Human SOST/Sclerostin Quantikine ELISA Kit Summary

Product Summary

The Quantikine Human SOST immunoassay is a 4.5 hour solid-phase ELISA designed to measure SOST in human cell culture supernates, serum, and plasma. It contains NS0-expressed recombinant human SOST and antibodies raised against the recombinant factor. This immunoassay has been shown to accurately quantitate the recombinant human SOST. Results obtained using natural human SOST showed dose response curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for natural SOST.

Preparation and Storage

Background: SOST/Sclerostin

SOST, also known as Sclerostin, is a Cerberus/DAN family BMP antagonist and is an important regulator of bone homeostasis. Inactivating mutations in the SOST gene can cause sclerosteosis and van Buchem disease. SOST is expressed by terminally differentiated cells embedded in mineralized matrix including osteocytes, hypertrophic and prehypertrophic chondrocytes, and tooth cementocytes. Its expression is induced by BMP-2, -4, and -6 and is inhibited by parathyroid hormone (PTH). Its downregulation in osteocytes by physical loading of bone contributes to the mechanical sensor function of osteocytes and the subsequent increase in bone growth. SOST binds to BMP-2, -4, -5, -6, and -7 and inhibits the osteogenic differentiation induced by these BMPs. It inhibits canonical Wnt signaling by binding to LRP-5 and LRP-6 and inhibiting their association with Frizzled receptors. SOST reduces the proliferation of mesenchymal stem cells (MSC) and induces MSC apoptosis. Circulating levels of SOST are elevated in pathologies with bone involvement including low bone mineral density, Paget’s disease, multiple myeloma, and prostate cancer with bone metastases. It is also elevated in advanced chronic kidney disease, alcoholic liver disease, type 2 diabetes, and patients with increased abdominal and gynoid fat.

Assay Procedure

Refer to the product datasheet for the complete assay procedure.

Bring all reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate.

1、Prepare all reagents, standard dilutions, and samples as directed in the product insert.

2、Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.

3、Add 50 μL of Assay Diluent to each well.

4、Add 50 μL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at room temperature for 2 hours.

5、Aspirate each well and wash, repeating the process 4 times for a total of 5 washes.

6、Add 100 μL of Conjugate to each well. Cover with a new plate sealer, and incubate at room temperature for 2 hours.

7、Aspirate and wash 5 times.

8、Add 100 μL Substrate Solution to each well.

9、Add 100 μL of Stop Solution to each well. Read at 450 nm within 30 minutes. Set wavelength correction to 540 nm or 570 nm.