Nonspecific Immunity

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Non-specific Immunity
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First Line of Defense

• Physical barrier on all surfaces of body exposed
  to external world
• What are they?
• Skin
• Mucous membranesnasal, respiratory
• Lining of mouth
• Lining of gut
• Lining of vagina/urethra
• Surface of eye

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Barrier Membranes
Skin
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How do barrier membranes keep bacteria out?

• Chemical barrierantibacterial secretions
• Cellular barriercells tightly packed and
  sloughed off (10B skin cells/day250 g./year)
• Physical barrierthick, mucousy and sticky
  secretions trap bacteria
• Resident microbeshave commensal or mutualistic
  bacteria and fungi that are normally present and
  out-compete potential pathogens

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Second Line of Defense

• Phagocytosis
• Inflammation
• Complement
• Fever
• All work tightly with specific immunity (coming
  next)

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Phagocytosis

• Phagocytes move through blood and lymph and into
  connective tissues (part of inflammation response
  as cells and fluid move out of capillaries into
  surround aleolar tissues--diapedesis)

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• Langerhans cells in skin
• Phagocytes in blood
• Microglial cells in CNS

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Complement

• Group of free proteins in blood that respond to
  antigen/antibody complex (huh?coming soon)
• Cascade of reactions eventually makes
  MACsmembrane attack complexthat bores hole in
  bacterial membrane
• Gram-negative bacteria more susceptible

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Inflammation

• Response to tissue damage from any source (burn,
  cut, pathogen, other??)
• Blood vessels dilate allowing for better delivery
  of nutrients, O2, antibodies, complement, immune
  cells
• Phagocytes (monocytes and neutrophils) migrate
  out of capillaries--diapedesis

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Fever
Trigger not completely understood Muscular
contraction and constriction of skin blood
vessels cause core temperature to rise

• Pluses
• Inhibit microbial growth
• Enhance immune cell performance
• Speed tissue repair

• Minuses
• Malaise
• Body aches
• chills

• Breaking fever or crisis of fever
• body begins to cool by sweating,
• color returns as blood vessels in skin open
• Indicates infection is overcome

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Links to Specific Immunity

• Phagocytosis continues to be common way to kill
  pathogenic cells in both specific and
  non-specific response
• Inflammation works to allow both specific and
  non-specific immune response to accelerate
• Fever also allows for better performance in both
  specific and non-specific function
• Specific immune response and antigen
  presentation further stimulates non-specific
  actions like phagocytosis, complement.

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Great review of Body Defenses or Non-specific
Immunity
http//fajerpc.magnet.fsu.edu/Education/2010/2010_
INDEX.HTM