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1.
Nat Immunol ; 20(10): 1291-1298, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31477918

RESUMO

Infections with dengue virus (DENV) and Zika virus (ZIKV) can induce cross-reactive antibody responses. Two immunodominant epitopes-one to precursor membrane protein and one to the fusion loop epitope on envelope (E) protein-are recognized by cross-reactive antibodies1-3 that are not only poorly neutralizing, but can also promote increased viral replication and disease severity via Fcγ receptor-mediated infection of myeloid cells-a process termed antibody-dependent enhancement (ADE)1,4,5. ADE is a significant concern for both ZIKV and DENV vaccines as the induction of poorly neutralizing cross-reactive antibodies may prime an individual for ADE on natural infection. In this report, we describe the design and production of covalently stabilized ZIKV E dimers, which lack precursor membrane protein and do not expose the immunodominant fusion loop epitope. Immunization of mice with ZIKV E dimers induces dimer-specific antibodies, which protect against ZIKV challenge during pregnancy. Importantly, the ZIKV E-dimer-induced response does not cross-react with DENV or induce ADE of DENV infection.


Assuntos
Vírus da Dengue/fisiologia , Dengue/imunologia , Vacinas Virais/imunologia , Infecção por Zika virus/imunologia , Zika virus/fisiologia , Animais , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Reações Cruzadas , Dimerização , Epitopos/genética , Feminino , Engenharia Genética , Células HEK293 , Humanos , Epitopos Imunodominantes/genética , Camundongos , Camundongos Endogâmicos BALB C , Receptores de IgG/metabolismo , Vacinação , Proteínas do Envelope Viral/genética , Vacinas Virais/genética , Replicação Viral
2.
J Immunol ; 207(11): 2631-2635, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34716185

RESUMO

Radiation-attenuated sporozoite (RAS) vaccination offers hope for global malaria control through induction of protective liver-stage-specific memory CD8 T cells. Effective RAS vaccination regimens exist; however, widespread implementation remains unfeasible. A key difficulty resides in the need to administer three or more doses i.v. to achieve sufficient immunity. Strategies to reduce the number of RAS doses are therefore desirable. Here we used mice to model human immune responses to a single, suboptimal weight-normalized RAS dose administered i.v. followed by subunit vaccination to amplify liver-stage-specific memory CD8 T cells. RAS+subunit prime-boost regimens increased the numbers of liver-stage-specific memory CD8 T cells to a level greater than is present after one RAS vaccination. Both i.v. and i.m. subunit vaccine delivery induced immunity in mice, and many vaccinated mice completely cleared liver infection. These findings are particularly relevant to human vaccine development because RAS+subunit prime-boost vaccination would reduce the logistical challenges of multiple RAS-only immunizations.


Assuntos
Hepatopatias/imunologia , Vacinas Antimaláricas/imunologia , Malária/imunologia , Esporozoítos/imunologia , Vacinas Atenuadas/imunologia , Vacinas de Subunidades Antigênicas/imunologia , Animais , Imunização , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Vacinação
3.
Int J Mol Sci ; 23(8)2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35456923

RESUMO

Mayaro virus (MAYV) is an emerging alphavirus causing acute febrile illness associated with chronic polyarthralgia. Although MAYV is currently restricted to tropical regions in South America around the Amazon basin, it has the potential to spread globally by Aedes species mosquitoes. In addition, there are currently no specific therapeutics or licenced vaccines against MAYV infection. We have previously shown that an adenovirus based Mayaro vaccine (ChAdOx1 May) was able to provide full protection against MAYV challenge in vaccinated A129 mice and induced high neutralising antibody titres. In this study, we have constructed a replication deficient simian adenovirus (ChAdOx2) and a Modified Ankara Virus (MVA) based vaccine expressing the MAYV structural cassette (sMAYV) similar to ChAdOx1 May, and characterised recombinant MAYV E2 glycoprotein expressed in a mammalian system for immune monitoring. We demonstrate that ChAdOx2 May was able to induce high antibody titres similar to ChAdOx1 May, and MVA May was shown to be an effective boosting strategy following prime vaccination with ChAdOx1 or ChAdOx2 May. In order to measure MAYV neutralising ability, we have developed a virus replicon particle-based neutralisation assay which effectively detected neutralising antibodies against MAYV. In summary, our study indicates the potential for further clinical development of the viral vectored MAYV vaccines against MAYV infections.


Assuntos
Infecções por Alphavirus , Vírus Chikungunya , Vacinas Virais , Infecções por Alphavirus/prevenção & controle , Animais , Anticorpos Antivirais , Mamíferos , Camundongos , Replicon , Vacinas Virais/genética
4.
J Med Virol ; 93(4): 2029-2038, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-32986250

RESUMO

SARS-CoV-2 infection is causing a pandemic disease that is reflected in challenging public health problems worldwide. Human leukocyte antigen (HLA)-based epitope prediction and its association with disease outcomes provide an important base for treatment design. A bioinformatic prediction of T cell epitopes and their restricted HLA Class I and II alleles was performed to obtain immunogenic epitopes and HLA alleles from the spike protein of the severe acute respiratory syndrome coronavirus 2 virus. Also, a correlation with the predicted fatality rate of hospitalized patients in 28 states of Mexico was done. Here, we describe a set of 10 highly immunogenic epitopes, together with different HLA alleles that can efficiently present these epitopes to T cells. Most of these epitopes are located within the S1 subunit of the spike protein, suggesting that this area is highly immunogenic. A statistical negative correlation was found between the frequency of HLA-DRB1*01 and the fatality rate in hospitalized patients in Mexico.


Assuntos
Apresentação de Antígeno , COVID-19 , Cadeias HLA-DRB1/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , COVID-19/imunologia , COVID-19/mortalidade , Biologia Computacional , Epitopos de Linfócito T/imunologia , Variação Genética , Hospitalização , Humanos , México , Estrutura Terciária de Proteína , SARS-CoV-2/imunologia
5.
Infect Immun ; 88(10)2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32719159

RESUMO

The circumsporozoite protein (CSP) builds up the surface coat of sporozoites and is the leading malaria pre-erythrocytic-stage vaccine candidate. CSP has been shown to induce robust CD8+ T cell responses that are capable of eliminating developing parasites in hepatocytes, resulting in protective immunity. In this study, we characterized the importance of the immunodominant CSP-derived epitope SYIPSAEKI of Plasmodium berghei in both sporozoite- and vaccine-induced protection in murine infection models. In BALB/c mice, where SYIPSAEKI is efficiently presented in the context of the major histocompatibility complex class I (MHC-I) molecule H-2-Kd, we established that epitope-specific CD8+ T cell responses contribute to parasite killing following sporozoite immunization. Yet, sterile protection was achieved in the absence of this epitope, substantiating the concept that other antigens can be sufficient for parasite-induced protective immunity. Furthermore, we demonstrated that SYIPSAEKI-specific CD8+ T cell responses elicited by viral-vectored CSP-expressing vaccines effectively targeted parasites in hepatocytes. The resulting sterile protection strictly relied on the expression of SYIPSAEKI. In C57BL/6 mice, which are unable to present the immunodominant epitope, CSP-based vaccines did not confer complete protection, despite the induction of high levels of CSP-specific antibodies. These findings underscore the significance of CSP in protection against malaria pre-erythrocytic stages and demonstrate that a significant proportion of the protection against the parasite is mediated by CD8+ T cells specific for the immunodominant CSP-derived epitope.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Epitopos de Linfócito T/imunologia , Vacinas Antimaláricas/imunologia , Malária/prevenção & controle , Plasmodium berghei/imunologia , Proteínas de Protozoários/imunologia , Animais , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Apresentação de Antígeno , Antígenos de Protozoários/genética , Antígenos de Protozoários/imunologia , Modelos Animais de Doenças , Epitopos de Linfócito T/química , Imunização , Malária/imunologia , Malária/parasitologia , Vacinas Antimaláricas/administração & dosagem , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Fragmentos de Peptídeos , Proteínas de Protozoários/química , Especificidade da Espécie , Esporozoítos/imunologia
6.
Infect Immun ; 86(9)2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29986894

RESUMO

Vivax malaria remains one of the most serious and neglected tropical diseases, with 132 to 391 million clinical cases per year and 2.5 billion people at risk of infection. A vaccine against Plasmodium vivax could have more impact than any other intervention, and the use of a vaccine targeting multiple antigens may result in higher efficacy against sporozoite infection than targeting a single antigen. Here, two leading P. vivax preerythrocytic vaccine candidate antigens, the P. vivax circumsporozoite protein (PvCSP) and the thrombospondin-related adhesion protein (PvTRAP) were delivered as a combined vaccine. This strategy provided a dose-sparing effect, with 100% sterile protection in mice using doses that individually conferred low or no protection, as with the unadjuvanted antigens PvTRAP (0%) and PvCSP (50%), and reached protection similar to that of adjuvanted components. Efficacy against malaria infection was assessed using a new mouse challenge model consisting of a double-transgenic Plasmodium berghei parasite simultaneously expressing PvCSP and PvTRAP used in mice immunized with the virus-like particle (VLP) Rv21 previously reported to induce high efficacy in mice using Matrix-M adjuvant, while PvTRAP was concomitantly administered in chimpanzee adenovirus and modified vaccinia virus Ankara (MVA) vectors (viral-vectored TRAP, or vvTRAP) to support effective induction of T cells. We examined immunity elicited by these vaccines in the context of two adjuvants approved for human use (AddaVax and Matrix-M). Matrix-M supported the highest anti-PvCSP antibody titers when combined with Rv21, and, interestingly, mixing PvCSP Rv21 and PvTRAP viral vectors enhanced immunity to malaria over levels provided by single vaccines.


Assuntos
Vacinas Antimaláricas/imunologia , Malária Vivax/prevenção & controle , Plasmodium vivax/imunologia , Proteínas de Protozoários/imunologia , Adenoviridae/genética , Adjuvantes Imunológicos , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Feminino , Vetores Genéticos , Malária Vivax/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas/administração & dosagem , Plasmodium berghei/genética , Plasmodium berghei/imunologia , Polissorbatos/administração & dosagem , Proteínas de Protozoários/administração & dosagem , Saponinas/administração & dosagem , Esqualeno/administração & dosagem , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Vacinas de Partículas Semelhantes a Vírus/genética , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vaccinia virus/genética
7.
Virol J ; 15(1): 193, 2018 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-30587198

RESUMO

BACKGROUND: Zika virus (ZIKV) has become a global threat with immediate need for accurate diagnostics, efficacious vaccines and therapeutics. Several ZIKV envelope (Env)-based vaccines have been developed recently. However, many commercially available ZIKV Env are based on the African lineage and produced in insect cells. Here, we sought to produce Asian-lineage ZIKV Env in mammalian cells for research and clinical applications. METHODS: We designed various gene expression constructs to optimize the production of ZIKV using prM-Env and full or C-terminal truncations of Env; with or without a rat CD4 fusion partner to allow large-scale production of soluble protein in mammalian HEK293 cells. Protein expression was verified by mass spectrometry and western-blot with a pan-flavivirus antibody, a ZIKV Env monoclonal antibody and with immune sera from adenoviral (ChAdOx1) ZIKV Env-vaccinated mice. The resulting Env-CD4 was used as a coating reagent for immunoassay (ELISA) using both mouse and human seropositive sera. RESULTS: Replacement of the C-terminus transmembrane Env domain by a rat CD4 and addition of prM supported optimal expression and secretion of Env. Binding between the antigens and the antibodies was similar to binding when using commercially available ZIKV Env reagents. Furthermore, antibodies from ZIKV patients bound ZIKV Env-CD4 in ELISA assays, whereas sera from healthy blood donors yielded minimal OD background. The serological outcomes of this assay correlated also with ZIKV neutralisation capacity in vitro. CONCLUSIONS: Results obtained from this study indicate the potential of the Asian-lineage Zika Env-CD4 and Env proteins in ELISA assays to monitor humoral immune responses in upcoming clinical trials as well as a sero-diagnostic tool in ZIKV infection.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Proteínas Recombinantes de Fusão/imunologia , Proteínas do Envelope Viral/imunologia , Proteínas do Envelope Viral/isolamento & purificação , Zika virus/imunologia , Animais , Antígenos CD4/genética , Ensaio de Imunoadsorção Enzimática/métodos , Células HEK293 , Humanos , México , Camundongos , Testes de Neutralização/métodos , Ratos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Zika virus/genética
8.
Malar J ; 17(1): 288, 2018 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-30092798

RESUMO

BACKGROUND: Rodent malaria parasites where the gene encoding circumsporozoite protein (CSP) has been replaced with csp genes from the human malaria parasites, Plasmodium falciparum or Plasmodium vivax, are used as pre-clinical tools to evaluate CSP vaccines in vivo. These chimeric rodent parasites produce sporozoites in Anopheles stephensi mosquitoes that are capable of infecting rodent and human hepatocytes. The availability of chimeric P. falciparum parasites where the pfcsp gene has been replaced by the pvcsp would open up possibilities to test P. vivax CSP vaccines in small scale clinical trials using controlled human malaria infection studies. METHODS: Using CRISPR/Cas9 gene editing two chimeric P. falciparum parasites, were generated, where the pfcsp gene has been replaced by either one of the two major pvcsp alleles, VK210 or VK247. In addition, a P. falciparum parasite line that lacks CSP expression was also generated. These parasite lines have been analysed for sporozoite production in An. stephensi mosquitoes. RESULTS: The two chimeric Pf-PvCSP lines exhibit normal asexual and sexual blood stage development in vitro and produce sporozoite-containing oocysts in An. stephensi mosquitoes. Expression of the corresponding PvCSP was confirmed in oocyst-derived Pf-PvCSP sporozoites. However, most oocysts degenerate before sporozoite formation and sporozoites were not found in either the mosquito haemocoel or salivary glands. Unlike the chimeric Pf-PvCSP parasites, oocysts of P. falciparum parasites lacking CSP expression do not produce sporozoites. CONCLUSIONS: Chimeric P. falciparum parasites expressing P. vivax circumsporozoite protein fail to produce salivary gland sporozoites. Combined, these studies show that while PvCSP can partially complement the function of PfCSP, species-specific features of CSP govern full sporozoite maturation and development in the two human malaria parasites.


Assuntos
Anopheles/parasitologia , Quimera/genética , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Esporozoítos/fisiologia , Animais , Expressão Gênica , Plasmodium vivax/genética , Proteínas de Protozoários/metabolismo , Glândulas Salivares/parasitologia
9.
Infect Immun ; 84(3): 622-34, 2015 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-26667840

RESUMO

The leading malaria vaccine candidate, RTS,S, based on the Plasmodium falciparum circumsporozoite protein (CSP), will likely be the first publicly adopted malaria vaccine. However, this and other subunit vaccines, such as virus-vectored thrombospondin-related adhesive protein (TRAP), provide only intermediate to low levels of protection. In this study, the Plasmodium berghei homologues of antigens CSP and TRAP are combined. TRAP is delivered using adenovirus- and vaccinia virus-based vectors in a prime-boost regime. Initially, CSP is also delivered using these viral vectors; however, a reduction of anti-CSP antibodies is seen when combined with virus-vectored TRAP, and the combination is no more protective than either subunit vaccine alone. Using an adenovirus-CSP prime, protein-CSP boost regime, however, increases anti-CSP antibody titers by an order of magnitude, which is maintained when combined with virus-vectored TRAP. This combination regime using protein CSP provided 100% protection in C57BL/6 mice compared to no protection using virus-vectored TRAP alone and 40% protection using adenovirus-CSP prime and protein-CSP boost alone. This suggests that a combination of CSP and TRAP subunit vaccines could enhance protection against malaria.


Assuntos
Eritrócitos/parasitologia , Vacinas Antimaláricas/imunologia , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Eritrócitos/imunologia , Feminino , Vetores Genéticos/genética , Vetores Genéticos/metabolismo , Humanos , Vacinas Antimaláricas/genética , Malária Falciparum/parasitologia , Malária Falciparum/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Vaccinia virus/genética , Vaccinia virus/metabolismo
10.
Infect Immun ; 82(3): 1277-86, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24379295

RESUMO

Plasmodium vivax is the world's most widely distributed malaria parasite and a potential cause of morbidity and mortality for approximately 2.85 billion people living mainly in Southeast Asia and Latin America. Despite this dramatic burden, very few vaccines have been assessed in humans. The clinically relevant vectors modified vaccinia virus Ankara (MVA) and the chimpanzee adenovirus ChAd63 are promising delivery systems for malaria vaccines due to their safety profiles and proven ability to induce protective immune responses against Plasmodium falciparum thrombospondin-related anonymous protein (TRAP) in clinical trials. Here, we describe the development of new recombinant ChAd63 and MVA vectors expressing P. vivax TRAP (PvTRAP) and show their ability to induce high antibody titers and T cell responses in mice. In addition, we report a novel way of assessing the efficacy of new candidate vaccines against P. vivax using a fully infectious transgenic Plasmodium berghei parasite expressing P. vivax TRAP to allow studies of vaccine efficacy and protective mechanisms in rodents. Using this model, we found that both CD8+ T cells and antibodies mediated protection against malaria using virus-vectored vaccines. Our data indicate that ChAd63 and MVA expressing PvTRAP are good preerythrocytic-stage vaccine candidates with potential for future clinical application.


Assuntos
Adenoviridae/imunologia , Vacinas Antimaláricas/imunologia , Malária Vivax/imunologia , Plasmodium berghei/imunologia , Plasmodium vivax/imunologia , Proteínas de Protozoários/genética , Vaccinia virus/imunologia , Adenoviridae/genética , Animais , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/genética , Antígenos de Protozoários/imunologia , Linfócitos T CD8-Positivos/imunologia , Culicidae/imunologia , Feminino , Vetores Genéticos/genética , Vetores Genéticos/imunologia , Vacinas Antimaláricas/genética , Malária Vivax/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Pan troglodytes/imunologia , Pan troglodytes/virologia , Plasmodium berghei/genética , Proteínas de Protozoários/imunologia , Vacínia/genética , Vacínia/imunologia , Vaccinia virus/genética
11.
Viruses ; 16(6)2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38932175
12.
J Virol ; 86(8): 4082-90, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22318135

RESUMO

Vaccination using "naked" DNA is a highly attractive strategy for induction of pathogen-specific immune responses; however, it has been only weakly immunogenic in humans. Previously, we constructed DNA-launched Semliki Forest virus replicons (DREP), which stimulate pattern recognition receptors and induce augmented immune responses. Also, in vivo electroporation was shown to enhance immune responses induced by conventional DNA vaccines. Here, we combine these two approaches and show that in vivo electroporation increases CD8(+) T cell responses induced by DREP and consequently decreases the DNA dose required to induce a response. The vaccines used in this study encode the multiclade HIV-1 T cell immunogen HIVconsv, which is currently being evaluated in clinical trials. Using intradermal delivery followed by electroporation, the DREP.HIVconsv DNA dose could be reduced to as low as 3.2 ng to elicit frequencies of HIV-1-specific CD8(+) T cells comparable to those induced by 1 µg of a conventional pTH.HIVconsv DNA vaccine, representing a 625-fold molar reduction in dose. Responses induced by both DREP.HIVconsv and pTH.HIVconsv were further increased by heterologous vaccine boosts employing modified vaccinia virus Ankara MVA.HIVconsv and attenuated chimpanzee adenovirus ChAdV63.HIVconsv. Using the same HIVconsv vaccines, the mouse observations were supported by an at least 20-fold-lower dose of DNA vaccine in rhesus macaques. These data point toward a strategy for overcoming the low immunogenicity of DNA vaccines in humans and strongly support further development of the DREP vaccine platform for clinical evaluation.


Assuntos
DNA Viral/imunologia , HIV-1/imunologia , Plasmídeos/imunologia , Vírus da Floresta de Semliki/genética , Vírus da Floresta de Semliki/imunologia , Linfócitos T/imunologia , Vacinas de DNA/imunologia , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/genética , Vacinas contra a AIDS/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Linhagem Celular , DNA Viral/genética , Eletroporação , Feminino , Ordem dos Genes , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Humanos , Macaca mulatta , Camundongos , Camundongos Endogâmicos BALB C , Plasmídeos/administração & dosagem , Plasmídeos/genética , Vacinas de DNA/administração & dosagem , Vacinas de DNA/genética
13.
Virol J ; 10: 349, 2013 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-24304565

RESUMO

BACKGROUND: Rift Valley Fever (RVF) is a viral zoonosis that historically affects livestock production and human health in sub-Saharan Africa, though epizootics have also occurred in the Arabian Peninsula. Whilst an effective live-attenuated vaccine is available for livestock, there is currently no licensed human RVF vaccine. Replication-deficient chimpanzee adenovirus (ChAd) vectors are an ideal platform for development of a human RVF vaccine, given the low prevalence of neutralizing antibodies against them in the human population, and their excellent safety and immunogenicity profile in human clinical trials of vaccines against a wide range of pathogens. METHODS: Here, in BALB/c mice, we evaluated the immunogenicity and efficacy of a replication-deficient chimpanzee adenovirus vector, ChAdOx1, encoding the RVF virus envelope glycoproteins, Gn and Gc, which are targets of virus neutralizing antibodies. The ChAdOx1-GnGc vaccine was assessed in comparison to a replication-deficient human adenovirus type 5 vector encoding Gn and Gc (HAdV5-GnGc), a strategy previously shown to confer protective immunity against RVF in mice. RESULTS: A single immunization with either of the vaccines conferred protection against RVF virus challenge eight weeks post-immunization. Both vaccines elicited RVF virus neutralizing antibody and a robust CD8+ T cell response. CONCLUSIONS: Together the results support further development of RVF vaccines based on replication-deficient adenovirus vectors, with ChAdOx1-GnGc being a potential candidate for use in future human clinical trials.


Assuntos
Adenoviridae/genética , Portadores de Fármacos , Vetores Genéticos , Febre do Vale de Rift/prevenção & controle , Vírus da Febre do Vale do Rift/imunologia , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Linfócitos T CD8-Positivos/imunologia , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Febre do Vale de Rift/imunologia , Vírus da Febre do Vale do Rift/genética , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/genética , Vacinas Atenuadas/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Vacinas Virais/administração & dosagem , Vacinas Virais/genética
14.
J Immunol ; 187(3): 1347-57, 2011 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-21715686

RESUMO

Identification of correlates of protection for infectious diseases including malaria is a major challenge and has become one of the main obstacles in developing effective vaccines. We investigated protection against liver-stage malaria conferred by vaccination with adenoviral (Ad) and modified vaccinia Ankara (MVA) vectors expressing pre-erythrocytic malaria Ags. By classifying CD8(+) T cells into effector, effector memory (T(EM)), and central memory subsets using CD62L and CD127 markers, we found striking differences in T cell memory generation. Although MVA induced accelerated central memory T cell generation, which could be efficiently boosted by subsequent Ad administration, it failed to protect against malaria. In contrast, Ad vectors, which permit persistent Ag delivery, elicit a prolonged effector T cell and T(EM) response that requires long intervals for an efficient boost. A preferential T(EM) phenotype was maintained in liver, blood, and spleen after Ad/MVA prime-boost regimens, and animals were protected against malaria sporozoite challenge. Blood CD8(+) T(EM) cells correlated with protection against malaria liver-stage infection, assessed by estimation of number of parasites emerging from the liver into the blood. The protective ability of Ag-specific T(EM) cells was confirmed by transfer experiments into naive recipient mice. Thus, we identify persistent CD8 T(EM) populations as essential for vaccine-induced pre-erythrocytic protection against malaria, a finding that has important implications for vaccine design.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/parasitologia , Memória Imunológica , Hepatopatias Parasitárias/imunologia , Hepatopatias Parasitárias/prevenção & controle , Malária/imunologia , Malária/prevenção & controle , Adenoviridae/genética , Adenoviridae/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Epitopos de Linfócito T/administração & dosagem , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Feminino , Vetores Genéticos/administração & dosagem , Vetores Genéticos/imunologia , Vetores Genéticos/uso terapêutico , Antígenos H-2/administração & dosagem , Antígenos H-2/genética , Antígenos H-2/imunologia , Humanos , Memória Imunológica/genética , Hepatopatias Parasitárias/patologia , Malária/patologia , Vacinas Antimaláricas/administração & dosagem , Vacinas Antimaláricas/genética , Vacinas Antimaláricas/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Plasmodium berghei/genética , Plasmodium berghei/imunologia , Proteínas de Protozoários/administração & dosagem , Proteínas de Protozoários/genética , Proteínas de Protozoários/imunologia , Transgenes/imunologia , Vacínia/genética , Vacínia/imunologia
15.
Mol Ther ; 20(8): 1633-47, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22354374

RESUMO

Substantial protection can be provided against the pre-erythrocytic stages of malaria by vaccination first with an adenoviral and then with an modified vaccinia virus Ankara (MVA) poxviral vector encoding the same ME.TRAP transgene. We investigated whether the two vaccine components adenovirus (Ad) and MVA could be coinjected as a mixture to enhance protection against malaria. A single-shot mixture at specific ratios of Ad and MVA (Ad+MVA) enhanced CD8(+) T cell-dependant protection of mice against challenge with Plasmodium berghei. Moreover, the degree of protection could be enhanced after homologous boosting with the same Ad+MVA mixture to levels comparable with classic heterologous Ad prime-MVA boost regimes. The mixture increased transgene-specific responses while decreasing the CD8(+) T cell antivector immunity compared to each vector used alone, particularly against the MVA backbone. Mixed vector immunization led to increased early circulating interferon-γ (IFN-γ) response levels and altered transcriptional microarray profiles. Furthermore, we found that sequential immunizations with the Ad+MVA mixture led to consistent boosting of the transgene-specific CD8(+) response for up to three mixture immunizations, whereas each vector used alone elicited progressively lower responses. Our findings offer the possibility of simplifying the deployment of viral vectors as a single mixture product rather than in heterologous prime-boost regimens.


Assuntos
Adenoviridae/imunologia , Imunização/métodos , Vaccinia virus/imunologia , Adenoviridae/genética , Animais , Linfócitos T CD8-Positivos/imunologia , Feminino , Vetores Genéticos/genética , Malária/imunologia , Malária/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C , Plasmodium berghei/imunologia , Vaccinia virus/genética
16.
J Infect Dis ; 205(5): 772-81, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22275401

RESUMO

BACKGROUND: Vaccine development in human Plasmodium falciparum malaria has been hampered by the exceptionally high levels of CD8(+) T cells required for efficacy. Use of potently immunogenic human adenoviruses as vaccine vectors could overcome this problem, but these are limited by preexisting immunity to human adenoviruses. METHODS: From 2007 to 2010, we undertook a phase I dose and route finding study of a new malaria vaccine, a replication-incompetent chimpanzee adenovirus 63 (ChAd63) encoding the preerythrocytic insert multiple epitope thrombospondin-related adhesion protein (ME-TRAP; n = 54 vaccinees) administered alone (n = 28) or with a modified vaccinia virus Ankara (MVA) ME-TRAP booster immunization 8 weeks later (n = 26). We observed an excellent safety profile. High levels of TRAP antigen-specific CD8(+) and CD4(+) T cells, as detected by interferon γ enzyme-linked immunospot assay and flow cytometry, were induced by intramuscular ChAd63 ME-TRAP immunization at doses of 5 × 10(10) viral particles and above. Subsequent administration of MVA ME-TRAP boosted responses to exceptionally high levels, and responses were maintained for up to 30 months postvaccination. CONCLUSIONS: The ChAd63 chimpanzee adenovirus vector appears safe and highly immunogenic, providing a viable alternative to human adenoviruses as vaccine vectors for human use. CLINICAL TRIALS REGISTRATION: NCT00890019.


Assuntos
Adenovirus dos Símios/imunologia , Vacinas Antimaláricas/administração & dosagem , Vacinas Antimaláricas/imunologia , Malária Falciparum/imunologia , Proteínas de Protozoários/imunologia , Vacinas de DNA/administração & dosagem , Vacinas de DNA/imunologia , Adenovirus dos Símios/genética , Animais , Anticorpos Neutralizantes/sangue , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Epitopos , Citometria de Fluxo , Humanos , Interferon gama/metabolismo , Interleucina-2/metabolismo , Vacinas Antimaláricas/efeitos adversos , Fator de Necrose Tumoral alfa/metabolismo , Vacinas de DNA/efeitos adversos
17.
Vaccines (Basel) ; 11(2)2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36851327

RESUMO

In the twenty-first century, newly emerging viruses which are mostly zoonotic or vector-borne have continuously threatened public health and caused outbreaks of global concern [...].

18.
Arch Med Res ; 54(3): 168-175, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36894463

RESUMO

The field of vaccine development has seen an increase in the number of rationally designed technologies that increase effectiveness against vaccine-resistant pathogens, while not compromising safety. Yet, there is still an urgent need to expand and further understand these platforms against complex pathogens that often evade protective responses. Nanoscale platforms have been at the center of new studies, especially in the wake of the coronavirus disease 2019 (COVID-19), with the aim of deploying safe and effective vaccines in a short time period. The intrinsic properties of protein-based nanoparticles, such as biocompatibility, flexible physicochemical characteristics, and variety have made them an attractive platform against different infectious disease agents. In the past decade, several studies have tested both lumazine synthase-, ferritin-, and albumin-based nanoplatforms against a wide range of complex pathogens in pre-clinical studies. Owed to their success in pre-clinical studies, several studies are undergoing human clinical trials or are near an initial phase. In this review we highlight the different protein-based platforms, mechanisms of synthesis, and effectiveness of these over the past decade. In addition, some challenges, and future directions to increase their effectiveness are also highlighted. Taken together, protein-based nanoscaffolds have proven to be an effective means to design rationally designed vaccines, especially against complex pathogens and emerging infectious diseases.


Assuntos
COVID-19 , Doenças Transmissíveis , Nanopartículas , Vacinas , Humanos , COVID-19/prevenção & controle , Vacinas/uso terapêutico , Nanopartículas/uso terapêutico , Nanopartículas/química , Imunidade Celular
19.
Vaccines (Basel) ; 11(3)2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36992153

RESUMO

Chikungunya virus (CHIKV) is considered a priority pathogen and a major threat to global health. While CHIKV infections may be asymptomatic, symptomatic patients can develop chikungunya fever (CHIKF) characterized by severe arthralgia which often transitions into incapacitating arthritis that could last for years and lead to significant loss in health-related quality of life. Yet, Chikungunya fever (CHIKF) remains a neglected tropical disease due to its complex epidemiology and the misrepresentation of its incidence and disease burden worldwide. Transmitted to humans by infected Aedes mosquitoes, CHIKV has dramatically expanded its geographic distribution to over 100 countries, causing large-scale outbreaks around the world and putting more than half of the population of the world at risk of infection. More than 50 years have passed since the first CHIKV vaccine was reported to be in development. Despite this, there is no licensed vaccine or antiviral treatments against CHIKV to date. In this review, we highlight the clinical relevance of developing chikungunya vaccines by discussing the poor understanding of long-term disease burden in CHIKV endemic countries, the complexity of CHIKV epidemiological surveillance, and emphasising the impact of the global emergence of CHIKV infections. Additionally, our review focuses on the recent progress of chikungunya vaccines in development, providing insight into the most advanced vaccine candidates in the pipeline and the potential implications of their roll-out.

20.
J Clin Med ; 12(4)2023 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-36835858

RESUMO

Manifestations of COVID-19 are diverse and range from asymptomatic to severe, critical illness and death. Cases requiring hospital care (in severe and critical illnesses) are associated with comorbidities and hyperactivation of the immune system. Therefore, in this exploratory observational study, we analyzed which parameters are associated with mortality. We evaluated: demographic characteristics (age, sex and comorbidities), laboratory data (albumin, leukocytes, lymphocytes, platelets, ferritin), days of hospital stay, interleukins (IL-2, IL-6, IL-7, IL-10, IL-17) and sP-selectin in 40 Mexican patients admitted to medical emergencies with a confirmed diagnosis of COVID-19, a complete clinical record, and who signed the informed consent. Twenty severe (they required intermediate care with non-invasive ventilation) and twenty critically ill patients (they required mechanical ventilation) were classified, and these were subsequently compared with healthy and recovered subjects. A significant difference was found between the hospitalized groups in the parameters of age, ferritin, days of hospital stay and death with p values = 0.0145, p = 0.0441, p = 0.0001 and p = 0.0001, respectively. In the determination of cytokines and P-selectin, a significant difference was found between the following groups: recovered patients and healthy volunteers compared with hospitalized patients in severe and critical condition. Importantly, IL-7 remained elevated one year later in recovered patients. Taken together, these values determined at the time of hospital admission could be useful to monitor patients closely and evaluate in-hospital progress, hospital discharge, and out-of-hospital progress.

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