What is the role of antibodies in the immune system?

Antibodies play a crucial role in the immune system by identifying and neutralizing foreign substances, such as bacteria and viruses. They are specialized proteins produced by B cells in response to an infection or foreign antigen. When an antibody recognizes a specific pathogen, it binds to it, marking it for destruction by other immune cells. This binding can neutralize the pathogen directly, preventing it from entering or damaging host cells, or it can facilitate the process of opsonization, where the pathogen is tagged for elimination by phagocytic cells.

The significance of their role lies in the immune system's ability to adapt and remember previous encounters with pathogens. This antigen-antibody interaction is fundamental to the immune response, ensuring that the body can mount a rapid and effective defense against previously encountered invaders, which is also the basis for how vaccinations work.

In contrast, antibodies do not block the spread of cancer cells, produce hormones, or transport oxygen, as those functions are carried out by other components of the body, such as tumor suppressor genes in cancer control, endocrine glands for hormone production, and hemoglobin in red blood cells for oxygen transport.