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.." The candidate vaccine mRNA-1273 is a
lipid nanoparticle–encapsulated, nucleoside-modified messenger RNA
(mRNA)–based vaccine that encodes the SARS-CoV-2 spike (S) glycoprotein
stabilized in its prefusion conformation. The S glycoprotein mediates
host cell attachment and is required for viral entry
SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls.
Nature. 2020 Jul 15. doi: 10.1038/s41586-020-2550-z. Online ahead of print.
PMID: 32668444.
Abstract
Memory T cells induced by previous pathogens can shape the
susceptibility to, and clinical severity of, subsequent infections1.
Little is known about the presence of pre-existing memory T cells in
humans with the potential to recognize SARS-CoV-2. Here, we first
studied T cell responses to structural (nucleocapsid protein, NP) and
non-structural (NSP-7 and NSP13 of ORF1) regions of SARS-CoV-2 in
COVID-19 convalescents (n=36). In all of them we demonstrated the
presence of CD4 and CD8 T cells recognizing multiple regions of the NP
protein. We then showed that SARS-recovered patients (n=23) still
possess long-lasting memory T cells reactive to SARS-NP 17 years after
the 2003 outbreak, which displayed robust cross-reactivity to SARS-CoV-2
NP. Surprisingly, we also frequently detected SARS-CoV-2 specific T
cells in individuals with no history of SARS, COVID-19 or contact with
SARS/COVID-19 patients (n=37). SARS-CoV-2 T cells in uninfected donors
exhibited a different pattern of immunodominance, frequently targeting
the ORF-1-coded proteins NSP7 and 13 as well as the NP structural
protein. Epitope characterization of NSP7-specific T cells showed
recognition of protein fragments with low homology to "common cold"
human coronaviruses but conserved amongst animal betacoranaviruses.
Thus, infection with betacoronaviruses induces multispecific and
long-lasting T cell immunity to the structural protein NP. Understanding
how pre-existing NP- and ORF-1-specific T cells present in the general
population impact susceptibility and pathogenesis of SARS-CoV-2
infection is of paramount importance for the management of the current
COVID-19 pandemic.
Potently neutralizing and protective human antibodies against SARS-CoV-2.
Nature. 2020 Jul 15. doi: 10.1038/s41586-020-2548-6.
Online ahead of print. PMID: 32668443The COVID-19 pandemic is a major threat to global health1 for which there are limited medical countermeasures2,3. Moreover, we currently lack a thorough understanding of mechanisms of humoral immunity4. From a larger panel of human monoclonal antibodies (mAbs) targeting the spike (S) glycoprotein5, we identified several that exhibited potent neutralizing activity and fully blocked the receptor-binding domain of S (SRBD) from interacting with human ACE2 (hACE2). Competition-binding, structural, and functional studies allowed clustering of the mAbs into classes recognizing distinct epitopes on the SRBD as well as distinct conformational states of the S trimer. Potent neutralizing mAbs recognizing non-overlapping sites, COV2-2196 and COV2-2130, bound simultaneously to S and synergistically neutralized authentic SARS-CoV-2 virus. In two mouse models of SARS-CoV-2 infection, passive transfer of either COV2-2196 or COV2-2130 alone or a combination of both mAbs protected mice from weight loss and reduced viral burden and inflammation in the lung. In addition, passive transfer of each of two of the most potently ACE2 blocking mAbs (COV2-2196 or COV2-2381) as monotherapy protected rhesus macaques from SARS-CoV-2 infection. These results identify protective epitopes on SRBD and provide a structure-based framework for rational vaccine design and the selection of robust immunotherapeutics.
Online ahead of print. PMID: 32668443The COVID-19 pandemic is a major threat to global health1 for which there are limited medical countermeasures2,3. Moreover, we currently lack a thorough understanding of mechanisms of humoral immunity4. From a larger panel of human monoclonal antibodies (mAbs) targeting the spike (S) glycoprotein5, we identified several that exhibited potent neutralizing activity and fully blocked the receptor-binding domain of S (SRBD) from interacting with human ACE2 (hACE2). Competition-binding, structural, and functional studies allowed clustering of the mAbs into classes recognizing distinct epitopes on the SRBD as well as distinct conformational states of the S trimer. Potent neutralizing mAbs recognizing non-overlapping sites, COV2-2196 and COV2-2130, bound simultaneously to S and synergistically neutralized authentic SARS-CoV-2 virus. In two mouse models of SARS-CoV-2 infection, passive transfer of either COV2-2196 or COV2-2130 alone or a combination of both mAbs protected mice from weight loss and reduced viral burden and inflammation in the lung. In addition, passive transfer of each of two of the most potently ACE2 blocking mAbs (COV2-2196 or COV2-2381) as monotherapy protected rhesus macaques from SARS-CoV-2 infection. These results identify protective epitopes on SRBD and provide a structure-based framework for rational vaccine design and the selection of robust immunotherapeutics.
A perspective on potential antibody-dependent enhancement of SARS-CoV-2.
Nature. 2020 Jul 13. doi: 10.1038/s41586-020-2538-8. Online ahead of print.
PMID: 32659783
Review.The possibility of antibody-dependent enhancement (ADE) of disease is a
general concern for the development of vaccines and antibody therapies
because the mechanisms that underlie antibody protection have the
theoretical potential to amplify viral infections or trigger
immunopathology. Observations relevant to the risks of ADE of disease
require careful review at this critical point in the SARS-CoV-2
pandemic. At present, no clinical findings, immunologic assays or
biomarkers are known to differentiate any severe viral infection from
immune-enhanced disease, whether by antibodies, T cells or intrinsic
host responses. In vitro systems and animal models do not predict the
risk of ADE of disease, in part because protective and potentially
detrimental antibody-mediated mechanisms are the same, and designing
animal models depends on understanding how antiviral host responses may
become harmful in people. The implications of our lack of knowledge are
twofold. First, comprehensive studies are urgently needed to define
clinical correlates of protective immunity against SARS-CoV-2. Second,
since we cannot predict ADE of disease reliably after either vaccination
or treatment with antibodies, regardless of what virus is the causative
agent, it will be essential to depend on careful analysis of safety in
humans as immune interventions for COVID-19 disease move forward.
The Intestinal Microbiome Restricts Alphavirus Infection
and Dissemination through a Bile Acid-Type I IFN Signaling Axis.
Cell. 2020 Jul 8:S0092-8674(20)30806-0. doi: 10.1016/j.cell.2020.06.029. Online ahead of print.
PMID: 32668198
The link between Vitamin D and Covid-19: distinguishing facts from fiction.
J Intern Med. 2020 Jul 11. doi: 10.1111/joim.13158. Online ahead of print.
PMID: 32652766https://doi.org/10.1111/joim.13158
Extrapulmonary manifestations of COVID-19.
Nat Med. 2020 Jul;26(7):1017-1032. doi: 10.1038/s41591-020-0968-3. Epub 2020 Jul 10.
PMID: 32651579
Review. Although COVID-19 is most well known for causing substantial respiratory pathology, it can also result in several extrapulmonary manifestations. These conditions include thrombotic complications, myocardial dysfunction and arrhythmia, acute coronary syndromes, acute kidney injury, gastrointestinal symptoms, hepatocellular injury, hyperglycemia and ketosis, neurologic illnesses, ocular symptoms, and dermatologic complications. Given that ACE2, the entry receptor for the causative coronavirus SARS-CoV-2, is expressed in multiple extrapulmonary tissues, direct viral tissue damage is a plausible mechanism of injury. In addition, endothelial damage and thromboinflammation, dysregulation of immune responses, and maladaptation of ACE2-related pathways might all contribute to these extrapulmonary manifestations of COVID-19. Here we review the extrapulmonary organ-specific pathophysiology, presentations and management considerations for patients with COVID-19 to aid clinicians and scientists in recognizing and monitoring the spectrum of manifestations, and in developing research priorities and therapeutic strategies for all organ systems involved.
Review. Although COVID-19 is most well known for causing substantial respiratory pathology, it can also result in several extrapulmonary manifestations. These conditions include thrombotic complications, myocardial dysfunction and arrhythmia, acute coronary syndromes, acute kidney injury, gastrointestinal symptoms, hepatocellular injury, hyperglycemia and ketosis, neurologic illnesses, ocular symptoms, and dermatologic complications. Given that ACE2, the entry receptor for the causative coronavirus SARS-CoV-2, is expressed in multiple extrapulmonary tissues, direct viral tissue damage is a plausible mechanism of injury. In addition, endothelial damage and thromboinflammation, dysregulation of immune responses, and maladaptation of ACE2-related pathways might all contribute to these extrapulmonary manifestations of COVID-19. Here we review the extrapulmonary organ-specific pathophysiology, presentations and management considerations for patients with COVID-19 to aid clinicians and scientists in recognizing and monitoring the spectrum of manifestations, and in developing research priorities and therapeutic strategies for all organ systems involved.
Ageing hallmarks exhibit organ-specific temporal signatures.
Nature. 2020 Jul 15. doi: 10.1038/s41586-020-2499-y. Online ahead of print.
PMID: 32669715
Next-Generation Sequencing of T and B Cell Receptor
Repertoires from COVID-19 Patients Showed Signatures Associated with
Severity of Disease.
Immunity. 2020 Jun 30:S1074-7613(20)30279-X. doi: 10.1016/j.immuni.2020.06.024. Online ahead of print.
PMID: 32668194
Free PMC article.
N Engl J Med. 2020 Jul 16;383(3):207-217. doi: 10.1056/NEJMoa1916870.
PMID: 32668111