Immunoglobulins-Thrush Flashcards
How many epitopes can each antibody bind to?
ONE!
how many different types of antibodies (with different antigenic specificities) can a plasma cell produce?
plasma cells can only produce antibodies with ONE antigenic specificity (one type of antibody)
How is electrophoresis helpful in diagnosing patients with multiple myeloma (cancer of a B cell producing monoclonal Ig)?
In a normal person, the electrophoresis would show a broad gamma peak, representing the variety of antibodies present in the body.
In multiple myeloma, the cancerous B cell will mutate, leading to mass production of identical antibodies–> this leads to a more narrow (because there is less of a variety of B cells present) and very high “M peak” (proliferation of the mutated antibody
What are Bence-Jones proteins? When and where would they be found and in what type of patient?
in myeloma patients, there is an over-production of antibodies that causes there to be free heavy and light chains present. The free light chains are small enough to get through the kidneys and will be excreted in the urine as Bence-jones proteins.
What differentiates the 5 different classes of antibodies?
the heavy chains
Where is variability in the antibodies found? which makes the most contact with the Ag?
complementarity determining regions (CDR): CDR1, CDR2, and CDR3
(AKA hypervariable regions)
CDR3 makes the most contact with the antigen
Which three antibody types are monomers?
IgG, IgD, IgE
Which antibody class is a dimer?
IgA
Which antibody class is a pentamer?
IgM
Which antibody class exists in the lowest concentration in the blood? What type of reactions is it active in?
IgE is involved in allergic reaction responses
Which antibody classes can activate complement?
IgG and IgM
Which antibody class is involved in secretions? What component if this antibody assists in the secretion and how does this component function?
IgA
A polypeptide called secretory protein associates with IgA and protects it from its harsh environment and digestive enzymes.
When SC is secreted from B cells, it is dimerizes. when it interacts with the poly-Ig receptor on specialized cells lining the mucous membrane, these IgA bind to the poly-Ig receptor and are internalized in the epithelial cell. where it will be secreted into the lumen and considered to be the secretory component. SC can bind to the bacteria and inhibit its ability to attach, preventing disease
Which antibody class is the highest concentration in the blood?
IgG
Which two antibody classes have an extra constant region domain in the heavy chains?
IgE and IgM
Which antibody class can cross the placental barrier?
IgG
In a mature B cell that has NOT been exposed to an antigen yet, which Ig’s are present on the cell’s surface?
IgM and IgD
Which Ig’s are normally present in the brain?
NONE! Ig in the brain=damage to the blood brain barrier
What is avidity? Which antibody has the highest avidity?
Avidity is the strength of binding. IgM has the highest avidity because it has 10 arms which allow stronger binding to the antigen
What antigen is first produced during primary exposure?
IgM
Which antibody makes up the highest concentration in the body?
IgA
Which antibody is associated with allergies and how does this work?
IgE
when individuals are exposed to a particular antigen, they class switch to IgE and not another isotope. THis then interacts with mast cells and basophils and when they are exposed to the antigen, will develop an allergic reaction (degranulation) (AKA type I hypersensitivity)
What are antibody isotopes?
– classes
determined by C-regions of the H-chain
some describe light chain isotypes as well (kappa and lambda)
what are allotropes?
allelic forms of the same protein that can vary within a species
usually 1-2 a.a. changes
What are idiotypes?
due to the variable region (e.g. CDRs) of the Ig (differences in a.a. sequences due to variable binding to Ags)
essentially a clonal marker for a given B cell (which epitope a given antibody binds to)
What determines the function of the antibody?
isotype (the C-regions and the H-regions)
