Virus like particle comprising PD-1 antigen or PD-1 ligand antigen

1. A virus-like particle comprising a virus structural protein and an antigen selected from the group consisting of (a)-(c):

(a) an antigen which comprises a 10-300 amino acid fragment of human Programmed Death-1 (PD-1), or which comprises an amino acid sequence having at least 90% amino acid identity to said fragment of human PD-1;

(b) an antigen which comprises a 10-300 amino acid fragment of human Programmed Death-Ligand 1 (PD-L1), or which comprises an amino acid sequence having at least 90% amino acid identity to said fragment of human PD-L1; and

(c) an antigen which comprises a 10-300 amino acid fragment of human Programmed Death-Ligand 2 (PD-L2), or which comprises an amino acid sequence having at least 90% amino acid identity to said fragment of human PD-L2.

2. The virus-like particle according to claim 1 , wherein the virus structural protein is an alphavirus or flavivirus polypeptide.

3. The virus-like particle according to claim 1 , wherein the virus structural protein is a Chikungunya virus or Venezuelan equine encephalitis virus polypeptide.

4. The virus-like particle according to claim 1 , wherein the virus structural protein comprises at least one protein selected from the group consisting of: a capsid protein, an E1 envelope protein, and an E2 envelope protein.

5. The virus-like particle according to claim 4 , wherein said virus-like particle comprises an E2 envelope protein, and wherein said antigen is inserted into said E2 envelope protein.

6. The virus-like particle according to claim 1 , wherein the virus-like particle contains capsid protein, envelope protein E1, and envelope protein E2 in which said antigen is inserted,

wherein said envelope protein E2 into which the antigen is inserted consists of an amino acid sequence with at least 90% amino acid sequence identity to a sequence selected from the group consisting of SEQ ID NOs: 33-35,

wherein said envelope protein E1 consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 37,

and wherein said capsid protein consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 38.

7. The virus-like particle according to claim 1 , wherein the virus-like particle contains capsid protein, envelope protein E1, and envelope protein E2 in which said antigen is inserted,

wherein said envelope protein E2 into which the antigen is inserted consists of an amino acid sequence with at least 90% amino acid sequence identity to a sequence selected from the group consisting of SEQ ID NOs: 39-41,

wherein said envelope protein E1 consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 43,

and wherein said capsid protein consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 44.

8. The virus-like particle according to claim 1 , wherein the virus-like particle contains capsid protein, envelope protein E1, and envelope protein E2 in which said antigen is inserted,

wherein said envelope protein E2 into which the antigen is inserted consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 36,

wherein said envelope protein E1 consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 37,

and wherein said capsid protein consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 38.

9. The virus-like particle according to claim 1 , wherein the virus-like particle contains capsid protein, envelope protein E1, and envelope protein E2 in which said antigen is inserted,

wherein said envelope protein E2 into which the antigen is inserted consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 42,

wherein said envelope protein E1 consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 43,

and wherein said capsid protein consists of an amino acid sequence with at least 90% amino acid sequence identity to SEQ ID NO: 44.

10. An isolated nucleic acid molecule comprising a nucleotide sequence that encodes the entire virus-like particle according to claim 1 .

11. A vector comprising the nucleic acid molecule according to claim 10 , wherein the vector optionally comprises an expression control sequence operably linked to the nucleic acid molecule.

12. A pharmaceutical composition comprising:

(a) the virus-like particle according to claim 1 ; and

(b) a pharmaceutically acceptable carrier.

13. A vaccine composition comprising:

(a) the virus-like particle according to claim 1 , and

(b) a pharmaceutically acceptable carrier.

14. A method for treating or preventing cancer or infectious disease; producing an antibody against PD-1 or a ligand of PD-1 in a mammal; modulating an immune response; immunostimulation; inhibiting an interaction between PD-1 and a ligand of PD-1; or inhibiting a PD-1 activity, comprising administering the virus-like particle according to claim 1 to a subject in need thereof.

15. A kit comprising:

(a) a pharmaceutical composition comprising the virus-like particle according to claim 1 ; and

(b) another pharmaceutical composition comprising the virus-like particle according to claim 1 ,

wherein the virus-like particle contained in (a) is a virus-like particle which is different from the virus-like particle contained in (b).

16. The kit according to claim 15 , wherein the virus-like particle contained in (a) is a Chikungunya virus-like particle, and the virus-like particle contained in (b) is a Venezuelan equine encephalitis virus-like particle; or wherein the virus-like particle contained in (a) is a Venezuelan equine encephalitis virus-like particle, and the virus-like particle contained in (b) is a Chikungunya virus-like particle.

17. The virus-like particle according to claim 6 , wherein said envelope protein E2 into which the antigen is inserted consists of an amino acid sequence selected from the group consisting of SEQ ID NOs: 33-35,

wherein said envelope protein E1 consists of the amino acid sequence of SEQ ID NO: 37,

and wherein said capsid protein consists of the amino acid sequence of SEQ ID NO: 38.