Purpose: Although considerable progress has been made with autologous T cell-based therapy in B-cell malignancies, application in chronic lymphocytic leukemia (CLL) lags behind due to disappointing... Show morePurpose: Although considerable progress has been made with autologous T cell-based therapy in B-cell malignancies, application in chronic lymphocytic leukemia (CLL) lags behind due to disappointing response rates as well as substantial toxicity that is of particular concern in the elderly CLL population. V gamma 9V delta 2-T cells form a conserved T-cell subset with strong intrinsic immunotherapeutic potential, largely because of their capacity to be triggered by phosphoantigens that can be overproduced by CLL and other malignant cells. Specific activation of V gamma 9V delta 2-T cells by a bispecific antibody may improve the efficacy and toxicity of autologous T-cell-based therapy in CLL.Experimental Design: We evaluated CD1d expression in a cohort of 78 untreated patients with CLL and generated and functionally characterized a CD1d-specific V gamma 9V delta 2-T cell engager based on single-domain antibodies (VHH).Results: CD1d was expressed by CLL in the majority of patients, particularly in patients with advanced disease. The CD1d-specific V gamma 9V delta 2-T cell engager induced robust activation and degranulation of V gamma 9V delta 2- T cells, enabling V gamma 9V delta 2-T cells from patients with CLL to lyse autologous leukemic cells at low effector-to-target ratios. Expression of CD1d on CLL cells is upregulated by all-trans retinoic acid, and sensitizes the malignant cells to bispecific VHH-induced lysis. Furthermore, we provide evidence that the V gamma 9V delta 2-T cell receptor retains responsiveness to phosphoantigens when the bispecific VHH is bound, and aminobisphosphonates can therefore enhance bispecific V gamma 9V delta 2-T cell engager-mediated tumor-specific killing.Conclusions: Collectively, our data demonstrate the immunotherapeutic potential of this novel CD1d-specific V gamma 9V delta 2-T cell engager in CLL. Show less
Weerdt, I. de; Lameris, R.; Scheffer, G.L.; Vree, J.; Boer, R. de; Stam, A.G.; ... ; Vliet, H.J. van der 2021
Novel T cell-based therapies for the treatment of B-cell malignancies, such as chronic lymphocytic leukemia (CLL) and multiple myeloma (MM), are thought to have strong potential. Progress, however,... Show moreNovel T cell-based therapies for the treatment of B-cell malignancies, such as chronic lymphocytic leukemia (CLL) and multiple myeloma (MM), are thought to have strong potential. Progress, however, has been hampered by low efficacy and high toxicity. Tumor targeting by V gamma 9V delta 2 T cells, a conserved T-cell subset with potent intrinsic antitumor properties, mediated by a bispecific antibody represents a novel approach promising high efficacy with limited toxicity. Here, we describe the generation of a bispecific V gamma 9V delta 2 T-cell engager directed against CD40, which, due to its overexpression and biological footprint in malignant B cells, represents an attractive target. The CD40-targeting moiety of the bispecific antibody was selected because it can prevent CD4OL-induced prosurvival signaling and reduce CD40-mediated resistance of CLL cells to venetoclax. Selective activation of V gamma 9V delta 2 T cells in the presence of CD40(+) tumor cells induced potent V gamma 9V delta 2 T-cell degranulation, cytotoxicity against CLL and MM cells in vitro, and in vivo control of MM in a xenograft model. The CD40-bispecific gamma delta T-cell engager demonstrated lysis of leukemic cells by autologous V gamma 9V delta 2 T cells present in patient-derived samples. Taken together, our CD40 bispecific gamma delta T-cell engager increased the sensitivity of leukemic cells to apoptosis and induced a potent V gamma 9V delta 2 T cell-dependent antileukemic response. It may, therefore, represent a potential candidate for the development of novel treatments for B-cell malignancies. Show less
