MMG Immunization and Testing
Terms
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- What are two ways to make artificial immunity?
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-active
-passive - What is active immunity?
- -administration of a vaccine so that the patient actively mounts a protective immune response
- What is passive immunity?
- -individual acquires immunity through the transfer of antibodies formed by an immune individual or animal
- What are three types of vaccines?
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-attenuated (live)
-killed (inactivated)
-toxoid - Describe attenuated vaccines.
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-modified live vaccines
-uses live pathogens that have reduced virulence so they don't cause disease - Describe killed, or inactivated, vaccines.
- -either whole agen vaccines produced with deactivated, but whole microbes, OR subunit vaccines produced with antigenic fragments of microbes
- What is a toxoid vaccine?
- -chemically or thermally modified toxins used to stimulate active immunity
-
What are two types of aquired immunity?
How are these split? -
-naturally
-artificially
*can be split into active or passive - What is naturally acquired immunity?
- -immune response against antigens encounterd in daily life
- What is artificially acquired immunity?
- -response to antigens introduced via a vaccine
- What is active acquired immunity?
-
-active response to antigens via humoral or cell-mediated response
*natural= infections
artificial= antigen in vaccine - What is passive acquired immunity?
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-passively receive antibodies from another individual
*natural= placenta or milk
artificial= antisera and antitoxins (preformed antibodies) - What is herd immunity?
- -when an individual is vaccinated and infects those around them
- In attenuated viral viaccines, what happens?
- -vaccine triggers a cell-mediated immune response dominated by TH1 and cytotoxix T cells
- What can attenuated vaccines contain and result in?
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-contain replicating microbes to stimulate stong immune response (from large number of antigens present)
-can result in mild infections but no disease - What are some problems with attenuated vaccines?
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-may retain enough virulence to cause disease in immunosuppressed individuals
-pregnancy; crossing placenta
-modified viruses may revert to wild type or mutate to a virulent form - Overall, what are some problems with vaccinating?
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-mild toxicity
-anaphylactic shock
-residual virulence
-certain vaccines cause/trigger autism, diabetes, and asthma (unsubstantiated!!) - What is the down-side to toxoid vaccines?
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-require multiple doses to stimulate antibody-mediated immunity
*still useful for some bacterial diseases though -
What is the current target for new vaccine technology?
Currently, what can be done? -
-make vaccine that are more effective, cheaper, and safer!
-a variety of recombinant DNA techniques can be used to make improved vaccines - Why are inactive vaccines safer than attenuated?
- -can not replicate or mutate to virulent form
-
How are inactivated vaccines inactivated?
What is most important to preventing while doing this? -
-formaldehyde (cross-links proteins and nucleic acids)
-must not alter antigens responsible for stimulating protective immunity - How do inactivated vaccines work in the body?
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-recognized as exogenous antigens and stimulate TH2 response
-this promotes antibody-mediated immunity - What are 4 problems with inactivated vaccines?
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-no herd immunity
-inflammatory response from nonantigenic portions of microbe
-antigenically weak
-high or multiple doses, or use of adjuvants may cuase allergic reactions (though more effective) - What is an adjuvant?
- -substance that increases the antigenicity of the vaccine
- What does being antigenically weak mean?
- -microbes don't reproduce and provide many antigenic molecules to stimulate the immune response
- What is used in immune testing?
- -antigen-antibody interactions in blood and serum diagnostically
- How is the proper immune test chosen?
-
-based on suspected diagnosis
-cost to perform test
-speed of result - What are the two ways to test antigen-antibody interactions during immune testing?
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-use known antibodies to detect antigens associated with infection
-use antigens to detect antibodies in patients blood to determine exposure to specific pathogen - What is antiserum?
- -serum from human or animal donors that have been infected with the disease or immunized against it
- What are the limitations of passive immunity?
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-contain antibodies for multiple antigens
-repeated injections can trigger allergic reactions
-antisera may be contaminated with virus
-antibodies of antisera are degraded relatively quickly - What is the most beneficial aspect of passive immunity vaccination?
- -quick protection against recent infection