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Immunodiabetes in rabbits
M Titlbach1, K Nouza, M Müllerová
1Institute of Experimental Medicine, Czechoslovak Academy of Sciences, Praha.
Summary
Immunizing rabbits with insulin and its components altered blood sugar levels and antibody production. Histological changes in pancreatic islets suggest both damage and repair processes occur after insulin immunization.
Area of Science:
- Immunology
- Endocrinology
- Histopathology
Background:
- Insulin immunization in animal models is crucial for understanding autoimmune diabetes.
- Investigating the effects of different insulin preparations and adjuvants on immune response and pancreatic function is necessary.
Purpose of the Study:
- To investigate the effects of crystalline insulin (CI), chromatographically purified insulin (CPI), and waste products (WP) on glycemia, glucose/insulin tolerance, and antibody production in rabbits.
- To evaluate the role of complete Freund's adjuvant (CFA) in modulating the immune response to insulin antigens.
- To examine the morphological changes in pancreatic islets of Langerhans following immunization.
Main Methods:
- Rabbits were immunized with CI, CPI, and WP, with and without CFA.
- Basal glycemia, glucose tolerance tests, and insulin tolerance tests were performed.
- Hemagglutinating antibody titers were measured.
- Histological and ultrastructural examinations of pancreatic islets were conducted.
Main Results:
- Immunization with CI and its components altered glycemia and glucose/insulin tolerance tests.
- Peak antibody levels were observed after WP immunization; lowest levels followed CPI immunization.
- Complete Freund's adjuvant (CFA) generally enhanced antibody production.
- No correlation was found between antibody titers and glycemia.
- Pancreatic B-cells showed degranulation and A-cells exhibited hyperplasia; insulitis was observed in groups receiving CI or CPI with CFA.
- Ultrastructural analysis revealed B-cells with granules similar to fetal cells in rabbits immunized with CI and CFA.
Conclusions:
- Insulin immunization in rabbits induces significant changes in glucose metabolism and antibody production.
- The immune response and pancreatic morphology are influenced by the type of insulin antigen and the presence of CFA.
- Evidence suggests that initial islet damage may be followed by reparative processes, including B-cell mitosis and A-cell hyperplasia.