A genome-scale screen for synthetic drivers of T cell proliferation

The engineering of patient T-cells for adoptive cell therapies has revolutionised the treatment of several cancer types(1). However, further improvements are needed to increase response and cure rates. CRISPR-based loss-of-function screens have been limited to negative regulators of T-cell functions(2-1) and raise safety concerns due to permanent genome modification. Here we identify positive T-cell regulators via overexpression of ~12,000 barcoded human open reading frames (ORFs). The top-ranked genes increased primary human CD4+ and CD8+ T-cell proliferation, activation, and secretion of key cytokines like interleukin-2 and interferon-gamma. In addition, we developed a single-cell genomics method (OverCITE-seq) for high-throughput quantification of the transcriptome and surface antigens in ORF-engineered T-cells. The top-ranked ORF, lymphotoxin beta receptor (LTBR), is typically expressed in myeloid cells but absent in lymphocytes. When overexpressed in T-cells, LTBR induced profound transcriptional and epigenomic remodelling, increasing T-cell effector functions, as well as resistance to exhaustion in chronic stimulation settings, via constitutive activation of the canonical NF-κB pathway. LTBR and other top-ranked genes improved antigen-specific chimeric antigen receptor (CAR) T-cell and γδ T-cell responses, highlighting their potential for future cancer-agnostic therapies(5). Our results provide several strategies for improving next generation T-cell therapies via induction of new synthetic cell programmes.