Phenuiviridae nucleoprotein is the main structural and functional component of the viral cycle, protecting the viral RNA and mediating the essential replication/transcription processes. The nucleoprotein (N) binds the RNA using its globular core and polymerizes through the N-terminus, which is presented as a highly flexible arm, as demonstrated in this article. The nucleoprotein exists in an `open' or a `closed' conformation. In the case of the closed conformation the flexible N-terminal arm folds over the RNA-binding cleft, preventing RNA adsorption. In the open conformation the arm is extended in such a way that both RNA adsorption and N polymerization are possible. In this article, single-crystal X-ray diffraction and small-angle X-ray scattering were used to study the N protein of Toscana virus complexed with a single-chain camelid antibody (VHH) and it is shown that in the presence of the antibody the nucleoprotein is unable to achieve a functional assembly to form a ribonucleoprotein complex.

A new rapid expert consultation from a standing committee of the National Academies of Sciences, Engineering, and Medicine.

Despite a scarce supply, a substantial amount of COVID-19 monoclonal antibody (mAb) treatment courses remain unused, says a new rapid expert consultation from the National Academies of Sciences, Engineering, and Medicine.

SARS-CoV-2, the pandemic virus that causes COVID-19, has mutated endlessly since it burst on the scene in late 2019. An new antibody could help stop it

SARS-CoV-2, the pandemic virus that causes COVID-19, has mutated endlessly since it burst on the scene in late 2019. An new antibody could help stop it

Providing antibody to infants could prove lifesavingToronto, ON – Infants in Canada’s north are facing alarming rates of respiratory infection, but providing an antibody to all infants will prevent hundreds of hospitalizations of babies in the Arctic and save hundreds of thousands of dollars a year. In a paper published today in CMAJ Open, researchers conducted […]

Mathias Uhlén
Dec 1, 2005; 4:1920-1932
Research

Linn Fagerberg
Feb 1, 2014; 13:397-406
Research

The dimeric ectonucleotidase CD73 catalyzes the hydrolysis of AMP at the cell surface to form adenosine, a potent suppressor of the immune response. Blocking CD73 activity in the tumor microenvironment can have a beneficial effect on tumor eradication and is a promising approach for cancer therapy. Biparatopic antibodies binding different regions of CD73 may be a means to antagonize its enzymatic activity. A panel of biparatopic antibodies representing the pairwise combination of 11 parental monoclonal antibodies against CD73 was generated by Fab-arm exchange. Nine variants vastly exceeded the potency of their parental antibodies with ≥90% inhibition of activity and subnanomolar EC50 values. Pairing the Fabs of parents with nonoverlapping epitopes was both sufficient and necessary whereas monovalent antibodies were poor inhibitors. Some parental antibodies yielded potent biparatopics with multiple partners, one of which (TB19) producing the most potent. The structure of the TB19 Fab with CD73 reveals that it blocks alignment of the N- and C-terminal CD73 domains necessary for catalysis. A separate structure of CD73 with a Fab (TB38) which complements TB19 in a particularly potent biparatopic shows its binding to a nonoverlapping site on the CD73 N-terminal domain. Structural modeling demonstrates a TB19/TB38 biparatopic antibody would be unable to bind the CD73 dimer in a bivalent manner, implicating crosslinking of separate CD73 dimers in its mechanism of action. This ability of a biparatopic antibody to both crosslink CD73 dimers and fix them in an inactive conformation thus represents a highly effective mechanism for the inhibition of CD73 activity.

Lipoprotein (a) [Lp(a)] is a risk factor for CVD and a target of therapy, but Lp(a) measurements are not globally standardized. Commercially available assays generally use polyclonal antibodies that detect multiple sites within the kringle (K)IV₂ repeat region of Lp(a) and may lead to inaccurate assessments of plasma levels. With increasing awareness of Lp(a) as a cardiovascular risk factor and the active clinical development of new potential therapeutic approaches, the broad availability of reagents capable of providing isoform independence of Lp(a) measurements is paramount. To address this issue, we generated a murine monoclonal antibody that binds to only one site on apo(a). A BALB/C mouse was immunized with a truncated version of apo(a) that contained eight total KIV repeats, including only one copy of KIV₂. We generated hybridomas, screened them, and successfully produced a KIV₂-independent monoclonal antibody, named LPA-KIV9. Using a variety of truncated apo(a) constructs to map its binding site, we found that LPA-KIV9 binds to KIV₉ without binding to plasminogen. Fine peptide mapping revealed that LPA-KIV9 bound to the sequence ⁴⁰⁷⁶LETPTVV⁴⁰⁸² on KIV₉. In conclusion, the generation of monoclonal antibody LPA-KIV9 may be a useful reagent in basic research studies and in the clinical application of Lp(a) measurements.

For three decades, the LPL–specific monoclonal antibody 5D2 has been used to investigate LPL structure/function and intravascular lipolysis. 5D2 has been used to measure LPL levels, block the triglyceride hydrolase activity of LPL, and prevent the propensity of concentrated LPL preparations to form homodimers. Two early studies on the location of the 5D2 epitope reached conflicting conclusions, but the more convincing report suggested that 5D2 binds to a tryptophan (Trp)-rich loop in the carboxyl terminus of LPL. The same loop had been implicated in lipoprotein binding. Using surface plasmon resonance, we showed that 5D2 binds with high affinity to a synthetic LPL peptide containing the Trp-rich loop of human (but not mouse) LPL. We also showed, by both fluorescence and UV resonance Raman spectroscopy, that the Trp-rich loop binds lipids. Finally, we used X-ray crystallography to solve the structure of the Trp-rich peptide bound to a 5D2 Fab fragment. The Trp-rich peptide contains a short α-helix, with two Trps projecting into the antigen recognition site. A proline substitution in the α-helix, found in mouse LPL, is expected to interfere with several hydrogen bonds, explaining why 5D2 cannot bind to mouse LPL.

Antibodies play essential roles in both diagnostics and therapeutics. Epitope mapping is essential to understand how an antibody works and to protect intellectual property. Given the millions of antibodies for which epitope information is lacking, there is a need for high-throughput epitope mapping. To address this, we developed a strategy, Antibody binding epitope Mapping (AbMap), by combining a phage displayed peptide library with next generation sequencing. Using AbMap, profiles of the peptides bound by 202 antibodies were determined in a single test, and linear epitopes were identified for >50% of the antibodies. Using spike protein (S1 and S2)-enriched antibodies from the convalescent serum of one COVID-19 patient as the input, both linear and conformational epitopes of spike protein specific antibodies were identified. We defined peptide-binding profile of an antibody as the Binding Capacity (BiC). Conceptually, the BiC could serve as a systematic and functional descriptor of any antibody. Requiring at least one order of magnitude less time and money to map linear epitopes than traditional technologies, AbMap allows for high-throughput epitope mapping and creates many possibilities.

Mutations of p53 protein occur in over half of all cancers, with profound effects on tumor biology. We present the first—to our knowledge—method for noninvasive visualization of p53 in tumor tissue in vivo, using SPECT, in 3 different models of cancer. Methods: Anti-p53 monoclonal antibodies were conjugated to the cell-penetrating transactivator of transcription (TAT) peptide and a metal ion chelator and then radiolabeled with ¹¹¹In to allow SPECT imaging. ¹¹¹In-anti-p53-TAT conjugates were retained longer in cells overexpressing p53-specific than non–p53-specific ¹¹¹In-mIgG (mouse IgG from murine plasma)-TAT controls, but not in null p53 cells. Results: In vivo SPECT imaging showed enhanced uptake of ¹¹¹In-anti-p53-TAT, versus ¹¹¹In-mIgG-TAT, in high-expression p53^R175H and medium-expression wild-type p53 but not in null p53 tumor xenografts. The results were confirmed in mice bearing genetically engineered KPC mouse–derived pancreatic ductal adenocarcinoma tumors. Imaging with ¹¹¹In-anti-p53-TAT was possible in KPC mice bearing spontaneous p53^R172H pancreatic ductal adenocarcinoma tumors. Conclusion: We demonstrate the feasibility of noninvasive in vivo molecular imaging of p53 in tumor tissue using a radiolabeled TAT-modified monoclonal antibody.

The Drosophila embryonic central nervous system has been used for decades as a model for understanding the genetic regulation of axon guidance and other aspects of neural development. Foundational studies using antibody staining to examine the embryonic ventral nerve cord in wild-type and mutant animals led to the discovery of evolutionarily conserved genes that regulate fundamental aspects of axon guidance, including midline crossing of axons. The development of the regular, segmentally repeating structure of axon pathways in the ventral nerve cord can illustrate basic principles of axon guidance to beginning students and can also be used by expert researchers to characterize new mutants, detect genetic interactions between known genes, and precisely quantify variations in gene function in engineered mutant lines. Here, we describe a protocol for collecting and fixing Drosophila embryos and visualizing axon pathways in the embryonic ventral nerve cord using immunofluorescence or immunohistochemical staining methods. As embryogenesis in Drosophila takes ~24 h to complete, a 1-d collection yields embryos representing all stages of development from newly fertilized through ready-to-hatch larvae, allowing investigation of multiple developmental events within a single batch of collected embryos. The methods described in this protocol should be accessible to introductory laboratory courses as well as seasoned investigators in established research laboratories.

Respiratory syncytial virus (RSV) is a major global pathogen, causing lower respiratory tract disease in at-risk populations including young children. Antibodies form a crucial layer of protection from RSV disease, particularly in immunologically naïve infants. Such antibodies are derived from the mother via transplacental transfer and breast milk, but may be particularly low in high-risk infants such as those born preterm. Maternally derived antibodies can now be supplemented by the administration of anti-RSV monoclonal antibodies, while a rising wave of maternal and paediatric vaccine strategies are approaching. The implementation of these prophylactics may profoundly decrease the healthcare burden of RSV. In this article, we review the role of antibody-mediated immunity in protecting children from RSV. We focus on maternally derived antibodies as the main source of protection against RSV and study factors that influence the scale of this transfer. The role of passive and active prophylactic approaches in protecting infants against RSV are discussed and knowledge gaps in our understanding of antibody-mediated protection against RSV are identified.

Recurrent pregnancy loss occurs in women who have lost two or more pregnancies for unknown reasons. Dr. Kenji Tanimura and his team at Kobe University

medlinkHIV/medlink patients with pulmonary tuberculosis had broader and more potent HIV antibodies compared to those without suspected or documented

"National Institute of Virology, Pune, has successfully developed the 1st indigenous anti-SARS-CoV-2 human IgG ELISA test kit for antibody detection of COVID-19," the minister said in one of a series of tweets. "This robust test will play a critical role in surveillance of proportion of population exposed to SARSCoV2 infection," he said.

Antibodies are widely used as cancer therapeutics, but their current use is limited by the low number of antigens restricted to cancer cells. A receptor tyrosine kinase, receptor tyrosine kinase-like orphan receptor 2 (ROR2), is normally expressed only during embryogenesis and is tightly down-regulated in postnatal healthy tissues. However, it is up-regulated in a diverse set of hematologic and solid malignancies, thus ROR2 represents a candidate antigen for antibody-based cancer therapy. Here we describe the affinity maturation and humanization of a rabbit mAb that binds human and mouse ROR2 but not human ROR1 or other human cell-surface antigens. Co-crystallization of the parental rabbit mAb in complex with the human ROR2 kringle domain (hROR2-Kr) guided affinity maturation by heavy-chain complementarity-determining region 3 (HCDR3)-focused mutagenesis and selection. The affinity-matured rabbit mAb was then humanized by complementarity-determining region (CDR) grafting and framework fine tuning and again co-crystallized with hROR2-Kr. We show that the affinity-matured and humanized mAb retains strong affinity and specificity to ROR2 and, following conversion to a T cell–engaging bispecific antibody, has potent cytotoxicity toward ROR2-expressing cells. We anticipate that this humanized affinity-matured mAb will find application for antibody-based cancer therapy of ROR2-expressing neoplasms.

As hundreds of test kits claim to offer accurate results on previous Covid-19 infection, scientists around the world are working hard to assess their accuracy

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At the Erasmus University Medical Centre in Rotterdam, Marion Koopmans and a team of scientists are going throught the laborious process of verifying antibody tests for Covid-19. Over the last two months, dozens of prospective tests have hit the market, and with many governments wanting to feed the results of large-scale testing into their decisions whether to end lockdowns, biological tests have rarely carried such weight.

Most of the tests are enthusiastically marketed, boasting of their ability to accurately detect whether someone has previously been infected with the Sars-CoV-2 virus. The painstaking job of proving whether the tests do what they say has fallen to a worldwide network of 12 independent centres, of which Koopmans’s team is one.

Jerusalem, May 05: Israeli Defence Minister Naftali Bennett has said that scientists at the country's main biological research institute have made a "significant breakthrough" in developing an antibody to the novel coronavirus, as the researchers wrapped up the development phase and moved

Structures of the immunodominant protein P46 from M. hyopneumoniae has been determined by X-ray crystallography and it is shown that P46 can bind a diversity of oligosaccharides, particularly xylose, which exhibits a very high affinity for this protein. Structures of a monoclonal antibody, both alone and in complex with P46, that was raised against M. hyopnemoniae cells and specifically recognizes P46 are also reported.

Apoptosis is a crucial process by which multicellular organisms control tissue growth, removal and inflammation. Disruption of the normal apoptotic function is often observed in cancer, where cell death is avoided by the overexpression of anti-apoptotic proteins of the Bcl-2 (B-cell lymphoma 2) family, including Mcl-1 (myeloid cell leukaemia 1). This makes Mcl-1 a potential target for drug therapy, through which normal apoptosis may be restored by inhibiting the protective function of Mcl-1. Here, the discovery and biophysical properties of an anti-Mcl-1 antibody fragment are described and the utility of both the scFv and Fab are demonstrated in generating an Mcl-1 crystal system amenable to iterative structure-guided drug design.

Mycoplasma hyopneumoniae is a prokaryotic pathogen that colonizes the respiratory ciliated epithelial cells in swine. Infected animals suffer respiratory lesions, causing major economic losses in the porcine industry. Characterization of the immunodominant membrane-associated proteins from M. hyopneumoniae may be instrumental in the development of new therapeutic approaches. Here, the crystal structure of P46, one of the main surface-antigen proteins, from M. hyopneumoniae is presented and shows N- and C-terminal α/β domains connected by a hinge. The structures solved in this work include a ligand-free open form of P46 (3.1 Å resolution) and two ligand-bound structures of P46 with maltose (2.5 Å resolution) and xylose (3.5 Å resolution) in open and closed conformations, respectively. The ligand-binding site is buried in the cleft between the domains at the hinge region. The two domains of P46 can rotate with respect to each other, giving open or closed alternative conformations. In agreement with this structural information, sequence analyses show similarities to substrate-binding members of the ABC transporter superfamily, with P46 facing the extracellular side as a functional subunit. In the structure with xylose, P46 was also bound to a high-affinity (Kd = 29 nM) Fab fragment from a monoclonal antibody, allowing the characterization of a structural epitope in P46 that exclusively involves residues from the C-terminal domain. The Fab structure in the complex with P46 shows only small conformational rearrangements in the six complementarity-determining regions (CDRs) with respect to the unbound Fab (the structure of which is also determined in this work at 1.95 Å resolution). The structural information that is now available should contribute to a better understanding of sugar nutrient intake by M. hyopneumoniae. This information will also allow the design of protocols and strategies for the generation of new vaccines against this important swine pathogen.

Source: Streetwise Reports   05/06/2020

Testing has been an Achilles heel of the coronavirus pandemic, but ProMIS Neurosciences Inc. (PMN:TSX; ARFXF:OTCQB) has partnered with Dr. Hans Frykman and the BC Neuroimmunology Lab to use its unique technology to create a more accurate antibody test for SARS-CoV-2, the virus that causes Covid-19.

Two main types of tests exist for Covid-19: one that detects the presence of the virus that causes Covid-19, which indicates a person has an active infection, and another that detects antibodies, showing that a person has been exposed to the virus.

The first test that was developed, a test for the presence of the virus, is used mainly to confirm diagnosis of Covid-19 in people who are showing symptoms such as a fever, a dry, persistent cough, difficulty breathing, a sense of restriction in the chest. "They are typical signs of Covid-19, but we would want to know if these are signs of the common flu or a bad cold or Covid-19. We know that Covid can progress really significantly very quickly, especially in individuals with underlying conditions," ProMIS CEO Dr. Elliot Goldstein told Streetwise Reports. "The number of tests is limited, but it's not actually the tests themselves but the reagents and systems you need to run the test that are in short supply."

"Anytime you conduct a test for the virus and get a negative response, the test indicates only that on that day at that time, the person does not have the virus. The person could have had Covid and recovered, or might have had an asymptomatic or very mild case. Or that person could get the virus tomorrow or in three days," Dr. Goldstein explained. "At any point in time the virus test helps indicate the prevalence of the virus—how many people are actually infected—if you test broadly, and at the time you do it, you can determine whether an individual is currently infected or not."

The second type of test, called serological tests or assays, is also known as an antibody test. "When a person is recovering from a viral infection, the immune system makes antibodies—also called immunoglobulins—that are specific to the virus. They neutralize the virus and help clear it out; that's part of the mechanism of why you get better," Dr. Goldstein explained.

One way to see if a person has had Covid is to test for antibodies. "A positive test means you've been exposed to the virus because, in the absence of a vaccine, that's the only way you would have the antibodies. While it's not 100% certain that antibodies neutralize the virus, based on experience with other coronaviruses, it is likely," Dr. Goldstein said. Having the virus neutralized should offer at least some protection against future re-infections.

People who have had positive virus tests know that they have Covid or had Covid and recovered, but many people are asymptomatic or may have had what felt like a light cold, and they want to know if they are at risk, or if they have some protection against the disease. "This is really important for frontline healthcare workers, people working 8-10 hours a day in intensive care or the emergency room with patients known to be very sick with Covid-19; even with protective equipment, they have significant exposure to the virus," Dr. Goldstein explained. "If someone has been through the disease and has natural antibodies, they can't infect someone else. What you want to know on an individual level is am I safe from infection and am I safe for other people."

Generally, antibody testing is a fairly common procedure, Dr. Goldstein explained. When you spin blood in a centrifuge, it separates into three parts: red blood cells, plasma and serum. Serum is where you find antibodies. "ELISA (enzyme-linked immunosorbent assay) is a standard test that looks for antibodies, but it is not specific enough for the Covid-19 virus."

The challenge is there are multiple coronaviruses. "Four different coronaviruses are responsible for the common cold, and then there are others like SARS and MERS. They all have the same sort of halo or corona of protein around the outside of it," Dr. Goldstein said. "They look like the old naval mines used in war. The whole family of coronaviruses look like that. The amino acid sequences of different coronaviruses are not identical but very similar; they share a lot of common structures. There are only really small differences and you can't really pick them up using the usual physical methods."

Studies have shown that up to 90% of individuals in Western countries have been exposed to one or more of the common cold coronaviruses and have antibodies against them. "They look very similar to the coronavirus causing Covid-19. So in Covid-19 antibody tests, the most important thing is it has to be highly specific for the Covid-19 antibodies and doesn't test positive when it identifies a common cold antibody. That is a false positive," said Dr. Goldstein. "It's actually much safer not to have a test that has a lot of false positives because you could base a behavioral decision on faulty information."

Dr. Goldstein cited an example. "If you are testing 1,000 people and there is a 90% prevalence for the cold virus, that means around 900 people have antibodies to the common cold. If the prevalence of the Covid-19 virus is 2%, roughly 20 of the 1,000 would have antibodies to the Covid-19 virus. Let's say the serology test has 95% specificity. That means five times out of 100, it will give a false positive, indicating the presence of Covid-19 antibodies when it is really picking up antibodies against the cold virus. What this means is 5% of 900, or 45 people, will test positive for Covid when they have not had it, and are making decisions based on incorrect information. The consequences of being wrong are dramatic and highlight the need for a very good, high-quality serological test."

How does this relate to Alzheimer's and other neurological diseases that are ProMIS' core competency? "In Alzheimer's, ALS, frontotemporal dementia, Parkinson's disease and other neurological disease, we've been able to use our proprietary, unique technology to identify sites on misfolded proteins that are driving these diseases. Our core technology is the capability to understand what's special about the bad proteins that are causing these diseases and then we can make antibodies highly selective against them. Our technology allows us to identify a region, an epitopes target, which is a series of four to six amino acids where the protein has misfolded. Not only do we know where this target site is located, importantly we also determine the shape (conformation) of this site. Proteins like amyloid and alpha synuclein and TDP 43 misfold and when these proteins misfold they become toxic, they kill neurons, resulting in disease," Dr. Goldstein explained.

ProMIS has transferred that thinking to the virus causing Covid-19. "The corona is composed of the spiky protein. Remember, we want to be able to distinguish between the coronavirus causing the common cold and the coronavirus causing Covid-19," Dr. Goldstein said. "If we can distinguish between the two, we can have an antibody test that's specific for Covid-19. We are looking at a region of the virus called the receptor binding domain, the RBD, that is part of the spike protein and how it attaches to cells. We have a core competency that allows us to identify sites, and not just the location of the sites, but the shape of the sites on complex protein molecules. That allows us then to use that knowledge to create either antibodies or to create serum tests, or even quite frankly, we can use those targets to create vaccines."

Using ProMIS' proprietary technology, the company has been able to "identify a site that we believe is only present on the Covid-19 virus and not on other coronaviruses. We are now initiating the synthesis of several different forms of that site; it's a small area," Dr. Goldstein stated. "That would then transfer to Dr. Hans Frykman's lab at University of British Columbia, a world-class serology lab. Then we will see if the targets we've identified are specific and selective antibodies against Covid-19."

When you test the serum of an individual, if they've been exposed to the virus and have the antibodies, "those antibodies should bind selectively and specifically to the target. So if the antibodies from the patient's serum are binding to the target site, we know it's a Covid-19 virus because that site is only visible in that shape on the Covid-19 virus and not the others. For the validation of our test, only in patients known to have had Covid-19 should we see binding of antibodies against Covid-19 to our target. The second validation is based on testing in serum from subjects known to have never been exposed to Covid-19 virus—such subjects have antibodies only from cold or other coronaviruses, and therefore the antibody test should be negative; there should be no binding. So we should only see binding in serum from a patient known to have recovered from COVID-19, and we should not see binding in serum from an individual known not to have been exposed to COVID-19," Dr. Goldstein explained.

"Our technology basically allows us to zero in with sniper-like precision on the structure of a protein and understand it, not only the structure overall but the shape of the regions on that protein and then that allows us to identify what is specific to that protein, in this case the spiky protein on the virus causing COVID-19," said Dr. Goldstein.

ProMIS expects to have initial results in June.

Disclosure:
1) Patrice Fusillo compiled this article for Streetwise Reports LLC and provides services to Streetwise Reports as an employee. She or members of her household own securities of the following companies mentioned in the article: None. She or members of her household are paid by the following companies mentioned in this article: None.
2) The following companies mentioned in this article are billboard sponsors of Streetwise Reports: ProMIS Neurosciences. Click here for important disclosures about sponsor fees.
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5) From time to time, Streetwise Reports LLC and its directors, officers, employees or members of their families, as well as persons interviewed for articles and interviews on the site, may have a long or short position in securities mentioned. Directors, officers, employees or members of their immediate families are prohibited from making purchases and/or sales of those securities in the open market or otherwise from the time of the interview or the decision to write an article until three business days after the publication of the interview or article. The foregoing prohibition does not apply to articles that in substance only restate previously published company releases. As of the date of this article, officers and/or employees of Streetwise Reports LLC (including members of their household) own securities of ProMIS, a company mentioned in this article.
6) This article does not constitute medical advice. Officers, employees and contributors to Streetwise Reports are not licensed medical professionals. Readers should always contact their healthcare professionals for medical advice.

( Companies Mentioned: PMN:TSX; ARFXF:OTCQB, )

A new rapid expert consultation from a standing committee of the National Academies of Sciences, Engineering, and Medicine.

Phlebotomists process specimens of people getting tested for coronavirus antibodies in Spring Valley. ; Credit: Yana Paskova/Getty Images

As of Tuesday afternoon, L.A. County has at least 1,314 deaths and 27,836 confirmed cases of coronavirus.

New confirmed infections per day in the U.S. exceed 20,000, and deaths per day are well over 1,000,000 according to figures from Johns Hopkins University. And public health officials warn that the failure to flatten the curve and drive down the infection rate in places could lead to many more deaths — perhaps tens of thousands — as people are allowed to venture out and businesses reopen. From the marbled halls of Italy to the wheat fields of Kansas, health authorities are increasingly warning that the question isn’t whether a second wave of coronavirus infections and deaths will hit, but when — and how badly. President Donald Trump said his COVID-19 task force would keep working but focus more on rebooting the economy. According to the Orange County Register, more OC beaches received approval to open with limited hours.

Today on AirTalk, we get the latest on COVID-19. Do you have questions for our infectious disease specialist? Join the conversation by calling 866-893-5722. 

With files from LAist and the Associated Press 

Guest: 

Peter Chin-Hong, M.D., infectious disease specialist and professor of medicine at the UCSF Medical Center; he tweets @PCH_SF

This content is from Southern California Public Radio. View the original story at SCPR.org.

Deputy Chief Patricia Cassidy of the Jersey City Police Department has blood drawn to test for coronavirus antibodies in Jersey City, N.J., on Monday.; Credit: Seth Wenig/AP

The Food and Drug Administration is stiffening its rules to counteract what some have called a Wild West of antibody testing for the coronavirus.

These tests are designed to identify people who have been previously exposed to the virus. The FDA said more than 250 developers have been bringing products to the market in the past few weeks.

In a rush to make antibody tests available as quickly as possible, the FDA had set a low standard for these tests. Manufacturers were supposed to submit their own information about the accuracy of their wares, but the agency had no standards for what would be acceptable. Companies weren't allowed to claim the tests were authorized by the FDA, under initial guidance issued in mid-March.

Now the FDA is telling manufacturers that if they want their tests to remain on the market, they must meet minimum quality standards and submit a request for emergency use authorization, a temporary route to market for unapproved products when others aren't available. The EUA involves a lower standard than the usual FDA clearance or approval.

The FDA said 12 manufacturers have already opted to request EUA's for their products. More than 100 other producers have been talking to the agency about using this process, said FDA Commissioner Stephen Hahn. He spoke on a press call Monday. Companies have 10 days to submit that request.

"Our expectation is that those who can't [meet the new standard] will withdraw their products from the market and we will be working with them to help them do that," he said.

These tests are now so widespread that people can order them from lab giants Quest or LabCorp. The tests can cost more than $100. Though the FDA's original guidance calls for these tests to be run by a certified lab, the kits themselves are simple to use and have been readily available.

Despite the enthusiasm surrounding these tests, they have substantial limitations. Though people who test positive for antibodies have in most cases been exposed to the coronavirus, scientists don't know whether that means those people are actually immune from the coronavirus, and if so for how long.

"Whether this is the ticket for someone to go back to work [based solely on an antibody test result], my opinion on that would be no," Hahn said.

The tests may be more useful when combined with information from a standard coronavirus diagnostic test, or in someone who has symptoms, or if the results have been confirmed with a different antibody test. That "would dramatically increase the accuracy of those tests," said Jeffrey Shuren, director of the FDA's Center for Devices and Radiological Health

Antibodies are a potentially valuable research tool, and can be used to determine the prevalence of a disease in a population. In that circumstance, individual false results are less important. New York State used antibody tests to determine that about 20 percent of people in New York City have already been exposed to the coronavirus.

In California, researchers have attempted to measure the prevalence of the coronavirus in Los Angeles County and Santa Clara County in the Bay Area. Those unpublished results have garnered criticism because even a test that's more than 99 percent accurate can produce many false positive results when used to survey hundreds or thousands of people.

In the face of this criticism, the authors of the Santa Clara study have posted revised results acknowledging the high degree of uncertainty in their findings. Those findings haven't been peer-reviewed.

The emergency use authorization is only valid during the time of the national emergency. "Once the national emergency ends, the EUA authorizations end as well," Shuren said. Companies that want to keep marketing these tests will need to get them approved through the regular, more stringent FDA process.

FDA officials say they will continue to crack down on companies that falsely claim their tests are approved by the FDA, or that market them for home use, which isn't currently allowed.

You can contact NPR Science Correspondent Richard Harris at rharris@npr.org.

This content is from Southern California Public Radio. View the original story at SCPR.org.

Source: Streetwise Reports   05/06/2020

Testing has been an Achilles heel of the coronavirus pandemic, but ProMIS Neurosciences Inc. (PMN:TSX; ARFXF:OTCQB) has partnered with Dr. Hans Frykman and the BC Neuroimmunology Lab to use its unique technology to create a more accurate antibody test for SARS-CoV-2, the virus that causes Covid-19.

Two main types of tests exist for Covid-19: one that detects the presence of the virus that causes Covid-19, which indicates a person has an active infection, and another that detects antibodies, showing that a person has been exposed to the virus.

The first test that was developed, a test for the presence of the virus, is used mainly to confirm diagnosis of Covid-19 in people who are showing symptoms such as a fever, a dry, persistent cough, difficulty breathing, a sense of restriction in the chest. "They are typical signs of Covid-19, but we would want to know if these are signs of the common flu or a bad cold or Covid-19. We know that Covid can progress really significantly very quickly, especially in individuals with underlying conditions," ProMIS CEO Dr. Elliot Goldstein told Streetwise Reports. "The number of tests is limited, but it's not actually the tests themselves but the reagents and systems you need to run the test that are in short supply."

"Anytime you conduct a test for the virus and get a negative response, the test indicates only that on that day at that time, the person does not have the virus. The person could have had Covid and recovered, or might have had an asymptomatic or very mild case. Or that person could get the virus tomorrow or in three days," Dr. Goldstein explained. "At any point in time the virus test helps indicate the prevalence of the virus—how many people are actually infected—if you test broadly, and at the time you do it, you can determine whether an individual is currently infected or not."

The second type of test, called serological tests or assays, is also known as an antibody test. "When a person is recovering from a viral infection, the immune system makes antibodies—also called immunoglobulins—that are specific to the virus. They neutralize the virus and help clear it out; that's part of the mechanism of why you get better," Dr. Goldstein explained.

One way to see if a person has had Covid is to test for antibodies. "A positive test means you've been exposed to the virus because, in the absence of a vaccine, that's the only way you would have the antibodies. While it's not 100% certain that antibodies neutralize the virus, based on experience with other coronaviruses, it is likely," Dr. Goldstein said. Having the virus neutralized should offer at least some protection against future re-infections.

People who have had positive virus tests know that they have Covid or had Covid and recovered, but many people are asymptomatic or may have had what felt like a light cold, and they want to know if they are at risk, or if they have some protection against the disease. "This is really important for frontline healthcare workers, people working 8-10 hours a day in intensive care or the emergency room with patients known to be very sick with Covid-19; even with protective equipment, they have significant exposure to the virus," Dr. Goldstein explained. "If someone has been through the disease and has natural antibodies, they can't infect someone else. What you want to know on an individual level is am I safe from infection and am I safe for other people."

Generally, antibody testing is a fairly common procedure, Dr. Goldstein explained. When you spin blood in a centrifuge, it separates into three parts: red blood cells, plasma and serum. Serum is where you find antibodies. "ELISA (enzyme-linked immunosorbent assay) is a standard test that looks for antibodies, but it is not specific enough for the Covid-19 virus."

The challenge is there are multiple coronaviruses. "Four different coronaviruses are responsible for the common cold, and then there are others like SARS and MERS. They all have the same sort of halo or corona of protein around the outside of it," Dr. Goldstein said. "They look like the old naval mines used in war. The whole family of coronaviruses look like that. The amino acid sequences of different coronaviruses are not identical but very similar; they share a lot of common structures. There are only really small differences and you can't really pick them up using the usual physical methods."

Studies have shown that up to 90% of individuals in Western countries have been exposed to one or more of the common cold coronaviruses and have antibodies against them. "They look very similar to the coronavirus causing Covid-19. So in Covid-19 antibody tests, the most important thing is it has to be highly specific for the Covid-19 antibodies and doesn't test positive when it identifies a common cold antibody. That is a false positive," said Dr. Goldstein. "It's actually much safer not to have a test that has a lot of false positives because you could base a behavioral decision on faulty information."

Dr. Goldstein cited an example. "If you are testing 1,000 people and there is a 90% prevalence for the cold virus, that means around 900 people have antibodies to the common cold. If the prevalence of the Covid-19 virus is 2%, roughly 20 of the 1,000 would have antibodies to the Covid-19 virus. Let's say the serology test has 95% specificity. That means five times out of 100, it will give a false positive, indicating the presence of Covid-19 antibodies when it is really picking up antibodies against the cold virus. What this means is 5% of 900, or 45 people, will test positive for Covid when they have not had it, and are making decisions based on incorrect information. The consequences of being wrong are dramatic and highlight the need for a very good, high-quality serological test."

How does this relate to Alzheimer's and other neurological diseases that are ProMIS' core competency? "In Alzheimer's, ALS, frontotemporal dementia, Parkinson's disease and other neurological disease, we've been able to use our proprietary, unique technology to identify sites on misfolded proteins that are driving these diseases. Our core technology is the capability to understand what's special about the bad proteins that are causing these diseases and then we can make antibodies highly selective against them. Our technology allows us to identify a region, an epitopes target, which is a series of four to six amino acids where the protein has misfolded. Not only do we know where this target site is located, importantly we also determine the shape (conformation) of this site. Proteins like amyloid and alpha synuclein and TDP 43 misfold and when these proteins misfold they become toxic, they kill neurons, resulting in disease," Dr. Goldstein explained.

ProMIS has transferred that thinking to the virus causing Covid-19. "The corona is composed of the spiky protein. Remember, we want to be able to distinguish between the coronavirus causing the common cold and the coronavirus causing Covid-19," Dr. Goldstein said. "If we can distinguish between the two, we can have an antibody test that's specific for Covid-19. We are looking at a region of the virus called the receptor binding domain, the RBD, that is part of the spike protein and how it attaches to cells. We have a core competency that allows us to identify sites, and not just the location of the sites, but the shape of the sites on complex protein molecules. That allows us then to use that knowledge to create either antibodies or to create serum tests, or even quite frankly, we can use those targets to create vaccines."

Using ProMIS' proprietary technology, the company has been able to "identify a site that we believe is only present on the Covid-19 virus and not on other coronaviruses. We are now initiating the synthesis of several different forms of that site; it's a small area," Dr. Goldstein stated. "That would then transfer to Dr. Hans Frykman's lab at University of British Columbia, a world-class serology lab. Then we will see if the targets we've identified are specific and selective antibodies against Covid-19."

When you test the serum of an individual, if they've been exposed to the virus and have the antibodies, "those antibodies should bind selectively and specifically to the target. So if the antibodies from the patient's serum are binding to the target site, we know it's a Covid-19 virus because that site is only visible in that shape on the Covid-19 virus and not the others. For the validation of our test, only in patients known to have had Covid-19 should we see binding of antibodies against Covid-19 to our target. The second validation is based on testing in serum from subjects known to have never been exposed to Covid-19 virus—such subjects have antibodies only from cold or other coronaviruses, and therefore the antibody test should be negative; there should be no binding. So we should only see binding in serum from a patient known to have recovered from COVID-19, and we should not see binding in serum from an individual known not to have been exposed to COVID-19," Dr. Goldstein explained.

"Our technology basically allows us to zero in with sniper-like precision on the structure of a protein and understand it, not only the structure overall but the shape of the regions on that protein and then that allows us to identify what is specific to that protein, in this case the spiky protein on the virus causing COVID-19," said Dr. Goldstein.

ProMIS expects to have initial results in June.

Disclosure:
1) Patrice Fusillo compiled this article for Streetwise Reports LLC and provides services to Streetwise Reports as an employee. She or members of her household own securities of the following companies mentioned in the article: None. She or members of her household are paid by the following companies mentioned in this article: None.
2) The following companies mentioned in this article are billboard sponsors of Streetwise Reports: ProMIS Neurosciences. Click here for important disclosures about sponsor fees.
3) Comments and opinions expressed are those of the specific experts and not of Streetwise Reports or its officers. The information provided above is for informational purposes only and is not a recommendation to buy or sell any security.
4) The article does not constitute investment advice. Each reader is encouraged to consult with his or her individual financial professional and any action a reader takes as a result of information presented here is his or her own responsibility. By opening this page, each reader accepts and agrees to Streetwise Reports' terms of use and full legal disclaimer. This article is not a solicitation for investment. Streetwise Reports does not render general or specific investment advice and the information on Streetwise Reports should not be considered a recommendation to buy or sell any security. Streetwise Reports does not endorse or recommend the business, products, services or securities of any company mentioned on Streetwise Reports.
5) From time to time, Streetwise Reports LLC and its directors, officers, employees or members of their families, as well as persons interviewed for articles and interviews on the site, may have a long or short position in securities mentioned. Directors, officers, employees or members of their immediate families are prohibited from making purchases and/or sales of those securities in the open market or otherwise from the time of the interview or the decision to write an article until three business days after the publication of the interview or article. The foregoing prohibition does not apply to articles that in substance only restate previously published company releases. As of the date of this article, officers and/or employees of Streetwise Reports LLC (including members of their household) own securities of ProMIS, a company mentioned in this article.
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( Companies Mentioned: PMN:TSX; ARFXF:OTCQB, )

Although the causes of Alzheimer's disease are still unknown, it is clear that the disease commences with progressive amyloid deposition in the brains of affected persons between ten and fifteen years before the emergence of initial clinical symptoms such as memory loss. Researchers have now been able to show that Aducanumab, a human monoclonal antibody, selectively binds brain amyloid plaques, thus enabling microglial cells to remove the plaques. A one-year treatment with the antibody, as part of a phase Ib study, resulted in almost complete clearance of the brain amyloid plaques in the study group patients. The results, which were realized by researchers at UZH together with the biotech company "Biogen" and the UZH spin-off "Neurimmune," have been published in the renowned science journal "Nature."

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Farber Cancer Institute investigators report they have discovered a type of immune antibody that can rapidly evolve to neutralize a wide array of influenza virus strains - including those the body hasn't yet encountered.

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Patients Now Able to Determine If Symptoms Actually Represented a COVID-19 Infection

Aaron Lavinsky/Star Tribune via Getty Images

• Diagnostic or polymerase chain reaction (PCR) tests are currently being used to diagnose patients with COVID-19.
  
  
• Antibody tests allow for more accurate tracking of the spread of the coronavirus. People who test positive for coronavirus antibodies can also donate plasma.
• Antigen testing is not on the market yet, but Massachusetts-based E25Bio is among several companies seeking FDA approval for at-home test kits.
• Visit Business Insider's homepage for more stories.

With new information released all the time, it can be difficult to keep track of how doctors are testing for the coronavirus. 

While identifying and treating infected patients is critical, some tests add to our greater understanding of the pandemic's size, impact, and direction. Here is a breakdown of the differences between diagnostic, antibody, and antigen testing.

See the rest of the story at Business Insider

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The following came in the email: I’m a reporter for **, and am looking for comment on the stats Gov Cuomo just released. Would you be available for a 10-minute phone conversation? Please let me know. Thanks so much, and here’s the info: Here is the relevant part: In New York City, about 21 percent, […]

The invention relates to antibody molecules having specificity for antigenic determinants of human OX40, therapeutic uses of the antibody molecules and methods for producing said antibody molecules.

The present invention relates to fusion proteins comprising an antibody, functional fragment or functional derivative thereof having specific binding affinity to either the extracellular domain of oncofetal fibronectin (ED-B) or at least one of the extracellular domains of oncofetal tenascin fused to a cytokine selected from the group consisting of IL-10, IL15, IL-24 and GM-CSF, functional fragments and functional derivatives thereof. The invention is also directed to the use of at least one of said fusion proteins for the manufacture of a medicament. In particular, the invention concerns the use of said medicament for the treatment of tumors or chronic inflammatory diseases such as atherosclerosis, arthritis and psoriasis.

Plant viral vectors have great potential in rapid production of proteins, but no simple. Here a geminivirus-based system for high-yield and rapid production of oligomeric protein complexes, including virus-like particle (VLP) vaccines and monoclonal antibodies (mAbs) is described. In particular, a single vector that contains two non-competing replicons for transient expression in Nicotiana benthamiana leaves is described. The correct assembly of these subunit proteins into functional oligomeric structures (VLPs or full-size mAb) is also described. This system advances plant transient expression technology by eliminating the need for non-competing viruses, and thus, enhances the realistic commercial application of this technology for producing multiple-subunit protein complexes.

Disclosed herein are antibody-nanoparticle conjugates that include two or more nanoparticles (such as gold, palladium, platinum, silver, copper, nickel, cobalt, iridium, or an alloy of two or more thereof) directly linked to an antibody or fragment thereof through a metal-thiol bond. Methods of making the antibody-nanoparticle conjugates disclosed herein include reacting an arylphosphine-nanoparticle composite with a reduced antibody to produce an antibody-nanoparticle conjugate. Also disclosed herein are methods for detecting a target molecule in a sample that include using an antibody-nanoparticle conjugate (such as the antibody-nanoparticle conjugates described herein) and kits for detecting target molecules utilizing the methods disclosed herein.

The present invention relates to an anti-human α9 integrin antibody. More particularly, the present invention relates to: a monoclonal antibody, a chimeric antibody, a humanized antibody and a human antibody that specifically recognize human α9 integrin; a hybridoma cell that produces the monoclonal antibody; a method for producing the monoclonal antibody; a method for producing the hybridoma cell; a therapeutic agent comprising the anti-human α9 integrin antibody; a diagnostic agent comprising the human α9 integrin antibody; and a method for screening for a compound that inhibits the activity of human α9 integrin.

The present invention relates to a composition comprising at least three primary antibodies or fragments thereof, wherein the at least three antibodies or fragments thereof binds specifically to at least three different proteins, and wherein the at least three different proteins are AMCAR, CK 5/6, and HMWC. Methods for using the composition in diagnosis, prognosis, and assessing efficacy of treatment is further included as well as kits comprising said composition, and optionally, instructions of its use.

Provided is a method of potentiating immunity or preventing or treating an immune-related disease comprising administering an anti-Ang2 antibody or an antigen-binding fragment thereof to a subject in need thereof.

Provided is a method of decreasing blood sugar level or preventing and/or treating a hyperglycemia-related disease, including administering an anti-Ang2 antibody or an antigen-biding fragment thereof to a subject in need thereof.

Provided in some embodiments are antibodies comprising a heavy chain having no native interchain cysteine amino acids, a light chain having no native interchain cysteine amino acids, and having no native interchain disulphide linkages between the heavy chain and the light chain. Also provided in certain embodiments are antibodies comprising a heavy chain having no native interchain cysteine amino acids, a light chain having no native interchain cysteine amino acids, and having no native interchain disulphide linkages between the heavy chain and the light chain where the native interchain cysteine amino acids have been replaced by amino acids having no thiol moiety.

Shares of Quest Diagnostics Inc. (DGX) are rising over 7% in pre-market today, after the company announced the launch of consumer-initiated COVID-19 antibody test through QuestDirect.