What is the main role of IgG antibodies in the immune response?

The primary role of IgG antibodies in the immune response revolves around their ability to bind to antigens and neutralize them. IgG antibodies are the most abundant type of antibody found in the bloodstream and extracellular fluid, representing a critical component of the adaptive immune response.

When an IgG antibody encounters its specific antigen, it binds to it, which can neutralize the pathogen directly (for example, by preventing a virus from entering cells). This binding can also enhance other immune responses, such as opsonization, where the antibody marks the pathogen for destruction by phagocytic cells. Additionally, IgG can activate the complement system, which leads to further opsonization and lysis of pathogens.

While other immunoglobulins and immune mechanisms play important roles in the immune response, the ability of IgG to specifically bind to and neutralize antigens is a key feature that underscores its functionality in the immune defense process. Thus, the focus on the neutralizing capacity of IgG antibodies explains why this is the correct answer in the context of their role in the immune response.