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bioRxiv - the preprint server for biology, operated by Cold Spring Harbor Laboratory, a research and educational institution 
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The SARS-CoV-2 immune response in human milk has not yet been examined, though protecting
Gilbert C FAURE's insight:
at last,
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Brain, Behavior, and Immunity Volume 87, July 2020, Pages 182-183 The role of IgA in COVID-19 Author links open overlay panel Show more View Abstract © 2020 Elsevier Inc. All rights reserved.
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Summary We identified types of immune cells that contribute to clearing COVID‐19 during the acute phase of the infection in mouse model and human. Our results suggest that both innate and adaptive ...
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Official site of The Week Magazine, offering commentary and analysis of the day's breaking news and current events as well as arts, entertainment, people and gossip, and political cartoons.
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COVID-19 patients with milder cases have more Immunoglobulin A (IgA) antibodies in their mucosa, according to Dartmouth researchers, including engineering professor Margie Ackerman.
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Time: 7:00 AM Symbol: ALT Source: GlobeNewswire News Releases...
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The results of 3 new studies reveal unknown ways until now that COVID-19 spreads, leading scientists to urge the use of face coverings in public. Research from various parts of the world considered three separate factors in each study: low humidity, public restrooms and airborne dust. The implications from all three of these studies? Mask up!
Low Humidity A study just published in Transboundary and Emerging Diseases confirms an earlier study conducted in the Greater Sydney, Australia area during the early stages of the pandemic that reported a link between low humidity and community spread of COVID-19. The new research led by Dr. Michael Ward in the Sydney School of Veterinary Science adds to the growing body of evidence that low humidity is a key factor in the spread of the Coronavirus. The scientists estimated that for a 1% decrease in relative humidity, COVID-19 cases increase by 7 to 8%. The same link was not found in other weather patterns such as rainfall, temperature or wind. According to Ward, dry air favors the spread of the virus: “”When the humidity is lower, the air is drier and it makes the aerosols smaller,” he said, adding that aerosols are smaller than droplets. “When you sneeze and cough those smaller infectious aerosols can stay suspended in the air for longer. That increases the exposure for other people. When the air is humid and the aerosols are larger and heavier, they fall and hit surfaces quicker.” These findings add to a growing body of research that recommends wearing a mask.
Public Restrooms A second study conducted by Chinese researchers from Yangzhou University reported that flushing a public restroom toilet or urinal can release clouds of virus-laden aerosols that can be inhaled, posing a serious public health challenge. The scientists simulated and tracked virus-laden particle movements when toilets and urinals were flushed. They discovered that flushing involves an interaction between gas and liquid, resulting in a large spread of aerosol particles. The disturbing results revealed that the trajectory of the particles ejected from flushing showed that more than 57% of the particles traveled away from the urinal. The researchers further point out that when men use urinals in a public restroom, these tiny particles can reach their thigh within 5.5 seconds when compared to the toilet flush, which takes 35 seconds to reach slightly higher. “From our work, it can be inferred that urnial flushing indeed promotes the spread of bacteria and viruses,” said Xiang-Dong Liu, one of the study’s authors. “Wearing a mask should be mandatory within public restrooms during the pandemic, and anti-diffusion improvements are urgently needed to prevent the spread of COVID-19.”
Airborne Dust A third study from the University of California, Davis and the Icahn School of Medicine at Mt. Sinai reported that influenza viruses can spread through the air on dust, fibers and other microscopic particles. Until now, scientists assumed airborne transmission occurred mainly due to respiratory droplets by coughing, sneezing or talking. The scientists examined whether tiny, non-respiratory particles could carry influenza between guinea pigs. Using an automated particle sizer to count airborne particles, they found that uninfected guinea pigs give off spikes of up to 1,000 particles per second as they move around the cage. Particles given off by the animals’ breathing were at a constant but lower rate. Immune guinea pigs with influenza virus painted on their fur could transmit the virus through the air to other, susceptible guinea pigs, showing that the virus did not have to come directly from the respiratory tract to be infectious. Next the researchers tested whether microscopic fibers from an inanimate object could carry infectious viruses. They treated paper facial tissues with influenza virus, let them dry out and then crumpled them in front of the automated particle sizer. Crumpling the tissues released up to 900 particles per second in a size range that could be inhaled. They were also able to infect cells from these particles released from the virus-contaminated paper tissues. According to the researchers, the surprising findings that dust can spread viruses have obvious implications for Coronavirus transmission and use of masks for protection. Plus, they said, it opens up an entire new field of investigation on how outbreaks are interpreted.
Original studies available in these sites: https://doi.org/10.1063/5.0021450 https://doi.org/10.1038/s41467-020-17888-w https://doi.org/10.1111/tbed.13766 Via Juan Lama
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IgA secreting plasma cells in the lamina propria are shown to be an important source of iNOS and TNF required to maintain the homeostatic balance between intestinal microbes and the immune system. The gut contains a vast number of bacteria that are essential for the health of the organism, but it is also a rich source of lymphocytes that exist to eliminate infections. How do lymphocytes restrain themselves from attacking beneficial bacteria, yet maintain their ability to respond to true pathogens? Fritz et al. show that as B cells differentiate into plasma cells in the gut, they adopt a phenotype reminiscent of innate immune cells — inflammatory monocytes — while maintaining their ability to produce immunoglobulin. The resulting immunoglobulin-A-secreting plasma cells in the lamina propria are shown to be the main source of the antimicrobial mediators tumour necrosis factor-α and inducible nitric oxide synthase, which are required to maintain the homeostatic balance between intestinal microbes and the immune system. The largest mucosal surface in the body is in the gastrointestinal tract, a location that is heavily colonized by microbes that are normally harmless. A key mechanism required for maintaining a homeostatic balance between this microbial burden and the lymphocytes that densely populate the gastrointestinal tract is the production and transepithelial transport of poly-reactive IgA (ref. 1). Within the mucosal tissues, B cells respond to cytokines, sometimes in the absence of T-cell help, undergo class switch recombination of their immunoglobulin receptor to IgA, and differentiate to become plasma cells2. However, IgA-secreting plasma cells probably have additional attributes that are needed for coping with the tremendous bacterial load in the gastrointestinal tract. Here we report that mouse IgA+ plasma cells also produce the antimicrobial mediators tumour-necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS), and express many molecules that are commonly associated with monocyte/granulocytic cell types. The development of iNOS-producing IgA+ plasma cells can be recapitulated in vitro in the presence of gut stroma, and the acquisition of this multifunctional phenotype in vivo and in vitro relies on microbial co-stimulation. Deletion of TNF-α and iNOS in B-lineage cells resulted in a reduction in IgA production, altered diversification of the gut microbiota and poor clearance of a gut-tropic pathogen. These findings reveal a novel adaptation to maintaining homeostasis in the gut, and extend the repertoire of protective responses exhibited by some B-lineage cells.
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olfactory epithelium and Covid-19 by sciencemag
Gilbert C FAURE's insight:
Abstract:Altered olfactory function is a common symptom of COVID-19, but its etiology is unknown. A key question is whether SARS-CoV-2 (CoV-2) – the causal agent in COVID-19 – affects olfaction directly, by infecting olfactory sensory neurons or their targets in the olfactory bulb, or indirectly, through perturbation of supporting cells. Here we identify cell types in the olfactory epithelium and olfactory bulb that express SARS-CoV-2 cell entry molecules. Bulk sequencing demonstrated that mouse, non-human primate and human olfactory mucosa expresses two key genes involved in CoV-2 entry, ACE2 and TMPRSS2. However, single cell sequencing revealed that ACE2 is expressed in support cells, stem cells, and perivascular cells, rather than in neurons. Immunostaining confirmed these results and revealed pervasive expression of ACE2 protein in dorsally-located olfactory epithelial sustentacular cells and olfactory bulb pericytes in the mouse. These findings suggest that CoV-2 infection of non-neuronal cell types leads to anosmia and related disturbances in odor perception in COVID-19 patients.
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Preventing hot spots of COVID-19 transmission has emerged as a key challenge in the fight against the virus
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Several of the nasal and oral rinses have been found to have a strong ability to neutralise human coronavirus, which suggests that these products may have the potential to reduce the amount of virus spread by people who are Covid-19 positive.
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Two separate studies have documented the persistence of antibodies that target SARS-CoV-2 in hundreds of patients with COVID-19 at least 3 months after symptom onset.Both studies point to the IgG class of antibodies as the longest-lasting antibodies detectable in the blood and saliva of patients ...
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It is of concern that the US$70 billion infant formula industry has been actively
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A key unsolved question in the current coronavirus disease 2019 (COVID-19) pandemic is the duration of acquired immunity. Insights from infections with the four seasonal human coronaviruses might reveal common characteristics applicable to all human coronaviruses. We monitored healthy individuals for more than 35 years and determined that reinfection with the same seasonal coronavirus occurred frequently at 12 months after infection. The durability of immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. Lessons from seasonal coronavirus infections in humans show that reinfections can occur within 12 months of initial infection, coupled with changes in levels of virus-specific antibodies.
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These findings show that one respiratory virus can block infection with another through
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Since the outbreak of coronavirus disease 2019 (COVID-19), many put their hopes in the rapid development of effective immunizations.As this intervention will n...
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Preclinical studies of a COVID-19 vaccine candidate at the University of Alabama at Birmingham show positive results that appear to distinguish this vaccine candidate from other vaccine candidates that are currently in advanced stages of clinical development, the Maryland-based Altimmune Inc.
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The Coronavirus Disease 2019 pandemic has made deployment of an effective vaccine a global health priority.We evaluated the protective activity of a …...
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medRxiv - The Preprint Server for Health Sciences
Gilbert C FAURE's insight:
AbstractUnderstanding the mechanism that leads to immune dysfunction induced by SARS-CoV2 virus is crucial to develop treatment for severe COVID-19. Here, using single cell RNA-seq, we characterized the peripheral blood mononuclear cells (PBMC) from uninfected controls and COVID-19 patients, and cells in paired broncho-alveolar lavage fluid (BALF). We found a close association of decreased dendritic cells (DC) and increased monocytes resembling myeloid-derived suppressor cells (MDSC) which correlated with lymphopenia and inflammation in the blood of severe COVID-19 patients. Those MDSC-like monocytes were immune-paralyzed. In contrast, monocyte-macrophages in BALFs of COVID-19 patients produced massive amounts of cytokines and chemokines, but secreted little interferons. The frequencies of peripheral T cells and NK cells were significantly decreased in severe COVID-19 patients, especially for innate-like T and various CD8+ T cell subsets, compared to health controls. In contrast, the proportions of various activated CD4+ T cell subsets, including Th1, Th2 and Th17-like cells were increased and more clonally expanded in severe COVID-19 patients. Patients' peripheral T cells showed no sign of exhaustion or augmented cell death, whereas T cells in BALFs produced higher levels of IFNG, TNF, CCL4 and CCL5 etc. Paired TCR tracking indicated abundant recruitment of peripheral T cells to the patients' lung. Together, this study comprehensively depicts how the immune cell landscape is perturbed in severe COVID-19.
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According to the researchers, including those from Ruhr University Bochum in Germany, high quantities of the virus particles, or viral load, can be detected in the oral cavity and throat of some COVID-19 patients.
Gilbert C FAURE's insight:
back from the past, already in use in 1918
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