RNAi-mediated TCR knockdown prevents autoimmunity in mice caused by mixed TCR dimers following TCR gene transfer

Item Type:	Article
Title:	RNAi-mediated TCR knockdown prevents autoimmunity in mice caused by mixed TCR dimers following TCR gene transfer
Creators Name:	Bunse, M. and Bendle, G.M. and Linnemann, C. and Bies, L. and Schulz, S. and Schumacher, T.N. and Uckert, W.
Abstract:	Genetically modified T cells that express a transduced T cell receptor (TCR) {alpha}/{beta} heterodimer in addition to their endogenous TCR are used in clinical studies to treat cancer. These cells express two TCR{alpha} and two TCR{beta} chains that do not only compete for CD3 proteins but also form potentially self-reactive mixed TCR dimers, composed of endogenous and transferred chains. To overcome these deficits we developed an RNAi-TCR replacement vector that simultaneously silences the endogenous TCR and expresses an RNAi-resistant TCR. Transduction of the virus-specific P14 TCR without RNAi resulted in unequal P14 TCR{alpha} and {beta} chain surface levels, indicating heterodimerization with endogenous TCR chains. Such unequal expression was also observed following TCR gene optimization. Equal surface levels of the introduced TCR chains were however achieved by silencing the endogenous TCR. Importantly, all mice that received cells transduced with the native or optimized P14 TCR developed lethal TCR gene transfer-induced graft-versus-host-disease (TI-GVHD) due to formation of mixed TCR dimers. In contrast, TI-GVHD was almost completely prevented when using the RNAi-TCR replacement vector. Our data demonstrate that RNAi-assisted TCR replacement reduces the formation of mixed TCR dimers, and thereby significantly reduces the risk of TI-GVHD in TCR gene therapy.
Keywords:	Animal Disease Models, Antigen, T-Cell Receptors, Autoimmunity, Cultured Cells, Experimental Melanoma, Gene Knockdown Techniques, Genetic Transduction, Genetic Vectors, Graft vs Host Disease, Lung Neoplasms, RNA Interference, T-Lymphocytes, Animals, Mice
Source:	Molecular Therapy
ISSN:	1525-0016
Publisher:	Nature Publishing Group
Volume:	22
Number:	11
Page Range:	1983-1991
Date:	November 2014
Official Publication:	https://doi.org/10.1038/mt.2014.142
PubMed:	View item in PubMed

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