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Flashcards in Chapter 20 Deck (19)
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1
Q

describe adaptive and innate immunity. name the key cell players in each system

A

adaptive: ag specific host defense (t and b cells, APCs)
innate: early host defense (nph, eo, baso, mast, nk)

2
Q

self tolerance is a combo of 2 types of tolerance known as ___ and __. These are learned where in development?

A

Central (during lymphocyte development in the thymus) and peripheral

3
Q

b cell receptors recognize antigen directly. T helper cells recognize peptides presented on MHC __ and cytotoxic T cells recognize peptides presented on MHC __.
Which MHC complex is specific to antigen presenting cells? ___
Which is present on all cells in the body? __
What types of peptides are expressed or presented on MHC I? ___
What types are on MHC II? ___

A
II
I
II
I
I - shows endogenous peptides
II - shows exogenous
4
Q

define humoral immunity. what are the key players

A

Part of the adaptive immune response that has to do w aby mediated response.
B cells are key players.
T helpers nb to stimulate this response

5
Q

define cell mediated immunity - what are the key players

A

Immunity initiated by activation of T lymphs Cytotoxic t lymphs are effectors
T helpers are nb to stimulate the response

6
Q

What is the intracellular structure responsible for degrading endogenous proteins into small peptides for presentation to the MHC complex?
How are exogenous proteins degraded into peptides for presentation on MHC?

A

Proteosome

Endosomes w/in APCs

7
Q
Cytotoxic T lymphs are primarily used to destroy cells infected by \_\_\_ and what other type of cells? \_\_\_
CTLs are CD4 or 8 positive? \_\_\_
And recognized peptides expressed on which class of MHC? \_\_\_
How do they kill their target cells? \_\_\_
A
viruses
tumor cells
8
I
perforin and granzymes
8
Q

T helper cells are CD4 or 8+? __

They recognize peptides presented on what MHC complex? __

A

4

II

9
Q

T helper cells are divided into TH1, TH2 and TH3 types.
TH1 cells secrete____
These cells are involved in what branch of the immune system? _____
List at least 3 cytokines secreted by TH2 cells. ___
They are involved in the activation of what cells and are nb in what branch of the immune system? ___
What is the main function on TH3 cells? ___

A
IL-2, IFNy, GMCSF
CMI
IL-4, IL5, IL10, IL13, GMCSF
Activate B cells in humoral immunity
Secrete TGF beta or IL-10 to regulate the immune system. Nb in maintaining peripheral tolerance
10
Q

The large amt of variability in TCR has to do w/ gene rearrangement of the variable, diversity and joining segments of the gene. There are also 3 hypervariable regions referred to as the ___ which are nb for antigen recognition as they contact the peptide antigen. What part of the TCR complex is responsible for intracellular signalling?

A

complementary determining regions

CD3 intracellular signaling

11
Q

CD28 is expressed by what cells? function?

A

on T cells, costim molecule for immune activation

12
Q

IL-2 promotes growth of what cells?

A

All t cells including TH and CTLs

13
Q

What interleukin is required by B cells for Aby production

A

IL-12

14
Q

describe t cell development including where it occurs and the procceses of tolerance and selection

A

In the thymus.
If TCR interacts weakly w/ self MHC then there is positive selection, IF TCR interacts very strongly w/ MHC then there is negative selection (part of tolerance).
Self reactive thymocytes escape thymic detection dt proteins in the body existing o/s of the thymus and t/f not being present at the time of selection. (central tolerance = thymus). peripheral tolerance is needed for the problem of AG not present in the thymus. So, peripheral tolerance is the induction and maintenance of unresponsiveness in mature T cells to self AGs bc of TH3 cells.

15
Q

what is anergy

A

unresponsiveness of t cells to their antigen (another way of having tolerance)

16
Q

t cells interacting w apcs expressing agn will have a different response depending on the presence or absence of co-stim mols. what is one such co-stim molecule?

what would be the response of the t cells if there was a lack of co-stim mols or presence of co-stim mols?

A

CD28

w/o costim - tolerance by clonal deletion or anergy
w/ costim - efficient immune response

17
Q

how do nk cells recognize target cells and how do they kill

A

detect changes in expression level of MHC mols on the surface of target cells
if MHC I is low the cells are killed. Perforin like for CTLs.

18
Q

CD28 on T cells interacts w/ either B7 or CTLA4. Which one positively stimulates an IR and which one inhibits it?

A

B7 positive

CTLA4 negative

19
Q

Name 2+ ways tumors avoid an IR

A

Downregulate MHC1
Secrete immunosuppressive cytokines such as TGFb and IL-10
Tumors upregulate FAS ligand which binds FAS on CTLs leading to apoptosis