How do antigens differ from antibodies?

Antigens are substances that can provoke an immune response when detected by the body. These can be proteins, polysaccharides, or even nucleic acids from pathogens such as bacteria and viruses. When an antigen enters the body, it is recognized as foreign, which activates the immune system to defend against it.

In contrast, antibodies are proteins produced by B cells of the immune system in response to the presence of antigens. They play a crucial role by specifically binding to antigens, which can neutralize the threat posed by the pathogen and mark it for destruction by other components of the immune system. This binding can prevent the pathogen from infecting cells or can facilitate its elimination through various immune mechanisms.

Therefore, the distinction lies in their functions: antigens trigger the immune response, initiating the production of antibodies, while antibodies are the response itself, working to neutralize and eliminate the antigens and the pathogens they are associated with. Understanding this fundamental relationship is key in immunology and helps clarify how the immune system recognizes and responds to threats.