Adoptively transferred ex vivo expanded γδ-T cells mediate in vivo antitumor activity in preclinical mouse models of breast cancer

Abstract

In contrast to antigen-specific αβ-T cells (adaptive immune system), γδ-T cells can recognize and lyse malignantly transformed cells almost immediately upon encounter in a manner that does not require the recognition of tumor-specific antigens (innate immune system). Given the welldocumented capacity of γδ-T cells to innately kill a variety of malignant cells, efforts are now actively underway to exploit the antitumor properties of γδ-T cells for clinical purposes. Here, we present for the first time preclinical in vivo mouse models of γδ-T cell-based immunotherapy directed against breast cancer. These studies were explicitly designed to approximate clinical situations in which adoptively-transferred γδ-T cells would be employed therapeutically against breast cancer. Using radioisotope-labeled γδ-T cells, we first show that adoptively-transferred γδ-T cells localize to breast tumors in a mouse model (4T1 mammary adenocarcinoma) of human breast cancer. Moreover, by using an antibody directed against the γδ-T cell receptor (TCR) we determined that localization of adoptively-transferred γδ-T cells to tumor is a TCR-dependant process. Additionally, biodistribution studies revealed that adoptively-transferred γδ-T cells traffic differently in tumor-bearing mice compared to healthy with fewer γδ-T cells localizing into the spleens of tumor-bearing mice. Finally, in both syngeneic (4T1) and xenogeneic (2Lmp) models of breast cancer, we demonstrate that adoptively-transferred γδ-T cells are both effective against breast cancer and are otherwise welltolerated by treated animals. These findings provide a strong preclinical rationale for using ex vivo expanded adoptively-transferred γδ-T cells as a form of cell-based immunotherapy for the treatment of breast cancer. Additionally, these studies establish that clinically-applicable methods for radiolabeling γδ-T cells allows for the tracking of adoptively-transferred γδ-T cells in tumor-bearing hosts.

Harnessing γδ T cells in anticancer immunotherapy

“…33,No. 5 that chemotherapy-induced cell death elicits a tumor-specific immune response that controls residual tumor cells instead of inducing tolerance [40][41][42].…”

“…33,No. 5 Improving gd T cell function for combinatorial regimens with immunotherapy and chemotherapy Vg9Vd2 gd T cell-triggering may be ameliorated by combining TCR stimulation with engagement of NK receptors or TLRs [64].…”

“…In nude mice inoculated subcutaneously with nasopharyngeal carcinoma cell lines, infused human peripheral gd T cells could temporarily accumulate in tumors, causing a transient reduction in tumor growth [32]. In a preclinical breast tumor model, infused gd T cells traffic to breast tumors in a TCR-dependent manner and prevent tumor growth [33]. Another study using mice transplanted with HER-2 + human breast cancer cell lines has shown that in vivo activation of gd T cells (through bisphosphonates) enhances the efficacy of standard immunotherapy (administration of trastuzumab, a monoclonal antibody directed against HER2/neu receptors) [34].…”

IFN-γ enhances HOS and U2OS cell lines susceptibility to γδ T cell-mediated killing through the Fas/Fas ligand pathway

“…Unlike αβ T cells which require antigen processing and MHC-restricted peptide display by antigen-presenting cells, γδ T cells exhibit potent MHCunrestricted lytic activity against tumor cells [11]. After recognizing tumor cells, activating γδ T cells possess a repertoire of various killing pathways, including the release of cytotoxic granules, the production of cytokines and the ability to engage death receptors on the surface of target cells [12,13].Up to now, γδ T cells are capable of mediating cytotoxicity against many different tumor cells in vitro and in vivo [12,[14][15][16][17][18][19], suggesting their potential utility as anticancer therapy. IFN-γ is an immuno-modulating cytokine, which is capable of mediating several immune stimulatory effects relevant to the induction of cellular antitumor immunity, such as enhancing T and/or NK cell cytokine production, proliferation, and cytolytic activity [20,21].…”

Prospects for chimeric antigen receptor (CAR) γδ T cells: A potential game changer for adoptive T cell cancer immunotherapy

“…Furthermore, their biodistribution studies showed that adoptively transferred γδ T cells traffic differently in tumor-bearing mice compared to healthy with fewer γδ T cells localizing into the spleens of tumor-bearing mice. They concluded that their findings provide a robust preclinical evidence for using ex vivo expanded adoptively transferred γδ-T cells as a form of cell-based immunotherapy for the treatment of breast cancer (149). Ali et al demonstrated that the microbial phosphoantigen ( E )-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP) plus IL-2 treatment of macaques induced a prolonged major expansion of circulating Vγ2Vδ2 T cells that expressed CD8 and produced cytotoxic perforin.…”