Inhibition of rabies virus in vitro by the ammonium-5-tungsto-2-antimoniate.

In vitro multiplication of rabies virus was inhibited by a condensed mineral ion, ammonium-5-tungsto-2-antimoniate (HPA 23). The inhibitory effect was evaluated by two different methods, plaque reduction and one step virus growth. Plaquing showed 50% inhibition with 4.5 microgram/ml of HPA 23 and complete inhibition with 12.5 microgram/ml. A reduction of two logs in virus yield was obtained in BHK21C13S cells in suspension treated with 50 microgram/ml of HPA 23. Inhibition also occurred when treatment with HPA 23 was started 18 to 24 h after infection in the plaque assay but no effect was seen when HPA 23 was added 48 h after virus inoculation. All these inhibitory effects of HPA 23 on rabies virus multiplication were observed at non cytotoxic doses. Therefore HPA 23 contrasts with other antiviral drugs which do not inhibit rabies virus multiplication without affecting the viability of cells.