Complement Factor

C3a mediates a variety of proinflammatory
and immunoregulatory functions

The C3a anaphylatoxin is a 78-amino-acid peptide derived from the proteolytic cleavage of the complement protein C3. It mediates a variety of proinflammatory and immunoregulatory functions through its binding to the seven-transmembrane segment G-protein-coupled C3a receptor (C3aR).

  • C3a induces smooth muscle contraction, increases vascular permeability, arachidonic acid metabolism, cytokine release, cellular degranulation and chemotaxis.
  • C3a is involved in microbial host defense, immune regulation and protection against toxic insult.
  • C3a enhances granulocyte adhesion to endothelial and epithelial cell monolayers.
  • Anaphylatoxin C3a inhibits the generation of leukocyte inhibitory factor activity by human mononuclear leukocytes and T lymphocytes cultured with the mitogens in-vitro.


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