Introduction to Therapeutic Antibodies

Abstract

Antibodies are immunoglobulins that are part of the humoral immune response and are secreted by the B-cells (plasma cells). Antibodies act by binding to either soluble antigens or ligands that are expressed on the surface of organisms or cells. In terms of structure, antibodies are Y-shaped glycoproteins made up of two heavy chain polypeptides and two light chain polypeptides that are held together by disulfide bridges. The light and the heavy chain are made up of constant regions and variable regions with light chain having one variable and one constant region and the heavy chain having one variable and three to four constant regions (part of which forms the Fc, crystallizable portion). The variable region of the light chain and the heavy chain together forms the antigenbinding site (Fab, antigen binding portion). At the end of each variable region is the hypervariable region (CDR, complementary determining region) and it is this region that allows for numerous conformations for infinite antibody-antigen binding probability.