Insulin Antibodies and Immune Insulitis in Rabbits Immunized with Bovine or Porcine Insulin Components

Abstract

90 rabbits were immunized with high (a and b) or low molecular weight (c) components of bovine or porcine insulin or with monocomponent (MC) porcine insulin for a period of four weeks in order to compare the immunogenicity of these components. Insulin antibody titres, expressed as insulin-binding capacity (I-BC) of the sera and frequency and intensity of immune insulitis of the pancreatic islets served as parameters for immunogenicity. The insulin preparations were injected four times either with Freund's adjuvant complete or predominantly with Freund's adjuvant incomplete.- Main results: the c-component of bovine insulin showed a stronger immunogenicity (I-BC: 3.87 ± 2.05 ng/ml; distinct insulitis: 60%) than the a-component (I-BC: 1.29 ± 0.42 ng/ml; insulitis: 0%). The c-component (I-BC: 1.38 ±1.27; slight insulitis: 40%) and the a-component (I-BC: 1.59 ± 1.15; insulitis: 0%) of porcine insulin exhibited a rather similar immunogenicity. The lowest immunogenicity (I-BC: 0.51 ± 0.62; insulitis: 0%) was associated with monocomponent (MC) porcine insulin. It is suggested that insulin-like contaminants of the c-component may play a more important role in insulin immunogenicity than is generally assumed.

Key words

Insulin Components - Monocomponent Insulin - Insulin Antibodies - Insulitis