Index >>Immunity >> Immunoglobulins

The globulins can be separated by electrophoresis into five components: α ,β, γ,µ and E-globulins and fibrinogen. The γ (gamma) globulins are also called immunoglobulins. They are serum proteins which function as antibodies against invading foreign material. The term immunoglobulin is now used generally to refer to all antibodies. Five classes of immunoglobulins have been recognized: IgG, IgA, JgM, JgD and IgE. The basic unit of immunoglobulins is a four-peptide structure consisting of two light chains (L) and two heavy chains (H).

The lambda chains can be similarly sub typed into five groups λ I, λ II, λ III, λ IV and λ V. The heavy chains are specific for each class of immunoglobulins. Gamma (Y) chains are found in IgG. alpha (α) chains in IgA, ­mu(µ) chains in IBM, delta (8) chains in IgD and epsilon,(E) cl1ains in IgE. On the basis of the first 18-20 amino acid residues the heavy chains fall into four subtypes, VIII, VHII, VRIII, and VHIV. However, It contrast to the light chains, the subtypes of the heavy chains are apparently shared by all the classes and subclasses.