Biology subjects

Duprex, W. P.

Publications and source records attributed to Duprex, W. P..

16 recordsLinked to original sources

bioRxiv2026

Oropouche virus causes acute hepatitis in mice controlled by Type I interferons

Oropouche virus (OROV), a member of the Peribunyaviridae family endemic to South America, is a current public health threat. The recent OROV outbreak driven by a novel reassortant has caused a dramatic increase in cases in 2024 (13,785 in Brazil, versus only 261 from 2015-2022) with sustained levels of transmission in 2025. Previously underreported outcomes have been recognized including miscarriage, microcephaly, encephalitis, and death. OROV lethality in humans has been attributed to severe coagulopathy with liver involvement, and epidemiological data suggests acute hepatitis occurs in mild cases of Oropouche fever, highlighting the underrecognized role of the liver in OROV pathogenesis. We present two discrete mouse models of OROV hepatic disease -- a lethal model that recapitulates the severe coagulopathy seen in fatal human cases and a model of self-resolving acute hepatitis which recapitulates mild human disease. OROV causes focal hepatic necrosis in mice, which progresses to massive necrosis and death when the Type I interferon receptor is antagonized. Additionally, we found a contemporary OROV isolate is less pathogenic in mice than a historic prototypical strain. These studies enhance our understanding of OROV pathogenesis and pave the way for potential therapeutic development and evaluation. ImportanceThe disease burden of Oropouche fever has been underrecognized and underreported, as highlighted by the increased testing seen in the ongoing outbreak. Specifically, the role of the liver in Oropouche virus pathogenesis has been neglected. Given the ongoing outbreak and increase in severe disease manifestations, there is a present need to understand Oropouche virus pathogenesis and test potential therapeutics. The mouse models of Oropouche-induced hepatitis presented here provide a means to understand how Oropouche virus causes liver damage in both a lethal and sublethal context. These models will be useful for the preclinical evaluation of vaccines and therapeutic treatments. Additionally, we compare the pathogenicity of a historical Oropouche virus isolate to a contemporary human isolate in a lethal mouse model. This represents an additional step towards understanding whether the circulating Oropouche virus isolates are uniquely more pathogenic or if increased testing has highlighted previously unreported outcomes.

microbiology↗

bioRxiv2025

Acute induction of IFNα is responsible for the attenuation of the live measles vaccine

The live-attenuated measles vaccine (LAMV) protects against measles in a safe, efficacious and durable manner. However, the mechanism by which LAMV is attenuated is not well understood, contributing to the increased vaccine hesitancy that has caused a worldwide resurgence of measles. Here, we provide a molecular model of attenuation that implicates increased host innate immune responses and increased LAMV susceptibility to those responses. Our study leverages both in vitro and in vivo models of infection to find that acute induction of innate immunity in immune cells is the critical determinant of LAMV attenuation. We show that LAMV, in contrast to pathogenic wild type measles virus (MeV), causes a strong IFN response in primary human peripheral blood mononuclear cells, which restricts viral replication and spread in a post-entry manner. LAMV can enter, transcribe viral mRNA and translate viral proteins in immune cells, but is not able to form infectious particles and spread from cell to cell. Specifically, we find that mutations conserved across LAMV strains in the P/V/C and H genes are responsible for the induction of IFN and the restriction of infectious virus production. In PBMC cultures and in rhesus macaques, LAMV infection also results in the acute induction of proinflammatory cytokines that likely play a role in the immunogenicity of the vaccine. Overall, our study provides a virological and immunological framework for LAMV attenuation which can be leveraged in repurposing the LAMV backbone and in future vaccine design.

microbiology↗

bioRxiv2025

Deletion of the Envelope gene attenuates SARS-CoV-2 infection by altered Spike localization and increased cell-to-cell transmission

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a highly transmissible acute respiratory infection that can result in severe pneumonia and death. Many details of SARS-CoV-2 infection are not fully understood, including the cell biology and host-virus interactions involved in coronavirus assembly and release, in which the Envelope (E) structural protein is instrumental. Deletion of E in other coronaviruses has been shown previously to either attenuate or abrogate infection. To determine the role of E on SARS-CoV-2 virus production and infectivity, we produced reporter SARS-CoV-2 with or without the E gene deleted using a bacterial artificial chromosome. Replication of {delta}E SARS-CoV-2 was attenuated in Vero E6 cells expressing human ACE2 and TMPRSS2 and in human epithelial cell lines. Electron and immunofluorescence microscopy and virology assays showed that {delta}E SARS-CoV-2 increased cell surface expression of Spike (S) glycoprotein, leading to reduced S incorporation into {delta}E SARS-CoV-2 particles and promotion of increased cell-to-cell transmission that evades neutralizing antibody inhibition. Trans-complementation of E partially rescued {delta}E SARS-CoV-2 S incorporation and restored cell-free transmission. In addition to validating the role of E in retention of S in the ER-Golgi intermediate complex (ERGIC), our results showed that a lack of E led to reorganization of the ERGIC and Golgi during SARS-CoV-2 infection. Improved understanding of E in SARS-CoV-2 replication and host pathogenesis may help development of novel therapeutics.

microbiology↗

bioRxiv2025

Origins and evolutionary trajectories of morbilliviruses in Neotropical bats

Bats are important reservoirs of paramyxoviruses, yet their role in the evolutionary origins of morbilliviruses like measles and rinderpest viruses remains unclear. Investigating wild bats (38/1,629 RT-PCR positive) and non-human primates (NHP, 13/1,370 RT-PCR-positive) from Latin America coupled with data mining, we identified six divergent morbilliviruses. High morbillivirus concentrations in bat organs and morbillivirus RNA staining in NHP livers suggested systemic infection. Of 117 vampire bats, 35.9% had neutralizing antibodies against a primary vampire bat morbillivirus isolate, suggesting frequent survived infections. Usage of bat, but not human, CD150 for cell entry and partial cross-neutralization of bat-associated morbillivirus by heterologous sera suggested conserved entry and antigenicity. Macro-evolutionary reconstructions revealed a predominant role of Neotropical bats during morbilliviral diversification, including bat-associated host shifts into Mexican pigs and Brazilian NHPs. These data argue for increased surveillance, experimental risk assessments, vaccine development, and intervention strategies to cease future outbreaks of previously reservoir-bound morbilliviruses.

microbiology↗

bioRxiv2024

Pre-existing H1N1 immunity reduces severe disease with bovine H5N1 influenza virus

The emergence of highly pathogenic H5N1 avian influenza in dairy cattle herds across the United States has caused multiple mild human infections. There is an urgent need to understand the risk of spillover into humans. Here, we show that pre-existing immunity from the 2009 H1N1 pandemic influenza virus provided protection from mortality and severe clinical disease to ferrets intranasally infected with bovine H5N1. H1N1 immune ferrets exhibited a differential tissue tropism with little bovine H5N1 viral dissemination to organs outside the respiratory tract and significantly less H5N1 virus found in nasal secretions and the respiratory tract. Additionally, ferrets with H1N1 prior immunity produced antibodies that cross-reacted with H5N1 neuraminidase protein. Taken together, these results suggest that mild disease in humans may be linked to prior immunity to human seasonal influenza viruses.

microbiology↗

bioRxiv2024

Characterization of neural infection by Oropouche orthobunyavirus

Oropouche fever is a re-emerging global viral threat caused by infection with Oropouche orthobunyavirus (OROV). While disease is generally self-limiting, historical and recent reports of neurologic involvement highlight the importance of understanding the neuropathogenesis of OROV. In this study, we characterize viral replication kinetics in neurons and microglia derived from immortalized, primary, and induced pluripotent stem cell-derived cells, which are all permissive to infection. We demonstrate that ex vivo rat brain slice cultures can be infected by OROV and produce antiviral cytokines and chemokines, including IL-6, TNF- and IFN-{beta}, which introduces an additional model to study viral kinetics in the central nervous system. These findings provide additional insight into OROV neuropathogenesis and in vitro modeling strategies for a newly re-emerging arbovirus.

microbiology↗

bioRxiv2022

Targeting Spike Glycans to Inhibit SARS-CoV2 Viral Entry

SARS-CoV-2 Spike harbors glycans which function as ligands for lectins. Therefore, it should be possible to exploit lectins to target SARS-CoV-2 and inhibit cellular entry by binding glycans on the Spike protein. Burkholderia oklahomensis agglutinin (BOA) is an antiviral lectin that interacts with viral glycoproteins via N-linked high mannose glycans. Here, we show that BOA binds to the Spike protein and is a potent inhibitor of SARS-CoV-2 viral entry at nanomolar concentrations. Using a variety of biophysical tools, we demonstrate that the interaction is avidity driven and that BOA crosslinks the Spike protein into soluble aggregates. Furthermore, using virus neutralization assays, we demonstrate that BOA effectively inhibits all tested variants of concern as well as SARS-CoV 2003, establishing that glycan-targeting molecules have the potential to be pan-coronavirus inhibitors.

biochemistry↗

bioRxiv2021

Molecular assembly of measles and Nipah virus: specific lipid binding drives conformational change and matrix polymerization

Measles virus, Nipah virus, and multiple other paramyxoviruses cause disease outbreaks in humans and animals worldwide. The paramyxovirus matrix (M) protein mediates virion assembly and budding from host cell membranes. M is thus a key target for antivirals, but few high-resolution structures of paramyxovirus M are available, and we lack the clear understanding of how viral M proteins interact with membrane lipids to mediate viral assembly and egress needed to guide antiviral design. Here, we reveal that M proteins associate with phosphatidylserine and phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) at the plasma membrane. Using X-ray crystallography, electron microscopy, and molecular dynamics we demonstrate that PI(4,5)P2 binding induces conformational and electrostatic changes in the M protein surface that trigger membrane deformation, matrix layer polymerization, and virion assembly.

microbiology↗

bioRxiv2021

Sustained replication of synthetic canine distemper virus defective genomes in vitro and in vivo

Defective interfering (DI) genomes restrict viral replication and induce type-I interferon. Since DI genomes have been proposed as vaccine adjuvants or therapeutic antiviral agents, it is important to understand their generation, delineate their mechanism of action, develop robust production capacities, assess their safety and in vivo longevity and determine their long-term effects. To address this, we generated a recombinant (r) canine distemper virus (CDV) from an entirely synthetic molecular clone designed using the genomic sequence from a clinical isolate obtained from a free-ranging raccoon with distemper. rCDV was serially passaged in vitro to identify DI genomes that naturally arise during rCDV replication. Defective genomes were identified by Sanger and next-generation sequencing techniques and predominant genomes were synthetically generated and cloned into T7-driven plasmids. Fully encapsidated DI particles (DIPs) were then generated using a rationally attenuated rCDV as a producer virus to drive DI genome replication. We demonstrate these DIPs interfere with rCDV replication in a dose-dependent manner in vitro. Finally, we show sustained replication of a fluorescent DIP in experimentally infected ferrets over a period of 14 days. Most importantly, DIPs were isolated from the lymphoid tissues which are a major site of CDV replication. Our established pipeline for detection, generation and assaying DIPs is transferable to highly pathogenic paramyxoviruses and will allow qualitative and quantitative assessment of the therapeutic effects of DIP administration on disease outcome. ImportanceDefective interfering (DI) genomes have long been considered inconvenient artifacts that suppressed viral replication in vitro. However, advances in sequencing technologies have led to DI genomes being identified in clinical samples, implicating them in disease progression and outcome. It has been suggested that DI genomes could be harnessed therapeutically. Negative strand RNA virus research has provided a rich pool of natural DI genomes over many years and they are probably the best understood in vitro. Here, we demonstrate identification, synthesis, production and experimental inoculation of novel CDV DI genomes in highly susceptible ferrets. These results provide important evidence that rationally designed and packaged DI genomes can survive the course of a wild-type virus infection.

microbiology↗

bioRxiv2021

Memory B cell repertoire for recognition of evolving SARS-CoV-2 spike

Memory B cell reserves can generate protective antibodies against repeated SARS-CoV-2 infections, but with an unknown reach from original infection to antigenically drifted variants. We charted memory B cell receptor-encoded monoclonal antibodies (mAbs) from 19 COVID-19 convalescent subjects against SARS-CoV-2 spike (S) and found 7 major mAb competition groups against epitopes recurrently targeted across individuals. Inclusion of published and newly determined structures of mAb-S complexes identified corresponding epitopic regions. Group assignment correlated with cross-CoV-reactivity breadth, neutralization potency, and convergent antibody signatures. mAbs that competed for binding the original S isolate bound differentially to S variants, suggesting the protective importance of otherwise-redundant recognition. The results furnish a global atlas of the S-specific memory B cell repertoire and illustrate properties conferring robustness against emerging SARS-CoV-2 variants.

immunology↗

bioRxiv2021

Deletion disrupts a conserved antibody epitope in a SARS-CoV-2 variant of concern

Multiple SARS-CoV-2 variants with altered antigenicity have emerged and spread internationally. In one lineage of global concern, we identify a transmitted variant with a deletion in its receptor binding domain (RBD) that disrupts an epitope which is conserved across sarbecoviruses. Overcoming antigenic variation by selectively focusing immune pressure on this conserved site may, ultimately, drive viral resistance.

microbiology↗

bioRxiv2021

Bifurcated monocyte states are predictive of mortality in severe COVID-19

Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection presents with varied clinical manifestations1, ranging from mild symptoms to acute respiratory distress syndrome (ARDS) with high mortality2,3. Despite extensive analyses, there remains an urgent need to delineate immune cell states that contribute to mortality in severe COVID-19. We performed high-dimensional cellular and molecular profiling of blood and respiratory samples from critically ill COVID-19 patients to define immune cell genomic states that are predictive of outcome in severe COVID-19 disease. Critically ill patients admitted to the intensive care unit (ICU) manifested increased frequencies of inflammatory monocytes and plasmablasts that were also associated with ARDS not due to COVID-19. Single-cell RNAseq (scRNAseq)-based deconvolution of genomic states of peripheral immune cells revealed distinct gene modules that were associated with COVID-19 outcome. Notably, monocytes exhibited bifurcated genomic states, with expression of a cytokine gene module exemplified by CCL4 (MIP-1{beta}) associated with survival and an interferon signaling module associated with death. These gene modules were correlated with higher levels of MIP-1{beta} and CXCL10 levels in plasma, respectively. Monocytes expressing genes reflective of these divergent modules were also detectable in endotracheal aspirates. Machine learning algorithms identified the distinctive monocyte modules as part of a multivariate peripheral immune system state that was predictive of COVID-19 mortality. Follow-up analysis of the monocyte modules on ICU day 5 was consistent with bifurcated states that correlated with distinct inflammatory cytokines. Our data suggests a pivotal role for monocytes and their specific inflammatory genomic states in contributing to mortality in life-threatening COVID-19 disease and may facilitate discovery of new diagnostics and therapeutics.

immunology↗

bioRxiv2020

Natural deletions in the SARS-CoV-2 spike glycoprotein drive antibody escape

Zoonotic pandemics, like that caused by SARS-CoV-2, can follow the spillover of animal viruses into highly susceptible human populations. Their descendants have adapted to the human host and evolved to evade immune pressure. Coronaviruses acquire substitutions more slowly than other RNA viruses, due to a proofreading polymerase. In the spike glycoprotein, we find recurrent deletions overcome this slow substitution rate. Deletion variants arise in diverse genetic and geographic backgrounds, transmit efficiently, and are present in novel lineages, including those of current global concern. They frequently occupy recurrent deletion regions (RDRs), which map to defined antibody epitopes. Deletions in RDRs confer resistance to neutralizing antibodies. By altering stretches of amino acids, deletions appear to accelerate SARS-CoV-2 antigenic evolution and may, more generally, drive adaptive evolution.

microbiology↗

bioRxiv2020

SARS-CoV-2 infection of African green monkeys results in mild respiratory disease discernible by PET/CT imaging and prolonged shedding of infectious virus from both respiratory and gastrointestinal tracts

Vaccines are urgently needed to combat the global coronavirus disease 2019 (COVID-19) pandemic, and testing of candidate vaccines in an appropriate non-human primate (NHP) model is a critical step in the process. Infection of African green monkeys (AGM) with a low passage human isolate of SARS-CoV-2 by aerosol or mucosal exposure resulted in mild clinical infection with a transient decrease in lung tidal volume. Imaging with human clinical-grade 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) co-registered with computed tomography (CT) revealed pulmonary lesions at 4 days post-infection (dpi) that resolved over time. Infectious virus was shed from both respiratory and gastrointestinal (GI) tracts in all animals in a biphasic manner, first between 2-7 dpi followed by a recrudescence at 14-21 dpi. Viral RNA (vRNA) was found throughout both respiratory and gastrointestinal systems at necropsy with higher levels of vRNA found within the GI tract tissues. All animals seroconverted simultaneously for IgM and IgG, which has also been documented in human COVID-19 cases. Young AGM represent an excellent species to study mild/subclinical COVID-19 disease and have shed light on unknown aspects of long-term virus shedding. They are ideally suited for preclinical evaluation of candidate vaccines and therapeutic interventions. One Sentence SummarySubclinical infection of African green monkeys infected with SARS-CoV-2 results in prolonged shedding of infectious virus from both respiratory and gastrointestinal tracts.

microbiology↗

bioRxiv2020

SARS-CoV-2 growth, furin-cleavage-site adaptation and neutralization using serum from acutely infected, hospitalized COVID-19 patients

SARS-CoV-2, the causative agent of COVID-19, emerged at the end of 2019 and by mid-June 2020, the virus has spread to at least 215 countries, caused more than 8,000,000 confirmed infections and over 450,000 deaths, and overwhelmed healthcare systems worldwide. Like SARS-CoV, which emerged in 2002 and caused a similar disease, SARS-CoV-2 is a betacoronavirus. Both viruses use human angiotensin-converting enzyme 2 (hACE2) as a receptor to enter cells. However, the SARS-CoV-2 spike (S) glycoprotein has a novel insertion that generates a putative furin cleavage signal and this has been postulated to expand the host range. Two low passage (P) strains of SARS-CoV-2 (Wash1: P4 and Munich: P1) were cultured twice in Vero-E6 cells and characterized virologically. Sanger and MinION sequencing demonstrated significant deletions in the furin cleavage signal of Wash1: P6 and minor variants in the Munich: P3 strain. Cleavage of the S glycoprotein in SARS-CoV-2-infected Vero-E6 cell lysates was inefficient even when an intact furin cleavage signal was present. Indirect immunofluorescence demonstrated the S glycoprotein reached the cell surface. Since the S protein is a major antigenic target for the development of neutralizing antibodies we investigated the development of neutralizing antibody titers in serial serum samples obtained from COVID-19 human patients. These were comparable regardless of the presence of an intact or deleted furin cleavage signal. These studies illustrate the need to characterize virus stocks meticulously prior to performing either in vitro or in vivo pathogenesis studies.

microbiology↗

bioRxiv2019

Measles skin rash: infection of lymphoid and myeloid cells in the dermis precedes viral dissemination to keratinocytes in the epidermis

Measles is characterised by fever and a maculopapular skin rash, which is associated with immune clearance of measles virus (MV)-infected cells. Histopathological analyses of skin biopsies from humans and non-human primates (NHPs) with measles rash have identified MV-infected keratinocytes and mononuclear cells in the epidermis, around hair follicles and near sebaceous glands. Here, we address the pathogenesis of measles skin rash by combining data from experimentally infected NHPs, ex vivo infection of human skin sheets and in vitro infection of primary human keratinocytes. Longitudinal analysis of the skin of experimentally MV-infected NHPs demonstrated that infection in the skin precedes onset of rash by several days. MV infection was initiated in lymphoid and myeloid cells in the dermis before dissemination to the epidermal keratinocytes. These data were in good concordance with ex vivo MV infections of human skin sheets, in which dermal cells were more targeted than the epidermal ones. To address viral dissemination to the epidermis and to determine whether the dissemination is receptor-dependent, we performed experimental infections of primary keratinocytes collected from healthy or nectin-4-deficient donors. These experiments demonstrated that MV infection of keratinocytes is nectin-4-dependent, and nectin-4 expression was higher in differentiated than in proliferating keratinocytes. Based on these data, we hypothesise that measles skin rash is initiated by migrating MV-infected lymphocytes that infect dermal skin-resident CD150+ immune cells. The infection is subsequently disseminated from the dermal papillae to nectin-4+ keratinocytes in the basal epidermis. Lateral spread of MV infection is observed in the superficial epidermis, most likely due to the higher level of nectin-4 expression on differentiated keratinocytes. Finally, MV-infected cells are cleared by infiltrating immune cells, causing hyperaemia and oedema, which give the appearance of morbilliform skin rash. Author SummarySeveral viral infections are associated with skin rash, including parvovirus B19, human herpesvirus type 6, dengue virus and rubella virus. However, the archetype virus infection that leads to skin rash is measles. Although all of these viral exanthemata often appear similar, their pathogenesis is different. In the case of measles, the appearance of skin rash is a sign that the immune system is clearing MV-infected cells from the skin. How the virus reaches the skin and is locally disseminated remains unknown. Here we combine observations and expertise from pathologists, dermatologists, virologists and immunologists to delineate the pathogenesis of measles skin rash. We show that MV infection of dermal myeloid and lymphoid cells precedes viral dissemination to the epidermal keratinocytes. We speculate that immune-mediated clearance of these infected cells results in hyperaemia and oedema, explaining the redness of the skin and the slightly elevated spots of the morbilliform rash.

microbiology↗