Analysis of the expression of N-glycolylneuraminic acid-containing gangliosides in cells and tissues using two human monoclonal antibodies.

The specificities of two human monoclonal antibodies (2-39M and 32-27M), produced by hybridomas derived from the lymphocytes of melanoma patients (Yamaguchi, H., Furukawa, K., Fortunato, S. R., Livingston, P. O., Lloyd, K. O., Oettgen, H. F., and Old, L. J. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 2416-2420) have been elucidated. Using a large panel of glycolipids, it has been shown that the two monoclonal antibodies (mAbs) identified a number of N-glycolylneuraminic acid (NeuGc)-containing gangliosides. mAb 2-39M reacted with (NeuGc)GM3, (NeuGc)sialylparagloboside, and (NeuGc)sialylhexaglycosylceramide; no reactivity was observed with gangliosides containing only N-acetylneuraminic acid (NeuAc) or with disialogangliosides. These reactive species have the NeuGc alpha 2----3Gal- sequence in common. mAb 32-27M reacted strongly with (NeuGc)2 GD3 and (NeuGc)2disialylparagloboside, and moderately with (NeuAc-NeuGc-)GD3 and (NeuAc-NeuGc-)disialylparagloboside. The reactive species have sialic acid alpha 2----8NeuGc alpha 2----3Gal- sequences in common. These two antibodies were used to demonstrate the species-related presence of different NeuGc-containing gangliosides in various animal erythrocytes by thin layer chromatography immunostaining. No reactivity of either mAb was observed with gangliosides isolated from fresh human colon cancer, melanoma specimens, or some normal tissues, including brain. On the other hand, it was shown that mAb 32-27M reacted with gangliosides isolated from human melanoma and astrocytoma cells grown in fetal bovine serum but not from those grown in synthetic medium. Within the sensitivities of the methods used, these data, and related chemical analyses, do not support the presence of NeuGc-containing gangliosides in human tumors.