Generation of highly proliferative rejuvenated cytotoxic T cell clones through pluripotency reprogramming for adoptive immunotherapy

Adoptive immunotherapy has emerged as a powerful approach to cure cancer and chronic infections. Currently, the generation of a massive number of T cells that provide long-lasting immunity is challenged by exhaustion and differentiation-associated senescence, which inevitably arise during in vitro cloning and expansion. To circumvent these problems, several studies have proposed an induced pluripotent stem cell (iPSC)-mediated rejuvenation strategy to revitalize the exhausted/senescent T-cell clones. Because iPSC-derived cytotoxic T lymphocytes (iPSC-CTLs) generated via commonly used monolayer systems have unfavorable innate-like features such as aberrant natural killer (NK) activity and limited replication potential, we modified the redifferentiation culture to generate CD8ab+CD5+CCR7+CD45RA+CD56- adaptive iPSC-CTLs. The modified iPSC-CTLs exhibited early memory phenotype, including high replicative capacity and the ability to give rise to potent effector cells. In expansion culture with an optimized cytokine cocktail, iPSC-CTLs proliferated more than 10^15-fold in a feeder-free condition. Our redifferentiation and expansion package of early memory iPSC-CTLs could supply memory and effector T cells for both autologous and allogeneic immunotherapies. To examine expression of T cell-related genes in iPSC-CTLs, RNA-sequencing were conducted.