B Cell Essay

Question 1

What are B cells?

Answer 1

One of the two main immune lymphocytes which mediate adaptive immune response

Question 2

What are B cells responsible for ?

Answer 2

Production of antibodies

Question 3

What are antibodies ?

Answer 3

Proteins found in the blood in response to specific antigens

Question 4

What are the 5 groups of antibodies ?

Answer 4

M,A,D,G,E

Question 5

What is the most abundant antibody?

Answer 5

IgG

Question 6

What % of serum immunoglobulins does it make up?

Answer 6

75%

Question 7

In antibodies what creates the differences between then?

Answer 7

Variable regions

Question 8

Where does B cell development take place ?

Answer 8

Bone marrow

Question 9

Where do lymphoid progenitor cells receive signals from?

Answer 9

stromal cells

Question 10

What are stromal cells composed of ?

Answer 10

Mesenchymal stem cells

Question 11

What do Mesenchymal stem cells do?

Answer 11

Begin B cell development

Question 12

What do MsC provide B cells with ?

Answer 12

Adhesions to allow them to attach. To growth factors such as IL-7

Question 13

What do these growth factors allow ?

Answer 13

For B cells to proliferate and stay in the bone marrow and for an early pro- B cell to be generated

Question 14

Why is the heavy chain rearranged first?

Answer 14

If successful will prevent any further heavy chain rearrangements taking place in a process called allergic exclusions

Question 15

What happens in heavy chain gene rearrangement

Answer 15

One of the D segments joint with a J gene segment

Question 16

What happens after successful H chain rearrangement ?

Answer 16

Cell induces for the L chain to rearrange

Question 17

Why is L chain rearrangement crucial?

Answer 17

Results in a protein that will pair with H chain, if unsuccessful the B cell will die

Question 18

What is the B cell considered after successful binding of D&J segments?

Answer 18

Late pro B cell

Question 19

What does a late pro-B cell require ?

Answer 19

VDJ recombinase

Question 20

What does VDJ recombinase do?

Answer 20

Attached the D-J segment to a V segment Indicating heavg chain antigen binding sites complete

Question 21

What happens in positive selection?

Answer 21

The late pro-B cells that have successfully rearranged their IG genes and express a BCR signal receive a signal and those who do no undergo apoptosis

Question 22

What is the purpose of -ve selection?

Answer 22

Remove B cells that have the potential to be auto reactive

Question 23

What happens in -ve selection?

Answer 23

Tests the BCR on b cells ability to bind tightly to self-antigens; those who bind too tight receive a death signal

Question 24

After the selection process that is the B cell now considered to be ?

Answer 24

Large pre-B cell

Question 25

Why is becoming a large preB cell important ?

Answer 25

It can pair with a surrogate light chain

Question 26

What are SLC made of ?

Answer 26

VpreB and Lambda5

Question 27

What does SLC partner with ?

Answer 27

Heavy chain to become a Pre-B cell recptor

Question 28

Why is this important ?

Answer 28

To determine if the heavy chain is functional

Question 29

What if it is functional?

Answer 29

Heavy chain can proliferate and pair with many light chains

Question 30

What does the B cell become now ?

Answer 30

Small pre-B cell

Question 31

Where do light chain rearrangements take place ?

Answer 31

On either Kappa or Lambda light chain

Question 32

What one rearranges first ?

Answer 32

Kappa

Question 33

When does it become a lambda chain?

Answer 33

Only if the kappa chain can not successfully bind

Question 34

Why is it crucial that the light chain can bind to heavy chain?

Answer 34

For a small pre-B cell to become an immature B cell which signals IgM BCR

Question 35

What happens when chains on BcR effectively pair ?

Answer 35

Folder immunoglobulin is exported out of the Golgi complex and expressed on the surface as a BCR

Question 36

What signals do BCR express ?

Answer 36

Survival signals into the developing B cell

Question 37

What B cells survive ?

Answer 37

Those which have successful rearrangement and have a functional formed IgM molecule

Question 38

What are the two signals ?

Answer 38

CD79a and CD79B

Question 39

Where do B cells continue to mature ?

Answer 39

Secondary lymphoid organs such and spleen and lymph nodes

Question 40

How do B cells enter such organs ?

Answer 40

The use of selections and bind addressing to enter directly or by squeezing through epithelial cells in high endothelial venules

Question 41

Where do B cells first enter ?

Answer 41

Paracortical region of the lymph node before migrating to the cortical region

Question 42

How does activation occur ?

Answer 42

When the antigen is crosslinked with BCR

Question 43

What happens during crosslinking ?

Answer 43

The intracellular chain, the side chains and CD19 cluster together

Question 44

What can a B cell now become ?

Answer 44

Plasma or memory cell

Question 45

Where are plasma cells found ?

Answer 45

Medullary cords of LN

Question 46

Where are memory cells found ?

Answer 46

Sub-capsular sinus of LN