Virus

    Cards (86)

    • What are three modes of viral infection mentioned?
      Across mucosa, broken skin, bites
    • What does a virus use to replicate?
      Cell machinery
    • What process leads to numerous mutations in new virions?
      Replication
    • How do viruses infect target cells?
      Binding to specific cell-surface receptors
    • Which areas does the Influenza virus infect?
      Upper respiratory tract
    • What was the death toll of the influenza pandemic in 1918-1919?
      20-50 M people
    • What type of virus is influenza?
      Enveloped RNA virus
    • How many single-strand RNAs (ssRNA) does the influenza virus have?
      8
    • How many proteins do the 8 single-strand RNAs (ssRNA) of the influenza virus produce?
      10
    • What molecule does Hemagglutinin (HA) bind to?
      Cell surface sialic acid (SA) groups
    • What is the role of Neuraminidase (NA)?
      Facilitate budding by cleaving N-acetylneuraminic acid
    • What is the main capsid protein of the influenza virus?
      M1
    • What is the function of the M2 protein in influenza?
      Ion channel important in unpacking
    • What are the three basic types of influenza viruses classified by?
      Nucleoprotein and matrix proteins
    • Which type of influenza is most common and causes major pandemics?
      Type A
    • Which influenza types infect humans and seals?
      Type B
    • Which influenza type causes mild illness?
      Type C
    • What causes the subtypes of type A influenza virus?
      Variations in HA and NA
    • How many different HA subtypes are there?
      13
    • How many different NA subtypes are there?
      9
    • What influenza strain is known as swine flu?
      H1N1
    • What influenza strain is known as bird flu?
      H5N1
    • What is the first immune response after breach of protective barriers?
      Natural IgM + complement
    • What kind of antibodies are present in the first infection?
      NO virus-specific antibodies
    • How does the humoral response neutralize/lyse a virus?
      Virus neutralisation / lysis
    • What is the function of natural IgM antibodies?
      Recognize markers on apoptotic cells
    • What do natural IgM antibodies enhance?
      Phagocytic clearance of dead cells
    • What do natural IgM antibodies recognize?
      A wide range of viral antigens
    • What is the role of Natural IgM antibodies?
      Protect against a variety of pathogens
    • What do initial immune responses limit?
      Initial viral dissemination
    • What type of cell causes cytotoxicity in initial immune responses?
      NK and Tc
    • What cells activate T cells?
      Antigen-presenting cells
    • What two interactions does the entry of a virus into a host cell depend on?
      Adhesion molecules and entry receptors
    • What two molecules are expressed by infected cells?
      Type I IFNs and IL-12
    • What is the effect of type I IFNs expression in infected cells?
      Inhibition of protein synthesis
    • What receptor do IFN-α and –β bind?
      IFN α/β receptor
    • What is the effect of IFN-α and –β binding to IFN α/β receptor?
      Increased expression of specific genes
    • What enzyme degrades viral RNA?
      RNAse L
    • What is stimulated by IFN types I + IL-12?
      NK cells
    • What is the result of NK cell stimulation?
      Apoptosis of infected cell