The effects of pharmacologic agents on immune-complex-induced redistribution of B-lymphocyte Fc receptors

The effects of pharmacologic agents on the immune-complex-induced redistribution of B-lymphocyte Fc receptors (and, as a control, the anti-Ig induced redistribution of surface Ig) were examined. Immune-complex-induced capping of B-cell Fc receptors was moderately to markedly inhibited by the combination of colchicine and cytochalasin B, the Ca++ ionophore A23187, and the local anaesthetic lidocaine but was only slightly inhibited by cytochalasin B alone and was not inhibited by colchicine alone. Inhibition of capping was not due to the inhibition of binding of immune complexes to the B-lymphocytes or to decreased cell viability since these effects were absent. Preformed immune complex-Fc receptor caps were disrupted by A23187, lidocaine, and the combination of colchicine and cytochalasin B, but not by either colchicine or cytochalasin B alone. The effects of the pharmacologic agents were similar for Fc receptors and surface Ig in all cases. These results suggest that ligand bound Fc receptors are affected by cytoskeletal structures and that the ligand-induced redistribution of two distinct B lymphocyte surface receptors (fc receptors and surface Ig) occurs by similar or identical mechanisms.