Islet Amyloid Polypeptide Is a Target Antigen for Diabetogenic CD4+ T Cells

• DOI: 10.2337/db11-0288
• Publication Date: 2011-07-07T04:19:21Z
• Authors: Thomas Delong; Rocky L. Baker; Nichole Reisdorph; Richard Reisdorph; Roger L. Powell; Michael Armstrong; Gene Barbour; Brenda Bradley; Kathryn Haskins
• Keywords: CD4-Positive T-Lymphocytes; Antigen-Presenting Cells; Autoantigens; Mass Spectrometry; Islet Amyloid Polypeptide; Islets of Langerhans; Mice; 03 medical and health sciences; Diabetes Mellitus, Type 1; 0302 clinical medicine; Mice, Inbred NOD; Animals; Immunology and Transplantation

OBJECTIVE To investigate autoantigens in β-cells, we have used a panel of pathogenic T-cell clones that were derived from the NOD mouse. Our particular focus in this study was on the identification of the target antigen for the highly diabetogenic T-cell clone BDC-5.2.9.

RESEARCH DESIGN AND METHODS To purify β-cell antigens, we applied sequential size exclusion chromatography and reverse-phase high-performance liquid chromatography to membrane preparations of β-cell tumors. The presence of antigen was monitored by measuring the interferon-γ production of BDC-5.2.9 in response to chromatographic fractions in the presence of NOD antigen-presenting cells. Peak antigenic fractions were analyzed by ion-trap mass spectrometry, and candidate proteins were further investigated through peptide analysis and, where possible, testing of islet tissue from gene knockout mice.

RESULTS Mass-spectrometric analysis revealed the presence of islet amyloid polypeptide (IAPP) in antigen-containing fractions. Confirmation of IAPP as the antigen target was demonstrated by the inability of islets from IAPP-deficient mice to stimulate BDC-5.2.9 in vitro and in vivo and by the existence of an IAPP-derived peptide that strongly stimulates BCD-5.2.9.

CONCLUSIONS IAPP is the target antigen for the diabetogenic CD4 T-cell clone BDC-5.2.9.