Antibodies are specialized proteins produced by the immune system to identify and neutralize harmful pathogens such as bacteria and viruses. Each antibody recognizes a specific antigen a unique marker on the surface of the pathogen and binds to it, preventing the invader from infecting cells or marking it for destruction by other immune cells. This targeted defense helps the body fight infections effectively and also contributes to long-term immunity by remembering pathogens for faster responses in the future.