Characterization of ascites- and tumor-infiltrating γδ T cells reveals distinct repertoires and a beneficial role in ovarian cancer

Abstract

The role of γδ T cells in antitumor immunity has been under investigation for the past two decades, but little is known about their contribution to clinical outcomes in patients. Here, we set out to define the clonotypic, phenotypic, and functional features of γδ T cells in peripheral blood, ascites, and metastatic tumor tissue from patients with advanced epithelial ovarian cancer. T cell receptor (TCR) sequencing of the γ chain revealed that tumor-infiltrating γδ T cells have a unique and skewed repertoire with high TCR diversity and low clonality. In contrast, ascites-derived γδ T cells presented a lower TCR diversity and higher clonality, suggesting a TCR-dependent clonal focusing at this site. Further investigation showed that tumor samples had abundant γδ T cells with a tissue-resident, activation-associated phenotype, less usage of Vγ9 and an impaired response to adaptive-associated stimuli, implying an innate-like activation pathway, rather than an adaptive TCR-engaging pathway, at these tumor sites. Furthermore, high γδ T cell cytokine responsiveness upon stimulation was associated with a favorable outcome for patients in terms of both overall survival and reduced residual tumor burden after primary surgery. Last, the functionality of γδ T cells and patient survival were negatively affected by the proportions of CD39-expressing T cells, highlighting the potential of CD39 as a target to improve γδ T cell responses and unleash their antitumor capabilities.

Phased differentiation of γδ T and T CD8 tumor-infiltrating lymphocytes revealed by single-cell transcriptomics of human cancers

“…Identifying the Tex and Ttrm cells in all tumors (Methods) showed their respective rates were correlated between the two lineages (Pearson r = 0.8 in both cases) (Figure 2d). Confirming recent reports, [7][8][9] the majority of γδ TILs cancer-wide was of TCRVγnon-9 subtype, reflecting the extra-lymphoid tropism of this subset (Figure 2e, Table S2b). Combining trajectory and signature analyses revealed that, like Tex T CD8 TILs, all the Tex γδ TILs displayed Tem or Tcm 2e, f).…”

“…31 This repartition disappears in tumors, however, where the TCRVγnon9 γδ TILs predominate in all (non-)hematopoietic cancer types. [7][8][9] Viral infections are major drivers of peripheral differentiation of T CD8 and γδ T lymphocytes. Thus, the locally phased differentiation of both γδ T and T CD8 lymphocytes strongly suggests a functional convergence toward effective antitumor immunity.…”

“…[4][5][6] Likewise, the presence, function, and potential of TCRVγnon9 cells which represent another prominent subset of γδ TILs are demonstrated in different human tumors. [7][8][9] So far, however, neither the general landscape of both subsets of cytolytic γδ TILs nor their putative link with the T CD8 had been characterized both at the single cell level and at a cancer-wide scale.…”

The Diverse Roles of γδ T Cells in Cancer: From Rapid Immunity to Aggressive Lymphoma

“…In human solid cancers, γδ tumour-infiltrating lymphocytes (TILs) have been proposed by many studies to be relevant prognostic factors; however, there appear to be differences in their anti-tumour functions across different solid cancer types. Notably, their tumour infiltration and cytolytic activity have been linked with a beneficial role for patient outcome in gastric cancer [ 121 , 122 ], hepatocellular carcinoma [ 68 ], ovarian cancer [ 123 ], colorectal cancer [ 124 , 125 ], renal cell carcinoma [ 126 , 127 ], glioblastoma [ 128 ] and triple-negative breast cancer [ 129 , 130 , 131 ]. On the other hand, they were also reported to have a negative impact on prognosis in ovarian cancer [ 37 ] and oral cancer [ 42 ], and conflicting studies also found them to positively correlate with pathogenesis in colon cancer [ 132 ] and breast cancer [ 133 , 134 ].…”

Single-Cell RNAseq Profiling of Human γδ T Lymphocytes in Virus-Related Cancers and COVID-19 Disease

“…In human cancer, our research and other studies have shown that the abundance of γδ TILs, whether TCRVγ9 or TCRVγnon9, varies substantially across individuals and among cancer types, and that it is associated with patient outcomes [22,23]. As opposed to peripheral blood and hematopoietic malignancies dominated by TCRVγ9 γδ T cells, the predominant subset of γδ TILs in most solid tumors are TCRVγnon9 cells, whose number, cytotoxic differentiation, and functional status vary between individuals [24][25][26].…”