Antigen
Antibody
Binding
As mentioned previously, each antigen monomer has two identical antigen combining sites. Each site is formed by the V regions of a light and a heavy chain. This permits an antibody molecule to link two similar antigens together. Combination of several antibody and antigen units results in the formation of a lattice. Some small antigens contain different antigenic sites. Each type of site binds to a specific antibody molecule. Thus the lattice is formed through combination with different antibodies.The cell surface of microorganisms and large antigens usually contain several antigenically active sites. Several antibody molecules may link the antigenic sites to form aggregates, which can then be engulfed and destroyed by macrophages.
