Study Set Content:
visible aggregation of particles caused by combination with specific antibody
Agglutination
Particulate antigens with its specific antibody
Agglutination - Large
Soluble antigens by soluble antibodies forming insoluble complexes
Precipitation - Smaller
Abs that produce such reactions
Agglutinins
Agglutination of particles to which soluble antigen has been adsorbed is a serum
Precipitins
Two – Step Process of Agglutination
- Initial binding/Sensitization
- Lattice Formation/ Forming of Large Aggregates
involves Ag–Ab combination through single antigenic determinants on the particle and is rapid and reversible
Initial Binding/Sensitization
is the formation of cross-links that form the visible aggregates.
Lattice Formation/Formation of Large Aggregates
happens in a split of second, can be dissociated
Initial Binding/Sensitization
represents the stabilization of Ag–Ab complexes; Visible aggregation or precipitation
Lattice formation/Formation of Large Aggregates
Biological Carrier
Erythrocytes
Artificial Carrier
Latex Particles/ Colloidal Charcoal
Factors Affecting Ag-Ab Association (Sensitization)
- Particle Charge
- Electrolyte Concentration and viscosity
- Antibody type
- Antigen-to-antibody ratio
- Antigenic Determinants
- Physical Conditions (pH, Temperature, Duration of Incubation)
Inert particles such as latex, RBCs, and bacteria have a net negative surface charge called the
Zeta Potential
What is used to reduce the ionic strength of a reaction?
LISS (Low Ionic Strength Saline)
Inert particles such as latex, RBCs, and bacteria have a net negative surface charge called the zeta potential; By reducing the ionic strength of a reaction medium (e.g., using low ionic strength saline [LISS]), antibody uptake is enhanced
Particle Charge & Electrolyte Concentration & Viscosity
Determine the technique:
Removes negatively charged sialic acid residues from the cell surface membrane
Enzyme Pretreatment of RBCs
Increase electrical conductivity of environment
Addition of Colloids (e.g albumin)
Mechanical process to force red blood cells closer together
Centrifugation
represents the physical attachment of antibody molecules to antigens on the erythrocyte membrane.
Sensitization
