Altered expression of ganglioside phenotypes of human gliomas in vivo and in vitro.

A library of epitope-defined antiganglioside monoclonal antibodies has been used to analyze the ganglioside phenotype of human glioma cell lines, rodent xenografts derived from them, and a separate panel of human glioma biopsies by multiple quantitative and qualitative assays. We have shown that the ganglioside phenotypes of cultured cell lines differ from the ganglioside phenotypes in the xenografts grown from the parent lines. The lacto series gangliosides 3'-isoLM1 and 3',6'-isoLD1 are expressed in the majority of primary human central nervous system neoplasms and xenografts derived from glioma cell lines, whereas glioma cell lines themselves express 3'-isoLM1 and 3',6'-isoLD1 in only 2/15 and 0/15 cases, respectively. Examination of the ganglioside profiles of serially passaged xenografts established from the glioma cell line D-54 MG, which does not express the lacto series, revealed the appearance of these gangliosides within one to two passages in vivo. The presence of these defined gangliosides in the majority of human gliomas and their absence in normal brain supports their application in compartmental therapy of primary central nervous system tumors.