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Flashcards in Lymphocyte Function Deck (38)
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1

what are all lymphocytes?

antigen specific

2

how is speciality achieved?

antigen receptor on cell surface

3

what are the B cell receptors?

cell surface antibody

4

what are the T cell receptors?

T cell receptor (TCR)

5

what are cells of the same specificity?

clone

6

what synthesises and secretes immunoglobulins?

B cells

7

what do B lymphocytes need to be secreted?

they need to be activated and differentiate into plasma cells

8

what is the antigen receptor on B cell?

the antibody that the B cell is programmed to make

9

what happens if an antigen receptor on a B cell binds to a specific antigen?

stimulus for B cells to divide and produce clonal expansion and differentiate

10

What are antibodies encoded by?

multiple gene segments

11

what are VH domains coded by?

3 gene segments:
-variable
-diversity
-joining

12

what are VL domains coded by?

2 gene segments:
-variable
-joining

13

what other domain is there apart from VH and VL domains?

constant domains

14

what happens to make variations of the heavy chain?

- V, D and J segements
-DNA spliced out during early development of B cell to 0
-produce functional V-D-J gene
- transcription
-splicing out
-translation

15

what happens to make variations of the Kappa light chain?

-Vk and Jk segments
- DNA spliced out during early development of B cell
- transcription
-splicing out
-translation

16

what do all B cells begin by making?

IgM

17

Describe class switching.

memory cells produce IgG, IgA or IgE with same specificity

18

what do T cell independent antigens produce?

IgM antibodies in small amounts

19

what do the vast majority of antibody responses require?

T cells to help

20

what are all T cells specific for?

one antigenic determinant

21

Describe T cell receptors.

1. Structure on T cell surface that recognises antigen
2. Structurally related to immunoglobulin
3. Similar complex gene structure- V,D,J,C gene segments encoding V and C regions
4. Binds to antigenic peptide associated with MHC

22

what is TCR very similar to?

Fab fragment of an antibody

23

Describe the structure of TCR.

-α and β chains are
linked by disulphide bond
- Majority of T cells have
αβ TCR
-Minority of T cells have
alternative, structurally
similar TCR made up of
different polypeptides
designated γ and δ
-termed γδ T cells

24

Why do Vα and Vβ (TCR) have hypervariable loops or CDRs?

responsible
for detecting antigenic peptide in combination with MHC

25

what are the 2 major T cell classes?

-helper T cells
-cytotoxic T cells

26

what is the TCR on helper T cells associated with?

CD4 and CD3

27

what is the TCR on cytotoxic T cells associated with?

CD8 and CD3

28

what are CD4 and CD8 required for?

to make an effective response to antigen

29

what do CD4 and CD8 mediate?

additional contacts with MHC molecules

30

what connects the MHC Class II on the antigen presenting cell to the TCR on the helper T cell?

antigenic peptide