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Flashcards in Exam 2- Short Answers Deck (7)
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1
Q

Give several reasons why antigen presentation by class 1 MHC molecules is important for the function of the adaptive immune system.

A
  • it allows the cells of the immune system to learn tolerance to self
  • normal body cells can present on MHC1 if there are issues within the cell that needs to signal for its death
2
Q

During their lifetimes, dendritic antigen presenting cells can be samplers, travelers, and presenters. Describe what DCs are doing during each of these three stages.

A

samplers- they take in extracellular fluid and spit it back out, they are in a resting state and do not present Ag
travelers- keeps in what it takes in for extracellular fluid , travels to the nearest lymph node
presenters- activate t cells by presenting antigens

3
Q

Mother nature uses “fail-safe technology” to prevent inappropriate activation of the immune system. Can you giver several examples?

A
  • MHC1 being present on all cells (except RBCs) to learn tolerance to self
  • T cell activation requires a two cell interaction so it is not ever ‘accidentally’ turned on
  • CTLs require activation by an APC
4
Q

How does a helper T cell know which cytokine profile to produce?

A

the cytokines floating around (either IL-12 for Th1 or IL-4 for Th2) influence the type of Th the cell becomes. These ILs are produced by the type of invasion in the body, if it is a bacterial/viral infection it will be Th1 if it is parasitic or pathogenic bacteria it will be Th2

5
Q

How does a helper T cell “call the plays” for B cells?

A

depending on the Th type the cytokines produced influence the B cell to class switch to the class that is the most effective for the type of infection the body is taking on

6
Q

What are the functions of the various secondary lymphoid organs?

A

lymph nodes serve as a place for T cells to become activated by DCs
peyer’s patch- allows the antigens collected by m cells to drain into the lymph to the lymph nodes
spleen- filters blood

7
Q

What is the advantage of having virgin T cells circulate through all the secondary lymphoid organs?

A

this allows them to crawl across many different DCs to see if they can find one that will activate them and begin the war in the body. since they go through all the different secondary lymphoid organs they are able to ‘scan’ different parts of the body that may be infected. if t cells were to only go to some organs and not others they may miss the DC cell presenting the antigen they need to become activated; it increases the odds of a faster, directed immune response