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1.
PLoS Pathog ; 15(12): e1008109, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31856206

RESUMO

Across decades of co-circulation in humans, influenza A subtypes H1N1 and H3N2 have caused seasonal epidemics characterized by different age distributions of cases and mortality. H3N2 causes the majority of severe, clinically attended cases in high-risk elderly cohorts, and the majority of overall deaths, whereas H1N1 causes fewer deaths overall, and cases shifted towards young and middle-aged adults. These contrasting age profiles may result from differences in childhood imprinting to H1N1 and H3N2 or from differences in evolutionary rate between subtypes. Here we analyze a large epidemiological surveillance dataset to test whether childhood immune imprinting shapes seasonal influenza epidemiology, and if so, whether it acts primarily via homosubtypic immune memory or via broader, heterosubtypic memory. We also test the impact of evolutionary differences between influenza subtypes on age distributions of cases. Likelihood-based model comparison shows that narrow, within-subtype imprinting shapes seasonal influenza risk alongside age-specific risk factors. The data do not support a strong effect of evolutionary rate, or of broadly protective imprinting that acts across subtypes. Our findings emphasize that childhood exposures can imprint a lifelong immunological bias toward particular influenza subtypes, and that these cohort-specific biases shape epidemic age distributions. As a consequence, newer and less "senior" antibody responses acquired later in life do not provide the same strength of protection as responses imprinted in childhood. Finally, we project that the relatively low mortality burden of H1N1 may increase in the coming decades, as cohorts that lack H1N1-specific imprinting eventually reach old age.


Assuntos
Epidemias , Influenza Humana/epidemiologia , Influenza Humana/imunologia , Influenza Humana/virologia , Adulto , Criança , Feminino , Humanos , Memória Imunológica/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Masculino
2.
Artigo em Inglês | MEDLINE | ID: mdl-31738866

RESUMO

The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at sites in all jurisdictions in Australia. This report summarises the epidemiology of hospitalisations with laboratory-confirmed influenza during the 2018 influenza season. In this observational surveillance system, cases were defined as patients admitted to any of the 17 sentinel hospitals with influenza confirmed by nucleic acid detection. Data were also collected on a frequency-matched control group of influenza-negative patients admitted with acute respiratory infection. During the period 3 April to 31 October 2018 (the 2018 influenza season), 769 patients were admitted with confirmed influenza to one of 17 FluCAN sentinel hospitals. Of these, 30% were elderly (≥65 years), 28% were children (<16 years), 6.4% were Aboriginal and Torres Strait Islander peoples, 2.2% were pregnant and 66% had chronic comorbidities. A small proportion of FluCAN admissions were due to influenza B (13%). Estimated vaccine coverage was 77% in the elderly (≥65 years), 45% in non-elderly adults with medical comorbidities and 26% in children (<16 years) with medical comorbidities. The estimated vaccine effectiveness (VE) in the target population was 52% (95% CI: 37%, 63%). There were a smaller number of hospital admissions detected with confirmed influenza in this national observational surveillance system in 2018 than in 2017, with the demographic profile reflecting the change in circulating subtype from A/H3N2 to A/H1N1.


Assuntos
Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/epidemiologia , Cobertura Vacinal , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Relatórios Anuais como Assunto , Austrália/epidemiologia , Estudos de Casos e Controles , Feminino , Hospitalização , Hospitais , Humanos , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Gravidez , Vigilância de Evento Sentinela , Adulto Jovem
3.
Pediatrics ; 144(4)2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31477606

RESUMO

This statement updates the recommendations of the American Academy of Pediatrics for the routine use of influenza vaccines and antiviral medications in the prevention and treatment of influenza in children during the 2019-2020 season. The American Academy of Pediatrics continues to recommend routine influenza immunization of all children without medical contraindications, starting at 6 months of age. Any licensed, recommended, age-appropriate vaccine available can be administered, without preference of one product or formulation over another. Antiviral treatment of influenza with any licensed, recommended, age-appropriate influenza antiviral medication continues to be recommended for children with suspected or confirmed influenza, particularly those who are hospitalized, have severe or progressive disease, or have underlying conditions that increase their risk of complications of influenza.


Assuntos
Antivirais/administração & dosagem , Vacinas contra Influenza/administração & dosagem , Influenza Humana/tratamento farmacológico , Influenza Humana/prevenção & controle , Adolescente , Fatores Etários , Antivirais/efeitos adversos , Aleitamento Materno , Causas de Morte , Criança , Criança Hospitalizada , Pré-Escolar , Contraindicações , Progressão da Doença , Farmacorresistência Viral , Hipersensibilidade a Ovo , Feminino , Humanos , Hospedeiro Imunocomprometido , Lactente , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/efeitos adversos , Influenza Humana/complicações , Influenza Humana/epidemiologia , Pediatria , Gravidez , Estados Unidos/epidemiologia , Vacinas de Produtos Inativados/administração & dosagem
4.
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
5.
Nat Commun ; 10(1): 3422, 2019 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-31366921

RESUMO

Severe influenza infection has no effective treatment available. One of the key barriers to developing host-directed therapy is a lack of reliable prognostic factors needed to guide such therapy. Here, we use a network analysis approach to identify host factors associated with severe influenza and fatal outcome. In influenza patients with moderate-to-severe diseases, we uncover a complex landscape of immunological pathways, with the main changes occurring in pathways related to circulating neutrophils. Patients with severe disease display excessive neutrophil extracellular traps formation, neutrophil-inflammation and delayed apoptosis, all of which have been associated with fatal outcome in animal models. Excessive neutrophil activation correlates with worsening oxygenation impairment and predicted fatal outcome (AUROC 0.817-0.898). These findings provide new evidence that neutrophil-dominated host response is associated with poor outcomes. Measuring neutrophil-related changes may improve risk stratification and patient selection, a critical first step in developing host-directed immune therapy.


Assuntos
Armadilhas Extracelulares/imunologia , Influenza Humana/imunologia , Influenza Humana/patologia , Ativação de Neutrófilo/imunologia , Neutrófilos/imunologia , Ciclo Celular/imunologia , Feminino , Expressão Gênica/genética , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/imunologia , Vírus da Influenza B/isolamento & purificação , Influenza Humana/mortalidade , Pulmão/imunologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Respiração Artificial , Insuficiência Respiratória/mortalidade , Insuficiência Respiratória/patologia , Insuficiência Respiratória/virologia
6.
PLoS Comput Biol ; 15(8): e1007294, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31425503

RESUMO

The strength and breadth of an individual's antibody repertoire is an important predictor of their response to influenza infection or vaccination. Although progress has been made in understanding qualitatively how repeated exposures shape the antibody mediated immune response, quantitative understanding remains limited. We developed a set of mathematical models describing short-term antibody kinetics following influenza infection or vaccination and fit them to haemagglutination inhibition (HI) titres from 5 groups of ferrets which were exposed to different combinations of trivalent inactivated influenza vaccine (TIV with or without adjuvant), A/H3N2 priming inoculation and post-vaccination A/H1N1 inoculation. We fit models with various immunological mechanisms that have been empirically observed but have not previously been included in mathematical models of antibody landscapes, including: titre ceiling effects, antigenic seniority and exposure-type specific cross reactivity. Based on the parameter estimates of the best supported models, we describe a number of key immunological features. We found quantifiable differences in the degree of homologous and cross-reactive antibody boosting elicited by different exposure types. Infection and adjuvanted vaccination generally resulted in strong, broadly reactive responses whereas unadjuvanted vaccination resulted in a weak, narrow response. We found that the order of exposure mattered: priming with A/H3N2 improved subsequent vaccine response, and the second dose of adjuvanted vaccination resulted in substantially greater antibody boosting than the first. Either antigenic seniority or a titre ceiling effect were included in the two best fitting models, suggesting a role for a mechanism describing diminishing antibody boosting with repeated exposures. Although there was considerable uncertainty in our estimates of antibody waning parameters, our results suggest that both short and long term waning were present and would be identifiable with a larger set of experiments. These results highlight the potential use of repeat exposure animal models in revealing short-term, strain-specific immune dynamics of influenza.


Assuntos
Anticorpos Antivirais/sangue , Furões/imunologia , Vacinas contra Influenza/administração & dosagem , Modelos Imunológicos , Infecções por Orthomyxoviridae/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Biologia Computacional , Reações Cruzadas , Modelos Animais de Doenças , Humanos , Imunização Secundária , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Cinética , Infecções por Orthomyxoviridae/virologia , Vacinas de Produtos Inativados/administração & dosagem
7.
Biomed Environ Sci ; 32(7): 531-540, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31331437

RESUMO

OBJECTIVE: To evaluate the effect of intranasal immunization with CTA1-DD as mucosal adjuvant combined with H3N2 split vaccine. METHODS: Mice were immunized intranasally with PBS (negative control), or H3N2 split vaccine (3 µg/mouse) alone, or CTA1-DD (5 µg/mouse) alone, or H3N2 split vaccine (3 µg/mouse) plus CTA1-DD (5 µg/mouse). Positive control mice were immunized intramuscularly with H3N2 split vaccine (3 µg/mouse) and alum adjuvant. All the mice were immunized twice, two weeks apart. Then sera and mucosal lavages were collected. The specific HI titers, IgM, IgG, IgA, and IgG subtypes were examined by ELISA. IFN-γ and IL-4 were test by ELISpot. In addition, two weeks after the last immunization, surivival after H3N2 virus lethal challenge was measured. RESULTS: H3N2 split vaccine formulated with CTA1-DD could elicit higher IgM, IgG and hemagglutination inhibition titers in sera. Furthermore, using CTA1-DD as adjuvant significantly improved mucosal secretory IgA titers in bronchoalveolar lavages and vaginal lavages. Meanwhile this mucosal adjuvant could enhance Th-1-type responses and induce protective hemagglutination inhibition titers. Notably, the addition of CTA1-DD to split vaccine provided 100% protection against lethal infection by the H3N2 virus. CONCLUSION: CTA1-DD could promote mucosal, humoral and cell-mediated immune responses, which supports the further development of CTA1-DD as a mucosal adjuvant for mucosal vaccines.


Assuntos
Adjuvantes Imunológicos , Toxina da Cólera , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza , Proteínas Recombinantes de Fusão , Administração Intranasal , Animais , Feminino , Imunidade Humoral , Camundongos Endogâmicos BALB C , Mucosa Nasal/imunologia , Distribuição Aleatória
8.
Nutrients ; 11(7)2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31336756

RESUMO

Antenatal milk anti-influenza antibodies may provide additional protection to newborns until they are able to produce their own antibodies. To evaluate the relative abundance of milk, we studied the antibodies specific to influenza A in feeds and gastric contents and stools from preterm infants fed mother's own breast milk (MBM) and donor breast milk (DBM). Feed (MBM or DBM) and gastric contents (MBM or DBM at 1 h post-ingestion) and stool samples (MBM/DBM at 24 h post-ingestion) were collected, respectively, from 20 preterm (26-36 weeks gestational age) mother-infant pairs at 8-9 days and 21-22 days of postnatal age. Samples were analyzed via ELISA for anti-H1N1 hemagglutinin (anti-H1N1 HA) and anti-H3N2 neuraminidase (anti-H3N2 NA) specificity across immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) isotypes. The relative abundance of influenza A-specific IgA in feeds and gastric contents were higher in MBM than DBM at 8-9 days of postnatal age but did not differ at 21-22 days. Anti-influenza A-specific IgM was higher in MBM than in DBM at both postnatal times in feed and gastric samples. At both postnatal times, anti-influenza A-specific IgG was higher in MBM than DBM but did not differ in gastric contents. Gastric digestion reduced anti-H3N2 NA IgG from MBM at 21-22 days and from DBM at 8-9 days of lactation, whereas other anti-influenza A antibodies were not digested at either postnatal times. Supplementation of anti-influenza A-specific antibodies in DBM may help reduce the risk of influenza virus infection. However, the effective antibody dose required to induce a significant protective effect remains unknown.


Assuntos
Imunoglobulina A/química , Imunoglobulina G/química , Imunoglobulina M/química , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Leite Humano/química , Anticorpos Antivirais/química , Fezes/química , Feminino , Conteúdo Gastrointestinal/química , Humanos , Imunidade Materno-Adquirida , Recém-Nascido Prematuro , Mães
9.
BMC Infect Dis ; 19(1): 656, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31337344

RESUMO

BACKGROUND: The immune response to seasonal influenza vaccines decreases with advancing age. Therefore, an adjuvanted inactivated trivalent influenza vaccine (Fluad®) exists for elderly individuals. Fluad® is more immunogenic and efficacious than conventional influenza vaccines. However, the immune response varies and may still result in high frequencies of poor responders. Therefore, we aimed to a) examine the prevalence of a weak response to Fluad® and b) identify potential risk factors. METHODS: A prospective population-based study among individuals 65-80 years old was conducted in 2015/2016 in Hannover, Germany (n = 200). Hemagglutination-inhibition titers 21 days after vaccination with Fluad® served as indicator of vaccine responsiveness. RESULTS: The percentage of vaccinees with an inadequate vaccine response varied depending on the influenza strain: it was lowest for H3N2 (13.5%; 95% CI, 9.4-18.9%), intermediate for B strain (37.0%; 30.6-43.9%), and highest for H1N1 (49.0%; 42.2-55.9%). The risk of a weak response to the influenza A H1N1 strain was independently associated with self-reported diabetes (AOR, 4.64; 95% CI, 1.16-18.54), a history of herpes zoster (2.27; 1.01-5.10) and, to a much lesser extent, increasing age (change per year, 1.08; 0.99-1.16). In addition, herpes zoster was the only risk factor for a weak response to the H3N2 antigen (AOR, 3.12; 1.18-8.23). We found no significant association between sex, Body Mass Index, cancer, hypertension, heart attack and CMV seropositivity and a weak response to these two influenza A antigens. Despite its occurence in over one third of vaccinees, none of the variables examined proved to be risk factors for a weak response to the B antigen. CONCLUSIONS: A considerable proportion of elderly individuals displayed a weak vaccine response to this adjuvanted seasonal influenza vaccine and further efforts are thus needed to improve immune responses to influenza vaccination among the elderly. Diabetes and herpes zoster were identified as potentially modifiable risk factors for a poor vaccine response against influenza A antigens, but the results also reveal the need for broader investigations to identify risk factors for inadequate responses to influenza B antigens. TRIAL REGISTRATION: No. NCT02362919 (ClinicalTrials.gov, date of registration: 09.02.2015).


Assuntos
Diabetes Mellitus/imunologia , Herpes Zoster/imunologia , Imunidade Humoral , Vacinas contra Influenza/imunologia , Adjuvantes Imunológicos/farmacologia , Idoso , Idoso de 80 Anos ou mais , Antígenos Virais/imunologia , Feminino , Alemanha , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/efeitos adversos , Vacinas contra Influenza/farmacologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Masculino , Estudos Prospectivos , Estações do Ano , Autorrelato
10.
Nat Commun ; 10(1): 3338, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31350391

RESUMO

Several vaccines are approved in the United States for seasonal influenza vaccination every year. Here we compare the impact of repeat influenza vaccination on hemagglutination inhibition (HI) titers, antibody binding and affinity maturation to individual hemagglutinin (HA) domains, HA1 and HA2, across vaccine platforms. Fold change in HI and antibody binding to HA1 trends higher for H1N1pdm09 and H3N2 but not against B strains in groups vaccinated with FluBlok compared with FluCelvax and Fluzone. Antibody-affinity maturation occurs against HA1 domain of H1N1pdm09, H3N2 and B following vaccination with all vaccine platforms, but not against H1N1pdm09-HA2. Importantly, prior year vaccination of subjects receiving repeat vaccinations demonstrated reduced antibody-affinity maturation to HA1 of all three influenza virus strains irrespective of the vaccine platform. This study identifies an important impact of repeat vaccination on antibody-affinity maturation following vaccination, which may contribute to lower vaccine effectiveness of seasonal influenza vaccines in humans.


Assuntos
Afinidade de Anticorpos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Adolescente , Adulto , Anticorpos Antivirais/imunologia , Criança , Pré-Escolar , Feminino , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/administração & dosagem , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Lactente , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/genética , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/genética , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Vacinação , Adulto Jovem
12.
Virol Sin ; 34(5): 583-591, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31240620

RESUMO

Conventional influenza vaccines need to be designed and manufactured yearly. However, they occasionally provide poor protection owing to antigenic mismatch. Hence, there is an urgent need to develop universal vaccines against influenza virus. Using nucleoprotein (NP) and extracellular domain of matrix protein 2 (M2e) genes from the influenza A virus A/Beijing/30/95 (H3N2), we constructed four recombinant vaccinia virus-based influenza vaccines carrying NP fused with one or four copies of M2e genes in different orders. The recombinant vaccinia viruses were used to immunize BALB/C mice. Humoral and cellular responses were measured, and then the immunized mice were challenged with the influenza A virus A/Puerto Rico/8/34 (PR8). NP-specific humoral response was elicited in mice immunized with recombinant vaccinia viruses carrying full-length NP, while robust M2e-specific humoral response was elicited only in the mice immunized with recombinant vaccinia viruses carrying multiple copies of M2e. All recombinant viruses elicited NP- and M2e-specific cellular immune responses in mice. Only immunization with RVJ-4M2eNP induced remarkably higher levels of IL-2 and IL-10 cytokines specific to M2e. Furthermore, RVJ-4M2eNP immunization provided the highest cross-protection in mice challenged with 20 MLD50 of PR8. Therefore, the cross-protection potentially correlates with both NP and M2e-specific humoral and cellular immune responses induced by RVJ-4M2eNP, which expresses a fusion antigen of full-length NP preceded by four M2e repeats. These results suggest that the rational fusion of NP and multiple M2e antigens is critical toward inducing protective immune responses, and the 4M2eNP fusion antigen may be employed to develop a universal influenza vaccine.


Assuntos
Proteção Cruzada , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Nucleoproteínas/imunologia , Vaccinia/genética , Proteínas da Matriz Viral/imunologia , Animais , Anticorpos Antivirais/sangue , Feminino , Humanos , Imunidade Celular , Imunidade Humoral , Imunização , Vírus da Influenza A Subtipo H3N2/genética , Vacinas contra Influenza/genética , Camundongos Endogâmicos BALB C , Nucleoproteínas/genética , Infecções por Orthomyxoviridae/prevenção & controle , Organismos Livres de Patógenos Específicos , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia , Proteínas da Matriz Viral/genética
13.
Cell Host Microbe ; 25(6): 836-844.e5, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31151913

RESUMO

Egg-based seasonal influenza vaccines are the major preventive countermeasure against influenza virus. However, their effectiveness can be compromised when antigenic changes arise from egg-adaptive mutations on influenza hemagglutinin (HA). The L194P mutation is commonly observed in egg-based H3N2 vaccine seed strains and significantly alters HA antigenicity. An approach to prevent L194P would therefore be beneficial. We show that emergence of L194P during egg passaging can be impeded by preexistence of a G186V mutation, revealing strong incompatibility between these mutations. X-ray structures illustrate that individual G186V and L194P mutations have opposing effects on the HA receptor-binding site (RBS), and when both G186V and L194P are present, the RBS is severely disrupted. Importantly, wild-type HA antigenicity is maintained with G186V, but not L194P. Our results demonstrate that these epistatic interactions can be used to prevent the emergence of mutations that adversely alter antigenicity during egg adaptation.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H3N2/crescimento & desenvolvimento , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/genética , Vacinas contra Influenza/imunologia , Mutação de Sentido Incorreto , Adaptação Biológica , Animais , Antígenos Virais/química , Antígenos Virais/genética , Antígenos Virais/imunologia , Sítios de Ligação , Embrião de Galinha , Cristalografia por Raios X , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Vírus da Influenza A Subtipo H3N2/genética , Conformação Proteica , Tecnologia Farmacêutica/métodos , Cultura de Vírus/métodos
14.
Cell Host Microbe ; 25(6): 773-775, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31194938

RESUMO

The majority of influenza vaccines are produced in embryonated eggs, but mutations occur as human influenza A(H3N2) viruses adapt to grow in eggs. This can alter virus antigenicity. Wu et al. (2019) reveal that there are two mutually exclusive pathways for egg adaptation, which has potential implications for future egg-based influenza vaccines.


Assuntos
Vacinas contra Influenza , Influenza Humana , Humanos , Vírus da Influenza A Subtipo H3N2/imunologia , Mutação , Estações do Ano
15.
Cell Host Microbe ; 25(6): 827-835.e6, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31104946

RESUMO

Viral glycoproteins are under constant immune surveillance by a host's adaptive immune responses. Antigenic variation including glycan introduction or removal is among the mechanisms viruses have evolved to escape host immunity. Understanding how glycosylation affects immunodominance on complex protein antigens may help decipher underlying B cell biology. To determine how B cell responses can be altered by such modifications, we engineered glycans onto the influenza virus hemagglutinin (HA) and characterized the molecular features of the elicited humoral immunity in mice. We found that glycan addition changed the initially diverse antibody repertoire into an epitope-focused, genetically restricted response. Structural analyses showed that one antibody gene family targeted a previously subdominant, occluded epitope at the head interface. Passive transfer of this antibody conferred Fc-dependent protection to influenza virus-challenged mice. These results have potential implications for next-generation viral vaccines aimed at directing B cell responses to preferred epitope(s).


Assuntos
Anticorpos Antivirais/imunologia , Epitopos/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Polissacarídeos/metabolismo , Animais , Anticorpos Antivirais/metabolismo , Cristalografia por Raios X , Epitopos/química , Epitopos/genética , Epitopos/metabolismo , Glicosilação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Imunização Passiva , Vírus da Influenza A Subtipo H3N2/genética , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/prevenção & controle , Ligação Proteica , Conformação Proteica , Análise de Sobrevida
16.
Immunity ; 50(5): 1172-1187.e7, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31076359

RESUMO

Although viral infections elicit robust interferon-γ (IFN-γ) and long-lived antibody-secreting cell (ASC) responses, the roles for IFN-γ and IFN-γ-induced transcription factors (TFs) in ASC development are unclear. We showed that B cell intrinsic expression of IFN-γR and the IFN-γ-induced TF T-bet were required for T-helper 1 cell-induced differentiation of B cells into ASCs. IFN-γR signaling induced Blimp1 expression in B cells but also initiated an inflammatory gene program that, if not restrained, prevented ASC formation. T-bet did not affect Blimp1 upregulation in IFN-γ-activated B cells but instead regulated chromatin accessibility within the Ifng and Ifngr2 loci and repressed the IFN-γ-induced inflammatory gene program. Consistent with this, B cell intrinsic T-bet was required for formation of long-lived ASCs and secondary ASCs following viral, but not nematode, infection. Therefore, T-bet facilitates differentiation of IFN-γ-activated inflammatory effector B cells into ASCs in the setting of IFN-γ-, but not IL-4-, induced inflammatory responses.


Assuntos
Linfócitos B/imunologia , Interferon gama/imunologia , Receptores de Interferon/metabolismo , Proteínas com Domínio T/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Células Produtoras de Anticorpos/imunologia , Linfócitos B/citologia , Diferenciação Celular/imunologia , Células Cultivadas , Cromatina/metabolismo , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nematospiroides dubius/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Fator 1 de Ligação ao Domínio I Regulador Positivo/biossíntese , Infecções por Strongylida/imunologia , Infecções por Strongylida/parasitologia , Proteínas com Domínio T/genética
17.
Microbiol Immunol ; 63(6): 223-228, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31070266

RESUMO

Assessment of cell-mediated immunity (CMI) may be critical to evaluating the ability of individuals to protect themselves against influenza virus infection. However, it has been difficult to evaluate CMI because no simple means of measuring it is currently available. The aim of this study was to compare the performance of a CMI measurement method developed by us, which involves reacting whole blood with antigen, with the conventional method, which is based on isolating peripheral blood mononuclear cells (PBMCs). Correlations between these methods before and after vaccination of 26 healthy adults (aged 28-58 years; 12 men and 14 women) were assessed and changes in CMI after influenza vaccination in PBMCs cultured with antigen for 48 and 96 hr and whole blood cultured with antigen for 48 hr were studied. Results of CMI measurement using whole blood on Day 2 and PBMCs on Day 4 were found to be correlated. Spearman's correlation coefficients with four antigens (A [H1N1], A [H3N2], B [Yamagata lineage], and B [Victoria lineage]) before vaccination were 0.55, 0.61, 0.58, and 0.70, respectively and 0.40, 0.45, 0.62, and 0.52, respectively, after vaccination. CMI was detected sooner when whole blood was reacted with antigen than when PBMCs were reacted with antigen. The rate of positive reaction of influenza A (H1N1 and H3N2) in whole blood on Day 2 was higher than that in PBMCs on Day 2. Our method is simple and may be useful for vaccine development because it can measure CMI in a small amount of blood without separating off PBMCs.


Assuntos
Imunidade Celular/imunologia , Vacinas contra Influenza/sangue , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Leucócitos Mononucleares/imunologia , Adulto , Anticorpos Antivirais/sangue , Antígenos Virais , Feminino , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Masculino , Pessoa de Meia-Idade , Vacinação
18.
BMC Public Health ; 19(1): 487, 2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31046725

RESUMO

BACKGROUND: The Global Influenza Hospital Surveillance Network (GIHSN) aims to determine the burden of severe influenza disease and Influenza Vaccine Effectiveness (IVE). This is a prospective, active surveillance and hospital-based epidemiological study to collect epidemiological data in the GIHSN. In the 2016-2017 influenza season, 15 sites in 14 countries participated in the GIHSN, although the analyses could not be performed in 2 sites. A common core protocol was used in order to make results comparable. Here we present the results of the GIHSN 2016-2017 influenza season. METHODS: A RT-PCR test was performed to all patients that accomplished the requirements detailed on a common core protocol. Patients admitted were included in the study after signing the informed consent, if they were residents, not institutionalised, not discharged in the previous 30 days from other hospitalisation with symptoms onset within the 7 days prior to admission. Patients 5 years old or more must also complied the Influenza-Like Illness definition. A test negative-design was implemented to perform IVE analysis. IVE was estimated using a logistic regression model, with the formula IVE = (1-aOR) × 100, where aOR is the adjusted Odds Ratio comparing cases and controls. RESULTS: Among 21,967 screened patients, 10,140 (46.16%) were included, as they accomplished the inclusion criteria, and tested, and therefore 11,827 (53.84%) patients were excluded. Around 60% of all patients included with laboratory results were recruited at 3 sites. The predominant strain was A(H3N2), detected in 63.6% of the cases (1840 patients), followed by B/Victoria, in 21.3% of the cases (618 patients). There were 2895 influenza positive patients (28.6% of the included patients). A(H1N1)pdm09 strain was mainly found in Mexico. IVE could only be performed in 6 sites separately. Overall IVE was 27.24 (95% CI 15.62-37.27. Vaccination seemed to confer better protection against influenza B and in people 2-4 years, or 85 years old or older. The aOR for hospitalized and testing positive for influenza was 3.02 (95% CI 1.59-5.76) comparing pregnant with non-pregnant women. CONCLUSIONS: Vaccination prevented around 1 in 4 hospitalisations with influenza. Sparse numbers didn't allow estimating IVE in all sites separately. Pregnancy was found a risk factor for influenza, having 3 times more risk of being admitted with influenza for pregnant women.


Assuntos
Hospitalização/estatística & dados numéricos , Vacinas contra Influenza/uso terapêutico , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Vigilância de Evento Sentinela , Vacinação/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Saúde Global , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/imunologia , Masculino , Pessoa de Meia-Idade , Gravidez , Estações do Ano
19.
Biogerontology ; 20(4): 475-496, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31049769

RESUMO

The study examined sex-specificities in age-related changes in BALB/c mice IgG antibody responses to immunisation with trivalent inactivated split-virus influenza bulk. Aging diminished the total serum IgG antibody responses to H1N1 and H3N2 and B influenza virus antigens in mice of both sexes, but they remained greater in aged females. This sex difference in aged mice correlated with the greater post-immunisation increase in the frequency of spleen germinal centre (GC) B cells and more favourable T follicular regulatory (Tfr)/GC B cell ratio, as Tfr cells are suggested to control antibody production through suppression of glycolysis. The greater post-immunisation GC B cell response in aged females compared with males correlated with the greater proliferation of B cells and CD4+ cells in splenocyte cultures from aged females restimulated with inactivated split-virus influenza from the bulk. To support the greater post-immunisation increase in the frequency GC B cell in aged females was more favourable Tfr/T follicular helper (Tfh) cell ratio. Additionally, compared with aged males, in age-matched females the greater avidity of serum IgG antibodies was found. However, in aged females IgG2a/IgG1 antibody ratio, reflecting spleen Th1/Th2 cytokine balance, was shifted towards IgG1 when compared with age-matched male mice. This shift was ascribed to a more prominent decline in the titres of functionally important IgG2a antibodies in females with aging. The study suggest that biological sex should be considered as a variable in designing strategies to manipulate with immune outcome of immunisation in aged animals, and possibly, at very long distance, humans.


Assuntos
Envelhecimento/imunologia , Formação de Anticorpos/fisiologia , Centro Germinativo/imunologia , Imunoglobulina G , Fatores Etários , Animais , Feminino , Humanos , Imunidade Ativa/fisiologia , Imunoglobulina G/sangue , Imunoglobulina G/classificação , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fatores Sexuais
20.
Int J Infect Dis ; 85S: S18-S25, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31051279

RESUMO

OBJECTIVE: To assess the safety and immunogenicity of the MF59-adjuvanted seasonal trivalent inactivated influenza vaccine (aIIV3; Fluad) in children aged 6 months through 5 years who are at risk of influenza complications. METHODS: A retrospective analysis was performed to examine unsolicited adverse events (AEs) in an integrated dataset from six randomized clinical studies that compared aIIV3 with non-adjuvanted inactivated influenza vaccines (IIV3). The integrated safety set comprised 10 784 children, of whom 373 (3%) were at risk of influenza complications. RESULTS: The at-risk safety population comprised 373 children aged 6 months through 5 years: 179 received aIIV3 and 194 received non-adjuvanted IIV3 (128 subjects received a licensed IIV3). The most important risk factors were respiratory system illnesses (62-70%) and infectious and parasitic diseases (33-39%). During the treatment period, unsolicited AEs occurred in 54% of at-risk children and 55% of healthy children who received aIIV3; of those receiving licensed IIV3, 59% of at-risk and 62% of healthy subjects reported an unsolicited AE. The most common AEs were infections, including upper respiratory tract infection. Serious AEs (SAEs) were reported in <10% of at-risk subjects, and no vaccine-related SAEs were observed. In the immunogenicity subset (involving 103 participants from one study), geometric mean titers (GMTs) were approximately 2- to 3-fold higher with aIIV3 than with IIV3 for all three homologous strains (A/H1N1, A/H3N2, and B). Seroconversion rates were high for both aIIV3 (79-96%) and IIV3 (83-89%). CONCLUSIONS: In young children at risk of influenza complications, aIIV3 was well-tolerated and had a safety profile that was generally similar to that of non-adjuvanted IIV3. Similar to the not-at-risk population, the immune response in at-risk subjects receiving aIIV3 was increased over those receiving IIV3, suggesting aIIV3 is a valuable option in young children at risk of influenza complications.


Assuntos
Adjuvantes Imunológicos , Vacinas contra Influenza/efeitos adversos , Vacinas contra Influenza/imunologia , Polissorbatos , Esqualeno , Adjuvantes Imunológicos/efeitos adversos , Pré-Escolar , Feminino , Humanos , Imunogenicidade da Vacina , Lactente , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Influenza Humana/complicações , Influenza Humana/prevenção & controle , Masculino , Polissorbatos/efeitos adversos , Estudos Retrospectivos , Estações do Ano , Soroconversão , Esqualeno/efeitos adversos , Vacinas de Produtos Inativados/imunologia
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