The adjuvant component α-tocopherol triggers via modulation of Nrf2 the expression and turnover of hypocretin in vitro and its implication to the development of narcolepsy

Narcolepsy and H1N1 influenza immunology a decade later: What have we learned?

In the wake of the A/California/7/2009 H1N1 influenza pandemic vaccination campaigns in 2009-2010, an increased incidence of the chronic sleep-wake disorder narcolepsy was detected in children and adolescents in several European countries. Over the last decade, in-depth epidemiological and immunological studies have been conducted to investigate this association, which have advanced our understanding of the events underpinning the observed risk. Narcolepsy with cataplexy (defined as type-1 narcolepsy, NT1) is characterized by an irreversible and chronic deficiency of hypocretin peptides in the hypothalamus. The multifactorial etiology is thought to include genetic predisposition, head trauma, environmental triggers, and/or infections (including influenza virus infections), and an increased risk was observed following administration of the A/California/7/2009 H1N1 vaccine Pandemrix (GSK). An autoimmune origin of NT1 is broadly assumed. This is based on its strong association with a predisposing allele (the human leucocyte antigen DQB1*0602) carried by the large majority of NT1 patients, and on links with other immune-related genetic markers affecting the risk of NT1. Presently, hypotheses on the underlying potential immunological mechanisms center on molecular mimicry between hypocretin and peptides within the A/California/7/2009 H1N1 virus antigen. This molecular mimicry may instigate a cross-reactive autoimmune response targeting hypocretin-producing neurons. Local CD4⁺ T-cell responses recognizing peptides from hypocretin are thought to play a central role in the response. In this model, cross-reactive DQB1*0602-restricted T cells from the periphery would be activated to cross the blood-brain barrier by rare, and possibly pathogen-instigated, inflammatory processes in the brain. Current hypotheses suggest that activation and expansion of cross-reactive T-cells by H1N1/09 influenza infection could have been amplified following the administration of the adjuvanted vaccine, giving rise to a “two-hit” hypothesis. The collective in silico, in vitro, and preclinical in vivo data from recent and ongoing research have progressively refined the hypothetical model of sequential immunological events, and filled multiple knowledge gaps. Though no definitive conclusions can be drawn, the mechanistical model plausibly explains the increased risk of NT1 observed following the 2009-2010 H1N1 pandemic and subsequent vaccination campaign, as outlined in this review.

Population-Based Incidence of Guillain-Barré Syndrome During Mass Immunization With Viral Vaccines: A Pooled Analysis

Misunderstanding temporal coincidence of adverse events during mass vaccination and invalid assessment of possible safety concerns have negative effects on immunization programs, leading to low immunization coverage. We conducted this systematic review and meta-analysis to identify the incidence rates of GBS that are temporally associated with viral vaccine administration but might not be attributable to the vaccines. By literature search in Embase and PubMed, we included 48 publications and 2,110,441,600 participants. The pooled incidence rate of GBS was 3.09 per million persons (95% confidence interval [CI]: 2.67 to 3.51) within six weeks of vaccination, equally 2.47 per 100,000 person-year (95%CI: 2.14 to 2.81). Subgroup analyses illustrated that the pooled rates were 2.77 per million persons (95%CI: 2.47 to 3.07) for individuals who received the influenza vaccine and 2.44 per million persons (95%CI: 0.97 to 3.91) for human papillomavirus (HPV) vaccines, respectively. Our findings evidence the GBS-associated safety of virus vaccines. We present a reference for the evaluation of post-vaccination GBS rates in mass immunization campaigns, including the SARS-CoV-2 vaccine.

Role of Vitamin E and the Orexin System in Neuroprotection

Microglia are the first line of defense at the level of the central nervous system (CNS). Phenotypic change in microglia can be regulated by various factors, including the orexin system. Neuroinflammation is an inflammatory process mediated by cytokines, by the lack of interaction between neurotransmitters and their specific receptors, caused by systemic tissue damage or, more often, associated with direct damage to the CNS. Chronic activation of microglia could lead to long-term neurodegenerative diseases. This review aims to explore how tocopherol (vitamin E) and the orexin system may play a role in the prevention and treatment of microglia inflammation and, consequently, in neurodegenerative diseases thanks to its antioxidant properties. The results of animal and in vitro studies provide evidence to support the use of tocopherol for a reduction in microglia inflammation as well as a greater activation of the orexinergic system. Although there is much in vivo and in vitro evidence of vitamin E antioxidant and protective abilities, there are still conflicting results for its use as a treatment for neurodegenerative diseases that speculate that vitamin E, under certain conditions or genetic predispositions, can be pro-oxidant and harmful.

Physiology of gangliosides and the role of antiganglioside antibodies in human diseases

Gangliosides are structurally and functionally polymorphic sialic acid containing glycosphingolipids that are widely distributed in the human body. They play important roles in protecting us against immune attacks, yet they can become targets for autoimmunity and act as receptors for microbes, like the influenza viruses, and toxins, such as the cholera toxin. The expression patterns of gangliosides vary in different tissues, during different life periods, as well as in different animals. Antibodies against gangliosides (AGA) can target immune attack e.g., against neuronal cells and neutralize their complement inhibitory activity. AGAs are important especially in acquired demyelinating immune-mediated neuropathies, like Guillain-Barré syndrome (GBS) and its variant, the Miller-Fisher syndrome (MFS). They can emerge in response to different microbial agents and immunological insults. Thereby, they can be involved in a variety of diseases. In addition, antibodies against GM3 were found in the sera of patients vaccinated with Pandemrix®, who developed secondary narcolepsy, strongly supporting the autoimmune etiology of the disease.

Regulation of the Transferrin Receptor Recycling in Hepatitis C Virus-Replicating Cells

After binding of its ligand transferrin, the transferrin receptor (TfR) is internalized via early endosomes. Ligand and receptor can be recycled. α-Taxilin was identified as an essential factor for TfR recycling. Apart from its role for iron uptake, TfR is a coreceptor for hepatitis C virus (HCV) infection. In HCV-replicating cells, the amount of a-taxilin is decreased. This study aims to investigate the effect of decreased α-taxilin levels in HCV-replicating cells on recycling of TfR, its amount on the cell surface, on iron uptake, and the impact of a disturbed TfR recycling on HCV superinfection exclusion. TfR amount and localization were determined by CLSM and surface biotinylation. α-taxilin expression was modulated by CRISPR-Cas9 knockout, siRNA, and stable or transient overexpression. For analysis of HCV superinfection fluorophor-tagged reporter viruses were used. The amount of α-taxilin is decreased in HCV-infected cells. In accordance to this, the protein amount of TfR is significant lower in HCV-positve cells as compared to the control, while TfR expression is not affected. Due to the impaired recycling, internalized TfR is degraded by the endosomal/lysosomal system. The significant lower number of TfR molecules on the cell surface is reflected by reduced transferrin binding/internalization and strong reduction of intracellular iron level. Overexpression of α-taxilin in HCV-replicating cells rescues TfR recycling, augments TfR on the cell surface, and restores transferrin binding. The block of superinfection in HCV-replicating cells could be overcome by overexpression of α-taxilin. Taken together, the diminished level of α-taxilin in HCV-replicating cells prevents recycling of TfR leading to decreased transferrin binding and iron uptake. Disappearance of TfR from the cell surface could be a factor contributing to the exclusion of superinfection by HCV.

Discovery of Keap1-Nrf2 small-molecule inhibitors from phytochemicals based on molecular docking

Various phytochemicals have been reported to protect against oxidative stress. However, the mechanism underlying has not been systematically evaluated, which limited their application in disease treatment. Nuclear factor erythroid 2−related factor 2 (Nrf2), a central transcription factor in oxidative stress response related to numerous diseases, is activated after dissociating from the cytoskeleton−anchored Kelch−like ECH−associated protein 1 (Keap1). The Keap1–Nrf2 protein–protein interaction has become an important drug target. This study was designed to clarify whether antioxidantive phytochemicals inhibit the Keap1–Nrf2 protein–protein interaction and activate the Nrf2-ARE signaling pathway efficiently. Molecular docking and 3D−QSAR were applied to evaluate the interaction effects between 178 antioxidant phytochemicals and the Nrf2 binding site in Keap1. The Nrf2 activation effect was tested on a H₂O₂−induced oxidative−injured cell model. Results showed that the 178 phytochemicals could be divided into high−, medium−, and low−total−score groups depending on their binding affinity with Keap1, and the high−total−score group consisted of 24 compounds with abundant oxygen or glycosides. Meanwhile, these compounds could bind with key amino acids in the structure of the Keap1−Nrf2 interface. Compounds from high−total−score group show effective activation effects on Nrf2. In conclusion, phytochemicals showed high binding affinity with Keap1 are promising new Nrf2 activators.

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178 phytochemicals were collected and the Keap1-binding-affinity was estimated.

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24 compounds with high Keap1-binding-affinity was obtained.

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Compounds with high Keap1-binding-affinity effectively activated Nrf2.

[Composition and mode of action of adjuvants in licensed viral vaccines]

The immunogenicity and efficacy of vaccines is largely governed by nature and the amount of antigen(s) included. Specific immune-stimulating substances, so-called adjuvants, are added to vaccine formulations to enhance and modulate the induced immune response.Adjuvants are very different in their physicochemical nature and are primarily characterized by their immune-enhancing effects. In this report, adjuvants that are components of vaccines licensed in the EU will be presented and their mode of action will be discussed.Aluminum salts have been used for almost a century as vaccine adjuvants. In recent years numerous novel immune-stimulating substances have been developed and integrated into licensed human vaccines. These novel adjuvants are not only intended to generally increase the vaccine-induced antibody titers, but are also aimed at modulating and triggering a specific immune response. The search for innovative adjuvants was considerably stimulated during development of pandemic influenza vaccines. By using squalene-containing oil-in-water adjuvants (namely AS03 and MF59), pandemic influenza vaccines were developed that were efficacious despite a significant reduction of the antigen content.The development of novel adjuvants is a highly dynamic and essential area in modern vaccine design. Some years ago, vaccines for prevention of HPV-induced cervix carcinoma and hepatitis B were licensed that contained the toll-like receptor 4 agonist 3‑O-desacyl-monophosphoryl lipid A (MPL), a detoxified LPS version, as the adjuvant. Quite recently, a herpes zoster vaccine was licensed in Europe with a combination of MPL and the saponin QS21 as adjuvant. This combination of immune enhancers is also used in the formulations of the same manufacturer's malaria and hepatitis B vaccine.

Molecular mechanisms of neuroprotective effect of adjuvant therapy with phenytoin in pentylenetetrazole-induced seizures: Impact on Sirt1/NRF2 signaling pathways

Current anticonvulsant therapies are principally aimed at suppressing neuronal hyperexcitability to prevent or control the incidence of seizures. However, the role of oxidative stress processes in seizures led to the proposition that antioxidant compounds may be considered as promising candidates for limiting the progression of epilepsy. Accordingly, the aim of this study is to determine if coenzyme Q10 (CoQ10) and alpha-tocopherol (α-Toc) have a neuroprotective effect in rats against the observed oxidative stress and inflammation during seizures induced by pentylenetetrazole (PTZ) in rats, and to study their interactions with the conventional antiseizure drug phenytoin (PHT), either alone or in combination. Overall, the data revealed that α-Toc and CoQ10 supplementation can ameliorate PTZ-induced seizures and recommended that nuclear factor erythroid 2-related factor 2 (NRF2) and silencing information regulator 1 (Sirt1) signaling pathways may exemplify strategic molecular targets for seizure therapies. The results of the present study provide novel mechanistic insights regarding the protective effects of antioxidants and suggest an efficient therapeutic strategy to attenuate seizures. Additionally, concurrent supplementation of CoQ10 and α-Toc may be more effective than either antioxidant alone in decreasing inflammation and oxidative stress in both cortical and hippocampal tissues. Also, CoQ10 and α-Toc effectively reverse the PHT-mediated alterations in the brain antioxidant status when compared to PHT only.

Inhibition of Zika Virus Replication by Silvestrol

The Zika virus (ZIKV) outbreak in 2016 in South America with specific pathogenic outcomes highlighted the need for new antiviral substances with broad-spectrum activities to react quickly to unexpected outbreaks of emerging viral pathogens. Very recently, the natural compound silvestrol isolated from the plant Aglaia foveolata was found to have very potent antiviral effects against the (−)-strand RNA-virus Ebola virus as well as against Corona- and Picornaviruses with a (+)-strand RNA-genome. This antiviral activity is based on the impaired translation of viral RNA by the inhibition of the DEAD-box RNA helicase eukaryotic initiation factor-4A (eIF4A) which is required to unwind structured 5´-untranslated regions (5′-UTRs) of several proto-oncogenes and thereby facilitate their translation. Zika virus is a flavivirus with a positive-stranded RNA-genome harboring a 5′-capped UTR with distinct secondary structure elements. Therefore, we investigated the effects of silvestrol on ZIKV replication in A549 cells and primary human hepatocytes. Two different ZIKV strains were used. In both infected A549 cells and primary human hepatocytes, silvestrol has the potential to exert a significant inhibition of ZIKV replication for both analyzed strains, even though the ancestor strain from Uganda is less sensitive to silvestrol. Our data might contribute to identify host factors involved in the control of ZIKV infection and help to develop antiviral concepts that can be used to treat a variety of viral infections without the risk of resistances because a host protein is targeted.

AS03- and MF59-Adjuvanted Influenza Vaccines in Children

Influenza is a major cause of respiratory disease leading to hospitalization in young children. However, seasonal trivalent influenza vaccines (TIVs) have been shown to be ineffective and poorly immunogenic in this population. The development of live-attenuated influenza vaccines and adjuvanted vaccines are important advances in the prevention of influenza in young children. The oil-in-water emulsions MF59 and adjuvant systems 03 (AS03) have been used as adjuvants in both seasonal adjuvanted trivalent influenza vaccines (ATIVs) and pandemic monovalent influenza vaccines. Compared with non-adjuvanted vaccine responses, these vaccines induce a more robust and persistent antibody response for both homologous and heterologous influenza strains in infants and young children. Evidence of a significant improvement in vaccine efficacy with these adjuvanted vaccines resulted in the use of the monovalent (A/H1N1) AS03-adjuvanted vaccine in children in the 2009 influenza pandemic and the licensure of the seasonal MF59 ATIV for children aged 6 months to 2 years in Canada. The mechanism of action of MF59 and AS03 remains unclear. Adjuvants such as MF59 induce proinflammatory cytokines and chemokines, including CXCL10, but independently of type-1 interferon. This proinflammatory response is associated with improved recruitment, activation and maturation of antigen presenting cells at the injection site. In young children MF59 ATIV produced more homogenous and robust transcriptional responses, more similar to adult-like patterns, than did TIV. Early gene signatures characteristic of the innate immune response, which correlated with antibody titers were also identified. Differences were detected when comparing child and adult responses including opposite trends in gene set enrichment at day 3 postvaccination and, unlike adult data, a lack of correlation between magnitude of plasmablast response at day 7 and antibody titers at day 28 in children. These insights show the utility of novel approaches in understanding new adjuvants and their importance for developing improved influenza vaccines for children.

In Vitro Evaluation of Glycoengineered RSV-F in the Human Artificial Lymph Node Reactor

Subunit vaccines often require adjuvants to elicit sustained immune activity. Here, a method is described to evaluate the efficacy of single vaccine candidates in the preclinical stage based on cytokine and gene expression analysis. As a model, the recombinant human respiratory syncytial virus (RSV) fusion protein (RSV-F) was produced in CHO cells. For comparison, wild-type and glycoengineered, afucosylated RSV-F were established. Both glycoprotein vaccines were tested in a commercial Human Artificial Lymph Node in vitro model (HuALN^®). The analysis of six key cytokines in cell culture supernatants showed well-balanced immune responses for the afucosylated RSV-F, while immune response of wild-type RSV-F was more Th1 accentuated. In particular, stronger and specific secretion of interleukin-4 after each round of re-stimulation underlined higher potency and efficacy of the afucosylated vaccine candidate. Comprehensive gene expression analysis by nCounter gene expression assay confirmed the stronger onset of the immunologic reaction in stimulation experiments with the afucosylated vaccine in comparison to wild-type RSV-F and particularly revealed prominent activation of Th17 related genes, innate immunity, and comprehensive activation of humoral immunity. We, therefore, show that our method is suited to distinguish the potency of two vaccine candidates with minor structural differences.

HX-1171, a Novel Nrf2 Activator, Induces NQO1 and HMOX1 Expression

HX-1171 (1-O-hexyl-2,3,5-trimethylhydroquinone) is a novel synthesized vitamin E derivative, which reportedly has positive effects on various diseases and conditions, such as liver fibrosis, hepatic cirrhosis, and cancer. In this study, we analyzed the transcriptional activity induced by HX-1171. Results from reverse transcription polymerase chain reaction and promoter assays reveal that HX-1171 increased the expression of NQO1 and HMOX1, encoding antioxidant-related enzymes, in A549 human lung epithelial cells. The activity of nuclear factor-E2-related factor (Nrf2), a key transcriptional factor for antioxidative enzymes, was examined in HX-1171-treated cells. Confocal microscopy and Western blotting showed that HX-1171 effectively induced the nuclear translocation and transcriptional activity of Nrf2. We conclude that HX-1171, a novel Nrf2 activator, may be a promising therapeutic agent for oxidative stress-induced diseases. J. Cell. Biochem. 118: 3372-3380, 2017. © 2017 Wiley Periodicals, Inc.

The Intracellular Cholesterol Transport Inhibitor U18666A Inhibits the Exosome-Dependent Release of Mature Hepatitis C Virus

Hepatitis C virus (HCV) particles are described as lipoviroparticles which are released similarly to very-low-density lipoproteins (VLDLs). However, the release mechanism is still poorly understood; the canonical endoplasmic reticulum-Golgi intermediate compartment (ERGIC) pathway as well as endosome-dependent release has been proposed. Recently, the role of exosomes in the transmission of HCV has been reported. Only a minor fraction of the de novo-synthesized lipoviroparticles is released by the infected cell. To investigate the relevance of multivesicular bodies (MVBs) for viral morphogenesis and release, the MVB inhibitor U18666A was used. Intracellular trafficking was analyzed by confocal microscopy and electron microscopy. Moreover, an mCherry-tagged HCV variant was used. Conditions were established that enable U18666A-dependent inhibition of MVBs without affecting viral replication. Under these conditions, significant inhibition of the HCV release was observed. The assembly of viral particles is not affected. In U18666A-treated cells, intact infectious viral particles accumulate in CD63-positive exosomal structures and large dysfunctional lysosomal structures (multilamellar bodies). These retained particles possess a lower density, reflecting a misloading with lipids. Our data indicate that at least a fraction of HCV particles leaves the cell via the endosomal pathway. Endosomes facilitate the sorting of HCV particles for release or degradation.

IMPORTANCE

There are still a variety of open questions regarding morphogenesis and release of hepatitis C virus. The HCV-infected cell produces significant more viral particles that are released, raising the question about the fate of the nonreleased particles. Moreover, the relevance of the endosomal pathway for the release of HCV is under debate. Use of the MVB (multivesicular body) inhibitor U18666A enabled a detailed analysis of the impact of MVBs for viral morphogenesis and release. It was revealed that infectious, fully assembled HCV particles are either MVB-dependently released or intracellularly degraded by the lysosome. Our data indicate that at least a fraction of HCV particles leaves the cell via the endosomal pathway independent from the constitutive secretory pathway. Our study describes a so-far-unprecedented cross talk between two pathways regulating on the one hand the release of infectious viral particles and on the other hand the intracellular degradation of nonreleased particles.

Vitamins as influenza vaccine adjuvant components

A number of adjuvant formulations were assayed in mice immunized with 3.75 µg of A/California/7/2009 (H1N1) pdm09 influenza vaccine with vitamins A, D and/or E in emulsions or B2 and/or B9 combined with Bordetella pertussis MPLA and/or alum as adjuvants. Squalene was used as positive control, as well as MPLA with alum. The immune response was evaluated by a panel of tests, including a hemagglutination inhibition (HAI) test, ELISA for IgG, IgG1, and IgG2a and IFN-γ, IL-2, IL-6 and IL-10 quantification in splenocyte culture supernatant after stimulus with influenza antigen. Immunological memory was evaluated using a 1/10 dose booster 60 days after the first immunization followed by assessment of the response by HAI, IgG ELISA, and determination of the antibody affinity index. The highest increases in HAI, IgG1 and IgG2a titers were obtained with the adjuvant combinations containing vitamin E, or the hydrophilic combinations containing MPLA and alum or B2 and alum. The IgG1/IgG2a ratio indicates that the response to the combination of B2 with alum would have more Th2 character than the combination of MPLA with alum. In an assay to investigate the memory response, a significant increase in HAI titer was observed with a booster vaccine dose at 60 days after immunization with vaccines containing MPLA with alum or B2 with alum. Overall, of the 27 adjuvant combinations, MPLA with alum and B2 with alum were the most promising adjuvants to be evaluated in humans.

The Autophagosomal SNARE Protein Syntaxin 17 Is an Essential Factor for the Hepatitis C Virus Life Cycle

Syntaxin 17 is an autophagosomal SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein required for the fusion of autophagosomes with lysosomes to form autolysosomes and thereby to deliver the enclosed contents for degradation. Hepatitis C virus (HCV) induces autophagy. In light of the observation that the number of viral particles formed by HCV-infected cells is much greater than the number of infectious viral particles finally released by HCV-infected cells, the regulation of fusion between autophagosomes and lysosomes might fulfill a key function controlling the number of released virions. HCV-replicating cells possess a decreased amount of syntaxin 17 due to impaired expression and increased turnover of syntaxin 17. Overexpression of syntaxin 17 in HCV-replicating cells diminishes the number of released infectious viral particles and decreases the amount of intracellular retained viral particles by favoring the formation of autolysosomes, in which HCV particles are degraded. Inhibition of lysosomal acidification by bafilomycin rescues the decreased release of virions from syntaxin 17-overexpressing cells, while induction of autophagy by rapamycin enforces the impairment of release under these conditions. Vice versa, inhibition of syntaxin 17 expression by specific small interfering RNAs results in an elevated amount of intracellular retained viral particles and facilitates the release of HCV virions by impairment of autophagosome-lysosome fusion. HCV genome replication, however, is not affected by modulation of syntaxin 17 expression. These data identify syntaxin 17 to be a novel factor controlling the release of HCV. This is achieved by regulation of autophagosome-lysosome fusion, which affects the equilibrium between the release of infectious viral particles and lysosomal degradation of intracellular retained viral particles.

IMPORTANCE

Hepatitis C virus (HCV) induces autophagy. Syntaxin 17 is an autophagosomal SNARE protein required for the fusion of autophagosomes with lysosomes. In HCV-infected cells, a major fraction of the de novo-synthesized viral particles is not released but is intracellularly degraded. In this context, the effect of HCV on the amount and distribution of syntaxin 17 and the relevance of syntaxin 17 for the viral life cycle were investigated. This study demonstrates that the amount of syntaxin 17 decreased in HCV-replicating cells. In addition, syntaxin 17 is identified to be a novel factor controlling the release of HCV, and the relevance of autophagosome-lysosome fusion as a regulator of the amount of released viral particles is revealed. Taken together, these findings indicate that syntaxin 17 is involved in the regulation of autophagosome-lysosome fusion and thereby affects the equilibrium between the release of infectious viral particles and the lysosomal degradation of intracellularly retained viral particles.

HCV and Oxidative Stress: Implications for HCV Life Cycle and HCV-Associated Pathogenesis

HCV (hepatitis C virus) is a member of the Flaviviridae family that contains a single-stranded positive-sense RNA genome of approximately 9600 bases. HCV is a major causative agent for chronic liver diseases such as steatosis, fibrosis, cirrhosis, and hepatocellular carcinoma which are caused by multifactorial processes. Elevated levels of reactive oxygen species (ROS) are considered as a major factor contributing to HCV-associated pathogenesis. This review summarizes the mechanisms involved in formation of ROS in HCV replicating cells and describes the interference of HCV with ROS detoxifying systems. The relevance of ROS for HCV-associated pathogenesis is reviewed with a focus on the interference of elevated ROS levels with processes controlling liver regeneration. The overview about the impact of ROS for the viral life cycle is focused on the relevance of autophagy for the HCV life cycle and the crosstalk between HCV, elevated ROS levels, and the induction of autophagy.

The safety of influenza vaccines in children: An Institute for Vaccine Safety white paper

Most influenza vaccines are generally safe, but influenza vaccines can cause rare serious adverse events. Some adverse events, such as fever and febrile seizures, are more common in children than adults. There can be differences in the safety of vaccines in different populations due to underlying differences in genetic predisposition to the adverse event. Live attenuated vaccines have not been studied adequately in children under 2 years of age to determine the risks of adverse events; more studies are needed to address this and several other priority safety issues with all influenza vaccines in children. All vaccines intended for use in children require safety testing in the target age group, especially in young children. Safety of one influenza vaccine in children should not be extrapolated to assumed safety of all influenza vaccines in children. The low rates of adverse events from influenza vaccines should not be a deterrent to the use of influenza vaccines because of the overwhelming evidence of the burden of disease due to influenza in children.

Anti-Infectious Human Vaccination in Historical Perspective

A brief history of vaccination is presented since the Jenner's observation, through the first golden age of vaccinology (from Pasteur's era to 1938), the second golden age (from 1940 to 1970), until the current period. In the first golden age, live, such as Bacille Calmette Guérin (BCG), and yellow fever, inactivated, such as typhoid, cholera, plague, and influenza, and subunit vaccines, such as tetanus and diphtheria toxoids, have been developed. In the second golden age, the cell culture technology enabled polio, measles, mumps, and rubella vaccines be developed. In the era of modern vaccines, in addition to the conjugate polysaccharide, hepatitis A, oral typhoid, and varicella vaccines, the advent of molecular biology enabled to develop hepatitis B, acellular pertussis, papillomavirus, and rotavirus recombinant vaccines. Great successes have been achieved in the fight against infectious diseases, including the smallpox global eradication, the nearly disappearance of polio, the control of tetanus, diphtheria, measles, rubella, yellow fever, and rabies. However, much work should still be done for improving old vaccines, such as BCG, anthrax, smallpox, plague, or for developing effective vaccines against old or emerging infectious threats, such as human-immunodeficiency-virus, malaria, hepatitis C, dengue, respiratory-syncytial-virus, cytomegalovirus, multiresistant bacteria, Clostridium difficile, Ebola virus. In addition to search for innovative and effective vaccines and global infant coverage, even risk categories should adequately be protected. Despite patients under immunosuppressive therapy are globally increasing, their vaccine coverage is lower than recommended, even in developed and affluent countries.

Characterization of α-taxilin as a novel factor controlling the release of hepatitis C virus

Although it is well established that the release of HCV (hepatitis C virus) occurs through the secretory pathway, many aspects concerning the control of this process are not yet fully understood. α-Taxilin was identified as a novel binding partner of syntaxin-4 and of other members of the syntaxin family, which are part of SNARE (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor) complexes and so are involved in intracellular vesicle traffic. Since α-taxilin prevents t-SNARE (target SNARE) formation by binding exclusively to free syntaxin-4, it exerts an inhibitory effect on the vesicular transport. HCV-replicating Huh7.5 cells and HCV-infected primary human hepatocytes and liver samples of patients suffering from chronic HCV contain significantly less α-taxilin compared with the controls. HCV impairs the expression of α-taxilin via NS5A-dependent interruption of the Raf/MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] signal transduction cascade. Moreover, the half-life of α-taxilin is significantly reduced in HCV-replicating cells. Whereas modulation of α-taxilin expression does not significantly affect genome replication, the overexpression of α-taxilin prevents the release of HCV. In contrast with this, silencing of α-taxilin expression leads to increased release of infectious viral particles. This is due to the negative effect of α-taxilin on t-SNARE formation that leads to impaired vesicular trafficking. Accordingly, overexpression of the t-SNARE component syntaxin-4 increases release of HCV, whereas silencing leads to an impaired release. These data identify α-taxilin as a novel factor that controls the release of HCV and reveal the mechanism by which HCV controls the activity of α-taxilin.

Incidence of narcolepsy before and after MF59-adjuvanted influenza A(H1N1)pdm09 vaccination in South Korean soldiers

BACKGROUND

Previous reports mostly from Europe suggested an association between an occurrence of narcolepsy and an influenza A(H1N1)pdm09 vaccine adjuvanted with AS03 (Pandemrix(®)). During the 2009 H1N1 pandemic vaccination campaign, the Korean military performed a vaccination campaign with one type of influenza vaccine containing MF59-adjuvants. This study was conducted to investigate the background incidence rate of narcolepsy in South Korean soldiers and the association of the MF59-adjuvanted vaccine with the occurrence of narcolepsy in a young adult group.

METHODS

To assess the incidence of narcolepsy, we retrospectively reviewed medical records of suspicious cases of narcolepsy in 2007-2013 in the whole 20 military hospitals of the Korean military. The screened cases were classified according to the Brighton Collaboration case definition of narcolepsy. After obtaining the number of confirmed cases of narcolepsy per 3 months in 2007-2013, we compared the crude incidence rate of narcolepsy before and after the vaccination campaign.

RESULTS

We included 218 narcolepsy suspicious cases in the initial review, which were screened by the diagnostic code on the computerized disease registry in 2007-2013. Forty-one cases were finally diagnosed with narcolepsy in 2007-2013 (male sex, 95%; median age, 21 years). The average background incidence rate of narcolepsy in Korean soldiers was 0.91 cases per 100,000 persons per year. During the 9 months before vaccination implementation (April to December 2009), 6 narcolepsy cases occurred, whereas during the next 9 months (January to September 2010) including the 3-month vaccination campaign, 5 cases occurred.

CONCLUSIONS

The incidence of narcolepsy in South Korean soldiers was not increased after the pandemic vaccination campaign using the MF59-adjuvanted vaccine. Our results suggest that the MF59-adjuvanted H1N1 vaccine did not contribute to the occurrence of narcolepsy in this young adult group.

Hypocretin (orexin) biology and the pathophysiology of narcolepsy with cataplexy

The discovery of hypocretins (orexins) and their causal implication in narcolepsy is the most important advance in sleep research and sleep medicine since the discovery of rapid eye movement sleep. Narcolepsy with cataplexy is caused by hypocretin deficiency owing to destruction of most of the hypocretin-producing neurons in the hypothalamus. Ablation of hypocretin or hypocretin receptors also leads to narcolepsy phenotypes in animal models. Although the exact mechanism of hypocretin deficiency is unknown, evidence from the past 20 years strongly favours an immune-mediated or autoimmune attack, targeting specifically hypocretin neurons in genetically predisposed individuals. These neurons form an extensive network of projections throughout the brain and show activity linked to motivational behaviours. The hypothesis that a targeted immune-mediated or autoimmune attack causes the specific degeneration of hypocretin neurons arose mainly through the discovery of genetic associations, first with the HLA-DQB1*06:02 allele and then with the T-cell receptor α locus. Guided by these genetic findings and now awaiting experimental testing are models of the possible immune mechanisms by which a specific and localised brain cell population could become targeted by T-cell subsets. Great hopes for the identification of new targets for therapeutic intervention in narcolepsy also reside in the development of patient-derived induced pluripotent stem cell systems.