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27 Cards in this Set
- Front
- Back
Vaccine success stories
Protection of population groups from the symptoms of |
pertussis, diphtheria, tetanus, and rabies
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BCG vaccine for tuberculosis characteristics
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some protection against childhood TB but not for adult
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B. anthracis vaccine characteristics
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provides short lived immunity and must be re-administered yearly
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No Current Effective Vaccines
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Chlamydia trachomatis, Neisseria gonnorhoeae, Treponema pallidum, Vibrio cholerae, Hepatitis C, HIV, fungal pathogens, parasites,
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the injection of purified antibody or of serum containing antibody to provide rapid but temporary protection
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Passive immunization
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Passive immunization ex
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-newborn immunity based on acquisition of maternal antibody from the mother across the placenta or within breast milk
-antibody against Hepatitis B or rabies virus given shortly after exposure to virus to prevent infection -antibody against diptheria toxin to reduce toxicity |
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Passive immunization works to
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-Prevent disease after a known exposure
-Ameliorate symptoms of an ongoing disease -Protect immunodeficient individuals -Block the actions of toxins and the diseases they cause |
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what is the one thing that passive immunization cannot do?
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It CAN NOT provide long term protection
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Occurs when an immune response is stimulated because of challenge with an immunogen, either
An infectious agent (natural immunization) or Through exposure to microbes or their antigens in vaccines |
Active Immunization
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Active Immunization causes that Upon subsequent immunogenic challenge
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2ndary immune response is faster & more powerful
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Vaccines have been classically divided into 2 types
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live vaccines, and inactivated or subunit or killed vaccines.
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use a large amount of antigen to produce a protective antibody response without the risk of infection.
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Inactivated vaccines
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Inactivated vaccines are usually administered with
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an adjuvant to stimulate robust immunity (often stimulate TLR responses).
Example: Diptheria toxoid for protection against diptheria toxin. |
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stimulate innate immune responses (such as through TLR receptors) or promote antigen uptake by macrophages and dendritic cells.
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Adjuvants
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Major types of inactivated vaccines
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-Bacteria
Toxoid (inactivated toxin) Inactivated (killed) bacteria Capsule or protein subunits -Viruses Inactivated virus Protein subunit |
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To stimulate a robust immune response against a poor antigen, the antigen may be linked or conjugated to a protein that stimulates host immune responses
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Conjugate vaccines
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Conjugate vaccines may be developed to target
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important component that is not a good immunogen, such as a bacterial polysaccharide capsule.
Example: conjugation of pneumococcal capsule to inactivated diptheria toxin. |
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Advantages for inactivated vaccines
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Useful for protection against pathogens that can’t be attenuated
Generally safe Can be stable |
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Disadvantages of inactivated vaccines
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-Immunity is usually not life-long
-Immunity may only be humoral and not cell-mediated -The vaccine does not elicit a local IgA response -Booster shots are required -Larger doses must be used. |
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Prepared with organisms that are limited or attenuated in their ability to cause disease
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Live vaccines
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Live vaccines are useful for
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stimulating protective T cell mediated responses (such as CD8 T cells) against intracellular pathogens.
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problems with live vaccines
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: (1) the attenuated organism may still be dangerous for immunosuppressed people or pregnant women;
(2) the vaccine may revert to a virulent form (3) the viability of the vaccine must be maintained |
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Examples of inactivated vaccines:
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Polio (Salk vaccine), influenza, Hepatitis B, Rabies, Diptheria, Pertussis subunit vaccine
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Examples of live vaccines
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Polio (Sabin vaccine), Measles, Mumps, Rubella, Varicella-zoster, Smallpox (attenuated vaccinia virus)
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consist mainly of synthetic peptides, carbohydrates, or other antigens.
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Synthetic vaccines. Generally considered safer than (for example) products purified from bacteria.
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Obstacles to vaccination
Pathogen based: |
target proteins resemble host proteins
antigen is hidden until function is required antigen varies at a high frequency virulence factors inactivate host immunity. |
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Obstacles to vaccination
Human based: |
vaccines are very expensive to develop and test
vaccines may not be money makers for industry may be lack of good animal models failure to comply with booster schedule stigma associated with vaccine (STI infections) vaccines themselves are expensive vaccine may not be stable in areas lacking refrigeration. |