Screening of diabetes-associated autoantigens and serum antibody profiles by phage display system

Aims/Introduction: Phage display method is a crucial tool to find novel clinically valuable diabetes-associated autoantigens, and identify known autoantigen epitopes that are associated with diabetes; could providing scientific support and guidance for the artificial construction and synthesis of type I diabetes mellitus (T1DM) novel biomarkers. Materials and Methods: The phage display system was used for “bio-panning” of T1DM serum. Following by the sequencing of the phage DNAs, the homologous sequences of the above fusion heptapeptide were further investigated by BLAST to track the origin of the polypeptide sequences. The antibody spectrum revealed new T1DM-associated epitopes and antibodies. Results: A total of 1200 phage DNA were sequenced and 9 conserved polypeptide sequences were collected. It was confirmed that the zinc transporter and islet amyloid protease were among them.The conserved polypeptide sequence 8 and another three distinctive polypeptide sequences derived from Proteus were discovered. Furthermore, we expressed recombinant proteins with homologous polypeptide sequences for the human islet amyloid polypeptide (IAPP) polypeptide precursor human zinc transporter 8 (ZNT8). Through clinical sample detection for the serum from T1DM (n=100) and T2DM (n=200) patients, results demonstrate the importance and relevance of these polypeptides in the recognition and classification of various forms of diabetes. Conclusion：Human pancreatic and concurrent bacterial-derived protein antigens and their epitopes were identified in this research by phage display system, which is crucial for distinguishing different types of diabetes.