ETIDIOH - NEW

  Abstract Mpox poses a heightened risk of severe disease and mortality among individuals with HIV , yet the molecular mechanisms and immunopathology underlying multi-organ damage caused by the mpox virus (MPXV), particularly in the context of HIV co-infection, remain poorly understood. Here, we observe increased MPXV replication, more extensive skin lesions, and impaired humoral and cellular immune responses in SIV-MPXV co-infected rhesus macaques compared to those infected with MPXV alone. Multi-organ proteomic and phosphoproteomic analyses reveals upregulation of proteins involved in immune and inflammatory pathways in skin lesions and across multiple organs, especially in immune-related tissues. Abnormal activation of DNA replication and cell cycle signaling pathways , which may contribute to enhanced viral replication, is evident in both MPXV and SIV-MPXV co-infected groups. CDK4/6 may present a potential therapeutic target to suppress MPXV replication. These comprehensive pro...

Abstract The continuous evolution and widespread dissemination of highly pathogenic avian influenza (HPAI) H5N1 viruses , particularly clade 2.3.4.4b, pose critical challenges to global pandemic preparedness . In this study, we assessed a low-dose inactivated split virus vaccine derived from clade 2.3.4.4b H5N1, formulated with an Alum/CpG adjuvant , using a preclinical mouse model . This vaccine induced potent humoral and cellular immune responses , generating high titers of cross-reactive antibodies targeting both hemagglutinin (HA) and neuraminidase (NA) glycoproteins across homologous and heterologous H5 clades. The Alum/CpG adjuvant enabled significant antigen dose-sparing while promoting a balanced Th1/Th2 immune profile . Functional analyses demonstrated strong virus neutralization , neuraminidase inhibition, and potent antibody-dependent cellular cytotoxicity activity . Additionally, the vaccine elicited robust antigen-specific CD4+ and CD8+ T cell responses and effectively con...

Significance An intranasal vaccine offers many unique advantages over traditional intramuscular-delivered vaccines . Here, we developed SARS-CoV-2 Omicron XBB.1.5 spike-based monovalent and trivalent vaccines using the live attenuated measles virus (MeV) and mumps viruses (MuV) as vectors . Intranasal immunization of hamsters and mice with monovalent and trivalent vaccines induces robust and broadly neutralizing antibodies , mucosal IgA antibodies , and lung-resident memory T cells , providing complete protection of the lung and nasal turbinate against challenges with SARS-CoV-2 WA1 and Omicron subvariants XBB.1.5, EG.5, and JN.1 . In addition, intranasal immunization efficiently blocks transmission of SARS-CoV-2 WA1 and Omicron XBB.1.5 among the hamsters by direct contact. Therefore, MeV- and MuV-based intranasal vaccines are highly promising next-generation COVID-19 vaccine candidates that can prevent virus infection and transmission. Abstract The emergence of immune-evasive SARS-CoV...

  Abstract In an effort to avert future pandemics, surveillance studies aimed at identifying zoonotic viruses at high risk of spilling over into humans act to monitor the "viral chatter" at the animal-human interface. These studies are hampered, however, by the diversity of zoonotic viruses and the limited tools available to assess pandemic risk. Methods currently in use include the characterization of candidate viruses using in vitro laboratory assays and experimental transmission studies in animal models. However, transmission experiments yield relatively low-resolution outputs that are not immediately translatable to projections of viral dynamics at the level of a host population. To address this gap, we present an analytical framework to extend the use of measurements from experimental transmission studies to generate more quantitative risk assessments. Specifically, we use within-host viral titer data from index and contact animals to estimate parameters relevant to tran...

Abstract Monkeypox virus (MPXV) has re-emerged globally since May 2022, posing a significant public health threat . To address this, we develop two multivalent mRNA vaccine candidates —AAL, encoding three MPXV antigens, and AALI, which combines AAL with an immune-enhancing IFN-α protein. Both vaccines are delivered via mannose-modified lipid nanoparticles to target dendritic cells . Here we show that these vaccines elicit strong antibody responses against vaccinia virus and multiple MPXV clades , induce robust memory B-cell and T-cell responses, and promote dendritic cell maturation . In mouse challenge models , both vaccines provide protection against clade IIb MPXV and vaccinia virus , significantly reducing viral loads and preventing lung damage. Immune profiling reveals enhanced B- and T-cell receptor diversity and distinct CDR3 motifs post-vaccination. These findings demonstrate the potential of using mRNA-based multivalent vaccines as an effective strategy for preventing mpox and...

  ABSTRACT The H5N1 strain of influenza A virus (IAV) continues to cause severe infections in a range of avian and mammalian species , including sporadic but concerning cases in humans. There is growing concern that circulating H5N1 strains could lead to widespread human outbreaks . Research with highly pathogenic H5N1 viruses is restricted to Biosafety Level 3 (BSL-3) laboratories. Vesicular stomatitis virus (VSV)-based vaccine vectors expressing heterologous viral proteins from Ebola, SARS-CoV-2, Lassa virus, etc., have previously been shown to be safe and effective in animal models and human clinical trials . Here, we report the development of a recombinant VSV expressing the hemagglutinin (HA) and neuraminidase (NA) genes of H5N1 IAV (H5N1-VSV), which serves as a versatile platform to study various aspects of H5N1 IAV biology. H5N1-VSV replicated robustly to titers comparable to those of the full H5N1 virus in multiple cell lines. In mice , H5N1-VSV vaccination was safe, elicit...

  ABSTRACT Airborne transmissibility of avian influenza viruses (AIVs) in humans is considered an essential component of their pandemic risk . Although several viral factors regulating airborne transmission (AT) have been delineated, it is not known what, if any, responses at the respiratory epithelia are determinants of AIV AT. Using responses in the ferret nasal epithelium to a panel of H1N1 AIVs, we describe host responses that segregate with AT phenotypes . AIV infection upregulated interferon alpha and gamma responses and IL-6 JAK-STAT signaling and downregulated oxidative phosphorylation . Single-cell transcriptomics revealed that cellular genotoxic stress and NF-kB, interferon, and cell fate pathways differentiated host responses to AIVs with different transmissibilities. These responses culminated in greater AIV antigen-containing exudate and debris in the respiratory spaces of the nasal epithelium of ferrets inoculated with AT AIVs. More abundant CMPK2, SP100, and CXCL10 t...

Abstract Influenza A virus (IAV) poses a significant global health risk, with highly pathogenic strains like H5N1 (CFR ~52%) causing severe disease compared to less lethal but more transmissible strains like H1N1 (CFR 0.01-0.03%). Although IAV primarily infects lung epithelial cells , causing cell death and tissue damage , the molecular basis of strain-specific pathogenesis remains poorly understood. Here we show that in cell culture , H5N1 induced more rapid and extensive cell death than H1N1. Since Interferon (IFN) signaling is key to innate immunity, we examined its role in virus-induced cell death using STAT1-knockout A549 cells and JAK/STAT pathway inhibitors like Baricitinib . Both approaches reduced cell death across various IAV strains, including H1N1, H5N1, H7N9 , and H3N2 . However, inhibition increased viral titers , raising concerns about its clinical use in isolation. To overcome this, we tested a combination of Oseltamivir (antiviral) and Baricitinib (anti-inflammatory). ...

Highlights •  Mol shows greater antiviral effects against IAV and IBV in cell cultures. •  Mol and Ose together showed a synergistic effect against IAV. •  In mice, Mol alone or with Ose reduced lung injury and viral load. Abstract Oseltamivir, a neuraminidase inhibitor, is widely used in the clinic for treating influenza virus infections . However, suboptimal efficacy and risk of drug resistance development remain major challenges. Molnupiravir , a ribonucleoside analog, was originally developed to treat influenza, but was repurposed and first approved for treating COVID-19 in 2021. Considering their complementary mode-of-actions, this study aimed to investigate the combinatorial activities of oseltamivir and molnupiravir against influenza virus infections . In cell culture models, we found that β-d-N4-hydroxycytidine (NHC), the active form of molnupiravir, exerted more potent antiviral activities against influenza A and B viruses , when compared to oseltamivir treatment...

Abstract Outbreaks of H5 highly pathogenic avian influenza A viruses (HPAIVs) in animals pose a threat to humans immunologically naïve to avian influenza viruses. However, annual vaccination, such as for seasonal influenza is not planned because the number of human patients infected with H5 HPAIVs is small, and the possibility of human-to-human transmission of H5 HPAIVs is low at present. However, various clades of H5 HPAIVs have emerged continuously . Therefore, a vaccine that confers long-term and cross-clade immunity is required. To examine the long-term effectiveness and cross-clade reactivity of an H5 influenza virus vaccine, cynomolgus macaques were infected with an H5N1 HPAIV 5 years after two subcutaneous vaccinations with inactivated H5N1 whole-virus particles (H5 clade classical/outlier), which showed higher immunogenicity than did split vaccines in our previous studies. Neutralization titers against the vaccine strain were maintained for 5 years , and a recall immune respons...

Editor’s summary The vast majority of the human population has immunity to influenza A virus (IAV) by prior infection, vaccination, or both . However, protection is generally subtype-specific , and it is not clear whether prior infection against one subtype could confer protection against clade 2.3.4.4b H5N1 IAVs , which are currently circulating in birds and dairy cows . Here, Restori et al. demonstrated that prior infection with the 2009 pandemic H1N1 IAV was protective against subsequent direct infection with H5N1 IAV in ferrets. Moreover, prior immunity reduced susceptibility to infection by transmission from an infected donor ferret. These data suggest that prior immunity to IAV, especially to the 2009 pandemic H1N1 virus, may offer a degree of protection against H5N1 infection. —Courtney Malo Abstract Zoonotic infections with emerging influenza viruses occur in the context of population-wide immunity to seasonal strains . Because of the worldwide spread of highly pathogenic clade...

Abstract Sudan virus (SUDV) causes highly lethal outbreaks of hemorrhagic disease throughout Africa , but there has yet to be an approved vaccine or therapeutic to combat this public health threat. The most common route of natural exposure to filoviruses is through mucosal contact which greatly impacts initial viral replication. Historically, SUDV animal models used an intramuscular infection route . Here, we sought to further characterize an animal model using mucosal challenge routes and compared the impact that intramuscular, intranasal, or aerosol exposure had on SUDV pathogenicity in a ferret model . We determined that the route of infection did not significantly impact overall SUDV pathogenicity; only subtle changes were detected in magnitude of viremia and oral viral shedding. Additionally, we sought to determine if preexisting Lloviu virus (LLOV) immunity could protect ferrets from lethal SUDV infection. We found that the previous immunity elicited by LLOV infection was not suf...

Abstract In March 2024, clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses were first detected in U.S. dairy cattle . Similar viruses have since caused 70 zoonotic human infections . To assess changes to zoonotic potential , we characterized A( H5N1 ) clade 2.3.4.4b viruses isolated from cows’ milk and birds . Bovine-derived viruses are lethal in mice and ferrets and transmit to direct but not airborne contact ferrets. All viruses replicate in human bronchial epithelial cells despite preferentially binding avian virus-like receptors. The bovine-derived viruses remain susceptible to FDA-approved antivirals , and they are inhibited by sera from ferrets vaccinated with WHO-recommended candidate vaccine viruses (CVV) or human sera from clade 2.3.4.4c vaccinees. While 2.3.4.4b viruses induce severe disease in mammalian models , they retain many avian virus-like characteristics. Combined, we conclude that the risk of contemporary bovine-derived viruses to humans not in contact ...

Abstract With the recent rise in cases of highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b infection in humans and animals , there is an associated increase in the risk of human-to-human transmission . In this study, we characterize a recombinant A(H5N1) A/American Wigeon/South Carolina/22/000345-001/2021 (A/AW/SC/2021) clade 2.3.4.4b vaccine . Purified recombinant A/AW/SC/2021 HA trimers formulated with Matrix-M® adjuvant, saponin-cholesterol-phospholipid combination arranged in cage-like particles, are found to non-covalently anchor to the vertices of the Matrix-M and form A(H5N1) HA–Matrix-M nanoparticles (H5-MNPs). In naïve female mice , two intranasal (IN) or intramuscular (IM) doses of A/AW/SC/2021 H5-MNP vaccine induces robust antibody- and cell-mediated immune responses , including neutralizing antibodies against A(H5N1). In non-human primates (NHPs) primed with seasonal influenza vaccine , a single IM or IN dose of the A/AW/SC/2021 H5-MNP vaccine induces geometr...

ABSTRACT Effective vaccines are an important public health tool which may be needed to combat the emerging, highly pathogenic H5N1 avian influenza viruses currently circulating in cattle and poultry in the United States . While nucleic acid-based vaccines such as mRNA -lipid nanoparticles (LNPs) have several potential advantages during a viral epidemic compared to traditional seasonal influenza vaccines , their utility and efficacy against H5N1 viruses remain incompletely defined. Here, we developed novel DNA- and mRNA-LNP-based vaccines encoding both hemagglutinin (HA) and neuraminidase (NA) proteins from the human-isolated highly pathogenic avian influenza H5N1 strain, A/Texas/37/2024, in a single open reading frame. This dual-antigen expression approach elicited strong protective immune responses targeting both the HA and NA proteins and provided complete protection against lethal viral challenges in a murine model . The pre-clinical data described in this work suggest that these mu...

Abstract Avian Influenza viruses (AIVs) present a public health risk, especially with seasonal vaccines offering limited protection. AIV H5N1 clade 2.3.4.4b has caused a multi-state outbreaks in the United States (US) poultry and cattle since March 2024, raising pandemic concerns . We developed a nonstructural protein 1 (NS1)-deficient mutant of a low pathogenic version of the cattle-origin human influenza A/Texas/37/2024 H5N1 , namely LPhTXdNS1, and assessed its safety, immunogenicity, and protection efficacy . LPhTXdNS1 is attenuated in vitro , showing reduced replication efficiency in Vero cells and inability to control IFNβ promoter activation. The LPhTXdNS1-immunized C57BL/6 J mice exhibit significantly reduced viral replication and pathogenicity compared to those infected with the low pathogenic version expressing NS1, namely LPhTX. Notably, a single intranasal dose of LPhTXdNS1 elicited protective immune responses, providing robust protection against lethal wild-type H5N1 challe...

Summary Background Clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) (HPAI H5N1) viruses have spread prolifically in dairy cattle in the US , resulting in dozens of human infections , some without well-established links to animal contacts. Many wild mammals have also been affected, including peridomestic house mice. Methods Here, we evaluated susceptibility, tissue tropism, and shedding in female PWK/PhJ and BALB/cJ mice , two laboratory strains derived from house mice that differ in expression of the antiviral restriction factor Mx1. PWK/PhJ mice, which were selected for their natural expression of Mx1, better reflect the antiviral capacity of most wild house mice, whereas BALB/cJ mice lack functional Mx1. Findings We found that, regardless of Mx1 expression status, mice are susceptible to infection by dairy cattle HPAI H5N1 viruses , that infection leads to systemic spread to non-respiratory sites, and that infected animals shed virus into the environment via urine. Shed virus...

ABSTRACT Recently, human infections with H10 influenza viruses, including H10N8 and H10N3, have been reported. In January 2024 , a case of H10N5 and H3N2 co-infection was reported in Zhejiang Province, China , which is the first human infection with H10N5 avian influenza virus (AIV) globally. Almost simultaneously, we isolated a wild bird-derived H10N5 strain similar to the human H10N5 strain. To assess the public health risk , it is necessary to understand the zoonotic characteristics of these novel H10N5 viruses. Here, we evaluated the biological characteristics of human H10N5 , wild bird H10N5, as well as poultry H10N8 in vitro and in vivo. We demonstrate that the novel H10N5 isolates infected and replicated effectively in human lung epithelial cells . They infected BALB/c mice without adaptation , which exhibited robust pathogenicity and caused mouse death. In guinea pig transmission experiments , the H10N5 strain spread through neither direct contact nor airborne exposure , wherea...

Abstract Collection of systemic tissues from influenza A virus (IAV)-infected ferrets at a fixed timepoint post-inoculation represents a frequent component of risk assessment activities to assess the capacity of IAV to replicate systemically. However, few studies have evaluated how the frequency and magnitude of IAV replication at discrete tissues contribute to within-host phenotypic outcomes, limiting our ability to fully contextualize results from scheduled necropsy into risk assessment settings. Employing aggregated data from ferrets inoculated with > 100 unique IAV ( both human- and avian-origin viruses, spanning H1, H2, H3, H5, H7, and H9 subtypes ), we examined relationships between infectious virus detection in four discrete tissue types ( nasal turbinate, lung, brain, and olfactory bulb [BnOB]) to clinical outcomes of IAV-inoculated ferrets, and the utility of including these discrete tissue data as features in machine learning (ML) models. We found that addition of viral ti...

Abstract Panzootic spillover of H5N1 virus clade 2.3.4.4b has resulted in expanded host range among placental mammals , with lactation transmission via milk documented. Whether infection during pregnancy leads to in utero or lactational vertical transmission remains unknown. Pregnant outbred mice were infected with A/bovine/Ohio/B24OSU-472/2024 during the second or third trimester equivalent. Second trimester infection caused in utero infection , with infectious virus detected in the uterus, placenta, and fetus . Birth following third trimester infection resulted in offspring with decreased size and neurodevelopmental delays , with infectious virus detected in the neonatal milk ring and lungs as well as mammary tissues . Ongoing H5N1 infections present increased risk for human exposure and an H5N1 vertical transmission model in placental mammals is essential for understanding viral spread and evaluating treatments during pregnancy. Source: BioRxIV,  https://www.biorxiv.org/content/...