Islet cell surface antibodies in spontaneously diabetic BB rats

Area of Science:

• Immunology
• Endocrinology
• Diabetology

Background:

• Antibodies targeting normal Wistar rat islet cells are frequently observed in newly diagnosed diabetic BB rats.
• The presence and significance of these islet cell surface antibodies (ICSA) in the pathogenesis of diabetes require further investigation.

Purpose of the Study:

• To determine if antibodies found in BB rats bind to a cloned rat insulinoma cell line (RIN 5F).
• To investigate the prevalence of islet cell surface antibodies in offspring of diabetic BB rats and correlate with diabetes onset.

Main Methods:

• Utilized a protein A-radioligand assay to detect islet cell surface antibodies.
• Assessed antibody binding to both normal islet cells and the RIN 5F insulinoma cell line.
• Monitored antibody levels and diabetes incidence in offspring of diabetic BB rats.

Main Results:

• A strong correlation was observed between antibody binding to normal islet cells and the RIN 5F cell line.
• 85% of offspring from diabetic, antibody-positive parents developed diabetes, with a mean onset age of 88 days.
• 95% of young offspring (at 44 days) were positive for islet cell surface antibodies before diabetes diagnosis; antibody levels did not differ between diabetic and non-diabetic rats.

Conclusions:

• BB rats exhibit circulating antibodies that react with surface determinants on the RIN-5F insulin-producing cell line.
• A high prevalence of islet cell surface antibodies exists in young, unaffected BB rats, suggesting their potential role as an early marker for diabetes.