Adoptive Transfer of MRNA-Transfected T Cells Redirected Against Diabetogenic CD8 T Cells Can Prevent Diabetes

Chimeric major histocompatibility complex (MHC) molecules supplemented with T cell receptor (TCR) signaling motifs function as activation receptors and can redirect gene-modified T cells against pathogenic CD8 T cells. We have shown that β microglobulin (βm) operates as a universal signaling component of MHC-I molecules when fused with the CD3-ζ chain. Linking the H-2K-binding insulin B chain peptide insulin B chain, amino acids 15-23 (InsB) to the N terminus of βm/CD3-ζ, redirected polyclonal CD8 T cells against pathogenic CD8 T cells in a peptide-specific manner in the non-obese diabetic (NOD) mouse. Here, we describe mRNA electroporation for delivering peptide/βm/CD3-ζ genes to a reporter T cell line and purified primary mouse CD8 T cells. The peptide/βm/CD3-ζ products paired with endogenous MHC-I chains and transmitted strong activation signals upon MHC-I cross-linking. The reporter T cell line transfected with InsB/βm/CD3-ζ mRNA was activated by an InsB-H-2K-specific CD8 T cell hybrid only when the transfected T cells expressed H-2K. Primary NOD CD8 T cells expressing either InsB/βm/CD3-ζ or islet-specific glucose-6-phosphatase catalytic subunit-related protein, amino acids 206-214 (IGRP)/βm/CD3-ζ killed their respective autoreactive CD8 T cell targets in vitro. Furthermore, transfer of primary CD8 T cells transfected with InsB/βm/CD3-ζ mRNA significantly reduced insulitis and protected NOD mice from diabetes. Our results demonstrate that mRNA encoding chimeric MHC-I receptors can redirect effector CD8 against diabetogenic CD8 T cells, offering a new approach for the treatment of type 1 diabetes.