Antigen‐specific TCR‐T cells from Rag2 gene‐deleted pluripotent stem cells impede solid tumour growth in a mouse model

The technology of adoptive transfer of T‐cell receptor (TCR) engineered T cells is wildly investigated as it has the potential to treat solid cancers. However, the therapeutic application of TCR‐T cells is hampered by the poor quality derived mainly from patients' peripheral blood, as well as heterogeneous TCRs caused by the mismatch between transgenic and endogenous TCRs. To improve the homogeneity, antigen‐specificity and reduce possible autoreactivity, here we developed a technique to generate antigen‐specific T cells from Rag2 gene‐deleted pluripotent stem cells (PSCs) and further measured their anti‐tumour efficacy. PSCs were first targeted with OT1 TCR into the Rag2 locus to prevent TCR rearrangement during T‐cell development. The engineered PSCs were then differentiated through a two‐step strategy, in vitro generation of haematopoietic progenitor cells, and in vivo development and maturation of TCR‐T cells. Finally, the response to tumour cells was assessed in vitro and in vivo. The regenerated OT1‐iT displayed monoclonal antigen‐specific TCR expression, and phonotypic normalities in the spleen and lymph node tissues. Importantly, the OT1‐iT cells eliminated tumour cells while releasing specific cytokines in vitro. Furthermore, adoptive transfer of OT1‐iT cells suppresses solid tumour growth in tumour‐bearing animals. Our study presents a novel and straightforward strategy for producing antigen‐specific TCR‐T cells in vivo from PSCs, allowing for allogeneic transplantation and therapy of solid tumours.