Influenza C virus is an important respiratory pathogen not only infecting people, but also pigs, dogs, and other animals. Polymerase is central to the replication of influenza C virus and is an important target for studying the mechanism of viral replication. However, there is no commercial monoclonal antibody (MAb) targeting influenza C virus polymerase, which hampers the development of relevant research to some extent. In order to prepare MAb targeting the polymerase basic protein 2 (PB2) of influenza C virus, influenza C virus RNA-dependent RNA polymerase (RdRp, consists of PB1, PB2 and P3) was co-immunoprecipitated with Flag-tagged human acidic nuclear phosphoprotein 32A (huANP32A-Flag) from 293T cells based on the interaction between huANP32A and influenza virus RdRp. The purified RdRp was used as antigen to immunize BALB/c mice. Six positive hybridoma cell lines (7B11-5, 8A4-5, 13D9-6, 8D4-1, 8D4-3, 9F9-4) that stably secrete and recognize PB2 MAb were screened by indirect ELISA and Western blotting. The subtypes of MAb 7B11-5, 8A4-5, 8D4-1 and 8D4-3 antibody were identified as IgG1, the subtypes of MAb 13D9-6 and 9F9-4 were IgG2a and IgG3, respectively. All the light chains of the MAbs were κ chain. A hybridoma cell line 8D4-1 with high titer was further selected to prepare ascites. The titer of mouse ascites antibody was determined to be 1:64 000. Western blotting results showed that the MAb 8D4-1 had a specific immune response with ICV PB2; laser confocal assay showed that the prepared MAb 8D4-1 accurately detected the subcellular localization of PB2 subunits. Moreover, ICV RdRp was highly enriched by ANP32A. The high specific of the prepared PB2 MAb 8D4-1 may facilitate the polymerase detection, structural analysis and mechanism study of influenza C virus.
Animals ; Antibodies, Monoclonal/metabolism* ; Ascites ; Humans ; Influenzavirus C/metabolism* ; Mice ; Nuclear Proteins/metabolism* ; RNA-Binding Proteins ; RNA-Dependent RNA Polymerase/genetics* ; Viral Proteins/metabolism* ; Virus Replication

Influenza C virus, a member of the Orthomyxoviridae family, causes flu-like disease but typically only with mild symptoms. Humans are the main reservoir of the virus, but it also infects pigs and dogs. Very recently, influenza C-like viruses were isolated from pigs and cattle that differ from classical influenza C virus and might constitute a new influenza virus genus. Influenza C virus is unique since it contains only one spike protein, the hemagglutinin-esterase-fusion glycoprotein HEF that possesses receptor binding, receptor destroying and membrane fusion activities, thus combining the functions of Hemagglutinin (HA) and Neuraminidase (NA) of influenza A and B viruses. Here we briefly review the epidemiology and pathology of the virus and the morphology of virus particles and their genome. The main focus is on the structure of the HEF protein as well as on its co- and post-translational modification, such as N-glycosylation, disulfide bond formation, S-acylation and proteolytic cleavage into HEF1 and HEF2 subunits. Finally, we describe the functions of HEF: receptor binding, esterase activity and membrane fusion.
Animals ; Cattle ; Dogs ; Hemagglutinins, Viral ; chemistry ; metabolism ; Influenzavirus C ; physiology ; Orthomyxoviridae Infections ; metabolism ; virology ; Protein Conformation ; Protein Folding ; Protein Processing, Post-Translational ; Viral Fusion Proteins ; chemistry ; metabolism

INTRODUCTIONSince the emergence of the pandemic influenza A/H1N1/2009 virus in April 2009, diagnostic testing in many countries has revealed the rapid displacement and then replacement of circulating seasonal influenza viruses by this novel virus.

MATERIALS AND METHODSIn-house seasonal and pandemic influenza-specific polymerase chain reaction assays were introduced and/or developed at the Molecular Diagnosis Centre (MDC) at the National University Hospital (NUH), Singapore. These assays have been used to test all samples received from in-patients, out-patients, staff and visitors for suspected pandemic influenza A/H1N1/2009 infection.

RESULTSPrior to the arrival of the pandemic A/H1N1/2009 virus in Singapore at the end of May 2009, seasonal influenza A/H3N2 predominated in this population, with very little seasonal influenza A/H1N1 and B viruses detected. Within about 1 month of its arrival in Singapore (mainly during June to July 2009), this pandemic virus rapidly displaced seasonal influenza A/H3N2 to become the predominant strain in the Singaporean population served by MDC/NUH.

CONCLUSIONSRealtime molecular techniques have allowed the prompt detection of different influenza subtypes during this current pandemic, which has revealed the displacement/replacement of previously circulating seasonal subtypes with A/H1N1/2009. Although some of this may be explained by immunological cross-reactivity between influenza subtypes, more studies are required.

Communicable Diseases, Emerging ; Cross Reactions ; Disease Outbreaks ; Humans ; Influenza A Virus, H1N1 Subtype ; isolation & purification ; Influenza B virus ; isolation & purification ; Influenza, Human ; classification ; diagnosis ; epidemiology ; Influenzavirus C ; isolation & purification ; Molecular Diagnostic Techniques ; Polymerase Chain Reaction ; Singapore ; epidemiology

OBJECTIVETo observe the influence of the 4 parts of forming of Yiqi Qingwen Jidu Heji(YQQWJDHJ) to lung inflammatory cytokines of the model rats infected with influenza virus dynamically, and to discuss the mechanism of 4 parts of forming to anti-influenza immune injury and restoration.

METHODAt the different stages of infection with the model rats infected by FM1 influenza, expression in lung of TNF-alpha, IL-6, IL-1, IL-10 and IFN-gamma was detected after the intervention of 4 parts of forming using ELISA method.

RESULTThe expression of TNF-alpha, IL-6, IL-1 and IFN-gamma of model rats infected by FM1 were higher than the control group, the expression of IL-10 did not change. The expression of TNF-alpha was significantly reduced in 3 to 5 days after infection. By the method of relieving superficies with acrid-cold, clearing away heat and poison and replenishing Qi, the lung expression of IFN-gamma was significantly increased in the stage after infection. The method of relieving superficies with acrid-warm significantly reduced lung expression of IL-6 after infection in 1 to 3 days and on the 7th day, decreased the expression of IL-1 in 3 to 7 days, increased IFN-gamma expression on the 3rd day and the 7th day, and significantly increased the expression of IL-10 on the 1st day and in 5 to 7 days. The method of relieving superficies with acrid-cold reduced the expresssion of IL-6 after infection, and significantly increased the expression of IL-10. It could increase the expression of IL-1 after infection on the 3rd day, but reduced IL-1 expression after infection 7 days. The method of clearing away heat and poison reduced lung IL- 6 expression after infection in 3 to 7 days significantly, decreased the expression of IL-1 in 5 to 7 days, also increased the lung expression of IL-10 in 1 to 5 days significantly. The method of replenishing Qi significantly reduced the expression of IL-6 after infection on the 1st day and in 5 to 7 days, decreased the expression of IL-1 in 3 to 7 days, also significantly increased the lung IL-10 on the 5th day after infection.

CONCLUSIONThe method of clearing away heat and poison and replenishing Qi could be against the lung immune inflammatory damage and repair damage. The method of relieving superficies with acrid-warm demonstrated some immunity against lung injury on the 3rd day after infection and the method of relieving superficies with acrid-cold demonstrated some immunity against lung injury on the 5th days after infection.

Animals ; Chemistry, Pharmaceutical ; methods ; Cytokines ; immunology ; Disease Models, Animal ; Drugs, Chinese Herbal ; administration & dosage ; chemistry ; Humans ; Influenza, Human ; drug therapy ; immunology ; virology ; Influenzavirus A ; immunology ; physiology ; Lung ; drug effects ; immunology ; Male ; Mice ; Mice, Inbred BALB C ; Random Allocation ; Treatment Outcome

OBJECTIVETo construct a replication-defective recombinant adenovirus expressing the fusion gene of neuraminidase (NA) gene in influenza virus A/FM/1/47 and C3d and to evaluate the induced immune efficacy.

METHODSNA-C3d was cloned into shutter vector pAdTrack-CMV, which was cotransformated with adenovirus DNA into E. coli BJ5183. The recombinant adenovirus genomic DNA was generated through homological recombination. The recombinant adenovirus was produced by transfecting 293 cell line with the genomic DNA and the induced immune efficacy in mice were analyzed.

RESULTSThe integration of NA-C3d in the adenovirus genomic DNA and its expression were confirmed by PCR and Western-Blot assays respectively. After intranasal immunization, the serum IgG was induced at a titer of 1: 1000 and 1:100 000 in BALB/c mice at primary and secondary immunization respectively. The vaccinated mice were completely survived when challenged with wide influenza virus.

CONCLUSIONrecombinant adenovirus expressing NA-C3d was successfully constructed and it could induce desired immune efficacy.

Adenoviridae ; genetics ; metabolism ; physiology ; Animals ; Cloning, Molecular ; Complement C3d ; biosynthesis ; genetics ; Genetic Vectors ; genetics ; Immunoglobulin G ; immunology ; Influenzavirus A ; enzymology ; genetics ; Mice ; Mice, Inbred BALB C ; Neuraminidase ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Transfection ; methods ; Virus Replication