Antigénként

Antigénként is a term used in immunology to describe a substance that can elicit an immune response. More specifically, it is a molecule or a part of a molecule that is recognized by the immune system, particularly by lymphocytes. When the immune system encounters an antigen, it can trigger a variety of responses, including the production of antibodies, the activation of T cells, and the development of immunological memory.

Antigens can be foreign substances, such as those found on the surface of bacteria, viruses, or fungi, or they can be endogenous substances that the immune system mistakenly identifies as foreign. Examples of exogenous antigens include pollen, food particles, and components of infectious agents. Endogenous antigens can include altered self-cells, such as cancer cells, or self-proteins that have been modified by disease processes.

The ability of a substance to act as an antigen is determined by its immunogenicity, which is its capacity to induce an immune response. While all immunogens are antigens, not all antigens are immunogens. Small molecules, for instance, may be recognized by antibodies but may not be capable of inducing an immune response on their own. These are called haptens and require a carrier molecule to become immunogenic.

The immune system's recognition of antigens is crucial for defending the body against pathogens and for maintaining tissue homeostasis. Diagnostic tests often rely on the detection of specific antigens or the antibodies produced in response to them. Vaccines also work by introducing antigens into the body, prompting the immune system to develop a protective response without causing disease.