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

The primary function of antibodies in the immune system is to mark pathogens for destruction. When antibodies bind to specific antigens present on pathogens such as bacteria and viruses, they create an immune complex that signals other components of the immune system to recognize and eliminate the bound pathogens. This marking process enhances the efficiency with which immune cells, such as phagocytes, can identify and destroy the invaders.

Antibodies can also neutralize toxins and inhibit the ability of pathogens to infect host cells, but their foundational role is in targeting pathogens for removal. By attaching to these harmful entities, antibodies facilitate opsonization—making pathogens more recognizable to immune cells—and activating other components of the immune response, including the complement system. Thus, the ability of antibodies to label pathogens is a critical step in the overall immune response and in maintaining health.