Antibody Structure and Function Flashcards
immune response
stimulation of lymphocytes to divide and produce plasma cells that secrete polyclonal antibodies that bind to the immunogen
T/F: Fab has only a heavy chain, Fc has both light and heavy chains
False: Fab= anitgen binding, both light and heavy chains/ Fc= receptor binding, only heavy chain
What are the five different types of heavy chains
α (alpha) γ (gamma) δ (delta) ε (epsilon) μ (mu)
What are the two different types of light chains
λ (lambda) κ (kappa)
What are the five isotypes of immunoglobulins
IgG, IgA, IgM, IgE, IgD
What is the predominant immunoglobulin in blood/lymph, what is the percentage
IgG (15%)
Which immunoglobulin is used for passive immunization by transfer of antibodies
IgG
What are the functions of IgG
Agglutination, Opsonization, Fc reigon stimulates NK cells in cell mediated cytotoxicity, Fc reigon activates complement proteins (lysing bacteria), neutralize certain toxins (teatnus, botulinus, snake venom), crosses placenta
Which immunglobulin is pentameric, how many epitopes can it bind
IgM,5
What are the functions of IgM
Agglutination- quite effeicent due to polyvalency aiding in agglutination, isohemagglutinins- responsible for ABO blood types, activates complement
How long does the primary response take
10 days
How long does the secondary response take
3 days
Which of the two responses has a stronger and faster response, which antibody is made more in the stronger response
Secondary response, IgG
Which antibody is mostly in secretions, mucous membranes
IgA
T/F: IgA has a monomeric serum form that has two alpha H chains with no known biological function
True
What are the functions of IgA
Main defense against local infections, does NOT activate compliment, efficient in agglutination (good against viruses)
Which immunoglobulins are monomeric
IgG,IgD,IgE
What are the functions of IgD
No known functions
T/F: IgE is co-expressed with IgM
False: IgD
What is the function of IgE
causes the allergic reaction, high affinity to mast cells and basophils, crosslinking stimulates histamine release and prostaglandins while mediating inflammation
T/F: The heavy and light chains are composed of variable and constant reigons
True
The variable light chain (Vl) for Kappa is coded by which gene segments, how many of each gene is there and what are the total possible combinations
V and J, 40 for V and 5 for J, 200
The variable light chain (Vl) for Lambda is coded by which gene segments, how many of each is there and what are the total possible combinations
V and J, 40 for V and 4 for J, 160
What are the segments that code for the CDR in the heavy chain
D and J
Antigen-Driven Affinity Maturation
antigen stimulation causes clonal expansion and triggers processes that change CDRs of stimulated B-cells, enlarge antibody variety.specificity and B cell response
How are IgM and IgD produced together
alternative splicing
immunoglobulin class switching (isotype switching)
the constant-reigon portion of the antibody heavy chain is changed but the variable reason stays the same, does not affect antigen specificity but interacts with different effectors
S region
switch sequence in immunoglobulin class switching
T/F: S reigon is only in light chains
False: S reigon is only in heavy chains
In isotype switching what is the first step
An antigen is taken up by a B cell and processed
Which MHC class molecule presents a processed antigen to helper T cells
MHC Class II
What are the original antibodies made and what are the antibodies produced when production is switched
IgM and IgD, IgG and IgA, and IgE
IgG1 function
most abundant, respons to protein antigens
IgG2 function
bacterial capsular polysaccharide
IgG3 function
activator of pro-inflammatory responses by triggering the classical complement pathway
IgG4 function
is the least abundant, often generated following repeated exposure to the same antigen or persistent infections
