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1.
Cell Prolif ; 53(1): e12721, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31782850

RESUMO

OBJECTIVES: Secondary bacterial pneumonia is common following influenza infection. However, it remains unclear about the underlying molecular mechanisms. MATERIALS AND METHODS: We established a mouse model of post-influenza S aureus pneumonia using conditional Shp2 knockout mice (LysMCre/+ :Shp2flox/flox ). The survival, bacterial clearance, pulmonary histology, phenotype of macrophages, and expression of type I interferons and chemokines were assessed between SHP2 deletion and control mice (Shp2flox/flox ). We infused additional KC and MIP-2 to examine the reconstitution of antibacterial immune response in LysMCre/+ :Shp2flox/flox mice. The effect of SHP2 on signal molecules including MAPKs (JNK, p38 and Erk1/2), NF-κB p65 and IRF3 was further detected. RESULTS: LysMCre/+ :Shp2flox/flox mice displayed impaired antibacterial immunity and high mortality compared with control mice in post-influenza S aureus pneumonia. The attenuated antibacterial ability was associated with the induction of type I interferon and suppression of chemo-attractants KC and MIP-2, which reduced the infiltration of neutrophils into the lung upon secondary bacterial invasion. In additional, Shp2 knockout mice displayed enhanced polarization to alternatively activated macrophages (M2 phenotype). Further in vitro analyses consistently demonstrated that SHP2-deficient macrophages were skewed towards an M2 phenotype and had a decreased antibacterial capacity. Moreover, SHP2 modulated the inflammatory response to secondary bacterial infection via interfering with NF-κB and IRF3 signalling in macrophages. CONCLUSIONS: Our findings reveal that the SHP2 expression enhances the host immune response and prompts bacterial clearance in post-influenza S aureus pneumonia.


Assuntos
Vírus da Influenza A/imunologia , Macrófagos/imunologia , Infecções por Orthomyxoviridae/imunologia , Pneumonia Estafilocócica/imunologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/deficiência , Staphylococcus aureus/imunologia , Animais , Inflamação/genética , Inflamação/imunologia , Inflamação/patologia , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/imunologia , Macrófagos/patologia , Camundongos , Camundongos Transgênicos , NF-kappa B/genética , NF-kappa B/imunologia , Infecções por Orthomyxoviridae/complicações , Infecções por Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/patologia , Pneumonia Estafilocócica/etiologia , Pneumonia Estafilocócica/genética , Pneumonia Estafilocócica/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/imunologia
2.
J Pharm Biomed Anal ; 177: 112876, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31525575

RESUMO

Flavonoids-enriched extract from Scutellaria baicalensis roots (FESR) ameliorated influenza A virus (IAV) induced acute lung injury (ALI) in mice by inhibiting the excessive activation of complement system in vivo. However, FESR had no anti-complementary activity in vitro. In order to reveal the effective materials of FESR for the treatment of IAV-induced ALI, the present research explored the metabolic process of FESR both in nomal and IAV infected mice by the method of UHPLC-ESI-LTQ/MS, as well as the metabolic activating mechanism. The results showed that the inactive flavonoid glycosides of FESR were partly metabolized into anti-complementary aglycones in vivo, mainly including 5,7,4'-trihydroxy-8-methoxy-flavone, norwogonin, baicalein, wogonin, oroxylin A and chrysin. Moreover, compared with the normal mice, IAV-induced ALI mice exhibited more efficient on producing and absorbing these active metabolites, with AUC0-t and Cmax in plasma and concentrations in lungs and intestines markedly elevated in the IAV treated groups (P <  0.05). Interestingly, the intestinal bacteria from IAV-induced ALI mice showed stronger ß-glucuronidase activity and also had higher efficiency on transforming FESR to the flavonoid aglycones. These findings suggested that the anti-complementary aglycones produced by metabolic activation in vivo should be the potential effective materials of FESR against IAV infections, and intestinal bacteria might play an important role on the higher bioavailability of FESR in IAV infected mice. Additionally, the animals under the pathological state are more suitable for the metabolic study of traditional Chinese medicine.


Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Inativadores do Complemento/farmacocinética , Medicamentos de Ervas Chinesas/farmacocinética , Flavonoides/farmacocinética , Influenza Humana/tratamento farmacológico , Scutellaria baicalensis/química , Ativação Metabólica , Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/virologia , Animais , Inativadores do Complemento/administração & dosagem , Inativadores do Complemento/química , Modelos Animais de Doenças , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/química , Flavonoides/administração & dosagem , Microbioma Gastrointestinal/fisiologia , Glucuronidase/metabolismo , Humanos , Vírus da Influenza A/imunologia , Vírus da Influenza A/patogenicidade , Influenza Humana/metabolismo , Influenza Humana/virologia , Pulmão/patologia , Camundongos , Raízes de Plantas/química , Organismos Livres de Patógenos Específicos
3.
Acta Virol ; 63(4): 347-365, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31802678

RESUMO

Influenza A viruses (IAVs) cause yearly repeating infections in humans. The current vaccination approach is based on the production of virus-neutralizing antibodies. Virus-neutralizing antibodies, however, are closely strain-specific due to the IAV variability. Therefore, antibodies produced during the previous influenza season do not provide sufficient protection against new infection, and, hence, annual revaccination is needed. The utilization of the influenza conserved stem domain of hemagglutinin (HA), the HA2 gp, led to a new vaccine design based on cross-reactive cellular and especially humoral immune responses represented by HA2-specific antibodies. The HA2-specific antibodies exhibit cross-reactivity with HA2 gp within one subtype or even among subtypes and play a role in protective immunity against influenza infection. There are several elimination mechanisms of viral replication mediated by HA2-specific antibodies. After recognition of the epitope, they prevent the conformational rearrangement of HA or the insertion of the fusion protein into the endosomal membrane and, consequently, the fusion pore formation. In this case, no release of viral genetic information into the target cell is enabled and virus cannot replicate. The HA2-specific antibodies are involved in the elimination of pathogen via the Fc fragment by activation of the cytotoxic mechanisms of innate immunity as are the antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent phagocytosis (ADP), or complement-dependent cytotoxicity (CDC), resulting in virus elimination and earlier recovery of the host from the infection. Though the protective effect of HA2-specific antibodies on the course of IAV infection was shown, few cases of worsening of IAV infection mediated by HA2-specific antibodies have been described. The identification of antigenic epitopes on HA2 gp that induce antibodies with such deteriorating effect on influenza infection can help to eliminate the unsuitable epitopes of HA2 gp as immunogens during the design of heteroprotective vaccine against influenza and can remove the side effects linked with the observations mentioned above. Keywords: influenza A virus; HA2 stem domain of hemagglutinin; immunization strategies; HA2-specific antibodies.


Assuntos
Anticorpos Antivirais , Vírus da Influenza A , Influenza Humana , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia
4.
PLoS Pathog ; 15(12): e1008155, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31856218

RESUMO

Cellular response to environmental challenges requires immediate and precise regulation of transcriptional programs. During viral infections, this includes the expression of antiviral genes that are essential to combat the pathogen. Transcribed mRNAs are bound and escorted to the cytoplasm by the cap-binding complex (CBC). We recently identified a protein complex consisting of NCBP1 and NCBP3 that, under physiological conditions, has redundant function to the canonical CBC, consisting of NCBP1 and NCBP2. Here, we provide evidence that NCBP3 is essential to mount a precise and appropriate antiviral response. Ncbp3-deficient cells allow higher virus growth and elicit a reduced antiviral response, a defect happening on post-transcriptional level. Ncbp3-deficient mice suffered from severe lung pathology and increased morbidity after influenza A virus challenge. While NCBP3 appeared to be particularly important during viral infections, it may be more broadly involved to ensure proper protein expression.


Assuntos
Infecções por Orthomyxoviridae/imunologia , Proteínas de Ligação ao Cap de RNA/imunologia , Proteínas de Ligação ao Cap de RNA/metabolismo , Animais , Vírus da Influenza A/imunologia , Camundongos , Camundongos Knockout , Infecções por Orthomyxoviridae/metabolismo , Biossíntese de Proteínas/fisiologia
5.
Vet Microbiol ; 239: 108492, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31767065

RESUMO

Swine influenza A virus (IAV-S) infections are a major cause of economic losses for the swine industry. The vast genetic and antigenic diversity often results in mismatch between the vaccine and field strains, necessitating frequent updates of vaccines. Inactivated IAV-S vaccines are of questionable efficacy. Intra-nasally administered live vaccines are more effective but are associated with safety concerns. The objective of this study was to develop a first-generation vaccine which combines the safety and efficacy advantages of inactivated and attenuated vaccines respectively. The approach targeted fragmentation of viral nucleic acids while preserving structure. Hence, cultures of influenza A/CA/04/09 H1N1 were exposed to 44 °C for 10 min. to reversibly denature the capsid, followed by RNase treatment to digest the genomic RNA and then refolded at lower temperatures. As targeted, treated virions retained an intact structure and were not detected in the first passage in infected cells. To improve intra-nasal delivery of the vaccine antigen, the vaccine antigen was delivered in porcine lung surfactant. Both the treated vaccine alone or vaccine in combination with the surfactant elicited strong anti-HA and virus neutralizing antibodies, protection against viral shedding and lung lesions in 3-week-old piglets. There were no significant differences between the groups. Vaccine viral replication was not detected in the vaccinated pigs. The described approach can advance current immunization practices against swine influenza viruses due to the relative simplicity, high efficacy and safety and ease of adaptation to newly emerging field strains.


Assuntos
Vírus da Influenza A/imunologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/veterinária , Tensoativos/administração & dosagem , Vacinas Atenuadas/imunologia , Vacinas de Produtos Inativados/imunologia , Administração Intranasal/veterinária , Animais , Anticorpos Antivirais/sangue , Temperatura Alta , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/virologia , Suínos , Doenças dos Suínos/prevenção & controle , Doenças dos Suínos/virologia , Vacinas Atenuadas/administração & dosagem , Vacinas de Produtos Inativados/administração & dosagem
6.
J Immunol Res ; 2019: 8028725, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31612153

RESUMO

Influenza virus infection is a serious threat to humans and animals, with the potential to cause severe pneumonia and death. Annual vaccination strategies are a mainstay to prevent complications related to influenza. However, protection from the emerging subtypes of influenza A viruses (IAV) even in vaccinated individuals is challenging. Innate immune cells are the first cells to respond to IAV infection in the respiratory tract. Virus replication-induced production of cytokines from airway epithelium recruits innate immune cells to the site of infection. These leukocytes, namely, neutrophils, monocytes, macrophages, dendritic cells, eosinophils, natural killer cells, innate lymphoid cells, and γδ T cells, become activated in response to IAV, to contain the virus and protect the airway epithelium while triggering the adaptive arm of the immune system. This review addresses different anti-influenza virus schemes of innate immune cells and how these cells fine-tune the balance between immunoprotection and immunopathology during IAV infection. Detailed understanding on how these innate responders execute anti-influenza activity will help to identify novel therapeutic targets to halt IAV replication and associated immunopathology.


Assuntos
Vírus da Influenza A/imunologia , Influenza Humana/imunologia , Leucócitos/virologia , Citocinas , Células Dendríticas/imunologia , Células Dendríticas/virologia , Humanos , Imunidade Inata , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/virologia , Leucócitos/imunologia , Macrófagos/imunologia , Macrófagos/virologia , Monócitos/imunologia , Monócitos/virologia , Replicação Viral/imunologia
7.
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
8.
Nat Commun ; 10(1): 4624, 2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604929

RESUMO

Cytosolic mitochondrial DNA (mtDNA) activates cGAS-mediated antiviral immune responses, but the mechanism by which RNA viruses stimulate mtDNA release remains unknown. Here we show that viroporin activity of influenza virus M2 or encephalomyocarditis virus (EMCV) 2B protein triggers translocation of mtDNA into the cytosol in a MAVS-dependent manner. Although influenza virus-induced cytosolic mtDNA stimulates cGAS- and DDX41-dependent innate immune responses, the nonstructural protein 1 (NS1) of influenza virus associates with mtDNA to evade the STING-dependent antiviral immunity. The STING-dependent antiviral signaling is amplified in neighboring cells through gap junctions. In addition, we find that STING-dependent recognition of influenza virus is essential for limiting virus replication in vivo. Our results show a mechanism by which influenza virus stimulates mtDNA release and highlight the importance of DNA sensing pathway in limiting influenza virus replication.


Assuntos
DNA Mitocondrial/imunologia , Vírus da Influenza A/imunologia , Proteínas da Matriz Viral/imunologia , Proteínas Virais/imunologia , Transporte Ativo do Núcleo Celular , Núcleo Celular/metabolismo , Citosol/metabolismo , DNA Mitocondrial/metabolismo , Vírus da Encefalomiocardite/imunologia , Células HEK293 , Interações entre Hospedeiro e Microrganismos , Humanos , Imunidade Inata , Transdução de Sinais , Proteínas Virais/metabolismo
9.
J Biomed Sci ; 26(1): 76, 2019 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-31629405

RESUMO

The influenza A virus was isolated for the first time in 1931, and the first attempts to develop a vaccine against the virus began soon afterwards. In addition to causing seasonal epidemics, influenza viruses can cause pandemics at random intervals, which are very hard to predict. Vaccination is the most effective way of preventing the spread of influenza infection. However, seasonal vaccination is ineffective against pandemic influenza viruses because of antigenic differences, and it takes approximately six months from isolation of a new virus to develop an effective vaccine. One of the possible ways to fight the emergence of pandemics may be by using a new type of vaccine, with a long and broad spectrum of action. The extracellular domain of the M2 protein (M2e) of influenza A virus is a conservative region, and an attractive target for a universal influenza vaccine. This review gives a historical overview of the study of M2 protein, and summarizes the latest developments in the preparation of M2e-based universal influenza vaccines.


Assuntos
Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Proteínas da Matriz Viral/imunologia , História do Século XX , História do Século XXI , Humanos
10.
Biomed Res Int ; 2019: 4643260, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31531353

RESUMO

Background: Yearly influenza epidemics have considerable effects on public health worldwide. The 2017-2018 influenza season in Italy was of greater severity than previous seasons. The aim of this study was to describe the 2017-2018 influenza season in Southern Italy and the molecular characteristics of the circulating viral strains. Methods: The incidence of influenza-like illness (ILI) was analysed. Nasopharyngeal swabs collected from patients with ILI from week 46/2017 to week 17/2018 were tested to identify influenza A viruses (IAV) and influenza B viruses (IBV). Sequencing and phylogenetic analysis of haemagglutinin genes were also performed on 73 positive samples (35 IBV, 36 IAV H1, and 2 IAV H3 strains). Results: During the 2017-2018 season, the peak incidence was 14.32 cases per 1,000 inhabitants. IBV strains were identified in 71.0% of cases. The 35 characterised IBV strains belonged to Yamagata lineage clade 3, the 36 A/H1N1pdm09 strains clustered with the genetic subgroup 6B.1, and the 2 A/H3N2 strains clustered with the genetic subgroup 3C.2a. Intensive-care unit (ICU) admission was required in 50 cases of acute respiratory distress syndrome (ARDS). Among the >64-year age group, 18 out of 26 ICU-ARDS cases (69.2%) were caused by IBV, and 14 of these (77.8%) were B/Yamagata lineage. Conclusions: The 2017-2018 influenza season was one of the most severe in a decade in Southern Italy. IBV mismatch between the trivalent vaccine and the circulating strains occurred. The high number of ICU-ARDS cases caused by B/Yamagata strains in the >64-year age group suggests that further data on the effectiveness of the available influenza vaccines are needed to determine the best way to protect the elderly against both IBV lineages.


Assuntos
Vírus da Influenza A/genética , Vírus da Influenza B/genética , Influenza Humana/epidemiologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Vírus da Influenza A/imunologia , Vírus da Influenza B/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Filogenia , Saúde Pública , Estações do Ano , Adulto Jovem
11.
mSphere ; 4(5)2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31511367

RESUMO

Serological assays are used to diagnose and characterize host immune responses against microbial pathogens. Microarray technologies facilitate high-throughput immunoassays of antibody detection against multiple pathogens simultaneously. To improve survey of influenza A virus (IAV), influenza B virus (IBV), respiratory syncytial virus (RSV), and adenovirus (AdV) antibody levels, we developed a microarray consisting of IAV H1N1, IAV H1N1pdm09 (vaccine), IAV H3N2, IBV Victoria, IBV Yamagata, RSV, AdV type 5 hexon protein, and control antigens printed on the bottom of a microtiter plate well. Bound IgG antibodies were detected with anti-human IgG-coated photon-upconverting nanoparticles and measured with a photoluminescence imager. The performance of the microarray immunoassay (MAIA) was evaluated with serum samples (n = 576) collected from children (n = 288) at 1 and 2 years of age and tested by standard enzyme immunoassays (EIAs) for antibodies to IAV vaccine and RSV. EIAs and MAIA showed substantial to almost perfect agreement (Cohen's κ, 0.62 to 0.83). Applying MAIA, we found seroprevalences of 55% for IAV H1N1, 54% for IAV vaccine, 30% for IAV H3N2, 24% for IBV Victoria, 25% for IBV Yamagata, 38% for RSV, and 26% for AdV in 1-year-old children (n = 768). By the age of 2 years, IgG seropositivity rates (n = 714) increased to 74% for IAV H1N1, 71% for IAV vaccine, 49% for IAV H3N2, 47% for IBV Yamagata, 49% for IBV Victoria, 68% for RSV, and 58% for AdV. By analyzing increases in antibody levels not biased by vaccinations, we found a reinfection rate of 40% for RSV and 31% for AdV in children between 1 and 2 years of age.IMPORTANCE The multiplex immunoassay was successfully used to simultaneously detect antibodies against seven different viruses. The developed serological microarray is a new promising tool for diagnostic, epidemiological, and seroprevalence analyses of virus infections.


Assuntos
Anticorpos Antivirais/sangue , Ensaios de Triagem em Larga Escala/métodos , Infecções Respiratórias/virologia , Testes Sorológicos/métodos , Vírus/imunologia , Adenoviridae/imunologia , Pré-Escolar , Estudos de Coortes , Humanos , Imunoensaio/métodos , Lactente , Vírus da Influenza A/imunologia , Vírus da Influenza B/imunologia , Análise em Microsséries , Estudos Observacionais como Assunto , Vírus Sinciciais Respiratórios/imunologia , Infecções Respiratórias/imunologia
12.
PLoS Pathog ; 15(9): e1008077, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31557273

RESUMO

Influenza A virus (IAV) is a seasonal pathogen with the potential to cause devastating pandemics. IAV infects multiple epithelial cell subsets in the respiratory tract, eliciting damage to the lungs. Clearance of IAV is primarily dependent on CD8+ T cells, which must balance control of the infection with immunopathology. Using a virus expressing Cre recombinase to permanently label infected cells in a Cre-inducible reporter mouse, we previously discovered infected club cells that survive both lytic virus replication and CD8+ T cell-mediated clearance. In this study, we demonstrate that ciliated epithelial cells, type I and type II alveolar cells can also become survivor cells. Survivor cells are stable in the lung long-term and demonstrate enhanced proliferation compared to uninfected cells. When we investigated how survivor cells evade CD8+ T cell killing we observed that survivor cells upregulated the inhibitory ligand PD-L1, but survivor cells did not use PD-L1 to evade CD8+ T cell killing. Instead our data suggest that survivor cells are not inherently resistant to CD8+ T cell killing, but instead no longer present IAV antigen and cannot be detected by CD8+ T cells. Finally, we evaluate the failure of CD8+ T cells to kill these previously infected cells. This work demonstrates that additional cell types can survive IAV infection and that these cells robustly proliferate and are stable long term. By sparing previously infected cells, the adaptive immune system may be minimizing pathology associated with IAV infection.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Evasão da Resposta Imune , Influenza Humana/imunologia , Influenza Humana/virologia , Imunidade Adaptativa , Animais , Antígeno B7-H1/imunologia , Proliferação de Células , Sobrevivência Celular/imunologia , Citotoxicidade Imunológica , Humanos , Imunidade Celular , Vírus da Influenza A/imunologia , Vírus da Influenza A/patogenicidade , Influenza Humana/patologia , Pulmão/imunologia , Pulmão/patologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptor de Morte Celular Programada 1/imunologia
13.
Influenza Other Respir Viruses ; 13(5): 504-516, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31411006

RESUMO

BACKGROUND: Formulation of neuraminidase (NA) within influenza vaccines is gaining importance in light of recent human studies. The enzyme-linked lectin assay (ELLA) is considered a reliable assay to evaluate human anti-NA antibodies. OBJECTIVES: To overcome interference by hemagglutinin (HA)-specific antibodies and detect neuraminidase inhibitory (NI) antibodies only, two different sources of antigen have been studied in ELLA: reassortant viruses with a mismatched avian origin-HA or Triton X-100 (Tx)-treated wild-type viruses. Pseudotypes or pseudovirus (PV), characterized by a lentivirus core bearing human influenza NA and avian influenza HA, were investigated as an alternative source of antigen and compared to HA-mismatched and Tx-treated viruses, since represent a safer product to be handled. METHODS: Two independent panels of sera were analyzed by ELLA to evaluate the anti-NA response against N1 (A/California/07/2009 (H1N1pdm)) and N2 (A/Hong Kong/4801/2014 (H3N2)). The NA inhibition (NI) antibody titers measured as either the 50% end point or 50% inhibitory concentration (IC50 ) were compared for every source of antigen. RESULTS: The ELLA assay performed well with all three sources of antigen. NI titers measured using each antigen type correlated well when reported either as end point titers or as the IC50 . CONCLUSIONS: This study suggests that HA-mismatched whole virus, Triton-treated wild-type virus or PV can be used to measure NI antibody titers of human sera, but further comparability/validation assays should be performed to assess statistical differences. The data support the use of PV as an attractive alternative source of antigen and justify further investigation to improve stability of this antigen source.


Assuntos
Antígenos Virais/imunologia , Ensaios Enzimáticos/normas , Vírus da Influenza A/imunologia , Lectinas/química , Neuraminidase/imunologia , Octoxinol/farmacologia , Animais , Anticorpos Antivirais/sangue , Antígenos Virais/genética , Aves/virologia , Ensaios Enzimáticos/métodos , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/efeitos dos fármacos , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza A/efeitos dos fármacos , Vacinas contra Influenza/imunologia , Influenza Aviária/virologia , Influenza Humana/virologia , Lentivirus/genética , Lentivirus/imunologia , Neuraminidase/antagonistas & inibidores , Vírus Reordenados/genética , Vírus Reordenados/imunologia
14.
Environ Health Prev Med ; 24(1): 53, 2019 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-31421676

RESUMO

BACKGROUND: Influenza A viruses pose a significant risk to human health because of their wide host range and ability to reassort into novel viruses that can cause serious disease and pandemics. Since transmission of these viruses between humans and pigs can be associated with occupational and environmental exposures, we investigated the association between occupational exposure to pigs, occurrence of acute respiratory illness (ARI), and influenza A virus infection. METHODS: The study was conducted in Kiambu County, the county with the highest level of intensive small-scale pig farming in Kenya. Up to 3 participants (> 2 years old) per household from pig-keeping and non-pig-keeping households were randomly recruited and followed up in 2013 (Sept-Dec) and 2014 (Apr-Aug). Oropharyngeal (OP) and nasopharyngeal (NP) swabs were collected from participants with ARI at the time of study visit. For the animal study, nasal and oropharyngeal swabs, and serum samples were collected from pigs and poultry present in enrolled households. The human and animal swab samples were tested for viral nucleic acid by RT-PCR and sera by ELISA for antibodies. A Poisson generalized linear mixed-effects model was developed to assess the association between pig exposure and occurrence of ARI. RESULTS: Of 1137 human participants enrolled, 625 (55%) completed follow-up visits including 172 (27.5%) pig workers and 453 (72.5%) non-pig workers. Of 130 human NP/OP swabs tested, four (3.1%) were positive for influenza A virus, one pig worker, and three among non-pig workers. Whereas none of the 4462 swabs collected from pig and poultry tested positive for influenza A virus by RT-PCR, 265 of 4273 (6.2%) of the sera tested positive for virus antibodies by ELISA, including 11.6% (230/1990) of the pigs and 1.5% (35/2,283) of poultry. The cumulative incidence of ARI was 16.9% among pig workers and 26.9% among the non-pig workers. The adjusted risk ratio for the association between being a pig worker and experiencing an episode of ARI was 0.56 (95% CI [0.33, 0.93]), after adjusting for potential confounders. CONCLUSIONS: Our findings demonstrate moderate seropositivity for influenza A virus among pigs, suggesting the circulation of swine influenza virus and a potential for interspecies transmission.


Assuntos
Vírus da Influenza A/fisiologia , Influenza Humana/epidemiologia , Infecções por Orthomyxoviridae/epidemiologia , Zoonoses/epidemiologia , Adolescente , Adulto , Animais , Anticorpos Antivirais/sangue , Criança , Feminino , Humanos , Incidência , Vírus da Influenza A/genética , Vírus da Influenza A/imunologia , Influenza Humana/transmissão , Influenza Humana/virologia , Quênia/epidemiologia , Masculino , Pessoa de Meia-Idade , Infecções por Orthomyxoviridae/transmissão , Faringe/virologia , Aves Domésticas/virologia , RNA Viral/genética , Fatores de Risco , Estudos Soroepidemiológicos , Suínos/virologia , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/transmissão , Adulto Jovem , Zoonoses/transmissão
15.
Nat Commun ; 10(1): 3883, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31462639

RESUMO

Germinal center (GC) B cells at viral replication sites acquire specificity to poorly immunogenic but conserved influenza hemagglutinin (HA) epitopes. Here, high-throughput epitope mapping of local GC B cells is used to identify conserved HA epitope selecting cross-reactive antibodies that mediate heterosubtypic protection. A distinct feature of this epitope is an occlusion in the naive trimeric HA structure that is exposed in the post-fusion HA structure to occur under low pH conditions during viral replication. Importantly, systemic immunization by the post-fusion HA antigen results in GC B cells targeting the occluded epitope, and induces a class of protective antibodies that have cross-group specificity and afford protection independent of virus neutralization activity. Furthermore, this class of broadly protective antibodies develops at late time points and persists. Our results identify a class of cross-protective antibodies that are selected at the viral replication site, and provide insights into vaccine strategies using the occluded epitope.


Assuntos
Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Epitopos/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A/imunologia , Animais , Reações Cruzadas , Mapeamento de Epitopos , Centro Germinativo/citologia , Centro Germinativo/imunologia , Humanos , Imunização , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Replicação Viral
16.
Int J Infect Dis ; 89: 21-26, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31470089

RESUMO

BACKGROUND: We measured seroconversion to influenza viruses and incidence of symptomatic influenza virus infection in a cohort of children in Bangkok, Thailand. METHODS: Children aged ≤6 months were followed for two years for acute respiratory illness (ARI) and had serum specimens taken at 6-month intervals and tested by hemagglutination inhibition (HI) assay. Seroconversion was defined as a >4-fold rise in the HI titers between time points with a titer of >40 in the second specimen. Respiratory swabs were tested by rRT-PCR for influenza. Data were analyzed using generalized linear models. RESULTS: Of 350 children, 266 (76%, 147 were healthy and 119 were high-risk) had ≥2 serum specimens collected before influenza vaccination. During the 2-year follow-up, 266 children contributed 370 person-years of observation, excluding post-vaccination periods. We identified 32 ARI cases with rRT-PCR-confirmed influenza virus infection (7 infections/100 person-years, 95% confidence interval [CI], 4-11). There were 126 episodes of influenza virus infection, resulting in a seroconversion rate of 35 infections/100 person-years (95% CI, 30-42). Rates in healthy and high-risk children did not differ. CONCLUSIONS: Influenza virus infection is common during the first two years of life among Thai children. A large proportion of infections may not be detected using the ARI case definition.


Assuntos
Vírus da Influenza A/imunologia , Influenza Humana/epidemiologia , Vacinação , Pré-Escolar , Estudos de Coortes , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Incidência , Lactente , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Modelos Lineares , Masculino , Soroconversão , Tailândia/epidemiologia
17.
PLoS Pathog ; 15(8): e1007989, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31412088

RESUMO

Defining the most penetrating correlates of protective memory T cells is key for designing improved vaccines and T cell therapies. Here, we evaluate how interleukin (IL-2) production by memory CD4 T cells, a widely held indicator of their protective potential, impacts immune responses against murine influenza A virus (IAV). Unexpectedly, we show that IL-2-deficient memory CD4 T cells are more effective on a per cell basis at combating IAV than wild-type memory cells that produce IL-2. Improved outcomes orchestrated by IL-2-deficient cells include reduced weight loss and improved respiratory function that correlate with reduced levels of a broad array of inflammatory factors in the infected lung. Blocking CD70-CD27 signals to reduce CD4 T cell IL-2 production tempers the inflammation induced by wild-type memory CD4 T cells and improves the outcome of IAV infection in vaccinated mice. Finally, we show that IL-2 administration drives rapid and extremely potent lung inflammation involving NK cells, which can synergize with sublethal IAV infection to promote acute death. These results suggest that IL-2 production is not necessarily an indicator of protective CD4 T cells, and that the lung environment is particularly sensitive to IL-2-induced inflammation during viral infection.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Memória Imunológica/imunologia , Vírus da Influenza A/imunologia , Interleucina-2/metabolismo , Infecções por Orthomyxoviridae/imunologia , Pneumonia/imunologia , Animais , Feminino , Mediadores da Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/metabolismo , Infecções por Orthomyxoviridae/virologia , Pneumonia/metabolismo , Pneumonia/virologia
18.
Nat Microbiol ; 4(11): 1930-1940, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31358982

RESUMO

The early phase of influenza infection occurs in the upper respiratory tract and the trachea, but little is known about the initial events of virus recognition and control of viral dissemination by the immune system. Here, we report that inflammatory dendritic cells (IDCs) are recruited to the trachea shortly after influenza infection through type I interferon-mediated production of the chemokine CCL2. We further show that recruited IDCs express the C-type lectin receptor SIGN-R1, which mediates direct recognition of the virus by interacting with N-linked glycans present in glycoproteins of the virion envelope. Activation of IDCs via SIGN-R1 triggers the production of the chemokines CCL5, CXCL9 and CXCL10, which initiate the recruitment of protective natural killer (NK) cells in the infected trachea. In the absence of SIGN-R1, the recruitment and activation of NK cells is impaired, leading to uncontrolled viral proliferation. In sum, our results provide insight into the orchestration of the early cellular and molecular events involved in immune protection against influenza.


Assuntos
Moléculas de Adesão Celular/metabolismo , Células Dendríticas/imunologia , Vírus da Influenza A/imunologia , Lectinas Tipo C/metabolismo , Infecções por Orthomyxoviridae/imunologia , Receptores de Superfície Celular/metabolismo , Animais , Quimiocinas/metabolismo , Modelos Animais de Doenças , Cães , Interferon Tipo I/metabolismo , Células Matadoras Naturais , Células Madin Darby de Rim Canino , Camundongos , Infecções por Orthomyxoviridae/virologia , Traqueia/imunologia , Traqueia/virologia
19.
Nat Microbiol ; 4(11): 1964-1977, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31358986

RESUMO

Despite the cytopathic nature of influenza A virus (IAV) replication, we recently reported that a subset of lung epithelial club cells is able to intrinsically clear the virus and survive infection. However, the mechanisms that drive cell survival during a normally lytic infection remained unclear. Using a loss-of-function screening approach, we discovered that the DNA mismatch repair (MMR) pathway is essential for club cell survival of IAV infection. Repair of virally induced oxidative damage by the DNA MMR pathway not only allowed cell survival of infection, but also facilitated host gene transcription, including the expression of antiviral and stress response genes. Enhanced viral suppression of the DNA MMR pathway prevented club cell survival and increased the severity of viral disease in vivo. Altogether, these results identify previously unappreciated roles for DNA MMR as a central modulator of cellular fate and a contributor to the innate antiviral response, which together control influenza viral disease severity.


Assuntos
Reparo de Erro de Pareamento de DNA , Redes Reguladoras de Genes , Imunidade Inata , Vírus da Influenza A/patogenicidade , Influenza Humana/genética , Células A549 , Animais , Linhagem Celular , Modelos Animais de Doenças , Cães , Regulação da Expressão Gênica , Humanos , Vírus da Influenza A/imunologia , Influenza Humana/imunologia , Células Madin Darby de Rim Canino , Camundongos , Estresse Oxidativo , Replicação Viral
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