Enhancement of protective immunity against intracellular bacteria using type-1 polarized dendritic cell (DC) vaccine.

The development of effective vaccine strategies for intracellular bacteria, including tuberculosis, is one of the major frontiers of medical research. Our previous studies showed that dendritic cell (DC) vaccine is a promising approach for eliciting protective immunity against intracellular bacteria. However, it has been reported that standard fully mature DCs show reduced ability to produce IL-12p70 upon subsequent interaction with antigen (Ag)-specific T cells, limiting their in vivo performance for vaccines.

Resistance of a rodent malaria parasite to a thymidylate synthase inhibitor induces an apoptotic parasite death and imposes a huge cost of fitness.

Background: The greatest impediment to effective malaria control is drug resistance in Plasmodium falciparum, and thus understanding how resistance impacts on the parasite's fitness and pathogenicity may aid in malaria control strategy.

Methodology/principal Findings: To generate resistance, P. berghei NK65 was subjected to 5-fluoroorotate (FOA, an inhibitor of thymidylate synthase, TS) pressure in mice.

A novel vaccine strategy to induce mycobacterial antigen-specific Th1 responses by utilizing the C-terminal domain of heat shock protein 70.

Heat shock protein 70 (HSP70) is a member of a highly conserved superfamily of intracellular chaperones called stress proteins that can activate innate and adaptive immune responses. We evaluated the effect of a fusion DNA vaccine that encoded mycobacterial HSP70 and MPT51, a major secreted protein of Mycobacterium tuberculosis. Spleen cells from mice immunized with fusion DNA of full-length HSP70 and MPT51 produced a higher amount of interferon-γ (IFN-γ) in response to the CD4+, but not the CD8+ T-cell epitope peptide on MPT51 than those from mice immunized with MPT51 DNA.

Identification of HLA-DR4-restricted T-cell epitope on MPT51 protein, a major secreted protein derived from Mycobacterium tuberculosis using MPT51 overlapping peptides screening and DNA vaccination.

We identified a novel HLA-DR4-restricted CD4+ T-cell epitope on a secreted antigen of Mycobacterium tuberculosis, MPT51, in 004149-MM HLA-DR4-transgenic mice which express HLA-DRB1*0401, but not murine MHC class II molecules. The mice were immunized with plasmid DNA encoding MPT51 using gene gun and interferon (IFN)-gamma production from the immune splenocytes was analyzed. In response to overlapping synthetic peptides covering the mature MPT51 sequence, only one peptide, p191-210, stimulated the splenocytes to produce IFN-gamma.

Intratracheal administration of third-generation lentivirus vector encoding MPT51 from Mycobacterium tuberculosis induces specific CD8+ T-cell responses in the lung.

The present study evaluates the potential of improved third-generation lentivirus vector with respect to their use as an in vivo-administered T-cell vaccine against tuberculosis. Intratracheal administration of the lentivirus vector encoding MPT51 of Mycobacterium tuberculosis could induce MPT51-specific CD8+ T cells in the mediastinal lymph nodes 2 weeks after the administration. The vaccination could generate MPT51-specific memory CD8+ T cells in the lung, but not in the lymph nodes.

Chemokine receptor-mediated delivery of mycobacterial MPT51 protein efficiently induces antigen-specific T-cell responses.

Here we evaluated the effects of immunization with a DNA vaccine encoding a fusion protein consisting of macrophage inflammatory protein-1alpha (MIP-1alpha) and MPT51 (a major secreted protein from Mycobacterium tuberculosis) on induction of specific CD8+ T cells. The DNA vaccine encoding the fusion protein could induce significantly higher number of the antigen-specific CD8+ T cells in mice than DNA vaccine encoding MPT51 alone. Also, splenocytes from mice immunized with the fusion DNA vaccine expressed higher level of IFN-gamma mRNA and protein upon stimulation with an epitope peptide derived from MPT51 than those from mice immunized with a mixture of two DNA vaccines encoding either MPT51 or MIP-1alpha.

In vivo hierarchy of individual T-cell epitope-specific helper T-cell subset against an intracellular bacterium.

Cellular immunity is indispensable for efficient protection against intracellular bacterial infection. CD4+ and CD8+ T cells specific for a variety of antigenic peptides derived from particular bacteria are induced after the infection. T cells recognizing different antigenic peptides have been speculated to have different functions in terms of the protective immunity.

Identification of an HLA-A*0201-restricted T-cell epitope on the MPT51 protein, a major secreted protein derived from Mycobacterium tuberculosis, by MPT51 overlapping peptide screening.

CD8+ T cells play a pivotal role in protection against Mycobacterium tuberculosis infection. We identified a novel HLA-A*0201-restricted CD8+ T-cell epitope on a dominant secreted antigen of M. tuberculosis, MPT51, in HLA-A*0201 transgenic HHD mice.

Immunization with dendritic cells loaded with alpha-galactosylceramide at priming phase, but not at boosting phase, enhances cytotoxic T lymphocyte activity against infection by intracellular bacteria.

We evaluated the effect of immunization with dendritic cells (DCs) pulsed with alpha-galactosylceramide (alphaGalCer) and listeriolysin O (LLO) 91-99 peptide, a dominant cytotoxic T lymphocyte (CTL) epitope of Listeria monocytogenes by observing the responses of specific CD8(+) T cells and in vivo CTL activity. DCs were pulsed with various combinations of alphaGalCer and LLO91-99 peptide and administered to BALB/c mice. Immunization with DCs pulsed with alphaGalCer and LLO91-99 at priming phase and with DCs pulsed with LLO91-99 alone at boosting phase induced stronger in vivo CTL activity, reduced the bacterial load in spleens of Listeria-challenged mice and augmented CD62L(+) CD8(+) central memory T cells compared with other immunization protocols.

Intracytosolic Listeria monocytogenes induces cell death through caspase-1 activation in murine macrophages.

Listeria monocytogenes induces apoptosis in vitro and in vivo in a variety of cell types. However, the mechanism of cell death in L. monocytogenes-infected macrophages was initially reported to be distinct from apoptosis.

Curcumin maintenance therapy for ulcerative colitis: randomized, multicenter, double-blind, placebo-controlled trial.

Background & Aims: Curcumin is a biologically active phytochemical substance present in turmeric and has pharmacologic actions that might benefit patients with ulcerative colitis (UC). The aim in this trial was to assess the efficacy of curcumin as maintenance therapy in patients with quiescent ulcerative colitis (UC).

Methods: Eighty-nine patients with quiescent UC were recruited for this randomized, double-blind, multicenter trial of curcumin in the prevention of relapse.

Immunization with dendritic cells retrovirally transduced with mycobacterial antigen 85A gene elicits the specific cellular immunity including cytotoxic T-lymphocyte activity specific to an epitope on antigen 85A.

In the present study, we evaluated antigen 85A (Ag85A) gene-transduced dendritic cells (DCs) vaccine against Mycobacterium tuberculosis. Murine bone marrow-derived DCs were retrovirally transduced with mycobacterial Ag85A gene and injected to BALB/c mice intravenously. The DC vaccine was capable of inducing purified protein derivative (PPD)- and the antigen-specific spleen cell proliferation and IFN-gamma production from both CD4+ and CD8+ T cells in spleens of the immune mice.

Immunization with a gene encoding granulocyte-macrophage colony-stimulating factor inserted with a single helper T-cell epitope of an intracellular bacterium induces a specific T-cell subset and protective immunity.

We evaluated here the effect of immunization with a gene encoding granulocyte-macrophage colony-stimulating factor (GM-CSF) inserted with a helper T cell (Th) epitope, listeriolysin O (LLO) 215-226 derived from Listeria monocytogenes on induction of a specific Th by gene gun bombardment. Immunization of C3H/He mice with pGM215m plasmid encoding murine GM-CSF inserted with LLO 215-226 Th epitope gave the epitope-specific proliferative responses of CD4(+) T lymphocytes. In addition, specific interferon-gamma production from the splenocytes was observed.

Expression mapping using a retroviral vector for CD8+ T cell epitopes: definition of a Mycobacterium tuberculosis peptide presented by H2-Dd.

Identification of CD8+ T cell epitopes is important because detection of specific CD8+ T cells after infection or immunization requires prior knowledge of epitope specificity. Furthermore, identification of CD8+ T cell epitopes permits the development of specific preventive and therapeutic approaches to both infections and tumors. Thus far, CD8+ T cell epitopes have been identified either using an overlapping peptide library covering an entire protein, or using algorithms designed to identify likely peptides that bind to major histocompatibility complex (MHC) class I molecules.

IFN-gamma overcomes low responsiveness of myeloid dendritic cells to CpG DNA.

Dendritic cells (DC) are professional APC that have an extraordinary capacity to prime naive T cells. It has been reported that human DC subsets express distinct toll-like receptor (TLR), which influences their function. In mice, we observed that plasmocytoid DC (pDC) express a higher level of TLR9 compared with myeloid DC (mDC) cultured with GM-CSF.

Butyrate suppresses hypoxia-inducible factor-1 activity in intestinal epithelial cells under hypoxic conditions.

Interaction between the products of intestinal bacteria and the intestinal epithelial cells is a key event in understanding the biological, physiological, and pathological functions of the intestinal epithelium. Here, we examined the effect of butyrate, one of the major intestinal bacterial products, on hypoxia-inducible factor-1 (HIF-1) activity under hypoxic conditions in intestinal epithelial cells. HIF-1 activity was assessed by luciferase assay using cytoplasmic extracts of intestinal epithelial cells, Caco-2, and IEC-6 cells.

Induction of protective cellular immunity against Mycobacterium tuberculosis by recombinant attenuated self-destructing Listeria monocytogenes strains harboring eukaryotic expression plasmids for antigen 85 complex and MPB/MPT51.

We report here the induction of specific protective cellular immunity against Mycobacterium tuberculosis by the employment of vaccination with recombinant attenuated Listeria monocytogenes strains. We constructed self-destructing attenuated L. monocytogenes Delta 2 strains carrying eukaryotic expression plasmids for the antigen 85 complex (Ag85A and Ag85B) and for MPB/MPT51 (mycobacterial protein secreted by M.

Cytotoxic T-lymphocyte-, and helper T-lymphocyte-oriented DNA vaccination.

DNA vaccines have advantages over other types of vaccines in that they can induce strong cellular immune responses, namely cytotoxic T lymphocytes (CTL) and helper T lymphocytes (Th). DNA vaccines are therefore considered a promising alternative to attenuated live vaccines in the field of infectious diseases. So far, various DNA vaccines have been generated and tried to induce a particular cellular immune response by virtue of recombinant DNA technology.

Evidence for the critical role of interleukin-12 but not interferon-gamma in the pathogenesis of experimental colitis in mice.

Background And Aims: The imbalance between helper T (Th)1/Th2 cytokines has been observed in human inflammatory bowel disease and various animal models. Because interleukin (IL)-12 and interferon-gamma (IFN-gamma) productions are known to be a hallmark of Th1-dominant intestinal inflammation such as 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis, we strictly addressed the roles of IFN-gamma and IL-12 in the development of colitis, employing knockout mice with IFN-gamma receptor (IFN-gammaR) or IL-12 p40 gene disruptions and mice administered with neutralizing monoclonal antibodies (mAbs) against IFN-gamma or IL-12.

Methods: To induce colitis, 2.

Induction of protective immunity to Listeria monocytogenes with dendritic cells retrovirally transduced with a cytotoxic T lymphocyte epitope minigene.

In the present study, we developed a cytotoxic T lymphocyte (CTL) epitope minigene-transduced dendritic cell (DC)-based vaccine against Listeria monocytogenes. Murine bone marrow-derived DCs were retrovirally transduced with a minigene for listeriolysin O (LLO) 91-99, a dominant CTL epitope of L. monocytogenes, and were injected into BALB/c mice intravenously.

Curcumin prevents and ameliorates trinitrobenzene sulfonic acid-induced colitis in mice.

Background & Aims: Curcumin is known to have a variety of pharmacologic effects, including antitumor, anti-inflammatory, and anti-infectious activities. The pleiotropic effects of curcumin are attributable at least in part to inhibition of transcriptional factor nuclear factor kappaB (NF-kappaB). However, the effect of curcumin on intestinal inflammation has hitherto not been evaluated.

Endosomal/lysosomal targeting of a single helper T-cell epitope of an intracellular bacterium by DNA immunisation induces a specific T-cell subset and partial protective immunity in vivo.

We evaluated here the effect of the intracellular targeting of a helper T-cell (Th) epitope, literiolysin O 215-226 derived from Listeria monocytogenes, on induction of a specific Th by gene gun immunisation. Immunisation of C3H/He mice with pE215LAMP plasmid encoding the Th epitope fused with the endosomal/lysosomal targeting signal of lysosome-associated membrane protein (LAMP)-1 gave the epitope-specific proliferative responses of CD4(+) T lymphocytes. In addition, specific interferon-gamma production from the splenocytes was observed.

Induction of protective immunity to Listeria monocytogenes by immunization with plasmid DNA expressing a helper T-cell epitope that replaces the class II-associated invariant chain peptide of the invariant chain.

Listeria epitope-specific helper T (Th) cells were able to be primed and induced in vivo by immunization with a plasmid carrying an invariant chain (Ii) gene whose class II-associated invariant chain peptide (CLIP) region was replaced by a Listeria Th epitope. Immunization of C3H/He mice with an Ii-LLO 215-226 plasmid induced specific interferon-gamma- and interleukin 2-producing Th cells and conferred significant protective immunity against listerial infection.