An Experimental Peptide Could Block COVID-19https://medicalxpress.com/news/2020-03-experimental-peptide-block-covid-.htmlA team of MIT chemists has designed a drug candidate that they believe may block coronaviruses' ability to enter human cells. The potential drug is a short protein fragment, or peptide, that mimics a protein found on the surface of human cells.The researchers have shown that their new peptide can bind to the viral protein that coronaviruses use to enter human cells, potentially disarming it.
The MIT team reported its initial findings in a preprint posted on bioRxiv, an online preprint server, on March 20. They have sent samples of the peptide to collaborators who plan to carry out tests in human cells.
... Studies of SARS-CoV-2 have also shown that a specific region of the spike protein, known as the receptor binding domain, binds to a receptor called angiotensin-converting enzyme 2 (ACE2). This receptor is found on the surface of many human cells, including those in the lungs. The ACE2 receptor is also the entry point used by the coronavirus that caused the 2002-03 SARS outbreak.
Pentelute's lab, performed computational simulations of the interactions between the ACE2 receptor and the receptor binding domain of the coronavirus spike protein. These simulations revealed the location where the receptor binding domain attaches to the ACE2 receptor—a stretch of the ACE2 protein that forms a structure called an alpha helix.
The MIT team then used peptide synthesis technology that Pentelute's lab has previously developed, to rapidly generate a 23-amino acid peptide with the same sequence as the alpha helix of the ACE2 receptor. ...
One advantage of such a drug is that they are relatively easy to manufacture in large quantities. They also have a larger surface area than small-molecule drugs."Peptides are larger molecules, so they can really grip onto the coronavirus and inhibit entry into cells, whereas if you used a small molecule, it's difficult to block that entire area that the virus is using," Pentelute says. "Antibodies also have a large surface area, so those might also prove useful. Those just take longer to manufacture and discover."
They also synthesized a shorter sequence of only 12 amino acids found in the alpha helix, and then tested both of the peptides using equipment at MIT's Biophysical Instrumentation Facility that can measure how strongly two molecules bind together. They found that the longer peptide showed strong binding to the receptor binding domain of the COVID-19 spike protein, while the shorter one showed negligible binding.
One drawback of peptide drugs is that they typically can't be taken orally, so they would have to be either administered intravenously or injected under the skin. They would also need to be modified so that they can stay in the bloodstream long enough to be effective, which Pentelute's lab is also working on.
G. Zhang et al.
The first-in-class peptide binder to the SARS-CoV-2 spike protein, bioRxiv (2020)
https://www.biorxiv.org/content/10.1101/2020.03.19.999318v1 ---------------------------
COVID-19 patients often infected with other respiratory viruses, preliminary study reportshttps://medicalxpress.com/news/2020-03-covid-patients-infected-respiratory-viruses.htmlAbout one in five people with COVID-19 are also infected with other respiratory viruses, according to a preliminary analysis led by Ian Brown, MD, a clinical associate professor of emergency medicine at the Stanford School of Medicine.
In addition, the analysis found that about one in 10 people who exhibit symptoms of respiratory illness at an emergency department, and who are subsequently diagnosed with a common respiratory virus, are co-infected with the COVID-19 virus.
The findings challenge the assumption that people are unlikely to have COVID-19 if they have another type of viral respiratory disease.
"Currently, if a patient tests positive for a different respiratory virus, we believe that they don't have COVID-19," ... "However, given the co-infection rates we've observed in this sample, that is an incorrect assumption.""Hospitals don't have unlimited access to COVID testing," Brown said . "In some cases, a patient with respiratory symptoms may first be tested for a non-COVID virus. If there is a diagnosis of influenza or rhinovirus, or other respiratory virus, a hospital may discharge the patient without COVID testing, concluding that the alternative diagnosis is the reason for the symptoms."
Higher co-infection rates in COVID19.https://medium.com/@nigam/higher-co-infection-rates-in-covid19-b24965088333 ------------------------------
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