Influenza virus vaccines and uses thereof

1. A polypeptide comprising:

(A) (a) (i) an influenza hemagglutinin HA1 domain that comprises an HA1 N-terminal stem segment, or a deleted form of said HA1 N-terminal stem segment, wherein up to 7, 6, 5, 4, 3, 2, or 1 amino acid residues are deleted, covalently linked to (ii) a linker of 1 to 50 heterologous residues that is in turn covalently linked to (iii) an HA1 C-terminal short stem segment, or a deleted form of said HA1 C-terminal short stem segment, wherein up to 7, 6, 5, 4, 3, 2, or 1 amino acid residues are deleted;

said HA1 domain being in tertiary association with

(b) an influenza hemagglutinin HA2 domain, wherein the amino acid sequence of the HA2 domain is at least 70%, 75%, 80%, 85%, 90%, 95%, 96% or 98% identical to the amino acid sequence of an HA2 from an H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15 or H16 influenza A,

wherein the HA1 N-terminal stem segment consists of amino acid residues HA1 N-term through A p of the HA1 domain, wherein HA1 N-term is the N-terminal amino acid of a mature HA0 protein lacking a signal peptide, and wherein A p is Cys that corresponds to amino acid position 52 of an HA1 domain using H3 numbering; and

wherein the HA1 C-terminal short stem segment consists of amino acid residues B q through HA1 C-term of an HA1 domain, wherein B q is Cys that corresponds to amino acid position 305 of an HA1 domain using H3 numbering, and wherein HA1 C-term is the C-terminal amino acid of the HA1 domain; or

(B) (a) (i) an influenza hemagglutinin HA1 domain that comprises a deleted form of an HA1 N-terminal stem segment, wherein up to 7, 6, 5, 4, 3, 2, or 1 amino acid residues are deleted, covalently linked to (ii) a linker of 1 to 50 heterologous residues that is in turn covalently linked to (iii) a sequence having at least 70%, 75%, 80%, 85%, 90%, 95%, 96% or 98% amino acid sequence identity to an HA1 C-terminal short stem segment from an H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15 or H16 influenza A;

said HA1 domain being in tertiary association with

(b) an influenza hemagglutinin HA2 domain, wherein the amino acid sequence of the HA2 domain is at least 70%, 75%, 80%, 85%, 90%, 95%, 96% or 98% identical to the amino acid sequence of an HA2 from an H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15 or H16 influenza A,

wherein the HA1 N-terminal stem segment consists of amino acid residues HA1 N-term through A p of the HA1 domain, wherein HA1 N-term is the N-terminal amino acid of a mature HA0 protein lacking a signal peptide, and wherein A p is Cys that corresponds to amino acid position 52 of an HA1 domain using H3 numbering; and

wherein the HA1 C-terminal short stem segment consists of amino acid residues B q through HA1 C-term of an HA1 domain, wherein B q is Cys that corresponds to amino acid position 305 of an HA1 domain using H3 numbering, and wherein HA1 C-term is the C-terminal amino acid of the HA1 domain.

2. The polypeptide of claim 1 , which is soluble.

3. The polypeptide of claim 1 , wherein the HA1 C-terminal short stem segment is covalently linked to the HA2 domain.

4. The polypeptide of claim 1 , wherein the polypeptide selectively binds neutralizing antiserum capable of binding an influenza hemagglutinin.

5. The polypeptide of claim 1 , wherein:

(a) said linker is of 1 to 40, 1 to 30 residues, 1 to 20 residues, 1 to 10 residues, 1 to 5 residues, 1 to 4 residues, 1 to 3 residues, 1 to 2 residues or 1 residue; or

(b) said linker is selected from the group consisting of GG, PG, GGG, GGGG (SEQ ID NO:560), GGGGG (SEQ ID NO 561), ITPNGSIPNDKPFQNVNKITYGA (SEQ ID NO:165), and NAS.

6. The polypeptide of claim 1 , wherein:

(a) the HA1 N-terminal stem segment comprises the amino acid sequence A17-A18-(Xaa) n -A 38 (SEQ ID NO:146), wherein

A 17 is Y or H;

A 18 is H, L, or Q;

(Xaa) n represents a sequence of 18-20 amino acid residues; and

A 38 is H, S, Q, T or N;

(b) the HA2 domain comprises the amino acid sequence A 18 -A 19 -A 20 -A 21 (SEQ ID NO:148), wherein

A 18 is V or I;

A 19 is D, N or A;

A 20 is G, and

A 21 is W;

(c) the HA2 domain comprises the amino acid sequence A 38 -A 39 -A 40 -A 41 -A 42 -A 43 -A 44 -A 45 -A 46 -A 47 -A 48 -A 49 -A 50 -A 51 -A 52 -A 53 -A 54 -A 55 -A 56 (SEQ ID NO:149),

wherein

A 38 is K, Q, R, L or Y;

A 39 is any amino acid residue;

A 40 is any amino acid residue;

A 41 is T;

A 42 is Q;

A 43 is any amino acid residue;

A 44 is A;

A 45 is I;

A 46 is D;

A 47 is any amino acid residue;

A 48 is I, V or M;

A 49 is T, Q or N;

A 50 is any amino acid residue;

A 51 is K;

A 52 is V or L;

A 53 is N;

A 54 is any amino acid residue;

A 55 is V, I or L; and

A 56 is V or I.

7. A nucleic acid encoding the polypeptide of claim 1 .

8. An isolated host cell expressing the nucleic acid of claim 7 .

9. A virus comprising a genome engineered to express the nucleic acid of claim 7 .

10. A virus comprising the polypeptide of claim 1 .

11. The virus of claim 9 , wherein the virus is:

a Newcastle disease virus (NDV), a vaccinia virus, an adenovirus, an adeno-associated virus (AAV), or a retrovirus;

(ii) influenza A virus or influenza B virus; or

(iii) inactivated or split.

12. The virus of claim 10 , wherein the virus is:

(i) a Newcastle disease virus (NDV), a vaccinia virus, an adenovirus, an adeno-associated virus (AAV), or a retrovirus;

(ii) influenza A virus or influenza B virus; or

(iii) inactivated or split.

13. A viral-like particle comprising the polypeptide of claim 1 .

14. An immunogenic composition comprising the polypeptide of claim 1 .

15. An immunogenic composition comprising the virus of claim 9 .

16. An immunogenic composition comprising the virus of claim 10 .

17. An immunogenic composition comprising the viral-like particle of claim 13 .

18. A method for immunizing a subject against influenza virus or preventing an influenza virus disease in a subject, comprising administering to the subject the immunogenic composition of claim 14 .

19. A method for immunizing a subject against influenza virus or preventing an influenza virus disease in a subject, comprising administering to the subject the immunogenic composition of claim 15 .

20. A method for immunizing a subject against influenza virus or preventing an influenza virus disease in a subject, comprising administering to the subject the immunogenic composition of claim 16 .

21. A method for immunizing a subject against influenza virus or preventing an influenza virus disease in a subject, comprising administering to the subject the immunogenic composition of claim 17 .

22. A method for treating an influenza virus infection or influenza virus disease in a subject, comprising administering to the subject the immunogenic composition of claim 14 .

23. A method for treating an influenza virus infection or influenza virus disease in a subject, comprising administering to the subject the immunogenic composition of claim 15 .

24. A method for treating an influenza virus infection or influenza virus disease in a subject, comprising administering to the subject the immunogenic composition of claim 16 .

25. A method for treating an influenza virus infection or influenza virus disease in a subject, comprising administering to the subject the immunogenic composition of claim 17 .

26. The method of claim 18 , wherein the subject is a human.

27. The method of claim 22 , wherein the subject is a human.