Antigeenantikeha

Antigeenantikeha refers to the interaction between antigens and antibodies, a fundamental process in the adaptive immune system. Antigens are substances, typically foreign proteins or polysaccharides, that can trigger an immune response. Antibodies, also known as immunoglobulins, are Y-shaped proteins produced by B cells (a type of white blood cell) that are specifically designed to recognize and bind to particular antigens.

When an antigen enters the body, the immune system identifies it as foreign. B cells that recognize this specific antigen are activated and differentiate into plasma cells, which then secrete large quantities of antibodies. These antibodies circulate in the blood and lymph. The binding of an antibody to its corresponding antigen is highly specific, akin to a lock and key mechanism.

This antigen-antibody complex can neutralize the antigen directly, for example, by blocking a virus from entering a host cell. Alternatively, the complex can mark the antigen for destruction by other immune cells, such as phagocytes, or activate the complement system, a cascade of proteins that can lyse (burst) pathogens or mark them for clearance. The antigen-antibody reaction is the basis for many diagnostic tests, such as ELISA (enzyme-linked immunosorbent assay) and Western blotting, which are used to detect the presence of specific antigens or antibodies, indicating infection or immune status.