Adaptive immunity Antibodies (complete) Flashcards
What is passive immunity
the passing of immunity (through Antibodies and B cells) from one person/organism to another
what does immunogenicity refer to
a molecules ability to induce an immune response
what does antigenicity refer to
the ability to react specifically with the products of an immune response
what is humoral immunity
immunity that is mediated by antibodies (macromolecules) and B-cells
how does foreigness correlate with immunogenicity
the more foreign, the more immunogenic
What are haptens
small molecules that illicit an immune response, only when paired to a large carrier, even if the carrier doesn’t illicit an immune response on its own
what is neutralization by antibodies
the binding of antibodies to viruses, bacteria and toxins and the consequential prevention of their attachment to host cells
What is avidity
the overall strength of association of a multivalent antibody and a multivalent antigen
what is affinity
The strength of association between 1 epitope/paratope only
which is a better measure of how antibodies act with antigens? avidity, or affinity?
avidity
Where do you find antibodies in circulation
in the y-globulin fraction of serum
Antibodies are glycoprotiens. T or F?
True
what are the basic parts of antibodies
2 identical heavy chains and 2 identical light chains
What types of bonds hold the heavy and light chains of antibodies together
disulfide bonds
both heavy and light chains have homologous domains that have disulfide riveted loops. how many domains do light chains have, and how many domains do heavy chains have
light chains have 2 domains
heavy chains have 5 domains
how many of the heavy chains 5 domains are variable
1
how many of the light chains 2 domains are variable
1
what are the singular variable domains of the heavy and lights chains used for
antigen binding
what are the constant domains of the heavy and light chains used for
biological activity
for each antibody, how many antigen binding sites do you have
2 (made by the variable domains of each pair of heavy and light chains)
Where do you find the hypervariable regions of antibodies
in the antigen binding pocket (on the variable domains)
which two classes of Antibodies are polymers
IgA and IgM
which two classes of Antibodies have J chains
IgA and IgM (the polymers)
which two classes of antibodies have an extra constant domain
IgM and IgE
which two classes of antibodies have subclasses
IgA and IgG
What are the main functions of IgM
neutralization
complement activation
antigen trapping
antigen receptor of Naive and some memory B-cells
What are the main functions of IgG
neutralization complement activation induction of phagocytosis ADCC transfer of adaptive immunity to offspring regulation of antibody production
what are the main functions of IgA
neutralization
protection of mucosa
induction of phagocytosis
protection of newborn mucosa via milk
what are the main functions of IgE
activation of mast cells and basophils to promote barrier immunity
what is the main function of IgD
antigen receptor on Naive follicular B cells
Which is the first antibody made, and has paratopes with lower affinity
IgM
what is the main class of antibodies in the blood and tissues
IgG
which antibody is involved in allergies
IgE
which antibody is found as a BCR (B-cell Receptor) and has no effector properties
IgD
how do polymeric IgA (and to a lesser extent polymeric IgM) get from the basal side of an epithelial cell to the lumen on the other side of the cell
they bind a polymeric Ig receptor on the basal side of the epithelial cell, this transports it through a vesicle and to the luminal side of the cell. Then proteases cleave the polymeric Ig receptor (most of it stays with the IgA) and the polymeric IgA is now in the lumen
what is the portion of the polymeric Ig receptor that is left with the polymeric IgA in the lumen called
the secretory component
what are the two main functions of the secretory component on the polymeric IgA (IgM) in the lumen
protect it from proteases
binds to mucus to localize the antibody
what does FcRn do to IgG (similar to what a polymeric Ig receptor does to polymetric IgA in epithelial cells)
it transports IgG across the placenta into the fetus
for newborns, what are the levels of antibodies
- high IgG
- low/medium IgM
- Low IgA
how does IgG activate complement
C1q of complement binds a cluster of IgG, this binding distorts C1q, which activates C1r and C1s (those cleave C4 and C2)
how does IgM activate complement
the same way as IgG EXCEPT that the C1q just binds to one IgM (polymer). this distorts C1q, activates C1s and C1r. those cleave C4 and C2
what is the function of Fc receptors
they bind the back side on antibodies (the opposite side of the antigen binding site)
on which types of cells do you find Fc receptors
macrophages neutrophils mast cells basophils eosinophils NK cells
what does binding of an antibody (attached to an antigen) to the Fc receptor of macrophages and neutrophils cause them to do
activate phagocytosis and respiratory burst
what does binding of an antibody (attached to an antigen) to the Fc receptor of mast cells, eosinophils, and basophils cause them to do
release their granules
what does binding of an antibody (attached to an antigen) to the Fc receptor of NK cells cause them to do
deliver perforin/granzyme hit (ADCC)
what is ADCC
antibody-dependent cellular cytotoxicity (the delivery of perforin/granzyme hit from NK cells that have binded antibodies to their Fc receptor)
how does streptococci prevent the usage of Fc cells
it makes IgA-binding proteins that block the ability of IgA to bind to the Fc receptors of phagocytes
how does staphylococcus aureus prevent the usage of Fc cells.
it makes a protein that binds to the Fc end of IgG and prevents IgG binding to Fc receptors of phagocytes
which types of IgG are neutralizing antibodies? and what does that mean
IgG2 and IgG4.
netralizing means that they don’t activate complement or bind to most Fc receptors, they just neutralize the pathogen
which types of IgG activate complement and bind to most Fc receptors (thus causing phagocytosis and inflammation)
IgG1 and IgG3
which types of IgG cause a Th1 response
IgG1 and IgG3
what are monoclonal antibodies for
they are antibodies that are made outside of the organism in which they are used as a means of treating a disease or infection
