Modified free-living microbes, vaccine compositions and methods of use thereof
Free-living microbes are provided in which the nucleic acid has been modified so that the microbe is attenuated for proliferation and/or which comprise genetic mutations that attenuate the ability of the microbe to repair its nucleic acid. Methods of using the modified microbes for the loading, activation, and/or maturation of antigen-presenting cells are also provided. Vaccine compositions comprising the modified microbes and/or the antigen-presenting cells and methods of using the vaccines are also provided. The microbes may be further modified to include heterologous antigens, such as tumor antigens or infectious disease antigens, for use as a vaccine against cancer or infectious diseases.
1. A composition comprising modified bacteria, the genomic DNA of said modified bacteria comprising:
(i) interstrand crosslinks introduced between the strands of genomic DNA double helix, said interstrand crosslinks inhibiting replication of said modified bacteria, (ii) one or more genetic mutations in uvr gene(s), said mutation(s) inhibiting excision repair of said interstrand crosslinks, and (iii) a nucleic acid sequence encoding a heterologous polypeptide operably linked to a promoter sequence directing expression of the heterologous polypeptide by the modified bacteria; and
a pharmaceutically acceptable excipient.
2. The composition of claim 1 , wherein the composition is in a formulation suitable for oral delivery.
3. The composition of claim 1 , wherein the composition is in a formulation suitable for nasal delivery.
4. The composition of claim 2 , wherein the formulation is a solid formulation comprising a solid-based dry material.
5. The composition of claim 2 , wherein said formulation is in the form of a liquid.
6. The composition of claim 1 , wherein the genetic mutations in uvr gene(s) comprise deletions in the uvrA and uvrB genes such that the modified bacteria do not produce functional uvrA and uvrB gene products.
7. The composition of claim 1 , wherein the bacteria are selected from Salmonella, Shigella sp., Mycobacterium tuberculosis, E. coli, Neisseria meningitides, Brucella abortus, Brucella melitensis, Borrelia burgdorferi , and Francisella tularensis.
8. A method of inducing an immune response to an antigen in a mammalian subject, the method comprising administering to an individual a composition according to claim 1 , wherein said heterologous polypeptide comprises said antigen.
9. The method of claim 8 , wherein said composition is orally administered.
10. The method of claim 8 , wherein said composition is nasally administered.
11. The composition of claim 1 , wherein the modified bacteria are Listeria monocytogenes bacteria.
12. The composition of claim 11 , wherein the genetic mutations in uvr gene(s) comprise deletions in the uvrA and uvrB genes such that the Listeria monocytogenes bacteria do not produce functional uvrA and uvrB gene products.
13. The method of claim 8 , wherein said composition is administered intravenously.
14. The method of claim 8 , wherein said composition is administered intraperitoneally.
15. The method of claim 8 , wherein said composition is administered intramuscularly.
16. The method of claim 8 , wherein said composition is administered subcutaneously.
17. The composition of claim 1 , wherein the heterologous polypeptide comprises a polypeptide sequence from a virus selected from the group consisting of human immunodeficiency virus, feline immunodeficiency virus, herpes simplex virus, cytomegalovirus, human metapneumovirus, Epstein-Barr virus, varicella zoster virus, hepatitis B virus, hepatitis A virus, hepatitis C virus, delta hepatitis virus, hepatitis E virus, and hepatitis G virus.
18. The composition of claim 1 , wherein the heterologous polypeptide comprises a polypeptide sequence from a bacterial species selected from the group consisting of Mycobacterium, Bacillus, Yersinia, Salmonella, Neisseria, Borrelia, Chlamydia , and Bordetella.
19. The composition of claim 1 , wherein the heterologous polypeptide comprises a polypeptide sequence from a parasite species selected from the group consisting of Plasmodium and Toxoplasma.