bluuebunny/crossref_metadata_2025_split huggingface dataset:
Redundancy in Antigen-Presenting Function of the HLA-DR and -DQ Molecules in the Multiple Sclerosis-Associated HLA-DR2 Haplotype
Authors: Sospedra Mireia , Muraro Paolo A. , Stefanová Irena , Zhao Yingdong , Chung Katherine , Li Yili , Giulianotti Marc , Simon Richard , Mariuzza Roy , Pinilla Clemencia , Martin Roland 
Published: April 2014

Abstract
The three HLA class II alleles of the DR2 haplotype, DRB1*1501, DRB5*0101, and DQB1*0602, are in strong linkage disequilibrium and confer most of the genetic risk to multiple sclerosis. Functional redundancy in Ag presentation by these class II molecules would allow recognition by a single TCR of identical peptides with the different restriction elements, facilitating T cell activation and providing one explanation how a disease-associated HLA haplotype could be linked to a CD4+ T cell-mediated autoimmune disease. Using combinatorial peptide libraries and B cell lines expressing single HLA-DR/DQ molecules, we show that two of five in vivo-expanded and likely disease-relevant, cross-reactive cerebrospinal fluid-infiltrating T cell clones use multiple disease-associated HLA class II molecules as restriction elements. One of these T cell clones recognizes &gt;30 identical foreign and human peptides using all DR and DQ molecules of the multiple sclerosis-associated DR2 haplotype. A T cell signaling machinery tuned for efficient responses to weak ligands together with structural features of the TCR-HLA/peptide complex result in this promiscuous HLA class II restriction.
Effacing of the T Cell Compartment by Cardiac Transplantation in Infancy
Authors: Ogle Brenda M. , West Lori J. , Driscoll David J. , Strome Scott E. , Razonable Raymund R. , Paya Carlos V. , Cascalho Marilia , Platt Jeffrey L. 
Published: April 2014

AbstractFor cardiac transplantation in infants, T cells are depleted and the thymus is removed. These manipulations should cause profound defects in the T cell compartment. To test this concept, 20 subjects who underwent cardiac transplantation in infancy and healthy age-matched subjects were studied. The number of T cells in the blood was nearly normal in all subjects 1–10 years after surgery. However, newly generated T cells were undetectable in 10 recipients and 10-fold less than controls in 10, suggesting absence of thymic function. TCRβ chain diversity, measured by a novel technique, was ∼100-fold lower than controls. T cell function, deduced from levels of human herpesvirus 7 and response to hepatitis B immunization, were notably impaired. Yet cardiac transplant recipients were generally free of opportunistic infections. Our findings demonstrate a novel approach to measuring lymphocyte diversity and suggest that understanding how these subjects resist infection could yield important insights into immune fitness.
Identification of an Epitope within Human Integrin α6 Subunit for the Binding of Autoantibody and Its Role in Basement Membrane Separation in Oral Pemphigoid
Authors: Rashid Khwaja Aftab , Stern Joel N. H. , Ahmed A. Razzaque 
Published: April 2014

Abstract
Oral pemphigoid (OP) is a rare chronic autoimmune disease characterized by blisters and erosive lesions in the oral mucosa. We identified an epitope for the binding of OP autoantibodies within the integrin α6 subunit, by cloning four overlapping fragments (A, B, C, and D). Immunoperoxidase studies demonstrated that all of the fragments were present in the oral mucosa. Sera of 20 patients with active OP were studied. All sera bound to integrin α6 in DU145 cell lysate by immunoprecipitation and immunoblot assay. The same sera bound only to fragment A and its subfragment A2 on an immunoblot assay. The specificity of the binding was further characterized by blocking and cross-absorption studies. A 14-aa synthetic peptide A2.1, within fragment A2, bound to all the test sera. The sera in this study bound to only one epitope. Controls were sera samples from 10 healthy volunteers and 40 patients with other variants of mucous membrane pemphigoid and mAb GoH3 and BQ16 to integrin α6. Control sera did not bind to the full-length integrin α6 subunit nor any of the cloned fragments. The OP patient sera and immunoaffinity-purified OP sera, rabbit antisera against fragments A and A2, and mAb GoH3 produced basement membrane separation of oral mucosa in organ culture. This study identifies a peptide within the extracellular domain of integrin α6 molecule, to which Abs in the sera from patients with OP bind, and which may play an important role in the pathogenesis of OP.
TLR9 Activation Is Defective in Common Variable Immune Deficiency
Authors: Cunningham-Rundles Charlotte , Radigan Lin , Knight Adina K. , Zhang Li , Bauer Laura , Nakazawa Atsushi 
Published: April 2014

Abstract
Common variable immune deficiency (CVID) is a primary immune deficiency characterized by low levels of serum immune globulins, lack of Ab, and reduced numbers of CD27+ memory B cells. Although T, B, and dendritic cell defects have been described, for the great majority, genetic causes have not been identified. In these experiments, we investigated B cell and plasmacytoid dendritic cell activation induced via TLR9, an intracellular recognition receptor that detects DNA-containing CpG motifs from viruses and bacteria. CpG-DNA activates normal B cells by the constitutively expressed TLR9, resulting in cytokine secretion, IgG class switch, immune globulin production, and potentially, the preservation of long-lived memory B cells. We found that CpG-DNA did not up-regulate expression of CD86 on CVID B cells, even when costimulated by the BCR, or induce production of IL-6 or IL-10 as it does for normal B cells. TLR9, found intracytoplasmically and on the surface of oligodeoxynucleotide-activated normal B cells, was deficient in CVID B cells, as was TLR9 mRNA. TLR9 B cell defects were not related to proportions of CD27+ memory B cells. CpG-activated CVID plasmacytoid dendritic cells did not produce IFN-α in normal amounts, even though these cells contained abundant intracytoplasmic TLR9. No mutations or polymorphisms of TLR9 were found. These data show that there are broad TLR9 activation defects in CVID which would prevent CpG-DNA-initiated innate immune responses; these defects may lead to impaired responses of plasmacytoid dendritic cells and loss of B cell function.
Allelic Variation in Key Peptide-Binding Pockets Discriminates between Closely Related Diabetes-Protective and Diabetes-SusceptibleHLA-DQB1*06Alleles
Authors: Ettinger Ruth A. , Papadopoulos George K. , Moustakas Antonis K. , Nepom Gerald T. , Kwok William W. 
Published: April 2014

AbstractHLA-DQA1*0102-DQB1*0602 is associated with protection against type 1 diabetes (T1D). A similar allele, HLA-DQA1*0102-DQB1*0604, contributes to T1D susceptibility in certain populations but differs only at seven amino acids from HLA-DQA1*0102-DQB1*0602. Five of these polymorphisms are found within the peptide-binding groove, suggesting that differences in peptide binding contribute to the mechanism of their association with T1D. In this study, we determine the peptide-binding motif for HLA-DQA1*0102-DQB1*0604 allelic protein (DQ0604) in comparison to the established HLA-DQA1*0102-DQB1*0602 (DQ0602) motif using binding assays with model peptides from T1D autoantigens and homology modeling using the coordinates of the DQ0602-hypocretin 1–13 crystal structure. The peptide binding preferences were deduced with a peptide from insulin that bound both with a 2- to 3-fold difference in avidity using the same amino acids in the peptide as anchors. Peptide binding differences directly influenced by the polymorphisms in or nearby pockets 1, 6, and 9 were observed. In pocket 1, DQ0604 was better able to accommodate aromatic residues due to the β86 and β87 polymorphisms. A negatively charged amino acid was preferred by DQ0604 in pocket 6 due to the positively charged β30His. In pocket 9, DQ0604 preferred aromatic amino acids due to the β9 and β30 polymorphisms and had low tolerance of acidic residues. β57Val in DQ0604 functions differently than β57Ala, in that it pushes α76Arg outside of the pocket, preventing the formation of a salt bridge with an acidic amino acid in the peptide. This study furthers our understanding of the structure-function relationships of MHC class II polymorphisms.
Predicting Tumor Outcome following Cancer Vaccination by Monitoring Quantitative and Qualitative CD8+ T Cell Parameters
Authors: Rosato Antonio , Zoso Alessia , Santa Silvia Dalla , Milan Gabriella , Del Bianco Paola , De Salvo Gian Luca , Zanovello Paola 
Published: April 2014

Abstract
Identification of reliable surrogate predictors for evaluation of cancer vaccine efficacy is a critical issue in immunotherapy. We analyzed quantitative and qualitative CD8+ T cell parameters in a large pool of BALB/c mice that were DNA-vaccinated against P1A self tumor-specific Ag. After immunization, mice were splenectomized and kept alive for a subsequent tumor challenge to correlate results of immune monitoring assays with tumor regression or progression in each individual animal, and to assess the prognostic value of the assays. The parameters tested were 1) percentage of in vivo vaccine-induced tumor-specific CD8+ T cells; 2) results of ELISPOT tests from fresh splenocytes; 3) percentage of tumor-specific CD8+ T cells in culture after in vitro restimulation; 4) in vitro increase of tumor-specific CD8+ T cell population expressed as fold of expansion; and 5) antitumor lytic activity of restimulated cultures. Except for the ELISPOT assay, each parameter tested was shown by univariate statistical analysis to correlate with tumor regression. However, multivariate analysis revealed that only in vitro percentage of Ag-specific CD8+ T cells was an independent prognostic factor that predicted tumor outcome. These findings should be considered in the design of new immune monitoring systems used in cancer immunotherapy studies.
Pretreatment Intracerebral and Peripheral Blood Immune Responses in Vietnamese Adults with Tuberculous Meningitis: Diagnostic Value and Relationship to Disease Severity and Outcome
Authors: Simmons Cameron P. , Thwaites Guy E. , Quyen Nguyen Than Ha , Torok Estee , Hoang Dang Minh , Chau Tran Thi Hong , Mai Pham Phuong , Lan Nguyen Thi Ngoc , Dung Nguyen Huy , Quy Hoang Thi , Bang Nguyen Duc , Hien Tran Tinh , Farrar Jeremy 
Published: April 2014

Abstract
Tuberculous meningitis (TBM) is the most devastating form of tuberculosis. Both intracerebral and peripheral blood immune responses may be relevant to pathogenesis, diagnosis, and outcome. In this study, the relationship between pretreatment host response, disease phenotype, and outcome in Vietnamese adults with TBM was examined. Before treatment, peripheral blood IFN-γ ELISPOT responses to the Mycobacterium tuberculosis Ags ESAT-6, CFP-10, and purified protein derivative (PPD) were a poor diagnostic predictor of TBM. Cerebrospinal fluid IL-6 concentrations at presentation were independently associated with severe disease presentation, suggesting an immunological correlate of neurological damage before treatment. Surprisingly however, elevated cerebrospinal fluid inflammatory cytokines were not associated with death or disability in HIV-negative TBM patients at presentation. HIV coinfection attenuated multiple cerebrospinal fluid inflammatory indices. Low cerebrospinal fluid IFN-γ concentrations were independently associated with death in HIV-positive TBM patients, implying that IFN-γ contributes to immunity and survival. Collectively, these results reveal the effect of HIV coinfection on the pathogenesis of TBM and suggest that intracerebral immune responses, at least in HIV-negative cases, may not be as intimately associated with disease outcome as previously thought.
Autoreactive T and B Cells from Bullous Pemphigoid (BP) Patients Recognize Epitopes Clustered in Distinct Regions of BP180 and BP230
Authors: Thoma-Uszynski Sybille , Uter Wolfgang , Schwietzke Susanne , Schuler Gerold , Borradori Luca , Hertl Michael 
Published: April 2014

AbstractBullous pemphigoid (BP) is a well-characterized model of autoantibody-mediated autoimmunity, which presumably depends on autoreactive Th cells that promote the activation of autoreactive B cells. The two major autoantigens of BP are BP180 and BP230, two components of dermoepidermal adhesion complexes. Both, autoreactive Th cell responses and autoantibody profiles were characterized in 35 patients with acute onset BP using BP180 and BP230 proteins. Our findings indicate the following: 1) autoreactive Th cells recognized epitopes within the NH2-terminal (77.1%), COOH-terminal (65.7%), and central portion (57.1%) of the BP180 ectodomain; 2) IgG autoantibodies were found to exhibit similar or identical reactivity against the NH2-terminal (82.8%), COOH-terminal (77.1%), and central portion (37.1%) of the BP180 ectodomain; 3) T and B cell reactivity with the NH2-terminal portion of the BP180 ectodomain was associated with extensive BP, whereas the central portion was more frequently recognized in limited BP; 4) only 7 of 16 (43.7%) and 6 of 16 (37.5%) BP patients showed a Th cellular response against the COOH- and NH2-terminal regions of BP230, respectively, whereas 5) IgG reactivity against the COOH- and NH2-termini of BP230 was detected in 5 of 16 (31.3%) and 6 of 16 (37.5%) patients, respectively. These results demonstrate that Th and B cell reactivities against BP180, are, in contrast to BP230 reactivity, almost constantly detectable in BP patients, and differential epitope recognition of BP180 seems to be associated with distinct clinical severity. These observations support the concept that BP180, but not BP230, is the primary autoantigen of BP critical for disease development.
Mechanisms of Immunopathology in Murine Models of Central Nervous System Demyelinating Disease
Authors: Ercolini Anne M. , Miller Stephen D. 
Published: April 2014

AbstractMany disorders of the CNS, such as multiple sclerosis (MS), are characterized by the loss of the myelin sheath surrounding nerve axons. MS is associated with infiltration of inflammatory cells into the brain and spinal cord, which may be the primary cause of demyelination or which may be induced secondary to axonal damage. Both the innate and adaptive arms of the immune system have been reported to play important roles in myelin destruction. Numerous murine demyelinating models, both virus-induced and/or autoimmune, are available, which reflect the clinical and pathological variability seen in human disease. This review will discuss the immunopathologic mechanisms involved in these demyelinating disease models.
Cutting Edge: Anti-CD25 Monoclonal Antibody Injection Results in the Functional Inactivation, Not Depletion, of CD4+CD25+ T Regulatory Cells
Authors: Kohm Adam P. , McMahon Jeffrey S. , Podojil Joseph R. , Begolka Wendy Smith , DeGutes Mathew , Kasprowicz Deborah J. , Ziegler Steven F. , Miller Stephen D. 
Published: April 2014

Abstract
CD4+CD25+ T regulatory (TR) cells are an important regulatory component of the adaptive immune system that limit autoreactive T cell responses in various models of autoimmunity. This knowledge was generated by previous studies from our lab and others using TR cell supplementation and depletion. Contrary to dogma, we report here that injection of anti-CD25 mAb results in the functional inactivation, not depletion, of TR cells, resulting in exacerbated autoimmune disease. Supporting this, mice receiving anti-CD25 mAb treatment display significantly lower numbers of CD4+CD25+ T cells but no change in the number of CD4+FoxP3+ TR cells. In addition, anti-CD25 mAb treatment fails to both reduce the number of Thy1.1+ congenic CD4+CD25+ TR cells or alter levels of CD25 mRNA expression in treatment recipients. Taken together, these findings have far-reaching implications for the interpretation of all previous studies forming conclusions about CD4+CD25+ TR cell depletion in vivo.
Cutting Edge: CD28 Controls Dominant Regulatory T Cell Activity during Active Immunization
Authors: Lyddane Clay , Gajewska Beata U. , Santos Elmer , King Philip D. , Furtado Glaucia C. , Sadelain Michel 
Published: April 2014

Abstract
Ligation of CD28 during Ag recognition plays an important role in the generation of effective T cell responses. However, its peripheral control of regulatory T cell function remains obscure. In this study, we show that naive wild-type or CD28−/− CD4+CD25− T cells exposed to peptide in vivo develop regulatory activity that suppresses the response of adoptively transferred naive T cells to a subsequent immunogenic challenge. We find that although CD28 is engaged during the initial peptide-priming event and is essential to sustain T cell survival, it is not sufficient to prevent the dominance of regulatory T cell function. Immunization with adjuvant abrogates regulatory dominance, reducing overall Foxp3 expression in a CD28-dependent manner. We conclude that CD28 licenses active immunization by regulating Ag-induced immunoregulation.
Cutting Edge: Hormonal Milieu, Not Antigenic Specificity, Determines the Mature Phenotype of Autoreactive B Cells
Authors: Venkatesh Jeganathan , Peeva Elena , Xu Xiaonan , Diamond Betty 
Published: April 2014

Abstract
Although both marginal zone and follicular B cells produce anti-DNA Abs in murine models of systemic lupus erythematosus, it has been unclear whether these distinct B cell subsets make identical or different Abs. Single-cell analysis demonstrates that the same DNA-reactive B cells can mature to either subset, depending on the hormonal environment. Anti-DNA B cells in estradiol-treated mice become marginal zone cells while identical cells from prolactin-treated mice become follicular cells. The B cell receptor signaling pathway is influenced by hormonal milieu. Thus, hormonal milieu and perhaps B cell receptor signaling, but not antigenic specificity, correlates with the differentiation pathway. These observations have implications for the pathogenesis and treatment of autoimmune disease.
Cutting Edge: The Direct Action of Type I IFN on CD4 T Cells Is Critical for Sustaining Clonal Expansion in Response to a Viral but Not a Bacterial Infection
Authors: Havenar-Daughton Colin , Kolumam Ganesh A. , Murali-Krishna Kaja 
Published: April 2014

Abstract
The action of type I IFN (IFN-I) on APCs is well studied, but their direct effect on CD4 T cells is unclear. To address this, we transferred IFN-I receptor-deficient (IFN-IR0) and -sufficient (wild-type, WT) TCR-transgenic CD4 T cells into WT mice and analyzed their response to immunization. In response to lymphocytic choriomeningitis virus immunization, WT CD4 T cells expanded ∼100-fold, whereas IFN-IR0 CD4 T cells expanded &lt;10-fold. However, both WT and IFN-IR0 CD4 T cells expanded ∼10-fold after Listeria monocytogenes immunization. Poor expansion of IFN-IR0 CD4 T cells after lymphocytic choriomeningitis virus immunization was not due to a defect in proliferation or initial activation but to poor survival of the daughter cells. Thus, direct IFN-I signals can play either a critical or minimal role in CD4 T cell clonal expansion depending on the specific pathogen.
TGF-β Requires CTLA-4 Early after T Cell Activation to Induce FoxP3 and Generate Adaptive CD4+CD25+ Regulatory Cells
Authors: Zheng Song Guo , Wang Ju Hua , Stohl William , Kim Kyoung Soo , Gray J. Dixon , Horwitz David A. 
Published: April 2014

Abstract
Although positive CD28 costimulation is needed for the generation of natural CD4+CD25+ regulatory T cells, we report that negative CTLA-4 costimulation is necessary for generating phenotypically and functionally similar adaptive CD4+CD25+ suppressor cells. TGF-β could not induce CD4+CD25− cells from CTLA-4−/− mice to express normal levels of FoxP3 or to develop suppressor activity. Moreover, blockade of CTLA-4 following activation of wild-type CD4+ cells abolished the ability of TGF-β to induce FoxP3-expressing mouse suppressor cells. TGF-β accelerated expression of CTLA-4, and time course studies suggested that CTLA-4 ligation of CD80 shortly after T cell activation enables TGF-β to induce CD4+CD25− cells to express FoxP3 and develop suppressor activity. TGF-β also enhanced CD4+ cell expression of CD80. Thus, CTLA-4 has an essential role in the generation of acquired CD4+CD25+ suppressor cells in addition to its other inhibitory effects. Although natural CD4+CD25+ cells develop normally in CTLA-4−/− mice, the lack of TGF-β-induced, peripheral CD4+CD25+ suppressor cells in these mice may contribute to their rapid demise.
Dendritic Cell Synthesis of C3 Is Required for Full T Cell Activation and Development of a Th1 Phenotype
Authors: Peng Qi , Li Ke , Patel Hetal , Sacks Steven H. , Zhou Wuding 
Published: April 2014

Abstract
Previous studies have found that deficiency of complement component C3 is associated with reduced T cell responses in several disease models including viral infection, autoimmune disease, and transplantation. However, the underlying mechanism is unclear. In this study, we demonstrate that dendritic cells (DCs) are able to synthesize C3 and this synthesis is required for the capacity of DCs to stimulate alloreactive T cell responses in vitro and in vivo. Compared with C3-producing DCs, C3-nonproducing DCs exhibit reduced potency to stimulate an alloreactive T cell response, favor the polarization of CD4+ T cells toward Th2 phenotype, and have regulatory T cell-driving capacity. In addition, priming mice with C3-deficient DCs compared with wild-type DCs led to delayed skin allograft rejection. Our findings that nonproduction of C3 by DCs significantly reduced T cell stimulation and impaired allograft rejection provide a potentially important explanation of how C3-deficient mice develop reduced T cell responses and of how C3-deficient donor kidney is protected from T cell-mediated graft rejection.
In Vitro Suppression of CD8+ T Cell Function by Friend Virus-Induced Regulatory T Cells
Authors: Robertson Shelly J. , Messer Ronald J. , Carmody Aaron B. , Hasenkrug Kim J. 
Published: April 2014

Abstract
Regulatory T cell (Treg)-mediated suppression of CD8+ T cells has been implicated in the establishment and maintenance of chronic viral infections, but little is known about the mechanism of suppression. In this study an in vitro assay was developed to investigate the suppression of CD8+ T cells by Friend retrovirus (FV)-induced Tregs. CD4+CD25+ T cells isolated from mice chronically infected with the FV suppressed the development of effector function in naive CD8+ T cells without affecting their ability to proliferate or up-regulate activation markers. In vitro restimulation was not required for suppression by FV-induced Tregs, correlating with their high activation state in vivo. Suppression was mediated by direct T cell-T cell interactions and occurred in the absence of APCs. Furthermore, suppression occurred irrespective of the TCR specificity of the CD8+ T cells. Most interestingly, FV-induced Tregs were able to suppress the function of CD8+ effector T cells that had been physiologically activated during acute FV infection. The ability to suppress the effector function of activated CTLs is likely a requisite role for Tregs in limiting immunopathology by CD8+ T cells during antiviral immune responses. Such activity may also have adverse consequences by allowing viruses to establish and maintain chronic infections if suppression of antiviral immune responses occurs before virus eradication.