Influenza virus recombinant proteins

1. A recombinant vector comprising a polynucleotide encoding an influenza polypeptide comprising:

a. at least a portion of an influenza Hemagglutinin-1 (HA-1) domain; and

b. lacking:

a Hemagglutinin-2 (HA-2) domain; or

both a Hemagglutinin-2 (HA-2) domain and a Hemagglutinin transmembrane domain;

wherein the portion consists of (i) an influenza amino acid sequence at least 80% identical to an amino acid sequence corresponding to positions 1-259 of SEQ ID NO: 1, 2, 3, 4, 5, 6 or 7, or (ii) an influenza amino acid sequence at least 90% identical to an amino acid sequence corresponding to positions 1-320 of SEQ ID NO: 1, 2, 3, 4, 5 or 6, and wherein the influenza amino acid sequence comprises the amino acids isoleucine (I) or leucine (L) at the amino acid corresponding to position 3, the amino acid cysteine (C) at the amino acid corresponding to position 4, the amino acids I, L or valine (V) at the amino acid corresponding to position 5, and the amino acid glycine (G) at the amino acid corresponding to position 6 of SEQ ID NO: 2,

wherein administration of oligomers of the polypeptide to an animal generates neutralizing antibodies against an influenza virus.

2. A host cell comprising the recombinant vector of claim 1 .

3. The recombinant vector of claim 1 , wherein the polypeptide binds to conformation sensitive influenza neutralizing antibodies.

4. The recombinant vector of claim 1 , wherein the portion consists of an influenza amino acid sequence at least 90% identical to positions 1-259 of SEQ ID NOS: 1, 2, 3, 4, 5, 6, or 7.

5. The recombinant vector of claim 1 , wherein the portion consists of positions 1-259 of SEQ ID NOS: 1, 2, 3, 4, 5, 6 or 7.

6. The recombinant vector of claim 1 , wherein the portion consists of an influenza amino acid sequence at least 95% identical to positions 1-320 of SEQ ID NO: 1, 2, 3, 4, 5 or 6.

7. The recombinant vector of claim 1 , wherein the portion consists of positions 1-320 of SEQ ID NO: 1, 2, 3, 4, 5 or 6.