Orthogonal Gene Engineering Enables Novel Synthetic States of Powerful Tumor-rejecting CD8+ T Cells Escaping Canonical Exhaustion

To date, no immunotherapy approaches have managed to fully overcome T-cell exhaustion, which remains a mandatory fate for chronically activated effector cells and a major therapeutic challenge. Understanding how to reprogram CD8+ TILs away from exhausted effector states remains an elusive goal. Our work provides for the first-time evidence that orthogonal gene-engineering of T cells to secrete an IL-2-variant binding the IL-2R and the alarmin IL-33 reprogrammed adoptively transferred T cells to acquire a novel, synthetic state, which deviated from canonical exhaustion and displayed superior effector functions. These cells successfully overcame homeostatic barriers in the host, and led – in the absence of lymphodepletion or exogenous cytokine support – to high levels of engraftment and tumor regression. Our work unlocks the novel opportunity of rationally engineering synthetic CD8+ T-cell states endowed with the ability to avoid exhaustion and control advanced solid tumors. CD45+ bulk TILs were independently sorted at at days 5 (T1), 12 (T2) and 26 (T3) post cell transfer Groups: Non-Treated tumor-bearing mice (G5); Mice received ACT using Untransduced OT1 T cells (G1);Mice received ACT using PD1d/IL2V-secreting OT1 (G2); Mice received ACT using PD1d/33-secreting OT1 (G3); Mice received ACT using PD1d/2V/33-secreting OT1 (G4)