caa a22 4500 475772040 CHVBK 20180406123620.0 cr unu---uuuuu 170329e20001001xx s 000 0 eng 10.1007/s001250051525 doi (NATIONALLICENCE)springer-10.1007/s001250051525 Humoral autoreactivity to an alternatively spliced variant of ICA512/IA-2 in Type I diabetes [Elektronische Daten] [Y. S. Park, E. Kawasaki, K. Kelemen, L. Yu, M. R. Schiller, M. Rewers, M. Mizuta, G. S. Eisenbarth, J. C. Hutton] Aims/hypothesis. The receptor tyrosine phosphatase like-protein ICA512/IA-2 occurs as a proteolytically-processed 65,000 Mr type 1 transmembrane glycoprotein in beta cells and is a major autoantigen of Type I (insulin-dependent) diabetes mellitus. We investigated whether alternative splicing could affect humoral autoreactivity to the molecule.¶Methods. Genomic and cDNA sequence analysis showed the presence of a ICA512 variant in islets and lymphoid tissues with an in-frame deletion of exon 13 which produces a secreted form lacking aa 557-629 including the transmembrane domain (aa 577 to 600). The alternatively spliced protein is detectable by western blotting in normal islets and translated into a protein that is processed to a series of soluble forms of 25,000-35,000 Mr. Radioimmunoprecipitation assays for anti-ICA512 autoantibodies were developed with the widely used ICA512.bdc construct (which has exon 13 deleted) and a series of full-length and modified ICA512/IA-2 molecules. ¶Results. The assays showed that ICA512.bdc and ICA512604-979 gave the best discrimination between diabetic and control sera. With ICA512604-979 a somewhat greater proportion of patients expressing antibodies were detected than with ICA512.bdc in the groups studied (70.5 % vs 63.2 % of prediabetic/new-onset and 25.0 vs 13.9 % in patients with diabetes > 20 years). Conversely, a small proportion (3 % recent-onset and 6 % > 20 years) had antibodies to ICA512.bdc but not ICA512604-979.¶Conclusion/interpretation. Important epitopes lie within the exon 13 region and others can be generated by the alternative splicing. As the Δexon 13 variant is probably secreted by the beta cell, it could be recognized by the cellular and humoral arm of the immune system in the absence of cellular damage. [Diabetologia (2000) 43: 1293-1301] Springer-Verlag Berlin Heidelberg, 2000 Keywords Insulin-dependent diabetes mellitus, alternative splicing variant, ICA512/IA-2 nationallicence Park Y. S. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut Kawasaki E. The First Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan, JP aut Kelemen K. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut Yu L. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut Schiller M. R. Department of Pathology and Anesthesiology/Critical Care Medicine, Johns Hopkins University, Baltimore, USA, US aut Rewers M. Department of Preventive Medicine and Biometrics, University of Colorado, School of Medicine, Denver, USA, US aut Mizuta M. The Third Department of Internal Medicine, Miyazaki Medical College, Miyazaki, Japan, JP aut Eisenbarth G. S. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut Hutton J. C. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut https://doi.org/10.1007/s001250051525 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s001250051525 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Park Y. S. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut NATIONALLICENCE 700 1- Kawasaki E. The First Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan, JP aut NATIONALLICENCE 700 1- Kelemen K. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut NATIONALLICENCE 700 1- Yu L. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut NATIONALLICENCE 700 1- Schiller M. R. Department of Pathology and Anesthesiology/Critical Care Medicine, Johns Hopkins University, Baltimore, USA, US aut NATIONALLICENCE 700 1- Rewers M. Department of Preventive Medicine and Biometrics, University of Colorado, School of Medicine, Denver, USA, US aut NATIONALLICENCE 700 1- Mizuta M. The Third Department of Internal Medicine, Miyazaki Medical College, Miyazaki, Japan, JP aut NATIONALLICENCE 700 1- Eisenbarth G. S. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut NATIONALLICENCE 700 1- Hutton J. C. Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, USA, US aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer