ABSTRACT
In DNA vaccines, the gene of interest is cloned into a bacterial plasmid that is engineered to induce protein production for long periods in eukaryotic cells. Previous research has shown that the intramuscular immunization of BALB/c mice with a naked plasmid DNA fragment encoding the Mycobacterium leprae 65-kDa heat-shock protein (pcDNA3-Hsp65) induces protection against M. tuberculosis challenge. A key stage in the protective immune response after immunization is the generation of memory T cells. Previously, we have shown that B cells capture plasmid DNA-Hsp65 and thereby modulate the formation of CD8+ memory T cells after M. tuberculosis challenge in mice. Therefore, clarifying how B cells act as part of the protective immune response after DNA immunization is important for the development of more-effective vaccines. The aim of this study was to investigate the mechanisms by which B cells modulate memory T cells after DNA-Hsp65 immunization. C57BL/6 and BKO mice were injected three times, at 15-day intervals, with 100 µg naked pcDNA-Hsp65 per mouse. Thirty days after immunization, the percentages of effector memory T (TEM) cells (CD4+ and CD8+/CD44high/CD62Llow) and memory CD8+ T cells (CD8+/CD44high/CD62Llow/CD127+) were measured with flow cytometry. Interferon γ, interleukin 12 (IL-12), and IL-10 mRNAs were also quantified in whole spleen cells and purified B cells (CD43−) with real-time qPCR. Our data suggest that a B-cell subpopulation expressing IL-10 downregulated proinflammatory cytokine expression in the spleen, increasing the survival of CD4+ TEM cells and CD8+ TEM/CD127+ cells.
Subject(s)
Animals , Male , Mice , B-Lymphocytes/immunology , Heat-Shock Proteins/immunology , Immunomodulation/genetics , /genetics , RNA, Messenger/immunology , T-Lymphocyte Subsets/immunology , B-Lymphocytes/metabolism , Flow Cytometry , Gene Expression/genetics , Heat-Shock Proteins/therapeutic use , Immunologic Memory/physiology , Immunophenotyping/classification , Inflammation Mediators/analysis , Interferon-gamma/analysis , /immunology , /analysis , Mice, Knockout , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , RNA, Messenger/genetics , Spleen/cytology , Spleen/immunology , T-Lymphocyte Subsets/classification , Vaccines, DNA/immunology , Vaccines, DNA/therapeutic useABSTRACT
In the last several years, the use of dendritic cells has been studied as a therapeutic strategy against tumors. Dendritic cells can be pulsed with peptides or full-length protein, or they can be transfected with DNA or RNA. However, comparative studies suggest that transfecting dendritic cells with messenger RNA (mRNA) is superior to other antigen-loading techniques in generating immunocompetent dendritic cells. In the present study, we evaluated a new therapeutic strategy to fight tuberculosis using dendritic cells and macrophages transfected with Hsp65 mRNA. First, we demonstrated that antigen-presenting cells transfected with Hsp65 mRNA exhibit a higher level of expression of co-stimulatory molecules, suggesting that Hsp65 mRNA has immunostimulatory properties. We also demonstrated that spleen cells obtained from animals immunized with mock and Hsp65 mRNA-transfected dendritic cells were able to generate a mixed Th1/Th2 response with production not only of IFN-γ but also of IL-5 and IL-10. In contrast, cells recovered from mice immunized with Hsp65 mRNA-transfected macrophages were able to produce only IL-5. When mice were infected with Mycobacterium tuberculosis and treated with antigen-presenting cells transfected with Hsp65 mRNA (therapeutic immunization), we did not detect any decrease in the lung bacterial load or any preservation of the lung parenchyma, indicating the inability of transfected cells to confer curative effects against tuberculosis. In spite of the lack of therapeutic efficacy, this study reports for the first time the use of antigen-presenting cells transfected with mRNA in experimental tuberculosis.
Subject(s)
Animals , Male , Mice , Antigen-Presenting Cells/immunology , Bacterial Proteins/administration & dosage , /administration & dosage , Mycobacterium tuberculosis/immunology , RNA, Messenger/immunology , Tuberculosis Vaccines/administration & dosage , Tuberculosis/immunology , Bacterial Proteins/adverse effects , Bacterial Proteins/immunology , /adverse effects , /immunology , Mice, Inbred BALB C , RNA, Messenger/adverse effects , Spleen/immunology , Transfection , Tuberculosis Vaccines/adverse effects , Tuberculosis Vaccines/immunology , Tuberculosis/prevention & controlABSTRACT
O tratamento da trombose portal congênita é controverso, entretanto, a tendência é de que as varizes esofageanas sejam tratadas por esclerose endoscópica e a hipertensÝo porta seja manuseada por desvios porto-sistêmicos. alternativamente, esplenectomia e desvascularizaçÝo esôfago-gástrica têm sido usadas, com índice de recidiva hemorrágica significativa. A embolizaçÝo eplênica parcial tem sido feita, em alguns casos, como forma de tratamento efetivo do hiperesplenismo. Três casos de crianças portadoras de trombose portal congênita foram tratadas nos últimos três anos no Serviço de cirurgia Geral da Criança do Hospital das clínicas da UFPE. Os dois primeiros pacientes, um do sexo masculino e o outro do sexo feminino, com seis e oito anos de idades, respectivamente, foram tratados por esplenectomia, desvascularizaçÝo esôfao-gástrica e esclerose endoscópoca das varizes esofageanas. Um dos pacientes apresentou recidiva hemorrágica apoós dois anos de seguimento, tendo sido controlado por escleroterapia endoscópica das varizes esofageanas. O caso mais recente, de uma criança do sexo masculino, doze anos de idade, está sendo tratado com esclerse endoscópica das varizes esofageanas, embolizaçÝo de cerca de 80 porcento do baço e desvascularizaçÝo esôfago-gástrica, por via veolaparoscópica. essa abordagem fez desaparecer as varizes esofageanas do último paciente e está sendo proposta como modelo de protocolo para os casos futuros