Antigen Receptor and Lymphocyte Development Flashcards Preview

CMBM E4 CB > Antigen Receptor and Lymphocyte Development > Flashcards

Flashcards in Antigen Receptor and Lymphocyte Development Deck (32):
1

What is an antigen?

Antigen (Ag) is a molecule which specifically binds a T-cell receptor or an antibody (Ab) site

2

What is an immunogen?

Any molecule that elicits an immune response by binding to a T-cell receptor or an antibody

3

What are the specific immune receptors of the adaptive immune response?

T-cell receptors (TCR)
B-cell receptors (BCR)

These receptors are formed/generated to aid in immune response.

4

What are the preformed antigen receptors?

PRR
TLR
CR
Fc

These act in the innate system. They are general, preformed antigens. NOT SPECIFIC.

5

What antibodies are displayed on mature B-cells?

IgM
IgD

6

When is the constant region spliced during Ig development?

During RNA processing

7

What creates diversity in the development of Igs?

TdT--transferase protein, adds nucleotides to the end before ligase proteins seal segments together.

8

TdT is present in which cells only?

B-cells

9

Where do B cells mature?

Follicular region of lymph node

10

Where does a B cell become activated?

In the paracortex of a lymph node

11

Which region is combined first in Ig recombination?

D-J

12

RSSs contain how many base pairs?

12 or 23

13

What is an RSS?

Recombination Segment Sequence

Part of the V, D, J regions on genes for Igs

14

How many RSSs do V, D, and J have?

V: 1
D: 2 (joins with both V and J)
J: 1

15

What opens the hairpin loop to allow nucleotide addition to the immunoglobulin?

Artemis (protein enzyme)

16

Where do naive T-cells enter the thymus?

Corticomedullary area

17

What guides T cells to the thymus?

CCR9 (receptor on thymocyte) + CCL25

18

Which chemokine is essential in bringing T cell precursors into the corticomedullary thymus?

CCR9

19

What does CCR9 bind to?

CCL25

20

Where is CCL25 produced?

The cortex of the thymus

21

Which chemokines guide the T cell from the cortex to the medulla during maturation?

CCR7 receptor (on thymocyte) + CCL21 and CCL19

22

Where do positive and negative selection of T cells occur?

Positive: Cortex
Negative: Medulla

23

When do T cells begin displaying CD3?

When they become DN3

24

When do T cells display CD25?

DN2
DN3

25

What does CD25 bind to?

IL-2

26

When is a thymocyte committed to becoming a T cell?

After DN3 --> it is now displaying a TCR

27

What must happen for a T cell to finish positive selection and enter negative selection?

TCR must interact with self MHC. If it does not, apoptosis will occur.

28

Where do T cells become single positive cells?

Medulla

29

What promotes the elimination of auto-reactive T cells in the medulla?

AIRE (auto-immune regulator protein-->transcription factor)

30

What drives negative selection of single positive T cells in the medulla?

AIRE

31

What is CD44?

Adhesion molecule on thymocytes

32

Which chain is developed first in T cell maturation?

Beta chain