A rapid and highly sensitive multiple detection of human adenovirus type 3, type 7 and respiratory syncytial virus by recombinase-aided reverse transcription PCR.

BACKGROUND: Polymerase chain reaction (PCR) has been widely used for many pathogen detection. However, PCR technology still suffers from long detection time and insufficient sensitivity. Recombinase-aided amplification (RAA) is a powerful nucleic acid detection tool with high sensitivity and amplification efficiency, but its complex probes and inability of multiplex detection hinder the further application of this technology. METHODS: In this study, we developed and validated the multiplex reverse transcription recombinase-aided PCR (multiplex RT-RAP) assay for human adenovirus 3 (HADV3), human adenovirus 7 (HADV7), and human respiratory syncytial virus (HRSV) within 1 h with Human RNaseP protein as a reference gene to monitor the whole process. RESULTS: Using recombinant plasmids, the sensitivity of multiplex RT-RAP for the detection of HADV3, HADV7, and HRSV was 18, 3, and 18 copies per reaction, respectively. The multiplex RT-RAP showed no cross-reactivity with other respiratory viruses, demonstrating its good specificity. A total of 252 clinical specimens were tested by multiplex RT-RAP and the results were found to be consistent with those of corresponding RT-qPCR assays. After testing serial dilutions of selected positive specimens, the detection sensitivity of multiplex RT-RAP was two to eightfold higher than that of corresponding RT-qPCR. CONCLUSION: We conclude the multiplex RT-RAP is a robust, rapid, highly sensitive, and specific assay with the potential to be used in the screening of clinical samples with low viral load.

COVID-19 and employee job performance trajectories: The moderating effect of different sources of status

This study investigates the impact of the COVID-19 pandemic on employee job performance trajectories, and further examines the moderating effects of different sources of status. Drawing from event system theory (EST), we propose that employee job performance decreases upon COVID-19 onset, but gradually increases during the postonset period. Furthermore, we argue that status from society, occupation, and workplace functions to moderate such performance trajectories. We test our hypotheses with a unique dataset of 708 employees that combines survey responses and job performance archival data over 21 consecutive months (10,808 observations) spanning the preonset, onset, and postonset periods of the initial encounter with COVID-19 in China. Utilizing discontinuous growth modeling (DGM), our findings indicate that the onset of COVID-19 created an immediate decrease in job performance, but such decrease was weakened by higher occupation and/or workplace status. However, the postonset period resulted in a positive employee job performance trajectory, which was strengthened for employees with lower occupational status. These findings enrich our understanding of COVID-19's impact on employee job performance trajectories, highlight the role of status in moderating such changes over time, and also provide practical implications to understand employee performance when facing such a crisis.

COVID-19 and employee job performance trajectories: The moderating effect of different sources of status.

This study investigates the impact of the COVID-19 pandemic on employee job performance trajectories, and further examines the moderating effects of different sources of status. Drawing from event system theory (EST), we propose that employee job performance decreases upon COVID-19 onset, but gradually increases during the postonset period. Furthermore, we argue that status from society, occupation, and workplace functions to moderate such performance trajectories. We test our hypotheses with a unique dataset of 708 employees that combines survey responses and job performance archival data over 21 consecutive months (10,808 observations) spanning the preonset, onset, and postonset periods of the initial encounter with COVID-19 in China. Utilizing discontinuous growth modeling (DGM), our findings indicate that the onset of COVID-19 created an immediate decrease in job performance, but such decrease was weakened by higher occupation and/or workplace status. However, the postonset period resulted in a positive employee job performance trajectory, which was strengthened for employees with lower occupational status. These findings enrich our understanding of COVID-19's impact on employee job performance trajectories, highlight the role of status in moderating such changes over time, and also provide practical implications to understand employee performance when facing such a crisis.

Extending a helping hand: How receiving gratitude makes a difference in employee performance during a crisis

Although organizational crises, particularly the COVID-19 pandemic, are shocks for employees, their expression of gratitude can be viewed as a silver lining. Drawing on social exchange theory and the social functions of emotion perspective, we develop a model that elucidates why and when benefactors who receive gratitude expression can perform better in the COVID-19 crisis. We propose that receiving gratitude expression as a potential consequence of providing crisis-related help to coworkers enhances one’s crisis self-efficacy and perceived social impact, which, in turn, positively relates to adaptation to a crisis, task performance, and helping behaviors toward leaders. The perceived novelty of the COVID-19 crisis strengthens the positive effect of receiving gratitude expression on crisis self-efficacy, and the perceived criticality of the crisis strengthens the positive effect of receiving gratitude expression on perceived social impact. A scenario-based experiment and five-wave field survey with Eastern and Western employees generally support our hypotheses.

Antigenicity comparison of SARS-CoV-2 Omicron sublineages with other variants contained multiple mutations in RBD.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, particularly those with multiple mutations in receptor-binding domain (RBD), pose a critical challenge to the efficacy of coronavirus disease 2019 (COVID-19) vaccines and therapeutic neutralizing monoclonal antibodies (mAbs). Omicron sublineages BA.1, BA.2, BA.3, as well as the recent emergence of C.1.2, B.1.630, B.1.640.1, and B.1.640.2, have multiple mutations in RBD and may lead to severe neutralizing antibody evasion. It is urgent to evaluate the antigenic change of the above seven variants against mAbs and sera from guinea pigs immunized with variants of concern (VOCs) (Alpha, Beta, Gamma, Delta, Omicron) and variants of interest (VOIs) (Lambda, Mu) immunogens. Only seven out of the 24 mAbs showed no reduction in neutralizing activity against BA.1, BA.2, and BA.3. However, among these seven mAbs, the neutralization activity of XGv337 and XGv338 against C.1.2, B.1.630, B.1.640.1, and B.1.640.2 were decreased. Therefore, only five neutralizing mAbs showed no significant change against these seven variants. Using VOCs and VOIs as immunogens, we found that the antigenicity of variants could be divided into three clusters, and each cluster showed similar antigenicity to different immunogens. Among them, D614G, B.1.640.1, and B.1.630 formed a cluster, C.1.2 and B.1.640.2 formed a cluster, and BA.1, BA.2, and BA.3 formed a cluster.

Cover Image, Volume 94, Number 5, May 2022

Front Cover Caption: The cover image is based on the Research Article Aggregation of high-frequency RBD mutations of SARS-CoV-2 with three VOCs did not cause significant antigenic drift by Tao Li et al., https://doi.org/10.1002/jmv.27596.

The antigenicity of SARS-CoV-2 Delta variants aggregated 10 high-frequency mutations in RBD has not changed sufficiently to replace the current vaccine strain.

Emerging SARS-CoV-2 variants are the most serious problem for COVID-19 prophylaxis and treatment. To determine whether the SARS-CoV-2 vaccine strain should be updated following variant emergence like seasonal flu vaccine, the changed degree on antigenicity of SARS-CoV-2 variants and H3N2 flu vaccine strains was compared. The neutralization activities of Alpha, Beta and Gamma variants' spike protein-immunized sera were analysed against the eight current epidemic variants and 20 possible variants combining the top 10 prevalent RBD mutations based on the Delta variant, which were constructed using pseudotyped viruses. Meanwhile, the neutralization activities of convalescent sera and current inactivated and recombinant protein vaccine-elicited sera were also examined against all possible Delta variants. Eight HA protein-expressing DNAs elicited-animal sera were also tested against eight pseudotyped viruses of H3N2 flu vaccine strains from 2011-2019. Our results indicate that the antigenicity changes of possible Delta variants were mostly within four folds, whereas the antigenicity changes among different H3N2 vaccine strains were approximately 10-100-fold. Structural analysis of the antigenic characterization of the SARS-CoV-2 and H3N2 mutations supports the neutralization results. This study indicates that the antigenicity changes of the current SARS-CoV-2 may not be sufficient to require replacement of the current vaccine strain.

Aggregation of high-frequency RBD mutations of SARS-CoV-2 with three VOCs did not cause significant antigenic drift.

Variants of SARS-CoV-2 continue to emerge, posing great challenges in outbreak prevention and control. It is important to understand in advance the impact of possible variants of concern (VOCs) on infectivity and antigenicity. Here, we constructed one or more of the 15 high-frequency naturally occurring amino acid changes in the receptor-binding domain (RBD) of Alpha, Beta, and Gamma variants. A single mutant of A520S, V367F, and S494P in the above three VOCs enhanced infectivity in ACE2-overexpressing 293T cells of different species, LLC-MK2 and Vero cells. Aggregation of multiple RBD mutations significantly reduces the infectivity of the possible three VOCs. Regarding neutralization, it is noteworthy that E484K, N501Y, K417N, and N439K predispose to monoclonal antibodies (mAbs) protection failure in the 15 high-frequency mutations. Most importantly, almost all possible VOCs (single RBD mutation or aggregation of multiple mutations) showed no more than a fourfold decrease in neutralizing activity with convalescent sera, vaccine sera, and immune sera of guinea pigs with different immunogens, and no significant antigenic drift was formed. In conclusion, our pseudovirus results could reduce the concern that the aggregation of multiple high-frequency mutations in the RBD of the spike protein of the three VOCs would lead to severe antigenic drift, and this would provide value for vaccine development strategies.

Elastase Inhibitor Cyclotheonellazole A: Total Synthesis and In Vivo Biological Evaluation for Acute Lung Injury.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is one of the most common complications in COVID-19. Elastase has been recognized as an important target to prevent ALI/ARDS in the patient of COVID-19. Cyclotheonellazole A (CTL-A) is a natural macrocyclic peptide reported to be a potent elastase inhibitor. Herein, we completed the first total synthesis of CTL-A in 24 linear steps. The key reactions include three-component MAC reactions and two late-stage oxidations. We also provided seven CTL-A analogues and elucidated preliminary structure-activity relationships. The in vivo ALI mouse model further suggested that CTL-A alleviated acute lung injury with reductions in lung edema and pathological deterioration, which is better than sivelestat, one approved elastase inhibitor. The activity of CTL-A against elastase, along with its cellular safety and well-established synthetic route, warrants further investigation of CTL-A as a candidate against COVID-19 pathogeneses.

Antibody-dependent cellular cytotoxicity response to SARS-CoV-2 in COVID-19 patients.

Antibody-dependent cellular cytotoxicity (ADCC) responses to viral infection are a form of antibody regulated immune responses mediated through the Fc fragment. Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggered ADCC responses contributes to COVID-19 disease development is currently not well understood. To understand the potential correlation between ADCC responses and COVID-19 disease development, we analyzed the ADCC activity and neutralizing antibody response in 255 individuals ranging from asymptomatic to fatal infections over 1 year post disease. ADCC was elicited by 10 days post-infection, peaked by 11-20 days, and remained detectable until 400 days post-infection. In general, patients with severe disease had higher ADCC activities. Notably, patients who had severe disease and recovered had higher ADCC activities than patients who had severe disease and deceased. Importantly, ADCC activities were mediated by a diversity of epitopes in SARS-COV-2-infected mice and induced to comparable levels against SARS-CoV-2 variants of concern (VOCs) (B.1.1.7, B.1.351, and P.1) as that against the D614G mutant in human patients and vaccinated mice. Our study indicates anti-SARS-CoV-2 ADCC as a major trait of COVID-19 patients with various conditions, which can be applied to estimate the extra-neutralization level against COVID-19, especially lethal COVID-19.

Functional comparison of SARS-CoV-2 with closely related pangolin and bat coronaviruses.

The origin and intermediate host for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is yet to be determined. Coronaviruses found to be closely related to SARS-CoV-2 include RaTG13 derived from bat and two clusters (PCoV-GD and PCoV-GX) of coronaviruses identified in pangolin. Here, we studied the infectivity and antigenicity patterns of SARS-CoV-2 and the three related coronaviruses. Compared with the other three viruses, RaTG13 showed almost no infectivity to a variety of cell lines. The two pangolin coronaviruses and SARS-CoV-2 showed similar infectious activity. However, in SARS-CoV-2-susceptible cell lines, the pangolin coronaviruses presented even higher infectivity. The striking difference between the SARS-CoV-2 and pangolin coronaviruses is that the latter can infect porcine cells, which could be partially attributed to an amino acid difference at the position of 498 of the spike protein. The infection by SARS-CoV-2 was mainly mediated by Furin and TMPRSS2, while PCoV-GD and PCoV-GX mainly depend on Cathepsin L. Extensive cross-neutralization was found between SARS-CoV-2 and PCoV-GD. However, almost no cross-neutralization was observed between PCoV-GX and SARS-CoV-2 or PCoV-GD. More attention should be paid to pangolin coronaviruses and to investigate the possibility of these coronaviruses spreading across species to become zoonoses among pigs or humans.

SARS-CoV-2 501Y.V2 variants lack higher infectivity but do have immune escape.

The 501Y.V2 variants of SARS-CoV-2 containing multiple mutations in spike are now dominant in South Africa and are rapidly spreading to other countries. Here, experiments with 18 pseudotyped viruses showed that the 501Y.V2 variants do not confer increased infectivity in multiple cell types except for murine ACE2-overexpressing cells, where a substantial increase in infectivity was observed. Notably, the susceptibility of the 501Y.V2 variants to 12 of 17 neutralizing monoclonal antibodies was substantially diminished, and the neutralization ability of the sera from convalescent patients and immunized mice was also reduced for these variants. The neutralization resistance was mainly caused by E484K and N501Y mutations in the receptor-binding domain of spike. The enhanced infectivity in murine ACE2-overexpressing cells suggests the possibility of spillover of the 501Y.V2 variants to mice. Moreover, the neutralization resistance we detected for the 501Y.V2 variants suggests the potential for compromised efficacy of monoclonal antibodies and vaccines.