title: γδ T Cell-Mediated Antibody-Dependent Cellular Cytotoxicity with CD19 Antibodies Assessed by an Impedance-Based Label-Free Real-Time Cytotoxicity Assay.
abstract: γδ T cells are not MHC restricted, elicit cytotoxicity against various malignancies, are present in early post-transplant phases in novel stem cell transplantation strategies and have been shown to mediate antibody-dependent cellular cytotoxicity (ADCC) with monoclonal antibodies (mAbs). These features make γδ T cells promising effector cells for antibody-based immunotherapy in pediatric patients with B-lineage acute lymphoblastic leukemia (ALL). To evaluate combination of human γδ T cells with CD19 antibodies for immunotherapy of B-lineage ALL, γδ T cells were expanded after a GMP-compliant protocol and ADCC of both primary and expanded γδ T cells with an Fc-optimized CD19 antibody (4G7SDIE) and a bi-specific antibody with the specificities CD19 and CD16 (N19-C16) was evaluated in CD107a-degranulation assays and intracellular cytokine staining. CD107a, TNFα, and IFNγ expression of primary γδ T cells were significantly increased and correlated with CD16-expression of γδ T cells. γδ T cells highly expressed CD107a after expansion and no further increased expression by 4G7SDIE and N19-C16 was measured. Cytotoxicity of purified expanded γδ T cells targeting CD19-expressing cells was assessed in both europium-TDA release and in an impedance-based label-free method (using the xCELLigence system) measuring γδ T cell lysis in real-time. Albeit in the 2 h end-point europium-TDA release assay no increased lysis was observed, in real-time xCELLigence assays both significant antibody-independent cytotoxicity and ADCC of γδ T cells were observed. The xCELLigence system outperformed the end-point europium-TDA release assay in sensitivity and allows drawing of conclusions to lysis kinetics of γδ T cells over prolonged periods of time periods. Combination of CD19 antibodies with primary as well as expanded γδ T cells exhibits a promising approach, which may enhance clinical outcome of patients with pediatric B-lineage ALL and requires clinical evaluation.
authors.affiliation: Department of General Paediatrics, Oncology/Haematology, University Children's Hospital Tübingen , Tübingen , Germany.
authors.forename: Ursula Jördis Eva
authors.initials: UJ
authors.lastname: Seidel
authors.affiliation: Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen , Tübingen , Germany ; Partner Site Tübingen, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) , Tübingen , Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Vogt
authors.affiliation: Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen , Tübingen , Germany ; SYNIMMUNE GmbH , Tübingen , Germany.
authors.forename: Ludger
authors.initials: L
authors.lastname: Grosse-Hovest
authors.affiliation: Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen , Tübingen , Germany ; Partner Site Tübingen, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) , Tübingen , Germany.
authors.forename: Gundram
authors.initials: G
authors.lastname: Jung
authors.affiliation: Department of General Paediatrics, Oncology/Haematology, University Children's Hospital Tübingen , Tübingen , Germany ; Partner Site Tübingen, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) , Tübingen , Germany.
authors.forename: Rupert
authors.initials: R
authors.lastname: Handgretinger
authors.affiliation: Department of General Paediatrics, Oncology/Haematology, University Children's Hospital Tübingen , Tübingen , Germany ; Partner Site Tübingen, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) , Tübingen , Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Lang
keywords: ADCC; therapeutic antibodies; tumor immunotherapy; xCELLigence system; γδ T cell expansion