Anti-disialoganglioside GD2 IgG antibodies have shown clinical efficacy in solid tumors that lack human leukocyte antigens (e.g.， neuroblastoma) by relying on Fc-dependent cytotoxicity. However， there are pain side effects secondary to complement activation. T-cell retargeting bispecific antibodies (BsAb) also have clinical potential， but it is thus far only effective against liquid tumors. In this study， a fully humanized hu3F8-BsAb was developed， in which the anti-CD3 huOKT3 single-chain Fv fragment (ScFv) was linked to the carboxyl end of the anti-GD2 hu3F8 IgG1 light chain， and was aglycosylated at N297 of Fc to prevent complement activation and cytokine storm. In vitro， hu3F8-BsAb activated T cells through classic immunologic synapses， inducing GD2-specific tumor cytotoxicity at femtomolar EC50 with >10⁵-fold selectivity over normal tissues， releasing Th1 cytokines (TNFα， IFNγ， and IL2) when GD2⁺ tumors were present. In separate murine neuroblastoma and melanoma xenograft models， intravenous hu3F8-BsAb activated T cells in situ and recruited intravenous T cells for tumor ablation， significantly prolonging survival from local recurrence or from metastatic disease. Hu3F8-BsAb， but not control BsAb， drove T cells and monocytes to infiltrate tumor stroma. These monocytes were necessary for sustained T-cell proliferation and/or survival and contributed significantly to the antitumor effect. The in vitro and in vivo antitumor properties of hu3F8-BsAb and its safety profile support its further clinical development as a cancer therapeutic， and provide the rationale for exploring aglycosylated IgG-scFv as a structural platform for retargeting human T cells.