Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 64
Filtrar
1.
Nature ; 612(7940): 540-545, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36323336

RESUMO

The BA.2 sublineage of the SARS-CoV-2 Omicron variant has become dominant in most countries around the world; however, the prevalence of BA.4 and BA.5 is increasing rapidly in several regions. BA.2 is less pathogenic in animal models than previously circulating variants of concern1-4. Compared with BA.2, however, BA.4 and BA.5 possess additional substitutions in the spike protein, which play a key role in viral entry, raising concerns that the replication capacity and pathogenicity of BA.4 and BA.5 are higher than those of BA.2. Here we have evaluated the replicative ability and pathogenicity of BA.4 and BA.5 isolates in wild-type Syrian hamsters, human ACE2 (hACE2) transgenic hamsters and hACE2 transgenic mice. We have observed no obvious differences among BA.2, BA.4 and BA.5 isolates in growth ability or pathogenicity in rodent models, and less pathogenicity compared to a previously circulating Delta (B.1.617.2 lineage) isolate. In addition, in vivo competition experiments revealed that BA.5 outcompeted BA.2 in hamsters, whereas BA.4 and BA.2 exhibited similar fitness. These findings suggest that BA.4 and BA.5 clinical isolates have similar pathogenicity to BA.2 in rodents and that BA.5 possesses viral fitness superior to that of BA.2.


Assuntos
COVID-19 , Aptidão Genética , Roedores , SARS-CoV-2 , Animais , Cricetinae , Humanos , Camundongos , COVID-19/virologia , Mesocricetus/virologia , Camundongos Transgênicos , Roedores/virologia , SARS-CoV-2/classificação , SARS-CoV-2/genética , SARS-CoV-2/patogenicidade , SARS-CoV-2/fisiologia , Animais Geneticamente Modificados , Aptidão Genética/genética , Aptidão Genética/fisiologia , Virulência
2.
Nature ; 607(7917): 119-127, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35576972

RESUMO

The recent emergence of SARS-CoV-2 Omicron (B.1.1.529 lineage) variants possessing numerous mutations has raised concerns of decreased effectiveness of current vaccines, therapeutic monoclonal antibodies and antiviral drugs for COVID-19 against these variants1,2. The original Omicron lineage, BA.1, prevailed in many countries, but more recently, BA.2 has become dominant in at least 68 countries3. Here we evaluated the replicative ability and pathogenicity of authentic infectious BA.2 isolates in immunocompetent and human ACE2-expressing mice and hamsters. In contrast to recent data with chimeric, recombinant SARS-CoV-2 strains expressing the spike proteins of BA.1 and BA.2 on an ancestral WK-521 backbone4, we observed similar infectivity and pathogenicity in mice and hamsters for BA.2 and BA.1, and less pathogenicity compared with early SARS-CoV-2 strains. We also observed a marked and significant reduction in the neutralizing activity of plasma from individuals who had recovered from COVID-19 and vaccine recipients against BA.2 compared to ancestral and Delta variant strains. In addition, we found that some therapeutic monoclonal antibodies (REGN10987 plus REGN10933, COV2-2196 plus COV2-2130, and S309) and antiviral drugs (molnupiravir, nirmatrelvir and S-217622) can restrict viral infection in the respiratory organs of BA.2-infected hamsters. These findings suggest that the replication and pathogenicity of BA.2 is similar to that of BA.1 in rodents and that several therapeutic monoclonal antibodies and antiviral compounds are effective against Omicron BA.2 variants.


Assuntos
Antivirais , Tratamento Farmacológico da COVID-19 , SARS-CoV-2 , Animais , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados , Anticorpos Neutralizantes/farmacologia , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/farmacologia , Anticorpos Antivirais/uso terapêutico , Antivirais/farmacologia , Antivirais/uso terapêutico , COVID-19/genética , COVID-19/imunologia , COVID-19/virologia , Cricetinae , Citidina/análogos & derivados , Combinação de Medicamentos , Hidroxilaminas , Indazóis , Lactamas , Leucina , Camundongos , Nitrilas , Prolina , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/genética , SARS-CoV-2/patogenicidade , Glicoproteína da Espícula de Coronavírus/genética , Triazinas , Triazóis
3.
Nature ; 603(7902): 687-692, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35062015

RESUMO

The recent emergence of B.1.1.529, the Omicron variant1,2, has raised concerns of escape from protection by vaccines and therapeutic antibodies. A key test for potential countermeasures against B.1.1.529 is their activity in preclinical rodent models of respiratory tract disease. Here, using the collaborative network of the SARS-CoV-2 Assessment of Viral Evolution (SAVE) programme of the National Institute of Allergy and Infectious Diseases (NIAID), we evaluated the ability of several B.1.1.529 isolates to cause infection and disease in immunocompetent and human ACE2 (hACE2)-expressing mice and hamsters. Despite modelling data indicating that B.1.1.529 spike can bind more avidly to mouse ACE2 (refs. 3,4), we observed less infection by B.1.1.529 in 129, C57BL/6, BALB/c and K18-hACE2 transgenic mice than by previous SARS-CoV-2 variants, with limited weight loss and lower viral burden in the upper and lower respiratory tracts. In wild-type and hACE2 transgenic hamsters, lung infection, clinical disease and pathology with B.1.1.529 were also milder than with historical isolates or other SARS-CoV-2 variants of concern. Overall, experiments from the SAVE/NIAID network with several B.1.1.529 isolates demonstrate attenuated lung disease in rodents, which parallels preliminary human clinical data.


Assuntos
COVID-19/patologia , COVID-19/virologia , Modelos Animais de Doenças , SARS-CoV-2/patogenicidade , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Cricetinae , Feminino , Humanos , Pulmão/patologia , Pulmão/virologia , Masculino , Mesocricetus , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Carga Viral
4.
Cancer Sci ; 114(4): 1256-1269, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36529525

RESUMO

We previously reported that regulatory T (Treg) cells expressing CTLA-4 on the cell surface are abundant in head and neck squamous cell carcinoma (HNSCC). The role of expanded Treg cells in the tumor microenvironment of HNSCC remains unclear. In this study, we reveal that the tumor microenvironment of HNSCC is characterized by the high expression of genes related to Treg cells, dendritic cells (DCs), and interleukin (IL)-17-related molecules. Increased expression of IL17A, IL17F, or IL23A contributes to a favorable prognosis of HNSCC. In the tumor microenvironment of HNSCC, IL23A and IL12B are expressed in mature dendritic cells enriched in regulatory molecules (mregDCs). The mregDCs in HNSCC are a migratory and mature phenotype; their signature genes strongly correlate with Treg signature genes in HNSCC. We also observed that IL17A was highly expressed in Th17 cells and exhausted CD8+ T cells in HNSCC. These data suggest that mregDCs in HNSCC may contribute to the prognosis by balancing Treg cells and effector T cells that produce IL-17. Targeting mregDCs may be a novel strategy for developing new immune therapies against HNSCC.


Assuntos
Neoplasias de Cabeça e Pescoço , Linfócitos T Reguladores , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Linfócitos T CD8-Positivos , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/metabolismo , Prognóstico , Células Dendríticas , Microambiente Tumoral
5.
PLoS Pathog ; 17(12): e1010085, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34882757

RESUMO

Regulatory T (Treg) cells, which constitute about 5-10% of CD4+T cells expressing Foxp3 transcription factor and CD25(IL-2 receptor α chain), are key regulators in controlling immunological self-tolerance and various immune responses. However, how Treg cells control antigen-specific immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unclear. In this study, we examined the effect of transient breakdown of the immunological tolerance induced by Treg-cell depletion on adaptive immune responses against administered SARS-CoV-2 antigen, spike protein 1 (S1). Notably, without the use of adjuvants, transient Treg-cell depletion in mice induced anti-S1 antibodies that neutralized authentic SARS-CoV-2, follicular helper T cell formation and S1-binding germinal center B cell responses, but prevented the onset of developing autoimmune diseases. To further clarify the mechanisms, we investigated maturation of dendritic cells (DCs), which is essential to initiate antigen-specific immunity. We found that the transient Treg-cell depletion resulted in maturation of both migratory and resident DCs in draining lymph nodes that captured S1-antigen. Moreover, we observed S1-specific CD4+ T cells and CD8+ T cells with interferon-γ production. Thus, captured S1 was successfully presented by DCs, including cross-presentation to CD8+ T cells. These data indicate that transient Treg-cell depletion in the absence of adjuvants induces maturation of antigen-presenting DCs and succeeds in generating antigen-specific humoral and cellular immunity against emerging SARS-CoV-2 antigens. Finally, we showed that SARS-CoV-2 antigen-specific immune responses induced by transient Treg-cell depletion in the absence of adjuvants were compatible with those induced with an effective adjuvant, polyriboinosinic:polyribocytidyl acid (poly IC) and that the combination of transient Treg-cell depletion with poly IC induced potent responses. These findings highlight the capacity for manipulating Treg cells to induce protective adaptive immunity to SARS-CoV-2 with activating antigen-presenting DCs, which may improve the efficacy of ongoing vaccine therapies and help enhance responses to emerging SARS-CoV-2 variants.


Assuntos
Imunidade Adaptativa/imunologia , Antígenos Virais/imunologia , COVID-19/imunologia , Fatores de Transcrição Forkhead/imunologia , SARS-CoV-2/imunologia , Animais , Apresentação de Antígeno/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , COVID-19/virologia , Chlorocebus aethiops , Células Dendríticas/imunologia , Feminino , Centro Germinativo/imunologia , Humanos , Tolerância Imunológica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos MRL lpr , Linfócitos T Reguladores/imunologia , Células Vero
6.
Virol J ; 20(1): 146, 2023 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-37443091

RESUMO

BACKGROUND: The mucosa serves as the first defence against pathogens and facilitates the surveillance and elimination of symbiotic bacteria by mucosal immunity. Recently, the mRNA vaccine against SARS-CoV-2 has been demonstrated to induce secretory antibodies in the oral and nasal cavities in addition to a systemic immune response. However, the mechanism of induced immune stimulation effect on mucosal immunity and commensal bacteria profile remains unclear. METHODS: Here, we longitudinally analysed the changing nasal microbiota and both systemic and nasal immune response upon SARS-CoV-2 mRNA vaccination, and evaluated how mRNA vaccination influenced nasal microbiota in 18 healthy participants who had received the third BNT162b. RESULTS: The nasal S-RBD IgG level correlated significantly with plasma IgG levels until 1 month and the levels were sustained for 3 months post-vaccination. In contrast, nasal S-RBD IgA induction peaked at 1 month, albeit slightly, and correlated only with plasma IgA, but the induction level decreased markedly at 3 months post-vaccination. 16 S rRNA sequencing of the nasal microbiota post-vaccination revealed not an overall change, but a decrease in certain opportunistic bacteria, mainly Fusobacterium. The decrease in these bacteria was more pronounced in those who exhibited nasal S-RBD IgA induction, and those with higher S-RBD IgA induction had lower relative amounts of potentially pathogenic bacteria such as Pseudomonas pre-vaccination. In addition, plasma and mucosal S-RBD IgG levels correlated with decreased commensal pathogens such as Finegoldia. CONCLUSIONS: These findings suggest that the third dose of SARS-CoV-2 mRNA vaccination induced S-RBD antibodies in the nasal mucosa and may have stimulated mucosal immunity against opportunistic bacterial pathogens. This effect, albeit probably secondary, may be considered one of the benefits of mRNA vaccination. Furthermore, our data suggest that a cooperative function of mucosal and systemic immunity in the reduction of bacteria and provides a better understanding of the symbiotic relationship between the host and bacteria in the nasal mucosa.


Assuntos
COVID-19 , Cavidade Nasal , Humanos , SARS-CoV-2 , Vacinas contra COVID-19 , COVID-19/prevenção & controle , Mucosa Nasal , Vacinação , Imunidade nas Mucosas , RNA Mensageiro , Imunoglobulina A , Imunoglobulina G , Anticorpos Antivirais , Anticorpos Neutralizantes
7.
Proc Natl Acad Sci U S A ; 117(34): 20696-20705, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32769209

RESUMO

Regulatory T (Treg) cells, expressing CD25 (interleukin-2 receptor α chain) and Foxp3 transcription factor, maintain immunological self-tolerance and suppress various immune responses. Here we report a feature of skin Treg cells expanded by ultraviolet B (UVB) exposure. We found that skin Treg cells possessing a healing function are expanded by UVB exposure with the expression of an endogenous opioid precursor, proenkephalin (PENK). Upon UVB exposure, skin Treg cells were expanded with a unique TCR repertoire. Also, they highly expressed a distinctive set of genes enriched in "wound healing involved in inflammatory responses" and the "neuropeptide signaling pathway," as indicated by the high expression of Penk. We found that not only was PENK expression at the protein level detected in the UVB-expanded skin Treg (UVB-skin Treg) cells, but that a PENK-derived neuropeptide, methionine enkephalin (Met-ENK), from Treg cells promoted the outgrowth of epidermal keratinocytes in an ex vivo skin explant assay. Notably, UVB-skin Treg cells also promoted wound healing in an in vivo wound closure assay. In addition, UVB-skin Treg cells produced amphiregulin (AREG), which plays a key role in Treg-mediated tissue repair. Identification of a unique function of PENK+ UVB-skin Treg cells provides a mechanism for maintaining skin homeostasis.


Assuntos
Encefalinas/metabolismo , Precursores de Proteínas/metabolismo , Linfócitos T Reguladores/metabolismo , Cicatrização/fisiologia , Anfirregulina/metabolismo , Animais , Células Cultivadas , Encefalina Metionina/metabolismo , Encefalinas/efeitos da radiação , Feminino , Homeostase/fisiologia , Humanos , Tolerância Imunológica/imunologia , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Precursores de Proteínas/efeitos da radiação , Tolerância a Antígenos Próprios/imunologia , Pele/metabolismo , Raios Ultravioleta , Cicatrização/imunologia
12.
J Virol ; 93(13)2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30971475

RESUMO

Saliva from the mosquito vector of flaviviruses is capable of changing the local immune environment, leading to an increase in flavivirus-susceptible cells at the infected bite site. In addition, an antibody response to specific salivary gland (SG) components changes the pathogenesis of flaviviruses in human populations. To investigate whether antigenic SG proteins are capable of enhancing infection with Zika virus (ZIKV), a reemerging flavivirus primarily transmitted by the Aedes aegypti mosquito, we screened for antigenic SG proteins using a yeast display library and demonstrate that a previously undescribed SG protein we term neutrophil stimulating factor 1 (NeSt1) activates primary mouse neutrophils ex vivo Passive immunization against NeSt1 decreases pro-interleukin-1ß and CXCL2 expression, prevents macrophages from infiltrating the bite site, protects susceptible IFNAR-/- IFNGR-/- (AG129) mice from early ZIKV replication, and ameliorates virus-induced pathogenesis. These findings indicate that NeSt1 stimulates neutrophils at the mosquito bite site to change the immune microenvironment, allowing a higher level of early viral replication and enhancing ZIKV pathogenesis.IMPORTANCE When a Zika virus-infected mosquito bites a person, mosquito saliva is injected into the skin along with the virus. Molecules in this saliva can make virus infection more severe by changing the immune system to make the skin a better place for the virus to replicate. We identified a molecule that activates immune cells, called neutrophils, to recruit other immune cells, called macrophages, that the virus can infect. We named this molecule neutrophil-stimulating factor 1 (NeSt1). When we used antibodies to block NeSt1 in mice and then allowed Zika virus-infected mosquitoes to feed on these mice, they survived much better than mice that do not have antibodies against NeSt1. These findings give us more information about how mosquito saliva enhances virus infection, and it is possible that a vaccine against NeSt1 might protect people against severe Zika virus infection.


Assuntos
Aedes/virologia , Neutrófilos/metabolismo , Neutrófilos/virologia , Infecção por Zika virus/imunologia , Zika virus/imunologia , Aedes/imunologia , Animais , Arbovírus , Quimiocina CCL2 , Quimiocina CXCL2/metabolismo , Modelos Animais de Doenças , Feminino , Imunidade , Interleucina-1/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mosquitos Vetores/virologia , Precursores de Proteínas/metabolismo , Células RAW 264.7 , Saliva/virologia , Glândulas Salivares/virologia , Replicação Viral , Zika virus/patogenicidade , Infecção por Zika virus/virologia
14.
Nature ; 501(7468): 551-5, 2013 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-23842494

RESUMO

Avian influenza A viruses rarely infect humans; however, when human infection and subsequent human-to-human transmission occurs, worldwide outbreaks (pandemics) can result. The recent sporadic infections of humans in China with a previously unrecognized avian influenza A virus of the H7N9 subtype (A(H7N9)) have caused concern owing to the appreciable case fatality rate associated with these infections (more than 25%), potential instances of human-to-human transmission, and the lack of pre-existing immunity among humans to viruses of this subtype. Here we characterize two early human A(H7N9) isolates, A/Anhui/1/2013 (H7N9) and A/Shanghai/1/2013 (H7N9); hereafter referred to as Anhui/1 and Shanghai/1, respectively. In mice, Anhui/1 and Shanghai/1 were more pathogenic than a control avian H7N9 virus (A/duck/Gunma/466/2011 (H7N9); Dk/GM466) and a representative pandemic 2009 H1N1 virus (A/California/4/2009 (H1N1pdm09); CA04). Anhui/1, Shanghai/1 and Dk/GM466 replicated well in the nasal turbinates of ferrets. In nonhuman primates, Anhui/1 and Dk/GM466 replicated efficiently in the upper and lower respiratory tracts, whereas the replicative ability of conventional human influenza viruses is typically restricted to the upper respiratory tract of infected primates. By contrast, Anhui/1 did not replicate well in miniature pigs after intranasal inoculation. Critically, Anhui/1 transmitted through respiratory droplets in one of three pairs of ferrets. Glycan arrays showed that Anhui/1, Shanghai/1 and A/Hangzhou/1/2013 (H7N9) (a third human A(H7N9) virus tested in this assay) bind to human virus-type receptors, a property that may be critical for virus transmissibility in ferrets. Anhui/1 was found to be less sensitive in mice to neuraminidase inhibitors than a pandemic H1N1 2009 virus, although both viruses were equally susceptible to an experimental antiviral polymerase inhibitor. The robust replicative ability in mice, ferrets and nonhuman primates and the limited transmissibility in ferrets of Anhui/1 suggest that A(H7N9) viruses have pandemic potential.


Assuntos
Vírus da Influenza A , Influenza Humana/virologia , Infecções por Orthomyxoviridae/virologia , Replicação Viral , Animais , Antivirais/farmacologia , Células Cultivadas , Galinhas/virologia , RNA Polimerases Dirigidas por DNA/antagonistas & inibidores , Cães , Inibidores Enzimáticos/farmacologia , Feminino , Furões/virologia , Humanos , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H1N1/enzimologia , Vírus da Influenza A/química , Vírus da Influenza A/efeitos dos fármacos , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/patogenicidade , Influenza Humana/tratamento farmacológico , Macaca fascicularis/virologia , Células Madin Darby de Rim Canino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Doenças dos Macacos/patologia , Doenças dos Macacos/virologia , Neuraminidase/antagonistas & inibidores , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/transmissão , Codorniz/virologia , Suínos/virologia , Porco Miniatura/virologia , Replicação Viral/efeitos dos fármacos
16.
J Infect Dis ; 215(11): 1720-1724, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28472297

RESUMO

Zika virus (ZIKV) can be transmitted by mosquito bite or sexual contact. Using mice that lack the type I interferon receptor, we examined sexual transmission of ZIKV. Electron microscopy analyses showed association of virions with developing sperm within testes as well as with mature sperm within epididymis. When ZIKV-infected male mice were mated with naive female mice, the weight of fetuses at embryonic day 18.5 was significantly reduced compared with the control group. Additionally, we found ocular deformities in a minority of the fetuses. These results suggest that ZIKV causes fetal abnormalities after female mating with an infected male.


Assuntos
Retardo do Crescimento Fetal/virologia , Complicações Infecciosas na Gravidez/virologia , Doenças Virais Sexualmente Transmissíveis/transmissão , Infecção por Zika virus/transmissão , Zika virus , Animais , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Gravidez , Doenças Virais Sexualmente Transmissíveis/virologia , Infecção por Zika virus/virologia
17.
J Infect Dis ; 216(5): 582-593, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28931216

RESUMO

Antiviral compounds (eg, the neuraminidase inhibitor oseltamivir) are invaluable for the treatment of individuals infected with influenza A viruses of the H7N9 subtype (A[H7N9]), which have infected and killed hundreds of persons. However, oseltamivir treatment often leads to the emergence of resistant viruses in immunocompromised individuals. To better understand the emergence and properties of oseltamivir-resistant A(H7N9) viruses in immunosuppressed individuals, we infected immunosuppressed cynomolgus macaques with an A(H7N9) virus and treated them with oseltamivir. Disease severity and mortality were higher in immunosuppressed than in immunocompetent animals. Oseltamivir treatment at 2 different doses reduced A(H7N9) viral titers in infected animals, but even high-dose oseltamivir did not block viral replication sufficiently to suppress the emergence of resistant variants. Some resistant variants were not appreciably attenuated in cultured cells, but an oseltamivir-resistant A(H7N9) virus did not transmit among ferrets. These findings are useful for the control of A(H7N9) virus infections in clinical settings.


Assuntos
Farmacorresistência Viral Múltipla , Hospedeiro Imunocomprometido , Subtipo H7N9 do Vírus da Influenza A/efeitos dos fármacos , Macaca fascicularis/virologia , Infecções por Orthomyxoviridae/tratamento farmacológico , Oseltamivir/uso terapêutico , Animais , Antivirais/uso terapêutico , Relação Dose-Resposta a Droga , Feminino , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Masculino , Neuraminidase/antagonistas & inibidores , Neuraminidase/metabolismo , Infecções por Orthomyxoviridae/veterinária , Infecções por Orthomyxoviridae/virologia , Replicação Viral
18.
J Infect Dis ; 212(12): 1939-48, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26123562

RESUMO

BACKGROUND: Secondary bacterial infections after influenza can be a serious problem, especially in young children and the elderly, yet the efficacy of current vaccines is limited. Earlier work demonstrated that a replication-incompetent PB2-knockout (PB2-KO) influenza virus possessing a foreign gene in the coding region of its PB2 segment can serve as a platform for a bivalent vaccine. METHODS: In the current study, we generated the PB2-KO virus expressing pneumococcal surface protein A (PspA), PB2-KO-PspA virus, the replication of which is restricted to PB2-expressing cells. We then examined the protective efficacy of intranasal immunization with this virus as a bivalent vaccine in a mouse model. RESULTS: High levels of influenza virus-specific and PspA-specific antibodies were induced in the serum and airways of immunized mice. The intranasally immunized mice were protected from lethal doses of influenza virus or Streptococcus pneumoniae. These mice were also completely protected from secondary pneumococcal pneumonia after influenza virus infection. CONCLUSIONS: These findings indicate that our recombinant influenza virus serves as a novel and powerful bivalent vaccine against primary and secondary pneumococcal pneumonia as well as influenza.


Assuntos
Coinfecção/prevenção & controle , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Orthomyxoviridae/imunologia , Vacinas Pneumocócicas/imunologia , Pneumonia Pneumocócica/prevenção & controle , Administração Intranasal , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Modelos Animais de Doenças , Técnicas de Inativação de Genes , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/genética , Camundongos , Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/complicações , Vacinas Pneumocócicas/administração & dosagem , Vacinas Pneumocócicas/genética , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Proteínas Virais/genética
19.
J Virol ; 88(6): 3127-34, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24371069

RESUMO

UNLABELLED: Novel avian-origin influenza A(H7N9) viruses were first reported to infect humans in March 2013. To date, 143 human cases, including 45 deaths, have been recorded. By using sequence comparisons and phylogenetic and ancestral inference analyses, we identified several distinct amino acids in the A(H7N9) polymerase PA protein, some of which may be mammalian adapting. Mutant viruses possessing some of these amino acid changes, singly or in combination, were assessed for their polymerase activities and growth kinetics in mammalian and avian cells and for their virulence in mice. We identified several mutants that were slightly more virulent in mice than the wild-type A(H7N9) virus, A/Anhui/1/2013. These mutants also exhibited increased polymerase activity in human cells but not in avian cells. Our findings indicate that the PA protein of A(H7N9) viruses has several amino acid substitutions that are attenuating in mammals. IMPORTANCE: Novel avian-origin influenza A(H7N9) viruses emerged in the spring of 2013. By using computational analyses of A(H7N9) viral sequences, we identified several amino acid changes in the polymerase PA protein, which we then assessed for their effects on viral replication in cultured cells and mice. We found that the PA proteins of A(H7N9) viruses possess several amino acid substitutions that cause attenuation in mammals.


Assuntos
Substituição de Aminoácidos , Subtipo H7N9 do Vírus da Influenza A/enzimologia , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Influenza Humana/virologia , Doenças das Aves Domésticas/virologia , RNA Polimerase Dependente de RNA/genética , Proteínas Virais/genética , Animais , Galinhas , Patos , Feminino , Humanos , Subtipo H7N9 do Vírus da Influenza A/classificação , Subtipo H7N9 do Vírus da Influenza A/genética , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Vírus da Influenza A/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Filogenia , RNA Polimerase Dependente de RNA/metabolismo , Proteínas Virais/metabolismo , Virulência
20.
J Virol ; 88(16): 8981-97, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24899188

RESUMO

UNLABELLED: Occasional transmission of highly pathogenic avian H5N1 influenza viruses to humans causes severe pneumonia with high mortality. To better understand the mechanisms via which H5N1 viruses induce severe disease in humans, we infected cynomolgus macaques with six different H5N1 strains isolated from human patients and compared their pathogenicity and the global host responses to the virus infection. Although all H5N1 viruses replicated in the respiratory tract, there was substantial heterogeneity in their replicative ability and in the disease severity induced, which ranged from asymptomatic to fatal. A comparison of global gene expression between severe and mild disease cases indicated that interferon-induced upregulation of genes related to innate immunity, apoptosis, and antigen processing/presentation in the early phase of infection was limited in severe disease cases, although interferon expression was upregulated in both severe and mild cases. Furthermore, coexpression analysis of microarray data, which reveals the dynamics of host responses during the infection, demonstrated that the limited expression of these genes early in infection led to a failure to suppress virus replication and to the hyperinduction of genes related to immunity, inflammation, coagulation, and homeostasis in the late phase of infection, resulting in a more severe disease. Our data suggest that the attenuated interferon-induced activation of innate immunity, apoptosis, and antigen presentation in the early phase of H5N1 virus infection leads to subsequent severe disease outcome. IMPORTANCE: Highly pathogenic avian H5N1 influenza viruses sometimes transmit to humans and cause severe pneumonia with ca. 60% lethality. The continued circulation of these viruses poses a pandemic threat; however, their pathogenesis in mammals is not fully understood. We, therefore, investigated the pathogenicity of six H5N1 viruses and compared the host responses of cynomolgus macaques to the virus infection. We identified differences in the viral replicative ability of and in disease severity caused by these H5N1 viruses. A comparison of global host responses between severe and mild disease cases identified the limited upregulation of interferon-stimulated genes early in infection in severe cases. The dynamics of the host responses indicated that the limited response early in infection failed to suppress virus replication and led to hyperinduction of pathological condition-related genes late in infection. These findings provide insight into the pathogenesis of H5N1 viruses in mammals.


Assuntos
Regulação Viral da Expressão Gênica/genética , Expressão Gênica/genética , Virus da Influenza A Subtipo H5N1/genética , Infecções por Orthomyxoviridae/virologia , Primatas/virologia , Animais , Apresentação de Antígeno/imunologia , Apoptose/imunologia , Células Cultivadas , Cães , Expressão Gênica/imunologia , Regulação Viral da Expressão Gênica/imunologia , Humanos , Imunidade Inata/imunologia , Inflamação/imunologia , Inflamação/virologia , Virus da Influenza A Subtipo H5N1/imunologia , Macaca/imunologia , Macaca/virologia , Macaca fascicularis/imunologia , Macaca fascicularis/virologia , Células Madin Darby de Rim Canino , Infecções por Orthomyxoviridae/imunologia , Primatas/imunologia , Sistema Respiratório/imunologia , Sistema Respiratório/virologia , Índice de Gravidade de Doença , Replicação Viral/genética , Replicação Viral/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA