Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
36 Cards in this Set
- Front
- Back
|
What does it mean for an antigen to be "multi-determinant?" |
The antigen has multiple epitopes, each recognized by a unique antibody Fab segment |
|
|
Is binding of an antibody to its antigen reversible or irreversible? |
Reversible |
|
|
Is antibody response to antigen homogeneous or heterogeneous? |
Heterogeneous |
|
|
Polyclonal antibodies (Definition) |
Unique antibodies that recognize unique epitopes on a multi-determinant antigen |
|
|
Monoclonal antibodies (Definition) |
Antibodies produced by clones of a single B cell; have same specificity |
|
|
What are some advantages of polyclonal antibodies? |
Beneficial in vivo - broader coverage and less affected by microbe mutation |
|
|
What are some advantages of monoclonal antibodies? |
Beneficial diagnostically - more specificity and less crossreactivity |
|
|
Affinity (Definition) |
Strength of binding between a single antibody binding site and a single antigenic determinant (epitope) |
|
|
Avidity (Definition) |
Strength of binding of an entire antibody molecule to a multi-determinant antigen |
|
|
How do monovalent and multivalent antigens differ in terms of reversibility of binding to antibody? |
Once a monovalent antigen dissociates from its antibody, it is unlikely to associate with the antibody again (functionally reversible)
The association between a multivalent antigen and its antibodies is functionally irreversible |
|
|
Binding of antibody to soluble multi-determinant antigens often leads to precipitation (in vivo or in vitro?) |
In vitro |
|
|
What is the endpoint for several diagnostic tests that utilize multi-determinant antigens? |
Visible precipitation |
|
|
What causes precipitation of multi-determinant antigens and antibodies? |
Crosslinking (due to bivalency of Ab) |
|
|
What is the relationship between [antigen] and the amount of antibody precipitation? |
↑ [antigen] = ↑ amount of antibody precipitation
UNTIL [antigen] = [antibody] |
|
|
When does antibody precipitation reach its peak? |
When [antigen] = [antibody] (equivalence) |
|
|
What happens to the amount of antibody precipitation as [antigen] exceeds [antibody]? |
The amount of antibody precipitation decreases, because the insoluble immune complexes become soluble |
|
|
How does slight antigen excess result in disease? |
Slight antigen excess promotes soluble immune complexes, which deposit in renal glomeruli, joints, and and small blood vessel walls; these deposited immune complexes activate the classical complement cascade, resulting in acute inflammation and tissue injury |
|
|
What are immunodiffusion assays? |
Diagnostic assays that detect precipitation of Ab:Ag complexes in a gel |
|
|
In a radial diffusion assay, what molecule diffuses (Ag or Ab)? |
Ag |
|
|
In a radial diffusion assay, what is the relationship between circle diameter and [Ag]? |
↑ diameter = ↑ [Ag] |
|
|
How does a double diffusion assay differ from a radial diffusion assay? |
Both Ag and Ab diffuse |
|
|
In immunoelectrophoresis, which serum components migrate toward the negative electrode? |
Albumin and α globulins |
|
|
In immunoelectrophoresis, which serum components migrate toward the positive electrode? |
β and γ globulins |
|
|
In immunoelectrophoresis, what is placed in the center trough of the gel and allowed to diffuse toward the separated serum components? |
Rabit anti-human serum |
|
|
Agammaglobulinemia (Definition) |
A genetic defect in B cell development that results in zero antibody production |
|
|
What type of tumor is a myeloma? |
B cell tumor |
|
|
What diagnostic tags are used in diagnostic assays that do not utilize Ab:Ag precipitation? |
Fluorochrome
Enzyme
Radionuclide
E⁻-dense |
|
|
What diagnostic tag is used in an ELISA assay? |
Enzyme-linked antibodies (may or may not be anti-human Ig) |
|
|
What is the endpoint of an ELISA assay? |
Color change |
|
|
An ELISA can be used ____ or ____ |
Diagnostically or quantitatively |
|
|
What diagnostic tags are used in immunohistochemistry (IHC)? |
Enzyme-linked antibodies or fluorophore-linked antibodies |
|
|
What is the follow up test for HIV after a positive ELISA? |
Western blot (immunoblot) |
|
|
What is the diagnostic tag used for a western blot (immunoblot)? |
Enzyme-linked anti-human Ig |
|
|
What is the diagnotic tag used in flow cytometry? |
Fluorophore-linked antibodies |
|
|
What is flow cytometry used to do? |
Rapidly quantify immune cells in blood |
|
|
How are monoclonal antibodies produced? |
1) Fuse B cells from mice immunized with antigen (e.g. p24) with myeloma cells
2) Grow cells in drug-containing medium that allows only hybrid cells (hybridomas) to survive
3) Place single hybridoma cells in individual wells and allow them to multiply
4) Select for antigen-specific hybridoma by introducing antigen (p24) to each well
5) Isolate desired hybridoma cells, which produce that desired Ab |
