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Lochbihler K, Lenderink G, Siebesma AP. Cold Pool Dynamics Shape the Response of Extreme Rainfall Events to Climate Change. JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2021; 13:e2020MS002306. [PMID: 35865618 PMCID: PMC9285889 DOI: 10.1029/2020ms002306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 06/15/2023]
Abstract
There is increasing evidence that local rainfall extremes can increase with warming at a higher rate than expected from the Clausius-Clapeyron (CC) relation. The exact mechanisms behind this super-CC scaling phenomenon are still unsolved. Recent studies highlight invigorated local dynamics as a contributor to enhanced precipitation rates with warming. Here, cold pools play an important role in the process of organization and deepening of convective clouds. Another known effect of cold pools is the amplification of low-level moisture variability. Yet, how these processes respond to climatic warming and how they relate to enhanced precipitation rates remains largely unanswered. Unlike other studies which use rather simple approaches mimicking climate change, we present a much more comprehensive set of experiments using a high-resolution large eddy simulation (LES) model. We use an idealized but realistically forced case setup, representative for conditions with extreme summer precipitation in midlatitudes. Based on that, we examine how a warmer atmosphere under the assumption of constant and varying relative humidity, lapse rate changes and enhanced large-scale dynamics influence precipitation rates, cold pool dynamics, and the low-level moisture field. Warmer conditions generally lead to larger and more intense events, accompanied by enhanced cold pool dynamics and a concurring moisture accumulation in confined regions. The latter are known as preferred locations for new convective events. Our results show that cold pool dynamics play an increasingly important role in shaping the response of local precipitation extremes to global warming, providing a potential mechanism for super-CC behavior as subject for future research.
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Affiliation(s)
- Kai Lochbihler
- The Royal Netherlands Meteorological Institute (KNMI)De BiltThe Netherlands
- Delft University of TechnologyDelftThe Netherlands
| | - Geert Lenderink
- The Royal Netherlands Meteorological Institute (KNMI)De BiltThe Netherlands
| | - A. Pier Siebesma
- The Royal Netherlands Meteorological Institute (KNMI)De BiltThe Netherlands
- Delft University of TechnologyDelftThe Netherlands
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2
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Santer BD, Po-Chedley S, Zelinka MD, Cvijanovic I, Bonfils C, Durack PJ, Fu Q, Kiehl J, Mears C, Painter J, Pallotta G, Solomon S, Wentz FJ, Zou CZ. Human influence on the seasonal cycle of tropospheric temperature. Science 2018; 361:361/6399/eaas8806. [PMID: 30026201 DOI: 10.1126/science.aas8806] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 06/07/2018] [Indexed: 11/02/2022]
Abstract
We provide scientific evidence that a human-caused signal in the seasonal cycle of tropospheric temperature has emerged from the background noise of natural variability. Satellite data and the anthropogenic "fingerprint" predicted by climate models show common large-scale changes in geographical patterns of seasonal cycle amplitude. These common features include increases in amplitude at mid-latitudes in both hemispheres, amplitude decreases at high latitudes in the Southern Hemisphere, and small changes in the tropics. Simple physical mechanisms explain these features. The model fingerprint of seasonal cycle changes is identifiable with high statistical confidence in five out of six satellite temperature datasets. Our results suggest that attribution studies with the changing seasonal cycle provide powerful evidence for a significant human effect on Earth's climate.
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Affiliation(s)
- Benjamin D Santer
- Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
| | - Stephen Po-Chedley
- Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Mark D Zelinka
- Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Ivana Cvijanovic
- Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Céline Bonfils
- Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Paul J Durack
- Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Qiang Fu
- Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195, USA
| | - Jeffrey Kiehl
- Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, USA
| | - Carl Mears
- Remote Sensing Systems, Santa Rosa, CA 95401, USA
| | - Jeffrey Painter
- Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Giuliana Pallotta
- Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Susan Solomon
- Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Cheng-Zhi Zou
- Center for Satellite Applications and Research, NOAA/NESDIS, College Park, MD 20740, USA
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3
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Holt MP, Punkosdy GA, Glass DD, Shevach EM. TCR Signaling and CD28/CTLA-4 Signaling Cooperatively Modulate T Regulatory Cell Homeostasis. THE JOURNAL OF IMMUNOLOGY 2017; 198:1503-1511. [PMID: 28053234 DOI: 10.4049/jimmunol.1601670] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 12/04/2016] [Indexed: 12/16/2022]
Abstract
Foxp3+ T regulatory cells (Tregs), conventional CD4+Foxp3- T cells, and CD8+ T cells represent heterogeneous populations composed of naive phenotype (NP, CD44low) and memory phenotype (MP, CD44high) subpopulations. NP and MP subsets differ in their activation state, contribution to immune function, and capacity to proliferate in vivo. To further understand the factors that contribute to the differential homeostasis of NP/MP subsets, we examined the differential effects of CD28 and CTLA-4 interaction with CD80/CD86, as well as MHC class II-TCR interaction within mouse Treg pools and CD4+ and CD8+ T cell pools. Blockade of CD80/CD86 with CTLA-4-Ig markedly reduced the cycling and absolute numbers of MP Tregs and MP CD4+ T cells, with minimal effect on the NP T cell subpopulations. Blockade of MHC class II-TCR interaction led to selective expansion of MP Tregs and MP CD4+ and CD8+ T cells that was reversed upon cotreatment with CTLA-4-Ig. Treatment with anti-CTLA-4 mAb altered MP Treg and MP CD4+ and CD8+ T cell homeostasis in a manner similar to that observed with anti-MHC class II. We postulate a complex pathway in which CD28 is the primary driver of Treg proliferation and CTLA-4 functions as the main brake but is likely dependent on TCR signals and CD80/CD86. These findings have important implications for the use of biologic agents targeting such pathways to modulate autoimmune and neoplastic disease.
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Affiliation(s)
- Michael P Holt
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - George A Punkosdy
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322; and.,Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
| | - Deborah D Glass
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Ethan M Shevach
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
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4
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Chu C, Wang Y, Zhang X, Ni X, Cao J, Xu W, Dong Z, Yuan P, Wei W, Ma Y, Zhang L, Wu L, Qi H. SAP-regulated T Cell-APC adhesion and ligation-dependent and -independent Ly108-CD3ζ interactions. THE JOURNAL OF IMMUNOLOGY 2014; 193:3860-71. [PMID: 25217164 DOI: 10.4049/jimmunol.1401660] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The germinal center response requires cooperation between Ag-specific T and B lymphocytes, which takes the form of long-lasting cell-cell conjugation in vivo. Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is required for stable cognate T-B cell conjugation, whereas SLAM family transmembrane (TM) receptor Ly108 may negatively regulate this process. We show that, other than phosphotyrosine-binding, SAP does not harbor motifs that recruit additional signaling intermediates to stabilize T-B adhesion. Ly108 dampens T cell adhesion to not only Ag-presenting B cells, but also dendritic cells by inhibiting CD3ζ phosphorylation through two levels of regulated Ly108-CD3ζ interactions. Constitutively associated with Src homology 2 domain-containing tyrosine phosphatase-1 even in SAP-competent cells, Ly108 is codistributed with the CD3 complex within a length scale of 100-200 nm on quiescent cells and can reduce CD3ζ phosphorylation in the absence of overt TCR stimulation or Ly108 ligation. When Ly108 is engaged in trans during cell-cell interactions, Ly108-CD3ζ interactions are promoted in a manner that uniquely depends on Ly108 TM domain, leading to more efficient CD3ζ dephosphorylation. Whereas replacement of the Ly108 TM domain still allows the constitutive, colocalization-dependent inhibition of CD3ζ phosphorylation, it abrogates the ligation-dependent Ly108-CD3ζ interactions and CD3ζ dephosphorylation, and it abolishes the suppression on Ag-triggered T-B adhesion. These results offer new insights into how SAP and Ly108 antagonistically modulate the strength of proximal TCR signaling and thereby control cognate T cell-APC interactions.
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Affiliation(s)
- Coco Chu
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yifeng Wang
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China
| | - Xu Zhang
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China
| | - Xinya Ni
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China
| | - Junxia Cao
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China
| | - Wan Xu
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China
| | - Zhongjun Dong
- Laboratory of Tumor Immunology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China
| | - Pengfei Yuan
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China; and
| | - Wensheng Wei
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China; and
| | - Yuanwu Ma
- Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medical Center, Peking Union Medical College, Beijing 100021, People's Republic of China
| | - Lianfeng Zhang
- Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medical Center, Peking Union Medical College, Beijing 100021, People's Republic of China
| | - Longyan Wu
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China
| | - Hai Qi
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, People's Republic of China;
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5
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Vudattu NK, Waldron-Lynch F, Truman LA, Deng S, Preston-Hurlburt P, Torres R, Raycroft MT, Mamula MJ, Herold KC. Humanized mice as a model for aberrant responses in human T cell immunotherapy. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 193:587-96. [PMID: 24943216 PMCID: PMC4123131 DOI: 10.4049/jimmunol.1302455] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Immune-deficient mice, reconstituted with human stem cells, have been used to analyze human immune responses in vivo. Although they have been used to study immune responses to xenografts, allografts, and pathogens, there have not been models of autoimmune disease in which the mechanisms of the pathologic process can be analyzed. We have found that reconstituted "humanized" mice treated with anti-CTLA-4 Ab (ipilimumab) develop autoimmune disease characterized by hepatitis, adrenalitis, sialitis, anti-nuclear Abs, and weight loss. Induction of autoimmunity involved activation of T cells and cytokine production, and increased infiltration of APCs. When anti-CTLA-4 mAb-treated mice were cotreated with anti-CD3 mAb (teplizumab), hepatitis and anti-nuclear Abs were no longer seen and weight loss did not occur. The anti-CD3 blocked proliferation and activation of T cells, release of IFN-γ and TNF, macrophage infiltration, and release of IP-10 that was induced with anti-CTLA-4 mAb. We also found increased levels of T regulatory cells (CD25(+)CD127(-)) in the spleen and mesenteric lymph nodes in the mice treated with both Abs and greater constitutive phosphorylation of STAT5 in T regulatory cells in spleen cells compared with mice treated with anti-CTLA-4 mAb alone. We describe a model of human autoimmune disease in vivo. Humanized mice may be useful for understanding the mechanisms of biologics that are used in patients. Hepatitis, lymphadenopathy, and other inflammatory sequelae are adverse effects of ipilimumab treatment in humans, and this study may provide insights into this pathogenesis and the effects of immunologics on autoimmunity.
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MESH Headings
- Adrenal Glands/drug effects
- Adrenal Glands/immunology
- Adrenal Glands/metabolism
- Animals
- Antibodies, Monoclonal/toxicity
- Antibodies, Monoclonal, Humanized/pharmacology
- Autoimmune Diseases/chemically induced
- Autoimmune Diseases/immunology
- Autoimmune Diseases/therapy
- Cytokines/blood
- Cytokines/immunology
- Cytokines/metabolism
- Disease Models, Animal
- Flow Cytometry
- Humans
- Interleukin Receptor Common gamma Subunit/deficiency
- Interleukin Receptor Common gamma Subunit/genetics
- Ipilimumab
- Liver/drug effects
- Liver/immunology
- Liver/metabolism
- Lymphocyte Activation/drug effects
- Lymphocyte Activation/immunology
- Macrophages/drug effects
- Macrophages/immunology
- Macrophages/metabolism
- Mice
- Mice, Inbred NOD
- Mice, Knockout
- Mice, SCID
- Phosphorylation/drug effects
- Phosphorylation/immunology
- STAT5 Transcription Factor/immunology
- STAT5 Transcription Factor/metabolism
- Stem Cell Transplantation/methods
- Survival Analysis
- T-Lymphocytes/drug effects
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- T-Lymphocytes, Regulatory/drug effects
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- Transplantation, Heterologous
- Weight Loss/drug effects
- Weight Loss/immunology
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Affiliation(s)
- Nalini K Vudattu
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520
| | - Frank Waldron-Lynch
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520
| | - Lucy A Truman
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520
| | - Songyan Deng
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520
| | | | - Richard Torres
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520; and
| | - Maurice T Raycroft
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Mark J Mamula
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Kevan C Herold
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520; Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
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6
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Human and natural influences on the changing thermal structure of the atmosphere. Proc Natl Acad Sci U S A 2013; 110:17235-40. [PMID: 24043789 DOI: 10.1073/pnas.1305332110] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Since the late 1970s, satellite-based instruments have monitored global changes in atmospheric temperature. These measurements reveal multidecadal tropospheric warming and stratospheric cooling, punctuated by short-term volcanic signals of reverse sign. Similar long- and short-term temperature signals occur in model simulations driven by human-caused changes in atmospheric composition and natural variations in volcanic aerosols. Most previous comparisons of modeled and observed atmospheric temperature changes have used results from individual models and individual observational records. In contrast, we rely on a large multimodel archive and multiple observational datasets. We show that a human-caused latitude/altitude pattern of atmospheric temperature change can be identified with high statistical confidence in satellite data. Results are robust to current uncertainties in models and observations. Virtually all previous research in this area has attempted to discriminate an anthropogenic signal from internal variability. Here, we present evidence that a human-caused signal can also be identified relative to the larger "total" natural variability arising from sources internal to the climate system, solar irradiance changes, and volcanic forcing. Consistent signal identification occurs because both internal and total natural variability (as simulated by state-of-the-art models) cannot produce sustained global-scale tropospheric warming and stratospheric cooling. Our results provide clear evidence for a discernible human influence on the thermal structure of the atmosphere.
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7
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Stumpf M, Zhou X, Bluestone JA. The B7-independent isoform of CTLA-4 functions to regulate autoimmune diabetes. THE JOURNAL OF IMMUNOLOGY 2013; 190:961-9. [PMID: 23293354 DOI: 10.4049/jimmunol.1201362] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The critical role of CTLA-4 in inhibiting Ag-driven T cell responses upon engagement with its ligands, B7-1 and B7-2 and its importance for peripheral T cell tolerance and T cell homeostasis has been studied intensively. The CTLA-4 splice variant ligand-independent (li)-CTLA-4 is expressed in naive and activated T cells and can actively alter T cell signaling despite its lack of a B7 binding domain. To study the effect of li-CTLA-4 in regulating T cell responses in the context of autoimmunity, we engineered a B6.CTLA-4 (floxed-Exon2)-BAC-transgene, resulting in selective expression of li-CTLA-4 upon Cre-mediated deletion of Exon 2. Introducing the B6.BAC into the NOD background, which is genetically deficient for li-CTLA-4, restores mRNA levels of li-CTLA-4 to those observed in C57BL/6 mice. Furthermore, re-expressing this ligand nonbinding isoform in NOD mice reduced IFN-γ production in T effector cells accompanied by a significant decrease in insulitis and type 1 diabetes frequency. However, selective expression of li-CTLA-4 could not fully rescue the CTLA-4 knockout disease phenotype when bred onto NOD.BDC2.5.CTLA-4 knockout background because of the requirement of the full-length, B7-binding CTLA-4 molecule on T effector cells. Thus, the li-CTLA-4 form, when expressed at physiologic levels in the CTLA-4-sufficient NOD background can suppress autoimmunity; however, the functionality of the li-CTLA-4 isoform depends on the presence of the full-length molecule to alter effector T cell signaling.
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Affiliation(s)
- Melanie Stumpf
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
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8
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Abstract
We perform a multimodel detection and attribution study with climate model simulation output and satellite-based measurements of tropospheric and stratospheric temperature change. We use simulation output from 20 climate models participating in phase 5 of the Coupled Model Intercomparison Project. This multimodel archive provides estimates of the signal pattern in response to combined anthropogenic and natural external forcing (the fingerprint) and the noise of internally generated variability. Using these estimates, we calculate signal-to-noise (S/N) ratios to quantify the strength of the fingerprint in the observations relative to fingerprint strength in natural climate noise. For changes in lower stratospheric temperature between 1979 and 2011, S/N ratios vary from 26 to 36, depending on the choice of observational dataset. In the lower troposphere, the fingerprint strength in observations is smaller, but S/N ratios are still significant at the 1% level or better, and range from three to eight. We find no evidence that these ratios are spuriously inflated by model variability errors. After removing all global mean signals, model fingerprints remain identifiable in 70% of the tests involving tropospheric temperature changes. Despite such agreement in the large-scale features of model and observed geographical patterns of atmospheric temperature change, most models do not replicate the size of the observed changes. On average, the models analyzed underestimate the observed cooling of the lower stratosphere and overestimate the warming of the troposphere. Although the precise causes of such differences are unclear, model biases in lower stratospheric temperature trends are likely to be reduced by more realistic treatment of stratospheric ozone depletion and volcanic aerosol forcing.
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Santer BD, Mears C, Doutriaux C, Caldwell P, Gleckler PJ, Wigley TML, Solomon S, Gillett NP, Ivanova D, Karl TR, Lanzante JR, Meehl GA, Stott PA, Taylor KE, Thorne PW, Wehner MF, Wentz FJ. Separating signal and noise in atmospheric temperature changes: The importance of timescale. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd016263] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- B. D. Santer
- Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory; Livermore California USA
| | - C. Mears
- Remote Sensing Systems; Santa Rosa California USA
| | - C. Doutriaux
- Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory; Livermore California USA
| | - P. Caldwell
- Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory; Livermore California USA
| | - P. J. Gleckler
- Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory; Livermore California USA
| | - T. M. L. Wigley
- National Center for Atmospheric Research; Boulder Colorado USA
| | - S. Solomon
- Department of Atmospheric and Oceanic Sciences; University of Colorado at Boulder; Boulder Colorado USA
| | - N. P. Gillett
- Canadian Centre for Climate Modelling and Analysis, Environment Canada; Victoria, British Columbia Canada
| | - D. Ivanova
- Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory; Livermore California USA
| | - T. R. Karl
- National Climatic Data Center, National Oceanic and Atmospheric Administration; Asheville North Carolina USA
| | - J. R. Lanzante
- Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration; Princeton New Jersey USA
| | - G. A. Meehl
- National Center for Atmospheric Research; Boulder Colorado USA
| | | | - K. E. Taylor
- Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory; Livermore California USA
| | - P. W. Thorne
- National Climatic Data Center, National Oceanic and Atmospheric Administration; Asheville North Carolina USA
| | - M. F. Wehner
- Lawrence Berkeley National Laboratory; Berkeley California USA
| | - F. J. Wentz
- Remote Sensing Systems; Santa Rosa California USA
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10
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Ribas A, Benz MR, Allen-Auerbach MS, Radu C, Chmielowski B, Seja E, Williams JL, Gomez-Navarro J, McCarthy T, Czernin J. Imaging of CTLA4 blockade-induced cell replication with (18)F-FLT PET in patients with advanced melanoma treated with tremelimumab. J Nucl Med 2010; 51:340-6. [PMID: 20150263 DOI: 10.2967/jnumed.109.070946] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Preclinical models predict that blockade of the coinhibitory molecule cytotoxic T lymphocyte-associated antigen 4 (CTLA4) on lymphocytes results in the release of a cell cycle inhibitory checkpoint, allowing lymphocyte proliferation, tumor targeting, and regression. However, there is a paucity of data demonstrating that lymphocyte proliferation does occur in humans treated with CTLA4-blocking antibodies. METHODS We tested the role of whole-body molecular imaging in patients with advanced melanoma receiving the CTLA4-blocking antibody tremelimumab, allowing the analysis of changes in glucose metabolism using the PET probe (18)F-FDG and cell replication with the PET probe 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT). RESULTS PET/CT scans obtained at a median of 2 mo after initial dosing did not demonstrate significant changes in lesion size or (18)F-FDG or (18)F-FLT uptake when focusing on metastatic lesions. Similarly, there was no difference in (18)F-FDG uptake in the non-melanoma-involved spleen. However, there were significant increases in standardized uptake values for (18)F-FLT in the spleen using post- and pretremelimumab treatment scans. CONCLUSION Molecular imaging with the PET probe (18)F-FLT allows mapping and noninvasive imaging of cell proliferation in secondary lymphoid organs after CTLA4 blockade in patients with metastatic melanoma.
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Affiliation(s)
- Antoni Ribas
- Division of Hematology/Oncology, Department of Medicine, UCLA, Los Angeles, California, USA.
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11
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Incorporating model quality information in climate change detection and attribution studies. Proc Natl Acad Sci U S A 2009; 106:14778-83. [PMID: 19706477 DOI: 10.1073/pnas.0901736106] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In a recent multimodel detection and attribution (D&A) study using the pooled results from 22 different climate models, the simulated "fingerprint" pattern of anthropogenically caused changes in water vapor was identifiable with high statistical confidence in satellite data. Each model received equal weight in the D&A analysis, despite large differences in the skill with which they simulate key aspects of observed climate. Here, we examine whether water vapor D&A results are sensitive to model quality. The "top 10" and "bottom 10" models are selected with three different sets of skill measures and two different ranking approaches. The entire D&A analysis is then repeated with each of these different sets of more or less skillful models. Our performance metrics include the ability to simulate the mean state, the annual cycle, and the variability associated with El Niño. We find that estimates of an anthropogenic water vapor fingerprint are insensitive to current model uncertainties, and are governed by basic physical processes that are well-represented in climate models. Because the fingerprint is both robust to current model uncertainties and dissimilar to the dominant noise patterns, our ability to identify an anthropogenic influence on observed multidecadal changes in water vapor is not affected by "screening" based on model quality.
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12
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Hoff H, Knieke K, Cabail Z, Hirseland H, Vratsanos G, Burmester GR, Jorch G, Nadler SG, Bröker B, Hebel K, Brunner-Weinzierl MC. Surface CD152 (CTLA-4) Expression and Signaling Dictates Longevity of CD28null T Cells. THE JOURNAL OF IMMUNOLOGY 2009; 182:5342-51. [DOI: 10.4049/jimmunol.0801624] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Xie F, Tian W, Chipperfield MP. Radiative effect of ozone change on stratosphere-troposphere exchange. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008jd009829] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Santer BD, Mears C, Wentz FJ, Taylor KE, Gleckler PJ, Wigley TML, Barnett TP, Boyle JS, Brüggemann W, Gillett NP, Klein SA, Meehl GA, Nozawa T, Pierce DW, Stott PA, Washington WM, Wehner MF. Identification of human-induced changes in atmospheric moisture content. Proc Natl Acad Sci U S A 2007; 104:15248-53. [PMID: 17881573 PMCID: PMC1986574 DOI: 10.1073/pnas.0702872104] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Indexed: 11/18/2022] Open
Abstract
Data from the satellite-based Special Sensor Microwave Imager (SSM/I) show that the total atmospheric moisture content over oceans has increased by 0.41 kg/m(2) per decade since 1988. Results from current climate models indicate that water vapor increases of this magnitude cannot be explained by climate noise alone. In a formal detection and attribution analysis using the pooled results from 22 different climate models, the simulated "fingerprint" pattern of anthropogenically caused changes in water vapor is identifiable with high statistical confidence in the SSM/I data. Experiments in which forcing factors are varied individually suggest that this fingerprint "match" is primarily due to human-caused increases in greenhouse gases and not to solar forcing or recovery from the eruption of Mount Pinatubo. Our findings provide preliminary evidence of an emerging anthropogenic signal in the moisture content of earth's atmosphere.
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Affiliation(s)
- B D Santer
- Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
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15
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Wei B, da Rocha Dias S, Wang H, Rudd CE. CTL-associated antigen-4 ligation induces rapid T cell polarization that depends on phosphatidylinositol 3-kinase, Vav-1, Cdc42, and myosin light chain kinase. THE JOURNAL OF IMMUNOLOGY 2007; 179:400-8. [PMID: 17579061 DOI: 10.4049/jimmunol.179.1.400] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CTLA-4 can negatively regulate cytokine production and proliferation, increase motility, and override the TCR-induced stop-signal needed for stable T cell-APC conjugation. Despite this, little is known regarding whether CTLA-4 can alter T cell morphology and the nature of the signaling events that could account for this event. In this study, we demonstrate that anti-CTLA-4 and CD3/CTLA-4 induce rapid T cell polarization (i.e., within 15-30 min) with increases in lamellipodia, filopodia, and uropod formation. This was observed with anti-CTLA-4 and CD80-Ig ligation of CTLA-4, but not with anti-CD3 alone, or anti-CD3/CD28 coligation. Polarization required PI3K, the guanine nucleotide exchange factor Vav1, the GTP-binding protein Cdc42, as well as myosin L chain kinase. By contrast, a key downstream target of PI3K, protein kinase B, as well as Rho kinase and RhoA, were not needed. Our results demonstrate that CTLA-4 is a potent activator T cell polarization needed for motility, and this process involves specific set of signaling proteins that might contribute to coreceptor regulation of T cell function.
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MESH Headings
- Animals
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, CD/physiology
- Antigens, Differentiation/immunology
- Antigens, Differentiation/metabolism
- Antigens, Differentiation/physiology
- CD3 Complex/immunology
- CTLA-4 Antigen
- Cell Movement/immunology
- Cells, Cultured
- Humans
- Immune Sera/physiology
- Intracellular Signaling Peptides and Proteins/metabolism
- Intracellular Signaling Peptides and Proteins/physiology
- Mice
- Myosin-Light-Chain Kinase/physiology
- Phosphatidylinositol 3-Kinases/physiology
- Protein Serine-Threonine Kinases/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Proto-Oncogene Proteins c-vav/physiology
- Pseudopodia/immunology
- T-Lymphocytes/cytology
- T-Lymphocytes/enzymology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- T-Lymphocytes, Cytotoxic/cytology
- T-Lymphocytes, Cytotoxic/enzymology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- Up-Regulation/immunology
- cdc42 GTP-Binding Protein/physiology
- rho-Associated Kinases
- rhoA GTP-Binding Protein/metabolism
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Affiliation(s)
- Bin Wei
- Molecular Immunology Section, Department of Immunology, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
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16
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Nguyen TV, Ke Y, Zhang EE, Feng GS. Conditional deletion of Shp2 tyrosine phosphatase in thymocytes suppresses both pre-TCR and TCR signals. THE JOURNAL OF IMMUNOLOGY 2006; 177:5990-6. [PMID: 17056523 DOI: 10.4049/jimmunol.177.9.5990] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is well known that T cell differentiation and maturation in the thymus is tightly controlled at multiple checkpoints. However, the molecular mechanism for the control of this developmental program is not fully understood. A number of protein tyrosine kinases, such as Zap-70, Lck, and Fyn, have been shown to promote signals required for thymocyte development, whereas a tyrosine phosphatase Src homology domain-containing tyrosine phosphatase (Shp)1 has a negative effect in pre-TCR and TCR signaling. We show in this study that Shp2, a close relative of Shp1, plays a positive role in T cell development and functions. Lck-Cre-mediated deletion of Shp2 in the thymus resulted in a significant block in thymocyte differentiation/proliferation instructed by the pre-TCR at the beta selection step, and reduced expansion of CD4(+) T cells. Furthermore, mature Shp2(-/-) T cells showed decreased TCR signaling in vitro. Mechanistically, Shp2 acts to promote TCR signaling through the ERK pathway, with impaired activation of ERK kinase observed in Shp2(-/-) T cells. Thus, our results provide physiological evidence that Shp2 is a common signal transducer for pre-TCR and TCR in promoting T cell maturation and proliferation.
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Affiliation(s)
- Thanh V Nguyen
- Programs in Signal Transduction and Stem Cells and Regeneration, Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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17
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Añel JA, Gimeno L, de la Torre L, Nieto R. Changes in tropopause height for the Eurasian region determined from CARDS radiosonde data. Naturwissenschaften 2006; 93:603-9. [PMID: 17047909 DOI: 10.1007/s00114-006-0147-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 06/22/2006] [Accepted: 06/25/2006] [Indexed: 10/24/2022]
Abstract
Previous studies have identified the tropopause height (TH) as a promising fingerprint of climatic change. In the present paper, we report variations in TH for the Eurasian region over the period 1973-1998 and analyse the influence of the Northern Annular Mode (NAM) on these variations. As previous studies indicate that the greatest increases in TH occur in the extratropics, we focused our attention on this area. We applied a set of homogenization procedures to radiosonde data and considered three different scenarios that take into account change points and the main volcanic eruptions over the study period. Our results demonstrate that the number of stations with positive TH trends is very sensitive to the quality of data and the methods used to remove inhomogeneities. Consequently, when change points were included in the analysis, the number of stations with positive trends decreased markedly. Furthermore, stratospheric NAM appears to control TH in stations located at latitudes higher than 55 degrees N.
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Affiliation(s)
- Juan A Añel
- Facultad de Ciencias de Ourense, Universidad de Vigo, Ourense, Spain.
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18
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Choi H, Cho SY, Schwartz RH, Choi K. Dual effects of Sprouty1 on TCR signaling depending on the differentiation state of the T cell. THE JOURNAL OF IMMUNOLOGY 2006; 176:6034-45. [PMID: 16670312 DOI: 10.4049/jimmunol.176.10.6034] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sprouty (Spry) is known to be a negative feedback inhibitor of growth factor receptor signaling through inhibition of the Ras/MAPK pathway. Several groups, however, have reported a positive role for Spry involving sequestration of the inhibitory protein c-Cbl. Thus, Spry may have various functions in the regulation of receptor-mediated signaling depending on the context. In the immune system, the function of Spry is unknown. In this study, we investigated the role of Spry1 in T cell activation. Spry1, among the four mammalian homologs, was specifically induced by TCR signaling of CD4(+) murine T cells. In fully differentiated Th1 clones, overexpressed Spry1 inhibited TCR signaling and decreased IL-2 production while reducing expression with specific siRNA transfection had the opposite effect, increasing IL-2 production. In contrast, in naive T cells, Spry1 overexpression enhanced TCR signaling, and increased proliferation and IL-2 production, while siRNA transfection again had the opposite effect, reducing IL-2 production following activation. The enhancing effect in naive cells was abrogated by preactivation of the T cells with Ag and APC, indicating that the history of exposure to Ag is correlated with a hierarchy of T cell responsiveness to Spry1. Furthermore, both the NF-AT and MAPK pathways were influenced by Spry1, implying a different molecular mechanism from that for growth factor receptor signaling. Thus, Spry1 uses a novel mechanism to bring about differential effects on TCR signaling through the same receptor, depending on the differentiation state of the T cell.
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Affiliation(s)
- Heonsik Choi
- Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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19
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Chemnitz JM, Lanfranco AR, Braunstein I, Riley JL. B and T Lymphocyte Attenuator-Mediated Signal Transduction Provides a Potent Inhibitory Signal to Primary Human CD4 T Cells That Can Be Initiated by Multiple Phosphotyrosine Motifs. THE JOURNAL OF IMMUNOLOGY 2006; 176:6603-14. [PMID: 16709818 DOI: 10.4049/jimmunol.176.11.6603] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The B and T lymphocyte attenuator (BTLA) is a recently identified member of the CD28 family of cell receptors. Initial reports demonstrated that mice deficient in BTLA expression were more susceptible to experimental autoimmune encephalomyelitis, indicating that BTLA was likely to function as a negative regulator of T cell activation. However, cross-linking of BTLA only resulted in a 2-fold reduction of IL-2 production, questioning the potency with which BTLA engagement blocks T cell activation. We established a model in which BTLA signaling could be studied in primary human CD4 T cells. We observed that cross-linking of a chimeric receptor consisting of the murine CD28 extracellular domain and human BTLA cytoplasmic tail potently inhibits IL-2 production and completely suppresses T cell expansion. Mutation of any BTLA tyrosine motifs had no effect on the ability of BTLA to block T cell activation. Only mutation of all four tyrosines rendered the BTLA cytoplasmic tail nonfunctional. We performed structure-function studies to determine which factors recruited to the BTLA cytoplasmic tail correlated with BTLA function. Using pervanadate as a means to phosphorylate the BTLA cytoplasmic tail, we observed both Src homology protein (SHP)-1 and SHP-2 recruitment. However, upon receptor engagement, we observed only SHP-1 recruitment, and mutations that abrogated SHP-1 recruitment did not impair BTLA function. These studies question whether SHP-1 or SHP-2 have any role in BTLA function and caution against the use of pervanadate as means to initiate signal transduction cascades in primary cells.
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Affiliation(s)
- Jens M Chemnitz
- Abramson Family Cancer Research Institute and Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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20
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Tseng SY, Liu M, Dustin ML. CD80 cytoplasmic domain controls localization of CD28, CTLA-4, and protein kinase Ctheta in the immunological synapse. THE JOURNAL OF IMMUNOLOGY 2006; 175:7829-36. [PMID: 16339518 PMCID: PMC1626532 DOI: 10.4049/jimmunol.175.12.7829] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The binding of costimulatory ligand CD80 to CD28 or CTLA-4 on T cells plays an important role in the regulation of the T cell response. We have examined the role of the cytoplasmic domain of CD80 in murine T cell costimulation and its organization in the immunological synapse (IS). Removal of CD80 cytoplasmic tail decreased its effectiveness in costimulating T cell proliferative response and early IL-2 production in response to agonist MHC-peptide complexes. Immunofluorescent study showed a decreased tailless CD80 accumulation in the IS of naive T cells. The two forms of CD80 accumulated differently at the IS; the tailless CD80 was colocalized with the TCR whereas the full-length CD80 was segregated from the TCR. In addition, we showed that CD80, CD28, and protein kinase Ctheta colocalized in the presence or absence of the CD80 cytoplasmic tail. Thus, the cytoplasmic tail of CD80 regulates its spatial localization at the IS and that of its receptors and T cell signaling molecules such as protein kinase Ctheta, and thereby facilitates full T cell activation.
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Affiliation(s)
- Su-Yi Tseng
- NYU School of Medicine, Skirball Institute, 540 First Avenue, SK2-4, New York, NY 10016, USA
| | - Mengling Liu
- Division of Biostatistics, NYU Cancer Institute, 650 First Avenue, 5th floor New York, NY 10016, USA
| | - Michael L. Dustin
- NYU School of Medicine, Skirball Institute, 540 First Avenue, SK2-4, New York, NY 10016, USA
- Address correspondence to Dr. Michael L. Dustin. NYU School of Medicine, Skirball Institute, 540 First Avenue, SK2-4, New York, NY 10016, USA.
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21
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Free M. Causes of differing temperature trends in radiosonde upper air data sets. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd005481] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Free M, Seidel DJ, Angell JK, Lanzante J, Durre I, Peterson TC. Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC): A new data set of large-area anomaly time series. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005jd006169] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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23
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Santer BD, Wehner MF, Wigley TML, Sausen R, Meehl GA, Taylor KE, Ammann C, Arblaster J, Washington WM, Boyle JS, Brüggemann W. Contributions of anthropogenic and natural forcing to recent tropopause height changes. Science 2003; 301:479-83. [PMID: 12881562 DOI: 10.1126/science.1084123] [Citation(s) in RCA: 343] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Observations indicate that the height of the tropopause-the boundary between the stratosphere and troposphere-has increased by several hundred meters since 1979. Comparable increases are evident in climate model experiments. The latter show that human-induced changes in ozone and well-mixed greenhouse gases account for approximately 80% of the simulated rise in tropopause height over 1979-1999. Their primary contributions are through cooling of the stratosphere (caused by ozone) and warming of the troposphere (caused by well-mixed greenhouse gases). A model-predicted fingerprint of tropopause height changes is statistically detectable in two different observational ("reanalysis") data sets. This positive detection result allows us to attribute overall tropopause height changes to a combination of anthropogenic and natural external forcings, with the anthropogenic component predominating.
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Affiliation(s)
- B D Santer
- Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
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24
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Gillett NP, Zwiers FW, Weaver AJ, Stott PA. Detection of human influence on sea-level pressure. Nature 2003; 422:292-4. [PMID: 12646917 DOI: 10.1038/nature01487] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2002] [Accepted: 02/07/2003] [Indexed: 11/09/2022]
Abstract
Greenhouse gases and tropospheric sulphate aerosols--the main human influences on climate--have been shown to have had a detectable effect on surface air temperature, the temperature of the free troposphere and stratosphere and ocean temperature. Nevertheless, the question remains as to whether human influence is detectable in any variable other than temperature. Here we detect an influence of anthropogenic greenhouse gases and sulphate aerosols in observations of winter sea-level pressure (December to February), using combined simulations from four climate models. We find increases in sea-level pressure over the subtropical North Atlantic Ocean, southern Europe and North Africa, and decreases in the polar regions and the North Pacific Ocean, in response to human influence. Our analysis also indicates that the climate models substantially underestimate the magnitude of the sea-level pressure response. This discrepancy suggests that the upward trend in the North Atlantic Oscillation index (corresponding to strengthened westerlies in the North Atlantic region), as simulated in a number of global warming scenarios, may be too small, leading to an underestimation of the impacts of anthropogenic climate change on European climate.
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Affiliation(s)
- Nathan P Gillett
- School of Earth and Ocean Sciences, University of Victoria, PO Box 3055, Victoria, British Columbia, V8W 3P6, Canada.
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25
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Santer BD. Behavior of tropopause height and atmospheric temperature in models, reanalyses, and observations: Decadal changes. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002jd002258] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Schneider H, Mandelbrot DA, Greenwald RJ, Ng F, Lechler R, Sharpe AH, Rudd CE. Cutting edge: CTLA-4 (CD152) differentially regulates mitogen-activated protein kinases (extracellular signal-regulated kinase and c-Jun N-terminal kinase) in CD4+ T cells from receptor/ligand-deficient mice. THE JOURNAL OF IMMUNOLOGY 2002; 169:3475-9. [PMID: 12244135 DOI: 10.4049/jimmunol.169.7.3475] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although CTLA-4 (CD152) has potent inhibitory effects on T cell function, the signaling events affected by this coreceptor remain to be fully defined. Mitogen-activated protein kinases (MAPK) extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) act as crucial regulators of multiple aspects of cell function. Ab ligation studies have reported an inhibitory effect of CTLA-4 on TCR-induced ERK and JNK activation. In this study, we have re-examined the specificity of CTLA-4 inhibition of MAPKs by using natural ligand with ex vivo-purified CD4(+) T cells deficient in CD80 and CD86 (double knockout), or CTLA-4, CD80, and CD86 (triple knockout). Under these conditions, CTLA-4 ligation was found to up-regulate and sustain JNK activation, while inhibiting ERK activity. At the same time, JNK activation could not account for CTLA-4 induction of TGF-beta production. Our findings demonstrate that CTLA-4 cosignaling is more complex than previously appreciated, with an ability to differentially regulate members of the MAPK family in T cells.
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Affiliation(s)
- Helga Schneider
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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27
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Abstract
What can we say about changes in the hydrologic cycle on 50-year timescales when we cannot predict rainfall next week? Eventually, perhaps, a great deal: the overall climate response to increasing atmospheric concentrations of greenhouse gases may prove much simpler and more predictable than the chaos of short-term weather. Quantifying the diversity of possible responses is essential for any objective, probability-based climate forecast, and this task will require a new generation of climate modelling experiments, systematically exploring the range of model behaviour that is consistent with observations. It will be substantially harder to quantify the range of possible changes in the hydrologic cycle than in global-mean temperature, both because the observations are less complete and because the physical constraints are weaker.
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Affiliation(s)
- Myles R Allen
- Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
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28
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Tivol EA, Gorski J. Re-establishing peripheral tolerance in the absence of CTLA-4: complementation by wild-type T cells points to an indirect role for CTLA-4. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:1852-8. [PMID: 12165509 DOI: 10.4049/jimmunol.169.4.1852] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CTLA-4 plays an important role in the down-regulation of activated T cells and in the establishment of peripheral tolerance. It has been hypothesized that CTLA-4 on the cell surface signals directly into T cells during primary immune responses, resulting in intrinsic T cell down-regulation. It is not known, however, whether CTLA-4 directly inhibits the less intense activating signals received by autoreactive T cells in the periphery. We investigated whether CTLA-4 acts intrinsically upon self-reactive cells in vivo, or whether it inhibits autoreactive cells indirectly, in a non-cell autonomous manner. The adoptive transfer of CTLA-4-deficient splenocytes or Thy 1(+) cells into recombinase-activating gene 2-deficient mice resulted in fatal inflammation and tissue destruction similar to that seen in CTLA-4-deficient mice. When an equivalent number of splenocytes or Thy 1(+) cells from wild-type animals was transferred with the CTLA-4-deficient cells, recipient mice survived indefinitely. Since CTLA-4 was absent in the T cells responsible for the inflammatory phenotype, the down-regulation of these autoreactive cells must have been facilitated indirectly by wild-type Thy 1(+) cells. In addition, a rapid reduction in the ratio of CTLA-4-deficient to wild-type cells was observed. We propose two possible indirect mechanisms by which CTLA-4 may function in the establishment and maintenance of peripheral tolerance.
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Affiliation(s)
- Elizabeth A Tivol
- Blood Research Institute, Blood Center of Southeastern Wisconsin, Milwaukee WI 53201, USA
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29
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Free M, Angell JK. Effect of volcanoes on the vertical temperature profile in radiosonde data. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2001jd001128] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Melissa Free
- Air Resources Laboratory; National Oceanic and Atmospheric Administration; Silver Spring Maryland USA
| | - James K. Angell
- Air Resources Laboratory; National Oceanic and Atmospheric Administration; Silver Spring Maryland USA
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30
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Baroja ML, Vijayakrishnan L, Bettelli E, Darlington PJ, Chau TA, Ling V, Collins M, Carreno BM, Madrenas J, Kuchroo VK. Inhibition of CTLA-4 function by the regulatory subunit of serine/threonine phosphatase 2A. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:5070-8. [PMID: 11994459 DOI: 10.4049/jimmunol.168.10.5070] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The catalytic subunit of the serine/threonine phosphatase 2A (PP2A) can interact with the cytoplasmic tail of CTLA-4. However, the molecular basis and the biological significance of this interaction are unknown. In this study, we report that the regulatory subunit of PP2A (PP2AA) also interacts with the cytoplasmic tail of CTLA-4. Interestingly, TCR ligation induces tyrosine phosphorylation of PP2AA and its dissociation from CTLA-4 when coligated. The association between PP2AA and CTLA-4 involves a conserved three-lysine motif in the juxtamembrane portion of the cytoplasmic tail of CTLA-4. Mutations of these lysine residues prevent the binding of PP2AA and enhance the inhibition of IL-2 gene transcription by CTLA-4, indicating that PP2A represses CTLA-4 function. Our data imply that the lysine-rich motif in CTLA-4 may be used to identify small molecules that block its binding to PP2A and act as agonists for CTLA-4 function.
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MESH Headings
- Abatacept
- Amino Acid Motifs/genetics
- Animals
- Antigens, CD
- Antigens, Differentiation/genetics
- Antigens, Differentiation/metabolism
- Antigens, Differentiation/pharmacology
- Antigens, Differentiation/physiology
- CTLA-4 Antigen
- Cell Line, Transformed
- Cytoplasm/genetics
- Cytoplasm/immunology
- Cytoplasm/metabolism
- Down-Regulation/genetics
- Down-Regulation/immunology
- Humans
- Immunoconjugates
- Immunosuppressive Agents/antagonists & inhibitors
- Immunosuppressive Agents/metabolism
- Immunosuppressive Agents/pharmacology
- Jurkat Cells
- Ligands
- Lymphocyte Activation/genetics
- Lysine/genetics
- Lysine/metabolism
- Mice
- Mutagenesis, Site-Directed
- Phosphoprotein Phosphatases/metabolism
- Phosphoprotein Phosphatases/physiology
- Phosphorylation
- Protein Binding/genetics
- Protein Binding/immunology
- Protein Phosphatase 2
- Protein Structure, Tertiary/genetics
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- T-Lymphocytes/immunology
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Affiliation(s)
- Miren L Baroja
- Transplantation and Immunobiology Group, John P. Robarts Research Institute, University of Western Ontario, 100 Perth Drive, London, Ontario N6A 5K8, Canada
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31
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Banerjee A, Banks AS, Nawijn MC, Chen XP, Rothman PB. Cutting edge: Suppressor of cytokine signaling 3 inhibits activation of NFATp. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:4277-81. [PMID: 11970967 DOI: 10.4049/jimmunol.168.9.4277] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Recent studies have suggested that signaling initiated by the activation of Ag receptors and signaling activated through cytokine receptors may be regulated by a common set of inhibitory proteins. Suppressor of cytokine signaling 3 (SOCS-3), which has previously been demonstrated to inhibit cytokine signaling, is induced on TCR ligation. Overexpression of SOCS-3 can inhibit transcription driven by the IL-2 promoter in response to T cell activation. This inhibitory activity correlates with the suppression of calcineurin-dependent dephosphorylation and activation of the IL-2 promoter binding transcription factor, NFATp. Infection of primary murine T cells with a retrovirus encoding SOCS-3 blocks their IL-2 production in response to activation. Interestingly, SOCS-3 was found to coimmunoprecipitate with the catalytic subunit of calcineurin. These studies suggest that SOCS-3 may regulate T cell function as part of a negative feedback loop.
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Affiliation(s)
- Arnob Banerjee
- Integrated Program in Molecular, Cellular, and Biophysical Studies, Columbia College of Physicians and Surgeons, New York, NY 10032, USA
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32
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Guntermann C, Alexander DR. CTLA-4 suppresses proximal TCR signaling in resting human CD4(+) T cells by inhibiting ZAP-70 Tyr(319) phosphorylation: a potential role for tyrosine phosphatases. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:4420-9. [PMID: 11970985 DOI: 10.4049/jimmunol.168.9.4420] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The balance between positive and negative signals plays a key role in determining T cell function. CTL-associated Ag-4 is a surface receptor that can inhibit T cell responses induced upon stimulation of the TCR and its CD28 coreceptor. Little is known regarding the signaling mechanisms elicited by CTLA-4. In this study we analyzed CTLA-4-mediated inhibition of TCR signaling in primary resting human CD4(+) T cells displaying low, but detectable, CTLA-4 cell surface expression. CTLA-4 coligation with the TCR resulted in reduced downstream protein tyrosine phosphorylation of signaling effectors and a striking inhibition of extracellular signal-regulated kinase 1/2 activation. Analysis of proximal TCR signaling revealed that TCR zeta-chain phosphorylation and subsequent zeta-associated protein of 70 kDa (ZAP-70) tyrosine kinase recruitment were not significantly affected by CTLA-4 engagement. However, the association of p56(lck) with ZAP-70 was inhibited following CTLA-4 ligation, correlating with reduced actions of p56(lck) in the ZAP-70 immunocomplex. Moreover, CTLA-4 ligation caused the selective inhibition of CD3-mediated phosphorylation of the positive regulatory ZAP-70 Y319 site. In addition, we demonstrate protein tyrosine phosphatase activity associated with the phosphorylated CTLA-4 cytoplasmic tail. The major phosphatase activity was attributed to Src homology protein 2 domain-containing tyrosine phosphatase 1, a protein tyrosine phosphatase that has been shown to be a negative regulator of multiple signaling pathways in hemopoietic cells. Collectively, our findings suggest that CTLA-4 can act early during the immune response to regulate the threshold of T cell activation.
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Affiliation(s)
- Christine Guntermann
- Laboratory of Lymphocyte Signaling and Development, Molecular Immunology Program, The Babraham Institute, Cambridge, United Kingdom
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33
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Rudd CE, Martin M, Schneider H. CTLA-4 negative signaling via lipid rafts: A new perspective. SCIENCE'S STKE : SIGNAL TRANSDUCTION KNOWLEDGE ENVIRONMENT 2002; 2002:pe18. [PMID: 11972356 DOI: 10.1126/stke.2002.128.pe18] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Proper function of the immune system requires that activation of T cells is precisely regulated. Responses to the T cell receptor are modulated by signals from other receptors. CTLA-4 (cytotoxic T lymphocyte antigen-4, also called CD152), for example, inhibits cytokine production and proliferation of T cells. Activation of T cells is associated with the accumulation of signaling proteins in lipd rafts--microdomains of the plasma membrane enriched in cholesterol and glycosphingolipds. Rudd et al. discuss evidence that CTLA-4 might inhibit cytokine production and T cell proliferation by limiting the assembly of lipid rafts, which are critical to the formation of a functional immunological synapse between antigen-presenting cells and T cells.
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Affiliation(s)
- Christopher E Rudd
- Department of Haematology, Faculty of Medicine, Imperial College School of Science, Technology and Medicine, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK
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34
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Forest CE, Stone PH, Sokolov AP, Allen MR, Webster MD. Quantifying uncertainties in climate system properties with the use of recent climate observations. Science 2002; 295:113-7. [PMID: 11778044 DOI: 10.1126/science.1064419] [Citation(s) in RCA: 324] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We derive joint probability density distributions for three key uncertain properties of the climate system, using an optimal fingerprinting approach to compare simulations of an intermediate complexity climate model with three distinct diagnostics of recent climate observations. On the basis of the marginal probability distributions, the 5 to 95% confidence intervals are 1.4 to 7.7 kelvin for climate sensitivity and -0.30 to -0.95 watt per square meter for the net aerosol forcing. The oceanic heat uptake is not well constrained, but ocean temperature observations do help to constrain climate sensitivity. The uncertainty in the net aerosol forcing is much smaller than the uncertainty range for the indirect aerosol forcing alone given in the Intergovernmental Panel on Climate Change Third Assessment Report.
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Affiliation(s)
- Chris E Forest
- Joint Program on the Science Policy of Global Change, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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35
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Tett SFB. Estimation of natural and anthropogenic contributions to twentieth century temperature change. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2000jd000028] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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36
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Kashiwada M, Giallourakis CC, Pan PY, Rothman PB. Immunoreceptor tyrosine-based inhibitory motif of the IL-4 receptor associates with SH2-containing phosphatases and regulates IL-4-induced proliferation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:6382-7. [PMID: 11714803 DOI: 10.4049/jimmunol.167.11.6382] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunoreceptor tyrosine-based inhibitory motifs (ITIM) have been implicated in the negative modulation of immunoreceptor signaling pathways. The IL-4R alpha-chain (IL-4Ralpha) contains a putative ITIM in the carboxyl terminal. To determine the role of ITIM in the IL-4 signaling pathway, we ablated the ITIM of IL-4Ralpha by deletion and site-directed mutagenesis and stably expressed the wild-type (WT) and mutant hIL-4Ralpha in 32D/insulin receptor substrate-2 (IRS-2) cells. Strikingly, 32D/IRS-2 cells expressing mutant human (h)IL-4Ralpha were hyperproliferative in response to IL-4 compared with cells expressing WT hIL-4Ralpha. Enhanced tyrosine phosphorylation of Stat6, but not IRS-2, induced by hIL-4 was observed in cells expressing mutant Y713F. Using peptides corresponding to the ITIM of hIL-4Ralpha, we demonstrate that tyrosine-phosphorylated peptides, but not their nonphosphorylated counterparts, coprecipitate SH2-containing tyrosine phosphatase-1, SH2-containing tyrosine phosphatase-2, and SH2-containing inositol 5'-phosphatase. The in vivo association of SH2-containing inositol 5'-phosphatase with IL-4Ralpha was verified by coimmunoprecipitation with anti-IL-4Ralpha Abs. These results demonstrate a functional role for ITIM in the regulation of IL-4-induced proliferation.
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MESH Headings
- Amino Acid Motifs/genetics
- Amino Acid Sequence
- Cell Line
- Cytoplasm/enzymology
- Cytoplasm/genetics
- Cytoplasm/immunology
- Enzyme Activation/genetics
- Enzyme Activation/immunology
- Humans
- Insulin Receptor Substrate Proteins
- Interleukin-4/physiology
- Intracellular Signaling Peptides and Proteins
- Janus Kinase 1
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
- Phosphoproteins/metabolism
- Phosphoric Monoester Hydrolases/metabolism
- Phosphoric Monoester Hydrolases/physiology
- Phosphorylation
- Protein Phosphatase 1
- Protein Phosphatase 2
- Protein Tyrosine Phosphatase, Non-Receptor Type 11
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
- Protein Tyrosine Phosphatases/metabolism
- Protein-Tyrosine Kinases/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Immunologic/physiology
- Receptors, Interleukin-4/genetics
- Receptors, Interleukin-4/metabolism
- Receptors, Interleukin-4/physiology
- SH2 Domain-Containing Protein Tyrosine Phosphatases
- STAT6 Transcription Factor
- Sequence Deletion
- Signal Transduction/genetics
- Signal Transduction/immunology
- Trans-Activators/metabolism
- Tyrosine/genetics
- Tyrosine/metabolism
- src Homology Domains/immunology
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Affiliation(s)
- M Kashiwada
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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37
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Santer BD, Wigley TML, Doutriaux C, Boyle JS, Hansen JE, Jones PD, Meehl GA, Roeckner E, Sengupta S, Taylor KE. Accounting for the effects of volcanoes and ENSO in comparisons of modeled and observed temperature trends. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000jd000189] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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38
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Ferrari-Lacraz S, Zheng XX, Kim YS, Li Y, Maslinski W, Li XC, Strom TB. An antagonist IL-15/Fc protein prevents costimulation blockade-resistant rejection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:3478-85. [PMID: 11544341 PMCID: PMC3806296 DOI: 10.4049/jimmunol.167.6.3478] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IL-15 is a powerful T cell growth factor (TCGF) with particular importance for the maintenance of CD8(+) T cells. Because costimulation blockade does not result in universal tolerance, we hypothesized that "escape" from costimulation blockade might represent a CD8(+) and IL-15/IL-15R(+)-dependent process. For this analysis, we have used an IL-15 mutant/Fcgamma2a protein, a potentially cytolytic protein that is also a high-affinity receptor site specific antagonist for the IL-15Ralpha receptor protein, as a therapeutic agent. The IL-15-related fusion protein was used as monotherapy or in combination with CTLA4/Fc in murine islet allograft models. As monotherapies, CTLA4/Fc and an IL-15 mutant/Fcgamma2a were comparably effective in a semiallogeneic model system, and combined treatment with IL-15 mutant/Fcgamma2a plus CTLA4/Fc produced universal permanent engraftment. In a fully MHC-mismatched strain combination known to be refractory to costimulation blockade treatment, combined treatment with both fusion proteins proved to be highly effective; >70% of recipients were tolerized. The analysis revealed that the IL-15 mutant/Fc treatment confers partial protection from both CD4(+) and CD8(+) T cell graft infiltration. In rejections occurring despite CTLA4/Fc treatment, concomitant treatment with the IL-15 mutant/Fcgamma2a protein blocked a CD8(+) T cell-dominated rejection processes. This protection was linked to a blunted proliferative response of alloreactive T cells as well silencing of CTL-related gene expression events. Hence, we have demonstrated that targeting the IL-15/IL-15R pathway represents a new and potent strategy to prevent costimulation blockade-resistant CD8(+) T cell-driven rejection.
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MESH Headings
- Abatacept
- Animals
- Antigens, CD
- Antigens, Differentiation/genetics
- Antigens, Differentiation/therapeutic use
- CD8-Positive T-Lymphocytes/drug effects
- CD8-Positive T-Lymphocytes/immunology
- CTLA-4 Antigen
- Crosses, Genetic
- Diabetes Mellitus, Experimental/surgery
- Drug Evaluation, Preclinical
- Gene Silencing
- Graft Rejection/immunology
- Graft Rejection/prevention & control
- Graft Survival/drug effects
- Graft Survival/immunology
- H-2 Antigens/immunology
- Immune Tolerance
- Immunoconjugates
- Immunosuppressive Agents/pharmacology
- Immunosuppressive Agents/therapeutic use
- Interleukin-15/genetics
- Interleukin-15/therapeutic use
- Islets of Langerhans Transplantation/immunology
- Islets of Langerhans Transplantation/pathology
- Lymphocyte Activation/drug effects
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Knockout
- Receptors, Interleukin-15
- Receptors, Interleukin-2/drug effects
- Receptors, Interleukin-2/physiology
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/pharmacology
- Recombinant Fusion Proteins/therapeutic use
- Streptozocin
- T-Lymphocytes, Cytotoxic/drug effects
- T-Lymphocytes, Cytotoxic/immunology
- Transplantation, Homologous/immunology
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Affiliation(s)
- Sylvie Ferrari-Lacraz
- Department of Medicine, Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Xin Xiao Zheng
- Department of Medicine, Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | | | - Yongsheng Li
- Department of Medicine, Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | | | - Xian Chang Li
- Department of Medicine, Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Terry B. Strom
- Department of Medicine, Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
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39
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Tanchot C, Barber DL, Chiodetti L, Schwartz RH. Adaptive tolerance of CD4+ T cells in vivo: multiple thresholds in response to a constant level of antigen presentation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:2030-9. [PMID: 11489985 DOI: 10.4049/jimmunol.167.4.2030] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The in vivo T cell response to persistent Ag contains a hyporesponsive phase following an initial expansion and subsequent partial deletion of the responding cells. The mechanism(s) responsible for this tolerance process is poorly understood. In this study, we describe a new paired transgenic model (TCR and Ag), which within 7-14 days produces 20-40 million hyporesponsive T cells. This state is characterized by an 85-95% reduction in all cytokine production, an impairment of re-expression of CD25 and CD69, and a desensitization of the proliferative response to Ag. TCR levels were normal, and in vivo mixing experiments showed no evidence for active suppression. The hyporesponsiveness partially dissipated without proliferation when the cells were transferred into a non-Ag-bearing host. If the second host expressed Ag, the T cells initially regained responsiveness, but then slowly entered an even deeper state of tolerance characterized by an additional 7- to 10-fold lowering of cytokine production and a greater desensitization of proliferation. Surprisingly, this readaptation took place with the same level of Ag presentation, suggesting that other parameters can influence the tolerance threshold. Both the readjustment in sensitivity and the reversal without Ag convincingly demonstrate for the first time a truly adaptive tolerance process in CD4+ T cells in vivo.
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MESH Headings
- Adaptation, Physiological/genetics
- Adaptation, Physiological/immunology
- Adoptive Transfer/methods
- Animals
- Antigen Presentation/genetics
- Antigen-Presenting Cells/immunology
- CD3 Complex/biosynthesis
- CD3 Complex/genetics
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/transplantation
- Columbidae
- Cytochrome c Group/genetics
- Cytochrome c Group/immunology
- Dose-Response Relationship, Immunologic
- Immune Tolerance/genetics
- Interphase/genetics
- Interphase/immunology
- Lymphocyte Activation/genetics
- Mice
- Mice, Inbred A
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Receptors, Antigen, T-Cell, alpha-beta/genetics
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Affiliation(s)
- C Tanchot
- Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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40
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Barnett TP, Pierce DW, Schnur R. Detection of anthropogenic climate change in the world's oceans. Science 2001; 292:270-4. [PMID: 11303099 DOI: 10.1126/science.1058304] [Citation(s) in RCA: 290] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Large-scale increases in the heat content of the world's oceans have been observed to occur over the last 45 years. The horizontal and temporal character of these changes has been closely replicated by the state-of-the-art Parallel Climate Model (PCM) forced by observed and estimated anthropogenic gases. Application of optimal detection methodology shows that the model-produced signals are indistinguishable from the observations at the 0.05 confidence level. Further, the chances of either the anthropogenic or observed signals being produced by the PCM as a result of natural, internal forcing alone are less than 5%. This suggests that the observed ocean heat-content changes are consistent with those expected from anthropogenic forcing, which broadens the basis for claims that an anthropogenic signal has been detected in the global climate system. Additionally, the requirement that modeled ocean heat uptakes match observations puts a strong, new constraint on anthropogenically forced climate models. It is unknown if the current generation of climate models, other than the PCM, meet this constraint.
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Affiliation(s)
- T P Barnett
- Climate Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA.
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41
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Gajewski TF, Fallarino F, Fields PE, Rivas F, Alegre ML. Absence of CTLA-4 lowers the activation threshold of primed CD8+ TCR-transgenic T cells: lack of correlation with Src homology domain 2-containing protein tyrosine phosphatase. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:3900-7. [PMID: 11238634 DOI: 10.4049/jimmunol.166.6.3900] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To examine the role of CTLA-4 in controlling Ag-specific CD8(+) T cell activation, TCR-transgenic/CTLA-4 wild-type or -deficient mice were generated in a recombination-activating gene 2-deficient background. Naive T cells from these mice responded comparably whether or not CTLA-4 was expressed. In contrast, primed T cells responded more vigorously if they lacked CTLA-4 expression. We took advantage of the difference between naive and primed T cell responses to approach the mechanism of CTLA-4 function. Single-cell analyses demonstrated that a greater fraction of CTLA-4-deficient cells responded to a fixed dose of Ag compared with CTLA-4-expressing cells, whereas the magnitude of response per cell was comparable. A shift in the dose-response curve to APCs was also observed such that fewer APCs were required to activate CTLA-4-deficient T cells to produce intracellular IFN-gamma and to proliferate. These results suggest that CTLA-4 controls the threshold of productive TCR signaling. Biochemical analysis comparing stimulated naive and primed TCR-transgenic cells revealed no obvious differences in expression of total CTLA-4, tyrosine-phosphorylated CTLA-4, and associated Src homology domain 2-containing protein tyrosine phosphatase. Thus, the biochemical mechanism explaining the differential inhibitory effect of CTLA-4 on naive and primed CD8(+) T cells remains unclear.
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MESH Headings
- Abatacept
- Adjuvants, Immunologic/biosynthesis
- Adjuvants, Immunologic/deficiency
- Adjuvants, Immunologic/genetics
- Adjuvants, Immunologic/physiology
- Animals
- Antigens, CD
- Antigens, Differentiation/biosynthesis
- Antigens, Differentiation/genetics
- Antigens, Differentiation/physiology
- CD8-Positive T-Lymphocytes/enzymology
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- CTLA-4 Antigen
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- Immunization
- Immunoconjugates
- Immunosuppressive Agents/metabolism
- Immunosuppressive Agents/pharmacology
- Interphase/genetics
- Interphase/immunology
- Lymphocyte Activation/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Knockout
- Mice, Transgenic
- Protein Tyrosine Phosphatases/physiology
- Receptors, Antigen, T-Cell/genetics
- Transfection
- Tumor Cells, Cultured
- src Homology Domains/genetics
- src Homology Domains/immunology
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Affiliation(s)
- T F Gajewski
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA.
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42
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Pioli C, Gatta L, Ubaldi V, Doria G. Inhibition of IgG1 and IgE production by stimulation of the B cell CTLA-4 receptor. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:5530-6. [PMID: 11067906 DOI: 10.4049/jimmunol.165.10.5530] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Although a large amount of information is available on the activity of CTLA-4 in T cells, the role of this receptor in B cells has not been previously characterized. Our results show that CD40 or LPS stimulation in the presence of IL-4 induces CTLA-4 expression in purified B cells; the maximum level is reached in both membrane and intracellular compartments after 48-72 h. Engagement of the B cell CTLA-4 by immobilized mAb inhibits IgG1 and IgE production and reduces the frequency of IgG1- and IgE-expressing B cells. Cepsilon and Cgamma(1) germline mRNA expression as well as NF-kappaB and STAT6 activation, events required for isotype switching, are also inhibited by CTLA-4 engagement. Together these findings show the critical role of CTLA-4 in the control of IL-4-driven isotype switching and suggest new approaches for modulating immediate-type hypersensitivity responses.
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MESH Headings
- Abatacept
- Animals
- Antibodies, Monoclonal/pharmacology
- Antigens, CD
- Antigens, Differentiation/biosynthesis
- Antigens, Differentiation/immunology
- Antigens, Differentiation/metabolism
- Antigens, Differentiation/physiology
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- CD40 Antigens/immunology
- CTLA-4 Antigen
- Cells, Cultured
- Down-Regulation/immunology
- Immunoconjugates
- Immunoglobulin Constant Regions/biosynthesis
- Immunoglobulin Constant Regions/genetics
- Immunoglobulin E/biosynthesis
- Immunoglobulin G/biosynthesis
- Immunoglobulin M/biosynthesis
- Immunoglobulin epsilon-Chains/biosynthesis
- Immunoglobulin epsilon-Chains/genetics
- Interleukin-4/pharmacology
- Lipopolysaccharides/pharmacology
- Lymphocyte Count
- Mice
- Mice, Inbred C57BL
- NF-kappa B/antagonists & inhibitors
- NF-kappa B/metabolism
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/biosynthesis
- Receptors, IgE/antagonists & inhibitors
- Receptors, IgE/biosynthesis
- STAT6 Transcription Factor
- Signal Transduction/immunology
- Trans-Activators/antagonists & inhibitors
- Trans-Activators/metabolism
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Affiliation(s)
- C Pioli
- Section of Toxicology and Biomedicine, Ente per le Nuove Tecnologie, l'Energia et l'Ambiente C.R. Casaccia., Rome, Italy.
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43
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Affiliation(s)
- Isaac M. Held
- Geophysical Fluid Dynamics Laboratory/National Oceanic and Atmospheric Administration, Princeton, New Jersey 08542
| | - Brian J. Soden
- Geophysical Fluid Dynamics Laboratory/National Oceanic and Atmospheric Administration, Princeton, New Jersey 08542
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44
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Chen Y, Song K, Eck SL. An intra-Peyer's patch gene transfer model for studying mucosal tolerance: distinct roles of B7 and IL-12 in mucosal T cell tolerance. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:3145-53. [PMID: 10975828 DOI: 10.4049/jimmunol.165.6.3145] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Development of mucosal immunity and tolerance requires coordinated expression of a number of genes within the mucosa-associated lymphoid tissue (MALT). To study the roles of these genes in the MALT, we have established a MALT-specific gene transfer model using replication-defective adenovirus as vector. In this model, the target gene of interest is directly delivered into the Peyer's patch by intra-Peyer's patch injection of the recombinant virus. Using this gene transfer model, we investigated the roles of B7-1 and IL-12 in the development of mucosal tolerance. We found that intra-Peyer's patch injection of OVA induced Ag-specific T cell hyporesponsiveness, as manifested by decreased T cell proliferation and IL-2/IFN-gamma production upon subsequent immune challenge. Intra-Peyer's patch B7-1 gene transfer at the time of OVA administration partially reversed the inhibition of T cell proliferation and IL-2 secretion, but had no effect on IFN-gamma production. By contrast, intra-Peyer's patch IL-12 gene transfer completely restored T cell proliferation and IFN-gamma secretion and partially reversed IL-2 inhibition. Using an adoptive TCR transgenic model, we further demonstrated that B7 and IL-12 played distinct roles during the inductive phase of mucosal tolerance. B7 selectively increased T cell proliferation and IL-2 secretion without affecting IFN-gamma production, whereas IL-12 increased both IL-2 and IFN-gamma production. These results indicate that B7 alone may not be sufficient to abrogate mucosal tolerance, and that cytokines such as IL-12 may also be required. Based on these findings, we propose a new model to explain the paradoxical roles of B7 in mucosal immunity and tolerance.
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Affiliation(s)
- Y Chen
- Department of Molecular and Cellular Engineering, Institute for Human Gene Therapy, and Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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45
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Barnett TP, Hegerl G, Knutson T, Tett S. Uncertainty levels in predicted patterns of anthropogenic climate change. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/2000jd900162] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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46
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Masteller EL, Chuang E, Mullen AC, Reiner SL, Thompson CB. Structural analysis of CTLA-4 function in vivo. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:5319-27. [PMID: 10799894 DOI: 10.4049/jimmunol.164.10.5319] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CTLA-4-mediated inhibition of T cell activation may be accomplished by competition for ligands and/or by signals mediated through the intracellular domain. Studies have implicated Tyr201 in the cytoplasmic domain of CTLA-4 in regulating CTLA-4 signal transduction and intracellular trafficking. To investigate the mechanism of CTLA-4 function in vivo, transgenes encoding wild-type CTLA-4 (FL), a mutant lacking the cytoplasmic domain of CTLA-4 (DeltaCTLA-4 tail), or a CTLA-4 Tyr201 mutant (Y201V) were introduced into CTLA-4-deficient mice. CTLA-4-/- mice display an autoimmune lymphoproliferative disorder resulting in tissue destruction and early death. When either the FL or the Y201V transgene was bred into CTLA-4-/- animals, a complete rescue from lymphoproliferation and autoimmunity was observed. In contrast, CTLA-4-/- mice expressing the DeltaCTLA-4 tail transgene were long lived with no evidence of multiorgan lymphocytic infiltration, but exhibited lymphadenopathy and accumulated large numbers of activated T cells. Furthermore, these animals displayed a Th2-biased phenotype which conferred susceptibility to Leishmania infection. These results indicate that the inhibitory effect of CTLA-4 is mediated in part through the ability of the extracellular domain to compete for ligands. The cytoplasmic domain of CTLA-4, however, is required for complete inhibitory function of the receptor and for regulation of Th cell differentiation in vivo.
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MESH Headings
- Abatacept
- Amino Acid Sequence
- Animals
- Antigens, CD
- Antigens, Differentiation/biosynthesis
- Antigens, Differentiation/chemistry
- Antigens, Differentiation/genetics
- Antigens, Differentiation/physiology
- CTLA-4 Antigen
- Crosses, Genetic
- Genes, Lethal/immunology
- Genetic Predisposition to Disease
- Homeostasis/genetics
- Homeostasis/immunology
- Immunoconjugates
- Immunophenotyping
- Leishmania major/immunology
- Leishmaniasis, Cutaneous/genetics
- Leishmaniasis, Cutaneous/immunology
- Lymphatic Diseases/immunology
- Lymphocyte Activation/genetics
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Molecular Sequence Data
- Splenomegaly/immunology
- T-Lymphocytes/immunology
- T-Lymphocytes/pathology
- Th2 Cells/immunology
- Th2 Cells/metabolism
- Transgenes/immunology
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Affiliation(s)
- E L Masteller
- Gwen Knapp Center for Lupus and Immunology, University of Chicago, Chicago, IL 60637, USA.
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47
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Griffin MD, Hong DK, Holman PO, Lee KM, Whitters MJ, O'Herrin SM, Fallarino F, Collins M, Segal DM, Gajewski TF, Kranz DM, Bluestone JA. Blockade of T cell activation using a surface-linked single-chain antibody to CTLA-4 (CD152). JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:4433-42. [PMID: 10779742 DOI: 10.4049/jimmunol.164.9.4433] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
CTLA-4 (CD152) engagement can down-regulate T cell activation and promote the induction of immune tolerance. However, the strategy of attenuating T cell activation by engaging CTLA-4 has been limited by sharing of its natural ligands with the costimulatory protein CD28. In the present study, a CTLA-4-specific single-chain Ab (scFv) was developed and expressed on the cell surface to promote selective engagement of this regulatory molecule. Transfectants expressing anti-CTLA-4 scFv at their surface bound soluble CTLA-4 but not soluble CD28. Coexpression of anti-CTLA-4 scFv with anti-CD3epsilon and anti-CD28 scFvs on artificial APCs reduced the proliferation and IL-2 production by resting and preactivated bulk T cells as well as CD4+ and CD8+ T cell subsets. Importantly, expression of anti-CTLA-4 scFv on the same cell surface as the TCR ligand was essential for the inhibitory effects of CTLA-4-specific ligation. CTLA-4-mediated inhibition of tyrosine phosphorylation of components of the proximal TCR signaling apparatus was similarly dependent on coexpression of TCR and CTLA-4 ligands on the same surface. These findings support a predominant role for CTLA-4 function in the modification of the proximal TCR signal. Using T cells from DO11.10 and 2C TCR transgenic mice, negative regulatory effects of selective CTLA-4 ligation were also demonstrated during the stimulation of Ag-specific CD4+ and CD8+ T cells by MHC/peptide complexes. Together these studies demonstrate that selective ligation of CTLA-4 using a membrane-bound scFv results in attenuated T cell responses only when coengaged with the TCR during T cell/APC interaction and define an approach to harnessing the immunomodulatory potential of CTLA-4-specific ligation.
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MESH Headings
- Abatacept
- Amino Acid Sequence
- Animals
- Antibodies, Blocking/biosynthesis
- Antibodies, Blocking/genetics
- Antibodies, Blocking/metabolism
- Antibodies, Blocking/pharmacology
- Antibody Specificity/genetics
- Antigens, CD
- Antigens, Differentiation/immunology
- Antigens, Differentiation/metabolism
- CD4-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/immunology
- CTLA-4 Antigen
- Cell Line
- Cytokines/biosynthesis
- Cytokines/metabolism
- Female
- Humans
- Immunoconjugates
- Immunoglobulin Variable Region/biosynthesis
- Immunoglobulin Variable Region/immunology
- Immunoglobulin Variable Region/metabolism
- Interphase/genetics
- Interphase/immunology
- Ligands
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Major Histocompatibility Complex/genetics
- Major Histocompatibility Complex/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Transgenic
- Molecular Sequence Data
- Peptides/genetics
- Peptides/immunology
- Receptors, Antigen, B-Cell/biosynthesis
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Signal Transduction/genetics
- Signal Transduction/immunology
- T-Lymphocyte Subsets/immunology
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- M D Griffin
- The Ben May Institute for Cancer Research and Department of Pathology and Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
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48
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Kato T, Nariuchi H. Polarization of naive CD4+ T cells toward the Th1 subset by CTLA-4 costimulation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:3554-62. [PMID: 10725710 DOI: 10.4049/jimmunol.164.7.3554] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this study, we examined in vitro the role of CTLA-4 costimulation in the polarization of naive CD4+ T cells toward the Th1 subset. When CTLA-4 costimulation was blocked by the inclusion of anti-CTLA-4 Fab in cultures during priming of naive CD4+ T cells with anti-CD3 in the presence of splenic adherent cells, they were polarized toward the Th2 subset. Conversely, the engagement of CTLA-4 with immobilized anti-CTLA-4 or with CD80-P815 cells polarized naive CD4+ T cells costimulated with anti-CD3 and anti-CD28 toward the Th1 subset. The CTLA-4 costimulation during priming augmented TGF-beta1 mRNA accumulation in naive CD4+ T cells, and the inclusion of anti-TGF-beta in cultures for priming suppressed the effect of CTLA-4 costimulation on the Th1 polarization. The addition of low doses of TGF-beta1 in cultures for priming of naive CD4+ T cells enhanced the production of Th1 cytokines upon secondary stimulation, although Th2 cytokine production was not affected by the doses of TGF-beta1. The CTLA-4 costimulation was also shown to suppress IL-4 production of naive CD4+ T cells upon priming. These results indicate that the costimulation against CTLA-4 drives polarization of naive CD4+ T cells toward the Th1 subset independent of IL-12 through, at least in part, the enhancement of TGF-beta1 production, and it also hampers Th2 subset differentiation by affecting IL-4 production of naive CD4+ T cells.
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Affiliation(s)
- T Kato
- Department of Allergology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
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49
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Redemann J, Turco RP, Liou KN, Russell PB, Bergstrom RW, Schmid B, Livingston JM, Hobbs PV, Hartley WS, Ismail S, Ferrare RA, Browell EV. Retrieving the vertical structure of the effective aerosol complex index of refraction from a combination of aerosol in situ and remote sensing measurements during TARFOX. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999jd901044] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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50
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Redemann J, Turco RP, Liou KN, Hobbs PV, Hartley WS, Bergstrom RW, Browell EV, Russell PB. Case studies of the vertical structure of the direct shortwave aerosol radiative forcing during TARFOX. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999jd901042] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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