Immunology and Serology (DVT2153) · YOUR LOGO Antigen-Antibody Interactions The binding of...
Transcript of Immunology and Serology (DVT2153) · YOUR LOGO Antigen-Antibody Interactions The binding of...
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Immunology and Serology (DVT2153)
Antigen-Antibody Interactions (Lecture)_Week VI Lecture
By: Dr. Erkihun Aklilu
12 March 2012
Universiti Malaysia KelantanFaculty oF veterinary medicine
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Antigen-Antibody Interactions
The binding of antibody to antigen is a reversibleprocess, involving non-covalent bonds
The specific association of antigens and antibodiesis dependent on:
Hydrogenbonds
hydrophobic interactions,
electrostatic forces, and
van der Waals forces.
It is a reversible reaction
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Antigen-Antibody Interactions
The law of mass actionAt the beginning, a chemical reaction proceeds
predominantly in one direction, but the reverse rateprogressively increases until the forward and reverse speedsare equal. At this point, the reaction is said to have reachedits equilibrium.
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Antigen-Antibody Interactions
FIGURE- Precipitation reactions in fluids yield a precipitin curve.
( Lattices or large aggregates )
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Antigen-Antibody Interactions
Antigen-Antibody Interaction involves various non-covalent interactions between the epitope of theantigen & the variable-region (VH/VL) domain of theantibody molecule.
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Antigen-Antibody Interactions
Terminologies
Affinity: Is the strength of the reaction betweena single antigenic determinant and a singlecombining site on the antibody.
Avidity: Is a measure of the overall strength ofbinding of an antigen with many antigenicdeterminants and multivalent antibodies.
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Antigen-Antibody Interactions
Specificity:-The ability of an individual antibodycombining site to react with only oneantigenic determinant
OR
-The ability of a population of antibodymolecules to react with only one antigen.
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Antigen-Antibody Interactions
Cross reactivity: the ability of an individualantibody combining site to react with morethan one antigenic determinant or the ability ofa population of antibody molecules to reactwith more than one antigen.
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Antigen-Antibody Interactions
Factors Affecting Antigen-AntibodyReactionsFactors acting on the equilibrium constant
- Temperature- pH- Ionic strength- Enzyme treatment of red cells
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Antigen-Antibody Interactions
Other factors
- Concentrations of antigen and antibody- Zygosity (number of antigen sites per cell)- Duration of incubationFactors affecting the antigen-antibody reaction.pdf