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Specific Defenses of the Host

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					Specific Defenses of the Host
       Microbiology 2314
          Innate Resistance
• An individual’s genetically predetermined
  resistance to certain diseases
• Ex. Resistance to AIDS due to a gene
Humans Have Resistance to a Number of
         Different Things
 •   Bacteria      •   Insect Venom
 •   Viruses       •   Transplanted Tissue
 •   Fungi         •   Cancer Cells
 •   Protozoa      •   Diseases
          Individual Resistance
             is Affected By
•   Gender
•   Age
•   Nutritional Status
•   General Health
     Resistance Leads to Immunity
• The ability of the body to specifically counteract
  foreign organisms or substances called antigens.
• Results from the production of specialized
  lymphocytes and antibodies (proteins)
Serology


• Looks at reactions between antibodies and
  antigens
• A specialized branch of microbiology.
• Uses serum samples
               Remember!
 • Antigens provoke an immune response.
 • Antibodies are produced to respond to
   antigens.



Antigens  Antibodies  Protection
                         Types of Immunity
                                        Types of Immunity


                                        Acquired Immunity


          Naturally Acquired Immunity                       Artificially Acquired Immunity
                    (Infection)                                         (Injection)


        Active                  Passive                  Active                    Passive
   Simple Exposure       Transplacental Transfer       Vaccination              Use of Antisera
Lifelong or Short Term         Colustrum              Immunization
                                              Naturally Acquired
                                               Active Immunity
         • Immunity Resulting
           from Infection
         • May be Long Term

                                        Types of Immunity


                                        Acquired Immunity


          Naturally Acquired Immunity                       Artificially Acquired Immunity
                    (Infection)                                         (Injection)


        Active                  Passive                  Active                    Passive
   Simple Exposure       Transplacental Transfer       Vaccination              Use of Antisera
Lifelong or Short Term         Colustrum              Immunization
                                                                                             Naturally Acquired
  • Mother to Fetus                                                                          Passive Immunity
  • Transplacental
    Transfer
  • Colostrum
  • Few Months Duration

                                        Types of Immunity


                                        Acquired Immunity


          Naturally Acquired Immunity                       Artificially Acquired Immunity
                    (Infection)                                         (Injection)


        Active                  Passive                  Active                    Passive
   Simple Exposure       Transplacental Transfer       Vaccination              Use of Antisera
Lifelong or Short Term         Colustrum              Immunization
  Artificially                                                    Types of Immunity


                                                                  Acquired Immunity

   Acquired                         Naturally Acquired Immunity
                                              (Infection)
                                                                                      Artificially Acquired Immunity
                                                                                                  (Injection)

Active Immunity                   Active
                             Simple Exposure
                                                          Passive
                                                   Transplacental Transfer
                                                                                   Active
                                                                                 Vaccination
                                                                                                             Passive
                                                                                                          Use of Antisera
                          Lifelong or Short Term         Colustrum              Immunization


 • Immunity Resulting
   from Injection
   (Vaccination)
 • Attenuated Vaccines
 • Inactivated Vaccines
 • Killed Vaccines
 • Toxoid Vaccines
Artificially Acquired Passive Immunity

     • Humoral Antibodies
       Acquired By Injection
     • Lasts for Few Weeks
     • Antisera
                                        Types of Immunity


                                        Acquired Immunity


          Naturally Acquired Immunity                       Artificially Acquired Immunity
                    (Infection)                                         (Injection)


        Active                  Passive                  Active                    Passive
   Simple Exposure       Transplacental Transfer       Vaccination              Use of Antisera
Lifelong or Short Term         Colustrum              Immunization
Gel Electrophoresis is Used to
    Check for Antibodies

Albumen

Alpha

Beta                     Globulins

Gamma
By taking advantage of
distinct physical
characteristics of
different polypeptide
species such as size,
electrical charge, and
shape, a complex
mixture of proteins can
be resolved
electrophoretically by
applying the sample to a
gel matrix in the
presence of an electric
current.
How Does This Work?
         • A charged protein will
           migrate in an electric field
           relative to its net charge.
         • However, as the molecule
           migrates through the gel
           matrix in response to the
           electric current, its mobility
           will be retarded as a
           function of the size and
           shape of the protein by the
           sieving effect of the gel
           matrix.
Antibodies are found in the gamma fraction of the
 serum and are termed serum globulin or gamma
                    globulin
Albumen




 Alpha Beta Gamma
Normal Values
Total protein:      6.4 to 8.3 g/dL
Albumin:            3.5 to 5.0 g/dL
Alpha-1 globulin:   0.1 to 0.3 g/dL
Alpha-2 globulin:   0.6 to 1.0 g/dL
Beta globulin:      0.7 to 1.2 g/dL
Gamma globulin:     0.7 to 1.6 g/dL
Decreased total protein may indicate:
• Malnutrition
• Nephrotic syndrome
• Gastrointestinal protein-losing enteropathy

Increased alpha-1 globulin proteins may indicate:
• Chronic inflammatory disease (for example,
  rheumatoid arthritis, SLE)
• Acute inflammatory disease
• Malignancy

Decreased alpha-1 globulin proteins may indicate:
• Alpha-1 antitrypsin deficiency
Increased alpha-2 globulin proteins may indicate:
• Acute inflammation
• Chronic inflammation

Decreased alpha-2 globulin proteins may indicate:
• Hemolysis

Increased beta globulin proteins may indicate:
• Hyperlipoproteinemia (for example, familial
  hypercholesterolemia)
• Estrogen therapy

Decreased beta globulin proteins may indicate:
• Congenital coagulation disorder
• Consumptive coagulopathy
• Disseminated intravascular coagulation
Increased gamma globulin proteins may indicate:
• Multiple myeloma
• Chronic inflammatory disease (e.g., rheumatoid
  arthritis, SLE)
• Hyperimmunization
• Acute infection
• Waldenstrom's macroglobulinemia
• Chronic liver disease
Normal




Increased
Gamma
Globulin
                Albumen
• Albumin is synthesized by the liver using
  dietary protein.
• Its presence in the plasma creates an
  osmotic force that maintains fluid volume
  within the vascular space.
• A very strong predictor of health; low
  albumin is a sign of poor health and a
  predictor of a bad outcome.
     Low Albumen Can Indicate
•   Dehydration
•   Hypothyroidism
•   Chronic debilitating diseases
•   Malnutrition - Protein deficiency
•   Dilution by excess H2O (drinking too much water, which
    is termed “polydipsia,” or excess administration of IV
    fluids)
•   Kidney losses (Nephrotic Syndrome)
•   Protein losing-enteropathy (protein is lost from the
    gastrointestinal tract during diarrhea)
•   Skin losses (burns, exfoliative dermatitis)
•   Liver dysfunction (the body is not synthesizing enough
    albumin and indicates very poor liver function)
Our Immunity is Expressed Via
 Two Different Mechanisms




 Humoral and Cell Mediated
Humoral Immunity = Antibodies

• Found in Body Fluids
• Involves Specialized Lymphocytes Called B
  Cells that Produce Antibodies
• Produced in Response to a Specific Antigen
• Defend the Body Against Bacteria, Viruses,
  and Toxins in Blood Plasma and Lymph
  (Extracellular Presence)
An Antibody Molecule is shaped like the Letter Y and has
TWO Identical ANTIGEN BINDING SITES that precisely
fit the shape of a ParticularAntigen. Lock and Key.

These sites allow each Antibody to bind to TWO Antigens.
By binding to two
antigens, antibodies
make antigens clump
together.
(AGGLUTINATION)
• The clumped
  Antigens are not
  active.
• Macrophages
  ENGULF and
  DESTROY the
  Clumped Antigens..
• Bone Marrow Stem Cells (Plasma Cells) Give
  Rise to B-Cells
• Liver in Fetus Does Same
• B-Cells Migrate to Lymph Nodes
• Recognition Process Occurs In Which a Mature
  B-Cell will Recognize an Antigen with Antigen
  Receptors and produce
  antibodies.
                              Cell-Mediated
                                Immunity

• Involves Specialized Lymphocytes Called
  T-Cells arising from the Thymus Gland
• No Antibody Production is Involved
• Protect the Body from
  –   Intracellular bacteria and viruses
  –   Multi-cellular parasites
  –   Transplanted tissue
  –   Cancer cells
T-Cells Attacking
a Cancer Cell
       Review and Remember
• Antigen – (Also Called an Immunogen) A
  chemical substance that causes the body to
  produce either specific antibodies or
  sensitized T-cells.
• Are foreign substances
• Can be microbial or non-microbial
Non-Microbial Antigens
    •   Pollen
    •   Egg White
    •   Transplanted Tissue
    •   Peanut Butter
  Most Antigens are Components
      of Invading Microbes


• Proteins           Large Polysaccharides
                          - Cell Walls
  - Nucleoproteins
                          - Capsules
  - Lipoproteins          - Flagella
  - Glycoproteins         - Toxins
     The Nature of Antibodies
An antibody (also called an Immunoglobulin)
is a protein produced by B cells in response to
the presence of an antigen and is capable of
combining specifically with that antigen.
          Antibody Structure

• Monomer Single
  Bivalent Antibody
• Four Polypeptide
  Chains
• Two Heavy Chains
• Two Light Chains
• Variable Region
• Constant Region
• Y or T shaped
The Variable Region forms the tips of the monomer.
The constant regions form the Base and the Stem Region
The Stem Region can Attach a Host Cell or Complement
(The Stem is called Fc as it is a fragment that crystallizes when cold)
       Immunoglobulin Classes


•   IgG / Monomer
•   IgM / Pentamer
•   IgA / Dimer
•   IgD / Monomer
•   IgE / Monomer
       IgG
                                          Y
• Prevalent / 75% - 80% in Body Fluids
  (Serum)
• Provide Naturally Acquired Passive
  Immunity
• Neutralize Toxins, Fight Bacteria and
  Viruses
• Participate in Complement Fixation
• Enhance Phagocytosis
• Cross Blood Vessels
• Cross Placenta (Unique to IgG)
         IgM                     Y
• Five Monomers, Largest
• Found in Blood and Lymph
• Involved in Agglutination in
  Blood Typing
• Participate in Complement
  Fixation
• Compose 5-10%
• Can’t Move Freely / Stay in
  Blood Vessels
• First Responder to Infection
• Short Lived
             IgA
• Dimers / Compose 10-15%
• Protect Mucosal Surfaces
  from Pathogens / Saliva,
  Tears, Blood
• Repel Respiratory Infections
• Present Colostrums
• Protect Infants / GI
  Infections
• A small number of people
  do not make IgA antibodies.
IgD

      • Monomer
      • IgD antibodies are
        found in small
        amounts primarily in
        the tissues that line the
        belly or chest. How
        they work is not clear.
      • Compose 0.2%
            IgE

• Binds to Mast Cells and Basophiles
• Found in the Lungs, Skin, Mucus Membranes / 0.002%
• Protects the host against invading parasites causing the
  body to react against foreign substances such as pollen,
  fungus spores, and animal dander.
• They may occur in allergic reactions to milk, some
  medicines, and some poisons.
IgE antibody levels are often high in people with allergies
resulting in release of histomine (redness or hives)
            Antibody Titer
• The antibody level in the blood is a
  reflection of the body's past experience or
  exposure to an antigen, or something that
  the body does not recognize as self.
         Immunological Memory
• Titers for IgM usually rise abruptly at the time of
  infection–acute phase and fall slowly; during the
  'convalescent' phase,
• IgG then increases and stays elevated for life.
               Apoptosis
• Programmed Cell Death that Unneeded
  Lymphocytes Undergo
• 100 Million Daily Produced and Destroyed
• Shrink / Ingested
• Violent Death (Bursting) Triggers
  Inflammation

				
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posted:5/25/2011
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