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1.
Clin Infect Dis ; 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300819

RESUMO

BACKGROUND: Influenza causes a substantial burden worldwide, and current seasonal influenza vaccine has suboptimal effectiveness. To develop better, more broadly protective vaccines, a more thorough understanding is needed of how antibodies that target the influenza virus surface antigens, hemagglutinin (HA; including head and stalk regions), and neuraminidase (NA), impact influenza illness and virus transmission. METHODS: We used a case-ascertained, community-based study of household influenza virus transmission set in Managua, Nicaragua. Using data from 170 RT-PCR-confirmed influenza virus A(H1N1)pdm infections and 45 household members with serologically-confirmed infection, we examined the association of pre-existing NA, hemagglutination inhibiting (HAI), and HA stalk antibody levels and influenza viral shedding and disease duration using accelerated failure time (AFT) models. RESULTS: Among RT-PCR-confirmed infections in adults, pre-existing anti-NA antibody levels of ≥40 were associated with a 69% (95%CI: 34%, 85%) shortened shedding duration (mean: 1.0 vs 3.2 days). NA antibody levels of ≥80 were associated with further shortened shedding and significantly shortened symptom duration (ILI: 82%, 95%CI: 39%, 95%). Among RT-PCR-confirmed infections in children, HAI titers of ≥1:20 were associated with a 32% (95%CI: 13%, 47%) shortened shedding duration (mean: 3.9 vs 6.0 days). CONCLUSIONS: Our results suggest that anti-NA antibodies play a large role in reducing influenza illness duration in adults and may impact transmission, most clearly among adults. Neuraminidase should be considered as an additional target in next-generation influenza virus vaccine development.

2.
Nat Med ; 25(6): 962-967, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31160818

RESUMO

Influenza viruses remain a severe threat to human health, causing up to 650,000 deaths annually1,2. Seasonal influenza virus vaccines can prevent infection, but are rendered ineffective by antigenic drift. To provide improved protection from infection, novel influenza virus vaccines that target the conserved epitopes of influenza viruses, specifically those in the hemagglutinin stalk and neuraminidase, are currently being developed3. Antibodies against the hemagglutinin stalk confer protection in animal studies4-6. However, no data exist on natural infections in humans, and these antibodies do not show activity in the hemagglutination inhibition assay, the hemagglutination inhibition titer being the current correlate of protection against influenza virus infection7-9. While previous studies have investigated the protective effect of cellular immune responses and neuraminidase-inhibiting antibodies, additional serological correlates of protection from infection could aid the development of broadly protective or universal influenza virus vaccines10-13. To address this gap, we performed a household transmission study to identify alternative correlates of protection from infection and disease in naturally exposed individuals. Using this study, we determined 50% protective titers and levels for hemagglutination inhibition, full-length hemagglutinin, neuraminidase and hemagglutinin stalk-specific antibodies. Further, we found that hemagglutinin stalk antibodies independently correlated with protection from influenza virus infection.


Assuntos
Vírus da Influenza A Subtipo H1N1/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Adolescente , Adulto , Idoso , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Lactente , Recém-Nascido , Influenza Humana/epidemiologia , Masculino , Pessoa de Meia-Idade , Nicarágua/epidemiologia , Pandemias/prevenção & controle , Adulto Jovem
3.
Emerg Microbes Infect ; 8(1): 155-168, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30866770

RESUMO

Influenza viruses of the H4 subtype are widespread in wild birds, circulate in domestic poultry, readily infect mammals, and tolerate the insertion of a polybasic cleavage site. In addition, serological evidence suggests that humans working with poultry are exposed to these viruses. While H4 viruses are not of immediate pandemic concern, there is a lack of knowledge regarding their antigenicity. In order to study viruses of the H4 subtype, we generated and characterized a panel of antibodies that bind a wide variety of H4 hemagglutinins from avian and swine isolates of both the Eurasian and North American lineage. We further characterized these antibodies using novel recombinant H4N6 viruses that were found to be lethal in DBA/2J mice. Non-neutralizing antibodies, which had activity in an antibody dependent cell-mediated cytotoxicity reporter assay in vitro, protected mice against challenge in vivo, highlighting the importance of effector functions. Our data suggest a high degree of antigenic conservation of the H4 hemagglutinin.


Assuntos
Anticorpos Neutralizantes/administração & dosagem , Aves/virologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Suínos/virologia , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/administração & dosagem , Anticorpos Antivirais/imunologia , Aves/imunologia , Reações Cruzadas , Modelos Animais de Doenças , Feminino , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/patogenicidade , Camundongos , Camundongos Endogâmicos DBA , Infecções por Orthomyxoviridae/imunologia , Suínos/imunologia
4.
J Virol ; 93(6)2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30626682

RESUMO

Protection from influenza virus infection is canonically associated with antibodies that neutralize the virus by blocking the interaction between the viral hemagglutinin and host cell receptors. However, protection can also be conferred by other mechanisms, including antibody-mediated effector functions. Here, we report the characterization of 22 broadly cross-reactive, nonneutralizing antibodies specific for influenza B virus hemagglutinin. The majority of these antibodies recognized influenza B viruses isolated over the period of 73 years and bind the conserved stalk domain of the hemagglutinin. A proportion of the characterized antibodies protected mice from both morbidity and mortality after challenge with a lethal dose of influenza B virus. Activity in an antibody-dependent cell-mediated cytotoxicity reporter assay correlated strongly with protection, suggesting that Fc-dependent effector function determines protective efficacy. The information regarding mechanism of action and epitope location stemming from our characterization of these antibodies will inform the design of urgently needed vaccines that could induce broad protection against influenza B viruses.IMPORTANCE While broadly protective antibodies against the influenza A virus hemagglutinin have been well studied, very limited information is available for antibodies that broadly recognize influenza B viruses. Similarly, the development of a universal or broadly protective influenza B virus vaccine lags behind the development of such a vaccine for influenza A virus. More information about epitope location and mechanism of action of broadly protective influenza B virus antibodies is required to inform vaccine development. In addition, protective antibodies could be a useful tool to treat or prevent influenza B virus infection in pediatric cohorts or in a therapeutic setting in immunocompromised individuals in conjugation with existing treatment avenues.

5.
Emerg Microbes Infect ; 7(1): 110, 2018 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-29925896

RESUMO

Influenza viruses remain a major global public health risk. In addition to seasonal influenza viruses, epizootic influenza A H7 subtype viruses of both the Asian and North American lineage are of concern due to their pandemic potential. In China, the simultaneous occurrence of H7N9 zoonotic episodes and seasonal influenza virus epidemics could potentially lead to novel reassortant viruses with the ability to efficiently spread among humans. Recently, the H7N9 virus has evolved into two new lineages, the Pearl River Delta and the Yangtze River Delta clade. This development has also resulted in viruses with a polybasic cleavage site in the hemagglutinin that are highly pathogenic in avian species and have caused human infections. In addition, an outbreak of a highly pathogenic H7N8 strain was reported in the US state of Indiana in 2016. Furthermore, an H7N2 feline virus strain caused an outbreak in cats in an animal shelter in New York City in 2016, resulting in one human zoonotic event. In this study, mouse monoclonal antibodies previously raised against the hemagglutinin of the A/Shanghai/1/2013 (H7N9) virus were tested for their (cross-) reactivity to these novel H7 viruses. Moreover, the functionality of these antibodies was assessed in vitro in hemagglutination inhibition and microneutralization assays. The therapeutic and prophylactic efficacy of the broadly reactive antibodies against novel H7 viruses was determined in vivo in mouse passive transfer-viral challenge experiments. Our results provide data about the conservation of critical H7 epitopes and could inform the selection of pre-pandemic H7 vaccine strains.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Reações Cruzadas/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Subtipo H7N9 do Vírus da Influenza A/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Animais , Anticorpos Neutralizantes/imunologia , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Subtipo H7N9 do Vírus da Influenza A/classificação , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Testes de Neutralização , Infecções por Orthomyxoviridae/mortalidade , Infecções por Orthomyxoviridae/prevenção & controle , Filogenia , Ligação Proteica/imunologia , Conformação Proteica
6.
mSphere ; 3(3)2018 May-Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29720525

RESUMO

Arenaviruses pose a major public health threat and cause numerous infections in humans each year. Although most viruses belonging to this family do not cause disease in humans, some arenaviruses, such as Lassa virus and Machupo virus, are the etiological agents of lethal hemorrhagic fevers. The absence of a currently licensed vaccine and the highly pathogenic nature of these viruses both make the necessity of developing viable vaccines and therapeutics all the more urgent. Arenaviruses have a single glycoprotein on the surface of virions, the glycoprotein complex (GPC), and this protein can be used as a target for vaccine development. Here, we describe immunization strategies to generate monoclonal antibodies (MAbs) that cross-react between the glycoprotein complexes of both Old World and New World arenaviruses. Several monoclonal antibodies isolated from immunized mice were highly cross-reactive, binding a range of Old World arenavirus glycoproteins, including that of Lassa virus. One such monoclonal antibody, KL-AV-2A1, bound to GPCs of both New World and Old World viruses, including Lassa and Machupo viruses. These cross-reactive antibodies bound to epitopes present on the glycoprotein 2 subunit of the glycoprotein complex, which is relatively conserved among arenaviruses. Monoclonal antibodies binding to these epitopes, however, did not inhibit viral entry as they failed to neutralize a replication-competent vesicular stomatitis virus pseudotyped with the Lassa virus glycoprotein complex in vitro In addition, no protection from virus challenge was observed in in vivo mouse models. Even so, these monoclonal antibodies might still prove to be useful in the development of clinical and diagnostic assays.IMPORTANCE Several viruses in the Arenaviridae family infect humans and cause severe hemorrhagic fevers which lead to high case fatality rates. Due to their pathogenicity and geographic tropisms, these viruses remain very understudied. As a result, an effective vaccine or therapy is urgently needed. Here, we describe efforts to produce cross-reactive monoclonal antibodies that bind to both New and Old World arenaviruses. All of our MAbs seem to be nonneutralizing and nonprotective and target subunit 2 of the glycoprotein. Due to the lack of reagents such as recombinant glycoproteins and antibodies for rapid detection assays, our MAbs could be beneficial as analytic and diagnostic tools.


Assuntos
Anticorpos Antivirais/imunologia , Arenavirus do Novo Mundo/imunologia , Arenavirus do Velho Mundo/imunologia , Reações Cruzadas , Glicoproteínas/imunologia , Proteínas Estruturais Virais/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/isolamento & purificação , Infecções por Arenaviridae/imunologia , Infecções por Arenaviridae/prevenção & controle , Modelos Animais de Doenças , Mapeamento de Epitopos , Epitopos de Linfócito B/imunologia , Camundongos
7.
PLoS One ; 13(4): e0194830, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29617394

RESUMO

The standard method to quantify the hemagglutinin content of influenza virus vaccines is the single radial immunodiffusion assay. This assay primarily relies on polyclonal antibodies against the head domain of the influenza virus hemagglutinin, which is the main target antigen of influenza virus vaccines. Novel influenza virus vaccine candidates that redirect the immune response towards the evolutionary more conserved hemagglutinin stalk, including chimeric hemagglutinin and headless hemagglutinin constructs, are highly dependent on the structural integrity of the protein to present conformational epitopes for neutralizing antibodies. In this study, we describe a novel enzyme-linked immunosorbent assay that allows quantifying the amount of hemagglutinin with correctly folded stalk domains and which could be further developed into a potency assay for stalk-based influenza virus vaccines.


Assuntos
Ensaio de Imunoadsorção Enzimática , Glicoproteínas de Hemaglutininação de Vírus da Influenza/análise , Vacinas contra Influenza/análise , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Epitopos/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Vírus da Influenza A/metabolismo , Vacinas contra Influenza/genética , Vacinas contra Influenza/imunologia , Vacinas contra Influenza/metabolismo , Domínios Proteicos , Dobramento de Proteína , Proteínas Recombinantes de Fusão/análise , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/química
8.
PLoS One ; 13(4): e0193680, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29641537

RESUMO

Annual immunization against influenza virus is a large international public health effort. Accumulating evidence suggests that antibody mediated cross-reactive immunity against influenza hemagglutinin (HA) strongly correlates with long-lasting cross-protection against influenza virus strains that differ from the primary infection or vaccination strain. However, the optimal strategies for achieving highly cross-reactive antibodies to the influenza virus HA have not yet to be defined. In the current study, using Luminex-based mPlex-Flu assay, developed by our laboratory, to quantitatively measure influenza specific IgG antibody mediated cross-reactivity, we found that prime-boost-boost vaccination of ferrets with rHA proteins admixed with adjuvant elicited higher magnitude and broader cross-reactive antibody responses than that induced by actual influenza viral infection, and this cross-reactive response likely correlated with increased anti-stalk reactive antibodies. We observed a similar phenomenon in mice receiving three sequential vaccinations with rHA proteins from either A/California/07/2009 (H1N1) or A/Hong Kong/1/1968 (H3N2) viruses admixed with Addavax, an MF59-like adjuvant. Using this same mouse vaccination model, we determined that Addavax plays a more significant role in the initial priming event than in subsequent boosts. We also characterized the generation of cross-reactive antibody secreting cells (ASCs) and memory B cells (MBCs) when comparing vaccination to viral infection. We have also found that adjuvant plays a critical role in the generation of long-lived ASCs and MBCs cross-reactive to influenza viruses as a result of vaccination with rHA of influenza virus, and the observed increase in stalk-reactive antibodies likely contributes to this IgG mediated broad cross-reactivity.


Assuntos
Anticorpos Antivirais/imunologia , Hemaglutininas/imunologia , Imunoglobulina G/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza , Vacinação , Animais , Reações Cruzadas , Furões , Camundongos
9.
mSphere ; 2(6)2017 Nov-Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29242836

RESUMO

Human influenza virus infections with avian subtype H7N9 viruses are a major public health concern and have encouraged the development of effective H7 prepandemic vaccines. In this study, baseline and postvaccination serum samples of individuals aged 18 years and older who received a recombinant H7 hemagglutinin vaccine with and without an oil-in-water emulsion (SE) adjuvant were analyzed using a panel of serological assays. While only a small proportion of individuals seroconverted to H7N9 as measured by the conventional hemagglutination inhibition assay, our data show strong induction of anti-H7 hemagglutinin antibodies as measured by an enzyme-linked immunosorbent assay (ELISA). In addition, cross-reactive antibodies against phylogenetically distant group 2 hemagglutinins were induced, presumably targeting the conserved stalk domain of the hemagglutinin. Further analysis confirmed an induction of stalk-specific antibodies, suggesting that epitopes outside the classical antigenic sites are targeted by this vaccine in the context of preexisting immunity to related H3 hemagglutinin. Antibodies induced by H7 vaccination also showed functional activity in antibody-dependent cell-mediated cytotoxicity reporter assays and microneutralization assays. Additionally, our data show that sera from hemagglutination inhibition seroconverters conferred protection in a passive serum transfer experiment against lethal H7N9 virus challenge in mice. Interestingly, sera from hemagglutination inhibition nonseroconverters also conferred partial protection in the lethal animal challenge model. In conclusion, while recombinant H7 vaccination fails to induce measurable levels of hemagglutination-inhibiting antibodies in most subjects, this vaccination regime induces homosubtypic and heterosubtypic cross-reactive binding antibodies that are functional and partly protective in a murine passive transfer challenge model. IMPORTANCE Zoonotic infections with high case fatality rates caused by avian H7N9 influenza viruses have been reported since early 2013 in China. Since then, the fifth wave of the H7N9 epidemic emerged in China, resulting in higher numbers of laboratory-confirmed cases than in previous years. Recently, H7N9 has started to antigenically drift and split into two new lineages, the Pearl River Delta and Yangtze River Delta clades, which do not match stockpiled H7 vaccines well. Humans are immunologically naive to these subtypes, and an H7N9 strain that acquires the capability of efficient human-to-human transmission poses a credible pandemic threat. Other characteristics of H7N9 are raising concerns as well, like its ability to bind to receptors in the human upper respiratory tract, the recent emergence of highly pathogenic variants, and the ability to quickly gain resistance to neuraminidase inhibitors. Therefore, developing and testing H7N9 vaccines constitutes a priority for pandemic preparedness.

10.
Nat Microbiol ; 2(10): 1415-1424, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28827718

RESUMO

A substantial proportion of influenza-related childhood deaths are due to infection with influenza B viruses, which co-circulate in the human population as two antigenically distinct lineages defined by the immunodominant receptor binding protein, haemagglutinin. While broadly cross-reactive, protective monoclonal antibodies against the haemagglutinin of influenza B viruses have been described, none targeting the neuraminidase, the second most abundant viral glycoprotein, have been reported. Here, we analyse a panel of five murine anti-neuraminidase monoclonal antibodies that demonstrate broad binding, neuraminidase inhibition, in vitro antibody-dependent cell-mediated cytotoxicity and in vivo protection against influenza B viruses belonging to both haemagglutinin lineages and spanning over 70 years of antigenic drift. Electron microscopic analysis of two neuraminidase-antibody complexes shows that the conserved neuraminidase epitopes are located on the head of the molecule and that they are distinct from the enzymatic active site. In the mouse model, one therapeutic dose of antibody 1F2 was more protective than the current standard of treatment, oseltamivir, given twice daily for six days.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Epitopos , Vírus da Influenza B/imunologia , Neuraminidase , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/farmacologia , Anticorpos Antivirais/uso terapêutico , Reações Cruzadas , Modelos Animais de Doenças , Cães , Feminino , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza B/efeitos dos fármacos , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Neuraminidase/análise , Infecções por Orthomyxoviridae/tratamento farmacológico , Células Sf9 , Proteínas Virais/imunologia
11.
J Virol ; 91(16)2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28592526

RESUMO

Out of an estimated 31,100 cases since their discovery in 1976, ebolaviruses have caused approximately 13,000 deaths. The vast majority (∼11,000) of these occurred during the 2013-2016 West African epidemic. Three out of five species in the genus are known to cause Ebola Virus Disease in humans. Several monoclonal antibodies against the ebolavirus glycoprotein are currently in development as therapeutics. However, there is still a paucity of monoclonal antibodies that can cross-react between the glycoproteins of different ebolavirus species, and the mechanism of these monoclonal antibody therapeutics is still not understood in detail. Here, we generated a panel of eight murine monoclonal antibodies (MAbs) utilizing a prime-boost vaccination regimen with a Zaire ebolavirus glycoprotein expression plasmid followed by infection with a vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein. We tested the binding breadth of the resulting monoclonal antibodies using a set of recombinant surface glycoproteins from Reston, Taï Forest, Bundibugyo, Zaire, Sudan, and Marburg viruses and found two antibodies that showed pan-ebolavirus binding. An in vivo Stat2-/- mouse model was utilized to test the ability of these MAbs to protect from infection with a vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein. Several of our antibodies, including the broadly binding ones, protected mice from mortality despite lacking neutralization capability in vitro, suggesting their protection may be mediated by Fc-FcR interactions. Indeed, three antibodies displayed cellular phagocytosis and/or antibody-dependent cell-mediated cytotoxicity in vitro Our antibodies, specifically the two identified cross-reactive monoclonal antibodies (KL-2E5 and KL-2H7), might add to the understanding of anti-ebolavirus humoral immunity.IMPORTANCE This study describes the generation of a panel of novel anti-ebolavirus glycoprotein monoclonal antibodies, including two antibodies with broad cross-reactivity to all known ebolavirus species. The antibodies were raised using a heterologous DNA-viral vector prime-boost regimen, resulting in a high proportion of cross-reactive antibodies (25%). Similar vaccination regimens have been used successfully to induce broad protection against influenza viruses in humans, and our limited data indicate that this might be a useful strategy for filovirus vaccines as well. Several of our antibodies showed protective efficacy when tested in a novel murine challenge model and may be developed into future therapeutics.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Proteção Cruzada , Ebolavirus/imunologia , Doença pelo Vírus Ebola/prevenção & controle , Fatores Imunológicos/imunologia , Proteínas do Envelope Viral/imunologia , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Antivirais/administração & dosagem , Citotoxicidade Celular Dependente de Anticorpos , Modelos Animais de Doenças , Fatores Imunológicos/administração & dosagem , Camundongos , Resultado do Tratamento
12.
MBio ; 8(2)2017 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-28325769

RESUMO

Antibody responses to influenza virus hemagglutinin provide protection against infection and are well studied. Less is known about the human antibody responses to the second surface glycoprotein, neuraminidase. Here, we assessed human antibody reactivity to a panel of N1, N2, and influenza B virus neuraminidases in different age groups, including children, adults, and the elderly. Using enzyme-linked immunosorbent assays (ELISA), we determined the breadth, magnitude, and isotype distribution of neuraminidase antibody responses to historic, current, and avian strains, as well as to recent isolates to which these individuals have not been exposed. It appears that antibody levels against N1 neuraminidases were lower than those against N2 or B neuraminidases. The anti-neuraminidase antibody levels increased with age and were, in general, highest against strains that circulated during the childhood of the tested individuals, providing evidence for "original antigenic sin." Titers measured by ELISA correlated well with titers measured by the neuraminidase inhibition assays. However, in the case of the 2009 pandemic H1N1 virus, we found evidence of interference from antibodies binding to the conserved stalk domain of the hemagglutinin. In conclusion, we found that antibodies against the neuraminidase differ in magnitude and breadth between subtypes and age groups in the human population. (This study has been registered at ClinicalTrials.gov under registration no. NCT00336453, NCT00539981, and NCT00395174.)IMPORTANCE Anti-neuraminidase antibodies can afford broad protection from influenza virus infection in animal models and humans. However, little is known about the breadth and magnitude of the anti-neuraminidase response in the human population. Here we assessed antibody levels of children, adults, and the elderly against a panel of N1, N2, and type B influenza virus neuraminidases. We demonstrated that antibody levels measured by ELISA correlate well with functional neuraminidase inhibition titers. This is an important finding since ELISA is a simpler method than functional assays and can be implemented in high-throughput settings to analyze large numbers of samples. Furthermore, we showed that low titers of broadly cross-reactive antibodies against neuraminidase are prevalent in humans. By the use of an appropriate vaccination strategy, these titers could potentially be boosted to levels that might provide broad protection from influenza virus infection.


Assuntos
Anticorpos Antivirais/sangue , Neuraminidase/imunologia , Proteínas Virais/imunologia , Adolescente , Adulto , Crianças Adultas , Fatores Etários , Idoso , Pré-Escolar , Ensaio de Imunoadsorção Enzimática , Humanos , Lactente , Pessoa de Meia-Idade , Neuraminidase/análise , Ensaios Clínicos Controlados Aleatórios como Assunto , Adulto Jovem
13.
J Virol ; 91(12)2017 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-28356526

RESUMO

Seasonal influenza virus epidemics represent a significant public health burden. Approximately 25% of all influenza virus infections are caused by type B viruses, and these infections can be severe, especially in children. Current influenza virus vaccines are an effective prophylaxis against infection but are impacted by rapid antigenic drift, which can lead to mismatches between vaccine strains and circulating strains. Here, we describe a broadly protective vaccine candidate based on chimeric hemagglutinins, consisting of globular head domains from exotic influenza A viruses and stalk domains from influenza B viruses. Sequential vaccination with these constructs in mice leads to the induction of broadly reactive antibodies that bind to the conserved stalk domain of influenza B virus hemagglutinin. Vaccinated mice are protected from lethal challenge with diverse influenza B viruses. Results from serum transfer experiments and antibody-dependent cell-mediated cytotoxicity (ADCC) assays indicate that this protection is antibody mediated and based on Fc effector functions. The present data suggest that chimeric hemagglutinin-based vaccination is a viable strategy to broadly protect against influenza B virus infection.IMPORTANCE While current influenza virus vaccines are effective, they are affected by mismatches between vaccine strains and circulating strains. Furthermore, the antiviral drug oseltamivir is less effective for treating influenza B virus infections than for treating influenza A virus infections. A vaccine that induces broad and long-lasting protection against influenza B viruses is therefore urgently needed.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza B/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Citotoxicidade Celular Dependente de Anticorpos , Modelos Animais de Doenças , Glicoproteínas de Hemaglutininação de Vírus da Influenza/administração & dosagem , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Vírus da Influenza A/química , Vírus da Influenza A/genética , Vírus da Influenza A/imunologia , Vírus da Influenza B/química , Camundongos , Infecções por Orthomyxoviridae/virologia , Receptores Fc/imunologia , Vacinação
14.
J Virol ; 90(2): 851-61, 2016 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-26512088

RESUMO

UNLABELLED: Between November 2013 and February 2014, China reported three human cases of H10N8 influenza virus infection in the Jiangxi province, two of which were fatal. Using hybridoma technology, we isolated a panel of H10- and N8-directed monoclonal antibodies (MAbs) and further characterized the binding reactivity of these antibodies (via enzyme-linked immunosorbent assay) to a range of purified virus and recombinant protein substrates. The H10-directed MAbs displayed functional hemagglutination inhibition (HI) and neutralization activity, and the N8-directed antibodies displayed functional neuraminidase inhibition (NI) activity against H10N8. Surprisingly, the HI-reactive H10 antibodies, as well as a previously generated, group 2 hemagglutinin (HA) stalk-reactive antibody, demonstrated NI activity against H10N8 and an H10N7 strain; this phenomenon was absent when virus was treated with detergent, suggesting the anti-HA antibodies inhibited neuraminidase enzymatic activity through steric hindrance. We tested the prophylactic efficacy of one representative H10-reactive, N8-reactive, and group 2 HA stalk-reactive antibody in vivo using a BALB/c challenge model. All three antibodies were protective at a high dose (5 mg/kg). At a low dose (0.5 mg/kg), only the anti-N8 antibody prevented weight loss. Together, these data suggest that antibody targets other than the globular head domain of the HA may be efficacious in preventing influenza virus-induced morbidity and mortality. IMPORTANCE: Avian H10N8 and H10N7 viruses have recently crossed the species barrier, causing morbidity and mortality in humans and other mammals. Although these reports are likely isolated incidents, it is possible that more cases may emerge in future winter seasons, similar to H7N9. Furthermore, regular transmission of avian influenza viruses to humans increases the risk of adaptive mutations and reassortment events, which may result in a novel virus with pandemic potential. Currently, no specific therapeutics or vaccines are available against the H10N8 influenza virus subtype. We generated a panel of H10- and N8-reactive MAbs. Although these antibodies may practically be developed into therapeutic agents, characterizing the protective potential of MAbs that have targets other than the HA globular head domain will provide insight into novel antibody-mediated mechanisms of protection and help to better understand correlates of protection for influenza A virus infection.


Assuntos
Anticorpos Monoclonais/administração & dosagem , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Antivirais/administração & dosagem , Imunização Passiva/métodos , Fatores Imunológicos/administração & dosagem , Vírus da Influenza A Subtipo H10N8/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Peso Corporal , Modelos Animais de Doenças , Feminino , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Fatores Imunológicos/imunologia , Pulmão/virologia , Camundongos Endogâmicos BALB C , Neuraminidase/imunologia , Testes de Neutralização , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Análise de Sobrevida , Resultado do Tratamento , Carga Viral , Proteínas Virais/imunologia
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