Biomedical subjects

Taiki Aoshi

Publications and source records attributed to Taiki Aoshi.

13 recordsLinked to original sources

PubMed2025

An adjuvant database for preclinical evaluation of vaccines and immunotherapeutics.

Adjuvants are immunostimulators used to enhance vaccine efficacy against infectious diseases. However, current methods for evaluating their efficacy and safety are limited, hindering large-scale screening. To address this, we developed a prototype Adjuvant Database (ADB) containing transcriptome data, generated using the same protocols as the widely used Open TG-GATEs (OTG) toxicogenomics database, covering 25 adjuvants across multiple species, organs, time points, and doses. This enabled cross-database integration of ADB and OTG. Transcriptomic patterns successfully distinguished each adjuvant regardless of organs or species. Using both databases, we built machine learning models to predict adjuvanticity and hepatotoxicity. Notably, we identified colchicine's adjuvant activity and FK565's liver toxicity through data-driven analysis. Overall, ADB combined with OTG offers a framework for transcriptomics-based, data-driven screening of adjuvant candidates.

Animals↗

PubMed2006

Cutting edge: TREM-2 attenuates macrophage activation.

The triggering receptor expressed on myeloid cells 2 (TREM-2) delivers intracellular signals through the adaptor DAP12 to regulate myeloid cell function both within and outside the immune system. The role of TREM-2 in immunity has been obscured by the failure to detect expression of the TREM-2 protein in vivo. In this study, we show that TREM-2 is expressed on macrophages infiltrating the tissues from the circulation and that alternative activation with IL-4 can induce TREM-2. TREM-2 expression is abrogated by macrophage maturation with LPS of IFN-gamma. Using TREM-2(-/-) mice, we find that TREM-2 functions to inhibit cytokine production by macrophages in response to the TLR ligands LPS, zymosan, and CpG. Furthermore, we find that TREM-2 completely accounts for the increased cytokine production previously reported by DAP12(-/-) macrophages. Taken together, these data show that TREM-2 is expressed on newly differentiated and alternatively activated macrophages and functions to restrain macrophage activation.

Adaptor Proteins, Signal Transducing↗

PubMed2005

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. In addition, the DC vaccination induced cytotoxic T-lymphocytes (CTL) and IFN-gamma-producing cells specific for a 9-mer CTL epitope on Ag85A molecule. This eliciting cellular immunity led to protection against wasting disease due to M. tuberculosis infection and induction of moderate bacterial clearance.

Animals↗

PubMed2005

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. Concomitantly, pGM215m-immunized mice showed significant protective immunity against lethal listerial challenge. These results suggest that immunization of a gene for GM-CSF inserted with a Th epitope is useful for eliciting a specific Th subset in vivo.

Animals↗

PubMed2005

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. The synthesis of overlapping peptides can be prohibitively expensive, and the algorithm programs used to predict CD8+ T cell epitopes are not always accurate. Here we describe a retroviral expression system that specifically allows longer polypeptides and shorter peptides to be expressed in the cytoplasm, and thereby to be processed onto class I MHC molecules. T cells from mice that were immunized with a DNA vaccine encoding MPT-51 were probed against MHC-compatible cell lines retrovirally transduced with overlapping gene fragments encoding 120-140 amino acids of the MPT-51 molecule. After further testing of shorter peptide sequences, we identified a CD8+ T cell epitope using cell lines expressing a relatively small number of algorithm-predicted candidate epitopes. We found that one of the requirements for cell surface display of the 20-mer peptide was the need for cotranslational ubiquitination. The restriction molecule was identified as Dd following transduction with MHC class I genes followed by transduction with the oligonucleotide encoding the epitope. The retroviral expression system described here is cost-effective, particularly if the target molecule is large, and could be adapted to identifying T cell epitopes recognized in infectious disease and against tumor cell antigens.

Algorithms↗

PubMed2005

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. However, we demonstrated that stimulation with IFN-gamma is capable of upregulating TLR9 expression in mDC to a level comparable with expression in pDC. Consistent with this observation, IL-12 p40 and IL-6 mRNA expression and IL-12 p70 secretion in response to CpG-oligodeoxynucleotides are enhanced in mDC pretreated with IFN-gamma compared with untreated cells. Therefore, TLR-mediated responses of DC subsets may be influenced not only by signals delivered by pathogens but also by regulatory signals from cytokines such as IFN-gamma.

Animals↗

PubMed2004

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. DNA vaccines have been designed for efficient transcription and translation of target genes by a variety of strategies. Also, various DNA vaccine strategies for induction of specific CTL and Th have been reported by taking into consideration antigen presentation pathways and the strategies have been shown to be effective to elicit particular T-cell responses. In this paper, we have reviewed these strategies, including our study on epitope-specific T-cell induction by DNA vaccination against Listeria monocytogenes infection. From this review, it has been surmised that, to induce strong immune responses by DNA vaccines, the immunization route and the immunization regimen, such as heterologous "prime-boost" regimen, should also be considered.

Animals↗

PubMed2004

Identification of murine H2-Dd- and H2-Ab-restricted T-cell epitopes on a novel protective antigen, MPT51, of Mycobacterium tuberculosis.

Both CD4(+) type 1 helper T (Th1) cells and CD8(+) cytotoxic T lymphocytes (CTL) play pivotal roles in protection against Mycobacterium tuberculosis infection. Here, we identified Th1 and CTL epitopes on a novel protective antigen, MPT51, in BALB/c and C57BL/6 mice. Mice were immunized with plasmid DNA encoding MPT51 by using a gene gun, and gamma interferon (IFN-gamma) production from the immune spleen cells was analyzed in response to a synthetic overlapping peptide library covering the mature MPT51 sequence. In BALB/c mice, only one peptide, p21-40, appeared to stimulate the immune splenocytes to produce IFN-gamma. Flow cytometric analysis with intracellular IFN-gamma and the T-cell phenotype revealed that the p21-40 peptide contains an immunodominant CD8(+) T-cell epitope. Further analysis with a computer-assisted algorithm permitted identification of a T-cell epitope, p24-32. In addition, a major histocompatibility complex class I stabilization assay with TAP2-deficient RMA-S cells transfected with K(d), D(d), or L(d) indicated that the epitope is presented by D(d). Finally, we proved that the p24-32/D(d) complex is recognized by IFN-gamma-producing CTL. In C57BL/6 mice, we observed H2-A(b)-restricted dominant and subdominant Th1 epitopes by using T-cell subset depletion analysis and three-color flow cytometry. The data obtained are useful for analyzing the role of MPT51-specific T cells in protective immunity and for designing a vaccine against M. tuberculosis infection.

Amino Acid Sequence↗

PubMed2003

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, 2.5 mg of the hapten reagent TNBS in 50% ethanol was administered into the colon. Two milligrams of rat anti-mouse IFN-gamma mAb, rat anti-mouse IL-12 mAb, or control rat IgG were administered intraperitoneally into mice before TNBS administration. Change in the body weight of mice was evaluated and the degree of inflammation of the colon of these mice was investigated histologically. Immunohistochemical and immunofluorescence analyses were performed to detect CD4+ T cells, macrophages and IL-12 in TNBS-induced colitis lesions. The profile of Th1 and Th2 cytokine expressions in colonic tissues was examined by cytokine-specific semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Single rectal administration of TNBS developed significant colitis in IFN-R-/- mice and anti-IFN-gamma mAb-pretreated mice, as well as control wild-type mice. Conversely, administration of TNBS produced no signs of colitis in IL-12 p40-/- and anti-IL-12 mAb-pretreated mice. CONCLUSIONS: IL-12, but not IFN-gamma, plays a pivotal role in the pathogenesis of TNBS-induced colitis.

Animals↗

PubMed2003

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. We found that the DC vaccine was capable of generating peptide-specific CD8+ T cells exhibiting LLO 91-99-specific cytotoxic activity and gamma interferon production, leading to induction of protective immunity to the bacterium. Furthermore, we demonstrated that the retrovirally transduced DC vaccine was more effective than a CTL epitope peptide-pulsed DC vaccine and a minigene DNA vaccine for eliciting antilisterial immunity. These results provide an alternative strategy in which retrovirally transduced DCs are used to design vaccines against intracellular pathogens.

Animals↗

PubMed2002

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. Concomitantly, pE215LAMP-immunised mice showed moderate, but significant protective immunity against listerial challenge. These results suggest that the intracellular targeting of a Th epitope to endosomal/lysosomal compartments by DNA immunisation is useful for eliciting a specific Th subset in vivo.

Animals↗

PubMed2002

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. The aim of this study was to determine whether treatment with curcumin prevents and ameliorates colonic inflammation in a mouse model of inflammatory bowel disease. METHODS: Mice with trinitrobenzene sulfonic acid (TNBS)-induced colitis were treated with 0.5%, 2.0%, or 5.0% curcumin in the diet, and changes in body weight together with histologic scores were evaluated. Colonic T-cell subsets were characterized, and NF-kappaB in colonic mucosa was detected by immunohistochemistry. NF-kappaB activity in the colonic mucosa was evaluated using electrophoretic mobility shift assay. Cytokine messenger RNA expression in colonic tissue was assessed by semiquantitative reverse-transcription polymerase chain reaction. RESULTS: Treatment of mice with curcumin prevented and improved both wasting and histopathologic signs of TNBS-induced colonic inflammation. Consistent with these findings, CD4(+) T-cell infiltration and NF-kappaB activation in colonic mucosa were suppressed in the curcumin-treated group. Suppression of proinflammatory cytokine messenger RNA expression in colonic mucosa was also observed. CONCLUSIONS: This study has shown for the first time that treatment with curcumin can prevent and improve murine experimental colitis. This finding suggests that curcumin could be a potential therapeutic agent for the treatment of patients with inflammatory bowel disease.

Animals↗

PubMed2002

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.

Animals↗