Avidity

Definition

Avidity refers to the overall strength of binding between an antibody and its antigen, involving multiple binding sites. It is a cumulative measure that takes into account both the affinity of each individual interaction and the valency of the antibody.

5 Must Know Facts For Your Next Test

1. Avidity is crucial for understanding the effectiveness of polyclonal antibodies, which can bind to multiple epitopes on an antigen.
2. High avidity antibodies are generally more effective in neutralizing pathogens due to stronger and more stable interactions.
3. Avidity is different from affinity; while affinity describes the strength of a single antigen-antibody interaction, avidity encompasses all interactions collectively.
4. ELISA assays can be modified to measure avidity by introducing conditions that separate low-avidity interactions, such as chaotropic agents.
5. In monoclonal antibody production, achieving high avidity may require engineering antibodies with multiple binding sites or optimizing their spatial arrangement.

Review Questions

• What distinguishes avidity from affinity in terms of antibody-antigen interactions?
• Why is high avidity important for the effectiveness of polyclonal antibodies?
• How can ELISA assays be adapted to measure antibody avidity?

Related terms

Affinity: The strength of a single binding interaction between an antibody and its specific epitope.

Epitope: The specific part of an antigen that is recognized and bound by an antibody.

Polyclonal Antibodies: Antibodies produced by different B cell clones in response to an antigen, targeting multiple epitopes.