receptors and we have presented evidence that the lymphokine act by enabling complement receptor engagement by C3b ligands to generate a phagocytic signal, thereby linking the cell surface binding event with the intracellular phagocytic machinery. In the present experiments, we used immobilized immune complexes to study the topography of C3b receptors of resident mouse peritoneal macrophages treated with the lymphokine. Our results indicate that lymphokine treatment enables the macrophages' C3b receptors to migrate within the plane of the cells' plasma membrane and that manipulations of macrophages that abrogate one response to the lymphokine, complement receptor mobility, also abrogate the other response, complement receptor-mediated phagocytosis. These findings strongly suggest that lateral mobility of a ligand-bound receptor within the macrophage plasma membrane is an essential component of the phagocytic signal. Moreover, our results indicate that the difference in complement receptor function among various populations of macrophages is not due to the expression of different types of complement receptors by the different macrophage populations but rather to a difference in the relationship of the C3b receptor with other plasma membrane or intracellular components.
我们之前曾报道，用一种独特的淋巴因子进行处理，可使小鼠腹膜常驻巨噬细胞通过其补体受体进行吞噬作用，并且我们已提出证据表明，该淋巴因子的作用是使补体受体与C3b配体结合，从而产生吞噬信号，进而将细胞表面结合事件与细胞内吞噬机制联系起来。在本实验中，我们使用固定化免疫复合物来研究经淋巴因子处理的小鼠腹膜常驻巨噬细胞的C3b受体的拓扑结构。我们的结果表明，淋巴因子处理可使巨噬细胞的C3b受体在细胞质膜平面内迁移，并且对巨噬细胞的操作若消除了对淋巴因子的一种反应（补体受体的流动性），也会消除另一种反应（补体受体介导的吞噬作用）。这些发现有力地表明，配体结合受体在巨噬细胞质膜内的侧向流动性是吞噬信号的一个重要组成部分。此外，我们的结果表明，不同巨噬细胞群体之间补体受体功能的差异并非由于不同巨噬细胞群体表达不同类型的补体受体，而是由于C3b受体与其他质膜或细胞内成分之间关系的差异。
