Practical Applications of Immunology
Vaccine
History
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Variolation
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18th century
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Edward Jenner
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Vaccination
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Vaccines
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Herd immunity
Types
of Vaccines
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Six basic types
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Attenuated whole-agent vaccines
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Inactivated whole-agent vaccines
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Toxoid
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Subunit vaccines
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Conjugated vaccines
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Nucleic acid vaccines
Types of Vaccines
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Attenuated whole-agent vaccines
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Live, but weak microbes
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Advantage
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Doesn’t usually require boosters
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Disadvantage
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Weak microbes
à
mutations
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Mutant reversal could cause danger
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Not for immunocompromised
individuals
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Ex. Measles, mumps, and rubella
(MMR)
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Inactivated whole-agent vaccines
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Dead microbes
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Advantage
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Safer
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Disadvantage
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Requires booster
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Ex. Rabies, polio, influenza
Types of Vaccines
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Toxoid
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Inactivated toxin
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Require boosters ever 10 years
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When was your last booster?
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Ex. Tetanus and Diptheria
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Subunit
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Antigenic fragments
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Recombinant vaccine
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Hepatitis B
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Safe
Types of Vaccines
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Conjugated vaccines
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Combined antigens with protein
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For children under two with poor
response to capsular polysaccharides
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Ex. Haemophilus influenzae
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Nucleic acid vaccines
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DNA vaccines
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Experimental development
New
Golden Age of Immunology
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Golden Age of Immunology 1870-1910
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New Golden Age
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75 new vaccines being developed
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AIDS, Malaria, and Cancer
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Improvements in old vaccines
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Adjuvants
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Improvements in delivery (pressure
gun, in food, patches, etc)
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Safer vaccines
Childhood Vaccine Schedule
Diagnostic Immunology
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Diagnostic techniques help us
determine the etiology of the disease
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Diagnostic techniques
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Microscopy
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Culture
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Test biochemical properties of
microbe
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Molecular
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Use PCR to amplify a gene
associated with the disease
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Identify the gene on a gel
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Immunological
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How big is an antibody? Can we
see it under a microscope?
Diagnostic Immunology
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Diagnostic immunology involves
using the principles of the immune system or antibody—antigen reaction to
diagnose diseases or detect antigens in bodily fluids
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5 important diagnostic tests
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Direct agglutination
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Indirect agglutination
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Hemagglutination
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Regular and viral
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Direct ELISA
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Indirect ELISA
Principles of Diagnostic Immunology
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Physician collects a sample
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Antigen sample
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A bodily fluid that contains the
infecting microbe or the microbes toxin
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Urine, feces, blood, skin, pus, throat swab, mucous, etc.
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Blood antiserum sample
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Blood antiserum contains the
antibodies that the patient made against an infection; if the patient is
infected with the suspected pathogen then his/her serum has those antibodies in
it.
Principles of Diagnostic Immunology
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If the sample is…
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Antigen then the physician exposes
it to pre-made antibodies for the suspected pathogen
§
Antibodies are produced by a
rabbit that was infected with that organism; they are collected in sterile vials
and sold by pharmaceutical companies
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Blood antiserum then physician
exposes it to an antigen from the suspected pathogen
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Antigen from microorganism is
prepared by pharmaceutical company
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It could be a toxin, an inactivated whole agent, or any subunit
from the suspected pathogen
TITER
§
The amount of antibody in the
antiserum
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Can be used to determine how far a
disease has progressed
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Direct agglutination tests can be
used to detect the antibody titer of a person.
§
When a person goes from no
antibody to elevated antibody then this is called seroconversion.
Agglutination Tests
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Agglutination occurs when antibody
binds to more than one antigen at a time.
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Direct
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Used to detect antibodies in
antiserum that are specific for large cellular antigens
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Used mostly to determine titer
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Determine stage of disease
Agglutination Tests
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Indirect agglutination
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For soluble antigens
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To detect antigens in patient
sample or antibodies in patient antiserum
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Soluble antigens or antibodies are
adsorbed onto latex beads
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Latex agglutination test
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Rapid
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10 min. Strep A throat test
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Throat swab sample exposed to beads coated with antibody specific
for Streptococcus A
HEMAGGLUTINATION
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Agglutination of RBCs
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Blood is the antigen in the
agglutination test
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Test used to determine blood type.
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If blood has type A antigens then
it will agglutinate in the presence of type A antibodies.
Viral Hemagglutination
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Some viruses agglutinate RBCs
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Mumps, measles, influenza
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Viral hemagglutination inhibition
test
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Antibodies bind to virus first
inhibiting clump RBCs when blood is added.
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Test:
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Take serum sample from patient and
mix with suspected viral pathogen
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Add blood
ELISA
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Enzyme Linked Immunosorbent Assay
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Enzyme reacts with substrate to
produce colored product
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Direct
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Enzyme is linked to an antibody
(made by pharmaceutical company)
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Detects antigen from patient
sample
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Ex. Home pregnancy test to test
for hCG hormone
§
hCG hormone is a protein present
in urine when a woman is pregnant
ELISA
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Indirect
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Enzyme is linked to anti-HISG (an
artificial antibody that reacts with ANY human antibody that is already bound to
an antigen)
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Detects antibody in patient’s
serum