C3a
C3a[edit | edit source]
C3a is a small protein fragment that plays a crucial role in the immune system, particularly in the complement system. It is one of the anaphylatoxins, which are peptides that cause rapid degranulation of mast cells and basophils, leading to the release of histamine and other mediators of inflammation.
Structure and Formation[edit | edit source]
C3a is derived from the cleavage of the complement component C3, a central protein in the complement system. The cleavage is typically mediated by the enzyme C3 convertase, which splits C3 into C3a and C3b. C3a is a 77-amino acid peptide that is released into the bloodstream, while C3b remains bound to the pathogen surface, facilitating opsonization and phagocytosis.
Function[edit | edit source]
C3a functions primarily as an anaphylatoxin. It binds to the C3a receptor (C3aR) on the surface of various immune cells, including mast cells, basophils, and eosinophils. This binding triggers a cascade of events leading to:
- Degranulation of mast cells and basophils: This results in the release of histamine, which increases vascular permeability and smooth muscle contraction, contributing to the inflammatory response.
- Chemotaxis: C3a acts as a chemoattractant, recruiting immune cells to the site of infection or injury.
- Modulation of immune responses: C3a can influence the adaptive immune response by affecting the function of dendritic cells and T cells.
Clinical Significance[edit | edit source]
Excessive activation of C3a can contribute to pathological conditions such as anaphylaxis, asthma, and other allergic reactions. Conversely, deficiencies in C3a production or function can impair the immune response, leading to increased susceptibility to infections.
Research and Therapeutic Potential[edit | edit source]
Research into C3a and its receptor has led to the development of potential therapeutic agents aimed at modulating its activity. These include C3a receptor antagonists, which are being investigated for their potential to treat inflammatory and autoimmune diseases.
Also see[edit | edit source]
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
|
WikiMD's Wellness Encyclopedia |
| Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD
