Two Independent Research Teams Find Possible Link Between Neuropilin-1 and SARS-CoV-2 Transmission
Neuropilin-1 (NRP1) is an essential transmembrane cell surface receptor acting primarily as a co-receptor for various ligands (i.e. VEGF, Semaphorins). Due to alternative splicing or shedding, the extracellular region can be released into circulation as soluble Neuropilin-1. NRP1 functions in many key biological processes including the neuronal, cardiovascular and the immune system. The virus SARS-CoV-2 is the causative agent of the coronavirus disease COVID-19 NRP1 is expressed in multiple cell types in the body but occurs primarily on cells in the lung, nose and brain (i.e. respiratory and olfactory epithelium as well as in the CNS). SARS CoV 2 enters the host cells by its spike proteins mainly through its binding to the angiotensin converting enzyme 2 (ACE2).
Neuropilin-1 facilitates SARS-CoV-2 cell entry and provides a possible pathway into the central nervous system. Cantuti-Castelvetri L et al., Science 13 Nov, 2020; Vol. 370, Issue 6518, pp. 856-860. Full publication.
Neuropilin-1 is a host factor for SARS-CoV-2 infection. Daly JL et al., Science, 13 Nov 2020; Vol. 370, Issue 6518, pp. 861-865. Full publication.
Eagle Biosciences is now offering a new Human VEGF ELISA Kit from Biomedica. The VEGF ELISA Assay Kit is intended for the quantitative determination of human VEGF in serum, EDTA plasma, and citrate plasma.
VEGF ELISA Highlights:
DAY Test – results in 4.5 h
High sensitivity – measurable values in both serum and plasma
RELIABLE- rigorously validated according to FDA/ICH/EMA guidelines
READY to use – calibrators and controls included
EXCELLENT correlation to existing methods
SMALL sample size – only 10µl sample / well required
Areas of interest:
Metabolic disease (diabetes and diabetic kidney disease, diabetic retinopathy, obesity)
Vascular endothelial growth factor (VEGF or VEGF-A), is a growth hormone secreted by endothelial cells, ﬁ broblasts, smooth muscle cells, platelets, macrophages, and many other cell types. It belongs to the cysteine-knot growth factor superfamily (1) and has a molecular weight of about 40 kDa. Currently, 17 different VEGF isoforms have been described to be expressed from one single gene. They are produced by alternative promoter usage/initiation or alternative splicing/proteolysis after protein translation. The N-terminal region is responsible for receptor binding and conserved among all VEGF isoforms. In contrast, residues of the C-terminus differ between isoforms and determine protein length and properties: binding to co-receptor Neuropilin-1 (NRP1) or to extracellular matrix (ECM), agonist/antagonist of angiogenesis. Most isoforms result from the common transcripts: VEGF111, VEGF121, VEGF145, VEGF165, VEGF189 and VEGF206. Additionally, a third VEGF variant (VEGFAx), that demonstrates pro- and anti-apoptotic properties, was described. Thus, vascularization is tightly controlled by the balance of various splice variants, their availability and concentration, whereas isoforms linked to the ECM constitute a reservoir of VEGF that can quickly be shed to circulating forms. One of the most potent pro-angiogenic isoforms is VEGF165a. After secretion, 50-70% of VEGF165a is attached to the extracellular matrix (via heparin binding site), the rest is freely diffusible. It is the most abundant isoform and enhances signaling over the VEGFR2 receptor by additionally binding to its co-receptor Neuropilin-1. VEGF A isoforms are glycosylated, homodimeric proteins. Two anti-parallel monomers are linked by intermolecular disulfide bonds whereas eight cysteine residues form a knot-like structure at one end of each monomer. However, heterodimerization with PLGF has been described as well.
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Diagomix develops and manufactures antibodies, products for immunohistochemistry, ELISA, lateral flow assays and other antibody-based tests. Founded by a team of biomedical professionals, they offer a wide range of biochemical product development services. Their areas of focus include immunohistochemical diagnostics, companion diagnostics, food safety, and hapten detection.
LEUCINE-RICH ALPHA-2-GLYCOPROTEIN (LRG) ELISA Now Available!
Austrian supplier Biomedica has released a new ELISA, the Leucine-Rich Alpha-2-Glycoprotein or LRG for short. The LRG ELISA Assay kit is intended for the quantitative determination of human LRG in serum, EDTA plasma, heparin plasma, and citrate plasma.
LRG (leucine-rich alpha-2-glycoprotein) is a glycoprotein with a molecular mass of 38.2 kDa. It is encoded by the human gene LRG-1 which is mapped on chromosome 19 at the cytogenetic band 19p13.3. The protein LRG (or also named LRG1) runs at approximately 50 kDa under reducing conditions, as it contains a carbohydrate content of 23%. LRG is the founding member of the family of leucine-rich repeat proteins. The mature protein consists of 312 amino acids, from Val36 to Gln347, with a leucine content of 66 amino acids. LRG is folded to eight leucine-rich repeat (LRR) domains of 22 amino acid length, and a C-terminal LRRCT domain with 49 amino acid length. Human LRG shows 62.5% sequence identity with mouse LRG, and 60.7% with rat LRG.
LRG binds to the TGFβ accessory receptor endoglin, and in the presence of TGFβ1 this leads to the induction of the TβRII-ALK1-Smad1/5/8 signaling pathway. TGFβ1 therefore promotes binding of LRG to the proangiogenic ALK1 but inhibits the interaction with angiostatic ALK5. Induced signaling leads to endothelial cell proliferation and blood vessel outgrowth.
Like many other family members of the leucine-rich repeat (LRR) family, LRG has multiple binding partners. LRG directly interacts with the mitochondrial electron transfer protein cytochrome c, whereas the physiological relevance of this interaction is not yet known. LRG further binds to TGFβ1, the most frequently expressed TGFβ isoform.
The tissue distribution of LRG varies, with high-level expression in the liver, lower expression in the heart, and minimal expression in spleen and lung. LRG is expressed during hematopoiesis. It plays a role in the innate immune system as it is upregulated during neutrophil differentiation; LRG is packed into peroxidase-negative granules of human neutrophils and then secreted upon activation to modulate the microenvironment. Differential expression of LRG is further associated with certain carcinomas, neurodegenerative disease, aging or autoimmune disease. In addition, studies have demonstrated an association between cardiac remodeling (hypertrophy, fibrosis, abnormal vasculature, heart failure) and reduced expression of LRG.
LRG is involved in cell proliferation and immune response, in cell migration, neovascularization and apoptosis. It is a proangiogenic factor which is involved in the regulation of the TGFβ signaling pathway. Up-regulation of LRG is described in response to acute phase response in hepatocytes.
LRG is potentially a biomarker for a variety of diseases e.g. as inflammatory biomarker for autoimmune diseases such as rheumatoid arthritis and inflammatory bowel disease. Numerous groups have shown that LRG is increased in various immune-related diseases such as psoriasis, juvenile idiopathic arthritis, Kawasaki disease, appendicitis, and cancers, indicating that LRG elevation is not only limited to autoimmune diseases. In addition, LRG may serve as a biomarker for several other disease conditions such as heart failure, and diabetes-related complications. Plasma Leucine-Rich α-2-Glycoprotein has also been demonstrated to predict cardiovascular disease risk in end-stage renal disease. Leucine-rich α-2-glycoprotein is highly expressed in the brain and it is possible to distinguish idiopathic normal pressure hydrocephalus (iNPH) from other neurodegenerative diseases such as Alzheimer disease by measuring LRG in cerebrospinal fluid.
Epitope Diagnostics Inc. New COVID-19 IgG and IgM ELISA Featured in Icelandic Study on Humans Immune Response to SARS-CoV-2 Exposure
A study has recently been published in the New England Journal of Medicine titledHumoral Immune Response to SARS-CoV-2 in Iceland by D.F. Gudbjartsson, et. al. This study takes a look at the semi-long term immune response of the COVID-19 respiratory infection. 30,576 patient samples were tested for both IgG and IgM antibodies using both q-PCR and ELISA methods. The ELISA’s used in this study were the Coronavirus COVID-19 IgG ELISA Assay and Coronavirus COVID-19 IgM ELISA Assay Kit offered by Eagle Biosciences. The results of this study showed that IgM anti-N antibody levels increased rapidly soon after diagnosis and then fell rapidly and were generally not detected after 2 months. IgG anti-N and anti-S1 antibody levels increased during the first 6 weeks after diagnosis and then decreased slightly, indicating that antiviral antibodies against SERS-CoV-2 did not decline within 4 months after diagnosis. With respect to clinical characteristics, antibody levels were most strongly associated with hospitalization and clinical severity, followed by clinical symptoms such as fever, maximum temperature reading, cough, and loss of appetite. Severity of these individual symptoms, with the exception of loss of energy, was associated with higher antibody levels.
More research still needs to be conducted to understand the full immune response over time. However, this is a great step in the development of how this virus works and how the world will be able to overcome it.
To learn more and read the full publication, click here.
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For this study, two biomarkers in human plasma were measured; neurofilament light chain protein (NfL) and glial fibrillary acidic protein (GFAP). The samples came from patients who had mild, moderate or severe cases of COVID-19 (n=47). Of those 47 patients, the ones who had a severe case of COVID-19 showed higher concentrations of GFAP and NfL.
Glial Fibrillary Acidic Protien, or GFAP for short, is a known biomarker in the central nervous system (CNS) that is typically studied in those with brain injuries. When a brain injury occurs (concussion, retinal stess, tumors, etc.), GFAP is released into the blood stream and helps determine the severity of the injury. The results of this study help support and determine the relationship between COVID-19 and potentially lasting neural injuries.
The iLite® C5a Assay Ready Cells can be used for the quantification of C5a activity, and for determination of inhibitory activity against either C5a itself or against the C5a receptor in test samples, including human serum.
The iLite® RANKL Assay Ready Cells can be used for the quantification of RANKL activity, RANKL inhibitor activity or immunogenicity studies and determination of neutralizing antibody response against RANKL inhibitors in test samples, including human serum.
Comparison of the Elecsys® Anti-SARS-CoV-2 immunoassay with the EDITM enzyme linked immunosorbent assays for the detection of SARS-CoV-2 antibodies in human plasma
Both of Epitope Diagnostics’ Anti-SARS-COV-2 antibody assays (IgG and IgM) have been featured in a head-to-head comparison against Elecsys® Anti-SARS-CoV-2. Elecsys® Anti-SARS-CoV-2 is manufactured by Roche Diagnostics and has been the gold-standard in the diagnostics industry for automated assays.
Abstract:Recently, Roche Diagnostics (Rotkreuz, Switzerland) has launched the IVD CE-marked Elecsys® Anti-SARS-CoV-2 assay for the qualitative detection of SARS-CoV-2 antibodies on the cobas e immunoassay analyzers. The aim of this study was to compare the clinical performance of the Elecsys® Anti-SARS-CoV 2 assay with the EDITM SARS-CoV-2 IgM and IgG enzyme linked immunosorbent assays (ELISA), which we have recently established in our laboratory.
We, at Eagle Biosciences, Inc. are rapidly expanding our selection of Coronavirus Assays by welcoming two new research kits! With the ongoing pandemic, it’s more important now than ever that we continue to offer the highest quality assays to our customers. Here are our newest additions;
The Anti-SARS-CoV-2 S1 (RBD) IgG ELISA Assay Kit is manufactured in Germany by Mediagnost. This assay is a highly specific enzyme immunoassay for the detection of IgG antibodies directed against SARS-CoV-2-S1 Receptor Binding Domain (RBD) in human blood. In this assay the recombinant Receptor Binding Domain (RBD) of SARS-CoV-2 S1 spike protein, which binds the ACE2 receptor, is used. The use of RBD increases the specificity of the assay since the domain is identical with SARS-CoV but not with MERS-CoV for example. Antibodies directed against the RBD neutralize both virus strains SARS-CoV and SARS-CoV-2.
Size: 1×96 wells Incubation Time: 2 hours 40 minutes Sample Type: Serum and Plasma Sample Size: 100 µl Controls Included
To learn more about the Anti-SARS-CoV-2 S1 (RBD) IgG ELISA Assay click here*
The Anti-SARS-CoV-2 (S1, S2, N) IgG ELISA Assay Kit is manufactured in Germany by Generic Assays. This assay is a module based Enzyme Immunoassay for the confirmation of positive IgG antibodies against SARS coronavirus 2 (SARS-CoV-2) in the first screening. The Anti-SARS-CoV-2 (S1, S2, N) IgG ELISA Assay Kit determines the specificity of antibodies against the main immunodominant antigens (Spike Glycoprotein 1, Spike Glycoprotein 2, Nucleocapsid) of SARS-CoV-2 in human serum or plasma. This test kit consists of modules separately coated with the major antigens of the virus as seen in the illistration below:
Size: 96 wells (24 samples x 4) Incubation Time: 2 hours Sample Type: Serum or Plasma Number Of Tests Per Kit: 24 (22 samples + controls) Sample Size: 50 µl Controls Included
To learn more about the Anti-SARS-CoV-2 (S1, S2, N) IgG ELISA Assay Kit click here*
Check out our entire Coronavirus Series here or contact us with any questions or inquires
*These kits are for research use only and should not be used for diagnostic procedures.
Cells infected with SARS-CoV-2 are only visible to CD8+ T cell after virus proteins have been processed and presented by MHC class I molecules – and only then are the CD8+ T cell able to eradicate the infection. While antibodies against the COVID-19 virus are important to prevent or minimize infection, CD8+ T cells are responsible for clearing the virus from the body. Hence, the identification of peptides being presented by MHC class I is essential to:
Design potent vaccines eliciting a persistent response and
Using MHC class I tetramers to monitor cellular immune responses
Assessments of vaccine induced cellular immunity
immunAware’s MHC class I easYmers allow researchers pursuing novel COVID-19 vaccines to generate tetramers and monitor immune responses. In the current pandemic scenario it is essential not to only focus on a few ALA allotypes; rather it is essential to be able to monitor as many allotypes as possible to ensure a novel vaccine targets a broad range of allotypes. Our portfolio of easYmers cover 34 HLA allotypes (HLA-A,-B,-C) which is further supplemented by HLA molecules available for custom tetramer production, bringing the number of available allotypes up to 81. Thus, our range of allotypes ensures a coverage to a 2% frequency in the caucasian population.
The easYmer reagents can also be used to validate the binding of predicted epitopes to further stratify the selection of potential COVID-19 vaccine targets.