ANATOMY

Detailed explanation-1: -Alternatively, antibodies binding to the surface of a pathogen can activate the proteins of the complement system, which was described in Chapter 2. Complement activation results in complement proteins being bound to the pathogen surface, and these opsonize the pathogen by binding complement receptors on phagocytes.

Detailed explanation-2: -Each antibody has a unique binding site shape which locks onto the specific shape of the antigen. The antibodies destroy the antigen (pathogen) which is then engulfed and digested by macrophages.

Detailed explanation-3: -Macrophages express all classes of Fc receptors, and they have immense potential to destroy tumors via the process of antibody-dependent phagocytosis. A number of studies have demonstrated that macrophage phagocytosis is a major mechanism of action of many antibodies approved to treat cancer.

Detailed explanation-4: -Pathogens have molecules called antigens on their surface. Antigens provide a unique signature for the pathogen that enables immune system cells to recognize different pathogens and distinguish pathogens from the body’s own cells and tissues.