IgM anti-ganglioside antibodies induced by melanoma cell vaccine correlatewith survival of melanoma patients

Melanoma cells express ganglioside antigens GM3, GD3, GM2, and GD2 on their surface. This study examined whether immunization with a melanoma cell vac cine induced anti-ganglioside antibody responses in :melanoma patients and whether these responses were correlated with survival, Sixty-six patients w ho had received melanoma cell vaccine immunotherapy after surgical removal of regional metastatic melanoma were identified. Cryopreserved serum sample s from these patients were used in an enzyme-linked immunsorbent assay to d etermine the IgM antibody levels to GM2, GD2, GM3, and GD3 prior to melanom a cell vaccine treatment and 4 wk after the first melanoma cell vaccine imm unization. All antibody levels significantly increased by week 4 (p < 0.001 for all four antibodies) and all increases were significantly associated w ith survival (anti-GD2, p < 0.001; anti-GM2, p = 0.001; anti-GD3, p < 0.001 ; anti-GM3, p < 0.001), Anti-tumor activity of these antibodies was proved using five representative antibody-positive sera in a complement-dependent cyto-toxicity assay with cultured melanoma cell lines. These studies sugges t that GM2, GD2, GM2, and GD3 expressed by melanoma cells can induce specif ic IgM antibodies and that high levels of these antibodies might have a ben eficial impact on survival.