Adoptive Transfer of mRNA-Transfected T Cells Redirected against Diabetogenic CD8 T Cells Can Prevent Diabetes

Abstract

Chimeric major histocompatibility complex (MHC) molecules supplemented with Tcell receptor (TCR) signaling motifs function as activation receptors and can redirect gene-modified Tcells against pathogenic CD8 Tcells. We have shown that β2 microglobulin (β2m) operates as a universal signaling component of MHC-I molecules when fused with the CD3-ζ chain. Linking the H-2Kd-binding insulin B chain peptide insulin B chain, amino acids 15-23 (InsB15-23) to the N terminus of β2m/CD3-ζ, redirected polyclonal CD8 Tcells against pathogenic CD8 Tcells in a peptide-specific manner in the non-obese diabetic (NOD) mouse. Here, we describe mRNA electroporation for delivering peptide/β2m/CD3-ζ genes to a reporter Tcell line and purified primary mouse CD8 Tcells. The peptide/β2m/CD3-ζ products paired with endogenous MHC-I chains and transmitted strong activation signals upon MHC-I cross-linking. The reporter Tcell line transfected with InsB15-23/β2m/CD3-ζ mRNA was activated by an InsB15-23-H-2Kd-specific CD8 Tcell hybrid only when the transfected Tcells expressed H-2Kd. Primary NOD CD8 Tcells expressing either InsB15-23/β2m/CD3-ζ or islet-specific glucose-6-phosphatasecatalytic subunit-related protein, amino acids 206-214 (IGRP206-214)/β2m/CD3-ζ killed their respective autoreactive CD8 Tcell targets invitro. Furthermore, transfer of primary CD8 Tcells transfected with InsB15-23/β2m/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 Tcells, offering a new approach for the treatment of type 1 diabetes.