What are antibodies made of?

Antibodies consist of a total of four polypeptide chains. They are made out of two identical (L) chains containing approximately 220 amino acids, and two identical heavy (H) chains containing about 440 amino acids. The light and heavy chains are held together by both non covalent and covalent disulfide bonds. An antibody is made of two identical halves, each with the identical antigen-binding site. The two chains typically work together to form the antigen-binding surface. More specifically, the two antigen-binding sites are formed by the N-terminal region of the light chain and the N-terminal of a heavy chain. Both the Fc and hinge region are formed by two heavy chains.