7: Antibody Structure Flashcards
Antibody
a multimeric protein produced and secreted by B cells
Each B cells produces __ antibody
one
4 main antibody functions
- opsonization
- ADCC
- complement activation
- neutralization
When is antibody production detectable after initial exposure?
3-7 days
What is the basic structure of an antibody?
2 light chains and 2 heavy chains
What subunit of an antibody determines Ig class?
heavy chain
What does the Fc portion contain?
heavy chain constant region
What does the Fab portion contain?
antigen binding site
T/F: Antibodies can bind to two of the same epitopes
T
How are the two antibody chains bonded?
non-covalently
Affinity
the measure of the strength of the interaction with one epitope
Avidity
the overall strength of the collective interactions; measure of affinity and valency
Valency
number of binding sites
What Ig isotypes always starts a sequence?
IgM and IgD
Idiotypic differences
difference in binding pocket, changes binding properties
Isotypic differences
difference in heavy chain, changes chemical properties
What is the main function of IgE?
sensitization of mast cells
What is the main function of IgM?
activates complement system
What is the main function of IgG?
activates complement system, transports across placenta, diffusion into extravascular sites
What is the main function of IgA?
transport across epithelium
What Ig is most abundant in blood?
IgG
What Ig is most abundant on mucosal surfaces?
IgA
J chain
in B cells, linked with IgM pentamer and IgA dimer; used to transport dimeric IgA across epithelial barriers
