Clinical analysis of islet antigen eluted from type 1 diabetes-susceptible MHC molecule

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12671130
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Metabolomics
• Research Institution: Okinaka Memorial Institute for Medical Research
• Principal Investigator: NAKANISHI Koji Okinaka memorial institute for medical research, staff, 研究員 (80211423)
• Project Period (FY): 2000 – 2001
• Keywords: Type 1 diabetes / MHC molecule / antigenic peptide

Research Abstract

The aim of this study is to identify the peptide which derived from pancreatic islet and presented by type 1 diabetes-susceptible MHC class II molecule. B lymphobiastoid cell line was generated from peripheral blood of type 1 diabetic patient and cultured up to 10^<10> cells. After pulsing the debris of fetal islet cell line, HLA-DR and DQ molecule was recovered by affinity chromatography, treated by acid and subsequently applied to reverse phase HPLC. From the HPLC peaks specific for pulsing the debris of fetal islet cell line, I identified a peptide which consists of 14 amino acids. Homology search of this peptide identified Heparan sulfate/Heparin Interacting Protein as the native protein. The cDNA of this protein was cloned by RT-PCR from fetal islet cell line and the protein was expressed in E coil. Western blotting was performed using this bacterially expressed protein. However, the autoantigen against this protein was not detected by this westemblottig. The possible reasons of this are 1) T cell recognition of this peptide and production of autoantibody is far aparted events, 2) This peptide is T cell epitope exclusively for cell-mediated autoimmunity 3) Conformational epitope, not linear epitope, is recognized by autoantibody. Thus, the T cell response to this peptide or protein and immunoprecipitation for autoantibody detection will be needed in the future study.