Modeling of CD8 T Cell Exhaustion Enables CRISPR Screening to Reveal a Role for BHLHE40.

Identifying novel molecular mechanisms of exhausted CD8 T cells (T ) is a key goal of improving immunotherapy of cancer and other diseases. However, high-throughput interrogation of T can be costly and inefficient. models of T are easily customizable and quickly generate high cellular yield, offering an opportunity to perform CRISPR screening and other high-throughput assays. We established an model of chronic stimulation and benchmarked key phenotypic, functional, transcriptional, and epigenetic features against bona fide T . We leveraged this model of chronic stimulation in combination with pooled CRISPR screening to uncover transcriptional regulators of T cell exhaustion. This approach identified several transcription factors, including BHLHE40. and validation defined a role for BHLHE40 in regulating a key differentiation checkpoint between progenitor and intermediate subsets of T . By developing and benchmarking an model of T , we demonstrate the utility of mechanistically annotated models of T , in combination with high-throughput approaches, as a discovery pipeline to uncover novel T biology.