A Highly Stable Prefusion Rsv F Vaccine Derived from Structural Analysis of the Fusion Mechanism

Respiratory syncytial virus (RSV) causes acute lower respiratory tract infections and is the leading cause of infant hospitalizations. Recently, a promising vaccine antigen based on the RSV fusion protein (RSV F) stabilized in the native prefusion conformation has been described. Here we report alternative strategies to arrest RSV F in the prefusion conformation based on the prevention of hinge movements in the first refolding region and the elimination of proteolytic exposure of the fusion peptide. A limited number of unique mutations are identified that stabilize the prefusion conformation of RSV F and dramatically increase expression levels. This highly stable prefusion RSV F elicits neutralizing antibodies in cotton rats and induces complete protection against viral challenge. Moreover, the structural and biochemical analysis of the prefusion variants suggests a function for p27, the excised segment that precedes the fusion peptide in the polypeptide chain

Regularization Methods for High-Dimensional Inference

High dimensionality is a common problem in statistical inference, and is becoming more prevalent in modern data analysis settings. While often data of interest may have a large -- often unmanageable -- dimension, modifications to various well-known techniques can be made to improve performance and aid interpretation. We typically assume that although predictors lie in a high-dimensional ambient space, they have a lower-dimensional structure that can be exploited through either prior knowledge or estimation. In performing regression, the structure in the predictors can be taken into account implicitly through regularization. In the case where the underlying structure in the predictors is known, using knowledge of this structure can yield improvements in prediction. We approach this problem through regularization using a known projection based on knowledge of the structure of the Grassmannian. Using this projection, we can obtain improvements over many classical and recent techniques in both regression and classification problems with only minor modification to a typical least squares problem. The structure of the predictors can also be taken into account explicitly through methods of dimension reduction. We often wish to have a lower-dimensional representation of our data in order to build potentially more interpretable models or to explore possible connections between predictors. In many problems, we are faced with data that does not have a similar distribution between estimating the model parameters and performing prediction. This results in problems when estimating a lower-dimensional structure of the predictors, as it may change. We pose methods for estimating a linear dimension reduction that will take into account these discrepancies between data distributions, while also incorporating as much of the information as possible in the data into construction of the predictor structure. These methods are built on regularized maximum likelihood and yield improvements in many cases of regression and classification, including those cases in which predictor dimension changes between training and testing

Recombinant low-seroprevalent adenoviral vectors Ad26 and Ad35 expressing the respiratory syncytial virus (RSV) fusion protein induce protective immunity against RSV infection in cotton rats

AbstractRSV is an important cause of lower respiratory tract infections in children, the elderly and in those with underlying medical conditions. Although the high disease burden indicates an urgent need for a vaccine against RSV, no licensed RSV vaccine is currently available. We developed an RSV vaccine candidate based on the low-seroprevalent human adenovirus serotypes 26 and 35 (Ad26 and Ad35) encoding the RSV fusion (F) gene. Single immunization of mice with either one of these vectors induced high titers of RSV neutralizing antibodies and high levels of F specific interferon-gamma-producing T cells. A Th1-type immune response was indicated by a high IgG2a/IgG1 ratio of RSV-specific antibodies, strong induction of RSV-specific interferon-gamma and tumor necrosis factor-alpha cytokine producing CD8 Tcells, and low RSV-specific CD4 T-cell induction. Both humoral and cellular responses were increased upon a boost with RSV-F expressing heterologous adenovirus vector (Ad35 boost after Ad26 prime or vice versa). Both single immunization and prime-boost immunization of cotton rats induced high and long-lasting RSV neutralizing antibody titers and protective immunity against lung and nasal RSV A2 virus load up to at least 30 weeks after immunization. Cotton rats were also completely protected against challenge with a RSV B strain (B15/97) after heterologous prime-boost immunization. Lungs from vaccinated animals showed minimal damage or inflammatory infiltrates post-challenge, in contrast to animals vaccinated with formalin-inactivated virus. Our results suggest that recombinant human adenoviral Ad26 and Ad35 vectors encoding the RSV F gene have the potential to provide broad and durable protection against RSV in humans, and appear safe to be investigated in infants

Establishment and characterization of an infectious cDNA clone of a classical swine fever virus LOM strain

Classical swine fever virus (CSFV) causes a highly contagious disease among swine that has an important economic impact worldwide. CSFV strain LOM is an attenuated virus of low virulent strain of Miyagi isolated from Japan in 1956. Eight DNA fragments representing the genome of the CSFV strain LOM were obtained by RT-PCR. These were used to determine the complete nucleotide sequence and construct a full-length cDNA clone which was called Flc-LOM. Sequence analysis of the recombinant clone (Flc-LOM) revealed the presence of eight mutations, resulting in two amino acid substitutions, when compared to the parental sequence. RNA transcripts of both LOM and Flc-LOM were directly infectious in PK-15 cells. The rescued Flc-LOM virus grew more slowly than the parental virus, LOM, in the cells. Intramuscular immunization with Flc-LOM was safe and highly immunogenic in pigs; no clinical signs or virus transmission to sentinel animals were observed after 35 days. CSFV-specific neutralizing antibodies were detected 14 days post-infection. After challenge with the virulent CSFV strain SW03, pigs immunized with Flc-LOM were shown to be fully protected. Thus, our newly established infectious clone of CSFV, Flc-LOM, could serve as a vaccine candidate

A highly attenuated recombinant human respiratory syncytial virus lacking the G protein induces long-lasting protection in cotton rats

<p>Abstract</p> <p>Background</p> <p>Respiratory syncytial virus (RSV) is a primary cause of serious lower respiratory tract illness for which there is still no safe and effective vaccine available. Using reverse genetics, recombinant (r)RSV and an rRSV lacking the G gene (ΔG) were constructed based on a clinical RSV isolate (strain 98-25147-X).</p> <p>Results</p> <p>Growth of both recombinant viruses was equivalent to that of wild type virus in Vero cells, but was reduced in human epithelial cells like Hep-2. Replication in cotton rat lungs could not be detected for ΔG, while rRSV was 100-fold attenuated compared to wild type virus. Upon single dose intranasal administration in cotton rats, both recombinant viruses developed high levels of neutralizing antibodies and conferred comparable long-lasting protection against RSV challenge; protection against replication in the lungs lasted at least 147 days and protection against pulmonary inflammation lasted at least 75 days.</p> <p>Conclusion</p> <p>Collectively, the data indicate that a single dose immunization with the highly attenuated ΔG as well as the attenuated rRSV conferred long term protection in the cotton rat against subsequent RSV challenge, without inducing vaccine enhanced pathology. Since ΔG is not likely to revert to a less attenuated phenotype, we plan to evaluate this deletion mutant further and to investigate its potential as a vaccine candidate against RSV infection.</p

Systemic Signature of the Lung Response to Respiratory Syncytial Virus Infection

Respiratory Syncytial Virus is a frequent cause of severe bronchiolitis in children. To improve our understanding of systemic host responses to RSV, we compared BALB/c mouse gene expression responses at day 1, 2, and 5 during primary RSV infection in lung, bronchial lymph nodes, and blood. We identified a set of 53 interferon-associated and innate immunity genes that give correlated responses in all three murine tissues. Additionally, we identified blood gene signatures that are indicative of acute infection, secondary immune response, and vaccine-enhanced disease, respectively. Eosinophil-associated ribonucleases were characteristic for the vaccine-enhanced disease blood signature. These results indicate that it may be possible to distinguish protective and unfavorable patient lung responses via blood diagnostics

Ultra-Fast and Sensitive Detection of Non-Typhoidal Salmonella Using Microwave-Accelerated Metal-Enhanced Fluorescence (“MAMEF”)

Certain serovars of Salmonella enterica subsp. enterica cause invasive disease (e.g., enteric fever, bacteremia, septicemia, meningitis, etc.) in humans and constitute a global public health problem. A rapid, sensitive diagnostic test is needed to allow prompt initiation of therapy in individual patients and for measuring disease burden at the population level. An innovative and promising new rapid diagnostic technique is microwave-accelerated metal-enhanced fluorescence (MAMEF). We have adapted this assay platform to detect the chromosomal oriC locus common to all Salmonella enterica subsp. enterica serovars. We have shown efficient lysis of biologically relevant concentrations of Salmonella spp. suspended in bacteriological media using microwave-induced lysis. Following lysis and DNA release, as little as 1 CFU of Salmonella in 1 ml of medium can be detected in <30 seconds. Furthermore the assay is sensitive and specific: it can detect oriC from Salmonella serovars Typhi, Paratyphi A, Paratyphi B, Paratyphi C, Typhimurium, Enteritidis and Choleraesuis but does not detect Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Streptococcus pneumoniae, Haemophilus influenzae or Acinetobacter baumanii. We have also performed preliminary experiments using a synthetic Salmonella oriC oligonucleotide suspended in whole human blood and observed rapid detection when the sample was diluted 1∶1 with PBS. These pre-clinical data encourage progress to the next step to detect Salmonella in blood (and other ordinarily sterile, clinically relevant body fluids)

Living Bacterial Sacrificial Porogens to Engineer Decellularized Porous Scaffolds

Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types

Update on current views and advances on RSV infection (Review).

Respiratory syncytial virus (RSV) infection represents an excellent paradigm of precision medicine in modern paediatrics and several clinical trials are currently performed in the prevention and management of RSV infection. A new taxonomic terminology for RSV was recently adopted, while the diagnostic and omics techniques have revealed new modalities in the early identification of RSV infections and for better understanding of the disease pathogenesis. Coordinated clinical and research efforts constitute an important step in limiting RSV global predominance, improving epidemiological surveillance, and advancing neonatal and paediatric care. This review article presents the key messages of the plenary lectures, oral presentations and posters of the '5th workshop on paediatric virology' (Sparta, Greece, 12th October 2019) organized by the Paediatric Virology Study Group, focusing on recent advances in the epidemiology, pathogenesis, diagnosis, prognosis, clinical management and prevention of RSV infection in childhood

Methodological approaches for studying the microbial ecology of drinking water distribution systems

The study of the microbial ecology of drinking water distribution systems (DWDS) has traditionally been based on culturing organisms from bulk water samples. The development and application of molecular methods has supplied new tools for examining the microbial diversity and activity of environmental samples, yielding new insights into the microbial community and its diversity within these engineered ecosystems. In this review, the currently available methods and emerging approaches for characterising microbial communities, including both planktonic and biofilm ways of life, are critically evaluated. The study of biofilms is considered particularly important as it plays a critical role in the processes and interactions occurring at the pipe wall and bulk water interface. The advantages, limitations and usefulness of methods that can be used to detect and assess microbial abundance, community composition and function are discussed in a DWDS context. This review will assist hydraulic engineers and microbial ecologists in choosing the most appropriate tools to assess drinking water microbiology and related aspects