L16 B cells

Question 1

what are the precursors of B cells (2)

Answer 1

bone marrow stem cells

lymphoid precursors

Question 2

where does maturation of B cells occur and how is it different to T cells

Answer 2

occurs in the bone marrow where T cells mature in the thymus

Question 3

what can B cell turn into once activated

Answer 3

plasma cells

memory cells

Question 4

what a memory cells

Answer 4

cell that hang around for a long period of time that can differentiate into plasma cells to secrete antibodies

Question 5

what are plasma cells

Answer 5

antibody secreting cells

majority are short lived

Question 6

where do some of the plasma cells end up if they arent short lived

Answer 6

bone marrow

thymus

Question 7

example bacteria/toxin that if immunised the plasma cells will continue to produce antibodies in the bone marrow and thymus years later

Answer 7

tetanus toxin

Question 8

how does communication between T cells and B cells occur

Answer 8

binding of MHC II to TCR

Question 9

what can early B cells that haven’t turned into memory or plasma cells do

Answer 9

bind native (unprocessed) antigen to antibodies that are bound to the plasma membrane

Question 10

what happens to B cells during an immune response

Answer 10

class switching

Question 11

what is class switching

Answer 11

the constant region of the heavy chain of the antibody is changed (switched)

Question 12

what does class switching do?

Answer 12

changed function of the antibody

Question 13

What does IgA do

Answer 13

protect the mucoss

Question 14

What is IgG

Answer 14

good all round antibody that can cross the placenta

Question 15

what are antibodies composed of

Answer 15

two heavy chains and two light chains

Question 16

how are the light and heavy chains of the antibodies attached

Answer 16

disulphide bonds

Question 17

how are the two heavy chains attached

Answer 17

disulphide bonds

Question 18

what is the last component of an antibody

Answer 18

glycoprotein (carbohydrate)

Question 19

what does the carbohydrate on antibodies do ?

Answer 19

impart different functions

antigen recognition

Question 20

two ways antibody can be expressed

Answer 20

membrane bound or secreted

Question 21

what determines if an antibody will be secreted or membrane bound

Answer 21

mRNA splicing
transmembrane domain that is present in naïve B cells undergoes splicing when it becomes a plasma cell so it will be secreted

Question 22

what types of B cell receptors complex (antibody + receptor complex) do naïve B cell express on their surface

Answer 22

IgM and IgD

Question 23

what molecules do IgM and IgD associate with

Answer 23

Ig-alpha

Ig-Beta

Question 23

what molecules do IgM and IgD associate with

Answer 23

Ig-alpha

Ig-Beta

Question 24

What are Ig-alpha and beta

Answer 24

signalling molecules | transmembrane proteins

Question 25

what do the signalling molecules do?

Answer 25

signals the B cell to activate

Question 26

where does isotype switching of the B cells occur during an immune response

Answer 26

thymus

Question 27

what happens during the generation of diversity

Answer 27

B cells are rearranging their BCR

Question 28

are any B cells the same

Answer 28

no

Question 29

components of the light chain of a B cells

Answer 29

V J C

Question 30

what happens to the V and J regions during DNA rearrangement

Answer 30

1 V and 1 J gene are spliced together

Question 31

what happens to any genes between the V and J genes that are being combined

Answer 31

from a circle and float away to be degraded

Question 32

how many genes are in the V regions

Answer 32

50

Question 33

How many genes are in the J region

Answer 33

5

Question 34

How many genes are in the D region

Answer 34

25

Question 35

what is the C region/ what does it do

Answer 35

constant region complement activation binding to phagocytes through FC receptor

Question 36

can the C region change?

Answer 36

yes, class switching can occur but not during gene rearrangement

Question 37

how are B cells activated

Answer 37

recognise native antigen | receive help from CD4 T cell

Question 38

what happens to the native antigen when it binds to a B cell antibody

Answer 38

digested into peptides in an endosome and presented on MHC II to T cell

Question 39

what is the key difference between plasma cells and B cells

Answer 39

extensive ER and golgi for producing large amounts of antibodies

Question 40

what happens to a memory cells that comes into contact with antigen

Answer 40

becomes a plasma cell | does not require a T cell

Question 41

what is the type of antibody isotypes that is the first burst during a primary immune response

Answer 41

IgM

Question 42

during a secondary or further immune response what are the memory cells inclined to do

Answer 42

class switch to IgG

Question 43

where and how often does class switching occur

Answer 43

heavy chain | constantly

Question 44

what is IgE function

Answer 44

parasites and allergic respeonses

Question 45

what is IgA function

Answer 45

mucosal protection

Question 46

how does class switching occur

Answer 46

the M and D regions of the coding chain are 'looped out'

Question 47

what happens to a B cell that is autoreactive to self antigen

Answer 47

programmed to die | apoptosis