[Detection of human osteosarcoma-associated antigens by monoclonal antibodies]

Hybrid cell lines have been derived from a fusion between mouse myeloma cell line, NS1/Ag 4-1, and spleen cells from BALB/c mice immunized with freshly resected osteosarcoma cells from an untreated patient. Of the 276 hybrids obtained, five secreted antibodies which bound to osteosarcoma tissues but not to autologous skin fibroblasts. Antibodies secreted by individual hybrids were tested for their reaction with a panel of human normal and tumor tissues in an immunofluorescence assay, and they displayed different specificities. Two of these antibodies, OST2 and OST4, bound to osteosarcoma tissues and to some other tumors and normal tissues. The antibodies from three of these five hybrids, OST6, OST7, and OST15, reacted with all of seven osteosarcoma tissues and one chondrosarcoma tissue but not with other malignant or benign tumors. Tests of various normal tissues were negative, except for weak binding to a subpopulation of chondrocytes in calcified areas of cartilage near the subchondral bone. Interestingly, none of the antibodies showed reactivity with three osteosarcoma cell lines, Te 85, Te 418, and MG 63. The experiments established the usefulness of the hybridoma technique in preparing monospecific antibodies against human osteosarcoma associated antigens. In particular, this study demonstrates that the use of freshly resected tumor tissues in preparing monoclonal antibodies would provide a necessary tool for the study of tumor associated antigens.