Interferon-induced Transmembrane Protein 3 Prevents Acute Influenza Pathogenesis in Mice

Objective Interferon-induced transmembrane protein 3(IFITM3)is an important member of the IFITM family.However,the molecular mechanisms underlying its antiviral action have not been completely elucidated.Recent studies on IFITM3,particularly those focused on innate antiviral defense mechanisms,have shown that IFITM3 affects the body’s adaptive immune response.The aim of this study was to determine the contribution of IFITM3 proteins to immune control of influenza infection in vivo.Methods We performed proteomics,flow cytometry,and immunohistochemistry analysis and used bioinformatics tools to systematically compare and analyze the differences in natural killer(NK)cell numbers,their activation,and their immune function in the lungs of Ifitm3-/-and wild-type mice.Results Ifitm3-/-mice developed more severe inflammation and apoptotic responses compared to wild-type mice.Moreover,the NK cell activation was higher in the lungs of Ifitm3-/-mice during acute influenza infection.Conclusions Based on our results,we speculate that the NK cells are more readily activated in the absence of IFITM3,increasing mortality in Ifitm3-/-mice.

A Novel Reassortant H2N3 Influenza Virus Isolated from China

Objective To analyze the genetic composition of a novel H2N3 virus isolate identified from a duck cage swab in a live poultry market （LPM） in 2009 in Guangdong province of China. Methods PCR-positive specimens were inoculated into embryonated chicken eggs and subtyped by conventional RT-PCR. All segments of the virus A/environment/Guangdong/2/2009 were sequenced, and phylogenetic trees were constructed and analyzed. Results The genes of this virus belong to Eurasian-lineage avian viruses. The virus is a reassortant with the HA gene from an H2N2 virus and the NA gene from an H5N3 virus. The PB1, PB2, and NP genes were from an H4N6 virus, the PA was from an H3N8 virus, the M gene was from an H1N3 virus, and the NS gene was from an H10N6 virus. Conclusion market. Its A novel avian-origin reassortant H2N3 influenza virus was detected in a live poultry potential impacts and evolution should be closely monitored.

A Novel Reassortant H3N8 Influenza Virus Isolated from Drinking Water for Duck in a Domestic Duck Farm in Poyang Lake Area

Objective To conduct a full genome sequence analysis for genetic characterization of an H3N8 influenza virus isolated from drinking water of a domestic duck farm in Poyang Lake area in 2011. Methods The virus was cultivated by specific pathogen free （SPF） chicken embryo eggs and was subtyped into hemagglutinin （HA） and neuraminidase （NA） by real-time PCR method. Eight gene segments were sequenced and phylogenetic analysis was conducted. Results The NA gene of this virus belongs to North American lineage; other seven genes belong to Eurasian lineage. Compared with the viruses containing NA gene, the PB2 and PB2 gene came from different clades. And this indicates that the virus was a novel reassortant genotype. The HA receptor binding preference was avian-like and the cleavage site sequence showed a low pathogenic feature. There was no drug resistance mutation of M2 protein. The mutations of Asn30Asp, and Thr225Ala of the M1 protein implied the potential of pathogenicity increase in mice. Conclusion The finding of novel genotype of H3N8 virus in drinking water in this duck farm near Poyang Lake highlighted the importance of strengthening the surveillance of avian influenza in this region, which could contribute to pinpointing the influenza ecological relations among avian, swine, and human.

H5N1 Avian Influenza Pre-pandemic Vaccine Strains in China

Objective To prepare the 4 candidate vaccine strains of H5N1 avian influenza virus isolated in China Methods Recombinant viruses were rescued using reverse genetics. Neuraminidase （NA） and hemagglutinin （HA） segments of the A/Xinjiang/1/2006, A/Guangxi/1/2009, A/Hubei/1/2010, and A/Guangdong/1/2011 viruses were amplified by RT-PCR. Multibasic amino acid cleavage site of HA was removed and ligated into the pCIpoll vector for virus rescue. The recombinant viruses were evaluated by trypsin dependent assays. Their embnjonate survival and antigenicity were compared with those of the respective wild-type viruses. Results The 4 recombinant viruses showed similar antigenicity compared with wild-type viruses, chicken embryo survival and trypsin-dependent characteristics. Conclusion The 4 recombinant viruses rescued using reverse genetics meet the criteria for classification of low pathogenic avian influenza strains, thus supporting the use of them for the development of seeds and production of pre-pandemic vaccines.