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]
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]
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.