Antigen-Antibody Complex

Antigen-Antibody Complex designates the non-covalent molecular assembly formed when antibodies bind their cognate antigens through complementarity-determining region interactions with epitopes, forming the basis of immune recognition, diagnostic assays, and therapeutic mechanisms. These immune complexes can trigger downstream biological responses including complement activation, phagocytosis, or immune modulation.

The biopharmaceutical industry considers antigen-antibody complex formation across therapeutic development, diagnostics, and immunogenicity assessment. Therapeutic antibody mechanisms depend on forming stable complexes with target antigens blocking function, recruiting immune effectors, or clearing pathogens. Diagnostic immunoassays quantify analytes through complex formation signals. Immune complex-mediated adverse effects require monitoring during clinical development. Anti-drug antibody formation creates drug-antibody complexes potentially altering pharmacokinetics. Biophysical characterisation including surface plasmon resonance measures complex kinetics and thermodynamics providing detailed binding characterisation.