Systematic analysis of CD39, CD103, CD137 and PD-1 as biomarkers for naturally occurring tumor antigen-specific TILs

Abstract

The detection of tumor-specific T cells in solid tumors is integral to the interrogation of endogenous antitumor responses and to the advancement of downstream therapeutic applications, such as checkpoint immunotherapy and adoptive cell transfer. A number of biomarkers are reported to identify endogenous tumor-specific tumor infiltrating lymphocytes (TILs), namely CD137, PD-1, CD103, and CD39, however a direct comparison of these molecules has yet to be performed. Here, we evaluate these biomarkers in primary human high-grade serous ovarian tumor samples using single-cell mass cytometry to characterize and compare their relative phenotypic profiles, as well as their response to autologous tumor cells ex vivo. CD137+, PD-1+, CD103+, and CD39+ TILs are all detectable in tumor samples with CD137+ TILs being the least abundant. PD-1+, CD103+, and CD39+ TILs all express a subset of CD137+ cells, while CD137+ TILs highly co-express the aforementioned markers. CD137+ TILs exhibit the highest expression of cytotoxic effector molecules, such as IFNg and Granzyme B, compared to PD-1+, CD103+ or CD39+ TILs. Removal of CD137+ TILs from PD-1+, CD103+, or CD39+ TILs results in lower secretion of IFNg in response to autologous tumor stimulation, while CD137+ TILs highly secrete IFNg in an HLA-dependent manner. CD137+ TILs exhibited an exhausted phenotype with CD28 co-expression, suggestive of antigen recognition and receptiveness to reinvigoration via immune checkpoint blockade. Together, our findings demonstrate that the antitumor abilities of PD-1+, CD103+, and CD39+ TILs are mainly derived from a subset of TILs expressing CD137, implicating CD137 is a more selective biomarker for naturally occurring tumor-specific TILs.

CD39 is expressed on functional effector and tissue resident memory CD8+ T cells

“…4b,c). In agreement with previous reports 20, 22,[24][25][26][27]28 , total tumor-specific CD8+ T cells had increased CD39 expression compared to total virus-specific T cells (Fig 4j). However, when cells were subset by CD69 expression, CD69+ virus-specific T cells expressed increased levels of CD39 compared to tumor-specific T cells (Supplemental Fig.…”

“…In individuals with HIV and HCV, CD39 expression on circulating virus-specific T cells correlated with increased viral load and reduced functionality 19 . In line with this association of CD39+ T cells and chronic antigen, CD39 has recently been identified as a marker of tumor-specific CD8+ T cells in several human tumors 20,22,[24][25][26][27]28 . We and others have shown that tumor infiltrating lymphocytes (TILs) can have specificity for cancer unrelated antigens and thus CD39 may allow discrimination of tumor-specific T cells from these bystander T cells 20,29 .…”

CD39 + tissue-resident memory CD8 + T cells with a clonal overlap across compartments mediate antitumor immunity in breast cancer

“…To better define tumor antigen-specific CD8 + T cells, we stained for CD39, which is a marker of tumor antigen-specific CD8 + T cells in several types of cancers (17,(22)(23)(24)(25). CD39 expression was restricted in CD103 + T RM cells (fig.…”

“…CD39 is a marker for tumor antigen specificity (17,(22)(23)(24)(25) or exhaustion (26), especially terminal exhaustion (27,28). Although these concepts are related, their implications in the antitumor immune response can be interpreted differently.…”

Potential biomarkers: Identifying powerful tumor specific T cells in adoptive cellular therapy

“…Interestingly, the expanded products of CD137 + T cells in vitro secreted multiple cellular cytokines, including IFN-g, TNF-a and IL-2, after co-culture with a mixture of preferentially expressed antigen in melanoma-derived peptides, a specific tumor antigen upregulated in melanoma obtained from the peripheral blood of healthy donors (77). Recently, a systematic analysis of four biomarkers, PD-1, CD39, CD103 and CD137, in ovarian cancer TILs found that PD-1 + , CD39 + and CD103 + TILs all contained a subpopulation of CD137 + T cells and CD137 + TILs highly coexpressed the three previous markers, with the highest expression of major histocompatibility complex (MHC)-dependent IFN-g and other cellular effector cytokines (78). In addition, this subpopulation also uniquely co-expressed the costimulatory molecule CD28, suggesting that CD137 + TILs can recover stronger antitumor potential through combined immune checkpoint blockade (79).…”