An attenuated strain of S. typhimurium has been used as a vehicle for oral genetic immunization. Eukaryotic expression vectors containing truncated genes of ActA and listeriolysin--two virulence factors of Listeria monocytogenes--have been used to transform S. typhimurium aroA. Multiple or even single oral immunizations with such transformants induced excellent cellular and humoral responses. I...

Three live vaccine candidates of Salmonella enterica subspecies I serotype Abortusovis (aroA, cya crp cdt, and plasmid-cured strains) have been developed, and their efficacies in inducing humoral antibodies and protecting against abortion after challenge with wild-type strain SS44 were evaluated in sheep. Following estrus synchronization, animals were immunized 3 weeks after fertilization and b...

Bordetella bronchiseptica is an important pathogen causing a number of veterinary respiratory syndromes in agriculturally important and food-producing confinement-reared animals, resulting in great economic losses annually amounting to billions of euros worldwide. Currently available live vaccines are incompletely satisfactory in terms of efficacy and safety. An efficient vaccine for livestock ...

Salmonella typhimurium aroA strains (SL3261), expressing high levels of the Gag protein of feline immunodeficiency virus (FIV) fused with maltose binding protein (SL3261-MFG), were constructed using an invertible promoter system that allows the stable expression of heterologous antigens at levels toxic for bacteria. A SL3261 strain expressing the B subunit of cholera toxin by a similar system (...