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Avian Influenza Virus

Avian Influenza Virus. MDG5101 Advanced Cell Biology Bioinformatics Group 6 Presentation Liu Ka Po, Gabriel  Jayapal Manikandan  Annette Shoba Vincent  Lee Guan Huei  Mok Wei Chuen. Avian Influenza Virus. To date: 186 confirmed human cases. 105 deaths.

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Avian Influenza Virus

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  1. Avian Influenza Virus MDG5101 Advanced Cell BiologyBioinformatics Group 6 Presentation Liu Ka Po, Gabriel  Jayapal Manikandan  Annette Shoba Vincent  Lee Guan Huei  Mok Wei Chuen

  2. Avian Influenza Virus To date: 186 confirmed human cases. 105 deaths.

  3. Mechanism of infection and replication For human influenza viruses, they bind to receptors that contain terminal 2-6-linked sialyl-galactosyl residues. PNAS 2004; 101:4620-4.

  4. Antigenic Shift Antigenic Drift Person infected with virus Develop Ab against the virus New viral strain appears Reinfection occurs • small changes in the virus that happen continually over time. • Antigenic drift produces new virus strains that may not be recognized by the body's immune system. • abrupt, major change in the influenza A viruses • resulting in new hemagglutinin and/or new hemagglutinin and neuraminidase proteins in influenza viruses that infect humans

  5. Avian Influenza Virus Data Search Avian influenza virus web sites can be searched via: Information can be obtained by the following data sources in the following relevant public domains. For examples: http://www.ncbi.nlm.nih.gov/genomes/FLU/FLU.html http://www.who.int/csr/disease/avian_influenza/en/ http://www.cdc.gov/flu/avian/

  6. Avian Influenza Virus Genome Search • Entrez Genome by NCBI

  7. Current Diagnostic Test • Rapid Antigen Detection • Near-patient tests for influenza • Immunofluorescence assay • Enzyme Immunoassay • Virus Culture • PCR and Real-time PCR • Recommended laboratory tests to identify avian influenza A virus in specimens from humans • WHO Geneva • June 2005

  8. RT-PCR Kit for New Mutant Detection • Primers built on conserved sequences • H5 (Yuen et al. 1998), N1 (Wright et al. 1995) conserved sequences (Genbank) • Multiple Sequence Alignment (ClustalW) • Bands detection (Addition/Deletion) • Expected bands vs. Unexpected bands • Unexpected bands could indicate possible new mutant variants • PCR-RFLP (Point Mutation) • Restriction enzymes digestion • Signatory fragments • Followed up by sequencing Yuen KY et al. (1998). Clinical features and rapid viral diagnosis of human disease associated with avian influenza A H5N1 virus. Lancet, 351:467–471. Wright KE et al. (1995). Typing and subtyping of influenza viruses in clinical samples by PCR. Journal of Clinical Microbiology, 33:1180–1184.

  9. Biological Database • Represent an extraordinarily diverse collection. • Future advances in biology depend critically on databases Definition:Large, organized body of persistent data, associated with computerized software designed to update, query, and retrieve components of the data. • Additional requirements must be met: • Easily accessible via WWW & • A method for extracting (answer a specific biological question) • SQL - access the data and structures within a relational database. • PHP - create dynamic Web pages that are generated from information accessed from a MySQL database.

  10. Protein Structure Analysis & Visualization

  11. Present Treatment Options • Neuraminidase Inhibitors: Tamiflu (oseltamivir) and Relenza (zanamivir) – 1st choice but resistant cases reported • Adamantanes: Amantadine and Rimantandine – not drug of choice due to high resistance rate

  12. New Drugs in Development – Potential Targets • Proteolytic activation of haemagglutinin, eg Camostat • Attachment of the virus to specific cell-surface receptors, eg sialic acid analogs • Endocytosis and fusion with the endosomal membrane, eg Anionic polymers • Uncoating of the nucleocapsid, eg Bafilomycin • Multiplication, i.e. synthesis of viral RNA and mRNA, eg Flutimide, siRNA

  13. Speed up drug development • Traditional vs Rational Drug Design • “Using structural information about drug targets or their natural ligands as a basis for the design of effective drugs.” • Achieve through proteomics, lipidomics, structural biology, bioinformatics • Computer programmes to search through databases • Avoid the expense of large-scale screening and save time • Zanamivir is the first successful case

  14. Vaccines Live attenuated vaccines: • Weak or weakened strains of virulent agent • Closely related species which provide cross-protection Inert vaccine: • Killed or inactivated • Recombinant • Fractionated

  15. Vaccine design KNOWLEDGE • Understanding our immune responses • Pathogen-host interface • Antigen processing and presentation • Immune memory TECHNOLOGY • Genome mining as a mean to identify target antigens • New protein expression systems • Rationally-designed adjuvants and vector systems TARGET DEVELOPMENT Fast mutation rates thus requires constant reformulation of the vaccine design

  16. Acknowledgements A/P Tan Tin Wee A/P Shoba Ranganathan

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