innate immune response

• immunology history

  • Athens plague, only recovered people could nurse the sick 430BC
  • China/Aztecs, inhaled crusts of smallpox provided to protect 15th century
  • Cowpox, provides immunity against smallpox, vaccination discovered 18th century
  • attenuated rabies virus used as vaccine, improved vaccine
  • 1980, smallpox eradicated by vaccination
• 25 Nobel Laureates in immunology
• immune system made of

  • lymphatic system, blood organ systems
  • bone marrow, thymus, lymph nodes, spleen organs
  • innate and adaptive cells
  • antibodies, cytokines, complement molecules
• fighting infection

  • stop pathogen entering
  • if enters, flush it out, kill it, control it
  • once defeated, remember
• skin prevents pathogens entering by

  • dead cells prevent bacteria
  • sebaceous gland made of fatty acid, lactic acid, low pH
  • skin is dry, lack of nutrients for bacteria
• tight junctions stop 


  ingested antigens passing into the body
• mucosal surfaces

  • slippery
  • cilia move pathogen away
  • mucus traps, then sheds them from body
• mechanical barriers

  • skin
  • tight junctions
  • mucus
• physiological barriers

  • pH and environment
  • chemical mediators
• pH is low in stomach, to kill pathogens
• microbiota out compete pathogens for


  nutrients
• chemical mediators include

  • anti-microbial peptides (defensins damage pathogens)
  • anti-microbial proteins (lysozymes in tears)
  • cytokines (interferons induce anti-viral state in cells)
  • complement (M-A-C lyses bacteria)
• innate is 


  inherent
• adaptive is 


  learned
• innate immune system has mechanical and physiological barriers
• parasite can avoid innate immune system by

  • hook on to avoid being flushed
  • burrow through skin
• Granulocytes


  White blood cells involved in fighting infections: Neutrophils, Eosinophils, Mast Cells, Basophils
• Phagocytes


  Cells that engulf and digest foreign particles and cells: Neutrophils, Macrophages, Dendritic cells
• Lymphocytes


  Cells that recognize and respond to specific antigens: ILCs, Natural Killer cells
• phagocytes means eating cells
• granulocytes are 


  granule containing cells
• four signs of inflammation

  1. heat
  2. redness
  3. swelling
  4. pain
• 5th sign of inflammation could be

  stop of use of information
• stages of inflammatory response

  • chemokine release, neutrophils recruited, histimine released from mast cells
  • clotting and complement cascades are activated
  • neutrophils secrete chemokines, recruit monocytes from blood
  • phagocytosis of pathogens
  • macrophages migrate and secrete IL-1 and TNF-alpha to recruit lymphocytes, monocytes and neutrophils
• what is important chemokine in recruitment of neutrophils to site of infection

  IL-8
• systemic acute-phase response

  • fever-speeds up phagocytosis
  • leukocytosis- WBCs production increases
  • acute phase proteins produced by the liver
• complement system is 


  group of serum proteins performing critical defence against pathogens
• acute phase response is stimulated by the pro-inflammatory cytokines IL-6 and TNF-alpha
• complement functional categories

  • initiators
  • enzymes
  • opsonins
  • anaphylatoxins
  • membrane attack proteins
  • complement receptors
  • regulatory proteins
• initiators 


  bind pathogens components or antibodies
• how does body sense infection

  innate immune system detects molecules from pathogen associated molecular patterns (PAMPs) using pattern recognition receptors
• phagocytosis

  labels

  A) PAMPs

  B) PRR

  C) pseudopodia

  D) phagosome

  E) lysosome

  
• 2 killing mechanisms

  • oxygen dependent
  • oxygen independent