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Immunodominant Epitope (immunodominant + epitope)
Selected AbstractsGetting to the crux of the matter: IL-23 and Th17 cell accumulation in the CNSEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2009Benjamin M. Segal Abstract IL-23 plays a critical role in EAE induced by the active immunization of C57BL/6 mice with an immunodominant epitope of myelin oligodendrocyte glycoprotein (MOG35,55). It was initially assumed that the pathogenic effects of IL-23 were directly related to the generation, expansion and/or stabilization of autoreactive CD4+ Th17 cells. However, a number of recent studies have uncovered discrepancies between the requirement for IL-23, as opposed to Th17 cells or their products (IL-17A, IL-17F and IL-22), in the development of EAE. In this issue of the European Journal of Immunology, it is demonstrated that impairment of IL-23 signaling does not impede the expansion of myelin-specific CD4+ T cells in peripheral lymphoid tissues but inhibits their accumulation in the CNS. This paper contributes to a growing body of data that implicates IL-23 in the acquisition of CNS homing properties by autoreactive effector cells. [source] Analysis of the mechanism for extracellular processing in the presentation of human immunodeficiency virus-1 envelope protein-derived peptide to epitope-specific cytotoxic T lymphocytesIMMUNOLOGY, Issue 1 2000Y. Nakagawa Summary An immunodominant epitope of human immunodeficiency virus-1 (HIV-1) gp160 recognized by Dd class I major histocompatibility complex (MHC) molecule-restricted, CD8+ cytotoxic T lymphocytes (CTL) was originally identified as a peptide composed of 15 amino acids (P18IIIB: RIQRGPGRAFVTIGK). However, further study has indicated that a 10-mer peptide, I-10 (RGPGRAFVTI), within P18IIIB is the minimal-sized epitope and the trimming step(s) of two carboxyl terminal amino acids (GK) is essential to produce I-10 from P18IIIB. In the processing, angiotensin-1-converting enzyme (ACE), found in sera, plays a central role in generating I-10. Target cells could be sensitized with I-10 under conditions where ACE activity in the sera was abrogated. In contrast, in the case of P18IIIB, requiring further processing to delete the C-terminus of two amino acids in order to act, sensitization of target cells was completely abrogated under the conditions. Pretreatment of target cells with brefeldin A (BFA), preventing the presentation of endogenous antigens from the class I MHC molecule pathway, did not inhibit the presentation of P18IIIB. Moreover, glutaraldehyde-fixed cells, which can not process native protein, though they could present the exogenously added peptides, were also sensitized by P18IIIB. These results clearly demonstrate that the fine processing to produce I-10 occurred in the extracellular milieu. Furthermore, our result suggests that the longer P18IIIB can bind to the class I molecules on the cell surface, and then be trimmed by ACE while it is bound. The mechanisms behind the extracellular processing outlined in this paper will offer important information for designing peptide-based vaccines to elicit MHC molecule-restricted effectors. [source] Human immunodeficiency virus serotyping on dried serum spots as a screening tool for the surveillance of the AIDS epidemicJOURNAL OF MEDICAL VIROLOGY, Issue S1 2006Francis Barin Abstract Many studies have demonstrated the utility of the dried blood spot (DBS) or dried plasma/serum spot (DSS) method for serological and molecular diagnosis of HIV infection. Here, we report on the description of a serotyping assay performed on DSS, and its application to a national surveillance program of HIV variants. We combined serotyping assays that we developed previously to discriminate between HIV-1 and HIV-2, between HIV-1 group O and HIV-1 group M, and between B and non-B subtypes of HIV-1 group M. The assays are based on antibody binding to either the immunodominant epitope of gp41 or the V3 domain of gp120 of these various types, groups and subtypes. Therefore, a unique enzyme-linked immunosorbent assay (ELISA) format applied to serum eluted from DSS allowed the simultaneous discrimination between infections caused by HIV-1 B, HIV-1 non-B, HIV-1 group O, and HIV-2. Together, this serotyping assay and an immunoassay for recent infection were used for a virological surveillance linked to the anonymous mandatory notification of HIV infection in France. The preliminary results of this virological surveillance allowed us to obtain estimates of the prevalence of the rare variants HIV-2 and HIV-1 group O. It also allowed identification of the two first cases of M/O dual infections reported outside the endemic group O region of the western part of equatorial Africa, and showed that non-B subtypes circulate widely in France, almost 50% of new HIV diagnoses in 2003 being due to these variants. J. Med. Virol. 78:S13,S18, 2006. © 2006 Wiley-Liss, Inc. [source] Peptide based vaccine design: Synthesis and immunological characterization of branched polypeptide conjugates comprising the 276,284 immunodominant epitope of HSV-1 glycoprotein DJOURNAL OF PEPTIDE SCIENCE, Issue 3 2002Gábor Mez Abstract The importance of the length and conjugation site of a protective epitope peptide (276SALLEDPVG284) from glycoprotein D of herpes simplex virus in branched polypeptide conjugates has been investigated. A new set of peptides, with a single attachment site and truncated sequences, was prepared. The immunogenicity of conjugates and the specificity of antibody responses elicited were investigated in BALB/c, C57/Bl/6 and CBA mice. It was found that the covalent coupling of the peptide comprising the 276,284 sequence of gD through its Asp residue at position 281 did not influence the immunogenic properties of the epitope, while involvement of the side chain of Glu at position 280 almost completely abolished immunogenicity. These results clearly indicated that the conjugation site of the epitope peptide influenced the intensity and specificity of antibody responses. Comparison of the immunological properties of conjugates containing truncated gD peptides revealed the presence of two epitopes within the 276,284 region. One of the proposed epitopes is situated at the N -terminal (276,281) region, while the other is located at the C -terminal end of the sequence (279,284). Binding data demonstrated that some of the peptides comprising these epitopes induced gD-specific responses in their conjugated form and also elicited an immune response that conferred protection against lethal HSV-1 infection. The correlation of peptide- and gD-specific antibody responses with the protective effect of the immune response is discussed. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd. [source] In vivo inhibition of antiphospholipid antibody-induced pathogenicity utilizing the antigenic target peptide domain I of ,2 -glycoprotein I: proof of conceptJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2009Y. IOANNOU Summary.,Objectives:,In the antiphospholipid syndrome (APS), the immunodominant epitope for the majority of circulating pathogenic antiphospholipid antibodies (aPLs) is the N-terminal domain I (DI) of ,2 -glycoprotein I. We have previously shown that recombinant DI inhibits the binding of aPLs in fluid phase to immobilized native antigen, and that this inhibition is greater with the DI(D8S/D9G) mutant and absent with the DI(R39S) mutant. Hence, we hypothesized that DI and DI(D8S/D9G) would inhibit aPL-induced pathogenicity in vivo. Methods:,C57BL/6 mice (n = 5, each group) were injected with purified IgG derived from APS patients (IgG-APS, 500 ,g) or IgG from normal healthy serum (IgG-NHS) and either recombinant DI, DI(R39S), DI(D8S/D9G), or an irrelevant control peptide (at 10,40 ,g). Outcome variables measured were femoral vein thrombus dynamics in treated and control groups following standardized vessel injury, expression of vascular cell adhesion molecule-1 (VCAM-1) on the aortic endothelial surface, and tissue factor (TF) activity in murine macrophages. Results:,IgG-APS significantly increased thrombus size as compared with IgG-NHS. The IgG-APS thrombus enhancement effect was abolished in mice pretreated with recombinant DI (P , 0.0001) and DI(D8S/D9G) (P , 0.0001), but not in those treated with DI(R39S) or control peptide. This inhibitory effect by DI was dose-dependent, and at lower doses DI(D8S/D9G) was a more potent inhibitor of thrombosis than wild-type DI (P , 0.01). DI also inhibited IgG-APS induction of VCAM-1 on the aortic endothelial surface and TF production by murine macrophages. Conclusion:,Our findings in this proof-of-concept study support the development of recombinant DI or the novel variant DI(D8S/D9G) as a potential future therapeutic agent for APS. [source] Mapping and characterization of B cell linear epitopes in the conservative regions of hepatitis C virus envelope glycoproteinsJOURNAL OF VIRAL HEPATITIS, Issue 3 2002L. V. Olenina Forty-eight overlapping octapeptides covering highly conservative regions of E1 and E2 hepatitis C virus (HCV) envelope proteins were synthesized and tested by ELISA against different groups of sera obtained from HCV-infected patients. All sera from patients with acute infection, except a single case of serum reactivity with the region HINRTALN, were nonreactive with any peptide. Sera obtained from chronic patients reacted with 12 peptides from five selected regions. Two immunodominant B epitopes were found, one being the precisely mapped antigenic site RMAWDM positioned inside the earlier shown immunodominant epitope from E1, and the second site, PALSTGLIH from E2, detected for the first time. New minor antigenic site was determined as PTDCFRKH from E2. We found only minor seroreactivity for one of the putative sites involved in CD81 binding, PYCWHYAP. [source] Discovery of the hepatitis C virusLIVER INTERNATIONAL, Issue 2009Michael Houghton Abstract After nearly 6 years of intensive investigations between 1982 and 1988 in my laboratory at Chiron corporation, in which numerous molecular biological methods were used to investigate the viral aetiology of parenterally transmitted non-A, non-B viral hepatitis (NANBH), a single cDNA clone (5-1-1) was isolated that was shown to be derived from a new flavi-like virus, termed the hepatitis C virus (HCV). After screening hundreds of millions of bacterial cDNA clones derived from different liver and plasma samples obtained from experimentally infected chimpanzees, a single HCV clone was eventually isolated using a novel, blind immunoscreening method in which antibodies derived from a clinically diagnosed NANBH patient were used to identify a cDNA clone encoding an immunodominant epitope within HCV nonstructural protein 4. Its viral origin was demonstrated by its specific hybridization to a large single-stranded RNA molecule of ,10 000 nucleotides found only in NANBH-infected samples that shared distant sequence identity with flaviviruses. Further, HCV clone 5-1-1 was shown to be extrachromosomal and to encode an antigen eliciting antibody seroconversion only in NANBH-infected chimpanzees and humans. Subsequent work demonstrated that HCV was the principal cause of parenterally transmitted NANBH around the world, with an estimated 170 million global carriers and that blood screening tests detecting circulating HCV antibodies and viral RNA could effectively eradicate the transmission of transfusion-associated NANBH. Key viral-encoded enzymes essential to its life cycle are now the targets of vigorous, ongoing drug development activities, and the feasibility of successful vaccination strategies has been demonstrated using the valuable chimpanzee model, without which any progress on HCV would not have been possible. My colleagues and coworkers who made essential contributions to the discovery of HCV were George Kuo, who had his own laboratory at Chiron and who provided intellectual and practical input, Dan Bradley of the Centers for Disease Control and Prevention, who provided a large supply of well-characterized chimpanzee samples and knowledge of the NANBH field, and Qui-Lim Choo, in my own laboratory, who provided many years of outstandingly dedicated and precise molecular biology expertise. [source] Identification of a gene (lpt-3) required for the addition of phosphoethanolamine to the lipopolysaccharide inner core of Neisseria meningitidis and its role in mediating susceptibility to bactericidal killing and opsonophagocytosisMOLECULAR MICROBIOLOGY, Issue 4 2002Fiona G. Mackinnon Summary We have identified a gene, lpt-3, that is required for the addition of phosphoethanolamine to the 3-position (PEtn-3) on the , -chain heptose (HepII) of the inner core lipopolysaccharide (LPS) of Neisseria meningitidis (Nm). The presence of this PEtn-3 substituent is characteristic of the LPS of a majority (, 70%) of hypervirulent Nm strains, irrespective of capsular serogroup, and is required for the binding of a previously described monoclonal antibody (mAb B5) to a surface-accessible epitope. All strains of Nm that have PEtn-3 possess the lpt-3 gene. In some lpt-3 -containing strains, the 3-position on HepII is preferentially substituted by glucose instead of PEtn, the result of lgtG phase variation mediated by slippage of a homopolymeric tract of cytidines. Inactivation of lpt-3 resulted in loss of PEtn-3, lack of reactivity with mAb B5 and conferred relative resistance to bactericidal killing and opsonophagocytosis by mAb B5 in vitro. Thus, the identification of lpt-3 has facilitated rigorous genetic, structural and immunobiological definition of an immunodominant epitope that is a candidate immunogen for inclusion in an LPS-based vaccine to protect against invasive meningococcal disease. [source] Germline humanization of a murine A, antibody and crystal structure of the humanized recombinant Fab fragmentPROTEIN SCIENCE, Issue 2 2010Remy Robert Abstract Alzheimer's disease is the most common form of dementia, affecting 26 million people worldwide. The A, peptide (39,43 amino acids) derived from the proteolytic cleavage of the amyloid precursor protein is one of the main constituents of amyloid plaques associated with disease pathogenesis and therefore a validated target for therapy. Recently, we characterized antibody fragments (Fab and scFvs) derived from the murine monoclonal antibody WO-2, which bind the immunodominant epitope (3EFRH6) in the A, peptide at the N-terminus. In vitro, these fragments are able to inhibit fibril formation, disaggregate preformed amyloid fibrils, and protect neuroblastoma cells against oligomer-mediated toxicity. In this study, we describe the humanization of WO-2 using complementary determining region loop grafting onto the human germline gene and the determination of the three-dimensional structure by X-ray crystallography. This humanized version retains a high affinity for the A, peptide and therefore is a potential candidate for passive immunotherapy of Alzheimer's disease. [source] The production, purification and crystallization of a soluble heterodimeric form of a highly selected T-cell receptor in its unliganded and liganded stateACTA CRYSTALLOGRAPHICA SECTION D, Issue 12 2002Craig S. Clements T-cell antigen receptors (TcRs) are heterodimeric cell-surface receptors that play a pivotal role in the cellular immune response. The TcR interacts specifically with a peptide-laden major histocompatability complex (pMHC). A human TcR has been characterized that interacts with an immunodominant epitope, FLRGRAYGL, from the Epstein,Barr virus, a ubiquitous human pathogen, in complex with HLA-B8. Despite the vast TcR repertoire, this TcR is found in up to 10% of the total T-cell population in seropositive HLA-B8+ individuals. In this report, this highly selected TcR is characterized by expressing in Escherichia coli, refolding, purifying and crystallizing the receptor. In addition, the HLA-B8,FLRGRAYGL complex has been expressed in E. coli, refolded and shown to be functionally active. Using native gel electrophoresis, the refolded TcR is shown to be capable of binding specifically to the refolded HLA-B8,FLRGRAYGL and this TcR has been crystallized in complex with the pMHC. The crystals of the unliganded and liganded TcR diffract to 1.5 and 2.5,Å, respectively. [source] Antiplectin autoantibodies in subepidermal blistering diseasesBRITISH JOURNAL OF DERMATOLOGY, Issue 4 2009J.J.A. Buijsrogge Summary Background, Hemidesmosomal proteins may become targets of autoimmunity in subepidermal blistering diseases. Well-known recognized autoantigens are the intracellular plaque protein BP230, the transmembrane BP180 and its shed ectodomain LAD-1. Objectives, To establish the prevalence of autoimmunity against plectin, another intracellular plaque protein, and to investigate its antigenic sites. Methods, Two hundred and eighty-two patients with subepidermal blistering diseases, investigated by routine immunoblot analysis for possible antiplectin antibodies, were included in the study. Epitope mapping was performed using recombinantly produced overlapping plectin domains from the actin-binding domain to the rod domain. The COOH-terminal region of plectin was not included in the study. Results, In 11 of 282 (3·9%) patients an immunoblot staining pattern identical to that of antiplectin monoclonal antibody HD121 was found. Affinity-purified antibodies bound back to normal human skin in a pattern typical for plectin, i.e. to the epidermal basement membrane zone as well as to keratinocytes in the epidermis, and to myocytes. No binding was seen to plectin-deficient skin of a patient with epidermolysis bullosa simplex with muscular dystrophy. Epitope mapping of the plectin molecule showed that the central coiled-coil rod domain is an immunodominant hotspot as 92% of the sera with antiplectin antibodies reacted with it. Most patients with antiplectin antibodies also had antibodies to other pemphigoid antigens. Conclusions, Plectin is a minor pemphigoid antigen with an immunodominant epitope located on the central rod domain. [source] Transgenic mice expressing the T cell antigen receptor specific for an immunodominant epitope of a major allergen of house dust mite develop an asthmatic phenotype on exposure of the airways to allergenCLINICAL & EXPERIMENTAL ALLERGY, Issue 7 2005E. R. Jarman Summary Background Current studies on mechanisms underlying allergen-induced pulmonary inflammation and asthma are hampered by the lack of appropriate physiological in vivo models that reflect the natural route of allergen exposure and sensitization. Objective To generate and phenotype a transgenic mouse strain expressing the T cell receptor (TCR) specific for an immunodominant domain of the major inhalant allergen Dermatophagoides pteronyssinus species of house dust mite (Der p 1), for the development of an in vivo model of allergic asthma. Methods Der p 1 transgenic mice were generated using TCR-,, derived from a CD4+ T cell hybridoma reactive with Der p 1 residues p 110,131. The frequency and functional activity of peripheral T cells were determined and parameters of airway inflammation assessed following allergen challenge of the airways with Der p 1. Results CD4+ T cells are functionally active, exhibiting dose-dependent proliferation and IL-4 production on primary stimulation with Der p 1 or Der p 1, p 110,131 in vitro, independent of in vivo antigen priming. On sensitization of the airways with allergen, in the absence of systemic priming or the application of adjuvants, the TCR transgenic mice develop airway inflammation characterized by a marked lymphocytic and eosinophilic infiltrate with goblet cell hyperplasia and enhanced mucin production. Conclusion The Der p 1 TCR transgenic mice provide a model for investigating the pathophysiological mechanisms of pulmonary inflammation following sensitization by exposure of the airways to allergen and for investigating the mode of action and efficacy of novel immunotherapeutics. [source] ADAM-HCV, a new-concept diagnostic assay for antibodies to hepatitis C virus in serumFEBS JOURNAL, Issue 17 2001Olga Minenkova We screened phage libraries using sera from noninfected individuals and patients infected by hepatitis C virus (HCV). By applying different selection and maturation strategies, we identified a wide collection of efficient phage-borne ligands for HCV-specific antibodies. The selected ligands retained their antigenic properties when expressed as multimeric synthetic peptides. Peptides that mimic several immunodominant epitopes of the virus were used to develop a novel type of diagnostic assay which efficiently detects antibodies to HCV in serum. This type of analysis provides a conclusive diagnosis for many patients identified as indeterminate according to presently available serological assays. [source] Epstein-Barr virus infection and risk of lymphoma: Immunoblot analysis of antibody responses against EBV-related proteins in a large series of lymphoma subjects and matched controlsINTERNATIONAL JOURNAL OF CANCER, Issue 8 2007Silvia de Sanjosé Abstract Epstein-Barr Virus (EBV) is consistently associated with distinct lymphoproliferative malignancies and aberrant EBV antibody patterns are found in most EBV cancer patients. We evaluate the detection of an abnormal reactive serological pattern to EBV (ab_EBV) infection and the risk of lymphoma in a multicentric case,control study. Serum samples were collected at study entry from 1,085 incident lymphoma cases from Spain, France, Germany, Czech Republic, Italy and 1,153 age, sex and country matched controls. EBV immunoglobulin G (IgG) serostatus was evaluated through a peptide-based ELISA combining immunodominant epitopes of EBNA1 (BKRF1) and VCA-p18 (BFRF3). Further, immunoblot analysis was performed to evaluate distinct antibody diversity patterns to EBV early antigens (EA), besides EBNA1, VCA-p18, VCA-p40 (BdRF1) and Zebra (BZLF1). Patients with chronic active EBV infection and aberrant EBV activity were characterized as having an abnormal reactive pattern (ab_EBV). Ab_EBV was observed in 20.9% of 2,238 included subjects with an increased proportion of cases presenting ab_EBV as compared to the control population (23.9% vs. 18.0% p = 0.001). Ab_EBV positivity was a risk factor for all lymphomas combined (odds ratio [OR] = 1.42, 95% confidence interval [CI]=1.15,1.74), and specifically for chronic lymphocytic leukaemia (OR = 2.96, 95%CI = 2.22,3.95). Lower levels of ab_EBV were observed for follicular lymphoma (OR = 0.38, 95%CI = 0.15,0.98). EBV may be involved in a larger subset of lymphomas among clinically immunocompetent subjects than previously thought, probably explained by an underlying loss of immune control of EBV latent infection. Ab_EBV is a useful tool to explore EBV imbalances preceeding or paralleling possible EBV associated oncogenic events. © 2007 Wiley-Liss, Inc. [source] Antigenic properties of the GroEL-like protein of Campylobacter rectusMOLECULAR ORAL MICROBIOLOGY, Issue 1 2002D. Hinode The purpose of this study was to clarify the antigenic properties of the GroEL-like protein of Campylobacter rectus using a specific polyclonal antibody directed to the purified 64-kDa GroEL-like protein (pAb- CrGroEL), a polyclonal antibody directed to the Actinobacillus actinomycetemcomitans GroEL-like protein (pAb- AaGroEL) and a monoclonal antibody against the recombinant human HSP60 (mAb-HuHSP60). In SDS-PAGE/Western immunoblotting analysis, mAb-HuHSP60, pAb- CrGroEL and pAb- AaGroEL were found to react with the GroEL-like protein (64-kDa) present in all C. rectus strains. A 150-kDa protein in C. rectus ATCC 33238 also reacted strongly with pAb- CrGroEL. This 150-kDa protein was found to be present on the surface-associated material of bacterial cells, as determined by transmission electron microscopy and immunogold labelling of cells with pAb- CrGroEL. Analysis of the first 20 N -terminal amino acids of the sequence of the 150-kDa protein revealed a strong homology (80%) with the C. rectus surface layer (S-layer) protein. Investigation of the biochemical nature of antigenic determinants using periodic acid and proteolytic enzymes showed that the C. rectus GroEL-like protein possessed immunodominant epitopes in both peptide and carbohydrate chains, and that the immunoreactive determinants of the 150-kDa protein belonged to carbohydrate. These results suggest that the GroEL-like protein and the S-layer protein of C. rectus may share the same carbohydrate epitopes. [source] | ||||||||||||||||