Neuronal cell surface molecules mediate specific binding to rabies virus glycoprotein expressed by a recombinant baculovirus on the surfaces of lepidopteran cells

The existence of specific rabies virus (RV) glycoprotein (G) binding sites on the surfaces of neuroblastoma cells is demonstrated. Spodoptera frugiperda (Sf2l) cells expressing G of the RV strain CVS (Gcvs-Sf21 cells) bind specifically to neuroblastoma cells of different species but not to any other cell type (fibroblast, myoblast, epithelial, or glioma). Attachment to mouse neuroblastoma NG108-15 cells is abolished by previous treatment of Gcvs-Sf21 cells with anti-G antibody. Substitutions for lysine at position 330 and for arginine at position 333 in RV G greatly reduce interaction between Gcvs-Sf2l cells and NG108-15 cells. These data are consistent with in vivo results: an avirulent RV mutant bearing the same double mutation is not able to infect sensory neurons or motoneurons (P. Coulon, J. P. Ternaux, A. Flamand, and C. Tuffereau, J. Virol. 72:273-278, 1998) after intramuscular inoculation into a mouse. Furthermore, infection of NG108-15 cells by RV but not by vesicular stomatitis virus leads to a reduction of the number of binding sites at the neuronal-cell surface. Our data strongly suggest that these specific attachment sites on neuroblastoma cells represent a neuronal receptor(s) used by RV to infect certain types of neurons in vivo.