Rabies virus glycoprotein. II. Biological and serological characterization.

Purified rabies virus glycoprotein (G) was shown by complement fixation and immunodiffusion tests to be a second distinct antigen of the virus. It it the only structural protein of the virus that induces the formation of virus-neutralizing antibodies and which confers immunity to animals. When the G protein is taken as antigen, the complement fixation test can be used for the assay of virus-neutralizing antibodies. The total protective activity of the virus was recovered in the purified G protein preparation. The protective activity of G protein increased with purification: 9 ng of G protein was required to protect 50% of the mice as compared to 1.63 micrograms of the virus. Selective immunofluorescent membrane staining and immunocytolysis of rabies virus-infected cells were shown to be G protein specific. Due to its purity and potency, the G protein preparation can be considered the ideal human antirabies vaccine.