Live oral vaccines using salmonella

Abstract

The first attenuated Salmonella strains were developed some years ago in order to be used as live oral candidate vaccines against typhoid fever. In the beginning, the mutations responsible for the attenuated phenotype were unknown, however, with the accumulation of knowledge about the genetics of virulence, new genetically defined attenuated strains became available. Many strains of S. enterica serovar Typhimurium and S. enterica serovar Typhi were carefully studied concerning their ability to induce immune response in humans and animals. As the use of vaccine strains has expanded with the development of efficient cloning and expressing systems, the production and delivery of antigens from different pathogens have become more and more available. Lately, the use of Salmonella as the DNA carrier has been one of the most promising technologies as far as DNA vaccines are concerned. All this progress in the studies with the Salmonella vaccine strains shows their potential for new vaccines production against infectious disease, parasitic disease and even against cancer, in a near future.