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Fang Z, Feng X, Xu X, Zhou X, Lin Z, Ji Y. Investigation into outdoor thermal comfort conditions by different seasonal field surveys in China, Guangzhou. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2019; 63:1357-1368. [PMID: 31302762 DOI: 10.1007/s00484-019-01752-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 06/13/2019] [Accepted: 06/27/2019] [Indexed: 06/10/2023]
Abstract
Outdoor microclimatic conditions strongly affect the thermal comfort of pedestrians. A transversal field survey was conducted in Guangzhou, together with micrometeorological measurements. The outdoor physiological equivalent temperature (PET) varied from 3 to 59 °C. Regression lines were obtained to establish correlations of the mean thermal sensation vote (MTSV) with the PET bins with a width of 1 °C. Furthermore, the thermal comfort range of PET, neutral PET (NPET), and preferred PET was analyzed. The results indicated that, for the young people, thermal comfort range of PET spanned from 19.2 to 24.6 °C. The NPET and preferred PET significantly differed in different seasons. The NPET was higher in the summer than that in the winter and transitional seasons. However, the preferred PET of the summer was lower than that of the winter. The PET limits of different thermal stress categories were also confirmed, which differed from those in other cities. Thus, the impacts of adaptation on thermal comfort range were significant for people in outdoor environment.
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Zhu Q, Wang J, Zhang L, Bian W, Lin M, Xu X, Zhou X. LCK rs10914542-G allele associates with type 1 diabetes in children via T cell hyporesponsiveness. Pediatr Res 2019; 86:311-315. [PMID: 31112992 DOI: 10.1038/s41390-019-0436-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 12/24/2022]
Abstract
BACKGROUND Abnormal lymphocyte-specific protein tyrosine kinase (LCK)-related T cell hyporesponsiveness was discovered in type 1 diabetes (T1D). This study aims to investigate the potential associations between LCK single-nucleotide polymorphisms (SNPs) and the susceptibility of T1D. METHODS DNAs were extracted from blood samples of 589 T1D patients and 596 healthy controls to genotype seven SNPs of the LCK gene using PCR and Sanger sequencing. Associations of these SNPs with the susceptibility of T1D were determined by χ2 test. LCKs were knocked out in peripheral blood mononuclear cells (PBMCs) using CRISPR-Cas9 to investigate the role of LCK SNP in T-lymphocyte activation in T1D. RESULTS SNP rs10914542 but not the other six SNPs of the LCK gene was significantly associated with (C vs. G, odds ratio (OR) = 0.581, 95% confidence interval (CI) = 0.470-0.718, P value = 4.13E - 7) the susceptibility of T1D. Peripheral T-lymphocyte activation in response to T cell receptor (TCR)/CD3 stimulation is significantly lower in the rs10914542-G-allele group than in the C-allele group. In vitro experiments revealed that rs10914542 G allele impaired the TCR/CD3-mediated T-cell activation in PBMCs. CONCLUSIONS This study reveals that the G allele of SNP rs10914542 of LCK impairs the TCR/CD3-mediated T-cell activation and increases the risk of T1D.
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Xu X, Chen R, He F, Zhu L. Two non-radial measures of super-efficiency in DEA with data uncertainty. JOURNAL OF INTELLIGENT & FUZZY SYSTEMS 2017. [DOI: 10.3233/jifs-169217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Xu XN, Liu HY. [Clinical analysis of cervical posterior internal fixation titanium plate and silk suspension internal fixation cervical spondylosis]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 2017; 55:214-219. [PMID: 28241724 DOI: 10.3760/cma.j.issn.0529-5815.2017.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To evaluate the clinical effect and imaging evaluation of cervical spine myelopathy treated with Centerpiece. Methods: A retrospective study of 60 patients underwent posterior cervical spine surgery because of cervical myelopathy in Spinal Department of Peking University People's Hospital from July 2011 to January 2013.According to the different fixation methods, all patients were divided into cervical posterior open-door Centerpiece fixation group (group A) and cervical posterior open-door silk suspension fixation group (group B). There were 40 patients in group A, including 25 males and 15 females, mean age (59.7±11.9) years old, average course of disease before surgery (53.6±61.5) months, average follow-up time (28.5±3.1) months after operation.There were 20 patients in group B, including 15 males and 5 females, mean age (58.3±9.6) years old, average course of disease before surgery (50.4±14.9) months, average follow-up time (28.3±1.9) months after operation.The operation time, intraoperative blood loss, postoperative drainage, preoperative and postoperative Japanese Orthopaedic Association(JOA) score, the neck disability index(NDI) score, visual analog scale (VAS) score, postoperative axial pain, C(5) nerve root palsy, postoperative "re-closing" and other related complications were observed.Imaging assessment projects include: before and after surgery of cervical curvature, range of motion(ROM), spinal anteroposterior diameter, spinal canal expansion rate, the whole spinal cord backward shift distance and area of the spinal canal and the opening angle. Results: There was no significant difference in general data between the two groups (P>0.05). Group A the average operation time was(117.7±23.4)min, the average amount of operative bleeding was (152.0±122.7) ml, and the postoperative drainage volume was (268.7±222.1) ml.The average operation time of group B was (141.7±23.9) min, the average amount of operative bleeding was (166.7±42.5) ml, and the postoperative drainage volume of group B was (255.3±47.0) ml.There was no significant difference between the two groups in the amount of operative bleeding and postoperative drainage volume (both P>0.05), the operation time between the two groups was statistically significant (P<0.05). At the end of the follow-up, the JOA score, NDI score, and VAS score were significantly improved (P<0.05) in both group A and group B and there was no significant difference between the two groups (P>0.05). C(5) nerve root paralysis was not occurred in both two groups after operation.There were 1 case of axial pain in the group A and 7 cases in the group B and there were significant differences between the two groups (P<0.05). The group A was not found "re-closing" during the follow-up and 12 patients of group B found to be "re-closing" phenomenon, there were statistically different between the two groups (P<0.05). Comparison of preoperative and postoperative, there were no significant differences in cervical curvature and ROM in both groups (P>0.05). Butthe spinal canal diameter and the vertebral canal area were statistically different after surgery (P<0.05). There was no statistical difference between the two groups of cervical curvature and ROM (P>0.05). There was no statistical difference between the two groups of spinal canal diameter, spinal canal area and spinal canal diameter enlargement rate(P>0.05). There was no statistical difference between the two groups of the whole spinal cord backward shift distance(P>0.05). There were significant differences between the two groups at the angle of the open door (P<0.05). Conclusion: Centerpiece cervical posterior titanium plate can achieve good clinical efficacy in the treatment of multi segmental spinal cervical spondylosis.
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Kaslow DC, Kalil J, Bloom D, Breghi G, Colucci AM, De Gregorio E, Madhavan G, Meier G, Seabrook R, Xu X. The role of vaccines and vaccine decision-making to achieve the goals of the Grand Convergence in public health. Vaccine 2016; 35 Suppl 1:A10-A15. [PMID: 28017438 DOI: 10.1016/j.vaccine.2016.10.088] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 09/11/2016] [Accepted: 10/21/2016] [Indexed: 11/25/2022]
Abstract
On 17 and 18 July 2015, a meeting in Siena jointly sponsored by ADITEC and GlaxoSmithKline (GSK) was held to review the goals of the Global Health 2035 Grand Convergence, to discuss current vaccine evaluation methods, and to determine the feasibility of reaching consensus on an assessment framework for comprehensively and accurately capturing the full benefits of vaccines. Through lectures and workshops, participants reached a consensus that Multi-Criteria-Decision-Analysis is a method suited to systematically account for the many variables needed to evaluate the broad benefits of vaccination, which include not only health system savings, but also societal benefits, including benefits to the family and increased productivity. Participants also agreed on a set of "core values" to be used in future assessments of vaccines for development and introduction. These values include measures of vaccine efficacy and safety, incident cases prevented per year, the results of cost-benefit analyses, preventable mortality, and the severity of the target disease. Agreement on this set of core assessment parameters has the potential to increase alignment between manufacturers, public health agencies, non-governmental organizations (NGOs), and policy makers (see Global Health 2035 Mission Grand Convergence [1]). The following sections capture the deliberations of a workshop (Working Group 4) chartered to: (1) review the list of 24 parameters selected from SMART vaccines (see the companion papers by Timmis et al. and Madhavan et al., respectively) to determine which represent factors (see Table 1) that should be taken into account when evaluating the role of vaccines in maximizing the success of the Global Health 2035 Grand Convergence; (2) develop 3-5 "core values" that should be taken into account when evaluating vaccines at various stages of development; and (3) determine how vaccines can best contribute to the Global Health 2035 Grand Convergence effort.
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Yang Y, Zhang P, Yang X, Xu X. Spatial and temporal dynamics of agricultural residue resources in the last 30 years in China. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2016; 34:1231-1240. [PMID: 27895284 DOI: 10.1177/0734242x16670001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The availability and distribution of biomass resources are important for the development of the bioenergy industry in a region. Biomass resources are abundant in China; however, the raw material is severely deficient, which makes the Chinese bioenergy industry an embarrassment and a contradiction. Unclear reserves and distribution and changing trends of biomass resources are the reason for this situation. A collection coefficient model of Chinese agricultural residue resources was established and the spatial and temporal pattern dynamics of agricultural residue resources in the last 30 years were analyzed. The results show that agricultural residue resources increased in stages from 1978 to 2011, including a rapid increase from 1978 to 1999, a significant fall from 2000 to 2004, and a slow increase from 2004 to 2011. Crops straw and livestock manure are the main ingredients of agricultural residue resources with proportions of 53-59% and 31-38%, respectively. However, the former has gradually decreased, while the latter is increasing. This mainly resulted from the strategic reorganization of the Chinese agriculture structure and the rapid development of large-scale livestock breeding and agricultural mechanization. Large regional differences existed in Chinese agricultural residue resources, and three distribution types formed, including resource-rich areas in North China, Northeast and Inner Mongolia, resource-limited areas in Central and Southwest China, and resource-poor areas along Northwest and Southeast coasts. This pattern is a reverse of the distributions of climatic conditions, water resources, economic development, human resources, and technological levels. Finally, it can be predicted that livestock manure and biomass conversion technology at low temperature will play increasingly significant roles in bioenergy industry development.
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Zhao XQ, Xu XN, Chen LY. Production of Enzymes from Marine Actinobacteria. ADVANCES IN FOOD AND NUTRITION RESEARCH 2016; 78:137-151. [PMID: 27452169 DOI: 10.1016/bs.afnr.2016.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Marine actinobacteria are well recognized for their capabilities to produce valuable natural products, which have great potential for applications in medical, agricultural, and fine chemical industries. In addition to producing unique enzymes responsible for biosynthesis of natural products, many marine actinobacteria also produce hydrolytic enzymes which are able to degrade various biopolymers, such as cellulose, xylan, and chitin. These enzymes are important to produce biofuels and biochemicals of interest from renewable biomass. In this chapter, the recent reports of novel enzymes produced by marine actinobacteria are reviewed, and advanced technologies that can be applied to search for novel marine enzymes as well as for improved enzyme production by marine actinobacteria are summarized, which include ribosome engineering, genome mining, as well as synthetic biology studies.
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Xu X, Gao C, Pei J, Wang K, Al-Barakati A. Continuous similarity search for evolving queries. Knowl Inf Syst 2015. [DOI: 10.1007/s10115-015-0892-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Huang G, Ling KV, Xu X, Liao Y. Generalized eigenvalue minimization for uncertain first-order plus time-delay processes. ISA TRANSACTIONS 2014; 53:141-149. [PMID: 24079460 DOI: 10.1016/j.isatra.2013.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 08/08/2013] [Accepted: 09/06/2013] [Indexed: 06/02/2023]
Abstract
This paper shows how to apply generalized eigenvalue minimization to processes that can be described by a first-order plus time-delay model with uncertain gain, time constant and delay. An algorithm to transform the uncertain first-order plus time delay model into a state-space model with uncertainty polyhedron is firstly described. The accuracy of the transformation is studied using numerical examples. Then, the uncertainty polyhedron is rewritten as a linear-matrix-inequality constraint and generalized eigenvalue minimization is adopted to calculate a feedback control law. Case studies show that even if uncertainties associated with the first-order plus time delay model are significant, a stable feedback control law can be found. The proposed control is tested by comparing with a robust internal model control. It is also tested by applying it to the temperature control of air-handing units.
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Zhou D, Zhang X, Li W, Xu X, Goonetilleke N, Yang H, Dong T, Yan H. Short communication: broader T cell responses directed against human immunodeficiency virus type 1 in infected Chinese individuals through blood-borne transmission in comparison with mucosal transmission. AIDS Res Hum Retroviruses 2013; 29:89-93. [PMID: 22650798 DOI: 10.1089/aid.2011.0314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cellular immune responses play a critical role in the control of human immunodeficiency virus type 1 (HIV-1), but less is known about the impact of transmission routes on immune defenses against HIV-1. Here, we report that subjects infected with HIV-1 through contaminated blood showed stronger HIV-specific T cell responses than those infected through mucosa, both in breadth (6.9±2.5 vs. 2.3±0.5, p=0.0293) and in magnitude [1270.0±544.9 vs. 409.5±121.3 SFU per million peripheral blood mononuclear cells (PBMCs), p=0.0223], by using a matrix of 404 overlapping peptides spanning all expressed HIV-1 proteins in an interferon (IFN)-γ enzyme-linked immunospot (ELISpot) assay. Our observation indicates that different mechanisms might be involved in the priming/generating of anti-HIV-specific T cell responses through different transmission routes.
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Perkins MR, Ryschkewitsch C, Liebner JC, Monaco MCG, Himelfarb D, Ireland S, Roque A, Edward HL, Jensen PN, Remington G, Abraham T, Abraham J, Greenberg B, Kaufman C, LaGanke C, Monson NL, Xu X, Frohman E, Major EO, Douek DC. Changes in JC virus-specific T cell responses during natalizumab treatment and in natalizumab-associated progressive multifocal leukoencephalopathy. PLoS Pathog 2012; 8:e1003014. [PMID: 23144619 PMCID: PMC3493478 DOI: 10.1371/journal.ppat.1003014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 09/20/2012] [Indexed: 12/24/2022] Open
Abstract
Progressive multifocal leukoencephalopathy (PML) induced by JC virus (JCV) is a risk for natalizumab-treated multiple sclerosis (MS) patients. Here we characterize the JCV-specific T cell responses in healthy donors and natalizumab-treated MS patients to reveal functional differences that may account for the development of natalizumab-associated PML. CD4 and CD8 T cell responses specific for all JCV proteins were readily identified in MS patients and healthy volunteers. The magnitude and quality of responses to JCV and cytomegalovirus (CMV) did not change from baseline through several months of natalizumab therapy. However, the frequency of T cells producing IL-10 upon mitogenic stimulation transiently increased after the first dose. In addition, MS patients with natalizumab-associated PML were distinguished from all other subjects in that they either had no detectable JCV-specific T cell response or had JCV-specific CD4 T cell responses uniquely dominated by IL-10 production. Additionally, IL-10 levels were higher in the CSF of individuals with recently diagnosed PML. Thus, natalizumab-treated MS patients with PML have absent or aberrant JCV-specific T cell responses compared with non-PML patients, and changes in T cell-mediated control of JCV replication may be a risk factor for developing PML. Our data suggest further approaches to improved monitoring, treatment and prevention of PML in natalizumab-treated patients. Progressive multifocal leukoencephalopathy (PML) is a complication of treatment with natalizumab in patients with multiple sclerosis (MS) and Crohn's disease. PML results from a failure of the immune system to control replication of JC virus (JCV) in the brain. We studied the T cell responses of 8 patients with MS who were starting treatment with natalizumab, 10 healthy volunteers, and 4 patients with natalizumab-associated PML. The magnitude and quality of JCV-specific immune responses remained unchanged after starting natalizumab. However, applying the same methods and antigens, we found that immune responses in the individuals who developed PML differed from those in the MS patients and healthy volunteers. In the four patients with PML from whom the laboratory had identified JCV DNA in the cerebrospinal fluid (CSF), two had no measurable T cell response to JCV and two had T cells that produced IL-10, an anti-inflammatory mediator. Furthermore, we studied the CSF of 10 patients with natalizumab-associated PML and 10 patients on natalizumab who had similar symptoms but did not have PML. We found that IL-10 was detectable in the CSF of half of the individuals with PML but none of the control group. These findings shed light on the mechanisms that lead to PML in a subset of patients treated with natalizumab and have implications for therapeutic and preventative measures.
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Jiao Y, Zhang T, Wang R, Zhang H, Huang X, Yin J, Zhang L, Xu X, Wu H. Plasma IP-10 Is Associated with Rapid Disease Progression in Early HIV-1 Infection. Viral Immunol 2012; 25:333-7. [PMID: 22788418 DOI: 10.1089/vim.2012.0011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Yang H, Wu H, Hancock G, Clutton G, Sande N, Xu X, Yan H, Huang X, Angus B, Kuldanek K, Fidler S, Denny TN, Birks J, McMichael A, Dorrell L. Antiviral inhibitory capacity of CD8+ T cells predicts the rate of CD4+ T-cell decline in HIV-1 infection. J Infect Dis 2012; 206:552-61. [PMID: 22711904 DOI: 10.1093/infdis/jis379] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Rare human immunodeficiency virus type 1 (HIV-1)-infected individuals who maintain control of viremia without therapy show potent CD8+ T-cell-mediated suppression of viral replication in vitro. Whether this is a determinant of the rate of disease progression in viremic individuals is unknown. METHODS We measured CD8+ T-cell-mediated inhibition of a heterologous HIV-1 isolate in 50 HIV-1-seropositive adults with diverse progression rates. Linear mixed models were used to determine whether CD8+ T-cell function could explain variation in the rate of CD4+ T-cell decline. RESULTS There was a significant interaction between CD8+ T-cell antiviral activity in vitro and the rate of CD4+ T-cell decline in chronically infected individuals (P < .0001). In a second prospective analysis of recently infected subjects followed for up to 3 years, CD8+ T-cell antiviral activity strongly predicted subsequent CD4+ T-cell decline (P < .0001) and explained up to 73% of the interindividual variation in the CD4+ T-cell slope. In addition, it was inversely associated with viral load set point (r = -0.68 and P = .002). CONCLUSIONS The antiviral inhibitory capacity of CD8+ T cells is highly predictive of CD4+ T-cell loss in early HIV-1 infection. It has potential as a benchmark of effective immunity in vaccine evaluation.
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Huang X, Li H, Liu Z, Guo C, Gao Y, Li Z, Fu Y, Zhang T, Chen D, Xu X, Wu H. PP-146 Incidence and characterization of acute HIV-1 infection among high-risk self-identified men who have sex with men in Beijing, China. Int J Infect Dis 2009. [DOI: 10.1016/s1201-9712(09)60540-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Zhang P, Zhou HF, Sun ZH, Shao XL, Zhang HT, Xu XN. [Cloning and tissue distribution analysis of CD1d in Rhesus macaque]. Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi 2009; 25:581-583. [PMID: 19737472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
AIM To amplify the CD1d and analyze its tissue distribution in Rhesus macaque. METHODS Extracting total RNA from different tissues of Rhesus macaque. CD1d amplification was carried using specific primers and tissue distribution was analyzed by semi-quantification RT-PCR, using the house-keeping gene GAPDH as an internal control. RESULTS The CD1d coding region was obtained in this experiment and tissue distribution was analyzed: a highest level of CD1d expression was detected in heart, liver and spleen, lower level in blood, lung, small intestine and stomach, and least in brain. CONCLUSION The successful amplification of CD1d is useful to produce anti-CD1d antibody and CD1d-tetramer to study NKT cells in Rhesus macaque. The expression profile of CD1d mRNA in Rhesus macaque is in accordance with the tissue distribution and the functions of NKT cells in other species. These results will provide important insights for future research on the relationship of CD1d/NKT cells and their roles in different tissues.
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Dejnirattisai W, Duangchinda T, Lin CLS, Vasanawathana S, Jones M, Jacobs M, Malasit P, Xu XN, Screaton G, Mongkolsapaya J. A complex interplay among virus, dendritic cells, T cells, and cytokines in dengue virus infections. THE JOURNAL OF IMMUNOLOGY 2009; 181:5865-74. [PMID: 18941175 DOI: 10.4049/jimmunol.181.9.5865] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Severe dengue virus (DV) infections can cause the life-threatening condition dengue hemorrhagic fever, which is characterized by a severe plasma leak, thrombocytopenia, hemorrhage, and, in severe cases, circulatory collapse and death. There is now much evidence that pre-existing immunity to DV can enhance disease when an individual becomes infected on a second or sequential occasion. It has been shown that in contrast to infected dendritic cells (DC), noninfected bystander DC underwent maturation in dengue infection. In this study, we show that TNF-alpha and type I IFN contribute to the maturation of bystander DC, whereas the inhibition of DV-infected DC maturation can be overcome by activated T cells. Furthermore, IFN-gamma-inducible chemokines, CXCL9, 10, and 11 produced by infected DC are greatly amplified in the presence of DV-specific T cells. The chemokine secretion is also enhanced in coculture of HUVEC with either DV-infected DC or activated T cells. Finally, we found a close correlation between the serum level of these three chemokines and disease severity.
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Xu XB, Fangohr H, Xu XN, Gu M, Wang ZH, Ji SM, Ding SY, Shi DQ, Dou SX. Peak effect in the critical current of type II superconductors with strong magnetic vortex pinning. PHYSICAL REVIEW LETTERS 2008; 101:147002. [PMID: 18851560 DOI: 10.1103/physrevlett.101.147002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Indexed: 05/26/2023]
Abstract
We perform 2D Langevin simulations studying the peak effect (PE) of the critical current taking into account the temperature dependence of the competing forces. We observe and report that the PE results from the competition of vortex-vortex interactions and vortex-pin interactions which have different temperature dependencies. The simulations reveal that the PE can take place only for certain pinning strengths, densities of pinning centers, and driving forces, which is in good agreement with experiments. No apparent vortex order-disorder transition is observed across the PE regime. In addition, the PE is a dynamical phenomenon, and thermal fluctuations can speed up the process for the formation of the PE.
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Chen Y, Chan VSF, Zheng B, Chan KYK, Xu X, To LYF, Huang FP, Khoo US, Lin CLS. A novel subset of putative stem/progenitor CD34+Oct-4+ cells is the major target for SARS coronavirus in human lung. ACTA ACUST UNITED AC 2007; 204:2529-36. [PMID: 17923501 PMCID: PMC2118498 DOI: 10.1084/jem.20070462] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Identification of the nature of severe acute respiratory syndrome (SARS)-infected cells is crucial toward understanding the pathogenesis. Using multicolor colocalization techniques, we previously reported that SARS+ cells in the lung of fatally infected patients expressed the only known functional receptor, angiotensin-converting enzyme 2, and also a binding receptor, liver/lymph node–specific ICAM-3–grabbing non-integrin (CD209L). In this study, we show that SARS-infected cells also express the stem/progenitor cell markers CD34 and Oct-4, and do not express cytokeratin or surfactant. These putative lung stem/progenitor cells can also be identified in some non-SARS individuals and can be infected by SARS-coronavirus ex vivo. Infection of these cells may contribute to the loss of lung repair capacity that leads to respiratory failure as clinically observed.
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Mongkolsapaya J, Duangchinda T, Dejnirattisai W, Vasanawathana S, Avirutnan P, Jairungsri A, Khemnu N, Tangthawornchaikul N, Chotiyarnwong P, Sae-Jang K, Koch M, Jones Y, McMichael A, Xu X, Malasit P, Screaton G. T Cell Responses in Dengue Hemorrhagic Fever: Are Cross-Reactive T Cells Suboptimal? THE JOURNAL OF IMMUNOLOGY 2006; 176:3821-9. [PMID: 16517753 DOI: 10.4049/jimmunol.176.6.3821] [Citation(s) in RCA: 209] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dengue virus infection poses a growing public health and economic burden in a number of tropical and subtropical countries. Dengue circulates as a number of quasispecies, which can be divided by serology into four groups or serotypes. An interesting feature of Dengue, recognized over five decades ago, is that most severe cases that show hemorrhagic fever are not suffering from a primary infection. Instead, they are reinfected with a virus of different serotype. This observation poses considerable problems in vaccine design, and it is therefore imperative to gain a full understanding of the mechanisms underlying this immunological enhancement of disease. In this study, we examined a T cell epitope restricted by HLA-A*24, a major MHC class I allele, in Southeast Asia in a cohort of children admitted to a hospital with acute Dengue infection. The cytokine profiles and the degranulation capacity of T cells generated to this epitope are defined and compared across different viral serotypes. Cross-reactive Dengue-specific T cells seem to show suboptimal degranulation but high cytokine production, which may contribute to the development of the vascular leak characteristic of Dengue hemorrhagic fever.
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Iversen AKN, Stewart-Jones G, Learn GH, Christie N, Sylvester-Hviid C, Armitage AE, Kaul R, Beattie T, Lee JK, Li Y, Chotiyarnwong P, Dong T, Xu X, Luscher MA, MacDonald K, Ullum H, Klarlund-Pedersen B, Skinhøj P, Fugger L, Buus S, Mullins JI, Jones EY, van der Merwe PA, McMichael AJ. Conflicting selective forces affect T cell receptor contacts in an immunodominant human immunodeficiency virus epitope. Nat Immunol 2006; 7:179-89. [PMID: 16388312 DOI: 10.1038/ni1298] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Accepted: 12/05/2005] [Indexed: 11/08/2022]
Abstract
Cytotoxic T lymphocytes (CTLs) are critical for the control of human immunodeficiency virus, but containment of virus replication can be undermined by mutations in CTL epitopes that lead to virus escape. We analyzed the evolution in vivo of an immunodominant, HLA-A2-restricted CTL epitope and found two principal, diametrically opposed evolutionary pathways that exclusively affect T cell-receptor contact residues. One pathway was characterized by acquisition of CTL escape mutations and the other by selection for wild-type amino acids. The pattern of CTL responses to epitope variants shaped which variant(s) prevailed in the virus population. The pathways notably influenced the amount of plasma virus, as patients with efficient CTL selection had lower plasma viral loads than did patients without efficient selection. Thus, viral escape from CTL responses does not necessarily correlate with disease progression.
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MESH Headings
- Adult
- Amino Acid Sequence
- Crystallography, X-Ray
- Evolution, Molecular
- Female
- Gene Products, gag/chemistry
- Gene Products, gag/genetics
- Gene Products, gag/immunology
- Genetic Variation
- HIV Antigens/genetics
- HIV Antigens/metabolism
- HIV Infections/immunology
- HIV Infections/virology
- HIV-1/genetics
- HIV-1/immunology
- HLA-A2 Antigen/chemistry
- HLA-A2 Antigen/metabolism
- Humans
- Immunodominant Epitopes/genetics
- Immunodominant Epitopes/metabolism
- Models, Molecular
- Molecular Sequence Data
- Multiprotein Complexes
- Mutation
- Peptide Fragments/chemistry
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Phylogeny
- Receptors, Antigen, T-Cell/metabolism
- Selection, Genetic
- T-Lymphocytes, Cytotoxic/immunology
- Viremia/immunology
- Viremia/virology
- env Gene Products, Human Immunodeficiency Virus
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Chan VSF, Chan KYK, Chen Y, Poon LLM, Cheung ANY, Zheng B, Chan KH, Mak W, Ngan HYS, Xu X, Screaton G, Tam PKH, Austyn JM, Chan LC, Yip SP, Peiris M, Khoo US, Lin CLS. Homozygous L-SIGN (CLEC4M) plays a protective role in SARS coronavirus infection. Nat Genet 2006; 38:38-46. [PMID: 16369534 PMCID: PMC7097088 DOI: 10.1038/ng1698] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Accepted: 10/03/2005] [Indexed: 12/22/2022]
Abstract
Severe acute respiratory syndrome (SARS) is caused by infection of a previously undescribed coronavirus (CoV). L-SIGN, encoded by CLEC4M (also known as CD209L), is a SARS-CoV binding receptor that has polymorphism in its extracellular neck region encoded by the tandem repeat domain in exon 4. Our genetic risk association study shows that individuals homozygous for CLEC4M tandem repeats are less susceptible to SARS infection. L-SIGN is expressed in both non-SARS and SARS-CoV-infected lung. Compared with cells heterozygous for L-SIGN, cells homozygous for L-SIGN show higher binding capacity for SARS-CoV, higher proteasome-dependent viral degradation and a lower capacity for trans infection. Thus, homozygosity for L-SIGN plays a protective role during SARS infection.
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Dong T, Stewart-Jones G, Chen N, Easterbrook P, Xu X, Papagno L, Appay V, Weekes M, Conlon C, Spina C, Little S, Screaton G, van der Merwe A, Richman DD, McMichael AJ, Jones EY, Rowland-Jones SL. HIV-specific cytotoxic T cells from long-term survivors select a unique T cell receptor. ACTA ACUST UNITED AC 2004; 200:1547-57. [PMID: 15596521 PMCID: PMC2212004 DOI: 10.1084/jem.20032044] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
HIV-specific cytotoxic T lymphocytes (CTL) are important in controlling HIV replication, but the magnitude of the CTL response does not predict clinical outcome. In four donors with delayed disease progression we identified Vβ13.2 T cell receptors (TCRs) with very similar and unusually long β-chain complementarity determining region 3 (CDR3) regions in CTL specific for the immunodominant human histocompatibility leukocyte antigens (HLA)-B8–restricted human immunodeficiency virus-1 (HIV-1) nef epitope, FLKEKGGL (FL8). CTL expressing Vβ13.2 TCRs tolerate naturally arising viral variants in the FL8 epitope that escape recognition by other CTL. In addition, they expand efficiently in vitro and are resistant to apoptosis, in contrast to FL8–specific CTL using other TCRs. Selection of Vβ13.2 TCRs by some patients early in the FL8-specific CTL response may be linked with better clinical outcome.
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Hu W, Yamasaki T, Feng Z, Yang BL, Xu XN, Wang JJ. Cloning and expressing of the three repeat fragments of Plasmodium falciparum 11.1 gene. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 2003; 19:15-8. [PMID: 12572016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To clone and express the 3R, 6R and 9R repeat fragments of Plasmodium falciparum(Pf11.1) gene. METHODS Three repeat fragments from the genomic DNA of Plasmodium falciparum 3D7 strain cultivated were amplified by using the designed primers. The PCR products were cloned into the pT7 vector for bi-direction sequencing. The sequencing results were analysised by GENETYX-MAC. And then the amplified fragments were subcloned into pET32a(+) or pET32b(+) in order to express the recombinant proteins under the induction of IPTG in E. coli BL21. RESULTS 3R,6R and 9R fragments with sizez of 552 bp, 630 bp and 444 bp respectively were successfully amplified by PCR. The sequence analysis showed that there were 4 more 3AA units and one more 6AA unit in Pf11.1 gene of 3D7 strain as compared with Palo Alto strain. The homologies of the nucleotide sequence between the 3R fragment and the 6R fragment of the two strains were 92.8% and 95.1%, respectively. The amplified 9R fragment contains 139AA repeat units. The three recombinant proteins were expressed in BL21 strain with molecular weights of 45, 60 and 42 kDa. CONCLUSION We got the 3R, 6R and 9R fragments separately by PCR and expressed them in E. coli successfully. The Pf11.1 gene of 3D7 strain is highly homologous to that of the Palo Alto strain.
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Mongkolsapaya J, Dejnirattisai W, Xu XN, Vasanawathana S, Tangthawornchaikul N, Chairunsri A, Sawasdivorn S, Duangchinda T, Dong T, Rowland-Jones S, Yenchitsomanus PT, McMichael A, Malasit P, Screaton G. Original antigenic sin and apoptosis in the pathogenesis of dengue hemorrhagic fever. Nat Med 2003; 9:921-7. [PMID: 12808447 DOI: 10.1038/nm887] [Citation(s) in RCA: 603] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2003] [Accepted: 05/15/2003] [Indexed: 12/13/2022]
Abstract
Dengue virus presents a growing threat to public health in the developing world. Four major serotypes of dengue virus have been characterized, and epidemiological evidence shows that dengue hemorrhagic fever (DHF), the more serious manifestation of the disease, occurs more frequently upon reinfection with a second serotype. We have studied dengue virus-specific T-cell responses in Thai children. During acute infection, few dengue-responsive CD8+ T cells were recovered; most of those present showed an activated phenotype and were undergoing programmed cell death. Many dengue-specific T cells were of low affinity for the infecting virus and showed higher affinity for other, probably previously encountered strains. Profound T-cell activation and death may contribute to the systemic disturbances leading to DHF, and original antigenic sin in the T-cell responses may suppress or delay viral elimination, leading to higher viral loads and increased immunopathology.
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Abstract
Many viruses establish life-long infections in their natural host with few if any clinical manifestations. The relationship between virus and host is a dynamic process in which the virus has evolved the means to coexist by reducing its visibility, while the host immune system attempts to suppress and eliminate infection without damage to itself. This short review describes a variety of strategies that are employed by viruses to evade host immune responses. These include virus-associated escape from T cell recognition, and resistance to apoptosis and counterattack, with special reference to two papers published in this issue of Immunity (Mueller et al., 2001; Raftery et al., 2001).
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