Proteolysis of band 3 is enhanced by anti-Rh sub(o)(D) binding to the red cell membrane

Surface radioiodinated human red cells were incubated with IgG fractions and the radioelectrophoretic profile of the ghost membranes determined. The patterns of RH sub(o)(D)-negative membranes exposed to anti-RH sub(o)(D) IgG and Rh sub(o)(D)-positive membranes exposed to non-immune IgG fractions remained intact. Membranes of RH sub(o)(D)-positive membranes following incubation with anti-Rh sub(o)(D) IgG showed a sharp reduction in the quantity of intact band 3, the main glycoprotein of the red cell membrane. This was significantly abrogated in the presence of protease inhibitors. The results suggest a possible role for IgG binding in promoting the generation of band 3-derived fragments described by others as normal constituents of isolated ghosts.