title: Identification and characterisation of a novel anti-viral peptide against avian influenza virus H9N2.
abstract: BACKGROUND
  Avian influenza viruses (AIV) cause high morbidity and mortality among the poultry worldwide. Their highly mutative nature often results in the emergence of drug resistant strains, which have the potential of causing a pandemic. The virus has two immunologically important glycoproteins, hemagglutinin (HA), neuraminidase (NA), and one ion channel protein M2 which are the most important targets for drug discovery, on its surface. In order to identify a peptide-based virus inhibitor against any of these surface proteins, a disulfide constrained heptapeptide phage display library was biopanned against purified AIV sub-type H9N2 virus particles.
  
  
  RESULTS
  After four rounds of panning, four different fusion phages were identified. Among the four, the phage displaying the peptide NDFRSKT possessed good anti-viral properties in vitro and in ovo. Further, this peptide inhibited the hemagglutination activity of the viruses but showed very little and no effect on neuraminidase and hemolytic activities respectively. The phage-antibody competition assay proved that the peptide competed with anti-influenza H9N2 antibodies for the binding sites. Based on yeast two-hybrid assay, we observed that the peptide inhibited the viral replication by interacting with the HA protein and this observation was further confirmed by co-immunoprecipitation.
  
  
  CONCLUSIONS
  Our findings show that we have successfully identified a novel antiviral peptide against avian influenza virus H9N2 which act by binding with the hemagglutination protein of the virus. The broad spectrum activity of the peptide molecule against various subtypes of the avian and human influenza viruses and its comparative efficiency against currently available anti-influenza drugs are yet to be explored.
authors.affiliation: Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, UPM Serdang, Selangor, 43400, Malaysia. mmdrajik@gmail.com
authors.forename: Mohamed
authors.initials: M
authors.lastname: Rajik
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Jahanshiri
authors.forename: Abdul Rahman
authors.initials: AR
authors.lastname: Omar
authors.forename: Aini
authors.initials: A
authors.lastname: Ideris
authors.forename: Sharifah Syed
authors.initials: SS
authors.lastname: Hassan
authors.forename: Khatijah
authors.initials: K
authors.lastname: Yusoff
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D006389:Hemagglutinins, Viral / Q000378:metabolism*; D053127:Influenza A Virus, H9N2 Subtype / Q000187:drug effects*; D019151:Peptide Library; D010455:Peptides / Q000494:pharmacology*; D011485:Protein Binding; D020798:Two-Hybrid System Techniques
chemical_list: D000998:Antiviral Agents; D006389:Hemagglutinins, Viral; D019151:Peptide Library; D010455:Peptides; C458881:hemagglutinin fusogenic peptide, influenza virus