Induction of cellular immunity by anti-idiotypic antibodies mimicking GD2 ganglioside

Gangliosides are potentially useful targets for tumor destruction by antibodies. However, the role of gangliosides in T cell-mediated immunity to tumors is unclear. We produced three murine monoclonal anti-idiotypic antibodies (Ab2) against a monoclonal antibody (Ab1) that binds strongly to melanoma-associated GD2 ganglioside and weakly to GD3 ganglioside. All three Ab2 induced anti-anti-idiotypic antibodies (Ab3) with Ab1-like binding specificity to tumor cells and antigen in rabbits. The Ab3 specifically bound to GD2(+) tumor cells and isolated GD2, and shared idiotopes with the Ab1. Two of the three Ab2 induced GD2-specific delayed-type hypersensitivity responses in BALB/c and C57BL/6 mice, but not in C57BL/6/CD4(-/-) mice. Peripheral blood mononuclear cells (PBMC) from a melanoma patient proliferated specifically in response to in vitro stimulation with Ab2. Proliferation was accompanied by Th1-type cytokine production. Our studies demonstrate the induction of ganglioside-specific T cell-dependent immunity by Ab2 in mice. These T cells showed specific reactivity to ganglioside expressed by tumor cells.