Serum Amyloid A-4 protein ELISA Kit (SAA4)

Full Name: Serum Amyloid A-4 protein ELISA Kit (SAA4)
Reactivity: Human
Sample Type: Plasma, Tissue Homogenates, Serum, Biological Fluids
Sensitivity: 0.188 ng/ml

INTRODUCTION

SAA4, known as Serum Amyloid A-4 Protein, is a human protein mainly produced by the liver that circulates in blood plasma and plays a role in the acute immune response. As an apolipoprotein constituent of High Density Lipoprotein particles in blood, SAA-4 is important for cholesterol metabolism and transport.

During the early “acute phase” of inflammation from illness or trauma, the liver rapidly ramps up production of SAA4 several hundred-fold before returning to normal levels once inflammation resolves. This surge helps mobilize immune cells via cytokines and cell surface receptors. Specifically, higher circulating SAA4 prompts immune cells like monocytes, neutrophils, and T-lymphocytes to migrate from blood into affected tissues by making blood vessels more permeable. SAA-4 additionally induces macrophages within injured sites to eliminate pathogens through phagocytosis and secretion of microbe-destroying enzymes. However, prolonged high levels may eventually contribute to chronic inflammatory disorders.

Beyond infection-induced inflammation, SAA4 production also increases after acute tissue injury, like myocardial infarction. Early elevation following heart attack is linked to larger subsequent scar size and worse recovery. This reflects how the protein’s pro-inflammatory effects, while helpful in resolving acute damage, can cause excessive collateral tissue irritation when unchecked. Carefully regulated SAA4 signaling is thus crucial for balanced, productive inflammatory response without unintended effects.

INTENDED USE

Human serum amyloid A-4 protein ELISA kit can measure concentrations of SAA4 (serum amyloid A-4 protein, CSAA, C-SAA, SAA5) present is plasma, serum, biological fluids or tissue homogenate samples.

CONTENT

All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

• One 96-Well Plate: Pre-coated with anti-SAA4.
• Standards: Lyophilized recombinant.
• Sample/Standard Dilution Buffer.
• Biotinylated-labelled Antibody.
• Antibody Dilution Buffer.
• HRP-Streptavidin Conjugate (SABC).
• SABC Dilution Buffer.
• TMB Substrate.
• Wash Buffer (25x).
• Plate Sealer.
• Product Instructions.

TYPICAL RESULTS

For this SAA4 ELISA kit, it is recommended that a standard curve is generated for each assay carried out.

Standard Curve: 0, 0.312, 0.625, 1.25, 2.5, 5, 10, 20 ng/ml.
Reactivity: Human
Sensitivity: 0.188 ng/ml
Range: 0.313 – 20 ng/ml
Principle: Sandwich, Double Antibody
Application: Research Use Only.

ASSAY CHARACTERISTICS

– Specificity: Highly specific for SAA4, no cross reactivity or interference between SAA4 and analogues was detected.
– Recovery: Serum (86 – 103%), EDTA Plasma (90 – 102%), Heparin Plasma (86 – 105%).
– Linearity: Serum (85 – 99%), EDTA Plasma (88 – 101%), Heparin Plasma (83 – 100%).
– Precison Intra-Assay: CV < 8%
– Precison Inter-Assay: CV < 10%

REFERENCES

1. The human serum amyloid A locus SAA4 is a pseudogene. Biochem Biophys Res Commun. (1992) 183 (2): 362-6. Sack G.H. Jr and Talbot C.C. Jr.
2. Serum Amyloid A 4 as a Common Marker of Persistent Inflammation in Patients with Neovascular Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy. J Inflamm Res. (2023) 16: 3783-3797. Liu Q., et al.
3. Structure of the mouse Saa4 gene and its linkage to the serum amyloid A gene family. Genomics. (1996) 34 (1): 139-42. de Beer M.C., et al.
4. Analysis of the genomic and derived protein structure of a novel human serum amyloid A gene, SAA4. Scand J Immunol. (1992) 36 (5): 703-12. Watson G., et al.

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