A novel oncolytic neutrophil phenotype is induced by IL-10R inhibition

While the impact of neutrophils on antitumor T cells has been an active area of study, fewer studies have focused on the potential of neutrophils to directly impact tumor cells. Here we asked whether neutrophils have the capacity to directly kill tumor cells independently of T cells. We find that anti-CD40-based therapy, when combined with interleukin 10 (IL-10) receptor blockade, initiates a Batf3-dependent pathway in which IL-12 and interferon gamma (IFNγ) secretion results in oncolytic neutrophil activity. Using a combination of microscopy, single-cell, and functional assays, we observe that killing of tumor cells by neutrophils is dependent on physical contact and degranulation. This degranulation-mediated killing is associated with an atypical dynamic invasive neutrophil phenotype. In line with our preclinical findings, our phase 1 trial of anti-CD40 shows that circulating IL-12, IFNγ, and IL-10 increase in response to anti-CD40, while our phase 1b/2 PRINCE study shows that lower circulating IL-10 is associated with favorable overall survival specifically among anti-CD40-treated patients. Finally, we find that neutrophil expansion with granulocyte colony stimulating factor (G-CSF) is associated with improved overall survival specifically in patients treated with anti-CD40, suggesting that this pathway may be amenable to therapeutic intervention in patients with advanced cancer. C57BL/6 wild-type mice were intradermally inoculated with B16F10 murine melanoma cells on their flanks, and eight days later, they received Isotype control, anti-IL-10R alone, anti-CD40/Monophosphoryl Lipid A (CM), or a combination of anti-CD40/MPL/anti-IL-10R (CMI). Twelve hours post-treatment, the B16F10 tumors were harvested and processed into single-cell suspensions. Single-cell RNA sequencing (scRNA-Seq) was subsequently performed on these FACS-sorted cell suspensions.