Anti-CD3 × anti-GD2 bispecific antibody redirects T-cell cytolytic activity to neuroblastoma targets.

The ganglioside GD2 is an attractive target for immunotherapy of neuroectodermal tumors. We tested a unique bispecific antibody anti-CD3 × anti-GD2 (3F8BiAb) for its ability to redirect activated T cells (ATC) to target GD2-positive neuroblastomas. ATC were generated from normal human peripheral blood mononuclear cells (PBMC) by stimulating the PBMC with OKT3 and expanding the T cells in the presence of interleukin 2 (IL-2) for 14 days. ATC were armed with 3F8BiAb (100 ng/10(6)  cells) or Her2BiAb (50 ng/10(6)  cells) prior to use. 3F8 BiAb were tested for its dual-binding specificity to GD2 expressed on cancer cell lines and CD3 expressed on ATC. 3F8BiAb-armed ATC were further tested ex vivo for their cytotoxicity against GD2 positive tumor targets and its ability to induce cytokine response upon binding to targets. GD2 expression in neuroblastoma cells was confirmed by FACS analysis. Specific binding of 3F8BiAb to the tumor targets as well as to ATC was confirmed by FACS analysis. 3F8BiAb-armed ATC exhibited specific killing of GD2 positive neuroblastoma cell lines significantly above unarmed ATC (P < 0.001). GD2BiAb-armed ATC secreted significantly higher levels of Th(1) cytokines and chemokines compared to unarmed ATC (P < 0.001). These preclinical findings support the potential of a novel immunotherapeutic approach to target T cells to neuroblastoma.