?? T Cell-Mediated Antibody-Dependent Cellular Cytotoxicity with CD19 Antibodies Assessed by an Impedance-Based Label-Free Real-Time Cytotoxicity Assay.

ABSTRACT: ?? 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 ?? T cells promising effector cells for antibody-based immunotherapy in pediatric patients with B-lineage acute lymphoblastic leukemia (ALL). To evaluate combination of human ?? T cells with CD19 antibodies for immunotherapy of B-lineage ALL, ?? T cells were expanded after a GMP-compliant protocol and ADCC of both primary and expanded ?? 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, TNF?, and IFN? expression of primary ?? T cells were significantly increased and correlated with CD16-expression of ?? T cells. ?? T cells highly expressed CD107a after expansion and no further increased expression by 4G7SDIE and N19-C16 was measured. Cytotoxicity of purified expanded ?? 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 ?? 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 ?? 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 ?? T cells over prolonged periods of time periods. Combination of CD19 antibodies with primary as well as expanded ?? T cells exhibits a promising approach, which may enhance clinical outcome of patients with pediatric B-lineage ALL and requires clinical evaluation.

SUBMITTER: Seidel UJ 

PROVIDER: S-EPMC4251440 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature