Chapter 5 Antibody Structure and Function
What did Georges Kohler and Cesar Milstein discover?
a technnique to produce antibody arising for a single B cell by fusing it with a myeloma cell
What is the difference between the two chains Kappa and Alpha?
amino acid sequence
What serves as the antigen recognition unit of the immunoglobulin
aminoterminal end of the L and H chain
What is a hypervariable region?
antigen captured by small number of amino acids at specific locations
Describe the L chain?
between 200 and 220 amino acids. kappa or lambda
What is the function of IgE?
binds to Mast cells and allergic reactions and triggering acute inflammatory response
What does pepsin do?
cleaves IgG
What are the 4 main functions of IgM
complement, agglutination, opsonization, toxin neutralization
What is Fab
consist of one L chain and one half H chain for antigen binding capacity
What region of the H chain gives the immunoglobulin its name?
constant region
The variable region is held together by what?
disulfide bonds
Which WBC plays a role similar to IgE
eosinophils
What kind of spaces can cross the placenta?
extravascular spaces because of high diffusion coefficient
What does FAB stand for?
fragment antigen binding
What does Fc mean?
fragment crystallizable
What is the function of the Fc fragment
functions in opsonization and complement fixation
what is the hinge region?
high content of proline content that allows the antigen binding sites to bind
What happens when two adjacent IgE molecules bind to an antigen?
histamine and heparine are released inducing a type I immediate hypersensitive reaction
What are the 5 major functions of IgG
immunity for the newborn, fixing complement, opsonization, neutralizes toxins, agglutination and precipitation
What is a gamma globulin?
immunoglobulin
what is the carbohydrate portion?
immunoglobulin area that aids in increasing solubility, providing protection against degradation, and enhancing functional activity
what is an antibody?
immunoglobulin or glycoprotein found in the serum portion in the serum
When was IgD discovered?
in 1965 when a patient was diagnosed with multiple myeloma
What is an effector function?
initiation of the complement cascade
What are the 2 types Bence-Jonce proteins?
kappa and lambda
Where are the plasma cells in IgE primary located?
lungs and skin
What does the presence of IgM membrane indicate?
lymphoctes as mature B cells
What is the function of IgA?
maintains the health of newborns in breastmilk, mucous
Which WBC's have receptor for IgA?
neutrophils, monocytes, and macrophages
What is papain?
proteolytic enzyme used to cleave IgG. Two fab and 1 fc
Where is the IgA antibody found?
respiratory, intestinal mucosa, milk, sweat, and tears
What controls the synthesis of a particular immunoglobulin?
several genes via a random selection process
Which end of the aintibody is the variable region?
the terminal end
What is the side-chain theory?
theory postulated my Paul Erlich that certain cells have specific receptors for antigen that were present before contact with antigen occured
What is an isotype?
unique amino acid sequence common to all immunoglobulin molecules of a given class
What is an idiotype?
variable portions of each chain unique to specific antibody molecule
Can IgA act as an opsonin?
yes
Describe the structure of an immunoglobulin
2 Heavy H (Fc) and 2 Light chain L (Fab). Each chain has a variable and constant region
monoclonal antibody
B cells preprogrammed to synthesize specific antibodies that are used for diagnostic testing
pepsin
Breaks proteins into smaller polypeptide fragments. Cleaves IgG
What did dryer and bennett propose as a solution to the clonal selection theory?
Constant and variable portions of immunoglobulin chains are actually coded for by separate genes
What is clonal selection?
Idea that individual lymphocyes are genetically programmed to produce one type of immunoglobulin and that a specific antigen finds or selects particular cells capable of responding to it
Which is the second immunoglobulin to appear?
IgD
What is the least abundant immunoglobulin?
IgE
Which antibody is best at precipitation reactions?
IgG
Which antibody is known as the secondary response antibody?
IgG
What is the most common Immunoglobulin in total serum and half life?
IgG and a month
Which antibody is best at agglutination reactions?
IgM
Which antibody is best at triggering the classical pathway?
IgM
Which antibody is known as the macroglobulin?
IgM
Which antibody is known as the primary response antibody?
IgM
Which antibody is the potent defense against bacterial infections?
IgM
How is IgM similar to IgA?
IgM has a J chain and can occasionally acquire a secretory component allowing it to traverse epithelial cells and patrol mucous membranes
Where do antigens bind to an antibody
In the FAB variable region of the heavy and light chain
What are Bence Jones proteins?
L chain Proteins secreted in urine in Multiple Myeloma patients
