Two hypotheses were tested: first, that in LEW rats the interaction of sheep (or rabbit) anti-brush border antibodies with antigens (Heymann antigens) expressed on the plasma membrane of glomerular visceral epithelial cells is characterized by initial redistribution of immune complexes on the cell surface and by subsequent shedding of immune complexes in the subepithelial part of the capillary wall; and secondly, that this interaction is inhibited by chlorpromazine, a drug that displaces calcium ions from binding sites linking the plasma membrane to the cytoskeleton, and which blocks the redistribution of IgG on the surface of B lymphocytes exposed to anti-IgG antibodies. The studies were performed in vitro on cultured LEW glomerular epithelial cells and in vivo in LEW rats. In cultured glomerular epithelial cells exposed at 37 degrees C to anti-brush border IgG, chlorpromazine prevented, in a dose-dependent manner, the redistribution ("capping") of Heymann antigens and the fixation of complement. The renal glomeruli of chlorpromazine-treated LEW rats examined 6 and 48 hr after transfer of anti-brush border antibodies had punctate and, later, punctate and diffuse deposits of sheep (or rabbit) IgG on glomerular epithelial cells, but not similar deposits of rat C3. Moreover, granular subepithelial deposits of sheep (or rabbit) IgG and rat C3, characteristic of passive Heymann glomerulonephritis, did not develop, although deposits of sheep IgG were detected by immunoelectron microscopy on the microvilli of glomerular epithelial cells. Comparative studies on rats with similar reductions in glomerular filtration rates, produced by high doses of chlorpromazine or with renal artery stenosis, showed that the findings were not the consequence of insufficient delivery of antibody to glomerular epithelial cells. The results are consistent with the interpretation that Heymann glomerulonephritis is induced by mechanisms of redistribution of cell surface antigens comparable to those that govern the interaction of surface antigens (or receptors) with appropriate ligands in B lymphocytes and other classical in vitro systems.