Bacterial RNAs as vaccine adjuvants
The invention features vaccine adjuvants comprising prokaryotic mRNA, and methods of vaccination using the adjuvants.
1. A vaccine composition comprising a tumor antigen and an adjuvant, wherein said adjuvant comprises prokaryotic mRNA, wherein the prokaryotic mRNA has structural features comprising a 3′ stem loop structure, intramolecular base-pairing, and no 3′ poly(A) tail.
2. The composition of claim 1 , wherein the tumor antigen is carried by a cell.
3. The composition of claim 2 , wherein the prokaryotic mRNA is contained in the cell.
4. A vaccine composition comprising an immunogenic peptide of microbial or mammalian origin and an adjuvant, wherein said adjuvant comprises prokaryotic mRNA, wherein the prokaryotic mRNA has structural features comprising a 3′ stem loop structure, intramolecular base-pairing, and no 3′ poly(A) tail.
5. The composition of claim 4 , wherein the immunogenic peptide is carried by a cell.
6. The composition of claim 5 , wherein the prokaryotic mRNA is contained in the cell.
7. The composition of claim 1 , wherein the mRNA has no 5′ tri-phosphate group.
8. The composition of claim 1 , wherein the mRNA contains nucleotide modifications.
9. A method of eliciting an immune response in a subject, comprising administering to the subject the composition of claim 1 .
10. The method of claim 9 , wherein the subject is human.
11. The method of claim 9 , wherein the immune response protects the subject from developing a cancer, or treats a subject in need of cancer immunotherapy.
12. The method of claim 9 , wherein the immune response comprises one or more of the following: IL-1β production, IFN-β production, increased IgG isotype levels, increased primary and secondary T cell responses, and death of infected cells.
13. A method of inducing IFN-β or IL-1β production in immune cells, comprising contacting the cells with the composition of claim 1 .
14. A method of preparing a vaccine composition of claim 1 , comprising mixing a tumor antigen with prokaryotic mRNA.
15. An immunization kit, comprising a vaccine composition comprising a tumor antigen, and an adjuvant composition comprising prokaryotic mRNA, wherein the prokaryotic mRNA has structural features comprising a 3′ stem loop structure, intramolecular base-pairing, and no 3′ poly(A) tail.
16. The composition of claim 1 , wherein the vaccine further comprises a second adjuvant.
17. The composition of claim 16 , wherein the second adjuvant is lipopolysaccharide.
18. The composition of claim 16 , wherein the second adjuvant is monophosphoryl lipid A.