Publications
14 results found
Najer A, Blight J, Ducker CB, et al., 2022, Potent virustatic polymer-lipid nanomimics block viral entry and inhibit malaria parasites in vivo, ACS Central Science, Vol: 8, Pages: 1238-1257, ISSN: 2374-7943
Infectious diseases continue to pose a substantial burden on global populations, requiring innovative broad-spectrum prophylactic and treatment alternatives. Here, we have designed modular synthetic polymer nanoparticles that mimic functional components of host cell membranes, yielding multivalent nanomimics that act by directly binding to varied pathogens. Nanomimic blood circulation time was prolonged by reformulating polymer–lipid hybrids. Femtomolar concentrations of the polymer nanomimics were sufficient to inhibit herpes simplex virus type 2 (HSV-2) entry into epithelial cells, while higher doses were needed against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Given their observed virustatic mode of action, the nanomimics were also tested with malaria parasite blood-stage merozoites, which lose their invasive capacity after a few minutes. Efficient inhibition of merozoite invasion of red blood cells was demonstrated both in vitro and in vivo using a preclinical rodent malaria model. We envision these nanomimics forming an adaptable platform for developing pathogen entry inhibitors and as immunomodulators, wherein nanomimic-inhibited pathogens can be secondarily targeted to sites of immune recognition.
Alves E, Benns H, Magnus L, et al., 2021, An extracellular redox signal triggers calcium release and impacts the asexual development of Toxoplasma gondii, Frontiers in Cellular and Infection Microbiology, Vol: 11, Pages: 1-14, ISSN: 2235-2988
The ability of an organism to sense and respond to environmental redox fluctuations relies on a signaling network that is incompletely understood in apicomplexan parasites such as Toxoplasma gondii. The impact of changes in redox upon the development of this intracellular parasite is not known. Here, we provide a revised collection of 58 genes containing domains related to canonical antioxidant function, with their encoded proteins widely dispersed throughout different cellular compartments. We demonstrate that addition of exogenous H2O2 to human fibroblasts infected with T.gondii triggers a Ca2+ flux in the cytosol of intracellular parasites that can induce egress. In line with existing models, egress triggered by exogenous H2O2 is reliant upon both Calcium-Dependent Protein Kinase 3 and diacylglycerol kinases. Finally, we show that the overexpression a glutaredoxin-roGFP2 redox sensor fusion protein in the parasitophorous vacuole severely impacts parasite replication. These data highlight the rich redox network that exists in T. gondii, evidencing a link betweenextracellular redox and intracellular Ca2+ signaling that can culminate in parasite egress. Our findings also indicate that the redox potential of the intracellular environment contributes to normal parasitegrowth. Combined, our findings highlight the important role of redox as an unexplored regulator of parasite biology.
Blight J, Sala K, Atcheson E, et al., 2021, Dissection-independent production of a Plasmodium sporozoites from whole mosquitoes, Life Science Alliance, Vol: 4, ISSN: 2575-1077
Progress towards a protective vaccine against malaria remains slow. To date, only limited protection has been routinely achieved following immunisation with either whole-parasite (sporozoite) or subunit-based vaccines. One major roadblock to vaccine progress, and to pre-erythrocytic parasite biology in general, is the continued reliance on manual salivary gland dissection for sporozoite isolation from infected mosquitoes. Here, we report development of a multi-step method, based on batch processing of homogenised whole mosquitoes, slurry, and density-gradient filtration, which combined with free-flow electrophoresis rapidly produces a pure, infective sporozoite inoculum. Human-infective Plasmodium falciparum and rodent-infective Plasmodium berghei sporozoites produced in this way are two- to threefold more infective than salivary gland dissection sporozoites in in vitro hepatocyte infection assays. In an in vivo rodent malaria model, the same P. berghei sporozoites confer sterile protection from mosquito-bite challenge when immunisation is delivered intravenously or 60–70% protection when delivered intramuscularly. By improving purity, infectivity, and immunogenicity, this method represents a key advancement in capacity to produce research-grade sporozoites, which should impact delivery of a whole-parasite based malaria vaccine at scale in the future.
Real E, Howick VM, Dahalan FA, et al., 2021, A single-cell atlas of <i>Plasmodium falciparum</i> transmission through the mosquito, NATURE COMMUNICATIONS, Vol: 12
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- Citations: 32
Da DF, McCabe R, Somé BM, et al., 2021, Detection of Plasmodium falciparum in laboratory-reared and naturally infected wild mosquitoes using near-infrared spectroscopy., Scientific Reports, Vol: 11, Pages: 10289-10289, ISSN: 2045-2322
There is an urgent need for high throughput, affordable methods of detecting pathogens inside insect vectors to facilitate surveillance. Near-infrared spectroscopy (NIRS) has shown promise to detect arbovirus and malaria in the laboratory but has not been evaluated in field conditions. Here we investigate the ability of NIRS to identify Plasmodium falciparum in Anopheles coluzzii mosquitoes. NIRS models trained on laboratory-reared mosquitoes infected with wild malaria parasites can detect the parasite in comparable mosquitoes with moderate accuracy though fails to detect oocysts or sporozoites in naturally infected field caught mosquitoes. Models trained on field mosquitoes were unable to predict the infection status of other field mosquitoes. Restricting analyses to mosquitoes of uninfectious and highly-infectious status did improve predictions suggesting sensitivity and specificity may be better in mosquitoes with higher numbers of parasites. Detection of infection appears restricted to homogenous groups of mosquitoes diminishing NIRS utility for detecting malaria within mosquitoes.
Alves E, Benns HJ, Magnus L, et al., 2021, An extracellular redox signal triggers calcium release and impacts the asexual development of <i>Toxoplasma gondii</i>
<jats:title>Abstract</jats:title><jats:p>The ability of an organism to sense and respond to environmental redox fluctuations relies on a signaling network that is incompletely understood in apicomplexan parasites such as <jats:italic>Toxoplasma gondii</jats:italic>. The impact of changes in redox upon the development of this intracellular parasite is not known. Here, we provide a revised collection of 58 genes containing domains related to canonical antioxidant function, with their encoded proteins widely dispersed throughout different cellular compartments. We demonstrate that addition of exogenous H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub> to human fibroblasts infected with <jats:italic>T. gondii</jats:italic> triggers a Ca<jats:sup>2+</jats:sup> flux in the cytosol of intracellular parasites that can induce egress. In line with existing models, egress triggered by exogenous H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub> is reliant upon both Calcium-Dependent Protein Kinase 3 and diacylglycerol kinases. Finally, we show that the overexpression a glutaredoxin-roGFP2 redox sensor fusion protein in the parasitophorous vacuole severely impacts parasite replication. These data highlight the rich redox network that exists in <jats:italic>T. gondii</jats:italic>, evidencing a link between extracellular redox and intracellular Ca<jats:sup>2+</jats:sup> signaling that can culminate in parasite egress. Our findings also indicate that the redox potential of the intracellular environment contributes to normal parasite growth. Combined, our findings highlight the important role of redox as an unexplored regulator of parasite biology.</jats:p>
Real E, Howick VM, Dahalan F, et al., 2020, A single-cell atlas of <i>Plasmodium falciparum</i> transmission through the mosquito
<jats:title>Abstract</jats:title><jats:p>Malaria parasites have a complex life cycle featuring diverse developmental strategies, each uniquely adapted to navigate specific host environments. Here we use single-cell transcriptomics to illuminate gene usage across the transmission cycle of the most virulent agent of human malaria – <jats:italic>Plasmodium falciparum</jats:italic>. We reveal developmental trajectories associated with the colonisation of the mosquito midgut and salivary glands and elucidate the transcriptional signatures of each transmissible stage. Additionally, we identify both conserved and nonconserved gene usage between human and rodent parasites, which point to both essential mechanisms in malaria transmission and species-specific adaptations potentially linked to host tropism. Together, the data presented here, which are made freely available via an interactive website, establish the most complete atlas of the <jats:italic>P. falciparum</jats:italic> transcriptional journey to date.</jats:p><jats:sec><jats:title>One sentence summary</jats:title><jats:p>Single-cell transcriptomics of <jats:italic>P. falciparum</jats:italic> transmission stages highlights developmental trajectories and gene usage.</jats:p></jats:sec>
Blight J, Sala KA, Atcheson E, et al., 2020, Dissection-independent production of a protective whole-sporozoite malaria vaccine
<jats:title>Abstract</jats:title><jats:p>Complete protection against human malaria challenge has been achieved using infected mosquitoes as the delivery route for immunization with<jats:italic>Plasmodium</jats:italic>parasites. Strategies seeking to replicate this efficacy with either a manufactured whole-parasite or subunit vaccine, however, have shown only limited success. A major roadblock to whole parasite vaccine progress and understanding of the human infective sporozoite form in general, is reliance on manual dissection for parasite isolation from infected mosquitoes. We report here the development of a four-step process based on whole mosquito homogenization, slurry and density-gradient filtration, combined with free-flow electrophoresis that is able to rapidly produce a pure, aseptic sporozoite inoculum from hundreds of mosquitoes. Murine<jats:italic>P. berghei</jats:italic>or human-infective<jats:italic>P. falciparum</jats:italic>sporozoites produced in this way are 2-3-fold more infective with<jats:italic>in vitro</jats:italic>hepatocytes and can confer sterile protection when immunized intravenously with subsequent challenge using a mouse malaria model. Critically, we can also demonstrate for the first time 60-70% protection when the same parasites are administered via intramuscular (i.m.) route. In developing a process amenable to industrialisation and demonstrating efficacy by i.m. route these data represent a major advancement in capacity to produce a whole parasite malaria vaccine at scale.</jats:p><jats:sec><jats:title>One-Sentence Summary</jats:title><jats:p>A four-step process for isolating pure infective malaria parasite sporozoites at scale from homogenized whole mosquitoes, independent of manual dissection, is able to produce a whole parasite vaccine inoculum that confers sterilizing protection.</jats:p></jats:sec>
Valero-Pacheco N, Blight J, Aldapa-Vega G, et al., 2020, Conservation of the OmpC Porin Among Typhoidal and Non-Typhoidal <i>Salmonella</i> Serovars, FRONTIERS IN IMMUNOLOGY, Vol: 10, ISSN: 1664-3224
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- Citations: 6
Hancock G, Blight J, Lopez-Camacho C, et al., 2019, A multi-genotype therapeutic human papillomavirus vaccine elicits potent T cell responses to conserved regions of early proteins, SCIENTIFIC REPORTS, Vol: 9, ISSN: 2045-2322
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- Citations: 14
Blight J, Alves E, Reyes-Sandoval A, 2019, Considering Genomic and Immunological Correlates of Protection for a Dengue Intervention, VACCINES, Vol: 7
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- Citations: 2
Lopez-Camacho C, Kim YC, Blight J, et al., 2019, Assessment of Immunogenicity and Neutralisation Efficacy of Viral-Vectored Vaccines Against Chikungunya Virus, VIRUSES-BASEL, Vol: 11, ISSN: 1999-4915
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- Citations: 28
Atcheson E, Bauza K, Salman AM, et al., 2018, Tailoring a Plasmodium vivax Vaccine To Enhance Efficacy through a Combination of a CSP Virus-Like Particle and TRAP Viral Vectors, Infection and Immunity, Vol: 86, ISSN: 0019-9567
<jats:title>ABSTRACT</jats:title><jats:p>Vivax malaria remains one of the most serious and neglected tropical diseases, with 132 to 391 million clinical cases per year and 2.5 billion people at risk of infection. A vaccine against <jats:named-content content-type="genus-species">Plasmodium vivax</jats:named-content> could have more impact than any other intervention, and the use of a vaccine targeting multiple antigens may result in higher efficacy against sporozoite infection than targeting a single antigen. Here, two leading <jats:named-content content-type="genus-species">P. vivax</jats:named-content> preerythrocytic vaccine candidate antigens, the <jats:named-content content-type="genus-species">P. vivax</jats:named-content> circumsporozoite protein (PvCSP) and the thrombospondin-related adhesion protein (PvTRAP) were delivered as a combined vaccine. This strategy provided a dose-sparing effect, with 100% sterile protection in mice using doses that individually conferred low or no protection, as with the unadjuvanted antigens PvTRAP (0%) and PvCSP (50%), and reached protection similar to that of adjuvanted components. Efficacy against malaria infection was assessed using a new mouse challenge model consisting of a double-transgenic <jats:named-content content-type="genus-species">Plasmodium berghei</jats:named-content> parasite simultaneously expressing PvCSP and PvTRAP used in mice immunized with the virus-like particle (VLP) Rv21 previously reported to induce high efficacy in mice using Matrix-M adjuvant, while PvTRAP was concomitantly administered in chimpanzee adenovirus and modified vaccinia virus Ankara (MVA) vectors (viral-vectored TRAP, or vvTRAP) to support effective induction of T cells. We examined immunity elicited by these vaccines in the context of two adjuvants approved for human use (AddaVax and Matrix-M). Matrix-M supported the highest anti-
Midega J, Blight J, Lombardo F, et al., 2014, Discovery and characterization of two Nimrod superfamily members in Anopheles gambiae, Pathogens and Global Health, Vol: 107, Pages: 463-474, ISSN: 2047-7724
Anti-bacterial proteins in mosquitoes are known to play an important modulatory role on immune responses to infections with human pathogens including malaria parasites. In this study we characterized two members of the Anopheles gambiae Nimrod superfamily, namely AgNimB2 and AgEater. We confirm that current annotation of the An. gambiae genome incorrectly identifies AgNimB2 and AgEater as a single gene, AGAP009762. Through in silico and experimental approaches, it has been shown that AgNimB2 is a secreted protein that mediates phagocytosis of Staphylococcus aureus but not of Escherichia coli bacteria. We also reveal that this function does not involve a direct interaction of AgNimB2 with S. aureus. Therefore, AgNimB2 may act downstream of complement-like pathway activation, first requiring bacterial opsonization. In addition, it has been shown that AgNimB2 has an anti-Plasmodium effect. Conversely, AgEater is a membrane-bound protein that either functions redundantly or is dispensable for phagocytosis of E. coli or S. aureus. Our study provides insights into the role of members of the complex Nimrod superfamily in An. gambiae, the most important African vector of human malaria.
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