Islet-Specific CTL Cloned from a Type 1 Diabetes Patient Cause Beta-Cell Destruction after Engraftment into HLA-A2 Transgenic NOD/SCID/IL2RG Null Mice

Wendy W J Unger,Sandra Laban,Bart O Roep,Todd Pearson,Joana R F Abreu,Leonard D Shultz,Arno R Van Der Slik,Dave V Serreze,Michel G D Kester,Jan Wouter Drijfhout,Marieke Griffioen,Sacha Mulder-Van Der Kracht,Dale L Greiner

doi:10.1371/journal.pone.0049213

Abstract

Despite increasing evidence that autoreactive CD8 T-cells are involved in both the initiation of type 1 diabetes (T1D) and the destruction of beta-cells, direct evidence for their destructive role in-vivo is lacking. To address a destructive role for autoreactive CD8 T-cells in human disease, we assessed the pathogenicity of a CD8 T-cell clone derived from a T1D donor and specific for an HLA-A2-restricted epitope of islet-specific glucose-6-phosphatase catalytic-subunit related protein (IGRP). HLA-A2/IGRP tetramer staining revealed a higher frequency of IGRP-specific CD8 T-cells in the peripheral blood of recent onset human individuals than of healthy donors. IGRP265–273-specific CD8 T-cells that were cloned from the peripheral blood of a recent onset T1D individual were shown to secrete IFNγ and Granzyme B after antigen-specific activation and lyse HLA-A2-expressing murine islets in-vitro. Lytic capacity was also demonstrated in-vivo by specific killing of peptide-pulsed target cells. Using the HLA-A2 NOD-scid IL2rγnull mouse model, HLA-A2-restricted IGRP-specific CD8 T-cells induced a destructive insulitis. Together, this is the first evidence that human HLA-restricted autoreactive CD8 T-cells target HLA-expressing beta-cells in-vivo, demonstrating the translational value of humanized mice to study mechanisms of disease and therapeutic intervention strategies.

Highlights

Non-obese diabetic (NOD) mice are widely used for studying the pathogenesis and therapy of autoimmune type 1 diabetes (T1D) [1]
IGRP265–273 has been identified as an epitope of islet autoreactive CD8 T cells using NOD-b2mtm1Unc HHD Tg mice that express a chimeric HLA-A2.1/H-2Db molecule [16]
Using A2/islet-specific glucose-6-phosphatase catalytic-subunit related protein (IGRP) tetramers and CD8 antibodies, IGRP-specific CD8 T-cells were identified in Peripheral blood mononuclear cells (PBMCs) of HLA-A2+ recent onset individuals but not of healthy controls, confirming previous findings (Figure 1A)

Summary

Introduction

Non-obese diabetic (NOD) mice are widely used for studying the pathogenesis and therapy of autoimmune type 1 diabetes (T1D) [1]. Autoreactive CD4 and CD8 T-cells in NOD mice infiltrate and subsequently destroy the insulin-producing beta-cells in pancreatic islets, resulting in dysregulation of blood glucose levels and hyperglycemia [2;3]. Studies using NOD mice have helped to define mechanisms of disease pathogenesis and to identify potential interventional and therapeutic strategies in autoimmune diabetes, there are discrepancies between disease pathogenesis in NOD mice and in humans. Transgenic expression of HLA-A2 significantly accelerates disease onset in NOD mice, and is associated with the early appearance of HLA-A2-restricted CD8+ T-cells in prediabetic insulitic lesions [13]

Methods

Results

Conclusion