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1.
Science ; 312(5779): 1530-3, 2006 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-16763152

RESUMO

Vaccine-induced cellular immunity controls virus replication in simian immunodeficiency virus (SIV)-infected monkeys only transiently, leading to the question of whether such vaccines for AIDS will be effective. We immunized monkeys with plasmid DNA and replication-defective adenoviral vectors encoding SIV proteins and then challenged them with pathogenic SIV. Although these monkeys demonstrated a reduction in viremia restricted to the early phase of SIV infection, they showed a prolonged survival. This survival was associated with preserved central memory CD4+ T lymphocytes and could be predicted by the magnitude of the vaccine-induced cellular immune response. These immune correlates of vaccine efficacy should guide the evaluation of AIDS vaccines in humans.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Memória Imunológica , Vacinas contra a SAIDS/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/imunologia , Vacinas de DNA/imunologia , Sequência de Aminoácidos , Animais , Humanos , Macaca mulatta , Dados de Sequência Molecular , Plasmídeos , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Análise de Sobrevida , Vacinas Sintéticas/imunologia , Replicação Viral
2.
AIDS Res Hum Retroviruses ; 22(5): 445-52, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16706622

RESUMO

Because of the importance of developing HIV vaccine strategies that generate cytotoxic T lymphocyte (CTL) responses with a maximal breadth of epitope recognition, we have explored a variety of novel strategies designed to overcome the usual propensity of CTLs to focus recognition on a limited number of dominant epitopes. In studies of rhesus monkeys expressing the Mamu-A*01 MHC class I allele, we show that variously configured multiepitope plasmid DNA vaccine constructs elicit CTL populations that do not evidence skewing of recognition to dominant epitopes. Nevertheless, repeated boosting of these vaccinated monkeys with different live recombinant vaccine vectors uncovers and amplifies the usual CTL epitope dominance hierarchy. Importantly, in vitro peptide stimulation of peripheral blood mononuclear cells from monkeys that have received only a multiepitope plasmid DNA priming immunization uncovers this dominance hierarchy. Therefore, the dominance hierarchy of the vaccine-elicited epitope-specific CTL populations is inherent in the T lymphocytes of the monkeys after initial exposure to epitope peptides, and the ultimate breadth of epitope recognition cannot be modified thereafter. This finding underscores the enormous challenge associated with increasing the breadth of CTL recognition through vaccination.


Assuntos
Epitopos de Linfócito T/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Epitopos Imunodominantes/imunologia , Linfócitos T Citotóxicos/imunologia , Vacinas de DNA/imunologia , Alelos , Animais , Técnicas In Vitro , Macaca mulatta , Peptídeos/imunologia , Plasmídeos/genética
3.
Nature ; 441(7090): 239-43, 2006 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-16625206

RESUMO

A common viral immune evasion strategy involves mutating viral surface proteins in order to evade host neutralizing antibodies. Such immune evasion tactics have not previously been intentionally applied to the development of novel viral gene delivery vectors that overcome the critical problem of anti-vector immunity. Recombinant, replication-incompetent adenovirus serotype 5 (rAd5) vector-based vaccines for human immunodeficiency virus type 1 and other pathogens have proved highly immunogenic in preclinical studies but will probably be limited by the high prevalence of pre-existing anti-Ad5 immunity in human populations, particularly in the developing world. Here we show that rAd5 vectors can be engineered to circumvent anti-Ad5 immunity. We constructed novel chimaeric rAd5 vectors in which the seven short hypervariable regions (HVRs) on the surface of the Ad5 hexon protein were replaced with the corresponding HVRs from the rare adenovirus serotype Ad48. These HVR-chimaeric rAd5 vectors were produced at high titres and were stable through serial passages in vitro. HVR-chimaeric rAd5 vectors expressing simian immunodeficiency virus Gag proved comparably immunogenic to parental rAd5 vectors in naive mice and rhesus monkeys. In the presence of high levels of pre-existing anti-Ad5 immunity, the immunogenicity of HVR-chimaeric rAd5 vectors was not detectably suppressed, whereas the immunogenicity of parental rAd5 vectors was abrogated. These data demonstrate that functionally relevant Ad5-specific neutralizing antibodies are focused on epitopes located within the hexon HVRs. Moreover, these studies show that recombinant viral vectors can be engineered to circumvent pre-existing anti-vector immunity by removing key neutralizing epitopes on the surface of viral capsid proteins. Such chimaeric viral vectors may have important practical implications for vaccination and gene therapy.


Assuntos
Adenoviridae/genética , Adenoviridae/imunologia , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/imunologia , Engenharia Genética , Vetores Genéticos/genética , Vetores Genéticos/imunologia , Adenoviridae/classificação , Adenoviridae/fisiologia , Animais , Linfócitos T CD8-Positivos/imunologia , DNA Recombinante/genética , Terapia Genética , Macaca mulatta/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Testes de Neutralização , Vacinas
4.
J Immunol ; 176(9): 5338-45, 2006 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-16622001

RESUMO

Functional impairment of virus-specific memory CD8(+) T lymphocytes has been associated with clinical disease progression following HIV, SIV, and simian human immunodeficiency virus infection. These lymphocytes have a reduced capacity to produce antiviral cytokines and mediators involved in the lysis of virally infected cells. In the present study, we used polychromatic flow cytometry to assess the frequency and functional capacity of central memory (CD28(+)CD95(+)) and effector memory (CD28(-)CD95(+)) subpopulations of Gag-specific CD8(+) T cells in SIV/simian human immunodeficiency virus-infected rhesus monkeys. The aim of this study was to determine whether Ag-specific, memory CD8(+) T cell function could be preserved in infected monkeys that had been immunized before infection with a vaccine regimen consisting of a plasmid DNA prime followed by a recombinant viral vector boost. We observed that vaccination was associated with the preservation of Gag-specific central memory CD8(+) T cells that were functionally capable of producing IFN-gamma, and effector memory CD8(+) T cells that were capable of producing granzyme B following viral Ag exposure.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Memória Imunológica/imunologia , Macaca mulatta/imunologia , Macaca mulatta/virologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/imunologia , Vacinas Virais/imunologia , Animais , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/virologia , Comunicação Celular/imunologia , Células Cultivadas , Progressão da Doença , Epitopos de Linfócito T/imunologia , Regulação da Expressão Gênica , Produtos do Gene gag/imunologia , Granzimas , Interferon gama/biossíntese , Macaca mulatta/metabolismo , Peptídeos/imunologia , Serina Endopeptidases/metabolismo , Síndrome de Imunodeficiência Adquirida dos Símios/metabolismo , Síndrome de Imunodeficiência Adquirida dos Símios/patologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia
5.
J Virol ; 80(4): 1645-52, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16439521

RESUMO

Because the vaccine vectors currently being evaluated in human populations all have significant limitations in their immunogenicity, novel vaccine strategies are needed for the elicitation of cell-mediated immunity. The nonpathogenic, rapidly growing mycobacterium Mycobacterium smegmatis was engineered as a vector expressing full-length human immunodeficiency virus type 1 (HIV-1) HXBc2 envelope protein. Immunization of mice with recombinant M. smegmatis led to the expansion of major histocompatibility complex class I-restricted HIV-1 epitope-specific CD8(+) T cells that were cytolytic and secreted gamma interferon. Effector and memory T lymphocytes were elicited, and repeated immunization generated a stable central memory pool of virus-specific cells. Importantly, preexisting immunity to Mycobacterium bovis BCG had only a marginal effect on the immunogenicity of recombinant M. smegmatis. This mycobacterium may therefore be a useful vaccine vector.


Assuntos
Vacinas contra a AIDS/imunologia , Linfócitos T CD8-Positivos/imunologia , Genes env , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/imunologia , Mycobacterium smegmatis/genética , Animais , Vacinas Bacterianas/imunologia , Testes Imunológicos de Citotoxicidade , Feminino , Imunização , Memória Imunológica , Interferon gama/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium bovis , Mycobacterium smegmatis/imunologia , Vacinas Sintéticas/imunologia
6.
J Immunol ; 176(1): 319-28, 2006 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-16365424

RESUMO

Because the control of HIV-1 replication is largely dependent on CD8+ T lymphocyte responses specific for immunodominant viral epitopes, vaccine strategies that increase the breadth of dominant epitope-specific responses should contribute to containing HIV-1 spread. Developing strategies to elicit such broad immune responses will require an understanding of the mechanisms responsible for focusing CD8+ T lymphocyte recognition on a limited number of epitopes. To explore this biology, we identified cohorts of rhesus monkeys that expressed the MHC class I molecules Mamu-A*01, Mamu-A*02, or both, and assessed the evolution of their dominant epitope-specific CD8+ T lymphocyte responses (Gag p11C- and Tat TL8-specific in the Mamu-A*01+ and Nef p199RY-specific in the Mamu-A*02+ monkeys) following acute SIV infection. The Mamu-A*02+ monkeys that also expressed Mamu-A*01 exhibited a significant delay in the evolution of the CD8+ T lymphocyte responses specific for the dominant Mamu-A*02-restricted SIV epitope, Nef p199RY. This delay in kinetics was not due to differences in viral load kinetics or magnitude or in viral escape mutations, but was associated with the evolution of the Mamu-A*01-restricted CD8+ T lymphocyte responses to the highly dominant SIV epitopes Gag p11C and Tat TL8. Thus, the evolution of dominant epitope-specific CD8+ T lymphocyte responses can be suppressed by other dominant epitope-specific responses, and this immunodomination is important in determining the kinetics of dominant epitope-specific responses.


Assuntos
Antígenos Virais/imunologia , Linfócitos T CD8-Positivos/imunologia , Epitopos de Linfócito T/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Epitopos Imunodominantes/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Sequência de Aminoácidos , Animais , Epitopos de Linfócito T/genética , Epitopos Imunodominantes/genética , Macaca mulatta , Dados de Sequência Molecular , Mutação , Reação em Cadeia da Polimerase , Vírus da Imunodeficiência Símia/imunologia
7.
Immunology ; 116(4): 443-53, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16313358

RESUMO

The development of successful vaccination strategies for eliciting cytotoxic T lymphocytes (CTLs) will be facilitated by the definition of strategies for subdividing CTLs into functionally distinct subpopulations. We assessed whether surface expression of a number of cell-surface proteins could be used to define functionally distinct subpopulations of memory CTLs in mice immunized with a recombinant vaccinia virus expressing human immunodeficiency virus (HIV)-1 envelope (Env). We found changes in cell-surface expression of CD11a, CD44, CD45RB, CD49d, CD54 and CD62L on Env-specific CD8(+) T cells that appeared to differentiate them from other CD8(+) T cells within 1 week to 1 month following immunization. Further, we saw an up-regulation of CD62L surface expression on Env-specific CD8(+) memory T cells several months after immunization. However, CD62L expression did not correlate with differences in the abilities of CTLs to proliferate or produce interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) in vitro in response to Env peptide stimulation. Moreover, the expression of CD62L did not allow differentiation of CTLs into subpopulations with distinct expansion kinetics in vivo after adoptive transfer into naïve mice and subsequent boosting of these mice with a recombinant adenovirus expressing HIV-1 Env. Therefore, the definition of memory CD8(+) T-cell subpopulations on the basis of CD62L expression in mice does not allow the delineation of functionally distinct CTL subpopulations.


Assuntos
Vacinas contra a AIDS/imunologia , Selectina L/metabolismo , Subpopulações de Linfócitos T/imunologia , Linfócitos T Citotóxicos/imunologia , Animais , Biomarcadores/metabolismo , Proliferação de Células , Feminino , Memória Imunológica , Imunofenotipagem , Interferon gama/biossíntese , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Baço/imunologia , Fator de Necrose Tumoral alfa/biossíntese , Vacinação
8.
J Virol ; 79(22): 14161-8, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16254351

RESUMO

Preexisting immunity to adenovirus serotype 5 (Ad5) has been shown to suppress the immunogenicity of recombinant Ad5 (rAd5) vector-based vaccines for human immunodeficiency virus type 1 (HIV-1) in both preclinical studies and clinical trials. A potential solution to this problem is to utilize rAd vectors derived from rare Ad serotypes, such as Ad35. However, rAd35 vectors have appeared less immunogenic than rAd5 vectors in preclinical studies to date. In this study, we explore the hypothesis that the differences in immunogenicity between rAd5 and rAd35 vectors may be due in part to differences between the fiber proteins of these viruses. We constructed capsid chimeric rAd35 vectors containing the Ad5 fiber knob (rAd35k5) and compared the immunogenicities of rAd5, rAd35k5, and rAd35 vectors expressing simian immunodeficiency virus Gag and HIV-1 Env in mice and rhesus monkeys. In vitro studies demonstrated that rAd35k5 vectors utilized the Ad5 receptor CAR rather than the Ad35 receptor CD46. In vivo studies showed that rAd35k5 vectors were more immunogenic than rAd35 vectors in both mice and rhesus monkeys. These data suggest that the Ad5 fiber knob contributes substantially to the immunogenicity of rAd vectors. Moreover, these studies demonstrate that capsid chimeric rAd vectors can be constructed to combine beneficial immunologic and serologic properties of different Ad serotypes.


Assuntos
Infecções por Adenoviridae/imunologia , Adenoviridae/imunologia , Proteínas do Capsídeo/genética , Vacinas Virais , Adenoviridae/classificação , Adenoviridae/genética , Animais , Epitopos/química , Epitopos/imunologia , Imunização , Macaca mulatta , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Sorotipagem , Replicação Viral
9.
J Virol ; 79(15): 9694-701, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16014931

RESUMO

The high prevalence of preexisting immunity to adenovirus serotype 5 (Ad5) in human populations will likely limit the immunogenicity and clinical utility of recombinant Ad5 (rAd5) vector-based vaccines for human immunodeficiency virus type 1 and other pathogens. A potential solution to this problem is to utilize rAd vaccine vectors derived from rare Ad serotypes such as Ad35 and Ad11. We have previously reported that rAd35 vectors were immunogenic in the presence of anti-Ad5 immunity, but the immunogenicity of heterologous rAd prime-boost regimens and the extent that cross-reactive anti-vector immunity may limit this approach have not been fully explored. Here we assess the immunogenicity of heterologous vaccine regimens involving rAd5, rAd35, and novel rAd11 vectors expressing simian immunodeficiency virus Gag in mice both with and without anti-Ad5 immunity. Heterologous rAd prime-boost regimens proved significantly more immunogenic than homologous regimens, as expected. Importantly, all regimens that included rAd5 were markedly suppressed by anti-Ad5 immunity. In contrast, rAd35-rAd11 and rAd11-rAd35 regimens elicited high-frequency immune responses both in the presence and in the absence of anti-Ad5 immunity, although we also detected clear cross-reactive Ad35/Ad11-specific humoral and cellular immune responses. Nevertheless, these data suggest the potential utility of heterologous rAd prime-boost vaccine regimens using vectors derived from rare human Ad serotypes.


Assuntos
Adenovírus Humanos/imunologia , Vetores Genéticos/imunologia , Vírus Reordenados/imunologia , Vacinas Virais/imunologia , Animais , Formação de Anticorpos , Reações Cruzadas , Avaliação Pré-Clínica de Medicamentos , Produtos do Gene gag/genética , Terapia Genética , Imunidade Celular , Imunização Secundária , Injeções Intramusculares , Camundongos , Camundongos Endogâmicos C57BL , Vírus da Imunodeficiência Símia/genética , Vacinas Sintéticas/imunologia , Vacinas Virais/administração & dosagem
10.
J Immunol ; 174(11): 7179-85, 2005 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-15905562

RESUMO

The utility of recombinant adenovirus serotype 5 (rAd5) vector-based vaccines for HIV-1 and other pathogens will likely be limited by the high prevalence of pre-existing Ad5-specific neutralizing Abs (NAbs) in human populations. However, the immunodominant targets of Ad5-specific NAbs in humans remain poorly characterized. In this study, we assess the titers and primary determinants of Ad5-specific NAbs in individuals from both the United States and the developing world. Importantly, median Ad5-specific NAb titers were >10-fold higher in sub-Saharan Africa compared with the United States. Moreover, hexon-specific NAb titers were 4- to 10-fold higher than fiber-specific NAb titers in these cohorts by virus neutralization assays using capsid chimeric viruses. We next performed adoptive transfer studies in mice to evaluate the functional capacity of hexon- and fiber-specific NAbs to suppress the immunogenicity of a prototype rAd5-Env vaccine. Hexon-specific NAbs were remarkably efficient at suppressing Env-specific immune responses elicited by the rAd5 vaccine. In contrast, fiber-specific NAbs exerted only minimal suppressive effects on rAd5 vaccine immunogenicity. These data demonstrate that functionally significant Ad5-specific NAbs are directed primarily against the Ad5 hexon protein in both humans and mice. These studies suggest a potential strategy for engineering novel Ad5 vectors to evade dominant Ad5-specific NAbs.


Assuntos
Adenovírus Humanos/imunologia , Anticorpos Antivirais/fisiologia , Proteínas do Capsídeo/imunologia , Vetores Genéticos/imunologia , Vacinas de DNA/imunologia , Vacinas Virais/imunologia , Adenovírus Humanos/genética , Adulto , Animais , Anticorpos Antivirais/biossíntese , Anticorpos Antivirais/sangue , Proteínas do Capsídeo/administração & dosagem , Proteínas do Capsídeo/genética , Relação Dose-Resposta Imunológica , Vetores Genéticos/administração & dosagem , Vetores Genéticos/metabolismo , Humanos , Epitopos Imunodominantes/genética , Epitopos Imunodominantes/imunologia , Epitopos Imunodominantes/metabolismo , Imunossupressores/metabolismo , Imunossupressores/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Testes de Neutralização , Estudos Soroepidemiológicos , Vacinas de DNA/administração & dosagem , Vacinas de DNA/genética , Vacinas Virais/administração & dosagem , Vacinas Virais/genética
11.
J Immunol ; 174(8): 4753-60, 2005 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-15814700

RESUMO

Production of IL-2 and IFN-gamma by CD4+ T lymphocytes is important for the maintenance of a functional immune system in infected individuals. In the present study, we assessed the cytokine production profiles of functionally distinct subsets of CD4+ T lymphocytes in rhesus monkeys infected with pathogenic or attenuated SIV/simian human immunodeficiency virus (SHIV) isolates, and these responses were compared with those in vaccinated monkeys that were protected from immunodeficiency following pathogenic SHIV challenge. We observed that preserved central memory CD4+ T lymphocyte production of SIV/SHIV-induced IL-2 was associated with disease protection following primate lentivirus infection. Persisting clinical protection in vaccinated and challenged monkeys is thus correlated with a preserved capacity of the peripheral blood central memory CD4+ T cells to express this important immunomodulatory cytokine.


Assuntos
Linfócitos T CD4-Positivos/imunologia , HIV/imunologia , Interleucina-2/biossíntese , Vírus da Imunodeficiência Símia/imunologia , Vacinas contra a AIDS/farmacologia , Animais , Antígenos CD28/metabolismo , Produtos do Gene gag , HIV/patogenicidade , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Infecções por HIV/virologia , Humanos , Memória Imunológica , Técnicas In Vitro , Interferon gama/biossíntese , Macaca mulatta , RNA Viral/sangue , Vacinas contra a SAIDS/farmacologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/patogenicidade , Subpopulações de Linfócitos T/imunologia , Fator de Necrose Tumoral alfa/biossíntese , Receptor fas/metabolismo
12.
J Virol ; 79(10): 6516-22, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15858035

RESUMO

The magnitude and durability of immune responses induced by replication-defective adenovirus serotype 5 (ADV5) vector-based vaccines were evaluated in the simian-human immunodeficiency virus/rhesus monkey model. A single inoculation of recombinant ADV5 vector constructs induced cellular and humoral immunity, but the rapid generation of neutralizing anti-Ad5 antibodies limited the immunity induced by repeated vector administration. The magnitude and durability of the immune responses elicited by these vaccines were greater when they were delivered as boosting immunogens in plasmid DNA-primed monkeys than when they were used as single-modality immunogens. Therefore, administration of ADV5-based vectors in DNA-primed subjects may be a preferred use of this vaccine modality for generating long-term immune protection.


Assuntos
Adenovírus Humanos/imunologia , Anticorpos Antivirais/sangue , Vetores Genéticos/imunologia , Infecções por HIV/imunologia , Imunização Secundária , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Linfócitos T/imunologia , Vacinação , Vacinas Virais/imunologia , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/imunologia , Proteínas E1 de Adenovirus/genética , Proteínas E3 de Adenovirus/genética , Adenovírus Humanos/genética , Animais , Avaliação Pré-Clínica de Medicamentos , Deleção de Genes , Vetores Genéticos/genética , Anticorpos Anti-HIV/sangue , HIV-1/genética , HIV-1/imunologia , Injeções Intramusculares , Macaca mulatta , Testes de Neutralização , Plasmídeos/genética , Síndrome de Imunodeficiência Adquirida dos Símios/sangue , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/imunologia , Vacinas de DNA/administração & dosagem , Vacinas de DNA/imunologia , Vacinas Virais/administração & dosagem
13.
Nat Immunol ; 6(3): 247-52, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15685174

RESUMO

Viral escape from cytotoxic T lymphocytes (CTLs) can undermine immune control of human immunodeficiency virus 1. It is therefore important to assess the stability of viral mutations in CTL epitopes after transmission to naive hosts. Here we demonstrate the persistence of mutations in a dominant CTL epitope after transmission of simian immunodeficiency virus variants to major histocompatibility complex-matched rhesus monkeys. Transient reversions to wild-type sequences occurred and elicited CTLs specific for the wild-type epitope, resulting in immunological pressure that rapidly reselected the mutant viruses. These data suggest that mutations in dominant human immunodeficiency virus 1 CTL epitopes may accumulate in human populations with limited major histocompatibility complex heterogeneity by a mechanism involving dynamic CTL control of transiently reverted wild-type virus.


Assuntos
Epitopos de Linfócito T/imunologia , Mutação , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/imunologia , Linfócitos T Citotóxicos/imunologia , Animais , Epitopos de Linfócito T/genética , Humanos , Epitopos Imunodominantes/genética , Macaca mulatta , Complexo Principal de Histocompatibilidade/imunologia , Vírus da Imunodeficiência Símia/patogenicidade
14.
J Clin Invest ; 114(9): 1334-42, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15520866

RESUMO

DCs are critical for priming adaptive immune responses to foreign antigens. However, the utility of harnessing these cells in vivo to optimize the immunogenicity of vaccines has not been fully explored. Here we investigate a novel vaccine approach that involves delivering synergistic signals that both recruit and expand DC populations at the site of antigen production. Intramuscular injection of an unadjuvanted HIV-1 envelope (env) DNA vaccine recruited few DCs to the injection site and elicited low-frequency, env-specific immune responses in mice. Coadministration of plasmids encoding the chemokine macrophage inflammatory protein-1alpha (MIP-1alpha) and the DC-specific growth factor fms-like tyrosine kinase 3 ligand with the DNA vaccine resulted in the recruitment, expansion, and activation of large numbers of DCs at the site of inoculation. Consistent with these findings, coadministration of these plasmid cytokines also markedly augmented DNA vaccine---elicited cellular and humoral immune responses and increased protective efficacy against challenge with recombinant vaccinia virus. These data suggest that the availability of mature DCs at the site of inoculation is a critical rate-limiting factor for DNA vaccine immunogenicity. Synergistic recruitment and expansion of DCs in vivo may prove a practical strategy for overcoming this limitation and potentiating immune responses to vaccines as well as other immunotherapeutic strategies.


Assuntos
Células Dendríticas/citologia , Imunoterapia/métodos , Vacinas de DNA , Animais , Vacinas Anticâncer , Quimiocina CCL3 , Quimiocina CCL4 , Quimiotaxia , Citocinas/metabolismo , DNA Viral , Células Dendríticas/metabolismo , Ensaio de Imunoadsorção Enzimática , Epitopos/química , HIV-1/genética , Imuno-Histoquímica , Proteínas Inflamatórias de Macrófagos/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Plasmídeos/metabolismo , Fatores de Tempo , Vaccinia virus/genética
15.
Nat Biotechnol ; 22(11): 1429-34, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15502816

RESUMO

In this study we extend tetramerization technology to T-cell receptors (TCRs). We identified TCR alpha beta pairs in the absence of accessory molecules, ensuring isolation of high-affinity TCRs that maintain stable binding characteristics after tetramerization. Subtle changes in cognate peptide levels bound to the class I molecule were accurately reflected by parallel changes in the mean fluorescence intensity of cells that bound TCR tetramers, allowing us to accurately assess the binding affinity of a panel of peptides to major histocompatibility complex (MHC) class I. Using a TCR tetramer specific for the Mamu-A(*)01 allele, we identified animals expressing this restricting class I allele from a large cohort of outbred rhesus macaques. TCR tetramers should facilitate analysis of the MHC-peptide interface and, more generally, the design of immunotherapeutics and vaccines.


Assuntos
Imunoensaio de Fluorescência por Polarização/métodos , Genes MHC Classe I/imunologia , Engenharia de Proteínas/métodos , Mapeamento de Interação de Proteínas/métodos , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Linfócitos T/imunologia , Animais , Complexo Antígeno-Anticorpo/análise , Reações Antígeno-Anticorpo/imunologia , Células Cultivadas , Dimerização , Genes MHC Classe I/genética , Macaca mulatta , Complexos Multiproteicos/genética , Complexos Multiproteicos/imunologia , Ligação Proteica , Receptores de Antígenos de Linfócitos T alfa-beta/genética
16.
J Infect Dis ; 190(5): 998-1005, 2004 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-15295708

RESUMO

The development of an improved vaccine for controlling measles virus (MV) infections in the developing world will require an understanding of the immune mechanisms responsible for the clearance of this virus. To evaluate the role of humoral immunity in the containment of MV, rhesus monkeys were treated at the time of MV challenge with either anti-CD20 monoclonal antibody (MAb) infusion, to deplete B lymphocytes, or both anti-CD20 and anti-CD8 MAb, to deplete both B lymphocytes and CD8+ effector T lymphocytes. Although the MV-specific antibody response in CD20+ lymphocyte-depleted monkeys was delayed by >1 week, the kinetics of MV clearance did not differ from those for monkeys that received control MAb. Furthermore, unusual clinical sequelae of MV infection were not observed in these monkeys. In contrast, MV-infected rhesus monkeys depleted of both CD20+ and CD8+ lymphocytes had a prolonged duration of viremia and developed a desquamating skin rash. These findings indicate that humoral immunity plays a limited role in the control of MV replication in an MV-naive individual and suggest that new measles vaccination strategies should focus on the elicitation of cell-mediated immune responses, in addition to neutralizing antibodies, to facilitate rapid elimination of locally replicating virus.


Assuntos
Anticorpos Antivirais/imunologia , Formação de Anticorpos , Vírus do Sarampo/patogenicidade , Sarampo/virologia , Viremia/virologia , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/administração & dosagem , Anticorpos Antivirais/sangue , Antígenos CD20/imunologia , Linfócitos B/imunologia , Linfócitos T CD8-Positivos/imunologia , Modelos Animais de Doenças , Humanos , Depleção Linfocítica , Macaca mulatta , Sarampo/imunologia , Vírus do Sarampo/imunologia , Viremia/imunologia
17.
Proc Natl Acad Sci U S A ; 101(30): 11088-93, 2004 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-15258286

RESUMO

Although a consensus has emerged that an HIV vaccine should elicit a cytotoxic T lymphocyte (CTL) response, the characteristics of an effective vaccine-induced T lymphocyte response remain unclear. We explored this issue in the simian human immunodeficiency virus/rhesus monkey model in the course of assessing the relative immunogenicity of vaccine regimens that included a cytokine-augmented plasmid DNA prime and a boost with DNA or recombinant pox vectors. Recombinant vaccinia virus, recombinant modified vaccinia Ankara (MVA), and recombinant fowlpox were comparable in their immunogenicity. Moreover, whereas the magnitude of the peak vaccine-elicited T lymphocyte responses in the recombinant pox virus-boosted monkeys was substantially greater than that seen in the monkeys immunized with plasmid DNA alone, the magnitudes of recombinant pox boosted CTL responses decayed rapidly and were comparable to those of the DNA-alone-vaccinated monkeys by the time of viral challenge. Consistent with these comparable memory T cell responses, the clinical protection seen in all groups of experimentally vaccinated monkeys was similar. This study, therefore, indicates that the steady-state memory, rather than the peak effector vaccine-elicited T lymphocyte responses, may be the critical immune correlate of protection for a CTL-based HIV vaccine.


Assuntos
Memória Imunológica , Poxviridae/genética , Linfócitos T Citotóxicos/imunologia , Linfócitos T/imunologia , Animais , Contagem de Linfócito CD4 , Linfócitos T CD8-Positivos/imunologia , Ensaio de Imunoadsorção Enzimática , Contagem de Linfócitos , Macaca mulatta , Reação em Cadeia da Polimerase/métodos , RNA Viral/imunologia , Mapeamento por Restrição , Vaccinia virus/genética , Vacinas Virais/imunologia
18.
J Immunol ; 172(10): 6290-7, 2004 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-15128818

RESUMO

The high prevalence of pre-existing immunity to adenovirus serotype 5 (Ad5) in human populations may substantially limit the immunogenicity and clinical utility of recombinant Ad5 vector-based vaccines for HIV-1 and other pathogens. A potential solution to this problem is to use vaccine vectors derived from adenovirus (Ad) serotypes that are rare in humans, such as Ad35. However, cross-reactive immune responses between heterologous Ad serotypes have been described and could prove a major limitation of this strategy. In particular, the extent of immunologic cross-reactivity between Ad5 and Ad35 has not previously been determined. In this study we investigate the impact of pre-existing anti-Ad5 immunity on the immunogenicity of candidate rAd5 and rAd35 vaccines expressing SIV Gag in mice. Anti-Ad5 immunity at levels typically found in humans dramatically blunted the immunogenicity of rAd5-Gag. In contrast, even high levels of anti-Ad5 immunity did not substantially suppress Gag-specific cellular immune responses elicited by rAd35-Gag. Low levels of cross-reactive Ad5/Ad35-specific CD4(+) T lymphocyte responses were observed, but were insufficient to suppress vaccine immunogenicity. These data demonstrate the potential utility of Ad35 as a candidate vaccine vector that is minimally suppressed by anti-Ad5 immunity. Moreover, these studies suggest that using Ad vectors derived from immunologically distinct serotypes may be an effective and general strategy to overcome the suppressive effects of pre-existing anti-Ad immunity.


Assuntos
Infecções por Adenoviridae/imunologia , Infecções por Adenoviridae/prevenção & controle , Adenoviridae/genética , Adenoviridae/imunologia , Vacinas Virais/genética , Vacinas Virais/imunologia , Adenoviridae/classificação , Sequência de Aminoácidos , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Relação Dose-Resposta Imunológica , Mapeamento de Epitopos/métodos , Epitopos de Linfócito T/sangue , Produtos do Gene gag/administração & dosagem , Produtos do Gene gag/sangue , Produtos do Gene gag/imunologia , Vetores Genéticos , Imunidade Ativa , Esquemas de Imunização , Imunização Secundária , Injeções Intramusculares , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/metabolismo , Ligação Proteica/imunologia , Sorotipagem , Vírus da Imunodeficiência Símia/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia , Vacinas Virais/administração & dosagem
19.
Eur J Immunol ; 34(4): 1011-20, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15048711

RESUMO

The immunogenicity of plasmid DNA vaccines may be limited by the availability of professional antigen-presenting cells (APC) at the site of inoculation. Here we demonstrate that the types of APC recruited to the injection site can selectively modulate CD4(+) or CD8(+) T lymphocyte responses elicited by an HIV-1 Env DNA vaccine in mice. Coadministration of plasmid GM-CSF with the DNA vaccine resulted in the recruitment of macrophages to the site of inoculation and specifically augmented vaccine-elicited CD4(+) T lymphocyte responses. In contrast, coadministration of plasmid MIP-1 alpha with the DNA vaccine resulted in the recruitment of dendritic cells to the injection site and enhanced vaccine-elicited CD8(+) T lymphocyte responses. Interestingly, coadministration of both plasmid GM-CSF and plasmid MIP-1 alpha with the DNA vaccine recruited both macrophages and dendritic cells and led to a synergistic and sustained augmentation of CD4(+)and CD8(+) T lymphocyte responses. These data demonstrate the critical importance of locally recruited professional APC in determining the magnitude and nature of immune responses elicited by plasmid DNA vaccines. Moreover, these studies show that different subsets of professional APC can selectively modulate DNA vaccine-elicited T lymphocyte responses.


Assuntos
Células Apresentadoras de Antígenos/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Vacinas de DNA/imunologia , Animais , Quimiocina CCL4 , Quimiotaxia de Leucócito/imunologia , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Imuno-Histoquímica , Ativação Linfocitária/imunologia , Proteínas Inflamatórias de Macrófagos/imunologia , Camundongos
20.
J Virol ; 78(6): 2666-73, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14990686

RESUMO

The high prevalence of preexisting immunity to adenovirus serotype 5 (Ad5) in human populations will likely limit the immunogenicity and clinical utility of recombinant Ad5 vector-based vaccines for human immunodeficiency virus type 1 and other pathogens. Ad5-specific neutralizing antibodies (NAbs) are thought to contribute substantially to anti-Ad5 immunity, but the potential importance of Ad5-specific T lymphocytes in this setting has not been fully characterized. Here we assess the relative contributions of Ad5-specific humoral and cellular immune responses in blunting the immunogenicity of a rAd5-Env vaccine in mice. Adoptive transfer of Ad5-specific NAbs resulted in a dramatic abrogation of Env-specific immune responses following immunization with rAd5-Env. Interestingly, adoptive transfer of Ad5-specific CD8(+) T lymphocytes also resulted in a significant and durable suppression of rAd5-Env immunogenicity. These data demonstrate that NAbs and CD8(+) T lymphocytes both contribute to immunity to Ad5. Novel adenovirus vectors that are currently being developed to circumvent the problem of preexisting anti-Ad5 immunity should therefore be designed to evade both humoral and cellular Ad5-specific immune responses.


Assuntos
Infecções por Adenovirus Humanos/imunologia , Adenovírus Humanos/imunologia , Anticorpos Antivirais/sangue , Linfócitos T CD8-Positivos/imunologia , Vetores Genéticos , Vacinas Virais/imunologia , Infecções por Adenovirus Humanos/virologia , Adenovírus Humanos/classificação , Adenovírus Humanos/genética , Transferência Adotiva , Animais , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Testes de Neutralização , Sorotipagem , Vacinas Virais/genética
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