Generation of Antibody and TCR diversity and selection

Question 1

What are the differences between primary and secondary (anamnestic) immune responses?

Answer 1

adaptive immune response
primary- delayed; biphasic response IgM, then IgG; expansion of clones of effector B cells, develop into plasma cells
secondary (anamestic)- shorter lag period; extended plateau, slower decline; use of memory B cells; affinity maturation

Question 2

What is the concept of clonal selection?

Answer 2

one B cell will divide into many daughter cells that produce antibodies that all have the same variable region; antibodies of different isotypes that react with the same epitope on an antigen

Question 3

What parts of the immune system maturation happen in the primary lymphoid organs? Is this antigen dependent or independent?

Answer 3

Primary lymphoid organ- B cells mature; antigen independent

Question 4

What parts happen in the secondary lymphoid organs? Is this antigen dependent or independent?

Answer 4

Secondary lymphoid organs- B cell divides in response to antigen and T cell help; antigen dependent; creation of plasma cells and memory B cells

Question 5

What is the order of development of the BCR?

Answer 5

a

Question 6

Why is the order important?

Answer 6

a

Question 7

Explain allelic exclusion.

Answer 7

a

Question 8

List the different mechanisms during the generation of BCR that contribute to diversity? (7 different ways)

Answer 8

1. genetic diversity
2. combinatorial diversity
3. recombinational sloppiness
4. different assortment of H and L chains
5. N-region diversity
6. somatic point mutations
7. chance of 10^7 different antibody molecules

Question 9

Understand how each mechanism contributes to diversity of BCR (increases the number of antigens an individual can recognize)?

Answer 9

a

Question 10

Understand the roles of RAG1 and RAG2, DNA-PK, and TdT

Answer 10

a

Question 11

What would happen if RAG1 and RAG2, DNA-PK, and TdT were absent?

Answer 11

aa

Question 12

What is somatic hypermutation (affinity maturation)?

Answer 12

a

Question 13

In which lymphoid organ does somatic hypermutation take place?

Answer 13

germinal centers (secondary lymphoid organs)

Question 14

Does somatic hypermutation require antigen?

Answer 14

yes, happens during fast clonal expansion

Question 15

How do animals with limited number of Variable regions compensate to increase their diversity? Does it require antigen?

Answer 15

pg. 45

Question 16

What part of the antibody molecule changes during class switching (variable region, constant region, heavy chain, or light chain)?

Answer 16

constant region of the heavy chain

Question 17

Why do antibodies switch classes?

Answer 17

signal splicing, new constant region has expressed isotope

Question 18

Why can you not switch back to IgG from IgA?

Answer 18

info has been spliced out and removed from cell

Question 19

What signals the cells to switch classes?

Answer 19

cytokines in microenvironment

Question 20

Which chains form first in TCR maturation? Why do these chains form first?

Answer 20

70

Question 21

What are the similarities and differences between BCR and TCR generation?

Answer 21

72 (70-10)

Question 22

Understand education of T cells in the thymus. What is positive/negative selection? What does this protect against?

Answer 22

71

Question 23

Compare and contrast TCR and BCR

Answer 23

72