Mechanism of Protection Induced by Group A Streptococcus Vaccine Candidate J8-DT: Contribution of B and T-Cells Towards Protection

Vaccination with J8-DT, a leading GAS vaccine candidate, results in protective immunity in mice. Analysis of immunologic correlates of protection indicated a role of J8-specific antibodies that were induced post-immunization. In the present study, several independent experimental approaches were employed to investigate the protective immunological mechanisms involved in J8-DT-mediated immunity. These approaches included the passive transfer of mouse or rabbit immune serum/antibodies in addition to selective depletion of T-cell subsets prior to bacterial challenge. Passive transfer of J8-DT antiserum/antibodies from mice and rabbits conferred significant resistance against challenge to mice. To exclude the possibility of involvement of other host immune factors, the studies were repeated in SCID mice, which highlighted the need for an ongoing immune response for long-lived protection. Depletion of CD4+ and CD8+ T-cell subsets confirmed that an active de novo immune response, involving CD4+ T-helper cells, is required for continued synthesis of antibodies resulting in protection against GAS infection. Taken together these results indicate an involvement of CD4+ T-cells in J8-DT-mediated protection possibly via an ability to maintain antibody levels. These results have considerable relevance to the development of a broad spectrum passive immunotherapy for GAS disease

Unintentional asphyxia, SIDS, and medically explained deaths:A descriptive study of outcomes of child death review (CDR) investigations following sudden unexpected death in infancy

Background: A comprehensive Child Death Review (CDR) program was introduced in England and Wales in 2008 but as yet data have only been analysed at a local level, limiting the learning from deaths. The aim of this study is to describe the profile of causes and risk factors for Sudden Unexpected Death in Infancy (SUDI) as determined by the new CDR program. Methods: This was a descriptive outcome study using data from Child Death Overview Panel (CDOP) Form C for SUDI cases dying during 2010-2 in the West Midlands region of England. The main outcome measures were: cause of death, risk factors and potential preventability of death, and determination of deaths probably due to unintentional asphyxia. Results: Data were obtained for 65/70 (93%) SUDI cases. 20/65 (31%) deaths were initially categorised as due to medical causes; 21/65 (32%) as SIDS, and 24/65 (37%) as undetermined. Reanalysis suggested that 2/21 SIDS and 7/24 undetermined deaths were probably due to unintentional asphyxia, with 6 of these involving co-sleeping and excessive parental alcohol consumption. Deaths classified as ‘undetermined’ had significantly higher total family and environmental risk factor scores (mean 2.6, 95% CI 2.0– 3.3) compared to those classified as SIDS (mean 1.6, 95% CI 1.2-1.9), or medical causes for death (mean 1.1, 95% CI 0.8-1.3). 9/20 (47%) of medical deaths, 19/21 (90%) SIDS and 23/24 (96%) undetermined deaths were considered to be potentially preventable. There were inadequacies in medical provision identified in 5/20 (25%) of medically explained deaths. Conclusions: The CDR program results in detailed information about risk factors for SUDI cases but failed to recognise deaths probably due to unintentional asphyxia. The misclassification of probable unintentional asphyxial deaths and SIDS as ‘undetermined deaths’ is likely to limit learning from these deaths and inhibit prevention strategies. Many SUDI occurred in families with mental illness, substance misuse and chaotic lifestyles and most in unsafe sleep-environments. This knowledge could be used to better target safe sleep advice for vulnerable families and prevent SUDI in the future

A systematic analysis of host factors reveals a Med23-interferon-λ regulatory axis against herpes simplex virus type 1 replication

Herpes simplex virus type 1 (HSV-1) is a neurotropic virus causing vesicular oral or genital skin lesions, meningitis and other diseases particularly harmful in immunocompromised individuals. To comprehensively investigate the complex interaction between HSV-1 and its host we combined two genome-scale screens for host factors (HFs) involved in virus replication. A yeast two-hybrid screen for protein interactions and a RNA interference (RNAi) screen with a druggable genome small interfering RNA (siRNA) library confirmed existing and identified novel HFs which functionally influence HSV-1 infection. Bioinformatic analyses found the 358 HFs were enriched for several pathways and multi-protein complexes. Of particular interest was the identification of Med23 as a strongly anti-viral component of the largely pro-viral Mediator complex, which links specific transcription factors to RNA polymerase II. The anti-viral effect of Med23 on HSV-1 replication was confirmed in gain-of-function gene overexpression experiments, and this inhibitory effect was specific to HSV-1, as a range of other viruses including Vaccinia virus and Semliki Forest virus were unaffected by Med23 depletion. We found Med23 significantly upregulated expression of the type III interferon family (IFN-λ) at the mRNA and protein level by directly interacting with the transcription factor IRF7. The synergistic effect of Med23 and IRF7 on IFN-λ induction suggests this is the major transcription factor for IFN-λ expression. Genotypic analysis of patients suffering recurrent orofacial HSV-1 outbreaks, previously shown to be deficient in IFN-λ secretion, found a significant correlation with a single nucleotide polymorphism in the IFN-λ3 (IL28b) promoter strongly linked to Hepatitis C disease and treatment outcome. This paper describes a link between Med23 and IFN-λ, provides evidence for the crucial role of IFN-λ in HSV-1 immune control, and highlights the power of integrative genome-scale approaches to identify HFs critical for disease progression and outcome

Reconstructing CNV genotypes using segregation analysis: combining pedigree information with CNV assay

<p>Abstract</p> <p>Background</p> <p>Repeated blocks of genome sequence have been shown to be associated with genetic diversity and disease risk in humans, and with phenotypic diversity in model organisms and domestic animals. Reliable tests are desirable to determine whether individuals are carriers of copy number variants associated with disease risk in humans and livestock, or associated with economically important traits in livestock. In some cases, copy number variants affect the phenotype through a dosage effect but in other cases, allele combinations have non-additive effects. In the latter cases, it has been difficult to develop tests because assays typically return an estimate of the sum of the copy number counts on the maternally and paternally inherited chromosome segments, and this sum does not uniquely determine the allele configuration. In this study, we show that there is an old solution to this new problem: segregation analysis, which has been used for many years to infer alleles in pedigreed populations.</p> <p>Methods</p> <p>Segregation analysis was used to estimate copy number alleles from assay data on simulated half-sib sheep populations. Copy number variation at the Agouti locus, known to be responsible for the recessive self-colour black phenotype, was used as a model for the simulation and an appropriate penetrance function was derived. The precision with which carriers and non-carriers of the undesirable single copy allele could be identified, was used to evaluate the method for various family sizes, assay strategies and assay accuracies.</p> <p>Results</p> <p>Using relationship data and segregation analysis, the probabilities of carrying the copy number alleles responsible for black or white fleece were estimated with much greater precision than by analyzing assay results for animals individually. The proportion of lambs correctly identified as non-carriers of the undesirable allele increased from 7% when the lambs were analysed alone to 80% when the lambs were analysed in half-sib families.</p> <p>Conclusions</p> <p>When a quantitative assay is used to estimate copy number alleles, segregation analysis of related individuals can greatly improve the precision of the estimates. Existing software for segregation analysis would require little if any change to accommodate the penetrance function for copy number assay data.</p

Evidence of Endemic Hendra Virus Infection in Flying-Foxes (Pteropus conspicillatus)—Implications for Disease Risk Management

This study investigated the seroepidemiology of Hendra virus in a spectacled flying-fox (Pteropus conspicillatus) population in northern Australia, near the location of an equine and associated human Hendra virus infection in late 2004. The pattern of infection in the population was investigated using a serial cross-sectional serological study over a 25-month period, with blood sampled from 521 individuals over six sampling sessions. Antibody titres to the virus were determined by virus neutralisation test. In contrast to the expected episodic infection pattern, we observed that seroprevalence gradually increased over the two years suggesting infection was endemic in the population over the study period. Our results suggested age, pregnancy and lactation were significant risk factors for a detectable neutralizing antibody response. Antibody titres were significantly higher in females than males, with the highest titres occurring in pregnant animals. Temporal variation in antibody titres suggests that herd immunity to the virus may wax and wane on a seasonal basis. These findings support an endemic infection pattern of henipaviruses in bat populations suggesting their infection dynamics may differ significantly from the acute, self limiting episodic pattern observed with related viruses (e.g. measles virus, phocine distemper virus, rinderpest virus) hence requiring a much smaller critical host population size to sustain the virus. These findings help inform predictive modelling of henipavirus infection in bat populations, and indicate that the life cycle of the reservoir species should be taken into account when developing risk management strategies for henipaviruses

Evidence of Endemic Hendra Virus Infection in Flying-Foxes (Pteropus conspicillatus)—Implications for Disease Risk Management

This study investigated the seroepidemiology of Hendra virus in a spectacled flying-fox (Pteropus conspicillatus) population in northern Australia, near the location of an equine and associated human Hendra virus infection in late 2004. The pattern of infection in the population was investigated using a serial cross-sectional serological study over a 25-month period, with blood sampled from 521 individuals over six sampling sessions. Antibody titres to the virus were determined by virus neutralisation test. In contrast to the expected episodic infection pattern, we observed that seroprevalence gradually increased over the two years suggesting infection was endemic in the population over the study period. Our results suggested age, pregnancy and lactation were significant risk factors for a detectable neutralizing antibody response. Antibody titres were significantly higher in females than males, with the highest titres occurring in pregnant animals. Temporal variation in antibody titres suggests that herd immunity to the virus may wax and wane on a seasonal basis. These findings support an endemic infection pattern of henipaviruses in bat populations suggesting their infection dynamics may differ significantly from the acute, self limiting episodic pattern observed with related viruses (e.g. measles virus, phocine distemper virus, rinderpest virus) hence requiring a much smaller critical host population size to sustain the virus. These findings help inform predictive modelling of henipavirus infection in bat populations, and indicate that the life cycle of the reservoir species should be taken into account when developing risk management strategies for henipaviruses

The mammals of Angola

Scientific investigations on the mammals of Angola started over 150 years ago, but information remains scarce and scattered, with only one recent published account. Here we provide a synthesis of the mammals of Angola based on a thorough survey of primary and grey literature, as well as recent unpublished records. We present a short history of mammal research, and provide brief information on each species known to occur in the country. Particular attention is given to endemic and near endemic species. We also provide a zoogeographic outline and information on the conservation of Angolan mammals. We found confirmed records for 291 native species, most of which from the orders Rodentia (85), Chiroptera (73), Carnivora (39), and Cetartiodactyla (33). There is a large number of endemic and near endemic species, most of which are rodents or bats. The large diversity of species is favoured by the wide range of habitats with contrasting environmental conditions, while endemism tends to be associated with unique physiographic settings such as the Angolan Escarpment. The mammal fauna of Angola includes 2 Critically Endangered, 2 Endangered, 11 Vulnerable, and 14 Near-Threatened species at the global scale. There are also 12 data deficient species, most of which are endemics or near endemics to the countryinfo:eu-repo/semantics/publishedVersio

Ecology and Transmission of Buruli Ulcer Disease: A Systematic Review

Buruli ulcer is a neglected emerging disease that has recently been reported in some countries as the second most frequent mycobacterial disease in humans after tuberculosis. Cases have been reported from at least 32 countries in Africa (mainly west), Australia, Southeast Asia, China, Central and South America, and the Western Pacific. Large lesions often result in scarring, contractual deformities, amputations, and disabilities, and in Africa, most cases of the disease occur in children between the ages of 4–15 years. This environmental mycobacterium, Mycobacterium ulcerans, is found in communities associated with rivers, swamps, wetlands, and human-linked changes in the aquatic environment, particularly those created as a result of environmental disturbance such as deforestation, dam construction, and agriculture. Buruli ulcer disease is often referred to as the “mysterious disease” because the mode of transmission remains unclear, although several hypotheses have been proposed. The above review reveals that various routes of transmission may occur, varying amongst epidemiological setting and geographic region, and that there may be some role for living agents as reservoirs and as vectors of M. ulcerans, in particular aquatic insects, adult mosquitoes or other biting arthropods. We discuss traditional and non-traditional methods for indicting the roles of living agents as biologically significant reservoirs and/or vectors of pathogens, and suggest an intellectual framework for establishing criteria for transmission. The application of these criteria to the transmission of M. ulcerans presents a significant challenge

Functional Redundancy of Two Pax-Like Proteins in Transcriptional Activation of Cyst Wall Protein Genes in Giardia lamblia

The protozoan Giardia lamblia differentiates from a pathogenic trophozoite into an infectious cyst to survive outside of the host. During encystation, genes encoding cyst wall proteins (CWPs) are coordinately induced. Pax family transcription factors are involved in a variety of developmental processes in animals. Nine Pax proteins have been found to play an important role in tissue and organ development in humans. To understand the progression from primitive to more complex eukaryotic cells, we tried to identify putative pax genes in the G. lamblia genome and found two genes, pax1 and pax2, with limited similarity. We found that Pax1 may transactivate the encystation-induced cwp genes and interact with AT-rich initiatior elements that are essential for promoter activity and transcription start site selection. In this study, we further characterized Pax2 and found that, like Pax1, Pax2 was present in Giardia nuclei and it may specifically bind to the AT-rich initiator elements of the encystation-induced cwp1-3 and myb2 genes. Interestingly, overexpression of Pax2 increased the cwp1-3 and myb2 gene expression and cyst formation. Deletion of the C-terminal paired domain or mutation of the basic amino acids of the paired domain resulted in a decrease of nuclear localization, DNA-binding activity, and transactivation activity of Pax2. These results are similar to those found in the previous Pax1 study. In addition, the profiles of gene expression in the Pax2 and Pax1 overexpressing cells significantly overlap in the same direction and ERK1 associated complexes may phosphorylate Pax2 and Pax1, suggesting that Pax2 and Pax1 may be downstream components of a MAPK/ERK1 signaling pathway. Our results reveal functional redundancy between Pax2 and Pax1 in up-regulation of the key encystation-induced genes. These results illustrate functional redundancy of a gene family can occur in order to increase maintenance of important gene function in the protozoan organism G. lamblia

Novel Structural Components of the Ventral Disc and Lateral Crest in Giardia intestinalis

Giardia intestinalis is a ubiquitous parasitic protist that is the causative agent of giardiasis, one of the most common protozoan diarrheal diseases in the world. Giardia trophozoites attach to the intestinal epithelium using a specialized and elaborate microtubule structure, the ventral disc. Surrounding the ventral disc is a less characterized putatively contractile structure, the lateral crest, which forms a continuous perimeter seal with the substrate. A better understanding of ventral disc and lateral crest structure, conformational dynamics, and biogenesis is critical for understanding the mechanism of giardial attachment to the host. To determine the components comprising the ventral disc and lateral crest, we used shotgun proteomics to identify proteins in a preparation of isolated ventral discs. Candidate disc-associated proteins, or DAPs, were GFP-tagged using a ligation-independent high-throughput cloning method. Based on disc localization, we identified eighteen novel DAPs, which more than doubles the number of known disc-associated proteins. Ten of the novel DAPs are associated with the lateral crest or outer edge of the disc, and are the first confirmed components of this structure. Using Fluorescence Recovery After Photobleaching (FRAP) with representative novel DAP::GFP strains we found that the newly identified DAPs tested did not recover after photobleaching and are therefore structural components of the ventral disc or lateral crest. Functional analyses of the novel DAPs will be central toward understanding the mechanism of ventral disc-mediated attachment and the mechanism of disc biogenesis during cell division. Since attachment of Giardia to the intestine via the ventral disc is essential for pathogenesis, it is possible that some proteins comprising the disc could be potential drug targets if their loss or disruption interfered with disc biogenesis or function, preventing attachment