Biomedical subjects

Toshihide Nishimura

Publications and source records attributed to Toshihide Nishimura.

24 records · Page 2Linked to original sources

PubMed2003

Proteomic approach to apoptotic thymus maturation.

Apoptosis is an essential process for selection of T lymphocytes specific for foreign antigen in the process of mammalian thymus maturation. Proteomics, a comprehensive study of proteins expressed in a cell, will facilitate the systematic analysis of protein molecules related to such a complicated biological system. Protein expression profiles including information about protein signatures, localization and their quantitative changes with extracellular stimulations are extremely useful to construct intracellular pathway models resulting in the apoptotic cell death.

Apoptosis↗

PubMed2003

Angiotensin I-converting enzyme inhibitory peptides in a hydrolyzed chicken breast muscle extract.

The blood pressure of spontaneously hypertensive rats (SHRs) decreased after oral administration of an extract prepared from chicken breast muscle, falling maximally to 50 mmHg lower than before. This effect continued for at least 4 h after administration. The peptides possessing hypotensive activity in the chicken extract were examined by measuring the inhibitory activity (IC(50)) against angiotensin I-converting enzyme (ACE). The inhibitory activity of the chicken extract was 1060 mg%, whereas the activity of the extract treated with an Aspergillus protease and gastric proteases (trypsin, chymotrypsin, and intestinal juice) became stronger, reaching 1.1 mg%. Peptides in this hydrolysate of the extract were isolated by HPLC on a reversed-phase column, and their N-terminal sequences were analyzed. Three peptides possessed a common sequence, Gly-X-X-Gly-X-X-Gly-X-X, which was homologous with that of collagen. The peptide Gly-Phe-Hyp-Gly-Thr-Hyp-Gly-Leu-Hyp-Gly-Phe showed the strongest inhibitory activity (IC(50) = 42 microM).

Amino Acid Sequence↗

PubMed2002

Some human B and T cell epitopes of bovine serum albumin, the major beef allergen.

Bovine serum albumin (BSA) is the major beef allergen. Since IgE and T cell recognitions are central to the specific immune response to allergens, the identification and immunologic characterization of B and T cell epitopes of BSA represent important steps in the development of treatments for beef allergy. Prior to our experiments, we hypothesized that BSA-specific antibodies and T cells react primarily with sequential epitopes in which the amino acid sequences differ greatly between bovine and human albumin. To clarify this hypothesis, 16 peptides corresponding to such regions were synthesized as candidate epitopes. Among them, at least two regions, aa336-345 and aa451-459, were found to be B cell (IgE-binding) epitopes. In inhibition ELISA experiments, EYAV (aa338-341) and LILNR (aa453-457) bound to patient IgE antibodies and were found to be the cores of the IgE-binding epitopes. Three regions, DDSPDLPKLKPDPNTLC (aa107-123), PHACYTSVFDKLKHLVDEP (aa364-382), and LSLILNRLC (aa451-459), were found to induce T cell proliferation in more than half of the patients tested. Of interest was that these three regions were also recognized by B cells. Information concerning human B and T cells epitopes can contribute greatly to the elucidation of the etiology of beef allergy.

Allergens↗

PubMed2002

The selective triggering of CD40 on keratinocytes in vivo enhances cell-mediated immunity.

CD40 is expressed on a wide array of hematopoietic and non-hematopoietic cells, including keratinocytes. The pivotal in vivo function of CD40 on hematopoietic cells in the regulation of both humoral and cell-mediated immunity is well established. However, whether CD40 expression on non-hematopoietic cells influences immunity has until now not been addressed. Therefore, we transgenically expressed human CD40 (hCD40) under the control of the keratin 14 promoter to drive expression of hCD40 in basal keratinocytes of mice. When we selectively engaged hCD40 in vivo on the keratinocytes of these mice, the keratinocytes secreted TNF-alpha, resulting in dendritic cell migration to draining lymph nodes and enhanced in vitro T cell priming to an epicutaneously applied chemical sensitizer. Exclusive CD40 engagement on keratinocytes during a contact hypersensitivity response displayed exacerbated and prolonged cutaneous immune reactions relative to control mice. Thus, CD40 engagement on non-hematopoietic cells, such as keratinocytes, can amplify cutaneous and regional T cell responses in vivo.

Animals↗

PubMedDate not supplied

Multidimensional protein profiling technology and its application to human plasma proteome.

In clinical and diagnostic proteomics, it is essential to develop a comprehensive and robust system for proteome analysis. Although multidimensional liquid chromatography/tandem mass spectrometry (LC/MS/MS) systems have been recently developed as powerful tools especially for identification of protein complexes, these systems still some drawbacks in their application to clinical research that requires an analysis of a large number of human samples. Therefore, in this study, we have constructed a technically simple and high throughput protein profiling system comprising a two-dimensional (2D)-LC/MS/MS system which integrates both a strong cation exchange (SCX) chromatography and a microLC/MS/MS system with micro-flowing reversed-phase chromatography. Using the microLC/MS/MS system as the second dimensional chromatography, SCX separation has been optimized as an off-line first dimensional peptide fractionation. To evaluate the performance of the constructed 2D-LC/MS/MS system, the results of detection and identification of proteins were compared using digests mixtures of 6 authentic proteins with those obtained using one-dimensional microLC/MS/MS system. The number of peptide fragments detected and the coverage of protein sequence were found to be more than double through the use of our newly built 2D-LC/MS/MS system. Furthermore, this multidimensional protein profiling system has been applied to plasma proteome in order to examine its feasibility for clinical proteomics. The experimental results revealed the identification of 174 proteins from one serum sample depleted HSA and IgG which corresponds to only 1 microL of plasma, and the total analysis run time was less than half a day, indicating a fairly high possibility of practicing clinical proteomics in a high throughput manner.

Blood Proteins↗

PubMedDate not supplied

Expression of potential lymphocyte trafficking mediator molecules in the mammary gland.

The mammary gland performs a variety of immunological functions, including protecting itself from mastitis and protecting neonates from infectious agents. Several molecules that mediate lymphocyte trafficking in the immune system are also expressed in the mammary gland. This review is focused on the immunological function of these molecules, especially glycosylation-dependent cell adhesion molecule-1 (GlyCAM-1) and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in the mammary gland. GlyCAM-1 is expressed in the lactating mouse mammary gland. Endothelial cells produce this protein and secrete it into milk. The glycosylated modification of mammary gland GlyCAM-1 is different from that of the lymph nodes, and lacks the binding ability for L-selectin on lymphocytes. GlyCAM-1 in the mammary gland is not involved in lymphocyte migration, and probably has another function besides that of the lymph nodes. MAdCAM-1 is expressed on endothelial cells of small venules around mouse mammary lobules during lactation. This molecule has the ability to interact with alpha4beta7 integrin on lymphocytes and mediates lymphocyte recruitment to the mammary gland. The density of beta7+/CD3+ T-cells is correlated with the density of the MAdCAM-1-stained area, suggesting that MAdCAM-1 may mediate the migration of these cells. In contrast, there is no relationship between MAdCAM-1 expression and the number of beta7+/c-IgA+ B-cells, implying that some other factor is involved in lymphocyte migration to the mammary gland. Chemokines, such as IL-8, GRO-alpha, MCP-1, RANTES and MEC, have been detected in human and mouse mammary glands. Although little information is available, these molecules may contribute to lymphocyte migration to the mammary gland.

Animals↗