Abstract
A new monoclonal antibody (NS24) directed to the N-acetylneuraminylα2-3Ga1β1- 4G1cNAc residue in type II sugar chain of N-acetylneuraminyllactoneotetraosylceramide [sialylparagloboside, IV3(NeuAc)nLc4Cer] was prepared by hybridoma technique. Lipo-somes composed of dipalmitoylphosphatidylcholine, cholesterol, IV3 (NeuAc) nLc4Cer, and lipopolysaccharides from Salmonella minnesota R595 were used for immunization with IV3 (NeuAc) nLc4Cer isolated from human erythrocytes. This method allowed the fusion of spleen cells of immunized mouse with myeloma cells only three days after immunization. NS24 reacted specifically to both naturally occurring and chemically synthesized IV3-(NeuAc)nLc4Cer, whereas it has no reactivity to structurally related gangliosides, such as IV6(NeuAc)nLc4Cer, N-glycolylneuraminyl α2-3 1actoneotetraosylceramide [IV3(NeuGc)-nLc4Cer], i-active ganglioside [VI3 (NeuAc) nLc6Cer], I-active ganglioside [VIII3 (NeuAc)-VP(NeuAc)IV6kladoLc8Cer], GM4 (NeuAc), GM3 (NeuAc), GM3(NeuGc), GM1b(NeuAc), GD3-(NeuAc), other ganglio-series gangliosides, sulfatide, and paragloboside (nLc4Cer). Syn-thetic N-acetylneuraminylα2-3lactotetraosylceramide [IV3 (NeuAc) Lc4Cer] and its asi-alo-derivative (Lc4Cer) carrying type I sugar chain also showed no reaction with NS24. One to 100 pmol of IV3 (NeuAc) nLc4Cer was detected dose-dependently by a thin-layer chro-matography/enzyme immunostaining procedure. Human gastric carcinomas showed positive reactions with NS24 immunochemically and histochemically. NS24 reacted preferentially with poorly differentiated adenocarcinomas rather than well differentiated ones.
