BATF and IRF4 cooperate to counter exhaustion in tumour-infiltrating CAR T cells

Abstract

Abstract Cooperative interactions among transcription factors are essential for gene transcription. We previously showed that NFAT and AP-1 (Fos-Jun) transcription factors cooperate to promote the effector functions of T cells, but that under conditions where it is unable to cooperate with AP-1, NFAT imposes a negative feedback programme of T cell hyporesponsiveness (“exhaustion”). Here we show that BATF and IRF4 cooperate to counter T cell exhaustion. Overexpression of Batf in CD8+ T cells expressing a chimeric antigen receptor (CAR) promoted the survival and expansion of tumour-infiltrating CAR T cells, increased their production of effector cytokines, decreased their expression of inhibitory receptors and the exhaustion-associated transcription factor TOX, and led to the generation of long-lived memory T cells that controlled tumour recurrence. These responses were dependent on the BATF-IRF interaction, since cells expressing a Batf mutant unable to interact with Irf4 did not survive in tumours and did not effectively delay tumour growth. We suggest that BATF overexpression is a therapeutically viable option for improving the anti-tumour responses of CAR TILs, by skewing their phenotypes and transcriptional profiles away from exhaustion and towards increased effector function.