Methods and compositions for pseudoinfectious alphaviruses

1. A pseudoinfectious alphavirus genome encoding: a) alphavirus nonstructural proteins nsP1-4,

b) alphavirus structural proteins E2 and E1, and

c) a Venezuelan equine encephalitis virus (VEEV) capsid protein comprising the amino acid sequence of SEQ ID NO:2 in which two or more amino acids are substituted, resulting in a phenotype of diminished or eliminated packaging of viral genetic material into an alphavirus particle comprising said alphavirus capsid protein, and wherein the amino acid substitutions change two or more positively charged amino acids selected from R16; R23; R24: R29; R53; R54; K64; K65; K67; K68: K73; K75; K81; K82; K83: K84: K88: K89: K90; K92: K99: K105: K106; K107; K110; and/or K111, in any combination, to neutral or negatively charged amino acids.

2. A pseudoinfectious alphavirus particle comprising the pseudoinfectious alphavirus genome of claim 1 .

3. The pseudoinfectious alphavirus particle of claim 2 , wherein the capsid protein comprises a substitution selected from the group consisting of:

1) R16G;

2) R23A;

3) R24N;

4) R29G;

5) R53N;

6) R54N;

7) K64S;

8) K65N;

9) K67G;

10) K68N;

11) K73A;

12) K75N;

13) K81S;

14) K82G;

15) K83N;

16) K84N;

17) K88G;

18) K89G;

19) K9ON;

20) K92S;

21) K99N;

22) K105G;

23) K106N;

24) K107S;

25) K110A;

26) K111S; and

27) any combination of (1) through (26) above.

4. A population of alphavirus particles, comprising the pseudoinfectious alphavirus particle of claim 2 .

5. A pharmaceutical composition comprising the pseudoinfectious alphavirus particle of claim 2 in a pharmaceutically acceptable carrier.

6. A method of eliciting or enhancing an immune response to an alphavirus in a subject, comprising administering to the subject an effective amount of the pseudoinfectious alphavirus particle of claim 2 , thereby eliciting or enhancing an immune response to an alphavirus in the subject.

7. A method of treating and/or inhibiting an alphavirus infection in a subject, comprising administering to the subject an effective amount of the pseudoinfectious alphavirus particle of claim 2 , thereby treating and/or inhibiting an alphavirus infection in the subject.

8. A method of producing pseudoinfectious alphavirus particles in cell culture, comprising introducing into an isolated cell:

a) the pseudoinfectious alphavirus genome of claim 1 ; and

b) a helper nucleic acid molecule encoding alphavirus RNA-binding competent capsid protein; and

maintaining the cell in culture to produce the pseudoinfectious alphavirus particles.

9. A method of producing pseudoinfectious alphavirus particles in cell culture, comprising introducing the pseudoinfectious alphavirus genome of claim 1 into an isolated cell containing a nucleic acid molecule encoding an alphavirus RNA-binding competent capsid protein; and

maintaining the cell in culture to produce the pseudoinfectious alphavirus particles.

10. A population of alphavirus particles comprising the pseudoinfectious alphavirus particles produced by the method of claim 8 .

11. A method of treating and/or inhibiting an alphavirus infection in a subject, comprising administering to the subject an effective amount of the population of pseudoinfectious alphavirus of claim 10 , thereby treating and/or inhibiting an alphavirus infection in the subject.