Immunoglobulins, structure and function

Carayannopoulos L, Capra JD. 1993. Immunoglobulins Structure and function. In Paul WE, Ed. Fundamental Immunology. 3rd Ed., Raven Press, New York. 

Antibodies are molecules secreted by terminally differentiated B cells (a type of lymphocyte) known as plasma cells. Nearly all rabbit primary antibodies and most mouse monoclonal antibodies are immunoglobulins (Igs). There are five classes of Igs that differ structurally and functionally. Immunoglobulin G (IgG) molecules are the major class of Igs in the blood, which are predominantly produced in the secondary immune response. 

Five classes of Humans have five different classes of antibody molecule which differ both in immunoglobulins structure and in function. These are called immunoglobulin A (IgA), IgD, IgE, IgG and IgM and each has its own type of heavy chain a, 8, e, y and x, respectively. Thus IgA molecules have two identical a heavy chains, IgD molecules have two identical 8 heavy chains, etc. The human IgG class of antibodies is further divided into four IgG subclasses IgG, IgG2, IgG3 and IgG4, having y, y2, y3 and y4 heavy chains respectively. 

Proteolytic dissection has contributed substantially to our knowledge of the structure and function of the y-globulins. The yG-immunoglobulins constitute the largest portion, about 80% or more, of the y-globulin system and have MW of about 160,000. The molecules are elongated, about 235 X 44 A. A major advance in understanding the structure and... 

Pumphrey RSH. Structure and function of immunoglobulin. In Ward AM, Whicher JT, editors. Immunochemistry in clinical laboratory medicine. Lancaster, UK MTP Press, 1979 85-98. 

The major antibody in the serum is IgG and as this is the best-understood antibody in terms of structure and function we shall consider it shortly. The other antibody classes will then be considered in relation to IgG. First, however, a very brief overview of the structure and function of the different immunoglobulins will be presented [1],... 

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