Protection conferred by heterologous vaccination against tuberculosis is dependent on the ratio of CD4+/CD4+ Foxp3+ cells

Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
Immunology (Impact Factor: 3.8). 08/2012; 137(3):239-48. DOI: 10.1111/imm.12006
Source: PubMed


CD4(+) Foxp3(+) regulatory T cells inhibit the production of interferon-γ, which is the major mediator of protection against Mycobacterium tuberculosis infection. In this study, we evaluated whether the protection conferred by three different vaccines against tuberculosis was associated with the number of spleen and lung regulatory T cells. We observed that after homologous immunization with the 65 000 molecular weight heat-shock protein (hsp 65) DNA vaccine, there was a significantly higher number of spleen CD4(+) Foxp3(+) cells compared with non-immunized mice. Heterologous immunization using bacillus Calmette-Guérin (BCG) to prime and DNA-hsp 65 to boost (BCG/DNA-hsp 65) or BCG to prime and culture filtrate proteins (CFP)-CpG to boost (BCG/CFP-CpG) induced a significantly higher ratio of spleen CD4(+) /CD4(+) Foxp3(+) cells compared with non-immunized mice. In addition, the protection conferred by either the BCG/DNA-hsp 65 or the BCG/CFP-CpG vaccines was significant compared with the DNA-hsp 65 vaccine. Despite the higher ratio of spleen CD4(+) /CD4(+) Foxp3(+) cells found in BCG/DNA-hsp 65-immunized or BCG/CFP-CpG-immunized mice, the lungs of both groups of mice were better preserved than those of DNA-hsp 65-immunized mice. These results confirm the protective efficacy of BCG/DNA-hsp 65 and BCG/CFP-CpG heterologous prime-boost vaccines and the DNA-hsp 65 homologous vaccine. Additionally, the prime-boost regimens assayed here represent a promising strategy for the development of new vaccines to protect against tuberculosis because they probably induce a proper ratio of CD4(+) and regulatory (CD4(+) Foxp3(+) ) cells during the immunization regimen. In this study, this ratio was associated with a reduced number of regulatory cells and no injury to the lungs.

Download full-text


Available from: Celio L Silva
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite the enormous efforts displayed globally in the fight against tuberculosis, the disease incidence has modified slightly, which has led to a renewed interest in immunotherapy. In general, successful immunotherapeutic candidates against tuberculosis are agents that can trigger strong, specific pro-inflammatory responses, especially of the T-helper (Th) 1 pattern. However, how these pro-inflammatory agents effectively kill the bacteria without eliciting immunopathology is not well understood. We reasoned that, in addition to the specific immune response elicited by immunotherapy, the evaluation of the overall pro-inflammatory responses should provide additional and valuable information that will be useful in avoiding immunopathology. We evaluated the overall IFN-γ and IL-17 pro-inflammatory responses among CD4 (+) , CD8 (+) and γδ T cells in the lungs of mice that were infected with M. tuberculosis and treated with a DNA vaccine in an immunotherapeutic regimen. Our results demonstrate that mice that effectively combat the pathogen develop a strong, specific Th1 immune response against the therapeutic antigen and have reduced lung inflammation, present in parallel a fine-tuning in the total IFN-γ- and IL-17-mediated immunity in the lungs. This modulation of the total immune response involves reducing the Th17 cell population, augmenting CD8 (+) T cells that produce IFN-γ and increasing the total γδ T cell frequency. These results stress the importance of a broad evaluation of not only the specific immune response at the time to evaluate new immune interventional strategies against tuberculosis but also non-conventional T cells, such as γδ T lymphocytes.
    Full-text · Article · Jan 2013 · Human Vaccines & Immunotherapeutics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tuberculosis (TB) is a serious public health problem. Development of experimental models and vaccines are essential to elucidate physiopathological mechanisms and to control the disease. Vascular endothelial growth factor (VEGF) is a potent activator of vascular permeability and angiogenesis. VEGF seems to participate in breakdown of the blood brain-barrier (BBB) in tuberculous meningitis (TBM), contributing to worsening of disease. Therefore, the objective here was to extent the characterization of our previously described murine model of central nervous system TB (CNS-TB) by describing the VEGF participation in the CNS disease, and suggesting a vaccination plan in mice. Plasmid encoding DNA protein antigen DNA-hsp65 has been described as a protector against TB infection and was used here to test its effectiveness in the prevention of VEGF production and TB disease. Vaccinated mice and its controls were injected with Mycobacterium bovis bacillus Calmette-Guerin (BCG) in cerebellum. Four weeks after BCG injection, mice were perfused and brains were paraffin-embedded for VEGF expression analysis. We observed VEGF immunohistochemical expression in TBM and granulomas in non-vaccinated mice. The DNA-hsp65 treatment blocked the expression of VEGF in mice TBM. Therefore, our murine model indicated the VEGF participation in the physiopathology of CNS-TB and the potential prevention of the DNA-hsp65 in the disease progression.
    Full-text · Article · Mar 2013 · Tuberculosis (Edinburgh, Scotland)
  • [Show abstract] [Hide abstract]
    ABSTRACT: We previously showed that, in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease (PD), vaccination with bacillus Calmette-Guerin (BCG) prior to MPTP exposure limited the loss of striatal dopamine (DA) and dopamine transporter (DAT) and prevented the activation of nigral microglia. Here, we conducted BCG dose studies and investigated the mechanisms underlying BCG vaccination's neuroprotective effects in this model. We found that a dose of 1 × 10(6) cfu BCG led to higher levels of striatal DA and DAT ligand binding (28% and 42%, respectively) in BCG-vaccinated vs. unvaccinated MPTP-treated mice, but without a significant increase in substantia nigra tyrosine hydroxylase-staining neurons. Previous studies showed that BCG can induce regulatory T cells (Tregs) and that Tregs are neuroprotective in models of neurodegenerative diseases. However, MPTP is lymphotoxic, so it was unclear whether Tregs were maintained after MPTP treatment and whether a relationship existed between Tregs and the preservation of striatal DA system integrity. We found that, 21 days post-MPTP treatment, Treg levels in mice that had received BCG prior to MPTP were threefold greater than those in MPTP-only-treated mice and elevated above those in saline-only-treated mice, suggesting that the persistent BCG infection continually promoted Treg responses. Notably, the magnitude of the Treg response correlated positively with both striatal DA levels and DAT ligand binding. Therefore, BCG vaccine-mediated neuroprotection is associated with Treg levels in this mouse model. Our results suggest that BCG-induced Tregs could provide a new adjunctive therapeutic approach to ameliorating pathology associated with PD and other neurodegenerative diseases. © 2013 Wiley Periodicals, Inc.
    No preview · Article · Oct 2013 · Journal of Neuroscience Research
Show more

We use cookies to give you the best possible experience on ResearchGate. Read our cookies policy to learn more.