Selective Immunotargeting of Pathogenic CD8 T Cells of Type 1 Diabetes Patients

Overview

It is well established that CD8 and CD4 T cells reactive against defined islet antigens are associated with initiation and progression of Type 1 Diabetes (T1D). In previous work, we have demonstrated that it is possible to redirect T cells against pathogenic T cells via chimeric peptide/MHC/CD3-zeta receptors in a peptide-specific manner and to prevent, or inhibit diabetes in NOD mice. In this study we intend to extend this approach to T cells of T1D patients. Working hypothesis: Beta cell-reactive CD8 T cells of human T1D patients can be immuno-targeted by their own gene-modified cytotoxic T lymphocytes (CTLs). Aims: Our major aim is to demonstrate, in a set of ex-vivo experiments, such immunotargeting with T cells derived from T1D patients at the Ziv Medical Center. To this end we will stimulate and expand autoreactive CD8 cells in blood samples of T1D patients and target them, ex-vivo, with genetically-reprogrammed CTLs which are present in the same blood samples.

To obtain proof-of-principle of our approach we have initiated tight collaboration between the Laboratory of Immunology at MIGAL Galilee Research Institute, Kiryat Shmona (MIGAL) and Breinin Center for Type 1 Diabetes and Endocrinology at the Ziv Medical Center in Safed (Ziv). In this study we will first identify carriers of the HLA-A0201 allele among pediatric and young adult T1D patients at Ziv. We will then screen the T cell pool in the peripheral blood samples of these patients for CD8 T cells reactive against any of 3 known HLA-A0201-binding peptides associated with autoreactivity in T1D: Insulin beta chain 10-18, IGRP 265-73 and IGRP 222-230. The influenza virus-derived peptide MP 58-66 will serve as reference. Next we will isolate polyclonal CD8 T cells from blood samples of the same patients, activate and expand them ex-vivo and transfect them via electroporation with in-vitro-transcribed mRNA encoding the respective peptide/MHC/CD3-zeta construct(s). We will then perform co-culture experiments assessing the ability of the mRNA-transfected T cells to kill the autoreactive T cells of the same patient in a peptide-selective manner.

Conditions