Also – a quick plug that I am looking for scientist roles in biotech/pharma! Would love to connect at tinyurl.com/yjh-linkedin

Immense gratitude to my incredible coauthors @amylizbaxter.bsky.social @sasikanthmanne.bsky.social @ejohnwherry.bsky.social and many others not on bsky, past/present members of the Wherry lab, and editors at @science.org immunology. Thanks for reading - happy to address any questions!

Overall, we provide mechanistic understanding of the molecular barriers that lock Tex into this fate. We hope these studies provide the foundation for future efforts to rewire Tex into customized cell fates for optimal disease control!

Second, TOX removal enables Tex fate flexibility. However, given the requirement for i) TOX for Tex survival and ii) external cues to induce Tex rewiring, therapeutic TOX targeting must be combined with approaches that promote both cell survival and Teff differentiation

First, the continued requirement for TOX in Tex survival supports a growing paradigm that the Tex program enables cells to survive chronic stress. By understanding Tex stress-resilience, these properties can be harnessed to promote therapeutic T cell persistence

Thus, TOX acts as a durable epigenetic barrier that safeguards the Tex fate by 1) maintaining epigenetics underlying Tex phenotypes and survival and 2) preventing external signals from diverting Tex to other cell fates. Multiple mechanistic and therapeutic implications:

Notably, TOX removal endowed established Tex with greater flexibility. In the presence of Teff-driving signals, TOX iKO Tex partially converted into Teff-like cells and acquired greater cytokine-producing and tumor-killing capacities.

Indeed, gene expression and epigenetic profiling revealed a role for TOX in maintaining key cellular processes in Tex including mitochondrial function, along with Tex epigenetic programming underlying terminal differentiation and survival

Numerical loss of TOX iKO was reversed through opposing apoptosis via concurrent BIM and TOX targeting. However, “rescued” TOX iKO did not regain inhibitory receptor expression, suggesting that TOX preserves both Tex survival and ongoing Tex programming

Here, we identified TOX as a key epigenetic factor that preserves Tex biology. Induced TOX deletion in established Tex (TOX iKO) resulted in apoptosis-driven reduction in Tex number and loss of key Tex features (e.g., PD-1, terminal differentiation)

Established Tex lose plasticity and cannot be redirected to other fates (e.g., effector (Teff)). Checkpoint blockade only transiently boosts Tex function before they revert to a suppressed state, highlighting a need to better understand mechanisms limiting Tex fate flexibility.