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Adaptive Immunity Specific Defenses of the host

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					Adaptive Immunity: Specific
   Defenses of the host
           Ch 17
• Innate resistance
• Immunity: ability of the body to resist
  pathogens
  – Due to production of specific lymphocytes and
    antibodies
• Acquired immunity
  – Naturally – active immunity – get it, get over it
  – Passive immunity – Mother to child, AB from
    mother (short term)
Dual Nature of Adaptive Immunity




                             Figure 17.8
Dual Nature of Adaptive Immunity
• T and B cells develop from stem cells in red
  bone marrow
• Humoral immunity
  – B cells mature in the bone marrow
     • Chickens: Bursa of Fabricius
  – Due to antibodies
• Cellular immunity
  – Due to T cells
  – T cells mature in the thymus
      ANIMATION Humoral Immunity: Overview
    Artificially acquired immunity

• Vaccination
• Antiserum
• Gamma globulin (IgG purified)
• Antigen, anything that can cause an
  immunological response
  – Examples
     Humoral vs.. cell mediated
          immunity
• Humoral is serum immunity
• Cell mediated depends on T cells
          Antibody Structure

• The monomer is bivalent
• 4 ppt chains, 2 light and 2 heavy
• All contain a V region where antibody
  binding occurs
• Y or T shaped know where ab binds, know
  constant region.
• Fc or constant region binds to host cell or
  complement.
Epitopes
Haptens: example penicillin




                              Figure 17.2
   Classes of Immunoglobulin
• IgG serum, passive immunity, neutralize,
  precipitate, opsonize
• IgM 5monomers on a chain, agglutination
  and complement
• IgA monomer in serum, dimmers in
  mucus, protects outer surfaces.
• IgD antigen receptors on B cells
• IgE antigen receptors on mast cells and
  basophiles.
• Apoptosis: programmed cell death,
  Lymphocytes that are no longer needed
  destroy themselves.
• Clonal selection: during fetal
  development, self reacting AB is
  destroyed. During sickness more AB is
  produced (will review later)
Types of WBC
Clonal Selection and differentiation of
B cells
      Results of antigen binding
•   Neutralize
•   Opsonizaiton
•   Agglutination
•   Fixing complement
•   Precipitation
     Immunological memory
• Ab titer
• Plasma cells
• Memory cells
      Monoclonal Antibodies
• Immortal cells that produce an antibody
  that binds to one haptin.
Production of Monoclonal
     AB (fig 18.2)
       Antibodies can now be
           manufactured
• Used to tread
  diseases like cancer
• How are antibodies
  treated so that they
  do not produce an
  immune response?
All of the previous activities are due
              to B cells.
     T cells and cell mediated
              Immunity
• Differentiate in the thymus gland (and
  others)
• Classified by cell surface receptors (CD4)
• Binds to antigen and APC by MHC
       Practical applications of
        Immunology (ch 19)
• Vaccines
  – Heard immunity: if > 85% are immune to a
    disease, the pathogen has difficulty spreading
• Types
  – Attenuated whole agent – non pathogenic
  – Inactivated whole agent – dead
  – Toxoids – inactivated toxin
  – Subunit vaccine –purified protein
  – Conjugated vaccine
  – DNA vaccine – MHC1 associated responses
        How to make vaccines
•   Animals
•   Cell culture
•   Chick embryos
•   Recombinant vaccines are much safer
Disorders of the Human immune
             system
                   Defects
•   Hay fever
•   Transplant rejection
•   Autoimmunity
•   Infection
•   carriers
           Hypersensitivity
• Rx that lead to tissue damage
• Occur when person is sensitized
• 4 types
           Autoimmune disease
• From loss of self tolerance
• Self tolerance occurs during fetal development
    – Clonal deletion
    – Clonal anergy
•   Graves disease
•   Myasthenia gravis
•   Systemic lupus
•   Rheumatoid arthritis
•   Hashimotas disease
•   Insulin dependent diabetes
            Types of T cells
• Classified by certain glycoproteins on
  surface (clusters of differentiation (CD))
• Th –T helper-CD4
  – Recognise an antigen presented on the
    surface of a macrophage and activate it.
• Tc – Cytotoxic T cells –CD8
  – When activated by cytokines from the Th cell
    will change to kill self altered cells
• Tr – Regulatory T cells – (turn down
  immune response)
      Cytotoxic T cells are
transformed into CTL’s by a cell
       with markers on it.
The MHC antigen complex induces a toll-like
receptor
Organisms like
large paracites
that are too
large for
ingestion by
phagocytic cells
must be
attacked
externally

				
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posted:10/11/2011
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