The anti-idiotype (Id) monoclonal antibody (mAb) 1A7 immunoglobulin G1 (IgG1, kappa), raised in syngeneic mice against the murine anti-ganglioside GD2 mAb 14G2a mimics a carbohydrate epitope on GD2 and serves as a surrogate protein antigen for this disialoganglioside. Immunization of allogeneic C57BL/6 mice and rabbits with 1A7 induced anti-GD2 antibodies of IgG isotype that recognize purified GD2 by enzyme-linked immunosorbent assay (ELISA) and GD2-positive human melanoma cells (M21/P6) by fluorescence-activated cell sorter (FACS) analysis. The specificity of the antisera for GD2 was further confirmed by dot-blot analysis. These antisera also specifically lyse GD2-positive M21/P6 target cells in an antibody-dependent cellular cytotoxicity assay. Taken together, these results suggest that the anti-Id 1A7 can induce GD2-specific IgG antibodies that can recognize cell surface-associated as well as soluble disialoganglioside GD2.