Absence of myelin basic protein in an improved purified duck embryo rabies vaccine

The encephalitogenic potential of rabies vaccines prepared from nervous tissue is a result of the presence of myelin basic protein. Vaccines prepared from duck embryos are economical and efficient, but, occasionally, cases of allergic encephalomyelitis have been reported. An improved rabies vaccine has been developed that contains the classical Pitman Moore strain of rabies virus grown in embryonated duck eggs. This vaccine has been highly purified and enriched in immunologically effective rabies virus glycoprotein antigen. We have searched for the presence of myelin basic protein using sensitive radioimmunological and immunoblotting techniques. Whereas the classical duck embryo rabies vaccine contained small amounts of myelin basic protein, in the improved purified duck embryo rabies vaccine, none could be detected.