Stabilized soluble pre-fusion RSV F polypeptides

1. A recombinant pre-fusion respiratory syncytial virus (RSV) Fusion (F) mutant polypeptide, comprising

a mutation of the amino acid residue N/T at position 67 into I and/or a mutation of the amino acid residue S at position 215 into P, wherein the amino acid positions are given in reference to the sequence of RSV F protein from the A2 strain (SEQ ID NO: 1).

2. The pre-fusion RSV F mutant polypeptide according to claim 1 , wherein the mutant polypeptide comprises an F1 domain and an F2 domain, and a linking sequence comprising from 1 to 10 amino acid residues, linking said F1 domain to said F2 domain.

3. The pre-fusion RSV F mutant polypeptide of claim 1 , comprising a truncated F1 domain and an F2 domain, and a linking sequence comprising 1 to 10 amino acid residues, linking said F1 domain to said F2 domain.

4. The pre-fusion RSV F mutant polypeptide according to claim 3 , wherein the mutant polypeptide comprises a heterologous trimerization domain linked to said truncated F1 domain.

5. The pre-fusion RSV F mutant polypeptide of claim 1 , wherein the mutant polypeptide comprises at least one further mutation, wherein said mutation is selected from the group consisting of:

(a) a mutation of the amino acid residue on position 46;

(b) a mutation of the amino acid residue on position 77;

(c) a mutation of the amino acid residue on position 80;

(d) a mutation of the amino acid residue on position 92;

(e) a mutation of the amino acid residue on position 175;

(f) a mutation of the amino acid residue on position 184;

(g) a mutation of the amino acid residue on position 185;

(h) a mutation of the amino acid residue on position 201;

(i) a mutation of the amino acid residue on position 209;

(j) a mutation of the amino acid residue on position 421;

(k) a mutation of the amino acid residue on position 426;

(l) a mutation of the amino acid residue on position 465;

(m) a mutation of the amino acid residue on position 486;

(n) a mutation of the amino acid residue on position 487; and

(o) a mutation of the amino acid residue on position 508.

6. The pre-fusion RSV F mutant polypeptide according to claim 5 , wherein the at least one further mutation is selected from the group consisting of:

(a) a mutation of the amino acid residue S on position 46 into G;

(b) a mutation of the amino acid residue K on position 77 into E;

(c) a mutation of the amino acid residue K on position 80 into E;

(d) a mutation of the amino acid residue E on position 92 into D;

(e) a mutation of the amino acid residue N on position 175 into P;

(f) a mutation of the amino acid residue G on position 184 into N;

(g) a mutation of the amino acid residue V on position 185 into N;

(h) a mutation of the amino acid residue K on position 201 into Q;

(i) a mutation of the amino acid residue K on position 209 into Q;

(j) a mutation of the amino acid residue K on position 421 into N;

(k) a mutation of the amino acid residue N on position 426 into S;

(l) a mutation of the amino acid residue K on position 465 into E or Q;

(m) a mutation of the amino acid residue D on position 486 into N;

(n) a mutation of the amino acid residue E on position 487 into Q, N or I; and

(o) a mutation of the amino acid residue K on position 508 into E.

7. The pre-fusion RSV F mutant polypeptide according to claim 1 , wherein the mutant polypeptide comprises at least two mutations.

8. The pre-fusion RSV F mutant polypeptide of claim 1 , wherein the heterologous trimerization domain comprises SEQ ID NO:3.

9. The pre-fusion RSV F mutant polypeptide according to claim 8 , wherein the trimerization domain is linked to amino acid residue 495 of the RSV F protein.

10. The pre-fusion RSV F mutant polypeptide of claim 1 , wherein the heterologous trimerization domain comprises SEQ ID NO:4.

11. The pre-fusion RSV F mutant polypeptide according to claim 10 , wherein the trimerization domain is linked to amino acid residue 513 of the RSV F protein.

12. The pre-fusion RSV F mutant polypeptide of claim 1 , wherein the linker between the F1 and the F2 domain comprises 5 amino acid residues.

13. The pre-fusion RSV F mutant polypeptide of claim 12 , wherein the linker comprises SEQ ID NO:5.

14. The pre-fusion RSV F mutant polypeptide of claim 1 , wherein the F1 domain and/or the F2 domain are from an RSV A strain.

15. The pre-fusion RSV F mutant polypeptide of claim 1 , wherein the F1 domain and/or the F2 domain are from an RSV B strain.

16. The pre-fusion RSV F mutant polypeptide of claim 1 , wherein the mutant polypeptide comprises a peptide selected from the group consisting of SEQ ID NO: 21-SEQ ID NO: 52 and SEQ ID NOs:71-89.

17. The pre-fusion RSV F mutant polypeptide of claim 1 , wherein the mutant polypeptide does not comprise a HIS-Tag.

18. A nucleic acid molecule encoding the pre-fusion RSV F mutant polypeptide of claim 1 .

19. The nucleic acid molecule of claim 18 , wherein the nucleic acid molecule is codon-optimized for expression in mammalian cells.

20. A vector comprising the nucleic acid molecule of claim 18 .

21. A composition comprising:

the pre-fusion RSV F mutant polypeptide of claim 1 , and a pharmaceutically acceptable carrier or excipient.

22. A method of inducing an immune response against RSV F protein in a subject, the method comprising:

administering to the subject the pre-fusion RSV F mutant polypeptide of claim 1 in an amount to induce an immune response against RSV F protein in the subject.

23. A vaccine comprising:

the pre-fusion RSV F mutant polypeptide of claim 1 .

24. A method of prophylaxing and/or treating RSV infection in a subject, the method comprising:

administering to the subject the pre-fusion RSV F mutant polypeptide of claim 1 , to prophylax against and/or treat the subject for RSV infection.

25. A vector comprising the nucleic acid molecule of claim 19 .

26. The pre-fusion RSV F mutant polypeptide according to claim 1 , comprising the mutation of the amino acid residue N/T at position 67 into I and the mutation of the amino acid residue S at position 215 into P.

27. The pre-fusion RSV F mutant polypeptide according to claim 26 , further comprising a mutation of the amino acid residue K at position 66 into E, a mutation of the amino acid residue I at position 76 into V, and a mutation of the amino acid residue D at position 486 into N.

28. A nucleic acid molecule encoding the pre-fusion RSV F mutant polypeptide of claim 26 .

29. A nucleic acid molecule encoding the pre-fusion RSV F mutant polypeptide of claim 27 .

30. A vector comprising the nucleic acid molecule of claim 28 .

31. A vector comprising the nucleic acid molecule of claim 29 .

32. A vaccine comprising the pre-fusion RSV F mutant polypeptide of claim 27 and/or a vector comprising a nucleic acid molecule encoding the same.

33. A method of prophylaxing and/or treating RSV infection in a subject, the method comprising:

administering to the subject the pre-fusion RSV F mutant polypeptide of claim 27 and/or a vector comprising a nucleic acid molecule encoding the same, to prophylax against and/or treat the subject for RSV infection.

34. The pre-fusion RSV F mutant polypeptide according to claim 26 , further comprising a mutation of the amino acid residue S at position 46 into G, a mutation of the amino acid residue K at position 66 into E, and a mutation of the amino acid residue I at position 76 into V.

35. A nucleic acid molecule encoding the pre-fusion RSV F mutant polypeptide of claim 34 .

36. A vector comprising the nucleic acid molecule of claim 35 .

37. A vaccine comprising the pre-fusion RSV F mutant polypeptide of claim 34 and/or a vector comprising a nucleic acid molecule encoding the same.

38. A method of prophylaxing and/or treating RSV infection in a subject, the method comprising:

administering to the subject the pre-fusion RSV F mutant polypeptide of claim 34 and/or a vector comprising a nucleic acid molecule encoding the same, to prophylax against and/or treat the subject for RSV infection.