Mast cell

Mast cells in cell culture

Mast cells (mastocytes) are cells of the body's own defense system that have stored messenger substances , including histamine and heparin . They are 20-30 µm in size.

Paul Ehrlich discovered them and called them “mast cells”, probably because he wrongly assumed that the cells had the ability to phagocytose . However , the cells themselves produce the granules stored in it . Another version says that Ehrlich assumed that these cells use their fatty granules to feed or “fatten” surrounding cells.

The basophilic granulocytes , sometimes also referred to as blood mast cells, differ from the actual mast cells. The latter occur throughout the body in the interstitial connective tissue , but most often in the submucosa of the intestine and airways and in the dermis (corium), near vessels and nerves.

The mast cell plays an important role in type 1 allergies ( IgE- mediated allergies such as asthma , allergic rhinitis, systemic anaphylaxis): When the person first comes into contact with an allergen , the person concerned initially remains completely symptom-free, but the formation of specific IgE antibodies triggered by the plasma cells that are directed against the specific allergen. The mass-produced IgE antibodies attach themselves to the foot part (Fc part = fragment crystallizable) on the surface of mast cells, which are found everywhere in the body, especially in the mucous membranes, and sensitize them to the reaction to the allergen. An allergic reaction only occurs on the second contact with the allergen, when the allergens bind to two neighboring IgE antibodies on the mast cells and these are linked to one another. This stimulates the mast cells to empty their granules during the exocytosis process and to release the histamine they contain ( degranulation ). Histamine is a messenger substance that binds to receptors in the surrounding tissue cells and causes violent effects in a few seconds. This process is known as an immediate allergic reaction ( immune response ), as the allergic symptoms appear within seconds to minutes. The rapid onset of symptoms is due to the immediate reaction of the surrounding tissue to the secreted substances: vessels expand, fluid accumulates (wheals), etc. The numerous mast cells positioned near the vessels actively wait for IgE.

There is also a non-immunological degranulation of mast cells. This means that a release reaction (as described in the above paragraph) also takes place, i.e. histamine, heparin and other mediators are released by mast cells, but without the involvement of antibodies. Certain molecular structures, e.g. B. from drugs, are able to trigger the nonimmunological mast cell degranulation.

The number of mast cells increases with age, so it is assumed that mast cells and their ingredients contribute to the aging process. In addition to the above-mentioned role in triggering allergic symptoms, the mast cell is also of central importance in other diseases such as urticaria and mastocytosis . The physiological functions of mast cells lie primarily in the defense against bacteria and parasites as well as in protection against animal toxins .

literature

• P. Volna, P. Lebduska, L. Draberova, S. Simova, P. Heneberg, M. Boubelik, V. Bugajev, B. Malissen, BS Wilson, V. Horejsi, M. Malissen, P. Draber: Negative regulation of mast cell signaling and function by the adapter LAB / NTAL. In: J Exp Med . 200 (8), 2004 Oct 18, pp. 1001-1013.
• P. Heneberg, P. Draber: Regulation of cys-based protein tyrosine phosphatases via reactive oxygen and nitrogen species in mast cells and basophils. In: Curr. Med. Chem. 12 (16), 2005, pp. 1859-1871.

Web links

• electron microscopic images of mast cells

Individual evidence

1. ^ Mast cell , Division d'Histologie de l'Université de Friborg
2. ↑ LE Cheng: Perivascular mast cells dynamically probe cutaneous blood vessels to capture immunoglobulin E. In: Immunity . 38 (1), 2013 Jan 24, pp. 166-175. doi: 10.1016 / j.immuni.2012.09.022 .
3. ↑ biomedgerontology.oxfordjournals.org
4. ↑ Stephen J Galli, Niels Borregaard, Thomas A Wynn: Phenotypic and functional plasticity of cells of innate immunity: macrophages, mast cells and neutrophils . In: Nature Immunology . tape 12 , no. 11 , p. 1035-1044 , doi : 10.1038 / ni.2109 , PMID 22012443 , PMC 3412172 (free full text) - ( nature.com ).
5. ↑ Martin Metz, Adrian M. Piliponsky, Ching-Cheng Chen, Verena Lammel, Magnus Åbrink: Mast Cells Can Enhance Resistance to Snake and Honeybee Venoms . In: Science . tape 313 , no. 5786 , July 28, 2006, ISSN  0036-8075 , p. 526-530 , doi : 10.1126 / science.1128877 , PMID 16873664 ( sciencemag.org [accessed June 15, 2017]).