Summary
The first human monoclonal islet cell antibodies of the IgG class (MICA 1-6) obtained from an individual with Type 1 (insulin-dependent) diabetes mellitus were cytoplasmic islet cell antibodies selected by the indirect immunofluorescence test on pancreas sections. Surprisingly, they all recognized the 64 kDa autoantigen glutamate decarboxylase. In this study we investigated which typical features of cytoplasmic islet cell antibodies are represented by these monoclonals. We show by double immunofluorescence testing that MICA 1-6 stain pancreatic beta cells which is in agreement with the beta-cell specific expression of glutamate decarboxylase. In contrast an islet-reactive IgM monoclonal antibody obtained from a pre-diabetic individual stained all islet cells but lacked the tissue specificity of MICA 1-6 and must therefore be considered as a polyreactive IgM-antibody. We further demonstrate that MICA 1-6 revealed typical features of epitope sensitivity to biochemical treatment of the target tissue which has been demonstrated for islet cell antibodies, and which has been used to argue for a lipid rather than a protein nature of target antigens. Our results provide direct evidence that the epitopes recognized by the MICA are destroyed by methanol/chloroform treatment but reveal a high stability to Pronase digestion compared to proinsulin epitopes. Conformational protein epitopes in glutamate decarboxylase therefore show a sensitivity to biochemical treatment of sections such as ganglioside epitopes. MICA 1-6 share typical features of islet cell and 64 kDa antibodies and reveal that glutamate decarboxylase-reactive islet cell antibodies represent a subgroup of islet cell antibodies present in islet cell antibody-positive sera.
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Bottazzo GF, Florin-Christensen A, Doniach D (1974) Islet cell antibodies in diabetes mellitus with autoimmune polyendocrine deficiencies. Lancet II: 1279–1283
Bottazzo GF, Doniach D (1978) Islet-cell antibodies (ICA) in diabetes mellitus. Evidence of an autoantigen common to all cells in the islet of Langerhans. La Ricerca Clin Lab 8: 29–38
Baekkeskov S, Nielsen JH, Marner B, Bilde T, Ludvigsson J, Lernmark Å (1982) Autoantibodies in newly diagnosed diabetic children immunoprecipitate pancreatic islet cell proteins. Nature 298: 167–169
Baekkeskov S, Aanstoot HJ, Christgau S et al. (1990) Identification of the 64K autoantigen in insulin-dependent diabetes as the GABA-synthesizing enzyme glutamic acid decarboxylase. Nature 347: 151–156
Nayak RC, Omar AK, Rabizadeh A, Srikanta S, Eisenbarth GS (1985) Cytoplasmic islet cell antibodies: evidence that the target antigen is a sialoglycoconjugate. Diabetes 34: 617–619
Colman PG, Nayak RC, Campbell IL, Eisenbarth GS (1988) Binding of cytoplasmic islet cell antibodies is blocked by human pancreatic glycolipid extracts. Diabetes 37: 645–652
Richter W, Endl J, Eiermann TH et al. (1992) Human monoclonal islet cell antibodies from a patient with insulin-dependent diabetes mellitus reveal glutamate decarboxylase as the cytoplasmic islet cell antigen. Proc Natl Acad Sci USA 89: 8467–8471
Richter W, Shi Y, Baekkeskov S (1993) Autoreactive epitopes defined by diabetes associated human monoclonal antibodies. Proc Natl Acad Sci USA: 90: 2832–2836
Richter W, Eiermann TH, Graf G, Glueck M, Scherbaum WA, Pfeiffer EF (1989) Isolation of IgG islet cell antibody-producing B-lymphocytes from the peripheral blood of type I diabetic patients and an ICA-positive nondiabetic individual. Horm Metabol Res 21: 686–688
Scherbaum WA, Mirakian R, Pujol-Borrell R, Dean BM, Bottazzo GF (1986) Immunocytochemistry in the study and diagnosis of organ-specific autoimmune diseases. In: Polak M, Van Noorden S (eds) Immunocytochemistry modern methods and applications. Wright, Bristol, pp 456–476
Tuson RJ, Pascoe EW, Jacob DA (1990) A novel immunohistochemical technique for demonstration of specific binding of human monoclonal antibodies to human cryostat tissue sections. J Histochem Cytochem 38: 923–926
Eisenbarth GS, Shimizu K, Bowring MA, Wells S (1982) Expression of receptors for tetanus toxin and monoclonal antibody A2B5 by pancreatic islet cells. Proc Natl Acad Sci USA 79: 5066–5070
Satoh J, Prabhakar BS, Haspel MV, Ginsberg-Fellner F, Notkins AL (1983) Human monoclonal autoantibodies that react with multiple endocrine organs. New Engl J Med 309: 217–220
Casali P, Notkins AL (1990) Probing the human B-cell repertoire with EBV: polyreactive antibodies and CD5 + B lymphocytes. Ann Rev Immunol 7: 513–535
Christie MR, Pipeleers DG, Lernmark A, Baekkeskov S (1990) Cellular and subcellular localization of an Mr 64.000protein autoantigen in insulin-dependent diabetes. J Biol Chem 265: 376–381
Garry DJ, Sorenson RL, Elde RP, Maley BE, Madsen A (1986) Immunohistochemical colocalization of GABA and insulin in β-cells of rat islets. Diabetes 35: 1090–1095
Sorenson RL, Garry DG, Brelje TC (1991) Structural and functional considerations of GABA in islets of Langerhans. Diabetes 40: 1365–1374
Atkinson MA, MacLaren NK, Scharp DW, Lacy PE, Riley WJ (1990) 64.000 Mr autoantibodies as predictors of insulin-dependent diabetes. Lancet 335: 1357–1360
Gianani R, Pugliese A, Bonner-Weir S et al. (1992) Prognostically significant heterogeneity of cytoplasmic islet cell antibodies in relatives of patients with type 1 diabetes. Diabetes 41: 347–353
Genovese S, Bonifacio E, McNally JM (1992) Distinct cytoplasmic islet cell antibodies with different risks for type 1 (insulin-dependent) diabetes mellitus. Diabetologia 35: 385–388
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Richter, W., Eiermann, T.H., Endl, J. et al. Human monoclonal islet specific autoantibodies share features of islet cell and 64 kDa antibodies. Diabetologia 36, 785–790 (1993). https://doi.org/10.1007/BF00401152
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DOI: https://doi.org/10.1007/BF00401152