Generation of Antibody and TCR diversity and selection Flashcards
(23 cards)
What are the differences between primary and secondary (anamnestic) immune responses?
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
What is the concept of clonal selection?
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
What parts of the immune system maturation happen in the primary lymphoid organs? Is this antigen dependent or independent?
Primary lymphoid organ- B cells mature; antigen independent
What parts happen in the secondary lymphoid organs? Is this antigen dependent or independent?
Secondary lymphoid organs- B cell divides in response to antigen and T cell help; antigen dependent; creation of plasma cells and memory B cells
What is the order of development of the BCR?
a
Why is the order important?
a
Explain allelic exclusion.
a
List the different mechanisms during the generation of BCR that contribute to diversity? (7 different ways)
- genetic diversity
- combinatorial diversity
- recombinational sloppiness
- different assortment of H and L chains
- N-region diversity
- somatic point mutations
- chance of 10^7 different antibody molecules
Understand how each mechanism contributes to diversity of BCR (increases the number of antigens an individual can recognize)?
a
Understand the roles of RAG1 and RAG2, DNA-PK, and TdT
a
What would happen if RAG1 and RAG2, DNA-PK, and TdT were absent?
aa
What is somatic hypermutation (affinity maturation)?
a
In which lymphoid organ does somatic hypermutation take place?
germinal centers (secondary lymphoid organs)
Does somatic hypermutation require antigen?
yes, happens during fast clonal expansion
How do animals with limited number of Variable regions compensate to increase their diversity? Does it require antigen?
pg. 45
What part of the antibody molecule changes during class switching (variable region, constant region, heavy chain, or light chain)?
constant region of the heavy chain
Why do antibodies switch classes?
signal splicing, new constant region has expressed isotope
Why can you not switch back to IgG from IgA?
info has been spliced out and removed from cell
What signals the cells to switch classes?
cytokines in microenvironment
Which chains form first in TCR maturation? Why do these chains form first?
70
What are the similarities and differences between BCR and TCR generation?
72 (70-10)
Understand education of T cells in the thymus. What is positive/negative selection? What does this protect against?
71
Compare and contrast TCR and BCR
72
