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15 Cards in this Set

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in general what do the three classes of effector T cells do?
TH1 stimulate macs to kill intracellular pathogens in the mac and are good at activating cytotoxic T cells. Th2 cells are more in the lymph nodes for activation of B cells and the antibody response. CD8 cells go to the site of infection to kill virus infected cells
what cells direct the adaptive immune response?
CD4 T cells
explain the process of how TH1 cells can activate macs at the site of infection.
the mature dendritice cell with ingested bacs goes to the peripheral node and then encounters a naive T cell and stimulates it to become active by joining MHC II with antigen and the TCR as well as CD28 on the T cell with B7 on the denritic cell. The dendritic cell also releases IL12 to tell the T cell to become a TH1. The T cell now differentiates into a Th1 cell and migrates to the site of infection where it encounters macs that have ingested bacteria and are presenting antigen bound MHC II that this Th1 cell is specefic for. They then bind MHC and TCR as well as CD40 and the Th1 cell release IFN gamma to tell the mac to destroy those intracellular bacs
What specefic chemicals and proteins are upregulated when a mac is activated by a Th1 cell?
increase class II MHC, increase TNF factors, oxygen radicals , and nitric oxide
when and how does a granuloma form?
when pathogens cannot be completely eliminated from a mac, Th1 cells and uninfected macs "wall off" and surround the infected macs and keep secreting chemicals to try and kill the bacs
what activates CD8 cells?
CD4 T cells (mainly Th1) via IL 2 and co stimulation
how do activated CTL cells find the cells they want to kill?
they have non specefic adhesion molecules that allow them to jump from cell to cell until they find the desired MHC I and antigen then they form a tight bond and kill that specefic cell
what are the stages in killing a cell via CTL?
CTL finds its target, forms tight conjugate bond, rearranges its cytoplasmic granules to the site of this bond, release the contents into the cell at the conjugate bond so it does not hit the other cells, then the target cell dies by apoptosis
what are the main ingredient in the granules of the CTL's?
perforin and granzymes
what biochemical pathways does the CTL use to facilitate apoptosis?
use of caspases or more rarely a FAS/FASL bond to initiate the caspace cascade
what T cells can make cytokines?
all of them
what cells are activated by interferons and are active at early viral infections?
NK cells
how are NK cells activated?
by activation receptors on a cell. Note they are non specefic killers and are inhibited by MHC (allows for less host cell death and allows for death of infected cells that have lost their MHC expression abilities due to their infection)
what are the three phases of the T cell response?
activation and expansion, death, and memory (~5% of T cells do not die and remain for memory)
compare primary T cell response with secondary T cell response.
higher frequency of antigen specefic cells, faster, develop effectors more efficiently