Abstract: The present invention is directed to an attenuated Salmonella comprising a eukaryotic expression vector for delivery of the eukaryotic expression vector to a eukaryotic cell. Delivery may be to eukaryotic cells cultured in vitro or to cells in vivo, such as by oral administration of the attenuated Salmonella comprising the eukaryotic expression vector.

Abstract: An attenuated strain of Salmonella typhimurium has been used as a vehicle for oral genetic immunization. Eukaryotic expression vectors containing the genes for b-galactosidase, or truncated forms of ActA and listeriolysin—two virulence factors of Listeria monocytogenes—that were controlled by an eukaryotic promoter have been used to transform a S. typhimurium aroA strain. Multiple or even single immunizations with these transformants induced a strong cytotoxic and helper T cell response as well as an excellent antibody response. Multiple immunizations with listeriolysin transformants protected the mice completely against a lethal challenge of L. monocytogenes. Partial protection was already observed with a single dose. ActA appeared not to be a protective antigen.