An isotype usually refers to any related proteins/genes from a particular gene family

Gene family

A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions...

. In immunology

Immunology

Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. It deals with the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders ; the...

, the "immunoglobulin isotype" refers to the genetic variations or differences in the constant regions of the heavy and light chains. In humans, there are nine heavy chain isotypes and two light chain isotypes:

• heavy chain
  Heavy chain
  ]The immunoglobulin heavy chain is the large polypeptide subunit of an antibody .A typical antibody is composed of two immunoglobulin heavy chains and two Ig light chains. Several different types of heavy chain exist that define the class or isotype of an antibody. These heavy chain types vary...
  
  
  • α - IgA
    IGA
    Iga or IGA may stand for:-Given name:* a female given name of Polish origin. The name originates from the female given name Jadwiga and stands for gia,or gina in the USA....
    
     1, 2
  • δ - IgD
    IGD
    IGD can refer to:*Internet Gateway Device as defined in UPnP.*İGD, İlerici Gençler Derneği, Progressive Young Association of Turkey*Immunoglobulin D, an antibody protein involved in the maturation of B cells....
    
    
  • γ - IgG 1, 2, 3, 4
  • ε - IgE
    IGE
    IGE was one of the largest services company buying and selling virtual currencies and accounts for MMORPG. During its peak time, it had offices in Los Angeles, China , and headquarters & customer service centre in Hong Kong. IGE was one of the main monopoly in virtual economy services, also known...
    
    
  • μ - IgM
    IGM
    IGM as an acronym or abbreviation can refer to:* Immunoglobulin M , the primary antibody against A and B antigens on red blood cells* International Grandmaster, a chess ranking* intergalactic medium* Intragroup medium - see: Intracluster medium...
    
    
• light chain
  Light chain
  A light chain is the small polypeptide subunit of a protein complex.More specifically, it can refer to:* Immunoglobulin light chain* Ferritin light chain* Myosin light chain* Kinesin light chain* Dynein light chainLight chain may also refer to:...
  
  
  • κ
  • λ

Immunoglobulin class switching

Immunoglobulin class switching

Immunoglobulin class switching is a biological mechanism that changes a B cell's production of antibody from one class to another, for example, from an isotype called IgM to an isotype called IgG...

 can be used to change the class of the heavy chain, but not of the light chain.

Isotypes are distinct forms of light or heavy chains which are present in all members of
a species, encoded at distinct genetic loci. Kappa and lambda are isotypes of light chains.
Delta (δ), gamma:1 (δ1), etc are isotypes of heavy chains. All isotypes can be
readily found in all normal sera.

External links

• Overview at University of South Carolina School of Medicine
• Overview at Southern Illinois University Carbondale
  Southern Illinois University Carbondale
  Southern Illinois University Carbondale is a public research university located in Carbondale, Illinois, United States. Founded in 1869, SIUC is the flagship campus of the Southern Illinois University system...