Human monoclonal antibody to ganglioside GD2-inhibited human melanoma xenograft.

A human IgM monoclonal antibody was produced in vitro against OFA-I-2, a human tumor membrane antigen. This antigen is expressed on tumors of neuroectodermal origin, and has been identified as the ganglioside GD2. This study examines the anti-tumor effect of the monoclonal antibody against a GD2-positive human melanoma cell line, M14, inoculated subcutaneously into athymic CD-1 nude mice. Tumor-free survival was prolonged markedly when the monoclonal antibody and M14 cells were inoculated simultaneously. When antibody and complement were also injected into established tumor nodules, M14 tumor growth was suppressed. However, intraperitoneal injection of the antibody did not alter the growth of the subcutaneously inoculated M14 cells. The antibody has no effect on the growth of a GD2-negative melanoma cell line, M24. These results indicate that the human monoclonal antibody to GD2 may be useful for the suppression of GD2-positive tumor cells in cancer patients if the tumor can be directly exposed to the antibody and complement.