Final answer:
The protective mechanism of antibodies involves neutralizing antigens by coating them, preventing their attachment to host cells, and tagging them for destruction by phagocytes. These neutralized pathogens are then filtered by the spleen and eliminated from the body. Antibodies also activate other immune responses like the complement system and enhance phagocytosis.
Step-by-step explanation:
The protective mechanism mounted by the antibodies serves to disarm and/or immobilize the antigens until they can be disposed of by phagocytes before they can infect cells. Antibodies function by coating extracellular pathogens and neutralizing them, thereby blocking key sites that enhance their infectivity, such as receptors that facilitate the docking of pathogens on host cells. This process of neutralization prevents pathogens from entering and infecting host cells. The neutralized antibody-coated pathogens are then filtered by the spleen and can be eliminated in urine or feces.
Additionally, antibodies can bind to viruses or bacteria, creating bridges between antigenic particles, clumping them together and inhibiting their function. They help to activate the complement system, leading to the destruction of cells bearing the antigen. Moreover, the formation of antigen-antibody complexes stimulates phagocytosis, thereby enhancing the destruction of these pathogens by phagocytic cells such as macrophages, dendritic cells, and neutrophils.
The presence of antibodies also stimulates inflammation and their role extends to preventing pathogen attack by existing in mucus and on the skin as a barrier.