Untersuchungen zur Lokalisation der Insertionsstellen Insulinbindender Antikörper am Insulinmolekül

Summary Using preparative ultracentrifugation it can be demonstrated that in anti-insulin sera from diabetics treated with heterologous insulin, S-sulfonated B chains prepared from ox insulin inhibited the binding of bovine insulin-131 I by specific antibodies, whereas S-sulfonated A chains had no effect. Intact bovine insulin showed the greatest competitive activity. In anti-insulin sera from two sheep and a pig immunized against the homologous sheep and pig insulin the following results were obtained: SS-A chains showed a very small effect, SS-B chains a stronger one and the homologous sheep and pig insulin the strongest displacement of sheep and pig insulin-131 I from antibody binding. In anti-insulin sera from guinea-pigs immunized against ox insulin only SS-B chains and not SS-A chains were able to displace ox insulin-131I from antibody binding to a significant degree. On the other hand, anaphylactic antibodies stimulated by ox insulin and detected by the Schultz-Dale reaction combined with both SS-A chains and SS-B chains.