Vastaainetyyppejä

Vastaainetyyppejä refers to different classes or isotypes of antibodies, which are proteins produced by the immune system to identify and neutralize foreign substances such as bacteria and viruses. These different types are distinguished by their heavy chains, which determine their structure and function. In mammals, there are five main isotypes: IgG, IgM, IgA, IgD, and IgE.

Immunoglobulin G (IgG) is the most abundant antibody in serum and plays a crucial role in the secondary immune response. It is responsible for opsonization, complement activation, and antibody-dependent cell-mediated cytotoxicity. Immunoglobulin M (IgM) is typically the first antibody produced during an initial immune response. It is a large molecule that exists as a pentamer and is effective at activating the complement system.

Immunoglobulin A (IgA) is primarily found in mucosal secretions like saliva, tears, and breast milk, providing localized immunity. It exists as a monomer in serum and a dimer in secretions. Immunoglobulin D (IgD) is found on the surface of B cells and is thought to play a role in B cell activation. Immunoglobulin E (IgE) is involved in allergic reactions and defense against parasites. It binds to mast cells and basophils, triggering the release of inflammatory mediators. The specific function and distribution of each antibody type are critical for a robust and tailored immune response.