Ganglioside GM1b as an influenza virus receptor

Receptor activity toward influenza virus A/Aichi/2/68 (H3N2) of a pair of gangliosides, GM1b (NeuAc alpha 2-3 Ga1 beta 1-3 GalNAc beta 1-4 Gal beta 1-4 GLc beta 1-1'-ceramide) and GM1a (Gal beta 1-3 GalNAc beta 1-4 (NeuAc alpha 2-3) Ga1 beta 1-4 Glc beta 1-1'-ceramide) is described. Receptor activity was monitored by an assay system including incorporation of gangliosides into chicken asialoerythrocytes which had lost the biological response for the virus, and subsequent estimation of recovery of virus-mediated haemagglutination and haemolysis. GM1a and GM1b were incorporated in similar amounts into chicken asialoerythrocytes. It was found that GM1b-erythrocytes revealed distinct recovery of influenza virus A/Aichi-mediated agglutination at 4 degrees C and subsequent haemolysis at 37 degrees C at pH 5.3. However, restoration of biological responsiveness of the erythrocytes to the virus by incorporation of GM1a was very low under the same conditions. The above results indicate that the haemagglutinin of the influenza virus A/Aichi/2/68 (H3N2) recognizes the saliosyl residue linked to nonreducing 'terminal' galactose rather than 'inner' galactose in the ganglio-tetraose core of gangliosides. GM1b could be one of the functional receptors to the influenza virus.