Vector Choice Determines Immunogenicity and Potency of Genetic Vaccines against Angola Marburg Virus in Nonhuman Primates

The immunogenicity and durability of genetic vaccines are influenced by the composition of gene inserts and choice of delivery vector. DNA vectors are a promising vaccine approach showing efficacy when combined in prime-boost regimens with recombinant protein or viral vectors, but they have shown limited comparative efficacy as a stand-alone platform in primates, due possibly to suboptimal gene expression or cell targeting. Here, regimens using DNA plasmids modified for optimal antigen expression and recombinant adenovirus (rAd) vectors, all encoding the glycoprotein (GP) gene from Angola Marburg virus (MARV), were compared for their ability to provide immune protection against lethal MARV Angola infection. Heterologous DNA-GP/rAd5-GP prime-boost and single-modality rAd5-GP, as well as the DNA-GP-only vaccine, prevented death in all vaccinated subjects after challenge with a lethal dose of MARV Angola. The DNA/DNA vaccine induced humoral responses comparable to those induced by a single inoculation with rAd5-GP, as well as CD4⁺ and CD8⁺ cellular immune responses, with skewing toward CD4⁺ T-cell activity against MARV GP. Vaccine regimens containing rAd-GP, alone or as a boost, exhibited cellular responses with CD8⁺ T-cell dominance. Across vaccine groups, CD8⁺ T-cell subset dominance comprising cells exhibiting a tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ) double-positive functional phenotype was associated with an absence or low frequency of clinical symptoms, suggesting that both the magnitude and functional phenotype of CD8⁺ T cells may determine vaccine efficacy against infection by MARV Angola.The filoviruses Marburgvirus (MARV) and Ebolavirus (EBOV) are endemic primarily to central Africa and cause a severe form of viral hemorrhagic fever. Of all the filovirus strains or species, the Angola strain of MARV is associated with the highest mortality rate (90%) in humans observed to date (26). An increase in natural filovirus outbreak frequency over the past decade and the potential for use to cause deliberate human mortality have focused attention on the need for therapeutics and vaccines against filoviruses. While regulatory pathways have been proposed to facilitate licensing of a preventive vaccine against potently lethal pathogens such as these, there is as yet no licensed vaccine for use in humans, and efforts remain targeted to the optimization of vaccine performance in nonhuman primates (NHP) since this animal model recapitulates many aspects of disease pathogenesis observed in humans.Genetic vaccines are a promising approach for immunization against pathogens that are rapidly changing due to natural evolution, cross-species transmission, or intentional modification. Gene-based vaccines are produced rapidly and can be delivered by a variety of vectors. DNA vectors are advantageous because they are inherently safe and stable and can be used repeatedly without inducing antivector immune responses. However, while filovirus DNA vaccines have demonstrated efficacy in small animal models, efforts to induce protective immunity by injection of plasmid DNA alone into NHP have yielded less encouraging results. EBOV DNA vectors generate immune protection in mice and guinea pigs, but this has not been demonstrated in NHP unless DNA immunization is boosted with a viral vector vaccine (23). MARV DNA fully protects mice and guinea pigs but provides only partial protection in NHP (17). The discordant results between rodent and primate species may be due to the use of slightly modified infectious challenge viruses in rodent models or may reflect underlying differences in vaccine performance and the mechanisms of immune protection between rodents and NHP.In the current study, we examined whether DNA plasmid-based vaccines could be improved to increase potency in NHP and compared immunogenicity of this vaccine modality with those of viral vector and prime-boost approaches. DNA-vectored vaccines were modified by codon optimizing gene target inserts for enhanced expression in primates. These vectors induced antigen-specific cellular and humoral immune responses similar to immunization using a recombinant adenoviral vector and provided protection after lethal challenge with MARV Angola. However, macaques vaccinated with DNA vectors exhibited clinical symptoms associated with MARV hemorrhagic fever (MHF) that were absent in NHP receiving a single inoculation with recombinant adenovirus (rAd) vectors, suggesting qualitative differences in the immune responses elicited by the different modalities.     

Density, distribution and mobility of surface anions on a normal/transformed cell pair

The distribution and mobility of cell surface anions was investigated on low passage cultures of secondary BALB/c embryonic fibroblasts and their SV40-transformed counterparts (VLM cells) using polycationized ferritin (PCF) as a label. While the absolute number of anions/nm² of membrane was equivalent on the two cell types, the topographical distribution and mobility of these anions was strikingly different. After pulse-labeling with PCF at 37 °C, anions on BALB/c fibroblasts occurred in large piled-up clusters separated by extensive areas of membrane ( = 0.47 μm) free of negative charges. Labeling at 4 °C reduced the degree of “piling up” within the clusters, but the intercluster spacing was maintained indicating that the anions have short-range mobility in the membrane and can be cross-linked into a tight lattice at 37 °C. These anions do not, however, demonstrate any long-range mobility during a 20 min post-label incubation in PBS. In contrast, anions on VLM cells are inherently present in a random configuration of microclusters and single anions with relatively small ( = 0.09 μm) intervening areas of low charge density. Short-range mobility of surface anions is not displayed, presumably as a result of the inter-site distance, but long-range mobility is indicated by the formation of large site clusters following a 20 min incubation in PBS after pulse-labeling. Very mild proteolysis of BALB/c fibroblasts induces a change in the topography of surface anions toward the random configuration typical of VLM cells. These data are discussed in relation to altered social interactions between tumor cells which may be influenced by cell-cell adhesion characteristics.     

Integrating systemic and molecular levels to infer key drivers sustaining metabolic adaptations

Metabolic adaptations to complex perturbations, like the response to pharmacological treatments in multifactorial diseases such as cancer, can be described through measurements of part of the fluxes and concentrations at the systemic level and individual transporter and enzyme activities at the molecular level. In the framework of Metabolic Control Analysis (MCA), ensembles of linear constraints can be built integrating these measurements at both systemic and molecular levels, which are expressed as relative differences or changes produced in the metabolic adaptation. Here, combining MCA with Linear Programming, an efficient computational strategy is developed to infer additional non-measured changes at the molecular level that are required to satisfy these constraints. An application of this strategy is illustrated by using a set of fluxes, concentrations, and differentially expressed genes that characterize the response to cyclin-dependent kinases 4 and 6 inhibition in colon cancer cells. Decreases and increases in transporter and enzyme individual activities required to reprogram the measured changes in fluxes and concentrations are compared with down-regulated and up-regulated metabolic genes to unveil those that are key molecular drivers of the metabolic response.     

Jelly-falls historic and recent observations: a review to drive future research directions

The biological pump describes the transport of particulate matter from the sea surface to the ocean’s interior including the seabed. The contribution by gelatinous zooplankton bodies as particulate organic matter (POM) vectors (“jelly-falls”) has been neglected owing to technical and spatiotemporal sampling limitations. Here, we assess the existing evidence on jelly-falls from early ocean observations to present times. The seasonality of jelly-falls indicates that they mostly occur after periods of strong upwelling and/or spring blooms in temperate/subpolar zones and during late spring/early summer. A conceptual model helps to define a jelly-fall based on empirical and field observations of biogeochemical and ecological processes. We then compile and discuss existing strategic and observational oceanographic techniques that could be implemented to further jelly-falls research. Seabed video- and photography-based studies deliver the best results, and the correct use of fishing techniques, such as trawling, could provide comprehensive regional datasets. We conclude by considering the possibility of increased gelatinous biomasses in the future ocean induced by upper ocean processes favouring their populations, thus increasing jelly-POM downward transport. We suggest that this could provide a “natural compensation” for predicted losses in pelagic POM with respect to fuelling benthic ecosystems.     

Distribution and habitat associations of billfish and swordfish larvae across mesoscale features in the Gulf of Mexico

Ichthyoplankton surveys were conducted in surface waters of the northern Gulf of Mexico (NGoM) over a three-year period (2006-2008) to determine the relative value of this region as early life habitat of sailfish (Istiophorus platypterus), blue marlin (Makaira nigricans), white marlin (Kajikia albida), and swordfish (Xiphias gladius). Sailfish were the dominant billfish collected in summer surveys, and larvae were present at 37.5% of the stations sampled. Blue marlin and white marlin larvae were present at 25.0% and 4.6% of the stations sampled, respectively, while swordfish occurred at 17.2% of the stations. Areas of peak production were detected and maximum density estimates for sailfish (22.09 larvae 1000 m(-2)) were significantly higher than the three other species: blue marlin (9.62 larvae 1000 m(-2)), white marlin (5.44 larvae 1000 m(-2)), and swordfish (4.67 larvae 1000 m(-2)). The distribution and abundance of billfish and swordfish larvae varied spatially and temporally, and several environmental variables (sea surface temperature, salinity, sea surface height, distance to the Loop Current, current velocity, water depth, and Sargassum biomass) were deemed to be influential variables in generalized additive models (GAMs). Mesoscale features in the NGoM affected the distribution and abundance of billfish and swordfish larvae, with densities typically higher in frontal zones or areas proximal to the Loop Current. Habitat suitability of all four species was strongly linked to physicochemical attributes of the water masses they inhabited, and observed abundance was higher in slope waters with lower sea surface temperature and higher salinity. Our results highlight the value of the NGoM as early life habitat of billfishes and swordfish, and represent valuable baseline data for evaluating anthropogenic effects (i.e., Deepwater Horizon oil spill) on the Atlantic billfish and swordfish populations.     

Effects of heterogeneous interaction strengths on food web complexity

Using a bioenergetic model we show that the pattern of foraging preferences greatly determines the complexity of the resulting food webs. By complexity we refer to the degree of richness of food-web architecture, measured in terms of some topological indicators (number of persistent species and links, connectance, link density, number of trophic levels, and frequency of weak links). The poorest food-web architecture is found for a mean-field scenario where all foraging preferences are assumed to be the same. Richer food webs appear when foraging preferences depend on the trophic position of species. Food-web complexity increases with the number of basal species. We also find a strong correlation between the complexity of a trophic module and the complexity of entire food webs with the same pattern of foraging preferences.     

Enteroviral and Mumps Meningitis in Toronto, 1963

Virological investigations of 115 children with the aseptic meningitis syndrome during 1963 resulted in the isolation of enteroviruses from cerebrospinal fluid (CSF) and/or feces of 21 of 48 children who had no association with mumps. For the third successive year, Echo 9 was the dominant enterovirus in cases of aseptic meningitis in Toronto children, but no rashes were associated with Echo 9 meningitis during 1963, in contradistinction to previous years. Mumps virus was isolated from CSF of 25 patients by inoculation of rhesus monkey kidney cultures, and rising or elevated mumps antihemagglutinin titres in paired sera from a further 33 cases provided laboratory evidence of infection with mumps virus in 58 of 67 patients with mumps meningoencephalitis. No enlargement of salivary glands was noted in 20 laboratory-proved cases of mumps meningoencephalitis. Enteroviral meningitis occurred principally during summer, but the peak of mumps meningoencephalitis occurred during late winter.     

Pneumococcal Carriage in Children under Five Years in Uganda-Will Present Pneumococcal Conjugate Vaccines Be Appropriate?

BackgroundPneumonia is the major cause of death in children globally, with more than 900,000 deaths annually in children under five years of age. Streptococcus pneumoniae causes most deaths, most often in the form of community acquired pneumonia. Pneumococcal conjugate vaccines (PCVs) are currently being implemented in many low-income countries. PCVs decrease vaccine-type pneumococcal carriage, a prerequisite for invasive pneumococcal disease, and thereby affects pneumococcal disease and transmission. In Uganda, PCV was launched in 2014, but baseline data is lacking for pneumococcal serotypes in carriage.ObjectivesTo study pneumococcal nasopharyngeal carriage and serotype distribution in children under 5 years of age prior to PCV introduction in UgandaMethodsThree cross-sectional pneumococcal carriage surveys were conducted in 2008, 2009 and 2011, comprising respectively 150, 587 and 1024 randomly selected children aged less than five years from the Iganga/Mayuge Health and Demographic Surveillance Site. The caretakers were interviewed about illness history of the child and 1723 nasopharyngeal specimens were collected. From these, 927 isolates of S. pneumoniae were serotyped.ResultsOverall, the carriage rate of S. pneumoniae was 56% (957/1723). Pneumococcal carriage was associated with illness on the day of the interview (OR = 1.50, p = 0.04). The most common pneumococcal serotypes were in descending order 19F (16%), 23F (9%), 6A (8%), 29 (7%) and 6B (7%). One percent of the strains were non-typeable. The potential serotype coverage rate for PCV10 was 42% and 54% for PCV13.ConclusionAbout half of circulating pneumococcal serotypes in carriage in the Ugandan under-five population studied was covered by available PCVs.