Guanylate-binding protein 1 acts as a pro-viral factor for the life cycle of hepatitis C virus.

Viral infections trigger the expression of interferons (IFNs) and interferon stimulated genes (ISGs), which are crucial to modulate an antiviral response. The human guanylate binding protein 1 (GBP1) is an ISG and exhibits antiviral activity against several viruses. In a previous study, GBP1 was described to impair replication of the hepatitis C virus (HCV). However, the impact of GBP1 on the HCV life cycle is still enigmatic. To monitor the expression and subcellular distribution of GBP1 and HCV we performed qPCR, Western blot, CLSM and STED microscopy, virus titration and reporter gene assays. In contrast to previous reports, we observed that HCV induces the expression of GBP1. Further, to induce GBP1 expression, the cells were stimulated with IFNγ. GBP1 modulation was achieved either by overexpression of GBP1-Wt or by siRNA-mediated knockdown. Silencing of GBP1 impaired the release of viral particles and resulted in intracellular HCV core accumulation, while overexpression of GBP1 favored viral replication and release. CLSM and STED analyses revealed a vesicular distribution of GBP1 in the perinuclear region. Here, it colocalizes with HCV core around lipid droplets, where it acts as assembly platform and thereby favors HCV morphogenesis and release. Collectively, our results identify an unprecedented function of GBP1 as a pro-viral factor. As such, it is essential for viral assembly and release acting through tethering factors involved in HCV morphogenesis onto the surface of lipid droplets.

Antagonism of epidermal growth factor receptor signaling favors hepatitis E virus life cycle.

Hepatitis E virus (HEV) poses a global threat, which currently remains understudied in terms of host interactions. Epidermal growth factor receptor (EGFR) plays multifaceted roles in viral pathogenesis, impacting host-cell entry, viral replication, and host-defense modulation. On the one hand, EGFR signaling emerged as a major driver in innate immunity; on the other hand, a crosstalk between HEV and EGFR requires deeper analysis. We therefore aimed to dissect the receptor's involvement in the HEV life cycle. In persistently HEV-infected cells, the EGFR amount is decreased alongside with enhanced receptor internalization. As compared with the control ligand-induced EGFR, activation revealed an early receptor internalization and degradation in HEV-replicating cells, resulting in a notable EGFR signaling delay. Interestingly, inhibition or silencing of EGFR increased viral replication, extracellular and intracellular viral transcripts, and released infectious particles. The pro-viral impact of EGFR inhibition was attributed to (i) impaired expression of interferon-stimulated genes, (ii) activation of the autophagosomal system, (iii) virus-induced inhibition of lysosomal acidification, and (iv) a decrease of the cellular cholesterol level. IMPORTANCE: This study identifies epidermal growth factor receptor (EGFR) as a novel host factor affecting hepatitis E virus (HEV): EGFR downregulation promotes viral replication, release, and evasion from the innate immune response. The discovery that EGFR inhibition favors viral spread is particularly concerning for HEV patients undergoing EGFR inhibitor treatment.

The impact of HBx protein on mitochondrial dynamics and associated signaling pathways strongly depends on the hepatitis B virus genotype.

Chronic hepatitis B virus (HBV) infections are strongly associated with liver cirrhosis, inflammation, and hepatocellular carcinoma. In this context, the viral HBx protein is considered as a major factor influencing HBV-associated pathogenesis through deregulation of multiple cellular signaling pathways and is therefore a potential target for prognostic and therapeutic applications. However, HBV-associated pathogenesis differs significantly between genotypes, with the relevant factors and in particular the contribution of the genetic diversity of HBx being largely unknown. To address this question, we studied the specific genotype-dependent impact of HBx on cellular signaling pathways, focusing in particular on morphological and functional parameters of mitochondria. To exclusively investigate the impact of HBx of different genotypes on integrity and function of mitochondria in the absence of additional viral factors, we overexpressed HBx in Huh7 or HepG2 cells. Key signaling pathways were profiled by kinome analysis and correlated with expression levels of mitochondrial and pathogenic markers. Conclusively, HBx of genotypes A and G caused strong disruption of mitochondrial morphology alongside an induction of PTEN-induced putative kinase 1/Parkin-mediated mitophagy. These effects were only moderately dysregulated by genotypes B and E, whereas genotypes C and D exhibit an intermediate effect in this regard. Accordingly, changes in mitochondrial membrane potential and elevated reactive oxygen species production were associated with the HBx-mediated dysfunction among different genotypes. Also, genotype-related differences in mitophagy induction were identified and indicated that HBx-mediated changes in the mitochondria morphology and function strongly depend on the genotype. This indicates a relevant role of HBx in the process of genotype-dependent liver pathogenesis of HBV infections and reveals underlying mechanisms.IMPORTANCEThe hepatitis B virus is the main cause of chronic liver disease worldwide and differs in terms of pathogenesis and clinical outcome among the different genotypes. Furthermore, the viral HBx protein is a known factor in the progression of liver injury by inducing aberrant mitochondrial structures and functions. Consequently, the selective removal of dysfunctional mitochondria is essential to maintain overall cellular homeostasis and cell survival. Consistent with the intergenotypic difference of HBV, our data reveal significant differences regarding the impact of HBx of different genotypes on mitochondrial dynamic and function and thereby on radical oxygen stress levels within the cell. We subsequently observed that the induction of mitophagy differs significantly across the heterogenetic HBx proteins. Therefore, this study provides evidence that HBx-mediated changes in the mitochondria dynamics and functionality strongly depend on the genotype of HBx. This highlights an important contribution of HBx in the process of genotype-dependent liver pathogenesis.

Synthesis and structural characterization of new macrocyclic inhibitors of the Zika virus NS2B-NS3 protease.

Three new series of macrocyclic active site-directed inhibitors of the Zika virus (ZIKV) NS2B-NS3 protease were synthesized. First, attempts were made to replace the basic P3 lysine residue of our previously described inhibitors with uncharged and more hydrophobic residues. This provided numerous compounds with inhibition constants between 30 and 50 nM. A stronger reduction of the inhibitory potency was observed when the P2 lysine was replaced by neutral residues, all of these inhibitors possess Ki values >1 µM. However, it is possible to replace the P2 lysine with the less basic 3-aminomethylphenylalanine, which provides a similarly potent inhibitor of the ZIKV protease (Ki = 2.69 nM). Crystal structure investigations showed that the P2 benzylamine structure forms comparable interactions with the protease as lysine. Twelve additional structures of these inhibitors in complex with the protease were determined, which explain many, but not all, SAR data obtained in this study. All individual modifications in the P2 or P3 position resulted in inhibitors with low antiviral efficacy in cell culture. Therefore, a third inhibitor series with combined modifications was synthesized; all of them contain a more hydrophobic  d-cyclohexylalanine in the linker segment. At a concentration of 40 µM, two of these compounds possess similar antiviral potency as ribavirin at 100 µM. Due to their reliable crystallization in complex with the ZIKV protease, these cyclic compounds are very well suited for a rational structure-based development of improved inhibitors.

Pathogenetic mechanisms and therapeutic approaches of acute-to-chronic liver failure.

Liver cirrhosis is the end stage of all chronic liver diseases and contributes significantly to overall mortality of 2% globally. The age-standardized mortality from liver cirrhosis in Europe is between 10 and 20% and can be explained by not only the development of liver cancer but also the acute deterioration in the patient's overall condition. The development of complications including accumulation of fluid in the abdomen (ascites), bleeding in the gastrointestinal tract (variceal bleeding), bacterial infections, or a decrease in brain function (hepatic encephalopathy) define an acute decompensation that requires therapy and often leads to acute-on-chronic liver failure (ACLF) by different precipitating events. However, due to its complexity and organ-spanning nature, the pathogenesis of ACLF is poorly understood, and the common underlying mechanisms leading to the development of organ dysfunction or failure in ACLF are still elusive. Apart from general intensive care interventions, there are no specific therapy options for ACLF. Liver transplantation is often not possible in these patients due to contraindications and a lack of prioritization. In this review, we describe the framework of the ACLF-I project consortium funded by the Hessian Ministry of Higher Education, Research and the Arts (HMWK) based on existing findings and will provide answers to these open questions.

Catch Me if You Can: the Crosstalk of Zika Virus and the Restriction Factor Tetherin.

Zika virus (ZIKV) is a flavivirus that is mainly transmitted by Aedes mosquitos and normally causes mild symptoms. During the outbreak in the Americas in 2015, it was associated with more severe implications, like microcephaly in newborns and the Guillain-Barré syndrome. The lack of specific vaccines and cures strengthens the need for a deeper understanding of the virus life cycle and virus-host interactions. The restriction factor tetherin (THN) is an interferon-inducible cellular protein with broad antiviral properties. It is known to inhibit the release of various enveloped viruses by tethering them to each other and the cell membrane, thereby preventing their further spread. On the other hand, different viruses have developed various escape strategies against THN. Analysis of the cross-talk between ZIKV and THN revealed that, despite a strong induction of THN mRNA expression in ZIKV-infected cells, this is not reflected by an elevated protein level of THN. Contrariwise, the THN protein level is decreased due to a reduced half-life. The increased degradation of THN in ZIKV infected cells involves the endo-lysosomal system but does not depend on the early steps of autophagy. Enrichment of THN by depletion of the ESCRT-0 protein HRS diminishes ZIKV release and spread, which points out the capacity of THN to restrict ZIKV and explains the enhanced THN degradation in infected cells as an effective viral escape strategy. IMPORTANCE Although tetherin expression is strongly induced by ZIKV infection there is a reduction in the amount of tetherin protein. This is due to enhanced lysosomal degradation. However, if the tetherin level is rescued then the release of ZIKV is impaired. This shows that tetherin is a restriction factor for ZIKV, and the induction of an efficient degradation represents a viral escape strategy. To our knowledge, this is the first study that describes and characterizes tetherin as a restriction factor for the ZIKV life cycle.

Vaccine effectiveness against severe COVID-19 during the Omicron wave in Germany: results from the COViK study.

PURPOSE: COViK, a prospective hospital-based multicenter case-control study in Germany, aims to assess the effectiveness of COVID-19 vaccines against severe disease. Here, we report vaccine effectiveness (VE) against COVID-19-caused hospitalization and intensive care treatment during the Omicron wave. METHODS: We analyzed data from 276 cases with COVID-19 and 494 control patients recruited in 13 hospitals from 1 December 2021 to 5 September 2022. We calculated crude and confounder-adjusted VE estimates. RESULTS: 21% of cases (57/276) were not vaccinated, compared to 5% of controls (26/494; p < 0.001). Confounder-adjusted VE against COVID-19-caused hospitalization was 55.4% (95% CI: 12-78%), 81.5% (95% CI: 68-90%) and 95.6% (95%CI: 88-99%) after two, three and four vaccine doses, respectively. VE against hospitalization due to COVID-19 remained stable up to one year after three vaccine doses. CONCLUSION: Three vaccine doses remained highly effective in preventing severe disease and this protection was sustained; a fourth dose further increased protection.

Relevance of HBx for Hepatitis B Virus-Associated Pathogenesis.

The hepatitis B virus (HBV) counts as a major global health problem, as it presents a significant causative factor for liver-related morbidity and mortality. The development of hepatocellular carcinomas (HCC) as a characteristic of a persistent, chronic infection could be caused, among others, by the pleiotropic function of the viral regulatory protein HBx. The latter is known to modulate an onset of cellular and viral signaling processes with emerging influence in liver pathogenesis. However, the flexible and multifunctional nature of HBx impedes the fundamental understanding of related mechanisms and the development of associated diseases, and has even led to partial controversial results in the past. Based on the cellular distribution of HBx-nuclear-, cytoplasmic- or mitochondria-associated-this review encompasses the current knowledge and previous investigations of HBx in context of cellular signaling pathways and HBV-associated pathogenesis. In addition, particular focus is set on the clinical relevance and potential novel therapeutic applications in the context of HBx.

The Epidermal Growth Factor Receptor Is a Relevant Host Factor in the Early Stages of The Zika Virus Life Cycle In Vitro.

Zika virus (ZIKV) is a flavivirus that is well known for the epidemic in the Americas in 2015 and 2016 in which microcephaly in newborns and other neurological complications were connected to ZIKV infection. Many aspects of the ZIKV viral life cycle, including binding and entry into the host cell, are still enigmatic. Based on the observation that CHO cells lack expression of the epidermal growth factor receptor (EGFR) and are not permissive for various ZIKV strains, the relevance of EGFR for the viral life cycle was analyzed. Infection of A549 cells by ZIKV leads to a rapid internalization of EGFR that colocalizes with the endosomal marker EEA1. Moreover, infection by different ZIKV strains is associated with an activation of EGFR and the subsequent activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling cascade. However, treatment of the cells with methyl-ß-cyclodextrin (MßCD), which on the one hand leads to an activation of EGFR but on the other hand prevents EGFR internalization, impairs ZIKV infection. Specific inhibition of EGFR or of the Ras-Raf-MEK-ERK signal transduction cascade hinders ZIKV infection by inhibition of ZIKV entry. In accordance with this, knockout of EGFR expression impedes ZIKV entry. In the case of an already established infection, inhibition of EGFR or of downstream signaling does not affect viral replication. Taken together, these data demonstrate the relevance of EGFR in the early stages of ZIKV infection and identify EGFR as a target for antiviral strategies. IMPORTANCE These data deepen the knowledge about the ZIKV infection process and demonstrate the relevance of EGFR for ZIKV entry. In light of the fact that a variety of specific and efficient inhibitors of EGFR and of EGFR-dependent signaling have been developed and licensed, repurposing of these substances could be a helpful tool to prevent the spreading of ZIKV infection in an epidemic outbreak.

Identification of the interferon-inducible GTPase GBP1 as major restriction factor for the Hepatitis E virus.

This study aims to gain deeper insight into HEV-induced innate immunity by characterizing the crosstalk between the virus and the host factor guanylate-binding protein 1 (GBP1). We observe that the amount of GBP1 is elevated upon infection, although number of transcripts is decreased, which is explained by a prolonged protein half-life. Modulation of GBP1 levels via overexpression significantly inhibits the viral life cycle. Use of various GBP-1 mutants revealed that the antiviral effect of GBP-1 on HEV is independent from the GTPase-activity, but depends on the capacity of GBP-1 to form GBP1 homodimers. This connects GBP-1 to the autophagosomal pathway. Indeed, dimerization competent GBP1 targets the viral capsid protein to the lysosomal compartment leading to inactivation of the viral particle. Most importantly, silencing of GBP1 abolishes the antiviral effect of IFNγ on HEV. In IFNγ treated cells the virus is targeted to lysosomal structures and destroyed therein. This process depends in part on GBP1. These observations about the relevance of GBP1 for type II interferon-mediated innate immunity against HEV could be a base for tailoring novel antivirals and improvement of disease management.IMPORTANCE Although HEV represents a worldwide public health problem with 20 million infections and 44.000 death cases per year, there are still no specific antivirals available and many aspects of the viral life cycle are not well understood. Here we identify the guanylate binding protein 1 (GBP1) as a restriction factor affecting life cycle of HEV. Surprisingly, the antiviral effect of GBP1 does not depend on its GTPase function, but on its capacity to homodimerize. We revealed that GBP1 exerts its antiviral activity by targeting HEV to the lysosomal compartment where the virus is inactivated. Most importantly, we observed that the antiviral effect of interferon-γ on HEV strongly depends on GBP1. Our observation that GBP1 impairs HEV and is crucial for the antiviral effect of interferons on HEV extends understanding of host defense-mechanisms. As the interferon-system represents a universal defense-mechanism, our study could help to design novel antivirals targeting.

Regulatory concepts to guide and promote the accelerated but safe clinical development and licensure of COVID-19 vaccines in Europe.

The ongoing COVID-19 pandemic caused by the SARS-CoV-2 coronavirus has affected the health of tens of millions of people worldwide. In particular, in elderly and frail individuals the infection can lead to severe disease and even fatal outcomes. Although the pandemic is primarily a human health crisis its consequences are much broader with a tremendous impact on global economics and social systems. Vaccines are considered the most powerful measure to fight the pandemic and protect people from COVID-19. Based on the concerted activities of scientists, manufacturers and regulators, the urgent need for effective countermeasures has provoked the development and licensure of novel COVID-19 vaccines in an unprecedentedly fast and flexible manner within <1 year. To ensure the safety and efficacy of these novel vaccines during the clinical development and the routine use in post-licensure vaccination campaigns existing regulatory requirements and procedures had to be wisely and carefully adapted to allow for an expedited evaluation without compromising the thoroughness of the regulatory and scientific assessment. In this review, we describe the regulatory procedures, concepts and requirements applied to guide and promote the highly accelerated development and licensure of safe and efficacious COVID-19 vaccines in Europe.

Persistence of infectious SARS-CoV-2 particles for up to 37 days in patients with mild COVID-19.

BACKGROUND: People suffering from COVID-19 are typically considered non-infectious 14 days after diagnosis if symptoms have disappeared for at least 48 h. We describe three patients who independently acquired their infection. These three patients experienced mild COVID-19 and completely recovered symptomatically within 10 days, but remained PCR-positive in deep pharyngeal samples for at least 38 days. We attempted to isolate virus from pharyngeal swabs to investigate whether these patients still carried infectious virus. METHODS: Infectious virus was amplified in Vero E6 cells and characterized by electron microscopy and WGS. The immune response was investigated by ELISA and peptide arrays. RESULTS: In all three cases, infectious and replication-competent virus was isolated and amplified in Vero E6 cells. Virus replication was detected by RT-PCR and immunofluorescence microscopy. Electron microscopy confirmed the formation of intact SARS-CoV-2 particles. For a more detailed analysis, all three isolates were characterized by whole-genome sequencing (WGS). The sequence data revealed that the isolates belonged to the 20A or 20C clade, and two mutations in ORF8 were identified among other mutations that could be relevant for establishing a long-term infection. Characterization of the humoral immune response in comparison to patients that had fully recovered from mild COVID-19 revealed a lack of antibodies binding to sequential epitopes of the receptor-binding domain (RBD) for the long-term infected patients. CONCLUSION: Thus, a small portion of COVID-19 patients displays long-term infectivity and termination of quarantine periods after 14 days, without PCR-based testing, should be reconsidered critically.

Analysis of BNT162b2- and CVnCoV-elicited sera and of convalescent sera toward SARS-CoV-2 viruses.

BACKGROUND: The mRNA vaccine BNT162b2 (Comirnaty, BioNTech/Pfizer) and the vaccine candidate CVnCoV (Curevac) each encode a stabilized spike protein of SARS-CoV2 as antigen but differ with respect to the nature of the mRNA (modified versus unmodified nucleotides) and the mRNA amount (30 µg versus 12 µg RNA). This study characterizes antisera elicited by these two vaccines in comparison to convalescent sera. METHODS: Sera from BNT162b2 vaccinated healthcare workers, and sera from participants of a phase I trial vaccinated with 2, 4, 6, 8, or 12 µg CVnCoV and convalescent sera from hospitalized patients were analyzed by ELISA, neutralization tests, surface plasmon resonance (SPR), and peptide arrays. RESULTS: BNT162b2-elicited sera and convalescent sera have a higher titer of spike-RBD-specific antibodies and neutralizing antibodies as compared to the CVnCoV-elicited sera. For all analyzed sera a reduction in binding and neutralizing antibodies was found for the lineage B.1.351 variant of concern. SPR analyses revealed that the CVnCoV-elicited sera have a lower fraction of slow-dissociating antibodies. Accordingly, the CVnCoV sera almost fail to compete with the spike-ACE2 interaction. The significance of common VOC mutations K417N, E484K, or N501Y focused on linear epitopes was analyzed using a peptide array approach. The peptide arrays showed a strong difference between convalescent sera and vaccine-elicited sera. Specifically, the linear epitope at position N501 was affected by the mutation and elucidates the escape of viral variants to antibodies against this linear epitope. CONCLUSION: These data reveal differences in titer, neutralizing capacity, and affinity of the antibodies between BNT162b2- and CVnCoV-elicited sera, which could contribute to the apparent differences in vaccine efficacy.

Hepatitis E virus egress and beyond - the manifold roles of the viral ORF3 protein.

Although the hepatitis E virus represents an uprising threat to the global community by representing the commonest cause of an acute viral hepatitis worldwide, its life cycle is grossly understudied. Albeit HEV is a non-enveloped virus, its progeny is released as quasi-enveloped virions. Thus, the responsible accessory protein pORF3 gained rising attention in the past years. It mediates viral release via the exosomal route by targeting the viral capsid to the endosomal system, more precisely to multivesicular bodies. As this is followed by quasi-envelopment, pORF3 may in terms represent a substitute to a conventional envelope protein. This feature proofs to be rather unique with respect to other enteric viruses, although the protein's role in the viral life cycle seems to reach far beyond simply maintaining release of progeny viruses. How pORF3 affects viral morphogenesis, how it mediates efficient viral release and how it supports viral spread is summarised in this microreview. With this, we aim to shed light on functions of pORF3 to gain further insights in still enigmatic aspects of the HEV life cycle. TAKE AWAYS: HEV is released as exosome via multivesicular bodies Viral pORF3 mediates release via endosomal complexes required for transport pORF3 modulates various cellular processes in infected cells Elucidation of pORF3-related processes imply novel clinical strategies.

[Overview of COVID-19 vaccines licensed in the EU-from technology via clinical trial to registration]. / Übersicht über die in der EU zugelassenen COVID-19-Impfstoffe ­ von der Technologie über die klinische Prüfung zur Zulassung.

Currently (as of July 2022), six different COVID-19 vaccines are licensed in the EU. These include two mRNA-based vaccines (BNT162b2, Comirnaty® and mRNA-1273, Spikevax®), two adenoviral vector-based vaccines (AZD1222, Vaxzevria® and Ad26.COV2.S, Jcovden®), the subunit vaccine Nuvaxovid® (NVX-CoV2373), and the inactivated virus vaccine VLA2001. Although these vaccines are based on different technologies, they all share the use of the spike protein of SARS-CoV­2 as antigen.This overview describes the characteristics of their composition, their efficacy, and the impact of various factors on efficacy. Another aspect of this overview is the description of the approval process and the identification of factors that have contributed to the unprecedented speed in the development and approval of vaccines against a pandemic pathogen.

[Hepatitis B and C: mechanisms of virus-induced liver pathogenesis and tumorigenesis]. / Hepatitis B und C: Mechanismen der virusinduzierten Leberpathogenese und Tumorentstehung.

Worldwide, the hepatitis B and hepatitis C viruses (HBV, HCV) are the most relevant causative viral agents of a chronic hepatitis (inflammation of the liver). At present, more than 250 million people suffer from a chronic HBV infection globally, resulting in 0.8 million deaths per year. A chronic HCV infection accounts for about 70 million cases worldwide, leading to a death toll of about 1 million per year. An approved vaccine is only available against an HBV infection. Both HBV and HCV infections result in a highly increased risk of developing liver fibrosis, cirrhosis, and a hepatocellular carcinoma (HCC).This review aims to describe mechanisms of the HBV- and HCV-associated pathogenesis. The focus is on the interplay between a chronic infection with intracellular signaling transduction, metabolic pathways with an emphasis on lipid metabolism, the establishment of liver fibrosis and cirrhosis during a chronic infection, and the mechanisms of the onset of a virally induced HCC.Despite there being great advances in the characterization of viral life cycles and the development of robust antiviral strategies, significant hurdles persist: gaining a better understanding of the mechanisms that drive virus-associated pathogenesis as well as increasing insights regarding different viral genotypes having impacts on alternate pathogeneses.

[Viral hepatitis A to E: prevalence, pathogen characteristics, and pathogenesis]. / Die Virushepatitiden A bis E: Prävalenz, Erregermerkmale und Pathogenese.

Viral hepatitis is characterized as an acute or chronic inflammation of the liver induced by an infection with certain viruses. At present, around 325 million humans suffer from the chronic form of the disease worldwide. Each year, about 1.6 million people die as a result of viral hepatitis. The causative agents, hepatitis viruses, are subdivided into five groups of pathogens, which are denoted with the letters A to E (HAV to HEV). These differ from each other with respect to phylogeny, transmission, epidemiology, host-specificity, life cycle, structure, and distinct aspects of pathogenesis.The strictly human-pathogenic HAV, a member of the Picornaviridae family, mostly induces acute hepatitis and displays a dominant spread over the Global South. The Hepeviridae-affiliated HEV shows a similar epidemiology, yet spreads further into industrialized countries due to its zoonotic potential. Furthermore, HEV is defined by the capability of inducing chronic hepatitis. This course of disease is also found in a more pronounced manner for the globally prevalent HBV (Hepadnaviridae) and its satellite virus HDV (Kolmioviridae), which further increases their carcinogenic potential. Lastly, a worldwide distribution is similarly described for HCV (Flaviviridae), which displays a high risk of chronifications and therefore a highly increased carcinogenic potential.The aforementioned pathogens differ with respect to their properties and life cycles. Thus, a differentiated look on epidemiology, diagnostic procedures, and disease prevention is required. Despite the presence of therapies, in some cases even a vaccine, there is an urgent need for advances in research on these aspects, especially for poverty-related pathogens.

[Batch testing as an essential pillar of the supply of safe and effective vaccines]. / Chargenprüfung als wesentliche Säule der Versorgung mit sicheren und wirksamen Impfstoffen.

The Paul-Ehrlich Institute (PEI) plays a central role in the release of vaccines in Germany as well as Europe. The experimental testing and release of each vaccine batch is carried out according to the procedures and regulations of the Official Control Authority Batch Release (OCABR) and the German medicine act paragraph 32. The independent testing aims to demonstrate the conformity of quality criteria set in the marketing authorization for each lot produced. This article illustrates both the batch release procedure in general and specifically for the newly developed and approved COVID-19 vaccines during the COVID-19 pandemic.

Not uncommon: HBV genotype G co-infections among healthy European HBV carriers with genotype A and E infection.

BACKGROUND & AIMS: HBV genotype G (HBV/G) is mainly found in co-infections with other HBV genotypes and was identified as an independent risk factor for liver fibrosis. This study aimed to analyse the prevalence of HBV/G co-infections in healthy European HBV carriers and to characterize the crosstalk of HBV/G with other genotypes. METHODS: A total of 560 European HBV carriers were tested via HBV/G-specific PCR for HBV/G co-infections. Quasispecies distribution was analysed via deep sequencing, and the clinical phenotype was characterized regarding qHBsAg-/HBV-DNA levels and frequent mutations. Replicative capacity and expression of HBsAg/core was studied in hepatoma cells co-expressing HBV/G with either HBV/A, HBV/D or HBV/E using bicistronic vectors. RESULTS: Although no HBV/G co-infection was found by routine genotyping PCR, HBV/G was detected by specific PCR in 4%-8% of patients infected with either HBV/A or HBV/E but only infrequently in other genotypes. In contrast to HBV/E, HBV/G was found as the quasispecies major variant in co-infections with HBV/A. No differences in the clinical phenotype were observed for HBV/G co-infections. In vitro RNA and DNA levels were comparable among all genotypes, but expression and release of HBsAg was reduced in co-expression of HBV/G with HBV/E. In co-expression with HBV/A and HBV/E expression of HBV/G-specific core was enhanced while core expression from the corresponding genotype was markedly diminished. CONCLUSIONS: HBV/G co-infections are common in European inactive carriers with HBV/A and HBV/E infection, but sufficient detection depends strongly on the assay. HBV/G regulated core expression might play a critical role for survival of HBV/G in co-infections.

[Licensing procedures for human vaccines in Germany and Europe and the WHO prequalification program]. / Zulassungsverfahren für Humanimpfstoffe in Deutschland und Europa und das Präqualifizierungsprogramm der WHO.

Vaccinations are amongst the most important and powerful preventive measures modern medicine has to offer. By their nature, vaccines represent a very complex class of biological medicines. Licensure of novel vaccines is a process conducted on the basis of a comprehensive set of well-defined legal and procedural requirements. The key aim of the regulatory evaluation of vaccines is to confirm their pharmaceutical quality, safety, and efficacy in order to conclude on the positive benefit/risk ratio that is an absolute prerequisite for granting a license.In Europe there exist four types of licensing procedures for human vaccines (national, MRP, DCP, and centralized) depending on whether the vaccine is intended to be marketed nationally, in several, or all EU countries. Modern innovative vaccines are mostly licensed via the centralized EU procedure, which also offers a certain degree of procedural flexibility for specific vaccines under defined conditions. However, the basic regulatory requirements are the same for all types of licensing procedures. In order for a license to be granted, a vaccine has to fulfill all relevant regulatory requirements as regards pharmaceutical quality, including each manufacturing and control step as well as preclinical and clinical characterization. Most importantly, clinical trials in humans conducted prelicensure to determine vaccine safety and efficacy play a key role during the licensing procedure and for decision making.The WHO prequalification procedure was implemented to enable worldwide access to medicines of approved quality. Its prime aim is to establish and ensure appropriate universally recognized regulatory standards for vaccines to be used throughout the entire world.