The session on antigen-antibody interactions will cover the basics of how antibodies recognize and bind to specific antigens, exploring the concepts of affinity and avidity. Clinical applications will be emphasized, particularly in diagnostics such as ELISA and agglutination tests. The discussion will also include the role of antigen-antibody interactions in vaccine development, understanding autoimmune diseases, diagnosing infections, immune disorders, and how these interactions are utilized to design tailored immunotherapies.