Synthetic nanobodies as tools to distinguish IgG Fc glycoforms.

Protein glycosylation is a crucial mediator of biological functions and is tightly regulated in health and disease. However, interrogating complex protein glycoforms is challenging, as current lectin tools are limited by cross-reactivity while mass spectrometry typically requires biochemical purification and isolation of the target protein. Here, we describe a method to identify and characterize a class of nanobodies that can distinguish glycoforms without reactivity to off-target glycoproteins or glycans. We apply this technology to immunoglobulin G (IgG) Fc glycoforms and define nanobodies that specifically recognize either IgG lacking its core-fucose or IgG bearing terminal sialic acid residues. By adapting these tools to standard biochemical methods, we can clinically stratify dengue virus and SARS-CoV-2 infected individuals based on their IgG glycan profile, selectively disrupt IgG-Fcγ receptor binding both in vitro and in vivo, and interrogate the B cell receptor (BCR) glycan structure on living cells. Ultimately, we provide a strategy for the development of reagents to identify and manipulate IgG Fc glycoforms.

LC-MS/MS-PRM Quantification of IgG Glycoforms Using Stable Isotope Labeled IgG1 Fc Glycopeptide Standard.

Targeted quantification of proteins is a standard methodology with broad utility, but targeted quantification of glycoproteins has not reached its full potential. The lack of optimized workflows and isotopically labeled standards limits the acceptance of glycoproteomics quantification. In this work, we introduce an efficient and streamlined chemoenzymatic synthesis of a library of isotopically labeled glycopeptides of IgG1 which we use for quantification in an energy optimized LC-MS/MS-PRM workflow. Incorporation of the stable isotope labeled N-acetylglucosamine enables an efficient monitoring of all major fragment ions of the glycopeptides generated under the soft higher-energy C-trap dissociation (HCD) conditions, which reduces the coefficients of variability (CVs) of the quantification to 0.7-2.8%. Our results document, for the first time, that the workflow using a combination of stable isotope labeled standards with intrascan normalization enables quantification of the glycopeptides by an electron transfer dissociation (ETD) workflow, as well as the HCD workflow, with the highest sensitivity compared to traditional workflows. This was exemplified by a rapid quantification (13 min) of IgG1 Fc glycoforms from COVID-19 patients.

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Coronavirus disease 2019 (COVID-19) has become a worldwide pandemic since the end of 2019. There is an increasing number of reports on nervous system symptoms, among which encephalitis is considered a serious neurological complication of COVID-19, but there are few reports of this complication in China. Acute encephalitis has severe symptoms. If it is not identified early and treated in time, the mortality is high and the prognosis is poor. During the current global epidemic, it is necessary to pay attention to the severe nervous system symptoms of COVID-19. Therefore, this article summarizes the clinical features of COVID-19 complicated by acute encephalitis through literature review and a detailed analysis of medical records, so as to provide a reference for clinicians to deal with the cases of COVID-19 complicated by acute encephalitis.

An intranasally administrated SARS-CoV-2 beta variant subunit booster vaccine prevents beta variant replication in rhesus macaques.

Emergence of SARS-CoV-2 variants and waning of vaccine/infection-induced immunity pose threats to curbing the COVID-19 pandemic. Effective, safe, and convenient booster vaccines are in need. We hypothesized that a variant-modified mucosal booster vaccine might induce local immunity to prevent SARS-CoV-2 infection at the port of entry. The beta-variant is one of the hardest to cross-neutralize. Herein, we assessed the protective efficacy of an intranasal booster composed of beta variant-spike protein S1 with IL-15 and TLR agonists in previously immunized macaques. The macaques were first vaccinated with Wuhan strain S1 with the same adjuvant. A total of 1 year later, negligibly detectable SARS-CoV-2-specific antibody remained. Nevertheless, the booster induced vigorous humoral immunity including serum- and bronchoalveolar lavage (BAL)-IgG, secretory nasal- and BAL-IgA, and neutralizing antibody against the original strain and/or beta variant. Beta-variant S1-specific CD4+ and CD8+ T cell responses were also elicited in PBMC and BAL. Following SARS-CoV-2 beta variant challenge, the vaccinated group demonstrated significant protection against viral replication in the upper and lower respiratory tracts, with almost full protection in the nasal cavity. The fact that one intranasal beta-variant booster administrated 1 year after the first vaccination provoked protective immunity against beta variant infections may inform future SARS-CoV-2 booster design and administration timing.

Guidelines for COVID-19 Laboratory Testing for Emergency Departments From the New Diagnostic Technology Team of the Taiwan Society of Emergency Medicine

COVID-19 tests have different turnaround times (TATs), accuracy levels, and limitations, which emergency physicians should be aware of. Nucleic acid amplification tests (NAATs) can be divided into standard high throughput tests and rapid molecular diagnostic tests at the point of care (POC). The standard NAAT has the advantages of high throughput and high accuracy with a TAT of 3–4 hours. The POC molecular test has the same advantages of high accuracy as standard high throughput PCR, but can be done in 13–45 minutes. Roche cobas Liat is the most commonly used machine in Taiwan, displaying 99%–100% sensitivity and 100% specificity, respectively. Abbott ID NOW is an isothermal PCR-based POC machine with a sensitivity of 79% and a specificity of 100%. A high rate of false positives and false negatives is associated with rapid antigen testing. Antibody testing is mostly used as part of public health surveys and for testing for immunity.

An interpretation on perinatal and neonatal management plan for prevention and control of SARS-CoV-2 infection (2nd Edition)

The epidemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection continues so far. The cases of SARS-CoV-2 infection have been reported in pregnant women and neonates as special groups. Perinatal and neonatal management plan for prevention and control of SARS-CoV-2 infection (2nd Edition) has been worked out by the Editorial Committee of Chinese Journal of Contemporary Pediatrics. This paper presents an interpretation on the 2nd Edition of the management plan, so as to facilitate readers to better understand it.

A facile chemoenzymatic synthesis of SARS-CoV-2 glycopeptides for probing glycosylation functions.

Glycosylation plays important roles in SARS-CoV-2 infection. We describe here a facile chemoenzymatic synthesis of core-fucosylated N-glycopeptides derived from the SARS-CoV-2 Spike protein and their binding with glycan-dependent neutralizing antibody S309 and human lectin CLEC4G. The synthetic glycopeptides provide tools for further functional characterization of viral glycosylation.

Protection against SARS-CoV-2 infection by a mucosal vaccine in rhesus macaques.

Effective SARS-CoV-2 vaccines are urgently needed. Although most vaccine strategies have focused on systemic immunization, here we compared the protective efficacy of 2 adjuvanted subunit vaccines with spike protein S1: an intramuscularly primed/boosted vaccine and an intramuscularly primed/intranasally boosted mucosal vaccine in rhesus macaques. The intramuscular-alum-only vaccine induced robust binding and neutralizing antibody and persistent cellular immunity systemically and mucosally, whereas intranasal boosting with nanoparticles, including IL-15 and TLR agonists, elicited weaker T cell and Ab responses but higher dimeric IgA and IFN-α. Nevertheless, following SARS-CoV-2 challenge, neither group showed detectable subgenomic RNA in upper or lower respiratory tracts versus naive controls, indicating full protection against viral replication. Although mucosal and systemic protective mechanisms may differ, results demonstrate both vaccines can protect against respiratory SARS-CoV-2 exposure. In summary, we have demonstrated that the mucosal vaccine was safe after multiple doses and cleared the input virus more efficiently in the nasal cavity and thus may act as a potent complementary reinforcing boost for conventional systemic vaccines to provide overall better protection.

Short-term developmental outcomes in neonates born to mothers with COVID-19 from Wuhan, China.

BACKGROUND: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an emerging disease. The consequences of SARS-CoV-2 exposure in infants remain unknown. Therefore, this study aims to investigate whether neonates born to mothers with COVID-19 have adverse brain development. METHODS: This multicenter observational study was conducted at two designated maternal and children's hospitals in Hubei Province, mainland China from February 1, 2020 to May 15, 2020. Neonates born to mothers with COVID-19 were enrolled. Brain magnetic resonance imaging (MRI) findings, and volumes of grey and white matters, and physical growth parameters were observed at 44 weeks corrected gestational age. RESULTS: Of 72 neonates born to mothers with COVID-19, 8 (11%) were diagnosed with COVID-19, 8 (11%) were critically ill, and no deaths were reported. Among the eight neonates that underwent brain MRI at corrected gestational age of 44 weeks, five neonates were diagnosed with COVID-19. Among these five neonates, three presented abnormal MRI findings including abnormal signal in white matter and delayed myelination in newborn 2, delayed myelination and brain dysplasia in newborn 3, and abnormal signal in the bilateral periventricular in newborn 5. The other three neonates without COVID-19 presented no significantly changes of brain MRI findings and the volumes of grey matter and white matter compared to those of healthy newborns at the equivalent age (P > 0.05). Physical growth parameters for weight, length, and head circumference at gestational age of 44 weeks were all above the 3rd percentile for all neonates. CONCLUSIONS: Some of the neonates born to mothers with COVID-19 had abnormal brain MRI findings but these neonates did not appear to have poor physical growth. These findings may provide the information on the follow-up schedule on the neonates exposed to SARS-CoV-2, but further study is required to evaluate the association between the abnormal MRI findings and the exposure to SARS-CoV-2.

An evidence mapping and analysis of registered COVID-19 clinical trials in China.

BACKGROUND: This article aims to summarize the key characteristics of registered trials of 2019 novel coronavirus (COVID-19), in terms of their spatial and temporal distributions, types of design and interventions, and patient characteristics among others. METHODS: A comprehensive search of the registered COVID-19 trials has been performed on platforms including ClinicalTrials.gov, WHO International Clinical Trials Registry Platform (WHO ICTRP), Chinese Clinical Trials Registry (CHiCTR), Australian Clinical Trials Registry, Britain's National Research Register (BNRR), Current Control Trials (CCT), and Glaxo Smith Kline Register. Trials registered at the first 8 weeks of the COVID-19 outbreak are included, without language restrictions. For each study, the registration information, study design, and administrator information are collected and summarized. RESULTS: A total of 220 registered trials were evaluated as of February 27, 2020. Hospital-initiated trials were the majority and account for 80% of the sample. Among the trials, pilot studies and phase 4 trials are more common and represent 35% and 19.1% of the sample, respectively. The median sample size of the registered trials is 100, with interquartile range 60-240. Further, 45.9% of the trials mentioned information on a data monitoring committee. 54.5% of the trials did not specify the disease severity among patients they intend to recruit. Four types of interventions are most common in the experimental groups across the registered studies: antiviral drugs, Traditional Chinese Medicine (TCM), biological agents, and hormone drugs. Among them, the TCM and biological agents are frequently used in pilot study and correspond to a variety of primary endpoints. In contrast, trials with antiviral drugs have more targeted primary outcomes such as "COVID-19 nucleic acid test" and "28-day mortality." CONCLUSIONS: We provide an evidence mapping and analysis of registered COVID-19 clinical trials in China. In particular, it is critical for ongoing and future studies to refine their research hypothesis and better identify their intervention therapies and the corresponding primary outcomes. It is also imperative for multiple public health divisions and research institutions to work together for integrative clinical data capture and sharing, with a common objective of improving future studies that evaluate COVID-19 interventions.