423 research outputs found
Relic abundance of dark matter in the minimal universal extra dimension model
We investigate the relic abundance of dark matter in the minimal universal
extra dimension model including resonance processes by second Kaluza-Klein (KK)
particles in all coannihilation processes. After including second KK resonance
processes, the relic abundance of dark matter is reduced by about 30%. Thus,
the compactification scale 1/R of the extra dimension consistent with the WMAP
observation is increased by a few hundred GeV. As a result, the cosmologically
allowed compactification scale is 600 GeV < 1/R < 1400 GeV for Lambda R = 20.Comment: 24 pages, 7 figure
1-Diazonaphthalen-2(1H)-one
The molecule of the title compound, C10H6N2O, is nearly planar [maximum deviation = 0.030 (1) Å]. The CN2 moiety is almost linear, with a C—N—N angle of 175.50 (14)°. A single intermolecular C—H⋯O hydrogen bond is observed in the crystal structure. A π–π interaction is also observed with the shortest distance being 3.6832 (12) Å between the the centroids of the six-membered rings
Role of TNF Ligand and Receptor Family in the Lymphoid Organogenesis Defined by Gene Targeting
The molecular basis of lymphoid organogenesis has recently been elucidated using gene-targeted mice. Mice deficient in lymphotoxin-α (LTα) lack lymph nodes and Peyer's patches. The action of LTα in lymphoid organogenesis is mediated mostly by the membrane form of LT by a mechanism independent of TNF receptor I (TNFR-I) or II (TNFR-II). Additionally, follicular dendritic cell (FDC) clusters or germinal centers fail to develop in the spleen of LTα-deficient mice. Mice deficient in either TNFR-I or LTβR also fail to develop splenic FDC clusters and germinal centers, indicating that signaling through both TNFR-I and LTβR is required for the development of these structures. The mechanisms underlying the defective lymphoid organogenesis in LTα-deficient mice, together with a natural mutant strain, alymphoplasia (aly) mice, which manifest a quite similar phenotype to LTα-deficient mice, were investigated by generating aggregation chimeras. These studies demonstrate that LTα and the aly gene product together control lymphoid organogenesis with a close mechanistic relationship in their biochemical pathways through governing distinct cellular compartments;the former acting as a circulating ligand and the latter as a LTβR-signaling molecule expressed by the stroma of the lymphoid organs
Revisiting Aire and tissue-restricted antigens at single-cell resolution
The thymus is a highly specialized organ that plays an indispensable role in the establishment of self-tolerance, a process characterized by the “education” of developing T-cells. To provide competent T-cells tolerant to self-antigens, medullary thymic epithelial cells (mTECs) orchestrate negative selection by ectopically expressing a wide range of genes, including various tissue-restricted antigens (TRAs). Notably, recent advancements in the high-throughput single-cell analysis have revealed remarkable heterogeneity in mTECs, giving us important clues for dissecting the mechanisms underlying TRA expression. We overview how recent single-cell studies have furthered our understanding of mTECs, with a focus on the role of Aire in inducing mTEC heterogeneity to encompass TRAs
PHENOTYPIC ANALYSIS OF MICE DEFICIENT FOR Ly6C1/Ly6C2
Ly6C comprises two homologous components of Ly6C1 and Ly6C2, and the expression of either of the Ly6C molecules defines unique functional subsets of monocytes. Ly6C is also expressed by other immune cell types, including Aire-expressing medullary thymic epithelial cells. Because the role of Ly6C expression in determining the functional subsets remains unclear, we generated mice deficient for both Ly6C1 and Ly6C2 with CRISPR-Cas9–mediated deletion. Mice deficient for Ly6C1/Ly6C2 showed no major alterations in the subsets and function of monocyte and other immune cells, including the cells involved in the dextran sulfate sodium salt–induced colitis model. By generating the mice deficient for Ly6C1 alone, we have also investigated the expression pattern of Ly6C1 and Ly6C2 in immune cells. Except for medullary thymic epithelial cells and CD4 single-positive T cells, immune cells predominantly expressed Ly6C2. Thus, despite the importance as a marker with a unique differential expression pattern, the Ly6C molecules have no major impact on determining the functional subsets and maintaining immune homeostasis
Aire suppresses CTLA-4 expression from the thymic stroma to control autoimmunity
Impaired production of thymic regulatory T cells (Tregs) is implicated in the development of Aire-dependent autoimmunity. Because Tregs require agonistic T cell receptor stimuli by self-antigens to develop, reduced expression of self-antigens from medullary thymic epithelial cells (mTECs) has been considered to play a major role in the reduced Treg production in Aire deficiency. Here, we show that mTECs abnormally express co-inhibitory receptor CTLA-4 if Aire is non-functional. Upon binding with CD80/CD86 ligands expressed on thymic dendritic cells (DCs), the ectopically expressed CTLA-4 from Aire-deficient mTECs removes the CD80/CD86 ligands from the DCs. This attenuates the ability of DCs to provide co-stimulatory signals and to present self-antigens transferred from mTECs, both of which are required for Treg production. Accordingly, impaired production of Tregs and organ-specific autoimmunity in Aire-deficient mice are rescued by the depletion of CTLA-4 expression from mTECs. Our studies illuminate the significance of mTEC-DC interaction coordinated by Aire for the establishment of thymic tolerance
Amelioration of diabetes in NOD by additive Aire
Tissue-specific autoimmune diseases are assumed to arise through malfunction of two checkpoints for immune tolerance: defective elimination of autoreactive T cells in the thymus and activation of these T cells by corresponding autoantigens in the periphery. However, evidence for this model and the outcome of such alterations in each or both of the tolerance mechanisms have not been sufficiently investigated. We studied these issues by expressing human AIRE (huAIRE) as a modifier of tolerance function in NOD mice wherein the defects of thymic and peripheral tolerance together cause type I diabetes (T1D). Additive huAIRE expression in the thymic stroma had no major impact on the production of diabetogenic T cells in the thymus. In contrast, huAIRE expression in peripheral antigen-presenting cells (APCs) rendered the mice resistant to T1D, while maintaining other tissue-specific autoimmune responses and antibody production against an exogenous protein antigen, because of the loss of Xcr1+ dendritic cells, an essential component for activating diabetogenic T cells in the periphery. These results contrast with our recent demonstration that huAIRE expression in both the thymic stroma and peripheral APCs resulted in the paradoxical development of muscle-specific autoimmunity. Our results reveal that tissue-specific autoimmunity is differentially controlled by a combination of thymic function and peripheral tolerance, which can be manipulated by expression of huAIRE/Aire in each or both of the tolerance mechanisms
Expression Profile of Intravitreous Cytokines, Chemokines and Growth Factors in Patients with Fuchs Heterochromic Iridocyclitis
Purpose: To report the postoperative courses of 2 patients with Fuchs heterochromic iridocyclitis (FHI) and the concentrations of various cytokines, chemokines and growth factors in vitreous fluid samples to obtain insights into pathobiochemical aspects. Subjects: The patients were a 27- and a 47-year-old woman. Phacoemulsification and aspiration, intraocular lens (IOL) implantation, and pars plana vitrectomy were performed to treat their cataracts and vitreous opacities. During their early postoperative periods, inflammatory cells precipitated on the IOL and intraocular pressure was increased in both patients. Methods: At the time of surgery, undiluted vitreous fluid specimens were collected. The concentrations of multiple cytokines, chemokines and growth factors were measured by a bead array immunodetection system. Results: The levels of interleukin-1ra, -5, -6, -8, -10 and -13, interferon-inducible 10-kDa protein, monocyte chemoattractant protein 1, macrophage inflammatory protein 1β, and regulated upon activation, normal T-cell expressed and secreted (RANTES) were significantly elevated in vitreous fluid in both patients. Conclusion: Although the postoperative course was generally favorable in patients with FHI, steroid instillation was necessary for a few months postoperatively, as precipitates easily formed on the IOL surface and elevated intraocular pressure. The profiles of intravitreal concentrations of cytokines, chemokines and growth factors may characterize postoperative inflammatory reactions
X-Ray Fluctuations from Locally Unstable Advection-Dominated Disks
The response of advection-dominated accretion disks to local disturbances is
examined by one-dimensional numerical simulations. It is generally believed
that advection-dominated disks are thermally stable. We, however, find that any
disurbance added onto accretion flow at large radii does not decay so rapidly
that it can move inward with roughly the free-fall velocity. Although
disturbances continue to be present, the global disk structure will not be
modified largely. This can account for persistent hard X-ray emission with
substantial variations observed in active galactic nuclei and stellar black
hole candidates during the hard state. Moreover, when the disturbance reaches
the innermost parts, an acoustic wave emerges, propagating outward as a shock
wave. The resultant light variation is roughly (time) symmetric and is quite
reminiscent of the observed X-ray shots of Cygnus X-1.Comment: plain TeX, 11 pages, without figures; to be published in ApJ Lette
Current Insights into Atopic March
The incidence of allergic diseases is increasing, and research on their epidemiology, pathophysiology, and the prevention of onset is urgently needed. The onset of allergic disease begins in infancy with atopic dermatitis and food allergy and develops into allergic asthma and allergic rhinitis in childhood; the process is defined as "atopic march ". Atopic march is caused by multiple immunological pathways, including allergen exposure, environmental pollutants, skin barrier dysfunction, type 2 inflammation, and oxidative stress, which promote the progression of atopic march. Using recent evidence, herein, we explain the involvement of allergic inflammatory conditions and oxidative stress in the process of atopic march, its epidemiology, and methods for prevention of onset
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