objective: survey of molecular characterization of nucleoprotein gene of h9n2 avian influenza viruses and determination of the genetic relationship of iranian h9n2 viruses and other asian viruses. materials and methods: the nucleoprotein (np) genes from 4 isolates of h9n2 viruses isolated from commercial chickens in iran during 2008-2009 were amplified by rt-pcr method and sequenced. nucleotid...

Influenza nucleoprotein (NP) is a major component of the ribonucleoprotein (vRNP) in influenza virus, which functions for the transcription and replication of viral genome. Compared to the nucleoprotein of influenza A (ANP), the N-terminal region of influenza B nucleoprotein (BNP) is much extended. By virus reconstitution, we found that the first 38 residues are essential for viral growth. We f...

Influenza viruses are among the most common pathogens that threaten the health of humans and animals worldwide. Various anti-viral therapeutic agents are currently used for treatment and prophylaxis of influenza virus, but the targets of these drugs are easily mutated and result in resistance. Therefore, medications that have broad spectrum coverage are urgently needed to combat with the diseas...

Influenza virus poses a difficult challenge for protective immunity. This virus is adept at altering its surface proteins, the proteins that are the targets of neutralizing antibody. Consequently, each year a new vaccine must be developed to combat the current recirculating strains. A universal influenza vaccine that primes specific memory cells that recognise conserved parts of the virus could...

objective: the use of bacterial plasmids carrying specific genes of pathogens as genetic vaccines is a relatively new technique for induction of cellular immune responses against microbial pathogens. mechanisms of production of specific immune responses against these vaccines are not still completely understood. therefore, it is necessary to examine various routes of inoculation to find the bes...

Viruses can exploit a variety of strategies to evade immune surveillance by cytotoxic T lymphocytes (CTL), including the acquisition of mutations in or adjacent to CTL epitopes. Recently, an amino acid substitution (R384G) in an HLA-B*2705-restricted CTL epitope in the influenza A virus nucleoprotein (nucleoprotein containing residues 383 to 391 [NP(383-391)]; SRYWAIRTR, where R is the residue ...

Here, we describe a new HLA-B*3501-restricted cytotoxic T lymphocyte (CTL) epitope in the influenza A virus (H3N2) nucleoprotein, which was found to exhibit a high degree of variation at nonanchor residues. The influenza virus variants emerged in chronological order, and CTLs directed against old variants failed to recognize more recent strains of influenza A virus, indicating an escape from CT...

Local administration of nucleoprotein purified from X31 (H3N2) influenza A virus primed for A virus cross-reactive cytotoxic T cells and resulted in substantial protection (75%) of mice from a lethal challenge with the heterologous mouse-adapted A/PR/8/34 (H1N1) virus. By following the course of a lethal virus challenge we found that nucleoprotein priming did not prevent virus infection but rat...

Human influenza A virus-specific, cytotoxic T cells have been shown previously to recognize the virus nucleoprotein on infected cells. CTL preparations from four HLA B37-positive donors were shown to recognize a synthetic peptide that corresponded to amino acids 335-349 of the nucleoprotein sequence. Influenza-specific CTL from 10 donors of other HLA types failed to recognize this epitope. CD8+...

Alpaca-derived single-domain antibody fragments (VHHs) that target the influenza A virus nucleoprotein (NP) can protect cells from infection when expressed in the cytosol. We found that one such VHH, αNP-VHH1, exhibits antiviral activity similar to that of Mx proteins by blocking nuclear import of incoming viral ribonucleoproteins (vRNPs) and viral transcription and replication in the nucleus. ...