Rabies virus infection of IMR-32 human neuroblastoma cells and effect of neurochemical and other agents.

IMR-32 human neuroblastoma cells are a continuous nerve cell line expressing neuronal nicotinic acetylcholine receptors. These cells were found to be susceptible to infection by rabies virus (CVS strain). After infection, viral antigen accumulated in the cell body in puncta and larger masses and spread out into the processes until at 3-4 days the entire cell was filled with antigen and lysed. A variety of chemical agents including cholinergic agonists and antagonists were tested for ability to inhibit infection of IMR-32 cells in a fluorescent focus assay. Agents found to inhibit infection were antibodies against the viral glycoprotein, gangliosides, a synthetic peptide of the neurotoxin-binding site of Torpedo acetylcholine receptor alpha1 subunit, alpha-bungarotoxin, and lysosomotropic agents. All other agents tested including other cholinergic ligands and synthetic peptides were not effective. Except for lysosomotropic agents, the agents which inhibited infection also inhibited attachment of virus to the cell surface. These results indicate that IMR-32 cells are a useful model in studying the interaction of a neurotropic virus with human neurons. The ability of alpha-bungarotoxin to inhibit infection suggests that neuronal alpha-bungarotoxin-binding receptors might serve as central nervous system receptors for rabies virus.