Anti-idiotype guinea pig antibodies as response to insulin immunization

Abstract

The study was done using 39 guinea pigs grouped as followed; 18 were injected with 0.5 mg of porcine insulin emulsified in complete Freund's adjuvant; 12 were injected with saline and 9 were used as control of cardiac bleeding during the assay. Intraperitoneal glucose tolerance tests (IGTT) were carried out on days 0, 11, 32 and 38. Seven of the thirteen guinea pigs immunized with insulin which survived after the study, showed glucose intolerance on day 32 at 90 and 120 min (p < 0.01 and p < 0.001) and on day 38 at 120 min (p < 0.05). Anti-idiotypic IgG partially purified from a sera pool from these animals inhibited 125-Insulin binding to rat hepatocytes, immunoprecipitated 125I-rat insulin receptors and recognized the alpha-subunit of insulin receptor in immunoblotting. We conclude that insulin anti-idiotypes in guinea pigs offer a simple way to produce antibodies against insulin receptor binding site. The methodology for anti-idiotype identification can be applied to patients with insulin resistance.