ELISA for Detecting SARS-CoV-2 Mutant Strains

SARS-CoV-2, a single stranded RNA virus, has quickly become the subject of much research worldwide. Coronaviruses are composed of four primary proteins: the spike (S), envelope (E), membrane (M), and nucleocapsid (N). The spike protein (S-protein) performs two primary tasks that aid in host infection: 1) mediates the attachment between the virus and host cell surface receptors such as ACE2, and 2) facilitates viral entry into the host cell by assisting in the fusion of the viral and host cell membranes. In December of 2020 three new SARS-CoV-2 variants came to light, UK B.1.1.7, South Africa B.1.351 and Brazil P.1/P.2.

Eagle Biosciences offers a SARS CoV-2 Spike Protein Antigen Quantitative ELISA Assay Kit that is highly sensitive. Clinical studies show that this kit is effective at detecting the spike protein antigen in all three major circulating SARS-CoV-2 variant strains. Click here to learn more.

About the SARS-CoV-2 Spike Protein Antigen Quantitative ELISA Assay Kit

  • Validated for both serum and plasma samples.
  • No cross-reactivity with other respiratory pathogens.
  • Standardization and reproducibility, with lot-to-lot consistency.

Eagle Biosciences is dedicated to providing support to researchers in their studies of SAR-CoV-2 and the new variants. To hear more about our COVID-19 resources and other offerings, contact us here.

25-OH Vitamin D Kits Publication Spotlight

Eagle Biosciences’ Mouse/Rat 25-OH Vitamin D ELISA Assay Kit and 25-OH Vitamin D ELISA Assay Kit were recently utilized in two different publications. One study was looking into the mechanism of how vitamin D can help to protect the liver against non-alcoholic fatty lipid disease (NAFLD) in those with Type 2 diabetes. The other study was focused on how taking α-glucosidase inhibitors (α-GI) with a meal can affect the postprandial bone turnover in overweight or obese individuals.

Learn more about these studies and to read the full text, follow the citations below.

Lim H, Lee H, Lim Y. Effect of Vitamin D3 Supplementaion on Hepatic Lipid Dysregulation Associated with Autophagy Regulatory AMPK/Akt-mTOR Signaling in Type 2 Diabetic Mice. Exp Biol Med. 2021. Full text.

Kreitman A, Schneider SH, Hao L, et al. Reduced Postprandial Bone Resorption and Greater Rise in GLP-1 in Overweight and Obese Individuals After an Alpha-Glucosidase Inhibitor: a Double-Blinded Randomized Crossover Trial. Osteoporos Int. 2021. Full text.

Related Products
25-OH Vitamin D HPLC Assay Kit
25-OH Vitamin D HPLC Column

If you are looking for any other specific related products, or have any questions about the rest of our offerings contact us here. To view our extensive collection of other Vitamin ELISA Assay Kits click here.

RANKL and RANK Biomarker Spotlight

Receptor activator of nuclear factor kappa B ligand, RANKL, and its specific receptor RANK, are members of the tumor necrosis factor (TNF) family and are the main stimulatory factor for the formation of mature osteoclasts and are essential for their survival. The major source of RANKL are osteocytes, former osteoblasts that become embedded within the mineralized bone matrix. RANKL and its specific receptor RANK are not only key regulators of bone remodeling but also play an essential role in immunobiology, e.g. lymph node formation, establishment of the thymic microenvironment, mammary gland development during pregnancy, bone metastasis in cancer and sex-hormone, progestin-driven breast cancer, thermoregulation, and finally in the development of type 2 diabetes mellitus.

A recent study has uncovered a new role for RANKL and RANK in bone remodeling. Researchers have found that extracellular vesicles containing RANKL and RANK may have an important role in the long range signaling for bone remodeling. These signaling molecules have the potential to be targeted for therapeutics and also used diagnostically.

Click here to learn more.

Holliday LS, Patel SS, Rody WJ. RANKL and RANK in Extracellular Vesicles: Surprising New Players in Bone Remodeling. Extracell Vesicles Circ Nucleic Acids. 2021; 2:18-28.

Related Products
Free Soluble RANKL ELISA Assay Kit
iLite® RANKL Assay Ready Cells
Osteoprotegerin ELISA Assay Kit
Sclerostin ELISA Assay Kit

Polystreptavidin R Product Announcement

Eagle Biosciences announces new Polystreptavidin R (Polystrept R) Extraordinary high Biotin binding capacity! This reagent is for surface coating of plastics, membranes, beads and etc. with maximum biotin binding capacity. It improves the signal-noise-relation and saves material costs.

About Streptavidin

Streptavidin is a tetrameric protein (4 x 13 kDa), which binds very tightly to the small molecule Biotin. The binding constant for this interaction is extremely high (Ka ~ 1013 M-1) and turns the Streptavidin/Biotin system into a basis of many biochemical applications. Streptavidin-coated surfaces are characterized by very low nonspecific bindings. Streptavidin coating of solid phases offers a universal immobilization principle for the detection and analysis of proteins, peptides, PCR-fragments etc.

About Polystreptavidin R

Polystreptavidin R is characterized by a immensely high biotin binding capacity in combination with robustness against thermal and chemical influences. Polystreptavidin R is easy to use and suitable for coatings on membranes, beads, microplates, biochips and other plastic materials.

Polystreptavidin R at the strip test (lateral flow assay)

Polystreptavidin R shows outstanding properties when coated on nitrocellulose membranes. The very high biotin binding capacity and the very low washout effects provide a significant signal enhancement at the test line. Highly efficient immobilization of biotinylated molecules and low non-specific binding provide a high signal-to-noise ratio. Polystreptavidin R is a liquid concentrate and can be easily diluted with a neutral buffer for coating or spotting and dried at room temperature without any further production steps. If required, stabilizers can also be added. At temperatures of 2°C to 50°C Polystreptavidin R is stable for at least 24 months and supports a long shelf life.

Why use streptavidin-coated microplates and Polystrept R with lateral flow test strips?

  • Convenient method for a uniform and stable immobilization of biotinylated molecules
  • Immobilization of Biomolecules on solid phases in a directed manner, while avoiding or minimizing denaturation
  • Ready-to-use, no washing or blocking steps required
  • High signal-to-noise ratio
  • Low nonspecific binding
  • Long shelf life
  • Lower reagent consumption and especially enormous cost savings with lateral flow test stripes

Related Products

Ultra-Sensitive Streptavidin Coated Clear 96 Well Microplate
Biotin Microtiter Plate Assay

If you have any questions about Polystreptavidin R or our other offerings, contact us here.


Eagle Biosciences’ COVID-19 IgM and IgG ELISA Assay Kits were recently highlighted in a study. This study evaluated the different tools that have become available for COVID testing and research.


Recent severe acute respiratory syndrome 2 (SARS-CoV-2) known as COVID-19, presents a deadly challenge to the global healthcare system of developing and developed countries, exposing the limitations of health facilities preparedness for emerging infectious disease pandemic. Opportune detection, confinement, and early treatment of infected cases present the first step in combating COVID-19. In this review, we elaborate on various COVID-19 diagnostic tools that are available or under investigation. Consequently, cell culture, followed by an indirect fluorescent antibody, is one of the most accurate methods for detecting SARS-CoV-2 infection. However, restrictions imposed by the regulatory authorities prevented its general use and implementation. Diagnosis via radiologic imaging and reverse transcriptase PCR assay is frequently employed, considered as standard procedures, whereas isothermal amplification methods are currently on the verge of clinical introduction. Notably, techniques such as CRISPR-Cas and microfluidics have added new dimensions to the SARS-CoV-2 diagnosis. Furthermore, commonly used immunoassays such as enzyme-linked immunosorbent assay (ELISA), lateral flow immunoassay (LFIA), neutralization assay, and the chemiluminescent assay can also be used for early detection and surveillance of SARS-CoV-2 infection. Finally, advancement in the next generation sequencing (NGS) and metagenomic analysis are smoothing the viral detection further in this global challenge.

To read more click here.

Oishee MJ, Ali T, Jahan N, et al. COVID-19 Pandemic: Review of Contemporary and Forthcoming Detection Tools. Infect Drug Resist. 2021;14:1049-1082. Published 2021 Mar 17. doi:10.2147/IDR.S289629

Related Products
Coronavirus COVID-19 IgM ELISA Assay Kit
Coronavirus COVID-19 IgG ELISA Assay Kit
COVID-19 Nucleocapsid IgG Quantitative ELISA Assay Kit
COVID-19 S-Protein Specific IgG Quantitative ELISA Assay Kit
COVID-19 Neutralizing Antibody Quantitative ELISA Assay Kit

Osteoprotegerin Biomarker Spotlight

Osteoprotegerin (ORG) is a secreted protein that affects bone turnover and is implicated in heart and kidney disease. It is a glycoprotein of the TNF receptor superfamily 11b (gene name TNFRSF11B). OPG is synthesized as a monomer of 380 amino acids and is assembled as a homodimer within the cell and then secreted mainly as a disulfide-linked homodimer into the extracellular compartment. OPG is produced by many different tissues and cell types including osteoblasts. OPG is a negative regulator of bone resorption by acting as decoy receptor for RANKL, thus neutralizing its function in osteoclastogenesis. This glycoprotein is also involved in the regulation of vascular calcification. A recent study identifies OPG as an independent risk factor for all-cause mortality in patients after kidney transplantation. 982 prevalent kidney transplant (KT) recipients were followed up for all-cause mortality for 6 years. The researchers observed that each 1 pmol/L higher-serum OPG level was associated with a 49% higher risk of mortality.

Association between serum osteoprotegerin level and mortality in kidney transplant recipients. Gupta V et al., 2021. Transpl Int 19. doi: 10.1111/tri.13847. Epub ahead of print. PMID: 33606319.

Osteoprotegerin Related Products

Osteoprotegerin ELISA Assay Kit
Sclerostin ELISA Assay Kit
Periostin ELISA Assay Kit

New Insulin ELISA Assay Kits

Eagle Bioscience’s has extended their line of insulin assays! We now offer a wide range of Insulin ELISA Assay Kits that measure insulin concentration in a number of different species samples. These new kits include the Ovine Insulin ELISA Assay Kit, Equine Insulin ELISA Assay Kit, Porcine Insulin ELISA Assay Kit, Canine Insulin ELISA Assay Kit. These kits are highly sensitive, reliable, and easy to use.

More about insulin:

Insulin is a peptide hormone, produced by beta cells of the pancreas. Enzymatic cleavage of proinsulin results in the production of equimolar amounts of insulin and C-peptide in circulation. Insulin is central to regulating carbohydrate and fat metabolism in the body.  Excessive amounts of insulin are associated with excess amounts of glucose in the system. High levels of insulin are known to cause weight gain, water bloating, high blood pressure, magnesium deficiency and an increase in the amount of inflammatory compounds in the blood, which causes blood clots and blood vessel damage. Insulin, when insufficiently produced, results in diabetes mellitus. In most cases, a high fasting insulin level is consistent with insulin resistance symptoms, but in some cases, it can be caused by more serious conditions such as Cushing’s syndrome, acromegaly or possibly insulinoma.

Related Insulin ELISA Assay Kits:

Proinsulin ELISA Assay Kit

Insulin ELISA Assay Kit

Insulin Ultrasensitive ELISA Assay Kit

If you are looking for any other specific related products, or have any questions about our offerings contact us here.

iLite Assay Ready Cells

iLite® Assay Ready Cells are developed by our partners at Svar Life Science. iLite technology is based upon a reporter gene assay format, modified and adapted for applications during the whole drug development cycle as well as for monitoring of biological drugs. These cell lines can be developed for any biopharmaceutical target and assays for drug potency, i.e. drug activity, and neutralizing antibodies (NAbs) can easily be set-up using the same cell line. The Assay Ready cells are genetically engineered to be used with a reporter gene assay technique for detection the the drug potency and the NAbs.

A Message from SVAR about iLite:

“Many therapeutic antibodies that are used to treat common disorders, such as cancer and autoimmune diseases work – at least in part – by activating ADCC.

Our reporter gene-based iLite® ADCC bioassays offer a convenient and powerful way of measuring the ability of an antibody to elicit ADCC.

Read our new white paper and learn about the performance of our ADCC bioassays and how they compare to a leading competitor in terms of sensitivity and dynamic range.”

Download the White Paper here.

Find all of the iLite products offered on the iLite Assay Ready Cells product page.

DHEA ELISA Publication

Evidence for fasting induced extra-adrenal steroidogenesis in the male brown anole, Anolis sagrei

The Eagle Biosciences DHEA ELISA was used in a recent study testing if fasting could induce adrenal tissues to produce glucocorticoids (GCs) and dehydroepiandrosterone (DHEA) to coordinate different physiological processes.


Glucocorticoids (GCs) and dehydroepiandrosterone (DHEA) are steroids secreted by the adrenal glands into circulation to effect distant target tissues and coordinate physiological processes. This classic systemic view of steroids has been challenged by evidence that other tissues can independently synthesize their own steroids. Little is known however regarding circumstances that can promote this extra-adrenal steroidogenesis. Here we tested if fasting can induce tissues to increase GC and DHEA synthesis in the brown anole lizard Anolis sagrei. Lizards fasted for eight days lost body mass and increased fatty acid oxidation. Fasting also increased plasma concentrations of DHEA and corticosterone, but not cortisol. Corticosterone concentration within the adrenals, heart, intestines, lungs and liver exceeded that in plasma, with the latter two increasing with fasting. Levels of DHEA in the adrenals and heart were higher than in plasma, but no significant effect of fasting was observed, expect for a noticeable increase in intestinal DHEA. Two steroidogenic genes, the steroidogenic acute regulatory (Star) protein and Cyp17a1, a cytochrome P450 enzyme, were expressed in several tissues including the liver, lungs and intestines, which were increased with fasting. Continued research should aim to test for expression of additional enzymes further along the steroidogenic pathway. Nonetheless these data document potential extra-adrenal steroidogenesis as a possible mechanism for coping with energy shortages, although much work remains to be done to determine the specific roles of locally synthesized steroids in each tissue.

To learn more and read the full publication, click here.

Related Products:

DHEA Saliva Sensitive ELISA

Big Endothelin-1 Biomarker Spotlight

Big Endothelin-1 (Big ET-1) is a protein that is mainly produced by vascular endothelial and smooth muscle cells and cardiomyocytes. Big ET-1 is a precursor to Endothelin (ET), the most potent vasoconstrictor known today. The half life of ET is less than one minute, whereas Big ET-1 is cleared more slowly. Big ET-1 can therefore be determined more easily, and has since been identified as a risk factor for a poor prognosis in patients with atrial fibrillation or coronary artery disease. A current study has shown that plasma concentrations of Big ET-1 is a valuable tool for risk stratification in patients with left ventricular non-compaction cardiomyopathy (LVNC). Other studies have also recognized the effectiveness of Big ET-1 as a predictor for numerous cardiovascular diseases.

Prognostic value of plasma big endothelin-1 in left ventricular non-compaction cardiomyopathy. Fan P, et al. Heart 2020;0:1–6. doi:10.1136/heartjnl-2020-317059

Plasma big endothelin-1 is an effective predictor for ventricular arrythmias and end-stage events in primary prevention implantable cardioverter- defibrillator indication patients. Li XY et al., 2020. J Geriatr Cardiol 28;17(7):427-433.

Plasma big endothelin-1 predicts new-onset atrial fibrillation after surgical septal myectomy in patients with hypertrophic cardiomyopathy. Song C et al., 2019. BMC Cardiovasc Disord 22;19(1):122.

Plasma level of big endothelin-1 predicts the prognosis in patients with hypertrophic cardiomyopathy. Wang Y et al., 2017. Int J Cardiol 15;243:283-289.

Related Products:

Big Endothelin-1 ELISA Assay Kit.
NT-proANP ELISA Assay Kit
NT-proCNP ELISA Assay Kit
BNP Fragment ELISA Assay Kit

If you have any questions regarding our Big Endothelin-1 ELISA Assay Kit or any other kits in the Cardiovascular Assay line, contact us here.