What term describes a laboratory modification of a pathogen?
A vaccine.
What validates the usefulness of vaccines.
The characteristics of memory cells.
You must be exposed to various epitopes in order to have permanent immunity against those immunogens. Vaccines provide re-exposure.
What is the most desirable modified form of a pathogen to use in a vaccine?
A live (attenuated) pathogen that has been geneticallyaltered to make it non-virulent/non-pathogenic.
True or False?
The antibodies or CTL's the body produces in response to a live vaccine are a waste of energy.
True.
The immunogen is non-pathogenic. However, the desired result is also the production of memory cells.
What is the 2nd most desirable modified form of a pathogen to use in a vaccine?
A dead, in tact pathogen.
Why is a "dead" vaccine less desirable than a "live" one?
The body's immune system gives priority to live pathogens since they can proliferate.
Why must some vaccines be injected in a "dead" form?
Some microbes have the genetic ability to mutate back into their virulent state.
True or False?
A dead vaccine leads to shorter-lived memory cells.
True.
Why don't our macrophages and neutrophils completely phagocytize the microbes in a "dead" vaccine and thus prevent an immune response?
Ingredients in the vaccine signal the body not to completely phagocytize the microbes and to save IDP's. (A possible use for egg albumin).
What is the least desirable modified form of a pathogen to use in a vaccine?
Particulate matter from a ground up or enzymatically treated pathogen.
Why might a "particulate" vaccine be the only option in some cases?
Some pathogens lose their surface epitopes upon modification or death. Therefore, they must be ground up or enzymatically digested while the epitopes still exist. Sometimes this treatment can make them more expressible.
Explain the new technology that may create a 100% harmless method of producing memory cells.
1.) Extract a gene from a pathogen's genome that codes for an epitope
2.) Place in a viral vehicle
3.) Body's phagocytic cells engulf and encorporate gene
4.) Macrophages produce epitope naturally and present to T-helper cells
If a person complains that a vaccine actually caused them to contract the illness, what likely happened?
They came into contact with the real immunogen shortly before receiving the vaccine.
What term describes the suspension molecule that a vaccine's pathogen is attached to?
A vehicle.
When it is said that someone is allergic to a vaccine, what is real cause to the allergy?
The individual is allergic to the vaccine's vehicle. For example, egg albumin.
Why is a vehicle necessary for vaccine injection?
A vaccine injected without a vehicle will dilute in the blood stream almost immediately. Vehicles keep the pathogen/epitope confined locally to the site of injection, making it easy for the immune cells to find.
What attracts immune cells to the site of a vaccine injection?
1.) The inflammatory response from the needle-prick
2.) The vaccine's vehicle can sometimes serve as an additional immunogen (egg albumin).
If an individual is allergic to a vaccine's vehicle, what alternative do they have?
If no other vehicle exist for that vaccine, it is better not to recieve it at all - a real immune response from the real immunogen is preferable.
What is the first criterion that a cell or molecule must meet in order to be considered an immunogen?
It must have a certain minimum size of 1000 daltons. Anything smaller will filter out of the glomerular capillaries and be eliminated. This refers only to molecules.
What is the second criterion that a cell or molecule must meet in order to be considered an immunogen?
It must have a certain degree of structural complexity. This only refers to molecules. Therefore, proteins are the most immunogenic type of molecule.
What is the third criterion that a cell or molecule must meet in order to be considered an immunogen?
It must be degradable/phagocytizable, otherise an IDP cannot be made.
What is the fourth criterion that a cell or molecule must meet in order to be considered an immunogen?
It must be of different genetic origin (foreign).
Note: if an organism has not penetrated skin or crossed a mucous membrane, it has not entered your body.
What term describes a molecule so small/simple in structure that it can not induce an immune response in a competant individual?
A hapten.
How can a hapten be modified in order to cause an immune response?
It could be bound to a larger molecule/cell.
What is the basis for attempting to make the active molecule in drugs as small in size and structure as possible?
If it is small enough, the body will not recognize it and can not initiate an immune response and thus make the drug ineffective.
What is the cause of a drug allergy?
The drug has the ability to bind to a particular molecule or cell surface. Upon binding, the complex is large enough for the immune system to recognize, and antibodies are produced in response.
True or False?
A typical antibody can bind three of the same type of immunogen.
False.
It can bind two of the same type of immunogen.
What are the adverse effects of an allergic reaction to PCN?
Antibodies bind RBC/PCN complexes and cause clumping. Capillaries and arterioles become blocked.
What symptoms might be expected due to a PCN allergy.
1.) Back pain - kidney capillaries (usually first symptom)
2.) Heart pain - coronary arteries
3.) Shortness of breath - alveolar capillaries
4.) Confusion - BBB
5.) Rash - dermal capillaries
True or False?
Less antibodies are produced (or required) for a secondary immune response.
