Influenza hemagglutinin and neuraminidase variants

1. A 6:2 reassortant influenza A virus, wherein said virus comprises 6 internal genome segments from one or more donor viruses and 2 surface antigen genome segments, wherein the surface antigen genome segments encode an HA and a NA polypeptide, wherein the HA polypeptide comprises an amino acid sequence selected from SEQ ID NO: 89 and SEQ ID NO: 91.

2. The 6:2 reassortant influenza A virus of claim 1 , wherein said one or more donor viruses comprise one or more of the following phenotypes:

temperature-sensitive, cold-adapted, or attenuated.

3. The 6:2 reassortant influenza A virus of claim 1 , wherein said one or more donor viruses are selected from the group consisting of A/Ann Arbor/6/60 and A/Puerto Rico/8/34.

4. The 6:2 reassortant influenza A virus of claim 1 , wherein said reassortant influenza A virus is killed or inactivated.

5. The 6:2 reassortant influenza A virus of claim 1 , wherein said reassortant influenza A virus is a live attenuated reassortant influenza A virus.

6. An immunogenic vaccine composition comprising an immunologically effective amount of the reassortant influenza A virus of claim 1 , wherein the reassortant influenza A virus is split.

7. An immunogenic vaccine composition comprising an immunologically effective amount of the reassortant influenza A virus of claim 2 .

8. An immunogenic vaccine composition comprising an immunologically effective amount of the reassortant influenza A virus of claim 4 .

9. An immunogenic vaccine composition comprising an immunologically effective amount of the reassortant influenza A virus of claim 5 .

10. The immunogenic vaccine composition of claim 7 , wherein the reassortant influenza A virus is split.

11. A method for producing an influenza A virus in cell culture, the method comprising:

i) introducing into a population of host cells, which population of host cells is capable of supporting replication of influenza virus, a plurality of vectors comprising nucleotide sequences corresponding to:

(a) at least 6 internal genome segments of a first influenza strain; and, at least one genome segment encoding an HA surface antigen polypeptide wherein the surface antigen polypeptide comprises an amino acid sequence selected from SEQ ID NO: 89 and SEQ ID NO: 91; or

(b) at least 6 internal genome segments of a first influenza strain, which influenza strain comprises one or more phenotypic attributes selected from the group consisting of: attenuated, cold adapted and temperature sensitive; and, at least one genome segment encoding an HA surface antigen wherein the surface antigen polypeptide comprises an amino acid sequence selected from SEQ ID NO: 89 and SEQ ID NO: 91;

ii) culturing the population of host cells at a temperature less than or equal to 35° C.; and,

iii) recovering an influenza virus.

12. A method for stimulating the immune system of an individual to produce a protective immune response against influenza A virus, the method comprising administering to the individual an immunologically effective amount of the reassortant influenza A virus of claim 2 in a physiologically effective carrier.

13. A method for stimulating the immune system of an individual to produce a protective immune response against influenza A virus, the method comprising administering to the individual an immunologically effective amount of the reassortant influenza A virus of claim 4 in a physiologically effective carrier.

14. A method for stimulating the immune system of an individual to produce a protective immune response against influenza A virus, the method comprising administering to the individual an immunologically effective amount of the reassortant influenza A virus of claim 5 in a physiologically effective carrier.

15. A method of prophylactic or therapeutic treatment of an influenza A viral infection in a subject, the method comprising: administering to the subject, the reassortant influenza A virus of claim 2 in an amount effective to produce an immunogenic response against the influenza A viral infection.

16. A method of prophylactic or therapeutic treatment of an influenza A viral infection in a subject, the method comprising: administering to the subject, the reassortant influenza A virus of claim 4 in an amount effective to produce an immunogenic response against the influenza A viral infection.

17. A method of prophylactic or therapeutic treatment of an influenza A viral infection in a subject, the method comprising: administering to the subject, the reassortant influenza A virus of claim 5 in an amount effective to produce an immunogenic response against the influenza A viral infection.

18. The method of claim 15 , wherein the subject is a human.

19. The method of claim 16 , wherein the subject is a human.

20. The method of claim 17 , wherein the subject is a human.