Appearance of Fc receptors on polymorphonuclear leukocytes after migration and their role in phagocytosis

The effect of the migration of bovine blood polymorphonuclear leukocytes (PMNs) in vitro on their phagocytic activity was studied. PMNs were examined before and after migration through various membranes for rosette formation with sensitized sheep erythrocytes to detect Fc receptors (FcRs), phagocytic activity mediated through FcRs with opsonized staphylococci (Smith strain), and phagocytic activity mediated through nonimmunological receptors with unopsonized staphylococci (strain 305). Migration of PMNs was observed from the upper to the lower compartment of the blind well chamber through Millipore and Nuclepore membranes; through Millipore, Nuclepore, and nylon membranes coated with collagen; and through collagen-coated Millipore, Nuclepore, and nylon membranes overlaid with MA-104, BHK-21, MDBK-99, TB, or FBHE cells. Random migration of PMNs toward the plain medium (the same medium in the upper and lower compartments) through the membranes with and without a monolayer of cells increased the percentage of PMNs forming rosettes. In contrast, migration toward the medium containing lipopolysaccharide (LPS), formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), or zymosan-activated serum (Act. serum) did not change the percentage of PMNs forming rosettes. The increased percentage of PMNs forming rosettes was associated with the enhanced phagocytosis of opsonized staphylococci (mediated by FcRs). In contrast, migration of PMNs toward LPS, FMLP, or Act. serum did not enhance phagocytosis mediated through FcRs. However, PMNs after migration toward LPS, FMLP, Act. serum, and plain medium enhanced phagocytosis of unopsonized staphylococci (mediated through the nonimmunological receptors).