microbiology and immunology lecture 19

• Innate immunology


  Working within us all the time
• CGD

  Chronic granulomatous Disease
• Innate immunity


  • Simple recognition systems, has limited capacity, has no memory so a slow response to the disease when it comes again
• Adaptive immune system

  • More sophisticated recognition, highly specific and a good memory
• Physical and chemical barriers to infection

  • Skin
  • Mucus membrane
  • Lysozymes in tears
  • Acid in stomach
• Skin


  • Physical barrier with fatty acids, and commensals to help keep the pathogens at bay
• Mucus membrane barriers


  • Mucus
  • Cilia
  • Commensals
  • Low pH in the Vagina
• Lysozymes in tears and acid in stomach

  • Physical and chemical berries to infection
• Molecular defences of our bodies

  Humoral factors
• There is need to discriminate between self and non-self-cells, molecules, and substances
• Pattern recognition receptors (PRRs)


  Located on host cells such as macrophages, neutrophils, dendritic cells, allow for identification of pathogens
• Toll-like receptors


  • Located on the surface of the membrane, they are evolutionarily conserved
• Toll-like receptors in humans

  • 10 Toll-like receptors, each has its own store of pathogen-associated molecular patterns
• PAMPS


  Parts on pathogen that gets recognized by the host by a lock and key mechanism
• NOD-like receptors


  Intracellular pattern recognition receptors
• NOD


  Nucleotide-binding oligomerization domain
• Pathogen-associated molecular patterns


  Mannose-rich oligosaccharides
• Leucocytes (white blood cells)

  • Lymphocytes (B, T and NK)
  • Monocytes (tissue macrophages)
  • Granulocytes
  • Tissue mast cells
• Granulocytes

  • Neutrophils
  • Eosinophils
  • Basophils
• Macrophage function

  • Phagocytosis and activation of bactericidal mechanisms, Antigen presentation
• Dendritic cell function

  • Antigen uptake in peripheral sites, Antigen presentation
• Neutrophil's function

  • Phagocytosis and activation of bactericidal mechanisms
• Eosinophil's function

  • Killing of antibody-coated parasites
• Basophil's function

  • Promotion of allergic responses and augmentation of anti-parasitic immunity
• Mast cell's function

  • Release of granules containing histamine and active agents
• Dendritic cells form the bridge between innate and adaptive immune responses
• Dendritic cells


  • Present in many locations, move around lymphatic system (specialized antigen presenting cells), have a big surface area
• Mechanisms of cellular defences

  • Phagocytosis by neutrophils and macrophages
  • Extracellular killing
  • Inflammation
• Consequences of phagocyte dysfunction or insufficiency

  • Bacterial infections (staphs, pseudomonas)
  • Fungal infections (Aspergillus, Candida)
  • Recurrent infections