1994 Volume 116 Issue 1 Pages 64-73
In this study gangliosides from various myelomas and hybridomas of mouse, rat, and human origin were characterized by thin-layer and high-performance liquid chromatography, immunological methods (overlay technique) and fast atom bombardment mass spectrometry. Exclusively GM3 substituted with C24:1- and C16:0-fatty acid, was found in all B cell-derived cell lines. C18 sphingosine was the single long chain base in each GM3 ceramide portion. The mouse myeloma (NS-1) and all hybridomas, obtained by fusion of mouse, rat, or human B lymphocytes with murine myelomas, showed high GM3 (NeuGc) content (>75%) and low GM3(NeuAc) expression. Absolute amounts of GM3 ranged from 0.2 up to 0.8mg×10-9 cells. Normally, human cells do not express NeuGc, and an Epstein-Barr virus-transformed human B lymphocyte line analyzed in this study retained this sialylation status, expressing exclusively GM3(NeuAc) (100%). The fusion of human B lymphocytes with mouse myelomas led to high GM3(NeuGc) expression (average about 85%) in all mouse/human heterohybridomas examined. Our results indicate the chromosomal gene “transfer” and/or the activation of enzymes involved in NeuGc-biosynthesis due to the somatic cell fusion process, which might explain the mouse dominance in the manifestation of the NeuGc-phenotype in hybridomas of human origin.
