Immunoglobulin Flashcards
These are glycoprotein molecules that are produced by plasma cells in response to an immunogen and which functions as antibodies.
Immunoglobulin
What two chains are immunoglobulins composed of?
Heavy and light chains
What bond are the chains held together by?
disulfide bonds
What is the name of the part of an antigen that an antibody binds to?
Epitope
What is an idiotype?
The antibodies ability to bind to various different antigens (due to variations of amino acids sequences within the variable domains)
The function of the hinge region of an antibody
Improves flexibility
What part of the antibody controls the type of isotype (antibody)
The constant region
What structural scaffold supports the hypervariable regions
Framework
What are the hypervariable regions also called
Complementarity determining regions
Which specific part of the variable region has a direct interaction with the antigen?
The hypervariable region
What sequence in the hypervariable loops accounts for the diversity of antigens that can be recognized by a repertoire of antibodies?
Variable amino acid sequence
Genetic variation in the constant regions of antibodies, that differ between individuals within the same species is
Allotypes
The heavy chain constant region structures give rise to classes and subclasses called
Isotypes
What form does IgM exist when it is acting as a receptor on B-cells
Monomer
Monomeric IgM has very low affinity for antigen. True / False
True
What form does IgM exist when it is secreted from the plasma cells
Pentameric form
What antibody is the first to be produced in a primary immune response
IgM
Which constant region of the heavy chain of IgM initiates the activation of the classical complement pathway when bound to C1q
Cμ3
Which constant region of the heavy chain of IgM facilitates the uptake of opsonised antigens by macrophages when bound to C3b?
Cμ1
Which constant region of the heavy chain of IgM mediates multimerization
Cμ4
Which chain plays a crucial role in the formation of pentamers in IgM
J chain
What chain helps in the formation of dimers in IgA
J chain
How many subclasses does IgA exist in and what are they
2, IgA1 and IgA2
Where is the IgA1 subclass mostly found
It is mostly found in serum
Where is the IgA2 subclass mostly found
Found in mucosal secretions, colostrum and milk
What makes IgA2
B cells located in the mucosae
What are the general functions of immunoglobulins
Antigen Binding
Effector Functions
Which Ig is the third most common serum?
IgM
Which Ig is the first Ig to be made by a fetus?
IgM
Why is IgM a good complement fixing Ig ?
Due to its pentameric structure
Which Ig is a good agglutinating Ig?
IgM
IgM binds to some cells via
Fc receptors
In adults what conditions does IgM increase
Trypanomiasis
Malaria
Rheumatoid arthritis
Which Ig is the major Ig in serum and extra vascular space?
IgG
Which Ig is the only class of Ig that crosses the placenta?
IgG
Which subclass of IgG does not cross the placenta very well?
IgG2
In which conditons does IgG increase
Liver Disease
Severe Malnutrition
Rheumatoid arthritis
Which class of IgG does not fix complement very well?
IgG 4
Which subclassses of IgG does not cross bind equally well to Fc receptors?
IgG2 and IgG4
IgG and IgM activates how many distinct complement proteins?
11
Which Ig is the second most common serum Ig?
IgA
Which Ig are the first line of defense
IgM
How long does it take for IgG to reach significant conc. after exposure to a new antigen
About 10 days
What kind of bonds exists between antigens and antibodies
Van der Waals
Hydrogen bond
Hydrophobic
Ionic salt bridge
Which class of Ig is the major class of Ig in secretions
IgA
Which class of Ig does not fix complement unless aggregated
IgA
Which type of cells does IgA bind to?
PMNs and some lymphocytes
In what condition does IgA increase and decreases
Cirrhosis of the Liver
Malabsorption Syndromes
Which class of Ig is found in low levels in serum
IgD
Where is IgD primarily found?
The surface of B cells and they act as cell surface receptors
Which class of Ig doesn’t bind complement
IgD
In What conditions does IgD increase
Chronic infections, IgD myelomas
Which class of Ig is the least common serum Ig?
IgE
Why is IgE considered as the least in serum?
It binds to Fc receptors on basophils and mast cells even before they interact with antigen
Which Ig is involved in allergic reactions?
IgE
How are IgEs involved with Allergic reactions
Binding of the allergen to the IgE receptor on Basophils results in the release of various pharmacological receptors that lead to allergic symptoms
Which Ig does not fix complement?
IgE
Where are B cells produced?
Bone marrow
The two stages of B cells response
Primary immune response
Secondary immune response
During immune response the B cells change into what two form of cells?
Memory and plasma cells
Which type of cell cause a change in form of the B cells?
T cells
Cells that have been engineered to produce a desired antibody in large amounts is called?
Hybridoma
What are the methods of purifying monoclonal antibodies
1.
Filtration for larger particles
2.
Ultrafiltration esp. for low concentration samples
3.
Chromatography
study the Elisa slides again
What is used to fuse B cells with myeloma cells
PEG - polyethylene glycol
