1
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Stahel PF, Weckbach S, Huber-Lang MS, Stahel VP, Barnum SR. Editorial: The impact of COVID-19 on immune system-related complications in surgical patients. Front Surg 2023; 10:1132752. [PMID: 36793320 PMCID: PMC9923122 DOI: 10.3389/fsurg.2023.1132752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 01/06/2023] [Indexed: 01/31/2023] Open
Affiliation(s)
- Philip F. Stahel
- Department of Surgery, East Carolina University, Brody School of Medicine, Greenville, NC, United States,Department of Specialty Medicine, Rocky Vista University, College of Osteopathic Medicine, Parker, CO, United States,Correspondence: Philip F. Stahel
| | | | - Markus S. Huber-Lang
- Institute for Clinical and Experimental Trauma-Immunology, University Hospital Ulm, Ulm, Germany
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2
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Hao X, Li Z, Li W, Katz J, Michalek SM, Barnum SR, Pozzo-Miller L, Saito T, Saido TC, Wang Q, Roberson ED, Zhang P. Periodontal Infection Aggravates C1q-Mediated Microglial Activation and Synapse Pruning in Alzheimer's Mice. Front Immunol 2022; 13:816640. [PMID: 35178049 PMCID: PMC8845011 DOI: 10.3389/fimmu.2022.816640] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/11/2022] [Indexed: 12/24/2022] Open
Abstract
Periodontitis is a dysbiotic infectious disease that leads to the destruction of tooth supporting tissues. There is increasing evidence that periodontitis may affect the development and severity of Alzheimer's disease (AD). However, the mechanism(s) by which periodontal infection impacts the neurodegenerative process in AD remains unclear. In the present study, using an amyloid precursor protein (APP) knock-in (App KI) AD mouse model, we showed that oral infection with Porphyromonas gingivalis (Pg), a keystone pathogen of periodontitis, worsened behavioral and cognitive impairment and accelerated amyloid beta (Aβ) accumulation in AD mice, thus unquestionably and significantly aggravating AD. We also provide new evidence that the neuroinflammatory status established by AD, is greatly complicated by periodontal infection and the consequential entry of Pg into the brain via Aβ-primed microglial activation, and that Pg-induced brain overactivation of complement C1q is critical for periodontitis-associated acceleration of AD progression by amplifying microglial activation, neuroinflammation, and tagging synapses for microglial engulfment. Our study renders support for the importance of periodontal infection in the innate immune regulation of AD and the possibility of targeting microbial etiology and periodontal treatment to ameliorate the clinical manifestation of AD and lower AD prevalence.
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Affiliation(s)
- Xiaoxiao Hao
- Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Zhaofei Li
- Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Wei Li
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jannet Katz
- Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Suzanne M. Michalek
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | | | - Lucas Pozzo-Miller
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Japan
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Takaomi C. Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Japan
| | - Qin Wang
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Erik D. Roberson
- Center for Neurodegeneration and Experimental Therapeutics, Alzheimer’s Disease Center, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ping Zhang
- Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, Birmingham, AL, United States
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3
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Abstract
The soluble membrane attack complex (sMAC, a.k.a., sC5b-9 or TCC) is generated on activation of complement and contains the complement proteins C5b, C6, C7, C8, C9 together with the regulatory proteins clusterin and/or vitronectin. sMAC is a member of the MACPF/cholesterol-dependent-cytolysin superfamily of pore-forming molecules that insert into lipid bilayers and disrupt cellular integrity and function. sMAC is a unique complement activation macromolecule as it is comprised of several different subunits. To date no complement-mediated function has been identified for sMAC. sMAC is present in blood and other body fluids under homeostatic conditions and there is abundant evidence documenting changes in sMAC levels during infection, autoimmune disease and trauma. Despite decades of scientific interest in sMAC, the mechanisms regulating its formation in healthy individuals and its biological functions in both health and disease remain poorly understood. Here, we review the structural differences between sMAC and its membrane counterpart, MAC, and examine sMAC immunobiology with respect to its presence in body fluids in health and disease. Finally, we discuss the diagnostic potential of sMAC for diagnostic and prognostic applications and potential utility as a companion diagnostic.
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Affiliation(s)
| | - Doryen Bubeck
- Department of Life Sciences, Imperial College London, London, United Kingdom
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4
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Stahel PF, Barnum SR. Complement Inhibition in Coronavirus Disease (COVID)-19: A Neglected Therapeutic Option. Front Immunol 2020; 11:1661. [PMID: 32733489 PMCID: PMC7358522 DOI: 10.3389/fimmu.2020.01661] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/22/2020] [Indexed: 01/08/2023] Open
Affiliation(s)
- Philip F Stahel
- Department of Specialty Medicine, College of Osteopathic Medicine, Rocky Vista University, Parker, CO, United States
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5
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Schein TN, Blackburn TE, Heath SL, Barnum SR. Plasma levels of soluble membrane attack complex are elevated despite viral suppression in HIV patients with poor immune reconstitution. Clin Exp Immunol 2019; 198:359-366. [PMID: 31461782 DOI: 10.1111/cei.13366] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2019] [Indexed: 12/22/2022] Open
Abstract
The complement system is now a therapeutic target for the management of serious and life-threatening conditions such as paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, glomerulonephritis and other diseases caused by complement deficiencies or genetic variants. As complement therapeutics expand into more clinical conditions, monitoring complement activation is increasingly important, as is the baseline levels of complement activation fragments in blood or other body fluid levels. Although baseline complement levels have been reported in the literature, the majority of these data were generated using non-standard assays and with variable sample handling, potentially skewing results. In this study, we examined the plasma and serum levels of the soluble membrane attack complex of complement (sMAC). sMAC is formed in the fluid phase when complement is activated through the terminal pathway. It binds the regulatory proteins vitronectin and/or clusterin and cannot insert into cell membranes, and can serve as a soluble diagnostic marker in infectious disease settings, as previously shown for intraventricular shunt infections. Here we show that in healthy adults, serum sMAC levels were significantly higher than those in plasma, that plasma sMAC levels were similar between in African Americans and Caucasians and that plasma sMAC levels increase with age. Plasma sMAC levels were significantly higher in virally suppressed people living with HIV (PLWH) compared to non-HIV infected healthy donors. More specifically, PLWH with CD4+ T cell counts below 200 had even greater sMAC levels, suggesting diagnostic value in monitoring sMAC levels in this group.
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Affiliation(s)
- T N Schein
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - T E Blackburn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - S L Heath
- Department of Medicine, Division of Infectious Disease, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - S R Barnum
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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6
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Vickers A, Donnelly JP, Moore JX, Barnum SR, Schein TN, Wang HE. Epidemiology of lumbar punctures in hospitalized patients in the United States. PLoS One 2018; 13:e0208622. [PMID: 30543645 PMCID: PMC6292631 DOI: 10.1371/journal.pone.0208622] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 11/20/2018] [Indexed: 11/18/2022] Open
Abstract
Objectives Lumbar puncture (LP) is an important technique for assessing and treating neurological symptoms. The objective of this study was to describe the characteristics of diagnostic lumbar punctures performed on hospitalized patients in the United States. Methods We analyzed data from the 2010 National Inpatient Sample (NIS) and the National Emergency Department Survey (NEDS). We included patients treated in the Emergency Department (ED) as well as those admitted to an inpatient bed through the ED. We identified patients undergoing LPs from ICD-9 procedural code 03.31 and CPT code 62270. We generated nationally weighted estimates of the total number of LPs. We also assessed patient and hospital characteristics of cases undergoing LP. Results Of an estimated 135 million hospitalizations (ED + admission, or ED only), there were an estimated 362,718 LPs (331,248–394,188), including 273,612 (251,850–295,375) among adults and 89,106 (71,870–106,342) among children (<18 years old). Of the 362,718 LPs, 136,764 (122,117–151,410) were performed in the ED without admission. The most common conditions associated with LP among children were fever of unknown origin, meningitis, seizures and other perinatal conditions. The most common conditions associated with LP among adults were headache and meningitis. Conclusions Lumbar Puncture remains an important procedure for diagnostic and therapeutic uses in United States Hospitals.
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Affiliation(s)
- Adrienne Vickers
- University of South Alabama School of Medicine, Mobile, Alabama, United States of America
| | - John P. Donnelly
- Department of Emergency Medicine, University of Alabama School of Medicine, Birmingham, Alabama, United States of America
- Department of Learning Health Sciences, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Justin Xavier Moore
- Department of Emergency Medicine, University of Alabama School of Medicine, Birmingham, Alabama, United States of America
- Department of Surgery, Washington University School of Medicine, Saint Louis, MO, United States of America
| | - Scott R. Barnum
- CNine Biosolutions, LLC., Birmingham, Alabama, United States of America
| | - Theresa N. Schein
- CNine Biosolutions, LLC., Birmingham, Alabama, United States of America
| | - Henry E. Wang
- Department of Emergency Medicine, University of Alabama School of Medicine, Birmingham, Alabama, United States of America
- Department of Emergency Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- * E-mail:
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7
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Anderson AM, Schein TN, Kalapila A, Lai L, Waldrop-Valverde D, Moore RC, Franklin D, Letendre SL, Barnum SR. Soluble membrane attack complex in the blood and cerebrospinal fluid of HIV-infected individuals, relationship to HIV RNA, and comparison with HIV negatives. J Neuroimmunol 2017; 311:35-39. [PMID: 28774464 DOI: 10.1016/j.jneuroim.2017.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/20/2017] [Accepted: 07/21/2017] [Indexed: 12/14/2022]
Abstract
The soluble membrane attack complex (sMAC) represents the terminal product of the complement cascade. We enrolled 47 HIV+ adults (12 of whom underwent a second visit at least 24weeks after starting therapy) as well as 11 HIV negative controls. At baseline, cerebrospinal fluid (CSF) sMAC was detectable in 27.7% of HIV+ individuals. CSF sMAC correlated with CSF HIV RNA levels and was more likely to be detectable in HIV+ individuals on cART compared to HIV negative controls. In HIV+ participants, there were negative association trends between sMAC and neurocognitive performance but these did not reach statistical significance.
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Affiliation(s)
- Albert M Anderson
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States.
| | - Theresa N Schein
- Department of Microbiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Aley Kalapila
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States
| | - Lillin Lai
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States
| | | | - Raeanne C Moore
- Department of Psychiatry, University of California at San Diego, La Jolla, CA, United States
| | - Donald Franklin
- Department of Psychiatry, University of California at San Diego, La Jolla, CA, United States
| | - Scott L Letendre
- Department of Psychiatry, University of California at San Diego, La Jolla, CA, United States; Department of Medicine, University of California at San Diego, La Jolla, CA, United States
| | - Scott R Barnum
- Department of Microbiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
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8
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Abstract
Complement is an integral part of the immune system and protects against infection. Complement-mediated immunopathology in many autoimmune diseases and syndromes has led to the therapeutic targeting of complement and to questions around the safety of complement inhibition. Here; I examine and clarify the risks associated with complement therapeutics.
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Affiliation(s)
- Scott R Barnum
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
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9
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Stokowska A, Atkins AL, Morán J, Pekny T, Bulmer L, Pascoe MC, Barnum SR, Wetsel RA, Nilsson JA, Dragunow M, Pekna M. Complement peptide C3a stimulates neural plasticity after experimental brain ischaemia. Brain 2016; 140:353-369. [PMID: 27956400 DOI: 10.1093/brain/aww314] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 11/12/2022] Open
Abstract
Ischaemic stroke induces endogenous repair processes that include proliferation and differentiation of neural stem cells and extensive rewiring of the remaining neural connections, yet about 50% of stroke survivors live with severe long-term disability. There is an unmet need for drug therapies to improve recovery by promoting brain plasticity in the subacute to chronic phase after ischaemic stroke. We previously showed that complement-derived peptide C3a regulates neural progenitor cell migration and differentiation in vitro and that C3a receptor signalling stimulates neurogenesis in unchallenged adult mice. To determine the role of C3a-C3a receptor signalling in ischaemia-induced neural plasticity, we subjected C3a receptor-deficient mice, GFAP-C3a transgenic mice expressing biologically active C3a in the central nervous system, and their respective wild-type controls to photothrombotic stroke. We found that C3a overexpression increased, whereas C3a receptor deficiency decreased post-stroke expression of GAP43 (P < 0.01), a marker of axonal sprouting and plasticity, in the peri-infarct cortex. To verify the translational potential of these findings, we used a pharmacological approach. Daily intranasal treatment of wild-type mice with C3a beginning 7 days after stroke induction robustly increased synaptic density (P < 0.01) and expression of GAP43 in peri-infarct cortex (P < 0.05). Importantly, the C3a treatment led to faster and more complete recovery of forepaw motor function (P < 0.05). We conclude that C3a-C3a receptor signalling stimulates post-ischaemic neural plasticity and intranasal treatment with C3a receptor agonists is an attractive approach to improve functional recovery after ischaemic brain injury.
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Affiliation(s)
- Anna Stokowska
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Alison L Atkins
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Javier Morán
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Tulen Pekny
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Linda Bulmer
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Michaela C Pascoe
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Scott R Barnum
- Department of Microbiology, University of Alabama, Birmingham, Alabama, USA
| | - Rick A Wetsel
- Research Center for Immunology and Autoimmune Diseases, Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas-Houston, Houston, Texas, USA
| | - Jonas A Nilsson
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Mike Dragunow
- Department of Pharmacology and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Marcela Pekna
- Center for Brain Repair and Rehabilitation, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden .,Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Hunter Medical Research Institute, University of Newcastle, New South Wales, Australia
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10
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Abstract
The complement system is an important part of the innate and adaptive immune systems. Originally characterized as a single serum component contributing to the killing of bacteria, we now know that there are close to sixty complement proteins, multiple activation pathways and a wide range of effector functions mediated by complement. The system plays a critical role in host defense against bacteria, viruses, fungi and other pathogens. However, inappropriate complement activation contributes to the pathophysiology of autoimmune diseases and many inflammatory syndromes. Over the last several decades, therapeutic approaches to inhibit complement activation at various steps in the pathways have met with initial success, particularly at the level of the terminal pathway. This success, combined with insight from animal model studies, has lead to an unprecedented effort by biotech and pharmaceutical companies to begin developing complement inhibitors. As a result, complement has been brought for the first time to the attention of pharmacologists, toxicologists, project managers and others in the drug development industry, as well as those in the investment world. The purpose of this primer is to provide a broad overview of complement immunobiology to help those new to complement understand the rationale behind the current therapeutic directions and the investment potential of these new therapeutics.
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Affiliation(s)
- Scott R Barnum
- Department of Microbiology, University of Alabama at Birmingham, 845 19th St. S., BBRB/744, Birmingham, AL 35294, United States; Department of Neurology, University of Alabama at Birmingham, 845 19th St. S., BBRB/744, Birmingham, AL 35294, United States.
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11
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Ramos TN, Arynchyna AA, Blackburn TE, Barnum SR, Johnston JM. Soluble membrane attack complex is diagnostic for intraventricular shunt infection in children. JCI Insight 2016; 1:e87919. [PMID: 27699221 DOI: 10.1172/jci.insight.87919] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Children treated with cerebrospinal fluid (CSF) shunts to manage hydrocephalus frequently develop shunt failure and/or infections, conditions that present with overlapping symptoms. The potential life-threatening nature of shunt infections requires rapid diagnosis; however, traditional microbiology is time consuming, expensive, and potentially unreliable. We set out to identify a biomarker that would identify shunt infection. METHODS CSF was assayed for the soluble membrane attack complex (sMAC) by ELISA in patients with suspected shunt failure or infection. CSF was obtained at the time of initial surgical intervention. Statistical analysis was performed to assess the diagnostic potential of sMAC in pyogenic-infected versus noninfected patients. RESULTS Children with pyogenic shunt infection had significantly increased sMAC levels compared with noninfected patients (3,211 ± 1,111 ng/ml vs. 26 ± 3.8 ng/ml, P = 0.0001). In infected patients undergoing serial CSF draws, sMAC levels were prognostic for both positive and negative clinical outcomes. Children with delayed, broth-only growth of commensal organisms (P. acnes, S. epidermidis, etc.) had the lowest sMAC levels (7.96 ± 1.7 ng/ml), suggesting contamination rather than shunt infection. CONCLUSION Elevated CSF sMAC levels are both sensitive and specific for diagnosing pyogenic shunt infection and may serve as a useful prognostic biomarker during recovery from infection. FUNDING This work was supported in part by the Impact Fund of Children's of Alabama.
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Affiliation(s)
| | - Anastasia A Arynchyna
- Division of Pediatric Neurosurgery, Department of Neurosurgery, Children's of Alabama
| | | | - Scott R Barnum
- Department of Microbiology.,Department of Neurology, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA
| | - James M Johnston
- Division of Pediatric Neurosurgery, Department of Neurosurgery, Children's of Alabama
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12
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Johnston JM, Ramos TN, Arynchyna AA, Blackburn TE, Amburgy J, Rocque BG, Blount JP, Rozzelle CJ, Oakes J, Barnum SR. 190 Complement Membrane Attack Complex (MAC) Level in CSF Provides Rapid Identification of Shunt Infection and Failure. Neurosurgery 2015. [DOI: 10.1227/01.neu.0000467154.21290.7f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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13
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Gong B, Levine S, Barnum SR, Pasinetti GM. Role of complement systems in IVIG mediated attenuation of cognitive deterioration in Alzheimer's disease. Curr Alzheimer Res 2015; 11:637-44. [PMID: 25115545 DOI: 10.2174/1567205011666140812113707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 06/25/2014] [Accepted: 07/13/2014] [Indexed: 11/22/2022]
Abstract
Human intravenous immunoglobulin (IVIG) has been indicated as a potential therapy for autoimmune neurological disorders, as well as in many neurodegenerative diseases, with various underlying therapeutic mechanisms such as regulation of T-cell trafficking, cytokines, Fc receptor blocking, and interruption of complement activation cascade. In Alzheimer's disease (AD), IVIG presents naturally occurring antibodies against amyloid-beta (Aβ) aggregation, thus IVIG immunotherapy may increase the clearance of Aβ and protect brain function. Recently, we and others reported that besides Aβ clearance, IVIG specifically regulates the levels of complement-derived anaphylatoxins, such as C5a and C3, which play an important role in the regulation of AMPA and NMDA receptor expression in the brain and further upregulate the AMPA-PKA-CREB signaling pathway and synaptic function in AD mouse models. Since down-regulation of complement components has been linked with deficits of cognitive function in age-related dementia following the decline of innate immunity during aging, the IVIG immunotherapy could be an attractive novel AD therapeutic through its local regulation of C3, C5a component levels in brain.
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Affiliation(s)
| | | | | | - Giulio M Pasinetti
- Mount Sinai School of Medicine, Department of Neurology, 1468 Madison Avenue, New York, NY 10029, USA.
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14
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Abstract
Activation of complement leads to generation of the 3 anaphylatoxins C3a, C4a, and C5a. Although all 3 peptides are structurally similar, only C3a and C5a share a similar functional profile that includes the classic inflammatory activities and, more recently, developmental homing and regenerative properties among others. In contrast, the functional profile of C4a is questionable in most cases owing to contamination of C4a preparations with physiologically relevant levels of C3a and/or C5a. Combined with the absence of an identified C4a receptor and the inability of C4a to signal through the C3a and C5a receptors, it is clear that C4a should not be included in the family of complement anaphylatoxins.
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Affiliation(s)
- Scott R Barnum
- Departments of Microbiology and Neurobiology, University of Alabama at Birmingham, Birmingham, Ala., USA
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15
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Buckingham SC, Ramos TN, Barnum SR. Complement C5-deficient mice are protected from seizures in experimental cerebral malaria. Epilepsia 2014; 55:e139-42. [PMID: 25385326 DOI: 10.1111/epi.12858] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2014] [Indexed: 12/01/2022]
Abstract
Studies have demonstrated that the membrane attack complex (MAC) of complement can evoke seizures when injected directly into rodent brain. In the course of studies that examine the role of complement in the development of experimental cerebral malaria (ECM), we observed fewer seizures in mice deficient in C5, a component required for MAC formation. To determine if the MAC contributed to the tonic-clonic seizures characteristic of ECM, we performed long-term video-electroencephalography (EEG) on C5(-/-) mice with Plasmodium berghei ANKA-induced cerebral malaria and observed significantly reduced spike and seizure frequency compared to wild-type mice. Our data suggest a role for the MAC in malaria-induced seizures and that inhibition of the terminal complement pathway may reduce seizures and seizure-related neurocognitive deficits.
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Affiliation(s)
- Susan C Buckingham
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama, U.S.A
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16
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Abstract
BACKGROUND C-reactive protein (CRP) level correlates with parasitemia and severity of malaria, but whether this reflects causality remains unknown. METHODS Using CRP-transgenic and CRP-deficient mice we compared the onset and severity of experimental cerebral malaria (ECM) induced by Plasmodium berghei ANKA (PbA). RESULTS CRP-deficient mice were most resistant to ECM. CONCLUSIONS CRP might contribute to the development of cerebral malaria, rather than protect against it.
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Affiliation(s)
- Alexander J Szalai
- Department of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Scott R Barnum
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Theresa N Ramos
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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17
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Abstract
ICAM-1 plays an important role in leukocyte trafficking, immunological synapse formation, and numerous cellular immune responses. Although considered a single glycoprotein, there are multiple membrane-bound and soluble ICAM-1 isoforms that arise from alternative splicing and proteolytic cleavage during inflammatory responses. The function and expression of these isoforms on various cell types are poorly understood. In the generation of ICAM-1-deficient mice, two isoform-deficient ICAM-1 mutants were inadvertently produced as a result of alternative splicing. These mice, along with true ICAM-1-deficient mice and newly generated ICAM-1-transgenic mice, have provided the opportunity to begin examining the role of ICAM-1 isoforms (singly or in combination) in various disease settings. In this review, we highlight the sharply contrasting disease phenotypes using ICAM-1 isoform mutant mice. These studies demonstrate that ICAM-1 immunobiology is highly complex but that individual isoforms, aside from the full-length molecule, make significant contributions to disease development and pathogenesis.
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Affiliation(s)
- Theresa N Ramos
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
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18
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Hu X, Patel RP, Weinberg JA, Marques MB, Ramos TN, Barnum SR. Membrane attack complex generation increases as a function of time in stored blood. Transfus Med 2014; 24:114-6. [PMID: 24588971 DOI: 10.1111/tme.12109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 11/13/2013] [Accepted: 02/02/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine if the complement system, a potent mediator of inflammation, contributes to haemolysis during red blood cell (RBC) storage. BACKGROUND RBCs in storage undergo structural and biochemical changes that may result in adverse patient outcomes post-transfusion. Complement activation on leukodepletion and during storage may contribute to the RBC storage lesion. METHODS/MATERIALS We performed a cross-sectional analysis of aliquots of leukoreduced RBC units, stored for 1-6 weeks, for the levels of C3a, C5a, Bb, iC3b, C4d and C5b-9 [membrane attack complex (MAC)] by enzyme-linked immunosorbent assay (ELISA). RESULTS We observed that only MAC levels significantly increased in RBC units as a function of storage time. We also observed that the level of C5b-9 bound to RBCs increased as a function of storage time. CONCLUSION MAC levels increased over time, suggesting that MAC is the primary complement-mediated contributor to changes in stored RBCs. Inhibition of the terminal complement pathway may stabilise RBC functionality and extend shelf life.
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Affiliation(s)
- X Hu
- Department of Microbiology
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Bullard DC, Hu X, Crawford D, McDonald K, Ramos TN, Barnum SR. Expression of a single ICAM-1 isoform on T cells is sufficient for development of experimental autoimmune encephalomyelitis. Eur J Immunol 2014; 44:1194-9. [PMID: 24435747 DOI: 10.1002/eji.201344023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 12/02/2013] [Accepted: 01/13/2014] [Indexed: 01/30/2023]
Abstract
Intercellular adhesion molecule-1 (ICAM-1) plays an important role in leukocyte trafficking, induction of cellular immune responses, and immunological synapse formation. As a member of the immunoglobulin superfamily of adhesion proteins, ICAM-1 is composed of repeating Ig-like domains, a transmembrane domain, and short cytoplasmic tail that participates in intracellular signaling events. At least seven ICAM-1 protein isoforms are generated by alternative splicing, however little is known regarding their immunobiology. We have previously shown using different lines of ICAM-1 mutant mice (Icam1(tm1Jcgr) and Icam1(tm1Bay) ) that expression of alternatively spliced ICAM-1 isoforms can significantly influence the disease course during the development of EAE. In this study, we show using a newly developed transgenic mouse (CD2-Icam1(D4del) /Icam1(null) ) that T-cell-specific expression of a single ICAM-1 isoform composed of Ig domains 1, 2, 3, and 5 can mediate the initiation and progression of EAE. Our results indicate that the ICAM-1 isoform lacking Ig domain 4 can drive pathogenesis in demyelinating disease and may be a novel therapeutic target for treating multiple sclerosis.
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Affiliation(s)
- Daniel C Bullard
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
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Hu X, Barnum SR, Patel RP, Marques MB, Weinberg JA. The level of complement activation fragments is higher in red blood cell units than segments. Transfus Apher Sci 2013; 49:692-3. [PMID: 24189461 DOI: 10.1016/j.transci.2013.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/09/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Xianzhen Hu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
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Read RW, Vogt SD, Barnum SR. The complement anaphylatoxin receptors are not required for the development of experimental autoimmune uveitis. J Neuroimmunol 2013; 264:127-9. [PMID: 24035596 DOI: 10.1016/j.jneuroim.2013.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/19/2013] [Accepted: 08/21/2013] [Indexed: 02/06/2023]
Abstract
To determine if complement anaphylatoxin-mediated inflammation contributes to the development and progression of experimental autoimmune uveitis (EAU), we induced disease in wild type and complement anaphylatoxin receptor-deficient mice (C3a receptor(-/-), C5a receptor(-/-) and C3aR(-/-)/C5aR(-/-)) and evaluated the eyes three weeks post-induction. No differences in disease severity or in disease incidence were seen between wild type controls and anaphylatoxin receptor-deficient mice. Our data indicate that C3a and C5a-mediated functions are not critical to the development of EAU.
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Affiliation(s)
- Russell W Read
- Department of Ophthalmology, The University of Alabama at Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294-1150, USA; Department of Pathology, The University of Alabama at Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294-1150, USA; Department of Microbiology, The University of Alabama at Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294-1150, USA.
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Hu X, Wetsel RA, Ramos TN, Mueller-Ortiz SL, Schoeb TR, Barnum SR. Carboxypeptidase N-deficient mice present with polymorphic disease phenotypes on induction of experimental autoimmune encephalomyelitis. Immunobiology 2013; 219:104-8. [PMID: 24028840 DOI: 10.1016/j.imbio.2013.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/08/2013] [Accepted: 08/16/2013] [Indexed: 10/26/2022]
Abstract
Carboxypeptidase N (CPN) is a member of the carboxypeptidase family of enzymes that cleave carboxy-terminal lysine and arginine residues from a large number of biologically active peptides and proteins. These enzymes are best known for their roles in modulating the activity of kinins, complement anaphylatoxins and coagulation proteins. Although CPN makes important contributions to acute inflammatory events, little is known about its role in autoimmune disease. In this study we used CPN(-/-) mice in experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. Unexpectedly, we observed several EAE disease phenotypes in CPN(-/-) mice compared to wild type mice. The majority of CPN(-/-) mice died within five to seven days after disease induction, before displaying clinical signs of disease. The remaining mice presented with either mild EAE or did not develop EAE. In addition, CPN(-/-) mice injected with complete or incomplete Freund's adjuvant died within the same time frame and in similar numbers as those induced for EAE. Overall, the course of EAE in CPN(-/-) mice was significantly delayed and attenuated compared to wild type mice. Spinal cord histopathology in CPN(-/-) mice revealed meningeal, but not parenchymal leukocyte infiltration, and minimal demyelination. Our results indicate that CPN plays an important role in EAE development and progression and suggests that multiple CPN ligands contribute to the disease phenotypes we observed.
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Affiliation(s)
- Xianzhen Hu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Rick A Wetsel
- Brown Foundation Institute of Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Theresa N Ramos
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Stacey L Mueller-Ortiz
- Brown Foundation Institute of Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Trenton R Schoeb
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Scott R Barnum
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Järlestedt K, Rousset CI, Ståhlberg A, Sourkova H, Atkins AL, Thornton C, Barnum SR, Wetsel RA, Dragunow M, Pekny M, Mallard C, Hagberg H, Pekna M. Receptor for complement peptide C3a: a therapeutic target for neonatal hypoxic‐ischemic brain injury. FASEB J 2013; 27:3797-804. [DOI: 10.1096/fj.13-230011] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | | | - Anders Ståhlberg
- Center for Brain Repair and RehabilitationDepartment of Clinical Neuroscience and RehabilitationInstitute of Neuroscience and PhysiologySahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Hana Sourkova
- Center for Brain Repair and RehabilitationDepartment of Clinical Neuroscience and RehabilitationInstitute of Neuroscience and PhysiologySahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Alison L. Atkins
- Center for Brain Repair and RehabilitationDepartment of Clinical Neuroscience and RehabilitationInstitute of Neuroscience and PhysiologySahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | | | - Scott R. Barnum
- Department of MicrobiologyUniversity of AlabamaBirminghamAlabamaUSA
| | - Rick A. Wetsel
- Research Center for Immunology and Autoimmune DiseasesInstitute of Molecular Medicine for the Prevention of Human DiseasesUniversity of Texas‐HoustonHoustonTexasUSA
| | - Mike Dragunow
- Department of PharmacologyFaculty of Medical and Health SciencesThe University of AucklandAucklandNew Zealand
- The National Research Centre for Growth and DevelopmentFaculty of Medical and Health SciencesThe University of AucklandAucklandNew Zealand
| | - Milos Pekny
- Center for Brain Repair and RehabilitationDepartment of Clinical Neuroscience and RehabilitationInstitute of Neuroscience and PhysiologySahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Carina Mallard
- Perinatal CenterSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Henrik Hagberg
- Perinatal CenterSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Department of Obstetrics and GynecologySahlgrenska AcademyUniversity of GothenburgGothenburgSweden
- Centre for the Developing BrainKing's CollegeLondonUK
| | - Marcela Pekna
- Center for Brain Repair and RehabilitationDepartment of Clinical Neuroscience and RehabilitationInstitute of Neuroscience and PhysiologySahlgrenska AcademyUniversity of GothenburgGothenburgSweden
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Ramos TN, Bullard DC, Darley MM, McDonald K, Crawford DF, Barnum SR. Experimental cerebral malaria develops independently of endothelial expression of intercellular adhesion molecule-1 (icam-1). J Biol Chem 2013; 288:10962-6. [PMID: 23493396 DOI: 10.1074/jbc.c113.457028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cerebral malaria (CM) is a severe clinical complication of Plasmodium falciparum malaria infection and is characterized by a high fatality rate and neurological damage. Sequestration of parasite-infected red blood cells in brain microvasculature utilizes host- and parasite-derived adhesion molecules and is an important factor in the development of CM. ICAM-1, an alternatively spliced adhesion molecule, is believed to be critical on endothelial cells for infected red blood cell sequestration in CM. Using ICAM-1 mutant mice, we found that the full-length ICAM-1 isoform is not required for development of murine experimental CM (ECM) and that ECM phenotype varies with the combination of ICAM-1 isoforms expressed. Furthermore, we observed development of ECM in transgenic mice expressing ICAM-1 only on leukocytes, indicating that endothelial cell expression of this adhesion molecule is not required for disease pathogenesis. We propose that ICAM-1-dependent cellular aggregation, independent of ICAM-1 expression on the cerebral microvasculature, contributes to ECM.
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Affiliation(s)
- Theresa N Ramos
- Department of Microbiology and Neurology, University of Alabama, Birmingham, Alabama 35294, USA
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Ramos TN, Bullard DC, Barnum SR. Deletion of the complement phagocytic receptors CR3 and CR4 does not alter susceptibility to experimental cerebral malaria. Parasite Immunol 2013; 34:547-50. [PMID: 22882618 DOI: 10.1111/pim.12002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Complement receptors for C3-derived fragments (CR1-4) play critical roles in innate and adaptive immune responses. Of these receptors, CR3 and CR4 are important in binding and phagocytosis of complement-opsonized pathogens including parasites. The role of CR3 and CR4 in malaria or in cerebral malaria (CM) has received little attention and remains poorly understood in both human disease and rodent models of malaria. CR3 and CR4 are members of the β(2) -integrin family of adhesion molecules and are expressed on all leucocytes that participate in the development of CM, most importantly as it relates to parasite phagocytosis (monocytes/macrophages) and antigen processing and presentation (dendritic cells). Thus, it is possible that these receptors might play an important role in disease development. To address this question, we examined the role of CR3(-/-) and CR4(-/-) in experimental cerebral malaria (ECM). We found that both CR3(-/-) and CR4(-/-) mice were fully susceptible to ECM and developed disease comparable to wild-type mice. Our results indicate that CR3 and CR4 are not critical to the pathogenesis of ECM despite their role in elimination of complement-opsonized pathogens. These findings support recent studies indicating the importance of the terminal complement pathway and the membrane attack complex in ECM pathogenesis.
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Affiliation(s)
- T N Ramos
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Hu X, Holers VM, Thurman JM, Schoeb TR, Ramos TN, Barnum SR. Therapeutic inhibition of the alternative complement pathway attenuates chronic EAE. Mol Immunol 2013; 54:302-8. [PMID: 23337717 DOI: 10.1016/j.molimm.2012.12.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 12/14/2012] [Indexed: 12/13/2022]
Abstract
Previous studies from our laboratory using complement-mutant mice demonstrated that the alternative pathway is the dominant activation pathway responsible for complement-mediated pathology in demyelinating disease. Using a well-characterized inhibitory monoclonal antibody (mAb 1379) directed against mouse factor B, we assessed the therapeutic value of inhibiting the alternative complement pathway in experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. Administration of anti-factor B antibody to mice prior to the onset of clinical signs of active EAE had no affect on the onset or acute phase of disease, but significantly attenuated the chronic phase of disease resulting in reduced cellular infiltration, inflammation and demyelination in antibody-treated mice. Attenuation of the chronic phase of disease was long lasting even though antibody administration was terminated shortly after disease onset. Chronic disease was also attenuated in transferred EAE when anti-factor B antibody was administered before or after disease onset. Similar levels of disease attenuation were observed in transferred EAE using MOG-specific encephalitogenic T cells. These studies demonstrate the therapeutic potential for inhibition of factor B in the chronic phase of demyelinating disease, where treatment options are limited.
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Affiliation(s)
- Xianzhen Hu
- Department of Microbiology, University of Alabama at Birmingham, 845 19th St. S., Birmingham, AL 35294, USA
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Abstract
Complement contributes to inflammation during pathogen infections; however, less is known regarding its role during malaria and in the severest form of the disease, cerebral malaria. Recent studies have shown that deletion of the complement anaphylatoxins receptors, C3aR and C5aR, does not alter disease susceptibility in experimental cerebral malaria (ECM). This does not, however, preclude C3a- and C5a-mediated contributions to inflammation in ECM and raises the possibility that carboxypeptidase regulation of anaphylatoxin activity rapidly over rides their functions. To address this question, we performed ECM using carboxypeptidase N-deficient (CPN(-/-)) mice. Unexpectedly, we found that CPN(-/-) mice survived longer than wild-type mice, but they were fully susceptible to ECM. CD4(+) and CD8(+) T cell infiltration was not reduced at the peak of disease in CPN(-/-) mice, and there was no corresponding reduction in pro-inflammatory cytokine production. Our results indicate that carboxypeptidases contribute to the pathogenesis of ECM and that studies examining the contribution of other carboxypeptidase families and family members may provide greater insight into the role these enzymes play in malaria.
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Affiliation(s)
- M M Darley
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Hu X, Tomlinson S, Barnum SR. Targeted inhibition of complement using complement receptor 2-conjugated inhibitors attenuates EAE. Neurosci Lett 2012; 531:35-9. [PMID: 23079547 DOI: 10.1016/j.neulet.2012.10.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 10/04/2012] [Accepted: 10/07/2012] [Indexed: 01/27/2023]
Abstract
Multiple sclerosis (MS) is the most common autoimmune demyelinating disease, affecting millions of individuals worldwide. In the last two decades, many therapeutic options for the treatment of MS have become available, however they are limited in terms of effectiveness and some remain plagued by safety issues. The currently available treatment options target relapsing remitting forms of MS and are not effective against the more progressive forms of the disease. These limitations highlight a significant unmet treatment need for MS. In experimental autoimmune encephalomyelitis (EAE) studies from our laboratory, we have previously shown, using a number of complement mutant and transgenic mice, that inhibition of the alternative complement pathway and the C3 convertase confers significant protection from disease. We report here that targeted inhibition of complement activation using complement receptor 2 (CR2)-conjugated inhibitors significantly attenuates EAE. Administration of CR2-Crry (blocks all complement pathways at C3 activation) and CR2-fH (specifically blocks the alternative pathway) just prior to and during the onset of EAE blocks progression of both acute and chronic disease. These data indicate that inhibition of complement may offer an effective therapeutic approach to treating both acute and chronic forms of demyelinating disease through blocking the alternative pathway or complement convertases.
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Affiliation(s)
- Xianzhen Hu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Ramos TN, Darley MM, Weckbach S, Stahel PF, Tomlinson S, Barnum SR. The C5 convertase is not required for activation of the terminal complement pathway in murine experimental cerebral malaria. J Biol Chem 2012; 287:24734-8. [PMID: 22689574 DOI: 10.1074/jbc.c112.378364] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cerebral malaria (CM) is the most severe manifestation of clinical malaria syndromes and has a high fatality rate especially in the developing world. Recent studies demonstrated that C5(-/-) mice are resistant to experimental CM (ECM) and that protection was due to the inability to form the membrane attack complex. Unexpectedly, we observed that C4(-/-) and factor B(-/-) mice were fully susceptible to disease, indicating that activation of the classical or alternative pathways is not required for ECM. C3(-/-) mice were also susceptible to ECM, indicating that the canonical C5 convertases are not required for ECM development and progression. Abrogation of ECM by treatment with anti-C9 antibody and detection of C5a in serum of C3(-/-) mice confirmed that C5 activation occurs in ECM independent of C5 convertases. Our data indicate that activation of C5 in ECM likely occurs via coagulation enzymes of the extrinsic protease pathway.
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Affiliation(s)
- Theresa N Ramos
- Department of Microbiology, University of Alabama, Birmingham, Alabama 35294, USA
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Woehrl B, Brouwer MC, Murr C, Heckenberg SGB, Baas F, Pfister HW, Zwinderman AH, Morgan BP, Barnum SR, van der Ende A, Koedel U, van de Beek D. Complement component 5 contributes to poor disease outcome in humans and mice with pneumococcal meningitis. J Clin Invest 2011; 121:3943-53. [PMID: 21926466 DOI: 10.1172/jci57522] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 08/03/2011] [Indexed: 01/05/2023] Open
Abstract
Pneumococcal meningitis is the most common and severe form of bacterial meningitis. Fatality rates are substantial, and long-term sequelae develop in about half of survivors. Disease outcome has been related to the severity of the proinflammatory response in the subarachnoid space. The complement system, which mediates key inflammatory processes, has been implicated as a modulator of pneumococcal meningitis disease severity in animal studies. Additionally, SNPs in genes encoding complement pathway proteins have been linked to susceptibility to pneumococcal infection, although no associations with disease severity or outcome have been established. Here, we have performed a robust prospective nationwide genetic association study in patients with bacterial meningitis and found that a common nonsynonymous complement component 5 (C5) SNP (rs17611) is associated with unfavorable disease outcome. C5 fragment levels in cerebrospinal fluid (CSF) of patients with bacterial meningitis correlated with several clinical indicators of poor prognosis. Consistent with these human data, C5a receptor-deficient mice with pneumococcal meningitis had lower CSF wbc counts and decreased brain damage compared with WT mice. Adjuvant treatment with C5-specific monoclonal antibodies prevented death in all mice with pneumococcal meningitis. Thus, our results suggest C5-specific monoclonal antibodies could be a promising new antiinflammatory adjuvant therapy for pneumococcal meningitis.
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Affiliation(s)
- Bianca Woehrl
- Department of Neurology, Klinikum Grosshadern, Ludwig Maximilians University, Munich, Germany
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Abstract
The specific negative clinical manifestations associated with the transfusion of stored red blood cells (RBCs) and the corresponding mechanisms responsible for such phenomena remain poorly defined. Our recent studies document that leukoreduced older RBC units potentiate transfusion-related toxicity in trauma patients. It is our hypothesis that the transfusion of relatively older blood impedes microvascular perfusion. The central mechanisms proposed to mediate this microcirculatory alteration include: 1) the loss of RBC-dependent control of nitric oxide-mediated homeostasis concerning vasodilation and 2) immune cell and complement activation. In this review, we outline the background for our hypothesis and detail our current investigations toward the understanding of this pathophysiology.
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Affiliation(s)
- Jordan A Weinberg
- Department of Surgery, University of Tennessee Health Science Center, 910 Madison Avenue, #224, Memphis, TN 38103, USA.
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Ramos TN, Darley MM, Hu X, Billker O, Rayner JC, Ahras M, Wohler JE, Barnum SR. Cutting edge: the membrane attack complex of complement is required for the development of murine experimental cerebral malaria. J Immunol 2011; 186:6657-60. [PMID: 21572031 DOI: 10.4049/jimmunol.1100603] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cerebral malaria is the most severe complication of Plasmodium falciparum infection and accounts for a large number of malaria fatalities worldwide. Recent studies demonstrated that C5(-/-) mice are resistant to experimental cerebral malaria (ECM) and suggested that protection was due to loss of C5a-induced inflammation. Surprisingly, we observed that C5aR(-/-) mice were fully susceptible to disease, indicating that C5a is not required for ECM. C3aR(-/-) and C3aR(-/-) × C5aR(-/-) mice were equally susceptible to ECM as were wild-type mice, indicating that neither complement anaphylatoxin receptor is critical for ECM development. In contrast, C9 deposition in the brains of mice with ECM suggested an important role for the terminal complement pathway. Treatment with anti-C9 Ab significantly increased survival time and reduced mortality in ECM. Our data indicate that protection from ECM in C5(-/-) mice is mediated through inhibition of membrane attack complex formation and not through C5a-induced inflammation.
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Affiliation(s)
- Theresa N Ramos
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Hu XZ, Wright TT, Jones NR, Ramos TN, Skibinski GA, McCrory MA, Barnum SR, Szalai AJ. Inhibition of Experimental Autoimmune Encephalomyelitis in Human C-Reactive Protein Transgenic Mice Is FcγRIIB Dependent. Autoimmune Dis 2010; 2011:484936. [PMID: 21151582 PMCID: PMC2989644 DOI: 10.4061/2011/484936] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 09/24/2010] [Indexed: 12/02/2022] Open
Abstract
We showed earlier that experimental autoimmune encephalomyelitis (EAE) in human C-reactive protein (CRP) transgenic mice (CRPtg) has delayed onset and reduced severity compared to wild-type mice. Since human CRP is known to engage Fc receptors and Fc receptors are known to play a role in EAE in the mouse, we sought to determine if FcγRI, FcγRIIb, or FcγRIII was needed to manifest human CRP-mediated protection of CRPtg. We report here that in CRPtg lacking either of the two activating receptors, FcγRI and FcγRIII, the beneficial effects of human CRP are still observed. In contrast, if CRPtg lack expression of the inhibitory receptor FcγRIIB, then the beneficial effect of human CRP is abrogated. Also, subcutaneous administration of purified human CRP stalled progression of ongoing EAE in wild-type mice, but similar treatment failed to impede EAE progression in mice lacking FcγRIIB. The results reveal that a CRP → FcγRIIB axis is responsible for protection against EAE in the CRPtg model.
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Affiliation(s)
- Xian-Zhen Hu
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, 1825 University Boulevard, SHEL 214, Birmingham, AL 35294-2182, USA
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Hunt NH, Grau GE, Engwerda C, Barnum SR, van der Heyde H, Hansen DS, Schofield L, Golenser J. Murine cerebral malaria: the whole story. Trends Parasitol 2010; 26:272-4. [DOI: 10.1016/j.pt.2010.03.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 03/08/2010] [Accepted: 03/09/2010] [Indexed: 01/10/2023]
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Hu X, Barnum SR, Wohler JE, Schoeb TR, Bullard DC. Differential ICAM-1 isoform expression regulates the development and progression of experimental autoimmune encephalomyelitis. Mol Immunol 2010; 47:1692-1700. [PMID: 20371120 DOI: 10.1016/j.molimm.2010.03.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 02/25/2010] [Accepted: 03/07/2010] [Indexed: 10/19/2022]
Abstract
Intercellular adhesion molecule-1 (ICAM-1) functions in leukocyte trafficking, activation, and the formation of the immunological synapse. ICAM-1 is a member of the immunoglobulin superfamily of adhesion proteins, which share a similar structure of repeating Ig-like domains. Many genes in this family, including ICAM-1, show alternative splicing leading to the production of different protein isoforms, although little functional information is available regarding the expression patterns, ligand interactions, and functions of these isoforms, especially those arising from the ICAM-1 gene. In this study, we show using different lines of mutant mice (Icam1(tm1Jcgr) and Icam1(tm1Bay)) that alterations in the expression of the alternatively spliced ICAM-1 isoforms can significantly influence the disease course during the development of EAE. Icam1(tm1Jcgr) mutant mice, unlike Icam1(tm1Bay) mutants, do not express isoforms containing the Mac-1 binding domain and had significantly attenuated of EAE. In contrast, Icam1(tm1Bay) mice developed severe EAE in both active and adoptive transfer models compared to both Icam1(tm1Jcgr) and wild type mice. We also observed that T cells from Icam1(tm1Bay) mice displayed increased proliferation kinetics and produced higher levels of IFN-gamma compared to Icam1(tm1Jcgr) and wild type mice. Thus, our investigations show that the alternatively spliced ICAM-1 isoforms are functional, and play key roles during the progression of CNS inflammation and demyelination in EAE. Furthermore, our findings suggest that these isoforms may also play key roles in controlling the development of inflammatory diseases such as multiple sclerosis, possibly through differential engagement with ICAM-1 ligands such as Mac-1.
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Affiliation(s)
- Xianzhen Hu
- Department of Microbiology University of Alabama at Birmingham, Birmingham, AL, USA 35294
| | - Scott R Barnum
- Department of Microbiology University of Alabama at Birmingham, Birmingham, AL, USA 35294
| | - Jillian E Wohler
- Department of Microbiology University of Alabama at Birmingham, Birmingham, AL, USA 35294
| | - Trenton R Schoeb
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA 35294
| | - Daniel C Bullard
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA 35294
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37
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Abstract
gammadelta T cells represent a small subpopulation of T cells expressing a restricted repertoire of T-cell receptors and, unlike alphabeta T cells, function more as cells of the innate immune system. These cells are found in skin and mucosal sites as well as secondary lymphoid tissues and frequently act as first line of defense sentinels. gammadelta T cells have been implicated in the pathogenesis of demyelinating disease, although little was known regarding their trafficking and effector functions. In this Mini-Review, we highlight recent studies demonstrating that gammadelta T cells migrate rapidly to the CNS during experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. gammadelta T-cell trafficking to the CNS is independent of beta(2)-integrins and occurs well before onset of clinical signs of disease, peaking early during the acute phase of disease. gammadelta T-cell-mediated production of inflammatory cytokines, including interferon-gamma and tumor necrosis factor-alpha, appears critical for EAE development, suggesting that these cells may set the stage for activation of other subsets of infiltrating effector cells. These data suggest that gammadelta T cells or subsets of gammadelta T cells may represent a new therapeutic target in demeylinating disease.
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Affiliation(s)
- Jillian E Wohler
- Department of Microbiology, University of Alabama, Birmingham, Alabama, USA
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38
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Abstract
The beta(2)-integrins are a subfamily of integrins expressed on leukocytes that play an essential role in leukocyte trafficking, activation, and many other functions. Studies in EAE, the animal model for multiple sclerosis, show differential requirements for beta(2)-integrins in this disease model, ranging from critical in the case of LFA-1 (CD11a/CD18) to unimportant in the case of CD11d/CD18. Importantly, expression of beta(2)-integrins on T cell subsets provides some clues as to the function(s) these adhesion molecules play in disease development. For example, transferred EAE studies have shown that Mac-1 (CD11b/CD18) expression on alphabeta T cells is critical for disease development, and the absence of LFA-1 on Tregs in recipient mice results in exacerbated disease. In this review, we summarize recent findings regarding the role of beta(2)-integrins in demyelinating disease and new information about the role of beta(2)-integrins with respect to alterations in Treg numbers and function. In addition, we discuss the potential for targeting beta(2)-integrins in human demyelinating disease in light of the recent animal model studies.
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Affiliation(s)
- Xianzhen Hu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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39
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Abstract
We have previously shown that gammadelta T cells traffic to the CNS during EAE with concurrently increased expression of beta(2)-integrins and production of IFN-gamma and TNF-alpha. To extend these studies, we transferred bioluminescent gammadelta T cells to WT mice and followed their movement through the acute stages of disease. We found that gammadelta T cells rapidly migrated to the site of myelin oligodendrocyte glycoprotein peptide injection and underwent massive expansion. Within 6 days after EAE induction, bioluminescent gammadelta T cells were found in the spinal cord and brain, peaking in number between days 10 and 12 and then rapidly declining by day 15. Reconstitution of gammadelta T cell(-/-) mice with gammadelta T cells derived from beta(2)-integrin-deficient mice (CD11a, -b or -c) demonstrated that gammadelta T-cell trafficking to the CNS during EAE is independent of this family of adhesion molecules. We also examined the role of gammadelta T-cell-produced IFN-gamma and TNF-alpha in EAE and found that production of both cytokines by gammadelta T cells was required for full development of EAE. These results indicate that gammadelta T cells are critical for the development of EAE and suggest a therapeutic target in demyelinating disease.
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Affiliation(s)
- Jillian E Wohler
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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40
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Brambilla R, Persaud T, Hu X, Karmally S, Shestopalov VI, Dvoriantchikova G, Ivanov D, Nathanson L, Barnum SR, Bethea JR. Transgenic inhibition of astroglial NF-kappa B improves functional outcome in experimental autoimmune encephalomyelitis by suppressing chronic central nervous system inflammation. J Immunol 2009; 182:2628-40. [PMID: 19234157 DOI: 10.4049/jimmunol.0802954] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In the CNS, the transcription factor NF-kappaB is a key regulator of inflammation and secondary injury processes. Following trauma or disease, the expression of NF-kappaB-dependent genes is activated, leading to both protective and detrimental effects. In this study, we show that transgenic inactivation of astroglial NF-kappaB (glial fibrillary acidic protein-IkappaB alpha-dominant-negative mice) resulted in reduced disease severity and improved functional recovery following experimental autoimmune encephalomyelitis. At the chronic stage of the disease, transgenic mice exhibited an overall higher presence of leukocytes in spinal cord and brain, and a markedly higher percentage of CD8(+)CD122(+) T regulatory cells compared with wild type, which correlated with the timing of clinical recovery. We also observed that expression of proinflammatory genes in both spinal cord and cerebellum was delayed and reduced, whereas the loss of neuronal-specific molecules essential for synaptic transmission was limited compared with wild-type mice. Furthermore, death of retinal ganglion cells in affected retinas was almost abolished, suggesting the activation of neuroprotective mechanisms. Our data indicate that inhibiting NF-kappaB in astrocytes results in neuroprotective effects following experimental autoimmune encephalomyelitis, directly implicating astrocytes in the pathophysiology of this disease.
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Affiliation(s)
- Roberta Brambilla
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 Northwest 14th Terrace, Miami, FL 33136, USA.
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41
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Bethea JR, Brambilla R, Shestopalov VI, Barnum SR. Transgenic inhibition of astroglial NF-κB improves functional recovery in EAE by suppressing chronic neuroinflammation. (50.7). The Journal of Immunology 2009. [DOI: 10.4049/jimmunol.182.supp.50.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
In the CNS the transcription factor NF-κB is a key regulator of inflammation and secondary injury processes. Following trauma or disease, the expression of NF-κB-dependent genes is activated, leading to both protective and detrimental effects. Here we show that transgenic inactivation of astroglial NF-κB (GFAP-IκBα-dn mice) resulted in reduced disease severity and improved functional recovery following experimental autoimmune encephalomyelitis (EAE). At the chronic stage of the disease, transgenic mice exhibited an overall higher presence of leukocytes in spinal cord and brain, and a markedly higher percentage of CD8+CD122+ T regulatory cells compared to WT, which correlated with the timing of clinical recovery. We also observed that expression of proinflammatory genes in both spinal cord and cerebellum was delayed and reduced, while the loss of neuronal-specific molecules essential for synaptic transmission was limited compared to WT mice. Furthermore, death of retinal ganglion cells in affected retinas was almost abolished, suggesting the activation of neuroprotective mechanisms. Our data indicate that inhibiting NF-κB in astrocytes results in neuroprotective effects following EAE, directly implicating astrocytes in the pathophysiology of this disease.
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Affiliation(s)
| | | | | | - Scott R Barnum
- 3Microbiology, University of Alabama at Birmingham, Birmingham, Alabama
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42
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Osmers I, Smith SS, Parks BW, Yu S, Srivastava R, Wohler JE, Barnum SR, Kabarowski JHS. Deletion of the G2A receptor fails to attenuate experimental autoimmune encephalomyelitis. J Neuroimmunol 2009; 207:18-23. [PMID: 19135725 DOI: 10.1016/j.jneuroim.2008.11.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Accepted: 11/24/2008] [Indexed: 11/19/2022]
Abstract
Lysophosphatidylcholine (LPC) is a chemotactic lysolipid produced during inflammation by the hydrolytic action of phospholipase A(2) enzymes. LPC stimulates chemotaxis of T cells in vitro through activation of the G protein-coupled receptor, G2A. This has led to the proposition that G2A contributes to the recruitment of T cells to sites of inflammation and thus promotes chronic inflammatory autoimmune diseases associated with the generation and subsequent tissue infiltration of auto-antigen-specific effector T cells. However, one study suggests that G2A may negatively regulate T cell proliferative responses to antigen receptor engagement and thereby attenuates autoimmunity by reducing the generation of autoreactive T cells. To address the relative contribution of these G2A-mediated effects to the pathophysiology of T cell-mediated autoimmune disease, we examined the impact of G2A inactivation on the onset and severity of murine experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS). Wild type (G2A(+/+)) and G2A-deficient (G2A(-/-)) C57BL/6J mice exhibited a similar incidence and onset of disease following immunization with MOG(35-55) peptide. Disease severity was only moderately reduced in G2A(-/-) mice. Similar numbers of MOG(35-55) specific T cells were generated in secondary lymphoid organs of MOG(35-55)-immunized G2A(+/+) and G2A(-/-) mice. Comparable numbers of T cells were detected in spinal cords of G2A(+/+) and G2A(-/-) mice. We conclude that the proposed anti-proliferative and chemotactic functions of G2A are not manifested in vivo and therefore therapeutic targeting of G2A is unlikely to be beneficial in the treatment of MS.
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MESH Headings
- Animals
- CD4-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/immunology
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/physiology
- Cell Proliferation/drug effects
- Encephalomyelitis, Autoimmune, Experimental/chemically induced
- Encephalomyelitis, Autoimmune, Experimental/genetics
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Flow Cytometry/methods
- Gene Deletion
- Glycoproteins/adverse effects
- Interferon-gamma/metabolism
- Lymph Nodes/drug effects
- Lymph Nodes/immunology
- Lymph Nodes/pathology
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Myelin-Oligodendrocyte Glycoprotein
- Peptide Fragments/adverse effects
- Receptors, G-Protein-Coupled/deficiency
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/physiology
- Spleen/cytology
- Spleen/immunology
- Spleen/pathology
- T-Lymphocytes/immunology
- Time Factors
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Affiliation(s)
- Inga Osmers
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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43
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Dugger KJ, Zinn KR, Weaver C, Bullard DC, Barnum SR. Effector and suppressor roles for LFA-1 during the development of experimental autoimmune encephalomyelitis. J Neuroimmunol 2008; 206:22-7. [PMID: 19010554 DOI: 10.1016/j.jneuroim.2008.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 10/14/2008] [Indexed: 01/10/2023]
Abstract
LFA-1 (CD11a/CD18) is a member of the beta(2)-integrin family of adhesion molecules important in leukocyte trafficking and activation. Although LFA-1 is thought to contribute to the development of experimental autoimmune encephalomyelitis (EAE) primarily through its functions on effector T cells, its importance on other leukocyte populations remains unexplored. To address this question, we performed both adoptive transfer EAE experiments involving CD11a(-/-) mice and trafficking studies using bioluminescent T cells expressing luciferase under the control of a CD2 promoter (T-lux cells). Transfer of encephalitogenic CD11a(-/-) T cells to wild type mice resulted in a significant reduction in overall EAE severity compared to control transfers. We also observed, using in vivo imaging techniques, that CD11a(-/-) T-lux cells readily infiltrated lymph nodes and the CNS of wild type recipients with kinetics comparable to CD11a(+/+) transfers, although their overall numbers in these organs were reduced. Surprisingly, transfer of encephalitogenic wild type T cells to CD11a(-/-) mice induced a severe and sometimes fatal EAE disease course, associated with massive T cell infiltration and proliferation in the CNS. These data indicate that LFA-1 expression on leukocytes in recipient mice plays an important immunomodulatory role in EAE. Thus, LFA-1 acts as a key regulatory adhesion molecule during the development of EAE, serving both pro- and anti-inflammatory roles in disease pathogenesis.
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Affiliation(s)
- Kari J Dugger
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
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44
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Abstract
Purification of lymphocytes, particularly T cells, is commonly performed using nylon wool. This enrichment method selectively retains B cells and some myeloid cells allowing a significantly more pure T cell population to flow through a nylon wool column. T cells purified in this fashion are assumed to be unaltered and functionally naïve, however some studies have suggested aberrant in vitro T cell responses after nylon wool treatment. We found that nylon wool purification significantly altered T cell proliferation, expression of activation markers and production of cytokines. Our results suggest that nylon wool treatment modifies T cell activation responses and that caution should be used when choosing this purification method.
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Affiliation(s)
- Jillian E Wohler
- Department of Microbiology, University of Alabama, Birmingham, Birmingham, AL 35294, USA
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45
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Smith SS, Ludwig M, Wohler JE, Bullard DC, Szalai AJ, Barnum SR. Deletion of both ICAM-1 and C3 enhances severity of experimental autoimmune encephalomyelitis compared to C3-deficient mice. Neurosci Lett 2008; 442:158-60. [PMID: 18634851 DOI: 10.1016/j.neulet.2008.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 07/01/2008] [Accepted: 07/02/2008] [Indexed: 12/19/2022]
Abstract
Multiple sclerosis (MS) is an autoimmune disease characterized by central nervous system (CNS) inflammation and leukocyte infiltration, demyelination of neurons, and blood-brain barrier breakdown. The development of experimental autoimmune encephalomyelitis (EAE), the animal model for MS is dependent on a number of components of the immune system including complement and adhesion molecules. Previous studies in our lab have examined the role of C3, the central complement component, and intercellular adhesion molecule-1 (ICAM-1) a key cell adhesion molecule involved in leukocyte trafficking to sites of inflammation including the CNS. In these studies we demonstrated that myelin oligodendrocyte glycoprotein (MOG)-induced EAE is markedly attenuated in both ICAM-1(-/-) and C3(-/-) mice. Given the pivotal role that these proteins play in EAE, we hypothesized that EAE in ICAM-1(-/-) and C3(-/-) double mutant mice would likely fail to develop. Unexpectedly, EAE in ICAM-1(-/-)xC3(-/-) mice was only modestly attenuated compared to wild type mice and significantly worse than C3(-/-) mice. Leukocyte infiltration was commensurate with disease severity between the three groups of mice. Spinal cord T cells from ICAM-1(-/-)xC3(-/-) mice produced the highest levels of IFN-gamma and TNF-alpha, despite reduced disease severity compared to wild type mice. The mechanisms behind the elevated EAE severity in ICAM-1(-/-)xC3(-/-) mice may relate to altered homing of leukocytes or processing of self-antigens in the double mutant background.
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Affiliation(s)
- Sherry S Smith
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
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46
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Henson BJ, Pennington LE, Watson LE, Barnum SR. Excision of the nifD element in the heterocystous cyanobacteria. Arch Microbiol 2008; 189:357-66. [PMID: 18283436 DOI: 10.1007/s00203-007-0326-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 10/17/2007] [Accepted: 11/02/2007] [Indexed: 11/30/2022]
Abstract
Heterocyst differentiation in cyanobacteria is accompanied by developmentally regulated DNA rearrangements that occur within the nifD, fdxN, and hupL genes. These genetic elements are excised from the genome by site-specific recombination during the latter stages of differentiation. The nifD element is excised by the recombinase, XisA, located within the element. Our objective was to examine the XisA-mediated excision of the nifD element. To accomplish this, we observed the ability of XisA to excise substrate plasmids that contained the flanking regions of the nifD element in an E. coli host. Using PCR directed mutagenesis, nucleotides in the nifD element flanking regions in substrate plasmids were altered and the effect on recombination was determined. Results indicate that only certain nucleotides within and surrounding the direct repeats are involved in excision. In some nucleotide positions, the presence of a purine versus a pyrimidine greatly affected recombination. Our results also indicated that the site of excision and branch migration occurs in a 6 bp region within the direct repeats.
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Affiliation(s)
- B J Henson
- Graduate School of Public Health, Department of Human Genetics, University of Pittsburgh, 315 Paran Hall, 130 De Soto St, Pittsburgh, PA 15261, USA
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47
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Abstract
The complement system, an important part of the innate immune system, provides protection against invading pathogens, in part through its proinflammatory activities. Although most complement proteins are synthesized locally in the brain and the relevant complement receptors are expressed on resident brain cells, little is known about brain-specific role(s) of the complement system. C3a and C5a, complement-derived peptides with anaphylatoxic properties, have been implicated in noninflammatory functions, such as tissue regeneration and neuroprotection. Recently, we have shown that signaling through C3a receptor (C3aR) is involved in the regulation of neurogenesis. In the present study, we assessed basal neurogenesis in mice lacking C5a receptor (C5aR(-/-)) and mice expressing C3a and C5a, respectively in the CNS under the control of glial fibrillary acidic protein (GFAP) promoter (C3a/GFAP and C5a/GFAP, respectively) and thus without the requirement for complement activation. We did not observe any difference among C5aR(-/-), C3a/GFAP and C5a/GFAP mice and their respective controls in the number of newly formed neuroblasts and newly formed neurons in the subventricular zone (SVZ) of lateral ventricles and hippocampal dentate gyrus, the two neurogenic niches in the adult brain, or the olfactory bulb, the final destination of new neurons formed in the SVZ. Our results indicate that signaling through C5aR is not involved in basal neurogenesis in adult mice and that basal neurogenesis in adult C3a/GFAP and C5a/GFAP mice is not altered.
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Affiliation(s)
- Yalda Rahpeymai Bogestål
- Department of Medical Chemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy at Göteborg University, Göteborg, Sweden
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48
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Briggs DT, Martin CB, Ingersoll SA, Barnum SR, Martin BK. Astrocyte-specific expression of a soluble form of the murine complement control protein Crry confers demyelination protection in the cuprizone model. Glia 2007; 55:1405-15. [PMID: 17674370 DOI: 10.1002/glia.20551] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Complement has been implicated as a potential effector mechanism in neurodegeneration; yet the precise role of complement in this process remains elusive. In this report, we have utilized the cuprizone model of demyelination-remyelination to examine the contribution of complement to disease. C1q deposition was observed in the corpus callosum of C57BL/6 mice during demyelination, suggesting complement activation by apoptotic oligodendrocyte debris. Simultaneously, these mice lost expression of the rodent complement regulatory protein, Crry. A soluble CNS-specific form of the Crry protein (sCrry) expressed in a transgenic mouse under the control of an astrocyte-specific promoter was induced in the corpus callosum during cuprizone treatment. Expression of this protein completely protected the mice from demyelination. Interestingly, sCrry mice had low levels of demyelination at later times when control mice were remyelinating. Although the sCrry transgenic mice had lower levels of demyelination, there was no decrease in overall cellularity, however there were decreased numbers of microglia in the sCrry mice relative to controls. Strikingly, sCrry mice had early recovery of mature oligodendrocytes, although they later disappeared. TUNEL staining suggested that production of the sCrry protein in the transgenic mice protected from a late apoptosis event at 3 weeks of cuprizone treatment. Our data suggest complement provides some protection of mature oligodendrocytes during cuprizone treatment but may be critical for subsequent remyelination events. These data suggest that temporal restriction of complement inhibition may be required in some disease settings.
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MESH Headings
- Animals
- Apoptosis/physiology
- Astrocytes/immunology
- Astrocytes/metabolism
- Brain/immunology
- Brain/metabolism
- Brain/physiopathology
- Chelating Agents
- Complement System Proteins/immunology
- Complement System Proteins/metabolism
- Corpus Callosum/immunology
- Corpus Callosum/metabolism
- Corpus Callosum/physiopathology
- Cuprizone
- Cytoprotection/genetics
- Demyelinating Autoimmune Diseases, CNS/chemically induced
- Demyelinating Autoimmune Diseases, CNS/genetics
- Demyelinating Autoimmune Diseases, CNS/immunology
- Disease Models, Animal
- Glial Fibrillary Acidic Protein/genetics
- Gliosis/genetics
- Gliosis/immunology
- Gliosis/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Nerve Regeneration/genetics
- Oligodendroglia/immunology
- Receptors, Complement/genetics
- Receptors, Complement/immunology
- Receptors, Complement/metabolism
- Receptors, Complement 3b
- Time Factors
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Affiliation(s)
- Dustin T Briggs
- Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242, USA
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49
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Smith SS, Barnum SR. Differential expression of beta 2-integrins and cytokine production between gammadelta and alphabeta T cells in experimental autoimmune encephalomyelitis. J Leukoc Biol 2007; 83:71-9. [PMID: 17928460 DOI: 10.1189/jlb.0407263] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The expression of beta 2-integrins on gammadelta T cells in naïve mice or those with experimental autoimmune encephalomyelitis (EAE) remains poorly characterized. We compared beta 2-integrin expression and cytokine production between gammadelta and alphabeta T cells over the acute course of EAE. We observed that unlike in alphabeta T cells, beta 2-integrin expression on gammadelta T cells increased significantly from baseline, peaked at Day 10, and remained unchanged in the draining lymph nodes or declined in the spleen and CNS by Day 15. In addition, IFN-gamma- and TNF-alpha-producing gammadelta T cells infiltrated the CNS rapidly and produced significantly more of these cytokines than alphabeta T cells throughout the course of EAE. These results suggest unique roles for beta 2-integrins in the trafficking of gammadelta versus alphabeta T cells during EAE and that gammadelta T cells infiltrate the CNS rapidly, producing cytokines, which modulate acute disease.
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Affiliation(s)
- Sherry S Smith
- Department of Microbiology, University of Alabama at Birmingham, 845 19th St. S., BBRB/842, Birmingham, AL 35294, USA
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50
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Bullard DC, Hu X, Adams JE, Schoeb TR, Barnum SR. p150/95 (CD11c/CD18) expression is required for the development of experimental autoimmune encephalomyelitis. Am J Pathol 2007; 170:2001-8. [PMID: 17525267 PMCID: PMC1899456 DOI: 10.2353/ajpath.2007.061016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
p150/95 (CD11c/CD18, CR4) is a member of the beta(2)-integrin family of adhesion molecules and is considered an important phagocytic receptor. The role of p150/95 in the development of central nervous system demyelinating diseases, including multiple sclerosis, remains unexplored. To determine p150/95-mediated mechanisms in experimental autoimmune encephalomyelitis (EAE), we performed EAE using CD11c-deficient (CD11c(-/-)) mice. EAE in CD11c(-/-) mice was significantly attenuated and characterized by markedly reduced spinal cord T-cell infiltration and interferon-gamma production by these cells. Adoptive transfer of antigen-restimulated T cells from wild-type to CD11c(-/-) mice produced significantly attenuated EAE, whereas transfer of CD11c(-/-) antigen-restimulated T cells to control mice induced a very mild, monophasic EAE. T cells from MOG(35-55) peptide-primed CD11c(-/-) mice displayed an unusual cytokine phenotype with elevated levels of interleukin (IL)-2, IL-4, and IL-12 but reduced levels of interferon-gamma, tumor necrosis factor-alpha, IL-10, IL-17, and transforming growth factor-beta compared with control mice. Overall, CD11c(-/-) T cells from primed mice proliferated comparably to that of control T cells on MOG(35-55) restimulation. Our results indicate that expression of p150/95 is critical on both T cells as well as other leukocytes for the development of demyelinating disease and may represent a novel therapeutic target for multiple sclerosis.
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Affiliation(s)
- Daniel C Bullard
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street S., Birmingham, AL 35294, USA
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