Virus-like particles and methods of use

1. An alphavirus virus-like particle (VLP) comprising at least one altered viral protein selected from the group consisting of:

a. an alphavirus E2 protein comprising one or more alterations, relative to the wild-type amino acid sequence, at one or more amino acid locations corresponding to one or more amino acid locations selected from the group consisting of H170, K200, K233, K234, R251 and H256 of CHKV E2 protein; and

b. an alphavirus capsid protein comprising one or more alterations, relative to the wild-type amino acid sequence, at a charged amino acid residue in the Nuclear Localization Signal (NLS);

wherein the at least one altered viral protein is capable of self-assembling into a VLP; and wherein the one or more alterations enhance VLP production.

2. The VLP of claim 1 , wherein the one or more altered viral protein(s) are derived from a virus selected from the group consisting of Eastern equine encephalitis virus (EEEV), Western equine encephalitis virus (WEEV), Venezuelan equine encephalitis virus (VEEV), Semliki Forest virus (SFV), Chikungunya virus (CHIKV), O'nyong-nyong virus, Sindbis virus, Mayaro virus, Ross River virus, Barmah Forest virus, and Ockelbo virus.

3. The VLP of claim 1 , wherein the one or more alteration in a charged amino acid residue in the NLS is in at least one amino acid region selected from the group consisting of:

a. amino acids 67-70 of an EEEV capsid protein;

b. amino acids 67-70 of an WEEV capsid protein;

c. amino acids 64-68 of an VEEV capsid protein;

d. amino acids 62-69 of a CHIKV capsid protein;

e. amino acids 71-74 of a Ross River virus capsid protein; and

f. amino acids 64-68 of a Barmah Forest virus capsid protein.

4. The VLP of claim 1 , wherein the VLP comprises an agent to be introduced to a cell.

5. A method of inducing an immune response against an alphavirus in a subject, comprising administering to the subject an effective amount of the VLP of claim 1 .

6. A pan-viral immunogenic composition comprising:

a. the VLP of claim 1 ; and

b. a second alphavirus VLP comprising at least one altered viral protein selected from the group consisting of:

i. an alphavirus E2 protein comprising one or more alterations, relative to the wild-type sequence, at one or more amino acid locations corresponding to one or more amino acid locations selected from the group consisting of H170, H200, K233, K234, R251 and H256 of CHKV E2 protein; and

ii. an alphavirus capsid protein comprising one or more alterations, relative to the wild-type sequence, at a charged amino acid residue in the Nuclear Localization Signal (NLS);

wherein the at least one altered viral protein is capable of self-assembling into a VLP;

wherein the one or more alterations enhance VLP production, and wherein the altered viral proteins of the VLP of claim 1 and the second VLP are from different alphaviruses.

7. A kit comprising the VLP of claim 1 .

8. A method of introducing an agent into a cell comprising:

a. packaging the agent into an alphavirus VLP comprising at least one altered viral proteins selected from the group consisting of:

i. an alphavirus E2 protein comprising one or more alterations, relative to the wild-type amino acid sequence, at one or more amino acid location corresponding to one or more amino acid location selected from the group consisting of H170, K200, K233, K234, R251 and H256 of CHKV E2 protein; and

ii. an alphavirus capsid protein comprising one or more alterations, relative to the wild-type amino acid sequence, at a charged amino acid residue in the Nuclear Localization Signal (NLS);

wherein the at least one altered viral protein is capable of self-assembling into a VLP; and wherein the one or more alterations enhance VLP production;

b. contacting a cell with the VLP under conditions that allow the VLP to enter the cell, thereby introducing the agent into the cell.

9. The method of claim 8 , wherein the one or more altered viral protein(s) are derived from a virus selected from the group consisting of Eastern equine encephalitis virus (EEEV), Western equine encephalitis virus (WEEV), Venezuelan equine encephalitis virus (VEEV), Semliki Forest virus (SFV), Chikungunya virus (CHIKV), O'nyong-nyong virus, Sindbis virus, Mayaro virus, Ross River virus, Barmah Forest virus, and Ockelbo virus.

10. The method of claim 8 , wherein the one or more alteration in a charged amino acid residue in the NLS is in at least one amino acid region selected from the group consisting of:

a. amino acids 67-70 of an EEEV capsid protein;

b. amino acids 67-70 of an WEEV capsid protein;

c. amino acids 64-68 of an VEEV capsid protein;

d. amino acids 62-69 of a CHIKV capsid protein;

e. amino acids 71-74 of a Ross River virus capsid protein; and

f. amino acids 64-68 of a Barmah Forest virus capsid protein.

11. The VLP of claim 1 , wherein the E2 protein comprising one or more alterations comprises an amino acid sequence selected from the group consisting of:

a) an amino acid sequence selected from the group consisting of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:68, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, wherein the amino acid at a position corresponding to position 170 of SEQ ID NO:65 is not a histidine;

b) an amino acid sequence selected from the group consisting of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:68, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, wherein the amino acid at a position corresponding to position 200 of SEQ ID NO:65 has been modified;

c) an amino acid sequence selected from the group consisting of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:68, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, wherein the amino acid at a position corresponding to position 233 of SEQ ID NO:65 has been modified;

d) an amino acid sequence selected from the group consisting of consisting of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:68, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, wherein the amino acid at a position corresponding to position 234 of SEQ ID NO:65 is not a lysine;

e) an amino acid sequence consisting of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:68, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, wherein the amino acid at a position corresponding to position 251 of SEQ ID NO:65 has been modified; and,

f) an amino acid sequence selected from the group consisting of SEQ ID NO:65, SEQ ID NO:66, SEQ ID NO:67, SEQ ID NO:68, SEQ ID NO:69, SEQ ID NO:70 and SEQ ID NO:71, wherein the amino acid at a position corresponding to position 256 of SEQ ID NO:65 is not a histidine;

wherein the E2 protein comprising one or more alterations can form a VLP.

12. The VLP of claim 11 , wherein the wherein the amino acid at a position corresponding to position 234 of SEQ ID NO:65 is an asparagine.

13. The VLP of claim 1 , wherein the capsid protein comprises an amino acid sequence selected from the group consisting of:

a) an amino acid sequence comprising SEQ ID NO:115 (WEEV), wherein the amino acid sequence is altered at one or more amino acid positions selected from the group consisting of amino acid position 67, amino acid position 68 and amino acid position 69;

b) an amino acid sequence comprising SEQ ID NO:124 (VEEV), wherein the amino acid sequence is altered at amino acid position 67;

c) an amino acid sequence comprising SEQ ID NO:142 (CHIKV), wherein the amino acid sequence is altered at one or more amino acid positions selected from the group consisting of amino acid position 62, amino acid position 63, amino acid position 65, amino acid position 66, amino acid position 68 and amino acid position 69;

d) an amino acid sequence comprising SEQ ID NO:154 (Ross River), wherein the amino acid sequence is altered at one or more amino acid positions selected from the group consisting of amino acid position 71, amino acid position 72, amino acid position 73 and amino acid position 74;

e) an amino acid sequence comprising SEQ ID NO:171 (BFV), wherein the amino acid sequence is altered at one or more amino acid position selected from the group consisting of amino acid position 64, amino acid position 65, amino acid position 67 and amino acid position 68.

14. The VLP of claim 1 , wherein the capsid protein comprises an amino acid sequence selected from the group consisting of:

a) an amino acid sequence comprising SEQ ID NO:115 (WEEV), wherein the amino acid sequence comprises one or more alterations selected from the group consisting of K67N, K68N and K69N;

b) an amino acid sequence comprising SEQ ID NO:124 (VEEV), wherein the amino acid sequence comprises one or more alterations selected from the group consisting of K64N, K65A, K65N, K67A and K67N;

c) an amino acid sequence comprising SEQ ID NO:142 (CHIKV), wherein the amino acid sequence comprises one or more alterations selected from the group consisting of R62A, R63A, R65A, K66A, K68A and K69A;

d) an amino acid sequence comprising SEQ ID NO:154 (Ross River), wherein the amino acid sequence comprises one or more alterations selected from the group consisting of R71N, K72N, K73N and K74N; and,

e) an amino acid sequence comprising SEQ ID NO:171 (BFV), wherein the amino acid sequence comprises one or more alterations selected from the group consisting of K64A, K64N, K65A, K65N, K67A, K67N, K68A and K68N.

15. The VLP of claim 1 , wherein the capsid protein comprises an amino acid sequence selected from the group consisting of SEQ ID NO:115, SEQ ID NO:118, SEQ ID NO:121, SEQ ID NO:124, SEQ ID NO:127, SEQ ID NO:130, SEQ ID NO:133, SEQ ID NO:136, SEQ ID NO:139, SEQ ID NO:142, SEQ ID NO:145, SEQ ID NO:148, SEQ ID NO:151, SEQ ID NO:154, SEQ ID NO:157, SEQ ID NO:160, SEQ ID NO:163 and SEQ ID NO:171.

16. The VLP of claim 11 , wherein the wherein the amino acid at a position corresponding to position 170 of SEQ ID NO:65 is a methionine.

17. The VLP of claim 11 , wherein the wherein the amino acid at a position corresponding to position 200 of SEQ ID NO:65 is a lysine.

18. The VLP of claim 11 , wherein the wherein the amino acid at a position corresponding to position 233 of SEQ ID NO:65 is an asparagine.

19. The VLP of claim 11 , wherein the wherein the amino acid at a position corresponding to position 256 of SEQ ID NO:65 is a glutamine.