Expression vector delivery system and use thereof for inducing an immune response
Embodiments of a novel system for delivering an expression vector encoding an antigen to a subject that allows for spatiotemporal control over stimulation of the subject's immune response to the antigen are provided. In some embodiments, the expression vector delivery system includes a polymer linked to an adjuvant in prodrug form that can form polymer nanoparticles and enter a cell (such as an immune cell) under physiological conditions. In some embodiments, the adjuvant is linked to the polymer by an enzyme degradable labile bond, the cleavage of which activates the adjuvant to stimulate an immune response.
1. A polymer linked to an adjuvant prodrug, wherein:
the polymer linked to the adjuvant prodrug forms polymer nanoparticles that enter immune cells under physiological conditions, and
the adjuvant of the adjuvant prodrug comprises a functional moiety for adjuvant activity that is masked by linkage to a linker connected to the polymer,
the linker comprises an enzyme-degradable labile bond, and
cleavage of the enzyme-degradable labile bond by an intracellular enzyme unmasks the functional moiety and releases an active adjuvant;
wherein the adjuvant prodrug comprises a toll-like receptor 7/8 agonist comprising the structure set forth as one of:
2. The polymer linked to the adjuvant prodrug of claim 1 , wherein the enzyme is a cathepsin.
3. The polymer linked to the adjuvant prodrug of claim 1 , wherein the linker comprises a cathepsin-cleavable peptide comprising L-amino acids or D-amino acids comprising the amino acid sequence set forth as one of: KPLR (SEQ ID NO: 2), KLRP (SEQ ID NO: 3), SLVR (SEQ ID NO: 4), or SLRV (SEQ ID NO: 5), and cathepsin cleavage of the peptide cleaves the labile bond to release the active adjuvant.
4. The polymer linked to the adjuvant prodrug of claim 1 , wherein the polymer linked to the toll-like receptor 7/8 agonist comprises a structure set forth as one of compounds PEI04, PEI05, PEI06, PEI07, PL08, PL09, or PL10.
5. The polymer linked to the adjuvant prodrug of claim 1 , wherein the polymer is a cationic polymer or a hydrophilic polymer.
6. The polymer linked to the adjuvant prodrug of claim 5 , wherein
the cationic polymer is a poly(ethylenimine) polymer, a poly(lysine) polymer, or a poly(arginine) polymer; or
the hydrophilic polymer is a poly(N-(2-hydroxypropyl(methacrylamide))-based co-polymer.
7. The polymer linked to the adjuvant prodrug of claim 1 , wherein the ratio of adjuvant prodrug to monomer of the polymer is from 1:100 to 1:1 mol/mol.
8. The polymer linked to the adjuvant prodrug of claim 1 , wherein the ratio of adjuvant prodrug to monomer of the polymer is from 1:20 to 1:10 mol/mol.
9. The polymer linked to the adjuvant prodrug of claim 1 , wherein the polymer comprises a plurality of monomers comprising from 5 monomers to 500 monomers.
10. The polymer linked to the adjuvant prodrug of claim 1 , wherein the toll-like receptor 7/8 agonist comprises a structure set forth as:
11. An immunogenic composition, comprising
the polymer linked to the adjuvant prodrug of claim 1 ; and
an expression vector comprising a nucleic acid molecule operably linked to a promoter, wherein the nucleic acid molecule encodes an antigen of interest.
12. The immunogenic composition of claim 11 , wherein the expression vector does not comprise any CpG motifs.
13. The immunogenic composition of claim 11 , wherein the expression vector is a plasmid expression vector.
14. The immunogenic composition of claim 11 , wherein the polymer is a cationic polymer and the expression vector is linked to the cationic polymer by an electrostatic interaction.
15. The immunogenic composition of claim 11 , wherein the polymer, the expression vector, and the adjuvant prodrug form polymer nanoparticles in the immunogenic composition.