Antibody Diversity Flashcards
RAG-1/2
Recombination activation genes
Mutation in these leads to host who is susceptible to a large variety of pathogens due to low number of B and T cells
somatic recombination
generates huge B cell repertoire, permanently alters the gremline DNA
kappa chain
chromosome 2
lambda chain
chromosome 22
heavy chain
chromosome 14
Heavy chain somatic recombination
D recombines with V
VD recombines with J to produce VDJ which encodes the variable region
VDJ recombines with C
occurs first before light chain recombination
Light chain recombination
V recombines with J
VJ is the variable region
VJ then recombines with C
kappa occurs first then lambda
terminal deoxynucleotidyl transferase (Tdt)
catalyzes the addition of random nucleotides between the gene segments that are joined
(heavy chains of B cells and beta chains of T cells only)
somatic hypermutation
when B cell proliferates it accumulates mutations affected the variable region, those mutations that confer better specificity for antigens are selected for resulting in affinity maturation
T/F class switching only changes the constant regions of the heavy chains?
true
T/F class switching affects the function of the antibody but not the specificity?
true
Why is class switching to IgD not possible?
No switch region precedes it
activation-induced cytosine deaminase (AID)
catalyzes recombination events leading to class switching also required for somatic hypermutation
Class switching is driven by ____
T helper cells
Hyper IgM syndrome
due to a genetic deficiency of AID, can’t class switch