Biomedical subjects

Toshiaki Koda

Publications and source records attributed to Toshiaki Koda.

9 recordsLinked to original sources

PubMed2005

Development of a functional cDNA array for evaluation of the Th1/Th2 balance.

The immune balance controlled by CD4(+) helper T cell subsets (T helper 1 (Th1) and T helper 2 (Th2)) is crucial for immunoregulation and its imbalance causes various immune diseases including infections, allergic disorders and autoimmune diseases. Therefore, it is of great importance to develop a system of diagnosing Th1/Th2 imbalances for curing immune diseases. Here we developed a functional cDNA array filter useful for assessing the Th1/Th2 balance in mice. To overcome the disadvantages of conventional microarrays carrying thousands of genes, we prepared an array filter containing 40 Th1-specific and 32 Th2-specific genes, which were selected from over 8700 genes based on (i) the specificity of expression in Th1 or Th2 cells and (ii) an expression level which is high enough for detection using a DNA array. This array filter provided a prompt and precise evaluation for the skewing of the Th1/Th2 balance combined with our calculation algorithm. The bias toward Th1 or Th2 was evaluated visually at a glance by aligning the genes on the filter. Moreover, we succeeded in evaluating the skewing of the Th1/Th2 balance in vivo during acute graft versus host disease (GVHD). Thus, this array filter will provide a novel tool for evaluation of the Th1/Th2 balance in a variety of immune diseases.

Acute Disease↗

PubMed2005

[Development of DNA array filter useful for the analysis of Th1/Th2 balance].

DNA arrays are useful for determining the expression levels of a number of genes at once. We utilized this technique to evaluate the Th1/Th2 balance in vivo. Immune responses are controlled by two types of helper T cells, Th1 and Th2. Once the balance of Th1/Th2 immunity is disrupted, various immune diseases can develop. Thus, it is important to evaluate the Th1/Th2 balance in each patient for diagnosis, treatment and/or prophylaxis of immune diseases. We have identified a number of genes specifically expressed in Th1 or Th2 cells, and developed a DNA array filter spotted with these genes. We confirmed that this filter is useful for the evaluation of changes in the immune balance in vivo. Clinical application of this technology may lead to the tailor-made therapy of immune diseases through the evaluation of the immune balance in each patient.

Actins↗

PubMed2004

Generation of leukemia-specific T-helper type 1 cells applicable to human leukemia cell-therapy.

Leukemic dendritic cells (DC) were induced from the peripheral blood (PB) or bone marrow (BM) of leukemia patients by culture with (i) GM-CSF + IL-3 (neutral condition); (ii) GM-CSF + IL-3 + IL-12 + IFN-gamma (type 1-condition); or (iii) GM-CSF + IL-3 + IL-4 (type 2-condition). Although leukemic cells rapidly differentiated into adhesive leukemic DC in all culture conditions, type1-conditions were the most suitable for inducing leukemic DC expressing high levels of HLA and costimulatory molecules. Addition of IL-2 after 2 days of culture induced a preferential growth of minor T cell populations interacting with leukemic DC. In particular, IFN-gamma-producing CD4+ Th1 cells were efficiently expanded in type 1 culture conditions but nor in neutral or type 2-conditions. However, CD4+ T cells expanded in neutral conditions showed Th1-like functions if they were pulsed with IFN-gamma for 2 days before harvest. Such Th1 cells produced IFN-gamma and exhibited cytotoxicity in response to autologous leukemia cells. We further demonstrated that IFN-gamma production of leukemia-specific Th1 cells was blocked by anti-HLA-DR mAb. Thus, we established a novel culture system for inducing leukemia-specific Th1 cells.

Adult↗

PubMed2004

IFN-gamma-induced SOCS-1 regulates STAT6-dependent eotaxin production triggered by IL-4 and TNF-alpha.

The production of eotaxin, which is a critical mediator for airway inflammation, is inhibited by IFN-gamma. Here, we investigated the precise mechanisms underlying IFN-gamma-dependent inhibition of eotaxin production using mouse embryonic fibroblasts (MEF). MEF produced high levels of eotaxin in STAT6-dependent manner when they were cultured with both IL-4 and TNF-alpha. However, the eotaxin production by MEF was strongly inhibited by addition of IFN-gamma. Western-blotting analysis demonstrated that IFN-gamma downmodulated STAT6 phosphorylation induced by IL-4 and TNF-alpha. Moreover, IFN-gamma did not exhibit its inhibitory effect on both STAT6-phosphorylation and eotaxin production in MEF obtained from deficient mice in STAT1, a key molecule of IFN-gamma signaling. We also demonstrated that SOCS-1, a potent inhibitory molecule of IL-4 signaling, was induced by IFN-gamma in STAT1-dependent manner. This indicated that SOCS-1 might be involved in IFN-gamma-mediated STAT1-dependent inhibition of eotaxin production. In SOCS-1(-/-) MEF, IFN-gamma inhibited neither STAT6 phosphorylation nor eotaxin production induced by IL-4 and TNF-alpha. Conversely, retroviral transduction of SOCS-1 into MEF inhibited STAT6 phosphorylation and eotaxin production induced by IL-4 and TNF-alpha, in the absence of IFN-gamma. Thus, we demonstrated that IFN-gamma-induced inhibition of STAT6 phosphorylation and eotaxin production were mediated by SOCS-1 induced in STAT1-dependent manner.

Animals↗

PubMed2003

Functional expression of the TrkC gene, encoding a high affinity receptor for NT-3, in antigen-specific T helper type 2 (Th2) cells.

Neurotrophins, including nerve growth factor, brain-derived neurotrophic factor and neurotrophin-3 (NT-3) are essential factors for the development of the nervous system. In this report, we demonstrate gene expression of neurotrophins and their receptors in T helper 1 (Th1) and T helper 2 (Th2) cells induced from naïve CD4+ CD45RB+ T cells of ovalbumin-specific DO11.10 T cell receptor transgenic mice. Interestingly, the TrkC gene, which encodes a high affinity receptor for NT-3, was expressed in Th2 cells, but not in Th1 and naïve CD4+ T cells. Expression of the TrkC gene was markedly augmented by addition of anti-IFN-gamma monoclonal antibody (mAb) into the culture, whereas it was blocked by anti-IL-4 mAb. Moreover, NT-3 synergistically enhanced anti-CD3 mAb-induced IL-4 production by Th2 cells, but did not affect IFN-gamma production by Th1 cells. These data suggest that NT-3, through its receptor TrkC, plays a critical role in regulating the Th1/Th2 balance.

Animals↗

PubMed2003

Differential regulation of VLA-2 expression on Th1 and Th2 cells: a novel marker for the classification of Th subsets.

We found that T(h)1 cells derived from ovalbumin (OVA)-specific TCR transgenic (DO11.10) mice showed significantly higher levels of VLA-2 (CD49b/CD29) expression than T(h)2 cells. In the early days (until 6 days) during induction of T(h)1 or T(h)2 cells, the expression of VLA-2 was gradually increased on both T(h) subsets. Thereafter, VLA-2 expression was further up-regulated on T(h)1 cells until 13 days, while a significant decrease of VLA-2 was observed in T(h)2 cells, resulting in a marked difference of expression at day 13. Up-regulation of VLA-2 on T(h)1 cells was not impaired in IFN-gamma(-/-) T(h) cells nor blocked by anti-IL-12 mAb treatment on wild-type T(h) cells, suggesting that up-regulation of VLA-2 on T(h)1 cells occurs in an IFN-gamma- and IL-12-independent manner. In contrast, T(h) cells cultured under IL-4-depleted T(h)2 conditions abrogated the down-regulation of VLA-2 expression, suggesting that down-regulation of VLA-2 expression on T(h)2 cells was dependent on IL-4. The finding that STAT6(-/-) T(h)2 cells did not show any down-regulation of VLA-2 expression and expressed the same levels of VLA-2 as T(h)1 cells indicated a critical role for the IL-4 receptor/STAT6 signaling pathway in IL-4-dependent down-regulation of VLA-2 on T(h)2 cells. Stimulation of T(h)1 cells by VLA-2 ligands such as collagen type I or agonistic mAb provided co-stimulation for anti-CD3 mAb-induced IFN-gamma production. However, these ligations had little effect on the IL-4 production of T(h)2 cells. Together, these results indicate that VLA-2 is a novel functional marker that dissociates T(h)1 from T(h)2 cells, and thus might be useful for therapeutic monitoring of T(h)1-dependent immune diseases such as rheumatoid arthritis or Crohn's disease.

Animals↗

PubMed2003

Critical role of the Th1/Tc1 circuit for the generation of tumor-specific CTL during tumor eradication in vivo by Th1-cell therapy.

Th1 and Th2 cells obtained from OVA-specific T cell receptor transgenic mice completely eradicated the tumor mass when transferred into mice bearing A20-OVA tumor cells expressing OVA as a model tumor antigen. To elucidate the role of Tc1 or Tc2 cells during tumor eradication by Th1- or Th2-cell therapy, spleen cells obtained from mice cured of tumor by the therapy were re-stimulated with the model tumor antigen (OVA) for 4 days. Spleen cells obtained from mice cured by Th1-cell therapy produced high levels of IFN-gamma, while spleen cells from mice cured by Th2-cell therapy produced high levels of IL-4. Intracellular staining analysis demonstrated that a high frequency of IFN-gamma-producing Tc1 cells was induced in mice given Th1-cell therapy. In contrast, IL-4-producing Tc2 cells were mainly induced in mice after Th2-cell therapy. Moreover, Tc1, but not Tc2, exhibited a tumor-specific cytotoxicity against A20-OVA but not against CMS-7 fibrosarcoma. Thus, immunological memory essential for CTL generation was induced by the Th1/Tc1 circuit, but not by the Th2/Tc2 circuit. We also demonstrated that Th1-cell therapy is greatly augmented by combination therapy with cyclophosphamide treatment. This finding indicated that adoptive chemoimmunotherapy using Th1 cells should be applicable as a novel tool to enhance the Th1/Tc1 circuit, which is beneficial for inducing tumor eradication in vivo.

Animals↗

PubMed2003

An efficient method to prepare T cell receptor gene-transduced cytotoxic T lymphocytes type 1 applicable to tumor gene cell-therapy.

Genes encoding 2C T cell receptor (TCR) alpha, beta chains from H-2(b)-restricted L(d)-specific CD8(+) cells were successfully transduced into polyclonally activated CD8(+) cells by retroviral modification to generate antigen-specific cytotoxic T lymphocytes (CTL). Antigen-nonspecific CD8(+) T cells polyclonally expanded in the presence of interleukin (IL)-2, Th1 cytokines (interferon (IFN)-gamma and IL-12) and anti-IL-4 monoclonal antibody showed neither cytokine production nor cytotoxicity in response to L(d)-expressing P815 tumor cells. However, 2C-TCR gene-modified CD8(+) T cells exhibited both IFN-gamma production and cytotoxicity in response to P815 tumor cells. The antitumor activity of TCR gene-modified Tc1 cells was also demonstrated in vivo by Winn's assay. Thus, we have developed an efficient method to induce TCR gene-modified antigen-specific Tc1 cells that exhibit antitumor activity both in vitro and in vivo.

Animals↗

PubMed2002

[Genetically engineered mice and its application to bioindustry].

More than 2 decades have past since the first transgenic mouse was created. In this review we will focus on recent technologies in the field of mouse genetic engineering and on its application to bioindustry. The most important milestone in this field was the invention of the gene targeting technique. Recent improvement of this technique to conditional gene targeting together with the Cre/IoxP system further encouraged the generation of mutant mice. It is obvious that there will be a great demand for some mutant mice as experimental models of human disease or as resources of experimental material for basis biological research. Thus, creation of such mice would be a rewarding challenge for a biological enterprise.

Animals↗