Ab diversity/T cell development Flashcards
2 different variability regions of antibodies
antigen binding - highly variable
biological activity- limited variability
part of heavy and light chain that combines to recognize an antigen
Fab region
region of antibody that has more to do with the different classes of antibodies
Fc region
intra and inter chain linking of antibodies is through ____ bonds
disulfide
reason why antigen/antibody binding is highly selective?
to discriminate between self and non-self / discriminating between different types of pathogens
antigen/antibody binding is mediated by ____ forces with no ___ binding
weak; covalent
the combination of ____ on both light and heavy chains constitutes the antigen-binding site of Ig
CDRs (complementarity-determining regions) VH or VL
theory that says cells respond to antigen by imprinting the shapes of the antigen and make antibodies accordingly
instructive theory
theory that says antibodies are pre-made and antibody specificity is generated randomly, and antigen selects the correct antibody
selective theory
there are two genes used to make the light chain: ___ gene on chromosome ____ and ____ gene on chromosome ____
lambda gene on chromosome 22
kappa gene on chromosome 2
the heavy chain comes from ____ gene on chromosome ____
one gene on chromosome 14
the Ig gene is made up of different _____
segments
in the presence of all segments, B cell is not ____ and it will not ____
productive; make Ig (there is no gene product)
____ and ____ of different segments allow you to generate specific antibodies
deletion; recombination
there is no Ig production in ____ cells
pro-B
DNA which is passed down through the gametes before it is modified by somatic recombination or maturation
germ line DNA
____ contain germ line DNA
pro-B cells (bone marrow stem cells)
the gene loci for Ig production in Pro-B cells are _____ due to lack of _____
non-functional; open reading frame
____ and ____ have to interact to make ____ work for DNA recombination
enhancer; promotor; RNA polymerase
after DNA recombination, the ____ can influence the ____
enhancer; promotor
only after _____ the cell will do ____ to make antibody
recombination; transcription
there are about ___ Vk segments, ____ Jk segments, and ___Ck unit in kappa chain production
30; 5; 1
after deleting ____, B cell mRNA contains a completely _____ that consists of _____
intron; open reading frame; VxJyCk
the variability of k chain by recombination is _____
30x5 = 150
there are about ____ Vlambda segments, ____ Jlambda segments, combined with ____ Clambda units
30;7;7
the variability of lambda chain by recombination is ____
30x7 = 210
what regions join together to form the heavy chain?
VDJ
diversity of the heavy chain
V (51) x D (30) x J (6) = 9180
lambda and kappa chain variability
150 + 210 = 360
in production of the heavy chain, a few nucleotides may be inserted between D and JH and between VH and D to create further diversity; this is called _____
N-nucleotide addition
after ____, the V,D,J genes in B cells can make single base changes often at the region of ____
antigen stimulation; CDR
single base changes in V,D,J genes is called ____ which occurs to increase ____
somatic mutation; affinity of antibody (affinity maturation)
manipulation of ____ region genes results in class switching of the antibody
constant
alternative splicing produces both ___ and ____ for class switching of antibody
IgD; IgM
alternative splicing only occurs in ____
mRNA
deletion of ____ gene in DNA results in expression of ____; this is called the _____ process
M, D, G3; IgG1; loop and cut
____ are made in similar way as antibodies
T cell receptors
precursors of T cells travel from the ____ through the blood to the ____
bone marrow; thymus
selection processes eliminate _____ and promote survival of thymocytes whose TCRs bind ____ molecules with ____
self-reactive thymocytes; self MHC; low affinity
selection occurs in the ____
medulla of the thymus
result of positive selection
thymocyte is rescued from apoptosis and converted to single positive
in order to undergo positive selection, TCR cell must:
recognize MHC and have low affinity for self-antigen
If TCR does not recognize MHC molecule it will:
undergo apoptosis (lack of positive selection)
if TCR recognizes MHC and binds with high affinity it will:
undergo apoptosis (negative selection)
