Immunoglobulin Flashcards
Albumin
Most abundant plasma protein
Maintains osmotic pressure
Transports FAs and metals (has hydrophobic pockets and will bind many hydrophobic drugs)
Malnourished children will have edema in stomach and face if not making enough albumin
Fibrinogen
Blood coagulation
Epitope
Small specific portion of that protein that the antibody recognizes
IgG
Most common
Seen in many therapeutic drugs
Heavy chain = gamma
IgA
Tears, saliva, protects external body surfaces
Dimer
Mucosal surfaces
Alpha
IgM
Produced early in immune response, and exists as a pentamer
Alot of binding sites
Use IgMs to see how long an antigen has been in your system
Mu
IgD
Exist on lymphocytes
Unknown function
Delta
IgE
Persist at low levels in serum, functional for parasitic reactions
You can have problems with allergeric reactions if don’t have enough IgE
Epsilon
Heavy chains
Twice as long as light chains
Each Ig has two heavy chains connected by disulfide bonds
Light chains
Either kappa of lambda
Never a mixture
Beta-pleated sheets in Igs
H-bonds between different sequences of AAs
Resulting in a pleated structure
Important because the terminal AA will end on different levels which will fold up…
Creates a hydrophobic face and hydrophilic face
‘Beta-sandwich’
Immunoglobulin fold
Two sheets come together
Greasy parts come inside
This is how Igs come together = supersecondary structure
Variable regions
N-terminal region
Supersecondary structures - where antigen binds
Also known as = ‘Fab region’
CDR
Complementary determining region
Where sheets are connected by loops
Where antigen binds
Regions of HYPERVARIABILITY….explains epitope diversity
‘Fc Region’
Heavy chains not in the variable region are known as this….
Property to crystallize and control the effector portion of the Ig
ELISA
- Coat surface with antigen
- Fill in the rest of the space with unspecified proteins that will not interact with the experiment at all
- Incubate a primary antibody that is specific to the antigen
- Incubate a secondary antibody that is specific to the primary antibody (with an enzyme bound to it)
- Incubate substrate that enzyme has a affinity for
- Have enzymatic product be fluorescent
Darker = more concentration of antigen..
Therefore ELISA allows for quantification
Western blot
Proteins are separated by size in a denaturing SDS gel
Total proteins can be visualized by staining the gel with a dye that binds proteins
Compare to where bands show up in sample gel
Able to determine size of antigen
ChIP assay
Investigate the interaction between protein and DNA in the cell
It can tell whether specific proteins are associated with specific regions in the genome
Useful to determine regions of genome that epigentic modifications occur
—> cross-link proteins to DNA…shearing the DNA into short pieces and then using antibodies to immunoprecipitate proteins from the complex mixture
Polyvlonal antibodies
Your body will make a bunch of antibodies for the foreign protein in your body by B-cells
Not all of them will bind to an epitome …
So may have 100s of antibodies binding to other pieces
—> mixture of antibodies that recognize different epitomes
Monoclonal antibodies
More homogenous
All antibodies recognize the same epitome
There are naturally occuring monoclonals antibodies
Multiple Myeloma
B-cells expand and get large concentration of the IgGs in your serum
Patients have high M protein concentration in serum,
They secrete light chains in urine because they cant reabsorb all that was produced = BENCE JONES protein
Symptoms = elevated Ca2+ levels, renal failure, bone lesions (CRAB), and anemia
ScFv
Binding activity is in the end termianl (SCFV)
First variable region of the light and heavy chains are linked through a peptide bond
This is a molecule that has thrown away everything except the light and heavy chain with N-terminal and the CDR
It still retains the binding properties of the Ig
