Low Titers Research Articles

When to choose intraosseous access in prehospital trauma care: A registry-based study from the Israel Defense Forces

PurposePrompt vascular access is crucial for resuscitating bleeding trauma casualties in prehospital settings but achieving peripheral intravenous (PIV) access can be challenging during hemorrhagic shock due to peripheral vessel collapse. Early intraosseous (IO) device use is suggested as an alternative. This study examines injury characteristics and factors linked to IO access requirements. MethodsA registry-based cohort study from the Israel Defense Forces Trauma Registry (2010 – 2023) included trauma casualties receiving PIV or IO access prehospital. Casualties who had at least one documented PIV or IO access attempt were included, while those without vascular access were excluded. Casualties requiring both PIV and IO were classified in the IO group. Univariable logistic regression assessed the factors associated with IO access. Results were reported as odds ratios (OR) with 95% confidence intervals (CI), and significant difference was set at p < 0.05. ResultsOf 3462 casualties (86.3% male, the median age: 22 years), 3287 (94.9%) received PIV access and 175 (5.1%) had IO access attempts. In the IO group, 30.3% received freeze-dried plasma and 23.4% received low titer group O whole blood, significantly higher than that in the PIV group. Prehospital mortality was 35.0% in the IO group. Univariable analysis showed significant associations with IO access for increased PIV attempts (OR = 1.69; 95% CI: 1.34 – 2.13) and signs of profound shock (OR = 11.0; 95% CI: 5.5 – 23.3). ConclusionProfound shock signs are strongly linked to the need for IO access in prehospital settings with each successive PIV attempt increasing the likelihood of requiring IO conversion. IO access often accompanies low titer group O whole blood or freeze-dried plasma administration and higher prehospital mortality, indicating its use in emergent resuscitation situations. Early IO consideration is advised for trauma casualties with profound shock.

Persistent Splenic-Derived IgM Preferentially Recognize Factor VIIIA2 and C2 Domain Epitopes but Do Not Alter Antibody Production

The most significant treatment complication for patients with hemophilia A is the development of neutralizing immunoglobin G (IgG), termed inhibitors, against factor VIII (FVIII) which prevent FVIII replacement therapy. Low titers of FVIII-specific immunoglobin M (IgM) have been identified in hemophilia A patients with and without inhibitors, as well as healthy individuals. However, the duration and influence of IgM on the immune response to FVIII remains unclear. To characterize the binding interactions of persistently secreted FVIII-specific IgM in hemophilia A mice and assess their effect on IgG antibody development. Splenic-derived monoclonal antibodies (MAbs) from immunized FVIII knockout mice were isolated and purified using hybridoma technology. Binding interactions were assessed utilizing a novel fluid-phase ELISA and computational modeling with HADDOCK to account for weak IgM binding. Sixteen porcine cross-reactive and non-inhibitory FVIII-specific IgM MAbs were identified. RNA sequencing of FVIII-specific IgM revealed 13 unique VDJ/VJ sequences indicating derivation from 13 unique B cell clones. IgM demonstrated polyclonal and polyreactive binding to FVIII in vitro and in silico. Molecular docking studies with reconstructed IgM VDJ/VJ regions identified frequent IgM interactions with amino acid residues K376, T381, K437, R2215 or K2249 within the FVIII A2 and C2 domains. Injections of individual IgM prior to FVIII exposure and co-injection of FVIII/IgM immune complexes did not affect de novo FVIII antibody production. Persistent FVIII-specific IgM are polyclonal but preferentially bind the A2 and C2 domains and FVIII/IgM immune complex formation do not significantly alter inhibitor development.

High-Throughput Sequencing Methods for the Detection of Two Strawberry Viruses in Post-Entry Quarantine

High-throughput sequencing (HTS) technologies may be a useful tool for testing imported plant germplasm for multiple pathogens present in a sample, offering strain-generic detection not offered by most PCR-based assays. Metatranscriptomics (RNAseq) and tiled amplicon PCR (TA-PCR) were tested as HTS-based techniques to detect viruses present in low titres. Strawberry mottle virus (SMoV), an RNA virus, and strawberry vein banding virus (SVBV), a DNA virus, were selected for comparison of RNAseq and TA-PCR with quantitative PCR assays. RNAseq of plant ribosomal RNA-depleted samples of low viral titre was used to obtain datasets from 3 M to 120 M paired-end (PE) reads. RNAseq demonstrated PCR-like sensitivity, able to detect as few as 10 viral copies/µL when 60 million (M) PE reads were generated. The custom TA-PCR primer panels designed for each virus were successfully used to recover most of the reference genomes for each virus. Single- and multiple-target TA-PCR allowed the detection of viruses in samples with around 10 viral copies/µL with a minimum continuous sequence length recovery of 500 bp. The limit of detection of the HTS-based protocols described here is comparable to that of quantitative PCR assays. This work lays the groundwork for an increased flexibility in HTS detection of plant viruses.

Isolation and genetic characterization of canine adenovirus type 2 variant from raccoon dog (Nyctereutes procynoide koresis) in Republic of Korea

Canine adenovirus type 2 (CAV-2) is a common causative agent of respiratory disease in canines. There have been no reports of CAV-2 variants isolated from raccoon dogs. This study aims to investigate the biological and genetic characteristics of a novel Korean CAV-2 variant. Madin-Darby canine kidney cells were used to isolate the CAV-2 variant from 45 fecal swab samples. Diagnostic tools such as the cytopathic effect (CPE) assay, electron microscopy, polymerase chain reaction, and immunofluorescence and hemagglutination assays were used to confirm the presence of the CAV-2 isolate. A cross-virus neutralization assay was performed to verify the novelty of this CAV variant. Genetic analysis was performed using nucleotide sequences obtained through next-generation sequencing. The isolate was confirmed to be a CAV-2 variant based on the aforementioned methods and designated CAV2232. The number of bases in the fiber and E3 genes of CAV2232 were 1,626 and 414, respectively. Phylogenetic analysis of the fiber and E3 genes confirmed that CAV2232 was classified into a different clade from the known CAV-1 and CAV-2 strains. Mice inoculated with the CAV2232 vaccine developed high virus neutralization antibody titers of 1,024 (210) against CAV2232, while mice inoculated with CAV-1 and CAV-2 vaccines had low virus neutralization antibody titers of 12.9 (23.7) and 6.5 (22.7), respectively, against CAV2232. CAV2232 isolated from wild raccoon dog feces was classified as a novel CAV-2 variant. CAV2232 may therefore be used as an antigen for new vaccine development and serological investigations.

A Population-Based Study of SARS-CoV-2 IgG Antibody Responses to Vaccination in Manitoba.

Understanding variables that influence antibody responses to COVID-19 vaccination within a population can provide valuable information on future vaccination strategies. In this population-based study, we examined the antibody responses to COVID-19 vaccination in Manitoba using residual serum specimens collected between January 2021 and March 2022 (n = 20,365). Samples were tested for spike and nucleocapsid IgG against SARS-CoV-2 using clinically validated assays. We assessed the impacts of multiple factors on post-vaccination antibody titres including type of vaccine, age, sex, geographic location, number of doses received, and timing of vaccination. Our investigation demonstrated that vaccination with one dose of Moderna mRNA-1273 elicited higher anti-spike IgG titres overall compared to Pfizer BNT162b2 vaccination, while one dose of Pfizer BNT162b2 followed by a second dose of Moderna mRNA-1273 exhibited higher titres than two doses of Pfizer BNT162b2 or Moderna mRNA-1273, irrespective of age. Age and time post-vaccination had considerable effects on antibody responses, with older age groups exhibiting lower anti-spike IgG titres than younger ages, and titres of those vaccinated with Pfizer BNT162b2 waning faster than those vaccinated with Moderna mRNA-1273 or a combination of Pfizer BNT162b2 and Moderna mRNA-1273. Antibody titres did not appear to be affected by sex or geographic location. Our results identify how factors such as age and type of vaccine can influence antibody responses to vaccination, and how antibody titres wane over time. This information highlights the importance of tailoring vaccine regimens to specific populations, especially those at increased risk of severe COVID-19 and can be used to inform future vaccination strategies, scheduling of booster doses, and public health measures.

Isolation and characterization of the new Streptomyces phages Kamino, Geonosis, Abafar, and Scarif infecting a broad range of host species.

Streptomyces, a multifaceted genus of soil-dwelling bacteria belonging to the phylum Actinomycetota, features intricate phage-host interactions shaped by its complex life cycle and the synthesis of a diverse array of specialized metabolites. Here, we describe the isolation and characterization of four novel Streptomyces phages infecting a variety of different host species. While phage Kamino, isolated on Streptomyces kasugaensis, is predicted to be temperate and encodes a serine integrase in its genome, phages Geonosis (isolated on Streptomyces griseus) and Abafar and Scarif, isolated on Streptomyces albidoflavus, are virulent phages. Phages Kamino and Geonosis were shown to amplify well in liquid culture leading to a pronounced culture collapse already at low titers. Determination of the host range by testing >40 different Streptomyces species identified phages Kamino, Abafar, and Scarif as broad host-range phages. Overall, the phages described in this study expand the publicly available portfolio of phages infecting Streptomyces and will be instrumental in advancing the mechanistic understanding of the intricate antiviral strategies employed by these multicellular bacteria.IMPORTANCEThe actinobacterial genus Streptomyces is characterized by multicellular, filamentous growth and the synthesis of a diverse range of bioactive molecules. These characteristics also play a role in shaping their interactions with the most abundant predator in the environment, bacteriophages-viruses infecting bacteria. In this study, we characterize four new phages infecting Streptomyces. Out of those, three phages feature a broad host range infecting up to 15 different species. The isolated phages were characterized with respect to plaque and virion morphology, host range, and amplification in liquid culture. In summary, the phages reported in this study contribute to the broader collection of publicly available phages infecting Streptomyces, playing a crucial role in advancing our mechanistic understanding of phage-host interactions of these multicellular bacteria.

Investigating the 2023 MOGAD Criteria in Children and Adults With MOG-Antibody Positivity Within and Outside Attacks.

The 2023 criteria for myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) perform well in adults but have not been assessed in children. This prospective observational nationwide study includes children and adults with demyelinating syndromes or encephalitis, whose serum or CSF was found MOG-immunoglobulin G (IgG) positive at Institut d'Investigacions Biomèdiques August Pi i Sunyer-Hospital Clínic of Barcelona (Spain). Exclusion criteria were lack of clinical information and follow-up <1 year, and serum unavailable for antibody testing. The primary outcome was to assess the accuracy of the 2023 MOGAD criteria, using as gold standard the most plausible diagnosis after a follow-up >1 year. MOGAD criteria were retrospectively applied assessing core syndromes, supportive clinical-radiological features, and MOG-IgG titers. Patients tested ≤3 months of a disease attack (acute phase) or afterward (remission) were considered separately. The positive predictive value (PPV) of the criteria (true-positive [patients classified as MOGAD and MOGAD diagnosis last follow-up] divided by total positive [all patients classified as MOGAD]), and its 95% CI, was calculated with the Wilson procedure. A total of 257 patients (133 children) were included in the study (median age 15 years [interquartile range 6-38], 54% female). Among 202 patients assessed during a disease attack, 158 (78%) had high MOG-IgG serum titers, 36 (18%) low titers, and 8 (4%) antibodies only in CSF. No differences were identified between patients with high and low titers, but those with low titers were more likely to have an alternative diagnosis at last follow-up (2/36 [6%] vs 0/158, p = 0.012). Supportive features were present in 230 of 257 (89%) patients, regardless of age, MOG-IgG titers, and core syndromes except for optic neuritis in adults whose assessment with orbital MRI was not systematic. Overall, 240 of 257 (94%) patients were well classified by the MOGAD criteria (e.g., 236 eventually having MOGAD and 4 alternative diagnoses), and 17 were wrongly classified (e.g., 11 eventually having MOGAD and 6 alternative diagnoses). Although the criteria classified better during disease attacks than during remissions (187 [96%] vs 49 [89%] serum MOG-IgG-positive patients were well-classified, p = 0.038), the PPV was high in both settings (99% [95% CI 97-100] vs 98% [95% CI 89-100]). The 2023 MOGAD criteria correctly identified most children and adults with MOGAD. The highest accuracy occurred when they were applied during disease attacks. This study provides Class IV evidence that the 2023 MOGAD criteria accurately identify adults and children with MOGAD.

Cytotoxicity of Activator Expression in CRISPR-based Transcriptional Activation Systems.

CRISPR-based transcriptional activation (CRISPRa) has extensive research and clinical potential. Here, we show that commonly used CRISPRa systems can exhibit pronounced cytotoxicity. We demonstrate the toxicity of published and new CRISPRa vectors expressing the activation domains (ADs) of the transcription factors p65 and HSF1, components of the synergistic activation mediator (SAM) CRISPRa system. Based on our findings for the SAM system, we extended our studies to additional ADs and the p300 acetyltransferase core domain. We show that the expression of potent transcriptional activators in lentiviral producer cells leads to low lentiviral titers, while their expression in the transduced target cells leads to cell death. Using inducible lentiviral vectors, we could not identify an activator expression window for effective SAM-based CRISPRa without measurable toxicity. The toxicity of current SAM-based CRISPRa systems hinders their wide adoption in biomedical research and introduces selection bottlenecks that may confound genetic screens. Our results suggest that the further development of CRISPRa technology should consider both the efficiency of gene activation and activator toxicity.

Pharmacokinetics and pharmacodynamics of the factor XIa-inhibiting antibody osocimab in healthy male East Asian volunteers: Results from two phase 1 studies.

The pharmacokinetics, pharmacodynamics, immunogenicity, and safety of osocimab single doses in healthy Chinese and Japanese volunteers over 149 days were evaluated. Two phase 1 single-blinded, placebo-controlled studies with 27 Japanese and 50 Chinese participants were conducted. Osocimab was investigated with IV doses of 0.3, 1.25, and 2.5 mg/kg (Chinese study) and 0.3, 1.25, and 5.0 mg/kg (Japanese study), as well as SC doses of 3.0 and 6.0 mg/kg (Chinese study) and 6.0 mg/kg (Japanese study). The maximum plasma concentration was reached 1-3 h and 4-6 days after IV and SC administration, respectively. Osocimab exhibited a deviation from dose-proportional pharmacokinetics for AUC but not Cmax; higher doses had higher apparent clearance and disproportionately lower total exposure. A slightly lower exposure was observed in Japanese compared with Chinese volunteers after IV administration; conversely, relatively higher exposure in Japanese volunteers with SC dosing was identified. Osocimab was associated with a dose-dependent increase in activated partial thromboplastin time (aPTT). Maximal aPTT prolongations were observed 1-4 h and 2-6 days after IV and SC administration, respectively. Anti-drug antibodies of low titer were detected in 1/9 (11.1%) Japanese volunteers administered placebo and 26/40 (65.0%) Chinese volunteers administered osocimab. Adverse events were reported in 8/18 (44.4%) Japanese and 28/40 (70.0%) Chinese volunteers who received osocimab, as well as in 1/9 (11.1%) Japanese and 6/10 (60.0%) Chinese volunteers who received placebo. In conclusion, data did not suggest a clear dose-proportionality for osocimab within the investigated dose range. The effect of osocimab on aPTT was expected per its mechanism of action. Osocimab was generally well tolerated.

Energy Metabolism Enhance Perylenequinone Biosynthesis in Shiraia sp. Slf14 through Promoting Mitochondrial ROS Accumulation.

Perylenequinones (PQs) are important natural compounds that have been extensively utilized in recent years as agents for antimicrobial, anticancer, and antiviral photodynamic therapies. In this study, we investigated the molecular mechanisms regulating PQ biosynthesis by comparing Shiraia sp. Slf14 with its low PQ titer mutant, Slf14(w). The results indicated that the strain Slf14 exhibited a higher PQ yield, a more vigorous energy metabolism, and a more pronounced oxidation state compared to Slf14(w). Transcriptome analysis consistently revealed that the differences in gene expression between Slf14 and Slf14(w) are primarily associated with genes involved in redox processes and energy metabolism. Additionally, reactive oxygen species (ROS) were shown to play a crucial role in promoting PQ synthesis, as evidenced by the application of ROS-related inhibitors and promoters. Further results demonstrated that mitochondria are significant sources of ROS, which effectively regulate PQ biosynthesis in Shiraia sp. Slf14. In summary, this research revealed a noteworthy finding: the higher energy metabolism of the strain Slf14 is associated with increased intracellular ROS accumulation, which in turn triggers the activation and expression of gene clusters responsible for PQ synthesis.

Differing Transcriptomic Responses in High Titer versus Low Titer Aedes aegypti Mosquitoes after Oral Infection with Sindbis Virus.

Oral infection of mosquitoes by arboviruses often results in a large degree of variation in the amount of infectious virus between individual mosquitoes, even when the mosquitoes are from inbred laboratory strains. This variability in arbovirus load has been shown to affect virus transmissibility. Previously, our group described population genetic and specific infectivity differences between the virus populations found in high and low titer Aedes aegypti mosquitoes that had been orally infected with Sindbis virus (SINV). In this study, we sought to investigate whether there were also differences in transcriptomic response between these high and low titer mosquitoes. Results from the transcriptomic data analysis showed that more genes involved in antiviral activity, endopeptidase activity, and methyltransferase activity were upregulated in low titer mosquitoes than in high titer mosquitoes, relative to blood-fed controls. Meanwhile, genes involved in ion transport, energy metabolism, acetylation, glycosylation, lipid metabolism, and transport tended to be upregulated in high titer mosquitoes more than in low titer mosquitoes, relative to blood-fed mosquitoes. Overall, genes involved in antiviral activities tended to be upregulated in low titer mosquitoes while genes involved in proviral activities were mostly upregulated in high titer mosquitoes. This study has identified a number of candidate mosquito genes that are putatively associated with SINV titer variability after oral infection of Ae. aegypti, and these can now be investigated in order to ascertain their roles in virus replication and their contributions to determining vector competence.

Engineering ethanologenicity into the extremely thermophilic bacterium Anaerocellum (f. Caldicellulosiriuptor) bescii

The anaerobic bacterium Anaerocellum (f. Caldicellulosiruptor) bescii natively ferments the carbohydrate content of plant biomass (including microcrystalline cellulose) into predominantly acetate, H2, and CO2, and smaller amounts of lactate, alanine and valine. While this extreme thermophile (growth Topt 78 °C) is not natively ethanologenic, it has been previously metabolically engineered with this property, albeit initially yielding low solvent titers (∼15 mM). Herein we report significant progress on improving ethanologenicity in A. bescii, such that titers above 130 mM have now been achieved, while concomitantly improving selectivity by minimizing acetate formation. Metabolic engineering progress has benefited from improved molecular genetic tools and better understanding of A. bescii growth physiology. Heterologous expression of a mutated thermophilic alcohol dehydrogenase (AdhE) modified for co-factor requirement, coupled with bioreactor operation strategies related to pH control, have been key to enhanced ethanol generation and fermentation product specificity. Insights gained from metabolic modeling of A. bescii set the stage for its further improvement as a metabolic engineering platform.

Autoantibodies to ADAMTS13 in human immunodeficiency virus-associated thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal thrombotic microangiopathic disorder that can result from human immunodeficiency virus (HIV) infection. The pathogenesis involves a deficiency of the von Willebrand factor (vWF) cleaving protease ADAMTS13 (a disintegrin and metalloprotease with thrombospondin motifs member 13) and the presence of anti-ADAMTS13 autoantibodies. However, there is insufficient information regarding the epitope specificity and reactivity of these autoantibodies. This study aimed to perform epitope-mapping analysis to provide novel insights into the specific epitopes on ADAMTS13 domains affected by autoantibodies. The study analysed 59 frozen citrate plasma samples from HIV-associated TTP patients in South Africa, measuring ADAMTS13 activity using Technozyme® ADAMTS13 activity test, total immunoglobulin (Ig) M and IgA antibodies levels using ELISA kit and purifying IgG antibodies using NAb™ Protein G spin columns. A synthetic ADAMTS13 peptide library was used for epitope mapping. Overall, 90% of samples showed anti-ADAMTS13 IgG autoantibodies, with 64% of these antibodies being inhibitory, as revealed by mixing studies. Samples with ADAMTS13 antigen levels below 5% showed high anti-ADAMTS13 IgG autoantibody titres (≥50 IU/mL), whereas those with 5%-10% levels had low autoantibody titres (<50 IU/mL).The metalloprotease, cysteine-rich and spacer domains were 100% involved in binding anti-ADAMTS13 IgG antibodies, with 58% of samples containing antibodies binding to the C-terminal part of the ADAMTS13 disintegrin-like domain, indicating different pathogenic mechanisms. The metalloprotease, cysteine-rich and spacer domains are the primary targets for anti-ADAMTS13 IgG autoantibodies in patients with HIV-associated TTP. These findings suggest potential effects on the proteolytic activity of ADAMTS13, highlighting the complex nature of the pathogenic mechanisms involved.

COBRA N2 NA vaccines induce protective immune responses against influenza viral infection

ABSTRACT Influenza neuraminidase (NA) is a promising target for a broadly protective vaccine. In this study, the Computationally Optimized Broadly Reactive Antigen (COBRA) methodology was used to develop N2 NA vaccine candidates. The unique wild type (WT) N2 sequences of human and swine influenza strains isolated between 1957 and 2019 were used to design the COBRA N2-A NA vaccine, while the unique WT N2 sequences of human influenza strains isolated between 2000 and 2019 were used to design the COBRA N2-B NA vaccine. Sera collected from COBRA N2 NA vaccinated mice showed more broadly reactive antibody responses against a broad panel of H×N2 influenza virus strains than sera collected from mice vaccinated with WT N2 NA vaccines. Antibodies elicited by COBRA or WT N2 NA antigens cross react with recent human H3N2 influenza viruses from different clades, while the antibodies elicited by A/Switzerland/9715293/2013 hemagglutinin (HA) reacted with viruses from the same clade. Furthermore, mice vaccinated with COBRA N2-B NA vaccine had lower viral lung titers compared to mock vaccinated mice when challenged with human H3N2 influenza viruses. Thus, the COBRA N2 NA vaccines elicit broadly protective murine anti-NA antibodies against multiple strains across subtypes and the viral loads were significantly decreased in the lungs of the mice in the COBRA N2 NA vaccine groups, compared to the mice in the mock vaccinated group, indicating that the COBRA-based N2 subtype NA vaccines have a potential to be a component in a universal influenza vaccine.

The TIRS trial: Enrollment procedures and baseline characterization of a pediatric cohort to quantify the epidemiologic impact of targeted indoor residual spraying on Aedes-borne viruses in Merida, Mexico.

Aedes mosquito-borne viruses (ABVs) place a substantial strain on public health resources in the Americas. Vector control of Aedes mosquitoes is an important public health strategy to decrease or prevent spread of ABVs. The ongoing Targeted Indoor Residual Spraying (TIRS) trial is an NIH-sponsored clinical trial to study the efficacy of a novel, proactive vector control technique to prevent dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) infections in the endemic city of Merida, Yucatan, Mexico. The primary outcome of the trial is laboratory-confirmed ABV infections in neighborhood clusters. Despite the difficulties caused by the COVID-19 pandemic, by early 2021 the TIRS trial completed enrollment of 4,792 children aged 2-15 years in 50 neighborhood clusters which were allocated to control or intervention arms via a covariate-constrained randomization algorithm. Here, we describe the makeup and ABV seroprevalence of participants and mosquito population characteristics in both arms before TIRS administration. Baseline surveys showed similar distribution of age, sex, and socio-economic factors between the arms. Serum samples from 1,399 children were tested by commercially available ELISAs for presence of anti-ABV antibodies. We found that 45.1% of children were seropositive for one or more flaviviruses and 24.0% were seropositive for CHIKV. Of the flavivirus-positive participants, most were positive for ZIKV-neutralizing antibodies by focus reduction neutralization testing which indicated a higher proportion of participants with previous ZIKV than DENV infections within the cohort. Both study arms had statistically similar seroprevalence for all viruses tested, similar socio-demographic compositions, similar levels of Ae. aegypti infestation, and similar observed mosquito susceptibility to insecticides. These findings describe a population with a high rate of previous exposure to ZIKV and lower titers of neutralizing antibodies against DENV serotypes, suggesting susceptibility to future outbreaks of flaviviruses is possible, but proactive vector control may mitigate these risks.

The comparison of pathogenicity among SARS-CoV-2 variants in domestic cats

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been detected or isolated from domestic cats. It is unclear whether cats play an important role in the SARS-CoV-2 transmission cycle. In this study, we examined the susceptibility of cats to SARS-CoV-2, including wild type and variants, by animal experiments. Cats inoculated with wild type, gamma, and delta variants secreted a large amount of SARS-CoV-2 for 1 week after the inoculation from nasal, oropharyngeal, and rectal routes. Only 100 TCID50 of virus could infect cats and replicate well without severe clinical symptoms. In addition, one cat inoculated with wild type showed persistent virus secretion in feces for over 28 days post-inoculation (dpi). The titer of virus-neutralizing (VN) antibodies against SARS-CoV-2 increased from 11 dpi, reaching a peak at 14 dpi. However, the omicron variant could not replicate well in cat tissues and induced a lower titer of VN antibodies. It is concluded that cats were highly susceptible to SARS-CoV-2 infection, but not to the Omicron Variant, which caused the attenuated pathogenicity.

Use of low titer O whole blood in infants and young children undergoing cardiac surgery with cardiopulmonary bypass.

Low titer group O whole blood (LTOWB) is commonly used for severe bleeding in trauma patients. LTOWB may also benefit young children requiring cardiac surgery with cardiopulmonary bypass (CPB) at risk of severe bleeding. In this retrospective study, children <2 years old who underwent cardiac surgery with CPB were included. Comparisons were performed between those receiving component therapy (CT) versus those receiving LTOWB plus CT (LTOWB+CT). Outcomes included drainage tube (DT) output and total transfusion volumes. Optimization-based weighting was used for adjusted analyses between groups. There were 117 patients transfused with only CT and 127 patients transfused with LTOWB+CT. In the LTOWB+CT group, 66 were Group non-O and 61 were Group O. Total transfusion volumes given from the start of the operation until the first 24 h in the cardiac intensive care unit was a median (IQR) 41 (10, 93) mL/kg in the CT group and 48 (28, 77) mL/kg in the LTOWB+CT group, (p = .28). Median (IQR) DT output was 22 (15-32) in CT versus 22 (16-28) in LTOWB+CT groups, (p = .27). There were no differences in death, renal failure and a composite of death and renal failure between the two groups, but there were statistically fewer re-explorations for bleeding in the LTOWB+CT group (p < .001). The use of LTOWB appears to be safe in <2 years old undergoing cardiac surgery and may reduce re-explorations for severe bleeding. Large trials are needed to determine the efficacy and safety of LTOWB in this population with severe bleeding.

Intranasal parainfluenza virus-vectored vaccine expressing SARS-CoV-2 spike protein of Delta or Omicron B.1.1.529 induces mucosal and systemic immunity and protects hamsters against homologous and heterologous challenge.

The continuous emergence of new SARS-CoV-2 variants requires that COVID vaccines be updated to match circulating strains. We generated B/HPIV3-vectored vaccines expressing 6P-stabilized S protein of the ancestral, B.1.617.2/Delta, or B.1.1.529/Omicron variants as pediatric vaccines for intranasal immunization against HPIV3 and SARS-CoV-2 and characterized these in hamsters. Following intranasal immunization, these B/HPIV3 vectors replicated in the upper and lower respiratory tract and induced mucosal and serum anti-S IgA and IgG. B/HPIV3 expressing ancestral or B.1.617.2/Delta-derived S-6P induced serum antibodies that effectively neutralized SARS-CoV-2 of the ancestral and B.1.617.2/Delta lineages, while the cross-neutralizing potency of B.1.1.529/Omicron S-induced antibodies was lower. Despite the lower cross-neutralizing titers induced by B/HPIV3 expressing S-6P from B.1.1.529/Omicron, a single intranasal dose of all three versions of B/HPIV3 vectors was protective against matched or heterologous WA1/2020, B.1.617.2/Delta or BA.1 (B.1.1.529.1)/Omicron challenge; hamsters were protected from challenge virus replication in the lungs, while low levels of challenge virus were detectable in the upper respiratory tract of a small number of animals. Immunization also protected against lung inflammatory response after challenge, with mild inflammatory cytokine induction associated with the slightly lower level of cross-protection of WA1/2020 and B.1.617.2/Delta variants against the BA.1/Omicron variant. Serum antibodies elicited by all vaccine candidates were broadly reactive against 20 antigenic variants, but the antigenic breadth of antibodies elicited by B/HPIV3-expressed S-6P from the ancestral or B.1.617.2/Delta variant exceeded that of the S-6P B.1.1.529/Omicron expressing vector. These results will guide development of intranasal B/HPIV3 vectors with S antigens matching circulating SARS-CoV-2 variants.

Performance evaluation of four kits for the detection of neutralizing antibody against SARS-CoV-2 in human serum

To evaluate four novel SARS-CoV-2 neutralizing antibody assay kits' application in neutralizing antibodies of population. Questionnaires from the voluntary participating researchers and selected the qualified questionnaires to analyse. For negative and positive coincidence rate, four novel SARS-Cov-2 neutralization antibody assay kits were tested. For within-run and between-run Precision verification study, four serum samples with two high and two low titer neutralizing antibodies were used to analyse. Based on the questionnaires, 175 qualified samples were divided into two groups. (1) negative neutralizing antibodies group: 31 samples had not been infected with the novel SARS-Cov-2 nor received the vaccine within the past one year; (2) positive neutralizing antibodies group: 144 samples were infected by COVID-19. There was 28 negative and 3 positive neutralizing antibodies of the individuals among the 31 negative samples which based on the questionnaires. The negative rates of 28 negative individules tested by GenScript, Vazyme and Hygeianey were 82.14 %, 60.71 % and 17.85 %, while the positive rates of the 147 positive samples were 93.87 %, 95.23 % and 100 %. The within-run coefficient of variations (C·V) of PBNAs, GenScript, Vazyme and Hygeianey were 11.49 %, 9.12 %, 7.97 % and 7.48 %, while the between-run coefficient of variations (C·V) were 21.37 %, 14.21 %, 12.29 % and 11.78 %. Due to the large within-run and between-run coefficient of variations, PBNAs was not suitable for large-scale promotion, while ELISAs could be leveraged for routine monitoring the titer of neutralizing antibodies against SARS-CoV-2.

Potential Association between Shift Work and Serologic Response to Hepatitis B Vaccination among Manufacturing Workers in Republic of Korea.

(1) Background: Shift work can affect physical health and the immune system by altering the body's circadian rhythms. This study investigated the factors associated with the hepatitis B virus (HBV) vaccination response in manufacturing workers, classified by whether they engaged in shift work or not. (2) Methods: This retrospective observational study was conducted among adults employed at two manufacturing companies. Those with negative initial hepatitis B surface antibody (HBsAb) levels before vaccination and who subsequently received a three-dose series of HBV vaccine were enrolled. Hepatitis B surface antibodies were examined for 3 years after the first dose. The endpoint of this study was the failure of a seroprotective anti-HB response after vaccination (HBsAb < 10 mIU/mL). Binary logistic regression models were used to analyze factors associated with response failures. (3) Results: Of the 1103 eligible subjects, 337 (30.6%) were shift workers. The failure rate was numerically higher in the shift workers (9.2%) than in the non-shift workers (7.9%), without statistical significance (p = 0.405). However, after adjustment with the binary logistic regression models, the shift workers had a statistically significantly higher rate of response failures than the non-shift workers (odds ratio 2.87; 95% confidence interval 1.64-5.05, p < 0.001), as did males, older workers, those with a low initial anti-HB titer, those with a vitamin D deficiency, and current smokers. (4) Conclusions: Our findings suggest a possible association between shift work and the serologic responses to HBV vaccination. Novel strategies for vaccination should be considered for shift workers.