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Immunity

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Tears, saliva, urine wash away pathogens from surface or body or dilute invading ... Response time = 3-14 days; disease symptoms develop; SLOW. Antibody production ... – PowerPoint PPT presentation

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Title: Immunity


1
Immunity
  • Innate Adaptive

2
Immunity
  • Innate response to attack is always the same
  • Mechanical mechanisms
  • Chemical mediators
  • Cellular response
  • Inflammatory response
  • Adaptive response to attack improves with each
    exposure
  • Specificity
  • Memory

3
Innate immunity
  • Mechanical mechanisms
  • Skin mucus membranes form physical barriers to
    prevent entry
  • Tears, saliva, urine wash away pathogens from
    surface or body or dilute invading army of
    pathogens

4
Innate immunity
  • Chemical mediators
  • Some prevent entry to cells, kill bacteria,
    produce inflammation
  • Complement proteins
  • 20 in plasma
  • normally inactive activated by combining with
    parts of bacterial cells or antibodies
  • Leads to chain rxn activation of neighboring
    compliments inflammation, phagocytosis, or lysis

5
Innate immunity
  • Chemical mediators
  • Interferons protect against viral infection
  • Virus-infected cells place interferons on their
    surface (SOS signal)
  • These bind to neighboring cells stimulate
    neighbors to produce antiviral proteins
  • Intiviral proteins inhibit production of new
    viral RNA
  • Some interferons activate macrophages and NKC

6
Innate immunity
  • Cellular mechanisms
  • WBC derivatives are most important cellular
    components
  • Attracted to invading bacteria and microorganisms
    through chemotaxis
  • Phagocytic cells (who are these?)
  • Inflammatory cells (and these?)
  • Natural Killer Cells (NKC)

7
Innate immunity
  • Phagocytic cells
  • Neutrophils
  • Small first to enter infected tissue from blood
    ingest, then die --gt pus accumulation
  • Macrophages
  • Monocytes leave blood enlarge arrive after
    neutrophils do most eating cleanup
  • Also hang out at entry points (gate-keepers)

8
Innate immunity
  • Natural Killer Cells (NKC)
  • 15 of all lymphocytes are NKC
  • Recognize tumor cells or virus-infected cells
    (generalist killers)
  • No memory non-specific
  • Kill via chemical release (cell membrane lysis)

9
Innate immunity
  • Inflammatory cells activated through innate or
    adaptive immunity release histamine such
  • Basophils
  • Motile WBC enter infected tissue
  • Mast cells
  • Non-motile Located in CT at points of entry
  • Eosinophils
  • Release enzymes that reduce inflammation (control)

10
Innate immunity
  • Local inflammation
  • Redness, heat, swelling caused by increased blood
    flow and vascular permeability
  • Chemicals and swelling activate pain receptors
    (what type of receptors are these?)
  • Systemic inflammation
  • Red marrow increases neutrophil production
  • Pyrogens stimulate fever by increasing heat
    production conservation
  • Vascular permeability increases (why?)

11
Adaptive immunity
  • Lymphocytes
  • Origin development
  • Activation multiplication
  • Antibody-mediated
  • Cell-mediated

12
Adaptive immunity
  • Antigens stimulate adaptive immune response
  • Self
  • Foreign
  • MHC molecules display antigens
  • Lymphocytes
  • Origin development
  • Activation multiplication
  • Types of Adaptive Immunity
  • Antibody-mediated
  • B cells produce cells that make antibodies
  • Cell-mediated
  • T cells cytotoxic helper T cells

13
Antigens
  • Foreign
  • Components of bacteria, viruses, and their
    chemical byproducts
  • Pollen, animal hair, foods produce allergic
    response (overreaction of immune system)
  • Self
  • Produced by our bodies
  • Recognize tumor antigens

14
Cell Development
  • Red marrow produces
  • Pre B-cells released into bloodstream and
    migrate to lymph organs
  • Pre T-cells migrate to thymus mature there
  • Mature T-cells migrate to lymph organs

15
B T-cells
  • Contain antigen receptors in their cell membranes
  • We each have thousands of different populations
    of B T-cells, each with unique antigen
    receptors
  • Cells are stimulated by binding of antigens to
    their unique receptors

16
Activation multiplication
  • Macrophages present antigens
  • Phagocytize invaders, process and display
    antigens (with help of MHC molecules)
  • MHC/Antigen complex binds to receptors on B or
    T-cells
  • T-cells auto-stimulate
  • Produce cytokines (peptides e.g. interleukin)
    that up-regulate growth division

17
B cell activation
  • Antibody-mediated
  • B-cells can also phagocytize process antigens
  • same antigen that stimulated a Th
  • Th binds to B-cell
  • Interleukins are produced
  • stimulate B-cell division proliferation
  • Daughter (plasma) cells produce antibodies

18
Effects of Antibodies
  • Direct
  • Antibodies bind antigens inactivation
  • Indirect
  • Activate Complement cascade
  • Inflammation (mast cells and basophils release
    histamine)
  • Chemotaxis (attracts white blood cells)
  • Phagocytosis or lysis (macrophage eats antibody
    antigen

19
Direct
  • Antibody binds antigens
  • Single
  • Or several

20
Indirect
  • Activates complement cascade
  • Antibody attaches to mast cell or basophil
    triggers inflammation response when antigen binds
    to it

21
Indirect
  • Antibody binds to antigen, then to macrophage
  • Macrophage eats the whole complex

22
Antibody production
  • Differs following first and second exposure to
    antigen
  • First exposure primary response
  • B-cells bind antigen produce plasma cells
    (produce antibodies) and memory B-cells
  • Response time 3-14 days disease symptoms
    develop SLOW

23
Antibody production
  • Differs following first and second exposure to
    antigen
  • Second exposure secondary response
  • Memory cells quickly produce plasma cells and
    antibodies
  • Time to antibody production is less
  • More plasma cells antibodies produced
  • RAPID response, no disease symptoms immunity

24
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25
Cell-mediated immunity
  • Cytotoxic T cells (Tc)
  • Effective against viruses, bacteria involved in
    graft rejections
  • Infected cells display antigens, and Tc binds to
    MHC/antigen combo
  • Stimulates production of more Tc
  • Costimulation by Th which were stimulated by
    macrophage display of antigens

26
Cell-mediated (Tc)
27
T cell responses
28
Show Immune Response
29
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30
Acquired immunity
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