anaphylatoxin


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anaphylatoxin

 [an″ah-fil´ah-tok″sin]
a substance produced by complement activation that causes the release of histamine and other mediators of immediate hypersensitivity from basophils and mast cells, thereby producing signs and symptoms of immediate hypersensitivity (anaphylaxis) without involvement of IgE.

an·a·phyl·a·tox·in

(an'ă-fil-ă-tok'sin),
Low molecular weight cleavage products (C3a, C4a, and C5a); generated by the activation of the complement cascade. They are proinflammatory; can cause permeability, smooth muscle contraction, and mask cell degranulation.
Synonym(s): anaphylotoxin
[anaphylaxis + toxin]

anaphylatoxin

(1) Any antigen that reacts with an IgE and precipitates an anaphylactic reaction by stimulating histamine release.
(2) Activated complement fragments (C3a, C4a and C5a) that bind to mast cells and basophils and trigger the release of inflammatory mediators.

an·a·phyl·a·tox·in

, anaphylotoxin (an'ă-fil'ă-tok'sin, an'ă-fil'ō-tok'sin)
1. A substance postulated to be the immediate cause of anaphylactic shock and that is assumed to result from the in vivo combination of specific antibody and the specific sensitizing material.
2. The small fragment (C3a) split from the third component (C3) of complement, which produces a local wheal following intracutaneous injection.

anaphylatoxin

Any substance that can directly cause degranulation of MAST CELLS thereby bringing about an acute allergic reaction.
References in periodicals archive ?
demonstrated that the anaphylatoxins C3a are essential for liver regeneration.17 C3 deficiency results in diminished liver regeneration, accompanied by transient or fatal liver failure after partial hepatectomy.17 Muller et al.
In these studies, we showed that Bothrops venoms triggered the C-cascade by one or several activation pathways, generating high quantities of anaphylatoxins by directly cleaving C3 and C5 or by inactivating the regulator C1-INH.
Neal et al., "The receptor for complement anaphylatoxin C3a is expressed by myeloid cells and nonmyeloid cells in inflamed human central nervous system: analysis in multiple sclerosis and bacterial meningitis," The Journal of Immunology, vol.
Carboxypeptidase N was reported to disrupt the activity of the anaphylatoxin C3a because ASP cannot mediate many of the proinflammatory activities associated with C3a (17, 18).
Doumas et al., "Complement anaphylatoxin C5a contributes to hemodialysis-associated thrombosis," Blood, vol.
Mukhopadhyay et al., "Anaphylatoxin C5a contributes to the pathogenesis of cisplatin-induced nephrotoxicity," American Journal of Physiology-Renal Physiology, vol.
With anaphylatoxin discovered in the serum [16] and histamine shown to be involved in smooth muscle contraction [17] different molecules were proposed as key candidates responsible for such reactions.
Role of C3, C5 and anaphylatoxin receptors in acute lung injury and in sepsis.
Furthermore, complement activation may potentiate platelet function (29, 30), as platelet activation and aggregation are directly induced by the anaphylatoxin complement C3a and its derivatives, which are activation products of complement C3 (31, 32).
(12) Other non-immunologic stimuli including opiates, C5a anaphylatoxin, stem cell factor and some neuropeptides (e.g.
Anaphylatoxin C5a modulates hepatic stellate cell migration.
C5a interacts with the receptor for complement anaphylatoxin (C5a receptor) localized on the surface of mast cell MCtc, the subtype dominant in the skin, and participates in mast cell activation [20].