Monoclonal antibody-dependent, cell-mediated cytotoxicity against human malignant gliomas

Two monoclonal antibodies (MAbs), IgG2a MAb ASHG4 and IgG2b MAb ASHE2, were produced in mice immunized with cultured human malignant glioma cells. Both MAbs bound strongly to the surfaces of long-term cultured glioma cells, and MAb ASHE2 also bound strongly to short-term cultured glioma cells. Sections of frozen glioma tissues bound both MAbs strongly, whereas normal brain tissues showed weaker reactivities, and tissues derived from carcinomas of various histological types were completely unreactive. Furthermore, the MAbs did not bind to peripheral blood cells or bone marrow cells. Although both MAbs bound to the same Mr 27,000-29,000 protein, they may detect different or overlapping epitopes on this antigen. Because MAbs ASHE2 and ASHG4 lysed cultured glioma cells with human peripheral blood lymphocytes as effector cells, they are promising reagents for approaches to immunotherapy of human malignant gliomas.