Lecture 54 part 1 incomplete

Question 1

How is the antibody diversity?

Answer 1

The 2 chains have various gene types within the regions

Question 2

The variable domain region of the heavy chain is encoded by how many different segments?

Answer 2

3 separate segments

V, D, J

Question 3

The variable domain region of the little chain gene is encoded by how many different segments?

Answer 3

2 separate segments

V, J

Question 4

What happens during gene rearrangement?

Answer 4

Only one of the V, D, J heavy chain genes and 1 of the V and J light chain genes are selected

Question 5

what are the different gene types for the heavy chains and name their corresponding Ig

Answer 5

alpha IgA
delta IgD
epsillon IgE
Gamma IgG
Muon IgM

Question 6

What are the genes for the light chain?

Answer 6

Lambda or K

Question 7

Ig diversity comes from what 3 factors?

Answer 7

Multiple gene segments
2 light chain genes (k and Y) to choose from
Multiple VDJ and VJ genes

Question 8

Immunoglobin gene rearrangements occur during development of what?

Answer 8

B cells from pluripotent stem cells

Question 9

Where does Ig gene rearrangement take place?

Answer 9

In bone marrow

Question 10

Is Ig rearrangement dependent on antigen?

Answer 10

no

Question 11

Which chain arranges first?

Answer 11

Heavy then light

Question 12

Rearrangement of genes is accompanied by what?

Answer 12

Rapid division

Question 13

What is required for gene arrangement?

Answer 13

Enzymes

Question 14

What are the recombinations of V, D and J genes facilitated by

Answer 14

Recombinase enzymes, recombinase activating genes (RAG’s), Terminal deoxnucleotide transferases (TdT) and exonucleases

Question 15

Defects in genes result in what?

Answer 15

Block in recombination and an absence of circulating B cells

Question 16

Immature B cells may display what?

Answer 16

Auto-reactive antibodies

Question 17

Which region of the heavy chain is changed during isotype switching?

Answer 17

The constant region is changed while the variable region stays the same.

Question 18

Class/isotype switching does not affect what?

Answer 18

doesn’t affect the antigen specificity.

The antibody retains affinity for the same antigen but can interact with different effector molecules.

Question 19

How does isotype switching occur. Mention the Ig, receptors, regions, daughter cells that are involved

Answer 19

Naive mative B cells produce IgM and IgD, which are the first 2 heavy chain segments in the locus. These B cells then proliferate after being activated by the antigen. These cells can then encounter signalling molecules via their CD40 and cytokine receptors which leads to switching to IgG, IgA and IgE antibodies. Its only the constant region that is changed during isotype switching and so the antigen specificity remains the same. The daughter cells from the same activated B cell can then go onto produce antibodies of different isotypes.

Question 20

Overall describe the light and heavy chain composition

Answer 20

Light chain has variable region and constant region. Constant region is of lambda or k. Variable is V and J

Heavy chain has variable region and constant . Constant can be of 5 types. Variable is V D J