Block in Insulin Release from Column-Perifused Pancreatic β-Cells Induced by Islet Cell Surface Antibodies and Complement

Dispersed rat pancreatic islet cells were mixed into a short column of Bio-Gel P-2 polyacrylamide beads and perifused with an antiserum containing islet cell surface antibodies. The release of radioactive chromium from prelabeled cells, as a measure of cell membrane permeability, was not affected by cell surface antibodies alone, but increased dramatically in the presence of complement. While there was an eightfold increase in glucose-stimulated insulin release from β-cells exposed to control serum and complement, insulin release was completely blocked from β-cells exposed to islet-cell-specific antibodies and complement. These findings suggest that islet cell surface antibodies can mediate complement-dependent cytotOXicity.