Extended Data Figure 10: Intratumoural inhibition of T cell effector function via an ionic checkpoint.

a, Healthy tissue contains limited local cellular decay, maintaining the interstitial [K⁺]_e close to serum levels. T cells are robustly activated following TCR stimulation. b, Tumour-intrinsic phenomena produce a high density of cell death within cancers. Cell death leads to release of intracellular K⁺ into the extracellular space. The resultant elevated [K⁺]_e acts to increase the [K⁺]_i of T cells, limiting their activation and effector function. c, Reduction of [K⁺]_i and increased effector function can be imparted to tumour-specific T cells by overexpression of K_v1.3 (Kcna3).