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Definition

noun, plural: avidities

The combined strength of bond affinities in a complex.

Usage

The term may be used in chemistry to describe the dissociation-dependent strength of an acid or base. In proteins, avidity describes the binding intensity of multiple bond interactions between proteins. In immunology, avidity refers to the strength of antibody-antigen binding.

Avidity is different from affinity, which is a term used to describe the strength of a single bond. For instance, IgM may have low affinity but it has high avidity due to its 10 weak binding sites contrary to the two strong binding sites of IgG.

Miscellaneous

Compare: affinity See also: antibody-antigen complex, protein