Immunology (3)

• Humoral response


  1. B cells turn into plasma cells

  2. Plasma cells release antibodies
• When the antibody binds to the antigen


  • Crosslinking and phagocytosis is activated
  • Complements are activated
  • Toxins are neutralized
• C region in an antibody

  More constant sequence
• V region in an antibody


  Variable region and the antigen binding site
• Viruses


  Infectious agents which require a host or organism in order to replicate
• Viruses can infect a variety of living organisms
• Viral genome


  Contains one type of nucleotide - DNA or RNA
• Capsid


  Surrounds a viral nucleic acid
• Types of capsid


  • Naked
  • Enveloped
• Enveloped virus


  Surrounded by envelope of lipids and proteins
• Naked virus


  Capsid only, no envelope
• Capsid


  Protects the nucleic acid from the hosts acids and its protein digesting enzymes
• Icosahedral virus


  • 20 sided, 12 corners
  • Can be naked or enveloped
• Helical virus


  • Repeat units of a single polypeptide
  • Can be enveloped or naked
• Complex viruses


  More complicated structure than helical or icosahedral
• Viral genome classes


  • DNA virus classes 1, 2, 7
  • RNA virus classes 3 - 6
• RNA viruses show very rapid rates of mutation
• Mechanisms viruses use to evade detection


  • Changing their antigens so not they are recognized
  • Generalized immune suppression
• Viral replication cycle


  1. Attachment

  2. Penetration

  3. Uncoating

  4. Genome replication

  5. Assembly of virion

  6. Release
• Intrinsic resistance


  Some microbes may have some genetic material which prevents antibiotic action
• Acquired resistance


  Resistant strains of microbes emerge from previously sensitive bacterial population