Antibodies have three main functions:
1) Antibodies are secreted into the blood and mucosa, where they bind to and inactivate foreign substances such as pathogens and toxins (neutralization).
2) Antibodies activate the complement system to destroy bacterial cells by lysis (punching holes in the cell wall).
3) Antibodies facilitate phagocytosis of foreign substances by phagocytic cells (opsonization).
Antibodies and the four key features of the immune system
1. Specificity of antibodies: Antibodies precisely recognize toxins and pathogens.
2. Diversity of antibodies: Antibodies against a variety of antigens preexist in the body.
3. Immunological memory: We don’t don’t develop symptoms of measles
4. Immune tolerance: Self cells and tissues are not normally attacked.