Mini-TCRs: Truncated T cell receptors to generate T cells from induced pluripotent stem cells

Abstract

Allogeneic Tcell platforms utilizing induced pluripotent stemcell (iPSC) technology exhibit significant promise for the facilitation of adoptive immunotherapies. While mature Tcell receptor (TCR) signaling plays a crucial role in generating Tcells from iPSCs, the introduction of exogenous mature TCR genes carries a potential risk of causing graft-versus-host disease (GvHD). In this study, we present the development of truncated TCRα and TCRβ chains, termed mini-TCRs, which lack variable domains responsible for recognizing human leukocyte antigen (HLA)-peptide complexes. We successfully induced cytotoxic T lymphocytes (CTLs) from iPSCs by employing mini-TCRs. Combinations of TCRα and TCRβ fragments were screened from mini-TCR libraries based on the surface localization of CD3 proteins and their ability to transduce Tcell signaling. Consequently, mini-TCR-expressing iPSCs underwent physiological Tcell development, progressing from the CD4 and CD8 double-positive stage to the CD8 single-positive stage. The resulting iPSC-derived CTLs exhibited comparable cytokine production and cytotoxicity in comparison to that of full-length TCR-expressing T lymphocytes when chimeric antigen receptors (CARs) were expressed. These findings demonstrate the potential of mini-TCR-carrying iPSCs as a versatile platform for CAR Tcell therapy, offering a promising avenue for advancing adoptive immunotherapies.