In August 2022, a novel henipavirus (HNV) named Langya virus (LayV) was isolated from patients with severe pneumonic disease in China. This virus is closely related to Mòjiāng virus (MojV), and both ...are divergent from the bat-borne HNV members, Nipah (NiV) and Hendra (HeV) viruses. The spillover of LayV is the first instance of a HNV zoonosis to humans outside of NiV and HeV, highlighting the continuing threat this genus poses to human health. In this work, we determine the prefusion structures of MojV and LayV F proteins via cryogenic electron microscopy to 2.66 and 3.37 Å, respectively. We show that despite sequence divergence from NiV, the F proteins adopt an overall similar structure but are antigenically distinct as they do not react to known antibodies or sera. Glycoproteomic analysis revealed that while LayV F is less glycosylated than NiV F, it contains a glycan that shields a site of vulnerability previously identified for NiV. These findings explain the distinct antigenic profile of LayV and MojV F, despite the extent to which they are otherwise structurally similar to NiV. Our results carry implications for broad-spectrum HNV vaccines and therapeutics, and indicate an antigenic, yet not structural, divergence from prototypical HNVs.
...we are now presented with a unique window of opportunity to reassess these vaccines and decide whether they are optimal to combat future outbreaks. EBOV GP is present on the surface of the ...chimeric virus in place of VSV G. (B) Recent research has revealed that the EBOV GP (known atomic structure presented in red--PDB-5JQ3 36--and cryo-electron tomographic structure of the complete form in outline--EMD-6003 37) contains three critical neutralization sites found at the glycan cap, GP1/2 interface, and the stem region, respectively 32,38.
The representation of rainfall in space is important for hydrological modelling. Accurate estimation of rainfall is particularly challenging in mountainous regions where observations are often sparse ...relative to the spatial variability of rainfall. In these regions, orographic processes lead to complex patterns of rainfall enhancement and rain shadow depletion. This study tests Natural Neighbour Interpolation (NNI), ordinary kriging (OK) and ordinary cokriging (CK), to determine if CK improves rainfall interpolation during three extreme rainfall events. Three different elevation indices were considered as secondary variables for CK. Preliminary analysis using long‐term annual average rainfall totals, including additional high elevation rainfall observations, showed that CK with an effective elevation index (a directionally smoothed elevation, corrected for degree of ‘orographic processing’ and shifted to account for ‘wind‐drift’ of rainfall) as a secondary variable performed better than NNI and OK with an overall improvement of around 40%. Using rainfall totals for long‐term wind direction and wind speed rainfall classes, CK performance was variable but provided an improvement of approximately 15% for wind direction classes without an easterly wind component. For 15‐min timesteps during extreme rainfall events, there were comparatively small differences (cross‐validation using RMSE) between interpolation methods, partly attributed to having only relatively low elevation rainfall observations, providing weak constraint. Using cross‐validation and mean bias did, however, show an improvement for both high and low elevation observation classes. Importantly, cross‐variogram estimation provided differing cross‐validation results when estimated for different rainfall accumulation periods: 15‐min, hourly, daily and long‐term. Variograms and cross variograms estimated at a 15‐min timestep frequency were robust for many timesteps, but were difficult to fit automatically for others. Variograms estimated from longer periods were more reliably estimated, but tended to have lower variance and cross‐variance and longer correlation ranges producing a smoother interpolated rainfall field. Given the weak cross‐validation constraint, care must be taken in identifying the most appropriate method and variogram estimation period.
This study extends previous work using cokriging for interpolating rainfall in complex mountainous terrain. The primary novel aspect of this work is an ‘effective elevation’ secondary variable for cokriging that includes an index of directional ‘orographic processing.’ The work is also relatively novel in its investigation of high frequency (down to 15‐min) interpolation of rainfall during extreme events. Importantly, and contrary to many previous studies, relatively high correlations between the effective elevation index and 15‐min, and hourly, rainfall accumulations were found. The work also highlights that where rainfall observation sites are sparse and at relatively low elevations compared to the surrounding terrain, it is not sufficient to rely on simple cross‐validation results to evaluate different methods. This is the direct result of the weak constraint associated with the low elevation rainfall observations.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause coronavirus disease 2019 (COVID-19). Most individuals recover from SARS-CoV-2 infection, however, many continue to experience ...a cluster of persistent symptoms for months following resolution of acute disease; a syndrome that has been named Long-COVID. While the biological cause, or causes, of Long-COVID have not yet been confirmed, the main proposals have centred around either virus-induced autoimmunity or virus-induced tissue dysfunction. However, an alternative suggestion that a latent chronic infection could be responsible for the symptoms of Long-COVID has received minimal attention despite recent findings that SARS-CoV-2 genetic material and infections are detected in some individuals months following resolution of respiratory disease. Here we discuss literature supporting the possibility that Long-COVID occurs as a result of chronic SARS-CoV-2 infections.
Given the scale of the ongoing COVID-19 pandemic, the development of vaccines based on different platforms is essential, particularly in light of emerging viral variants, the absence of information ...on vaccine-induced immune durability, and potential paediatric use. We aimed to assess the safety and immunogenicity of an MF59-adjuvanted subunit vaccine for COVID-19 based on recombinant SARS-CoV-2 spike glycoprotein stabilised in a pre-fusion conformation by a novel molecular clamp (spike glycoprotein-clamp sclamp).
We did a phase 1, double-blind, placebo-controlled, block-randomised trial of the sclamp subunit vaccine in a single clinical trial site in Brisbane, QLD, Australia. Healthy adults (aged ≥18 to ≤55 years) who had tested negative for SARS-CoV-2, reported no close contact with anyone with active or previous SARS-CoV-2 infection, and tested negative for pre-existing SARS-CoV-2 immunity were included. Participants were randomly assigned to one of five treatment groups and received two doses via intramuscular injection 28 days apart of either placebo, sclamp vaccine at 5 μg, 15 μg, or 45 μg, or one dose of sclamp vaccine at 45 μg followed by placebo. Participants and study personnel, except the dose administration personnel, were masked to treatment. The primary safety endpoints included solicited local and systemic adverse events in the 7 days after each dose and unsolicited adverse events up to 12 months after dosing. Here, data are reported up until day 57. Primary immunogenicity endpoints were antigen-specific IgG ELISA and SARS-CoV-2 microneutralisation assays assessed at 28 days after each dose. The study is ongoing and registered with ClinicalTrials.gov, NCT04495933.
Between June 23, 2020, and Aug 17, 2020, of 314 healthy volunteers screened, 120 were randomly assigned (n=24 per group), and 114 (95%) completed the study up to day 57 (mean age 32·5 years SD 10·4, 65 54% male, 55 46% female). Severe solicited reactions were infrequent and occurred at similar rates in participants receiving placebo (two 8% of 24) and the SARS-CoV-2 sclamp vaccine at any dose (three 3% of 96). Both solicited reactions and unsolicited adverse events occurred at a similar frequency in participants receiving placebo and the SARS-CoV-2 sclamp vaccine. Solicited reactions occurred in 19 (79%) of 24 participants receiving placebo and 86 (90%) of 96 receiving the SARS-CoV-2 sclamp vaccine at any dose. Unsolicited adverse events occurred in seven (29%) of 24 participants receiving placebo and 35 (36%) of 96 participants receiving the SARS-CoV-2 sclamp vaccine at any dose. Vaccination with SARS-CoV-2 sclamp elicited a similar antigen-specific response irrespective of dose: 4 weeks after the initial dose (day 29) with 5 μg dose (geometric mean titre GMT 6400, 95% CI 3683–11 122), with 15 μg dose (7492, 4959–11 319), and the two 45 μg dose cohorts (8770, 5526–13 920 in the two-dose 45 μg cohort; 8793, 5570–13 881 in the single-dose 45 μg cohort); 4 weeks after the second dose (day 57) with two 5 μg doses (102 400, 64 857–161 676), with two 15 μg doses (74 725, 51 300–108 847), with two 45 μg doses (79 586, 55 430–114 268), only a single 45 μg dose (4795, 2858–8043). At day 57, 67 (99%) of 68 participants who received two doses of sclamp vaccine at any concentration produced a neutralising immune response, compared with six (25%) of 24 who received a single 45 μg dose and none of 22 who received placebo. Participants receiving two doses of sclamp vaccine elicited similar neutralisation titres, irrespective of dose: two 5 μg doses (GMT 228, 95% CI 146–356), two 15 μg doses (230, 170–312), and two 45 μg doses (239, 187–307).
This first-in-human trial shows that a subunit vaccine comprising mammalian cell culture-derived, MF59-adjuvanted, molecular clamp-stabilised recombinant spike protein elicits strong immune responses with a promising safety profile. However, the glycoprotein 41 peptide present in the clamp created HIV diagnostic assay interference, a possible barrier to widespread use highlighting the criticality of potential non-spike directed immunogenicity during vaccine development. Studies are ongoing with alternative molecular clamp trimerisation domains to ameliorate this response.
Coalition for Epidemic Preparedness Innovations, National Health and Medical Research Council, Queensland Government, and further philanthropic sources listed in the acknowledgments.
The human T-lymphotropic virus type 1 (HTLV-1) infects millions of people globally and is endemic to various resource-limited regions. Infections persist for life and are associated with increased ...susceptibility to opportunistic infections and severe diseases including adult T cell leukemia/lymphoma and HTLV-1-associated myelopathy-tropical spastic paraparesis. No HTLV-1-specific anti-retrovirals have been developed and it is unclear whether existing anti-retrovirals developed for treatment of human immunodeficiency virus (HIV) have efficacy against HTLV-1. To understand the structural basis for therapeutic binding, homology modelling and machine learning were used to develop a structural model of the HTLV-1 reverse transcriptase. With this, molecular docking experiments using a panel of FDA-approved inhibitors of viral reverse transcriptases to assess their capacity for binding, and in turn, inhibition. Importantly, nucleoside/nucleotide reverse transcriptase inhibitor but not non-nucleoside reverse transcriptase inhibitors were predicted to bind the HTLV-1 reverse transcriptase, with similar affinity to HIV-1 reverse transcriptase. By strengthening the rationale for clinical testing of therapies such as tenofovir alafenamide, zidovudine, lamivudine, and azvudine for treatment of HTLV-1, this study has demonstrated the power of in silico structural biology approaches in drug design and therapeutic testing.
Coronavirus disease-2019 (COVID-19) is primarily a respiratory disease, however, an increasing number of reports indicate that SARS-CoV-2 infection can also cause severe neurological manifestations, ...including precipitating cases of probable Parkinson's disease. As microglial NLRP3 inflammasome activation is a major driver of neurodegeneration, here we interrogated whether SARS-CoV-2 can promote microglial NLRP3 inflammasome activation. Using SARS-CoV-2 infection of transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) as a COVID-19 pre-clinical model, we established the presence of virus in the brain together with microglial activation and NLRP3 inflammasome upregulation in comparison to uninfected mice. Next, utilising a model of human monocyte-derived microglia, we identified that SARS-CoV-2 isolates can bind and enter human microglia in the absence of viral replication. This interaction of virus and microglia directly induced robust inflammasome activation, even in the absence of another priming signal. Mechanistically, we demonstrated that purified SARS-CoV-2 spike glycoprotein activated the NLRP3 inflammasome in LPS-primed microglia, in a ACE2-dependent manner. Spike protein also could prime the inflammasome in microglia through NF-κB signalling, allowing for activation through either ATP, nigericin or α-synuclein. Notably, SARS-CoV-2 and spike protein-mediated microglial inflammasome activation was significantly enhanced in the presence of α-synuclein fibrils and was entirely ablated by NLRP3-inhibition. Finally, we demonstrate SARS-CoV-2 infected hACE2 mice treated orally post-infection with the NLRP3 inhibitory drug MCC950, have significantly reduced microglial inflammasome activation, and increased survival in comparison with untreated SARS-CoV-2 infected mice. These results support a possible mechanism of microglial innate immune activation by SARS-CoV-2, which could explain the increased vulnerability to developing neurological symptoms akin to Parkinson's disease in COVID-19 infected individuals, and a potential therapeutic avenue for intervention.
There are no approved flaviviral therapies and the development of vaccines against flaviruses has the potential of being undermined by antibody-dependent enhancement (ADE). The flavivirus ...nonstructural protein 1 (NS1) is a promising vaccine antigen with low ADE risk but has yet to be explored as a broad-spectrum therapeutic antibody target. Here, we provide the structural basis of NS1 antibody cross-reactivity through cocrystallization of the antibody 1G5.3 with NS1 proteins from dengue and Zika viruses. The 1G5.3 antibody blocks multi-flavivirus NS1-mediated cell permeability in disease-relevant cell lines, and therapeutic application of 1G5.3 reduces viremia and improves survival in dengue, Zika, and West Nile virus murine models. Finally, we demonstrate that 1G5.3 protection is independent of effector function, identifying the 1G5.3 epitope as a key site for broad-spectrum antiviral development.
Abstract
Koala retrovirus is a recently endogenized retrovirus associated with the onset of neoplasia and infectious disease in koalas. There are currently twelve described KoRV subtypes (KoRV-A to ...I, K–M), most of which were identified through recently implemented deep sequencing methods which reveal an animals’ overall KoRV profile. This approach has primarily been carried out on wild koala populations around Australia, with few investigations into the whole-population KoRV profile of captive koala colonies to date. This study conducted deep sequencing on 64 captive koalas of known pedigree, housed in three institutions from New South Wales and South-East Queensland, to provide a detailed analysis of KoRV genetic diversity and transmission. The final dataset included 93 unique KoRV sequences and the first detection of KoRV-E within Australian koala populations. Our analysis suggests that exogenous transmission of KoRV-A, B, D, I and K primarily occurs between dam and joey. Detection of KoRV-D in a neonate sample raises the possibility of this transmission occurring in utero. Overall, the prevalence and abundance of KoRV subtypes was found to vary considerably between captive populations, likely due to their different histories of animal acquisition. Together these findings highlight the importance of KoRV profiling for captive koalas, in particular females, who play a primary role in KoRV exogenous transmission.
Repeated retroviral infections of vertebrate germlines have made endogenous retroviruses ubiquitous features of mammalian genomes. However, millions of years of evolution obscure many of the ...immediate repercussions of retroviral endogenisation on host health. Here we examine retroviral endogenisation during its earliest stages in the koala (Phascolarctos cinereus), a species undergoing germline invasion by koala retrovirus (KoRV) and affected by high cancer prevalence. We characterise KoRV integration sites (IS) in tumour and healthy tissues from 10 koalas, detecting 1002 unique IS, with hotspots of integration occurring in the vicinity of known cancer genes. We find that tumours accumulate novel IS, with proximate genes over-represented for cancer associations. We detect dysregulation of genes containing IS and identify a highly-expressed transduced oncogene. Our data provide insights into the tremendous mutational load suffered by the host during active retroviral germline invasion, a process repeatedly experienced and overcome during the evolution of vertebrate lineages.
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