Problem 12

Antigens, which can be elements of a disease or cancer cell, trigger specific defenses which is also known as adaptive immunity. An antigen serves as a "marker" for the presence of a disease in the body. When the immune system detects the marker, adaptive immune responses start aggressively searching for cells that contain the antigen, like viruses, bacterial cells, or even cells inside our own bodies that may be affected by the pathogen. Immunity to a virus happens when the body understands to eliminate that specific antigen.