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Terms in this set (17)

somatic hypermutation
- increases point mutations initiated by AID enzyme throughout heavy and light chain variable regions
- the way the adaptive immune system evolves with the pathogen in our bodies.
- controls immunoglobulin affinity maturation and increases the affinity pool of the antibody against the antigen
- somatic hypermutation turned off if alphabeta made before gamma delta
- somatic hyper mutation high in B2 cells
- somatic hypermutation occurs at the DNA level
- occurs in germinal center of secondary lymphoid tissue, where B cells migrate to become activated and undergo somatic hypermutation
- T helper cell interaction with B cells trigger somatic hypermutation--> T dependent
- binding of CD40L on a naiive B cell drives somatic hypermutation
***occurs in only B cells

somatic recombination:
- combination of randomly selected gene segments--> creates combinational diversity
- heavy chain undergoes somatic recombination first in B cells
- 12/23 rule (12 spacer can only join to a 23 to ensure gene segments arranged in correct order)
- NO somatic recombination in HLA genes
- RAG1 and RAG2 cut DNA and initiate somatic recombination in pro-B and pre-B cells
- daughter cells can skip somatic recombination
***both B and T cells

isotype switching:
- can switch from igM to igG or any other isotope in order to high current infection
- DNA rearrangment that matches the rearranged variable region with the new C region
- will occur in germinal center with native B cells
- T helper cell interaction with B cells trigger isotope switching --> T dependent
- T follicular helper cells help isotope switch
- IL-5 produced by TH2
- INFgamma and IL-4 influence isotope switching
- TGF- beta drives --> igA
- APRIL is an isotype switch factor for giga
***just in B cells

affinity maturation:
-binding of CD40L on a naiive B cell drives affinity maturation
***just in B cells

Junctional diversity:
***both B and T cells