Serum Amyloid A Recombinant Rabbit mAb (S-5308)

Serum Amyloid A (SAA) is an acute-phase reactant protein synthesized by hepatocytes and secreted into the bloodstream. Under normal physiological conditions, its serum concentration is extremely low; however, during acute-phase responses such as infection, inflammation, or tissue injury, its levels can surge dramatically by hundreds to thousands of times within hours. Structurally, SAA is an apolipoprotein that primarily associates with high-density lipoprotein (HDL) and can interact with cholesterol and phospholipids through its N-terminal α-helical domain, thereby participating in the regulation of lipid metabolism. Functionally, SAA plays multifaceted roles in immune defense and inflammatory regulation: it can recruit immune cells such as monocytes and neutrophils to sites of inflammation through chemotaxis, induce the release of various pro-inflammatory cytokines, and participate in antigen presentation and immune response modulation. However, dysregulation of SAA function is closely associated with various diseases; persistently elevated SAA levels serve as a biomarker for chronic inflammatory diseases such as rheumatoid arthritis and atherosclerosis. In amyloidosis, proteolytic fragments of SAA can deposit in tissues to form amyloid A (AA) fibrils, leading to multi-organ dysfunction. Additionally, within the tumor microenvironment, SAA has been found to promote tumor invasion and metastasis. Due to its high sensitivity to inflammation, SAA has become an important serological marker for the differential diagnosis of infection and inflammation in clinical practice.