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Background The COVID-19 pandemic highlighted the need for evidence-based approaches to decontamination and reuse of N95 filtering facepiece respirators (FFRs). We sought to determine whether vapourized hydrogen peroxide (VHP) reduced SARS-CoV-2 bioburden on FFRs without compromising filtration efficiency. We also investigated coronavirus HCoV-229E as a surrogate for decontamination validation testing. Methods N95 FFRs were laced with SARS-CoV-2 or HCoV-229E and treated with VHP in a hospital reprocessing facility. After sterilization, viral burden was determined using viral outgrowth in a titration assay, and filtration efficiency of FFRs was tested against ATSM F2299 and NIOSH TEB-STP-APR-0059. Results Viable SARS-CoV-2 virus was not detected after VHP treatment. One replicate of the HCoV-229E laced FFRs yielded virus after processing. Unexpired N95 FFRs retained full filtration efficiency after VHP processing. Expired FFRs failed to meet design-specified filtration efficiency and therefore are unsuitable for reprocessing. Discussion In-hospital VHP is an effective decontaminant for SARS-CoV-2 on FFRs. Further, filtration efficiency of unexpired respirators is not affected by this decontamination process. Conclusions VHP is effective in inactivating SARS-CoV-2 on FFRs without compromising filtration efficiency. HCoV-229E is a suitable surrogate for SARS-CoV-2 for disinfection studies.

Background: Provision of pasteurized donor human milk, as a bridge to mother’s own milk, is the standard of care for very low-birth-weight infants in hospital. The aim of this research was to confirm that Holder pasteurization (62.5°C for 30 min) would be sufficient to inactivate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in donated human milk samples. Methods: We spiked frozen milk samples from 10 donors to the Rogers Hixon Ontario Human Milk Bank with SARSCoV-2 to achieve a final concentration of 1 × 107 TCID50/mL (50% of the tissue culture infectivity dose per mL). We pasteurized samples using the Holder method or held them at room temperature for 30 minutes and plated serial dilutions on Vero E6 cells for 5 days. We included comparative controls in the study using milk samples from the same donors without addition of virus (pasteurized and unpasteurized) as well as replicates of Vero E6 cells directly inoculated with SARS-CoV-2. We reported cytopathic effects as TCID50/mL. Results: We detected no cytopathic activity in any of the SARS-CoV-2–spiked milk samples that had been pasteurized using the Holder method. In the SARSCoV-2–spiked milk samples that were not pasteurized but were kept at room temperature for 30 minutes, we observed a reduction in infectious viral titre of about 1 log. Interpretation: Pasteurization of human milk by the Holder method (62.5°C for 30 min) inactivates SARS-CoV-2. Thus, in the event that donated human milk contains SARS-CoV-2 by transmission through the mammary gland or by contamination, this method of pasteurization renders milk safe for consumption and handling by care providers. Trial registration: Chinese Clinical Trial Registry, No. ChiCTR2000031301.

Introduction: This study aims to determine the diagnostic value of IL-6, IL-8, IL-17, TNF-α and D-lactate levels in the cerebrospinal fluid (CSF) in nosocomial meningitis. Methods: CSF levels of cytokines and D-lactate were compared across 29 episodes who were diagnosed with nosocomial meningitis, 38 episodes with pleocytosis but without meningitis and 54 control subjects. Results: CSF levels of IL-6, IL-8, and D-lactate were higher in the group with nosocomial meningitis compared to the control group and to the group with pleocytosis without meningitis (p 440 pg/mL, the sensitivity and specificity were 55.17% and 94.74%, respectively. For IL-8 levels, when the threshold was considered to be >1249 pg/mL, the sensitivity and specificity were 44.83% and 84.21%, respectively. In the patients with nosocomial meningitis, when the threshold of D-lactate levels was considered to be >1.05µmol/mL, the sensitivity and specificity were found to be 75.86% and 63.16%, respectively. In the pleocytosis without meningitis CSF samples and in the CSF samples diagnosed with nosocomial meningitis, the highest AUC was calculated for triple combination model of IL-6, IL-8, and D-lactate levels (AUC= 0.801, p

SUMMARYSARS-CoV-2, depends on host cell components for replication, therefore the identification of virus-host dependencies offers an effective way to elucidate mechanisms involved in viral infection. Such host factors may be necessary for infection and replication of SARS-CoV-2 and, if druggable, presents an attractive strategy for anti-viral therapy. We performed genome wide CRISPR knockout screens in Vero E6 cells and 4 human cell lines including Calu-3, Caco-2, Hek293 and Huh7 to identify genetic regulators of SARS-CoV-2 infection. Our findings identified only ACE2, the cognate SARS-CoV-2 entry receptor, as a common host dependency factor across all cell lines, while all other host genes identified were cell line specific including known factors TMPRSS2 and CTSL. Several of the discovered host-dependency factors converged on pathways involved in cell signalling, lipid metabolism, immune pathways and chromatin modulation. Notably, chromatin modulator genes KMT2C and KDM6A in Calu-3 cells had the strongest impact in preventing SARS-CoV-2 infection when perturbed. Overall, the network of host factors that have been identified will be broadly applicable to understanding the impact of SARS-CoV-2 on human cells and facilitate the development of host-directed therapies.IN BRIEFSARS-CoV-2, depends on host cell components for infection and replication. Genome-wide CRISPR screens were performed in multiple human cell lines to elucidate common host dependencies required for SARS-CoV-2 infection. Only ACE2, the cognate SARS-CoV-2 entry receptor, was common amongst cell lines, while all other host genes identified were cell line specific, several of which converged on pathways involved in cell signalling, lipid metabolism, immune pathways, and chromatin modulation. Overall, a network of host factors was identified that will be broadly applicable to understanding the impact of SARS-CoV-2 on human cells and facilitate productive targeting of host genes and pathways.HIGHLIGHTS- Genome-wide CRISPR screens for SARS-CoV-2 in multiple human cell lines- Identification of wide-ranging cell-type dependent genetic dependencies for SARS-CoV-2 infection- ACE2 is the only common host factor identified across different cell types

SARS-CoV-2, the virus responsible for COVID-19, has caused a global pandemic. Antibodies can be powerful biotherapeutics to fight viral infections. Here, we use the human apoferritin protomer as a modular subunit to drive oligomerization of antibody fragments and transform antibodies targeting SARS-CoV-2 into exceptionally potent neutralizers. Using this platform, half-maximal inhibitory concentration (IC50) values as low as 9 × 10−14 M are achieved as a result of up to 10,000-fold potency enhancements compared to corresponding IgGs. Combination of three different antibody specificities and the fragment crystallizable (Fc) domain on a single multivalent molecule conferred the ability to overcome viral sequence variability together with outstanding potency and IgG-like bioavailability. The MULTi-specific, multi-Affinity antiBODY (Multabody or MB) platform thus uniquely leverages binding avidity together with multi-specificity to deliver ultrapotent and broad neutralizers against SARS-CoV-2. The modularity of the platform also makes it relevant for rapid evaluation against other infectious diseases of global health importance. Neutralizing antibodies are a promising therapeutic for SARS-CoV-2.

RESUME CONTEXTE: Le recours aux dons de lait maternel pasteurise est la norme de soins dans les hopitaux pour les nourrissons ayant un tres faible poids a la naissance, afin de faire le pont en attendant que les meres puissent allaiter leur enfant. Le but de cette etude etait de verifier si la pasteurisation a l’aide de la methode de Holder (a 62,5 °C pendant 30 min) serait suffisante pour inactiver le coronavirus du syndrome respiratoire aigu severe 2 (SRAS-CoV-2) dans des echantillons de lait maternel provenant de donneuses. METHODES: Nous avons inocule avec le SRAS-CoV-2 des echantillons de lait congeles provenant de 10 donneuses de la Rogers Hixon Ontario Human Milk Bank (la banque de lait maternel de l’Ontario) pour atteindre une concentration finale de 1 × 107 DICT50/mL (50 % de la dose infectante de la culture de tissus par mL). Les echantillons ont ete pasteurises a l’aide de la methode de Holder ou laisses a la temperature du laboratoire pendant 30 minutes, puis nous avons mis en culture des dilutions en serie sur des cellules Vero E6 durant 5 jours. Nous avons utilise des echantillons temoins dans cette etude, soit des echantillons de lait provenant des memes donneuses, auxquels le virus n’a pas ete ajoute (echantillons pasteurises et non pasteurises), de meme que des replicats de cellules Vero E6 directement inoculees avec le SRAS-CoV-2. Nous rapportons ici les effets cytopathologiques en DICT50/mL. RESULTATS: Nous n’avons detecte aucune activite cytopathologique dans l’ensemble des echantillons de lait contenant le SRAS-CoV-2 pasteurises a l’aide de la methode de Holder. Dans les echantillons contenant le SRASCoV-2 qui n’ont pas ete pasteurises, mais plutot laisses a la temperature du laboratoire pendant 30 minutes, nous avons observe une reduction du titre infectieux d’environ 1 log. INTERPRETATION: La pasteurisation du lait maternel a l’aide de la methode de Holder (a 62,5 °C pendant 30 min) inactive le SRAS-CoV-2. Ainsi, si du lait maternel provenant de donneuses contenait le virus a la suite d’une transmission par la glande mammaire ou d’une contamination, cette methode de pasteurisation rendrait le lait sans danger pour la consommation par le nourrisson et la manipulation par les travailleurs de la sante.

Saliva is an alternative biofluid to serum for detecting and monitoring IgG to SARS-CoV-2 spike and RBD antigens in COVID-19., While the antibody response to SARS-CoV-2 has been extensively studied in blood, relatively little is known about the antibody response in saliva and its relationship to systemic antibody levels. Here, we profiled by enzyme-linked immunosorbent assays (ELISAs) IgG, IgA and IgM responses to the SARS-CoV-2 spike protein (full length trimer) and its receptor-binding domain (RBD) in serum and saliva of acute and convalescent patients with laboratory-diagnosed COVID-19 ranging from 3–115 days post-symptom onset (PSO), compared to negative controls. Anti-SARS-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16–30 days PSO. Longitudinal analysis revealed that anti-SARS-CoV-2 IgA and IgM antibodies rapidly decayed, while IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. Lastly, IgG, IgM and to a lesser extent IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that serum and saliva IgG antibodies to SARS-CoV-2 are maintained in the majority of COVID-19 patients for at least 3 months PSO. IgG responses in saliva may serve as a surrogate measure of systemic immunity to SARS-CoV-2 based on their correlation with serum IgG responses.

While the antibody response to SARS-CoV-2 has been extensively studied in blood, relatively little is known about the mucosal immune response and its relationship to systemic antibody levels. Since SARS-CoV-2 initially replicates in the upper airway, the antibody response in the oral cavity is likely an important parameter that influences the course of infection, but how it correlates to the antibody response in serum is not known. Here, we profile by enzyme linked immunosorbent assays (ELISAs) IgG, IgA and IgM responses to the SARS-CoV-2 spike protein (full length trimer) and its receptor binding domain (RBD) in serum (n=496) and saliva (n=90) of acute and convalescent patients with laboratory-diagnosed COVID-19 ranging from 3–115 days post-symptom onset (PSO), compared to negative controls. Anti-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16–30 days PSO. Whereas anti-CoV-2 IgA and IgM antibodies rapidly decayed, IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. In a surrogate neutralization ELISA (snELISA), neutralization activity peaks by 31–45 days PSO and slowly declines, though a clear drop is detected at the last blood draw (105–115 days PSO). Lastly, IgG, IgM and to a lesser extent IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that systemic and mucosal humoral IgG antibodies are maintained in the majority of COVID-19 patients for at least 3 months PSO. Based on their correlation with each other, IgG responses in saliva may serve as a surrogate measure of systemic immunity.One Sentence SummaryIn this manuscript, we report evidence for sustained SARS-CoV-2-specific IgG and transient IgA and IgM responses both at the site of infection (mucosae) and systemically in COVID-19 patients over 3 months and suggest that saliva could be used as an alternative biofluid for monitoring IgG to SARS-CoV-2 spike and RBD antigens.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes Coronavirus Disease 2019 (COVID-19), has caused a global pandemic. Antibodies are powerful biotherapeutics to fight viral infections; however, discovery of the most potent and broadly acting clones can be lengthy. Here, we used the human apoferritin protomer as a modular subunit to drive oligomerization of antibody fragments and transform antibodies targeting SARS-CoV-2 into exceptionally potent neutralizers. Using this platform, half-maximal inhibitory concentration (IC50) values as low as 9 × 10−14 M were achieved as a result of up to 10,000-fold potency enhancements. Combination of three different antibody specificities and the fragment crystallizable (Fc) domain on a single multivalent molecule conferred the ability to overcome viral sequence variability together with outstanding potency and Ig-like in vivo bioavailability. This MULTi-specific, multi-Affinity antiBODY (Multabody; or MB) platform contributes a new class of medical countermeasures against COVID-19 and an efficient approach to rapidly deploy potent and broadly-acting therapeutics against infectious diseases of global health importance.

Background Clinical studies have long indicated that a pathological synergy exists between Neisseria gonorrhoeaeand HIV, with gonococcal infection increasing HIV transmission between HIV serodiscordant sexual partners. In trying to understand this association, we discovered that N. gonorrhoeae liberate a small molecule that stimulates HIV replication from latently infected CD4+ T cells. This led to our discovery that heptose phosphate (HP)-containing metabolites, 7-carbon phospho-sugars not produced by animals, serve as a molecular cue that bacteria are present in the tissues and elicit an NF-κB-dependent transcriptional response. Based upon these observations, this study aims to test the hypothesis that HP can function both to (i) drive the virus from latency and (ii) stimulate the antiviral response to work in synergy with available highly active antiretroviral therapies to cure HIV infection. Methods We have used a combination of cell line and primary human leukocyte-based models to test the effect of natural and synthetic analogues of HP to stimulate HIV from latency, both alone and in combination with potential latency reversing agents, and to understand their effect of HPs on different leukocytic populations that have potential to either promote or inhibit HIV infection. Results We show that HP has a superior combination of HIV latency reversal without toxicity often evident with conventional LRAs, and HP activity synergizes with other LRAs such that these can be administered at lower concentrations. Finally, we observed that HP stimulates primary human leukocytic responses with anti-viral potential. Conclusion Our findings suggest that HP-based agonists are a novel LRA capable of both driving HIV from latency and stimulating immune responses so as to help control the infection. By virtue of its synergy with other LRAs and clinically available anti-retroviral agents, this represents an enticing new avenue in ongoing efforts to develop a cure for established HIV infection. Disclosure No significant relationships.

Although our knowledge about Brucella virulence factors and the host response increase rapidly, the mechanisms of immune evasion by the pathogen and causes of chronic disease are still unknown. Here, we aimed to investigate the immunological factors which belong to CD8+ T cells and their roles in the transition of brucellosis from acute to chronic infection. Using miRNA microarray, more than 2000 miRNAs were screened in CD8+ T cells of patients with acute or chronic brucellosis and healthy controls that were sorted from peripheral blood with flow cytometry and validated through qRT-PCR. Findings were evaluated using GeneSpring GX (Agilent) 13.0 software and KEGG pathway analysis. Expression of two miRNAs were determined to display a significant fold change in chronic group when compared with acute or control groups. Both miRNAs (miR-126-5p and miR-4753-3p) were decreased (p 2). These miRNAs have the potential to be the regulators of CD8+ T cell-related marker genes for chronic brucellosis infections. The differentially expressed miRNAs and their predicted target genes are involved in MAPK signaling pathway, cytokine-cytokine receptor interactions, endocytosis, regulation of actin cytoskeleton, and focal adhesion indicating their potential roles in chronic brucellosis and its progression. It is the first study of miRNA expression analysis of human CD8+ T cells to clarify the mechanism of inveteracy in brucellosis.

The aim of this study was to investigate the immunological alterations that occur during the storage of erythrocyte suspensions which may lead to transfusion-related immunomodulation following allogeneic blood transfusion.One part of the erythrocyte suspensions obtained from donors was leucoreduced while the other part was not. The leucoreduced (LR) and non-leucoreduced (NL) erythrocyte suspensions were then further divided into three equal amounts which were stored for 0, 21 or 42 days prior to measurements, by enzyme-linked immunosorbent assays, of cytokine levels in their supernatants. T-helper (Th) lymphocyte subgroups and gene expression were analysed in the NL erythrocyte suspensions by flow cytometry and real-time polymerase chain reaction, respectively. Results were compared to those of storage day 0.By day 21, the number of Th2 cells had increased significantly and the numbers of Th1, Th22 and Treg cells had decreased significantly in the NL erythrocyte suspensions. On day 42 the numbers of Th2 and Treg cells in the NL suspensions were significantly increased while the number of Th1 cells was significantly decreased. The levels of transcription factors (TBX21, GATA3, and SPI.1) were significantly decreased on days 21 and 42, and AHR, FOXP3 and RORC2 levels were significantly increased on day 42 in NL erythrocyte suspensions. The decrease in interleukin-22 and increase in transforming growth factor-β levels found in NL erythrocyte suspensions on day 21 were statistically significant. Elevated levels of interleukin-17A were found in both LR and NL erythrocyte suspensions on day 42.Our results suggest that allogeneic leucocytes and cytokines may play significant roles in the development of transfusion-related immunomodulation.