Chapter 4 sections 1-6 Flashcards
antibody structure
Stimulation of B cells
- Resting B cell with membrane bound Ig
- Ig on resting B cell encounters pathogen and binds
- This stimulates the B cell to become an antibody secreting plasma cell
Antibodies
are glycoproteins associated with constant resions of heavy chains
An antibody consists of
2 heavy chains and 2 light chains joind together by disulfide bonds
What kind of bond joins heavy and light chains
disulfide bonds
the antigen binding region is contained withing
the variable region
C terminal end
is made of a carboxy (constant region end)
the N terminal end is made of
amino end (antigen binding end)
The five types of antigens vary in their constant region these variations are
numbers of sugars attached to constant region
antibody that has fewest carbohydrates associated with constant region
IgG
antigen with 4 constant heavy domains instead of 3 (thus making them stronger)
IgM and IgE
FAB
two fragments that bind antigen following proteolytic cleavage of IgG
Fc
fragment that is crystallizable following proteolytic cleavage of IgG
light chains cant be
kappa or lambda isotypes (come from diff gene but functions the same)
heavy chains can be either
gamma, mu, delta, alpha, or epsilon isotypes
which chain determines the class of the antigen
heavy chain
Papain
enzyme that Preolyticly cleaves IgG into 3 fragments 2 FAB and one Fc fragment
Job of hinge on antigen
the hing is flexable and thus it gives the antigen its T or Y shape the hinge is made up of disulfide bonds that join the 2 heavy chains
Monomers
all classes of antibodies in their membrane bound form
also secreted forms of IgG, IgE, IgD
secreted forms of IgG IgE and IgD are called
monomers
Secreted form of IgM is a
pentamer
Secreted form of IgA
can be either a monomer or a dimer
Globular molecules
monomeric antibodies
they form 3 globular regions thus they are called globular molecules
Fab region
is made up of a constant region and a variable region. it consists of 2 beta-pleated sheets that are sandwichlike hidrophobic bonds in middle that hold sheets aka bread together
There is lots of back and forth folding
Variable region make up
3 hypervaiable (HV) regions which are flaked by framework regions(FR)
Frame work regions
flank hypervairable region but are less variable
this is the Beta pleated sheets
hyper variable regions occur at
the tip of the antibody molecule furthest from the C region.
this is the region that interacts with the epitope on the antigen
Epitopes
on surface of pathogen it is the precise point where antigen binds/reacts with antibody.
these occur on very tip of antigen
Multivalent antigen with differnt epitopes
a single antigen that has several different types epitopes thus different antibodies are produced to bind to the different epitopes (many antibody types produced for same antigen)
Multivalent antigen with a repeated epitope
the same antigen is presented in many places on surface of cell. requires only one type of antibody
Types of Antibody survaces
pockets
grooves
ectended/curved
spiked/knobs
2 types of epitope
linear
discontinous
how to clinically produce antigen for human use
immunize mouse with antigen harvest spleen to separate B cells fuse with myeloma cells only use hybrid growth Test for desired Antibody and specificity clone Bcell produces monoclonal antibody
flow cytometry
fast way to do a cell count
antibodies have florescent marker so when binds to pathogen laser detects florescence and thus counts # of antibodies in cell
Monoclonal antibody to treat Rx (autoimmune diseases)
make antibody in mouse then combinde variable region of mouse antigen with human constant region (chimeric) then only keep nessary part of mouse antibody to keep specificy (humanized)
chimeric antibody
combinde variable region of mouse antigen with human constant to treat autoimmune disease
humanized antibody
hen only keep nessary part of mouse antibody to keep specificy to treat autoimmune disease
