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1.
Mol Ther Oncolytics ; 19: 240-252, 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33209979

RESUMO

Prime-boost vaccination employing heterologous viral vectors encoding an antigen is an effective strategy to maximize the antigen-specific immune response. Replication-deficient adenovirus serotype 5 (Ad5) is currently being evaluated clinically in North America as a prime in conjunction with oncolytic rhabdovirus Maraba virus (MG1) as a boost. The use of an oncolytic rhabdovirus encoding a tumor antigen elicits a robust anti-cancer immune response and extends survival in murine models of cancer. Given the prevalence of pre-existing immunity to Ad5 globally, we explored the potential use of DEC205-targeted antibodies as an alternative agent to prime antigen-specific responses ahead of boosting with an oncolytic rhabdovirus expressing the same antigen. We found that a prime-boost vaccination strategy, consisting of an anti-DEC205 antibody fused to the model antigen ovalbumin (OVA) as a prime and oncolytic rhabdovirus-OVA as a boost, led to the formation of a robust antigen-specific immune response and improved survival in a B16-OVA tumor model. Overall, our study shows that anti-DEC205 antibodies fused to cancer antigens are effective to prime oncolytic rhabdovirus-boosted cancer antigen responses and may provide an alternative for patients with pre-existing immunity to Ad5 in humans.

2.
Commun Biol ; 3(1): 254, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444806

RESUMO

We have demonstrated that microtubule destabilizing agents (MDAs) can sensitize tumors to oncolytic vesicular stomatitis virus (VSVΔ51) in various preclinical models of cancer. The clinically approved T-DM1 (Kadcyla®) is an antibody-drug conjugate consisting of HER2-targeting trastuzumab linked to the potent MDA and maytansine derivative DM1. We reveal that combining T-DM1 with VSVΔ51 leads to increased viral spread and tumor killing in trastuzumab-binding, VSVΔ51-resistant cancer cells. In vivo, co-treatment of VSVΔ51 and T-DM1 increased overall survival in HER2-overexpressing, but trastuzumab-refractory, JIMT1 human breast cancer xenografts compared to monotherapies. Furthermore, viral spread in cultured HER2+ human ovarian cancer patient-derived ascites samples was enhanced by the combination of VSVΔ51 and T-DM1. Our data using the clinically approved Kadcyla® in combination with VSVΔ51 demonstrates proof of concept that targeted delivery of a viral-sensitizing molecule using an antibody-drug conjugate can enhance oncolytic virus activity and provides rationale for translation of this approach.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Neoplasias da Mama/terapia , Sinergismo Farmacológico , Terapia Viral Oncolítica/métodos , Rhabdoviridae/genética , Animais , Apoptose , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células , Terapia Combinada , Feminino , Humanos , Maitansina/administração & dosagem , Camundongos , Camundongos Nus , Trastuzumab/administração & dosagem , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Oncoimmunology ; 7(7): e1445459, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29900060

RESUMO

Prostate cancer (PCa) was estimated to have the second highest global incidence rate for male non-skin tumors and is the fifth most deadly in men thus mandating the need for novel treatment options. MG1-Maraba is a potent and versatile oncolytic virus capable of lethally infecting a variety of prostatic tumor cell lines alongside primary PCa biopsies and exerts direct oncolytic effects against large TRAMP-C2 tumors in vivo. An oncolytic immunotherapeutic strategy utilizing a priming vaccine and intravenously administered MG1-Maraba both expressing the human six-transmembrane antigen of the prostate (STEAP) protein generated specific CD8+ T-cell responses against multiple STEAP epitopes and resulted in functional breach of tolerance. Treatment of mice with bulky TRAMP-C2 tumors using oncolytic STEAP immunotherapy induced an overt delay in tumor progression, marked intratumoral lymphocytic infiltration with an active transcriptional profile and up-regulation of MHC class I. The preclinical data generated here offers clear rationale for clinically evaluating this approach for men with advanced PCa.

4.
Sci Immunol ; 3(23)2018 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-29752301

RESUMO

Mycobacterium tuberculosis (Mtb) is one of the most ancient human pathogens, yet the exact mechanism(s) of host defense against Mtb remains unclear. Although one-third of the world's population is chronically infected with Mtb, only 5 to 10% develop active disease. This indicates that, in addition to resistance mechanisms that control bacterial burden, the host has also evolved strategies to tolerate the presence of Mtb to limit disease severity. We identify mitochondrial cyclophilin D (CypD) as a critical checkpoint of T cell metabolism that controls the expansion of activated T cells. Although loss of CypD function in T cells led to enhanced Mtb antigen-specific T cell responses, this increased T cell response had no impact on bacterial burden. Rather, mice containing CypD-deficient T cells exhibited substantially compromised disease tolerance and succumbed to Mtb infection. This study establishes a mechanistic link between T cell-mediated immunity and disease tolerance during Mtb infection.


Assuntos
Ciclofilinas/imunologia , Mitocôndrias/imunologia , Linfócitos T/imunologia , Tuberculose Pulmonar/imunologia , Animais , Ciclofilina D , Ciclofilinas/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mycobacterium tuberculosis
5.
Cell ; 172(1-2): 176-190.e19, 2018 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-29328912

RESUMO

The dogma that adaptive immunity is the only arm of the immune response with memory capacity has been recently challenged by several studies demonstrating evidence for memory-like innate immune training. However, the underlying mechanisms and location for generating such innate memory responses in vivo remain unknown. Here, we show that access of Bacillus Calmette-Guérin (BCG) to the bone marrow (BM) changes the transcriptional landscape of hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs), leading to local cell expansion and enhanced myelopoiesis at the expense of lymphopoiesis. Importantly, BCG-educated HSCs generate epigenetically modified macrophages that provide significantly better protection against virulent M. tuberculosis infection than naïve macrophages. By using parabiotic and chimeric mice, as well as adoptive transfer approaches, we demonstrate that training of the monocyte/macrophage lineage via BCG-induced HSC reprogramming is sustainable in vivo. Our results indicate that targeting the HSC compartment provides a novel approach for vaccine development.


Assuntos
Células-Tronco Hematopoéticas/imunologia , Imunidade Inata , Memória Imunológica , Mycobacterium bovis/imunologia , Transcriptoma , Animais , Linhagem Celular , Células Cultivadas , Epigênese Genética , Hematopoese , Camundongos , Camundongos Endogâmicos C57BL , Tuberculose/imunologia
6.
Mol Ther ; 26(1): 56-69, 2018 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-29175158

RESUMO

Oncolytic viruses (OV) are an emerging class of anticancer bio-therapeutics that induce antitumor immunity through selective replication in tumor cells. However, the efficacy of OVs as single agents remains limited. We introduce a strategy that boosts the therapeutic efficacy of OVs by combining their activity with immuno-modulating, small molecule protein tyrosine phosphatase inhibitors. We report that vanadium-based phosphatase inhibitors enhance OV infection in vitro and ex vivo, in resistant tumor cell lines. Furthermore, vanadium compounds increase antitumor efficacy in combination with OV in several syngeneic tumor models, leading to systemic and durable responses, even in models otherwise refractory to OV and drug alone. Mechanistically, this involves subverting the antiviral type I IFN response toward a death-inducing and pro-inflammatory type II IFN response, leading to improved OV spread, increased bystander killing of cancer cells, and enhanced antitumor immune stimulation. Overall, we showcase a new ability of vanadium compounds to simultaneously maximize viral oncolysis and systemic anticancer immunity, offering new avenues for the development of improved immunotherapy strategies.


Assuntos
Vetores Genéticos/genética , Terapia Viral Oncolítica , Vírus Oncolíticos/genética , Compostos de Vanádio/farmacologia , Animais , Biomarcadores , Quimiocina CXCL9/metabolismo , Terapia Combinada , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Terapia Genética/métodos , Humanos , Imunoterapia , Mediadores da Inflamação/metabolismo , Interferon Tipo I/metabolismo , Interferon gama/metabolismo , Ativação Linfocitária/imunologia , Camundongos , Mortalidade , Espécies Reativas de Oxigênio/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Int J Cancer ; 141(6): 1257-1264, 2017 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-28568891

RESUMO

The poor prognosis of patients with advanced bone and soft-tissue sarcoma has not changed in the past several decades, highlighting the necessity for new therapeutic approaches. Immunotherapies, including oncolytic viral (OV) therapy, have shown great promise in a number of clinical trials for a variety of tumor types. However, the effective application of OV in treating sarcoma still remains to be demonstrated. Although few pre-clinical studies using distinct OVs have been performed and demonstrated therapeutic benefit in sarcoma models, a side-by-side comparison of clinically relevant OV platforms has not been performed. Four clinically relevant OV platforms (Reovirus, Vaccinia virus, Herpes-simplex virus and Rhabdovirus) were screened for their ability to infect and kill human and canine sarcoma cell lines in vitro, and human sarcoma specimens ex vivo. In vivo treatment efficacy was tested in a murine model. The rhabdovirus MG1 demonstrated the highest potency in vitro. Ex vivo, MG1 productively infected more than 80% of human sarcoma tissues tested, and treatment in vivo led to a significant increase in long-lasting cures in sarcoma-bearing mice. Importantly, MG1 treatment induced the generation of memory immune response that provided protection against a subsequent tumor challenge. This study opens the door for the use of MG1-based oncolytic immunotherapy strategies as treatment for sarcoma or as a component of a combined therapy.


Assuntos
Terapia Viral Oncolítica/métodos , Rhabdoviridae/fisiologia , Sarcoma/terapia , Sarcoma/virologia , Animais , Neoplasias Ósseas/terapia , Neoplasias Ósseas/virologia , Linhagem Celular Tumoral , Cães , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Osteossarcoma/terapia , Osteossarcoma/virologia , Sarcoma de Ewing/terapia , Sarcoma de Ewing/virologia , Sarcoma Sinovial/terapia , Sarcoma Sinovial/virologia
8.
J Clin Invest ; 125(2): 752-68, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25562320

RESUMO

The phagocytosis of apoptotic cells and associated vesicles (efferocytosis) by DCs is an important mechanism for both self tolerance and host defense. Although some of the engulfment ligands involved in efferocytosis have been identified and studied in vitro, the contributions of these ligands in vivo remain ill defined. Here, we determined that during Mycobacterium tuberculosis (Mtb) infection, the engulfment ligand annexin1 is an important mediator in DC cross-presentation that increases efferocytosis in DCs and intrinsically enhances the capacity of the DC antigen-presenting machinery. Annexin1-deficient mice were highly susceptible to Mtb infection and showed an impaired Mtb antigen-specific CD8+ T cell response. Importantly, annexin1 expression was greatly downregulated in Mtb-infected human blood monocyte-derived DCs, indicating that reduction of annexin1 is a critical mechanism for immune evasion by Mtb. Collectively, these data indicate that annexin1 is essential in immunity to Mtb infection and mediates the power of DC efferocytosis and cross-presentation.


Assuntos
Anexina A1/imunologia , Apresentação Cruzada , Células Dendríticas/imunologia , Imunidade Celular , Mycobacterium tuberculosis/imunologia , Fagocitose , Tuberculose/imunologia , Animais , Anexina A1/genética , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Células Dendríticas/patologia , Humanos , Camundongos , Camundongos Knockout , Monócitos/imunologia , Monócitos/patologia , Tuberculose/genética , Tuberculose/patologia
9.
Proc Natl Acad Sci U S A ; 111(20): E2110-9, 2014 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-24799673

RESUMO

To subvert host immunity, influenza A virus (IAV) induces early apoptosis in innate immune cells by disrupting mitochondria membrane potential via its polymerase basic protein 1-frame 2 (PB1-F2) accessory protein. Whether immune cells have mechanisms to counteract PB1-F2-mediated apoptosis is currently unknown. Herein, we define that the host mitochondrial protein nucleotide-binding oligomerization domain-like receptor (NLR)X1 binds to viral protein PB1-F2, preventing IAV-induced macrophage apoptosis and promoting both macrophage survival and type I IFN signaling. We initially observed that Nlrx1-deficient mice infected with IAV exhibited increased pulmonary viral replication, as well as enhanced inflammatory-associated pulmonary dysfunction and morbidity. Analysis of the lungs of IAV-infected mice revealed markedly enhanced leukocyte recruitment but impaired production of type I IFN in Nlrx1(-/-) mice. Impaired type I IFN production and enhanced viral replication was recapitulated in Nlrx1(-/-) macrophages and was associated with increased mitochondrial mediated apoptosis. Through gain- and loss-of-function strategies for protein interaction, we identified that NLRX1 directly bound PB1-F2 in the mitochondria of macrophages. Using a recombinant virus lacking PB1-F2, we confirmed that deletion of PB1-F2 abrogated NLRX1-dependent macrophage type I IFN production and apoptosis. Thus, our results demonstrate that NLRX1 acts as a mitochondrial sentinel protecting macrophages from PB1-F2-induced apoptosis and preserving their antiviral function. We further propose that NLRX1 is critical for macrophage immunity against IAV infection by sensing the extent of viral replication and maintaining a protective balance between antiviral immunity and excessive inflammation within the lungs.


Assuntos
Apoptose , Vírus da Influenza A/imunologia , Macrófagos/imunologia , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Proteínas Virais/metabolismo , Animais , Linhagem Celular Tumoral , Humanos , Inflamação , Vírus da Influenza A/fisiologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Mitocondriais/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Replicação Viral
10.
Immunity ; 40(4): 554-68, 2014 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-24726877

RESUMO

Aspirin gained tremendous popularity during the 1918 Spanish Influenza virus pandemic, 50 years prior to the demonstration of their inhibitory action on prostaglandins. Here, we show that during influenza A virus (IAV) infection, prostaglandin E2 (PGE2) was upregulated, which led to the inhibition of type I interferon (IFN) production and apoptosis in macrophages, thereby causing an increase in virus replication. This inhibitory role of PGE2 was not limited to innate immunity, because both antigen presentation and T cell mediated immunity were also suppressed. Targeted PGE2 suppression via genetic ablation of microsomal prostaglandin E-synthase 1 (mPGES-1) or by the pharmacological inhibition of PGE2 receptors EP2 and EP4 substantially improved survival against lethal IAV infection whereas PGE2 administration reversed this phenotype. These data demonstrate that the mPGES-1-PGE2 pathway is targeted by IAV to evade host type I IFN-dependent antiviral immunity. We propose that specific inhibition of PGE2 signaling might serve as a treatment for IAV.


Assuntos
Dinoprostona/metabolismo , Vírus da Influenza A/fisiologia , Interferon Tipo I/metabolismo , Oxirredutases Intramoleculares/antagonistas & inibidores , Macrófagos/efeitos dos fármacos , Infecções por Orthomyxoviridae/tratamento farmacológico , Animais , Apresentação de Antígeno/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Células Cultivadas , Dinoprostona/imunologia , Regulação da Expressão Gênica/efeitos dos fármacos , Imunidade/efeitos dos fármacos , Imunidade/genética , Interferon Tipo I/genética , Oxirredutases Intramoleculares/genética , Macrófagos/imunologia , Macrófagos/virologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Terapia de Alvo Molecular , Infecções por Orthomyxoviridae/imunologia , Prostaglandina-E Sintases , Receptores de Prostaglandina E Subtipo EP2/antagonistas & inibidores , Receptores de Prostaglandina E Subtipo EP4/antagonistas & inibidores , Linfócitos T/imunologia , Linfócitos T/virologia , Replicação Viral/genética
11.
J Immunol ; 190(3): 1066-75, 2013 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-23277488

RESUMO

CD8(+) T cells undergo rapid expansion during infection with intracellular pathogens, which is followed by swift and massive culling of primed CD8(+) T cells. The mechanisms that govern the massive contraction and maintenance of primed CD8(+) T cells are not clear. We show in this study that the transcription factor, FoxO3a, does not influence Ag presentation and the consequent expansion of CD8(+) T cell response during Listeria monocytogenes infection, but plays a key role in the maintenance of memory CD8(+) T cells. The effector function of primed CD8(+) T cells as revealed by cytokine secretion and CD107a degranulation was not influenced by inactivation of FoxO3a. Interestingly, FoxO3a-deficient CD8(+) T cells displayed reduced expression of proapoptotic molecules BIM and PUMA during the various phases of response, and underwent reduced apoptosis in comparison with wild-type cells. A higher number of memory precursor effector cells and memory subsets was detectable in FoxO3a-deficient mice compared with wild-type mice. Furthermore, FoxO3a-deficient memory CD8(+) T cells upon transfer into normal or RAG1-deficient mice displayed enhanced survival. These results suggest that FoxO3a acts in a cell-intrinsic manner to regulate the survival of primed CD8(+) T cells.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Fatores de Transcrição Forkhead/imunologia , Memória Imunológica/imunologia , Listeriose/imunologia , Ativação Linfocitária/imunologia , Subpopulações de Linfócitos/imunologia , Animais , Apresentação de Antígeno , Antígenos de Bactérias/imunologia , Apoptose/imunologia , Proteínas Reguladoras de Apoptose/biossíntese , Proteínas Reguladoras de Apoptose/genética , Proteína 11 Semelhante a Bcl-2 , Linfócitos T CD8-Positivos/metabolismo , Citocinas/sangue , Citotoxicidade Imunológica , Feminino , Proteína Forkhead Box O3 , Fatores de Transcrição Forkhead/deficiência , Proteínas de Homeodomínio/genética , Selectina L/biossíntese , Selectina L/genética , Listeria monocytogenes/imunologia , Listeriose/sangue , Subpopulações de Linfócitos/metabolismo , Linfocinas/metabolismo , Glicoproteínas de Membrana Associadas ao Lisossomo/imunologia , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina/genética , Ovalbumina/imunologia , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , Receptores de Interleucina-7/biossíntese , Receptores de Interleucina-7/genética , Proteínas Supressoras de Tumor/biossíntese , Proteínas Supressoras de Tumor/genética
12.
Cell Rep ; 2(6): 1710-21, 2012 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-23219554

RESUMO

Pathogens that reside in the phagosomes of infected cells persist despite the presence of potent T cell responses. We addressed the mechanism of immune evasion by using a mouse model of Salmonella typhimurium (ST). Recombinants of ST were generated that translocated antigen to the cytosol or phagosomes of infected cells. We find that the kinetics of antigen presentation and CD8(+) T cell priming is accelerated by cytosolic antigen delivery, although the magnitude of CD8(+) T cell response is not influenced by antigenic location. More importantly, only those targets that readily display antigen on the cell surface, owing to antigenic translocation to the cytosol, are recognized and killed by CD8(+) T cells. Thus, vaccination approaches developed to control phagosomal pathogens should incorporate methods for modulating antigen presentation such that infected target cells can be readily recognized by CD8(+) T cells.


Assuntos
Apresentação de Antígeno , Antígenos de Bactérias/imunologia , Linfócitos T CD8-Positivos/imunologia , Imunidade Celular , Infecções por Salmonella/imunologia , Salmonella typhimurium/imunologia , Doença Aguda , Animais , Antígenos de Bactérias/genética , Linfócitos T CD8-Positivos/patologia , Doença Crônica , Camundongos , Camundongos Transgênicos , Infecções por Salmonella/genética , Infecções por Salmonella/patologia , Salmonella typhimurium/genética
13.
PLoS Pathog ; 6(4): e1000870, 2010 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-20442858

RESUMO

The murine model of T. cruzi infection has provided compelling evidence that development of host resistance against intracellular protozoans critically depends on the activation of members of the Toll-like receptor (TLR) family via the MyD88 adaptor molecule. However, the possibility that TLR/MyD88 signaling pathways also control the induction of immunoprotective CD8+ T cell-mediated effector functions has not been investigated to date. We addressed this question by measuring the frequencies of IFN-gamma secreting CD8+ T cells specific for H-2K(b)-restricted immunodominant peptides as well as the in vivo Ag-specific cytotoxic response in infected animals that are deficient either in TLR2, TLR4, TLR9 or MyD88 signaling pathways. Strikingly, we found that T. cruzi-infected Tlr2(-/-), Tlr4(-/-), Tlr9(-/) (-) or Myd88(-/-) mice generated both specific cytotoxic responses and IFN-gamma secreting CD8+ T cells at levels comparable to WT mice, although the frequency of IFN-gamma+CD4+ cells was diminished in infected Myd88(-/-) mice. We also analyzed the efficiency of TLR4-driven immune responses against T. cruzi using TLR4-deficient mice on the C57BL genetic background (B6 and B10). Our studies demonstrated that TLR4 signaling is required for optimal production of IFN-gamma, TNF-alpha and nitric oxide (NO) in the spleen of infected animals and, as a consequence, Tlr4(-/-) mice display higher parasitemia levels. Collectively, our results indicate that TLR4, as well as previously shown for TLR2, TLR9 and MyD88, contributes to the innate immune response and, consequently, resistance in the acute phase of infection, although each of these pathways is not individually essential for the generation of class I-restricted responses against T. cruzi.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Doença de Chagas/imunologia , Imunidade Inata , Transdução de Sinais/imunologia , Receptor 4 Toll-Like/imunologia , Animais , Doença de Chagas/genética , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/deficiência , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/imunologia , Óxido Nítrico Sintase Tipo II/imunologia , Óxido Nítrico Sintase Tipo II/metabolismo , Receptor 2 Toll-Like/deficiência , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/imunologia , Receptor 4 Toll-Like/deficiência , Receptor 4 Toll-Like/genética , Receptor Toll-Like 9/deficiência , Receptor Toll-Like 9/genética , Receptor Toll-Like 9/imunologia , Trypanosoma cruzi/imunologia
14.
Mem Inst Oswaldo Cruz ; 104 Suppl 1: 281-7, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19753486

RESUMO

Vaccines have had an unquestionable impact on public health during the last century. The most likely reason for the success of vaccines is the robust protective properties of specific antibodies. However, antibodies exert a strong selective pressure and many microorganisms, such as the obligatory intracellular parasite Trypanosoma cruzi, have been selected to survive in their presence. Although the host develops a strong immune response to T. cruzi, they do not clear the infection and instead progress to the chronic phase of the disease. Parasite persistence during the chronic phase of infection is now considered the main factor contributing to the chronic symptoms of the disease. Based on this finding, containment of parasite growth and survival may be one method to avoid the immunopathology of the chronic phase. In this context, vaccinologists have looked over the past 20 years for other immune effector mechanisms that could eliminate these antibody-resistant pathogens. We and others have tested the hypothesis that non-antibody-mediated cellular immune responses (CD4+ Th1 and CD8+ Tc1 cells) to specific parasite antigens/genes expressed by T. cruzi could indeed be used for the purpose of vaccination. This hypothesis was confirmed in different mouse models, indicating a possible path for vaccine development.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Doença de Chagas/imunologia , Vacinas Protozoárias/imunologia , Trypanosoma cruzi/imunologia , Animais , Antígenos de Protozoários/genética , Antígenos de Protozoários/imunologia , Doença de Chagas/prevenção & controle , Modelos Animais de Doenças , Imunidade Celular , Camundongos , Trypanosoma cruzi/genética
15.
Vaccine ; 27(41): 5644-53, 2009 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-19635607

RESUMO

Immunisation with Amastigote Surface Protein 2 (asp-2) and trans-sialidase (ts) genes induces protective immunity in highly susceptible A/Sn mice, against infection with parasites of the Y strain of Trypanosoma cruzi. Based on immunological and biological strain variations in T. cruzi parasites, our goal was to validate our vaccination results using different parasite strains. Due to the importance of the CD8(+) T cells in protective immunity, we initially determined which strains expressed the immunodominant H-2K(k)-restricted epitope TEWETGQI. We tested eight strains, four of which elicited immune responses to this epitope (Y, G, Colombian and Colombia). We selected the Colombian and Colombia strains for our studies. A/Sn mice were immunised with different regimens using both T. cruzi genes (asp-2 and ts) simultaneously and subsequently challenged with blood trypomastigotes. Immune responses before the challenge were confirmed by the presence of specific antibodies and peptide-specific T cells. Genetic vaccination did not confer protective immunity against acute infection with a lethal dose of the Colombian strain. In contrast, we observed a drastic reduction in parasitemia and a significant increase in survival, following challenge with an otherwise lethal dose of the Colombia strain. In many surviving animals with late-stage chronic infection, we observed alterations in the heart's electrical conductivity, compared to naive mice. In summary, we concluded that immunity against T. cruzi antigens, similar to viruses and bacteria, may be strain-specific and have a negative impact on vaccine development.


Assuntos
Doença de Chagas/prevenção & controle , Glicoproteínas/imunologia , Neuraminidase/imunologia , Vacinas Protozoárias/imunologia , Trypanosoma cruzi/imunologia , Vacinas de DNA/imunologia , Animais , Anticorpos Antiprotozoários/sangue , Sequência de Bases , Reações Cruzadas , Epitopos de Linfócito T/imunologia , Feminino , Humanos , Camundongos , Dados de Sequência Molecular , Parasitemia/prevenção & controle , Alinhamento de Sequência , Análise de Sobrevida , Linfócitos T/imunologia
16.
Mem. Inst. Oswaldo Cruz ; 104(supl.1): 281-287, July 2009. tab
Artigo em Inglês | LILACS | ID: lil-520890

RESUMO

Vaccines have had an unquestionable impact on public health during the last century. The most likely reason for the success of vaccines is the robust protective properties of specific antibodies. However, antibodies exert a strong selective pressure and many microorganisms, such as the obligatory intracellular parasite Trypanosoma cruzi, have been selected to survive in their presence. Although the host develops a strong immune response to T. cruzi, they do not clear the infection and instead progress to the chronic phase of the disease. Parasite persistence during the chronic phase of infection is now considered the main factor contributing to the chronic symptoms of the disease. Based on this finding, containment of parasite growth and survival may be one method to avoid the immunopathology of the chronic phase. In this context, vaccinologists have looked over the past 20 years for other immune effector mechanisms that could eliminate these antibody-resistant pathogens. We and others have tested the hypothesis that non-antibody-mediated cellular immune responses (CD4+ Th1 and CD8+ Tc1 cells) to specific parasite antigens/genes expressed by T. cruzi could indeed be used for the purpose of vaccination. This hypothesis was confirmed in different mouse models, indicating a possible path for vaccine development.


Assuntos
Animais , Camundongos , /imunologia , /imunologia , Doença de Chagas/imunologia , Vacinas Protozoárias/imunologia , Trypanosoma cruzi/imunologia , Antígenos de Protozoários/genética , Antígenos de Protozoários/imunologia , Doença de Chagas/prevenção & controle , Modelos Animais de Doenças , Imunidade Celular , Trypanosoma cruzi/genética
17.
Transpl Immunol ; 21(1): 50-5, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19233269

RESUMO

Ischemia reperfusion injury (IRI) is a potential contributor for the development of chronic allograft nephropathy. T cells are important mediators of injury, even in the absence of alloantigens. We performed a depletion of TCD4(+)CTLA4(+)Foxp3(+) cells with anti-CD25(PC61), a treatment with anti-GITR (DTA-1) and rat-IgG, followed by 45 min of ischemia and 24/72 h of reperfusion, and then analyzed blood urea, kidney histopathology and gene expression in kidneys by QReal Time PCR. After 24 h of reperfusion, depletion of TCD4(+)CTLA4(+)Foxp3(+) cells reached 30.3%(spleen) and 67.8%(lymph nodes). 72 h after reperfusion depletion reached 43.1%(spleen) and 90.22%(lymph nodes) and depleted animals presented with significantly poorer renal function, while DTA-1(anti-GITR)-treated ones showed a significant protection, all compared to serum urea from control group (IgG: 150.10+/-50.04; PC61: 187.23+/-31.38; DTA-1: 64.53+/-25.65, mg/dL, p<0.05). These data were corroborated by histopathology. We observed an increase of HO-1 expression in animals treated with DTA-1 at 72 h of reperfusion with significant differences. Thus, our results suggest that PC61(anti-CD25) mAb treatment is deleterious, while DTA-1(anti-GITR) mAb treatment presents a protective role in the renal IRI, indicating that some regulatory populations of T cells might have a role in IRI.


Assuntos
Injúria Renal Aguda/imunologia , Traumatismo por Reperfusão/imunologia , Linfócitos T Reguladores/imunologia , Injúria Renal Aguda/genética , Injúria Renal Aguda/patologia , Animais , Nitrogênio da Ureia Sanguínea , Citometria de Fluxo , Fatores de Transcrição Forkhead/biossíntese , Fatores de Transcrição Forkhead/genética , Expressão Gênica , Heme Oxigenase-1/biossíntese , Heme Oxigenase-1/genética , Rim/imunologia , Rim/lesões , Rim/patologia , Depleção Linfocítica/métodos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Antígeno Nuclear de Célula em Proliferação/biossíntese , Antígeno Nuclear de Célula em Proliferação/genética , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa
18.
J Immunol ; 180(3): 1737-48, 2008 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-18209071

RESUMO

Interference or competition between CD8(+) T cells restricted by distinct MHC-I molecules can be a powerful means to establish an immunodominant response. However, its importance during infections is still questionable. In this study, we describe that following infection of mice with the human pathogen Trypanosoma cruzi, an immunodominant CD8(+) T cell immune response is developed directed to an H-2K(b)-restricted epitope expressed by members of the trans-sialidase family of surface proteins. To determine whether this immunodominance was exerted over other non-H-2K(b)-restricted epitopes, we measured during infection of heterozygote mice, immune responses to three distinct epitopes, all expressed by members of the trans-sialidase family, recognized by H-2K(b)-, H-2K(k)-, or H-2K(d)-restricted CD8(+) T cells. Infected heterozygote or homozygote mice displayed comparably strong immune responses to the H-2K(b)-restricted immunodominant epitope. In contrast, H-2K(k)- or H-2K(d)-restricted immune responses were significantly impaired in heterozygote infected mice when compared with homozygote ones. This interference was not dependent on the dose of parasite or the timing of infection. Also, it was not seen in heterozygote mice immunized with recombinant adenoviruses expressing T. cruzi Ags. Finally, we observed that the immunodominance was circumvented by concomitant infection with two T. cruzi strains containing distinct immunodominant epitopes, suggesting that the operating mechanism most likely involves competition of T cells for limiting APCs. This type of interference never described during infection with a human parasite may represent a sophisticated strategy to restrict priming of CD8(+) T cells of distinct specificities, avoiding complete pathogen elimination by host effector cells, and thus favoring host parasitism.


Assuntos
Antígenos de Protozoários/imunologia , Linfócitos T CD8-Positivos/imunologia , Doença de Chagas/imunologia , Antígenos H-2/imunologia , Epitopos Imunodominantes/imunologia , Trypanosoma cruzi/imunologia , Adenoviridae/genética , Sequência de Aminoácidos , Animais , Apresentação de Antígeno , Células Apresentadoras de Antígenos/imunologia , Antígenos H-2/química , Antígenos H-2/genética , Heterozigoto , Imunização , Camundongos , Camundongos Endogâmicos , Dados de Sequência Molecular
19.
Vaccine ; 25(32): 6007-17, 2007 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-17629370

RESUMO

Synthetic oligonucleotides (ODNs) containing immunostimulatory CpG motifs (CpG) are a new class of adjuvants suitable for the development of recombinant vaccines. Here we describe that endogenous interferon (IFN) was critical for the adjuvant activity of CpG ODN as genetically deficient mice developed significantly lower IgG antibody titers following immunization with recombinant proteins. In contrast, the absence of endogenous IL-12/IL-23 or IL-4 had little impact on the magnitude of the antibody response but instead caused a dramatic change in the pattern of IgG isotypes. The dependence on IFN-gamma was specific for CpG ODN and it was not observed with other adjuvants tested. IFN-gamma was produced by NK, dendritic cells, CD4+ and CD8+ T cells stimulated in vitro with CpG ODN. Adoptive transfer experiments confirmed that CD4+ or CD8+ T cells were in fact relevant sources of IFN-gamma in vivo. Following CpG ODN injection, splenic dendritic cells from IFN-gamma deficient mice did not up-regulate CD86 or CD40 expression, suggesting a role for these molecules. The importance of CD28 (CD86 ligand) was confirmed using CD28 deficient mice which presented severely impaired immune responses following CpG ODN-assisted immunization.


Assuntos
Adjuvantes Imunológicos , Ilhas de CpG/imunologia , Interferon gama/imunologia , Proteínas Recombinantes/imunologia , Animais , Antígenos CD28/genética , Antígenos CD28/imunologia , Antígenos CD28/metabolismo , Ilhas de CpG/genética , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Epitopos/imunologia , Feminino , Deleção de Genes , Imunoglobulina G/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Camundongos , Baço/citologia , Baço/imunologia , Linfócitos T/imunologia
20.
PLoS One ; 2(4): e393, 2007 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-17460760

RESUMO

BACKGROUND: Following infection with viruses, bacteria or protozoan parasites, naïve antigen-specific CD8(+) T cells undergo a process of differentiation and proliferation to generate effector cells. Recent evidences suggest that the timing of generation of specific effector CD8(+) T cells varies widely according to different pathogens. We hypothesized that the timing of increase in the pathogen load could be a critical parameter governing this process. METHODOLOGY/PRINCIPAL FINDINGS: Using increasing doses of the protozoan parasite Trypanosoma cruzi to infect C57BL/6 mice, we observed a significant acceleration in the timing of parasitemia without an increase in mouse susceptibility. In contrast, in CD8 deficient mice, we observed an inverse relationship between the parasite inoculum and the timing of death. These results suggest that in normal mice CD8(+) T cells became protective earlier, following the accelerated development of parasitemia. The evaluation of specific cytotoxic responses in vivo to three distinct epitopes revealed that increasing the parasite inoculum hastened the expansion of specific CD8(+) cytotoxic T cells following infection. The differentiation and expansion of T. cruzi-specific CD8(+) cytotoxic T cells is in fact dependent on parasite multiplication, as radiation-attenuated parasites were unable to activate these cells. We also observed that, in contrast to most pathogens, the activation process of T. cruzi-specific CD8(+) cytotoxic T cells was dependent on MHC class II restricted CD4(+) T cells. CONCLUSIONS/SIGNIFICANCE: Our results are compatible with our initial hypothesis that the timing of increase in the pathogen load can be a critical parameter governing the kinetics of CD4(+) T cell-dependent expansion of pathogen-specific CD8(+) cytotoxic T cells.


Assuntos
Linfócitos T CD4-Positivos/citologia , Linfócitos T CD8-Positivos/citologia , Diferenciação Celular , Proliferação de Células , Trypanosoma cruzi/fisiologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos C57BL
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