Antigen Receptor B-Cell Development Lecture 5

Question 1

Early Pro-B cell

Answer 1

Heavy chain DJ rearrangment

Question 2

Late Pro-B

Answer 2

Heavy chain V-DJ rearrangement

Question 3

Large Pre-B

Answer 3

mu chain transiently at surface as part of pre-B-cell receptor. mainly intracellular
-mu heavy chain that is made binds a surrogate light chain and takes it to the surface

Question 4

small pre-B cell

Answer 4

V-J rearranging

-intracellular mu chain

Question 5

immature B-cell

Answer 5

IgM expressed on cell surface

Question 6

Mature B cell

Answer 6

IgD and IgM made from alternatively spliced Heavy chain transcripts

Question 7

What does RAG recognize and what does it do?

Answer 7

RAG recognizes RSS and cleaves the DNA between RSS and J or RSS and V, come together and get ligated

Question 8

What is a brec

Answer 8

B cell Recombination excision circle

Question 9

How do you get secreted IgM and membrane IgM with the same VDJ region? And IgM and IgD with the same VDJ region?

Answer 9

Alternative RNA splicing

Question 10

Does class switch happen in the bone marrow?

Answer 10

NO

-in the periphery, using aid mediated cleavage

Question 11

How do we get such a large repertoire of Ig?

3 reasons

Answer 11

1. combinatorial V(D)J gene joining
2. N nucleotide addition by TdT
3. Combinatorial association of H and L chains

Question 12

What does TdT do?

Answer 12

randomly puts on nucleotides to either side
can be anywhere from 1 to 30
changes antibody site-doesn’t require any additional DNA

Question 13

What are three ways these VDJ gene rearrangements may react with self, what happens to them?

Answer 13

1. multivalent self molecule
2. soluble self molecule
3. no self reaction

Question 14

What are three ways these VDJ gene rearrangements may react with self, what happens to them?

Answer 14

1. multivalent self molecule
   - clonal deletion-apoptosis or receptor editing
2. soluble self molecule
   - migrates to periphery-low mu expression-anergic bcell
3. no self reaction
   - migrates to periphery-mature b cell

Question 15

How is a multivalent self molecule given a second chance? (self-reactive b-cell)

Answer 15

receptor editing

• up regulate RAG-can rearrange again
• this can only happen in the light chain because in the heavy chain all the other d’s are deleted

Question 16

How is a multivalent self molecule given a second chance? (self-reactive b-cell)

Answer 16

receptor editing-light chain

• up regulate RAG-can rearrange again
• this can only happen in the light chain because in the heavy chain all the other d’s are deleted

Question 17

Is there a structural similarity of T cell receptor and Ig?

Answer 17

yes
T-cell receptor looks like Fab
Alpha and beta both have variable regions where the antibody interacts

Question 18

Is there a structural similarity of T cell receptor and Ig?

Answer 18

yes the T cell receptor looks like the Fab part on the Ig

• both alpha and beta regions on the t-cell have a variable region where the antibody interacts
• antibody (variableL and variableH) and T cell (variable alpha and variable beta)

Question 19

Is there a structural similarity of T cell receptor and Ig

Answer 19

yes the T cell receptor looks like the Fab part on the Ig

• both alpha and beta regions on the t-cell have a variable region where the antibody interacts
• antibody (variableL and variableH) and T cell (variable alpha and variable beta)

Question 20

Do T cells use TRECs like BRECs and RSS mediated by RAG?

Answer 20

yes