Transcript Chapter 17 Applications of the Immune System

Chapter 17
Applications of the Immune System
Jenner’s vaccine – field of immunology
• Immunology: the study of the body’s 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
Principles of Immunization
• Natural acquired immunity
–
• Immunization mimics the same natural events
– Artificial Active immunity
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– Natural Passive immunity
–
–
– IgG antibodies cross the placenta and protect
the fetus
– Breast feeding transfers IgA antibodies
–
Principles of Immunization
• Artificial Passive immunity
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–
– Antiserum
– Protective antibodies
– Antitoxin
– Protects against a toxin
– Examples: tetanus immune globulin (TIG), rabies
immune globulin (RIG)
– Given after exposure but before disease develops
Antibody (IgG, IgM) concentration (titer)
Figure 17.5 The characteristics of immunity produced by active immunization and passive immunotherapy
Passive
immunotherapy
Injection
Boosters
Initial
inoculation
Time
Active
immunization
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
Figure 17.1 Effect of immunization-overview
Figure 17.3 The CDC's recommended immunization schedule for the general population
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
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 ____
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– Booster shots often needed
Immunization
• Vaccine types
– Combination vaccines
– Administration of antigens from several pathogens
– MMR- measles mumps rubella
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
• Vaccines against anthrax, cholera, plague,
tuberculosis
– Are available but limited to special populations
– Military
– Laboratory personnel
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
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
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.
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
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
Figure 17.11 The direct fluorescent antibody test
Straight forward test: flood specimen with labeled
antibody…wait…wash and examine.
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
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
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
Enzyme’s substrate is added, and reaction produces a visible color change.
Figure 17.14 An antibody sandwich ELISA-overview
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
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?
– How are viruses classified?
– What types of cells can viruses infect?
– What accounts for the specificity of viral
infection?
• 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.
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
• Be able to differentiate between the following
endemic, sporadic, epidemic, pandemic,
outbreak.
• Understand the factors that influence the
development of nosocomial infections.
Chapter 15
• What is meant by nonspecific immune
response?
• Understand the body’s 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:
• 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?
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
• 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
• Who are the players in cell mediated
responses?
• What is the outcome of a cell mediated
response?
• Understand the process of CTL activation