Conditional reprogrammed human limbal epithelial cell model for anti-SARS-CoV-2 drug screening.

To minimize the global pandemic COVID-19 spread, understanding the possible transmission routes of SARS-CoV-2 and discovery of novel antiviral drugs are necessary. We describe here that the virus can infect ocular surface limbal epithelial, but not other regions. Limbal supports wild type and mutant SARS-CoV-2 entry and replication depending on ACE2, TMPRSS2 and possibly other receptors, resulting in slight CPE and arising IL-6 secretion, which symbolizes conjunctivitis in clinical symptoms. With this limbal model, we have screened two natural product libraries and discovered several unreported drugs. Our data reveal important commonalities between COVID-19 and ocular infection with SARS-CoV-2, and establish an ideal cell model for drug screening and mechanism research.

Early Detection of the Emerging SARS-CoV-2 BA.2.86 Lineage Through Wastewater Surveillance Using a Mediator Probe PCR Assay - Shenzhen City, Guangdong Province, China, 2023.

Introduction: The emergence of the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineage, BA.2.86, has sparked global public health concerns for its potential heightened transmissibility and immune evasion. Utilizing data from Shenzhen's city-wide wastewater surveillance system, we highlight the presence of the BA.2.86 lineage in Shenzhen. Methods: A mediator probe polymerase chain reaction (PCR) assay was developed to detect the BA.2.86 lineage in wastewater by targeting a specific mutation (Spike: A264D). Between September 19 and December 10, 2023, 781 wastewater samples from 38 wastewater treatment plants (WWTPs) and 9 pump stations in ten districts of Shenzhen were examined. Through multiple short-amplicon sequencing, three positive samples were identified. Results: The BA.2.86 lineage was identified in the wastewater of Futian and Nanshan districts in Shenzhen on December 2, 2023. From December 2 to 10, a total of 21 BA.2.86-positive wastewater samples were found across 6 districts (Futian, Nanshan, Longhua, Baoan, Longgang, and Luohu) in Shenzhen. The weighted average viral load of the BA.2.86 lineage in Shenzhen's wastewater was 43.5 copies/L on December 2, increased to 219.8 copies/L on December 4, and then decreased to approximately 100 copies/L on December 6, 8, and 10. Conclusions: The mediator probe PCR assay, designed for swift detection of low viral concentrations of the BA.2.86 lineage in wastewater samples, shows promise for detecting different SARS-CoV-2 variants. Wastewater surveillance could serve as an early detection system for promptly identifying specific SARS-CoV-2 variants as they emerge.

Response of Human Retinal Microvascular Endothelial Cells to Influenza A (H1N1) Infection and the Underlying Molecular Mechanism.

Purpose: Whether H1N1 infection-associated ocular manifestations result from direct viral infections or systemic complications remains unclear. This study aimed to comprehensively elucidate the underlying causes and mechanism. Method: TCID50 assays was performed at 24, 48, and 72 hours to verify the infection of H1N1 in human retinal microvascular endothelial cells (HRMECs). The changes in gene expression profiles of HRMECs at 24, 48, and 72 hours were characterized using RNA sequencing technology. Differentially expressed genes (DEGs) were validated using real-time quantitative polymerase chain reaction and Western blotting. CCK-8 assay and scratch assay were performed to evaluate whether there was a potential improvement of proliferation and migration in H1N1-infected cells after oseltamivir intervention. Results: H1N1 can infect and replicate within HRMECs, leading to cell rounding and detachment. After H1N1 infection of HRMECs, 2562 DEGs were identified, including 1748 upregulated ones and 814 downregulated ones. These DEGs primarily involved in processes such as inflammation and immune response, cytokine-cytokine receptor interaction, signal transduction regulation, and cell adhesion. The elevated expression levels of CXCL10, CXCL11, CCL5, TLR3, C3, IFNB1, IFNG, STAT1, HLA, and TNFSF10 after H1N1 infection were reduced by oseltamivir intervention, reaching levels comparable to those in the uninfected group. The impaired cell proliferation and migration after H1N1 infection was improved by oseltamivir intervention. Conclusions: This study confirmed that H1N1 can infect HRMECs, leading to the upregulation of chemokines, which may cause inflammation and destruction of the blood-retina barrier. Moreover, early oseltamivir administration may reduce retinal inflammation and hemorrhage in patients infected with H1N1.

Influenza H7N9 virus disrupts the monolayer human brain microvascular endothelial cells barrier in vitro.

Influenza H7N9 virus causes human infections with about 40% case fatality rate. The severe cases usually present with pneumonia; however, some present with central nervous system complications. Pneumonia syndrome is attributed to the cytokine storm after infection with H7N9, but the pathogenic mechanism of central nervous system complications has not been clarified. This study used immortalized human brain microvascular endothelial cells hCMEC/D3 to simulate the blood-brain barrier. It demonstrated that H7N9 virus could infect brain microvascular endothelial cells and compromise the blood-brain barrier integrity and permeability by down-regulating the expression of cell junction-related proteins, including claudin-5, occludin, and vascular endothelial (VE)-cadherin. These results suggested that H7N9 could infect the blood-brain barrier in vitro and affect its functions, which could be a potential mechanism for the pathogenesis of H7N9 viral encephalopathy.

Direct blue 53, a biological dye, inhibits SARS-CoV-2 infection by blocking ACE2 and spike interaction in vitro and in vivo.

COVID-19 is a global health problem caused by SARS-CoV-2, which has led to over 600 million infections and 6 million deaths. Developing novel antiviral drugs is of pivotal importance to slow down the epidemic swiftly. In this study, we identified five azo compounds as effective antiviral drugs to SARS-CoV-2, and mechanism study revealed their targets for impeding viral particles' ability to bind to host receptors. Direct Blue 53, which displayed the strongest inhibitory impact, inhibited five mutant strains at micromole. In vitro, mechanism study demonstrated Direct Blue 53 inhibited viral infection through interaction with the spike of SARS-CoV-2. And 25 mg/kg/d compound treatment showed 50% or 60% survival protection against lethal Delta or Omicron BA.2 infection in vivo. Taken together, our results demonstrate that azo compounds with dimethyl-biphenyl-diyl-bis(azo)bis structure may be promising anti-SARS-CoV-2 drug candidates, which provide practicable therapies with the aid of structural optimizations and further research.

The truncated IFITM3 facilitates the humoral immune response in inactivated influenza vaccine-vaccinated mice via interaction with CD81.

A single-nucleotide polymorphism (SNP) rs12252-C of interferon-induced transmembrane protein 3 (IFITM3), resulting in a truncated IFITM3 protein lacking 21 N-terminus amino acids, is associated with severe influenza infection in the Chinese population. However, the effect of IFITM3 rs12252-C on influenza vaccination and the underlying mechanism is poorly understood. Here, we constructed a mouse model with a deletion of 21 amino acids at the N-terminus (NΔ21) of IFITM3 and then compared the antibody response between Quadrivalent influenza vaccine (QIV) immunized wild-type (WT) mice and NΔ21 mice. Significantly higher levels of haemagglutination inhibition (HI) titre, neutralizing antibodies (NAb), and immunoglobulin G (IgG) to H1N1, H3N2, B/Victory, and B/Yamagata viruses were observed in NΔ21 mice compared to WT mice. Correspondingly, the numbers of splenic germinal centre (GC) B cells, plasma cells, memory B cells, QIV-specific IgG+ antibody-secreting cells (ASC), and T follicular helper cells (TFH) in NΔ21 mice were higher compared with WT mice. Moreover, the 21-amino-acid deletion caused IFITM3 translocation from the endocytosis compartment to the periphery of cells, which also prevented the degradation of a co-stimulatory molecule of B cell receptor (BCR) CD81 on the cell surface. More importantly, a more interaction was observed between NΔ21 protein and CD81 compared to the interaction between IFITM3 and CD81. Overall, our study revealed a potential mechanism of NΔ21 protein enhancing humoral immune response by relocation to prevent the degradation of CD81, providing insight into SNP affecting influenza vaccination.

Screening and identification of specific cluster miRNAs in N2a cells infected by H7N9 virus.

This study aims to screen and identify specific cluster miRNAs of H7N9 virus-infected N2a cells and explore the possible pathogenesis of these miRNAs. The N2a cells are infected with H7N9 and H1N1 influenza viruses, and the cells are collected at 12, 24 and 48 h to extract total RNA. To sequence miRNAs and identify different virus-specific miRNAs, high-throughput sequencing technology is used. Fifteen H7N9 virus-specific cluster miRNAs are screened, and eight of them are included in the miRBase database. These cluster-specific miRNAs regulate many signaling pathways, such as the PI3K-Akt signaling pathway, the RAS signaling pathway, the cAMP signaling pathway, actin cytoskeleton regulation and cancer-related genes. The study provides a scientific basis for the pathogenesis of H7N9 avian influenza, which is regulated by miRNAs.

ZIKV infection differentially affects the transcriptional profiles in HTR8 and U251 cells.

The mechanism by which Zika virus (ZIKV) causes severe birth defects in pregnant women remains unclear. Cell tropisms in placenta and brain play a crucial role in ZIKV pathogenesis, leading to congenital Zika syndrome (CZS). To identify the host factors involved in ZIKV infection, we compared the transcriptional profiles of ZIKV-infected human first-trimester placental trophoblast cells HTR8/SVneo and a human glioblastoma astrocytoma cell line U251. Our results demonstrated that ZIKV exhibited lower rates of mRNA replication and protein expression in HTR8 than in U251 cells, while showing a higher release of infectious viral particles. However, a greater number of differentially expressed genes (DEGs) were found in ZIKV-infected U251 cells than in ZIKV-infected HTR8 cells. Several of these DEGs were enriched in distinct biological processes related to the characteristics of each cell type that may contribute to foetal damage. Both cell types exhibited activation of common interferons, inflammatory cytokines, and chemokine production upon ZIKV infection. Moreover, the neutralization of tumour necrosis factor-alpha (TNF-α) promoted ZIKV infection in both trophoblasts and glioblastoma astrocytoma cells. Overall, we identified multiple DEGs associated with ZIKV pathogenesis.

A glucose-like metabolite deficient in diabetes inhibits cellular entry of SARS-CoV-2.

The severity and mortality of COVID-19 are associated with pre-existing medical comorbidities such as diabetes mellitus. However, the underlying causes for increased susceptibility to viral infection in patients with diabetes is not fully understood. Here we identify several small-molecule metabolites from human blood with effective antiviral activity against SARS-CoV-2, one of which, 1,5-anhydro-D-glucitol (1,5-AG), is associated with diabetes mellitus. The serum 1,5-AG level is significantly lower in patients with diabetes. In vitro, the level of SARS-CoV-2 replication is higher in the presence of serum from patients with diabetes than from healthy individuals and this is counteracted by supplementation of 1,5-AG to the serum from patients. Diabetic (db/db) mice undergo SARS-CoV-2 infection accompanied by much higher viral loads and more severe respiratory tissue damage when compared to wild-type mice. Sustained supplementation of 1,5-AG in diabetic mice reduces SARS-CoV-2 loads and disease severity to similar levels in nondiabetic mice. Mechanistically, 1,5-AG directly binds the S2 subunit of the SARS-CoV-2 spike protein, thereby interrupting spike-mediated virus-host membrane fusion. Our results reveal a mechanism that contributes to COVID-19 pathogenesis in the diabetic population and suggest that 1,5-AG supplementation may be beneficial to diabetic patients against severe COVID-19.

The effect of influenza A (H1N1) pdm09 virus infection on cytokine production and gene expression in BV2 microglial cells.

Acute influenza infection has been reported to be associated with neurological symptoms such as influenza-associated encephalopathy (IAE). Although the pathophysiology of this condition remain unclear, neuroinflammation and associated alterations in the central nervous system (CNS) are usually induced. Microglia (MGs), CNS-resident macrophages, are generally the first cells to be activated in response to brain infection or damage. We performed reverse transcriptase droplet digital PCR (RT-ddPCR) and luminex assays to investigate virus proliferation and immune reactions in BV2 MGs infected with influenza A(H1N1)pdm09 virus. Furthermore, isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics methods were used to investigate the dynamic change in the protein expression profile in BV2 MGs to gain insight into the CNS response to influenza A (H1N1) pdm09 infection. Our results showed that the influenza A(H1N1)pdm09 virus was replicative and productive in BV2 MG cells, which produced cytokines such as interleukin (IL)-1ß, IL-6, tumour necrosis factor (TNF)-α and monocyte chemoattractant protein (MCP)-1. The expression of osteopontin (OPN) in the influenza A (H1N1) pdm09-infected BV2 MGs was upregulated at 16 and 32 h post-infection (hpi) compared to that in the control group, resulting in aggravated brain damage and inflammation. Our study indicates that OPN signalling might provide new insights into the treatment of CNS injury and neurodegenerative diseases in IAE.

Simultaneous detection of Zika, chikungunya, dengue, yellow fever, West Nile, and Japanese encephalitis viruses by a two-tube multiplex real-time RT-PCR assay.

Due to the concurrent prevalence and increasing risk of coinfection of the clinically important Arboviruses, timely and accurate differential diagnosis is important for clinical management and the epidemiological investigation. A two-tube multiplex real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for the simultaneous detection of Zika virus (ZIKV), chikungunya virus (CHIKV), dengue virus (DENV), yellow fever virus (YFV), West Nile virus (WNV), and Japanese encephalitis virus (JEV) was developed and optimized with high specificity and sensitivity. The detection limit for all the six viruses could reach as low as five genome equivalent copies and 2.8 × 10-3 tissue culture infectious doses (TCID50 ) for ZIKV, YFV, CHIKV and 2.8 × 10-2 TCID50  for JEV per reaction, with high accuracy and precision (R2 > 0.99). The coefficient of variation of intra-assay and inter-assay for our quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay was low, and the obtained positive rates ad Ct values of this assay were comparable with singleplex commercial kits. Moreover, the multiplex qRT-PCR assay was able to detect possible co-infections without competitive inhibition of target viral genomes. In conclusion, our rapid, sensitive, cost-effective multiplex qRT-PCR will be of great use for differential diagnosis in a clinical setting and epidemiological investigation during surveillance.

SARS-CoV-2 non-structural protein 6 triggers NLRP3-dependent pyroptosis by targeting ATP6AP1.

A recent mutation analysis suggested that Non-Structural Protein 6 (NSP6) of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a key determinant of the viral pathogenicity. Here, by transcriptome analysis, we demonstrated that the inflammasome-related NOD-like receptor signaling was activated in SARS-CoV-2-infected lung epithelial cells and Coronavirus Disease 2019 (COVID-19) patients' lung tissues. The induction of inflammasomes/pyroptosis in patients with severe COVID-19 was confirmed by serological markers. Overexpression of NSP6 triggered NLRP3/ASC-dependent caspase-1 activation, interleukin-1ß/18 maturation, and pyroptosis of lung epithelial cells. Upstream, NSP6 impaired lysosome acidification to inhibit autophagic flux, whose restoration by 1α,25-dihydroxyvitamin D3, metformin or polydatin abrogated NSP6-induced pyroptosis. NSP6 directly interacted with ATP6AP1, a vacuolar ATPase proton pump component, and inhibited its cleavage-mediated activation. L37F NSP6 variant, which was associated with asymptomatic COVID-19, exhibited reduced binding to ATP6AP1 and weakened ability to impair lysosome acidification to induce pyroptosis. Consistently, infection of cultured lung epithelial cells with live SARS-CoV-2 resulted in autophagic flux stagnation, inflammasome activation, and pyroptosis. Overall, this work supports that NSP6 of SARS-CoV-2 could induce inflammatory cell death in lung epithelial cells, through which pharmacological rectification of autophagic flux might be therapeutically exploited.

Generation and Effect Testing of a SARS-CoV-2 RBD-Targeted Polyclonal Therapeutic Antibody Based on a 2-D Airway Organoid Screening System.

Coronavirus disease 2019 (COVID-19) is an acute respiratory infectious disease caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The US FDA has approved several therapeutics and vaccines worldwide through the emergency use authorization in response to the rapid spread of COVID-19. Nevertheless, the efficacies of these treatments are being challenged by viral escape mutations. There is an urgent need to develop effective treatments protecting against SARS-CoV-2 infection and to establish a stable effect-screening model to test potential drugs. Polyclonal antibodies (pAbs) have an intrinsic advantage in such developments because they can target rapidly mutating viral strains as a result of the complexity of their binding epitopes. In this study, we generated anti-receptor-binding domain (anti-RBD) pAbs from rabbit serum and tested their safety and efficacy in response to SARS-CoV-2 infection both in vivo and ex vivo. Primary human bronchial epithelial two-dimensional (2-D) organoids were cultured and differentiated to a mature morphology and subsequently employed for SARS-CoV-2 infection and drug screening. The pAbs protected the airway organoids from viral infection and tissue damage. Potential side effects were tested in mouse models for both inhalation and vein injection. The pAbs displayed effective viral neutralization effects without significant side effects. Thus, the use of animal immune serum-derived pAbs might be a potential therapy for protection against SARS-CoV-2 infection, with the strategy developed to produce these pAbs providing new insight into the treatment of respiratory tract infections, especially for infections with viruses undergoing rapid mutation.

Outcomes of respiratory viral-bacterial co-infection in adult hospitalized patients.

BACKGROUND: Viral infections of the respiratory tract represent a major global health concern. Co-infection with bacteria may contribute to severe disease and increased mortality in patients. Nevertheless, viral-bacterial co-infection patterns and their clinical outcomes have not been well characterized to date. This study aimed to evaluate the clinical features and outcomes of patients with viral-bacterial respiratory tract co-infections. METHODS: We included 19,361 patients with respiratory infection due to respiratory viruses [influenza A and B, respiratory syncytial virus (RSV), parainfluenza] and/or bacteria in four tertiary hospitals in Hong Kong from 2013 to 2017 using a large territory-wide healthcare database. All microbiological tests were conducted within 48 h of hospital admission. Four etiological groups were included: (1) viral infection alone; (2) bacterial infection alone; (3) laboratory-confirmed viral-bacterial co-infection and (4) clinically suspected viral-bacterial co-infection who were tested positive for respiratory virus and negative for bacteria but had received at least four days of antibiotics. Clinical features and outcomes were recorded for laboratory-confirmed viral-bacterial co-infection patients compared to other three groups as control. The primary outcome was 30-day mortality. Secondary outcomes were intensive care unit (ICU) admission and length of hospital stay. Propensity score matching estimated by binary logistic regression was used to adjust for the potential bias that may affect the association between outcomes and covariates. FINDINGS: Among 15,906 patients with respiratory viral infection, there were 8451 (53.1%) clinically suspected and 1,087 (6.8%) laboratory-confirmed viral-bacterial co-infection. Among all the bacterial species, Haemophilus influenzae (226/1,087, 20.8%), Pseudomonas aeruginosa (180/1087, 16.6%) and Streptococcus pneumoniae (123/1087, 11.3%) were the three most common bacterial pathogens in the laboratory-confirmed co-infection group. Respiratory viruses co-infected with non-pneumococcal streptococci or methicillin-resistant Staphylococcus aureus was associated with the highest death rate [9/30 (30%) and 13/48 (27.1%), respectively] in this cohort. Compared with other infection groups, patients with laboratory-confirmed co-infection had higher ICU admission rate (p < 0.001) and mortality rate at 30 days (p = 0.028), and these results persisted after adjustment for potential confounders using propensity score matching. Furthermore, patients with laboratory-confirmed co-infection had significantly higher mortality compared to patients with bacterial infection alone. INTERPRETATION: In our cohort, bacterial co-infection is common in hospitalized patients with viral respiratory tract infection and is associated with higher ICU admission rate and mortality. Therefore, active surveillance for bacterial co-infection and early antibiotic treatment may be required to improve outcomes in patients with respiratory viral infection.

SOD1 is a Possible Predictor of COVID-19 Progression as Revealed by Plasma Proteomics.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a worldwide health emergency. Patients infected with SARS-CoV-2 present with diverse symptoms related to the severity of the disease. Determining the proteomic changes associated with these diverse symptoms and in different stages of infection is beneficial for clinical diagnosis and management. Here, we performed a tandem mass tag-labeling proteomic study on the plasma of healthy controls and COVID-19 patients, including those with asymptomatic infection (NS), mild syndrome, and severe syndrome in the early phase and the later phase. Although the number of patients included in each group is low, our comparative proteomic analysis revealed that complement and coagulation cascades, cholesterol metabolism, and glycolysis-related proteins were affected after infection with SARS-CoV-2. Compared to healthy controls, ELISA analysis confirmed that SOD1, PRDX2, and LDHA levels were increased in the patients with severe symptoms. Both gene set enrichment analysis and receiver operator characteristic analysis indicated that SOD1 could be a pivotal indicator for the severity of COVID-19. Our results indicated that plasma proteome changes differed based on the symptoms and disease stages and SOD1 could be a predictor protein for indicating COVID-19 progression. These results may also provide a new understanding for COVID-19 diagnosis and treatment.

Comparative evaluation of six nucleic acid amplification kits for SARS-CoV-2 RNA detection.

BACKGROUND: SARS-CoV-2 is a newly emerged coronavirus, causing the coronavirus disease 2019 (COVID-19) outbreak in December, 2019. As drugs and vaccines of COVID-19 remain in development, accurate virus detection plays a crucial role in the current public health crisis. Quantitative real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) kits have been reliably used for detection of SARS-CoV-2 RNA since the beginning of the COVID-19 outbreak, whereas isothermal nucleic acid amplification-based point-of-care automated kits have also been considered as a simpler and rapid alternative. However, as these kits have only been developed and applied clinically within a short timeframe, their clinical performance has not been adequately evaluated to date. We describe a comparative study between a newly developed cross-priming isothermal amplification (CPA) kit (Kit A) and five RT-qPCR kits (Kits B-F) to evaluate their sensitivity, specificity, predictive values and accuracy. METHODS: Fifty-two clinical samples were used including throat swabs (n = 30), nasal swabs (n = 7), nasopharyngeal swabs (n = 7) and sputum specimens (n = 8), comprising confirmed (n = 26) and negative cases (n = 26). SARS-CoV-2 detection was simultaneously performed on each sample using six nucleic acid amplification kits. The sensitivity, specificity, positive/negative predictive values (PPV/NPV) and the accuracy for each kit were assessed using clinical manifestation and molecular diagnoses as the reference standard. Reproducibility for RT-qPCR kits was evaluated in triplicate by three different operators using a SARS-CoV-2 RNA-positive sample. On the basis of the six kits' evaluation results, CPA kit (Kit A) and two RT-qPCR Kits (Kit B and F) were applied to the SARS-CoV-2 detection in close-contacts of COVID-19 patients. RESULTS: For Kit A, the sensitivity, specificity, PPV/NPV and accuracy were 100%. Among the five RT-qPCR kits, Kits B, C and F had good agreement with the clinical diagnostic reports (Kappa ≥ 0.75); Kits D and E were less congruent (0.4 ≤ Kappa < 0.75). Differences between all kits were statistically significant (P < 0.001). The reproducibility of RT-qPCR kits was determined using a coefficients of variation (CV) between 0.95% and 2.57%, indicating good reproducibility. CONCLUSIONS: This is the first comparative study to evaluate CPA and RT-qPCR kits' specificity and sensitivity for SARS-CoV-2 detection, and could serve as a reference for clinical laboratories, thus informing testing protocols amid the rapidly progressing COVID-19 pandemic.

The Characterization of Disease Severity Associated IgG Subclasses Response in COVID-19 Patients.

Increasing evidence suggests that dysregulated immune responses are associated with the clinical outcome of coronavirus disease 2019 (COVID-19). Nucleocapsid protein (NP)-, spike (S)-, receptor binding domain (RBD)- specific immunoglobulin (Ig) isotypes, IgG subclasses and neutralizing antibody (NAb) were analyzed in 123 serum from 63 hospitalized patients with severe, moderate, mild or asymptomatic COVID-19. Mild to modest correlations were found between disease severity and antigen specific IgG subclasses in serum, of which IgG1 and IgG3 were negatively associated with viral load in nasopharyngeal swab. Multiple cytokines were significantly related with antigen-specific Ig isotypes and IgG subclasses, and IL-1ß was positively correlated with most antibodies. Furthermore, the old patients (≥ 60 years old) had higher levels of chemokines, increased NAb activities and SARS-CoV-2 specific IgG1, and IgG3 responses and compromised T cell responses compared to the young patients (≤ 18 years old), which are related with more severe cases. Higher IgG1 and IgG3 were found in COVID-19 patients with comorbidities while biological sex had no effect on IgG subclasses. Overall, we have identified diseases severity was related to higher antibodies, of which IgG subclasses had weakly negative correlation with viral load, and cytokines were significantly associated with antibody response. Further, advancing age and comorbidities had obvious effect on IgG1 and IgG3.

Peroxide- and transition metal-free electrochemical synthesis of α,ß-epoxy ketones.

A novel electrochemical method for the synthesis of α,ß-epoxy ketones is reported. With KI as the redox mediator, methyl ketones reacted with aldehydes under peroxide- and transition metal-free electrolytic conditions and afforded α,ß-epoxy ketones in one pot (36 examples, 52-90% yield). This safe and environmental-friendly method has a broad substrate scope and can readily provide a variety of α,ß-epoxy ketones in gram-scales for evaluation of their anti-cancer activities.