ETIDIOH - NEW

  ABSTRACT Vaccinia virus (VACV) confers cross-protective immunity against monkeypox virus (MPXV), the causative agent of mpox, and has therefore been extensively exploited as a preventive vaccine . VACV Tiantan strain (VTT) is a second-generation smallpox vaccine used in China in the last century, and there are consistent efforts to minimize its virulence and ensure its best safety for potential clinical applications. In this study, an attenuated VACV rVTT△C12K2△A45 was constructed by deletion of gene segments related to virulence genes , host range genes, immune regulatory genes, and other functional genes from the VTT genome by genetic engineering. Attenuation characteristics of rVTT△C12K2△A45 were confirmed by smaller plaque size, lower replication capacity in various mammalian cell lines along with tests for neurotoxicity in mice , and lesion formation on rabbit skin . Immunization in BALB/c mice with rVTT△C12K2△A45 induced both anti-MPXV and anti-VACV neutralizing antibodies ...

  Abstract The continuous evolution and global spread of highly pathogenic avian influenza (HPAI) H5N1 viruses , particularly clade 2.3.4.4b, pose major challenges for pandemic preparedness . This study evaluates a low-dose inactivated split-virus vaccine derived from H5N1 clade 2.3.4.4b, formulated with an Alum/CpG adjuvant , in a preclinical female mouse model . The vaccine induces strong humoral and cellular immunity , generating high titers of cross-reactive antibodies against diverse H5 hemagglutinin (HA) and across different N1 neuraminidase (NA) glycoproteins. The Alum/CpG adjuvant supports substantial antigen dose sparing and promotes a balanced Th1/Th2 profile. Functional assays show potent virus neutralization , neuraminidase inhibition , and antibody-dependent cellular cytotoxicity , alongside robust antigen-specific CD4+ and CD8+ T cell responses, efficient control of lung viral replication, and reduced lung inflammation . Vaccinated mice are fully protected from lethal...

  Abstract Ebola virus (EBOV) is the causative agent of Ebola disease (EBOD), a viral hemorrhagic fever with a notably high case fatality rate . Current treatments for EBOD are limited to monoclonal antibodies or two licensed viral vector vaccines , a recombinant vesicular stomatitis virus (rVSV)-vectored vaccine or an adenovirus and modified vaccinia Ankara regimen. However, comparisons of protection, efficacy, and durability with alternative nucleotide platforms remain understudied . Here, we evaluated the immunogenicity of an mRNA vaccine expressing the EBOV glycoprotein (GP) in parallel with rVSV- and DNA-based vaccine platforms . The mRNA EBOV-GP vaccine , formulated in lipid nanoparticles , elicited significantly higher levels of total IgG and neutralizing antibody titers compared to the rVSV-EBOV-GP vaccine. Linear antibody epitope analysis indicated a preference for targeting the mucin-like domain in EBOV-GP1 following rVSV-based vaccination, while the mRNA platform distinc...

  Abstract Influenza causes substantial morbidity and mortality worldwide. This randomized, open-label, phase 1 trial (ClinicalTrials.gov, NCT05397223, date of registration: May 31, 2022) compared the immunogenicity of an mRNA-based quadrivalent influenza hemagglutinin (HA) vaccine (mRNA-1010) with a licensed comparator (FLUAD) in adults aged 18-75 years . We evaluated humoral and cellular immune responses using hemagglutination inhibition assays , flow cytometry-based memory B cell (MBC) profiling, and intracellular cytokine staining for T-cell characterization. Both vaccines elicited durable hemagglutination inhibition titers and increased HA-specific MBC responses across four vaccine strains. Compared with FLUAD, mRNA-1010 induced higher frequencies of classical and activated MBCs specific to the H3 HA included in the vaccine, while inducing similar MBC responses to the other strains. mRNA-1010 and FLUAD generated strong HA-specific CD4+ T-cell responses; a trend toward higher C...

  ABSTRACT Oropouche virus (OROV) is reemerging in the Americas, along with a growing threat to global public health . Recent outbreaks have witnessed the first reported fatalities , vertical transmissions , and intercontinental importations of OROV, underscoring its expanding risk . Despite this, no vaccines or specific therapeutics are available, and fundamental research on OROV vaccinology and antigenicity remains limited. Here, we show that co-expression of the M polyprotein and nucleocapsid protein (NP) drives the assembly of OROV virus-like particles (VLPs) with high immunogenicity . Using the prototype strain OROV/sloth/Brazil/PA-UG-BeAn19991/1960, we developed an mRNA vaccine, M/N-vac, encoding these VLPs . Immunization with M/N-vac in mice elicited robust OROV-specific IgG and pseudovirus-neutralizing antibodies that cross-reacted with a contemporary circulating strain, hOROV/Brazil/AM-UKY-AM0088/2024. The vaccine also induced a durable, antigen-specific Th1-biased cellula...

  Abstract Seasonal and pandemic influenza viruses are continuous threats to human health, requiring rapid development of vaccines to multiple evolving viral strains. RNA vaccine technologies have the adaptability and manufacturability to facilitate pandemic preparedness but have limited flexibility in their route of administration , reducing the ability to establish local protective immune responses such as respiratory mucosal immunity . Here, we describe monovalent and bivalent replicon vaccines against A/Vietnam/1203/2004 H5N1 and A/Anhui/PA-1/2013 H7N9. These replicon vaccines express either H5 or H7 hemagglutinin and are formulated with a nanostructured lipid carrier (NLC) that permits both intramuscular (IM) and intranasal (IN) dosing. In mice , IM vaccination established systemic humoral and cellular responses but no detectable mucosal response , while IN administration induced robust systemic and mucosal immunity . The replicon-NLC vaccines protected against morbidity and m...

  ABSTRACT Monoclonal antibodies represent potent biological countermeasures against a wide range of human diseases ; however, their clinical application and widespread use are limited by the high cost and complexity of antibody production and manufacturing. The mRNA-lipid nanoparticle (mRNA-LNP) platform offers a versatile strategy for vaccine development and protein-replacement therapies. Since the COVID-19 pandemic, a number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)- neutralizing antibodies have been identified, with several granted emergency use authorization for patients. Here, we report the design and generation of mRNA-LNPs encoding two SARS-CoV-2-neutralizing antibodies , 76E1 and LY1404, which, respectively, target the spike protein’s fusion peptide (FP) and receptor-binding domain (RBD). We demonstrated that a single intramuscular administration of these mRNA-LNPs in mice resulted in robust antibody production that sustained in circulation for 7–14 d...

  Abstract The highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 represent a major threat to animal and public health . The current panzootic with H5 clade 2.3.4.4b has caused numerous, widespread outbreaks in various domestic and wild avian species with high mortalities, massive losses and a high frequency of spillover events to unexpected novel mammalian hosts such as dairy cows . The global H5N1 situation raises serious concerns about zoonotic risks due to effective mammal-to-mammal transmission . Therefore, it is critical to increase surveillance intensity of a broadened species range, particularly at the human-animal interface . For this purpose, reliable and cost-effective serological tools that are easy to perform and suitable for high-throughput screenings are critically needed. The newly developed double antigen ELISA format employing a luminescence-based detection technology has demonstrated to comply with such prerequisites. The assay allowed the detectio...

ABSTRACT Faced with the global monkeypox outbreak, current vaccine development predominantly focuses on the mRNA platform despite its limitations in stability and long-term efficacy. Here, we engineered a recombinant vesicular stomatitis virus (rVSV)-vectored cocktail vaccine encoding four conserved monkeypox virus (MPXV) antigens (A35R, A29L, M1R, and B6R; >94% clade homology), leveraging the thermostable properties of the VSV platform validated for 4°C storage in Ebola vaccines. In BALB/c mice , this multi-antigen vaccine elicited a rapid humoral response with specific IgG detectable by day 7, effectively neutralized the virus, and induced a robust Th1/Th2 balanced cytokine response . Immunization conferred 100% survival against lethal vaccinia virus WR strain challenge , with undetectable viral loads in the lungs and serum , and sustained efficacy against secondary infection at 60 days. Histopathology confirmed minimal lung damage in vaccinated mice . Crucially, upon the successi...

  Significance Zika virus causes microcephaly in fetuses and no vaccines or therapeutics currently exist against it . Mature and immature flavivirus particles are infectious. Here, we showed the cryoelectron microscopy (cryoEM) structures of an ultrapotent A9E human antibody , complexed with both mature (mZIKV) and immature (immZIKV) Zika virus, and the antibody neutralization mechanism . One important characteristic is that Fab A9E can distort both mZIKV and ImmZIKV particle structures. Additionally, Fab A9E or IgG A9E LALA mutant can abolish or reduce the overall infection to myeloid cells when added to other infection enhancing antibody DV62.5:immZIKV complexes. Thus, antibody A9E represents a promising potential prophylactic and therapeutic candidate , as it is effective against all maturation states of Zika virus. Abstract Zika virus (ZIKV), a flavivirus, causes a range of clinical complications including microcephaly in human fetuses . Currently, there is no treatment or vacc...

  Abstract Human (avian) influenza A viruses, especially highly pathogenic avian influenza (HPAI) viruses, pose a significant public health threat , and a multivalent vaccine is the primary prophylactic measure to control these viruses. To establish such a vaccine, we generated two multivalent vesicular stomatitis virus (VSV)-based vaccine candidates (V-EtM2e/H505 and V-EtM2e/H522) and characterized their ability to induce protective immune responses. Our results revealed that vaccine immunization in mice induced high humoral immune responses against both the HPAI hemagglutinin (HA) protein and the ectodomain of M2 (M2e) protein . Intriguingly, vaccine-immunized mouse sera exhibited highly efficient neutralizing activity against the corresponding H5 pseudovirus and mediated potent and broad antibody-dependent cellular cytotoxicity (ADCC) activity against M2e derived from human and avian influenza H5, H1, H3, and H7 viruses . Furthermore, both intranasal and intramuscular immunizati...

  Highlights •  We generated a recombinant reporter OROV that expresses the eGFP fluorescent protein in infected cells. •  We found that remdesivir efficiently inhibited the replication of Oropouche virus (OROV) using this reporter OROV. •  We demonstrated strain-dependent differences in the replication efficiency of OROV. Abstract The Oropouche virus (OROV), an orthobunyavirus transmitted by biting midges, is the causative agent of Oropouche fever , which has caused multiple outbreaks in South and Central America . During the most recent epidemic in 2023–2025, more than 25,000 laboratory-confirmed cases were reported in Brazil , and no licensed antivirals have been reported to be effective date. In this study, we generated a recombinant OROV-expressing enhanced green fluorescent protein (rOROV/GFP) to facilitate rapid and sensitive antiviral evaluation . Growth kinetics demonstrated that rOROV/GFP replicated less efficiently than wild-type rOROV and that the histori...

  Abstract Nipah virus (NiV) is a zoonotic pathogen that causes severe encephalitis and respiratory disease in humans and multiple mammalian species. However, no licensed vaccines or therapeutics are currently available against NiV infection. In this study, we developed three mRNA vaccine candidates using a lipid nanoparticle (LNP) delivery platform : mRNA-F-LNP, comprising mRNA encoding the fusion protein (F); mRNA-G-LNP, containing mRNA encoding the attachment glycoprotein (G); and mRNA-GF-LNP, in which mRNAs encoding both F and G proteins were co-encapsulated at a 1:1 molar ratio. All three mRNA-LNPs induced robust and sustained immune responses in both mice and Syrian hamsters . Sera from immunized Syrian hamster showed high levels of cross-neutralizing antibodies against both NiV-Malaysia (NiV-M) and NiV-Bangladesh (NiV-B) strains. Notably, all three mRNA-LNPs conferred complete protection against a lethal challenge with NiV-M in Syrian hamsters. These findings demonstrate tha...

  Abstract The highly pathogenic avian influenza H5N1 virus clade 2.3.4.4b has been spreading globally since 2022 , causing mortality and morbidity in domestic and wild birds, as well as in mammals , which underscores its potential to cause a pandemic . Here, we generate a panel of anti-hemagglutinin (HA) human monoclonal antibodies (mAbs) against the H5 protein of clade 2.3.4.4b. To develop human chimeric antibodies , H2L2 Harbor Mice®, which express human immunoglobulin germline genes, were immunized with H5 and N1 recombinant proteins from A/mallard/New York/22-008760-007- original/2022 H5N1 virus. Through hybridoma technology, sixteen fully human mAbs are generated, most of which show cross-reactivity against H5 proteins from different clade 2.3.4.4 virus variants . Fourteen out of the sixteen mAbs neutralize the virus in vitro . The mAbs with the strongest hemagglutination inhibition activity also demonstrate greater neutralizing capacity and show increased protective effects ...

  Abstract Influenza remains a significant global public health concern. Live-attenuated influenza vaccines (LAIVs) are recognized as effective interventions for influenza prevention. Currently, two types of LAIVs are licensed for human use: one developed through cold-adapted viral gene mutation and the other through the deletion of the viral NS1 gene . However, the similarities and differences in these two LAIVs’ efficacy, safety, and immune responses have not been thoroughly studied. This study constructed a gene-deficient live-attenuated vaccine strain, CA4-dNS1, and a gene locus-mutated attenuated vaccine strain, CA4-cold , to compare their in vivo and in vitro replication capacity , broad-spectrum protective efficacy , safety, and immunogenicity . The results showed that both LAIVs provide comparable broad-spectrum protection against lethal H1N1 and H5N1 influenza challenges in mice and induce similar humoral and mucosal immune responses . Notably, the CA4-cold vaccine strain ...

  Abstract The global spread of highly pathogenic avian influenza A(H5N1) viruses poses a serious pandemic threat . While sustained human-to-human transmission has not occurred, widespread circulation in birds , increased detection in mammals , and occasional human spillovers underscore the need for safe and effective vaccines . We evaluated an H5 mRNA vaccine candidate in ferrets using recent clade 2.3.4.4b A(H5N1) human isolates. Vaccination elicited strong neutralizing antibodies , conferred robust protection against lethal challenge , and significantly reduced viral titers . In a direct contact transmission model , mRNA vaccination decreased virus shedding in inoculated ferrets and reduced onward transmission ; it also protected vaccinated contact ferrets from infection following exposure to virus-shedding, unvaccinated ferrets. Additionally, sera from vaccinated animals cross-neutralized clade 2.3.2.1e human viruses to varying degrees, depending on the strain. These findings d...

  ABSTRACT Passive administration of broadly neutralizing anti-influenza monoclonal antibodies (mAbs) before or after virus infection can prevent or alleviate disease. Unlike seasonal influenza, infection with zoonotic avian influenza viruses can lead to acute respiratory distress syndrome and high mortality in humans. Respiratory tract-targeting antibody delivery appears to be more clinically relevant and effective for zoonotic influenza treatment. In this study, the efficacy of an anti-H7N9 murine mAb 4B7 and its humanized form (chi4B7) against H7 subtype influenza viruses administered through the intranasal route was investigated in mice . 4B7 recognizes critical residues in the vestigial esterase domain and receptor-binding sites in the hemagglutinin of H7N9 virus . The antibody had cross-H7 binding, hemagglutination inhibition, and neutralizing activities. In particular, the dose of 4B7 required for prophylactic protection against H7N9 infection was significantly reduced in mi...

  Significance The high-resolution cryo-EM structure indicates that the human antibody 6Y13 binds strongly to a conserved pan-H7 epitope on the hemagglutinin head , distinct from the receptor-binding site and lateral patch. However, 6Y13 can broadly neutralize H7 viruses , fully protect H7N9 -infected mice, and potently block receptor binding through mechanisms, independent of Fc-mediated steric hindrance. Abstract Zoonotic H7N9 avian influenza virus infection remains a global concern because of its pandemic potential . Therefore, developing effective antibodies and vaccines against H7N9 is vital for preventing and controlling major outbreaks . Here, we isolated a human VH3-30 gene-encoded antibody , designated 6Y13 , from a survivor of H7N9 infection . This antibody recognized the hemagglutinins (HAs) of the representative H7 subtype zoonotic viruses spanning two decades of antigenic evolution and potently neutralized epidemic H7N9 viruses in vitro. Moreover, 6Y13 conferred comple...

  Abstract Mucosal influenza vaccines may provide improved protection against infection and transmission , but their development is hindered by absence of immune correlates of protection . Here, we report a randomized, controlled phase I trial of a recombinant influenza A/H5 (A/Indonesia/05/2005, clade 2.1) hemagglutinin vaccine formulated with a nanoemulsion adjuvant (W805EC). The vaccine is administered intranasally in two doses 28 days apart at three antigen levels. Controls receive unadjuvanted H5 or placebo. Six months later, participants receive an intramuscular boost with unadjuvanted inactivated A/H5N1 (A/Vietnam/1203/2004, clade 1) vaccine. Primary outcomes are solicited and unsolicited adverse events (AEs), laboratory safety abnormalities, medically-attended AEs, potential immune-mediated conditions, new-onset chronic conditions, and serious AEs. All vaccines are well tolerated. After the intranasal series, hemagglutination inhibition and microneutralization responses are...

  Abstract Background No vaccine is currently available for Lassa fever, a viral hemorrhagic disease that is estimated to cause thousands of deaths each year in western Africa . A replication-competent recombinant vesicular stomatitis virus–vectored vaccine encoding a Lassa virus (LASV) glycoprotein complex, rVSVΔG-LASV-GPC, has been developed, but data on its safety and immunogenicity are limited. Methods In this phase 1, double-blind trial conducted in the United States and Liberia, we randomly assigned healthy adults (18 to 50 years of age) to receive rVSVΔG-LASV-GPC or placebo intramuscularly . Participants received a single vaccine dose of 2×104 plaque-forming units (PFU), 2×105 PFU, 2×106 PFU, or 2×107 PFU or placebo or received two vaccine doses of 2×107 PFU or placebo, within a window of 6 to 20 weeks. The side-effect profile was assessed according to the incidence of solicited and unsolicited adverse events (primary end point). Because Lassa fever can cause sensorineural h...