MONOCLONAL-ANTIBODY AGAINST A LACTOSE EPITOPE OF GLYCOSPHINGOLIPIDS BINDS TO MELANOMA TUMOR-CELLS

Mice were immunized with a neoglycoprotein consisting of a chemically modified carbohydrate moiety (reductively aminated 3'-sialyllactose) l inked to human serum albumin. By this procedure an antibody response t o the normally non-immunogenic carbohydrate structure was obtained. Hy bridomas were established, and monoclonal antibodies were selected in ELISA based on their binding to the saccharide hapten, or to a lactosy lceramide-mimicking neoglycolipid, lactose-bis-sulfone. One of the sel ected antibodies, 2H4, was of particular interest, since it also bound to glycolipids present on melanoma cells. FACS analysis of a panel of 14 melanoma cell lines showed that the 2H4 antibody bound to the majo rity of these. In frozen, non-fixed sections or paraffin sections of b iopsies the monoclonal antibody 2H4 stained melanoma cells, but not tu mour infiltrating lymphocytes or normal skin. Detailed immunochemical analysis of 2H4, using thin layer chromatography revealed that it reco gnized an internal lactose epitope in several glycosphingolipids.