#4 - Life of a B Cell: Building Up the Army

Question 1

what are the subchains of the heavy and light chains that contribute to their specificity?

Answer 1

VDJ heavy (D+J, then V+DJ)
VJ light

Question 2

what is the intracellular component of the BCR called?

Answer 2

CD79

Question 3

what is the intracellular signaling component of CD79?

Answer 3

ITAM

Question 4

what are the three histopathic identifiers of B cells?

Answer 4

CD19, 20 and 22

Question 5

what are the five steps of B cell production? (just the names)

Answer 5

stem cells
pro-B
pre-B
immature B
mature B

Question 6

what is the defining characteristic of a pro-B cell?

Answer 6

CD19 and IL-7R

Question 7

what is the defining characteristic of a progenitor lymphoid cell?

Answer 7

CD34

Question 8

what is the defining characteristic of a pre-B cell?

Answer 8

CD79 and CD20, has heavy chain inside and surrogate light chain inside

Question 9

what is the defining characteristic of an immature B cell?

Answer 9

expression of the heavy and light chain on the surface

Question 10

where are B cells developed in the fetus?

Answer 10

in the liver

Question 11

what marker do fetal B cells carry?

Answer 11

CD5

Question 12

what do mature B cells have that immature ones do not?

Answer 12

IgD receptors

Question 13

what are the two components of the surrogate light chain?

Answer 13

VpreB and Gamma-5

Question 14

how does a functioning mature heavy chain signal to the interior of the cell that it is functioning?

Answer 14

CD79

Question 15

if the mature chain expressed is not functioning then what happens?

Answer 15

RAG enzymes are expressed

Question 16

what is a “productive” B cell as regards tolerizing?

Answer 16

simply that it is strucutrally and functionally sound

Question 17

if the cell isn’t productive, what happens?

Answer 17

editing, the antibody is recycled up to three times in an attempt to make it sound; the light chain VJ sequences are re-arranged

Question 18

what happens if the antibody is self-reactive?

Answer 18

if it binds tightly - deletion

if it binds loosely - anergy

Question 19

how are the delta and mu chains created with the same VDJ combination?

Answer 19

differing RNA splice sites that only separate the M and D regions of the exons

Question 20

what type of diseases are caused by mutations in Ig-mu and CD79

Answer 20

immunodeficiency

Question 21

what two lab techniques can be used to type B cell tumors?

Answer 21

flow cytometry and IHC

Question 22

what is the target of the drug that knocks out B cells?

Answer 22

CD20