extra lect 5 Flashcards
where is the n terminus on the antibody
on the variable end
how many disulfide bonds in antibodies
4
what results in two heavy chain and two light chains
mercapteothanol reduction
what results in two Fab and one Fc
papain reduction
what resulst in an Fab connected and one Fc
pepsin digestion
secreted and membrane ig ahve same _ and different _
same fab different fc
antibodies interact w antigens at
complementarity detemrining regions (loops n Fab egion)
what is the part of the antibody that isnt CDR called
framework region
what kind of interactions mediate ab and ag interaction
non covaelnt
ionic
h bond
vdw
most abundant protein in blood
albumin
electrophoresis separates proteins by
charge and mass positive closer and -ve farther
what reactions prove that Abs are substances
agglutination rxns
shows us that the valency of Abs AND antigens is important to have cross linking at zone of equivalnce and prevent clotting
biological consequences of ab binding
activation of complement
transcytosis
opsonization
degranulation
ADCC
wjat os trancytosis
moving ab across epithelial layers
where does generation of ab diversity occur
in bone marrow
what is the igL called
bene jones proteins
what are the two types of light chains
kappa
lambda
how many possible c gene alleles are there
4 bc two light and two parents
where is the 12bp cluster and 23 bp cluster
12- v
23- j
how does heavy chain rearrangement work
d and j THEN v w the d+j
order of b cell types
lymphoid stem cell
pro
pre
immature
niave
matuer
joining of DNA segment on B cell is regulated by
RSS ergions on the DNA that flank the segments
12/23 rule- 12 can only join w 23
combinatorial diversity
v/d/jj
junctional diversity
flexibility of RSS joinoing and P and N nucleotide addition
what is an episome
the garbante signal joint formed from RSS joining by RAG 1/2
occurs if the segments lie in the same direction
RAG1/2
enxymes that recognize RSS and cut the DNA
how do RAG 1/2 work
bind- form hairpin
cut the hairpin- form P nucleotide
N nucleotide addition by Tdt
what enzyme cleaves the hairpin
artemis
where does N nucleotide additoin occur
in the heavy chain only NOT IN LIGHT CHAIN
what happesn if the gene segments are in opposite directions
the signal joint remians i nthe genomic DNA and must be ignored through RNA processing
RNA processing is how we have secreeted and membarne bound forms of the same Abs
diversity of heavy and light chains occurs
independenty of each other
what are the gene segments that make up the heavy chain
VDJ and Cu
apoptosis vs necrosis
apoptosis- programmed cell death/ suicide
-involves phagocytes
necrosis- disintegration, and release and inflamamtion
what ensures only one Ab per B cell is expressed
allelic exclusion and productive rearragement
what activates B cells
antigen binding
12RSS
23RSS
12- one turn
23- two turns
where are CD markers expressed
on b and t cels
tCR a chain is like what and TCR b chain is like what
a- light
b- heavy
chaperone for the TCR
CD3
invariant
valency and conformation of T and B cell receptors
B can bind to two things and has 4 chains
flexible
T can bind to one thing and has two chains
rigid
what are the differences bw BCR and TCR
TCR not secreted
affinity of binding doesnt change when bound
valency and conformation
antigen recognition- T cells require MHC
what is not involved in TCR diveristy that is in BCR divesity
SHM
Somatic gene conversion
what induces TCR diversity
multiple germ line segments
combinatorial VDJ
combinatorial paiting of a and B chains !!!!!
receptor editing
junctional and insertional diversity
what dont TCR have that BCRs have
RNA splicing
what antibody is found on immature B cells
igM
B cell anergy
state of unresponsiveness where B cells that have self reactive Ab go to periphery
what happens if RAG genes are mutated
NO B OR T CELLS
B cell receptor editing
mosty on light chain can be on heavy
intercation of BCR w self Ag in BONE MARROW
