What is the primary function of antibodies in the immune system?

Antibodies play a crucial role in the immune system by specifically recognizing and binding to foreign substances, known as antigens, such as toxins and pathogens (bacteria and viruses). This process is essential for acquiring immunity and helps to neutralize these harmful agents, making it easier for the immune system to eliminate them from the body.

When antibodies bind to an antigen, they can neutralize its harmful effects directly or mark it for destruction by other immune cells, such as phagocytes. This neutralization process is fundamental to the body’s defense against infections and diseases, hence highlighting the primary function of antibodies in maintaining immune health.

In contrast, while blood clotting is essential for preventing blood loss, its function is carried out by platelets and clotting factors rather than antibodies. Transporting nutrients is a role performed primarily by the circulatory system, specifically through blood plasma and red blood cells. Regulating body temperature is a function of the body's thermoregulatory mechanisms and does not involve antibodies. Therefore, the ability of antibodies to neutralize pathogens and toxins is a defining characteristic of their role in the immune response.