Autoantibodies against the insulin receptor recognize the insulin binding subunits of an oligomeric receptor.

Abstract

125I-insulin was specifically cross-linked to membranes of human cultured lymphocytes (IM-9 line) using disuccinimidyl suberate. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions and autoradiography of this preparation revealed a major 125I-labeled band with an apparent mol wt of 130,000 and minor bands of about 300,000 and 95,000. Labeling of these bands was inhibited by incubation of membranes with either unlabeled insulin or autoantibodies to the insulin receptor. The bands were also observed after the 125I-insulin cross-linked preparation was solubilized and immunoprecipitated with a panel of autoantibodies to the insulin receptor. However, immunoprecipi..