Vaccine compositions comprising endogenous Gag polypeptides

1. A composition comprising: 1) an ARC polypeptide or an endogenous gag (endo-gag) polypeptide; 2) a pathogen-associated antigen; and 3) an adjuvant.

2. The composition of claim 1 , wherein the composition comprises the ARC polypeptide, wherein the ARC polypeptide comprises:

an amino acid sequence that is SEQ ID NO: 1 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 1.

3. The composition of claim 1 , wherein composition comprises the endo-gag polypeptide, wherein the endo-gag polypeptide comprises:

a) an amino acid sequence that is SEQ ID NO: 16 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 16;

b) an amino acid sequence that is SEQ ID NO: 17 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 17;

c) an amino acid sequence that is SEQ ID NO: 18 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 18;

d) an amino acid sequence that is SEQ ID NO: 19 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 19;

e) an amino acid sequence that is SEQ ID NO: 20 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 20;

f) an amino acid sequence that is SEQ ID NO: 21 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 21;

g) an amino acid sequence that is SEQ ID NO: 22 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 22;

h) an amino acid sequence that is SEQ ID NO: 23 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 23;

i) an amino acid sequence that is SEQ ID NO: 24 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 24;

j an amino acid sequence that is SEQ ID NO: 25 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 25;

k) an amino acid sequence that is SEQ ID NO: 26 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 26;

l) an amino acid sequence that is SEQ ID NO: 27 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 27;

m) an amino acid sequence that is SEQ ID NO: 28 or an amino acid sequence that is at least 90% identical to the SEQ ID NO: 28; or

n) any combination thereof.

4. The composition of claim 1 , wherein the pathogen-associated antigen comprises a polypeptide antigen.

5. The composition of claim 1 , wherein the pathogen-associated antigen is a bacterial antigen, a fungal antigen, a parasitic antigen, or a viral antigen.

6. The composition of claim 5 , wherein the composition comprises the viral antigen, wherein the viral antigen is a Coronaviridae antigen.

7. The composition of claim 6 , wherein the viral antigen comprises an amino acid residue sequence as set forth in any one of SEQ ID NOs: 30 to 42, and combinations thereof.

8. The composition of claim 5 , wherein composition comprises the viral antigen, wherein the viral antigen is an Influenza antigen.

9. The composition of claim 1 , wherein the ARC polypeptide or the endo-gag polypeptide is coupled to the pathogen-associated antigen.

10. The composition of claim 9 , wherein the ARC polypeptide or the endo-gag polypeptide is coupled to the pathogen-associated antigen by a peptide bond.

11. The composition of claim 1 , wherein the adjuvant comprises an immune stimulatory compound.

12. The composition of claim 11 , wherein the immune stimulatory compound comprises a lipid, a nucleic acid, an aluminum compound, a water-in-oil emulsion, a polypeptide, or any combination thereof.

13. The composition of claim 1 , wherein the adjuvant is coupled to the ARC polypeptide or the endo-gag polypeptide.

14. The composition of claim 1 , wherein the composition further comprises a virus-like particle.

15. The composition of claim 14 , wherein the virus-like particle comprises: (a) a mixture of the ARC polypeptide or the endo-gag polypeptide coupled to the pathogen-associated antigen; and (b) the ARC polypeptide or the endo-gag polypeptide coupled to the adjuvant.

16. The composition of claim 15 , wherein the virus-like particle further comprises the ARC polypeptide or the endo-gag polypeptide not coupled to the adjuvant or the pathogen-associated antigen.

17. The composition of claim 1 , further comprising a pharmaceutically acceptable excipient, carrier, or diluent.

18. A method of priming an adaptive immune response to a pathogen-associated antigen in an individual comprising administering the composition of claim 1 to the individual, thereby priming the adaptive immune response to the pathogen-associated antigen.

19. The method of claim 18 , wherein the individual is a human individual.

20. The method of claim 18 , wherein the adaptive immune response is an antibody response to the pathogen-associated antigen.

21. The method of claim 20 , wherein the antibody response produces IgG antibodies that specifically bind the pathogen-associated antigen.

22. The method of claim 18 , wherein the adaptive immune response is a cellular immune response to the pathogen-associated antigen.

23. A method of vaccinating an individual comprising administering the composition of claim 1 to the individual, thereby vaccinating the individual.