RESUMO
UNLABELLED: Studies evaluating the immunogenicity of two pediatric tick-borne encephalitis virus (TBEV) vaccines have reported contradictory results. These vaccines are based on two different strains of the European TBEV subtype: FSME-Immun Junior is based on the Neudörfl (Nd) strain, whereas Encepur Children is based on the Karlsruhe (K23) strain. The antibody (Ab) response induced by these two vaccines might be influenced by antigenic differences in the envelope (E) protein, which is the major target of neutralizing antibodies. We used an established hybrid virus assay platform to compare the levels of induction of neutralizing antibodies against the two vaccine virus strains in children aged 1 to 11 years who received two immunizations with FSME-Immun Junior or Encepur Children. The influence of amino acid differences between the E proteins of the Nd and K23 vaccine strains was investigated by mutational analyses and three-dimensional computer modeling. FSME-Immun Junior induced 100% seropositivity and similar neutralizing antibody titers against hybrid viruses containing the TBEV E protein of the two vaccine strains. Encepur Children induced 100% seropositivity only against the hybrid virus containing the E protein of the homologous K23 vaccine strain. Antibody responses induced by Encepur Children to the hybrid virus containing the E protein of the heterologous Nd strain were substantially and significantly (P < 0.001) lower than those to the K23 vaccine strain hybrid virus. Structure-based mutational analyses of the TBEV E protein indicated that this is due to a mutation in the DI-DII hinge region of the K23 vaccine strain E protein which may have occurred during production of the vaccine seed virus and which is not present in any wild-type TBE viruses. IMPORTANCE: Our data suggest that there are major differences in the abilities of two European subtype pediatric TBEV vaccines to induce antibodies capable of neutralizing heterologous TBEV strains. This is a result of a mutation in the DI-DII hinge region of the E protein of the K23 vaccine virus strain used to manufacture Encepur Children which is not present in the Nd strain used to manufacture FSME-Immun Junior or in any other known naturally occurring TBEVs.
Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Vírus da Encefalite Transmitidos por Carrapatos/imunologia , Vacinas Virais/imunologia , Criança , Pré-Escolar , Análise Mutacional de DNA , Estabilidade de Medicamentos , Feminino , Instabilidade Genômica , Humanos , Lactente , Masculino , Modelos Moleculares , Mutação de Sentido Incorreto , Conformação Proteica , Tecnologia Farmacêutica , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Vacinas Virais/administração & dosagemRESUMO
BACKGROUND: Children are highly vulnerable to infection with novel influenza viruses. It is essential to develop candidate pandemic influenza vaccines that are safe and effective in the pediatric population. METHODS: Infants and children aged 6-35 months and 3-8 years, respectively, were randomized to receive 2 immunizations with a 7.5-µg or 3.75-µg hemagglutinin (HA) dose of a nonadjuvanted whole-virus A/Vietnam(H5N1) vaccine; adolescents aged 9-17 years received a 7.5-µg dose only. A subset of participants received a booster immunization with an A/Indonesia(H5N1) vaccine approximately 1 year later. HA and neuraminidase antibody responses were assessed. RESULTS: Vaccination was safe and well tolerated; adverse reactions were transient and predominantly mild. Two immunizations with the 7.5-µg dose of A/Vietnam vaccine induced virus microneutralization (MN) titers of ≥1:20 against the A/Vietnam strain in 68.8%-85.4% of participants in the different age groups. After the booster, 93.1%-100% of participants achieved MN titers of ≥1:20 against the A/Vietnam and A/Indonesia strains. Neuraminidase-inhibiting antibodies were induced in ≥90% of participants after 2 immunizations with the 7.5 µg A/Vietnam vaccine and in 100% of participants after the booster. CONCLUSIONS: A whole-virus influenza A(H5N1) vaccine is suitable for prepandemic or pandemic immunization in a pediatric population. CLINICAL TRIALS REGISTRATION: NCT01052402.
Assuntos
Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/administração & dosagem , Adolescente , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Criança , Pré-Escolar , Chlorocebus aethiops , Feminino , Humanos , Lactente , Vacinas contra Influenza/efeitos adversos , Vacinas contra Influenza/imunologia , Masculino , Células VeroRESUMO
BACKGROUND: Convalescent plasma and fractionated immunoglobulins have been suggested as prophylactic or therapeutic interventions during an influenza pandemic. FINDINGS: Intravenous immunoglobulin (IVIG) preparations manufactured from human plasma collected before the 2009 H1N1 influenza pandemic, and post-pandemic hyperimmune (H)-IVIG preparations were characterized with respect to hemagglutination inhibition (HI), microneutralization (MN) and neuraminidase-inhibiting (NAi) antibody titers against pandemic H1N1 (pH1N1) and seasonal H1N1 (sH1N1) viruses. The protective efficacy of the IVIG and H-IVIG preparations was evaluated in a SCID mouse challenge model.Substantial levels of HI, MN and NAi antibodies against pH1N1 (GMTs 1:45, 1:204 and 1: 727, respectively) and sH1N1 (GMTs 1:688, 1:4,946 and 1:312, respectively) were present in pre-pandemic IVIG preparations. In post-pandemic H-IVIG preparations, HI, MN and NAi antibody GMTs against pH1N1 were 1:1,280, 1:11,404 and 1:2,488 (28-, 56- and 3.4-fold enriched), respectively, compared to pre-pandemic IVIG preparations (p < 0.001). Post-pandemic H-IVIG (HI titer 1:1,280) provided complete protection from lethality of SCID mice against pH1N1 challenge (100% of mice survived for 29 days post-challenge). Pre-pandemic IVIG (HI titer 1:70) did not provide significant protection against pH1N1 challenge (50% of mice survived 29 days post-challenge compared to 40% survival in the buffer control group). There was a highly significant correlation between circulating in vivo HI and MN antibody titers and survival (p < 0001). CONCLUSION: The substantial enrichment of HA- and NA-specific antibodies in H-IVIG and the efficacious protection of SCID mice against challenge with pH1N1 suggests H-IVIG as a promising intervention against pandemic influenza for immunocompromised patients and other risk groups.
Assuntos
Anticorpos Antivirais/administração & dosagem , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Imunoglobulinas Intravenosas/administração & dosagem , Vírus da Influenza A Subtipo H1N1/imunologia , Neuraminidase/antagonistas & inibidores , Infecções por Orthomyxoviridae/prevenção & controle , Proteínas Virais/antagonistas & inibidores , Animais , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Hospedeiro Imunocomprometido , Camundongos , Camundongos SCID , Neuraminidase/imunologia , Análise de Sobrevida , Resultado do Tratamento , Proteínas Virais/imunologiaRESUMO
BACKGROUND: Current knowledge of the consistency of protection induced by seasonal influenza vaccines over the duration of a full influenza season is limited, and little is known about the clinical course of disease in individuals who become infected despite vaccination. METHODS: Data from a randomized double-blind placebo-controlled clinical trial undertaken in healthy young adults in the 2008-2009 influenza season were used to investigate the weekly cumulative efficacy of a Vero cell culture-derived influenza vaccine. In addition, the duration and severity of disease in vaccine and placebo recipients with cell culture-confirmed influenza infection were compared. RESULTS: Vaccine efficacy against matching strains was consistently high (73%-82%) throughout the study, including the entire period of the influenza season during which influenza activity was above the epidemic threshold. Vaccine efficacy was also consistent (68%-83%) when calculated for all strains, irrespective of antigenic match. Vaccination also ameliorated disease symptoms when infection was not prevented. Bivariate analysis of duration and severity showed a significant amelioration of myalgia (P = .003), headache (P = .025), and fatigue (P = .013) in infected vaccinated subjects compared with placebo. Cough (P = .143) and oropharyngeal pain (P = .083) were also reduced in infected vaccinated subjects. CONCLUSIONS: A Vero cell culture-derived influenza vaccine provides consistently high levels of protection against cell culture-confirmed infection by seasonal influenza virus and significantly reduces the duration and severity of disease in those individuals in which infection is not prevented. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov NCT00566345.
Assuntos
Vacinas contra Influenza/imunologia , Influenza Humana/patologia , Influenza Humana/prevenção & controle , Adulto , Animais , Biotecnologia/métodos , Técnicas de Cultura de Células/métodos , Chlorocebus aethiops , Método Duplo-Cego , Humanos , Vacinas contra Influenza/administração & dosagem , Pessoa de Meia-Idade , Placebos/administração & dosagem , Índice de Gravidade de Doença , Tecnologia Farmacêutica/métodos , Fatores de Tempo , Células Vero , Adulto JovemRESUMO
BACKGROUND: The recent advent of murine leukaemia virus (MLV)-based replication-competent retroviral (RCR) vector technology has provided exciting new tools for gene delivery, albeit the advances in vector efficiency which have been realized are also accompanied by a set of fresh challenges. The expression of additional transgene sequences, for example, increases the length of the viral genome, which can lead to reductions in replication efficiency and in turn to vector genome instability. This necessitates efforts to analyse the rate and mechanism of recombinant emergence during the replication of such vectors to provide data which should contribute to improvements in RCR vector design. RESULTS: In this study, we have performed detailed molecular analyses on packaged vector genomes and proviral DNA following propagation of MLV-based RCR vectors both in cell culture and in pre-formed subcutaneous tumours in vivo. The effects of strain of MLV, transgene position and host cell type on the rate of emergence of vector recombinants were quantitatively analysed by applying real-time PCR and real-time RT-PCR assays. Individual mutants were further characterized by PCR, and nucleotide sequence and structural motifs associated with these mutants were determined by sequencing. Our data indicate that virus strain, vector design and host cell influence the rate of emergence of predominating vector mutants, but not the underlying recombination mechanisms in vitro. In contrast, however, differences in the RNA secondary structural motifs associated with sequenced mutants emerging in cell culture and in solid tumours in vivo were observed. CONCLUSION: Our data provide further evidence that MLV-based RCR vectors based on the Moloney strain of MLV and containing the transgene cassette in the 3' UTR region are superior to those based on Akv-MLV and/or containing the transgene cassette in the U3 region of the LTR. The observed discrepancies between the data obtained in solid tumours in vivo and our own and previously published data from infected cells in vitro demonstrates the importance of evaluating vectors designed for use in cancer gene therapy in vivo as well as in vitro.
Assuntos
Vetores Genéticos/genética , Recombinação Genética/genética , Retroviridae/genética , Deleção de Sequência/genética , Replicação Viral/genética , Animais , Sequência de Bases , Linhagem Celular , Linhagem Celular Tumoral , Vetores Genéticos/metabolismo , Humanos , Masculino , Camundongos , Camundongos Nus , Dados de Sequência Molecular , Células NIH 3T3 , Retroviridae/metabolismoRESUMO
Rous sarcoma virus (RSV) can be used for the simple generation of high-titer replication-competent retroviral (RCR) vectors. Retroviruses undergo frequent genomic recombination, however, and vectors with reduced replication kinetics are rapidly overgrown by mutant forms. Vector design is hence critical to vector efficacy. In this study, two different designs of RSV-based RCR vectors were evaluated. Vectors in which transgene expression was facilitated by the v-src splice acceptor were revealed to have greatly reduced replication kinetics and genomic stability in comparison to vectors in which transgene expression was mediated by an internal ribosome entry site in the 3' untranslated region.
Assuntos
Vetores Genéticos , Instabilidade Genômica , Sítios de Splice de RNA , Proteínas Recombinantes/biossíntese , Vírus do Sarcoma de Rous/genética , Transgenes , Proteínas Recombinantes/genéticaRESUMO
The principle of using suicide genes for gene directed enzyme prodrug therapy (GDEPT) of cancer has gained increasing significance during the 20 years since its inception. The astute application of suitable GDEPT systems should permit tumour ablation in the absence of off-target toxicity commonly associated with classical chemotherapy, a hypothesis which is supported by encouraging results in a multitude of pre-clinical animal models. This review provides a clear explanation of the rationale behind the GDEPT principle, outlining the advantages and limitations of different GDEPT strategies with respect to the roles of the bystander effect, the immune system and the selectivity of the activated prodrug in contributing to their therapeutic efficacy. An in-depth analysis of the most widely used suicide gene/prodrug combinations is presented, including details of the latest advances in enzyme and prodrug optimisation and results from the most recent clinical trials.
Assuntos
Genes Transgênicos Suicidas , Terapia Genética , Neoplasias/genética , Neoplasias/terapia , Animais , HumanosRESUMO
BACKGROUND: A novel avian H7N9 virus with a high case fatality rate in humans emerged in China in 2013. We evaluated the immunogenicity and protective efficacy of a candidate Vero cell culture-derived whole-virus H7N9 vaccine in small animal models. METHODS: Antibody responses induced in immunized DBA/2J mice and guinea pigs were evaluated by hemagglutination inhibition (HI), microneutralization (MN), and neuraminidase inhibition (NAi) assays. T-helper cell responses and IgG subclass responses in mice were analyzed by ELISPOT and ELISA, respectively. Vaccine efficacy against lethal challenge with wild-type H7N9 virus was evaluated in immunized mice. H7N9-specific antibody responses induced in mice and guinea pigs were compared to those induced by a licensed whole-virus pandemic H1N1 (H1N1pdm09) vaccine. RESULTS: The whole-virus H7N9 vaccine induced dose-dependent H7N9-specific HI, MN and NAi antibodies in mice and guinea pigs. Evaluation of T-helper cell responses and IgG subclasses indicated the induction of a balanced Th1/Th2 response. Immunized mice were protected against lethal H7N9 challenge in a dose-dependent manner. H7N9 and H1N1pdm09 vaccines were similarly immunogenic. CONCLUSIONS: The induction of H7N9-specific antibody and T cell responses and protection against lethal challenge suggest that the Vero cell culture-derived whole-virus vaccine would provide an effective intervention against the H7N9 virus.
Assuntos
Subtipo H7N9 do Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Animais , Anticorpos Antivirais/imunologia , Formação de Anticorpos , Chlorocebus aethiops , Feminino , Cobaias , Testes de Inibição da Hemaglutinação , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Imunoglobulina G/análise , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/fisiologia , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Interferon gama/análise , Interleucina-4/análise , Camundongos , Camundongos Endogâmicos DBA , Neuraminidase/antagonistas & inibidores , Neuraminidase/metabolismo , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/mortalidade , Células Th1/imunologia , Células Th1/metabolismo , Células Th2/imunologia , Células Th2/metabolismo , Células VeroRESUMO
Ross River virus (RRV) is endemic in Australia and several South Pacific Islands. More than 90,000 cases of RRV disease, which is characterized by debilitating polyarthritis, were reported in Australia in the last 20 years. There is no vaccine available to prevent RRV disease. A phase 3 study was undertaken at 17 sites in Australia to investigate the safety and immunogenicity of an inactivated whole-virus Vero cell culture-derived RRV vaccine in 1,755 healthy younger adults aged 16 to 59 years and 209 healthy older adults aged ≥60 years. Participants received a 2.5-µg dose of Al(OH)(3)-adjuvanted RRV vaccine, with a second and third dose after 3 weeks and 6 months, respectively. Vaccine-induced RRV-specific neutralizing and total IgG antibody titers were measured after each immunization. Vaccine safety was monitored over the entire study period. The vaccine was safe and well-tolerated after each vaccination. No cases of arthritis resembling RRV disease were reported. The most frequently reported systemic reactions were headache, fatigue, and malaise; the most frequently reported injection site reactions were tenderness and pain. After the third immunization, 91.5% of the younger age group and 76.0% of the older age group achieved neutralizing antibody titers of ≥1:10; 89.1% of the younger age group and 70.9% of the older age group achieved enzyme-linked immunosorbent assay (ELISA) titers of ≥11 PanBio units. A whole-virus Vero cell culture-derived RRV vaccine is well tolerated in an adult population and induces antibody titers associated with protection from RRV disease in the majority of individuals. (This study is registered at www.clinicaltrials.gov under registration no. NCT01242670.).
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Infecções por Alphavirus/prevenção & controle , Ross River virus/imunologia , Vacinas de Produtos Inativados/administração & dosagem , Vacinas Virais/administração & dosagem , Adolescente , Adulto , Idoso , Infecções por Alphavirus/epidemiologia , Infecções por Alphavirus/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais , Austrália/epidemiologia , Chlorocebus aethiops , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunização Secundária , Masculino , Pessoa de Meia-Idade , Vacinação , Vacinas de Produtos Inativados/efeitos adversos , Vacinas de Produtos Inativados/imunologia , Células Vero , Vacinas Virais/efeitos adversos , Vacinas Virais/imunologia , Adulto JovemRESUMO
Studies on candidate pandemic vaccines against avian influenza viruses have focused on H5N1, but viruses of other subtypes, such as A/H9N2, are also considered to have pandemic potential. We investigated the safety and immunogenicity of two immunizations with one of five different antigen doses (ranging from 3.75 to 45 µg of hemagglutinin antigen) of a nonadjuvanted whole-virus G9 lineage H9N2 influenza virus vaccine in healthy adults aged 18 to 49 years. The antibody responses were measured by hemagglutination inhibition (HI), microneutralization (MN), and single radial hemolysis (SRH) assays. To investigate a hypothesis that previous exposure to H2N2 viruses in subjects born in or before 1968 might prime for more robust antibody responses to H9N2 vaccination than that in subjects born after 1968, a post hoc age-stratified analysis of antibody responses was done. Both vaccinations in all dose groups were safe and well tolerated. No vaccine-related serious adverse events were reported, and the majority of the adverse reactions were rated as mild. The rates of injection site reactions were lower in the 3.75-µg- and 7.5-µg-dose groups than those in the higher-dose groups; the rates of systemic reactions were similar across all dose groups. The seroprotection rates among the different dose groups 21 days after the second immunization ranged from 52.8% to 88.9% as measured by HI assay, from 88.7% to 98.1% or 82.7% to 96.2% as measured by MN assay (MN titer cutoffs, 1:40 and 1:80, respectively), and from 94.2% to 100% as measured by SRH assay. Higher antibody responses were not induced in subjects born in or before 1968. These data indicate that a nonadjuvanted whole-virus H9N2 vaccine is well tolerated and immunogenic in healthy adults. (This study has been registered at ClinicalTrials.gov under registration no. NCT01320696.).
Assuntos
Vírus da Influenza A Subtipo H9N2/imunologia , Vacinas contra Influenza/efeitos adversos , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Vacinação/efeitos adversos , Vacinação/métodos , Adolescente , Adulto , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Método Duplo-Cego , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/patologia , Feminino , Voluntários Saudáveis , Testes de Inibição da Hemaglutinação , Humanos , Imunodifusão , Vacinas contra Influenza/administração & dosagem , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: The availability of a universal influenza vaccine able to induce broad cross-reactive immune responses against diverse influenza viruses would provide an alternative to currently available strain-specific vaccines. We evaluated the ability of vectors based on modified vaccinia virus Ankara (MVA) expressing conserved influenza proteins to protect mice against lethal challenge with multiple influenza subtypes. METHODS: Mice were immunized with MVA vectors expressing H5N1-derived nucleoprotein (NP), the stem region of hemagglutinin (HA), matrix proteins 1 and 2 (M1 and M2), the viral polymerase basic protein 1 (PB1), or the HA stem fused to a quadrivalent matrix protein 2 extracellular domain (M2e). Immunized mice were challenged with lethal doses of H5N1, H7N1 or H9N2 virus and monitored for disease symptoms and weight loss. To investigate the influence of previous exposure to influenza virus on protective immune responses induced by conserved influenza proteins, mice were infected with pandemic H1N1 virus (H1N1pdm09) prior to immunization and subsequently challenged with H5N1 virus. Antibody and T cell responses were assessed by ELISA and flow cytometry, respectively. RESULTS: MVA vectors expressing NP alone, or co-expressed with other conserved influenza proteins, protected mice against lethal challenge with H5N1, H7N1 or H9N2 virus. Pre-exposure to H1N1pdm09 increased protective efficacy against lethal H5N1 challenge. None of the other conserved influenza proteins provided significant levels of protection against lethal challenge. NP-expressing vectors induced high numbers of influenza-specific CD4(+) and CD8(+) T cells and high titer influenza-specific antibody responses. Higher influenza-specific CD4(+) T cell responses and NP-specific CD8(+) T cell responses were associated with increased protective efficacy. CONCLUSIONS: MVA vectors expressing influenza NP protect mice against lethal challenge with H5N1, H7N1 and H9N2 viruses by a mechanism involving influenza-specific CD4(+) and CD8(+) T cell responses.
Assuntos
Virus da Influenza A Subtipo H5N1/imunologia , Vírus da Influenza A Subtipo H7N1/imunologia , Vírus da Influenza A Subtipo H9N2/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Vaccinia virus/imunologia , Animais , Ensaio de Imunoadsorção Enzimática , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/virologia , Linfócitos T/imunologiaRESUMO
Neuraminidase-inhibiting (NAi) antibodies have been reported to be an independent correlate of protection from influenza disease, but the NAi antibody response to influenza vaccination has never been assessed in chronically ill or immunocompromised participants. Using an enzyme-linked lectin assay, we demonstrated that 2 immunizations with a Vero cell culture-derived, whole-virus H5N1 A/Vietnam vaccine induces NAi antibodies in 94.3% of chronically ill and 83.8% of immunocompromised participants. A booster with a heterologous A/Indonesia H5N1 vaccine induced comparable NAi antibody titers in both groups and resulted in 100% seropositivity. These data support prepandemic H5N1 vaccination strategies for these highly vulnerable risk groups.
RESUMO
The development of vaccines against H5N1 influenza A viruses is a cornerstone of pandemic preparedness. Clinical trials of H5N1 vaccines have been undertaken in healthy subjects, but studies in risk groups have been lacking. In this study, the immunogenicity and safety of a nonadjuvanted cell culture-derived whole-virus H5N1 vaccine were assessed in chronically ill and immunocompromised adults. Subjects received two priming immunizations with a clade 1 A/Vietnam H5N1 influenza vaccine, and a subset also received a booster immunization with a clade 2.1 A/Indonesia H5N1 vaccine 12 to 24 months later. The antibody responses in the two populations were assessed by virus neutralization and single radial hemolysis assays. The T-cell responses in a subset of immunocompromised patients were assessed by enzyme-linked immunosorbent spot assay (ELISPOT). The priming and the booster vaccinations were safe and well tolerated in the two risk populations, and adverse reactions were predominantly mild and transient. The priming immunizations induced neutralizing antibody titers of ≥1:20 against the A/Vietnam strain in 64.2% of the chronically ill and 41.5% of the immunocompromised subjects. After the booster vaccination, neutralizing antibody titers of ≥1:20 against the A/Vietnam and A/Indonesia strains were achieved in 77.5% and 70.8%, respectively, of chronically ill subjects and in 71.6% and 67.5%, respectively, of immunocompromised subjects. The T-cell responses against the two H5N1 strains increased significantly over the baseline values. Substantial heterosubtypic T-cell responses were elicited against the 2009 pandemic H1N1 virus and seasonal A(H1N1), A(H3N2), and B subtypes. There was a significant correlation between T-cell responses and neutralizing antibody titers. These data indicate that nonadjuvanted whole-virus cell culture-derived H5N1 influenza vaccines are suitable for immunizing chronically ill and immunocompromised populations. (This study is registered at ClinicalTrials.gov under registration no. NCT00711295.).
Assuntos
Hospedeiro Imunocomprometido/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/efeitos adversos , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Linhagem Celular , Chlorocebus aethiops , Doença Crônica , Reações Cruzadas/imunologia , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Imunização Secundária , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza B/imunologia , Vacinas contra Influenza/uso terapêutico , Influenza Humana/prevenção & controle , Ativação Linfocitária/imunologia , Masculino , Pessoa de Meia-Idade , Linfócitos T/imunologia , Vacinação , Células VeroRESUMO
Lyme borreliosis (LB) patients who recover, as well as previously infected asymptomatic individuals, remain vulnerable to reinfection with Borrelia burgdorferi sensu lato. There is limited information available about the use of OspA vaccines in this population. In this study, a randomized double-blind phase I/II trial was performed to investigate the safety and immunogenicity of a novel multivalent OspA vaccine in healthy adults who were either seronegative or seropositive for previous B. burgdorferi sensu lato infection. The participants received three monthly priming immunizations with either 30 µg or 60 µg alum-adjuvanted OspA antigen and a booster vaccination either 6 months or 9 to 12 months after the first immunization. The antibody responses to the six OspA serotypes included in the vaccine were evaluated. Adverse events were predominantly mild and transient and were similar in the seronegative and seropositive populations. Substantial enzyme-linked immunosorbent assay (ELISA) and surface-binding antibody responses against all six OspA antigens were induced after the primary immunization schedule in both populations, and they were substantially increased with both booster schedules. The antibody responses induced by the two doses were similar in the seronegative population, but there was a significant dose response in the seropositive population. These data indicate that the novel multivalent OspA vaccine is well tolerated and immunogenic in individuals previously infected with B. burgdorferi sensu lato. (This study is registered at ClinicalTrials.gov under registration no. NCT01504347.).
Assuntos
Antígenos de Superfície/efeitos adversos , Antígenos de Superfície/imunologia , Proteínas da Membrana Bacteriana Externa/efeitos adversos , Proteínas da Membrana Bacteriana Externa/imunologia , Vacinas Bacterianas/efeitos adversos , Vacinas Bacterianas/imunologia , Grupo Borrelia Burgdorferi/imunologia , Lipoproteínas/efeitos adversos , Lipoproteínas/imunologia , Doença de Lyme/imunologia , Doença de Lyme/prevenção & controle , Vacinação/efeitos adversos , Vacinação/métodos , Adjuvantes Imunológicos/administração & dosagem , Adolescente , Adulto , Idoso , Compostos de Alúmen/administração & dosagem , Anticorpos Antibacterianos/sangue , Antígenos de Superfície/administração & dosagem , Proteínas da Membrana Bacteriana Externa/administração & dosagem , Vacinas Bacterianas/administração & dosagem , Método Duplo-Cego , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/patologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Lipoproteínas/administração & dosagem , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Several subtypes of influenza A viruses with pandemic potential are endemic in bird populations throughout Asia, Africa and the Middle East, and evidence suggests that these viruses are adapting to the mammalian host. As emphasized by the high mortality rate of humans infected with H5N1 viruses, this situation presents a substantial risk to global human health. The Vero cell culture platform has been used to develop whole-virus influenza vaccines that provide broad cross-clade protection against viruses with pandemic potential, at low antigen doses, without the requirement for adjuvantation. The safety and immunogenicity of these vaccines has been demonstrated in studies with more than 10,000 individuals, including healthy adult and elderly subjects, children and various risk groups. These Vero cell-derived vaccines are licensed for prepandemic and pandemic use. The Vero platform is also being explored to develop next-generation live-attenuated and recombinant vaccines.
Assuntos
Ensaios Clínicos como Assunto , Descoberta de Drogas/tendências , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Vacinas contra Influenza/isolamento & purificação , Influenza Humana/prevenção & controle , Animais , Técnicas de Cultura de Células/métodos , Humanos , Vírus da Influenza A/genética , Tecnologia Farmacêutica/métodos , Células VeroRESUMO
BACKGROUND: For clinical development of a novel multivalent OspA vaccine against Lyme borreliosis, serological assays are required which can be used to establish immune correlates of protection against infection with Borrelia. METHODS: Four assays (an OspA IgG ELISA, a competitive inhibition (CI) ELISA, a Borrelia surface-binding (SB) assay and a Borrelia killing assay) were used to evaluate the correlation between immune responses induced by rOspA 1/2 (a chimeric immunogen containing protective epitopes from OspA serotypes 1 and 2), and protective immunity against infection by B. burgdorferi s.s. (OspA-1) and B. afzelii (OspA-2). Mice were immunized with OspA 1/2 doses ranging from 0.3 ng to 100 ng, to induce a range of OspA antibody titers, and exposed to needle challenge with B. burgdorferi s.s. or tick challenge with B. afzelii. Receiver operator characteristics (ROC) curves were constructed for each assay, and the area under the curve (AUC), sensitivity, specificity and Youden Index were calculated. Potential cutoff antibody titers which could be used as correlates of vaccine-induced protection were derived from the maximum Youden Index. RESULTS: Immunization with OspA-1/2 provided dose-dependent protection against infection with B. burgdorferi s.s. and B. afzelii. Antibody responses detected by all four assays were highly significantly correlated with protection from infection by either B. burgdorferi s.s. (p<0.0001 to 0.0062) or B. afzelii (p<0.0001). ROC analyses of the diagnostic effectiveness of each assay showed the AUC to range between 0.95 and 0.79, demonstrating that all assays distinguish well between infected and non-infected animals. Based on sensitivity, specificity and AUC, the OspA IgG ELISA and SB assays best discriminated between infected and non-infected animals. CONCLUSIONS: All four assays differentiate well between Borrelia-infected and non-infected animals. The relatively simple, high throughput IgG ELISA would be suitable to establish immune correlates of protection for the novel OspA vaccine in clinical trials.
Assuntos
Antígenos de Superfície/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Vacinas Bacterianas/imunologia , Borrelia burgdorferi/imunologia , Lipoproteínas/imunologia , Vacinas contra Doença de Lyme/imunologia , Doença de Lyme/prevenção & controle , Animais , Anticorpos Antibacterianos/imunologia , Modelos Animais de Doenças , Relação Dose-Resposta Imunológica , Feminino , Imunoglobulina G/imunologia , Doença de Lyme/imunologia , Camundongos , VacinaçãoRESUMO
BACKGROUND: Lyme borreliosis is caused by Borrelia burgdorferi sensu stricto in the USA and by several Borrelia species in Europe and Asia, but no human vaccine is available. We investigated the safety and immunogenicity of adjuvanted and non-adjuvanted vaccines containing protective epitopes from Borrelia species outer surface protein A (OspA) serotypes in healthy adults. METHODS: Between March 1, 2011, and May 8, 2012, we did a double-blind, randomised, dose-escalation phase 1/2 study at four sites in Austria and Germany. Healthy adults aged 18-70 years who were seronegative for B. burgdorferi sensu lato were eligible for inclusion. Participants were recruited sequentially and randomly assigned to one of six study groups in equal ratios via an electronic data capture system. Participants and investigators were masked to group allocation. Participants received three vaccinations containing 30 µg, 60 µg, or 90 µg OspA antigen with or without an adjuvant, with intervals of 28 days, and a booster 9-12 months after the first immunisation. The coprimary endpoints were the frequency and severity of injection-site and systemic reactions within 7 days of each vaccination, and the antibody responses to OspA serotypes 1-6, as established by ELISA. This study is registered with ClinicalTrials.gov, number NCT01504347. FINDINGS: 300 participants were randomly assigned: 151 to adjuvanted vaccines (50 to 30 µg, 51 to 60 µg, and 50 to 90 µg doses), and 149 to non-adjuvanted vaccines (50 to 30 µg, 49 to 60 µg, and 50 to 90 µg doses). Adverse reactions were predominantly mild, and no vaccine-related serious adverse events were reported. The risk of systemic reactions (risk ratio 0·54 [95% CI 0·41-0·70]; p<0·0001) and of moderate or severe systemic reactions (0·35 [0·13-0·92]; p=0·034) was significantly lower for adjuvanted than non-adjuvanted formulations. The 30 µg adjuvanted formulation had the best tolerability profile; only headache (five [10%, 95% CI 4-20] of 50), injection-site pain (16 [32%, 21-45]), and tenderness (17 [34%, 23-47]) affected more than 6% of patients. All doses and formulations induced substantial mean IgG antibody titres against OspA serotypes 1-6 after the first three vaccinations (range 6944-17,321) and booster (19,056-32,824) immunisations. The 30 µg adjuvanted formulation induced the highest antibody titres after the booster: range 26,143 (95% CI 18,906-36,151) to 42,381 (31,288-57,407). INTERPRETATION: The novel multivalent OspA vaccine could be an effective intervention for prevention of Lyme borreliosis in Europe and the USA, and possibly worldwide. Larger confirmatory formulation studies will need to be done that include individuals seropositive for Borrelia burgdorferi sensu lato before placebo-controlled phase 3 efficacy studies can begin. FUNDING: Baxter.
Assuntos
Adjuvantes Imunológicos/efeitos adversos , Antígenos de Superfície/efeitos adversos , Antígenos de Superfície/imunologia , Proteínas da Membrana Bacteriana Externa/efeitos adversos , Proteínas da Membrana Bacteriana Externa/imunologia , Vacinas Bacterianas/efeitos adversos , Vacinas Bacterianas/imunologia , Borrelia burgdorferi/imunologia , Lipoproteínas/efeitos adversos , Lipoproteínas/imunologia , Vacinas contra Doença de Lyme/efeitos adversos , Vacinas contra Doença de Lyme/imunologia , Adulto , Método Duplo-Cego , Feminino , Cefaleia/induzido quimicamente , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Dor/induzido quimicamente , Adulto JovemRESUMO
BACKGROUND: Preparation for an H5N1 influenza pandemic in humans could include priming the population in the pre-pandemic period with a vaccine produced from an existing H5N1 vaccine strain, with the possibility of boosting with a pandemic virus vaccine when it becomes available. We investigated the longevity of the immune response after one or two priming immunizations with a whole-virus H5N1 vaccine and the extent to which this can be boosted by later immunization with either a homologous or heterologous vaccine. METHODS: Mice received one or two priming immunizations with a Vero cell culture-derived, whole-virus clade 1 H5N1 vaccine formulated to contain either 750 ng or 30 ng hemagglutinin. Six months after the first priming immunization, mice received either a booster immunization with the same clade 1 vaccine or a heterologous clade 2.1 vaccine, or buffer. Humoral and cellular immune responses were evaluated before and at regular intervals after immunizations. Three weeks after booster immunization, mice were challenged with a lethal dose of wild-type H5N1 virus from clades 1, 2.1 or 2.2 and survival was monitored for 14 days. RESULTS: One or two priming immunizations with the 750 ng or 30 ng HA formulations, respectively, induced H5N1-neutralizing antibody titers which were maintained for ≥ 6 months and provided long-term cross-clade protection against wild-type virus challenge. Both humoral and cellular immune responses were substantially increased by a booster immunization after 6 months. The broadest protective immunity was provided by an immunization regimen consisting of one or two priming immunizations with a clade 1 vaccine and a boosting immunization with a clade 2.1 vaccine. CONCLUSIONS: These data support the concept that pre-pandemic vaccination can provide robust and long-lasting H5N1 immunity which could be effectively boosted by immunization either with another pre-pandemic vaccine or with the pandemic strain vaccine.
Assuntos
Imunização Secundária , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Animais , Anticorpos Heterófilos , Anticorpos Neutralizantes , Chlorocebus aethiops , Reações Cruzadas/imunologia , Relação Dose-Resposta Imunológica , Feminino , Imunidade Celular/imunologia , Imunidade Humoral , Esquemas de Imunização , Virus da Influenza A Subtipo H5N1/patogenicidade , Camundongos , Células Vero/virologiaRESUMO
BACKGROUND: Cell culture technologies have the potential to improve the robustness and flexibility of influenza vaccine supply and to substantially shorten manufacturing timelines. We investigated the safety, immunogenicity and efficacy of a Vero cell culture-derived seasonal influenza vaccine and utilized these studies to establish a serological correlate of vaccine protection. METHODS: Two multicenter, randomized, double-blind phase III trials were undertaken in the US during the 2008-2009 Northern hemisphere influenza season, in young (18-49 years) and older (50-64 years and ≥ 65 years) adult subjects. 7250 young adults were randomized 1:1 to receive either Vero-derived vaccine or placebo. 3210 older adult subjects were randomized 8:1 to receive either Vero-derived vaccine or a licensed egg-derived vaccine. Serum hemagglutination inhibition antibody titers were assessed 21 days post-vaccination. Vaccine efficacy in preventing cell culture-confirmed influenza infection was determined for the young adult population. Local and systemic adverse events were recorded in both studies. RESULTS: The Vero-derived vaccine was safe and well tolerated in both young and older adults. All US and European immunological licensing thresholds were comfortably met in both populations. Vaccine efficacy in young adults was 79% against A/H1N1 viruses antigenically matching the corresponding vaccine strain and 78.5% for all antigenically matched influenza viruses. A hemagglutination inhibition antibody titer of ≥ 1:15 provided a reliable correlate of protection for the Vero-derived influenza vaccine, with no additional benefit at titers >1:30. Bridging of the correlate of protection established in the young adult population to the older adult immunogenicity data demonstrated the likely effectiveness of the Vero-derived vaccine in the older adult population. CONCLUSIONS: A Vero cell culture-derived seasonal influenza vaccine is safe, immunogenic and protects against infection with influenza virus. The novel vaccine technology has the potential to make a substantial contribution to improving influenza vaccine supply. CLINICAL TRIAL REGISTRATION: The studies are registered with ClinicalTrials.gov, numbers NCT00566345 and NCT00782431.
Assuntos
Vacinas contra Influenza/biossíntese , Influenza Humana/prevenção & controle , Adolescente , Adulto , Idoso , Animais , Anticorpos Antivirais/sangue , Técnicas de Cultura de Células , Chlorocebus aethiops , Método Duplo-Cego , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/efeitos adversos , Masculino , Pessoa de Meia-Idade , Células Vero , Adulto JovemRESUMO
BACKGROUND: Influenza viruses of subtype A/H9N2 are enzootic in poultry across Asia and the Middle East and are considered to have pandemic potential. The development of new vaccine manufacturing technologies is a cornerstone of influenza pandemic preparedness. METHODS: A non-adjuvanted whole-virus H9N2 vaccine was developed using Vero cell culture manufacturing technology. The induction of hemagglutination inhibition (HI) and virus-neutralizing antibodies was assessed in CD1 mice and guinea pigs. A highly sensitive enzyme-linked lectin assay was used to investigate the induction of antibodies capable of inhibiting the enzymatic activity of the H9N2 neuraminidase. Protective efficacy against virus replication in the lung after challenge with the homologous virus was evaluated in BALB/c mice by a TCID(50) assay, and prevention of virus replication in the lung and associated pathology were evaluated by histology and immunohistochemistry. To investigate the ability of the vaccine to prevent severe disease, BALB/c mice were challenged with a highly virulent mouse-adapted H9N2 isolate which was generated by multiple lung-to-lung passage of wild-type virus. RESULTS: The vaccine elicited high titers of functional H9N2-specific HA antibodies in both mice and guinea pigs, as determined by HI and virus neutralization assays. High titer H9N2-specific neuraminidase inhibiting (NAi) antibodies were also induced in both species. Vaccinated mice were protected from lung virus replication in a dose-dependent manner after challenge with the homologous H9N2 virus. Immunohistochemical analyses confirmed the lack of virus replication in the lung and an associated substantial reduction in lung pathology. Dose-dependent protection from severe weight loss was also provided after challenge with the highly virulent mouse-adapted H9N2 virus. CONCLUSIONS: The induction of high titers of H9N2-specific HI, virus-neutralizing and NAi antibodies and dose-dependent protection from virus replication and severe disease in animal models suggest that the Vero cell culture-derived whole-virus vaccine will provide an effective intervention in the event of a H9N2 pandemic situation.