SI LEC - Classes of Antibodies Flashcards
Most abundant immunoglobin,
IgG
% IgG
75-80% of serum Ig
S and MW of IgG
7S, MW=150,000
Longest half life (23-25 days)
IgG
Half life of IgG
23-25 days
IgG which cross the placenta
IgG1, IgG3 and IgG4
IgG least efficient in crossing the placenta
IgG2
IgG most effective complement activator
IgG3:
IgG High affinity for FcR on phagocytic cells, good for opsonization
IgG1 and IgG3
FUNCTIONS Provide immunity to the newborn Fix complement Coating antigen (opsonization) Neutralizing toxins and viruses Participate in agglutination and precipitation
IgG
% IgM
5-10%
S and MW of IgM
19S, MW= 970,000
Shorter life span than IgG (about 10 days)
IgM
Pentameric version is secreted, Monomeric on B cell surface
IgM
IgM version in secretion
pentamer
IgM version in B cell surface
Monomer
5 monomeric units are held together by __ chains
J
More efficient than IgG in complement activation
IgM
Cannot cross the placenta
IgM
Antigen-induced conformational changes in IgM
(2)
starfish or planar
staple or crab
FUNCTIONS Complement fixation Opsonization Agglutination Toxin neutralization
IgM
*First Ig of primary immune response
IgM
IgG increased at what response (primary or secondary)
secondary
conc of IgM in primary and secondary response
SAME
Long lag phase
Slow exponential increase in antibody
Short lived response
Primary Immune Response
Anamnestic response
Short lag phase
Antibody increase is more rapid
Long lived response
Secondary Immune Response
% IgA in serum IgG
10-15% of serum IgG
S and MW of IgA
7S and MW=160 000
Predominant Ig in secretions
IgA
IgA Subclass found in serum, mainly monomeric, polymers possible not common though
IgA1
IgA Subclass found in secretions, as dimer, w/ J-chain, w/ secretory component
IgA2
IgA1 and IgA2: differ in __ aa (13 of which is located in the hinge region)
22
__ more resistant to bacterial proteinases than IgG1
IgA2
MW of IgA secretory component
70 000
IgA Structure
attached to Fc region around the hinge of the alpha chain,
Secretory component
IgA Structure
facilitates transport of IgA to mucosal surface,
Secretory component
IgA Structure
masks sites that would be susceptible to protease cleavage
Secretory component
not capable of C’ activation
IgA
FUNCTIONS of Ig
Patrol mucosal surfaces
Neutralize toxins
Helps prevent bacterial adherence to mucosa
IgA
extremely scarced in the serum (0.001%)
IgD
% IgD in serum
0.001%
half life of IgD
2-3 days
MW of IgD
MW=180,000
Expressed on B-cell Surface
- Play a role in B cell activation - Regulate B cell maturation and differentiation
IgD
Least abundant (0.0005%)
IgE
% IgE
0.0005%
S and MW of IgE
8S, MW=190,000
Heat labile
IgE
Nuisance ab
IgE
Not capable of C’ fixation, agglutination, opsonization, or crossing the placenta
IgE
Binds mast cells and basophils thru Fc(EPSILON)R (CH3)
IgE
Binding causes degranulation (Histamine release)
IgE
IgE Binds mast cells and basophils thru __
Fc(EPSILON)R (CH3)
H chain genes are located on chromosome __
14
kappa chain genes are on chromosome _
2
the lambda chain genes are on chromosome __
22
IgG with extra constant chain
IgG and IgM
extra constant chain of IgG
CH2
extra constant chain of IgM
CH3
extra constant chain of IgG are sites for __
complement binding
Ig implicated in HDN
IgG
agglutination, nature of Ag
INSOLUBLE
precipitation, nature of Ag
SOLUBLE
conformation of IgM when unbound to Ab
Starfish
conformation of IgM when bound to Ab
Crab
patrol Ab
IgA
protects IgA from enzymes that may degrade it
secretory component
with polyIg receptor
IgA
Ab diversity
different chromosomes control different parts of Ab
Tonegawa
theory
1.) the lock and key concept of the fit of ab for ag 2.) the idea that an ag selected cell w/ built-in capacity to respond to it.
Ehrlich’s Side Chain Theory
-individual lymphocytes are genetically pre-programmed to produce one type of Ig and that a specific antigen finds or selects those particular cells capable of responding to it, causing them to proliferate
Clonal Selection Theory
3 Gene groups of HC genes
VH, D, J
How many VH
39
How many D
23
How many J
6
