B cells

Question 1

Are B-cells part of the humoral or cell-mediated immune response?

Answer 1

humoral response

Question 2

what do B-cells produce?

Answer 2

Produce immunoglobulins

Question 3

immunoglobulins that remain on the surface of B cells are known as what?

Answer 3

B-cell surface receptors (BCRs)

Question 4

immunoglobulins that are secreted are known as ???

Answer 4

antibodies

Question 5

The following describes B1 or B2 cells?
- Appear early in foetal development
- Comprise 5% of all B cells
- Self-renewing in tissues outside the central lymphoid organs

Answer 5

B1 cells

Question 6

The following describes B1 or B2 cells?
- AKA “conventional B cells”
- Develop in bone marrow
- Populate blood and lymphoid tissues
- Activated in secondary lymphoid tissues

Answer 6

B2 cells

Question 7

How are B-cells activated after they leave the bone marrow carrying a unique surface receptor?

Answer 7

Activation occurs when the surface receptor encounters the relevant external antigen which stimulates rapid proliferation of the B-cell and antibody production

Question 8

What occurs if a naive mature B-cell does not encounter an antigen after leaving the bone marrow carrying a unique surface receptor?

Answer 8

it will undergo apoptosis within a few weeks

Question 9

differentiation of B-cells results in
- ???
-???

Answer 9

• memory B cells
• Plasma B cells

Question 10

Step 1 of b-cell development:
B-cells precursors undergo ??? in bone marrow

Answer 10

immunoglobulin gene rearrangement

Question 11

Step 2 of b-cell development:
B-cells undergo negative selection process in bone marrow whereby immature ??? are removed

Answer 11

B-cells bound to self-cell surface antigens (self-cell reacting B-cells)

Question 12

Step 3 of B-cell development:
mature B-cells migrate to ???

Answer 12

peripheral lymphoid organs and activate when bound to foreign antigen

Question 13

Step 4 of B-cell development:
activated B-cells differentiate into ???

Answer 13

plasma and memory cells.

Question 14

What are B-cell receptors?

Answer 14

Immunoglobulins bound to B-cell surfaces. Comprises 4 polypeptide chains linked by disulphide bonds (2 light and 2 heavy chains). Associated with 2 other chains, Igα and Igβ (disulphide-linked) and involved in cell signalling

Question 15

B-cell activation Thymus independant pathway:
typically a response to ??? and does NOT require direct contact with T(h) cells but DOES require recognition of PAMPs by ??? on B cells

Answer 15

bacterial endotoxins
pattern recognition receptors

Question 16

B cell activation Thymus dependant pathway: more common, requires direct contact with ??? and induces antigen-specific antibody response = long-lived plasma & memory B-cells

Answer 16

T-helper cells

Question 17

TRUE or FALSE: both thymus dependant and independant pathways of B-cell activation require cross-linking of B-cell receptors. If only one BCR binds an antigen = NO activation

Answer 17

TRUE

Question 18

which subset of B-cells are usually produced from thymus-independant activation? B1 or B2?

Answer 18

B1

Question 19

Antigens of thymus-DEPENDANT or INDEPENDANt b-cell activation are generally microbial cell wall components or polysaccharides

Answer 19

independant

Question 20

Do thymus dependant or independantly activated B-cells induce weaker, less specific
antibody responses, are short-lived plasma cells producing IgM, and have no ability to class switching

Answer 20

thymus-independant

Question 21

the antigens of thymus-dependant activated B-cells are ??? and induce antigen specific antibody responses. Produce long lived plasma B cells and memory B cells

Answer 21

most proteins

Question 22

Co-stimulatory molecules that are needed for B-cell activation include:
- Signal 1: Antigenic peptide presented by B cell MHC class
II molecules to ???
- Signal 2: B cell CD40 interacts with
- Signal 3: Induces the release of ???(IL-4), that stimulate B cell ???receptors (IL-4R)

Answer 22

• TH cell
• TH cell CD40L
• cytokines

Question 23

TRUE or FALSE: B and TH cells need to recognize the same antigen for activation (but not necessarily the same epitopes)

Answer 23

TRUE

Question 24

TRUE or FALSE: Secondary antibody responses (responses to repeated exposure to the same antigen) are faster and more specific than primary antibody responses

Answer 24

TRUE