BCOR and ZC3H12A suppress a core stemness program in exhausted CD8⁺ T cells

In chronic viral infections, sustained CD8⁺ T cell response relies on TCF1⁺ precursor-exhausted T cells (T_PEX) exhibiting stem-like properties. T_PEX self-renew and respond to PD-1 blockade, underscoring their paramount importance. However, strategies for effectively augmenting T_PEX remain limited. Here, we demonstrate that ZC3H12A deficiency initiates a stemness program in T_PEX but also increases cell death, whereas BCOR deficiency predominantly promotes T_PEX proliferation. Consequently, co-targeting of both BCOR and ZC3H12A imparts exceptional stemness and functionality to T_PEX, thereby enhancing viral control. Mechanistically, BCOR and ZC3H12A collaboratively suppress a core stemness program in T_PEX characterized by heightened expression of ∼216 factors. While TCF1 plays a role, this core stemness program relies on novel factors, including PDZK1IP1, IFIT3, PIM2, LTB, and POU2F2. Crucially, overexpressing POU2F2 robustly boosts T_PEX and enhances antiviral immunity. Thus, a core stemness program exists in exhausted T cells, jointly repressed by BCOR and ZC3H12A, robustly controlling T_PEX differentiation and providing new targets for addressing T cell exhaustion.