Thrush- B Cell Activation

Question 1

aside from making contact with antigen, what else helps a B cell to class switch?

Answer 1

T cell help

Question 2

what signaling molecules interact with antibody to create a B cell receptor signaling site after the Ig has CROSSLINKED with the Ag?

Answer 2

Ig alpha and Ig beta

Question 3

what is the name of the surrogate L chain that acts as a place holder for the real L chain?

Answer 3

vPreB/ lambda 5

Question 4

can light chain rearrangement occur, while IgH rearrangement is still going on?

Answer 4

no. the heavy cell rearrangement must be shut off before the light chain is rearranged

Question 5

how are cancers caused in B cells?

Answer 5

when cell cycle regulatory genes move next to the Ig promoters and or enhancers. the B cell will then be constantly replicated

Question 6

what interacts with the ligand after Ig alpha and Ig beta start the signal cascade?

Answer 6

CD40 (CD154- this is what it is called when it binds ligand)

Question 7

the B cell has a receptor called CR2 (CD21), will bind to what in order to start signaling so that the B cell will recognize the microbe?

Answer 7

C3d… (this allows the molecule CD19 to send another signal into the B cell)

Question 8

the ITIM (immunoreceptor tyrosine phosphate inhibitory motif) creates the negative signal in the B cell to stop signaling, what does it bind too for this to happen?

Answer 8

CD22

Question 9

the atypical B cell is called a B1 B cell. what do they express on there surface? where are they most concentrated? and what type of affinity and cross rate do they have?

Answer 9

CD5
pleural and peritoneal cavities
low affinity and high rate of cross reactivity (polyspecificity)

Question 10

do B-1 cells require T cell for help? and how does it renew?

Answer 10

no

self-renewal

Question 11

do B-1 B cells contain diverse V-regions?

Answer 11

nope. they have restricted V regions

Question 12

are production of IgG, affinity maturation and quicker response characteristics of primary response?

Answer 12

nope. secondary response (memory response)

Question 13

in the lymph node what occurs in the primary follicle?

Answer 13

B cells activation

Question 14

what type of cell does not present Ag to T cells, but rather “traps” antigen?

Answer 14

follicular dendritic cells

Question 15

what are the functions of antibodies?

Answer 15

pathogen neutralization, complement (C) fixation, antibody-dependent cellular cytotoxicity, opsonization and inflammation

Question 16

what is the difference between pro-B cell and pre-B cell? and what do they have in common?

Answer 16

both are early stages of B cell development.
Pro-B cell:H chain (D-J) gene rearrangement
Pre-B cell: H chain with surrogate light chain on B cell surface (V-DJ rearrangement)

Question 17

what is the purpose of light chain editing?

Answer 17

if B cells are self reactive (IgH and IgL bind) then the V and J genes on the light chain can be rearranged. (remember if they dont rearrange it can lead to an anergic response or autoimmune response)

Question 18

what is the precursor to the pre B cell that indicates that the heavy chain is completed?

Answer 18

IL-7

Question 19

do both pro B cells and pre B cells express CD45R+, RAG1/2, Tdt and Ig alpha/ Ig beta?

Answer 19

pre B cells lack Tdt expression. but both express the other three

Question 20

what do cytokines IL-4 and IL- 5 do to B cells?

Answer 20

isotype switch to IgE production