Multimodal stimulation screens reveal unique and shared genes limiting T cell fitness.

Genes limiting T cell antitumor activity may serve as therapeutic targets. It has not been systematically studied whether there are regulators that uniquely or broadly contribute to T cell fitness. We perform genome-scale CRISPR-Cas9 knockout screens in primary CD8 T cells to uncover genes negatively impacting fitness upon three modes of stimulation: (1) intense, triggering activation-induced cell death (AICD); (2) acute, triggering expansion; (3) chronic, causing dysfunction. Besides established regulators, we uncover genes controlling T cell fitness either specifically or commonly upon differential stimulation. Dap5 ablation, ranking highly in all three screens, increases translation while enhancing tumor killing. Loss of Icam1 -mediated homotypic T cell clustering amplifies cell expansion and effector functions after both acute and intense stimulation. Lastly, Ctbp1 inactivation induces functional T cell persistence exclusively upon chronic stimulation. Our results functionally annotate fitness regulators based on their unique or shared contribution to traits limiting T cell antitumor activity. [Display omitted] • Multimodal screens identify T cell fitness regulators impeding antitumor activity • Dap5 ablation increases translation enhancing T cell fitness upon various stimulations • Perturbing ICAM1-LFA1-mediated T cell clustering amplifies T cell effector functions • Ctbp1 inactivation strengthens T cell persistence exclusively upon chronic stimulation Lin et al. perform multimodal genome-wide CRISPR knockout screens in primary CD8 T cells for genes controlling fitness upon differential stimulation. They identify Dap5 , Icam1 , and Ctbp1 , which are functionally annotated and characterized based on their unique or shared contribution to traits limiting T cell antitumor activity. [ABSTRACT FROM AUTHOR]