Human neuroblastomas and gliomas express high levels of GD2 ganglioside. Mechanisms for the re-expression of GD2 after the incorporation of an exogenous precursor structure were analyzed using a human heterophilic monoclonal antibody (mAb) together with mouse anti-GD3 and mouse anti-GD2 mAbs. First, mouse anti-GD2 mAb 220-51 was generated and its reactivity was confirmed to be almost identical with that of the well-known mAb 3F8 antibody. As reported previously for GD3 variants, new ganglioside antigens reactive with human mAb 32-27 were analyzed by culturing an astrocytoma cell line AS in the presence of NeuGc-GM3. Analysis of the extracted gangliosides from AS thus cultured revealed a new component detected with mAb 32-27, migrating similarly to GD2. Incorporated NeuGc-GM3 seemed to be converted to NeuAc-NeuGc-type GD3, and then to NeuAc-NeuGc-type GD2 with alpha2,8-sialyltransferase and beta1,4-GalNAc transferase, respectively. In addition, AS was inoculated into nude mice, and glycolipids were extracted from generated tumors. Analysis of the ganglioside components using mAbs indicated that NeuAc-NeuGc-type GD2 was generated in the xenogeneic tumors by incorporating NeuGc-GM3 from mouse blood. These results indicated the presence of a pathway for utilization of exogenous gangliosides for remodeling and re-expression in vivo.