Tolerance and MHC restriction Flashcards Preview

Immunology Exam #2 > Tolerance and MHC restriction > Flashcards

Flashcards in Tolerance and MHC restriction Deck (35)
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1

Does the Thymus have Afferent lymph

NNNOOOOO

2

does the Thymus have HEVs

NNOOOOO

3

how does the T cells enter the Thymus

blood stream

4

do the T cells that enter the thymus express anything

no CD4, no CD8, no TCR, very little Fas protein,

5

Where are T cells created

Bone marrow

6

what does a very naive T cell express

lots of Bcl-2

7

what is Bcl-2

protein that protects against apoptosis

8

what do T cells mature into

Double Positive cells (in the thymus)

9

what makes DP cells Double Positive

they contain both CD4 and CD8 molecules

10

what do DP cells express

- lots of Fas protein
-very little Bcl-2
(become very vulnerable)

11

What 2 tests do DP cells have to pass to live

1. MHC restriction
2. Tolerance to Self

12

What is the other name for MHC restriction test

Positive Selection

13

where does the MHC restriction test take place

the cortex of the thymus

14

what does the cortical epithelial cells ask the T cells in the MHC restriction test

Do you have receptors that recognize one of the MHC molecules on my surface?

15

what is the correct answer to the MHC restriction test

T cell are supposed to recognize one of the MHC molecules on the cortical epithelial cells

16

What does the cortical epithelial cells of the thymus express

1. endogenous peptides on MHC 1
2. exogenous peptides on MHC II
3. Endogenous peptides on MHC II (cross present)

17

T/F all mature T cells must recognize antigen presented by MHC molecules

true

18

After the MHC restriction test what does the Dp cell turn int

a Signle Positive Cell (SP)

19

what destriguishes a T cell as a SP cell

the T cell has now chosen CD4 or CD8

20

What is the other name for the Tolerance Test

Negative Selection

21

where does the tolerance test take place

In the Thymus in the Medulla

22

What is the job of the Thymic Dendritic Cell in the tolerance test

Display self peptides on MHC molecules (correct answer NO)

23

What is the job of the medullary thymic epithelial cells in the Tolerance Test

-cross present endogenous protein on MHC II
-express thousands of tissue-specific proteins

24

How long does the testing last

2 weeks

25

how many pass the test

2 million (3% out of 60 mil)

26

Since we cant present every protein to T cells how do we combat that

1. Make sure T cells never come in contact with proteins that werent on the test
2. N T reg cells

27

T/F secondary lymphoid tissue tend to express the same antigen set as found in the thymus

True

28

What does N T reg stand for

Natural regulatory T cells

29

What is the job of the N T reg cells

Enter secondary lymphoid tissue and inhibit self reactive T cells

30

T cells are anergized if....

they recognize an antigen but do not get co-stimulated
(where B7 and MHC expression in low in the tissue)