desArgC5a

desArgC5a, or desarginine C5a, is a biologically active fragment of the complement protein C5 generated during the complement cascade, a part of the immune system's response to pathogens. It is produced when the enzyme C5 convertase cleaves C5 into two fragments: C5a and C5b. The C5a fragment is further processed by the enzyme carboxypeptidase B to remove its N-terminal arginine residue, yielding desArgC5a.

desArgC5a retains many of the biological activities of its precursor, C5a, but with some functional differences. It serves as a potent anaphylatoxin, meaning it promotes inflammation by stimulating the release of histamine from mast cells and basophils. This contributes to increased vascular permeability, smooth muscle contraction, and recruitment of immune cells to sites of infection or injury. Unlike C5a, desArgC5a is more resistant to degradation by proteases, extending its half-life in circulation.

The primary role of desArgC5a is to amplify immune responses. It enhances phagocytosis by neutrophils and macrophages, promotes the production of reactive oxygen species, and stimulates the expression of adhesion molecules on endothelial cells, facilitating leukocyte extravasation. Additionally, desArgC5a acts as a chemotactic factor, guiding neutrophils, monocytes, and other immune cells toward sites of inflammation or infection.

Studies have also linked elevated levels of desArgC5a to various pathological conditions, including sepsis, autoimmune diseases, and certain inflammatory disorders. Its prolonged presence in tissues may contribute to chronic inflammation and tissue damage, highlighting its dual role in both protective immunity and disease pathogenesis. Research continues to explore its potential as a therapeutic target in inflammatory and autoimmune diseases.