Antibody promiscuity: Understanding the paradigm shift in antigen recognition

Area of Science:

• Immunology
• Structural Biology
• Biochemistry

Background:

• Affinity maturation typically reduces antibody paratope malleability for high-specificity antigen binding.
• Mature antibodies paradoxically exhibit promiscuity, binding multiple antigens despite a rigid binding pocket, challenging established specificity paradigms.

Purpose of the Study:

• To dissect the mechanisms underlying versatile binding in mature antibodies.
• To explore how antibodies achieve polyspecificity and degenerate specificity.

Main Methods:

• Review of existing literature on antibody structure-function relationships.
• Analysis of paratope structural rearrangements and antigen interaction plasticity.
• Consideration of antigen structural invariance across species.

Main Results:

• Polyspecificity is achieved through minimal paratope structural changes and flexible antigen interactions.
• Antigen structural invariance can influence mature antibody specificity.
• Germline antibodies exhibit polyreactivity, amplified by genetic recombination and structural/functional interactions.

Conclusions:

• Degenerate specificity in antigen recognition reduces the need for a vast array of antibodies.
• Antibody versatility is a key feature of the immune system, balancing specificity with broad recognition capabilities.