BLD 434 EXAM QUESTIONS AND ANSWERS WITH COMPLETE
SOLUTIONS VERIFIED GRADED A++
somatic recombination mechanism
- ?? signal sequence (?SS) binds to RAG(1&2) enzyme & directs enzyme to cut DNA
between the gene segments
- RSS's flank every V, D, & J gene segment in a v controlled sequence ("12/23 rule"-12
spacer can only join to a 23 to ensure gene segments arranged in correct order)
- heavy chain undergoes somatic ?? first in B cells
- NO somatic ?? in HLA genes
what is accomplished by somatic recombination
combination of randomly selected gene segments--> creates combinational diversity
somatic recombination cells
- occurs in B cells & T cells
somatic hypermutation mechanism
- increases point mutations initiated by AID enzyme throughout heavy and light chain
variable regions- chain V regions (not C regions) - this results in changes in the
nucleotide sequence coding for CDR loops
what is accomplished by somatic hypermutation
, somatic ?? is a crucial process for the adaptive immune system as it allows for the
generation of a diverse repertoire of antibodies that can specifically recognize and bind
to a wide range of pathogens
somatic hypermutation cells
- occurs in B cells(Ig affinity maturation = somatic ?? + clonal selection)
Isotype switching mechanism
-DNA rearrangment that matches the rearranged variable region with the new C region
-will occur in germinal center with naive B cells
-T helper cell interaction with B cells trigger this --> T dependent
-T follicular helper cells help this
-IL-5 produced by TH2
-INFgamma and IL-4 influence this
-TGF-beta drives --> igA
APRIL is an isotype switch factor for giga
what is accomplished by isotype switching
1. antigen binding of the antibody does not change
SOLUTIONS VERIFIED GRADED A++
somatic recombination mechanism
- ?? signal sequence (?SS) binds to RAG(1&2) enzyme & directs enzyme to cut DNA
between the gene segments
- RSS's flank every V, D, & J gene segment in a v controlled sequence ("12/23 rule"-12
spacer can only join to a 23 to ensure gene segments arranged in correct order)
- heavy chain undergoes somatic ?? first in B cells
- NO somatic ?? in HLA genes
what is accomplished by somatic recombination
combination of randomly selected gene segments--> creates combinational diversity
somatic recombination cells
- occurs in B cells & T cells
somatic hypermutation mechanism
- increases point mutations initiated by AID enzyme throughout heavy and light chain
variable regions- chain V regions (not C regions) - this results in changes in the
nucleotide sequence coding for CDR loops
what is accomplished by somatic hypermutation
, somatic ?? is a crucial process for the adaptive immune system as it allows for the
generation of a diverse repertoire of antibodies that can specifically recognize and bind
to a wide range of pathogens
somatic hypermutation cells
- occurs in B cells(Ig affinity maturation = somatic ?? + clonal selection)
Isotype switching mechanism
-DNA rearrangment that matches the rearranged variable region with the new C region
-will occur in germinal center with naive B cells
-T helper cell interaction with B cells trigger this --> T dependent
-T follicular helper cells help this
-IL-5 produced by TH2
-INFgamma and IL-4 influence this
-TGF-beta drives --> igA
APRIL is an isotype switch factor for giga
what is accomplished by isotype switching
1. antigen binding of the antibody does not change
