Bispecific antibodies enhance tumor-infiltrating T cell cytotoxicity against autologous HER-2-expressing high-grade ovarian tumors

Abstract

Epithelial ovarian cancer displays the highest mortality of all gynecological tumors. A relapse of the disease even after successful surgical treatment is a significant problem. Resistance against the current platinum‐based chemotherapeutic standard regime requires a detailed ex vivo immune profiling of tumor‐infiltrating cells and the development of new therapeutic strategies. In this study, we phenotypically and functionally characterize tumor cells and autologous tumor‐derived αβ and γδ T lymphocyte subsets. Tumor‐infiltrating (TIL) and tumor‐ascites lymphocytes (TAL) were ex vivo isolated out of tumor tissue and ascites, respectively, from high‐grade ovarian carcinoma patients (FIGO‐stage IIIa‐IV). We observed an increased γδ T cell percentage in ascites compared to tumor‐tissue and blood of these patients, whereas CD8+ αβ T cells were increased within TAL and TIL. The number of Vδ1 and non‐Vδ1/Vδ2‐expressing γδ T cells was increased in the ascites and in the tumor tissue compared to the blood of the same donors. Commonly in PBL, the Vγ9 chain of the γδ T cell receptor is usually associated exclusively with the Vδ2 chain. Interestingly, we detected Vδ1 and non‐Vδ1/Vδ2 T cells co‐expressing Vγ9, which is so far not described for TAL and TIL. Importantly, our data demonstrated an expression of human epidermal growth factor receptor (HER)‐2 on high‐grade ovarian tumors, which can serve as an efficient tumor antigen to target CD3 TIL or selectively Vγ9‐expressing γδ T cells by bispecific antibodies (bsAbs) to ovarian cancer cells. Our bsAbs efficiently enhance cytotoxicity of TIL and TAL against autologous HER‐2‐expressing ovarian cells.

Cancer immunotherapy with γδ T cells: many paths ahead of us

“…A comparison between γδ T cells within the TILs and peripheral blood of the same patient frequently revealed an altered γδ T cell subset distribution across different tumor entities, with higher proportions of Vδ1T cells being present in the tumor than in the blood. 68 , 75 – 77 Of particular interest is the functional analysis of γδ TILs and their TCR repertoire in comparison to blood to determine whether there is preferential recruitment of clonal γδ T cells to the tumor site. In different tumors, γδ TILs frequently produce IFN-γ, 68 , 77 and no major difference was observed in this respect between Vδ1 and Vδ2 TILs in an ovarian cancer study.…”

Vγ9Vδ2 T Cells: Can We Re-Purpose a Potent Anti-Infection Mechanism for Cancer Therapy?

“…The strong cytolytic activity of Vγ9Vδ2 T cells is not only directed towards cells with intracellular bacterial infection but also against the pathogen itself. Effector functions of γδ T-cells includes induction of CD95/ CD95-Ligand and Tumor Necrosis Factor Related Apoptosis Inducing Ligand (TRAIL)/ TRAIL-Receptor (R) signaling to induce target cell apoptosis [60,61] and secretion of cytotoxic substances, including granzyme, granulysin and perforins, which are active against both the infected host cell as well as the pathogen [62][63][64]. Hence, the recognition of BTN3A activated by phosphoantigens can elicit cytotoxic effector functions of Vγ9Vδ2 T cells.…”

“…In the context of cancer therapy, it is now possible to highly enrich autologous cells by ex vivo expansion and re-infuse them into a cancer patient. This leads to elevated amounts of γδ T effector cells, which, otherwise, are not found in comparable abundance in cancer patients, especially when compared to the high numbers of CD8 + TCRαβ + T-effector cells in the peripheral blood [64,98]. Subsequently, ex vivo expanded Vγ9Vδ2 T cells have been repeatedly used in early clinical Phase I adoptive transfer studies over the past 15 years ( Table 1).…”

“…An appealing way to bring complexity to tumor models while even maintaining immune cell diversity in a completely human setting are patient-derived ex vivo co-culturing experiments. Tumors of cancer patients removed during surgery were dissected and singularized tumor tissues as described elsewhere [64]. In brief, primary tumor tissue derived tumor cells and tumor-associated cells can be co-cultured with autologous isolated tumor-infiltrating cells (TIL) or autologous or allogeneic PBMC.…”

“…Hence, other than in the above-described in vivo adoptive T-cell transfer in mouse studies, here the complexity of the tumor intrinsic immune system is largely maintained in an autologous, human system, which reflects the composition and phenotype of the different cells within the tumor tissue. Ex vivo cultivation of the original mixture of tumor cells and TILs with or without the addition of autologous PBMCs allows the more closely monitoring of the cytokine-or cytotoxic mediator expression using multicolor flow cytometry [64,134]. The cytotoxic activity of effector cells within the tumor tissue can be analyzed by applying the tumor tissue to a Real Time Cell Analyzer (RTCA, X-Celligence, ACEA Biosciences, San Diego, CA, USA), which allows measurement over an extended time course as described elsewhere [166].…”