B Cell

Question 1

What are B cells?

Answer 1

A type of lymphocyte that produces antibodies

Question 2

What immune system do B cells belong to?

Answer 2

Adaptive immune system

Question 3

What happens if you do not have B cells?

Answer 3

No antibodies which increases the risk of infection

Question 4

What is an example of a disease caused by a lack of B cells?

Answer 4

XLA which is a mutation that prevent B cell development

Question 5

Where do B cells develop?

Answer 5

In the bone marrow

Question 6

What are the key stages of B cell development?

Answer 6

• Pro B cell
• Pre B cell
• Immature B cell
• Mature naive B cell

Question 7

What occurs in the pro B cell stage?

Answer 7

Heavy chain genes are rearranged

Question 8

What occurs in the pre B cell stage?

Answer 8

Heavy chain pairs with surrogate light chains

Question 9

What occurs in the immature B cell stage?

Answer 9

IgM is expressed

Question 10

What occurs in the mature naive B cell stage?

Answer 10

IgM and IgD is expressed

Question 11

How do B cells generate unique receptors?

Answer 11

V(D)J recombination

Question 12

What enzymes are responsible for V(D)J recombination?

Answer 12

RAG 1 and RAG 2

Question 13

How do B cells increase diversity further?

Answer 13

Junctional diversity

Question 14

What is junctional diversity?

Answer 14

Random nucleotide addition by TdT enzymes

Question 15

What is a BCR?

Answer 15

Membrane bound antibody on B cells that binds antigens

Question 16

What proteins help BCR signalling?

Answer 16

Igalpha and Igbeta

Question 17

What are the two main regions of an antibody?

Answer 17

• Fab region
• Fc region

Question 18

What is the Fab region?

Answer 18

Where the antibody binds antigens

Question 19

What is the Fc region?

Answer 19

Where the antibody binds immune cells and activates immune functions

Question 20

What are the five antibody classes?

Answer 20

IgM
IgG
IgA
IgE
IgD

Question 21

Which antibody is most abundant in serum?

Answer 21

IgG

Question 22

Which antibody is most abundant in mucosal areas?

Answer 22

IgA

Question 23

Which antibody triggers allergic reactions?

Answer 23

IgE

Question 24

How do naive B cells get activated?

Answer 24

By binding to a specific antigen

Question 25

What are the two types of B cell activation?

Answer 25

- T-dependent activation - T-independent activation

Question 26

What happens during T-dependent activation?

Answer 26

- B cell binds antigen - B cell presents antigen on MHCII to T cells - CD40-CD40L interaction activates B cell - Cytokines guide isotype switching and affinity maturation

Question 27

What is a germinal center?

Answer 27

A structure in lymph nodes where B cells improve antibodies

Question 28

What three key processes occur in germinal centers?

Answer 28

- Somatic hypermutation - Affinity maturation - Class switching

Question 29

What are the five main functions of antibodies?

Answer 29

- Neutralisation - Opsonisation - Complement activation - ADCC - Mast cell activation

Question 30

What is neutralisation?

Answer 30

Antibodies block pathogen entry

Question 31

What is opsonisation?

Answer 31

Antibodies coat pathogen and mark it for phagocytosis

Question 32

What is ADCC?

Answer 32

When antibodies trigger natural killer cells to kill infected cells

Question 33

What is mast cell activation?

Answer 33

Antibodies activate mast cells to trigger an allergic reaction

Question 34

Which antibodies activate the complement cascade?

Answer 34

IgM and IgG

Question 35

Which antibodies are involved in opsonisation?

Answer 35

IgG and IgA

Question 36

Which antibody is involved in ADCC?

Answer 36

IgG

Question 37

Which antibody is involved in parasite defense?

Answer 37

IgE

Question 38

What are memory B cells?

Answer 38

Long lived B cells that quickly respond to reinfection