ETIDIOH - NEW

  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...

  Abstract Maintaining tissue function while eliminating infected cells is fundamental, and inflammatory damage plays a major contribution to lethality after lung infection . We tested 50 immunomodulatory regimes to determine their ability to protect mice from lethal infection . Only neutrophil depletion soon after infection prevented death from influenza. This result suggests that the infected host passed an early tipping point after which limiting innate damage alone could not rescue lung function. We investigated treatments that could have efficacy when administered later in infection. We found that partial limitation of viral spread together with enhancement of epithelial repair, by interferon blockade or limiting CD8+ T cell–mediated killing of epithelial cells , reduced lethality . This finding highlights the importance of rebalancing repair and damage processes in the survival of pulmonary infections. Source:  Link:  https://www.science.org/doi/10.1126/science.adr4...

  Abstract The Middle East respiratory syndrome coronavirus (MERS-CoV) remains a highly significant threat to global public health . Dromedary camels are the zoonotic source of human infection. All cases of zoonotic Middle East respiratory syndrome (MERS) have occurred in Middle Eastern countries despite MERS-CoV infection of camels being widespread in Africa . This disparity in the geographic burden of the disease may be due to genomic differences between MERS-CoV circulating in Middle Eastern countries (clades A and B) versus those infecting camels in Africa ( clade C ), although the precise genetic determinants of virulence remain to be elucidated. The objective of the studies reported here was to evaluate differences in the magnitude of virus shedding and in transmissibility of clades A/B and C viruses using alpacas as a surrogate for dromedary camels. We found that two of three African-origin, clade C strains of MERS-CoV induced very reduced levels of virus shedding and were t...

  ABSTRACT Swine acute diarrhea syndrome coronavirus (SADS-CoV) is a bat-originated virus causing severe diseases in piglets . Since the 2016 outbreak , diverse SADS-related CoVs (SADSr-CoVs) have been detected in Rhinolophus bats in China and Southeast Asia , but their potential interspecies infection and pathogenicity remain unknown. Herein, we sequenced the spike (S) genes of bat SADSr-CoVs and classified them into four genotypes . We constructed an infectious SADS-CoV cDNA clone (rSADS-CoV) and nine recombinant viruses by replacing the SADS-CoV S gene with that of bat SADSr-CoVs. Recombinant SADSr-CoVs could replicate efficiently in respiratory and intestinal cell lines and human- and swine-derived organoids and caused varying tissue damage and mortality in suckling mice. These viruses can be classified into at least five serotypes based on cross-neutralization assays . Our findings highlight the potential risk of interspecies infection and provide important information for fut...

  ABSTRACT With the SARS-CoV-2 Omicron XBB.1.9 subvariants circulating worldwide, two XBB.1.9 variants, EG.5.1 and HK.3 , spread rapidly and became dominant in mid-2023. However, the spike features, pathogenicity, and transmissibility of HK.3 are largely unknown. Here, we performed multiscale investigations to reveal the virological features of XBB.1.9 subvariants , including the newly emerging HK.3 . HK.3 revealed high replication efficiency and enhanced TMPRSS2 utilization in vitro. The HK.3 spike exhibited enhanced processing, although its infectivity, fusogenicity, and human ACE2 (hACE2) binding affinity were comparable to those of the EG.5 and XBB.1 spikes. All XBB.1.9.1, EG.5.1, and HK.3 strains demonstrated efficient transmission in hamsters , although XBB.1.9.1 exhibited stronger fitness in the upper airways . XBB.1.9.1, EG.5.1, and HK.3 exhibited greater pathogenicity than BA.2 in H11-K18-hACE2 hamsters. Our studies provide insights into the newly emerging pathogens EG.5.1...

  Abstract Influenza viruses cause hundreds of thousands of infections globally every year. In the past century, seasonal influenza viruses have included H1N1, H2N2 or H3N2 strains . H2N2 influenza viruses circulated in the human population between 1957-1968 . Previously, our group demonstrated a lack of H2N2 influenza virus immunity in individuals born after 1968 , as well as the effectiveness of hemagglutinin (HA) based vaccines for multiple influenza virus subtypes. In this study, H2 antigenic maps and radial graphs were generated using previously published data from H2 HA vaccinations of ferrets and seasonal influenza vaccinations of humans . The antigenic maps revealed a stark difference in clustering of HA antigens between the ferrets and humans, and the radial graphs showed specific antigen recognition varies greatly between different influenza preimmune ferrets . These maps also revealed the significant impact that different pre-existing immunities have on antigenic recogni...

  Abstract The spread of H5N1 clade 2.3.4.4b in dairy herds raises concerns about zoonotic transmission due to its high viral load in milk , a key contact point between livestock and humans . H5N1 clade 2.3.4.4b exhibits tropism for the mammary gland , with milk from infected animals containing high levels of infectious virus , posing potential risks to offspring via breastfeeding . Using a lactating ferret model , we demonstrate that mammary gland infection with bovine H5N1 transmits the virus to suckling kits , resulting in neonatal mortality . Viral RNA levels increased in milk and remained high in mammary tissue, with infected kits exhibiting elevated viral RNA in the oral and nasal cavities and feces . Additionally, we detected the H5N1 receptor, α2,3 sialic acid , in ferret and human mammary tissue . These data demonstrate that H5N1 clade 2.3.4.4b infection in lactating dams leads to mastitis-related disease and transmits to suckling pups, resulting in mortality among neonate...

  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 Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of coronavirus disease 2019 (COVID-19), is characterized by its high contagiousness. The COVID-19 pandemic has exerted profound impacts on human society . The persistent circulation of SARS-CoV-2 in human populations continues to pose re-exposure risks for both vaccinated individuals and those with prior natural infection. Against this epidemiological background, there is an urgent need to characterize the transmission dynamics of SARS-CoV-2 in the context of pre-existing immunity . Using a ferret infection model , this study systematically addresses critical scientific questions , including viral transmission efficiency , temporal patterns of transmissibility , and the ability of pre-existing immunity to mitigate reinfection and viral shedding. The findings provide robust experimental evidence for elucidating the transmission mechanisms of SARS-CoV-2 and offer scientific insights to info...

  Abstract Influenza is a global health concern, causing over 300,000 deaths worldwide annually . Current vaccines and natural infection mainly elicit antibodies against the variable head domain of the hemagglutinin (HA) glycoprotein. While these antibodies are highly neutralizing, the head domain constantly mutates due to selective pressure , causing the immune response to be strain-specific. Targeting the conserved HA stalk domain , however, has been shown to be a promising approach for a broadly protective vaccine . We previously demonstrated that presenting HA in an inverted orientation on virus-like particles (VLPs) significantly enhanced the induction of stalk-directed, cross-reactive antibodies compared to HA presented in a regular orientation. Here, we evaluated the protective efficacy of the inverted HA vaccine (VLP-HAinv) in mice against homologous, heterologous, and heterosubtypic influenza A virus challenges . VLP-HAinv vaccination in mice provided complete protection a...

  Abstract Background :  Monitoring antigenic drift in human influenza A viruses is essential for vaccine strain selection and ensuring protection against circulating strains. Antigenic drift is traditionally assessed using ferret antisera , which provide monospecific responses , and human vaccinee sera , which reflect exposure to multiple antigens. In this study we evaluated the pig as an alternative source of antisera to study antigenic drift compared to immune responses in ferrets and humans. We included seasonal influenza A(H1N1pdm09) human viruses that had shown different antigenic characteristics when using ferret or human antisera.  Methods :  Pairs of pigs were inoculated with six human A(H1N1)pdm09 viruses circulating between 2019 and 2023, a period of marked antigenic drift. Pig and ferret antisera were analysed by hemagglutination inhibition (HI) and virus neutralization (VN) assays.  Results :  Pigs were successfully infected with all strains, s...

  Abstract Since 2020, high pathogenicity avian influenza virus (HPAIV) infections in wild birds have been frequently reported . Because HPAIV infection has occasionally caused outbreaks in captive rare birds , application of antiviral drugs for treatment purposes against them has been considered from the perspective of conservation medicine . In this study, the therapeutic efficacy of baloxavir marboxil (BXM) was evaluated using a duck model to help establish the post-infection treatment for rare birds . Sixteen four-week-old ducks were divided into four groups and intranasally inoculated with the HPAIV strain A/crow/Hokkaido/0103B065/2022 ( H5N1 ). BXM was orally administered once daily at doses of 12.5, 2.5, 0.5, and 0 mg/kg to each of the four groups from 2 to 6 days post-infection. Blood samples were collected at 2, 8, and 24 hours after the initial BXM administration to measure the plasma concentrations of its active form, baloxavir acid (BXA). All ducks were monitored until ...

  ABSTRACT Common cold coronaviruses, such as OC43 and HKU1, typically cause mild respiratory infections in healthy people. However, they can lead to severe illness in high-risk groups , including immunocompromised individuals and older adults. Currently, there is no clinically approved vaccine to prevent infection by common cold coronaviruses. Here, we developed an mRNA vaccine expressing a stabilized spike protein derived from OC43 coronavirus and tested its efficacy in different challenge models in C57BL/6 mice . This novel OC43 vaccine elicited OC43-specific immune responses, as well as cross-reactive immune response against other embecoviruses , including HKU1 and mouse hepatitis virus (MHV-A59). Interestingly, this OC43 vaccine protected mice not only against a lethal OC43 infection but also against a distant embecovirus, MHV-A59. These findings provide insights for the development of common cold coronavirus vaccines, demonstrating their potential to protect against various c...

  Abstract Highly pathogenic avian influenza A(H5) viruses globally impact wild and domestic birds, and have caused severe infections in mammals, including humans , underscoring their pandemic potential . The antigenic evolution of the A(H5) haemagglutinin (HA) poses challenges for pandemic preparedness and vaccine design . Here the global antigenic evolution of the A(H5) HA was captured in a high-resolution antigenic map . The map was used to design immunogenic and antigenically central vaccine HA antigens, eliciting antibody responses that broadly cover the A(H5) antigenic space. In ferrets , a central antigen protected as well as homologous vaccines against heterologous infection with two antigenically distinct viruses. This work showcases the rational design of subtype-wide influenza A(H5) pre-pandemic vaccines and demonstrates the value of antigenic maps for the evaluation of vaccine-induced immune responses through antibody profiles. Source: Nature,  https://www.nature.c...

  Abstract Influenza A virus (IAV) infection during pregnancy is associated with stillbirth and preterm birth , possibly by disrupting placental and fetal immunity . To investigate this, pregnant pigtail macaques were inoculated with IAV [A/California/07/2009 (H1N1)] and examined at necropsy 5 days post-infection (N=11) versus uninfected controls (N=16). Stillbirth occurred in 18% of infected pregnancies but not in controls. While vertical transmission was not observed, low levels of viral RNA were detected in two placentas . Maternal IAV infection was associated with increased placental IL-1β and IFN-β levels and an upregulated type I interferon and integrated stress transcriptional response. Fetuses exposed to IAV had greater frequencies of innate immune cells in lymph nodes and CD4+ T cells in lungs . These results suggest that placental and fetal immune environments undergo immune activation independent of the severity of maternal lung infection. Influenza vaccination during pr...

  Highlights •  UniFluVec, an H1N1pdm vaccine candidate , includes NS1 and NEP modifications to boost attenuation and immunity. •  UniFluVec protects ferrets from H5N1 , enhancing clearance, limiting lung damage, and ensuring 100 % survival after one dose. •  Replication-deficient UniFluVec shows cross-protection , supporting its potential as a pre-pandemic intranasal vaccine. Abstract Background The emergence of new influenza strains with unpredictable antigenic properties poses a significant vaccination challenge. The increasing incidence of human H5 infections underscores the urgent need for effective pre-pandemic vaccines. Methods The UniFluVec and UniFluVec-wtNS1 viruses were designed as H1N1pdm vaccine candidates . Both viruses contained a heterologous A/Singapore/1/57-like (H2N2) NEP gene , which served as an attenuation factor . UniFluVec additionally carried a truncated to 124 amino acids NS1 gene , and an insertion of conserved influenza sequences. UniFluVe...

  Abstract In March 2024, a highly pathogenic avian influenza H5N1 (HPAI) clade 2.3.4.4b virus was identified in US dairy cows , with spillover to cats, poultry, and humans . Up to 30% of commercial pasteurized milk tested contained viral genome copies . The impact of residual viral remnants on host immunity is unknown. Orally ingested proteins can stimulate gut-associated lymphoid tissues , potentially inducing tolerance and altering responses to later infection. We found that milk pasteurization fully inactivated pandemic H1N1 and bovine H5N1 influenza viruses yet preserved hemagglutinin (HA) protein integrity. In mice , repeated oral exposure to inactivated virus did not alter mortality after H5N1 virus challenge. Preliminary data showed that naïve mice exposed to improperly pasteurized milk containing live H5N1 virus developed lethal infection , whereas prior H1N1 infection conferred protection . Mice with preexisting H1N1 immunity remained protected when challenged with bovine...

  Abstract Since its discovery in U.S. dairy cattle in early 2024, the highly pathogenic H5N1 avian influenza (clade 2.3.4.4b) has spread widely among herds, causing major economic losses. This zoonotic event emphasizes the urgent need for H5 vaccines that elicit strong, durable, cross-reactive immune responses in cattle , especially young calves. To address this, we immunized mice and cattle with a centralized consensus H5 vaccine, designed to localize to the central node of the human H5 phylogenetic tree . The vaccine was delivered using serotype-switched adenoviral vectors in a prime:boost regimen , combined with intramuscular and intranasal coadministration to target systemic and mucosal immunity and elicit strong humoral and cellular immune responses. This approach strategically integrates multiple innovative features: centralized consensus immunogens, mucosal targeting, and vector serotype switching that are aimed at maximizing immune protection against H5N1 viruses . Our res...

  Abstract Influenza A viruses remain a global health threat, yet no universal antibody therapy exists . Clinical programs have centered on neutralizing mAbs , only to be thwarted by strain specificity and rapid viral escape . We instead engineered three non-neutralizing IgG2a mAbs that target distinct, overlapping epitopes within the conserved N terminus of the M2 ectodomain (M2e). Combined at low dose, this “triple M2e-mAb” confers robust prophylactic and therapeutic protection in mice challenged with diverse human and zoonotic IAV strains, including highly pathogenic variants. Therapeutic efficacy depends on Fc-mediated effector activity via FcγRI, FcγRIII, and FcγRIV, rather than in vitro neutralization. Serial passaging in triple M2e-mAb–treated immunocompetent and immunodeficient hosts failed to generate viral escape mutants. Our findings redefine the influenza-specific antibody therapeutic design and support Fc-optimized, non-neutralizing M2e-mAbs as a broadly effective, mut...

  ABSTRACT Influenza A viruses continuously circulate among avian and swine species, posing a persistent threat to public health . The development of influenza candidate vaccine viruses (CVVs) plays a pivotal role in the global strategy for influenza pandemic preparedness . Safety-testing of CVVs for attenuation in ferrets represents a critical step that takes place prior to making these viruses available to vaccine manufacturers . Development of pathogenicity standards is needed to establish acceptable thresholds of disease so that CVV safety can be assessed without the need for comparison to the parental virus. To assess the capacity of diverse CVVs to cause pathogenesis in mammalian hosts , clinical and virological parameters were compiled from CVV assessments in ferrets conducted using consistent methods over approximately 20 years to identify disease parameters most reflective of attenuation compared to wild-type strains. These analyses revealed an overall reduction in ferret ...