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 x 10(4) islet cells (mean +/- SD) compared with 984 +/- 454 cpm/5 x 10(4) islet cells in islet cells incubated with plasma from nondiabetic BB rats (P less than 0.005). Twelve of the 14 diabetic rats with a duration of diabetes for 3-11 days bound radioactivity above the mean and 2 x SC 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 x 10(6) spleen lymphocytes compared with 3460 +/- 1809 in the controls (P less than 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.