RESUMO
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.
Assuntos
Animais , Masculino , Camundongos , Linfócitos B/imunologia , Proteínas de Choque Térmico/imunologia , Imunomodulação/genética , /genética , RNA Mensageiro/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos B/metabolismo , Citometria de Fluxo , Expressão Gênica/genética , Proteínas de Choque Térmico/uso terapêutico , Memória Imunológica/fisiologia , Imunofenotipagem/classificação , Mediadores da Inflamação/análise , Interferon gama/análise , /imunologia , /análise , Camundongos Knockout , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , RNA Mensageiro/genética , Baço/citologia , Baço/imunologia , Subpopulações de Linfócitos T/classificação , Vacinas de DNA/imunologia , Vacinas de DNA/uso terapêuticoRESUMO
Over the past twenty years, many authors have reported evidence of the immunoprotective capacity of ribosomes isolated from bacteria, fungi and parasites. Since 1971 we have explored the protective capacity of ribosomes isolated from a large variety of microorganisms responsible for human and animal diseases. More recently, using monoclonal antibodies raised against ribosomes and then selected for their ability to confer passive immunity to mice, we have studied the mechanism of the protection induced by ribosomes. These studies, in parallel with the development of a technology for the large scale production of ribosomes, have allowed us to achieve a new regard for ribosomal vaccines for use in human. The general concept of ribosomal vaccines in presented and examples of two such vaccines are described with data on the specific protection that they induce in mice against experimental infections with Klebsiella peneumoniae, Streptococcus pneumoniae, S. pyogenes and Haemophilus influenzae for the first one, and against Candida albicans type A and type B for the second one. Because of their high immunogenicity and their innocuity these vaccines represent a decisive improvement over classical microbial vaccines.