T-helper0 cells (naive cells) have a life span of __________.
20 to 25 years, they are "long lived."
True or False?
TH0 cells have an extremely low metabollic rate.
True.
In order to live 20 - 25 years, they must have a low metabollic rate - just enough to keep them viable.
When a TH0 meets an APC and transforms to a TH2, what happens to its metabollic rate?
The T-helper cell's metabollic rate reaches near maximum.
True or False?
Only the single TH2 cell from the TH0 - APC interaction is needed to find an appropriate B-cell due to the rapid circulation of the body's vascular system.
False.
The TH2 undergoes rapid proliferation (mitosis).
What determines how many TH2 cells must be produced in order to find an appropriate B-cell during a humoral response? How many might that be?
1.) The immune monitoring system
2.) 100,000 - 500,000
Why are so many TH2 cells produced after the APC determines a humoral response is needed?
In order for an appropriate B-cell to be found in the shortest amount of time.
What is an appropriate B-cell?
An appropriate B-cell has the genes to code for the structure of the antibody needed to bind to the presented target epitope. It will have in tact receptors on its surface for the epitope.
How many appropriate B-cells exist in the body for any given epitope?
6 - 20.
True or False?
A TH2 cell will find an appropriate B-cell in a very short amount of time.
True.
What is the typical life span of a circulating B-cell?
3-7 days, with a metabollic rate of almost zero.
True or False?
When a progeny TH2 cell makes direct contact with an appropriate B-cell, the B-cell is activated but does not need to undergo mass mitosis.
False.
100,000 - 200,000 progeny B-cells will be produced.
Progeny B-cells will convert into one of the following two sub-types of cells:
1.) Plasma cells
2.) Memory cells
True or False?
Most of the progeny B-cells will convert to memory cells.
False.
Most will convert to plasma cells.
What is the function of plasma cells?
Plasma cells produce the antibodies for the immediate crisis (infection) of a humoral response.
True or False?
A plasma cell may continue to dump antibodies into the blood stream or other body fluids for a number of days.
False.
A given plasma cell produces billions of antibodies until its cytoplasm is full. The cell then dumps the product and dies.
True or False?
Antibodies bind to immunogens and are responsible for carrying out the destruction process.
False.
They only assist in the destruction of the immunogen - they themselves do not kill anything.
True or False?
In a cell mediated response, a CTL binds to and assists in the destruction of an infected or transformed cell - they themselves do not kill anything, however.
False.
A CTL carries out the entire destruction process itself using highly toxic chemicals.
A _________ response describes the first time the body reacts to a given immunogen, and usually takes _________ days for antibody production to start.
1.) Primary
2.) 4-10
Why does a antibody production take so long in a primary response? (List the necessary steps leading up to this event).
1.) IMS signals APC's to save IDP upon contact
2.) APC finds and saves IDP
3.) APC presents to appropriate TH04.) Proliferation of TH1 or TH2 cells
5.) Progeny T-cell finds appropriate B-cell
6.) B-cells differentiate
True or False?
Nothing can be done to speed up the proliferation of T-helper cells.
False.
Although mitosis cannot be sped up, they do spend less time in interphase than a typical cell.
What is a benefit of a fever?
Increased body temperature slows the growth of many types of bacteria, giving the immune system time to catch up.
Memory cells are derived from ______ and ______.
1.) Activated B-cells
2.) CTL's
True or False?
A memory cell remembers multiple epitopes from different immunogens that were present at the time of its production.
False.
Memory cells are epitope secific for the single epitope (of the single immunogen) for which they were created.
Memory cells can have a life span of up to ________ years.
20 - 25.
What occurs of a memory cell encounters its complementary epitope/immunogen?
The cell proliferates into plasma cells or CTL's (depending on type of response) and more memory cells.
What is the lifespan of a memory cell dependent on?
1.) The cell itself
2.) Type of invader it was made to recognize
True or False?
Memory cells provide lifelong immunity with or without re-exposure to the immunogen.
False.
Due to the lifespan of memory cells, an individual must be periodically re-exposed to the epitope/immunogen --> basis for vaccines.
What percentage of the population must be vaccinated in order to prevent an epidemic?
75 - 85%.
In order to have an epidemic, an immunogen needs enough unvaccinated hosts in close proximity for rapid transmission.
A _________ response describes the second time (or more) the body reacts to a given immunogen, and usually takes _________ for antibody production to start.
1.) Memory cell / secondary
2.) 18 - 36 hours (about a day)
Are the symptoms of an infection felt with a primary response? With a secondary response?
1.) Yes - for the time it takes to produce antibodies (4-10 days)
