European Journal of Molecular & Clinical Medicine

Abstract

Immunoglobulins are heterodimeric proteins made up of two heavy (H) and two light (L)
chains. They can functionally be divided into variable (V) domains that bind antigens and
constant (C) domains that determine effector functions, such as complement activation or Fc
receptor binding. The variable domains are produced by a complex series of events in gene
rearrangement and can then be subjected to somatic hypermutation after antigen exposure.
Each V domain can be divided into three regions of sequence variability, called CDRs, or
complementarity determining regions, and four regions called framework regions, or FRs, of
relatively constant sequence. The three CDRs of the heavy chain are combined with the three
CDRs of the light chain to procedure the antigen binding site. Five major groups of heavy
chain C domains exist. The isotypes of IgM, IgG, IgA, IgD, and IgE are defined by each class.
To activate altered effector function while preserving antigen specificity, the constant
domains of the heavy chain can be switched. The aim of this review is to review current
development in our understanding of the structure, function and therapeutic effects of
immunoglobulin, as well as the immunological implications of Ig for the management of
autoimmune diseases and cancer. For that reason, a literature search on PubMed and Google
Scholar was carried out using the specific keywords.