Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.461
Filtrar
1.
PLoS Negl Trop Dis ; 13(11): e0007800, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31725816

RESUMO

B cell activating factor (BAFF) is a member of the tumor necrosis factor (TNF) superfamily of cytokines that links innate with adaptive immunity. BAFF signals through receptors on B cells, making it an attractive molecule to potentiate vaccine-induced B cell responses. We hypothesized that a rabies virus (RABV)-based vaccine displaying both antigen and BAFF on the surface of the same virus particle would target antigen-specific B cells for activation and improve RABV-specific antibody responses. To test this hypothesis, we constructed a recombinant RABV-based vector expressing virus membrane-anchored murine BAFF (RABV-ED51-mBAFF). BAFF was incorporated into the RABV particle and determined to be biologically functional, as demonstrated by increased B cell survival of primary murine B cells treated ex-vivo with RABV-ED51-mBAFF. B cell survival was inhibited by pre-treating RABV-ED51-mBAFF with an antibody that blocks BAFF functions. RABV-ED51-mBAFF also activated primary murine B cells ex-vivo more effectively than RABV as shown by significant upregulation of CD69, CD40, and MHCII on the surface of infected B cells. In-vivo, RABV-ED51-mBAFF induced significantly faster and higher virus neutralizing antibody (VNA) titers than RABV while not adversely affecting the longevity of the vaccine-induced antibody response. Since BAFF was incorporated into the virus particle and genome replication was not required for BAFF expression in-vivo, we hypothesized that RABV-ED51-mBAFF would be effective as an inactivated vaccine. Mice immunized with 250 ng/mouse of ß-propriolactone-inactivated RABV-ED51-mBAFF showed faster and higher anti-RABV VNA titers compared to mice immunized with inactivated RABV. Together, this model stands as a potential foundation for exploring other virus membrane-anchored molecular adjuvants to make safer, more effective inactivated RABV-based vaccines.


Assuntos
Formação de Anticorpos/imunologia , Fator Ativador de Células B/imunologia , Linfócitos B/imunologia , Vacinas Antirrábicas/imunologia , Raiva/imunologia , Raiva/prevenção & controle , Vírion/imunologia , Adjuvantes Imunológicos , Animais , Anticorpos Antivirais/sangue , Citocinas/metabolismo , Feminino , Imunização , Cinética , Camundongos , Camundongos Endogâmicos C57BL , Vacinas Antirrábicas/efeitos adversos , Vírus da Raiva/genética , Vírus da Raiva/crescimento & desenvolvimento , Vírus da Raiva/imunologia , Vacinação , Vacinas Atenuadas/imunologia , Vacinas de Produtos Inativados/efeitos adversos , Vacinas de Produtos Inativados/imunologia , Vacinas Sintéticas
2.
Int J Nanomedicine ; 14: 7533-7548, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31571862

RESUMO

Background: The influenza A virus (IAV) is known for its high variability and poses a huge threat to the health of humans and animals. Pigs play a central role in the cross-species reassortment of IAV. Ectodomain of matrix protein 2 (M2e) is the most conserved protective antigen in IAV and can be used to develop nanovaccines through nanoparticles displaying to increase its immunogenicity. However, the high immunogenicity of nanoparticles can cause the risk of off-target immune response, and excess unwanted antibodies may interfere with the protective efficacy of M2e-specific antibodies. Therefore, it is necessary to select reasonable nanoparticles to make full use of antibodies against nanoparticles while increasing the level of M2e-specific antibodies. Porcine circovirus type 2 (PCV2) is the most susceptible virus in pigs and can promote IAV infection. It is meaningful to develop a vaccine that can simultaneously control swine influenza virus (SIV) and PCV2. Methods: In the present study, M2e of different copy numbers were inserted into the capsid (Cap) protein of PCV2 and expressed in Escherichia coli to form self-assembled chimeric virus-like particles (VLPs) nanovaccine. BALB/c mice and pigs were immunized with these nanovaccines to explore optimal anti-IAV and anti-PCV2 immunity. Results: Cap is capable of carrying at least 81 amino acid residues (three copies of M2e) at its C-terminal without impairing VLPs formation. Cap-3M2e VLPs induced the highest levels of M2e-specific immune responses, conferring protection against lethal challenge of IAVs from different species and induced specific immune responses consistent with PCV2 commercial vaccines in mice. In addition, Cap-3M2e VLPs induced high levels of M2e-specific antibodies and PCV2-specific neutralizing antibodies in pigs. Conclusion: Cap-3M2e VLP is an economical and promising bivalent nanovaccine, which provides dual protection against IAV and PCV2.


Assuntos
Circovirus/imunologia , Vírus da Influenza A/imunologia , Nanopartículas/uso terapêutico , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Especificidade de Anticorpos/imunologia , Aves/virologia , Proteínas do Capsídeo/química , Proliferação de Células , Citocinas/metabolismo , Cães , Feminino , Humanos , Imunidade Humoral , Influenza Aviária/imunologia , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Linfócitos/citologia , Células Madin Darby de Rim Canino , Camundongos Endogâmicos BALB C , Testes de Neutralização , Proteínas Recombinantes/isolamento & purificação , Suínos , Vírion/imunologia , Vírion/ultraestrutura
3.
DNA Cell Biol ; 38(11): 1170-1177, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31502877

RESUMO

Host response to viral infection is a highly regulated process involving engagement of various host factors, cytokines, chemokines, and stimulatory signals that pave the way for an antiviral immune response. The response is manifested in terms of viral sequestration, phagocytosis, and inhibition of genome replication, and, finally, if required, lymphocyte-mediated clearance of virally infected cells. During this process, cross-talk between viral and host factors can shape disease outcomes and immunopathology. Bone marrow stromal antigen 2 (BST-2), also know as tetherin, is induced by type I interferon produced in response to viral infections, as well as in certain cancers. BST-2 has been shown to be a host restriction factor of virus multiplication through its ability to physically tether budding virions and restrict viral spread. However, BST-2 has other roles in the host antiviral response. This review focuses on the diverse functions of BST-2 and its downstream signaling pathways in regulating host immune responses.


Assuntos
Antígenos CD/fisiologia , Imunomodulação/genética , Vírion/imunologia , Vírion/metabolismo , Imunidade Adaptativa/genética , Animais , Antígenos CD/genética , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/fisiologia , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunomodulação/imunologia , Viroses/genética , Viroses/imunologia
4.
Hum Vaccin Immunother ; 15(10): 2328-2336, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31314657

RESUMO

The unexpectedly low vaccine efficacy of Dengvaxia®, developed by Sanofi Pasteur, and a higher risk of severe diseases after vaccination among dengue-naive children or children younger than 6 years old, have cast skepticism about the safety of dengue vaccination resulting in the suspension of school-based immunization programs in the Philippines. The absence of immune correlates of protection from dengue virus (DENV) infection hampers the development of other potential DENV vaccines. While tetravalent live-attenuated tetravalent vaccines (LATVs), which mimic natural infection by inducing both cellular and humoral immune responses, are still currently favored, developing a vaccine that provides a balanced immunity to all four DENV serotypes remains a challenge. With the recently advanced understanding of virion structure and B cell immune responses from naturally infected DENV patients, two points of view in developing a next-generation dengue vaccine emerged: one is to induce potent, type-specific neutralizing antibodies (NtAbs) recognizing quaternary structure-dependent epitopes by having four components of vaccine strains replicate equivalently; the other is to induce protective and broadly NtAbs against the four serotypes of DENV with a universal vaccine. This article reviews the studies related to these issues and the current knowledge gap that needs to be filled in.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vacinas contra Dengue/imunologia , Vírus da Dengue/imunologia , Dengue/prevenção & controle , Vírion/imunologia , Animais , Ensaios Clínicos como Assunto , Vírus da Dengue/fisiologia , Humanos , Sorogrupo , Vacinação , Vacinas Atenuadas/imunologia , Vacinas de Partículas Semelhantes a Vírus , Vírion/fisiologia
5.
PLoS One ; 14(6): e0218472, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31211801

RESUMO

Hepatitis E virus genotype 3 (HEV-3) is an emerging zoonotic pathogen, responsible for sporadic cases of acute hepatitis E worldwide. Primate models have proven to be an essential tool for the study of HEV pathogenesis. Here we describe the outcomes of HEV infection in Macaca fascicularis (cynomolgus) inoculated experimentally with genotype 3. Eight adult cynomolgus macaques were inoculated intravenously with HEV-3 viral particles isolated from swine and human samples. Liver, spleen, duodenum, gallbladder and bile were sequential assessed up to the end-point of this study, 67 days post-inoculation (dpi). Our previously published findings showed that biochemical parameters return gradually to baseline levels at 55 dpi, whereas anti-HEV IgM and HEV RNA become undetectable in the serum and feces of all animals, indicating a non-viremic phase of recovery. Nevertheless, at a later stage during convalescence (67 dpi), the presence of HEV-3 RNA and antigen persist in central organs, even after peripheral viral clearance. Our results show that two cynomolgus inoculated with swine HEV-3 (animals I3 and O1) presented persistence of HEV RNA low titers in liver, gallbladder and bile. At this same stage of infection, HEV antigen (HEV Ag) could be detected in all infected animals, predominantly in non-reactive Kupffer cells (CD68+iNOS-) and sinusoidal lining cells. Simultaneously, CD4+, CD3+CD4+, and CD3+CD8+ immune cells were identified in hepatic sinusoids and small inflammatory clusters of lobular mononuclear cells, at the end-point of this study. Inability of HEV clearance in humans can result in chronic hepatitis, liver cirrhosis, with subsequent liver failure requiring transplantation. The results of our study support the persistence of HEV-3 during convalescence at 67 dpi, with active immune response in NHP. We alert to the inherent risk of viral transmission through liver transplantation, even in the absence of clinical and biochemical signs of acute infection. Thus, besides checking conventional serological markers of HEV infection, we strongly recommend HEV-3 RNA and antigen detection in liver explants as public health measure to prevent donor-recipient transmission and spread of hepatitis E.


Assuntos
Vírus da Hepatite E/genética , Hepatite E/genética , Fígado/virologia , Macaca fascicularis/virologia , Animais , Modelos Animais de Doenças , Duodeno/patologia , Duodeno/virologia , Fezes/virologia , Vesícula Biliar/patologia , Vesícula Biliar/virologia , Genótipo , Anticorpos Anti-Hepatite/genética , Anticorpos Anti-Hepatite/imunologia , Hepatite E/imunologia , Hepatite E/patologia , Hepatite E/virologia , Vírus da Hepatite E/imunologia , Vírus da Hepatite E/patogenicidade , Humanos , Fígado/patologia , Macaca fascicularis/imunologia , Tecido Parenquimatoso/patologia , Tecido Parenquimatoso/virologia , Baço/patologia , Baço/virologia , Suínos/virologia , Vírion/genética , Vírion/imunologia , Vírion/patogenicidade
6.
PLoS One ; 14(5): e0216713, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31071169

RESUMO

Virus discovery based on high-throughput sequencing relies on enrichment for virus sequences prior to library preparation to achieve a sufficient number of viral reads. In general, preparations of double-stranded RNA or total RNA preparations treated to remove rRNA are used for sequence enrichment. We used virus-specific antibodies to immunocapture virions from plant sap to conduct cDNA synthesis, followed by library preparation and HTS. For the four potato viruses PLRV, PVY, PVA and PYV, template preparation by virion immunocapture provided a simpler and less expensive method than the enrichment of total RNA by ribosomal depletion. Specific enrichment of viral sequences without an intermediate amplification step was achieved, and this high coverage of sequences across the viral genomes was important to identify rare sequence variations. Using this approach, the first complete genome sequence of a potato yellowing virus isolate (PYV, DSMZ PV-0706) was determined in this study. PYV can be confidently assigned as a distinct species in the genus Ilarvirus.


Assuntos
Anticorpos Antivirais , Vírus de Plantas/genética , Vírus de Plantas/imunologia , Vírion/genética , Vírion/imunologia , Animais , Especificidade de Anticorpos , Carlavirus/genética , Carlavirus/imunologia , Biblioteca Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Luteoviridae/genética , Luteoviridae/imunologia , Filogenia , Vírus de Plantas/isolamento & purificação , Potyvirus/genética , Potyvirus/imunologia , RNA Viral/genética , Análise de Sequência de RNA , Solanum tuberosum/virologia , Vírion/isolamento & purificação
8.
Mol Genet Genomics ; 294(4): 887-899, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30923941

RESUMO

In insects, RNAi is considered the major antiviral immune defense pathway. DsRNAs produced during viral infection are processed by Dicer enzymes into small RNAs that function as specificity determinants to silence viral genes. By contrast, in mammals, recognition of molecules associated with viral infection, such as dsRNA, by pattern recognition receptors (PRRs) initiates a signaling cascade that culminates in the production and release of signaling proteins with antiviral function such as interferons. However, in insects, the hypothesis that components of virions can be recognized as pathogen-activated molecular patterns (PAMPs) to activate the innate immune response has not been investigated systematically. In this study, the potential of VP1, that constitutes the major capsid protein of cytoplasmic polyhedrosis virus (CPV; Reoviridae), to activate a collection of immune-related genes was examined in silkworm-derived Bm5 cells. Two different methods of VP1 administration were tested, either through endogenous expression in transformed cell lines, or through addition of purified VP1-based viral-like particles to the extracellular medium. In addition, exposure to CPV virions isolated from purified polyhedra was also performed. In general, our results do not show a robust transcriptional response of immune-related genes to VP1 or CPV virions, but two exceptions were noted. First, the expression of the antimicrobial peptide (AMP) gene Attacin was strongly induced after 24 h of exposure to VP1-based VLPs. Second, the expression levels of dcr-2, an essential gene in the RNAi pathway, were greatly increased in VP1-expressing transformed Sf21 cells but not transformed Bm5 cells, indicating the existence of species-specific effects. However, the increased expression of dcr-2 did not result in increased silencing efficiency when tested in an RNAi reporter assay. Our study indicates that the capsid protein VP1 of CPV has the potential to act as a PAMP and to induce a transcriptional response in insect cells that relate both to RNAi and protein effectors such as AMPs. The identity of the PRRs and the signaling cascade that are potentially triggered by VP1 remain to be elucidated in future experiments. While this study was performed on a small scale, it can encourage more comprehensive studies with high-throughput approaches (microarray, deep sequencing) to search more systematically whether viral capsid proteins can act as PAMPs in insects and whether their production results in the induction of immune-related genes with potential antiviral function.


Assuntos
Bombyx/virologia , Proteínas do Capsídeo/imunologia , Proteínas de Insetos/genética , Reoviridae/metabolismo , Vírion/imunologia , Animais , Bombyx/genética , Bombyx/imunologia , Linhagem Celular , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Imunidade Inata , Padrões Moleculares Associados a Patógenos/imunologia , RNA Helicases/genética , Reoviridae/imunologia , Células Sf9 , Especificidade da Espécie
9.
Nat Immunol ; 20(5): 602-612, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30886418

RESUMO

Despite intense interest in antiviral T cell priming, the routes by which virions move in lymph nodes (LNs) are imperfectly understood. Current models fail to explain how virus-infected cells rapidly appear within the LN interior after viral infection. To better understand virion trafficking in the LN, we determined the locations of virions and infected cells after administration to mice of vaccinia virus or Zika virus. Notably, many rapidly infected cells in the LN interior were adjacent to LN conduits. Through the use of confocal and electron microscopy, we clearly visualized virions within conduits. Functionally, CD8+ T cells rapidly and preferentially associated with vaccinia virus-infected cells in the LN paracortex, which led to T cell activation in the LN interior. These results reveal that it is possible for even large virions to flow through LN conduits and infect dendritic cells within the T cell zone to prime CD8+ T cells.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfonodos/imunologia , Ativação Linfocitária/imunologia , Vírion/imunologia , Animais , Linfócitos T CD8-Positivos/virologia , Feminino , Linfonodos/ultraestrutura , Linfonodos/virologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Vírus Vaccinia/imunologia , Vírus Vaccinia/fisiologia , Vírion/fisiologia , Vírion/ultraestrutura , Viroses/imunologia , Viroses/virologia , Zika virus/imunologia , Zika virus/fisiologia
10.
J Virol ; 93(9)2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30760576

RESUMO

Most individuals are infected with respiratory syncytial virus (RSV) by age two, but infection does not result in long-term protective immunity to subsequent infections. Previous RSV infection may, however, impact responses to an RSV vaccine. The goal of these studies was to explore the effect of previous RSV infection on murine antibody responses to RSV F and G protein-containing virus-like particles (VLP), comparing responses to those resulting from VLP immunization of RSV-naive animals. These studies showed that after RSV infection, immunization with a single dose of VLPs containing a conformation-stabilized prefusion F protein stimulated high titers of neutralizing antibodies (NA), while an immunization with post-F-containing VLPs or a second RSV infection only weakly stimulated NA, even though total anti-F protein IgG antibody levels in both VLP-immunized animals were similar. Furthermore, single pre-F or post-F VLP immunization of animals previously infected (primed) with RSV resulted in total anti-F antibody titers that were 10- to 12-fold higher than titers after a VLP prime and boost of RSV-naive animals or after two consecutive RSV infections. The avidities of serum antibodies as well as numbers of splenic B cells and bone marrow cells after different immunization protocols were also assessed. The combined results show that RSV infection can quite effectively prime animals for the production of protective antibodies that can be efficiently activated by a pre-F VLP boost but not by a post-F VLP boost or a second RSV infection.IMPORTANCE Humans may experience repeated infections caused by the same serotype of respiratory syncytial virus (RSV), in contrast to infections with most other viruses, indicating that immune memory responses to RSV are defective. However, the effects of any residual but nonprotective immunity on responses to RSV vaccines are not clear. This study demonstrates that a VLP vaccine candidate containing a stabilized prefusion F protein can robustly stimulate protective immunity in animals previously infected with RSV, while a second RSV infection or a postfusion F-containing VLP cannot. This result shows that a properly constructed immunogen can be an effective vaccine in animals previously infected with RSV. The results also suggest that the defect in RSV memory is not in the induction of that memory but rather in its activation by a subsequent RSV infection.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Imunoglobulina G/imunologia , Infecções por Vírus Respiratório Sincicial/imunologia , Vírus Sinciciais Respiratórios/imunologia , Proteínas Virais de Fusão/imunologia , Vacinas Virais/imunologia , Vírion/imunologia , Animais , Feminino , Humanos , Imunização Secundária , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Vírus Respiratório Sincicial/genética , Infecções por Vírus Respiratório Sincicial/patologia , Vírus Sinciciais Respiratórios/genética , Células Vero , Proteínas Virais de Fusão/genética , Vacinas Virais/genética , Vírion/genética
11.
Hum Vaccin Immunother ; 15(4): 973-977, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30762467

RESUMO

A quadrivalent split-virion inactivated influenza vaccine (IIV4; Fluzone® Quadrivalent, Sanofi Pasteur) has been available in the US since 2013 for individuals aged ≥ 6 months. Here, we describe the results of an open-label, multicenter trial (WHO Universal Trial Number U1111-1143-8370) evaluating the immunogenicity and safety of IIV4 in Indian children aged 6-35 months and 3-8 years, adolescents aged 9-17 years, and adults aged ≥ 18 years (n = 100 per group). Post-vaccination hemagglutination inhibition titers for all strains in all age groups were ≥ 8 fold higher than at baseline (range, 8-51). At least 70% of participants in all age groups seroconverted or had a significant increase in titer for each strain. The most common solicited reactions were injection-site pain and tenderness, plus fever in participants 6-23 months and myalgia in older children and adolescents. All injection-site reactions and most systemic reactions were grade 1 or 2 and resolved within 3 days. Only three vaccine-related unsolicited adverse events were reported, all of which were grade 1 or 2 and transient. No immediate adverse events, adverse events leading to study discontinuation, adverse events of special interest, or serious adverse events were reported. This study showed that IIV4 was well tolerated and highly immunogenic in all age groups. This adds important data on the safety, tolerability, and immunogenicity of influenza vaccines in India.


Assuntos
Anticorpos Antivirais/sangue , Imunogenicidade da Vacina , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Injeções Intramusculares , Vírion/imunologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Índia , Lactente , Influenza Humana/prevenção & controle , Masculino , Vacinação/métodos , Vacinas de Produtos Inativados/imunologia , Adulto Jovem
12.
J Virol ; 93(6)2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30626669

RESUMO

Human cytomegalovirus (HCMV) is the most frequent viral cause of congenital infections that can lead to severe birth defects. Although HCMV is frequently detected in semen and thus is potentially sexually transmitted, the role of semen in HCMV transmission is largely unclear. Here we describe that human seminal plasma (SP; the cell-free supernatant of semen) inhibits HCMV infection. The inhibition of HCMV infection was dose dependent and effective for different cell types, virus strains, and semen donors. This inhibitory effect was specific for HCMV, as herpes simplex virus 2 (HSV-2) and human immunodeficiency virus type 1 (HIV-1) infections were enhanced by SP. Mechanistically, SP inhibited infection by interfering with the attachment of virions to cells most likely via an interaction with the trimeric glycoprotein complex gH/gL/gO. Together, our findings suggest that semen contains a factor that potentially limits sexual transmission of HCMV.IMPORTANCE The role of semen in sexual transmission of human cytomegalovirus (HCMV) is currently unclear. This is surprising, as HCMV is frequently detected in this body fluid and infection is of high danger for neonates and pregnant women. In this study, we found that seminal plasma (SP) dose dependently inhibited HCMV infection. The infection inhibition was specific for HCMV, as other viruses, such as human immunodeficiency virus type 1 (HIV-1) and herpes simplex virus 2 (HSV-2), were not inhibited by SP. SP must contain a soluble, heat-resistant factor that limits attachment of HCMV particles to cells, probably by interaction with the trimeric glycoprotein complex gH/gL/gO. This novel virus-host interaction could possibly limit transmission of HCMV via semen during sexual intercourse.


Assuntos
Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Sêmen/imunologia , Sêmen/virologia , Células Cultivadas , Infecções por Citomegalovirus/virologia , Células Epiteliais/imunologia , Células Epiteliais/virologia , Fibroblastos/imunologia , Fibroblastos/virologia , Humanos , Vírion/imunologia
13.
Proc Natl Acad Sci U S A ; 116(5): 1739-1744, 2019 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-30642966

RESUMO

The biological characteristics of HIV pose serious difficulties for the success of a preventive vaccine. Molecularly cloned SIVmac239 is difficult for antibodies to neutralize, and a variety of vaccine approaches have had great difficulty achieving protective immunity against it in rhesus monkey models. Here we report significant protection against i.v. acquisition of SIVmac239 using a long-lasting approach to vaccination. The vaccine regimen includes a replication-competent herpesvirus engineered to contain a near-full-length SIV genome that expresses all nine SIV gene products, assembles noninfectious SIV virion particles, and is capable of eliciting long-lasting effector-memory cellular immune responses to all nine SIV gene products. Vaccinated monkeys were significantly protected against acquisition of SIVmac239 following repeated marginal dose i.v. challenges over a 4-month period. Further work is needed to define the critical components necessary for eliciting this protective immunity, evaluate the breadth of the protection against a variety of strains, and explore how this approach may be extended to human use.


Assuntos
Vacinas contra a SAIDS/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Células Cultivadas , Herpesviridae/imunologia , Macaca mulatta , Vacinação/métodos , Vírion/imunologia , Replicação Viral/imunologia
14.
PLoS One ; 14(1): e0210553, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30650163

RESUMO

Enterovirus 71 (EV71) has emerged as a neurological virus causing life-threatening diseases in young children and infants. Although EV71 vaccines in development have presented promising results in several clinical trials, the identified key antigen for improving the broad protective efficacy of EV71 vaccines has not been well investigated. In this report, we show that different multiplicities of infection (MOIs) of the B4(E59) virus significantly affect EV71 vaccine production in a serum-free microcarrier bioreactor system. The antigens produced from high MOIs of 10-1 and 10-2 exhibited higher yield and more infectious full particle (FP) contents in the EV71 vaccines than those produced with low MOIs of 10-4 and 10-6, leading to better cross-neutralizing efficacy. The C4(E36) neutralization results showed that only antisera raised from EV71 FPs provided substantial neutralizing titers against C4(E36), whereas empty particles (EPs) of EV71 conferred no efficacy. Competitive ELISA showed that anti-FP mainly binds to FPs and that 20% of antibodies bind to EPs, whereas most anti-EP binds EPs, with only 10% antibodies binding to FPs. VP1-adsorbed anti-FP lost most of the virus neutralization efficiency, suggesting that the VP1 subunit of FP is the major immunogenic antigen determining the ability of the EV71 vaccine to elicit cross-neutralizing antibodies against EV71 virus subtypes. These findings demonstrate that the high-MOI production approach is significantly correlated with FP productivity, thereby improving the cross-neutralization efficacy of an EV71 vaccine and providing the basis for a better vaccine design against widespread EV71 viruses.


Assuntos
Anticorpos Neutralizantes/biossíntese , Enterovirus/genética , Enterovirus/imunologia , Vírion/imunologia , Animais , Especificidade de Anticorpos , Enterovirus/ultraestrutura , Genótipo , Humanos , Camundongos Endogâmicos BALB C , Testes de Neutralização , Células Vero , Vacinas Virais/imunologia , Vírion/ultraestrutura
15.
J Virol ; 93(7)2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30651356

RESUMO

Human respiratory syncytial virus (RSV) is a major pediatric respiratory pathogen. The attachment (G) and fusion (F) glycoproteins are major neutralization and protective antigens. RSV G is expressed as membrane-anchored (mG) and -secreted (sG) forms, both containing a central fractalkine-like CX3C motif. The CX3C motif and sG are thought to interfere with host immune responses and have been suggested to be omitted from a vaccine. We used a chimeric bovine/human parainfluenza virus type 3 (rB/HPIV3) vector to express RSV wild-type (wt) G and modified forms, including sG alone, mG alone, mutants with ablated CX3C, and G with enhanced packaging into vector virions. In hamsters, these viruses replicated to similar titers. When assayed with a complement-enhanced neutralization assay in Vero cells, sG did not reduce the serum RSV- or PIV3-neutralizing antibody (NAb) responses, whereas ablating CX3C drastically reduced the RSV NAb response. Protective efficacy against RSV challenge was not reduced by sG but was strongly dependent on the CX3C motif. In ciliated human airway epithelial (HAE) cells, NAbs induced by wt G, but not by wt F, completely blocked RSV infection in the absence of added complement. This activity was dependent on the integrity of the CX3C motif. In hamsters, the rB/HPIV3 expressing wt G conferred better protection against RSV challenge than that expressing wt F. Codon optimization of the wt G further increased its immunogenicity and protective efficacy. This study showed that ablation of the CX3C motif or sG in an RSV vaccine, as has been suggested previously, would be ill advised.IMPORTANCE Human RSV is the leading viral cause of severe pediatric respiratory illness. An RSV vaccine is not yet available. The RSV attachment protein G is an important protective and neutralization antigen. G contains a conserved fractalkine-like CX3C motif and is expressed in mG and sG forms. sG and the CX3C motif are thought to interfere with host immune responses, but this remains poorly characterized. Here, we used an attenuated chimeric bovine/human parainfluenza virus type 3 (rB/HPIV3) vector to express various modified forms of RSV G. We demonstrated that strong antibody and protective responses could be induced by G alone, and that this was highly dependent on the integrity of the CX3C motif. There was no evidence that sG or the CX3C motif impaired immune responses against RSV G or the rB/HPIV3 vector. rB/HPIV3 expressing wt RSV G provides a bivalent vaccine against RSV and HPIV3.


Assuntos
Vetores Genéticos/imunologia , Infecções por Vírus Respiratório Sincicial/imunologia , Vírus Sincicial Respiratório Humano/imunologia , Respirovirus/imunologia , Proteínas do Envelope Viral/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Bovinos , Criança , Feminino , Humanos , Macaca mulatta , Mesocricetus , Infecções por Vírus Respiratório Sincicial/virologia , Células Vero , Proteínas Virais de Fusão/imunologia , Vírion/imunologia , Replicação Viral/imunologia
16.
Nat Commun ; 10(1): 78, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30622256

RESUMO

Antibodies against the Membrane-Proximal External Region (MPER) of the Env gp41 subunit neutralize HIV-1 with exceptional breadth and potency. Due to the lack of knowledge on the MPER native structure and accessibility, different and exclusive models have been proposed for the molecular mechanism of MPER recognition by broadly neutralizing antibodies. Here, accessibility of antibodies to the native Env MPER on single virions has been addressed through STED microscopy. STED imaging of fluorescently labeled Fabs reveals a common pattern of native Env recognition for HIV-1 antibodies targeting MPER or the surface subunit gp120. In the case of anti-MPER antibodies, the process evolves with extra contribution of interactions with the viral lipid membrane to binding specificity. Our data provide biophysical insights into the recognition of the potent and broadly neutralizing MPER epitope on HIV virions, and as such is of importance for the design of therapeutic interventions.


Assuntos
Anticorpos Neutralizantes/metabolismo , Anticorpos Anti-HIV/metabolismo , Proteína gp41 do Envelope de HIV/metabolismo , HIV-1/imunologia , Ligação Proteica/imunologia , Anticorpos Neutralizantes/imunologia , Epitopos/química , Epitopos/imunologia , Corantes Fluorescentes/química , Células HEK293 , Anticorpos Anti-HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , Humanos , Processamento de Imagem Assistida por Computador , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/imunologia , Fragmentos Fab das Imunoglobulinas/metabolismo , Microscopia de Fluorescência/métodos , Vírion/imunologia , Vírion/metabolismo
17.
Cell Mol Life Sci ; 76(1): 67-87, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30324425

RESUMO

In contrast to the insidious and poorly immunogenic human papillomavirus (HPV) infections, vaccination with the HPV virus-like particles (vlps) is non-infectious and stimulates a strong neutralizing-antibody response that protects HPV-naïve vaccinees from viral infection and associated cancers. However, controversy about alleged adverse events following immunization (AEFI) with the vlps have led to extensive reductions in vaccine acceptance, with countries like Japan dropping it altogether. The AEFIs are grouped into chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). In this review, we present a hypothesis that the AEFIs might arise from malfunctions within the immune system when confronted with the unusual antigen. In addition, we outline how the pathophysiology of the AEFIs can be cost-effectively investigated with the holistic principles of systems vaccinology in a two-step process. First, comprehensive immunological profiles of HPV vaccinees exhibiting the AEFIs are generated by integrating the data derived from serological profiling for prominent HPV antibodies and serum cytokines, with data from serum metabolomics, peripheral white blood cells transcriptomics and gut microbiome profiling. Next, the immunological profiles are compared with corresponding profiles generated for matched (a) HPV vaccinees without AEFIs; (b) non-HPV-vaccinated individuals with CFS/ME-like symptoms; and (c) non-HPV-vaccinated individuals without CFS/ME. In these comparisons, any causal links between HPV vaccine and the AEFIs, as well as the underlying molecular basis for the links will be revealed. Such a study should provide an objective basis for evaluating HPV vaccine safety and for identifying biomarkers for individuals at risk of developing AEFI with HPV vaccination.


Assuntos
Biologia Computacional/métodos , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/efeitos adversos , Vacinação/efeitos adversos , Animais , Humanos , Imunogenicidade da Vacina , Papillomaviridae/imunologia , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/imunologia , Vacinas contra Papillomavirus/imunologia , Vacinas contra Papillomavirus/uso terapêutico , Vacinação/métodos , Vacinologia/métodos , Vírion/imunologia
18.
Vaccine ; 37(2): 258-264, 2019 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-30497837

RESUMO

INTRODUCTION: Shortages of vaccine supplies repeatedly occur, limiting our abilities to prevent influenza. Therefore, increasing production volume remains a priority. The presently licensed seasonal influenza vaccines contain 15 µg of viral hemagglutinin per strain in adult, and up to 60 µg in elderly patients. Decreasing the amount of viral parts while maintaining efficacy is one way of increasing production capacity. METHODS: This was multicenter, stratified (18-60 years and >60 years of age), prospective, randomized, double-blind, active-controlled, parallel-arm, non-inferiority clinical trial, conducted in the European Union, involving 1206 patients. We used hemagglutination inhibition assay to assess the immunogenicity of a newly developed, whole virion, seasonal trivalent influenza vaccine, containing 6 µg hemagglutinin per strain (FluArt, Hungary) and to assess whether it is non-inferior to the presently licensed vaccine containing 15 µg hemagglutinin per strain. Safety and tolerability of both vaccines were assessed based on EMEA guidelines. RESULTS: The reduced dose vaccine containing 6 µg of hemagglutinin per strain was safe and non-inferior to the currently licensed 15 µg vaccine, not only in adult, but also in elderly patients, according to the immunogenicity criteria by the FDA and EMEA (seroconversion, seroprotection and post/pre vaccination GMT ratios), and it fulfilled all applicable licensing requirements for both age groups. CONCLUSIONS: Based on the results, the reduced dose vaccine was licensed in the EU member state Hungary and safely administered in over 1.5 million cases so far. The amount of viral hemagglutinin needed can be reduced by using a whole virion vaccine with aluminum phosphate adjuvants. REGISTRATION: This study was registered by the European Clinical Trials Database, EudraCT, number: 2011-003314-16.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Alumínio/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Adolescente , Adulto , Idoso , Alumínio/administração & dosagem , Anticorpos Antivirais/imunologia , Formas de Dosagem , Método Duplo-Cego , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Imunogenicidade da Vacina , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/administração & dosagem , Licenciamento , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Vacinação/métodos , Vírion/imunologia , Adulto Jovem
19.
Methods Mol Biol ; 1911: 441-450, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30593644

RESUMO

Hepatitis C virus (HCV) pseudoparticles (HCVpp) are generated by cotransfection of HCV envelope (E1 and E2) genes along with a retroviral packaging/reporter construct into HEK293T cells. Enveloped particles bearing HCV E1E2 proteins on their surface are released through a retroviral budding process into the supernatant. Viral E1E2 glycoproteins facilitate a single round of receptor-mediated entry of HCVpp into hepatoma cells, which can be quantified by reporter gene expression. These HCVpp have been employed to study mechanisms of HCV entry into hepatoma cells, as well as HCV neutralization by immune sera or HCV-specific monoclonal antibodies.


Assuntos
Anticorpos Anti-Hepatite C/imunologia , Hepatite C/imunologia , Testes de Neutralização/métodos , Internalização do Vírus , Anticorpos Monoclonais/sangue , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Linhagem Celular Tumoral , Genes Reporter/genética , Células HEK293 , Hepacivirus/imunologia , Hepatite C/sangue , Hepatite C/virologia , Anticorpos Anti-Hepatite C/sangue , Humanos , Testes de Neutralização/instrumentação , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Vírion/imunologia , Liberação de Vírus/imunologia
20.
Front Immunol ; 9: 2876, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30574147

RESUMO

Antiviral restriction factors are host cellular proteins that constitute a first line of defense blocking viral replication and propagation. In addition to interfering at critical steps of the viral replication cycle, some restriction factors also act as innate sensors triggering innate responses against infections. Accumulating evidence suggests an additional role for restriction factors in promoting antiviral cellular immunity to combat viruses. Here, we review the recent progress in our understanding on how restriction factors, particularly APOBEC3G, SAMHD1, Tetherin, and TRIM5α have the cell-autonomous potential to induce cellular resistance against HIV-1 while promoting antiviral innate and adaptive immune responses. Also, we provide an overview of how these restriction factors may connect with protein degradation pathways to modulate anti-HIV-1 cellular immune responses, and we summarize the potential of restriction factors-based therapeutics. This review brings a global perspective on the influence of restrictions factors in intrinsic, innate, and also adaptive antiviral immunity opening up novel research avenues for therapeutic strategies in the fields of drug discovery, gene therapy, and vaccines to control viral infections.


Assuntos
Infecções por HIV/imunologia , HIV-1/imunologia , Interações Hospedeiro-Patógeno/imunologia , Imunidade Celular , Desaminase APOBEC-3G/imunologia , Desaminase APOBEC-3G/metabolismo , Imunidade Adaptativa , Antígenos CD/imunologia , Antígenos CD/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Proteínas de Transporte/imunologia , Proteínas de Transporte/metabolismo , Proteínas Ligadas por GPI/imunologia , Proteínas Ligadas por GPI/metabolismo , Infecções por HIV/virologia , HIV-1/patogenicidade , Humanos , Imunidade Inata , Proteólise , RNA Viral/metabolismo , Proteína 1 com Domínio SAM e Domínio HD/imunologia , Proteína 1 com Domínio SAM e Domínio HD/metabolismo , Vírion/imunologia , Replicação Viral/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA