Immunoglobulin family

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A group of functionally and structurally related proteins that play a key role in the immune system is called the large immunoglobulin family (immunoglobulin superfamily). The immunoglobulins include antibodies, specific receptors for T-lymphocyte and B-lymphocytes, HLA molecules, adhesion molecules, and growth factor receptors. They are expressed mainly on leukocytes, but some are also found on other cells (e.g. HLA class I on all nuclear cells). They occur as free molecules or are incorporated into the cell membrane.

Immunoglobulin domain[edit | edit source]

Immunoglobulin basic unit

A characteristic feature of immunoglobulins is the presence of the so-called immunoglobulin domain in their structure. The domains contain about 100 amino acids. They have a globular structure. The peculiarity is that they form incomplete rings connected by a sulphide bridge of two cysteines (see figure). Immunoglobulin domains are classified according to their variability within a single type of molecule.

Variable[edit | edit source]

Domains with high variability (hypervariable). They are usually found in the part of the molecule that contacts the antigens or ligands. They are referred to as V 1-n.

Searchtool right.svg For more information see Genetics of Ig, B and T receptors.

Constant[edit | edit source]

This type of immunoglobulin domain is characteristic of single molecules. They further determine the reaction upon ligand binding. They are referred to as C 1-n.

Transient[edit | edit source]

Domains that retain a partially constant form but may vary are called transient. They are denoted H1-n.

Function of immunoglobulins[edit | edit source]

All immunoglobulin molecules are able to recognize their specific ligands (with varying degrees of accuracy). They are therefore essential agents in specific immunity.

Links[edit | edit source]

Related articles[edit | edit source]

Used literature[edit | edit source]

  • ŠTERZL, Ivan, et al. Základy imunologie pro zubní a všeobecné lékaře. 1. edition. Praha : Karolinum, 2005. 207 pp. ISBN 978-80-246-0972-0.