Stable pura vectors and uses therefor
AssigneePraxis Biologics, Inc.
InventorsRobert N. Brey, James P. Fulginiti, Algis Anilionis
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Abstract
This invention pertains to a complementation system for the selection and maintenance of expressed genes in bacterial hosts. The invention provides stable vectors which can be selected and maintained by complementation of chromosomal deletion mutations of purA (adenylosuccinate synthetase), obviating the use of antibiotic resistance genes. This system is useful in production organisms during fermentation and in live vaccine bacteria, such as attenuated Salmonella typhi. This system allows for selection of chromosomal integrants and for selection and stable plasmid maintenance in the vaccinated host without application of external selection pressure.
Claims32
A method of eliciting an immune response against an antigen, comprising administering to a warm-blooded host, an immunologically effective dose of a composition comprising a purA attenuated bacterium which harbors a stable plasmid which does not contain an antibiotic resistance determinant and which contains a heterologous purA gene encoding adenylosuccinate synthetase and a nucleotide sequence encoding at least one antigen or fragment thereof, in a pharmaceutically acceptable vehicle and an optional adjuvant.
An immunogenic composition comprising a purA bacterium which harbors a stable plasmid which does not contain an antibiotic resistance determinant and which contains a heterologous purA gene encoding adenylosuccinate synthetase and a nucleotide sequence encoding at least one antigen or fragment thereof, in a physiologically acceptable vehicle and optional adjuvant.
Dependencies are inferred from the claim text.