Abstract 5011: generation of rejuvenated murine antigen-specific T cells by reprogramming to pluripotency and redifferentiation

Abstract

Abstract Background: Adoptive cell therapy with autologous antigen-specific T cells is a promising approach for treating patients with chronic viral infections and various cancers. A major limitation of this approach is the difficulty of obtaining sufficient numbers of T cells with the characteristics necessary for in vivo effectiveness. Less-differentiated T cells with long telomeres would be an ideal T-cell subset for adoptive T cell therapy; however, generating large numbers of these “young” T cells is problematic. This limitation of adoptive T cell therapy can be overcome by using induced pluripotent stem cells (iPSCs) that self-renew, maintain pluripotency, and provide an unlimited source of autologous T cells for immunotherapy. However, in vivo antitumor reactivity of iPSC-rejuvenated T cells remains unknown due to the lack of animal model. Methods: To establish preclinical model of evaluating iPSC-rejuvenated antigen-specific T cells, we reprogrammed OT-1 T cell receptor (TCR) transgenic CD8 T cells using Sendai virus vectors encoding Oct3/4, Sox2, Klf4 and c-Myc transcription factors. Pluripotency and differentiation capacity of generated iPSCs were evaluated. Results: Twenty days after infection with Sendai virus vectors, we obtained murine embryonic stem cell-like colonies from OT-1 CD8 T cells. Immunofluorescence staining and RT-PCR analyses revealed pluripotency of established colonies. The iPSCs formed embryoid bodies in vitro, and upregulation of marker genes for all three germ layers was detected. The iPSCs differentiated into teratomas in vivo comprising all three embryonic germ layers in immune-deficient NOD/SCID mice. The iPSCs retained the same rearranged configuration of TCR chain genes as the original OT-1 T cells. Furthermore, OT-1 T cell-derived iPSCs differentiated into T cells on delta-like ligand 1 expressing OP9 (OP9/DL1) murine bone marrow stromal cells. Conclusions: Generation of rejuvenated T cells by reprogramming to pluripotency and redifferentiation is feasible. This type of approach may be useful for adoptive T cell therapy. We acknowledge DNAVEC Corporation for kindly providing Sendai virus vectors. This study was supported by the University of Michigan Start-up fund. Citation Format: Fumito Ito, Noemi Fusaki, Hidehito Saito. generation of rejuvenated murine antigen-specific T cells by reprogramming to pluripotency and redifferentiation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5011. doi:10.1158/1538-7445.AM2015-5011