RESUMO
Effector CD8(+) T cells (CD8 TE) play a key role during hepatotropic viral infections. Here, we used advanced imaging in mouse models of hepatitis B virus (HBV) pathogenesis to understand the mechanisms whereby these cells home to the liver, recognize antigens, and deploy effector functions. We show that circulating CD8 TE arrest within liver sinusoids by docking onto platelets previously adhered to sinusoidal hyaluronan via CD44. After the initial arrest, CD8 TE actively crawl along liver sinusoids and probe sub-sinusoidal hepatocytes for the presence of antigens by extending cytoplasmic protrusions through endothelial fenestrae. Hepatocellular antigen recognition triggers effector functions in a diapedesis-independent manner and is inhibited by the processes of sinusoidal defenestration and capillarization that characterize liver fibrosis. These findings reveal the dynamic behavior whereby CD8 TE control hepatotropic pathogens and suggest how liver fibrosis might reduce CD8 TE immune surveillance toward infected or transformed hepatocytes.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Vírus da Hepatite B/fisiologia , Hepatite B/imunologia , Fígado/imunologia , Monitorização Imunológica , Animais , Movimento Celular , Células Endoteliais/metabolismo , Hepatite B/patologia , Hepatócitos/metabolismo , Ácido Hialurônico/metabolismo , Fígado/citologia , Cirrose Hepática , Camundongos , Camundongos Endogâmicos C57BL , Adesividade Plaquetária , Organismos Livres de Patógenos EspecíficosRESUMO
Chronic hepatitis B virus (HBV) infection affects 300 million patients worldwide1,2, in whom virus-specific CD8 T cells by still ill-defined mechanisms lose their function and cannot eliminate HBV-infected hepatocytes3-7. Here we demonstrate that a liver immune rheostat renders virus-specific CD8 T cells refractory to activation and leads to their loss of effector functions. In preclinical models of persistent infection with hepatotropic viruses such as HBV, dysfunctional virus-specific CXCR6+ CD8 T cells accumulated in the liver and, as a characteristic hallmark, showed enhanced transcriptional activity of cAMP-responsive element modulator (CREM) distinct from T cell exhaustion. In patients with chronic hepatitis B, circulating and intrahepatic HBV-specific CXCR6+ CD8 T cells with enhanced CREM expression and transcriptional activity were detected at a frequency of 12-22% of HBV-specific CD8 T cells. Knocking out the inhibitory CREM/ICER isoform in T cells, however, failed to rescue T cell immunity. This indicates that CREM activity was a consequence, rather than the cause, of loss in T cell function, further supported by the observation of enhanced phosphorylation of protein kinase A (PKA) which is upstream of CREM. Indeed, we found that enhanced cAMP-PKA-signalling from increased T cell adenylyl cyclase activity augmented CREM activity and curbed T cell activation and effector function in persistent hepatic infection. Mechanistically, CD8 T cells recognizing their antigen on hepatocytes established close and extensive contact with liver sinusoidal endothelial cells, thereby enhancing adenylyl cyclase-cAMP-PKA signalling in T cells. In these hepatic CD8 T cells, which recognize their antigen on hepatocytes, phosphorylation of key signalling kinases of the T cell receptor signalling pathway was impaired, which rendered them refractory to activation. Thus, close contact with liver sinusoidal endothelial cells curbs the activation and effector function of HBV-specific CD8 T cells that target hepatocytes expressing viral antigens by means of the adenylyl cyclase-cAMP-PKA axis in an immune rheostat-like fashion.
Assuntos
Linfócitos T CD8-Positivos , Hepatite B Crônica , Fígado , Animais , Humanos , Masculino , Camundongos , Linfócitos T CD8-Positivos/enzimologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Modulador de Elemento de Resposta do AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Vírus da Hepatite B/imunologia , Hepatite B Crônica/imunologia , Hepatite B Crônica/virologia , Hepatócitos/imunologia , Hepatócitos/virologia , Fígado/imunologia , Fígado/virologia , Fosforilação , Transdução de Sinais , Ativação LinfocitáriaRESUMO
The emergence and global spread of SARS-CoV-2 has resulted in the urgent need for an in-depth understanding of molecular functions of viral proteins and their interactions with the host proteome. Several individual omics studies have extended our knowledge of COVID-19 pathophysiology1-10. Integration of such datasets to obtain a holistic view of virus-host interactions and to define the pathogenic properties of SARS-CoV-2 is limited by the heterogeneity of the experimental systems. Here we report a concurrent multi-omics study of SARS-CoV-2 and SARS-CoV. Using state-of-the-art proteomics, we profiled the interactomes of both viruses, as well as their influence on the transcriptome, proteome, ubiquitinome and phosphoproteome of a lung-derived human cell line. Projecting these data onto the global network of cellular interactions revealed crosstalk between the perturbations taking place upon infection with SARS-CoV-2 and SARS-CoV at different levels and enabled identification of distinct and common molecular mechanisms of these closely related coronaviruses. The TGF-ß pathway, known for its involvement in tissue fibrosis, was specifically dysregulated by SARS-CoV-2 ORF8 and autophagy was specifically dysregulated by SARS-CoV-2 ORF3. The extensive dataset (available at https://covinet.innatelab.org ) highlights many hotspots that could be targeted by existing drugs and may be used to guide rational design of virus- and host-directed therapies, which we exemplify by identifying inhibitors of kinases and matrix metalloproteases with potent antiviral effects against SARS-CoV-2.
Assuntos
COVID-19/metabolismo , Interações Hospedeiro-Patógeno , Proteoma/metabolismo , Proteômica , SARS-CoV-2/patogenicidade , Síndrome Respiratória Aguda Grave/metabolismo , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/patogenicidade , Animais , Antivirais/farmacologia , Autofagia/efeitos dos fármacos , COVID-19/imunologia , COVID-19/virologia , Linhagem Celular , Conjuntos de Dados como Assunto , Avaliação Pré-Clínica de Medicamentos , Interações Hospedeiro-Patógeno/imunologia , Humanos , Inibidores de Metaloproteinases de Matriz/farmacologia , Fosforilação , Mapas de Interação de Proteínas , Inibidores de Proteínas Quinases/farmacologia , Processamento de Proteína Pós-Traducional , Proteoma/química , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia , SARS-CoV-2/imunologia , Síndrome Respiratória Aguda Grave/imunologia , Síndrome Respiratória Aguda Grave/virologia , Fator de Crescimento Transformador beta/metabolismo , Ubiquitinação , Proteínas Virais/química , Proteínas Virais/metabolismo , Proteínas Viroporinas/metabolismoRESUMO
Chronic infection is difficult to overcome because of exhaustion or depletion of cytotoxic effector CD8(+) T cells (cytotoxic T lymphoytes (CTLs)). Here we report that signaling via Toll-like receptors (TLRs) induced intrahepatic aggregates of myeloid cells that enabled the population expansion of CTLs (iMATEs: 'intrahepatic myeloid-cell aggregates for T cell population expansion') without causing immunopathology. In the liver, CTL proliferation was restricted to iMATEs that were composed of inflammatory monocyte-derived CD11b(+) cells. Signaling via tumor-necrosis factor (TNF) caused iMATE formation that facilitated costimulation dependent on the receptor OX40 for expansion of the CTL population. The iMATEs arose during acute viral infection but were absent during chronic viral infection, yet they were still induced by TLR signaling. Such hepatic expansion of the CTL population controlled chronic viral infection of the liver after vaccination with DNA. Thus, iMATEs are dynamic structures that overcome regulatory cues that limit the population expansion of CTLs during chronic infection and can be used in new therapeutic vaccination strategies.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Proliferação de Células , Hepatopatias/imunologia , Coriomeningite Linfocítica/imunologia , Células Mieloides/imunologia , Linfócitos T Citotóxicos/imunologia , Animais , Animais Recém-Nascidos , Antígeno CD11b/imunologia , Antígeno CD11b/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Doença Crônica , Citometria de Fluxo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Imunoterapia , Fígado/imunologia , Fígado/metabolismo , Fígado/virologia , Hepatopatias/terapia , Hepatopatias/virologia , Coriomeningite Linfocítica/terapia , Coriomeningite Linfocítica/virologia , Vírus da Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Microscopia Confocal , Células Mieloides/metabolismo , Receptores OX40/imunologia , Receptores OX40/metabolismo , Transdução de Sinais/imunologia , Linfócitos T Citotóxicos/metabolismo , Receptor Toll-Like 9/imunologia , Receptor Toll-Like 9/metabolismoRESUMO
Since its discovery in 1965, our understanding of the hepatitis B virus (HBV) replication cycle and host immune responses has increased markedly. In contrast, our knowledge of the molecular biology of hepatitis delta virus (HDV), which is associated with more severe liver disease, is less well understood. Despite the progress made, critical gaps remain in our knowledge of HBV and HDV replication and the mechanisms underlying viral persistence and evasion of host immunity. The International HBV Meeting is the leading annual scientific meeting for presenting the latest advances in HBV and HDV molecular virology, immunology, and epidemiology. In 2023, the annual scientific meeting was held in Kobe, Japan and this review summarises some of the advances presented at the Meeting and lists gaps in our knowledge that may facilitate the development of new therapies.
Assuntos
Vírus da Hepatite B , Hepatite B , Vírus Delta da Hepatite , Replicação Viral , Vírus da Hepatite B/genética , Vírus da Hepatite B/fisiologia , Vírus da Hepatite B/imunologia , Humanos , Vírus Delta da Hepatite/genética , Vírus Delta da Hepatite/fisiologia , Hepatite B/virologia , Hepatite B/imunologia , Biologia Molecular , Japão , Hepatite D/virologia , Interações Hospedeiro-Patógeno/imunologia , Interações Hospedeiro-Patógeno/genéticaRESUMO
Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), serving as the viral persistence form and transcription template of HBV infection, hijacks host histone and non-histone proteins to form a minichromosome and utilizes posttranslational modifications (PTMs) "histone code" for its transcriptional regulation. HBV X protein (HBx) is known as a cccDNA transcription activator. In this study we established a dual system of the inducible reporter cell lines modelling infection with wildtype (wt) and HBx-null HBV, both secreting HA-tagged HBeAg as a semi-quantitative marker for cccDNA transcription. The cccDNA-bound histone PTM profiling of wt and HBx-null systems, using chromatin immunoprecipitation coupled with quantitative PCR (ChIP-qPCR), confirmed that HBx is essential for maintenance of cccDNA at transcriptionally active state, characterized by active histone PTM markers. Differential proteomics analysis of cccDNA minichromosome established in wt and HBx-null HBV cell lines revealed group-specific hits. One of the hits in HBx-deficient condition was a non-histone host DNA-binding protein high mobility group box 1 (HMGB1). Its elevated association to HBx-null cccDNA was validated by ChIP-qPCR assay in both the HBV stable cell lines and infection systems in vitro. Furthermore, experimental downregulation of HMGB1 in HBx-null HBV inducible and infection models resulted in transcriptional re-activation of the cccDNA minichromosome, accompanied by a switch of the cccDNA-associated histones to euchromatic state with activating histone PTMs landscape and subsequent upregulation of cccDNA transcription. Mechanistically, HBx interacts with HMGB1 and prevents its binding to cccDNA without affecting the steady state level of HMGB1. Taken together, our results suggest that HMGB1 is a novel host restriction factor of HBV cccDNA with epigenetic silencing mechanism, which can be counteracted by viral transcription activator HBx.
Assuntos
Proteína HMGB1 , Hepatite B , DNA Circular/genética , DNA Circular/metabolismo , DNA Viral/genética , DNA Viral/metabolismo , Epigênese Genética , Proteína HMGB1/genética , Células Hep G2 , Vírus da Hepatite B/metabolismo , Histonas/metabolismo , Humanos , Transativadores , Fatores de Transcrição/metabolismo , Proteínas Virais Reguladoras e Acessórias , Replicação Viral/genéticaRESUMO
This longitudinal prospective controlled multicenter study aimed to monitor immunity generated by three exposures caused by breakthrough infections (BTI) after COVID-19-vaccination considering pre-existing cell-mediated immunity to common-corona-viruses (CoV) which may impact cellular reactivity against SARS-CoV-2. Anti-SARS-CoV-2-spike-IgG antibodies (anti-S-IgG) and cellular reactivity against Spike-(S)- and nucleocapsid-(N)-proteins were determined in fully-vaccinated (F) individuals who either experienced BTI (F+BTI) or had booster vaccination (F+Booster) compared to partially vaccinated (P+BTI) and unvaccinated (U) from 1 to 24 weeks post PCR-confirmed infection. High avidity anti-S-IgG were found in F+BTI compared to U, the latter exhibiting increased long-lasting pro-inflammatory cytokines to S-stimulation. CoV was associated with higher cellular reactivity in U, whereas no association was seen in F. The study illustrates the induction of significant S-specific cellular responses in F+BTI building-up basic immunity by three exposures. Only U seem to benefit from pre-existing CoV immunity but demonstrated inflammatory immune responses compared to F+BTI who immunologically benefit from enhanced humoral and cellular immunity after BTI. This study demonstrates that individuals with hybrid immunity from COVID-19-vaccination and BTI acquire a stable humoral and cellular immune response that is maintained for at least 6 months. Our findings corroborate recommendations by health authorities to build on basic immunity by three S-protein exposures.
Assuntos
Anticorpos Antivirais , Vacinas contra COVID-19 , COVID-19 , Imunidade Celular , Glicoproteína da Espícula de Coronavírus , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vacina de mRNA-1273 contra 2019-nCoV/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Vacina BNT162/imunologia , Vacina BNT162/administração & dosagem , Infecções Irruptivas/imunologia , Infecções Irruptivas/prevenção & controle , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/administração & dosagem , Citocinas/imunologia , Imunização Secundária , Imunoglobulina G/sangue , Estudos Longitudinais , Fosfoproteínas/imunologia , Estudos Prospectivos , Glicoproteína da Espícula de Coronavírus/imunologia , VacinaçãoRESUMO
BACKGROUND: Infection with the Epstein-Barr virus (EBV) elicits a complex T-cell response against a broad range of viral proteins. Hence, identifying potential differences in the cellular immune response of patients with different EBV-associated diseases or different courses of the same disorder requires interrogation of a maximum number of EBV antigens. Here, we tested three novel EBV-derived antigen formulations for their ability to reactivate virus-specific T cells ex vivo in patients with EBV-associated infectious mononucleosis (IM). METHODS: We comparatively analyzed EBV-specific CD4+ and CD8+ T-cell responses to three EBV-derived antigen formulations in 20 pediatric patients during the early phase of IM: T-activated EBV proteins (BZLF1, EBNA3A) and EBV-like particles (EB-VLP), both able to induce CD4+ and CD8+ T-cell responses ex vivo, as well as an EBV-derived peptide pool (PP) covering 94 well-characterized CD8+ T-cell epitopes. We assessed the specificity, magnitude, kinetics, and functional characteristics of EBV-specific immune responses at two sequential time points (v1 and v2) within the first six weeks after IM symptom onset (Tonset). RESULTS: All three tested EBV-derived antigen formulations enabled the detection of EBV-reactive T cells during the early phase of IM without prior T-cell expansion in vitro. EBV-reactive CD4+ and CD8+ T cells were mainly mono-functional (CD4+: mean 64.92%, range 56.15-71.71%; CD8+: mean 58.55%, range 11.79-85.22%) within the first two weeks after symptom onset (v1) with IFN-γ and TNF-secreting cells representing the majority of mono-functional EBV-reactive T cells. By contrast, PP-reactive CD8+ T cells were primarily bi-functional (>60% at v1 and v2), produced IFN-γ and TNF and had more tri-functional than mono-functional components. We observed a moderate correlation between viral load and EBNA3A, EB-VLP, and PP-reactive CD8+ T cells (rs = 0.345, 0.418, and 0.356, respectively) within the first two weeks after Tonset, but no correlation with the number of detectable EBV-reactive CD4+ T cells. CONCLUSIONS: All three EBV-derived antigen formulations represent innovative and generic recall antigens suitable for monitoring EBV-specific T-cell responses ex vivo. Their combined use facilitates a thorough analysis of EBV-specific T-cell immunity and allows the identification of functional T-cell signatures linked to disease development and severity.
Assuntos
Antígenos Virais , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Herpesvirus Humano 4 , Mononucleose Infecciosa , Humanos , Mononucleose Infecciosa/imunologia , Mononucleose Infecciosa/virologia , Antígenos Virais/imunologia , Herpesvirus Humano 4/imunologia , Criança , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD4-Positivos/imunologia , Feminino , Masculino , Adolescente , Pré-Escolar , Epitopos de Linfócito T/imunologiaRESUMO
Outbreaks of emerging diseases, like Mpox in 2022, pose unprecedented challenges to global healthcare systems. Although Mpox cases globally decreased since the end of 2022, numbers are still significant in the African Region, European Region, Region of the Americas, and Western Pacific Region. Rapid and efficient detection of infected individuals by precise screening assays is crucial for successful containment. In these assays, analytical and clinical performance must be assessed to ensure high quality. However, clinical studies evaluating Mpox virus (MPXV) detection kits using patient-derived samples are scarce. This study evaluated the analytical and clinical performance of a new diagnostic MPXV real-time PCR detection kit (Sansure Monkeypox Virus Nucleic Acid Diagnostic Kit) using patient-derived samples collected in Germany during the MPXV clade IIb outbreak in 2022. Our experimental approach determined the Limit of Detection (LoD) to less than 200 cp/mL using whole blood samples and samples derived from vesicles or pustules. Furthermore, we tested potentially inhibiting substances and pathogens with homologous nucleic acid sequences or similar clinical presentation and detected no cross-reactivity or interference. Following this, the assay was compared to a CE-marked test in a clinical performance study and achieved a diagnostic sensitivity of 100.00% and diagnostic specificity of 96.97%. In summary, the investigated real-time PCR assay demonstrates high analytical performance and concurs with the competitor device with high specificity and sensitivity.
Assuntos
Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e Especificidade , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Alemanha/epidemiologia , Mpox/diagnóstico , Mpox/virologia , Kit de Reagentes para Diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Limite de Detecção , Surtos de Doenças , Parapoxvirus/isolamento & purificação , Parapoxvirus/genéticaRESUMO
OBJECTIVES: A major goal of curative hepatitis B virus (HBV) treatments is the reduction or inactivation of intrahepatic viral covalently closed circular DNA (cccDNA). Hence, precise cccDNA quantification is essential in preclinical and clinical studies. Southern blot (SB) permits cccDNA visualisation but lacks sensitivity and is very laborious. Quantitative PCR (qPCR) has no such limitations but inaccurate quantification due to codetection of viral replicative intermediates (RI) can occur. The use of different samples, preservation conditions, DNA extraction, nuclease digestion methods and qPCR strategies has hindered standardisation. Within the ICE-HBV consortium, available and novel protocols for cccDNA isolation and qPCR quantification in liver tissues and cell cultures were compared in six laboratories to develop evidence-based guidance for best practices. DESIGN: Reference material (HBV-infected humanised mouse livers and HepG2-NTCP cells) was exchanged for cross-validation. Each group compared different DNA extraction methods (Hirt extraction, total DNA extraction with or without proteinase K treatment (+PK/-PK)) and nuclease digestion protocols (plasmid-safe ATP-dependent DNase (PSD), T5 exonuclease, exonucleases I/III). Samples were analysed by qPCR and SB. RESULTS: Hirt and -PK extraction reduced coexisting RI forms. However, both cccDNA and the protein-free relaxed circular HBV DNA (pf-rcDNA) form were detected by qPCR. T5 and Exo I/III nucleases efficiently removed all RI forms. In contrast, PSD did not digest pf-rcDNA, but was less prone to induce cccDNA overdigestion. In stabilised tissues (eg, Allprotect), nucleases had detrimental effects on cccDNA. CONCLUSIONS: We present here a comprehensive evidence-based guidance for optimising, controlling and validating cccDNA measurements using available qPCR assays.
Assuntos
DNA Circular , Vírus da Hepatite B , Animais , Camundongos , Humanos , Vírus da Hepatite B/genética , DNA Circular/genética , Fígado , Reação em Cadeia da Polimerase/métodos , Células Hep G2 , DNA Viral/genéticaRESUMO
BACKGROUND & AIMS: We recently developed a heterologous therapeutic vaccination scheme (TherVacB) comprising a particulate protein prime followed by a modified vaccinia-virus Ankara (MVA)-vector boost for the treatment of HBV. However, the key determinants required to overcome HBV-specific immune tolerance remain unclear. Herein, we aimed to study new combination adjuvants and unravel factors that are essential for the antiviral efficacy of TherVacB. METHODS: Recombinant hepatitis B surface and core antigen (HBsAg and HBcAg) particles were formulated with different liposome- or oil-in-water emulsion-based combination adjuvants containing saponin QS21 and monophosphoryl lipid A; these formulations were compared to STING-agonist c-di-AMP and conventional aluminium hydroxide formulations. Immunogenicity and the antiviral effects of protein antigen formulations and the MVA-vector boost within TherVacB were evaluated in adeno-associated virus-HBV-infected and HBV-transgenic mice. RESULTS: Combination adjuvant formulations preserved HBsAg and HBcAg integrity for ≥12 weeks, promoted human and mouse dendritic cell activation and, within TherVacB, elicited robust HBV-specific antibody and T-cell responses in wild-type and HBV-carrier mice. Combination adjuvants that prime a balanced HBV-specific type 1 and 2 T helper response induced high-titer anti-HBs antibodies, cytotoxic T-cell responses and long-term control of HBV. In the absence of an MVA-vector boost or following selective CD8 T-cell depletion, HBsAg still declined (mediated mainly by anti-HBs antibodies) but HBV replication was not controlled. Selective CD4 T-cell depletion during the priming phase of TherVacB resulted in a complete loss of vaccine-induced immune responses and its therapeutic antiviral effect in mice. CONCLUSIONS: Our results identify CD4 T-cell activation during the priming phase of TherVacB as a key determinant of HBV-specific antibody and CD8 T-cell responses. IMPACT AND IMPLICATIONS: Therapeutic vaccination is a potentially curative treatment option for chronic hepatitis B. However, it remains unclear which factors are essential for breaking immune tolerance in HBV carriers and determining successful outcomes. Our study provides the first direct evidence that efficient priming of HBV-specific CD4 T cells determines the success of therapeutic hepatitis B vaccination in two preclinical HBV-carrier mouse models. Applying an optimal formulation of HBV antigens that activates CD4 and CD8 T cells during prime immunization provided the foundation for an antiviral effect of therapeutic vaccination, while depletion of CD4 T cells led to a complete loss of vaccine-induced antiviral efficacy. Boosting CD8 T cells was important to finally control HBV in these mouse models. Our findings provide important insights into the rational design of therapeutic vaccines for the cure of chronic hepatitis B.
Assuntos
Vacinas contra Hepatite B , Hepatite B Crônica , Camundongos , Humanos , Animais , Vírus da Hepatite B , Antígenos de Superfície da Hepatite B , Antígenos do Núcleo do Vírus da Hepatite B , Linfócitos T CD4-Positivos , Imunização , Vacinação/métodos , Anticorpos Anti-Hepatite B , Linfócitos T CD8-Positivos , Camundongos Transgênicos , Adjuvantes Imunológicos , AntiviraisRESUMO
While Mpox virus (MPXV) diagnostics were performed in specialized laboratories only, the global emergence of Mpox cases in 2022 revealed the need for a more readily available diagnostic. Automated random-access platforms with fast nucleic acid extraction and PCR have become established in many laboratories, providing faster and more accessible testing. In this study, we adapted a previously published generic MPXV-PCR as a lab-developed test (LDT) on a NeuMoDx Molecular System and isolated MPXV clones from patient materials. To reduce the handling of infectious material, we evaluated a viral lysis buffer (VLB) for sample pretreatment. We further compared the MPXV-LDT-PCR to conventional real-time PCR, determined its sensitivity and specificity using positive swabs, and assessed its performance using external quality assessment samples. Pretreatment of samples with 50% VLB reduced MPXV infectivity by approximately 200-fold while maintaining PCR sensitivity. The assay demonstrated a sensitivity and specificity of 100% with no cross-reactivity in the samples tested and performed with a limit of detection of 262 GE/mL. In summary, the assay had a turnaround time of fewer than 2 h and can easily be transferred to other automated PCR platforms, providing a basis for developing rapid assays for upcoming pandemics.
Assuntos
Monkeypox virus , Mpox , Técnicas de Amplificação de Ácido Nucleico , Humanos , Monkeypox virus/genética , Monkeypox virus/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e Especificidade , Mpox/diagnósticoRESUMO
Diagnostic tests for direct pathogen detection have been instrumental to contain the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic. Automated, quantitative, laboratory-based nucleocapsid antigen (Ag) tests for SARS-CoV-2 have been launched alongside nucleic acid-based test systems and point-of-care (POC) lateral-flow Ag tests. Here, we evaluated four commercial Ag tests on automated platforms for the detection of different sublineages of the SARS-CoV-2 Omicron variant of concern (VoC) (B.1.1.529) in comparison with "non-Omicron" VoCs. A total of 203 Omicron PCR-positive respiratory swabs (53 BA.1, 48 BA.2, 23 BQ.1, 39 XBB.1.5 and 40 other subvariants) from the period February to March 2022 and from March 2023 were examined. In addition, tissue culture-expanded clinical isolates of Delta (B.1.617.2), Omicron-BA.1, -BF.7, -BN.1 and -BQ.1 were studied. These results were compared to previously reported data from 107 clinical "non-Omicron" samples from the end of the second pandemic wave (February to March 2021) as well as cell culture-derived samples of wildtype (wt) EU-1 (B.1.177), Alpha VoC (B.1.1.7) and Beta VoC (B.1.351)). All four commercial Ag tests were able to detect at least 90.9% of Omicron-containing samples with high viral loads (Ct < 25). The rates of true-positive test results for BA.1/BA.2-positive samples with intermediate viral loads (Ct 25-30) ranged between 6.7% and 100.0%, while they dropped to 0 to 15.4% for samples with low Ct values (> 30). This heterogeneity was reflected also by the tests' 50%-limit of detection (LoD50) values ranging from 44,444 to 1,866,900 Geq/ml. Respiratory samples containing Omicron-BQ.1/XBB.1.5 or other Omicron subvariants that emerged in 2023 were detected with enormous heterogeneity (0 to 100%) for the intermediate and low viral load ranges with LoD50 values between 23,019 and 1,152,048 Geq/ml. In contrast, detection of "non-Omicron" samples was more sensitive, scoring positive in 35 to 100% for the intermediate and 1.3 to 32.9% of cases for the low viral loads, respectively, corresponding to LoD50 values ranging from 6181 to 749,792 Geq/ml. All four assays detected cell culture-expanded VoCs Alpha, Beta, Delta and Omicron subvariants carrying up to six amino acid mutations in the nucleocapsid protein with sensitivities comparable to the non-VoC EU-1. Overall, automated quantitative SARS-CoV-2 Ag assays are not more sensitive than standard rapid antigen tests used in POC settings and show a high heterogeneity in performance for VoC recognition. The best of these automated Ag tests may have the potential to complement nucleic acid-based assays for SARS-CoV-2 diagnostics in settings not primarily focused on the protection of vulnerable groups. In light of the constant emergence of new Omicron subvariants and recombinants, most recently the XBB lineage, these tests' performance must be regularly re-evaluated, especially when new VoCs carry mutations in the nucleocapsid protein or immunological and clinical parameters change.
Assuntos
COVID-19 , Ácidos Nucleicos , Humanos , SARS-CoV-2/genética , COVID-19/diagnóstico , Proteínas do NucleocapsídeoRESUMO
Hepatitis B virus (HBV) persists by depositing a covalently closed circular DNA (cccDNA) in the nucleus of infected cells that cannot be targeted by available antivirals. Interferons can diminish HBV cccDNA via APOBEC3-mediated deamination. Here, we show that overexpression of APOBEC3A alone is not sufficient to reduce HBV cccDNA that requires additional treatment of cells with interferon indicating involvement of an interferon-stimulated gene (ISG) in cccDNA degradation. Transcriptome analyses identify ISG20 as the only type I and II interferon-induced, nuclear protein with annotated nuclease activity. ISG20 localizes to nucleoli of interferon-stimulated hepatocytes and is enriched on deoxyuridine-containing single-stranded DNA that mimics transcriptionally active, APOBEC3A-deaminated HBV DNA. ISG20 expression is detected in human livers in acute, self-limiting but not in chronic hepatitis B. ISG20 depletion mitigates the interferon-induced loss of cccDNA, and co-expression with APOBEC3A is sufficient to diminish cccDNA. In conclusion, non-cytolytic HBV cccDNA decline requires the concerted action of a deaminase and a nuclease. Our findings highlight that ISGs may cooperate in their antiviral activity that may be explored for therapeutic targeting.
Assuntos
DNA Circular , Vírus da Hepatite B , Antivirais/farmacologia , Citidina Desaminase , DNA Circular/genética , DNA Viral/genética , DNA Viral/farmacologia , Exorribonucleases , Vírus da Hepatite B/genética , Humanos , Interferons , Proteínas , Replicação ViralRESUMO
Due to the limited host range of HBV, research progress has been hindered by the absence of a suitable animal model. The natural history of woodchuck hepatitis virus (WHV) infection in woodchuck closely mirrors that of HBV infection in human, making this species a promising candidate for establishing both in vivo and in vitro HBV infection models. Therefore, this animal may be a valuable species to evaluate HBV vaccines and anti-HBV drugs. A significant milestone in HBV and hepatitis D virus (HDV) infection is the discovery of sodium taurocholate cotransporting polypeptide (NTCP) as the functional receptor. In an effort to enhance susceptibility to HBV infection, we introduced hNTCP into the woodchuck hepatocytes by multiple approaches including transduction of vLentivirus-hNTCP in woodchuck hepatocytes, transfection of p-lentivirus-hNTCP-eGFP plasmids into these cells, as well as transduction of vAdenovirus-hNTCP-eGFP. Encouragingly, our findings demonstrated the successful introduction of hNTCP into woodchuck hepatocytes. However, it was observed that these hNTCP-expressing hepatocytes were only susceptible to HDV infection but not HBV. This suggests the presence of additional crucial factors mediating early-stage HBV infection that are subject to stringent species-specific restrictions.
Assuntos
Hepatite B , Hepatite D , Animais , Humanos , Vírus da Hepatite B/genética , Marmota , Hepatócitos , Transportadores de Ânions Orgânicos Dependentes de Sódio/genética , Vírus Delta da Hepatite/genética , Internalização do VírusRESUMO
CD8+ T cells are key mediators of antiviral and antitumor immunity. The isolation and study of Ag-specific CD8+ T cells, as well as mapping of their MHC restriction, has practical importance to the study of disease and the development of therapeutics. Unfortunately, most experimental approaches are cumbersome, owing to the highly variable and donor-specific nature of MHC-bound peptide/TCR interactions. Here we present a novel system for rapid identification and characterization of Ag-specific CD8+ T cells, particularly well suited for samples with limited primary cells. Cells are stimulated ex vivo with Ag of interest, followed by live cell sorting based on surface-trapped TNF-α. We take advantage of major advances in single-cell sequencing to generate full-length sequence data from the paired TCR α- and ß-chains from these Ag-specific cells. The paired TCR chains are cloned into retroviral vectors and used to transduce donor CD8+ T cells. These TCR transductants provide a virtually unlimited experimental reagent, which can be used for further characterization, such as minimal epitope mapping or identification of MHC restriction, without depleting primary cells. We validated this system using CMV-specific CD8+ T cells from rhesus macaques, characterizing an immunodominant Mamu-A1*002:01-restricted epitope. We further demonstrated the utility of this system by mapping a novel HLA-A*68:02-restricted HIV Gag epitope from an HIV-infected donor. Collectively, these data validate a new strategy to rapidly identify novel Ags and characterize Ag-specific CD8+ T cells, with applications ranging from the study of infectious disease to immunotherapeutics and precision medicine.
Assuntos
Linfócitos T CD8-Positivos , Infecções por HIV , Animais , Epitopos , Epitopos de Linfócito T , Macaca mulatta , Receptores de Antígenos de Linfócitos T , Fator de Necrose Tumoral alfaRESUMO
The SARS-CoV-2 pandemic has shown the importance of rapid and comprehensive diagnostic tools. While there are numerous rapid antigen tests available, rapid serological assays for the detection of neutralizing antibodies are and will be needed to determine not only the amount of antibodies formed after infection or vaccination but also their neutralizing potential, preventing the cell entry of SARS-CoV-2. Current active-virus neutralization assays require biosafety level 3 facilities, while virus-free surrogate assays are more versatile in applications, but still take typically several hours until results are available. To overcome these disadvantages, we developed a competitive chemiluminescence immunoassay that enables the detection of neutralizing SARS-CoV-2 antibodies within 7 min. The neutralizing antibodies bind to the viral receptor binding domain (RBD) and inhibit the binding to the human angiotensin-converting enzyme 2 (ACE2) receptor. This competitive binding inhibition test was characterized with a set of 80 samples, which could all be classified correctly. The assay results favorably compare to those obtained with a more time-intensive ELISA-based neutralization test and a commercial surrogate neutralization assay. Our test could further be used to detect individuals with a high total IgG antibody titer, but only a low neutralizing titer, as well as for monitoring neutralizing antibodies after vaccinations. This effective performance in SARS-CoV-2 seromonitoring delineates the potential for the test to be adapted to other diseases in the future.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/diagnóstico , Ensaio de Imunoadsorção Enzimática , Imunoensaio , Luminescência , Automação LaboratorialRESUMO
We aimed to analyse whether patients with ischaemic stroke (IS) occurring within eight days after the onset of COVID-19 (IS-COV) are associated with a specific aetiology of IS. We used SUPERGNOVA to identify genome regions that correlate between the IS-COV cohort (73 IS-COV cases vs. 701 population controls) and different aetiological subtypes. Polygenic risk scores (PRSs) for each subtype were generated and tested in the IS-COV cohort using PRSice-2 and PLINK to find genetic associations. Both analyses used the IS-COV cohort and GWAS from MEGASTROKE (67,162 stroke patients vs. 454,450 population controls), GIGASTROKE (110,182 vs. 1,503,898), and the NINDS Stroke Genetics Network (16,851 vs. 32,473). Three genomic regions were associated (p-value < 0.05) with large artery atherosclerosis (LAA) and cardioembolic stroke (CES). We found four loci targeting the genes PITX2 (rs10033464, IS-COV beta = 0.04, p-value = 2.3 × 10-2, se = 0.02), previously associated with CES, HS6ST1 (rs4662630, IS-COV beta = -0.04, p-value = 1.3 × 10-3, se = 0.01), TMEM132E (rs12941838 IS-COV beta = 0.05, p-value = 3.6 × 10-4, se = 0.01), and RFFL (rs797989 IS-COV beta = 0.03, p-value = 1.0 × 10-2, se = 0.01). A statistically significant PRS was observed for LAA. Our results suggest that IS-COV cases are genetically similar to LAA and CES subtypes. Larger cohorts are needed to assess if the genetic factors in IS-COV cases are shared with the general population or specific to viral infection.
Assuntos
Aterosclerose , Isquemia Encefálica , COVID-19 , AVC Embólico , AVC Isquêmico , Acidente Vascular Cerebral , Humanos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/genética , Isquemia Encefálica/complicações , Isquemia Encefálica/genética , COVID-19/complicações , COVID-19/genética , AVC Isquêmico/genética , ArtériasRESUMO
Hospital staff are at high risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the coronavirus disease (COVID-19) pandemic. This cross-sectional study aimed to determine the prevalence of SARS-CoV-2 infection in hospital staff at the University Hospital rechts der Isar in Munich, Germany, and identify modulating factors. Overall seroprevalence of SARS-CoV-2-IgG in 4,554 participants was 2.4%. Staff engaged in direct patient care, including those working in COVID-19 units, had a similar probability of being seropositive as non-patient-facing staff. Increased probability of infection was observed in staff reporting interactions with SARS-CoV-2âinfected coworkers or private contacts or exposure to COVID-19 patients without appropriate personal protective equipment. Analysis of spatiotemporal trajectories identified that distinct hotspots for SARS-CoV-2âpositive staff and patients only partially overlap. Patient-facing work in a healthcare facility during the SARS-CoV-2 pandemic might be safe as long as adequate personal protective equipment is used and infection prevention practices are followed inside and outside the hospital.
Assuntos
COVID-19 , SARS-CoV-2 , Estudos Transversais , Alemanha/epidemiologia , Pessoal de Saúde , Hospitais Universitários , Humanos , Imunoglobulina G , Controle de Infecções , Recursos Humanos em Hospital , Prevalência , Estudos SoroepidemiológicosRESUMO
Lateral-flow immunoassays and laboratory diagnostic tests like enzyme-linked immunosorbent assays (ELISAs) are powerful diagnostic tools to help fight the COVID-19 pandemic using them as antigen or antibody tests. However, the need emerges for alternative bioanalytical systems that combine their favorable featuresâsimple, rapid, and cost-efficient point-of-care (POC) analysis of lateral-flow immunoassays and higher reliability of laboratory testsâwhile eliminating their disadvantages (limited sensitivity and specificity of lateral-flow assays and prolonged time and work expenditure of laboratory analysis). An additional need met by only a few tests is multiplexing, allowing for the analysis of several immunorecognition patterns at the same time. We herein present a strategy to combine all desirable attributes of the different test types by means of a flow-based chemiluminescence microarray immunoassay. Laminated polycarbonate microarray chips were developed for easy production and subsequent application in the fully automated microarray analysis platform MCR-R, where a novel flow cell design minimizes the sample volume to 40 µL. This system was capable of detecting IgG antibodies to SARS-CoV-2 with 100% sensitivity and specificity using recombinant antigens for the SARS-CoV-2 spike S1 protein, nucleocapsid protein, and receptor binding domain. The analysis was accomplished within under 4 min from serum, plasma, and whole blood, making it also useful in POC settings. Additionally, we showed the possibility of serosurveillance after infection or vaccination to monitor formerly unnoticed breakthrough infections in the population as well as to detect the need for booster vaccination after the natural decline of the antibody titer below detectable levels. This will help in answering pressing questions on the importance of the antibody response to SARS-CoV-2 that so far remain open. Additionally, even the sequential detection of IgM and IgG antibodies was possible, allowing for statements on the time response of an infection. While our serodiagnostic application focuses on SARS-CoV-2, the same approach is easily adjusted to other diseases, making it a powerful tool for future serological testing.