Islet Cell Surface Antibodies and Lymphocyte Antibodies in the Spontaneously Diabetic BB Wistar Rat

Plasma from 14 diabetic and 6 nondiabetic BB Wistar rats along with plasma from 6 non-BB Wistar rats was evaluated for the presence of islet cells surface antibodies (ICSA) and antibodies to spleen lymphocytes by the protein-A radioligand assay. Dispersed Wistar rat islet cells incubated with plasma from diabetic rats bound 4255 ± 2208 cpm ¹²⁵I-protein A/5 × 10⁴ islet cells (mean ± SD) compared with 984 ± 454 cpm/5 × 10⁴ islet cells in islet cells incubated with plasma from nondiabetic BB rats (P < 0.005). Twelve of the 14 diabetic rats with a duration of diabetes for 3–11 days bound radioactivity above the mean and 2 × SD of controls. The binding of ¹²⁵I-protein A did not differ between nondiabetic BB rats and non-BB Wistar rats. Wistar rat spleen lymphocytes incubated in diabetic plasma bound 20,249 ± 10,783 cpm/2 × 10⁶ spleen lymphocytes compared with 3460 ± 1809 in the controls (P < 0.005). Animals positive for ICSA correlated with those positive for spleen lymphocyte antibodies. It is concluded that ICSA and splenic lymphocyte antibodies are present in diabetic BB rats.