Novel influenza virus

Abstract

The present invention provides a novel influenza virus wherein both the NS and the PB1 gene segments are modified and wherein the PB1-F2 open reading frame is modified by introduction of at least one stop codon. Specifically, the influenza virus is lacking functional NS1 and PB1-F2 proteins. Additionally, a vaccine formulation comprising said modified influenza virus is provided and its use for prevention of influenza infection.

1 - 14 . (canceled) 
     
     
         15 . An influenza virus comprising:
 an NS1 gene, wherein the NS1 gene comprises an insertion, substitution or deletion of at least one nucleotide, and wherein the influenza virus has reduced replication activity, the replication rate of the influenza virus in interferon competent cells being at least less than 5% than that of the wild type influenza virus.   
     
     
         16 . The influenza virus of  claim 15 , wherein the virus is replication deficient. 
     
     
         17 . The influenza virus of  claim 15 , wherein the NS1 gene encodes a truncated NS1 protein. 
     
     
         18 . The influenza virus of  claim 15 , wherein the NS1 gene fails to encode a protein. 
     
     
         19 . The influenza virus of  claim 17 , wherein the truncated NS1 protein lacks a functional RNA binding domain. 
     
     
         20 . The influenza virus of  claim 17 , wherein the NS1 protein lacks amino acids 1 through 73, or a portion thereof. 
     
     
         21 . The influenza virus of  claim 17 , wherein the NS1 protein lacks an effector function. 
     
     
         22 . The influenza virus of  claim 17 , where at least one amino acid at any one of the positions 74 through 230 of the NS1 protein is modified. 
     
     
         23 . The influenza virus of  claim 22 , where at least one amino acid at any one of the positions 134 through 161 of the NS1 protein is modified. 
     
     
         24 . The influenza virus of  claim 15 , further comprising:
 a PB1-F2 open reading frame (ORF) comprising a modification, the modification comprising at least one stop codon.   
     
     
         25 . The influenza virus of  claim 24 , wherein the PB1-F2 ORF comprises a PB1 segment, wherein the PB1 segment is modified by introduction of multiple stop codons. 
     
     
         26 . The influenza virus of  claim 25 , wherein the PB1 segment of the PB1-F2 ORF is modified at any of nucleotide positions T120, T153, T222, T234, T255, T270 and G291 according to the numbering of SEQ ID NO: 1. 
     
     
         27 . The influenza virus of  claim 24 , wherein the modification of the PB1 segment of the PB1-F2 ORF results in a knock out of the PB1-F2 ORF. 
     
     
         28 . The influenza virus of  claim 24 , wherein the virus comprises the nucleotide sequence of SEQ ID NO: 2. 
     
     
         29 . The influenza virus of  claim 24 , wherein the PB1-F2 ORF expressing the PB1-F2 protein comprises the amino acid sequence of SEQ ID NO: 4. 
     
     
         30 . The influenza virus of  claim 24 , wherein the virus lacks functional NS1 and PB1-F2 proteins. 
     
     
         31 . An influenza vaccine, comprising:
 an influenza virus lacking a functional NS1 protein and a functional PB1-F2 protein, wherein the influenza vaccine is capable of generating high titers of virus-specific antibody, and a broad spectrum protection against influenza virus by significantly stimulating Th2 type immune response.   
     
     
         32 . The vaccine according to  claim 31 , further comprising:
 a pharmaceutically acceptable carrier.   
     
     
         33 . The vaccine according to  claim 31 , wherein the vaccine is formulated for intranasal delivery. 
     
     
         34 . A method of preventing disease caused by influenza virus infection of an individual comprising the step of:
 administering a vaccine to the individual, wherein the vaccine comprises the influenza virus of  claim 31 .   
     
     
         35 . The method of  claim 34 , wherein the vaccine is administered intranasally.