Development of a Genetically–Engineered, Candidate Polio Vaccine Employing the Self–Assembling Properties of the Tobacco Mosaic Virus Coat Protein

A synthetic gene coding for the coat protein of tobacco mosaic virus (TMVCP) was expressed in E. coli under the direction of the lacUV5 promoter. Modification of the 3′ end of the TMVCP gene by insertion of a region coding for an antigenic epitope from poliovirus type 3 resulted in the production of a hybrid TMVCP (TMVCP–polio 3). Both the E. coli–produced TMVCP and TMVCP–polio 3 were shown to assemble into virus–like rods under acidic conditions in E. coli extracts. Their purification was accomplished in a single step by chromatography on Sepharose 6B. TMVCP–polio 3 induced the formation of poliovirus neutralizing antibodies following injection into rats. The level of immune response was related to the degree of polymerization of the TMVCP–polio 3 preparations.