Polyclonal antibodies are defined as groups of antibodies that bind to which site on an antigen?

• A. Different antigens
• B. Monoclonal clones
• C. Different sites on different antigens
• D. Different sites on the same antigen

Answer: (D)

Polyclonal antibodies are a mixed population produced by many B-cell clones, and each clone makes antibodies against a different epitope on the same antigen. Because of this diversity, the antibody pool can bind to multiple sites on that single antigen, enhancing overall recognition. Monoclonal antibodies, by contrast, come from a single B-cell clone and target a single epitope. They don’t inherently cover multiple sites on the same antigen, and they aren’t defined by binding to different sites on different antigens.