Innate vs adaptive immunity

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Innate vs adaptive immunity

• Mike Kemeny
• Professor of Immunology,
• GKT School of Medicine and Dentistry,
• Kings College, London, UK

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Textbooks
Janeway Travers Immunobiology   Abbas
Lichtman Pober Cellular Molecular
Immunology   Peakman Vergani Basic and Clinical
Immunology Various Roitt textbooks  
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Useful web sites and reading   1. Immunologic
Diseases http//www.mic.ki.se/Diseases/c20.html
excellent resource A comprehensive list of links
to websites related to immune diseases.   2. The
PathoPlus Page http//pathoplus.com/newpage7.htm G
ood introductory lectures on cells of the immune
system and inflammation.   3. The Macrophage Home
Page http//www.path.ox.ac.uk/sg A recently
updated introduction to the cells of the
mononuclear phagocyte family.   4. Antigen
Presentation http//www.ultranet.com/jkimball/Bio
logyPages/A/AntigenPresentation.html A nice
introduction to antigen presentation, part of
Kimball's Biology Pages.   5. Clinical and basic
Immunology tutorials http//www.ozemail.com.au/da
vidful/Net_Path_Immunology/tutes.html
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What is the immune system for

• Protect against pathogens
• Eliminate damaged or malignant cells

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Role of the immune system is to protect from
Virus Influenza Polio mellitus

• Parasites
• Tapeworms
• Malaria
• Helminths

Bacteria Tubercule bacillus Staphylococci
Fungi Candida albicans
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Innate immunity

• Immediate protection
• Low specificity broad reactivity
• Important for first exposure

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The innate immune system

• Physicochemical barriers Skin, mucus, cilia
• Secreted agents Lysozyme, acidic pH, saliva,
  urine
• Protective organisms Commensal bacteria
• Phagocytic cells Macrophages,
  Neutrophils secrete free radicals
  (superoxide and cationic proteins)
• Natural Killer (NK) cells

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Cell wall proteins
Bacterial DNA
DANGER!
Bacteria
Activated dendritic cell (DC)
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• Features of pattern recognition
• Conserved receptors and ligands
• Invokes same response in immune system
• You are born with it (innate)

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Comparison of Innate and Adaptive immune system
Innate
Adaptive
Receptors/ ligands
Diverse
Conserved
Modulated (ie memory)
Invariant
Grade of response
Immature at birth
Age
Fully mature at birth
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The innate immune system

• Ligands that bind pathogens Pattern recognition
  receptors (Toll like receptors, mannose
  receptors)
• Secreted agents Interferon (IFN) a, b, g
• Complement activation Alternative pathway
  - secretion of anaphylatoxins C3a and
  C5a

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The adaptive immune system

• Later protection
• High specificity
• Important for lasting protection

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Components of the adaptive immune system

• Molecules Antibody
• Complement
• Cytokines
• Cells Lymphocytes (T B cells)
• Natural Killer cells
• Monocytes/Macrophages
• Dendritic cells
• Neutrophils Eosinophils
• Basophils/Mast cells

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Cells of the immune system

• B cells
• T cells
• NK cells
• Monocytes/macrophages
• Neutrophils
• Eosinophils
• Basophils/Mast cells

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Origin of cells involved in the immune response
Myeloid progenitor
Haemopoietic stem cell
Monocyte

Lymphocyte progenitor
Macrophage
Basophil
Neutrophil
B cell
Thymus
NK cell
Mast cell
Eosinophil
CD4 T cell
CD8 T cell
Plasma cell
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What is the immune system

• A collection of cells and molecules that protect
  the body against infection, malignancy and
  damaged cells

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Antigen

• A molecule that can be recognised by the immune
  system
• Usually foreign to the body although our own
  molecules can serve as antigens
• Proteins eg Grass pollen, egg albumin. bacterial
  endotoxin,
• Haptens eg Nickel salts which bind to proteins

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Antibody

• Specialised molecules that recognise and bind to
  antigens
• All antibodies are immunoglobulins

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B Lymphocytes

• 10 of blood mononuclear cells
• Make immunoglobulin (antibody)
• Each B cell only makes antibody of one
  specificity
• B cells that make antibody are called plasma cells

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Immunoglobulin