Immunoglobulinmolekulák

Immunoglobulinmolekulák, commonly known as antibodies, are Y-shaped proteins produced by plasma cells, a type of B lymphocyte. They are a crucial component of the adaptive immune system, playing a vital role in identifying and neutralizing foreign substances such as bacteria, viruses, and other pathogens. Each immunoglobulin molecule is composed of four polypeptide chains: two identical heavy chains and two identical light chains, linked together by disulfide bonds. The tips of the Y-shaped arms contain variable regions, which are unique in their amino acid sequence and are responsible for binding to specific antigens, the molecular targets on foreign invaders. The stem of the Y-shaped molecule, known as the constant region, interacts with other immune system components, such as complement proteins or immune cells, to facilitate the elimination of the antigen. There are five main classes of immunoglobulins: IgG, IgM, IgA, IgD, and IgE, each with distinct structures and functions that contribute to different aspects of the immune response. For example, IgG is the most abundant class and is important for long-term immunity, while IgM is the first antibody produced during an initial infection. IgA is found in secretions like tears and saliva, providing mucosal immunity, and IgE is involved in allergic reactions and defense against parasites.