Lassa virus in novel hosts: insights into the epidemiology of lassa virus infections in southern Nigeria

Identification of the diverse animal hosts responsible for spill-over events from animals to humans is crucial for comprehending the transmission patterns of emerging infectious diseases, which pose significant public health risks. To better characterize potential animal hosts of Lassa virus (LASV), we assessed domestic and non-domestic animals from 2021-2022 in four locations in southern Nigeria with reported cases of Lassa fever (LF). Birds, lizards, and domestic mammals (dogs, pigs, cattle and goats) were screened using RT-qPCR, and whole genome sequencing was performed for lineage identification on selected LASV positive samples. Animals were also screened for exposure to LASV by enzyme-linked immunosorbent assay (ELISA). Among these animals, lizards had the highest positivity rate by PCR. Genomic sequencing of samples in most infected animals showed sub-lineage 2 g of LASV. Seropositivity was highest among cattle and lowest in pigs. Though the specific impact these additional hosts may have in the broader virus-host context are still unknown - specifically relating to pathogen diversity, evolution, and transmission - the detection of LASV in non-rodent hosts living in proximity to confirmed human LF cases suggests their involvement during transmission as potential reservoirs. Additional epidemiological data comparing viral genomes from humans and animals, as well as those circulating within the environment will be critical in understanding LASV transmission dynamics and will ultimately guide the development of countermeasures for this zoonotic health threat.

Clinical, molecular, and drug resistance epidemiology of HIV in Jordan, 2019-2021: a national study

BACKGROUND

Limited epidemiologic studies have been conducted in Jordan describing the HIV epidemic. This study aimed to address this gap to inform HIV prevention and control.

METHODS

A nationally-representative cross-sectional study was conducted among adults living with HIV in Jordan. Laboratory testing included HIV viral load and next-generation-sequencing-based clinical genotype. Log-binomial regression estimated risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

Among 231 (70%) participants, most were male (184/80%), and from Jordan (217/94%). Among 188 treatment-experienced-participants (>6 months), 165 (88%) were virally suppressed. High level resistance was most frequent against nucleoside reverse transcriptase inhibitor (13/81%), and integrase-strand transfer inhibitor (INSTI) (10/62%) drugs among viremic (≥1,000 HIV copies/mL) treatment-experienced participants with drug resistant mutations (DRMs, n=16). Common HIV subtypes (n=43) were B (6/14%), A1 (5/12%), and CRF01_AE (5/12%); additionally, novel recombinant forms were detected. In multivariate analysis, independently higher risk for late diagnosis (n=49) was observed with diagnosis through blood donation (vs check-up: RR 2·20, 95%CI 1·16-4·17) and earlier time-period of diagnosis (1986-2014 vs 2015-2021: RR 2·87, 95%CI 1·46-5·62).

CONCLUSIONS

Late diagnosis and INSTI resistance endanger national HIV prevention and treatment in Jordan - high-level resistance to INSTI suggests therapeutic drug monitoring is needed for treatment efficacy, and conservation of treatment options.

Safety, tolerability, and immunogenicity of the chimpanzee adenovirus type 3-vectored Marburg virus (cAd3-Marburg) vaccine in healthy adults in the USA: a first-in-human, phase 1, open-label, dose-escalation trial

BACKGROUND

WHO has identified Marburg virus as an emerging virus requiring urgent vaccine research and development, particularly due to its recent emergence in Ghana. We report results from a first-in-human clinical trial evaluating a replication-deficient recombinant chimpanzee adenovirus type 3 (cAd3)-vectored vaccine encoding a wild-type Marburg virus Angola glycoprotein (cAd3-Marburg) in healthy adults.

METHODS

We did a first-in-human, phase 1, open-label, dose-escalation trial of the cAd3-Marburg vaccine at the Walter Reed Army Institute of Research Clinical Trials Center in the USA. Healthy adults aged 18-50 years were assigned to receive a single intramuscular dose of cAd3-Marburg vaccine at either 1 × 1010 or 1 × 1011 particle units (pu). Primary safety endpoints included reactogenicity assessed for the first 7 days and all adverse events assessed for 28 days after vaccination. Secondary immunogenicity endpoints were assessment of binding antibody responses and T-cell responses against the Marburg virus glycoprotein insert, and assessment of neutralising antibody responses against the cAd3 vector 4 weeks after vaccination. This study is registered with ClinicalTrials.gov, NCT03475056.

FINDINGS

Between Oct 9, 2018, and Jan 31, 2019, 40 healthy adults were enrolled and assigned to receive a single intramuscular dose of cAd3-Marburg vaccine at either 1 × 1010 pu (n=20) or 1 × 1011 pu (n=20). The cAd3-Marburg vaccine was safe, well tolerated, and immunogenic. All enrolled participants received cAd3-Marburg vaccine, with 37 (93%) participants completing follow-up visits; two (5%) participants moved from the area and one (3%) was lost to follow-up. No serious adverse events related to vaccination occurred. Mild to moderate reactogenicity was observed after vaccination, with symptoms of injection site pain and tenderness (27 [68%] of 40 participants), malaise (18 [45%] of 40 participants), headache (17 [43%] of 40 participants), and myalgia (14 [35%] of 40 participants) most commonly reported. Glycoprotein-specific antibodies were induced in 38 (95%) of 40 participants 4 weeks after vaccination, with geometric mean titres of 421 [95% CI 209-846] in the 1 × 1010 pu group and 545 [276-1078] in the 1 × 1011 pu group, and remained significantly elevated at 48 weeks compared with baseline titres (39 [95% CI 13-119] in the 1 ×1010 pu group and 27 [95-156] in the 1 ×1011 pu group; both p<0·0001). T-cell responses to the glycoprotein insert and neutralising responses against the cAd3 vector were also increased at 4 weeks after vaccination.

INTERPRETATION

This first-in-human trial of this cAd3-Marburg vaccine showed the agent is safe and immunogenic, with a safety profile similar to previously tested cAd3-vectored filovirus vaccines. 95% of participants produced a glycoprotein-specific antibody response at 4 weeks after a single vaccination, which remained in 70% of participants at 48 weeks. These findings represent a crucial step in the development of a vaccine for emergency deployment against a re-emerging pathogen that has recently expanded its reach to new regions.

FUNDING

National Institutes of Health.

Virological and Serological Assessment of US Army Trainees Isolated for Coronavirus Disease 2019

BACKGROUND

Laboratory screening for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a key mitigation measure to avoid the spread of infection among recruits starting basic combat training in a congregate setting. Because viral nucleic acid can be detected persistently after recovery, we evaluated other laboratory markers to distinguish recruits who could proceed with training from those who were infected.

METHODS

Recruits isolated for coronavirus disease 2019 (COVID-19) were serially tested for SARS-CoV-2 subgenomic ribonucleic acid (sgRNA), and viral load (VL) by reverse-transcriptase polymerase chain reaction (RT-PCR), and for anti- SARS-CoV-2. Cluster and quadratic discriminant analyses of results were performed.

RESULTS

Among 229 recruits isolated for COVID-19, those with a RT-PCR cycle threshold >30.49 (sensitivity 95%, specificity 96%) or having sgRNA log10 RNA copies/mL <3.09 (sensitivity and specificity 96%) at entry into isolation were likely SARS-CoV-2 uninfected. Viral load >4.58 log10 RNA copies/mL or anti-SARS-CoV-2 signal-to-cutoff ratio <1.38 (VL: sensitivity and specificity 93%; anti-SARS-CoV-2: sensitivity 83%, specificity 79%) had comparatively lower sensitivity and specificity when used alone for discrimination of infected from uninfected.

CONCLUSIONS

Orthogonal laboratory assays used in combination with RT-PCR may have utility in determining SARS-CoV-2 infection status for decisions regarding isolation.

Serological and RT-PCR Surveillance for COVID-19 in an Asymptomatic US Army Trainee Population

BACKGROUND

Significant variability exists in the application of infection control policy throughout the US Army initial entry training environment. To generate actionable information for the prevention of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/coronavirus disease 2019 (COVID-19) transmission among new recruits, active enhanced surveillance was conducted for evidence of and exposure to SARS-CoV-2/COVID-19.

METHODS

We serially tested recruits with a reverse transcriptase polymerase chain reaction (RT-PCR) COVID-19 and/or total antibody to SARS-CoV-2 tests at days 0, 14, and week 10 upon arrival for basic combat training at a location in the Southern United States.

RESULTS

Among 1403 recruits who were enrolled over a 6-week period from August 25 through October 11, 2020, 84 recruits tested positive by RT-PCR, with more than half (55%, 46/84) testing positive at arrival and almost two-thirds (63%, 53/84) also testing seropositive at arrival. Similarly, among an overall 146 recruits who tested seropositive for SARS-CoV-2 during the period of observation, a majority (86%) tested seropositive at arrival; no hospitalizations were observed among seropositive recruits, and antibody response increased at week 10.

CONCLUSIONS

These findings that suggest serological testing may complement current test-based measures and provide another tool to incorporate in COVID-19 mitigation measures among trainees in the US Army.

Maternally Acquired Zika Antibodies Enhance Dengue Disease Severity in Mice

Antibody (Ab)-dependent enhancement can exacerbate dengue virus (DENV) infection due to cross-reactive Abs from an initial DENV infection, facilitating replication of a second DENV. Zika virus (ZIKV) emerged in DENV-endemic areas, raising questions about whether existing immunity could affect these related flaviviruses. We show that mice born with circulating maternal Abs against ZIKV develop severe disease upon DENV infection. Compared with pups of naive mothers, those born to ZIKV-immune mice lacking type I interferon receptor in myeloid cells (LysMCre⁺Ifnar1^fl/fl) exhibit heightened disease and viremia upon DENV infection. Passive transfer of IgG isolated from mice born to ZIKV-immune mothers resulted in increased viremia in naive recipient mice. Treatment with Abs blocking inflammatory cytokine tumor necrosis factor linked to DENV disease or Abs blocking DENV entry improved survival of DENV-infected mice born to ZIKV-immune mothers. Thus, the maternal Ab response to ZIKV infection or vaccination might predispose to severe dengue disease in infants.

A new paradigm for predicting risk of Torsades de Pointes during drug development: Commentary on: "Improved prediction of drug-induced Torsades de Pointes through simulations of dynamics and machine learning algorithms"

Drug-induced long QT syndrome (diLQTS) is a clinical entity in which administration of a drug produces marked prolongation of the QT interval on the ECG. DiLQTS places a patient at risk of developing Torsades de Pointes (TdP), a malignant polymorphic ventricular tachycardia associated with arrhythmic sudden cardiac death (SCD). In addition to diLQTS, other clinical risk factors for TdP include female gender, bradycardia, electrolyte disturbances, recent conversion to normal (sinus) rhythm, and congenital LQTS.

Phospholamban ablation rescues the enhanced propensity to arrhythmias of mice with CaMKII-constitutive phosphorylation of RyR2 at site S2814

KEY POINTS

Mice with Ca(2+) -calmodulin-dependent protein kinase (CaMKII) constitutive pseudo-phosphorylation of the ryanodine receptor RyR2 at Ser2814 (S2814D(+/+) mice) exhibit a higher open probability of RyR2, higher sarcoplasmic reticulum (SR) Ca(2+) leak in diastole and increased propensity to arrhythmias under stress conditions. We generated phospholamban (PLN)-deficient S2814D(+/+) knock-in mice by crossing two colonies, S2814D(+/+) and PLNKO mice, to test the hypothesis that PLN ablation can prevent the propensity to arrhythmias of S2814D(+/+) mice. PLN ablation partially rescues the altered intracellular Ca(2+) dynamics of S2814D(+/+) hearts and myocytes, but enhances SR Ca(2+) sparks and leak on confocal microscopy. PLN ablation diminishes ventricular arrhythmias promoted by CaMKII phosphorylation of S2814 on RyR2. PLN ablation aborts the arrhythmogenic SR Ca(2+) waves of S2814D(+/+) and transforms them into non-propagating events. A mathematical human myocyte model replicates these results and predicts the increase in SR Ca(2+) uptake required to prevent the arrhythmias induced by a CaMKII-dependent leaky RyR2.

ABSTRACT

Mice with constitutive pseudo-phosphorylation at Ser2814-RyR2 (S2814D(+/+) ) have increased propensity to arrhythmias under β-adrenergic stress conditions. Although abnormal Ca(2+) release from the sarcoplasmic reticulum (SR) has been linked to arrhythmogenesis, the role played by SR Ca(2+) uptake remains controversial. We tested the hypothesis that an increase in SR Ca(2+) uptake is able to rescue the increased arrhythmia propensity of S2814D(+/+) mice. We generated phospholamban (PLN)-deficient/S2814D(+/+) knock-in mice by crossing two colonies, S2814D(+/+) and PLNKO mice (SD(+/+) /KO). SD(+/+) /KO myocytes exhibited both increased SR Ca(2+) uptake seen in PLN knock-out (PLNKO) myocytes and diminished SR Ca(2+) load (relative to PLNKO), a characteristic of S2814D(+/+) myocytes. Ventricular arrhythmias evoked by catecholaminergic challenge (caffeine/adrenaline) in S2814D(+/+) mice in vivo or programmed electric stimulation and high extracellular Ca(2+) in S2814D(+) /(-) hearts ex vivo were significantly diminished by PLN ablation. At the myocyte level, PLN ablation converted the arrhythmogenic Ca(2+) waves evoked by high extracellular Ca(2+) provocation in S2814D(+/+) mice into non-propagated Ca(2+) mini-waves on confocal microscopy. Myocyte Ca(2+) waves, typical of S2814D(+/+) mice, could be evoked in SD(+/+) /KO cells by partially inhibiting SERCA2a. A mathematical human myocyte model replicated these results and allowed for predicting the increase in SR Ca(2+) uptake required to prevent the arrhythmias induced by a Ca(2+) -calmodulin-dependent protein kinase (CaMKII)-dependent leaky RyR2. Our results demonstrate that increasing SR Ca(2+) uptake by PLN ablation can prevent the arrhythmic events triggered by SR Ca(2+) leak due to CaMKII-dependent phosphorylation of the RyR2-S2814 site and underscore the benefits of increasing SERCA2a activity on SR Ca(2+) -triggered arrhythmias.

Molecular mechanisms of loss of beta 2-microglobulin expression in drug-resistant breast cancer sublines and its involvement in drug resistance

In this study, we investigated the mechanism of the loss or decreased expression of beta 2-microglobulin (beta 2m) in several drug-resistant sublines of MCF-7 and in a doxorubicin (DOX)-resistant variant of the T-47D breast cancer cell line. beta 2m protein and RNA are not expressed in highly metastatic, multidrug-resistant MCF-7/Adr cells with high resistance to DOX. Nuclear run-on transcription and RNA stability assays demonstrate that while beta 2m in MCF-7/Adr cells is transcribed, its mRNA is rapidly degraded after synthesis in these cells, indicating that it is controlled by post-transcriptional mechanisms. We also show that an MCF-7 subline (MCF-7/Adr-5) expressing a very low level of resistance to DOX has a decreased level of beta 2m expression. Treatment with actinomycin D revealed that the half-life of beta 2m mRNA in MCF-7 and MCF-7/Adr-5 cell lines was comparable. Nuclear run-on transcription analysis revealed a decreased rate of beta2m transcription in MCF-7/Adr-5 cells compared to that in MCF-7 cells. Moreover, beta 2m mRNA remained undetectable in MCF-7/Adr cells following cycloheximide treatment. However, in MCF-7 cells, increased beta 2m mRNA was observed after 12 h, and a similar level of increased mRNA expression was observed after 36 h of cycloheximide treatment in MCF-7/Adr-5 cells; these results suggest that one of the mechanisms controlling beta 2m mRNA expression might be a negative regulatory protein in MCF-7/Adr-5 cells. Analysis of the beta 2m status of other drug-resistant MCF-7 sublines revealed that deregulation of beta 2m is not limited to DOX resistance, but can also be detected in cells selected for resistance to mAMSA and DOX-verapamil. In addition, our data show that reduced beta 2m expression correlates with the decreased levels of estrogen receptor (ER) expression in the DOX-resistant MCF-7/Adr and T-47D/Adr-4 human breast cell lines. Furthermore, we provide evidence that the partial inhibition of beta 2m by antisense RNA results in 2-3-fold decreased sensitivity of MCF-7 cells to DOX and mAMSA. Moreover, the addition of exogenous beta 2m protein near its physiological human serum concentration can modulate the DOX sensitivity of the MCF-7 antisense beta 2m and control transfectants. Therefore, these results indicate that lost or decreased beta 2m expression is involved in the development of the drug-resistant phenotype and correlates with the loss of ER in human breast cancer cell lines.

Co-ordinated over-expression of the MRP and gamma-glutamylcysteine synthetase genes, but not MDR1, correlates with doxorubicin resistance in human malignant mesothelioma cell lines

While human malignant mesothelioma is extremely resistant to chemotherapy, its intrinsic resistance mechanisms remain largely unknown. In this study, we used normal human mesothelial cells and 5 human mesothelioma cell lines not previously exposed to chemotherapeutic agents to demonstrate that the mRNA for the multidrug resistance-associated protein (MRP) and gamma-glutamylcysteine synthetase (gamma-GCSh) heavy subunit genes, but not the P-glycoprotein (MDR1) gene, are co-ordinately over-expressed in mesothelioma cell lines. Expression of MRP as detected with an anti-MRP antibody correlated with decreased doxorubicin accumulation and resistance of mesothelioma cells to this drug. Our results strongly suggest roles for MRP and gamma-GCSh in chemoresistance in mesotheliomas.