"Microbiology/Immunology Antibody Structure & Function" SANA Flashcards
Which immunoglobin class is the heaviest?
IgM
Which Immunoglobin is primarily responsible for the neutralization and protection against foreign bodies?
IgG
IgM is often found as a ______ (organization)
Pentamer
True or false? The light chains and heavy chains are identical to each other
False, they are different but one light chain in an antibody is identical to another light chain in an antibody (same for heavy chains)
Where is IgA usually found?
In mucus membranes because it can transport across the epithelium
Which immunoglobin is usually responsible for allergic reactions?
IgE
IgE is responsible for the sensitization of ______
Mast cells
Which antibodies does the fetus get directly from its mother?
IgG because they can transport across the placenta
Which antibodies can diffuse into extravascular sites?
IgG
Which immunoglobin class is the most stable? What is its half life in serum?
IgG; about 3 weeks
True or false? IgG can directly kill a bacteria without a complement system.
False: IgG does not directly kill bacteria alone, it binds to it and, in the presence of a complement system, can kill it.
How do natural killer cells use antibodies to target a cell?
Using antibody dependent cellular cytotoxicity where antibodies direct the NK cell to the target
IgG can cause the clumping of bacteria. What is this called?
Agglutination
Why can’t IgM aid in opsonization without the help of a complement system?
Because immune cells don’t have IgM receptors
Which immunoglobin is crucial in EARLY immune response?
IgM, its found as antigen receptors on naive B-lymphocytes.
What is holding the IgM pentamer together?
The J chain
IgA is found mostly as ____
Dimers
What is a secretory piece?
A protein that wraps around the IgA molecule as it passes through the epithelial cell and keeps it from being hydrolyzed.
In what secretions is the IgA usually found?
Mother’s milk, saliva, gut secretions
Where is the variable region found once the antibody has been cleaved? In the Fab region or the Fc region?
The Fab region
Why does the Fc region crystallize and not the Fab region?
The Fc region does not have a variable region and the structures can thus form crystals as they are constant to each other.
On which portion of the variable region of the antibody do the antigen bind?
The hypervariable region, which provides specific complementarity to the specific antigen.
