[Modeling T2 high severe asthma using human induced pluripotent stem cells (hiPSC)]

Severe asthma patients with persistent airflow obstruction are characterized by functional obstruction due to mucus plugs containing mucins, fibrin, and eosinophil derived Charcot- Leyden crystals. The molecular mechanisms underlying this endotype are not clearly understood. Developing new models is crucial to respiratory research insofar as critical differences exist between human and rodent airway epithelium. We (and other teams) have shown that it is possible to reconstitute in vitro a complex and functional airway epithelium displaying all the features described in vivo from human-induced pluripotent stem cells (hiPSC). Our aim is to establish a human in vitro model of severe asthma that will recapitulate airway epithelium remodeling and mucus plugs.

Concomitant NA and NS deletion on avian Influenza H3N1 virus associated with hen mortality in France in 2019

An H3N1 avian influenza virus was detected in a laying hens farm in May 2019 which had experienced 25% mortality in Northern France. The complete sequencing of this virus showed that all segment sequences belonged to the Eurasian lineage and were phylogenetically very close to many of the Belgian H3N1 viruses detected in 2019. The French virus presented two genetic particularities with NA and NS deletions that could be related to virus adaptation from wild to domestic birds and could increase virulence, respectively. Molecular data of H3N1 viruses suggest that these two deletions occurred at two different times.

Co-circulation of genetically distinct highly pathogenic avian influenza A clade 2.3.4.4 (H5N6) viruses in wild waterfowl and poultry in Europe and East Asia, 2017-18

Highly pathogenic avian influenza (HPAI) H5 clade 2.3.4.4 viruses were first introduced into Europe in late 2014 and re-introduced in late 2016, following detections in Asia and Russia. In contrast to the 2014–15 H5N8 wave, there was substantial local virus amplification in wild birds in Europe in 2016–17 and associated wild bird mortality, with evidence for occasional gene exchange with low pathogenic avian influenza (LPAI) viruses. Since December 2017, several European countries have again reported events or outbreaks with HPAI H5N6 reassortant viruses in both wild birds and poultry, respectively. Previous phylogenetic studies have shown that the two earliest incursions of HPAI H5N8 viruses originated in Southeast Asia and subsequently spread to Europe. In contrast, this study indicates that recent HPAI H5N6 viruses evolved from the H5N8 2016–17 viruses during 2017 by reassortment of a European HPAI H5N8 virus and wild host reservoir LPAI viruses. The genetic and phenotypic differences between these outbreaks and the continuing detections of HPAI viruses in Europe are a cause of concern for both animal and human health. The current co-circulation of potentially zoonotic HPAI and LPAI virus strains in Asia warrants the determination of drivers responsible for the global spread of Asian lineage viruses and the potential threat they pose to public health.

Enlargement of the WHO international repository for platelet transfusion-relevant bacteria reference strains

BACKGROUND AND OBJECTIVES

Interventions to prevent and detect bacterial contamination of platelet concentrates (PCs) have reduced, but not eliminated the sepsis risk. Standardized bacterial strains are needed to validate detection and pathogen reduction technologies in PCs. Following the establishment of the First International Reference Repository of Platelet Transfusion-Relevant Bacterial Reference Strains (the 'repository'), the World Health Organization (WHO) Expert Committee on Biological Standardisation (ECBS) endorsed further repository expansion.

MATERIALS AND METHODS

Sixteen bacterial strains, including the four repository strains, were distributed from the Paul-Ehrlich-Institut (PEI) to 14 laboratories in 10 countries for enumeration, identification and growth measurement on days 2, 4 and 7 after low spiking levels [10-25 colony-forming units (CFU)/PC bag]. Spore-forming (Bacillus cereusPEI-B-P-07-S, Bacillus thuringiensisPEI-B-P-57-S), Gram-negative (Enterobacter cloacaePEI-B-P-43, Morganella morganiiPEI-B-P-74, PEI-B-P-91, Proteus mirabilisPEI-B-P-55, Pseudomonas fluorescensPEI-B-P-77, Salmonella choleraesuisPEI-B-P-78, Serratia marcescensPEI-B-P-56) and Gram-positive (Staphylococcus aureusPEI-B-P-63, Streptococcus dysgalactiaePEI-B-P-71, Streptococcus bovisPEI-B-P-61) strains were evaluated.

RESULTS

Bacterial viability was conserved after transport to the participating laboratories with one exception (M. morganiiPEI-B-P-74). All other strains showed moderate-to-excellent growth. Bacillus cereus, B. thuringiensis, E. coli, K. pneumoniae, P. fluorescens, S. marcescens, S. aureus and S. dysgalactiae grew to >10⁶ CFU/ml by day 2. Enterobacter cloacae, P. mirabilis, S. epidermidis, S. bovis and S. pyogenes achieved >10⁶ CFU/ml at day 4. Growth of S. choleraesuis was lower and highly variable.

CONCLUSION

The WHO ECBS approved all bacterial strains (except M. morganiiPEI-B-P-74 and S. choleraesuisPEI-B-P-78) for repository enlargement. The strains were stable, suitable for spiking with low CFU numbers, and proliferation was independent of the PC donor.

Protection Afforded by a Recombinant Turkey Herpesvirus-H5 Vaccine Against the 2014 European Highly Pathogenic H5N8 Avian Influenza Strain

A highly pathogenic avian influenza (HPAI) H5N8 (clade 2.3.4.4) virus, circulating in Asia (South Korea, Japan, and southern China) since the beginning of 2014, reached the European continent in November 2014. Germany, the Netherlands, the United Kingdom, Italy, and Hungary confirmed H5N8 infection of poultry farms of different species and of several wild bird species. Unlike the Asian highly pathogenic (HP) H5N1, this HP H5N8 also went transatlantic and reached the American West Coast by the end of 2014, affecting wild birds as well as backyard and commercial poultry. This strain induces high mortality and morbidity in Galliformes, whereas wild birds seem only moderately affected. A recombinant turkey herpesvirus (rHVT) vector vaccine expressing the H5 gene of a clade 2.2 H5N1 strain (rHVT-H5) previously demonstrated a highly efficient clinical protection and reduced viral excretion against challenge with Asian HP H5N1 strains of various clades (2.2, 2.2.1, 2.2.1.1, 2.1.3, 2.1.3.2, and 2.3.2.1) and was made commercially available in various countries where the disease is endemic. To evaluate the protective efficacy of the rHVT-H5 vaccine against the first German H5N8 turkey isolate (H5N8 GE), a challenge experiment was set up in specific-pathogen-free (SPF) chickens, and the clinical and excretional protection was evaluated. SPF chickens were vaccinated subcutaneously at 1 day old and challenged oculonasally at 4 wk of age with two viral dosages, 10(5) and 10(6) 50% egg infective doses. Morbidity and mortality were monitored daily in unvaccinated and vaccinated groups, whereas viral shedding by oropharyngeal and cloacal routes was evaluated at 2, 5, 9, and 14 days postinoculation (dpi). Serologic monitoring after vaccination and challenge was also carried out. Despite its high antigenic divergence of the challenge H5N8 strain, a single rHVT-H5 vaccine administration at 1 day old resulted in a full clinical protection against challenge and a significant reduction of viral shedding in the vaccinated birds.

Specific antibody-mediated immunity in the reproductive tract of laying chickens immunized against Newcastle disease with conventional attenuated and inactivated vaccines

Despite the widespread and successful use of Newcastle disease (ND) vaccines, Newcastle disease virus (NDV) can seriously injure the reproductive tract of egg-laying hens, leading to rapid egg-drop and poor shell quality. Few published studies investigated local NDV-specific immune response in the reproductive tract after ND vaccination of hens. The present study investigated, for the first time, local NDV-specific antibody-mediated immunity in segments of the oviduct during the laying period. Specific pathogen-free (SPF) White Leghorn chickens were immunized following an ND vaccination programme applied in the field, which combined ND-attenuated vaccine (inoculated subcutaneously at one day, 2 weeks and 11 weeks of age) with inactivated vaccine (inoculated intramuscularly at 17 weeks). The infundibulum, magnum, isthmus and uterus (segments of the reproductive tract) were harvested at 28 weeks and 32 weeks of age (during the laying period). Supernatant from ex vivo tissue culture was collected and tested by: (i) haemagglutination inhibition (HI) test, (ii) commercial IDVet ND-enzyme-linked immunosorbent assay (ELISA) and (iii) NDV-specific IgG, IgM and IgA in-house ELISAs. For all sampling time points and oviduct segments, all samples were positive for commercial ND-ELISA and in-house ELISA-IgG. However, six of these ELISA-IgG positive samples yielded negative results when submitted to the HI test. Interestingly, NDV-specific IgM and IgA were detected frequently in the infundibulum and magnum as compared to the isthmus and uterus. These results show that the antibody immune response in the oviduct was induced by the timing of attenuated and inactivated ND vaccinations.

ARIA 2016: Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma and rhinitis and (3) to develop guidelines with all stakeholders that could be used globally for all countries and populations. ARIA—disseminated and implemented in over 70 countries globally—is now focusing on the implementation of emerging technologies for individualized and predictive medicine. MASK [MACVIA (Contre les Maladies Chroniques pour un Vieillissement Actif)-ARIA Sentinel NetworK] uses mobile technology to develop care pathways for the management of rhinitis and asthma by a multi-disciplinary group and by patients themselves. An app (Android and iOS) is available in 20 countries and 15 languages. It uses a visual analogue scale to assess symptom control and work productivity as well as a clinical decision support system. It is associated with an inter-operable tablet for physicians and other health care professionals. The scaling up strategy uses the recommendations of the European Innovation Partnership on Active and Healthy Ageing. The aim of the novel ARIA approach is to provide an active and healthy life to rhinitis sufferers, whatever their age, sex or socio-economic status, in order to reduce health and social inequalities incurred by the disease.

Scaling up strategies of the chronic respiratory disease programme of the European Innovation Partnership on Active and Healthy Ageing (Action Plan B3: Area 5)

Action Plan B3 of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA) focuses on the integrated care of chronic diseases. Area 5 (Care Pathways) was initiated using chronic respiratory diseases as a model. The chronic respiratory disease action plan includes (1) AIRWAYS integrated care pathways (ICPs), (2) the joint initiative between the Reference site MACVIA-LR (Contre les MAladies Chroniques pour un VIeillissement Actif) and ARIA (Allergic Rhinitis and its Impact on Asthma), (3) Commitments for Action to the European Innovation Partnership on Active and Healthy Ageing and the AIRWAYS ICPs network. It is deployed in collaboration with the World Health Organization Global Alliance against Chronic Respiratory Diseases (GARD). The European Innovation Partnership on Active and Healthy Ageing has proposed a 5-step framework for developing an individual scaling up strategy: (1) what to scale up: (1-a) databases of good practices, (1-b) assessment of viability of the scaling up of good practices, (1-c) classification of good practices for local replication and (2) how to scale up: (2-a) facilitating partnerships for scaling up, (2-b) implementation of key success factors and lessons learnt, including emerging technologies for individualised and predictive medicine. This strategy has already been applied to the chronic respiratory disease action plan of the European Innovation Partnership on Active and Healthy Ageing.

Neutralizing TNFα restores glucocorticoid sensitivity in a mouse model of neutrophilic airway inflammation

Asthma is a heterogeneous disorder, evidenced by distinct types of inflammation resulting in different responsiveness to therapy with glucocorticoids (GCs). Tumor necrosis factor α (TNFα) is involved in asthma pathogenesis, but anti-TNFα therapies have not proven broadly effective. The effects of anti-TNFα treatment on steroid resistance have never been assessed. We investigated the role of TNFα blockade using etanercept in the responsiveness to GCs in two ovalbumin-based mouse models of airway hyperinflammation. The first model is GC sensitive and T helper type 2 (Th2)/eosinophil driven, whereas the second reflects GC-insensitive, Th1/neutrophil-predominant asthma subphenotypes. We found that TNFα blockade restores the therapeutic effects of GCs in the GC-insensitive model. An adoptive transfer indicated that the TNFα-induced GC insensitivity occurs in the non-myeloid compartment. Early during airway hyperinflammation, mice are GC insensitive specifically at the level of thymic stromal lymphopoietin (Tslp) transcriptional repression, and this insensitivity is reverted when TNFα is neutralized. Interestingly, TSLP knockout mice displayed increased inflammation in the GC-insensitive model, suggesting a limited therapeutic application of TSLP-neutralizing antibodies in subsets of patients suffering from Th2-mediated asthma. In conclusion, we demonstrate that TNFα reduces the responsiveness to GCs in a mouse model of neutrophilic airway inflammation. Thus antagonizing TNFα may offer a new strategy for therapeutic intervention in GC-resistant asthma.

Evaluation of the pathogenicity of West Nile virus (WNV) lineage 2 strains in a SPF chicken model of infection: NS3-249Pro mutation is neither sufficient nor necessary for conferring virulence

Lineage 2 West Nile virus (WNV) strains were reported for the first time in Europe in 2004. Despite an almost silent circulation around their entry point in Hungary, an upsurge of pathogenicity occurred in 2010 as 262 people suffered from neuroinvasive disease in Greece. This increase in virulence was imputed to the emergence of a His249Pro mutation in the viral NS3 helicase, as previously evidenced in American crows experimentally infected with the prototype lineage 1 North-American WNV strain. However, since 2003, WNV strains bearing the NS3Pro genotype are regularly isolated in Western-Mediterranean countries without being correlated to any virulent outbreak in vertebrates. We thus sought to evaluate the weight of the NS3_249Pro genotype as a virulence marker of WNV in an in vivo avian model of WNV infection. We therefore characterized three genetically-related Eastern-Europe lineage 2 WNV strains in day-old specific pathogen-free (SPF) chickens: Hun2004 and Aus2008 which are both characterized by a NS3_249His genotype, and Gr2011 which is characterized by a NS3_249Pro genotype. Unlike Hun2004 and Aus2008, Gr2011 was weakly virulent in SPF chicks as Gr2011-induced viremia was lower and waned quicklier than in the Hun2004 and Aus2008 groups. Overall, this study showed that the presence of a proline residue at position 249 of the viral NS3 helicase is neither sufficient nor necessary to confer pathogenicity to any given lineage 2 WNV strain in birds.

Regulatory T-cell development and function are impaired in mice lacking membrane expression of full length intercellular adhesion molecule-1

To further investigate the contribution of intercellular adhesion molecule-1 (ICAM-1) to adaptive immune responses, we analysed T-cell development and function in mice lacking full-length ICAM-1 (ICAM-1(tm1Jcgr) ). Compared with wild-type (ICAM-1(WT) ) mice, ICAM-1(tm1Jcgr) mice have impaired thymocyte development. Proportions and numbers of double negative, double positive, mature CD4(+) and CD8(+) thymocytes, as well as of regulatory T (Treg) cells were also significantly decreased. In the periphery, ICAM-1(tm1Jcgr) mice had significantly decreased proportions and numbers of naive and activated/memory CD4(+) and CD8(+) T cells, as well as of Treg cells, in lymph nodes but not in the spleen. In vitro activation of CD4(+) and CD8(+) T cells from ICAM-1(tm1Jcgr) mice with anti-CD3 antibodies and antigen-presenting cells (APCs) resulted in a significantly weaker proliferation, whereas proliferation induced with anti-CD3 and anti-CD28 antibody-coated beads was normal. In vivo immunization of ICAM-1(tm1Jcgr) mice resulted in normal generation of specific effector and memory immune responses that protect against a viral challenge. However, contrary to ICAM-1(WT) mice, immunization-induced specific effectors could not eradicate immunogen-expressing tumours. Treg cells from ICAM-1(tm1Jcgr) mice have abnormal activation and proliferation induced by anti-CD3 antibody and APCs, and have markedly decreased suppressive activity in vitro. In contrast to ICAM-1(WT) mice, they were unable to control experimentally induced colitis in vivo. Hence, our results further highlight the pleiotropic role of ICAM-1 in T-cell-dependent immune responses, with a major role in Treg cell development and suppressive function.

MACVIA-ARIA Sentinel NetworK for allergic rhinitis (MASK-rhinitis): the new generation guideline implementation

Several unmet needs have been identified in allergic rhinitis: identification of the time of onset of the pollen season, optimal control of rhinitis and comorbidities, patient stratification, multidisciplinary team for integrated care pathways, innovation in clinical trials and, above all, patient empowerment. MASK-rhinitis (MACVIA-ARIA Sentinel NetworK for allergic rhinitis) is a simple system centred around the patient which was devised to fill many of these gaps using Information and Communications Technology (ICT) tools and a clinical decision support system (CDSS) based on the most widely used guideline in allergic rhinitis and its asthma comorbidity (ARIA 2015 revision). It is one of the implementation systems of Action Plan B3 of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA). Three tools are used for the electronic monitoring of allergic diseases: a cell phone-based daily visual analogue scale (VAS) assessment of disease control, CARAT (Control of Allergic Rhinitis and Asthma Test) and e-Allergy screening (premedical system of early diagnosis of allergy and asthma based on online tools). These tools are combined with a clinical decision support system (CDSS) and are available in many languages. An e-CRF and an e-learning tool complete MASK. MASK is flexible and other tools can be added. It appears to be an advanced, global and integrated ICT answer for many unmet needs in allergic diseases which will improve policies and standards.

Are allergic multimorbidities and IgE polysensitization associated with the persistence or re-occurrence of foetal type 2 signalling? The MeDALL hypothesis

Allergic diseases [asthma, rhinitis and atopic dermatitis (AD)] are complex. They are associated with allergen-specific IgE and nonallergic mechanisms that may coexist in the same patient. In addition, these diseases tend to cluster and patients present concomitant or consecutive diseases (multimorbidity). IgE sensitization should be considered as a quantitative trait. Important clinical and immunological differences exist between mono- and polysensitized subjects. Multimorbidities of allergic diseases share common causal mechanisms that are only partly IgE-mediated. Persistence of allergic diseases over time is associated with multimorbidity and/or IgE polysensitization. The importance of the family history of allergy may decrease with age. This review puts forward the hypothesis that allergic multimorbidities and IgE polysensitization are associated and related to the persistence or re-occurrence of foetal type 2 signalling. Asthma, rhinitis and AD are manifestations of a common systemic immune imbalance (mesodermal origin) with specific patterns of remodelling (ectodermal or endodermal origin). This study proposes a new classification of IgE-mediated allergic diseases that allows the definition of novel phenotypes to (i) better understand genetic and epigenetic mechanisms, (ii) better stratify allergic preschool children for prognosis and (iii) propose novel strategies of treatment and prevention.

Next-generation sequencing shows West Nile virus quasispecies diversification after a single passage in a carrion crow (Corvus corone) in vivo infection model

West Nile virus (WNV) occurs as a population of genetic variants (quasispecies) infecting a single animal. Previous low-resolution viral genetic diversity estimates in sampled wild birds and mosquitoes, and in multiple-passage adaptation studies in vivo or in cell culture, suggest that WNV genetic diversification is mostly limited to the mosquito vector. This study investigated genetic diversification of WNV in avian hosts during a single passage using next-generation sequencing. Wild-captured carrion crows were subcutaneously infected using a clonal Middle-East WNV. Blood samples were collected 2 and 4 days post-infection. A reverse-transcription (RT)-PCR approach was used to amplify the WNV genome directly from serum samples prior to next-generation sequencing resulting in an average depth of at least 700 ×  in each sample. Appropriate controls were sequenced to discriminate biologically relevant low-frequency variants from experimentally introduced errors. The WNV populations in the wild crows showed significant diversification away from the inoculum virus quasispecies structure. By contrast, WNV populations in intracerebrally infected day-old chickens did not diversify from that of the inoculum. Where previous studies concluded that WNV genetic diversification is only experimentally demonstrated in its permissive insect vector species, we have experimentally shown significant diversification of WNV populations in a wild bird reservoir species.

Quantification of rHVT-F genome load in feather follicles by specific real-time qPCR as an indicator of NDV-specific humoral immunity induced by day-old vaccination in SPF chickens

The purpose of this study was to look for a reliable molecular method for confirmation of uptake of recombinant turkey herpesvirus vaccine against Newcastle disease (rHVT-F) and for use as a valuable prediction tool of Newcastle disease virus (NDV)-specific immune response in chickens deprived of maternally derived antibody (MDA). A quantitative real-time polymerase chain reaction (real-time qPCR) specific to rHVT-F was developed. The method was applied to various tissue samples taken from specific pathogen free (SPF) chickens experimentally inoculated at day-old with one dose of rHVT-F vaccine over a 6-week period. Among the tested tissues, the rHVT-F vaccine was detected predominantly in the bursa of Fabricius (BF) and the lung for the first week, followed by a progressive decline from 9 days onwards. Then, an increase of genome load was observed in the feather follicles (FF) with a peak at 2 weeks, rising to a level almost 10(3)-fold greater than in the other tissues. Importantly, the rHVT-F genome load in FF appeared to be strongly correlated to the humoral immunity specific to NDV as evaluated by haemagglutination inhibition (HI) test and NDV-specific IgG, IgM and IgA ELISAs. This is the first report of quantification of rHVT-F vaccine in FF and its correlation with the induction of ND-specific immune response in chickens with no MDA. Our data indicate that the application of this real-time qPCR assay on FF samples taken from chickens in the field may be used to confirm rHVT-F vaccine administration and uptake with the important added benefit of offering a non-disruptive sampling procedure.

Flow cytometric sexing of spider sperm reveals an equal sperm production ratio in a female-biased species

Producing equal amounts of male and female offspring has long been considered an evolutionarily stable strategy. Nevertheless, exceptions to this general rule (i.e. male and female biases) are documented in many taxa, making sex allocation an important domain in current evolutionary biology research. Pinpointing the underlying mechanism of sex ratio bias is challenging owing to the multitude of potential sex ratio-biasing factors. In the dwarf spider, Oedothorax gibbosus, infection with the bacterial endosymbiont Wolbachia results in a female bias. However, pedigree analysis reveals that other factors influence sex ratio variation. In this paper, we investigate whether this additional variation can be explained by the unequal production of male- and female-determining sperm cells during sperm production. Using flow cytometry, we show that males produce equal amounts of male- and female-determining sperm cells; thus bias in sperm production does not contribute to the sex ratio bias observed in this species. This demonstrates that other factors such as parental genes suppressing endosymbiont effects and cryptic female choice might play a role in sex allocation in this species.

Self-adjuvanting influenza candidate vaccine presenting epitopes for cell-mediated immunity on a proteinaceous multivalent nanoplatform

We exploit the features of a virus-like particle, adenoviral dodecahedron (Ad Dd), for engineering a multivalent vaccination platform carrying influenza epitopes for cell-mediated immunity. The delivery platform, Ad Dd, is a proteinaceous, polyvalent, and biodegradable nanoparticle endowed with remarkable endocytosis activity that can be engineered to carry 60 copies of a peptide. Influenza M1 is the most abundant influenza internal protein with the conserved primary structure. Two different M1 immunodominant epitopes were separately inserted in Dd external positions without destroying the particles' dodecahedric structure. Both kinds of DdFluM1 obtained through expression in baculovirus system were properly presented by human dendritic cells triggering efficient activation of antigen-specific T cells responses. Importantly, the candidate vaccine was able to induce cellular immunity in vivo in chickens. These results warrant further investigation of Dd as a platform for candidate vaccine, able to stimulate cellular immune responses.

Chasing notifiable avian influenza in domestic poultry: a case report of low-pathogenic avian influenza h5 viruses in two Belgian holdings

In December 2008, bird species in two geographically distant holdings were found positive for H5 viruses following the annual Avian influenza serological screening in Belgium. The virological tests performed identified in one holding a low-pathogenic avian influenza (LPAI) virus subtype H5N2, and a H5 LPAI virus was identified by real-time PCR and direct sequencing at the second holding. The first farm was an outdoor mixed holding housing ornamental birds and poultry (n = 6000) and the second a free-range geese breeding farm (n = 1500). No clinical signs or mortalities were reported. Control measures defined by Council Directive 2005/94/EC were followed, including notification to the European Commission via the Animal Disease Notification System and to the World Organization for Animal Health, and poultry were killed, while ornamental bird species were quarantined. Partial sequencing of the H5N2 virus haemagglutinin and neuraminidase N2 gene sequences revealed a close homology to some recent LPAI isolates identified from wild birds in Germany and Italy and from wild birds in Eurasia and Africa, respectively. It is noteworthy that, these two holdings were already H5 positive based on HI test results carried out during the previous serological screening; however, no virus was detected at that time. To have a better understanding of the potential 'silent' circulation of the H5N2 isolate in the field, experimental infections of chickens and turkeys were performed. The low excretion detected might in part explain viral persistence not associated with spread between gallinaceous birds in the same holding, indicating that the H5N2 LPAI isolate was not fully adapted to these two poultry species. Our results highlighted limitations to only using serological screening for the early detection of LPAI in an 'at-risk farm', suggesting that virological and serological monitoring tests be applied simultaneously as a means of testing animals in 'at-risk farms'.

Molecular epidemiological analysis of the transboundary transmission of 2003 highly pathogenic avian influenza H7N7 outbreaks between the Netherlands and Belgium

The 2003 outbreak of Highly pathogenic avian influenza (HPAI) A(H7N7) in the Netherlands, Belgium and Germany resulted in significant genetic diversification that proved informative for tracing transmission events. Building on previous investigations on the Dutch outbreak, we focused on the potential transnational transmissions between the Netherlands and Belgium. Although no clear epidemiological links could be identified from the tracing data, the transmission network based on concatenated HA-NA-PB2 sequences supports at least three independent introductions from the Netherlands to Belgium and suggests one possible introduction form Belgium back to the Netherlands. Two introductions in the Belgian province of Limburg occurred from nearby farms in the Dutch province of Limburg. One introduction resulted in three secondary infected farms, while a second introduction did not cause secondary infections. The third introduction into Belgium occurred in the north of the Antwerp province, very close to the national border, and originated from the North of the Dutch province Brabant (long distance transmission, >65 km). The virus spread to two additional Belgian farms, one of which may be the source of a secondarily infected farm in the Netherlands. One infected turkey farm in the province of Antwerp (Westmalle) was geographically close to the latter introduction, but genetically clustered with the first introduction event in the Limburg province. Epidemiological tracing data could neither confirm nor exclude whether this outbreak was a result from long distance contacts within Belgium or whether this farm presented a fourth independent transboundary introduction. These multiple transnational transmissions of HPAI in spite of reinforced biosecurity measures and trade restrictions illustrate the importance of international cooperation, legislation and standardization of tools to combat transboundary diseases.

Establishment of the first international repository for transfusion-relevant bacteria reference strains: ISBT working party transfusion-transmitted infectious diseases (WP-TTID), subgroup on bacteria

BACKGROUND

Bacterial contamination of platelet concentrates (PCs) still remains a significant problem in transfusion with potential important clinical consequences, including death. The International Society of Blood Transfusion Working Party on Transfusion-Transmitted Infectious Diseases, Subgroup on Bacteria, organised an international study on Transfusion-Relevant Bacteria References to be used as a tool for development, validation and comparison of both bacterial screening and pathogen reduction methods.

MATERIAL AND METHODS

Four Bacteria References (Staphylococcus epidermidis PEI-B-06, Streptococcus pyogenes PEI-B-20, Klebsiella pneumoniae PEI-B-08 and Escherichia coli PEI-B-19) were selected regarding their ability to proliferate to high counts in PCs and distributed anonymised to 14 laboratories in 10 countries for identification, enumeration and bacterial proliferation in PCs after low spiking (0·3 and 0·03 CFU/ml), to simulate contamination occurring during blood donation.

RESULTS

Bacteria References were correctly identified in 98% of all 52 identifications. S. pyogenes and E. coli grew in PCs in 11 out of 12 laboratories, and K. pneumoniae and S. epidermidis replicated in all participating laboratories. The results of bacterial counts were very consistent between laboratories: the 95% confidence intervals were for S. epidermidis: 1·19-1·32 × 10(7) CFU/ml, S. pyogenes: 0·58-0·69 × 10(7) CFU/ml, K. pneumoniae: 18·71-20·26 × 10(7) CFU/ml and E. coli: 1·78-2·10 × 10(7) CFU/ml.

CONCLUSION

The study was undertaken as a proof of principle with the aim to demonstrate (i) the quality, stability and suitability of the bacterial strains for low-titre spiking of blood components, (ii) the property of donor-independent proliferation in PCs, and (iii) their suitability for worldwide shipping of deep frozen, blinded pathogenic bacteria. These aims were successfully fulfilled. The WHO Expert Committee Biological Standardisation has approved the adoption of these four bacteria strains as the first Repository for Transfusion-Relevant Bacteria Reference Strains and, additionally, endorsed as a project the addition of six further bacteria strain preparations suitable for control of platelet contamination as the next step of enlargement of the repository.

Flow cytometric differentiation of avian leukocytes and analysis of their intracellular cytokine expression

A flow cytometric method for the identification of chicken blood leukocyte subpopulations and thrombocytes was developed. An anti-chicken CD45 phycoerythrin-labelled antibody was used to separate leukocytes from red blood cell nuclei. Leukocytes and thrombocytes were identified using a combination of their CD45-positivity and their typical side scatter properties. The identity of the CD45-positive cells was confirmed by sorting the subpopulations and subsequent light microscopic evaluation. In these differentiated cell populations, intracellular expression analysis of the proinflammatory cytokines interleukin-1beta and interleukin-6 was subsequently optimized on whole blood after in vitro stimulation with lipopolysaccharide from Escherichia coli strain O127:B8.

Prime-boost vaccination with a fowlpox vector and an inactivated avian influenza vaccine is highly immunogenic in Pekin ducks challenged with Asian H5N1 HPAI

The efficacy of different vaccination schedules was evaluated in 17-day-old Pekin ducks using an experimental inactivated whole virus vaccine based on the H5N9 A/chicken/Italy/22A/98 isolate (H5N9-It) and/or a fowlpox recombinant (vFP-H5) expressing a synthetic HA gene from an Asian H5N1 isolate (A/chicken/Indonesia/7/2003). Full protection against clinical signs and shedding was induced by the different vaccination schemes. However, the broadest antibody response and the lowest antibody increase after challenge were observed in the group of ducks whose immune system was primed with the fowlpox vectored vaccine and boosted with the inactivated vaccine, suggesting that this prime-boost strategy induced optimal immunity against H5N1 and minimal viral replication after challenge in ducks. In addition, this prime-boost vaccination scheme was shown to be immunogenic in 1-day-old ducklings.

Important research questions in allergy and related diseases: nonallergic rhinitis: a GA2LEN paper

Nonallergic rhinitis (NAR) can be defined as a chronic nasal inflammation which is not caused by systemic IgE-dependent mechanisms. It is common and probably affects far more than 200 million people worldwide. Both children and adults are affected. However, its exact prevalence is unknown and its phenotypes need to be evaluated using appropriate methods to better understand its pathophysiology, diagnosis and management. It is important to differentiate between infectious rhinitis, allergic/NAR and chronic rhinosinusitis, as management differs for each of these cases. Characterization of the phenotype, mechanisms and management of NAR represents one of the major unmet needs in allergic and nonallergic diseases. Studies on children and adults are required in order to appreciate the prevalence, phenotype, severity and co-morbidities of NAR. These studies should compare allergic and NAR and consider different age group populations including elderly subjects. Mechanistic studies should be carried out to better understand the disease(s) and risk factors and to guide towards an improved diagnosis and therapy. These studies need to take the heterogeneity of NAR into account. It is likely that neuronal mechanisms, T cells, innate immunity and possibly auto-immune responses all play a role in NAR and may also contribute to the symptoms of allergic rhinitis.

Lung dendritic cells: targets for therapy in allergic disease

Dendritic cells (DCs) are crucial in determining the functional outcome of allergen encounter in the lung. Antigen presentation by myeloid DCs leads to Th2 sensitization typical of allergic disease, whereas antigen presentation by plasmacytoid DCs serves to dampen inflammation. It is increasingly clear that DCs have an antigen presenting function beyond sensitization. DCs therefore constitute a novel target for the development of antiallergic therapy aimed at the origin of the inflammatory cascade. A careful study of DC biology and of the receptors expressed by lung DCs has provided a framework for the discovery of novel antiallergic compounds.

Efficacy of an Inactivated and a Fowlpox-Vectored Vaccine in Muscovy Ducks Against an Asian H5N1 Highly Pathogenic Avian Influenza Viral Challenge

The efficacy of an inactivated vaccine containing the Eurasian isolate A/chicken/Italy/22A/98 H5N9 (H5N9-It) was compared with that of the fowlpox-vectored TROVACTM-AIV H5 (rFP-AIV-H5) vaccine against an H5N1 highly pathogenic avian influenza challenge. Five-week-old Muscovy ducks were vaccinated with either H5N9-It (0.5 ml) or rFP-AIV-H5 (5 log10 50% tissue culture infectious dose (TCID50)/dose), followed by a boost at 7 wk of age with the same vaccine (1.0 ml of H5N9-It or 5 log10 TCID50/dose rFP-AIV-H5), and a challenge at 9 wk of age with 10(7) egg infectious dose (lethality 50%) of A/crested eagle/ Belgium/01/2004 (H5N1). All unvaccinated challenged birds showed severe nervous signs (loss of balance, torticollis) starting 7 days postinfection (dpi). None of the vaccinated ducks showed these nervous signs. Shedding was measured in oropharyngeal and cloacal swabs, sampled from 3 to 19 dpi by titration in chicken embryo fibroblasts and by real-time reverse transcription-polymerase chain reaction. Virus shedding was significantly higher in oropharyngeal compared to cloacal swabs. Both vaccines reduced the percentage of positive swabs and the viral load in the swabs, but the reduction was higher with the H5N9-It vaccine. The inactivated vaccine induced hemagglutination inhibition (HI) titers (5.4 log2) that were boosted after the second administration (7.5 log2). rFP-AIV-H5-induced HI titers were lower (3 log2 only after the second administration), most probably because the fowlpox vector does not replicate in ducks. Altogether, these results indicate that significant protection from clinical signs and reduction in virus shedding may be achieved in ducks with conventional inactivated or fowlpox-vectored vaccine as compared with nonvaccinated challenged control birds.

A Universal Avian Endogenous Real-Time Reverse Transcriptase–Polymerase Chain Reaction Control and Its Application to Avian Influenza Diagnosis and Quantification

Real-time reverse transcriptase-polymerase chain reaction (RRT-PCR) is becoming an established first-line diagnostic assay as well as a precise quantification tool for avian influenza virus detection. However, there remain some limitations. First, we show that the sensitivity of RRT-PCR influenza detection can be 10- to 100-fold inhibited in oropharyngeal and cloacal swabs. Adding 0.5 U of heat-activated Taq DNA polymerase successfully reverses PCR inhibition. Second, an excellent strategy for detecting false negative samples is the coamplification of an internal control from each sample. We developed a universal avian endogenous internal control (bird beta-actin) and apply it to influenza A diagnosis. Moreover, this internal control proves useful as a normalizer control for virus quantification, because beta-actin gene expression does not change in infected vs. uninfected ducks. A combined panel of wild bird cloacal swabs, wild bird tissue samples, experimental duck swabs, and experimental duck and chicken tissue samples was used to validate the endogenous control. The application of an endogenous internal control proves an excellent strategy both for avoiding false negative diagnostic results and for standardizing virus quantification studies.

Development of an M2e-Specific Enzyme-Linked Immunosorbent Assay for Differentiating Infected from Vaccinated Animals

Vaccination programs for the control of avian influenza (AI) in birds have restrictions because of some limited efficacy and the difficulty of discriminating between vaccinated and virus-infected poultry. We studied M2e, the highly conserved external domain of the influenza A M2 protein, as a potential differential diagnostic marker for influenza virus infection. The M2 protein is an integral membrane protein, scarcely present on virus particles, but abundantly expressed on virus-infected cells. M2e-specific enzyme-linked immunosorbent assays (ELISAs) for different avian influenza strains were developed by coating the peptides corresponding to the first 18 amino acids, without the first methionine, of the universal human consensus M2e sequence and the specific M2e sequence of two highly pathogenic AI (HPAI) strains, H7N7 and H5N1. Using the M2e ELISAs, M2e-specific antibodies were observed in chickens and ducks experimentally infected with H7 or H5 HPAI, respectively, that correlated well with hemagglutination inhibition (HI) antibodies. Conversely, sera from chicken and ducks inoculated with inactivated AI vaccines were positive for HI test but negative for the M2e ELISAs. Moreover, ducks inoculated with inactivated vaccine and challenged with a HPAI H5N1 seroconverted for antibodies to the M2e peptide, with significantly different levels from those measured between the vaccinated and infected groups. These results indicate the potential benefit of a simple and specific M2e ELISA in the assessment of the efficacy of vaccination as well as for diagnostic and survey applications.

Oxygen saturation measured in vivo in bronchial tumors during bronchoscopy in patients with lung cancer using differential path length spectroscopy (DPS) correlates with survival, stage of the disease, and expression of HIF1a

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Background: Tumor hypoxia is known to correlate with poor prognosis in solid cancers. In bronchial tumors direct determination of oxygen saturation is not possible and therefore indirect measures like hypoxia related proteins as HIF1a have been studied. We studied the prognostic significance on patient survival and tumor stage of microvascular oxygen saturation (StO2) measured in vivo in bronchial tumors using optical spectroscopy and compared this to HIF1a expression in bronchial biopsies. Methods: DPS is a non-invasive real-time measurement of hypoxia related parameters such as microvascular blood oxygenation (StO2) which can be used during bronchoscopy (Bard Am J Respir Crit Care Med 2005). Endobronchial tumors (12 squamous cell carcinomas, 5 adenocarcinomas, 15 large cell undifferentiated and 6 small cell carcinomas), were measured in 38 patients. In a subgroup of patients HIF1a expression was related to StO2 using linear regression analysis. Results: StO2 of bronchial tumors was predictive for patient survival. Patients with an endobronchial tumor and a saturation lower than the median value of 52% had a significant shorter overall survival than patients with a better saturated tumor. The StO2 was also related to the stage of the disease. StO2 was significantly lower in case of advanced lung tumors (stage III & IV, StO2= 44.7 ± 24.7%) in comparison with localized lung tumors (stage I&II, StO2 = 73.3 ± 12.4) (p<0.05). StO2 correlated to HIF1a expression levels (r = −0.65). Conclusions: StO2 using DPS correlates with HIF1a expression, is related to tumor stage and is a prognositc factor. This opens a new field for study of therapeutic agents in lung cancer and may also be important in the staging of lung cancer.

No significant financial relationships to disclose.

Turkey and chicken interferon-gamma, which share high sequence identity, are biologically cross-reactive

Turkey and chicken interferon-gamma (IFN-gamma) share high identity (96.3% and 97% at the nucleotide and amino acid level, respectively). As such, we predicted that they would be functionally cross-reactive. To test this hypothesis, we produced recombinant turkey and chicken IFN-gamma, and compared their biological properties. Recombinant turkey and chicken IFN-gamma both induce HD11 cells (a chicken macrophage cell line) and LSTC-IAH30 cells (ALV-J-transformed turkey macrophages) to produce nitric oxide (NO), as measured in an avian IFN-gamma bioassay. Polyclonal and monoclonal antibodies, capable of neutralising the effect of chicken IFN-gamma on HD11 cells, were also shown to inhibit the activity of turkey IFN-gamma on these cells. The antibody neutralisation effect on both turkey and chicken IFN-gamma was shown by a significant reduction in NO production by HD11 cells when the neutralising antibodies were present in the bioassay. FACS analysis showed that HD11 and LSTC-IAH30 cells share some cell surface markers.

Tuberculosis DNA vaccine encoding Ag85A is immunogenic and protective when administered by intramuscular needle injection but not by epidermal gene gun bombardment

Immunogenicity and protective efficacy of a DNA vaccine encoding Ag85A from Mycobacterium tuberculosis were compared in BALB/c and C57BL (B6 and B10) mice immunized by intramuscular (i.m.) needle injection or epidermal gene gun (gg) bombardment. In BALB/c mice, gg immunization could induce elevated antibody and cytotoxic T lymphocyte responses with plasmid doses 50-fold lower than those required for i.m. immunization. Interleukin-2 (IL-2) and gamma interferon (IFN-gamma) secretion, however, was much lower in gg-immunized than in i.m.-immunized BALB/c mice. On the other hand, C57BL mice reacted only very weakly to gg immunization, whereas elevated Ag85A-specific antibody, IL-2, and IFN-gamma responses (significantly higher than in BALB/c mice) were detected following vaccination by the i.m. route. Antibody isotypes were indicative of Th2 activation following gg injection of BALB/c and of Th1 activation following i.m. injection of C57BL mice. Finally, C57BL but not BALB/c mice were protected by i.m. Ag85A DNA immunization against intravenous M. tuberculosis challenge, as measured by reduced numbers of CFU in spleen and lungs, compared to animals vaccinated with control DNA. Gene gun immunization was not effective in either BALB/c or C57BL mice. These results indicate that i.m. DNA vaccination is the method of choice for the induction of protective Th1 type immune responses with the Ag85A tuberculosis DNA vaccine.