antígeni

Antígeni, also known as antigen, is a molecule that triggers an immune response in the body. Antigens are typically proteins or carbohydrates found on the surface of cells, viruses, bacteria, and other microorganisms. When the immune system encounters an antigen it does not recognize, it produces antibodies to neutralize and destroy the foreign substance. Antigens can also be used in medical tests to detect the presence of specific pathogens or diseases.

There are two main types of antigens: endogenous and exogenous. Endogenous antigens are produced by the body's own cells and are recognized as self by the immune system. Exogenous antigens are foreign substances that enter the body and are recognized as non-self. The immune system's response to exogenous antigens is what helps protect the body from infections and diseases.

Antigens can be further classified based on their size and structure. Small antigens, such as proteins and peptides, are typically recognized by the immune system's B cells, which produce antibodies. Larger antigens, such as those found on the surface of bacteria and viruses, are recognized by the immune system's T cells, which help coordinate the immune response and destroy infected cells.

Antigens are also used in various medical applications, including vaccines, diagnostic tests, and immunotherapy. Vaccines contain antigens from pathogens to stimulate the immune system and provide immunity against future infections. Diagnostic tests, such as ELISA and Western blot, use antigens to detect the presence of specific pathogens or diseases. Immunotherapy, such as cancer vaccines, uses antigens to stimulate the immune system and target cancer cells.

In summary, antigens are molecules that trigger an immune response in the body. They can be endogenous or exogenous, and can be classified based on their size and structure. Antigens are used in various medical applications, including vaccines, diagnostic tests, and immunotherapy. Understanding antigens is crucial for developing effective immune responses and treatments for various diseases.