Term
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Ab/ag secondary interactions may result in :
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Definition
o A. precipitation (soluble ag)
o B. Aggluntination (particulate ag)
o C. activation of complement |
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Term
What is needed in order for ab:ag interaction to precipitate, agglutinate, or activate complement? |
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Definition
· Cross linking of Ag by Ab is required for any of the three processes
· Ag must be multivalent and ab must be at least divalent
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Term
Name the three binding forces of ab:ag interaction |
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Definition
· Binding forces are relatively weak no covalent bonds (requires entities to be in close proximity to each other to get sufficiently strong binding)
o Electrostatic forces
o Van der waals forces
o Hydrophobic forces
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Term
What is Affinity in primary interaction |
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Definition
| the intrinsic association constant that characterizes the binding of an antibody with an epitope or hapten is called affinity |
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Term
what is avidity in primary interation |
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Definition
| used to denote the overall binding energy between antibodies and a multivalent antigen |
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Term
| Rxn between ab and a multivalent antigen that is particulate (in soluble particle) results in... |
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Definition
will cause cross-linking and eventually clumping |
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Term
· The agglutination assay is often used to measure ...
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Definition
| the level of Ab specific for a certain Ag |
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Term
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Why is agglutination assay only semi-quantitative ?
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Definition
| it does not measure the Ab concentration (W/V) |
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Term
High dilutions of serum in agglutinating assays do not usually cause agglutinaton because....?
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Definition
| as there is not enough antibodies to cause visible agglutinitatin |
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Term
| The highest dilution where aggluntination occurs in tha agglutination assay is called? |
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Definition
· The highest dilution which does cause it is called the titer
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Term
| In agglutination assy the tubes with high concentrations of serum where agglutination does not occur represent prozone what does that mean? |
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Definition
If there is an excess of ab present agglutination may not take place. This is bc every epitope is bonded at ab leaving no room for cross linking.
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Term
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Definition
· Due to the possible electrical charges on Ag surfaces ( such as on the surface of Rbc’s) when in saline suspension, an electrical potential is created.
· These molecules with similar charges will not be able to come very close to each other unless this is overcome
-agglutination may not occur
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Term
Which is the only Ig resistant to zeta potential? |
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Definition
IgM bc of the long FAB regions |
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Term
How does Direct coombs work |
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Definition
· Direct coombs: add antihuman ab to red cells suspected of having Ab bound to them, these abs will bond to the abs on the red cells an agglutination will occur
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Term
How does indirect Coombs work |
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Definition
· Indirect Coombs: the antihuman serum is added only after mothers serum is combined with Rh+ Rbcs (direct coombs measures bound Ab indirect measure serum Ab)
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Term
Agglutination can take place with soluble (non particle) antigens provided the Ag can be attached to an insoluble particle What is this called? |
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Definition
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Term
What happends in precipitation reactions |
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Definition
· Takes place when soluble Ag is mixed with abs
o these occur bc divalent Ab’s cross link with multivalent Ags to form a lattice
o the lattice grows an at a certain size, the Ag/Ab complex loses its solubility and precipitates out of solution
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Term
how does precipitate in gel work |
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Definition
· Semisolid media can be used as well as a solution (agar gels)
o soluble Ag and Ab are placed in wells cut in the gel
o somewhere between the wells, the Ag’s and Ab’s will be present at proportions optimum for precipitate formation
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Term
What is done in the k western blot test |
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Definition
§ Ag is separated in a gel the separated. Ag is then transferred onto a protein binding sheet
§ Labeled Ab is then put onto the sheet and binds with Ab
§ This technique Is widely used in research in HIV detection
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