Intraepithelial ILC1-Like NK Cells Increase Lymphocyte Infiltration into the Tumor Microenvironment via the CXCL10 Axis.

Intraepithelial type 1 innate lymphoid cells (ieILC1s) are tissue-resident lymphocytes in the microenvironment of head and neck squamous cell carcinoma. Here, we evaluate how these cells influence T-cell trafficking to tumors. We generated cytotoxic ieILC1-like cells from natural killer (NK) cells in vitro. Using an in vivo tumor model, we show that intratumoral ieILC1-like NK cells induce greater T cell trafficking into the tumor. Co-culture of ieILC1-like NK cells with the tumor cells resulted in elevated CXCL10 in the supernatant. Flow cytometry demonstrated that ieILC1-like NK cells produce robust amounts of IFNy, a known CXCL10 inducer, while CXCL10 was produced by tumor cells. These results indicate ieILC1-like NK cells induce tumor production of CXCL10, a proinflammatory chemokine that promotes T cell infiltration into the TME. The role of ieILC1-like NK cells in modulating clinical responses to immune checkpoint blockade warrants investigation.