Somatic hypermutation

Somatic Hypermutation is a biological process that occurs in the immune system. This process is responsible for the diversification of antibodies, which are proteins that the immune system uses to fight off infections. Somatic hypermutation involves the mutation of the DNA that codes for these antibodies, leading to a variety of different antibody molecules.

Mechanism

The process of somatic hypermutation is initiated by an enzyme called activation-induced cytidine deaminase (AID). This enzyme deaminates cytosine bases in the DNA, converting them into uracil. The presence of uracil in the DNA then triggers a repair response, which can result in the introduction of mutations.

Role in Immunity

Somatic hypermutation plays a crucial role in the adaptive immune response. By generating a diverse pool of antibodies, the immune system is able to recognize and respond to a wide range of pathogens. The process of somatic hypermutation also allows for the selection of antibodies that have a high affinity for their target antigen, which improves the effectiveness of the immune response.

Clinical Significance

Defects in the process of somatic hypermutation can lead to immunodeficiency disorders, where the immune system is unable to respond effectively to infections. On the other hand, uncontrolled somatic hypermutation can contribute to the development of autoimmune diseases, where the immune system mistakenly attacks the body's own cells.

See also

• Activation-induced cytidine deaminase
• Antibody
• Immunodeficiency
• Autoimmune disease

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  Somatic hypermutation
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  Cytosine chemical structure
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  Uracil