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.
1. An attenuated Salmonella strain comprising a eukaryotic expression vector, wherein said vector comprises a eukaryotic promoter and a heterologous DNA encoding a heterologous polypeptide, wherein said DNA is under the control of said eukaryotic promoter, wherein the attenuation is suitable for administration to a vertebrate, and wherein said administration to said vertebrate of said attenuated Salmonella strain results in expression of said polypeptide by said vertebrate and generates an immune response by said vertebrate to said polypeptide.
2. The Salmonella strain of claim 1 , wherein the strain is a S. typhimurium strain.
3. The S. typhimurium strain of claim 2 , wherein the strain is selected from the group consisting of S. typhimurium aroA SL 7207, S. typhimurium LT2, and S. typhimurium aroA544 (ATCC Accession No. 33275).
4. The Salmonella strain of claim 1 , wherein the strain is a S. typhi strain.
5. The S. typhi strain of claim 4 , wherein the strain is S. typhi Ty21a.
6. The Salmonella strain of claim 1 , wherein the eukaryotic expression vector comprises:
a) a structural gene of β-galactosidase (β-gal) under the control of a human cytomegalovirus (CMV) immediate early promoter,
b) a splice donor,
c) two splice acceptor sites between the promoter and the β-galactosidase gene, and
d) a polyadenylation site of SV40.
7. The Salmonella strain of claim 1 , wherein the polypeptide is selected from the group consisting of an Escherichia coli β-galactosidase, a non-hemolytic truncated Listeria monocytogenes listeriolysin, and a truncated Listeria monocytogenes actA polypeptide.
8. A vaccine comprising the Salmonella strain of claim 1 .
9. The Salmonella strain of claim 1 , wherein the encoded polypeptide is capable of inducing an antibody response and a T-cell response, wherein the T-cell response comprises production of CD8 T-cells and CD4 T-cells.
10. The Salmonella strain of claim 1 , wherein the encoded polypeptide is capable of inducing an antibody response and a T-cell response, wherein the antibody response comprises production of IgG1, IgG2, and IgA antibodies.
11. The Salmonella strain of claim 1 , wherein the vertebrate is a human.
12. The Salmonella strain of claim 1 , wherein the Salmonella strain is orally administered.
13. The Salmonella strain of claim 10 , wherein the antibody response is induced after a single immunization.
14. The Salmonella strain of claim 9 , wherein the T-cell response is induced after a single immunization.
15. The Salmonella strain of claim 7 , wherein the polypeptide is a non-hemolytic truncated Listeria monocytogenes listeriolysin polypeptide.