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Sachiko Miyake

Publications and source records attributed to Sachiko Miyake.

8 recordsLinked to original sources
PubMed2003

CD4+ NKT cells, but not conventional CD4+ T cells, are required to generate efferent CD8+ T regulatory cells following antigen inoculation in an immune-privileged site.

Following inoculation of Ag into the anterior chamber (a.c.), systemic tolerance develops that is mediated in part by Ag-specific efferent CD8(+) T regulatory (Tr) cells. This model of tolerance is called a.c.-associated immune deviation. The generation of the efferent CD8(+) Tr cell in a.c.-associated immune deviation is dependent on IL-10-producing, CD1d-restricted, invariant Valpha14(+) NKT (iNKT) cells. The iNKT cell subpopulations are either CD4(+) or CD4(-)CD8(-) double negative. This report identifies the subpopulation of iNKT cells that is important for induction of the efferent Tr cell. Because MHC class II(-/-) (class II(-/-)) mice generate efferent Tr cells following a.c. inoculation, we conclude that conventional CD4(+) T cells are not needed for the development of efferent CD8(+) T cells. Furthermore, Ab depletion of CD4(+) cells in both wild-type mice (remove both conventional and CD4(+) NKT cells) and class II(-/-) mice (remove CD4(+) NKT cells) abrogated the generation of Tr cells. We conclude that CD4(+) NKT cells, but not the class II molecule or conventional CD4(+) T cells, are required for generation of efferent CD8(+) Tr cells following Ag introduction into the eye. Understanding the mechanisms that lead to the generation of efferent CD8(+) Tr cells may lead to novel immunotherapy for immune inflammatory diseases.

Animals↗
PubMed2003

Heterozygous null mutation of myelin P0 protein enhances susceptibility to autoimmune neuritis targeting P0 peptide.

Mice with a heterozygous null mutation in myelin protein zero (P0(+/-)) develop late-onset clinical paralysis associated with inflammatory pathology in the peripheral nerves. Although the development of this illness is known to require T cells and macrophages, little is understood regarding the immunological defect in the mice. Here we report that young P0(+/-) mice, free from clinical manifestations, have a defect in central tolerance to P0, and are more prone to induction of experimental autoimmune neuritis (EAN) by sensitization against P0(180-199 )peptide. Notably, we found that the P0 gene is transcribed in the thymus of wild-type and the P0(+/-) mice in an amount proportional to the gene dosage. We then replaced the thymus of wild-type mice with that of the P0-deficient mice and vice versa. Immunization of these mice with P0(180-199 )revealed that a lower thymic P0 transcript would be associated with the higher recall T cell response to P0(180-199), thus accounting for the higher susceptibility of the P0(+/-) mice to P0-induced EAN. These results imply that a heterozygous mutation in an autoantigen could cause defective central tolerance to the autoantigen. As such, autoimmune T cells may play some role in "genetic" diseases caused by a heterozygous gene defect.

Amino Acid Sequence↗
PubMed2003

Microarray analysis identifies interferon beta-regulated genes in multiple sclerosis.

The molecular mechanisms for the interferon beta (IFNbeta) treatment of multiple sclerosis (MS) remain to be characterized. Using cDNA microarray technology, we have compared the gene expression profile of T and non-T cells derived from relapsing-remitting MS before and after treatment with IFNbeta-1b. IFNbeta treatment significantly altered expression of 21 genes out of 1263 at 3 and 6 months after treatment. These genes included nine with IFN-responsive promoter elements. Whereas there was no change in Th1 or Th2 marker genes, some of the changes were unexpected but coincided with the beneficial effect of IFNbeta in MS.

Adult↗
PubMed2003

Th2 bias of CD4+ NKT cells derived from multiple sclerosis in remission.

Although CD1d-restricted NKT cells have been implicated as a participant in the regulatory mechanism of autoimmune diseases, it remains unclear how they would regulate human autoimmune diseases such as multiple sclerosis (MS). Furthermore, although the NKT cells comprise CD4(+) and CD4(-) populations, prior studies have often represented them as simply a CD4(-) population. Given that CD4(+) and CD4(-) NKT cells may represent functionally distinct populations, it appears crucial to examine the individual NKT subset in autoimmune diseases. Here we studied the frequency and cytokine phenotypes of the CD4(+) and CD4(-) NKT cells in fresh peripheral blood mononuclear cells, and of alpha-galactosylceramide-stimulated short-term cell lines obtained during the remission or relapse phase of MS as compared with from healthy subjects (HS). Here we report that CD4(+) NKT line cells expanded from MS in remission (MS-rem) would produce a larger amount of IL-4 than those from HS or from MS in relapse (MS-rel). They were significantly biased for T(h)2 as judged by the IL-4/IFN-gamma balance. However, there was no functional bias toward T(h)1 or T(h)2 in CD4(-) NKT line cells from MS-rem due to the defects in both IFN-gamma and IL-4 production, compared with HS. Of note, although double-negative NKT cells in the periphery were greatly reduced, the reduction of CD4(+) NKT cells was only marginal, if any, in MS-rem compared with HS. The T(h)2 bias of CD4(+) NKT line cells from MS-rem may support an immunoregulatory role for the CD4(+) NKT cells in vivo.

Adult↗
PubMed2002

Negative regulation of Lck by Cbl ubiquitin ligase.

The Cbl-family ubiquitin ligases function as negative regulators of activated receptor tyrosine kinases by facilitating their ubiquitination and subsequent targeting to lysosomes. Cbl associates with the lymphoid-restricted nonreceptor tyrosine kinase Lck, but the functional relevance of this interaction remains unknown. Here, we demonstrate that T cell receptor and CD4 coligation on human T cells results in enhanced association between Cbl and Lck, together with Lck ubiquitination and degradation. A Cbl(-/-) T cell line showed a marked deficiency in Lck ubiquitination and increased levels of kinase-active Lck. Coexpression in 293T cells demonstrated that Lck kinase activity and Cbl ubiquitin ligase activity were essential for Lck ubiquitination and negative regulation of Lck-dependent serum response element-luciferase reporter activity. The Lck SH3 domain was pivotal for Cbl-Lck association and Cbl-mediated Lck degradation, with a smaller role for interactions mediated by the Cbl tyrosine kinase-binding domain. Finally, analysis of a ZAP-70-deficient T cell line revealed that Cbl inhibited Lck-dependent mitogen-activated protein kinase activation, and an intact Cbl RING finger domain was required for this functional effect. Our results demonstrate a direct, ubiquitination-dependent, negative regulatory role of Cbl for Lck in T cells, independent of Cbl-mediated regulation of ZAP-70.

CD4 Antigens↗
PubMed2002

Functionally distinct subsets of CD1d-restricted natural killer T cells revealed by CD1d tetramer staining.

CD1d-restricted natural killer (NK)T cells are known to potently secrete T helper (Th)1 and Th2 cytokines and to mediate cytolysis, but it is unclear how these contrasting functional activities are regulated. Using lipid antigen-loaded CD1d tetramers, we have distinguished two subsets of CD1d-restricted T cells in fresh peripheral blood that differ in cytokine production and cytotoxic activation. One subset, which was CD4(-), selectively produced the Th1 cytokines interferon gamma and tumor necrosis factor alpha, and expressed NKG2d, a marker associated with cytolysis of microbially infected and neoplastic cells. This subset up-regulated perforin after exposure to interleukin (IL)-2 or IL-12. In contrast, CD4(+) CD1d-restricted NKT cells potently produced both Th1 and Th2 cytokines, up-regulated perforin in response to stimulation by phorbol myristate acetate and ionomycin but not IL-2 or IL-12, and could be induced to express CD95L. Further, for both CD1d-restricted NKT cell subsets, we found that antigenic stimulation induced cytokine production but not perforin expression, whereas exposure to inflammatory factors enhanced perforin expression but did not stimulate cytokine production. These results show that the various activities of CD1d-restricted T cells in tumor rejection, autoimmune disease, and microbial infections could result from activation of functionally distinct subsets, and that inflammatory and antigenic stimuli may influence different effector functions.

Animals↗
PubMed2002

New cyclooxygenase-2 inhibitors for treatment of experimental autoimmune neuritis.

We analyzed two new cyclooxygenase-2 (COX-2) inhibitors, celecoxib (SC-58635) and meloxicam, for the treatment of experimental autoimmune neuritis (EAN) in rats. Celecoxib and meloxicam significantly reduced clinical EAN score and histopathological damage of the sciatic nerve. They induced no serious side effects, whereas indomethacin used as a control caused severe intestinal ulceration and dysfunction of liver and kidney. These findings suggest that the new COX-2 inhibitors may be useful as additional therapeutic agents for patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy.

Animals↗