Studies on the specificity and sensitivity of the influenza C virus binding assay for 9-O-acetylated sialic acids and its application to human melanomas

The sensitivity and specificity of two influenza C virus assays, solid-phas e and overlay assays, were investigated using naturally occurring 9-O-acety lated GD(3), rat serum glycoproteins containing 60% of N-acetyl-9-O-acetyln euraminic acid, and synthetically O-acetylated sialylated compounds. The se nsitivity of the solid-phase assay was higher for glycoproteins containing N-acetyl-9-O-acetylneuraminic acid than for gangliosides, and also differed for various 9-O-acetylated gangliosides. The overlay assay was less sensit ive for all glycoconjugates tested, For virus recognition the presentation of the sialic acid within the molecule and the structure of the sialic acid are essential. Investigation of gangliosides from human melanomas and norm al skin with the influenza C virus assay showed an increase of O-acetylatio n of sialic acids in most tumour samples and the occurrence of several O-ac etylated gangliosides.