Transcriptional profiling of immune responses in NHPs after low-dose, VSV-based vaccination against Marburg virus.

Infection with Marburg virus (MARV), the causative agent of Marburg virus disease (MVD), results in haemorrhagic disease and high case fatality rates (>40%) in humans. Despite its public health relevance, there are no licensed vaccines or therapeutics to prevent or treat MVD. A vesicular stomatitis virus (VSV)-based vaccine expressing the MARV glycoprotein (VSV-MARV) is currently in clinical development. Previously, a single 10 million PFU dose of VSV-MARV administered 1-5 weeks before lethal MARV challenge conferred uniform protection in nonhuman primates (NHPs), demonstrating fast-acting potential. Additionally, our group recently demonstrated that even a low dose VSV-MARV (1000 PFU) protected NHPs when given 7 days before MARV challenge. In this study, we longitudinally profiled the transcriptional responses of NHPs vaccinated with this low dose of VSV-MARV either 14 or 7 days before lethal MARV challenge. NHPs vaccinated 14 days before challenge presented with transcriptional changes consistent with an antiviral response before challenge. Limited gene expression changes were observed in the group vaccinated 7 days before challenge. After challenge, genes related to lymphocyte-mediated immunity were only observed in the group vaccinated 14 days before challenge, indicating that the length of time between vaccination and challenge influenced gene expression. Our results indicate that a low dose VSV-MARV elicits distinct immune responses that correlate with protection against MVD. A low dose of VSV-MARV should be evaluated in clinical rails as it may be an option to deliver beneficial public health outcomes to more people in the event of future outbreaks.

Metabolic Strategies Shared by Basement Residents of the Lost City Hydrothermal Field.

Alkaline fluids venting from chimneys of the Lost City hydrothermal field flow from a potentially vast microbial habitat within the seafloor where energy and organic molecules are released by chemical reactions within rocks uplifted from Earth's mantle. In this study, we investigated hydrothermal fluids venting from Lost City chimneys as windows into subseafloor environments where the products of geochemical reactions, such as molecular hydrogen (H2), formate, and methane, may be the only available sources of energy for biological activity. Our deep sequencing of metagenomes and metatranscriptomes from these hydrothermal fluids revealed a few key species of archaea and bacteria that are likely to play critical roles in the subseafloor microbial ecosystem. We identified a population of Thermodesulfovibrionales (belonging to phylum Nitrospirota) as a prevalent sulfate-reducing bacterium that may be responsible for much of the consumption of H2 and sulfate in Lost City fluids. Metagenome-assembled genomes (MAGs) classified as Methanosarcinaceae and Candidatus Bipolaricaulota were also recovered from venting fluids and represent potential methanogenic and acetogenic members of the subseafloor ecosystem. These genomes share novel hydrogenases and formate dehydrogenase-like sequences that may be unique to hydrothermal environments where H2 and formate are much more abundant than carbon dioxide. The results of this study include multiple examples of metabolic strategies that appear to be advantageous in hydrothermal and subsurface alkaline environments where energy and carbon are provided by geochemical reactions. IMPORTANCE The Lost City hydrothermal field is an iconic example of a microbial ecosystem fueled by energy and carbon from Earth's mantle. Uplift of mantle rocks into the seafloor can trigger a process known as serpentinization that releases molecular hydrogen (H2) and creates unusual environmental conditions where simple organic carbon molecules are more stable than dissolved inorganic carbon. This study provides an initial glimpse into the kinds of microbes that live deep within the seafloor where serpentinization takes place, by sampling hydrothermal fluids exiting from the Lost City chimneys. The metabolic strategies that these microbes appear to be using are also shared by microbes that inhabit other sites of serpentinization, including continental subsurface environments and natural springs. Therefore, the results of this study contribute to a broader, interdisciplinary effort to understand the general principles and mechanisms by which serpentinization-associated processes can support life on Earth and perhaps other worlds.

A Lectin Disrupts Vector Transmission of a Grapevine Ampelovirus.

Grapevine leafroll disease is one of the most important virus diseases of grapevines and occurs in every major grape-growing region of the world. The vector-transmission mechanisms of the causative agent, Grapevine leafroll-associated virus 3 (GLRaV-3), remain poorly understood. We show that the vine mealybug, Planococcus ficus, feeds through a membrane feeding system on GLRaV-3 viral purifications from both V. vinifera and N. benthamiana and transmits the virus to test plants from plants from both species. Building on this strategy, we used an immunofluorescence approach to localize virions to two retention sites in P. ficus mouthparts. Assays testing molecules capable of blocking virus transmission demonstrated that GLRaV-3-transmission by P. ficus could be disrupted. Our results indicate that our membrane feeding system and transmission-blocking assays are a valid approach and can be used to screen other candidate blocking molecules.

From Berlin to London: HIV-1 Reservoir Reduction Following Stem Cell Transplantation.

PURPOSE OF REVIEW: Few interventional strategies lead to significant reductions in HIV-1 reservoir size or prolonged antiretroviral (ART)-free remission. Allogeneic stem cell transplantations (SCT) with or without donor cells harboring genetic mutations preventing functional expression of CCR5, an HIV coreceptor, lead to dramatic reductions in residual HIV burden. However, the mechanisms by which SCT reduces viral reservoirs and leads to a potential functional HIV cure are not well understood. RECENT FINDINGS: A growing number of studies involving allogeneic SCT in people with HIV are emerging, including those with and without transplants involving CCR5Δ32/Δ32 mutations. Donor cells resistant to HIV entry are likely required in order to achieve permanent ART-free viral remission. However, dramatic reductions in the HIV reservoir secondary to beneficial graft-versus-host effects may lead to loss of HIV detection in blood and various tissues and lead to prolonged time to HIV rebound in individuals with wild-type CCR5 donors. Studies of SCT recipients and those who started very early ART during hyperacute infection suggest that dramatic reductions in reservoir size or restriction of initial reservoir seeding may lead to 8-10 months of time prior to eventual, and rapid, HIV recrudescence. Studies of allogeneic SCT in people with HIV have provided important insights into the size and nature of the HIV reservoir, and have invigorated other gene therapies to achieve HIV cure.

Comparison of two different host plant genera responding to grapevine leafroll-associated virus 3 infection.

Grapevine leafroll-associated virus 3 (GLRaV-3) is one of the most important viruses of grapevine but, despite this, there remain several gaps in our understanding of its biology. Because of its narrow host range - limited to Vitis species - and because the virus is restricted to the phloem, most GLRaV-3 research has concentrated on epidemiology and the development of detection assays. The recent discovery that GLRaV-3 can infect Nicotiana benthamiana, a plant model organism, makes new opportunities available for research in this field. We used RNA-seq to compare both V. vinifera and P1/HC-Pro N. benthamiana host responses to GLRaV-3 infection. Our analysis revealed that the majority of DEGs observed between the two hosts were unique although responses between the two hosts also showed several shared gene expression results. When comparing gene expression patterns that were shared between the two hosts, we observed the downregulation of genes associated with stress chaperones, and the induction of gene families involved in primary plant physiological processes. This is the first analysis of gene expression profiles beyond Vitis to mealybug-transmitted GLRaV-3 and demonstrates that N. benthamiana could serve as a useful tool for future studies of GLRaV-3-host interactions.

Tunable Fano-Resonant Metasurfaces on a Disposable Plastic-Template for Multimodal and Multiplex Biosensing.

Metasurfaces are engineered nanostructured interfaces that extend the photonic behavior of natural materials, and they spur many breakthroughs in multiple fields, including quantum optics, optoelectronics, and biosensing. Recent advances in metasurface nanofabrication enable precise manipulation of light-matter interactions at subwavelength scales. However, current fabrication methods are costly and time-consuming and have a small active area with low reproducibility due to limitations in lithography, where sensing nanosized rare biotargets requires a wide active surface area for efficient binding and detection. Here, a plastic-templated tunable metasurface with a large active area and periodic metal-dielectric layers to excite plasmonic Fano resonance transitions providing multimodal and multiplex sensing of small biotargets, such as proteins and viruses, is introduced. The tunable Fano resonance feature of the metasurface is enabled via chemical etching steps to manage nanoperiodicity of the plastic template decorated with plasmonic layers and surrounding dielectric medium. This metasurface integrated with microfluidics further enhances the light-matter interactions over a wide sensing area, extending data collection from 3D to 4D by tracking real-time biomolecular binding events. Overall, this work resolves cost- and complexity-related large-scale fabrication challenges and improves multilayer sensitivity of detection in biosensing applications.

Cerebrospinal fluid soluble CD30 elevation despite suppressive antiretroviral therapy in individuals living with HIV-1.

OBJECTIVES: The aim of this study was to assess soluble CD30 (sCD30), a protein that colocalises with HIV-1 RNA and DNA in lymphoid cells and tissues, in cerebrospinal fluid (CSF) as a marker of HIV-1 infection in the central nervous system (CNS). METHODS: This was a cross-sectional study using archived samples from two clinical cohorts. Soluble CD30 concentrations were measured in paired CSF and plasma from untreated viraemic individuals (n=52), individuals on suppressive antiretroviral therapy (ART) (n=33), HIV-1 controllers (n=10), participants with CSF HIV-1 'escape' (n=11) and controls without HIV-1 infection (n=16). Nonparametric tests were used to compare levels across groups and evaluate correlations with HIV-1 RNA, CSF neurofilament light chain protein (NFL) and neopterin. RESULTS: Compared with controls (median 30 ng/mL, interquartile range [IRQ] 23-50), plasma sCD30 levels were elevated in viraemic participants (75 ng/mL, 52-116; P<0.001), but not in those on suppressive ART (38 ng/mL, 32-62). In contrast, CSF sCD30 levels were elevated in ART-suppressed individuals (34 ng/mL, 19-46; P=0.001) and in those with CSF 'escape' (33 ng/mL, 27-40; P=0.004) compared with controls (18 ng/mL, 11-23), but not in untreated viraemic individuals. No association was observed between CSF sCD30 and plasma HIV-1 RNA, concurrent or nadir CD4+ T cell count, duration of infection or plasma sCD30. CSF sCD30 correlated with CSF NFL (r=0.34, P=0.001). CONCLUSIONS: In contrast to plasma, sCD30 levels are elevated in the CSF of individuals with HIV-1 infection who are on suppressive ART. Elevated levels of sCD30 in the CSF may be an indicator of persistent CNS HIV-1 infection, although the mechanism underlying this elevation warrants further investigation.

Circulating CD30+CD4+ T Cells Increase Before Human Immunodeficiency Virus Rebound After Analytical Antiretroviral Treatment Interruption.

BACKGROUND: Identification of nonviral markers of human immunodeficiency virus (HIV) infection that increase before viral rebound during analytical treatment interruption (ATI) may affect HIV persistence research. We previously showed that HIV ribonucleic acid (RNA) is enriched in CD30+CD4+ T cells in many individuals. Here, we studied CD30+CD4+ T-cell dynamics before ATI, during ATI (before detectable plasma RNA), and after HIV rebound. METHODS: Peripheral blood mononuclear cells from 23 participants collected longitudinally from 5 Adult AIDS Clinical Trials Group studies incorporating ATI were included in this study. Flow cytometric characterization of expression of CD30 and markers of T-cell activation and exhaustion were performed along with HIV-1 RNA and deoxyribonucleic acid quantification and measurement of soluble plasma CD30 and CD30 ligand. RESULTS: The percentage of CD4+ T cells expressing CD30 significantly increased from pre-ATI to postinterruption time points before detectible viremia (1.65 mean relative increase, P = .005). Seventy-seven percent of participants experienced an increase in CD30+ cells before viral rebound. In contrast, there were no significant differences between pre-ATI and postinterruption pre-rebound time points in percentages of lymphocytes expressing CD69, CD38/HLA-DR, or PD-1 until after HIV recrudescence. CONCLUSIONS: CD30 may be a surrogate marker of early replication or viral transcriptional activity before detection by routine peripheral blood sampling.

Infection and Colonization of Nicotiana benthamiana by Grapevine leafroll-associated virus 3.

Grapevine leafroll disease is an increasing problem in all grape-growing regions of the world. The most widespread agent of the disease, Grapevine leafroll-associated virus 3 (GLRaV-3), has never been shown to infect species outside of the genus Vitis. Virus transmission to several plant species used as model systems was tested using the vine mealybug, Planococcus ficus. We show that GLRaV-3 is able to infect Nicotiana benthamiana. Working with GLRaV-3 infected N. benthamiana revealed distinct advantages in comparison with its natural host Vitis vinifera, yielding both higher viral protein and virion concentrations in western blot and transmission electron microscopy observations, respectively. Immunogold labelling of thin sections through N. benthamiana petioles revealed filamentous particles in the phloem cells of GLRaV-3 positive plants. Comparison of assembled whole genomes from GLRaV-3 infected V. vinifera vs. N. benthamiana revealed substitutions in the 5' UTR. These results open new avenues and opportunities for GLRaV-3 research.

Venom variation during prey capture by the cone snail, Conus textile.

Observations of the mollusc-hunting cone snail Conus textile during feeding reveal that prey are often stung multiple times in succession. While studies on the venom peptides injected by fish-hunting cone snails have become common, these approaches have not been widely applied to the analysis of the injected venoms from mollusc-hunters. We have successfully obtained multiple injected venom samples from C. textile individuals, allowing us to investigate venom compositional variation during prey capture. Our studies indicate that C. textile individuals alter the composition of prey-injected venom peptides during single feeding events. The qualitative results obtained by MALDI-ToF mass spectrometry are mirrored by quantitative changes in venom composition observed by reverse-phase high performance liquid chromatography. While it is unclear why mollusc-hunting cone snails inject prey multiple times prior to engulfment, our study establishes for the first time a link between this behavior and compositional changes of the venom during prey capture. Changes in venom composition during hunting may represent a multi-step strategy utilized by these venomous animals to slow and incapacitate prey prior to engulfment.