Activity of human erythrocyte gangliosides as a receptor to HVJ

Liposomes could bind and fuse efficiently to human erythrocytes in the presence of HVJ when they contained gangliosides isolated from human erythrocytes. Sialosylparagloboside, which has a terminal sequence of NeuAc alpha 2-3Gal beta 1-4GlcNAc, has a much higher receptor activity to the virus than GD1a, GD1b, GT1b, and GT1a, all of which contain the terminal sequence of NeuAc alpha 2-3Gal beta 1-3GalNAc or NeuAc alpha 2-8NeuAc alpha 2-3Gal beta 1-3GalNAc. The activity of sialosylparagloboside is comparable to that of glycophorin, a major sialoglycoprotein of human erythrocytes, when compared on the basis of the required amount (as sialic acid) of compounds. The high affinity of sialosylparagloboside to the viral HANA protein is also suggested by the finding that it showed high inhibitory activity against HVJ-mediated binding of glycophorin liposomes to erythrocytes. Sialosylparagloboside was also highly susceptible to the viral sialidase, the other biological function of HANA protein.