Limited mobility of membrane receptors of adhered or proteose peptone-stimulated macrophages.

The mobility of the membrane receptors of macrophages, obtained from normal and proteose peptone-stimulated mice, was studied by counting the cells which form patches or caps after incubation with anti-H-2a antibody or soybean agglutinin (SBA). The test was carried out with macrophage suspension by the indirect fluorescence method. When macrophages from unstimulated donors were used, the antibodies against H-2a antigens bind at 4 degrees C to the surface of the macrophages in the form of small aggregates; only with SBA lectin a larger percentage of cells (20%) does form caps even at this low temperature. After heating the cells to 37 degrees C, a significant increase in the number of cells with receptors in caps was observed in the control mice. When macrophages from stimulated donors were used, no cap formation was observed with any of the ligands, even after a 120-minute-incubation; the ligand-receptor complexes form patches predominantly on the membrane. The pretreatment of macrophages with colchicine did not lead to a cap formation. A similar inhibition of the capping phenomenon also occurred with macrophages obtained from unstimulated mice, but tested in a monolayer.