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Nobuyuki Ono

Publications and source records attributed to Nobuyuki Ono.

17 recordsLinked to original sources
PubMed2007

SAP regulation of follicular helper CD4 T cell development and humoral immunity is independent of SLAM and Fyn kinase.

Mutations in SH2D1A resulting in lack of SLAM-associated protein (SAP) expression cause the human genetic immunodeficiency X-linked lymphoproliferative disease. A severe block in germinal center development and lack of long-term humoral immunity is one of the most prominent phenotypes of SAP(-) mice. We show, in this study, that the germinal center block is due to an essential requirement for SAP expression in Ag-specific CD4 T cells to develop appropriate follicular helper T cell functions. It is unknown what signaling molecules are involved in regulation of SAP-dependent CD4 T cell help functions. SAP binds to the cytoplasmic tail of SLAM, and we show that SLAM is expressed on resting and activated CD4 T cells, as well as germinal center B cells. In addition, SAP can recruit Fyn kinase to SLAM. We have now examined the role(s) of the SLAM-SAP-Fyn signaling axis in in vivo CD4 T cell function and germinal center development. We observed normal germinal center development, long-lived plasma cell development, and Ab responses in SLAM(-/-) mice after a viral infection (lymphocytic choriomeningitis virus). In a separate series of experiments, we show that SAP is absolutely required in CD4 T cells to drive germinal center development, and that requirement does not depend on SAP-Fyn interactions, because CD4 T cells expressing SAP R78A are capable of supporting normal germinal center development. Therefore, a distinct SAP signaling pathway regulates follicular helper CD4 T cell differentiation, separate from the SLAM-SAP-Fyn signaling pathway regulating Th1/Th2 differentiation.

Animals↗
PubMed2006

Measles virus infection of SLAM (CD150) knockin mice reproduces tropism and immunosuppression in human infection.

The human signaling lymphocyte activation molecule (SLAM, also called CD150), a regulator of antigen-driven T-cell responses and macrophage functions, acts as a cellular receptor for measles virus (MV), and its V domain is necessary and sufficient for receptor function. We report here the generation of SLAM knockin mice in which the V domain of mouse SLAM was replaced by that of human SLAM. The chimeric SLAM had an expected distribution and normal function in the knockin mice. Splenocytes from the SLAM knockin mice permitted the in vitro growth of a virulent MV strain but not that of the Edmonston vaccine strain. Unlike in vitro infection, MV could grow only in SLAM knockin mice that also lacked the type I interferon receptor (IFNAR). After intraperitoneal or intranasal inoculation, MV was detected in the spleen and lymph nodes throughout the body but not in the thymus. Notably, the virus appeared first in the mediastinal lymph node after intranasal inoculation. Splenocytes from MV-infected IFNAR(-/-) SLAM knockin mice showed suppression of proliferative responses to concanavalin A. Thus, MV infection of SLAM knockin mice reproduces lymphotropism and immunosuppression in human infection, serving as a useful small animal model for measles.

Animals↗
PubMed2005

Comparison of biomechanical and histological properties in dog carotid arteries injured by neointima or intimal thickening.

A general formula (Oka and Azuma's equation) has been rigorously derived for the circumferential wall tension in a hollow cylindrical tube in equilibrium. To evaluate the validity and usefulness of Oka and Azuma's equation, T = P(1) x r(1) - P(2) x r(2) (T, circumferential wall tension; P(1) and P(2), internal and external pressures of the tube; r(1) and r(2), the corresponding internal and external radii), we experimentally investigated changes in circumferential wall tension of noninjured (control) and injured dog common carotid arteries by using a newly developed apparatus with a photo- and X-ray-sensitive image sensor. We also studied histological features of the control and injured arteries with special reference to the relation of biomechanical properties. Two types of animal models with injured arteries--balloon-induced neointima or external collar-induced intimal thickening--were adopted in the present study. In the control arteries, the circumferential wall tension was experimentally confirmed to change from negative to positive by an increase in intraluminal pressure ranging from 50 to 180 mmHg. The critical intraluminal pressure that produced 0 dyne/cm of the circumferential wall tension was around 135 mmHg. The activation of arterial smooth muscles caused a significant increase in the critical pressure in the control arteries. In the arteries injured by neointima, the critical intraluminal pressure was significantly lower than that in the control. The activation of smooth muscles also significantly increased the critical pressure in the injured arteries. Histological examination demonstrated the existence of a circumferential neointimal formation along with a shortening of the internal diameter. In other arteries injured by intimal thickening, the circumferential wall tension was always negative at intraluminal pressure ranging from 50 to 180 mmHg. Newly developed structures consisted of elastic and collagen fibers, smooth muscles, and extracellular matrix in the intima and media of the injured arteries. These experimental findings suggest that the circumferential wall tension of dog common carotid arteries has been confirmed experimentally to become negative. We have also concluded that circumferential wall tension calculated with Oka-Azuma's equation may be one of the best parameters for evaluating changes in the biomechanical and histological properties of pathologically injured arteries.

Animals↗
PubMed2005

Arachidonic Acid-Induced COX-1 and COX-2-Mediated Vasodilation in Rat Gingival Arterioles In Vivo.

The roles of cyclooxygenase (COX) and prostaglandins (PGs) in the regulation of vasoreactivity of rat gingival arterioles in vivo were evaluated by sing an intravital microscope. The superfusion of indomethacin (a nonselective COX inhibitor) or SC-560 (a selective COX-1 inhibitor) onto the gingiva significantly constricted the arterioles, though NS-398 (a selective COX-2 inhibitor) did not affect the diameter of the arterioles. The SC-560-mediated constriction of the arterioles was completely reversed by an additional treatment with arachidonic acid (AA). The superfusion of AA, beraprost-Na (an analogue of PGI2) or PGE2 onto the gingival significantly dilated the arterioles dose-dependently. The AA-induced dilation of the arterioles was significantly reduced by the treatment with SC-560 or NS-398. The expression of COX-1 and COX-2 were positive in the endothelium, but not the smooth muscles, of the arterioles. The expression of PGE synthase (PGES) was found only in the smooth muscles, but not the endothelium, of the arterioles. Neither the endothelium nor the smooth muscles of the arterioles expressed PGI synthase (PGIS). These findings suggest that the COX-2-mediated PG cascade may collaborate with the COX-1 pathway in the regulation of arteriolar myogenic activity in rat gingiva in the case of the supply of a large amount of AA.

Animals↗
PubMed2005

Effective permeability of hydrophilic substances through walls of lymph vessels: roles of endothelial barrier.

The wall effective permeability of hydrophilic substances labeled with fluorescent dyes was evaluated in an isolated cannulated rat single lymph vessel through a videomicroscope system. Sodium fluorescein (NaFl; 332 mol wt) and FITC-dextrans (4,400, 12,000, and 71,200 mol wt) were administered into the intraluminal space of the lymph vessels and then excited by a Xenon lamp. Changes in the fluorescence intensity of the dyes were continuously measured by a silicon-intensified target camera through appropriate filters. The net flux of each dye in the wall of the lymph vessels was calculated by the relationship between the fluorescence intensity and the concentration of the dyes. NaFl and FITC-dextran 4,400 in the intraluminal space of isolated rat lymph vessels significantly penetrated the wall of the lymph vessels. FITC-dextran 12,000 in the intraluminal space of isolated rat lymph vessels slightly passed through the lymphatic wall, whereas FITC-dextran 71,200 did not penetrate the wall. Intraluminal pressures ranging from 4 to 8 cm H(2)O did not significantly affect the net flux of dyes used in the present study. After administration of 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate into the lymph vessels, the net flux of FITC-dextran 4,400 and 12,000 but not 71,200 was augmented significantly. These results suggest that small molecular hydrophilic substances (< or =4,400) are permeable from the intraluminal to extraluminal space of isolated lymph vessels and that the endothelial cell surface structure may play a barrier role in the effective permeability of large molecular hydrophilic substances (4,400 to 12,000) through the wall of the lymph vessels.

Animals↗
PubMed2005

Accessory protein-like is essential for IL-18-mediated signaling.

IL-18 is an essential cytokine for both innate and adaptive immunity. Signaling by IL-18 requires IL-18Ralpha, which binds specifically to the ligand and contains sequence homology to IL-1R and TLRs. It is well established that IL-1R signaling requires an accessory cell surface protein, AcP. Other accessory proteins also exist with roles in regulating TLR signaling, but some have inhibitory functions. An AcP-like molecule (AcPL) has been identified with the ability to cooperate with IL-18Ralpha in vitro; however, the physiological function of AcPL remains unknown. In this study, we demonstrate that IL-18 signals are abolished in AcPL-deficient mice and cells. Splenocytes from mutant mice fail to respond to IL-18-induced proliferation and IFN-gamma production. In particular, Th1 cells lacking AcPL fail to produce IFN-gamma in response to IL-18. AcPL-deficient neutrophils also fail to respond to IL-18-induced activation and cytokine production. Furthermore, AcPL is required for NK-mediated cytotoxicity induced by in vivo IL-18 stimulation. However, AcPL is dispensable for the activation or inhibition of IL-1R and the various TLR signals that we have examined. These results suggest that AcPL is a critical and specific cell surface receptor that is required for IL-18 signaling.

Animals↗
PubMed2005

A new preparation for visualizing lymphatic flow pathway in isolated rat lymph nodes.

BACKGROUND: There is no reported study in which the lymphatic flow pathway in lymph nodes has been visualized and investigated in in vitro studies. The purpose of the present study is first to develop an isolated rat lymph node preparation circulated through the afferent and efferent lymph vessels in order to visualize lymphatic flow pathway within the node by using a video microscope system, and then to evaluate lymphatic flow dynamics by using fluorescence-labeled substances. METHODS AND RESULTS: In the present study, rat iliac lymph node was isolated. The afferent and efferent lymph vessels of the lymph node were cannulated with glass micropipettes in an organ chamber, while the small-sized arteries and veins connected to the lymph node were secured with sutures. Krebs-bicarbonate solution with or without fluorescent probes [FITCdextran, mol. weight; 77,000 and/or fluoresbrite carboxylate-microspheres (FC-microspheres) mean diameter of 1 microm] was circulated through the lymph vessels of the node. The time-dependent lymphatic pathway of fluorescent probes was investigated with a video microscope system. FTIC-dextran first spread through the cortex and subsequently reached the medulla of the lymph node. A follicle-like structure became evident in the cortex. FITC-dextran appeared in the efferent lymph vessel at 109 +/- 21 sec after its circulation began, while FC-microspheres distributed in the lymph node did not emerge from the node within 20 min after their introduction. CONCLUSIONS: In vitro preparations constructed in the present study will enable us to visualize the lymphatic flow pathway of fluorescent substances within the isolated iliac lymph nodes of rats in the absence of blood circulation.

Animals↗
PubMed2004

Genetic evidence linking SAP, the X-linked lymphoproliferative gene product, to Src-related kinase FynT in T(H)2 cytokine regulation.

SAP is an adaptor mutated in X-linked lymphoproliferative disease. It plays a critical role in T helper 2 (T(H)2) cytokine production. This function was suggested to reflect the capacity of SAP to associate with SLAM family receptors and enable tyrosine phosphorylation signaling by these receptors through SAP-mediated recruitment of Src-related kinase FynT. Here, we addressed by genetic means the importance of the SAP-FynT interaction in normal T cell functions. By creating a mouse in which the FynT binding site of SAP was inactivated in the germ line (sap(R78A) mouse) and by analyzing mice lacking SAP, FynT or SLAM, evidence was obtained that the SAP-FynT cascade is indeed crucial for normal T(H)2 functions in vitro and in vivo. These data imply that SAP is necessary for T(H)2 cytokine regulation primarily as a result of its capacity to recruit FynT. They also establish a previously unappreciated role for FynT in SAP-dependent T(H)2 cytokine regulation.

Animals↗
PubMed2004

Dissection of measles virus V protein in relation to its ability to block alpha/beta interferon signal transduction.

Interferon (IFN)-alpha and -beta are the main cytokines for innate immune responses against viral infections. To replicate efficiently in the hosts, viruses have evolved various countermeasures to the IFN response. The V protein of measles virus (MV) has been shown to block IFN-alpha/beta signalling. Here, the wild-type IC-B strain of MV was shown to grow comparably in the presence and absence of IFN-alpha, whereas replication of the Edmonston tag strain recovered from cloned DNA was strongly suppressed in its presence. The V protein of the IC-B strain, but not the Edmonston tag strain, blocked IFN-alpha signalling. The V protein of the Edmonston strain from the ATCC also inhibited IFN-alpha signalling. There were three amino acid differences between the V proteins of the Edmonston ATCC and tag strains, and substitutions of both residues at positions 110 and 272 were required for the Edmonston ATCC V protein to lose IFN-antagonist activity. The P protein of the IC-B strain, which shares the N-terminal 231 aa residues with the V protein, also inhibited IFN-alpha signalling. Indeed, fragments comprising only those 231 residues of the IC-B and Edmonston ATCC V proteins, but not the Edmonston tag V protein, were able to block IFN-alpha signalling. However, the N-terminal region of the Edmonston tag V protein, when attached to the C-terminal region of the Edmonston ATCC V protein, inhibited IFN-alpha signalling. Taken together, our results indicate that both the N- and C-terminal regions contribute to the IFN-antagonist activity of the MV V protein.

Animals↗
PubMed2003

Hsp70 promotes antigen-presenting cell function and converts T-cell tolerance to autoimmunity in vivo.

Pathogens or pathogen-associated molecular patterns can signal to cells of the innate immune system and trigger effective adaptive immunity. However, relatively little is known about how the innate immune system detects tissue injury or necrosis. Evidence suggests that the release of heat-shock proteins (HSPs) may provide adjuvant-like signals, but the ability of HSPs to promote activation or tolerance in vivo has not been addressed. In this study we show that Hsp70 promotes dendritic cell (DC) function and, together with antigen, triggers autoimmune disease in vivo.

Animals↗
PubMed2003

Establishment of rat lymphatic endothelial cell line.

OBJECTIVE: The objective of the present study was to establish a rat lymphatic endothelial cell line and then to investigate the morphological and immunohistochemical properties of the cells. METHODS: The lymphatic endothelial cells of rat thoracic ducts were isolated enzymatically by trypsin digestion and were cultured in endothelium growth medium (EGM)-2 in an atmosphere of low oxygen (5% O(2), 5% CO(2), and 90% N(2)) or high oxygen (21% O(2), 5% CO(2), and 74% N(2)). RESULTS: The number of the cells cultured in the low-oxygen atmosphere was significantly larger than that obtained in the high-oxygen atmosphere. The cultured cells in the low-oxygen atmosphere showed a monolayer with uniform cobblestone appearance, suggesting the morphological properties of endothelial cells. Factor VIII-related antigen and cell surface carbohydrates (i.e., D-galactose alpha and D-N-acetylgalactosamine alpha) were found on the lymphatic cultured cells. The phagocytosis of 1,1-diocadecyl1-3,3,3',3'-tetramethylindo-carbocyanine perchlorate-labeled acetylated low-density lipoprotein also was observed in the cultured cells. The cytoskeleton protein F-actin was located on the plasma membrane of the cultured cells as circumferential thin bundles and in the cytoplasma as filamentous bundles. CONCLUSIONS: The present study indicates that the choice of EGM-2 as a culture medium and the hypoxic atmosphere ( approximately 5%) enabled us to establish rat lymphatic endothelial cell line.

Actins↗
PubMed2003

Histidine at position 61 and its adjacent amino acid residues are critical for the ability of SLAM (CD150) to act as a cellular receptor for measles virus.

Signalling lymphocyte activation molecule (SLAM, also known as CD150), a membrane glycoprotein involved in lymphocyte activation, has two extracellular immunoglobulin superfamily domains, V and C2. It has been shown previously that human SLAM is a cellular receptor for measles virus (MV) and that its V domain is necessary and sufficient for receptor function. Although mouse SLAM has functional and structural similarity to human SLAM, it hardly acts as a receptor for MV. By producing human/mouse chimeric molecules and assessing their receptor function with a vesicular stomatitis virus pseudotype assay, the region at amino acid positions 58-67 was found to be critically responsible for the difference in MV receptor function between human and mouse SLAMs. Exchange of this region allowed mouse SLAM to act as a receptor for MV, almost comparable to human SLAM. Among three amino acid differences (positions 60, 61 and 63) in this region, histidine 61 present in human SLAM was most significant, but combined substitutions with this residue and one or both of isoleucine 60 and valine 63 increased further the receptor activity of mouse SLAM. On the other hand, converse substitution at position 61 compromised receptor function of human SLAM. Thus, histidine 61 and its adjacent residues at positions 60 and 63 are critical for SLAM to act as a receptor for MV. Notably, the pseudotype assay indicated that residues at these three positions are also critical for the function of SLAM as a receptor for canine distemper virus.

Animals↗
PubMed2003

Efficient isolation of wild strains of canine distemper virus in Vero cells expressing canine SLAM (CD150) and their adaptability to marmoset B95a cells.

We have previously shown that canine signaling lymphocyte activation molecule (SLAM; also known as CD150) acts as a cellular receptor for canine distemper virus (CDV). In this study, we established Vero cells stably expressing canine SLAM (Vero.DogSLAMtag cells). Viruses were isolated in Vero.DogSLAMtag cells one day after inoculation with spleen samples from five out of seven dogs with distemper. By contrast, virus isolation with reportedly sensitive marmoset B95a cells was only successful from three diseased animals at 7 to 10 days after inoculation, and no virus was recovered from any dogs when Vero cells were used for isolation. The CDV strain isolated in Vero.DogSLAMtag cells did not cause cytopathic effects in B95a and human SLAM-expressing Vero cells, whereas the strain isolated in B95a cells from the same dog did so in canine or human SLAM-expressing Vero cells as well as B95a cells. There were two amino acid differences in the hemagglutinin sequence between these strains. Cell fusion analysis after expression of envelope proteins and vesicular stomatitis virus pseudotype assay showed that their hemagglutinins were responsible for the difference in cell tropism between them. Site-directed mutagenesis indicated that glutamic acid to lysine substitution at position 530 of the hemagglutinin was required for the adaptation to the usage of marmoset SLAM. Our results indicate that Vero cells stably expressing canine SLAM are highly sensitive to CDV in clinical specimens and that only a single amino acid substitution in the hemagglutinin can allow the virus to adapt to marmoset SLAM.

Adaptation, Physiological↗
PubMed2002

Electrical stimulation-induced alpha1- and alpha2-adrenoceptors-mediated contractions of isolated canine lymph nodes.

The contractile effects of alpha-adrenoceptor agonists and field electrical stimulation were investigated pharmacologically in canine isolated tracheobronchial lymph nodes. Addition of noradrenaline (NA), phenylephrine (Phe) and UK14,304 caused dose-related contractions of the isolated lymph nodes. Pretreatment with prazosin (3 x 10(-9), 3 x 10(-8) and 3 x 10(-7) M) shifted the concentration-response curve for phenylephrine to the right, whereas yohimbine (3 x 10(-7) M) did not affect the contractile responses to phenylephrine. On the other hand, the concentration-response curve for UK 14,304 shifted to the right by treatment with yohimbine (3 x 10(-9), 3 x 10(-8) and 3 x 10(-7) M) but not by prazosin (3 x 10(-7) M). Field electrical stimulation (25 V, 0.7 ms, 16 Hz) produced contractile responses of the lymph nodes. The electrical stimulation-induced contractions were completely reduced by pretreatment with tetrodotoxin (TTX) (3 x 10(-7) M) or bretylium (10(-6) M). Furthermore, phentolamine (10(-8), 10(-7) and 10(-6) M), prazosin (3 x 10(-9) and 3 x 10(-8) M) and yohimbine (3 x 10(-8) and 3 x 10(-7) M) significantly reduced the electrical stimulation-induced contractions in the preparations. The present findings suggest that there are both alpha1- and alpha2-adrenoceptors located on the smooth muscle cells in canine tracheobronchial lymph nodes, and that the adrenoceptors-mediated excitatory mechanisms of adrenergic innervation exist in the lymph nodes.

Adrenergic alpha-Agonists↗
PubMed2002

SLAM (CD150)-independent measles virus entry as revealed by recombinant virus expressing green fluorescent protein.

Wild-type measles virus (MV) strains use human signaling lymphocyte activation molecule (SLAM) as a cellular receptor, while vaccine strains such as the Edmonston strain can use both SLAM and CD46 as receptors. Although the expression of SLAM is restricted to cells of the immune system (lymphocytes, dendritic cells, and monocytes), histopathological studies with humans and experimentally infected monkeys have shown that MV also infects SLAM-negative cells, including epithelial, endothelial, and neuronal cells. In an attempt to explain these findings, we produced the enhanced green fluorescent protein (EGFP)-expressing recombinant MV (IC323-EGFP) based on the wild-type IC-B strain. IC323-EGFP showed almost the same growth kinetics as the parental recombinant MV and produced large syncytia exhibiting green autofluorescence in SLAM-positive cells. Interestingly, all SLAM-negative cell lines examined also showed green autofluorescence after infection with IC323-EGFP, although the virus hardly spread from the originally infected individual cells and thus did not induce syncytia. When the number of EGFP-expressing cells after infection was taken as an indicator, the infectivities of IC323-EGFP for SLAM-negative cells were 2 to 3 logs lower than those for SLAM-positive cells. Anti-MV hemagglutinin antibody or fusion block peptide, but not anti-CD46 antibody, blocked IC323-EGFP infection of SLAM-negative cells. This infection occurred under conditions in which entry via endocytosis was inhibited. These results indicate that MV can infect a variety of cells, albeit with a low efficiency, by using an as yet unidentified receptor(s) other than SLAM or CD46, in part explaining the observed MV infection of SLAM-negative cells in vivo.

Animals↗
PubMed2001

Induction of the measles virus receptor SLAM (CD150) on monocytes.

Wild-type strains of measles virus (MV) isolated in B95a cells use the signalling lymphocyte activation molecule (SLAM; also known as CD150) as a cellular receptor, whereas the Edmonston strain and its derivative vaccine strains can use both SLAM and the ubiquitously expressed CD46 as receptors. Among the major target cells for MV, lymphocytes and dendritic cells are known to express SLAM after activation, but monocytes have been reported to be SLAM-negative. In this study, SLAM expression on monocytes was examined under different conditions. When freshly isolated from the peripheral blood, monocytes did not express SLAM on the cell surface. However, monocytes became SLAM-positive after incubation with phytohaemagglutinin, bacterial lipopolysaccharide or MV. Anti-SLAM monoclonal antibodies efficiently blocked infection of activated monocytes with a wild-type strain of MV. These results indicate that SLAM is readily induced and acts as a monocyte receptor for MV.

Antigens, CD↗