antigenos

Antigenos are molecules that can elicit an immune response. They are typically foreign substances, such as parts of bacteria, viruses, fungi, or other microorganisms, but can also include pollen, transplanted cells, or even abnormal cells from within the body, like cancer cells. The immune system recognizes these antigens as non-self and initiates a response to neutralize or eliminate them.

The immune system's recognition of antigens is a highly specific process. Immune cells, particularly lymphocytes like B cells and T cells, have receptors on their surface that can bind to specific parts of an antigen, known as epitopes. When an antigen binds to these receptors, it triggers a cascade of events leading to an immune response. For B cells, this often involves the production of antibodies, which are proteins that can bind to antigens and mark them for destruction or neutralize their harmful effects. T cells can directly kill infected cells or help regulate the immune response.

Antigens are crucial for the development of immunity. Vaccinations work by introducing weakened or inactivated forms of antigens, or fragments of them, into the body. This allows the immune system to develop a memory of the antigen without causing disease, so that a future encounter with the actual pathogen can be met with a rapid and effective immune response. The study of antigens and the immune response they provoke is fundamental to immunology and has led to significant advancements in medicine, including the development of vaccines and immunotherapies.