Autoantibodies to glutamate decarboxylase detected in diabetes-prone BB/OK rats do not distinguish onset of diabetes.
The diabetes syndrome of the BB rat resembles human Type 1 (insulin-dependent) diabetes including the prevalence of autoantibodies to the 64 kDa Beta-cell autoantigen, which has been identified as glutamate decarboxylase. This study aimed at detecting the prevalence and level of glutamate decarboxylase autoantibodies in 120-day-old diabetic and non-diabetic diabetes-prone BB/OK rats compared to those of sex- and age-matched diabetes-resistant LEW.1A rats. The antibodies were detected using semipurified glutamate decarboxylase from rat brain in two immunoassays, a direct and a sandwich enzyme-linked immunosorbent assay. For the last assay autoantibody-containing immunoglobulins of a serum from a patient with the stiff-man syndrome were used to bind specifically the enzyme as autoantigen in plastic wells. The antibody levels measured as optical density at 490 nm (x +/- SD)/prevalence of the diabetic group (120 +/- 29 days of age) of BB/OK rats 0.57 +/- 0.29 (n = 51)/88% as well as those of the nondiabetic group (121 +/- 26 days of age) with 0.51 +/- 0.29 (n = 32)/97% was significantly increased (p < 0.01) compared to those of the diabetes-resistant control group 0.15 +/- 0.06 (n = 29)/0%. Furthermore in a 209 +/- 27-day-old group (n = 21) of non-diabetic but diabetes-prone BB/OK rats the autoantibody levels of 1.21 +/- 0.39 vs 0.51 +/- 0.26 were further significantly enhanced (p < 0.01). These results were confirmed by a sandwich assay.(ABSTRACT TRUNCATED AT 250 WORDS)
Ziegler
M
M
Department of Immunochemistry, Institute of Diabetes, Gerhardt Katsch, Karlsburg, Medical Faculty, Ernst-Moritz-Arndt University of Greifswald, Germany.
Schlosser
M
M
Hamann
J
J
Vieregge
P
P
Lühder
F
F
Klöting
I
I
Ziegler
B
B
D017668:Age of Onset; D000818:Animals; D001323:Autoantibodies / Q000032:analysis*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics* / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D008297:Male; D051381:Rats; D011910:Rats, Brattleboro; D011917:Rats, Inbred Lew
D001323:Autoantibodies; D005968:Glutamate Decarboxylase