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Tetsu Nishiwaki

Publications and source records attributed to Tetsu Nishiwaki.

5 recordsLinked to original sources
PubMed2005

Plasmacytoid DCs help lymph node DCs to induce anti-HSV CTLs.

Antiviral cell-mediated immunity is initiated by the dendritic cell (DC) network in lymph nodes (LNs). Plasmacytoid DCs (pDCs) are known to migrate to inflamed LNs and produce interferon (IFN)-alpha, but their other roles in antiviral T cell immunity are unclear. We report that LN-recruited pDCs are activated to create local immune fields that generate antiviral cytotoxic T lymphocytes (CTLs) in association with LNDCs, in a model of cutaneous herpes simplex virus (HSV) infection. Although pDCs alone failed to induce CTLs, in vivo depletion of pDCs impaired CTL-mediated virus eradication. LNDCs from pDC-depleted mice showed impaired cluster formation with T cells and antigen presentation to prime CTLs. Transferring circulating pDC precursors from wild-type, but not CXCR3-deficient, mice to pDC-depleted mice restored CTL induction by impaired LNDCs. In vitro co-culture experiments revealed that pDCs provided help signals that recovered impaired LNDCs in a CD2- and CD40L-dependent manner. pDC-derived IFN-alpha further stimulated the recovered LNDCs to induce CTLs. Therefore, the help provided by pDCs for LNDCs in primary immune responses seems to be pivotal to optimally inducing anti-HSV CTLs.

Animals↗
PubMed2004

Evidence for recruitment of plasmacytoid dendritic cell precursors to inflamed lymph nodes through high endothelial venules.

Recruitment of dendritic cells (DCs) to lymph nodes (LNs) is pivotal to the establishment of immune response. Whereas DCs have been proven to undergo afferent lymphatic pathway to enter LNs from peripheral tissues, a question remains if DCs also migrate into LNs directly from the circulation. Here we demonstrate that plasmacytoid DC (pDC) precursors can transmigrate across high endothelial venules (HEVs) of inflamed LNs in mice. Bacterial infection induces a significant number of pDC and myeloid DC (mDC) precursors into the circulation. Both subsets express a common set of chemokine receptors except CXCR3, display parallel mobilization into the blood, but show distinct trafficking pathway to the LNs. In a short-term homing assay, whereas mDC precursors migrate to peripheral tissues and subsequently to draining LNs, pDC precursors directly enter the LNs in a CXCL9 and E-selectin dependent manner. Tumor necrosis factor-alpha controls not only DC precursor mobilization into the blood but also chemokine up-regulation on LN HEVs. A similar trafficking pathway is observed also in viral infection, and CXCR3(-/-) mice-derived pDC precursors show defective trans-HEV migration. This study clarifies the inflammation-dependent, chemokine-driven distinct property of DC precursor trafficking.

Animals↗
PubMed2004

Indigenous pulmonary Propionibacterium acnes primes the host in the development of sarcoid-like pulmonary granulomatosis in mice.

Although many cases of sarcoidosis are self-limiting with spontaneous remission, uncontrolled pulmonary granulomatosis with fibrosis produces intolerable long-term respiratory symptoms in a minority of patients. Individuals with chronic pulmonary sarcoidosis require an alternative therapy to corticosteroidal treatment because of its insufficient effectiveness. Although many researchers have considered infection as the triggering factor for this disease, the mechanisms by which the candidate causative organisms induce this disorder remain unclear. We report here that extrapulmonary sensitization to Propionibacterium acnes, which is one of the candidates to date, induced pulmonary Th-1 granulomas mainly in the subpleural and peribronchovascular regions often observed in sarcoidosis. These granulomas appear to be caused by indigenous P. acnes pre-existing in the lower respiratory tract of the normal lung, which is believed to be germ-free, and by an influx of P. acnes-sensitized CD4(+) T cells from the circulation. Importantly, the eradication of indigenous P. acnes with antibiotics alleviated the granulomatous lung disease. This is the first report to present clear evidence of the contribution of an indigenous pulmonary bacterium to the formation of granulomatous lesions in the lung. We propose that treatment targeting indigenous P. acnes in the lung may be a possible remedy for pulmonary sarcoidosis.

Animals↗
PubMed2003

[A case of pulmonary low-grade B cell lymphoma (MALT type) presenting seven years after gastric lymphoma resection].

A 71-year-old man was admitted to our hospital because of systemic edema and exertional dyspnea. Chest radiographs revealed infiltrative shadows in both lung fields, pleural effusion, and pericardial effusion. Seven years before, he had undergone gastric surgery for a gastric ulcer with lymphoid hyperplasia. In the pathologic diagnosis based on the percutaneous lung biopsy, hyalinizing granuloma was suspected. For a more thorough diagnosis, the patient was subjected to an open lung biopsy, and the final diagnosis was low-grade B-cell lymphoma of the MALT (mucosa-associated lymphoid tissue) type. Gallium scintigraphy showed accentuated accumulation in the left neck and hypothyroidism was present. Histologic re-examination of the resected stomach revealed infiltration of centrocyte-like cells and lymphoepithelial lesions, compatible with the pathologic features of MALT lymphoma. We considered that the gastric neoplasm and the pulmonary, pleural, and thyroid tumors of MALT lymphoma had occurred seven years apart in this case. Thyroid hormone replacement and CHOP therapy improved the symptoms and decreased the lung tumor size by 73%. MALT lymphomas tend to remain localized for a long period. The multiorgan involvement seen in this case is rather rare.

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