Genome-scale perturb-seq in primary human CD4+ T cells reveals genes regulating T cell programs and human immune traits.

CD4+ T cells orchestrate immune responses against infection and cancer, yet a comprehensive map of their gene regulatory networks has been lacking. Perturb-seq enables systematic mapping of such networks, but large-scale application in primary human T cells has been challenging. Here, we developed a scalable, probe-based Perturb-seq platform and performed genome-scale perturbations of all expressed genes across 22 million primary CD4+ T cells from four donors under three stimulation conditions. We demonstrate the utility of this dataset in three ways. First, we identify previously unrecognized regulators of the two important immune cytokines, IL-10 and IL-21. Second, we show that ex vivo perturbation signatures can model T cell states observed in population-scale atlases, revealing regulators of helper T cell polarization and T cell aging. Third, we leverage regulatory relationships to mechanistically explain gene–trait associations in immune-related diseases, nominating genes for uncharacterized immune functions. Thus genome-scale perturb-seq in primary human T cells provides a foundational resource for decoding immune variation in humans and reprogramming T cell states for next-generation precision therapies.