We incubated mouse peritoneal macrophages for 3-8 min at 37 degrees C with antibody-coated sheep erythrocytes and examined regions of close interaction between the two cell types by electron microscopy. At sites of focal macrophage-erythrocyte contact we observed a distinctive specialization of the macrophage plasma membrane consisting of a prominent subplasmalemmal band of electron-dense material, approximately 25-35 nm in thickness. In many instances, this band showed a periodic substructure similar to that seen in clathrin coats. Moreover, many slender erythrocyte processes penetrated into invaginations of the macrophage surface which were bristle-coated at their blind extremity. As previously shown for clathrin-coated pits, the segments of the macrophage plasma membrane beneath which the defense material was found were selectively resistant to the membrane-perturbing effect of the antibiotic, filipin. This structural specialization of the macrophage plasma membrane at sites of ligand-receptor interaction during immune phagocytosis of antibody-coated erythrocytes may represent the morphological counterpart of the zipper mechanism of phagocytosis previously demonstrated by functional studies.
Specialization of the macrophage plasma membrane at sites of interaction with opsonized erythrocytes.
R Montesano, A Mossaz, P Vassalli, L Orci; Specialization of the macrophage plasma membrane at sites of interaction with opsonized erythrocytes.. J Cell Biol 1 May 1983; 96 (5): 1227–1233. doi: https://doi.org/10.1083/jcb.96.5.1227
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