A distinct innate lymphoid cell population regulates tumor-associated T cells

Sarah Q Crome, Linh T Nguyen, Sandra Lopez-Verges, S Y Cindy Yang, Bernard Martin, Jennifer Y Yam, Dylan J Johnson, Jessica Nie, Michael Pniak, Pei Hua Yen, Anca Milea, Ramlogan Sowamber, Sarah Rachel Katz, Marcus Q Bernardini, Blaise A Clarke, Patricia A Shaw, Philipp A Lang, Hal K Berman, Trevor J Pugh, Lewis L Lanier, Pamela S Ohashi

Antitumor T cells are subject to multiple mechanisms of negative regulation. Recent findings that innate lymphoid cells (ILCs) regulate adaptive T cell responses led us to examine the regulatory potential of ILCs in the context of cancer. We identified a unique ILC population that inhibits tumor-infiltrating lymphocytes (TILs) from high-grade serous tumors, defined their suppressive capacity in vitro, and performed a comprehensive analysis of their phenotype. Notably, the presence of this CD56(+)CD3(-) population in TIL cultures was associated with reduced T cell numbers, and further functional studies demonstrated that this population suppressed TIL expansion and altered TIL cytokine production. Transcriptome analysis and phenotypic characterization determined that regulatory CD56(+)CD3(-) cells exhibit low cytotoxic activity, produce IL-22, and have an expression profile that overlaps with those of natural killer (NK) cells and other ILCs. NKp46 was highly expressed by these cells, and addition of anti-NKp46 antibodies to TIL cultures abrogated the ability of these regulatory ILCs to suppress T cell expansion. Notably, the presence of these regulatory ILCs in TIL cultures corresponded with a striking reduction in the time to disease recurrence. These studies demonstrate that a previously uncharacterized ILC population regulates the activity and expansion of tumor-associated T cells.