Equivalence zone
Definition
The range of antigen-to-antibody ratios at which binding sites on both molecules are maximally cross-linked, producing the largest lattice and the heaviest precipitate. Deviation in either direction yields smaller, soluble complexes and reduced or absent precipitation.
Related terms
- Double immunodiffusion (Ouchterlony)
- A gel diffusion method in which both antigen and antibody diffuse toward each other from separate wells in agar. Precipitin bands form...
- Immunoelectrophoresis
- A two-step technique: proteins are first separated by electrophoresis in agar gel, then antiserum diffuses from a parallel trough and forms precipitin...
- Lattice theory
- The structural explanation for precipitation proposed by Marrack in 1934. Multivalent antigens and bivalent antibodies can each bind more than one partner,...
- Precipitin
- An antibody that forms a visible precipitate when it reacts with its specific soluble antigen. The term is used interchangeably with precipitating...
- Ring precipitation test
- A technique in which antiserum is placed in a narrow capillary tube and antigen solution is layered carefully on top. A ring...
Explained in
- Precipitation Reactions: Principles and ApplicationsThe range of antigen-to-antibody ratios at which binding sites on both molecules are maximally cross-linked, producing the largest lattice and the heaviest pre...