Influenza hemagglutinin and neuraminidase variants

A method for producing reassortant influenza viruses in cell culture, the method comprising:

• i) introducing a plurality of vectors comprising polynucleotides corresponding to an influenza virus genome into a population of host cells capable of supporting replication of influenza virus, which plurality of vectors comprises polynucleotides corresponding to at least 6 internal genome segments of a first influenza strain, and at least one genome segment of a second influenza strain, wherein the at least one genome segment of the second influenza strain comprises a nucleotide sequence encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:18;
• ii) culturing the population of host cells;
• and
• iii) recovering a plurality of reassortant influenza viruses comprising a polypeptide comprising the amino acid sequence of SEQ ID NO:18.

A method of prophylactic or therapeutic treatment of an influenza viral infection in a subject, the method comprising:

• administering to the subject, a reassortant influenza virus comprising:
• a) a polynucleotide comprising a nucleotide sequence of SEQ ID NO:17;
• or
• b) a polynucleotide sequence encoding a polypeptide comprising an amino acid sequence of SEQ ID NO:18;
• in an amount effective to produce an immunogenic response against the influenza viral infection.