Precipitation and Agglutination Flashcards
Soluble antigens combine with soluble antibody to produce insoluble complexes that are visible
Precipitation
Particulate antigens combine with antibody to form larger complexes
Agglutination
initial attraction force between a single Fab site on an Ab molecule and a single epitope
Affinity
refers to Abs capable of reacting with Ags that are structurally to the original Ag that induced Ab production
Cross-reactivity
sum of all attractive forces or sum of the affinities of all individual Ab-Ag combining sites
Avidity
A measure of overall stability of an Ag-Ab complex
Avidity
Precipitation results from random, reversible reactions whereby each Ab binds to more than one Ag and vice versa, forming a stable network or lattice
Zone of Equivalence
IgM has the potential to bind ? different Ag
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Soluble antigen + soluble antibody = insoluble complex
Precipitation
Soluble antigen + soluble antibody
Insoluble complex
Insoluble particle + soluble antibody = insoluble complex that form visible aggregates
Agglutination
Soluble antigen + soluble antibody
Insoluble complex
Insoluble particle + soluble antibody
insoluble complex that form visible aggregates
oppositely charged particles
Ionic bonds
polar molecules
Hydrogen bonds
nonpolar molecules
Hydrophobic bonds
interaction between electron clouds of oscillating dipoles
Van der Waals forces
Lattice hypothesis by?
Marrack
Antigen combines with only one or two Ab molecules; and no cross-linkages are formed
Prozone Phenomenon
Every available Ab site is bound to a single Ag; and no cross-linkages are formed
Poszone Phenomenon
A light scatter technique that measures reduction in intensity of light produced by immune complexes in a solution
Turbidimetry
A light scatter technique that measures the amount of light scattered at a particular angle
Nephelometry
The greater the immune complexes?
The lesser the light transmitted and The greater the light scatter
A single immunodiffusion technique that the antigen diffuses out until the point of equivalence is reached
Radial Immunodiffusion (RID)
Ag is allowed to diffuse in completion until equivalence is reached (no further change in diameter) that occurs between 24-72 hours
End-point method (Mancini method)
Uses ring diameter readings taken at about 19 hours before equivalence is reached
Kinetic method (Fahey method)
A double immunodiffusion technique to determine if the antigens share identical epitopes and is still used to identify fungal antigens such as Aspergillus, Blastomyces, Coccidioides, and Candida
Ouchterlony double diffusion (ODD)
has an arc
Identity
has a spur
Partial Identity
has crossed lines
Nonidentity
A double immunodiffusion technique that incorporates electrophoresis to enhance results
Immunoelectrophoresis (IEP)
Replaced IEP
Immunofixation electrophoresis
(1) Electrophoresis of serum (or urine), i.e., a source of Ag. Antiserum is placed in the trough and then incubated at 18-24 hours.
(2) Immunodiffusion occurs and precipitin line develops.
Immunoelectrophoresis
(1) Electrophoresis of serum (or urine), i.e., a source of Ag.
(2) Antiserum is placed directly at the gel’s surface and then incubated for 30 mins, washed, and will be stained.
Immunofixation electrophoresis (IFE)
A single-dimension electroimmunodiffusion and is an adaptation of RID
Rocket Immunoelectrophoresis (RIE)
A single-dimension double electroimmunodiffusion and is a rapid version of ODD
Counterimmunoelectrophoresis (CIE/CIEP)
initial binding, depends on the nature of antibody and the antigen-bearing surface. This is a reversible reaction
Sensitization
governed by factors such as pH, ionic strength, and temperature
Lattice Formation
Occurs when Ags are found naturally on a particle and Agglutination indicates the presence of patient antibodies (Widal test, ABO blood typing)
Direct Agglutination
Particle coated Ag are NOT normally found on their surface (erythrocytes, latex, and gelatin) and Agglutination indicates the presence of patient antibodies (RF, Ab to Group A Streptococcus Ag, and Ab to viruses such as rotavirus, cytomegalovirus, rubella, and VZ)
Indirect/Passive Agglutination
Ab rather than Ag is attached to a carrier particle and Agglutination indicates the presence of patient antigens (Rapid ID of Ag from infectious agents and detecting soluble Ag in urine, spinal fluid, and serum)
Reverse Passive Agglutination
The use of synthetic beads or particles provides advantages of consistency and uniformity
Indirect/Passive Agglutination
Particle coated Ag are NOT normally found on their surface
Reverse Passive Agglutination
Particles compete with patient Ag for a limited number of Ab sites
Inhibition Agglutination
Detection of illicit drugs such as cocaine or heroine
Inhibition Agglutination
Lack of agglutination is a (+) reaction in Inhibition Agglutination indicates?
Presence of patient antigens
Lack of agglutination is a (+) reaction in Hemagglutination Inhibition indicates?
Presence of patient antibodies
RBCs are the indicator particles (Ab to certain viruses (rubella, influenza, RSV)
Hemagglutination Inhibition
