RESUMO
Bats are special in their ability to live long and host many emerging viruses. Our previous studies showed that bats have altered inflammasomes, which are central players in aging and infection. However, the role of inflammasome signaling in combating inflammatory diseases remains poorly understood. Here, we report bat ASC2 as a potent negative regulator of inflammasomes. Bat ASC2 is highly expressed at both the mRNA and protein levels and is highly potent in inhibiting human and mouse inflammasomes. Transgenic expression of bat ASC2 in mice reduced the severity of peritonitis induced by gout crystals and ASC particles. Bat ASC2 also dampened inflammation induced by multiple viruses and reduced mortality of influenza A virus infection. Importantly, it also suppressed SARS-CoV-2-immune-complex-induced inflammasome activation. Four key residues were identified for the gain of function of bat ASC2. Our results demonstrate that bat ASC2 is an important negative regulator of inflammasomes with therapeutic potential in inflammatory diseases.
Assuntos
Proteínas Reguladoras de Apoptose , Quirópteros , Inflamassomos , Ribonucleoproteínas , Viroses , Animais , Humanos , Camundongos , Proteínas Reguladoras de Apoptose/metabolismo , Quirópteros/imunologia , COVID-19 , Inflamassomos/imunologia , Ribonucleoproteínas/metabolismo , SARS-CoV-2 , Viroses/imunologia , Fenômenos Fisiológicos ViraisRESUMO
Bats are reservoir hosts of many zoonotic viruses with pandemic potential. We utilized single-cell transcriptome sequencing (scRNA-seq) to analyze the immune response in bat lungs upon in vivo infection with a double-stranded RNA virus, Pteropine orthoreovirus PRV3M. Bat neutrophils were distinguished by high basal IDO1 expression. NK cells and T cells were the most abundant immune cells in lung tissue. Three distinct CD8+ effector T cell populations could be delineated by differential expression of KLRB1, GFRA2, and DPP4. Select NK and T clusters increased expression of genes involved in T cell activation and effector function early after viral infection. Alveolar macrophages and classical monocytes drove antiviral interferon signaling. Infection expanded a CSF1R+ population expressing collagen-like genes, which became the predominant myeloid cell type post-infection. This work uncovers features relevant to viral disease tolerance in bats, lays a foundation for future experimental work, and serves as a resource for comparative immunology studies.
Assuntos
Quirópteros , Viroses , Animais , Quirópteros/genética , Néctar de Plantas , Transcriptoma , Análise de Célula Única , Perfilação da Expressão GênicaRESUMO
Current coronavirus disease 2019 vaccines face limitations including waning immunity, immune escape by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, limited cellular response, and poor mucosal immunity. We engineered a Clec9A-receptor binding domain (RBD) antibody construct that delivers the SARS-CoV-2 RBD to conventional type 1 dendritic cells. Compared with non-targeting approaches, single dose immunization in mice with Clec9A-RBD induced far higher RBD-specific antibody titers that were sustained for up to 21 months after vaccination. Uniquely, increasing neutralizing and antibody-dependent cytotoxicity activities across the sarbecovirus family was observed, suggesting antibody affinity maturation over time. Consistently and remarkably, RBD-specific follicular T helper cells and germinal center B cells persisted up to 12 months after immunization. Furthermore, Clec9A-RBD immunization induced a durable mono- and poly-functional T-helper 1-biased cellular response that was strongly cross-reactive against SARS-CoV-2 variants of concern, including Omicron subvariants, and with a robust CD8+ T cell signature. Uniquely, Clec9A-RBD single-shot systemic immunization effectively primed RBD-specific cellular and humoral immunity in lung and resulted in significant protection against homologous SARS-CoV-2 challenge as evidenced by limited body weight loss and approximately 2 log10 decrease in lung viral loads compared with non-immunized controls. Therefore, Clec9A-RBD immunization has the potential to trigger robust and sustained, systemic and mucosal protective immunity against rapidly evolving SARS-CoV2 variants.
Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Vacinas contra COVID-19 , COVID-19 , Células Dendríticas , Imunidade nas Mucosas , Lectinas Tipo C , SARS-CoV-2 , Animais , Camundongos , Células Dendríticas/imunologia , SARS-CoV-2/imunologia , COVID-19/prevenção & controle , COVID-19/imunologia , COVID-19/virologia , Vacinas contra COVID-19/imunologia , Lectinas Tipo C/imunologia , Lectinas Tipo C/metabolismo , Anticorpos Antivirais/imunologia , Anticorpos Neutralizantes/imunologia , Humanos , Feminino , Glicoproteína da Espícula de Coronavírus/imunologia , Receptores Mitogênicos/imunologia , Citotoxicidade Celular Dependente de Anticorpos/imunologia , Receptores ImunológicosRESUMO
Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern pose a challenge to the effectiveness of current vaccines. A vaccine that could prevent infection caused by known and future variants of concern as well as infection with pre-emergent sarbecoviruses (i.e., those with potential to cause disease in humans in the future) would be ideal. Here we provide data showing that potent cross-clade pan-sarbecovirus neutralizing antibodies are induced in survivors of severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) infection who have been immunized with the BNT162b2 messenger RNA (mRNA) vaccine. The antibodies are high-level and broad-spectrum, capable of neutralizing not only known variants of concern but also sarbecoviruses that have been identified in bats and pangolins and that have the potential to cause human infection. These findings show the feasibility of a pan-sarbecovirus vaccine strategy. (Funded by the Singapore National Research Foundation and National Medical Research Council.).
Assuntos
Anticorpos Antivirais/sangue , Anticorpos Amplamente Neutralizantes/sangue , Vacinas contra COVID-19/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Síndrome Respiratória Aguda Grave/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia , Linfócitos B , Vacina BNT162 , Humanos , Imunogenicidade da Vacina , Filogenia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/genética , SARS-CoV-2/genética , SobreviventesRESUMO
BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may be associated with worse clinical outcomes in people with human immunodeficiency virus (HIV) (PWH). We report anti-SARS-CoV-2 antibody responses in patients hospitalized with coronavirus disease 2019 in Durban, South Africa, during the second SARS-CoV-2 infection wave dominated by the Beta (B.1.351) variant. METHODS: Thirty-four participants with confirmed SARS-CoV-2 infection were followed up with weekly blood sampling to examine antibody levels and neutralization potency against SARS-CoV-2 variants. Participants included 18 PWH, of whom 11 were HIV viremic. RESULTS: SARS-CoV-2-specific antibody concentrations were generally lower in viremic PWH than in virologically suppressed PWH and HIV-negative participants, and neutralization of the Beta variant was 4.9-fold lower in viremic PWH. Most HIV-negative participants and antiretroviral therapy-suppressed PWH also neutralized the Delta (B.1.617.2) variant, whereas the majority of viremic PWH did not. CD4 cell counts <500/µL were associated with lower frequencies of immunoglobulin G and A seroconversion. In addition, there was a high correlation between a surrogate virus neutralization test and live virus neutralization against ancestral SARS-CoV-2 virus in both PWH and HIV-negative individuals, but correlation decreased for the Beta variant neutralization in PWH. CONCLUSIONS: HIV viremia was associated with reduced Beta variant neutralization. This highlights the importance of HIV suppression in maintaining an effective SARS-CoV-2 neutralization response.
Assuntos
COVID-19 , Infecções por HIV , Humanos , SARS-CoV-2 , HIV , Viremia , África do Sul/epidemiologia , Anticorpos Antivirais , Infecções por HIV/tratamento farmacológico , Glicoproteína da Espícula de Coronavírus , Anticorpos Neutralizantes , Testes de NeutralizaçãoRESUMO
Mucosal antibodies play a key role in protection against breakthrough COVID-19 infections and emerging viral variants. Intramuscular adenovirus-based vaccination (Vaxzevria) only weakly induces nasal IgG and IgA responses, unless vaccinees have been previously infected. However, little is known about how Vaxzevria vaccination impacts the ability of mucosal antibodies to induce Fc responses, particularly against SARS-CoV-2 variants of concern (VoCs). Here, we profiled paired mucosal (saliva, tears) and plasma antibodies from COVID-19 vaccinated only vaccinees (uninfected, vaccinated) and COVID-19 recovered vaccinees (COVID-19 recovered, vaccinated) who both received Vaxzevria vaccines. SARS-CoV-2 ancestral-specific IgG antibodies capable of engaging FcγR3a were significantly higher in the mucosal samples of COVID-19 recovered Vaxzevria vaccinees in comparison with vaccinated only vaccinees. However, when IgG and FcγR3a engaging antibodies were tested against a panel of SARS-CoV-2 VoCs, the responses were ancestral-centric with weaker recognition of Omicron strains observed. In contrast, salivary IgA, but not plasma IgA, from Vaxzevria vaccinees displayed broad cross-reactivity across all SARS-CoV-2 VoCs tested. Our data highlight that while intramuscular Vaxzevria vaccination can enhance mucosal antibodies responses in COVID-19 recovered vaccinees, restrictions by ancestral-centric bias may have implications for COVID-19 protection. However, highly cross-reactive mucosal IgA could be key in addressing these gaps in mucosal immunity and may be an important focus of future SARS-CoV-2 vaccine development.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Humanos , Formação de Anticorpos , ChAdOx1 nCoV-19 , Vacinação , COVID-19/prevenção & controle , Anticorpos Antivirais , Imunoglobulina A , Imunoglobulina G , Anticorpos NeutralizantesRESUMO
BACKGROUND: Waning antibody levels post-vaccination and the emergence of variants of concern (VOCs) capable of evading protective immunity have raised the need for booster vaccinations. However, which combination of coronavirus disease 2019 (COVID-19) vaccines offers the strongest immune response against the Omicron variant is unknown. METHODS: This randomized, participant-blinded, controlled trial assessed the reactogenicity and immunogenicity of different COVID-19 vaccine booster combinations. A total of 100 BNT162b2-vaccinated individuals were enrolled and randomized 1:1 to either homologous (BNT162b2 + BNT162b2 + BNT162b2; "BBB") or heterologous messenger RNA (mRNA) (BNT162b2 + BNT162b2 + mRNA-1273; "BBM") booster vaccine. The primary end point was the level of neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wild-type and VOCs at day 28. RESULTS: A total of 51 participants were allocated to BBB and 49 to BBM; 50 and 48, respectively, were analyzed for safety and immunogenicity outcomes. At day 28 post-boost, mean SARS-CoV-2 spike antibody titers were lower with BBB (22 382â IU/mL; 95% confidence interval [CI], 18 210 to 27 517) vs BBM (29 751â IU/mL; 95% CI, 25 281 to 35 011; P = .034) as was the median level of neutralizing antibodies: BBB 99.0% (interquartile range [IQR], 97.9% to 99.3%) vs BBM 99.3% (IQR, 98.8% to 99.5%; P = .021). On subgroup analysis, significant higher mean spike antibody titer, median surrogate neutralizing antibody level against all VOCs, and live Omicron neutralization titer were observed only in older adults receiving BBM. Both vaccines were well tolerated. CONCLUSIONS: Heterologous mRNA-1273 booster vaccination compared with homologous BNT123b2 induced a stronger neutralizing response against the Omicron variant in older individuals. CLINICAL TRIALS REGISTRATION: NCT05142319.
Assuntos
Vacina BNT162 , COVID-19 , Humanos , Idoso , SARS-CoV-2 , Formação de Anticorpos , Vacina de mRNA-1273 contra 2019-nCoV , Vacinação , Anticorpos Neutralizantes , Anticorpos AntiviraisRESUMO
The novel coronavirus SARS-CoV-2 is the causative agent of Coronavirus Disease 2019 (COVID-19), a global healthcare and economic catastrophe. Understanding of the host immune response to SARS-CoV-2 is still in its infancy. A 382-nt deletion strain lacking ORF8 (Δ382 herein) was isolated in Singapore in March 2020. Infection with Δ382 was associated with less severe disease in patients, compared to infection with wild-type SARS-CoV-2. Here, we established Nasal Epithelial cells (NECs) differentiated from healthy nasal-tissue derived stem cells as a suitable model for the ex-vivo study of SARS-CoV-2 mediated pathogenesis. Infection of NECs with either SARS-CoV-2 or Δ382 resulted in virus particles released exclusively from the apical side, with similar replication kinetics. Screening of a panel of 49 cytokines for basolateral secretion from infected NECs identified CXCL10 as the only cytokine significantly induced upon infection, at comparable levels in both wild-type and Δ382 infected cells. Transcriptome analysis revealed the temporal up-regulation of distinct gene subsets during infection, with anti-viral signaling pathways only detected at late time-points (72 hours post-infection, hpi). This immune response to SARS-CoV-2 was significantly attenuated when compared to infection with an influenza strain, H3N2, which elicited an inflammatory response within 8 hpi, and a greater magnitude of anti-viral gene up-regulation at late time-points. Remarkably, Δ382 induced a host transcriptional response nearly identical to that of wild-type SARS-CoV-2 at every post-infection time-point examined. In accordance with previous results, Δ382 infected cells showed an absence of transcripts mapping to ORF8, and conserved expression of other SARS-CoV-2 genes. Our findings shed light on the airway epithelial response to SARS-CoV-2 infection, and demonstrate a non-essential role for ORF8 in modulating host gene expression and cytokine production from infected cells.
Assuntos
COVID-19/virologia , Mucosa Nasal/virologia , SARS-CoV-2/genética , SARS-CoV-2/patogenicidade , Proteínas Virais/genética , Quimiocina CXCL10/imunologia , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Células Epiteliais/virologia , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Cinética , Mucosa Nasal/imunologia , Mucosa Nasal/metabolismo , Transcriptoma , Proteínas Virais/imunologia , Replicação Viral/fisiologiaRESUMO
BACKGROUND: Key knowledge gaps remain in the understanding of viral dynamics and immune response of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. METHODS: We evaluated these characteristics and established their association with clinical severity in a prospective observational cohort study of 100 patients with PCR-confirmed SARS-CoV-2 infection (mean age, 46 years; 56% male; 38% with comorbidities). Respiratory samples (n = 74) were collected for viral culture, serum samples for measurement of IgM/IgG levels (n = 30), and plasma samples for levels of inflammatory cytokines and chemokines (n = 81). Disease severity was correlated with results from viral culture, serologic testing, and immune markers. RESULTS: Fifty-seven (57%) patients developed viral pneumonia, of whom 20 (20%) required supplemental oxygen, including 12 (12%) with invasive mechanical ventilation. Viral culture from respiratory samples was positive for 19 of 74 patients (26%). No virus was isolated when the PCR cycle threshold (Ct) value was >30 or >14 days after symptom onset. Seroconversion occurred at a median (IQR) of 12.5 (9-18) days for IgM and 15.0 (12-20) days for IgG; 54/62 patients (87.1%) sampled at day 14 or later seroconverted. Severe infections were associated with earlier seroconversion and higher peak IgM and IgG levels. Levels of IP-10, HGF, IL-6, MCP-1, MIP-1α, IL-12p70, IL-18, VEGF-A, PDGF-BB, and IL-1RA significantly correlated with disease severity. CONCLUSIONS: We found virus viability was associated with lower PCR Ct value in early illness. A stronger antibody response was associated with disease severity. The overactive proinflammatory immune signatures offer targets for host-directed immunotherapy, which should be evaluated in randomized controlled trials.
Assuntos
COVID-19 , Pneumonia Viral , Anticorpos Antivirais , Feminino , Humanos , Imunoglobulina M , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , SARS-CoV-2 , SoroconversãoRESUMO
Enterovirus A71 (EV-A71) causes hand, foot and mouth disease epidemics with neurological complications and fatalities. However, the neuropathogenesis of EV-A71 remains poorly understood. In mice, adaptation and virulence determinants have been mapped to mutations at VP2-149, VP1-145 and VP1-244. We investigate how these amino acids alter heparin-binding phenotype and shapes EV-A71 virulence in one-day old mice. We constructed six viruses with varying residues at VP1-98, VP1-145 (which are both heparin-binding determinants) and VP2-149 (based on the wild type 149K/98E/145Q, termed KEQ) to generate KKQ, KKE, KEE, IEE and IEQ variants. We demonstrated that the weak heparin-binder IEE was highly lethal in mice. The initially strong heparin-binding IEQ variant acquired an additional mutation VP1-K244E, which confers weak heparin-binding phenotype resulting in elevated viremia and increased virus antigens in mice brain, with subsequent high virulence. IEE and IEQ-244E variants inoculated into mice disseminated efficiently and displayed high viremia. Increasing polymerase fidelity and impairing recombination of IEQ attenuated the virulence, suggesting the importance of population diversity in EV-A71 pathogenesis in vivo. Combining in silico docking and deep sequencing approaches, we inferred that virus population diversity is shaped by electrostatic interactions at the five-fold axis of the virus surface. Electrostatic surface charges facilitate virus adaptation by generating poor heparin-binding variants for better in vivo dissemination in mice, likely due to reduced adsorption to heparin-rich peripheral tissues, which ultimately results in increased neurovirulence. The dynamic switching between heparin-binding and weak heparin-binding phenotype in vivo explained the neurovirulence of EV-A71.
Assuntos
Encéfalo/virologia , Proteínas do Capsídeo/metabolismo , Enterovirus Humano A/genética , Infecções por Enterovirus/virologia , Enterovirus/genética , Heparina/metabolismo , Fatores de Virulência/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas do Capsídeo/química , Proteínas do Capsídeo/genética , Enterovirus/química , Infecções por Enterovirus/epidemiologia , Infecções por Enterovirus/metabolismo , Heparina/química , Interações Hospedeiro-Patógeno , Humanos , Camundongos , Camundongos Endogâmicos ICR , Mutação , Fenótipo , Eletricidade Estática , Células Tumorais Cultivadas , Virulência , Fatores de Virulência/química , Fatores de Virulência/genética , Replicação ViralAssuntos
Febre , Infecções por Henipavirus , Henipavirus , Zoonoses Virais , Animais , China/epidemiologia , Febre/etiologia , Infecções por Henipavirus/complicações , Infecções por Henipavirus/epidemiologia , Humanos , Proteínas do Envelope Viral , Zoonoses Virais/complicações , Zoonoses Virais/epidemiologiaRESUMO
Enterovirus A71 (EV-A71) from the Picornaviridae family is an important emerging pathogen causing hand, foot, and mouth disease (HFMD) outbreaks worldwide. EV-A71 also caused fatal neurological complications in young children especially in Asia. On the basis of seroepidemiological studies from many Asian countries, EV-A71 infection is very common. Children of very young age are particularly vulnerable. Large-scale epidemics that occur every 3 to 4 years are associated with accumulation of an immunologically naive younger population. Capsid proteins especially VP1 with the presence of major B- and T-cell epitopes are the most antigenic proteins. The nonstructural proteins mainly contribute to T-cell epitopes that induce cross-reactive immune responses against other enteroviruses. Dominant epitopes and their neutralization magnitudes differ in mice, rabbits, and humans. Neutralizing antibody is sufficient for immune protection, but poorer cellular immunity may lead to severe neurological complications and deaths. Some chemokines/cytokines are consistently found in severely ill patients, for example, IL-6, IL-10, IL-17A, MCP-1, IL-8, MIG, IP-10, IFN-γ, and G-CSF. An increase in white cell counts is a risk factor for severe HFMD. Recent clinical trials on EV-A71 inactivated vaccine showed >90% efficacy and a robust neutralization response that was protective, indicating neutralizing antibody correlates for protection. No protection against other enteroviruses was observed. A comprehensive understanding of the immune responses to EV-A71 infection will benefit the development of diagnostic tools, potential therapeutics, and subunit vaccine candidates. Future development of a multivalent enterovirus vaccine will require knowledge of correlates of protection, understanding of cross-protection and memory T-cell responses among enteroviruses.
Assuntos
Enterovirus Humano A/imunologia , Infecções por Enterovirus/imunologia , Infecções por Enterovirus/virologia , Interações Hospedeiro-Patógeno/imunologia , Imunidade , Animais , Enterovirus Humano A/fisiologia , Infecções por Enterovirus/epidemiologia , Infecções por Enterovirus/prevenção & controle , Humanos , Estudos Soroepidemiológicos , Vacinas Virais/imunologiaRESUMO
To determine whether Pteropine orthoreovirus (PRV) exposure has occurred in Singapore, we tested 856 individuals from an existing serum panel collected from 2005-2013. After an initial screen with luciferase immunoprecipitation system and secondary confirmation with virus neutralization test, we identified at least seven individuals with specific antibodies against PRV in both assays. Our findings confirm that PRV spillover into human populations is relatively common in this region of the world.
Assuntos
Anticorpos Antivirais/sangue , Orthoreovirus/imunologia , Infecções por Reoviridae/epidemiologia , Testes Sorológicos/métodos , Zoonoses/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Infecções por Reoviridae/virologia , Estudos Soroepidemiológicos , Singapura/epidemiologia , Adulto Jovem , Zoonoses/virologiaRESUMO
Enterovirus A71 (EV-A71) neutralization escape mutants were generated with monoclonal antibody MAB979 (Millipore). The VP2-T141I and VP1-D14N substitutions were identified. Using reverse genetics, infectious clones with these substitutions were constructed and tested by neutralization assay with immune sera from mice and humans. The N-terminus VP1-14 is more important than EF loop VP2-141 in acute human infection, mainly because it recognised IgM present in acute infection. The N-terminus VP1 could be a useful target for diagnostics and therapeutic antibodies in acute infection.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Proteínas do Capsídeo/imunologia , Enterovirus Humano A/imunologia , Epitopos/imunologia , Adulto , Animais , Proteínas do Capsídeo/genética , Mapeamento de Epitopos , Epitopos/genética , Humanos , Epitopos Imunodominantes/imunologia , Camundongos , Mutação de Sentido IncorretoAssuntos
COVID-19/epidemiologia , COVID-19/imunologia , Programas de Rastreamento , Adolescente , Adulto , Idoso , Teste Sorológico para COVID-19 , Criança , Pré-Escolar , Feminino , Humanos , Malásia/epidemiologia , Masculino , Programas de Rastreamento/estatística & dados numéricos , Pessoa de Meia-Idade , Estudos Soroepidemiológicos , Adulto JovemRESUMO
Enterovirus 71 (EV-71) infections are usually associated with mild hand, foot, and mouth disease in young children but have been reported to cause severe neurological complications with high mortality rates. To date, four EV-71 receptors have been identified, but inhibition of these receptors by antagonists did not completely abolish EV-71 infection, implying that there is an as yet undiscovered receptor(s). Since EV-71 has a wide range of tissue tropisms, we hypothesize that EV-71 infections may be facilitated by using receptors that are widely expressed in all cell types, such as heparan sulfate. In this study, heparin, polysulfated dextran sulfate, and suramin were found to significantly prevent EV-71 infection. Heparin inhibited infection by all the EV-71 strains tested, including those with a single-passage history. Neutralization of the cell surface anionic charge by polycationic poly-d-lysine and blockage of heparan sulfate by an anti-heparan sulfate peptide also inhibited EV-71 infection. Interference with heparan sulfate biosynthesis either by sodium chlorate treatment or through transient knockdown of N-deacetylase/N-sulfotransferase-1 and exostosin-1 expression reduced EV-71 infection in RD cells. Enzymatic removal of cell surface heparan sulfate by heparinase I/II/III inhibited EV-71 infection. Furthermore, the level of EV-71 attachment to CHO cell lines that are variably deficient in cell surface glycosaminoglycans was significantly lower than that to wild-type CHO cells. Direct binding of EV-71 particles to heparin-Sepharose columns under physiological salt conditions was demonstrated. We conclude that EV-71 infection requires initial binding to heparan sulfate as an attachment receptor.
Assuntos
Enterovirus Humano A/fisiologia , Glicosaminoglicanos/metabolismo , Heparitina Sulfato/metabolismo , Receptores Virais/metabolismo , Ligação Viral , Animais , Linhagem Celular , HumanosRESUMO
Enterovirus 71 (EV-71) is the main etiological agent of hand, foot and mouth disease (HFMD). Recent EV-71 outbreaks in Asia-Pacific were not limited to mild HFMD, but were associated with severe neurological complications such as aseptic meningitis and brainstem encephalitis, which may lead to cardiopulmonary failure and death. The absence of licensed therapeutics for clinical use has intensified research into anti-EV-71 development. This review highlights the potential antiviral agents targeting EV-71 attachment, entry, uncoating, translation, polyprotein processing, virus-induced formation of membranous RNA replication complexes, and RNA-dependent RNA polymerase. The strategies for antiviral development include target-based synthetic compounds, anti-rhinovirus and poliovirus libraries screening, and natural compound libraries screening. Growing knowledge of the EV-71 life cycle will lead to successful development of antivirals. The continued effort to develop antiviral agents for treatment is crucial in the absence of a vaccine. The coupling of antivirals with an effective vaccine will accelerate eradication of the disease.
Assuntos
Antivirais/uso terapêutico , Enterovirus Humano A/efeitos dos fármacos , Enterovirus Humano A/genética , Infecções por Enterovirus/tratamento farmacológico , Antivirais/química , Enterovirus Humano A/patogenicidade , Infecções por Enterovirus/genética , Infecções por Enterovirus/patologia , Humanos , RNA Polimerase Dependente de RNA/efeitos dos fármacos , Replicação Viral/efeitos dos fármacosRESUMO
Heterologous Sinovac-CoronaVac booster(s) in 12-17-year-olds who had a moderate/severe reaction to Pfizer-BNT162b2 mRNA vaccine was found to safe with no serious adverse events reported. In those primed with 1 dose of Pfizer-BNT162b2 vaccine, subsequent boosters with 2 doses of Sinovac-CoronaVac vaccines achieved neutralizing antibody levels which were comparable to those who had received 2 doses of Pfizer-BNT162b2 vaccines followed by 1 dose of Sinovac-CoronaVac vaccination. Adolescents with 1 Pfizer-BNT162b2 followed by 2 Sinovac-CoronaVac vaccines developed T-cell responses against broad peptides including membrane, nucleoprotein 1 and 2 but levels were highest for Spike protein and lasted until day 150 post-vaccination.
Assuntos
Vacina BNT162 , Vacinação , Vacinas de Produtos Inativados , Adolescente , Humanos , Anticorpos Neutralizantes , Anticorpos Antivirais , Vacina BNT162/efeitos adversos , Vacinação/efeitos adversos , Vacinas de Produtos Inativados/efeitos adversos , CriançaRESUMO
BACKGROUND: COVID-19 vaccines used in humans are highly effective in limiting disease and death caused by the SARS-CoV-2 virus, yet improved vaccines that provide greater protection at mucosal surfaces, which could reduce break-through infections and subsequent transmission, are still needed. METHODS: Here we tested an intranasal (I.N.) vaccination with the receptor binding domain of Spike antigen of SARS-CoV-2 (S-RBD) in combination with the mucosal adjuvant mastoparan-7 compared with the sub-cutaneous (S.C.) route, adjuvanted by either M7 or the gold-standard adjuvant, alum, in mice, for immunological read-outs. The same formulation delivered I.N. or S.C. was tested in hamsters to assess efficacy. FINDINGS: I.N. vaccination improved systemic T cell responses compared to an equivalent dose of antigen delivered S.C. and T cell phenotypes induced by I.N. vaccine administration included enhanced polyfunctionality (combined IFN-γ and TNF expression) and greater numbers of T central memory (TCM) cells. These phenotypes were T cell-intrinsic and could be recalled in the lungs and/or brachial LNs upon antigen challenge after adoptive T cell transfer to naïve recipients. Furthermore, mucosal vaccination induced antibody responses that were similarly effective in neutralising the binding of the parental strain of S-RBD to its ACE2 receptor, but showed greater cross-neutralising capacity against multiple variants of concern (VOC), compared to S.C. vaccination. I.N. vaccination provided significant protection from lung pathology compared to unvaccinated animals upon challenge with homologous and heterologous SARS-CoV-2 strains in a hamster model. INTERPRETATION: These results highlight the role of nasal vaccine administration in imprinting an immune profile associated with long-term T cell retention and diversified neutralising antibody responses, which could be applied to improve vaccines for COVID-19 and other infectious diseases. FUNDING: This study was funded by Duke-NUS Medical School, the Singapore Ministry of Education, the National Medical Research Council of Singapore and a DBT-BIRAC Grant.