CHARACTERIZATION OF HUMAN IGG1 MONOCLONAL-ANTIBODY AGAINST GANGLIOSIDES EXPRESSED ON TUMOR-CELLS

A human IgG1.k monoclonal antibody (MAb) designated GMA1 was developed by fusing pooled lymph node lymphocytes from cancer patients with the human lymphoblastoid cell line, SHFP-1, The GMA1 MAb reacted with sev eral melanoma and neuroblastoma cell lines. Normal tissue derived from human brain and tumor-cell lines derived from colon, ovary, and breas t were not reactive, FAGS analysis performed using live cells demonstr ated that the antibody recognizes a cell-surface antigen. Enzyme immun oassay (EIA) and thin layer chromatography (TLC) immunostaining with p urified gangliosides indicated that the antibody has specificity for t he major tumor associated gangliosides GD3, GM3, and GD2, GMA1 heavy a nd light chain genes were isolated by RT-PCR and a recombinant derivat ive of this human antibody was expressed in Chinese hamster ovary (CHO ) cells. High-level antibody synthesis and secretion was achieved usin g a vector designed to maximize expression. FAGS analysis and TLC immu nostaining indicated recombinant GMA1 reacted with human tumor cell li nes and gangliosides GD3, GM3, GD2 in a manner similar to the antibody produced by the hybridoma cell line, demonstrating that the specifici ty of the antibody was not altered during molecular cloning.