Structure of Antibodies

Structure of Antibodies

• Basic Components:

  • Antibodies, also known as immunoglobulins (Ig), are glycoproteins produced by B-cells.

  • They consist of four polypeptide chains: two heavy chains and two light chains.

• Chains and Domains:

  • Each chain contains immunoglobulin domains, which are structural units that contribute to the antibody's stability and functionality.

  • The structure can be divided into:

  • Variable Region:

    • The tips of the Y-shaped molecule, consisting of both heavy and light chains.

    • This region is responsible for antigen binding and is unique to each antibody, allowing it to recognize specific targets (antigens).

  • Constant Region:

    • The stem of the Y shape comprises the constant region, which is uniform across antibodies of the same class.

    • This region interacts with other molecules of the immune system, aiding in immune response.

• Classes of Antibodies:

  • There are five main classes of antibodies:

  • IgG

  • IgA

  • IgM

  • IgE

  • IgD

• Hinges and Functional Domains:

  • Antibodies possess a hinge region between the Fab (fragment antigen-binding) and Fc (fragment crystallizable) regions, allowing flexibility to improve the fit with antigens.