Multimodal delineation of a layer of effector function among exhausted CD8 T cells in tumors.

Undescribed functional axes may intersect with the trajectory of T cell exhaustion (T) to contribute to the antitumoral functions of CD8 T cells. By leveraging fluorescent transcriptional reporting of the T cell activation marker , we defined a classifier for potent versus suboptimal CD69 activation states arising from T cell stimulation. In tumors, this delineation provided an additional functional readout among T subsets, marked by enhanced effector molecule production. The more potent -TFP state was the most prominent in a T cell-mediated tumor clearance model, displaying increased engagement and superior tumor cell killing. Simultaneous analysis of gene and protein expression in human head and neck tumors enabled a similar strategy to identify RNACD69 cells with enhanced functional features compared with RNACD69 cells among intratumoral CD8 T cell subsets. Thus, refining the T cell functional landscape in tumors potentiates the identification of rare, potent effectors that could be leveraged for improving cancer treatment.