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 beta 2 microglobulin (beta(2)m) operates as a universal signaling component of MHC-I molecules when fused with the CD3-iota chain. Linking the H-2K(d)-binding insulin B chain peptide insulin B chain, amino acids 15-23 (InsB(15-23)) to the N terminus of beta(2)m/ CD3-zeta, 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/ b2m/ CD3-zeta genes to a reporter T cell line and purified primary mouse CD8 T cells. The peptide/ b2m/ CD3-z 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(15)-23/beta(2)m/ CD3-zeta mRNA was activated by an InsB(15-23) H-2K(d)-specific CD8 T cell hybrid only when the transfected T cells expressed H-2Kd. Primary NOD CD8 T cells expressing either InsB15-23/ b2m/ CD3-zeta or islet-specific glucose-6phosphatase catalytic subunit-related protein, amino acids 206-214 (IGRP(206-214))/ beta(2)m/ CD3-zeta killed their respective autoreactive CD8 T cell targets in vitro. Furthermore, transfer of primary CD8 T cells transfected with InsB(15-23)/ beta(2)m/ CD3 zeta 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.