Applications of the Immune System

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Chapter 17

• Applications of the Immune System

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Jenners vaccine field of immunology

• Immunology the study of the bodys defense
  against foreign invasion
• Tested the hypothesis that cowpox Vaccinia virus
  provided protection against smallpox
• Collected pus from a milkmaids cowpox lesion
• Infected a boy with the cowpox pus
• Boy developed cowpox
• Then he infected the boy with smallpox
• The boy was immune

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Principles of Immunization

• Natural acquired immunity
• Immunization mimics the same natural events
• Artificial Active immunity
• Natural Passive immunity
• IgG antibodies cross the placenta and protect the
  fetus
• Breast feeding transfers IgA antibodies

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Principles of Immunization

• Artificial Passive immunity
• Antiserum
• Protective antibodies
• Antitoxin
• Protects against a toxin
• Examples tetanus immune globulin (TIG), rabies
  immune globulin (RIG)
• Given after exposure but before disease develops

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Figure 17.5 The characteristics of immunity
produced by active immunization and passive
immunotherapy
Passiveimmunotherapy
Injection
Activeimmunization
Antibody (IgG, IgM) concentration (titer)
Boosters
Initialinoculation
Time
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Vaccine and immunization

• A phenomenon that occurs when a large portion of
  a population is immune or vaccinated against a
  disease
• Responsible for the dramatic decline of childhood
  diseases

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Figure 17.1 Effect of immunization-overview
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Figure 17.3 The CDC's recommended immunization
schedule for the general population
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Immunization

• Vaccine types
• Attenuated (live) vaccines
• Can result in mild infections
• Active microbes stimulate a _________________
  response
• Can provide contact immunity
• Infect others around them
• Caution Modified microbes may retain enough
  residual virulence to cause disease
• Pregnant women
• HIV patients

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Immunization

• Vaccine types
• Whole-agent vaccines
• Deactivated whole microbes
• Subunit vaccines
• Fragments of microbes
• Both safer than live vaccines
• Due to lack of replication microbes and fragments
  ____ ____________________________________________
• _____________________________________________
• Booster shots often needed

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Immunization

• Vaccine types
• Combination vaccines
• Administration of antigens from several pathogens
• MMR- measles mumps rubella

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Immunization

• Vaccine types
• Toxoid vaccines
• Chemically or thermally modified toxins used to
  stimulate immunity
• Useful for some bacterial diseases
• Tetanus and diphtheria
• Stimulate antibody-mediated immunity
• Require multiple doses because they possess few
  antigenic determinants

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• Vaccines against anthrax, cholera, plague,
  tuberculosis
• Are available but limited to special populations
• Military
• Laboratory personnel

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Immunization

• Vaccine manufacture
• Mass-produce many vaccines by growing microbes in
  culture vessels
• Viruses are cultured inside chicken eggs
• Individuals with egg allergies must avoid some
  vaccines

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Immunization

• Active Immunization
• Vaccine safety
• Problems associated with immunization
• Mild toxicity most common
• Fever and pain at injection site
• Risk of anaphylactic shock
• Allergic reaction- due to egg proteins or
  preservatives
• Residual virulence from attenuated viruses
• Occasionally cause disease
• Oral poliovirus vaccine in late 1990s caused
  clinical polio in 1 out of 2 million
• An inactivated polio vaccine is now used!
• Allegations that certain vaccines cause autism,
  diabetes, and asthma
• Research has not substantiated these allegations

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To vaccinate or not?

• CDC and FDA conclude that the problems associated
  with immunization are far less serious than the
  suffering and death that would occur if we
  stopped immunizing people.

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Immunology Applications

• Labeled Antibody Test
• Uses antibody molecules linked to some label
  that enables them to be easily detected
• Used to detect either antigens or antibodies

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Immunology Applications

• Labeled Antibody Test
• Fluorescent antibody tests
• Use fluorescent dyes as labels
• Fluorescein is one dye used in these tests
• Fluorescein-labeled antibodies used in two types
  of tests
• Direct fluorescent antibody tests identify
  presence of antigen in tissue
• Indirect fluorescent antibody tests identify the
  presence of antibody from an individuals serum

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Figure 17.11 The direct fluorescent antibody test
Straight forward test flood specimen with
labeled antibodywaitwash and examine.
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Immunology Applications

• Labeled Antibody Test
• ELISA
• Enzyme-linked immunosorbent assay
• Uses an enzyme as the label
• Reaction of enzyme with its substrate produces
  colored product
• Commonly used to detect presence of antibodies in
  serum

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Immunology Applications

• ELISA
• Direct
• Used to detect a given antigen
• Rapid Group A strep tests and home pregnancy kits
• Indirect
• Used to detect the presence of an antibody in a
  sample
• Used to test donated blood for antibodies against
  HIV

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Figure 17.13 The enzyme-linked immunosorbent
assay (ELISA)
Antigen is attached to well in plate.
A protein such as gelatin is added to block the
uncoated surface.
Patient serum is added complementary antibody
binds to antigen.
Enzyme
Anti-antibody
Enzyme-linked anti-antibody is added and binds to
bound antibody.
Substrate
Colored product
Enzymes substrate is added, and reaction
produces a visible color change.
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Figure 17.14 An antibody sandwich ELISA-overview
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Immune Testing

• Labeled Antibody Test
• ELISA
• Advantages of the ELISA
• Can detect either antibody or antigen
• Can quantify amounts of antigen or antibody
• Easy to perform and can test many samples quickly
• Plates coated with antigen and gelatin can be
  stored for later testing

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Exam 3 review

• Ch 13
• Why are viruses viroids and prions considered to
  be acellular particle's?
• What are the differences between the lytic and
  lysogenic cycles of viral replication?
• What is induction?
• What are the steps in animal virus replication?

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• How are viruses classified?
• What types of cells can viruses infect?
• What accounts for the specificity of viral
  infection?

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• The phenomenon of transduction (a type of
  horizontal gene transfer) is associated with
  which of the stages of a bacteriophage infection
  cycle?
• Know what each of the 3 acellular particle are
  composed of and be able to apply that knowledge
  to critical thinking questions.

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Chapter 14

• Understand the different reservoirs for
  infectious diseases
• Know the different portals of entry and exit
• Understand the basic stages of infectious
  diseases
• Know the modes of disease transmission

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• Be able to differentiate between the following
  endemic, sporadic, epidemic, pandemic, outbreak.
• Understand the factors that influence the
  development of nosocomial infections.

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Chapter 15

• What is meant by nonspecific immune response? 
• Understand the bodys first line defenses
• Understand the role of skin in innate immunity
• Understand the role of mucous membranes in innate
  immunity
• Understand the role of normal microbiota in
  innate immunity

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• When do the second line defenses begin their
  protective roles?
• Understand the steps of phagocytosis
• Understand the signs and outcomes of inflammation
• Understand the basics of the complement system
  and the 3 outcomes
• How does fever form and why is fever thought to
  be beneficial? Why harmful?

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Chapter 16

• Compare and contrast innate immunity and adaptive
  immunity
• Who are the players in humoral responses?
• Differentiate between the 2 types of humoral
  responses

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• Describe the 5 outcomes of antibody antigen
  binding complexes.
• Understand the differences in the 3 types of
  antigens?
• Differentiate between the 5 classes of antibodies

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• Who are the players in cell mediated responses?
• What is the outcome of a cell mediated response?
• Understand the process of CTL activation