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Sample records for surface antigen r-hbsag

  1. Monoclonal antibodies against rat leukocyte surface antigens

    NARCIS (Netherlands)

    van den Berg, T. K.; Puklavec, M. J.; Barclay, A. N.; Dijkstra, C. D.

    2001-01-01

    Monoclonal antibodies have proven to be powerful tools for studying the properties of leukocyte surface antigens and the cells that express them. In the past decades many monoclonal antibodies (mAb) for identifying the different rat leukocyte surface antigens have been described. A list of mAb is

  2. Analysis of cell surface antigens by Surface Plasmon Resonance imaging

    NARCIS (Netherlands)

    Stojanovic, Ivan; Schasfoort, Richardus B.M.; Terstappen, Leonardus Wendelinus Mathias Marie

    2013-01-01

    Surface Plasmon Resonance (SPR) is most commonly used to measure bio-molecular interactions. SPR is used significantly less frequent for measuring whole cell interactions. Here we introduce a method to measure whole cells label free using the specific binding of cell surface antigens expressed on

  3. 21 CFR 660.40 - Hepatitis B Surface Antigen.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Hepatitis B Surface Antigen. 660.40 Section 660.40...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Hepatitis B Surface Antigen § 660.40 Hepatitis B Surface Antigen. (a) Proper name and definition. The proper name of this product...

  4. Identification of Surface Exposed Elementary Body Antigens of ...

    African Journals Online (AJOL)

    This study sought to identify the surface exposed antigenic components of Cowdria ruminantium elementary body (EB) by biotin labeling, determine effect of reducing and non-reducing conditions and heat on the mobility of these antigens and their reactivity to antibodies from immunized animals by Western blotting.

  5. Seroprevalence of hepatitis B surface antigen among pregnant ...

    African Journals Online (AJOL)

    Seroprevalence of hepatitis B surface antigen among pregnant women attending the Hospital for Women & Children in Koutiala, Mali. Brett MacLean, Rosanna F Hess, Edward Bonvillain, Joseph Kamate, Daoda Dao, Amy Cosimano, Shannon Hoy ...

  6. 21 CFR 660.1 - Antibody to Hepatitis B Surface Antigen.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Antibody to Hepatitis B Surface Antigen. 660.1... Hepatitis B Surface Antigen § 660.1 Antibody to Hepatitis B Surface Antigen. (a) Proper name and definition. The proper name of this product shall be Antibody to Hepatitis B Surface Antigen. The product is...

  7. Prevalence of Hepatitis B Surface Antigen among Women of ...

    African Journals Online (AJOL)

    This study documents the seroprevalence of hepatitis B surface antigen (HBs Ag) among women of childbearing age attending various family clinics in Lagos, Nigeria. A total of 501 women were screened with Wellcozyme ELISA technique, of which 45(8.9%) were seropositive. Women in occupations related to needle work ...

  8. Monoclonal Antibody Production against Human Spermatozoal Surface Antigens

    Directory of Open Access Journals (Sweden)

    M Jedi-Tehrani

    2005-10-01

    Full Text Available Introduction: As monoclonal antibodies are potential tools for characterization of soluble or cellular surface antigens, use of these proteins has always been considered in infertility and reproduction research. Therefore, in this study, monoclonal antibodies against human sperm surface antigens were produced. Material and Methods: To produce specific clones against human sperm surface antigens, proteins were extracted using solubilization methods. Balb/c mice were immunized intraperitoneally with the proteins using complete Freund’s adjuvant in the first injection and incomplete Adjuvant in the following booster injections. Hybridoma cells producing ASA were cloned by limiting dilution. Results: Five stable ASA producing hybridoma clones were achieved and their antibody isotypes were determined by ELISA. All the isotypes were of IgG class. Their cross reactivity with rat and mice spermatozoa was examined but they did not have any cross reactivity. Conclusion: The produced antibodies can be used in further studies to characterize and evaluate each of the antigens present on human sperm surface and determining their role in fertilization.

  9. Prevalence of hepatitis B surface antigen seropositivity among HIV ...

    African Journals Online (AJOL)

    Hepatitis B surface antigen (HBsAg) was tested for using a one step lateral flow rapid chromatographic immunoassay (Acumen labs and diagnostic centre, Bangalore, India) and HIV 1/2 was tested using two kits, Determine (made by Abbot, Japan for Inverness Medical, Japan). Results: A total of 2018 subjects were studied ...

  10. Prevalence of hepatitis b virus surface antigens (HBsag) and ...

    African Journals Online (AJOL)

    The prevalences of hepatitis B virus surface antigen (HBsAg) and hepatitis C virus (HCV) antibodies were determined in 560 blood donors sera using ELISA kits (DIALAB., Austria). Forty eight (8.57%) of these were positive for hepatitis B virus infection, while 33(5.89%) were positive to hepatitis C virus antibodies. The sex ...

  11. Hepatitis B surface antigen incorporated in dissolvable microneedle array patch is antigenic and thermostable.

    Science.gov (United States)

    Poirier, Danielle; Renaud, Frédéric; Dewar, Vincent; Strodiot, Laurent; Wauters, Florence; Janimak, Jim; Shimada, Toshio; Nomura, Tatsuya; Kabata, Koki; Kuruma, Koji; Kusano, Takayuki; Sakai, Masaki; Nagasaki, Hideo; Oyamada, Takayoshi

    2017-11-01

    Alternatives to syringe-based administration are considered for vaccines. Intradermal vaccination with dissolvable microneedle arrays (MNA) appears promising in this respect, as an easy-to-use and painless method. In this work, we have developed an MNA patch (MNAP) made of hydroxyethyl starch (HES) and chondroitin sulphate (CS). In swines, hepatitis B surface antigen (HBsAg) formulated with the saponin QS-21 as adjuvant, both incorporated in HES-based MNAP, demonstrated the same level of immunogenicity as a commercially available aluminum-adjuvanted HBsAg vaccine, after two immunizations 28 days apart. MNAP application was associated with transient skin reactions (erythema, lump, scab), particularly evident when the antigen was delivered with the adjuvant. The thermostability of the adjuvanted antigen when incorporated in the HES-based matrix was also assessed by storing MNAP at 37, 45 or 50 °C for up to 6 months. We could demonstrate that antigenicity was retained at 37 and 45 °C and only a 10% loss was observed after 6 months at 50 °C. Our results are supportive of MNAP as an attractive alternative to classical syringe-based vaccination. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Paired Expression Analysis of Tumor Cell Surface Antigens

    Directory of Open Access Journals (Sweden)

    Rimas J. Orentas

    2017-08-01

    Full Text Available Adoptive immunotherapy with antibody-based therapy or with T cells transduced to express chimeric antigen receptors (CARs is useful to the extent that the cell surface membrane protein being targeted is not expressed on normal tissues. The most successful CAR-based (anti-CD19 or antibody-based therapy (anti-CD20 in hematologic malignancies has the side effect of eliminating the normal B cell compartment. Targeting solid tumors may not provide a similar expendable marker. Beyond antibody to Her2/NEU and EGFR, very few antibody-based and no CAR-based therapies have seen broad clinical application for solid tumors. To expand the way in which the surfaceome of solid tumors can be analyzed, we created an algorithm that defines the pairwise relative overexpression of surface antigens. This enables the development of specific immunotherapies that require the expression of two discrete antigens on the surface of the tumor target. This dyad analysis was facilitated by employing the Hotelling’s T-squared test (Hotelling–Lawley multivariate analysis of variance for two independent variables in comparison to a third constant entity (i.e., gene expression levels in normal tissues. We also present a unique consensus scoring mechanism for identifying transcripts that encode cell surface proteins. The unique application of our bioinformatics processing pipeline and statistical tools allowed us to compare the expression of two membrane protein targets as a pair, and to propose a new strategy based on implementing immunotherapies that require both antigens to be expressed on the tumor cell surface to trigger therapeutic effector mechanisms. Specifically, we found that, for MYCN amplified neuroblastoma, pairwise expression of ACVR2B or anaplastic lymphoma kinase (ALK with GFRA3, GFRA2, Cadherin 24, or with one another provided the strongest hits. For MYCN, non-amplified stage 4 neuroblastoma, neurotrophic tyrosine kinase 1, or ALK paired with GFRA2, GFRA3, SSK

  13. Genetic variation and significance of hepatitis B surface antigen

    Directory of Open Access Journals (Sweden)

    ZHANG Zhenhua

    2013-11-01

    Full Text Available Hepatitis B virus (HBV is prone to genetic variation because there is reverse transcription in the process of HBV replication. The gene mutation of hepatitis B surface antigen may affect clinical diagnosis of HBV infection, viral replication, and vaccine effect. The current research and existing problems are discussed from the following aspects: the mechanism and biological and clinical significance of S gene mutation. Most previous studies focused on S gene alone, so S gene should be considered as part of HBV DNA in the future research on S gene mutation.

  14. Stable isotope labeling of oligosaccharide cell surface antigens

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Silks, L.A. III; Martinez, R.A. [and others

    1998-12-31

    The overall goal of this Laboratory Directed Research and Development (LDRD) project was to develop new methods for synthesis of {sup 13}C-labeled oligosaccharides that are required for nuclear magnetic resonance (NMR) studies of their solution conformation. Oligosaccharides are components of the cell`s outer surface and are involved in important processes such as cell-cell recognition and adhesion. Recently, Danishefsky and coworkers at Slone-Kettering Cancer Center developed a method for the solid-phase chemical synthesis of oligosaccharides. The specific goal of this LDRD project was to prepare uniform {sup 13}C-labeled aldohexose precursors required for the solid-phase synthesis of the Lewis blood-group antigenic determinants. We report the synthesis of {sup 13}C-labeled D-glucal, D-galactal and Fucosyl precursors. We have been collaborating with the Danishefsky group on the synthesis of the Lewis oligosaccharides and the NMR analysis of their solution conformation.

  15. Detection of Carcinoembryonic Antigens Using a Surface Plasmon Resonance Biosensor

    Science.gov (United States)

    Su, Fengyu; Xu, Chunye; Taya, Minoru; Murayama, Kimie; Shinohara, Yasuro; Nishimura, Shin-Ichiro

    2008-01-01

    Carcinoembryonic antigen (CEA) is an oncofoetal cell-surface glycoprotein that serves as an important tumor marker for colorectal and some other carcinomas. In this work, a CEA immunoassay using a surface plasmon resonance (SPR) biosensor has been developed. SPR could provide label-free, real-time detection with high sensitivity, though its ability to detect CEA in human serum was highly dependent on the analytical conditions employed. We investigated the influences of various analytical conditions including immobilization methods for anti-CEA antibody and composition of sensor surface on the selective and sensitive detection of CEA. The results show that anti-CEA antibody immobilized via Protein A or Protein G caused a large increase in the resonance signal upon injection of human serum due to the interactions with IgGs in serum, while direct covalent immobilization of anti-CEA antibody could substantially reduce it. An optimized protocol based on further kinetic analysis and the use of 2nd and 3rd antibodies for the sandwich assay allowed detecting spiked CEA in human serum as low as 25 ng/mL. Furthermore, a self-assembled monolayer of mixed ethylene-glycol terminated alkanethiols on gold was found to have a comparable ability in detecting CEA as CM5 with thick dextran matrix and C1 with short flat layer on gold. PMID:27879935

  16. Effect of hepatitis B immunisation in newborn infants of mothers positive for hepatitis B surface antigen

    DEFF Research Database (Denmark)

    Lee, Chuanfang; Gong, Yan; Brok, Jesper

    2006-01-01

    To evaluate the effects of hepatitis B vaccine and immunoglobulin in newborn infants of mothers positive for hepatitis B surface antigen.......To evaluate the effects of hepatitis B vaccine and immunoglobulin in newborn infants of mothers positive for hepatitis B surface antigen....

  17. Hepatitis B Virus DNA in Blood Samples Positive for Antibodies to Core Antigen and Negative for Surface Antigen

    Science.gov (United States)

    Gutiérrez, C.; León, G.; Loureiro, C. L.; Uzcátegui, N.; Liprandi, F.; Pujol, F. H.

    1999-01-01

    Anti-hepatitis B core antigen (HBcAg)-positive hepatitis B surface antigen (HBsAg)-negative plasma samples from blood donors were tested by nested PCR. DNA positivity was more significantly associated with high levels of anti-HBcAg than with low levels of anti-HBsAg antibodies. Analysis of a dilution of anti-HBcAg antibodies might result in a more rational exclusion of anti-HBcAg-positive HBsAg-negative samples, reducing the number of donations discarded and enabling more countries to incorporate anti-HBcAg testing. PMID:10473534

  18. Artificial neural network accurately predicts hepatitis B surface antigen seroclearance.

    Directory of Open Access Journals (Sweden)

    Ming-Hua Zheng

    Full Text Available BACKGROUND & AIMS: Hepatitis B surface antigen (HBsAg seroclearance and seroconversion are regarded as favorable outcomes of chronic hepatitis B (CHB. This study aimed to develop artificial neural networks (ANNs that could accurately predict HBsAg seroclearance or seroconversion on the basis of available serum variables. METHODS: Data from 203 untreated, HBeAg-negative CHB patients with spontaneous HBsAg seroclearance (63 with HBsAg seroconversion, and 203 age- and sex-matched HBeAg-negative controls were analyzed. ANNs and logistic regression models (LRMs were built and tested according to HBsAg seroclearance and seroconversion. Predictive accuracy was assessed with area under the receiver operating characteristic curve (AUROC. RESULTS: Serum quantitative HBsAg (qHBsAg and HBV DNA levels, qHBsAg and HBV DNA reduction were related to HBsAg seroclearance (P<0.001 and were used for ANN/LRM-HBsAg seroclearance building, whereas, qHBsAg reduction was not associated with ANN-HBsAg seroconversion (P = 0.197 and LRM-HBsAg seroconversion was solely based on qHBsAg (P = 0.01. For HBsAg seroclearance, AUROCs of ANN were 0.96, 0.93 and 0.95 for the training, testing and genotype B subgroups respectively. They were significantly higher than those of LRM, qHBsAg and HBV DNA (all P<0.05. Although the performance of ANN-HBsAg seroconversion (AUROC 0.757 was inferior to that for HBsAg seroclearance, it tended to be better than those of LRM, qHBsAg and HBV DNA. CONCLUSIONS: ANN identifies spontaneous HBsAg seroclearance in HBeAg-negative CHB patients with better accuracy, on the basis of easily available serum data. More useful predictors for HBsAg seroconversion are still needed to be explored in the future.

  19. Simultaneous detection of Hepatitis B surface antigen and its antibody by radioimmunoassay

    International Nuclear Information System (INIS)

    Crouzat-Reynes, Gerard; Perigois, Francois; Lecureuil, Michel; Lejeune, Bernard

    1981-01-01

    The authors describe an original radioimmunoassay which allows the simultaneous detection of hepatitis B surface antigen and its antibody in a biological sample. Antigen and antibody are indiscriminately detected in a first step and then distinguished in a second step using the same reagents [fr

  20. Identification and characterization of surface antigens in parasites, using radiolabelling techniques

    International Nuclear Information System (INIS)

    Ramasamy, R.

    1982-04-01

    Surface proteins of Schistosoma sp and Leishmania sp were studied using 125-Iodine as tracer. The surface proteins were labelled by the Lactoperoxidase method and the proteins then separated using SDS PAG electrophoresis and autoradiography. The possible immunogens were then separated using immunoprecipitation and Fluorescent Antibody techniques using sera from patients or from artificially immunized rabbits. Four common antigens were identified from the surfaces of male and female adult worms, cercariae and schistosomulae of S.mansoni. These antigens, which had molecular weights of 150,000, 78,000, 45,000, and 22,000 were also isolated from the surfaces of S.haematobium adults. The surface antigens on promastigotes of a Kenyan strain of Leishmania donovani were separated into three protein antigens with molecular weights of 66,000, 59,000 and 43,000 respectively. The 59,000 molecular weight antigen was a glycoprotein and was common to promastigotes of an American and Indian strain of L.donovani and to L.braziliensis mexicana. None of the isolated antigens have been shown to have a protective effect when vaccinated into mice, but the study illustrates the value of radionuclide tracers in the unravelling of the mosaic of antigens which parasites possess

  1. Sero-prevalence of hepatitis B surface antigen among pregnant ...

    African Journals Online (AJOL)

    There were no significant differences between prevalence recorded and agegroups but these were significant associations between risk factors namely tribal marks/tattooing, types of marriages and prevalence of hepatitis infection. The prevalence of hepatitis B antigen among pregnant women suggests that vertical ...

  2. Immunochemical Investigations of Cell Surface Antigens of Anaerobic Bacteria.

    Science.gov (United States)

    1976-01-15

    has also been visulalized . With use of a radioactive anti’qen bindinq assay, antibody to this capsularpolysaccharide has been demonstrated in anti- sera...With many bacteria, serogrouning is based on cansular oolysaccharide antigens. Serogrouping has led to much valuable epidemiologic information

  3. Preservation of surface-dependent properties of viral antigens following immobilization on particulate ceramic delivery vehicles.

    Science.gov (United States)

    Kossovsky, N; Gelman, A; Sponsler, E; Rajguru, S; Torres, M; Mena, E; Ly, K; Festekjian, A

    1995-05-01

    B-cell stimulation for the purpose of evoking an effective neutralizing humoral immune response is a surface phenomenon that is exquisitely specific to antigen conformation. Consequently, successful delivery of antigen, such as would be desired in a vaccine, entails preservation of an antigen's apparent native surface (conformational) properties. Prior to testing the actual vaccinating efficacy of delivered antigens, the surface properties could be assessed through a variety of in vitro and in vivo assays in which the measurement standard would be the properties of the antigens in their native state (whole virus). Using surface modified nanocrystalline carbon and calcium-phosphate ceramic particulates (carbon ceramics and brushite), we evaluated the surface activity of immobilized non-nuclear material extracted from HIV-1. Physical characterization showed that the particles with immobilized antigen ("HIV decoys") measured 50 nm in diameter (HIV = 50-100 nm) and exhibited the same zeta potentials as whole (live) HIV. In vitro testing showed that the HIV decoys were recognized by both conformationally nonspecific and specific monoclonal antibodies, were recognized by human IgG from HIV antibody-positive patients, and could promote surface agglomeration among malignant T-cells similar to live HIV. Last, in vivo testing in three vaccinated animal species showed that the HIV decoys elicited humoral and cellular immune responses similar to that evoked by whole (live) HIV.

  4. CARbodies: Human Antibodies Against Cell Surface Tumor Antigens Selected From Repertoires Displayed on T Cell Chimeric Antigen Receptors

    Directory of Open Access Journals (Sweden)

    Vanesa Alonso-Camino

    2013-01-01

    Full Text Available A human single-chain variable fragment (scFv antibody library was expressed on the surface of human T cells after transduction with lentiviral vectors (LVs. The repertoire was fused to a first-generation T cell receptor ζ (TCRζ-based chimeric antigen receptor (CAR. We used this library to isolate antibodies termed CARbodies that recognize antigens expressed on the tumor cell surface in a proof-of-principle system. After three rounds of activation-selection there was a clear repertoire restriction, with the emergence dominant clones. The CARbodies were purified from bacterial cultures as soluble and active proteins. Furthermore, to validate its potential application for adoptive cell therapy, human T cells were transduced with a LV encoding a second-generation costimulatory CAR (CARv2 bearing the selected CARbodies. Transduced human primary T cells expressed significant levels of the CARbodies-based CARv2 fusion protein on the cell surface, and importantly could be specifically activated, after stimulation with tumor cells. This approach is a promising tool for the generation of antibodies fully adapted to the display format (CAR and the selection context (cell synapse, which could extend the scope of current adoptive cell therapy strategies with CAR-redirected T cells.

  5. Relation between laboratory test results and histological hepatitis activity in individuals positive for hepatitis B surface antigen and antibodies to hepatitis B e antigen

    NARCIS (Netherlands)

    ter Borg, F.; ten Kate, F. J.; Cuypers, H. T.; Leentvaar-Kuijpers, A.; Oosting, J.; Wertheim-van Dillen, P. M.; Honkoop, P.; Rasch, M. C.; de Man, R. A.; van Hattum, J.; Chamuleau, R. A.; Reesink, H. W.; Jones, E. A.

    1998-01-01

    BACKGROUND: Hepatitis B surface antigen (HBsAg) and antibodies to hepatitis B e antigen (anti-HBe) commonly coexist, and laboratory tests are often requested to assess histological hepatitis activity. An optimum panel of tests has not been found and the usefulness of hepatitis B virus (HBV) DNA

  6. Human peripheral blood monocytes display surface antigens recognized by monoclonal antinuclear antibodies

    International Nuclear Information System (INIS)

    Holers, V.M.; Kotzin, B.L.

    1985-01-01

    The authors used monoclonal anti-nuclear autoantibodies and indirect immunofluorescence to examine normal human peripheral blood mononuclear leukocytes for the presence of cell surface nuclear antigens. Only one monoclonal anti-histone antibody (MH-2) was found to bind to freshly isolated PBL, staining approximately 10% of large cells. However, after cells were placed into culture for 16-24 h, a high percentage (up to 60%) of large-sized cells were recognized by an anti-DNA (BWD-1) and several different antihistone monoclonal antibodies (BWH-1, MH-1, and MH-2). These antibodies recognize separate antigenic determinants on chromatin and histones extracted from chromatin. The histone antigen-positive cells were viable, and the monoclonal antibodies could be shown to be binding to the cell surface and not to the nucleus. Using monoclonal antibodies specific for monocytes and T cells, and complement-mediated cytotoxicity, the cells bearing histone antigens were shown to be primarily monocytes. The appearance of histone and DNA antigen-positive cells was nearly completely inhibited by the addition of low concentrations of cycloheximide at initiation of the cultures. In contrast, little effect on the percentage of positive cells was detected if cells were exposed to high doses of gamma irradiation before culture. These data further support the existence of cell surface nuclear antigens on selected cell subsets, which may provide insight into the immunopathogenesis of systemic lupus erythematosus and related autoimmune diseases

  7. The role of Plasmodium falciparum variant surface antigens in protective immunity and vaccine development

    DEFF Research Database (Denmark)

    Hviid, Lars

    2010-01-01

    There is substantial immuno-epidemiological evidence that the parasite-encoded, so-called variant surface antigens (VSAs) such as PfEMP1 on the surface of infected erythrocytes (IEs) are important-in some cases probably decisive-determinants of clinical outcome of P. falciparum malaria. The evide...

  8. Surface plasmon resonance is an analytically sensitive method for antigen profiling of extracellular vesicles

    NARCIS (Netherlands)

    Gool, Elmar L.; Stojanovic, Ivan; Schasfoort, Richardus B.M.; Sturk, Auguste; Van Leeuwen, Ton G.; Nieuwland, Rienk; Terstappen, Leon W.M.M.; Coumans, Frank A.W.

    2017-01-01

    BACKGROUND: Identification, enumeration, and characterization of extracellular vesicles (EVs) are hampered by the small size of EVs, a low refractive index, and low numbers of antigens on their surface. METHODS: We investigated the potential of a 48- multiplex surface plasmon resonance imaging

  9. Surface Plasmon Resonance is an Analytically Sensitive Method for Antigen Profiling of Extracellular Vesicles

    NARCIS (Netherlands)

    Gool, Elmar L.; Stojanovic, Ivan; Schasfoort, Richard B. M.; Sturk, Auguste; van Leeuwen, Ton G.; Nieuwland, Rienk; Terstappen, Leon W. M. M.; Coumans, Frank A. W.

    2017-01-01

    Identification, enumeration, and characterization of extracellular vesicles (EVs) are hampered by the small size of EVs, a low refractive index, and low numbers of antigens on their surface. We investigated the potential of a 48-multiplex surface plasmon resonance imaging (SPRi) system to perform EV

  10. The Effect of Superparamagnetic Iron Oxide Nanoparticle Surface Charge on Antigen Cross-Presentation.

    Science.gov (United States)

    Mou, Yongbin; Xing, Yun; Ren, Hongyan; Cui, Zhihua; Zhang, Yu; Yu, Guangjie; Urba, Walter J; Hu, Qingang; Hu, Hongming

    2017-12-01

    Magnetic nanoparticles (NPs) of superparamagnetic iron oxide (SPIO) have been explored for different kinds of applications in biomedicine, mechanics, and information. Here, we explored the synthetic SPIO NPs as an adjuvant on antigen cross-presentation ability by enhancing the intracellular delivery of antigens into antigen presenting cells (APCs). Particles with different chemical modifications and surface charges were used to study the mechanism of action of antigen delivery. Specifically, two types of magnetic NPs, γFe 2 O 3 /APTS (3-aminopropyltrimethoxysilane) NPs and γFe 2 O 3 /DMSA (meso-2, 3-Dimercaptosuccinic acid) NPs, with the same crystal structure, magnetic properties, and size distribution were prepared. Then, the promotion of T-cell activation via dendritic cells (DCs) was compared among different charged antigen coated NPs. Moreover, the activation of the autophagy, cytosolic delivery of the antigens, and antigen degradation mediated by the proteasome and lysosome were measured. Our results indicated that positive charged γFe 2 O 3 /APTS NPs, but not negative charged γFe 2 O 3 /DMSA NPs, enhanced the cross-presentation ability of DCs. Increased cross-presentation ability induced by γFe 2 O 3 /APTS NPs was associated with increased cytosolic antigen delivery. On the contrary, γFe 2 O 3 /DMSA NPs was associated with rapid autophagy. Overall, our results suggest that antigen delivered in cytoplasm induced by positive charged particles is beneficial for antigen cross-presentation and T-cell activation. NPs modified with different chemistries exhibit diverse biological properties and differ greatly in their adjuvant potentials. Thus, it should be carefully considered many different effects of NPs to design effective and safe adjuvants.

  11. Mendelian and non-mendelian mutations affecting surface antigen expression in Paramecium tetraurelia

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, L.M.; Forney, J.D.

    1984-08-01

    A screening procedure was devised for the isolation of X-ray-induced mutations affecting the expression of the A immobilization antigen (i-antigen) in Paramecium tetraurelia. Two of the mutations isolated by this procedure proved to be in modifier genes. The two genes are unlinked to each other and unlinked to the structural A i-antigen gene. These are the first modifier genes identified in a Paramecium sp. that affect surface antigen expression. Another mutation was found to be a deletion of sequences just downstream from the A i-antigen gene. In cells carrying this mutation, the A i-antigen gene lies in close proximity to the end of a macronuclear chromosome. The expression of the A i-antigen is not affected in these cells, demonstrating that downstream sequences are not important for the regulation and expression of the A i-antigen gene. A stable cell line was also recovered which shows non-Mendelian inheritance of a macronuclear deletion of the A i-antigen gene. This mutant does not contain the gene in its macronucleus, but contains a complete copy of the gene in its micronucleus. In the cytoplasm of wild-type animals, the micronuclear gene is included in the developing macronucleus; in the cytoplasm of the mutant, the incorporation of the A i-antigen gene into the macronucleus is inhibited. This is the first evidence that a mechanism is available in ciliates to control the expression of a gene by regulating its incorporation into developing macronuclei.

  12. Mendelian and non-mendelian mutations affecting surface antigen expression in Paramecium tetraurelia

    International Nuclear Information System (INIS)

    Epstein, L.M.; Forney, J.D.

    1984-01-01

    A screening procedure was devised for the isolation of X-ray-induced mutations affecting the expression of the A immobilization antigen (i-antigen) in Paramecium tetraurelia. Two of the mutations isolated by this procedure proved to be in modifier genes. The two genes are unlinked to each other and unlinked to the structural A i-antigen gene. These are the first modifier genes identified in a Paramecium sp. that affect surface antigen expression. Another mutation was found to be a deletion of sequences just downstream from the A i-antigen gene. In cells carrying this mutation, the A i-antigen gene lies in close proximity to the end of a macronuclear chromosome. The expression of the A i-antigen is not affected in these cells, demonstrating that downstream sequences are not important for the regulation and expression of the A i-antigen gene. A stable cell line was also recovered which shows non-Mendelian inheritance of a macronuclear deletion of the A i-antigen gene. This mutant does not contain the gene in its macronucleus, but contains a complete copy of the gene in its micronucleus. In the cytoplasm of wild-type animals, the micronuclear gene is included in the developing macronucleus; in the cytoplasm of the mutant, the incorporation of the A i-antigen gene into the macronucleus is inhibited. This is the first evidence that a mechanism is available in ciliates to control the expression of a gene by regulating its incorporation into developing macronuclei

  13. The Effect of Superparamagnetic Iron Oxide Nanoparticle Surface Charge on Antigen Cross-Presentation

    Science.gov (United States)

    Mou, Yongbin; Xing, Yun; Ren, Hongyan; Cui, Zhihua; Zhang, Yu; Yu, Guangjie; Urba, Walter J.; Hu, Qingang; Hu, Hongming

    2017-01-01

    Magnetic nanoparticles (NPs) of superparamagnetic iron oxide (SPIO) have been explored for different kinds of applications in biomedicine, mechanics, and information. Here, we explored the synthetic SPIO NPs as an adjuvant on antigen cross-presentation ability by enhancing the intracellular delivery of antigens into antigen presenting cells (APCs). Particles with different chemical modifications and surface charges were used to study the mechanism of action of antigen delivery. Specifically, two types of magnetic NPs, γFe2O3/APTS (3-aminopropyltrimethoxysilane) NPs and γFe2O3/DMSA (meso-2, 3-Dimercaptosuccinic acid) NPs, with the same crystal structure, magnetic properties, and size distribution were prepared. Then, the promotion of T-cell activation via dendritic cells (DCs) was compared among different charged antigen coated NPs. Moreover, the activation of the autophagy, cytosolic delivery of the antigens, and antigen degradation mediated by the proteasome and lysosome were measured. Our results indicated that positive charged γFe2O3/APTS NPs, but not negative charged γFe2O3/DMSA NPs, enhanced the cross-presentation ability of DCs. Increased cross-presentation ability induced by γFe2O3/APTS NPs was associated with increased cytosolic antigen delivery. On the contrary, γFe2O3/DMSA NPs was associated with rapid autophagy. Overall, our results suggest that antigen delivered in cytoplasm induced by positive charged particles is beneficial for antigen cross-presentation and T-cell activation. NPs modified with different chemistries exhibit diverse biological properties and differ greatly in their adjuvant potentials. Thus, it should be carefully considered many different effects of NPs to design effective and safe adjuvants.

  14. Surface proteome analysis and characterization of surface cell antigen (Sca or autotransporter family of Rickettsia typhi.

    Directory of Open Access Journals (Sweden)

    Khandra T Sears

    Full Text Available Surface proteins of the obligate intracellular bacterium Rickettsia typhi, the agent of murine or endemic typhus fever, comprise an important interface for host-pathogen interactions including adherence, invasion and survival in the host cytoplasm. In this report, we present analyses of the surface exposed proteins of R. typhi based on a suite of predictive algorithms complemented by experimental surface-labeling with thiol-cleavable sulfo-NHS-SS-biotin and identification of labeled peptides by LC MS/MS. Further, we focus on proteins belonging to the surface cell antigen (Sca autotransporter (AT family which are known to be involved in rickettsial infection of mammalian cells. Each species of Rickettsia has a different complement of sca genes in various states; R. typhi, has genes sca1 thru sca5. In silico analyses indicate divergence of the Sca paralogs across the four Rickettsia groups and concur with previous evidence of positive selection. Transcripts for each sca were detected during infection of L929 cells and four of the five Sca proteins were detected in the surface proteome analysis. We observed that each R. typhi Sca protein is expressed during in vitro infections and selected Sca proteins were expressed during in vivo infections. Using biotin-affinity pull down assays, negative staining electron microscopy, and flow cytometry, we demonstrate that the Sca proteins in R. typhi are localized to the surface of the bacteria. All Scas were detected during infection of L929 cells by immunogold electron microscopy. Immunofluorescence assays demonstrate that Scas 1-3 and 5 are expressed in the spleens of infected Sprague-Dawley rats and Scas 3, 4 and 5 are expressed in cat fleas (Ctenocephalides felis. Sca proteins may be crucial in the recognition and invasion of different host cell types. In short, continuous expression of all Scas may ensure that rickettsiae are primed i to infect mammalian cells should the flea bite a host, ii to remain

  15. Determinants of spontaneous surface antigen loss in hepatitis B e antigen-negative patients with a low viral load.

    Science.gov (United States)

    Tseng, Tai-Chung; Liu, Chun-Jen; Yang, Hung-Chih; Su, Tung-Hung; Wang, Chia-Chi; Chen, Chi-Ling; Kuo, Stephanie Fang-Tzu; Liu, Chen-Hua; Chen, Pei-Jer; Chen, Ding-Shinn; Kao, Jia-Horng

    2012-01-01

    Loss of hepatitis B surface antigen (HBsAg) usually indicates the cure of hepatitis B virus (HBV) infection. In spontaneous hepatitis B e antigen (HBeAg) seroconverters, lower serum HBsAg and HBV DNA levels have been shown to be associated with HBsAg loss over time. However, little is known about their impacts on HBsAg loss in HBeAg-negative patients with limited viral replication. A total of 688 HBeAg-negative patients with baseline serum HBV DNA levels loss were investigated. In a mean follow-up of 11.6 years, the average annual rate of HBsAg loss was 1.6%. Baseline HBsAg and HBV DNA levels were inversely associated with subsequent HBsAg loss. When compared to patients who had HBsAg levels >1000 IU/mL, the rates of HBsAg loss were significantly higher in patients with HBsAg levels of 100-999, 10-99, and loss was 13.2 (95% CI, 7.8-22.1) for HBsAg level loss. In HBeAg-negative patients with HBV genotype B or C infection who have HBV DNA level loss. Copyright © 2011 American Association for the Study of Liver Diseases.

  16. Cellular Cancer Vaccines: an Update on the Development of Vaccines Generated from Cell Surface Antigens

    Directory of Open Access Journals (Sweden)

    Petr G. Lokhov, Elena E. Balashova

    2010-01-01

    Full Text Available A recent advance in anti-cancer therapies has been the use of cancer cells to develop vaccines. However, immunization with cancer cell-based vaccines has not resulted in significant long-term therapeutic benefits. A possible reason for this is that while cancer cells provide surface antigens that are targets for a desired immune response, they also contain a high abundance of housekeeping proteins, carbohydrates, nucleic acids, lipids, and other intracellular contents that are ubiquitous in all mammalian cells. These ubiquitous molecules are not the intended targets of this therapy approach, and thus, the immune response generated is not sufficient to eliminate the cancer cells present. In this review, a discussion of the cell surface of cancer cells is presented in relation to the goals of improving antigen composition of cancer cell-based vaccines. Strategies to enrich vaccines for cancer-specific antigens are also discussed.

  17. In silico Analysis of Immunologic Regions of Surface Antigens (Sags of Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Abbas Alibakhshi

    2017-06-01

    Full Text Available Background: Surface antigens (SAGs of Toxoplasma gondii are known candidates for diagnostic tests and vaccines. The present study argues about the main necessary properties for determination and prediction of T-cell agretopes and B-cell epitopes of surface antigens of Toxoplasma gondii.Materials and Methods: Primary, secondary and tertiary structures of the proteins were analyzed by different methods. The three-dimensional structures were determined by use of ab initio method for prediction of discontinues epitopes. The agretopes and epitopes were predicted via several various web servers with different methods employed.Results: The results of in silico analyses showed that the regions 129-GAPAGRNNDGSSAPT-143 for protein p22, 234-SENPWQGNASSD-245 for protein p30 and 348-PGTEGESQAGT-358 for protein p43, have the highest immunogenic potential.Conclusion: We reached to three antigenic epitopes for cloning and protein expression. In following the purified polypeptide will be applied for diagnosis of Toxoplasma gondii.

  18. Hepatitis B-Surface Antigen In Ascitic Fluid Of Patients With Chronic ...

    African Journals Online (AJOL)

    A prospective evaluation of eleven consecutive cases of chronic liver disease over a twelve-month period was carried out clinically and ultrasonographically. By the use of the method of reverse passive haemagglutination, sera and ascitic fluid of the patients were tested for the presence of the Hepatitis B surface antigen.

  19. Prevalence of Hepatitis B Surface Antigen (HBsAg) Amongst Alcohol ...

    African Journals Online (AJOL)

    The prevalence of Hepatitis B surface Antigen was studied amongst alcohol consumers and non– consumers (Control subjects) in Bassa Local Government Area (LGA) of Plateau State. Three hundred and five (305) subjects comprising 255(83.61%) alcoholics and 50(16.39%) non-alcoholic control subjects were screened ...

  20. Identification and Characterization of Ixodes scapularis Antigens That Elicit Tick Immunity Using Yeast Surface Display

    NARCIS (Netherlands)

    Schuijt, T.J.; Narasimhan, S.; Daffre, S.; Deponte, K.; Hovius, J.W.R.; van 't Veer, C.; van der Poll, T.; Bakhtiari, K.; Meijers, J.C.M.; Boder, E.T.; van Dam, A.P.; Fikrig, E.

    2011-01-01

    Repeated exposure of rabbits and other animals to ticks results in acquired resistance or immunity to subsequent tick bites and is partially elicited by antibodies directed against tick antigens. In this study we demonstrate the utility of a yeast surface display approach to identify tick salivary

  1. Surface antigen-negative hepatitis B virus infection in Dutch blood donors

    NARCIS (Netherlands)

    Lieshout-Krikke, R. W.; Molenaar-de Backer, M. W. A.; van Swieten, P.; Zaaijer, H. L.

    2014-01-01

    Hepatitis B virus (HBV) surface antigen (HBsAg) is a reliable marker for HBV infection, but HBsAg-negative forms of HBV infection occur. The introduction of HBV DNA screening of Dutch blood donors, which were not preselected for absence of HBV core antibodies, enabled the characterization of

  2. Prevalence of Hepatitis-B Surface Antigen among Blood Donors in ...

    African Journals Online (AJOL)

    Information is scarce on the prevalence of Hepatitis-B Virus (HBV) infection among blood donors in Taraba State. Hepatitis-B surface antigen (HBsAg) ELISA [Gudans Industrial Hong 2 Kou, China] was used to determine the prevalence of HBsAg among 804 blood donors aged between 11 and 65 years in Federal Medical ...

  3. Multiple surface antigen mutations in five blood donors with occult hepatitis B virus infection

    NARCIS (Netherlands)

    Zaaijer, H. L.; Torres, P.; Ontañón, A.; Ponte, L. González; Koppelman, M. H. G. M.; Lelie, P. N.; Hemert, F. J. van; Boot, H. J.

    2008-01-01

    Occult hepatitis B virus (HBV) infection is characterized by the presence of HBV DNA while the HBV surface antigen (HBsAg) remains undetectable. The HBV genomes in five asymptomatic blood donors with occult HBV infection and low viremia ( <10 to 1,000 HBV DNA copies/mL, genotype D) were studied. An

  4. Prevalence of Hepatitis-B Surface Antigen (HbsAg), Hepatitis C ...

    African Journals Online (AJOL)

    The prevalence of Hepatitis-B surface antigen (HBsAg), Hepatitis C virus (HCV) and Human immunodeficiency virus (HIV) was determined among apparently healthy male blood donors in Aminu Kano Teaching Hospital, Kano, between January and December, 2002. A total of 2,288 blood samples from the blood donors ...

  5. A sensitive immunoradiometric assay for the detection of hepatitis B surface antigen

    International Nuclear Information System (INIS)

    Cameron, C.H.; Combridge, B.S.; Howell, D.R.; Barbara, J.A.J.

    1980-01-01

    A solid-phase immunoradiometric assay for hepatitis B surface antigen is described which has been in use since 1972. Initially it was used for reference laboratory work, but from 1974 it has also been used for screening blood and blood products. Methods for the production of reagents and their use in blood transfusion and reference work, are outlined. (Auth.)

  6. Method to conjugate polysaccharide antigens to surfaces for the detection of antibodies

    DEFF Research Database (Denmark)

    Boas, Ulrik; Lind, Peter; Riber, Ulla

    2014-01-01

    microbeads modified with N-alkyl hydroxylamine and N-alkyl-O-methyl hydroxylamine surface groups by incubation of antigen and beads for 16 h at 40 oC without the need for coupling agents. The efficiency of the new method was evaluated by flow cytometry in model samples and serum samples containing antibodies...

  7. Sero-prevalence of Hepatitis B Surface Antigen (HBsAg), in Sexually ...

    African Journals Online (AJOL)

    Sero-prevalence of Hepatitis B Surface Antigen (HBsAg), in Sexually Transmitted Disease Patients. ... partners in the past 6 months, a history of a number of episodes of STDs, history of heterosexual exposure to partners at risk, for example prostitutes; a history of symptoms of an STD at the commencement of the study.

  8. A Survey about Protective Effect of Echinococcus Granulosus Protoscolices Surface Antigens in Preventing Secondary Hydatid Cyst

    Directory of Open Access Journals (Sweden)

    H Yousofi

    2006-10-01

    Full Text Available ABSTRACT: Introduction & Objective: Hydatid cyst is located in human and some animal visceral organs such as liver and lung. The disease is considered as a medical, veterinary and economical problem in endemic area. When the hydatid cyst is ruptured, protoscolices from inside the cyst may spread out to other parts of the body and develops a new cyst named secondary hydatid cyst. In this research in an attempt to prevent secondary hydatid cyst, protective potential of protoscolices surface antigens extracted with different detergents has been investigated in animal model. Materials & Methods: In this experimental study, groups of Balb/c mice were immunized intra-peritoneally with protoscolices homogenate and three detergent (SDS, Tween and Triton x–100 extracted protoscolices surface antigens and alum as adjuvant. These mice were then boosted two times with the same antigens fortnightly. Control mice were simultaneously injected with alum alone. Two weeks following the last injection all the mice in cases and control groups were challenged with live protoscolices. Three months afterward all the mice in case and control groups were sacrificed and their peritoneal cavities were explored for hydatid cysts. Results: The mean of developed cyst number in mice injected with protoscolices homogenate was 3±2, while in control group the mean of developed cysts number was 5.8 ± 1.7 (p< 0.02. The mean of developed cyst number in mice injected with SDS, Tween and Triton x–100 extracted protoscolices surface antigens was 3, 3.6 and 3.4, respectively, while the mean of developed cyst number in control group was 5.8. Conclusion: The mean of cyst number in cases and control groups was different and this difference was statistically significant. Results of this investigation revealed that protoscolices homogenate antigens and some detergent extracted antigens are protective against secondary hydatid cyst infection

  9. Identification of Bacterial Surface Antigens by Screening Peptide Phage Libraries Using Whole Bacteria Cell-Purified Antisera

    Science.gov (United States)

    Hu, Yun-Fei; Zhao, Dun; Yu, Xing-Long; Hu, Yu-Li; Li, Run-Cheng; Ge, Meng; Xu, Tian-Qi; Liu, Xiao-Bo; Liao, Hua-Yuan

    2017-01-01

    Bacterial surface proteins can be good vaccine candidates. In the present study, we used polyclonal antibodies purified with intact Erysipelothrix rhusiopthiae to screen phage-displayed random dodecapeptide and loop-constrained heptapeptide libraries, which led to the identification of mimotopes. Homology search of the mimotope sequences against E. rhusiopthiae-encoded ORF sequences revealed 14 new antigens that may localize on the surface of E. rhusiopthiae. When these putative surface proteins were used to immunize mice, 9/11 antigens induced protective immunity. Thus, we have demonstrated that a combination of using the whole bacterial cells to purify antibodies and using the phage-displayed peptide libraries to determine the antigen specificities of the antibodies can lead to the discovery of novel bacterial surface antigens. This can be a general approach for identifying surface antigens for other bacterial species. PMID:28184219

  10. Variants of a Leishmania surface antigen derived from a multigenic family.

    Science.gov (United States)

    Murray, P J; Spithill, T W

    1991-12-25

    The promastigote surface antigen-2 (PSA-2) complex comprises a group of immunogenic surface antigens linked to the surface of the Leishmania major promastigote with glycosylphosphatidylinositol anchors. The L. major genome contains at least 14 PSA-2 genes on a 950-kilobase chromosome and comprising approximately 20% of the length of this chromosome. The sequence of three independent, but incomplete, PSA-2 cDNAs and one genomic fragment encoding a complete PSA-2 coding sequence were compared. PSA-2 genes encode polypeptides exhibiting 22-25aa tandem repeat elements, threonine-rich segments which vary between genes, a conserved COOH-terminal cysteine-rich region, and a conserved GPI anchor signal sequence. PSA-2 genes appear to be transcribed in a complex manner with multiple RNAs. The complex genomic organization of PSA-2 genes is present in other members of the genus suggesting that PSA-2 function is important for the biology of Leishmania.

  11. Identification and characterization of Ixodes scapularis antigens that elicit tick immunity using yeast surface display.

    Directory of Open Access Journals (Sweden)

    Tim J Schuijt

    2011-01-01

    Full Text Available Repeated exposure of rabbits and other animals to ticks results in acquired resistance or immunity to subsequent tick bites and is partially elicited by antibodies directed against tick antigens. In this study we demonstrate the utility of a yeast surface display approach to identify tick salivary antigens that react with tick-immune serum. We constructed an Ixodes scapularis nymphal salivary gland yeast surface display library and screened the library with nymph-immune rabbit sera and identified five salivary antigens. Four of these proteins, designated P8, P19, P23 and P32, had a predicted signal sequence. We generated recombinant (r P8, P19 and P23 in a Drosophila expression system for functional and immunization studies. rP8 showed anti-complement activity and rP23 demonstrated anti-coagulant activity. Ixodes scapularis feeding was significantly impaired when nymphs were fed on rabbits immunized with a cocktail of rP8, rP19 and rP23, a hall mark of tick-immunity. These studies also suggest that these antigens may serve as potential vaccine candidates to thwart tick feeding.

  12. Neospora caninum surface antigen (p40) is a potential diagnostic marker for cattle neosporosis.

    Science.gov (United States)

    He, Pengfei; Li, Jianhua; Gong, Pengtao; Liu, Chengwu; Zhang, Guocai; Yang, Ju; Tuo, Wenbin; Yang, Bintong; Zhang, Xichen

    2013-05-01

    Neospora caninum is an intracellular protozoan that infects domestic and wild canids as well as many warm-blooded animals as shown by the isolation of viable parasites. The effectiveness of diagnostic tests for detecting specific antibodies against N. caninum is hampered by potential cross-reaction with other Coccidia. So, there is currently an urgent need for a sensitive and specific diagnostic assay for detecting N. caninum in animals. The N. caninum 40-kD surface antigen (p40), similar to NcSAG1 and NcSRS2, was shown to belong to surface antigen super family and thus represents an excellent marker for the diagnosis of neosporosis. In order to test the hypothesis, recombinant Ncp40 (rNcp40) was expressed in Escherichia coli, and an indirect ELISA test was developed using recombinant NCp40 antigen for N. caninum serodiagnosis. The antigen used in this study did not have cross-reactivity with anti-Toxoplasma gondii serum. Anti-p40 antibodies were detected by ELISA in the sera of Yellow cattle and were compared with (IFAT). Optimal sensitivity and specificity (98.2 and 98.6 %) were identified by IFAT. Additionally, 37 positive sera of T. gondii were detected and there was no significant difference with the negative serum of N. caninum. The rNcp40 ELISA developed here provides a specific and sensitive assay for detecting neosporosis in cattle.

  13. A radioimmunoassay for antibodies against surface membrane antigens using adhering cells

    International Nuclear Information System (INIS)

    Tax, A.; Manson, L.A.

    1976-01-01

    A radioimmunoassay using cells adhering to plastic is described. In this assay, A-10 mammary carcinoma attached to the surface of plastic in microtiter plates were permitted to bind antibody and the bound antibody was detected with purified rabbit 125 I-antimouse-Fab. The bound radioactive material was eluted with glycine-HCl buffer (pH 2.5), and the acid eluates were counted in a gamma counter. This assay can be used to detect cytolic or noncytolic antibody to cell surface antigens in studies with any tumor or normal cell that will adhere to a solid surface

  14. The role of Plasmodium falciparum variant surface antigens in protective immunity and vaccine development

    DEFF Research Database (Denmark)

    Hviid, Lars

    2010-01-01

    that development of PfEMP1-based vaccines to protect specifically against severe malaria syndromes-in particular PAM-is feasible. This review summarizes the evidence that VSAs are important targets of NAI, discusses why VSA-based vaccines might be feasible despite the extensive intra- and interclonal variation...... of VSAs, and how vaccines based on this type of antigens fit into the current global strategy to reduce, eliminate and eventually eradicate the burden of malaria.......There is substantial immuno-epidemiological evidence that the parasite-encoded, so-called variant surface antigens (VSAs), such as PfEMP1 on the surface of infected erythrocytes (IEs) are important-in some cases probably decisive determinants of clinical outcome of P. falciparum malaria...

  15. High hepatitis B surface antigen levels predict insignificant fibrosis in hepatitis B e antigen positive chronic hepatitis B.

    Directory of Open Access Journals (Sweden)

    Wai-Kay Seto

    Full Text Available INTRODUCTION: There is no data on the relationship between hepatitis B surface antigen (HBsAg levels and liver fibrosis in hepatitis B e antigen (HBeAg-positive patients with chronic hepatitis B (CHB. METHODS: Serum HBsAg and HBV DNA levels in HBeAg-positive CHB patients with liver biopsies were analyzed. The upper limit of normal (ULN of alanine aminotransferase (ALT was 30 and 19 U/L for men and women respectively. Histologic assessment was based on Ishak fibrosis staging for fibrosis and Knodell histologic activity index (HAI for necroinflammation. RESULTS: 140 patients (65% male, median age 32.7 years were recruited. 56 (40% had ALT ≤2×ULN. 72 (51.4% and 42 (30% had fibrosis score ≤ 1 and necroinflammation grading ≤ 4 respectively. Patients with fibrosis score ≤ 1, when compared to patients with fibrosis score >1, had significantly higher median HBsAg levels (50,320 and 7,820 IU/mL respectively, p<0.001. Among patients with ALT ≤2×ULN, serum HBsAg levels achieved an area under receiver operating characteristic curve of 0.869 in predicting fibrosis score ≤ 1. HBsAg levels did not accurately predict necroinflammation score. HBsAg ≥ 25,000 IU/mL was independently associated with fibrosis score ≤ 1 (p=0.025, odds ratio 9.042.Using this cut-off HBsAg level in patients with ALT ≤2×ULN, positive and negative predictive values for predicting fibrosis score ≤ 1 were 92.7% and 60.0% respectively. HBV DNA levels had no association with liver histology. CONCLUSION: Among HBeAg-positive patients with ALT ≤2×ULN, high serum HBsAg levels can accurately predict fibrosis score ≤ 1, and could potentially influence decisions concerning treatment commencement and reduce the need for liver biopsy.

  16. KIR content genotypes associate with carriage of hepatitis B surface antigen, e antigen and HBV viral load in Gambians.

    Directory of Open Access Journals (Sweden)

    Louis-Marie Yindom

    Full Text Available Hepatocellular carcinoma (HCC causes over 800,000 deaths worldwide annually, mainly in low income countries, and incidence is rising rapidly in the developed world with the spread of hepatitis B (HBV and C (HCV viruses. Natural Killer (NK cells protect against viral infections and tumours by killing abnormal cells recognised by Killer-cell Immunoglobulin-like Receptors (KIR. Thus genes and haplotypes encoding these receptors may be important in determining both outcome of initial hepatitis infection and subsequent chronic liver disease and tumour formation. HBV is highly prevalent in The Gambia and the commonest cause of liver disease. The Gambia Liver Cancer Study was a matched case-control study conducted between September 1997 and January 2001 where cases with liver disease were identified in three tertiary referral hospitals and matched with out-patient controls with no clinical evidence of liver disease.We typed 15 KIR genes using the polymerase chain reaction with sequence specific primers (PCR-SSP in 279 adult Gambians, 136 with liver disease (HCC or Cirrhosis and 143 matched controls. We investigated effects of KIR genotypes and haplotypes on HBV infection and associations with cirrhosis and HCC.Homozygosity for KIR group A gene-content haplotype was associated with HBsAg carriage (OR 3.7, 95% CI 1.4-10.0 whilst telomeric A genotype (t-AA was associated with reduced risk of e antigenaemia (OR 0.2, 95% CI 0.0-0.6 and lower viral loads (mean log viral load 5.2 vs. 6.9, pc = 0.022. One novel telomeric B genotype (t-ABx2 containing KIR3DS1 (which is rare in West Africa was also linked to e antigenaemia (OR 8.8, 95% CI 1.3-60.5. There were no associations with cirrhosis or HCC.Certain KIR profiles may promote clearance of hepatitis B surface antigen whilst others predispose to e antigen carriage and high viral load. Larger studies are necessary to quantify the effects of individual KIR genes, haplotypes and KIR/HLA combinations on long

  17. KIR content genotypes associate with carriage of hepatitis B surface antigen, e antigen and HBV viral load in Gambians.

    Science.gov (United States)

    Yindom, Louis-Marie; Mendy, Maimuna; Bodimeade, Christopher; Chambion, Caroline; Aka, Peter; Whittle, Hilton C; Rowland-Jones, Sarah L; Walton, Robert

    2017-01-01

    Hepatocellular carcinoma (HCC) causes over 800,000 deaths worldwide annually, mainly in low income countries, and incidence is rising rapidly in the developed world with the spread of hepatitis B (HBV) and C (HCV) viruses. Natural Killer (NK) cells protect against viral infections and tumours by killing abnormal cells recognised by Killer-cell Immunoglobulin-like Receptors (KIR). Thus genes and haplotypes encoding these receptors may be important in determining both outcome of initial hepatitis infection and subsequent chronic liver disease and tumour formation. HBV is highly prevalent in The Gambia and the commonest cause of liver disease. The Gambia Liver Cancer Study was a matched case-control study conducted between September 1997 and January 2001 where cases with liver disease were identified in three tertiary referral hospitals and matched with out-patient controls with no clinical evidence of liver disease. We typed 15 KIR genes using the polymerase chain reaction with sequence specific primers (PCR-SSP) in 279 adult Gambians, 136 with liver disease (HCC or Cirrhosis) and 143 matched controls. We investigated effects of KIR genotypes and haplotypes on HBV infection and associations with cirrhosis and HCC. Homozygosity for KIR group A gene-content haplotype was associated with HBsAg carriage (OR 3.7, 95% CI 1.4-10.0) whilst telomeric A genotype (t-AA) was associated with reduced risk of e antigenaemia (OR 0.2, 95% CI 0.0-0.6) and lower viral loads (mean log viral load 5.2 vs. 6.9, pc = 0.022). One novel telomeric B genotype (t-ABx2) containing KIR3DS1 (which is rare in West Africa) was also linked to e antigenaemia (OR 8.8, 95% CI 1.3-60.5). There were no associations with cirrhosis or HCC. Certain KIR profiles may promote clearance of hepatitis B surface antigen whilst others predispose to e antigen carriage and high viral load. Larger studies are necessary to quantify the effects of individual KIR genes, haplotypes and KIR/HLA combinations on long

  18. An overview of serum prostatic surface antigen cut points for recommendation of prostatic biopsy

    OpenAIRE

    Patwardhan, Sujata K.; Patil, Bhushan P.; Shelke, Umesh Ravikant; Singh, Abhishek G.

    2018-01-01

    Introduction: Patients in India frequently present with prostatic surface antigen (PSA) report and request for prostatic biopsy to rule out malignancy. With fear of harboring malignancy set in patient's mind, it becomes difficult to counsel them about absolute indications and need of biopsy. Whether serum PSA has same predictability in symptomatic patients in the Indian context for advising prostatic biopsy at same reference ranges as in western countries, remains to be answered. Materials an...

  19. Characterization of a Monoclonal Antibody Specific for the Parasite Surface Antigen-2 of Leishmania major

    OpenAIRE

    "AR Khabiri; F Bagheri; SR Naddaf; M Assmar; A Hosseini Taghavi"

    2004-01-01

    The Leishmania major Parasite surface Antigen-2 (PSA-2) is a family of glycoinositol phospholipids anchored glycoprotoins expressed in both promastigotes and amastigotes. Promastigote PSA-2 comprises three polypeptides with approximate molecular weight of 96, 80 and 50 kDa. Amastigote express a distinct but closely PSA-2 polypeptide with molecular weight of 50 kDa. In this study fusion of SP2/0 myeloma cells with immunized mice spleenocytes infected with promastigotes of L. major intraperiton...

  20. Evaluation the Surface Antigen of the Salmonella typhimurium ATCC 14028 Ghosts Prepared by “SLRP”

    Directory of Open Access Journals (Sweden)

    Amara A. Amro

    2014-01-01

    Full Text Available Recently, bacterial ghosts (BGs were prepared using a protocol based on critical chemical concentrations. It has been given the name “sponge like” (SL protocol and used in its reduced form “sponge like reduced protocol” (SLRP. While specific antibody for Salmonella is available on the market under the commercial names (of some kits such as Febrile Antigen Kit (N.S. BIO-TEC, we used the described Kit to investigate the validity of the SLRP. In this study, using SLRP we succeeded to prepare STGs with correct surface antigens could interact with their specific antibodies. Additionally the study has included oral vaccination with STGs with challenge test. The rats serums have been evaluated against both of the O and H antigens. The antigen-antibody interaction (agglutination results of both the SLRP and the animal experiments prove that we have correct STGs able to immunize the rats against viable Salmonella. STGs could be used as vaccine and as adjuvant and in the antibodies and in the diagnostic kits production. This study is an additional step for the establishment of correct BGs for immunological purposes.

  1. Cell surface antigens of radiation leukemia virus-induced BALB/c leukemias defined by syngeneic cytotoxic T lymphocytes

    International Nuclear Information System (INIS)

    Kaneko, Yukio; Oettgen, H.F.; Obata, Yuichi; Nakayama, Eiichi.

    1989-01-01

    Two cell surface antigens of mouse leukemias were defined by BALB/c cytotoxic T lymphocytes (CTL) generated against syngeneic radiation leukemia virus (RadLV)-induced leukemia, BALBRV1 or BALBRVD. Hyperimmunization of BALB/c mice with irradiated leukemias followed by in vitro sensitization of primed spleen cells resulted in the generation of CTL with high killing activity. The specificity of CTL was examined by direct cytotoxicity assays and competitive inhibition assays. A shared cell surface antigen, designated as BALBRV1 antigen, was detected by BALB/c anti-BALBRV1 CTL. BALBRV1 antigen was expressed not only on RadLV-induced BALB/c leukemias except for BALBRVD, but also on spontaneous or X-ray-induced BALB/c leukemias, chemically-induced leukemias with the H-2 d haplotype and some chemically-induced BALB/c sarcomas. In contrast, a unique cell surface antigen, designated as BALBRVD antigen, was detected by BALB/c anti-BALBRVD CTL. BALBRVD antigen was expressed only on BALBRVD, but not on thirty-nine normal lymphoid or tumor cells. These two antigens could be distinguished from those previously defined on Friend, Moloney, Rauscher or Gross murine leukemia virus (MuLV) leukemias, or MuLV-related antigens. Both cytotoxic responses were blocked by antisera against H-2K d , but not H-2D d . The relationship of BALBRV1 antigen and BALBRVD antigen to endogenous MuLV is discussed with regard to the antigenic distribution on tumor cell lines. (author)

  2. Immuno disc assay for screening duck hepatitis B surface antigen in serum, liver tissue and cultured hepatocytes

    NARCIS (Netherlands)

    G.A. de Wilde (G.); R.A. Heijtink

    1993-01-01

    textabstractAn immuno disc assay (IDA) for semi-quantitative analysis of the surface antigen (DHBsAg) of duck hepatitis B virus (DHBV) is described. Unpurified antigen preparations were adsorbed onto punched-out nitrocellulose membrane discs. Rabbit antiserum raised against serum-derived

  3. Simulation and Theory of Antibody Binding to Crowded Antigen-Covered Surfaces.

    Directory of Open Access Journals (Sweden)

    Cristiano De Michele

    2016-03-01

    Full Text Available In this paper we introduce a fully flexible coarse-grained model of immunoglobulin G (IgG antibodies parametrized directly on cryo-EM data and simulate the binding dynamics of many IgGs to antigens adsorbed on a surface at increasing densities. Moreover, we work out a theoretical model that allows to explain all the features observed in the simulations. Our combined computational and theoretical framework is in excellent agreement with surface-plasmon resonance data and allows us to establish a number of important results. (i Internal flexibility is key to maximize bivalent binding, flexible IgGs being able to explore the surface with their second arm in search for an available hapten. This is made clear by the strongly reduced ability to bind with both arms displayed by artificial IgGs designed to rigidly keep a prescribed shape. (ii The large size of IgGs is instrumental to keep neighboring molecules at a certain distance (surface repulsion, which essentially makes antigens within reach of the second Fab always unoccupied on average. (iii One needs to account independently for the thermodynamic and geometric factors that regulate the binding equilibrium. The key geometrical parameters, besides excluded-volume repulsion, describe the screening of free haptens by neighboring bound antibodies. We prove that the thermodynamic parameters govern the low-antigen-concentration regime, while the surface screening and repulsion only affect the binding at high hapten densities. Importantly, we prove that screening effects are concealed in relative measures, such as the fraction of bivalently bound antibodies. Overall, our model provides a valuable, accurate theoretical paradigm beyond existing frameworks to interpret experimental profiles of antibodies binding to multi-valent surfaces of different sorts in many contexts.

  4. Antigenic variation and the genetics and epigenetics of the PfEMP1 erythrocyte surface antigens in Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Arnot, David E; Jensen, Anja T R

    2011-01-01

    How immunity to malaria develops remains one of the great unresolved issues in bio-medicine and resolution of its various paradoxes is likely to be the key to developing effective malaria vaccines. The basic epidemiological observations are; under conditions of intense natural transmission, humans...... on the function and control of this multi-gene family of parasite variable surface antigens....

  5. A putative, novel coli surface antigen 8B (CS8B) of enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Njoroge, Samuel M; Boinett, Christine J; Madé, Laure F; Ouko, Tom T; Fèvre, Eric M; Thomson, Nicholas R; Kariuki, Samuel

    2015-10-01

    Enterotoxigenic Escherichia coli (ETEC) strains harbor multiple fimbriae and pili to mediate host colonization, including the type IVb pilus, colonization factor antigen III (CFA/III). Not all colonization factors are well characterized or known in toxin positive ETEC isolates, which may have an impact identifying ETEC isolates based on molecular screening of these biomarkers. We describe a novel coli surface antigen (CS) 8 subtype B (CS8B), a family of CFA/III pilus, in a toxin producing ETEC isolate from a Kenyan collection. In highlighting the existence of this putative CS, we provide the sequence and specific primers, which can be used alongside other ETEC primers previously described. © FEMS 2015.

  6. Surface expression of Helicobacter pylori HpaA adhesion antigen on Vibrio cholerae, enhanced by co-expressed enterotoxigenic Escherichia coli fimbrial antigens.

    Science.gov (United States)

    Tobias, Joshua; Lebens, Michael; Wai, Sun Nyunt; Holmgren, Jan; Svennerholm, Ann-Mari

    2017-04-01

    Helicobacter pylori infection can cause peptic ulceration and is associated with gastric adenocarcinoma. This study aimed to construct and characterize a non-virulent Vibrio cholerae O1 strain, which grows more rapidly than H. pylori, as vector for H. pylori antigens for possible use as a vaccine strain against H. pylori. This was done by recombinant expression of the H. pylori adhesion antigen HpaA alone or, as a proof of principle, together with different colonization factor (CF) antigens of enterotoxigenic Escherichia coli (ETEC) which may enhance immune responses against HpaA. A recombinant V. cholerae strain co-expressing HpaA and a fimbrial CF antigens CFA/I or CS5, but not the non-fimbrial CF protein CS6, was shown to express larger amounts of HpaA on the surface when compared with the same V. cholerae strain expressing HpaA alone. Mutations in the CFA/I operon showed that the chaperon, possibly together with the usher, was involved in enhancing the surface expression of HpaA. Oral immunization of mice with formaldehyde-inactivated recombinant V. cholerae expressing HpaA alone or together with CFA/I induced significantly higher serum antibody responses against HpaA than mice similarly immunized with inactivated HpaA-expressing H. pylori bacteria. Our results demonstrate that a non-virulent V. cholerae strain can be engineered to allow strong surface expression of HpaA, and that the expression can be further increased by co-expressing it with ETEC fimbrial antigens. Such recombinant V. cholerae strains expressing HpaA, and possibly also other H. pylori antigens, may have the potential as oral inactivated vaccine candidates against H. pylori. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Effect of UV radiation on the surface of mammalian immunocompetent cells. 1. The change in expression of some antigens and receptors of murine spleen lymphocyte surface

    Energy Technology Data Exchange (ETDEWEB)

    Krylenkov, V.A.; Malygin, A.M. (AN SSSR, Leningrad. Inst. Tsitologii)

    1982-12-01

    Short-wave (254nm) and long-wave (365 nm) UV rays (ShUS and LUV rays) induce the increase in the expression of surface markers of T lymphocytes-THETA(Thy-1) antigens and B lymphocytes-MBLA-antigens and EAS receptors when affecting mouse spleen cells in nonlethal and small lethal doses. Total cell content with T and B lymphocyte characters in an irradiated suspension exceeds even the total cell quantity in non-irradiated suspension (100%) which points to the possibility of the expression of plasmatic membrane antigens and receptors not manifested on the surface of nonirradiated lymphocytes. In the isolethal dose range (LD/sup 15/-LD/sup 28/) ShUV rays suppress and LUV rays induce further increase of THETA and MBLA antigens expression. Among B lymphocytes surface markers the MBLA antigens are more resistant to ShUV an LUV radiation as compared with the EAC receptors.

  8. Surface-Engineering of Red Blood Cells as Artificial Antigen Presenting Cells Promising for Cancer Immunotherapy.

    Science.gov (United States)

    Sun, Xiaoqi; Han, Xiao; Xu, Ligeng; Gao, Min; Xu, Jun; Yang, Rong; Liu, Zhuang

    2017-10-01

    The development of artificial antigen presenting cells (aAPCs) to mimic the functions of APCs such as dendritic cells (DCs) to stimulate T cells and induce antitumor immune responses has attracted substantial interests in cancer immunotherapy. In this work, a unique red blood cell (RBC)-based aAPC system is designed by engineering antigen peptide-loaded major histocompatibility complex-I and CD28 activation antibody on RBC surface, which are further tethered with interleukin-2 (IL2) as a proliferation and differentiation signal. Such RBC-based aAPC-IL2 (R-aAPC-IL2) can not only provide a flexible cell surface with appropriate biophysical parameters, but also mimic the cytokine paracrine delivery. Similar to the functions of matured DCs, the R-aAPC-IL2 cells can facilitate the proliferation of antigen-specific CD8+ T cells and increase the secretion of inflammatory cytokines. As a proof-of-concept, we treated splenocytes from C57 mice with R-aAPC-IL2 and discovered those splenocytes induced significant cancer-cell-specific lysis, implying that the R-aAPC-IL2 were able to re-educate T cells and induce adoptive immune response. This work thus presents a novel RBC-based aAPC system which can mimic the functions of antigen presenting DCs to activate T cells, promising for applications in adoptive T cell transfer or even in direct activation of circulating T cells for cancer immunotherapy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Bacteroides gingivalis antigens and bone resorbing activity in root surface fractions of periodontally involved teeth

    International Nuclear Information System (INIS)

    Patters, M.R.; Landsberg, R.L.; Johansson, L.-A.; Trummel, C.L.; Robertson, P.R.

    1982-01-01

    Bone resorbing activity and the presence of antigens of Bacteroides gingivalis were assessed in plaque, calculus, cementum, and dentin obtained from roots of teeth previously exposed to periodontitis. Each fraction was obtained by scaling the root surface. The fraction were extracted by stirring and sonication, and the soluble centrifuged, sterilized, dialyzed, and adjusted to equivalent protein concentrations. Cementum and dentin extracts from impacted teeth were prepared similarly and served as controls. Stimulation of bone resorption by each extract was assessed in organ cultures of fetal rat bones by measurement of release of previously-incorporated 45 Ca from the bone into the medium. In some groups of teeth, calculus and cementum were treated with acid prior to scaling. Citric acid washes were recovered and dialyzed. An enzyme-linked immunosorbent assay (ELISA) was used to assess the extracts for the presence of antigens reactive with an antiserum to B. gingivalis. Significant stimulation of bone resorption was found in all calculus and periodontally-involved cementum preparations. ELISA showed significant levels of B.gingivalis antigens in plaque, calculus, and cementum of periodontally-involved teeth, but not in involved dentin nor in cementum or dentin of impact teeth. Treatment with citric acid removed essentially all B.gingivalis antigens from cementum but not calculus. The results suggest that substances which stimulate bone resorption and substances which react with B. gingivalis antiserum are present in surface plaque, calculus, and cementum or periodontally-involved teeth. These substances are not present in cementum and dentin of impacted teeth nor in dentin of periodontally-involved teeth. Treatment by both scaling and citric demineralization will remove most of these substances from cementum of teeth previously exposed to periodontitis. (author)

  10. Bacteroides gingivalis antigens and bone resorbing activity in root surface fractions of periodontally involved teeth

    Energy Technology Data Exchange (ETDEWEB)

    Patters, M.R.; Landsberg, R.L.; Johansson, L.A.; Trummel, C.L.; Robertson, P.R. (Department of Periodontology, University of Connecticut, School of Dental Medicine, Farmington, Connecticut, U.S.A.)

    1982-01-01

    Bone resorbing activity and the presence of antigens of Bacteroides gingivalis were assessed in plaque, calculus, cementum, and dentin obtained from roots of teeth previously exposed to periodontitis. Each fraction was obtained by scaling the root surface. The fraction were extracted by stirring and sonication, and the soluble centrifuged, sterilized, dialyzed, and adjusted to equivalent protein concentrations. Cementum and dentin extracts from impacted teeth were prepared similarly and served as controls. Stimulation of bone resorption by each extract was assessed in organ cultures of fetal rat bones by measurement of release of previously-incorporated /sup 45/Ca from the bone into the medium. In some groups of teeth, calculus and cementum were treated with acid prior to scaling. Citric acid washes were recovered and dialyzed. An enzyme-linked immunosorbent assay (ELISA) was used to assess the extracts for the presence of antigens reactive with an antiserum to B. gingivalis. Significant stimulation of bone resorption was found in all calculus and periodontally-involved cementum preparations. ELISA showed significant levels of B.gingivalis antigens in plaque, calculus, and cementum of periodontally-involved teeth, but not in involved dentin nor in cementum or dentin of impact teeth. Treatment with citric acid removed essentially all B.gingivalis antigens from cementum but not calculus. The results suggest that substances which stimulate bone resorption and substances which react with B. gingivalis antiserum are present in surface plaque, calculus, and cementum or periodontally-involved teeth. These substances are not present in cementum and dentin of impacted teeth nor in dentin of periodontally-involved teeth. Treatment by both scaling and citric demineralization will remove most of these substances from cementum of teeth previously exposed to periodontitis.

  11. Rapid and specific biotin labelling of the erythrocyte surface antigens of both cultured and ex-vivo Plasmodium parasites

    Directory of Open Access Journals (Sweden)

    Thompson Joanne

    2007-05-01

    Full Text Available Abstract Background Sensitive detection of parasite surface antigens expressed on erythrocyte membranes is necessary to further analyse the molecular pathology of malaria. This study describes a modified biotin labelling/osmotic lysis method which rapidly produces membrane extracts enriched for labelled surface antigens and also improves the efficiency of antigen recovery compared with traditional detergent extraction and surface radio-iodination. The method can also be used with ex-vivo parasites. Methods After surface labelling with biotin in the presence of the inhibitor furosemide, detergent extraction and osmotic lysis methods of enriching for the membrane fractions were compared to determine the efficiency of purification and recovery. Biotin-labelled proteins were identified on silver-stained SDS-polyacrylamide gels. Results Detergent extraction and osmotic lysis were compared for their capacity to purify biotin-labelled Plasmodium falciparum and Plasmodium chabaudi erythrocyte surface antigens. The pellet fraction formed after osmotic lysis of P. falciparum-infected erythrocytes is notably enriched in suface antigens, including PfEMP1, when compared to detergent extraction. There is also reduced co-extraction of host proteins such as spectrin and Band 3. Conclusion Biotinylation and osmotic lysis provides an improved method to label and purify parasitised erythrocyte surface antigen extracts from both in vitro and ex vivo Plasmodium parasite preparations.

  12. Naturally-acquired cellular immune response against Plasmodium vivax merozoite surface protein-1 paralog antigen.

    Science.gov (United States)

    Changrob, Siriruk; Leepiyasakulchai, Chaniya; Tsuboi, Takafumi; Cheng, Yang; Lim, Chae Seung; Chootong, Patchanee; Han, Eun-Taek

    2015-04-15

    Plasmodium vivax merozoite surface protein-1 paralog (PvMSP1P) is a glycosylphosphatidylinositol-anchored protein expressed on the merozoite surface. This molecule is a target of natural immunity, as high anti-MSP1P-19 antibody levels were detected during P. vivax infection and the antibody inhibited PvMSP1P-erythrocyte binding. Recombinant PvMSP1P antigen results in production of a significant Th1 cytokine response in immunized mice. The present study was performed to characterize natural cellular immunity against PvMSP1P-19 and PvDBP region II in acute and recovery P. vivax infection. Peripheral blood mononuclear cells (PBMCs) from acute and recovery P. vivax infection were obtained for lymphocyte proliferation assay upon PvMSP1P-19 and PvDBP region II antigen stimulation. The culture supernatant was examined for the presence of the cytokines IL-2, TNF, IFN-γ and IL-10 by enzyme-linked immunosorbent assay (ELISA). To determine whether Th1 or Th2 have a memory response against PvMSP1P-19 and PvDBPII protein antigen, PBMCs from subjects who had recovered from P. vivax infection 8-10 weeks prior to the study were obtained for lymphocyte proliferation assay. Cytokine-producing cells were analysed by flow cytometry. IL-2 was detected at high levels in lymphocyte cultures from acutely infected P. vivax patients upon PvMSP1P-19 stimulation. Analysis of the Th1 or Th2 memory response in PBMC cultures from subjects who had recovered from P. vivax infection showed significantly elevated levels of PvMSP1P-19 and PvDBPII-specific IFN-γ-producing cells (P  response of IFN-γ-producing cells in PvMSP1P stimulation was fourfold greater in recovered subjects than that in acute-infection patients. CD4(+) T cells were the major cell phenotype involved in the response to PvMSP1P-19 and PvDBPII antigen. PvMSP1P-19 strongly induces a specific cellular immune response for protection against P. vivax compared with PvDBPII as the antigen induces activation of IFN

  13. Heterologous expression of carcinoembryonic antigen in Lactococcus lactis via LcsB-mediated surface displaying system for oral vaccine development.

    Science.gov (United States)

    Zhang, Xiaowei; Hu, Shumin; Du, Xue; Li, Tiejun; Han, Lanlan; Kong, Jian

    2016-12-01

    Carcinoembryonic antigen (CEA) is an attractive target for immunotherapy because it is expressed minimally in normal tissue, but is overexpressed in a wide variety of malignant epithelial tissues. Lactic acid bacteria (LABs), widely used in food processes, are attractive candidates for oral vaccination. Thus, we examined whether LABs could be used as a live vaccine vector to deliver CEA antigen. CEA was cloned into an Escherichia coli/Lactococcus lactis shuttle vector pSEC:LEISS under the control of a nisin promoter. For displaying the CEA on the cell surface of the L. lactis strain, the anchor motif LcsB from the S-layer protein of Lactobacillus crispatus was fused with CEA. Intracellular and cell surface expression of the CEA-LcsB fusion was confirmed by western blot analysis. Significantly higher levels of CEA-specific secretory immunoglobulin A in the sera of mice were observed upon oral administration of strain cultures containing the CEA-LcsB fused protein. In addition, the CEA-LcsB antigen group showed a higher spleen index compared to the CEA antigen alone or negative control, demonstrating that surface-displayed CEA antigen could induce a higher immune response. These results provided the first evidence for displaying CEA antigen on the cell surfaces of LABs as oral vaccines against cancer or infectious diseases. Copyright © 2014. Published by Elsevier B.V.

  14. Analysis of Structures and Epitopes of Surface Antigen Glycoproteins Expressed in Bradyzoites of Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Hua Cong

    2013-01-01

    Full Text Available Toxoplasma gondii is a protozoan parasite capable of infecting humans and animals. Surface antigen glycoproteins, SAG2C, -2D, -2X, and -2Y, are expressed on the surface of bradyzoites. These antigens have been shown to protect bradyzoites against immune responses during chronic infections. We studied structures of SAG2C, -2D, -2X, and -2Y proteins using bioinformatics methods. The protein sequence alignment was performed by T-Coffee method. Secondary structural and functional domains were predicted using software PSIPRED v3.0 and SMART software, and 3D models of proteins were constructed and compared using the I-TASSER server, VMD, and SWISS-spdbv. Our results showed that SAG2C, -2D, -2X, and -2Y are highly homologous proteins. They share the same conserved peptides and HLA-I restricted epitopes. The similarity in structure and domains indicated putative common functions that might stimulate similar immune response in hosts. The conserved peptides and HLA-restricted epitopes could provide important insights on vaccine study and the diagnosis of this disease.

  15. Postvaccination seroconversion against the surface antigen of Hepatitis B virus, in nursing students

    Directory of Open Access Journals (Sweden)

    Gladys Amanda Mera-Urbano

    2013-09-01

    Full Text Available Objective: To determine the status of seroconversion after vaccination against the surface antigen of hepatitis B virus in nursing students, University of Cauca. Methods: Cross sectional study in students of V and VI semester. The sample was taken from 37 students, 15 of V and 22 of VI semester. The instrument used was a survey that included 11 questions of multiple selections. Records for weight, height and laboratory results were collected; blood samples for antibody titers were performed with informed consent. The data were tabulated and analyzed using SPSS, version 17.0. Results: 89.2% of students had levels of antibodies to the surface antigen. This value was greater than 10 mUI/ml, considered by the scientific community as a protector value of Hepatitis B. 10.8% of had lesser values. Regarding vaccination scheme, 24% had a dose, 19% two, 48% three and 8% had a one dose. The population with 3 doses and reinforcement seroconverted by 100%. Conclusion: This study demonstrated failings in the scheme of vaccination of the students of nursing and that 10.8 % presented lower values than 10 mIU/ml. It is necessary to apply the institutional rules with more strength as a preventive measure for hepatitis B.

  16. Recombinant forms of Leishmania amazonensis excreted/secreted promastigote surface antigen (PSA) induce protective immune responses in dogs

    OpenAIRE

    Petitdidier, Elodie; Pagniez, Julie; Papierok, Gérard; Vincendeau, Philippe; Lemesre, Jean-Loup; Bras-Gonçalves, Rachel

    2016-01-01

    International audience; Preventive vaccination is a highly promising strategy for interrupting leishmaniasis transmission that can, additionally, contribute to elimination. A vaccine formulation based on naturally excreted secreted (ES) antigens was prepared from L. infantum promastigote culture supernatant. This vaccine achieved successful results in Phase III trials and was licensed and marketed as CaniLeish. We recently showed that newly identified ES promastigote surface antigen (PSA), fr...

  17. Proteasomal targeting and minigene repetition improve cell-surface presentation of a transfected, modified melanoma tumour antigen

    DEFF Research Database (Denmark)

    Rasmussen, A B; Zocca, M-B; Bonefeld, C M

    2004-01-01

    on the density of specific major histocompatibility complex-peptide complexes on the surface of the antigen-presenting cell. In this study, we explored the cell-surface presentation of a substituted MART-1 peptide encoded by transfected minigenes. We investigated the potential of proteasomal targeting compared...

  18. Antigen processing of glycoconjugate vaccines; the polysaccharide portion of the pneumococcal CRM(197) conjugate vaccine co-localizes with MHC II on the antigen processing cell surface.

    Science.gov (United States)

    Lai, Zengzu; Schreiber, John R

    2009-05-21

    Pneumococcal (Pn) polysaccharides (PS) are T-independent (TI) antigens and do not induce immunological memory or antibodies in infants. Conjugation of PnPS to the carrier protein CRM(197) induces PS-specific antibody in infants, and memory similar to T-dependent (Td) antigens. Conjugates have improved immunogenicity via antigen processing and presentation of carrier protein with MHC II and recruitment of T cell help, but the fate of the PS attached to the carrier is unknown. To determine the location of the PS component of PnPS-CRM(197) in the APC, we separately labeled PS and protein and tracked their location. The PS of types 14-CRM(197) and 19F-CRM(197) was specifically labeled by Alexa Fluor 594 hydrazide (red). The CRM(197) was separately labeled red in a reaction that did not label PS. Labeled antigens were incubated with APC which were fixed, permeabilized and incubated with anti-MHC II antibody labeled green by Alexa Fluor 488, followed by confocal microscopy. Labeled CRM(197) was presented on APC surface and co-localized with MHC II (yellow). Labeled unconjugated 14 or 19F PS did not go to the APC surface, but PS labeled 14-CRM(197) and 19F-CRM(197) was internalized and co-localized with MHC II. Monoclonal antibody to type 14 PS bound to intracellular type 14 PS and PS-CRM(197). Brefeldin A and chloroquine blocked both CRM(197) and PS labeled 14-CRM(197) and 19F-CRM(197) from co-localizing with MHC II. These data suggest that the PS component of the CRM(197) glycoconjugate enters the endosome, travels with CRM(197) peptides to the APC surface and co-localizes with MHC II.

  19. Longitudinal microarray analysis of cell surface antigens on peripheral blood mononuclear cells from HIV+ individuals on highly active antiretroviral therapy

    Directory of Open Access Journals (Sweden)

    Wang Bin

    2008-03-01

    Full Text Available Abstract Background The efficacy of highly active antiretroviral therapy (HAART determined by simultaneous monitoring over 100 cell-surface antigens overtime has not been attempted. We used an antibody microarray to analyze changes in the expression of 135 different cell-surface antigens overtime on PBMC from HIV+ patients on HAART. Two groups were chosen, one (n = 6 achieved sustainable response by maintaining below detectable plasma viremia and the other (n = 6 responded intermittently. Blood samples were collected over an average of 3 years and 5–8 time points were selected for microarray assay and statistical analysis. Results Significant trends over time were observed for the expression of 7 cell surface antigens (CD2, CD3epsilon, CD5, CD95, CD36, CD27 and CD28 for combined patient groups. Between groups, expression levels of 10 cell surface antigens (CD11a, CD29, CD38, CD45RO, CD52, CD56, CD57, CD62E, CD64 and CD33 were found to be differential. Expression levels of CD9, CD11a, CD27, CD28 and CD52, CD44, CD49d, CD49e, CD11c strongly correlated with CD4+ and CD8+ T cell counts, respectively. Conclusion Our findings not only detected markers that may have potential prognostic/diagnostic values in evaluating HAART efficacy, but also showed how density of cell surface antigens could be efficiently exploited in an array-like manner in relation to HAART and HIV-infection. The antigens identified in this study should be further investigated by other methods such as flow cytometry for confirmation as biological analysis of these antigens may help further clarify their role during HAART and HIV infection.

  20. HMME-based PDT restores expression and function of transporter associated with antigen processing 1 (TAP1) and surface presentation of MHC class I antigen in human glioma.

    Science.gov (United States)

    Zhang, Shan-Yi; Li, Jun-Liang; Xu, Xin-Ke; Zheng, Mei-Guang; Wen, Cheng-Cai; Li, Fang-Cheng

    2011-11-01

    Numerous studies have established that photodynamic therapy (PDT) can trigger tumor-specific immunity and cancer cell immunogenicity, both of which play a critical role in the long-term control of oncogenesis; however, the underlying mechanisms are largely unexplained. Deficiency of the transporter associated with antigen processing 1 (TAP1) has been observed in a variety of tumors, and the question has been raised whether the restoration of TAP1 could facilitate the activation of antitumor immunity. To elucidate the mechanisms underlying PDT-induced immunopotentiation, we examined the hypothesis that upregulating TAP1 via PDT may contribute to enhancement of antitumor immunity and cancer cell immunogenicity. In this study, we investigated the effects of PDT on the expression and function of TAP1 in glioma cells. We found that HMME-based PDT restored TAP1 expression in a rapid and transient manner. Furthermore, the newly synthesized TAP1 protein was capable of potentiating the activity of transporting antigen peptides. As a result, restoration of the expression and function of TAP1 translated into augmenting the presentation of surface MHC class I molecules. Overall, our data indicate that PDT enables glioma cells to recover both the expression of functional TAP1 and the presentation of surface MHC class I antigens, which are processes that may enhance antitumor immunity after PDT. These findings may have implications for PDT and provide new insights into the mechanisms underlying PDT-induced immunopotentiation.

  1. Enhanced immunogenicity of DNA fusion vaccine encoding secreted hepatitis B surface antigen and chemokine RANTES

    International Nuclear Information System (INIS)

    Kim, Seung Jo; Suh, Dongchul; Park, Sang Eun; Park, Jeong-Sook; Byun, Hyang-Min; Lee, Chan; Lee, Sun Young; Kim, Inho; Oh, Yu-Kyoung

    2003-01-01

    To increase the potency of DNA vaccines, we constructed genetic fusion vaccines encoding antigen, secretion signal, and/or chemokine RANTES. The DNA vaccines encoding secreted hepatitis B surface antigen (HBsAg) were constructed by inserting HBsAg gene into an expression vector with an endoplasmic reticulum (ER)-targeting secretory signal sequence. The plasmid encoding secretory HBsAg (pER/HBs) was fused to cDNA of RANTES, generating pER/HBs/R. For comparison, HBsAg genes were cloned into pVAX1 vector with no signal sequence (pHBs), and further linked to the N-terminus of RANTES (pHBs/R). Immunofluorescence study showed the cytoplasmic localization of HBsAg protein expressed from pHBs and pHBs/R, but not from pER/HBs and pER/HBs/R at 48 h after transfection. In mice, RANTES-fused DNA vaccines more effectively elicited the levels of HBsAg-specific IgG antibodies than pHBs. All the DNA vaccines induced higher levels of IgG 2a rather than IgG 1 antibodies. Of RANTES-fused vaccines, pER/HBs/R encoding the secreted fusion protein revealed much higher humoral and CD8 + T cell-stimulating responses compared to pHBs/R. These results suggest that the immunogenicity of DNA vaccines could be enhanced by genetic fusion to a secretory signal peptide sequence and RANTES

  2. Liver Allograft Its Use in Chronic Active Hepatitis With Macronodular Cirrhosis, Hepatitis B Surface Antigen

    Science.gov (United States)

    Corman, Jarques L.; Putnam, Charles W.; Iwatsuki, Shunzaburo; Redeker, Allan G.; Porter, K. A.; Peters, Robert L.; Schröter, Gerhard; Starzl, Thomas E.

    2010-01-01

    A patient suffering from chronic active hepatitis with macronodular cirrhosis, positive for hepatitis B surface antigen (HB,Ag), was treated with an orthoiopic liver allograft. The HB, antigenemia, as measured with several precipltation tests and by complement fixation, became negative after transplantation and remained so for about 2½ months. During the interval, very low Iters of the antigen were detectable by, radioimmunoassay. At about three months after transplantation, she had an attack of acute hepatitis, at which time HB,Ag became detectable by all tests. She recovered, but progressive liver disease developed during the remaining 1½ years of her life. She died of disseminaled nocardiosis and candidiasis with deteriorating hepatic function. The homograft at autopsy, showed no evidence of rejection, but was the site of chronic active liver disease, although of a different pathologic pattern than that affecting her native liver. The differences in histology may reflect the influence of chronic Immunosuppression on the features of chronic active hepatitis. PMID:365134

  3. Salmonella regulates polyubiquitination and surface expression of MHC class II antigens.

    Science.gov (United States)

    Lapaque, Nicolas; Hutchinson, James L; Jones, Des C; Méresse, Stéphane; Holden, David W; Trowsdale, John; Kelly, Adrian P

    2009-08-18

    Salmonella typhimurium is a facultative pathogen capable of entering and replicating in both professional and non-professional antigen presenting cells. Control of infection requires MHC class II restricted CD4 T-helper cell responses. Here we show that Salmonella infection induced polyubiquitination of HLA-DR, a post-translational modification that led to removal of mature, peptide loaded, alphabeta dimers from the cell surface. Immature alphabetaIi complexes were unaffected. Surface expression of all class II isotypes, HLA-DP, -DQ, and -DR, was reduced in infected cells, but other cell-surface molecules that traffic through class II peptide loading compartments were unaffected. A Salmonella strain carrying a mutation in ssaV did not induce ubiquitination of class II, implicating Salmonella T3SS-2 effector proteins in the process. T3SS-2 effectors, with established or proposed roles in ubiquitination, were not required for class II down-regulation, suggesting that an additional T3SS-2 effector is involved in regulating MHC class II ubiquitination. Although recognized as a viral immune evasion strategy, here, we demonstrate that bacteria can control surface MHC expression through ubiquitination.

  4. Preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens and their use for bacterial detection.

    Science.gov (United States)

    Dykman, Lev A; Staroverov, Sergei A; Guliy, Olga I; Ignatov, Oleg V; Fomin, Alexander S; Vidyasheva, Irina V; Karavaeva, Olga A; Bunin, Viktor D; Burygin, Gennady L

    2012-01-01

    This article reports the first preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens by using a combinatorial phage library of sheep antibodies. The prepared phage antibodies were used for the first time for lipopolysaccharide and flagellin detection by dot assay, electro-optical analysis of cell suspensions, and transmission electron microscopy. Interaction of A. brasilense Sp245 with antilipopolysaccharide and antiflagellin phage-displayed miniantibodies caused the magnitude of the electro-optical signal to change considerably. The electro-optical results were in good agreement with the electron microscopic data. This is the first reported possibility of employing phage-displayed miniantibodies in bacterial detection aided by electro-optical analysis of cell suspensions.

  5. Identification of the Streptococcus pyogenes surface antigens recognised by pooled human immunoglobulin

    Science.gov (United States)

    Reglinski, Mark; Gierula, Magdalena; Lynskey, Nicola N.; Edwards, Robert J.; Sriskandan, Shiranee

    2015-01-01

    Immunity to common bacteria requires the generation of antibodies that promote opsonophagocytosis and neutralise toxins. Pooled human immunoglobulin is widely advocated as an adjunctive treatment for clinical Streptococcus pyogenes infection however, the protein targets of the reagent remain ill defined. Affinity purification of the anti-streptococcal antibodies present within pooled immunoglobulin resulted in the generation of an IgG preparation that promoted opsonophagocytic killing of S. pyogenes in vitro and provided passive immunity in vivo. Isolation of the streptococcal surface proteins recognised by pooled human immunoglobulin permitted identification and ranking of 94 protein antigens, ten of which were reproducibly identified across four contemporary invasive S. pyogenes serotypes (M1, M3, M12 and M89). The data provide novel insight into the action of pooled human immunoglobulin during invasive S. pyogenes infection, and demonstrate a potential route to enhance the efficacy of antibody based therapies. PMID:26508447

  6. A highly sensitive radioimmunoassay technique for subtyping the antibody to hepatitis B surface antigen

    International Nuclear Information System (INIS)

    Fang, C.T.; Nath, N.; Berberian, H.; Dodd, R.Y.

    1978-01-01

    A highly sensitive technique for determining the subtype specificity of antibody to hepatitis B surface antigen (anti-HBs) is described. Immunoadsorbent consisting of controlled pore glass coated with subtype specific HBsAg was used to remove homologous antibody from the test samples before testing them for residual antibody by a commercially available radioimmunoassay (RIA). A total of 73 anti-HBs-positive samples from asymptomatic blood donors were tested. In nearly 80% of these samples the subtype reactivity could be determined by this technique. Only 67% could be typed by conventional liquid phase absorption RIA and 22% by passive hemagglutination inhibition techniques. Among the samples with low anti-HBs titer, ad and ay subtypes were found with equal frequency; however, with the increase in anti-HBs titer, considerably higher proportion of ad specificity was detected. (Auth.)

  7. Malaria-induced acquisition of antibodies to Plasmodium falciparum variant surface antigens

    DEFF Research Database (Denmark)

    Ofori, Michael F; Dodoo, Daniel; Staalsoe, Trine

    2002-01-01

    In areas of intense Plasmodium falciparum transmission, protective immunity is acquired during childhood in parallel with acquisition of agglutinating antibodies to parasite-encoded variant surface antigens (VSA) expressed on parasitized red blood cells. In a semi-immune child in such an area......, clinical disease is caused mainly by parasites expressing VSA not recognized by preexisting VSA-specific antibodies in that child. Such malaria episodes are known to cause an increase in agglutinating antibodies specifically recognizing VSA expressed by the parasite isolate causing the illness, whereas...... antibody responses to other parasite isolates are relatively unaffected. However, the detailed kinetics of this VSA antibody acquisition are unknown and hence were the aim of this study. We show that P. falciparum malaria in Ghanaian children generally caused a rapid and sustained increase in variant...

  8. The Leishmania promastigote surface antigen 2 complex is differentially expressed during the parasite life cycle.

    Science.gov (United States)

    Handman, E; Osborn, A H; Symons, F; van Driel, R; Cappai, R

    1995-11-01

    The promastigote surface antigen 2 (PSA-2) complex comprises a family of antigenically similar polypeptides of M(r) 96,000, 80,000 and 50,000, anchored to the membrane with glycosylphosphatidylinositol. Although PSA-2 was initially detected only in promastigotes, Northern blot analysis indicated that mRNA transcripts are also present in amastigotes. Unlike the situation in promastigotes, where at least four major transcripts (2.6-5.3 kb) were detected, only one major (2.6 kb) and two minor transcripts were present in amastigotes. A cDNA clone encoding a member of the PSA-2 family expressed in amastigotes was isolated using DNA probes. The predicted protein sequence of M(r) 40,000 is distinct from promastigote sequences, but shows significant similarity to previously described members of the family from L major and L amazonensis. Antibodies to the carboxyl terminal sequence conserved in all L major PSA-2 studied to date, as well as antibodies affinity purified on the amastigote cDNA-derived polypeptide recognized a major M(r) 50,000 amastigote polypeptide. Immuno-electron microscopy localized both promastigote and amastigote PSA-2 to the cell surface. The expression of PSA-2 polypeptides during the transformation of amastigotes into promastigotes was ordered in a time-dependent manner, with the promastigote M(r) 80000 polypeptide appearing first, followed by the M(r) 96000 polypeptide. In contrast to the glycosylphosphatidylinositol anchor of promastigote PSA-2, which could be hydrolysed by phosphatidylinositol-specific phospholipase C, the amastigote form was resistant to this enzyme.

  9. A molecular analysis of viral persistence in surface antigen-negative chronic hepatitis B.

    Science.gov (United States)

    Kato, J; Hasegawa, K; Torii, N; Yamauchi, K; Hayashi, N

    1996-03-01

    To identify the mechanisms of viral persistence in patients with chronic hepatitis B after the acquisition of anti-hepatitis B surface antigen antibodies (antiHBs), we serially analyzed the nucleotide sequence of the envelope region in a cohort of infected patients. Four patients with histological diagnoses of chronic hepatitis B who had at least 5 years of observance by our hospital staff were studied. All but one showed normalization of serum alanine aminotransferase (ALT) concentration after clearance of the hepatitis B surface of antigen (HBsAg) and the appearance of anti-HBs. Hepatitis B virus (HBV) DNA was still detectable by polymerase chain reaction (PCR) amplification assay in serum specimens from two patients, even in the presence of circulating anti-HBs. The envelope gene was amplified by PCR in serum samples obtained both before and after seroconversion, and direct cycle sequencing of the PCR products was performed. A mutation resulting in a premature stop codon was found in the pre-S1 region of one patient just prior to clearance of HBsAg. Two years later, the stop codon was converted to a leucine codon and three mutations developed in the "a" loop. In the other patient, 16 amino acids had been deleted between amino acids 8 and 23 in the pre-S2 region before clearance of HBsAg. After the appearance of circulating anti-HBs, the pre-S2 gene reverted to the wild type but three additional mutations appeared inside the "a" loop. These results suggest that HBV mutates when HBsAg is cleared, which may contribute to viral persistence due to an evasion of the host immune surveillance.

  10. Antibodies to variable Plasmodium falciparum-infected erythrocyte surface antigens are associated with protection from novel malaria infections

    DEFF Research Database (Denmark)

    Giha, H A; Staalsoe, T; Dodoo, D

    2000-01-01

    is maintained at low densities. Here, we test the hypothesis that the presence or absence of antibodies against variant antigens on the surface of P. falciparum-infected erythrocytes protect individuals against some infectious challenges and render them susceptible to others. Plasma collected in Daraweesh...... susceptible and protected individuals. Together, the results indicate that pre-existing anti-PfEMP1 antibodies can reduce the risk of contracting clinical malaria when challenged by novel parasite clones expressing homologous, but not heterologous variable surface antigens. The results also confirm...

  11. Leishmania-specific surface antigens show sub-genus sequence variation and immune recognition.

    Directory of Open Access Journals (Sweden)

    Daniel P Depledge

    2010-09-01

    Full Text Available A family of hydrophilic acylated surface (HASP proteins, containing extensive and variant amino acid repeats, is expressed at the plasma membrane in infective extracellular (metacyclic and intracellular (amastigote stages of Old World Leishmania species. While HASPs are antigenic in the host and can induce protective immune responses, the biological functions of these Leishmania-specific proteins remain unresolved. Previous genome analysis has suggested that parasites of the sub-genus Leishmania (Viannia have lost HASP genes from their genomes.We have used molecular and cellular methods to analyse HASP expression in New World Leishmania mexicana complex species and show that, unlike in L. major, these proteins are expressed predominantly following differentiation into amastigotes within macrophages. Further genome analysis has revealed that the L. (Viannia species, L. (V. braziliensis, does express HASP-like proteins of low amino acid similarity but with similar biochemical characteristics, from genes present on a region of chromosome 23 that is syntenic with the HASP/SHERP locus in Old World Leishmania species and the L. (L. mexicana complex. A related gene is also present in Leptomonas seymouri and this may represent the ancestral copy of these Leishmania-genus specific sequences. The L. braziliensis HASP-like proteins (named the orthologous (o HASPs are predominantly expressed on the plasma membrane in amastigotes and are recognised by immune sera taken from 4 out of 6 leishmaniasis patients tested in an endemic region of Brazil. Analysis of the repetitive domains of the oHASPs has shown considerable genetic variation in parasite isolates taken from the same patients, suggesting that antigenic change may play a role in immune recognition of this protein family.These findings confirm that antigenic hydrophilic acylated proteins are expressed from genes in the same chromosomal region in species across the genus Leishmania. These proteins are

  12. IgM response to a human Pneumocystis carinii surface antigen in HIV-infected patients with pulmonary symptoms

    DEFF Research Database (Denmark)

    Lundgren, Bettina; Kovacs, J A; Mathiesen, Lars Reinhardt

    1993-01-01

    We have developed an ELISA to detect IgM antibodies to a major human Pneumocystis carinii surface antigen (gp95), and investigated the IgM response in 128 HIV-infected patients who underwent bronchoscopy for evaluation of pulmonary symptoms. Only 5 (4%) patients had IgM antibodies to P. carinii gp...... human P. carinii surface antigen. The increase in IgM response during the course of PCP observed in 3 patients suggests either reinfection with a new strain, or antigenic drift of an already acquired strain of P. carinii.......95. Four of the 5 patients with IgM antibodies also had IgG antibodies to gp95 and microbiologically proven P. carinii pneumonia (PCP). In 76/128 patients for whom serial samples were available, changes in antibody response were determined. In 3 patients we demonstrated an increase in IgM antibody...

  13. cDNA sequence analysis of a 29-kDa cysteine-rich surface antigen of pathogenic Entamoeba histolytica

    International Nuclear Information System (INIS)

    Torian, B.E.; Stroeher, V.L.; Stamm, W.E.; Flores, B.M.; Hagen, F.S.

    1990-01-01

    A λgt11 cDNA library was constructed from poly(U)-Spharose-selected Entamoeba histolytica trophozoite RNA in order to clone and identify surface antigens. The library was screened with rabbit polyclonal anti-E. histolytica serum. A 700-base-pair cDNA insert was isolated and the nucleotide sequence was determined. The deduced amino acid sequence of the cDNA revealed a cysteine-rich protein. DNA hybridizations showed that the gene was specific to E. histolytica since the cDNA probe reacted with DNA from four axenic strains of E. histolytica but did not react with DNA from Entamoeba invadens, Acanthamoeba castellanii, or Trichomonas vaginalis. The insert was subcloned into the expression vector pGEX-1 and the protein was expressed as a fusion with the C terminus of glutathione S-transferase. Purified fusion protein was used to generate 22 monoclonal antibodies (mAbs) and a mouse polyclonal antiserum specific for the E. histolytica portion of the fusion protein. A 29-kDa protein was identified as a surface antigen when mAbs were used to immunoprecipitate the antigen from metabolically 35 S-labeled live trophozoites. The surface location of the antigen was corroborated by mAb immunoprecipitation of a 29-kDa protein from surface- 125 I-labeled whole trophozoites as well as by the reaction of mAbs with live trophozoites in an indirect immunofluorescence assay performed at 4 degree C. Immunoblotting with mAbs demonstrated that the antigen was present on four axenic isolates tested. mAbs recognized epitopes on the 29-kDa native antigen on some but not all clinical isolates tested

  14. cDNA sequence analysis of a 29-kDa cysteine-rich surface antigen of pathogenic Entamoeba histolytica

    Energy Technology Data Exchange (ETDEWEB)

    Torian, B.E.; Stroeher, V.L.; Stamm, W.E. (Univ. of Washington, Seattle (USA)); Flores, B.M. (Louisiana State Univ. Medical Center, New Orleans (USA)); Hagen, F.S. (Zymogenetics Incorporated, Seattle, WA (USA))

    1990-08-01

    A {lambda}gt11 cDNA library was constructed from poly(U)-Spharose-selected Entamoeba histolytica trophozoite RNA in order to clone and identify surface antigens. The library was screened with rabbit polyclonal anti-E. histolytica serum. A 700-base-pair cDNA insert was isolated and the nucleotide sequence was determined. The deduced amino acid sequence of the cDNA revealed a cysteine-rich protein. DNA hybridizations showed that the gene was specific to E. histolytica since the cDNA probe reacted with DNA from four axenic strains of E. histolytica but did not react with DNA from Entamoeba invadens, Acanthamoeba castellanii, or Trichomonas vaginalis. The insert was subcloned into the expression vector pGEX-1 and the protein was expressed as a fusion with the C terminus of glutathione S-transferase. Purified fusion protein was used to generate 22 monoclonal antibodies (mAbs) and a mouse polyclonal antiserum specific for the E. histolytica portion of the fusion protein. A 29-kDa protein was identified as a surface antigen when mAbs were used to immunoprecipitate the antigen from metabolically {sup 35}S-labeled live trophozoites. The surface location of the antigen was corroborated by mAb immunoprecipitation of a 29-kDa protein from surface-{sup 125}I-labeled whole trophozoites as well as by the reaction of mAbs with live trophozoites in an indirect immunofluorescence assay performed at 4{degree}C. Immunoblotting with mAbs demonstrated that the antigen was present on four axenic isolates tested. mAbs recognized epitopes on the 29-kDa native antigen on some but not all clinical isolates tested.

  15. Enhanced cell disruption strategy in the release of recombinant hepatitis B surface antigen from Pichia pastoris using response surface methodology

    Directory of Open Access Journals (Sweden)

    Tam Yew

    2012-10-01

    Full Text Available Abstract Background Cell disruption strategies by high pressure homogenizer for the release of recombinant Hepatitis B surface antigen (HBsAg from Pichia pastoris expression cells were optimized using response surface methodology (RSM based on the central composite design (CCD. The factors studied include number of passes, biomass concentration and pulse pressure. Polynomial models were used to correlate the above mentioned factors to project the cell disruption capability and specific protein release of HBsAg from P. pastoris cells. Results The proposed cell disruption strategy consisted of a number of passes set at 20 times, biomass concentration of 7.70 g/L of dry cell weight (DCW and pulse pressure at 1,029 bar. The optimized cell disruption strategy was shown to increase cell disruption efficiency by 2-fold and 4-fold for specific protein release of HBsAg when compared to glass bead method yielding 75.68% cell disruption rate (CDR and HBsAg concentration of 29.20 mg/L respectively. Conclusions The model equation generated from RSM on cell disruption of P. pastoris was found adequate to determine the significant factors and its interactions among the process variables and the optimum conditions in releasing HBsAg when validated against a glass bead cell disruption method. The findings from the study can open up a promising strategy for better recovery of HBsAg recombinant protein during downstream processing.

  16. Enhanced cell disruption strategy in the release of recombinant hepatitis B surface antigen from Pichia pastoris using response surface methodology

    Science.gov (United States)

    2012-01-01

    Background Cell disruption strategies by high pressure homogenizer for the release of recombinant Hepatitis B surface antigen (HBsAg) from Pichia pastoris expression cells were optimized using response surface methodology (RSM) based on the central composite design (CCD). The factors studied include number of passes, biomass concentration and pulse pressure. Polynomial models were used to correlate the above mentioned factors to project the cell disruption capability and specific protein release of HBsAg from P. pastoris cells. Results The proposed cell disruption strategy consisted of a number of passes set at 20 times, biomass concentration of 7.70 g/L of dry cell weight (DCW) and pulse pressure at 1,029 bar. The optimized cell disruption strategy was shown to increase cell disruption efficiency by 2-fold and 4-fold for specific protein release of HBsAg when compared to glass bead method yielding 75.68% cell disruption rate (CDR) and HBsAg concentration of 29.20 mg/L respectively. Conclusions The model equation generated from RSM on cell disruption of P. pastoris was found adequate to determine the significant factors and its interactions among the process variables and the optimum conditions in releasing HBsAg when validated against a glass bead cell disruption method. The findings from the study can open up a promising strategy for better recovery of HBsAg recombinant protein during downstream processing. PMID:23039947

  17. Antibodies to variant antigens on the surfaces of infected erythrocytes are associated with protection from malaria in Ghanaian children

    DEFF Research Database (Denmark)

    Dodoo, D; Staalsoe, T; Giha, H

    2001-01-01

    Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant antigen expressed on the surface of infected erythrocytes. Each parasite genome contains about 40 PfEMP1 genes, but only 1 PfEMP1 gene is expressed at a given time. PfEMP1 serves as a parasite-sequestering ligand to endoth...

  18. Induction of protective immunity to Theileria annulata using two major merozoite surface antigens presented by different delivery systems

    NARCIS (Netherlands)

    C. D'Oliveira; A. Feenstra; H.W. Vos (Helma); A.D.M.E. Osterhaus (Albert); B.R. Shiels; A.W.C.A. Cornelissen; F. Jongejan

    1997-01-01

    textabstractAllelic forms (Tams1-1 and Tams1-2) of the major merozoite surface antigen gene of Theileria annulata have recently been expressed in Escherichia coli and in Salmonella typhimurium aroA vaccine strain SL3261. To test the potential of subunit vaccines against T. annulata infection, we

  19. The promastigote surface antigen gene family of the Leishmania parasite : differential evolution by positive selection and recombination - art. no. 292

    OpenAIRE

    Devault, A.; Banuls, Anne-Laure

    2008-01-01

    Background: PSA (promastigote surface antigen) is one of the major classes of membrane proteins present at the surface of the parasitic protozoan Leishmania. While it harbours leucine rich repeats, which are suggestive of its involvement in parasite-to-host physical interactions, its exact role is largely unknown. Furthermore, the extent of diversity of this gene family, both in copy number and sequence has not been established. Results: From the newly available complete genome sequences of L...

  20. A method for visualizing surface-exposed and internal PfEMP1 adhesion antigens in Plasmodium falciparum infected erythrocytes

    DEFF Research Database (Denmark)

    Bengtsson, Dominique; Sowa, Kordai M; Salanti, Ali

    2008-01-01

    -ionic detergent to permit access of antibodies to internal parasite antigens. Differentiation between surface and internal antigens is achieved using antibodies labelled with different fluorochromes and confocal microscopy RESULTS: Surface exposed PfEMP1 is first detectable by antibodies at the trophozoite stage...

  1. Quantitative Measurement of Serum Hepatitis B Surface Antigen Using an Immunoradiometric Assay in Chronic Hepatitis B

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyun Woo; Lee, Ho Young; Kim, Seog Gyun; Kim, Won; Jung, Wong Jin; Kang, Keon Wook; Chung, June Key; Lee, Myung Chul; Lee, Dong Soo [Seoul National Univ. Seoul (Korea, Republic of)

    2011-03-15

    Measurement of serum hepatitis B virus surface antigen (HBsAg) levels is important for the management of chronic hepatitis D patients in terms of monitoring response to antiviral therapy. This study aimed to evaluate the diagnostic performance of a new diagnostic kit, which quantitatively measures serum HBsAg level using an immunoradiometric assay (IRMA) based method. Measurements were compared with those obtained using a chemiluminescent microparticle immunoassay (CMIA) based method. The blood samples of 96 patients with chronic hepatitis B were used in this study. Copy numbers of serum hepatitis B virus (HBV) DNA were determined in 23 of these samples. The correlation between and the concordance of IRMA and CMIA results were determined using Pearson's correlation coefficients. P values of 0.05 were considered to be statistically significant throughout. Laboratory diagnoses based on CMIA. Furthermors, serum HBsAg levels by IRMA were found to be highly correlated with those determined by CMIA (correlation coefficient R{sup 2=}0.838, P<0.001). Serum HBsAg level and serum HBV DNA copies were found to be linearly related by both methods (R{sup 2=}0.067, P=0.316 by IRMA, and R{sup 2=}0.101, P=0.215 by CMIA). The diagnostic performance of the investigated IRMA method of determining HBsAg levels was found to be comparable with that of a CMIA based method in chronic hepatitis B patients.

  2. Hepatitis B Surface Antigen Seroprevalence among Children in Papua New Guinea, 2012–2013

    Science.gov (United States)

    Kitau, Russel; Sankar Datta, Siddhartha; Patel, Minal K.; Hennessey, Karen; Wannemuehler, Kathleen; Sui, Gerard; Lagani, William

    2015-01-01

    Approximately 8% of the population in Papua New Guinea (PNG) has chronic hepatitis B virus (HBV) infection. To decrease the burden of chronic HBV infection, a national 3-dose infant hepatitis B vaccination program was implemented starting in 1989, with a birth dose (BD) added to the schedule in 1992. To assess the impact of the hepatitis B vaccination program, we conducted a serosurvey among children born after vaccine introduction. During 2012–2013, a cross-sectional stratified four-stage cluster survey was conducted to estimate hepatitis B surface antigen (HBsAg) prevalence among children 4–6 years of age. We collected demographic data, vaccination history, and tested children for HBsAg. Of 2,133 participants, 2,130 children had vaccination data by either card or recall: 28% received a BD; 81% received ≥ 3 vaccine doses. Of 2,109 children providing a blood sample, 60 (2.3%) tested positive for HBsAg. This is the largest, most geographically diverse survey of hepatitis B vaccination and HBsAg seroprevalence done in PNG. Progress has been made in PNG toward the Western Pacific Regional goal to reduce the prevalence of chronic HBV infection to < 1% by 2017 among 5-year-old children. Vaccination efforts should be strengthened, including increasing BD coverage and completing the 3-dose series. PMID:25582692

  3. Sensitive prostate specific antigen quantification using dihydrolipoic acid surface-functionalized phosphorescent quantum dots.

    Science.gov (United States)

    García-Cortés, Marta; Fernández-Argüelles, María Teresa; Costa-Fernández, José M; Sanz-Medel, Alfredo

    2017-09-22

    Herein, high-quality Mn-doped ZnS quantum dots (QDs) have been synthesized using a facile approach directly in aqueous media. The surface of the obtained QDs was further modified by cap-exchange of the native cysteine shell with dihydrolipoic acid (DHLA) ligands resulting in nanocrystals with high water-stability having an intense phosphorescent signal. Covalent bioconjugation of the DHLA-coated nanoparticles with an anti-IgG antibody was then carried out. Interestingly the QD immunoprobe (QD-labelled antibodies) maintained an intense phosphorescence emission, without any significant spectral-shift (as compared to the free QDs). Coupling of an asymmetric flow field flow fractionation technique to an elemental mass spectrometry detection enabled the accurate determination of the efficiency of the bioconjugation reaction. The obtained nanoparticle-antibody bioconjugate was then applied to develop a quantitative sandwich-type phosphorescent immunoassay for Prostate Specific Antigen (PSA), and a limit of detection (LOD) of 17 pg mL -1 of PSA was achieved and allow to quantify such biomarker in samples within clinically relevant levels. Finally, the assay was validated for the quantification of PSA in the cellular media of prostate cancer cells. Obtained results proved the robustness of the proposed immunoassay based on long-lived phosphorescence measurements against eventual photoluminescent interferences significantly affecting the conventional short-lived fluorescence detection. Copyright © 2017. Published by Elsevier B.V.

  4. Increased parasite surface antigen-2 expression in clinical isolates of Leishmania donovani augments antimony resistance.

    Science.gov (United States)

    Bhandari, Vasundhra; Kumar, Dhiraj; Verma, Sandeep; Srividya, Gurumurthy; Negi, Narendra Singh; Singh, Ruchi; Salotra, Poonam

    2013-11-01

    Resistance to sodium antimony gluconate (SAG) is a major cause of therapeutic failure in a large proportion of visceral leishmaniasis (VL) cases. Determinants of SAG resistance have been widely studied; however, the mechanism operating in clinical isolates is poorly understood. In the present study, expression of parasite surface antigen-2 (PSA-2) gene was studied in clinical isolates of Leishmania donovani comprising of antimony resistant (n=10) and sensitive (n=4) parasites. The expression of PSA-2 gene was found to be consistently high in SAG resistant clinical isolates (≥1.5-fold) at both transcript and protein level. Further, over-expression of PSA-2 in L. donovani isolates (LdPSA-2(++)) resulted in conversion of SAG sensitive phenotype to resistant. The LdPSA-2(++) parasites showed significantly decreased susceptibility towards SAG (>12-fold), amphotericin B (>4-fold) and miltefosine (>2.5-fold). Marked decrease in antimony accumulation and enhanced tolerance towards complement mediated lysis was evident in LdPSA-2(++) parasites. The study established the role of PSA-2 gene in SAG resistance and its potential as a biomarker to distinguish resistant and sensitive clinical isolates of L. donovani. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Ultraviolet radiation (UVR) induces cell-surface Ro/SSA antigen expression by human keratinocytes in vitro: a possible mechanism for the UVR induction of cutaneous lupus lesions

    International Nuclear Information System (INIS)

    Jones, S.K.

    1992-01-01

    Antinuclear antibodies are useful markers of connective tissue disease. In this study, UVB but not UVA induced the expression of Ro/SSA antigen on keratinocyte surfaces in vitro. This expression was also found with the extractable nuclear antigens RnP and Sm, but not with single or double-stranded DNA. The expression was prevented by blocking protein synthesis, suggesting that it was an active process. The results suggest that UVB exposure may result in the expression of Ro/SSA antigen on the surfaces of basal keratinocytes in vivo. This antigen could then bind circulating antibody leading to the cutaneous lesions in neonatal and subacute cutaneous lupus erythematosus. (Author)

  6. Hepatitis B surface antigen variants in voluntary blood donors in Nanjing, China

    Directory of Open Access Journals (Sweden)

    Yong-lin Yang

    2012-04-01

    Full Text Available Abstract Background Hepatitis B virus (HBV is still one of the serious infectious risks for the blood transfusion safety in China. One plausible reason is the emergence of the variants in the major antigenic alpha determinant within the major hydrophilic region (MHR of hepatitis B surface antigen (HBsAg, which have been assumed to evade the immune surveillance and pose a challenge to the disease diagnosis. It is well documented that some commercial ELISA kits could detect the wild-type but not the mutant viruses. The high prevalence of HBV in China also impaired the application of nucleic acid testing (NAT in the improvement of blood security. Molecular epidemiological study of HBsAg variations in China is still limited. This study was designed to identify the prevalence of mutations in the HBsAg in voluntary blood donors in Nanjing, China. Methods A total of 20,326 blood units were enrolled in this study, 39 donors were positive for HBV S gene in the nested-PCR. Mutations in the major hydrophilic region (MHR; aa 99-169 were identified by direct sequencing of S region. Results Among of 20,326 blood units in the Red Cross Transfusion Center of Nanjing from October 2008 to April 2009, 296 samples (1.46%, 296/20,326 were HBsAg positive in the 2 successive rounds of the ELISA test. In these HBsAg positive units, HBV S gene could be successfully amplified from 39 donors (13.18%, 39/296 in the nested-PCR. Sequence analysis revealed that 32 strains (82.1%, 32/39 belong to genotype B, 7 strains (17.9%, 7/39 to genotype C. Besides well known G145R, widely dispersed variations in the MHR of S region, were observed in 20 samples of all the strains sequenced. Conclusions HBV/B and HBV/C are dominant in Nanjing, China. The mutations in the MHR of HBsAg associated with disease diagnosis are common.

  7. Performance evaluation of new automated hepatitis B viral markers in the clinical laboratory: two quantitative hepatitis B surface antigen assays and an HBV core-related antigen assay.

    Science.gov (United States)

    Park, Yongjung; Hong, Duck Jin; Shin, Saeam; Cho, Yonggeun; Kim, Hyon-Suk

    2012-05-01

    We evaluated quantitative hepatitis B surface antigen (qHBsAg) assays and a hepatitis B virus (HBV) core-related antigen (HBcrAg) assay. A total of 529 serum samples from patients with hepatitis B were tested. HBsAg levels were determined by using the Elecsys (Roche Diagnostics, Indianapolis, IN) and Architect (Abbott Laboratories, Abbott Park, IL) qHBsAg assays. HBcrAg was measured by using Lumipulse HBcrAg assay (Fujirebio, Tokyo, Japan). Serum aminotransferases and HBV DNA were respectively quantified by using the Hitachi 7600 analyzer (Hitachi High-Technologies, Tokyo, Japan) and the Cobas AmpliPrep/Cobas TaqMan test (Roche). Precision of the qHBsAg and HBcrAg assays was assessed, and linearity of the qHBsAg assays was verified. All assays showed good precision performance with coefficients of variation between 4.5% and 5.3% except for some levels. Both qHBsAg assays showed linearity from 0.1 to 12,000.0 IU/mL and correlated well (r = 0.9934). HBsAg levels correlated with HBV DNA (r = 0.3373) and with HBcrAg (r = 0.5164), and HBcrAg also correlated with HBV DNA (r = 0.5198; P < .0001). This observation could provide impetus for further research to elucidate the clinical usefulness of the qHBsAg and HBcrAg assays.

  8. Serological versus molecular typing of surface-associated immune evading polysaccharide antigens-based phenotypes of Staphylococcus aureus.

    Science.gov (United States)

    Waryah, Charlene B; Gogoi-Tiwari, Jully; Wells, Kelsi; Costantino, Paul; Al-Salami, Hani; Sunagar, Raju; Isloor, Shrikrishna; Hegde, Nagendra; Richmond, Peter; Mukkur, Trilochan

    2014-11-01

    The aim of this study was to compare the performance of serological versus molecular typing methods to detect capsular polysaccharide (CP) and surface-associated polysaccharide antigen 336 phenotypes of Staphylococcus aureus isolates. Molecular typing of CP types 1, 5 and 8 was carried out using PCR, whereas serological typing of CP1, 2, 5, 8 and antigen 336 was carried out by slide agglutination using specific antisera. By genotyping, 14/31 strains were CP8 positive, 12/31 strains were CP5 and the remaining 6/31 isolates were non-typable (NT). One isolate was positive for both CP5 and CP8 by PCR, but was confirmed as CP8 type serologically. Detection of CP2 and type 336 by PCR was not possible because specific primers were either not available or non-specific. Using serotyping, 14/31 strains were CP8 positive, 11/31 CP5 positive and 2/31 positive for antigen 336. The remaining four S. aureus isolates were serologically NT. However, three of four NT and two 336-positive S. aureus isolates were encapsulated as determined by light microscopy after capsular staining. This discovery was surprising and warrants further investigations on the identification and characterization of additional capsular phenotypes prevalent among S. aureus clinical isolates. It was concluded that serological typing was a better method than molecular typing for use in epidemiological investigations based upon the distribution of surface-associated polysaccharide antigens-based phenotypes. © 2014 The Authors.

  9. A novel merozoite surface antigen of Plasmodium falciparum (MSP-3 identified by cellular-antibody cooperative mechanism antigenicity and biological activity of antibodies

    Directory of Open Access Journals (Sweden)

    Claude Oeuvray

    1994-01-01

    Full Text Available We report the identification of a 48kDa antigen targeted by antibodies which inhibit Plasmodium falciparum in vitro growth by cooperation with blood monocytes in an ADCI assay correlated to the naturally acquired protection. This protein is located on the surface of the merozoite stage of P. falciparum, and is detectable in all isolates tested. Epidemiological studies demonstrated that peptides derived from the amino acid sequence of MSP-3 contain potent B and T-cell epitopes recognized by a majority of individuals living in endemic areas. Moreover human antibodies either purified on the recombinant protein, or on the synthetic peptide MSP-3b, as well as antibodies raised in mice, were all found to promote parasite killing mediated by monocytes.

  10. Serological responses to Cryptosporidium antigens in inhabitants of Hungary using conventionally filtered surface water and riverbank filtered drinking water.

    Science.gov (United States)

    Farkas, K; Plutzer, J; Moltchanova, E; Török, A; Varró, M J; Domokos, K; Frost, F; Hunter, P R

    2015-10-01

    In this study the putative protective seroprevalence (PPS) of IgG antibodies to the 27-kDa and 15/17-kDa Cryptosporidium antigens in sera of healthy participants who were and were not exposed to Cryptosporidium oocysts via surface water-derived drinking water was compared. The participants completed a questionnaire regarding risk factors that have been shown to be associated with infection. The PPS was significantly greater (49-61%) in settlements where the drinking water originated from surface water, than in the control city where riverbank filtration was used (21% and 23%). Logistic regression analysis on the risk factors showed an association between bathing/swimming in outdoor pools and antibody responses to the 15/17-kDa antigen complex. Hence the elevated responses were most likely due to the use of contaminated water. Results indicate that waterborne Cryptosporidium infections occur more frequently than reported but may derive from multiple sources.

  11. Prevalence of Hepatitis B surface antigen in children with sickle cell anemia

    Directory of Open Access Journals (Sweden)

    Baba Jibrin

    2014-01-01

    Full Text Available Background: Hepatitis B virus is known to be endemic in Africa. The seroepidemiological studies of HBV have shown that infection commonly occurs in childhood in Africa resulting in an increased tendency to chronicity. This cross-sectional study was undertaken to determine the seroprevalence of hepatitis B surface antigen among pediatric patients with homozygous hemoglobin S. Materials and Methods: Three hundred sickle cell anemia children aged 6 months-15 years (both in steady state and in crises attending the SCA clinic and on admission in emergency pediatrics unit and pediatrics medical ward, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria, were screened for hepatitis B infection using HBsAg as marker of infection. The sensitive enzyme linked immunosorbent assay method was used for detection of the marker. Three hundred children with minor illness attending pediatrics outpatient department and on admission in EPU/PMW for various treatment in the same hospital served as gender- and age-marched controls cohorts. Results: The sero-prevalence of HBsAg seropositivity for hepatitis B virus infection among SCA children was 17.3% (52/300 compared to 10.7% (32/300 of the control (P = 0.0875. The peak prevalence age group for HBV infection among SCA children was in the age group 1.1-5.0 years (6% compared to 10.1-15.0 years (4.7% in the control. Risk factors for HBV infection such as blood transfusion, traditional scarification/circumcision/uvulectomy, and tattooing did not significantly affect the prevalence of HBV infection in both SCA children and controls. Conclusion: Hepatitis B infection is common in Sokoto. The need for strict adherence to HBV immunization and further community-based studies on the risk factors are recommended.

  12. PRISM hepatitis B surface antigen detection of hepatits B virus minipool nucleic acid testing yield samples.

    Science.gov (United States)

    Linauts, Sandy; Saldanha, John; Strong, D Michael

    2008-07-01

    Hepatitis B virus (HBV) residual risk has been estimated at 1:63,000-1:205,000 and introduction of more sensitive serological tests and nucleic acid testing (NAT) would reduce that risk. Sensitivity of the recently licensed Abbott PRISM hepatitis B surface antigen (HBsAg) CLIA and minipool (MP) HBV NAT has been described as comparable and thus the need for HBV NAT has not been compelling. In this study, eight samples identified as yield samples with MP HBV NAT were tested using the PRISM test. Seven samples were identified using the Roche COBAS AmpliScreen HBV test and one additional sample was obtained from the clinical trial for the Roche cobas TaqScreen MPX test. Each of these samples was reactive by MP HBV NAT and nonreactive for HBsAg using one of three licensed enzyme immunoassay (EIA) tests. After licensure of the PRISM HBsAg, aliquots were tested with this assay, and DNA quantitation and genotyping were repeated where sample volume permitted. Three samples (2000, 2300, and 61,000 copies/mL) produced reactive results with PRISM. Four samples with viral loads less than 300 copies per mL produced nonreactive results. One sample, originally quantitated at 37,000 copies per mL (but 3850 copies/mL in repeat testing) was also nonreactive by PRISM. Genotyping of this sample indicated a type C genotype with no mutations. Adding serological sensitivity of PRISM CLIA reduced the NAT yield from the original 1: 385,555 to 1:610,488. However, MP HBV NAT still provides additional sensitivity over CLIA, even for a donation with a viral load of almost 4000 copies per mL.

  13. Diversity of Babesia bovis merozoite surface antigen genes in the Philippines.

    Science.gov (United States)

    Tattiyapong, Muncharee; Sivakumar, Thillaiampalam; Ybanez, Adrian Patalinghug; Ybanez, Rochelle Haidee Daclan; Perez, Zandro Obligado; Guswanto, Azirwan; Igarashi, Ikuo; Yokoyama, Naoaki

    2014-02-01

    Babesia bovis is the causative agent of fatal babesiosis in cattle. In the present study, we investigated the genetic diversity of B. bovis among Philippine cattle, based on the genes that encode merozoite surface antigens (MSAs). Forty-one B. bovis-positive blood DNA samples from cattle were used to amplify the msa-1, msa-2b, and msa-2c genes. In phylogenetic analyses, the msa-1, msa-2b, and msa-2c gene sequences generated from Philippine B. bovis-positive DNA samples were found in six, three, and four different clades, respectively. All of the msa-1 and most of the msa-2b sequences were found in clades that were formed only by Philippine msa sequences in the respective phylograms. While all the msa-1 sequences from the Philippines showed similarity to those formed by Australian msa-1 sequences, the msa-2b sequences showed similarity to either Australian or Mexican msa-2b sequences. In contrast, msa-2c sequences from the Philippines were distributed across all the clades of the phylogram, although one clade was formed exclusively by Philippine msa-2c sequences. Similarities among the deduced amino acid sequences of MSA-1, MSA-2b, and MSA-2c from the Philippines were 62.2-100, 73.1-100, and 67.3-100%, respectively. The present findings demonstrate that B. bovis populations are genetically diverse in the Philippines. This information will provide a good foundation for the future design and implementation of improved immunological preventive methodologies against bovine babesiosis in the Philippines. The study has also generated a set of data that will be useful for futher understanding of the global genetic diversity of this important parasite. © 2013.

  14. Higher lifetime chance of spontaneous surface antigen loss in hepatitis B carriers with genotype C infection.

    Science.gov (United States)

    Tseng, T-C; Liu, C-J; Chen, C-L; Yang, W-T; Yang, H-C; Su, T-H; Wang, C-C; Kuo, S F-T; Liu, C-H; Chen, P-J; Chen, D-S; Kao, J-H

    2015-05-01

    Clearance of hepatitis B surface antigen (HBsAg) indicates clinical control of hepatitis B virus (HBV) infection. However, little is known about the impact of viral genomic variations on HBsAg loss. We explored the association between viral genomic factors and HBsAg loss in 2121HBeAg-negative patients. HBV pre-core stop codon (1896) and basal core promoter (BCP) (1762/1764) sequences were determined in patients with HBV DNA ≥200 IU/mL (N = 1693). The effect of HBV genotype on HBsAg loss was further validated in the whole cohort of 3445 HBsAg carriers. The cumulative lifetime (age 28-75 years) incidence of HBsAg loss was 50.4% in 2121 HBeAg-negative patients. We found that genotype C, but not pre-core stop codon or BCP mutants, was associated with HBsAg loss. Compared to genotype B patients, genotype C patients had higher lifetime chance of HBsAg loss, with hazard ratio of 1.8 (95% confidence interval: 1.4-2.4). Multivariable analysis showed that male sex, elevated ALT levels, lower serum HBV DNA and HBsAg levels, and genotype C infection were associated with higher chance of HBsAg loss independently. We then performed sensitivity analysis, which re-included HBeAg-positive, cirrhotic and treatment-experienced patients, and confirmed the robustness of our results in 3445 HBsAg carriers. Genotype C infection, compared to genotype B, is associated with a higher lifetime chance of HBsAg loss in Asian HBV carriers. © 2015 John Wiley & Sons Ltd.

  15. An overview of serum prostatic surface antigen cut points for recommendation of prostatic biopsy.

    Science.gov (United States)

    Patwardhan, Sujata K; Patil, Bhushan P; Shelke, Umesh Ravikant; Singh, Abhishek G

    2018-01-01

    Patients in India frequently present with prostatic surface antigen (PSA) report and request for prostatic biopsy to rule out malignancy. With fear of harboring malignancy set in patient's mind, it becomes difficult to counsel them about absolute indications and need of biopsy. Whether serum PSA has same predictability in symptomatic patients in the Indian context for advising prostatic biopsy at same reference ranges as in western countries, remains to be answered. Symptomatic patients between 45 and 70 years of age presenting with either raised serum PSA (>4 ng/ml) reports or abnormal digital rectal examination (DRE) were considered as cases. Standard 12 core transrectal ultrasound-guided prostatic biopsy was done. Statistical analysis using optimal cut points, an R package was done to overview different PSA cut points for the recommendation of prostatic biopsy. A total of 534 patients were included. Mean age was 64 years. Malignancy was detected in total 77 patients (14.42%). Malignancy was identified in 3.59% (10/279) and 30% (63/210) patients at serum PSA ranges 4-10 ng/ml and serum PSA >10 ng/ml, respectively. Both, maximum sensitivity and specificity were found at PSA cut point 9.7 ng/ml. We evaluated these patients to identify the PSA cut point above which unnecessary biopsies will be avoided. We kept power of study maximum, i.e., 1 with confidence interval of 0.95. PSA value 9.7 ng/ml should be considered as the cut point above which prostatic biopsy should be done to avoid unnecessary biopsies. Unless accompanied by abnormal DRE finding at PSA range 4-10 ng/ml, morbidity of prostatic biopsy procedure can be avoided using this cut-point.

  16. Localization of immunodominant epitopes within the "a" determinant of hepatitis B surface antigen using monoclonal antibodies.

    Science.gov (United States)

    Golsaz-Shirazi, Forough; Mohammadi, Hamed; Amiri, Mohammad Mehdi; Khoshnoodi, Jalal; Kardar, Gholam Ali; Jeddi-Tehrani, Mahmood; Shokri, Fazel

    2016-10-01

    The common "a" determinant is the major immunodominant region of hepatitis B surface antigen (HBsAg) shared by all serotypes and genotypes of hepatitis B virus (HBV). Antibodies against this region are thought to confer protection against HBV and are essential for viral clearance. Mutations within the "a" determinant may lead to conformational changes in this region, which can affect the binding of neutralizing antibodies. There is an increasing concern about identification and control of mutant viruses which is possible by comprehensive structural investigation of the epitopes located within this region. Anti-HBs monoclonal antibodies (mAbs) against different epitopes of HBsAg are a promising tool to meet this goal. In the present study, 19 anti-HBs mAbs were employed to map epitopes localized within the "a" determinant, using a panel of recombinant mutant HBsAgs. The topology of the epitopes was analyzed by competitive enzyme-linked immunosorbent assay (ELISA). Our results indicate that all of the mAbs seem to recognize epitopes within or in the vicinity of the "a" determinant of HBsAg. Different patterns of binding with mutant forms were observed with different mAbs. Amino acid substitutions at positions 123, 126, 129, 144, and 145 dramatically reduced the reactivity of antibodies with HBsAg. The T123N mutation had the largest impact on antibody binding to HBsAg. The reactivity pattern of our panel of mAbs with mutant forms of HBsAg could have important clinical implications for immunoscreening, diagnosis of HBV infection, design of a new generation of recombinant HB vaccines, and immunoprophylaxis of HBV infection as an alternative to therapy with hepatitis B immune globulin (HBIG).

  17. Prevalence of Hepatitis B Surface Antigen in US-Born and Foreign-Born Asian/Pacific Islander College Students

    Science.gov (United States)

    Quang, Yen N.; Vu, Joanne; Yuk, Jihey; Li, Chin-Shang; Chen, Moon; Bowlus, Christopher L.

    2010-01-01

    The prevalence of chronic hepatitis B (HBV) among college-age US-born Asian and Pacific Islanders (A/PI) is not well known. Objectives: To compare the prevalence of hepatitis B surface antigen (HBsAg) seropositivity in US-born to A/PI-born students at a public university. Participants: Undergraduate who self-identified themselves as A/PI. Results:…

  18. Protective vaccination with promastigote surface antigen 2 from Leishmania major is mediated by a TH1 type of immune response.

    OpenAIRE

    Handman, E; Symons, F M; Baldwin, T M; Curtis, J M; Scheerlinck, J P

    1995-01-01

    Leishmania major promastigote surface antigen-2 complex (PSA-2) comprises a family of three similar but distinct polypeptides. The three PSA-2 polypeptides were purified from cultured promastigotes by a combination of detergent phase separation and monoclonal antibody affinity chromatography. Intraperitoneal vaccination of C3H/He mice with PSA-2 with Corynebacterium parvum as an adjuvant resulted in complete protection from lesion development after challenge infection with virulent L. major. ...

  19. In Vitro Evaluation of a Soluble Leishmania Promastigote Surface Antigen as a Potential Vaccine Candidate against Human Leishmaniasis

    OpenAIRE

    Chamakh-Ayari, Rym; Bras-Gonçalves, Rachel; Bahi-Jaber, Narges; Petitdidier, Elodie; Markikou-Ouni, Wafa; Aoun, Karim; Moreno, Javier; Carrillo, Eugenia; Salotra, Poonam; Kaushal, Himanshu; Negi, Narender Singh; Arevalo, Jorge; Falconi-Agapito, Francesca; Privat, Angela; Cruz, Maria

    2014-01-01

    PSA (Promastigote Surface Antigen) belongs to a family of membrane-bound and secreted proteins present in several Leishmania (L.) species. PSA is recognized by human Th1 cells and provides a high degree of protection in vaccinated mice. We evaluated humoral and cellular immune responses induced by a L. amazonensis PSA protein (LaPSA-38S) produced in a L. tarentolae expression system. This was done in individuals cured of cutaneous leishmaniasis due to L. major (CCLm) or L. braziliensis (CCLb)...

  20. Characterisation of peptide microarrays for studying antibody-antigen binding using surface plasmon resonance imagery.

    Directory of Open Access Journals (Sweden)

    Claude Nogues

    Full Text Available BACKGROUND: Non-specific binding to biosensor surfaces is a major obstacle to quantitative analysis of selective retention of analytes at immobilized target molecules. Although a range of chemical antifouling monolayers has been developed to address this problem, many macromolecular interactions still remain refractory to analysis due to the prevalent high degree of non-specific binding. We describe how we use the dynamic process of the formation of self assembling monolayers and optimise physical and chemical properties thus reducing considerably non-specific binding and allowing analysis of specific binding of analytes to immobilized target molecules. METHODOLOGY/PRINCIPAL FINDINGS: We illustrate this approach by the production of specific protein arrays for the analysis of interactions between the 65kDa isoform of human glutamate decarboxylase (GAD65 and a human monoclonal antibody. Our data illustrate that we have effectively eliminated non-specific interactions with the surface containing the immobilised GAD65 molecules. The findings have several implications. First, this approach obviates the dubious process of background subtraction and gives access to more accurate kinetic and equilibrium values that are no longer contaminated by multiphase non-specific binding. Second, an enhanced signal to noise ratio increases not only the sensitivity but also confidence in the use of SPR to generate kinetic constants that may then be inserted into van't Hoff type analyses to provide comparative DeltaG, DeltaS and DeltaH values, making this an efficient, rapid and competitive alternative to ITC measurements used in drug and macromolecular-interaction mechanistic studies. Third, the accuracy of the measurements allows the application of more intricate interaction models than simple Langmuir monophasic binding. CONCLUSIONS: The detection and measurement of antibody binding by the type 1 diabetes autoantigen GAD65 represents an example of an antibody-antigen

  1. Escherichia coli Nissle 1917 bacterial ghosts retain crucial surface properties and express chlamydial antigen: an imaging study of a delivery system for the ocular surface.

    Science.gov (United States)

    Montanaro, Jacqueline; Inic-Kanada, Aleksandra; Ladurner, Angela; Stein, Elisabeth; Belij, Sandra; Bintner, Nora; Schlacher, Simone; Schuerer, Nadine; Mayr, Ulrike Beate; Lubitz, Werner; Leisch, Nikolaus; Barisani-Asenbauer, Talin

    2015-01-01

    To target chronic inflammatory ocular surface diseases, a drug delivery platform is needed that is safe, possesses immunomodulatory properties, and can be used either for drug delivery, or as a foreign antigen carrier. A new therapeutic approach that we have previously proposed uses nonliving bacterial ghosts (BGs) as a carrier-delivery system which can be engineered to carry foreign antigens and/or be loaded with therapeutic drugs. The parent strain chosen for development of our BG delivery system is the probiotic Escherichia coli strain Nissle 1917 (EcN), whose intrinsic properties trigger the innate immune system with the flagella and fimbriae used to attach and stimulate epithelial cells. In previous studies, we have shown that EcN BGs are safe for the ocular surface route, but evidence that EcN BGs retain flagella and fimbriae after transformation, has never been visually confirmed. In this study, we used different visualization techniques to determine whether flagella and fimbriae are retained on EcN BGs engineered either for drug delivery or as a foreign antigen carrier. We have also shown by immunoelectron microscopy that EcN retains two foreign antigens after processing to become EcN BGs. Furthermore, we demonstrated that BGs derived from EcN and expressing a foreign antigen attachment to conjunctival epithelial cells in vitro without causing reduced cell viability. These results are an important step in constructing a delivery system based on a nonliving probiotic that is suitable for use in ocular surface diseases pairing immunomodulation and targeted delivery.

  2. Surface Antigen Profiling of Helicobacter pylori-Infected and -Uninfected Gastric Cancer Cells Using Antibody Microarray.

    Science.gov (United States)

    Sukri, Asif; Hanafiah, Alfizah; Kosai, Nik Ritza; Mohamed Taher, Mustafa; Mohamed Rose, Isa

    2016-10-01

    Comprehensive immunophenotyping cluster of differentiation (CD) antigens in gastric adenocarcinoma, specifically between Helicobacter pylori-infected and -uninfected gastric cancer patients by using DotScan(™) antibody microarray has not been conducted. Current immunophenotyping techniques include flow cytometry and immunohistochemistry are limited to the use of few antibodies for parallel examination. We used DotScan(™) antibody microarray consisting 144 CD antibodies to determine the distribution of CD antigens in gastric adenocarcinoma cells and to elucidate the effect of H. pylori infection toward CD antigen expression in gastric cancer. Mixed leukocytes population derived from gastric adenocarcinoma patients were immunophenotyped using DotScan(™) antibody microarray. AGS cells were infected with H. pylori strains and cells were captured on DotScan(™) slides. Cluster of differentiation antigens involved in perpetuating the tolerance of immune cells to tumor cells was upregulated in gastric adenocarcinoma cells compared to normal cells. CD279 which is essential in T cells apoptosis was found to be upregulated in normal cells. Remarkably, H. pylori-infected gastric cancer patients exhibited upregulated expression of CD27 that important in maintenance of T cells. Infection of cagA+ H. pylori with AGS cells increased CD antigens expression which involved in cancer stem cell while cagA- H. pylori polarized AGS cells to express immune-regulatory CD antigens. Increased CD antigens expression in AGS cells infected with cagA+ H. pylori were also detected in H. pylori-infected gastric cancer patients. This study suggests the tolerance of immune system toward tumor cells in gastric cancer and distinct mechanisms of immune responses exploited by different H. pylori strains. © 2016 John Wiley & Sons Ltd.

  3. Effect of a novel saponin adjuvant derived from Quillaja saponaria on the immune response to recombinant hepatitis B surface antigen.

    Science.gov (United States)

    So, H S; Yoon, H S; Choi, D Y; Kwon, Y S; Sung, J H; Lee, T G; Park, E S; Cho, H S; Lee, B M; Cho, J M; Ryu, W S

    1997-04-30

    Adjuvant activity of saponins extracted from the South American tree Quillaja saponaria has been demonstrated with many antigens. Recently, four saponin fractions (designated as QS-7, QS-17, QS-18, and QS-21) with adjuvant activity were purified by reverse phase chromatography. In particular, efficacy of the less toxic QS-21 fraction has been demonstrated with several recombinant viral antigens including HIV gp120. Here, we report a novel saponin fraction (designated as QS-L1) derived from Quillaja saponaria. Unlike previously identified saponins, QS-L1 had a different chemical structure and showed adjuvant activity only when administered in the presence of alum-precipitated antigen. Interestingly, the QS-L1 greatly increased not only a humoral immune response but also cellular immune response to recombinant hepatitis B virus surface antigen (HBsAg). Furthermore, QS-L1 showed lower toxicity in vivo and in vitro than the previously identified saponin fraction, QS-21. Finally, we examined the chemical structure of the QS-L1 using mass spectroscopic analysis, carbohydrate composition analysis and NMR spectroscopic analysis. Thus, our results indicated that this novel QS-L1 saponin fraction had several desirable properties required for an effective adjuvant.

  4. Novel Plasmodium falciparum malaria vaccines: evidence-based searching for variant surface antigens as candidates for vaccination against pregnancy-associated malaria

    DEFF Research Database (Denmark)

    Staalsoe, Trine; Jensen, Anja T R; Theander, Thor G

    2002-01-01

    Malaria vaccine development has traditionally concentrated on careful molecular, biochemical, and immunological characterisation of candidate antigens. In contrast, evidence of the importance of identified antigens in immunity to human infection and disease has generally been limited......) in particular, to provide robust evidence of a causal link between the two in order to allow efficient and evidence-based identification of candidate antigens for malaria vaccine development....... to statistically significant co-variation with protection rather than on demonstration of causal relationships. We have studied the relationship between variant surface antigen-specific antibodies and clinical protection from Plasmodium falciparum malaria in general, and from pregnancy-associated malaria (PAM...

  5. Trichinella britovi human infection in Spain : antibody response to surface, excretory/secretory and somatic antigens

    Directory of Open Access Journals (Sweden)

    Rodríguez-Osorio M.

    2003-06-01

    Full Text Available A third outbreak of Trichinella britovi with 140 people involved, occurred in Granada Spain (December 1998. The source of infection was sausage made from uninspected wild boar meat. Fifty-two patients agreed to participated in this study. An elevated eosinophil level (> 5 % was detected in 59.6 % of patients, and persisted in most of these cases for two months. A moderate IgG response was observed. At the onset of symptoms, Western blot (WB test detected more positive cases than Enzyme linked immunosorbent assay (ELISA and indirect immunofluorescence (IIF. Six months from infection, ELISA revealed fewer positive cases than the other two tests. It would appear that the response to somatic antigens starts earlier than those to cuticular and excretory/secretory (ES antigens and that the response to ES antigens is the first to decrease.

  6. Expression of myeloid antigens on lymphoblast surface in childhood acute lymphoblastic leukemia at diagnosis and its effect on early response to treatment: a preliminary report.

    Science.gov (United States)

    Sobol-Milejska, Grazyna; Mizia-Malarz, Agnieszka; Wos, Halina

    2013-09-01

    Immunodiagnosis of acute lymphoblastic leukemia (ALL) is based on the assessment of surface antigens. There are also cases in which both lymphoid and myeloid antigens can be found on the surface of lymphoblasts. The purpose of our research was to assess the expression of myeloid and lymphoblastic antigens in children with ALL, and to determine the impact of surface antigens on early response to treatment. 58 children [33 girls (56.9 %), 25 boys (43.2 %)] with ALL were studied. Response to treatment was assessed on days 8, 15, and 33. Univariate logistic regression analysis of the effect of myeloid antigens (MyAg) on response to treatment on days 8 and 33 revealed expression of any MyAg on lymphoblast surface as a factor associated with poor response to treatment. The multivariate logistic regression analysis of treatment response on day 33, showed that the expression of CD13 antigen on lymphoblast surface is a key factor affecting delayed remission (p = 0.03; odds ratio 0.12; 95 % CI 0.01-0.81). The expression of MyAg in childhood ALL adversely affects early response to treatment. The expression of CD13 antigen on day 33 is a key factor affecting complete remission in ALL patients.

  7. The Murine Humoral Immune Response to Hepatitis B Surface Antigen: Idiotype Network Pathways.

    Science.gov (United States)

    Schick, Michael Roy

    Recognition of a wide spectrum in disease outcomes following Hepatitis B Virus (HBV) infection has led to the suggestion that individual differences may be due to characteristics of the immune response. HBV, a hepatotropic virus, is not directly cytopathic to the host hepatocytes but the cellular damage which does not occur may be due to the host's own immune response. It is this variety in immune response capabilities following natural infection or vaccination which led to the present study in which the murine humoral immune response to hepatitis B surface antigen (HBsAg) was examined. Following immunization with purified HBsAg an anti-HBs response could be detected in 19 inbred strains of mice. The response, which varied among the strains, was linked to the major histocompatibility complex (MHC). Among high responders to HBsAg were two strains in which a poor response to a single epitope could be detected. Although quantitatively serum from these strains resembled serum from other high responders, there was a major difference in the qualitative aspects. Included within this study was the role of idotype networks within the murine anti-HBs response. By directly targeting HBsAg-specific B cells within the framework of an idiotype network by an Ab-2, it was possible to circumvent T cell-dependent regulation of an immune response. In each of five inbred strains of mice immunized with a polyclonal rabbit Ab-2 an Ab-3 population with HBsAg-specificity (Ab -1^') was induced. These mice were also immunized with HBsAg resulting in a higher anti-HBs response as compared to HBsAg immunization alone in all of the strains tested except for one. The response in this strain, normally a low responder to HBsAg, indicated that the mechanisms for genetic restriction of the anti -HBs response was still active, although it was not apparent during anti-Id immunization. The effects of an anti-Id on the murine antibody response to HBsAg may lead to insights on the presence of idiotype

  8. A 135-kilodalton surface antigen of Mycoplasma hominis PG21 contains multiple directly repeated sequences

    DEFF Research Database (Denmark)

    Ladefoged, Søren; Birkelund, Svend; Hauge, S

    1995-01-01

    -base substitution, C-->A, gave rise to the stop codon of lmp1. Thus, the C-terminal 945 amino acids were encoded by the 471-bp direct repeats. As evidenced by Southern blot analysis, the gene encoding the 135-kDa antigen is part of a multigene family. One of the genes, lmp2, was situated directly downstream from...

  9. Rapid screening and identification of dominant B cell epitopes of HBV surface antigen by quantum dot-based fluorescence polarization assay

    Science.gov (United States)

    Meng, Zhongji; Song, Ruihua; Chen, Yue; Zhu, Yang; Tian, Yanhui; Li, Ding; Cui, Daxiang

    2013-03-01

    A method for quickly screening and identifying dominant B cell epitopes was developed using hepatitis B virus (HBV) surface antigen as a target. Eleven amino acid fragments from HBV surface antigen were synthesized by 9-fluorenylmethoxy carbonyl solid-phase peptide synthesis strategy, and then CdTe quantum dots were used to label the N-terminals of all peptides. After optimizing the factors for fluorescence polarization (FP) immunoassay, the antigenicities of synthetic peptides were determined by analyzing the recognition and combination of peptides and standard antibody samples. The results of FP assays confirmed that 10 of 11 synthetic peptides have distinct antigenicities. In order to screen dominant antigenic peptides, the FP assays were carried out to investigate the antibodies against the 10 synthetic peptides of HBV surface antigen respectively in 159 samples of anti-HBV surface antigen-positive antiserum. The results showed that 3 of the 10 antigenic peptides may be immunodominant because the antibodies against them existed more widely among the samples and their antibody titers were higher than those of other peptides. Using three dominant antigenic peptides, 293 serum samples were detected for HBV infection by FP assays; the results showed that the antibody-positive ratio was 51.9% and the sensitivity and specificity were 84.3% and 98.2%, respectively. In conclusion, a quantum dot-based FP assay is a very simple, rapid, and convenient method for determining immunodominant antigenic peptides and has great potential in applications such as epitope mapping, vaccine designing, or clinical disease diagnosis in the future.

  10. Escherichia coli Nissle 1917 bacterial ghosts retain crucial surface properties and express chlamydial antigen: an imaging study of a delivery system for the ocular surface

    Directory of Open Access Journals (Sweden)

    Montanaro J

    2015-07-01

    Full Text Available Jacqueline Montanaro,1 Aleksandra Inic-Kanada,1 Angela Ladurner,1 Elisabeth Stein,1 Sandra Belij,1 Nora Bintner,1 Simone Schlacher,1 Nadine Schuerer,1 Ulrike Beate Mayr,2 Werner Lubitz,2 Nikolaus Leisch,3 Talin Barisani-Asenbauer11Laura Bassi Centres of Expertise, OCUVAC – Centre of Ocular Inflammation and Infection, Centre for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Vienna, Austria; 2BIRD-C GmbH & Co KG, Kritzendorf, Austria; 3Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, AustriaAbstract: To target chronic inflammatory ocular surface diseases, a drug delivery platform is needed that is safe, possesses immunomodulatory properties, and can be used either for drug delivery, or as a foreign antigen carrier. A new therapeutic approach that we have previously proposed uses nonliving bacterial ghosts (BGs as a carrier-delivery system which can be engineered to carry foreign antigens and/or be loaded with therapeutic drugs. The parent strain chosen for development of our BG delivery system is the probiotic Escherichia coli strain Nissle 1917 (EcN, whose intrinsic properties trigger the innate immune system with the flagella and fimbriae used to attach and stimulate epithelial cells. In previous studies, we have shown that EcN BGs are safe for the ocular surface route, but evidence that EcN BGs retain flagella and fimbriae after transformation, has never been visually confirmed. In this study, we used different visualization techniques to determine whether flagella and fimbriae are retained on EcN BGs engineered either for drug delivery or as a foreign antigen carrier. We have also shown by immunoelectron microscopy that EcN retains two foreign antigens after processing to become EcN BGs. Furthermore, we demonstrated that BGs derived from EcN and expressing a foreign antigen attachment to conjunctival epithelial cells in vitro without causing reduced cell viability. These results

  11. Identification of a novel dendritic cell surface antigen defined by carbohydrate specific CD24 antibody cross-reactivity.

    Science.gov (United States)

    Williams, L A; McLellan, A D; Summers, K L; Sorg, R V; Fearnley, D B; Hart, D N

    1996-01-01

    Dendritic cells (DC) are characterized as leucocytes that lack mature lineage specific markers and stimulate naive T-lymphocyte proliferation in vitro and in vivo. The mouse heat stable antigen (HSA) participates in T lymphocyte co-stimulation and is expressed by DC isolated from thymus, skin and spleen. The human HSA homologue, CD24, is predominantly expressed by B lymphocytes and granulocytes, but its expression on DC has not been studied in detail. CD24 clearly participates in B-lymphocyte signalling but co-stimulatory activity for T lymphocytes has not yet been described. We have examined the expression of CD24 on human peripheral blood DC populations isolated directly or following in vitro culture. The CD24 antigen was absent from blood DC however, cross-reactive sialylated carbohydrate epitopes were detected on DC with some CD24 monoclonal antibodies (mAb). These CD24 mAb define a protein surface antigen, which is expressed by an immature or resting subpopulation of peripheral blood DC and is down-regulated following activation differentiation in vitro. PMID:8911149

  12. Surface-enhanced Raman scattering study of carcinoembryonic antigen in serum from patients with colorectal cancers

    Science.gov (United States)

    Chen, Gang; Chen, Yanping; Zheng, Xiongwei; He, Cheng; Lu, Jianping; Feng, Shangyuan; Chen, Rong; Zeng, Haisan

    2013-12-01

    In this work, we developed a SERS platform for quantitative detection of carcinoembryonic antigen (CEA) in serum of patients with colorectal cancers. Anti-CEA-functionalized 4-mercaptobenzoic acid-labeled Au/Ag core-shell bimetallic nanoparticles were prepared first and then used to analyze CEA antigen solutions of different concentrations. A calibration curve was established in the range from 5 × 10-3 to 5 × 105 ng/mL. Finally, this new SERS probe was applied for quantitative detection of CEA in serum obtained from 26 colorectal cancer patients according to the calibration curve. The results were in good agreement with that obtained by electrochemical luminescence method, suggesting that SERS immunoassay has high sensitivity and specificity for CEA detection in serum. A detection limit of 5 pg/ml was achieved. This study demonstrated the feasibility and great potential for developing this new technology into a clinical tool for analysis of tumor markers in the blood.

  13. Evaluation of a Major Surface Antigen of Babesia microti Merozoites as a Vaccine Candidate against Babesia Infection

    Directory of Open Access Journals (Sweden)

    Suqin Man

    2017-12-01

    Full Text Available Babesia species are tick-borne intraerythrocytic protozoa that cause babesiosis in humans worldwide. No vaccine has yet proven effective against Babesia infection. Surface antigens of merozoites are involved in the invasion of erythrocytes by Babesia. Surface antigens may be presented by both babesial sporozoites and merozoites and provide a general target for antibody-mediated inhibition of erythrocyte invasion. Here we evaluated a major surface antigen of B. microti merozoites, BMSA, as a potential vaccine to prevent babesiosis. Our data indicated that bmsa is transcribed during different phases, including ring form, amoeboid form, and merozoites, and that its expression is significantly increased in mature merozoites. The protein was found to be located in the membrane of B. microti and in the cytoplasm of infected erythrocytes. The immune response induced by BMSA had a significant inhibitory effect on parasite invasion of the host erythrocytes (83.3% inhibition of invasion and parasite growth in vivo. The levels of parasitemia significantly decreased after BMSA vaccination when mice were infected with babesia parasite. Importantly, protective immunity was significantly related to the upregulation of the Th17 cytokine interleukin-17, the Th1 cytokine interleukin-12p70 and the Th2 cytokines, such as interleukin-4, -6, and -10. Ingenuity Pathway Analysis indicated that interleukin-17 facilitated the secretion of Th2 cytokines, such as interleukin-10, -4, and -6, thereby inducing a predominately Th2 protective immune response and promoting the expression a high level of special IgG1 against Babesia infection. Further, an anti-BMSA monoclonal antibody successfully protected NOD/SCID mice from a challenge with B. microti. Taken together, our results indicated that BMSA induces a protective immune response against Babesia infection and may serve as a potential vaccine.

  14. Seroprevalence of Hepatitis B Surface Antigen and Occupational Risk Factors Among Health Care Workers in Ekiti State, Nigeria

    Science.gov (United States)

    Alese, Oluwole Ojo; Ohunakin, Afolabi; Oluyide, Peter Olumuyiwa

    2016-01-01

    Introduction Hepatitis B virus (HBV) infection is contracted from blood and other body fluid making healthcare workers (HCW) prone to the infection especially in the developing world. Though it is a vaccine preventable disease, the level of awareness and universal precaution among HCW is low in sub-Saharan African and Asia. Aim The study was aimed at determining the seroprevalence of hepatitis B surface antigen and occupational risk factors among health care workers at Ekiti State University Teaching Hospital, Ado Ekiti. Materials and Methods One hundred and eighty-seven (187) blood samples were collected from volunteer subjects who comprised of medical doctors, nurses, health attendants, and porters who are in regular contact with blood, body fluids and patients after informed consent. Well detailed and structured questionnaires were used to obtain demographic and other relevant data from the subjects. Blood samples were tested by Enzyme Linked Immunosorbent assay (ELISA) for hepatitis B surface antigen. Results Out of the 187 HCWs there were 91 males (48.7%) and 96 (51.3%) females. Only 2 participants tested positive to hepatitis B surface antigen with a prevalence of 1.1%. Also, only 30 (16.0%) of the participants had been fully vaccinated against the infection while the remaining 157(84.0%) had no adult vaccination. Conclusion It is obvious that the awareness of the infection is low among the HCWs studied thus the need to incorporate screening for HbsAg and vaccination against HBV into the periodic/pre-employment health intervention programmes by employers to help in the protection of HCWs and control the spread of the virus. PMID:27042489

  15. Seroprevalence of Hepatitis B Surface Antigen and Occupational Risk Factors Among Health Care Workers in Ekiti State, Nigeria.

    Science.gov (United States)

    Alese, Oluwole Ojo; Alese, Margaret Olutayo; Ohunakin, Afolabi; Oluyide, Peter Olumuyiwa

    2016-02-01

    Hepatitis B virus (HBV) infection is contracted from blood and other body fluid making healthcare workers (HCW) prone to the infection especially in the developing world. Though it is a vaccine preventable disease, the level of awareness and universal precaution among HCW is low in sub-Saharan African and Asia. The study was aimed at determining the seroprevalence of hepatitis B surface antigen and occupational risk factors among health care workers at Ekiti State University Teaching Hospital, Ado Ekiti. One hundred and eighty-seven (187) blood samples were collected from volunteer subjects who comprised of medical doctors, nurses, health attendants, and porters who are in regular contact with blood, body fluids and patients after informed consent. Well detailed and structured questionnaires were used to obtain demographic and other relevant data from the subjects. Blood samples were tested by Enzyme Linked Immunosorbent assay (ELISA) for hepatitis B surface antigen. Out of the 187 HCWs there were 91 males (48.7%) and 96 (51.3%) females. Only 2 participants tested positive to hepatitis B surface antigen with a prevalence of 1.1%. Also, only 30 (16.0%) of the participants had been fully vaccinated against the infection while the remaining 157(84.0%) had no adult vaccination. It is obvious that the awareness of the infection is low among the HCWs studied thus the need to incorporate screening for HbsAg and vaccination against HBV into the periodic/pre-employment health intervention programmes by employers to help in the protection of HCWs and control the spread of the virus.

  16. Picomolar detection of carcinoembryonic antigen in whole blood using microfluidics and surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Zou, Kun; Gao, Zhigang; Deng, Quanfeng; Luo, Yong; Zou, Lijuan; Lu, Yao; Zhao, Weijie; Lin, Bingcheng

    2016-03-01

    Carcinoembryonic antigen (CEA) is a wide-spectrum biomarker. Clinically, we generally use serum sample to detect CEA, which needs to be centrifuged to pretreat the raw blood sample. In this study, we realized direct CEA detection in raw blood samples exploiting microfluidics. The LOD was as low as 10(-12) M. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Quantitative hepatitis B surface antigen combined with hepatitis B e antigen as sustained virological response predictors during extended therapy with Peginterferon alfa-2a for hepatitis B e antigen-positive chronic hepatitis B.

    Science.gov (United States)

    Chen, Jie; Zhang, Dong-Hua; Xu, Cheng-Run; Zhu, Ming-Yu; Yang, Zhi-Tao; Gong, Qi-Ming; Yu, De-Min; Zhang, Xin-Xin

    2015-11-01

    The best strategy for chronic hepatitis B patients with poor response to 48 weeks of Peginterferon-based therapy has been controversial and the predictive value of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA levels for determining the sustained virological response (SVR) of these patients is uncertain. To optimize management of these patients and evaluate the use of these serobiomarkers to predict SVR. Eighty-one patients with an unsatisfactory response after 48 weeks of Peginterferon-based therapy were treated with extended Peginterferon therapy with or without nucleo(s) tide analogues (NAs), for a total of 96 weeks of Peginterferon treatment. HBsAg, HBeAg and HBV DNA levels were measured serially during the treatment and follow-up. Twenty-six of 81 patients (32.1%) attained SVR during the 72-week follow-up. The SVR rate was not statistically different between groups receiving 1-year prolongation of Peginterferon with or without NAs. The serum HBsAg cut-off of 1800IU/mL at week 48 had area under curve (AUC) of 0.727, and the serum HBsAg cut-off of 1500IU/mL, combined with HBeAg loss at week 72, had AUC of 0.753 to predict SVR during the follow-up. In conclusion, extended treatment with Peginterferon with or without NAs for patients with unsatisfactory response after 48 weeks of Peginterferon-based therapy is a promising strategy to achieve SVR, and quantitative serum HBsAg at week 48 and HBsAg level combined with HBeAg loss at week 72 of therapy can predict SVR to prolongation therapy with Peginterferon. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Circulating Gut-Homing (α4β7+) Plasmablast Responses against Shigella Surface Protein Antigens among Hospitalized Patients with Diarrhea.

    Science.gov (United States)

    Sinha, Anuradha; Dey, Ayan; Saletti, Giulietta; Samanta, Pradip; Chakraborty, Partha Sarathi; Bhattacharya, M K; Ghosh, Santanu; Ramamurthy, T; Kim, Jae-Ouk; Yang, Jae Seung; Kim, Dong Wook; Czerkinsky, Cecil; Nandy, Ranjan K

    2016-07-01

    Developing countries are burdened with Shigella diarrhea. Understanding mucosal immune responses associated with natural Shigella infection is important to identify potential correlates of protection and, as such, to design effective vaccines. We performed a comparative analysis of circulating mucosal plasmablasts producing specific antibodies against highly conserved invasive plasmid antigens (IpaC, IpaD20, and IpaD120) and two recently identified surface protein antigens, pan-Shigella surface protein antigen 1 (PSSP1) and PSSP2, common to all virulent Shigella strains. We examined blood and stool specimens from 37 diarrheal patients admitted to the Infectious Diseases & Beliaghata General Hospital, Kolkata, India. The etiological agent of diarrhea was investigated in stool specimens by microbiological methods and real-time PCR. Gut-homing (α4β7 (+)) antibody-secreting cells (ASCs) were isolated from patient blood by means of combined magnetic cell sorting and two-color enzyme-linked immunosorbent spot (ELISPOT) assay. Overall, 57% (21 of 37) and 65% (24 of 37) of the patients were positive for Shigella infection by microbiological and real-time PCR assays, respectively. The frequency of α4β7 (+) IgG ASC responders against Ipas was higher than that observed against PSSP1 or PSSP2, regardless of the Shigella serotype isolated from these patients. Thus, α4β7 (+) ASC responses to Ipas may be considered an indirect marker of Shigella infection. The apparent weakness of ASC responses to PSSP1 is consistent with the lack of cross-protection induced by natural Shigella infection. The finding that ASC responses to IpaD develop in patients with recent-onset shigellosis indicates that such responses may not be protective or may wane too rapidly and/or be of insufficient magnitude. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  19. Well-known surface and extracellular antigens of pathogenic microorganisms among the immunodominant proteins of the infectious microalgae Prototheca zopfii.

    Science.gov (United States)

    Irrgang, Alexandra; Murugaiyan, Jayaseelan; Weise, Christoph; Azab, Walid; Roesler, Uwe

    2015-01-01

    Microalgae of the genus Prototheca (P.) are associated with rare but severe infections (protothecosis) and represent a potential zoonotic risk. Genotype (GT) 2 of P. zopfii has been established as pathogenic agent for humans, dogs, and cattle, whereas GT1 is considered to be non-pathogenic. Since pathogenesis is poorly understood, the aim of this study was to determine immunogenic proteins and potential virulence factors of P. zopfii GT2. Therefore, 2D western blot analyses with sera and isolates of two dogs naturally infected with P. zopfii GT2 have been performed. Cross-reactivity was determined by including the type strains of P. zopfii GT2, P. zopfii GT1, and P. blaschkeae, a close relative of P. zopfii, which is known to cause subclinical forms of bovine mastitis. The sera showed a high strain-, genotype-, and species-cross-reactivity. A total of 198 immunogenic proteins have been analyzed via MALDI-TOF MS. The majority of the 86 identified proteins are intracellularly located (e.g., malate dehydrogenase, oxidoreductase, 3-dehydroquinate synthase) but some antigens and potential virulence factors, known from other pathogens, have been found (e.g., phosphomannomutase, triosephosphate isomerase). One genotype-specific antigen could be identified as heat shock protein 70 (Hsp70), a well-known antigen of eukaryotic pathogens with immunological importance when located extracellularly. Both sera were reactive to glyceraldehyde-3-phosphate-dehydrogenase of all investigated strains. This house-keeping enzyme is found to be located on the surface of several pathogens as virulence factor. Flow-cytometric analysis revealed its presence on the surface of P. blaschkeae.

  20. Well-known surface and extracellular antigens of pathogenic microorganisms among the immunodominant proteins of the infectious microalgae Prototheca zopfii

    Directory of Open Access Journals (Sweden)

    Alexandra eIrrgang

    2015-09-01

    Full Text Available Microalgae of the genus Prototheca (P. are associated with rare but severe infections (protothecosis and represent a potential zoonotic risk. Genotype (GT 2 of P. zopfii has been established as pathogenic agent for humans, dogs and cattle, whereas GT1 is considered to be non-pathogenic. Since pathogenesis is poorly understood, the aim of this study was to determine immunogenic proteins and potential virulence factors of P. zopfii GT2. Therefore, 2D western blot analyses with sera and isolates of two dogs naturally infected with P. zopfii GT2 have been performed. Cross-reactivity was determined by including the type strains of P. zopfii GT2, P. zopfii GT1 and P. blaschkeae, a close relative of P. zopfii, which is known to cause subclinical forms of bovine mastitis. The sera showed a high strain-, genotype-, and species-cross-reactivity. A total of 198 immunogenic proteins have been analysed via MALDI- TOF MS. The majority of the 86 identified proteins are intracellularly located (e.g. malate dehydrogenase, oxidoreductase, 3-dehydroquinate synthase but some antigens and potential virulence factors, known from other pathogens, have been found (e.g. phosphomannomutase, triosephosphate isomerase. One genotype-specific antigen could be identified as heat shock protein 70 (Hsp70, a well-known antigen of eukaryotic pathogens with immunological importance when located extracellularly. Both sera were reactive to glyceraldehyde-3-phosphate-dehydrogenase of all investigated strains. This house-keeping enzyme is found to be located on the surface of several pathogens as virulence factor. Flow-cytometric analysis revealed its presence on the surface of P. blaschkeae.

  1. A single point in protein trafficking by Plasmodium falciparum determines the expression of major antigens on the surface of infected erythrocytes targeted by human antibodies.

    Science.gov (United States)

    Chan, Jo-Anne; Howell, Katherine B; Langer, Christine; Maier, Alexander G; Hasang, Wina; Rogerson, Stephen J; Petter, Michaela; Chesson, Joanne; Stanisic, Danielle I; Duffy, Michael F; Cooke, Brian M; Siba, Peter M; Mueller, Ivo; Bull, Peter C; Marsh, Kevin; Fowkes, Freya J I; Beeson, James G

    2016-11-01

    Antibodies to blood-stage antigens of Plasmodium falciparum play a pivotal role in human immunity to malaria. During parasite development, multiple proteins are trafficked from the intracellular parasite to the surface of P. falciparum-infected erythrocytes (IEs). However, the relative importance of different proteins as targets of acquired antibodies, and key pathways involved in trafficking major antigens remain to be clearly defined. We quantified antibodies to surface antigens among children, adults, and pregnant women from different malaria-exposed regions. We quantified the importance of antigens as antibody targets using genetically engineered P. falciparum with modified surface antigen expression. Genetic deletion of the trafficking protein skeleton-binding protein-1 (SBP1), which is involved in trafficking the surface antigen PfEMP1, led to a dramatic reduction in antibody recognition of IEs and the ability of human antibodies to promote opsonic phagocytosis of IEs, a key mechanism of parasite clearance. The great majority of antibody epitopes on the IE surface were SBP1-dependent. This was demonstrated using parasite isolates with different genetic or phenotypic backgrounds, and among antibodies from children, adults, and pregnant women in different populations. Comparisons of antibody reactivity to parasite isolates with SBP1 deletion or inhibited PfEMP1 expression suggest that PfEMP1 is the dominant target of acquired human antibodies, and that other P. falciparum IE surface proteins are minor targets. These results establish SBP1 as part of a critical pathway for the trafficking of major surface antigens targeted by human immunity, and have key implications for vaccine development, and quantifying immunity in populations.

  2. Major role for carbohydrate epitopes preferentially recognized by chronically infected mice in the determination of Schistosoma mansoni schistosomulum surface antigenicity

    International Nuclear Information System (INIS)

    Omer-ali, P.; Magee, A.I.; Kelly, C.; Simpson, A.J.G.

    1986-01-01

    A radioimmunoassay that makes use of whole Schistosomula and 125 I-labeled protein A has been used to characterize and to quantify the binding of antisera to the surface of 3 hr mechanically transformed schistosomula of Schistosoma mansoni. This technique facilitates the determination of epitopes on the schistosomula in addition to those detected by surface labeling and immunoprecipitation. By using this technique, it has been demonstrated that there is a much greater binding to the parasite surface of antibodies from chronically infected mice (CMS) than of antibodies from mice infected with highly irradiated cercariae (VMS), and CMS recognizes epitopes that VMS does not. Treatment of the surface of the schistosomula with trifluoromethanesulphonic acid and sodium metaperiodate has suggested that the discrepancy of the binding between the two sera is due to the recognition of a large number of additional epitopes by CMS, which are carbohydrate in nature. Some of the carbohydrate epitopes are expressed on the previously described surface glycoprotein antigens of M/sub r/ 200,000, 38,000, and 17,000

  3. A vaccine prepared from the 22 nm particles of surface hepatitis B antigen (HBsAg)

    International Nuclear Information System (INIS)

    Karelin, V.P.; Babaeva, E.E.; Gubenko, E.F.; Kaulen, D.K.; Zhdanov, V.M.

    1980-01-01

    A method for obtaining a subunit inactivated vaccine preparation from the 22-nm particles of HBsAg is proposed. For inactivation of the residual infectious hepatitis B virus (HBV) the preparations were successively treated with 1% sodium dodecyl sulfate (SDS) and nucleases. In addition, thermal denaturation and ultraviolet irradiation of HBV DNA were used. As a control the biologic activity of a reference virus (SV40) was tested after the same treatment. The effectiveness of DNA inactivation was monitored by adding 3H-thymidine labeled reference virus to the vaccine preparations. The purified and inactivated HBsAg was adsorbed on Al2O3. Antigenicity was calculated on the basis of the determination of antibody in guinea pigs immunized with various doses of the vaccine, and the release of 125 I- HBsAg from blood and kidneys in immunized and control mice was analyzed. Possible methods of inactivation and control of HBV vaccine is discussed

  4. Recombinant Forms of Leishmania amazonensis Excreted/Secreted Promastigote Surface Antigen (PSA) Induce Protective Immune Responses in Dogs

    Science.gov (United States)

    Petitdidier, Elodie; Pagniez, Julie; Papierok, Gérard; Vincendeau, Philippe; Lemesre, Jean-Loup; Bras-Gonçalves, Rachel

    2016-01-01

    Preventive vaccination is a highly promising strategy for interrupting leishmaniasis transmission that can, additionally, contribute to elimination. A vaccine formulation based on naturally excreted secreted (ES) antigens was prepared from L. infantum promastigote culture supernatant. This vaccine achieved successful results in Phase III trials and was licensed and marketed as CaniLeish. We recently showed that newly identified ES promastigote surface antigen (PSA), from both viable promastigotes and axenically-grown amastigotes, represented the major constituent and the highly immunogenic antigen of L. infantum and L. amazonensis ES products. We report here that three immunizations with either the recombinant ES LaPSA-38S (rPSA) or its carboxy terminal part LaPSA-12S (Cter-rPSA), combined with QA-21 as adjuvant, confer high levels of protection in naive L. infantum-infected Beagle dogs, as checked by bone marrow parasite absence in respectively 78.8% and 80% of vaccinated dogs at 6 months post-challenge. The parasite burden in infected vaccinated dogs was significantly reduced compared to placebo group, as measured by q-PCR. Moreover, our results reveal humoral and cellular immune response clear-cut differences between vaccinated and control dogs. An early increase in specific IgG2 antibodies was observed in rPSA/QA-21- and Cter-rPSA/QA-21-immunized dogs only. They were found functionally active in vitro and were highly correlated with vaccine protection. In vaccinated protected dogs, IFN-γ and NO productions, as well as anti-leishmanial macrophage activity, were increased. These data strongly suggest that ES PSA or its carboxy-terminal part, in recombinant forms, induce protection in a canine model of zoonotic visceral leishmaniasis by inducing a Th1-dominant immune response and an appropriate specific antibody response. These data suggest that they could be considered as important active components in vaccine candidates. PMID:27223609

  5. Recombinant Forms of Leishmania amazonensis Excreted/Secreted Promastigote Surface Antigen (PSA) Induce Protective Immune Responses in Dogs.

    Science.gov (United States)

    Petitdidier, Elodie; Pagniez, Julie; Papierok, Gérard; Vincendeau, Philippe; Lemesre, Jean-Loup; Bras-Gonçalves, Rachel

    2016-05-01

    Preventive vaccination is a highly promising strategy for interrupting leishmaniasis transmission that can, additionally, contribute to elimination. A vaccine formulation based on naturally excreted secreted (ES) antigens was prepared from L. infantum promastigote culture supernatant. This vaccine achieved successful results in Phase III trials and was licensed and marketed as CaniLeish. We recently showed that newly identified ES promastigote surface antigen (PSA), from both viable promastigotes and axenically-grown amastigotes, represented the major constituent and the highly immunogenic antigen of L. infantum and L. amazonensis ES products. We report here that three immunizations with either the recombinant ES LaPSA-38S (rPSA) or its carboxy terminal part LaPSA-12S (Cter-rPSA), combined with QA-21 as adjuvant, confer high levels of protection in naive L. infantum-infected Beagle dogs, as checked by bone marrow parasite absence in respectively 78.8% and 80% of vaccinated dogs at 6 months post-challenge. The parasite burden in infected vaccinated dogs was significantly reduced compared to placebo group, as measured by q-PCR. Moreover, our results reveal humoral and cellular immune response clear-cut differences between vaccinated and control dogs. An early increase in specific IgG2 antibodies was observed in rPSA/QA-21- and Cter-rPSA/QA-21-immunized dogs only. They were found functionally active in vitro and were highly correlated with vaccine protection. In vaccinated protected dogs, IFN-γ and NO productions, as well as anti-leishmanial macrophage activity, were increased. These data strongly suggest that ES PSA or its carboxy-terminal part, in recombinant forms, induce protection in a canine model of zoonotic visceral leishmaniasis by inducing a Th1-dominant immune response and an appropriate specific antibody response. These data suggest that they could be considered as important active components in vaccine candidates.

  6. Recombinant Forms of Leishmania amazonensis Excreted/Secreted Promastigote Surface Antigen (PSA Induce Protective Immune Responses in Dogs.

    Directory of Open Access Journals (Sweden)

    Elodie Petitdidier

    2016-05-01

    Full Text Available Preventive vaccination is a highly promising strategy for interrupting leishmaniasis transmission that can, additionally, contribute to elimination. A vaccine formulation based on naturally excreted secreted (ES antigens was prepared from L. infantum promastigote culture supernatant. This vaccine achieved successful results in Phase III trials and was licensed and marketed as CaniLeish. We recently showed that newly identified ES promastigote surface antigen (PSA, from both viable promastigotes and axenically-grown amastigotes, represented the major constituent and the highly immunogenic antigen of L. infantum and L. amazonensis ES products. We report here that three immunizations with either the recombinant ES LaPSA-38S (rPSA or its carboxy terminal part LaPSA-12S (Cter-rPSA, combined with QA-21 as adjuvant, confer high levels of protection in naive L. infantum-infected Beagle dogs, as checked by bone marrow parasite absence in respectively 78.8% and 80% of vaccinated dogs at 6 months post-challenge. The parasite burden in infected vaccinated dogs was significantly reduced compared to placebo group, as measured by q-PCR. Moreover, our results reveal humoral and cellular immune response clear-cut differences between vaccinated and control dogs. An early increase in specific IgG2 antibodies was observed in rPSA/QA-21- and Cter-rPSA/QA-21-immunized dogs only. They were found functionally active in vitro and were highly correlated with vaccine protection. In vaccinated protected dogs, IFN-γ and NO productions, as well as anti-leishmanial macrophage activity, were increased. These data strongly suggest that ES PSA or its carboxy-terminal part, in recombinant forms, induce protection in a canine model of zoonotic visceral leishmaniasis by inducing a Th1-dominant immune response and an appropriate specific antibody response. These data suggest that they could be considered as important active components in vaccine candidates.

  7. Optimized transitory ectopic expression of promastigote surface antigen protein in Nicotiana benthamiana, a potential anti-leishmaniasis vaccine candidate.

    Science.gov (United States)

    Lacombe, Séverine; Bangratz, Martine; Brizard, Jean-Paul; Petitdidier, Elodie; Pagniez, Julie; Sérémé, Drissa; Lemesre, Jean-Loup; Brugidou, Christophe

    2018-01-01

    In recent years, plants have been shown to be an efficient alternative expression system for high-value pharmaceuticals such as vaccines. However, constitutive expression of recombinant protein remains uncertain on their level of production and biological activity. To overcome these problems, transitory expression systems have been developed. Here, a series of experiments were performed to determine the most effective conditions to enhance vaccine antigen transient accumulation in Nicotiana benthamiana leaves using the promastigote surface antigen (PSA) from the parasitic protozoan Leishmania infantum. This protein has been previously identified as the major antigen of a licensed canine anti-leishmaniasis vaccine. The classical prokaryote Escherichia coli biosystem failed in accumulating PSA. Consequently, the standard plant system based on N. benthamiana has been optimized for the production of putatively active PSA. First, the RNA silencing defense mechanism set up by the plant against PSA ectopic expression was abolished by using three viral suppressors acting at different steps of the RNA silencing pathway. Then, we demonstrated that the signal peptide at the N-terminal side of the PSA is required for its accumulation. The PSA ER signaling and retention with the PSA signal peptide and the KDEL motif, respectively were optimized to significantly increase its accumulation. Finally, we demonstrate that the production of recombinant PSA in N. benthamiana leaves allows the conservation of its immunogenic property. These approaches demonstrate that based on these optimizations, plant based systems can be used to effectively produce the biological active PSA protein. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  8. Immunogenicity of a fusion protein comprising coli surface antigen 3 and labile B subunit of enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Alerasol, Masoome; Mousavi Gargari, Seyed Latif; Nazarian, Shahram; Bagheri, Samane

    2014-01-01

    Enterotoxigenic Escherichia coli (ETEC) strains are the major causes of diarrheal disease in humans and animals. Colonization factors and enterotoxins are the major virulence factors in ETEC pathogenesis. For the broad-spectrum protection against ETEC, one could focus on colonization factors and non-toxic heat labile as a vaccine candidate. A fusion protein is composed of a major fimbrial subunit of coli surface antigen 3, and the heat-labile B subunit (LTB) was constructed as a chimeric immunogen. For optimum level expression of protein, the gene was synthesized with codon bias of E. coli. Also, recombinant protein was expressed in E. coli BL21DE3. ELISA and Western tests were carried out for determination of antigen and specificity of antibody raised against recombinant protein in animals. The anti-toxicity and anti-adherence properties of the immune sera against ETEC were also evaluated. Immunological analyses showed the production of high titer of specific antibody in immunized mice. The built-in LTB retains native toxin properties which were approved by GM1 binding assay. Pre-treatment of the ETEC cells with anti-sera significantly decreased their adhesion to Caco-2 cells. The results indicated the efficacy of the recombinant chimeric protein as an effective immunogen inducing strong humoral response. The designated chimer would be an interesting prototype for a vaccine and worthy of further investigation.

  9. A self-amplified transistor immunosensor under dual gate operation: highly sensitive detection of hepatitis B surface antigen

    Science.gov (United States)

    Lee, I.-K.; Jeun, M.; Jang, H.-J.; Cho, W.-J.; Lee, K. H.

    2015-10-01

    Ion-sensitive field-effect transistors (ISFETs), although they have attracted considerable attention as effective immunosensors, have still not been adopted for practical applications owing to several problems: (1) the poor sensitivity caused by the short Debye screening length in media with high ion concentration, (2) time-consuming preconditioning processes for achieving the highly-diluted media, and (3) the low durability caused by undesirable ions such as sodium chloride in the media. Here, we propose a highly sensitive immunosensor based on a self-amplified transistor under dual gate operation (immuno-DG ISFET) for the detection of hepatitis B surface antigen. To address the challenges in current ISFET-based immunosensors, we have enhanced the sensitivity of an immunosensor by precisely tailoring the nanostructure of the transistor. In the pH sensing test, the immuno-DG ISFET showed superior sensitivity (2085.53 mV per pH) to both standard ISFET under single gate operation (58.88 mV per pH) and DG ISFET with a non-tailored transistor (381.14 mV per pH). Moreover, concerning the detection of hepatitis B surface antigens (HBsAg) using the immuno-DG ISFET, we have successfully detected trace amounts of HBsAg (22.5 fg mL-1) in a non-diluted 1× PBS medium with a high sensitivity of 690 mV. Our results demonstrate that the proposed immuno-DG ISFET can be a biosensor platform for practical use in the diagnosis of various diseases.Ion-sensitive field-effect transistors (ISFETs), although they have attracted considerable attention as effective immunosensors, have still not been adopted for practical applications owing to several problems: (1) the poor sensitivity caused by the short Debye screening length in media with high ion concentration, (2) time-consuming preconditioning processes for achieving the highly-diluted media, and (3) the low durability caused by undesirable ions such as sodium chloride in the media. Here, we propose a highly sensitive immunosensor

  10. Genomic Characterization of Variable Surface Antigens Reveals a Telomere Position Effect as a Prerequisite for RNA Interference-Mediated Silencing in Paramecium tetraurelia

    Science.gov (United States)

    Baranasic, Damir; Oppermann, Timo; Cheaib, Miriam; Cullum, John; Schmidt, Helmut

    2014-01-01

    ABSTRACT Antigenic or phenotypic variation is a widespread phenomenon of expression of variable surface protein coats on eukaryotic microbes. To clarify the mechanism behind mutually exclusive gene expression, we characterized the genetic properties of the surface antigen multigene family in the ciliate Paramecium tetraurelia and the epigenetic factors controlling expression and silencing. Genome analysis indicated that the multigene family consists of intrachromosomal and subtelomeric genes; both classes apparently derive from different gene duplication events: whole-genome and intrachromosomal duplication. Expression analysis provides evidence for telomere position effects, because only subtelomeric genes follow mutually exclusive transcription. Microarray analysis of cultures deficient in Rdr3, an RNA-dependent RNA polymerase, in comparison to serotype-pure wild-type cultures, shows cotranscription of a subset of subtelomeric genes, indicating that the telomere position effect is due to a selective occurrence of Rdr3-mediated silencing in subtelomeric regions. We present a model of surface antigen evolution by intrachromosomal gene duplication involving the maintenance of positive selection of structurally relevant regions. Further analysis of chromosome heterogeneity shows that alternative telomere addition regions clearly affect transcription of closely related genes. Consequently, chromosome fragmentation appears to be of crucial importance for surface antigen expression and evolution. Our data suggest that RNAi-mediated control of this genetic network by trans-acting RNAs allows rapid epigenetic adaptation by phenotypic variation in combination with long-term genetic adaptation by Darwinian evolution of antigen genes. PMID:25389173

  11. Antibodies to variable Plasmodium falciparum-infected erythrocyte surface antigens are associated with protection from novel malaria infections

    DEFF Research Database (Denmark)

    Giha, H A; Staalsoe, T; Dodoo, D

    2000-01-01

    is maintained at low densities. Here, we test the hypothesis that the presence or absence of antibodies against variant antigens on the surface of P. falciparum-infected erythrocytes protect individuals against some infectious challenges and render them susceptible to others. Plasma collected in Daraweesh......, eastern Sudan, before and after the malaria season from individuals who had (susceptible) or did not have malaria (protected) during the season, were tested for reactivity against variant antigens on the surface of nine parasite isolates by flow cytometry. Both protected and susceptible individuals...... susceptible and protected individuals. Together, the results indicate that pre-existing anti-PfEMP1 antibodies can reduce the risk of contracting clinical malaria when challenged by novel parasite clones expressing homologous, but not heterologous variable surface antigens. The results also confirm...

  12. Functional and structural changes in human erythrocyte surface after irradiation by UV waves of various wavelengths. Report 1. Expression of ABO and rhesus system antigen

    Energy Technology Data Exchange (ETDEWEB)

    Samoylova, K.A.; Klimova, K.N.; Priezzheva, L.S.; Artsishevskaya, R.A.

    1983-12-01

    To determine whether shortwave UV (SUV) radiation causes changes in the external surface of human erythrocytes, modifying the expression of the ABO and Rh system antigens known to be related to the surface of the cells, work was performed on erythrocytes in a structurally prepared erythrocyte mass from the blood of 23 donors stabilized by glugicir or heparin. Three series of experiments were performed: on isolated erythrocytes, before irradiation thrice washed to remove plasma with isotonic NaCl 0.9% and resuspended at 5 x 10/sup 7/ cells per mililiter; on erythrocytes diluted to 5 x 10/sup 7/ cells per mililiter; and on erythrocytes on the undiluted erythrocyte mass about 7.5 x 10/sup 9/ cells per mililiter. SUV radiation at 254 nm was used at a power of 4.1 W/m/sup 2/ for 1 to 60 minutes. The agglutinating activity of the ABO and Rh antigens was then studied. Two to three hours after exposure to 248, 620, 1240 and 2480 J/m/sup 2/, the degree of hemolysis of isolated erythrocytes increased by 5,10,18 and 28%. Changes were also observed in agglutinating activity of ABO antigens. The agglutinating activity of A and B antigens increased by an average factor of 2 - H antigens by a factor of 4. SUV radiation did not cause any reliable activation of the Rh antigen. 14 references.

  13. Variant surface antigen-specific IgG and protection against clinical consequences of pregnancy-associated Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Staalsoe, Trine; Shulman, Caroline E; Bulmer, Judith N

    2004-01-01

    BACKGROUND: Pregnancy-associated malaria caused by Plasmodium falciparum adherence to chondroitin sulfate A in the placental intervillous space is a major cause of low birthweight and maternal anaemia in areas of endemic P falciparum transmission. Adhesion-blocking antibodies that specifically...... recognise parasite-encoded variant surface antigens (VSA) are associated with resistance to pregnancy-associated malaria. We looked for a possible relation between VSA-specific antibody concentrations, placental infection, and protection from low birthweight and maternal anaemia. METHODS: We used flow...... cytometry to measure VSA-specific IgG concentrations in plasma samples taken during child birth from 477 Kenyan women selected from a cohort of 910 women on the basis of HIV-1 status, gravidity, and placental histology. We measured VSA expressed by one placental P falciparum isolate and two isolates...

  14. [Possible Involvement of Surface Antigen Protein 2 in the Morphological Transition and Biofilm Formation of Candida albicans].

    Science.gov (United States)

    Okamoto-Shibayama, Kazuko; Kikuchi, Yuichiro; Kokubu, Eitoyo; Ishihara, Kazuyuki

    2017-01-01

    Surface antigen protein 2 (Csa2) is a member of the Candida albicans Common in Fungal Extracellular Membranes (CFEM) protein superfamily. We previously established its role in iron acquisition in C. albicans. However, the other roles of Csa2 remain unknown. Here, we compared growth, morphological transition, and biofilm formation among wild-type, Csa2-mutant, and complemented strains of C. albicans. Deletion of the Csa2 gene resulted in smaller and reduced colony growth, significant attenuation of the dimorphic transition under serum-inducing conditions, and reduced biofilm formation; complementation restored these levels to those of the wild-type. Our findings demonstrated that Csa2 participated in yeast-to-hyphae morphological switching under serum-inducing conditions and contributed to the biofilm formation of C. albicans. This work, therefore, provides novel insights into the potential roles of Csa2 in virulence of C. albicans.

  15. Impaired cell surface expression of HLA-B antigens on mesenchymal stem cells and muscle cell progenitors

    DEFF Research Database (Denmark)

    Isa, Adiba; Nehlin, Jan; Sabir, Hardee Jawad

    2010-01-01

    HLA class-I expression is weak in embryonic stem cells but increases rapidly during lineage progression. It is unknown whether all three classical HLA class-I antigens follow the same developmental program. In the present study, we investigated allele-specific expression of HLA-A, -B, and -C...... at the mRNA and protein levels on human mesenchymal stem cells from bone marrow and adipose tissue as well as striated muscle satellite cells and lymphocytes. Using multicolour flow cytometry, we found high cell surface expression of HLA-A on all stem cells and PBMC examined. Surprisingly, HLA-B was either...... undetectable or very weakly expressed on all stem cells protecting them from complement-dependent cytotoxicity (CDC) using relevant human anti-B and anti-Cw sera. IFNgamma stimulation for 48-72 h was required to induce full HLA-B protein expression. Quantitative real-time RT-PCR showed that IFNgamma induced...

  16. Seroprevalence and risk factors of hepatitis B virus surface antigen among the workers in a garment factory

    Directory of Open Access Journals (Sweden)

    Mohammad Mizanur Rahman

    2017-11-01

    Full Text Available The purpose of this study is to find out the prevalence of seropositivity and risk factors associated with hepatitis B virus infection. A total of 2,737 readymade garment workers were initially screened after getting departmental as well as the individuals consent and simultaneously a questionnaire was filled up by the field research assistants to assess the risk factors. Initially 59 cases were found positive for hepatitis B virus surface antigen (HBsAg by immunochromato-graphic test. Enzyme linked immunosorbant technique was then applied to the screened positive HBsAg individuals and four cases turned out as negative and therefore a total of 55  HBsAg positive cases were detected in this factory. Statistically significant risk factors associated with HBsAg positivity were jaundice, history of previous surgery and accident, needle stick injuries and unsafe injections. This study concludes that the seropositivity found garment workers is similar to the general population of Bangladesh.

  17. Variant surface antigen-specific IgG and protection against clinical consequences of pregnancy-associated Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Staalsoe, Trine; Shulman, Caroline E; Bulmer, Judith N

    2004-01-01

    BACKGROUND: Pregnancy-associated malaria caused by Plasmodium falciparum adherence to chondroitin sulfate A in the placental intervillous space is a major cause of low birthweight and maternal anaemia in areas of endemic P falciparum transmission. Adhesion-blocking antibodies that specifically...... recognise parasite-encoded variant surface antigens (VSA) are associated with resistance to pregnancy-associated malaria. We looked for a possible relation between VSA-specific antibody concentrations, placental infection, and protection from low birthweight and maternal anaemia. METHODS: We used flow...... selected or not selected for chondroitin sulfate A adhesiveness in-vitro. FINDINGS: Concentrations of plasma IgG specific for VSA, expressed by chondroitin sulfate A-adhering parasites (VSA in pregnancy-associated malaria or vsa-pam), increased with gravidity and were associated with placental histological...

  18. Evaluation of hepatitis B surface antigen and hepatitis B virus-DNA results in postmortem plasma specimens

    Directory of Open Access Journals (Sweden)

    Nihan Ziyade

    2015-03-01

    Full Text Available Objective: To assess the presence of hepatitis B surface antigen, one of the serologic markers of hepatitis B virus (HBV infection, in postmortem blood samples from autopsy cases using ELISA, and to compare the results with those obtained by PCR, which is the gold standard method in assessing HBV infection. Methods: The HBV test results of the blood samples from 880 autopsy cases determined in our laboratory, were retrospectively studied. Results: When compared with the gold standard method PCR, the sensitivity and specificity of postmortem ELISA were 100% and 84.1%, respectively. Conclusions: The increasingly used molecular diagnostic methods, such as PCR, should be used in cases where serological tests remain insufficient.We think that prospective studies on the comparison of ELISA and PCR assessment of postmortem blood samples with larger material should be carried out.

  19. Multiplex flow cytometry barcoding and antibody arrays identify surface antigen profiles of primary and metastatic colon cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Kumar Sukhdeo

    Full Text Available Colon cancer is a deadly disease affecting millions of people worldwide. Current treatment challenges include management of disease burden as well as improvements in detection and targeting of tumor cells. To identify disease state-specific surface antigen signatures, we combined fluorescent cell barcoding with high-throughput flow cytometric profiling of primary and metastatic colon cancer lines (SW480, SW620, and HCT116. Our multiplexed technique offers improvements over conventional methods by permitting the simultaneous and rapid screening of cancer cells with reduced effort and cost. The method uses a protein-level analysis with commercially available antibodies on live cells with intact epitopes to detect potential tumor-specific targets that can be further investigated for their clinical utility. Multiplexed antibody arrays can easily be applied to other tumor types or pathologies for discovery-based approaches to target identification.

  20. Ionizing radiation modulates the surface expression of human leukocyte antigen-G in a human melanoma cell line

    Energy Technology Data Exchange (ETDEWEB)

    Michelin, S.; Gallegos, C.E.; Dubner, D. [Radiopathology Laboratory, Nuclear Regulatory Authority, Buenos Aires (Argentina); Favier, B.; Carosella, E.D. [CEA, I2BM, Hopital Saint-Louis, IUH, Service de Recherches en Hemato-Immunologie, Paris (France)

    2009-07-01

    Human leukocyte antigen G (HLA-G) is a nonclassical HLA class I molecule involved in fetus protection from the maternal immune system, transplant tolerance, and viral and tumoral immune escape. Tumor-specific HLA-G expression has been described for a wide variety of malignancies, including melanomas. The aim of this study was to evaluate whether ionizing radiation (IR) could modulate the surface expression of HLA-G1 in a human melanoma cell line that expresses endogenously membrane-bound HLA-G1. For this purpose, cells were exposed to increasing doses of {gamma}-irradiation (0-20 Gy) and HLA-G1 levels at the plasma membrane were analyzed at different times postirradiation by flow cytometry. HLA-G total expression and the presence of the soluble form of HLA-G1 (sHLA-G1) in the culture medium of irradiated cells were also evaluated. IR was capable of down regulating cell surface and total HLA-G levels, with a concomitant increase of sHLA-G1 in the medium. These results could indicate that {gamma}-irradiation decreases HLA-G1 surface levels by enhancing the proteolytic cleavage of this molecule. (authors)

  1. Cloning of a cDNA encoding a surface antigen of Schistosoma mansoni schistosomula recognized by sera of vassinated mice

    International Nuclear Information System (INIS)

    Dalton, J.P.; Tom, T.D.; Strand, M.

    1987-01-01

    Spleen cells of mice vaccinated with radiation-attenuated Schistosoma mansoni cercariae were used to produce monoclonal antibodies directed against newly transformed schistosomular surface antigens. One of these monoclonal antibodies recognized a polypeptide of 18 kDa. Binding was measured by radioimmunoassay. This glycoprotein was purified by monoclonal antibody immunoaffinity chromatography and a polyclonal antiserum was prepared against it. Immunofluorescence assays showed that the polyclonal antiserum bound to the surface of newly transformed schistosomula and lung-stage organisms but not to the surface of liver-stage and adult worms. Using this polyclonal antiserum we isolated recombinant clones from an adult worm cDNA expression library constructed in λgt11. Clone 654.2 contained an insert of 0.52 kilobase and hybridized to a 1.2-kilobase mRNA species from adult worms. Most importantly, clone 654.2 produced a fusion protein of 125 kDa that was reactive with sera of vaccinated mice that are capable of transferring resistance. This result encourages future vaccination trials with the fusion protein

  2. Assessing stability and assembly of the hepatitis B surface antigen into virus-like particles during down-stream processing.

    Science.gov (United States)

    Zahid, Maria; Lünsdorf, Heinrich; Rinas, Ursula

    2015-07-17

    The hepatitis B surface antigen (HBsAg) is a recombinant protein-based vaccine being able to form virus-like particles (VLPs). HBsAg is mainly produced using yeast-based expression systems, however, recent results strongly suggest that VLPs are not formed within the yeast cells during the cultivation but are formed in a gradual manner during the following down-stream procedures. VLPs are also not detectable during the first down-stream steps including mechanical and EDTA/detergent-assisted cell destruction. Moreover, VLPs are not detectable in the cell lysate treated with polyethylene glycol and colloidal silica. The first VLP resembling structures appear after elution of HBsAg from colloidal silica to which it binds through hydrophobic interaction. These first VLP resembling structures are non-symmetrical as well as heterodisperse and exhibit a high tendency toward cluster formation presumably because of surface exposed hydrophobic patches. More symmetrical and monodisperse VLPs appear after the following ion-exchange and size-exclusion chromatography most likely as the result of buffer changes during these purification steps (toward more neutral pH and less salt). Final treatment of the VLPs with the denaturant KSCN at moderate concentrations with following KSCN removal by dialysis does not cause unfolding and VLP disassembly but results in a re- and fine-structuring of the VLP surface topology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. A new technique to detect antibody-antigen reaction (biological interactions) on a localized surface plasmon resonance (LSPR) based nano ripple gold chip

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, Iram, E-mail: iiram.qau@gmail.com [Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Widger, William, E-mail: widger@uh.edu [Department of Biology and Biochemistry and Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Chu, Wei-Kan, E-mail: wkchu@uh.edu [Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States)

    2017-07-31

    Highlights: • The nano ripple LSPR chip has monolayer molecule-coating sensitivity and specific selectivity. • Gold nano-ripple sensing chip is a low cost, and a label-free method for detecting the antibody-antigen reaction. • The plasmonic resonance shift depends upon the concentration of the biomolecules attached on the surface of the nano ripple pattern. - Abstract: We demonstrate that the gold nano-ripple localized surface plasmon resonance (LSPR) chip is a low cost and a label-free method for detecting the presence of an antigen. A uniform stable layer of an antibody was coated on the surface of a nano-ripple gold pattern chip followed by the addition of different concentrations of the antigen. A red shift was observed in the LSPR spectral peak caused by the change in the local refractive index in the vicinity of the nanostructure. The LSPR chip was fabricated using oblique gas cluster ion beam (GCIB) irradiation. The plasmon-resonance intensity of the scattered light was measured by a simple optical spectroscope. The gold nano ripple chip shows monolayer scale sensitivity and high selectivity. The LSPR substrate was used to detect antibody-antigen reaction of rabbit X-DENTT antibody and DENTT blocking peptide (antigen).

  4. Driving forces for the adsorption of a His-tag Chagas antigen. A rational approach to design bio-functional surfaces.

    Science.gov (United States)

    Valenti, Laura E; Smania, Andrea M; De Pauli, Carlos P; Giacomelli, Carla E

    2013-12-01

    In order to rationally design a bio-functional surface based on the adsorption of a His-tag antigen, three requirements have to be considered: the bio-recognition element, the driving forces for the adsorption process and the detection mode of the bio-recognition event. This work is focused on the study of the adsorption mechanism of the His-tag H49 Chagas antigen on Ni(II) modified substrates. In order to construct the bio-functional surface, the gen of the H49 Chagas antigen was modified to incorporate His6 moiety at the N-terminal (His6-H49). Then, its physical adsorption and bio-affinity interaction with the solid substrate was studied by reflectometry. Besides His-Ni(II) bio-affinity interactions, His6-H49 was also physically adsorbed on Ni(II) modified substrates, leading to randomly oriented antigens. These loosely attached bio-molecules were partially removed using conditions of electrostatic repulsion. On the other hand, bio-affinity interactions, resulting in site-oriented molecules on the substrate, were only removable by specific competitors for Ni(II) surface sites. Finally, the surface bio-activity was determined from the peak separations of voltammetry waves due to the change of the electron transfer kinetics of a redox probe through the bio-functional surface (working electrode). Copyright © 2013 Elsevier B.V. All rights reserved.

  5. The PSA-2 glycoprotein complex of Leishmania major is a glycosylphosphatidylinositol-linked promastigote surface antigen.

    Science.gov (United States)

    Murray, P J; Spithill, T W; Handman, E

    1989-12-15

    Polyclonal rabbit antiserum to the Triton X-114 phase material of Leishmania major, which comprises the surface and internal integral membrane proteins of the parasite, was used to screen a lambda gt11 genomic expression library. A recombinant clone producing a Mr 123,000 beta-galactosidase fusion protein was isolated. Antibodies affinity-purified on this fusion protein recognized a complex of three surface-oriented proteins of promastigotes of L. major of Mr 94,000, 90,000, and 80,000 that we have termed the promastigote surface Ag 2 (PSA-2) complex. The DNA sequence of the insert in this clone predicted the 3' end of an open reading frame encoding a hydrophobic C-terminus. The inferred C-terminal sequence was suggestive of a glycosylphosphatidyl-inositol membrane anchoring mechanism. Phosphatidylinositol-specific phospholipase C treatment of the native PSA-2 proteins caused a shift in their electrophoretic mobility with an apparent reduction in the molecular weight of the PSA-2 complex. After phospholipase C treatment these proteins also displayed the cryptic cross-reacting determinant recognized by antibodies to the Trypanosoma brucei variant surface Ag. Moreover, PSA-2, which previously partitioned in the detergent phase after Triton X-114 phase separation, became water-soluble after phospholipase C treatment. Immunoprecipitation of the PSA-2 proteins with sera directed to lectin-binding proteins indicated that these polypeptides may be differentially glycosylated. Finally, these PSA-2 proteins were recognized by sera from some patients with cutaneous leishmaniasis.

  6. Quantitative analysis of rat Ig (sub)classes binding to cell surface antigens

    International Nuclear Information System (INIS)

    Nilsson, R.; Brodin, T.; Sjoegren, H.-O.

    1982-01-01

    An indirect 125 I-labeled protein A assay for detection of cell surface-bound rat immunoglobulins is presented. The assay is quantitative and rapid and detects as little as 1 ng of cell surface-bound Ig. It discriminates between antibodies belonging to different IgG subclasses, IgM and IgA. The authors describe the production and specificity control of the reagents used and show that the test can be used for quantitative analysis. A large number of sera from untreated rats are tested to evaluate the frequency of falsely positive responses and variation due to age, sex and strain of rat. With this test it is relatively easy to quantitate the binding of classes and subclasses of rat immunoglobulins in a small volume (6 μl) of untreated serum. (Auth.)

  7. Antigen 43-mediated autotransporter display, a versatile bacterial cell surface presentation system

    DEFF Research Database (Denmark)

    Kjærgaard, Kristian; Hasman, Henrik; Schembri, Mark

    2002-01-01

    to the outer membrane and secretion through the cell envelope is contained within the protein itself. Ag43 consists of two subunits (alpha and beta), where the beta-subunit forms an integral outer membrane translocator to which the alpha-subunit is noncovalently attached. The simplicity of the Ag43 system...... makes it ideally suited as a surface display scaffold. Here we demonstrate that the Ag43 alpha-module can accommodate and display correctly folded inserts and has the ability to display entire functional protein domains, exemplified by the FimH lectin domain. The presence of heterologous cysteine...... bridges does not interfere with surface display, and Ag43 chimeras are correctly processed into alpha- and beta-modules, offering optional and easy release of the chimeric alpha-subunits. Furthermore, Ag43 can be displayed in many gram-negative bacteria. This feature is exploited for display of our...

  8. Baseline hepatitis B surface antigen quantitation can predict virologic response in entecavir-treated chronic hepatitis B patients.

    Science.gov (United States)

    Wang, Chia-Chi; Tseng, Tai-Chung; Wang, Pin-Chao; Lin, Hans Hsienhong; Kao, Jia-Horng

    2014-11-01

    Several anti-viral drugs are approved for the treatment of hepatitis B virus (HBV) infection. However, whether quantitative hepatitis B surface antigen (qHBsAg) can predict the therapeutic response during long-term entecavir treatment remains unclear. Fifty-five chronic hepatitis B (CHB) patients who received entecavir for more than 2 years were enrolled. The serum qHBsAg level was measured by HBsAg II quant immunoassay. A significant decline in the qHBsAg level was defined as > 1 log reduction from baseline to 6 months of entecavir treatment. Of the 55 patients (41 males and 14 females with a mean age of 48.3 ± 11.4 years), 23 patients were positive for hepatitis B e antigen (HBeAg). The median treatment period was 34 months, and ranged from 26 months to 43 months. A total of 288 serum samples were used to determine the qHBsAg levels. At year 3 of entecavir therapy, one (1.8%) patient had HBsAg seroclearance. A high qHBsAg level was defined as greater than 10,000 IU/mL. Patients with a high baseline qHBsAg level had a lower rate of virologic response at year 1 (37.5% vs. 89.7%, p response in all patients. The baseline serum qHBsAg level can predict virologic response in entecavir-treated CHB patients. However, a significant decline in the qHBsAg level cannot predict serologic or virologic response of entecavir treatment. Copyright © 2013. Published by Elsevier B.V.

  9. Correlation between two chemiluminescence based assays for quantification of hepatitis B surface antigen in patients with chronic hepatitis B infection

    Directory of Open Access Journals (Sweden)

    E Gupta

    2015-01-01

    Full Text Available Purpose: Hepatitis B surface Antigen (HBsAg is the hallmark in diagnosing hepatitis B virus (HBV infection. In India many commercial assays are available for detection of HBsAg but very few can measure it quantitatively. The present study presents the comparative evaluation of two methods and their correlation with serum HBsAg in chronic hepatitis B (CHB patients. Materials and Methods: Consecutive patients of CHB were included and there HBsAg levels were measured by two methods: (i Elecsys, Roche Diagnostics, a qualitative assay and (ii Architect, Abbott Diagnostics, a quantitative assay. The HBV DNA was measured by real-time polymerase chain reaction (qPCR. Results: Total of 136 patients were included in the study and there was a significant overall correlation between both the assays (correlation coefficient [r] = 0.83; P < 0.001. Assays correlated well with each other across all subgroups of CHB: treatment naοve (r = 0.73; P < 0.001, n = 32, on treatment (r = 0.56; P < 0.05, n = 104, hepatitis Be (HBe antigen positive (r = 0.67; P < 0.001, n = 62 and anti-HBe positive (r = 0.61; P < 0.05, n = 74 group. On correlation with serum HBV DNA, Architect assay demonstrated good correlation (r = 0.73; P < 0.001, n = 136 as compared to the Elecsys assay (r = 0.27; P = 0.068, n = 136. Architect HBsAg QT assay (A1 also correlated well with HBV DNA in the treatment naοve group (r = 0.69; P < 0.001, n = 32. Conclusions: Our study hence proved that both the assays are comparable and a simple qualitative assay with in-house modification can be used easily for quatitation of HBsAg in clinical samples.

  10. Protective vaccination with promastigote surface antigen 2 from Leishmania major is mediated by a TH1 type of immune response.

    Science.gov (United States)

    Handman, E; Symons, F M; Baldwin, T M; Curtis, J M; Scheerlinck, J P

    1995-11-01

    Leishmania major promastigote surface antigen-2 complex (PSA-2) comprises a family of three similar but distinct polypeptides. The three PSA-2 polypeptides were purified from cultured promastigotes by a combination of detergent phase separation and monoclonal antibody affinity chromatography. Intraperitoneal vaccination of C3H/He mice with PSA-2 with Corynebacterium parvum as an adjuvant resulted in complete protection from lesion development after challenge infection with virulent L. major. Significant protection was also obtained in the genetically susceptible BALB/cH-2k and BALB/c mice. One of the PSA-2 genes was cloned and expressed in both Escherichia coli and Leishmania mexicana promastigotes. Vaccination with the recombinant PSA-2 purified from E. coli did not confer protection, in contrast to the L. mexicana-derived recombinant PSA-2, which provided excellent protection. CD4+ T cells isolated from the spleens of vaccinated mice produced large amounts of gamma interferon but no detectable interleukin 4 upon stimulation with PSA-2 in vitro. Limiting dilution analysis showed a marked increase in the precursor frequency of PSA-2-specific gamma interferon-secreting CD4+ T cells. No substantial change in precursor frequency was observed for interleukin 4-secreting T cells in the vaccinated mice. A CD4+ PSA-2 specific T-cell line generated from splenocytes of a vaccinated mouse produces a cytokine pattern consistent with a TH1 phenotype. Intravenous injection of this line into naive mice reduced significantly the parasite burden upon challenge infection. Taken together, the data suggest that vaccination with PSA-2 induces a TH1 type of immune response which protects mice from L. major infection. Moreover, a single recombinant PSA-2 polypeptide derived from a genomic clone can also vaccinate, provided that the structural form of the antigen is near native.

  11. Plasmodium falciparum parasites expressing pregnancy-specific variant surface antigens adhere strongly to the choriocarcinoma cell line BeWo

    DEFF Research Database (Denmark)

    Haase, Rikke N; Megnekou, Rosette; Lundquist, Maja

    2006-01-01

    Placenta-sequestering Plasmodium falciparum parasites causing pregnancy-associated malaria express pregnancy-specific variant surface antigens (VSA(PAM)). We report here that VSA(PAM)-expressing patient isolates adhere strongly to the choriocarcinoma cell line BeWo and that the BeWo line can...... be used to efficiently select for VSA(PAM) expression in vitro....

  12. The neural cell adhesion molecule L1 is distinct from the N-CAM related group of surface antigens BSP-2 and D2

    DEFF Research Database (Denmark)

    Faissner, A; Kruse, J; Goridis, C

    1984-01-01

    The neural cell adhesion molecule L1 and the group of N-CAM related molecules, BSP-2 and D2 antigen, are immunochemically distinct molecular species. The two groups of surface molecules are also functionally distinct entities, since inhibition of Ca2+-independent adhesion among early post-natal m...

  13. Expression of variant surface antigens by Plasmodium falciparum parasites in the peripheral blood of clinically immune pregnant women indicates ongoing placental infection

    DEFF Research Database (Denmark)

    Ofori, Michael F; Staalsoe, Trine; Bam, Victoria

    2003-01-01

    Placenta-sequestered Plasmodium falciparum parasites that cause pregnancy-associated malaria (PAM) in otherwise clinically immune women express distinct variant surface antigens (VSA(PAM)) not expressed by parasites in nonpregnant individuals. We report here that parasites from the peripheral blood...

  14. Characterization of the antigenicity of Cpl1, a surface protein of Cryptococcus neoformans var. neoformans.

    Science.gov (United States)

    Cai, Jian-Piao; Liu, Ling-Li; To, Kelvin K W; Lau, Candy C Y; Woo, Patrick C Y; Lau, Susanna K P; Guo, Yong-Hui; Ngan, Antonio H Y; Che, Xiao-Yan; Yuen, Kwok-Yung

    2015-01-01

    Cryptococcus neoformans var. neoformans is an important fungal pathogen. The capsule is a well established virulence factor and a target site for diagnostic tests. The CPL1 gene is required for capsular formation and virulence. The protein product Cpl1 has been proposed to be a secreted protein, but the characteristics of this protein have not been reported. Here we sought to characterize Cpl1. Phylogenetic analysis showed that the Cpl1 of C. neoformans var. neoformans and the Cpl1 orthologs identified in C. neoformans var. grubii and C. gattii formed a distinct cluster among related fungi; while the putative ortholog found in Trichosporon asahii was distantly related to the Cryptococcus cluster. We expressed Cpl1 abundantly as a secreted His-tagged protein in Pichia pastoris. The protein was used to immunize guinea pigs and rabbits for high titer mono-specific polyclonal antibody that was shown to be highly specific against the cell wall of C. neoformans var. neoformans and did not cross react with C. gattii, T. asahii, Aspergillus spp., Candida spp. and Penicillium spp. Using the anti-Cpl1 antibody, we detected Cpl1 protein in the fresh culture supernatant of C. neoformans var. neoformans and we showed by immunostaining that the Cpl1 protein was located on the surface. The Cpl1 protein is a specific surface protein of C. neoformans var. neoformans. © 2015 by The Mycological Society of America.

  15. The promastigote surface antigen gene family of the Leishmania parasite: differential evolution by positive selection and recombination

    OpenAIRE

    Bañuls Anne-Laure; Devault Alain

    2008-01-01

    Abstract Background PSA (promastigote surface antigen) is one of the major classes of membrane proteins present at the surface of the parasitic protozoan Leishmania. While it harbours leucine rich repeats, which are suggestive of its involvement in parasite-to-host physical interactions, its exact role is largely unknown. Furthermore, the extent of diversity of this gene family, both in copy number and sequence has not been established. Results From the newly available complete genome sequenc...

  16. Mechanisms of recurrent otitis media: importance of the immune response to bacterial surface antigens.

    Science.gov (United States)

    Murphy, T F; Yi, K

    1997-12-29

    Otitis-prone children experience recurrent episodes of otitis media due to nontypeable H. influenzae (NTHI). A protective immune response occurs following infection, but this immune response is specific for the infecting strain, leaving the child susceptible to infection by other strains of NTHI. Little is known about the mechanism by which a strain-specific antibody response occurs to nonencapsulated bacteria. To explore the mechanism by which this strain-specific response occurs, animals were inoculated with whole bacterial cells and the antibody response was studied. The antibody response was predominantly directed to a highly strain-specific, immunodominant surface loop on the major outer membrane protein. This exquisitely restricted immune response leaves the host susceptible to recurrent infections by many strains of NTHI. The ability of the bacterium to direct the host to make a strain-specific antibody response has important implications in understanding the immune response to otitis media due to NTHI and in designing strategies for vaccine development.

  17. The Leishmania promastigote surface antigen-2 (PSA-2) is specifically recognised by Th1 cells in humans with naturally acquired immunity to L. major

    DEFF Research Database (Denmark)

    Kemp, M; Handman, E; Kemp, K

    1998-01-01

    The promastigote surface antigen-2 (PSA-2) is a Leishmania parasite antigen, which can induce Th1-mediated protection against murine leishmaniasis when used as a vaccine. To evaluate PSA-2 as a human vaccine candidate the specific T-cell response to PSA-2 was characterised in individuals immune......-beta, and little interleukin-4, thereby showing a Th1 cytokine pattern. Parallel cultures showed clear Th1 and Th2 response patterns to purified protein derivative of tuberculin or tetanus toxoid, respectively. Flow cytometric analysis revealed that PSA-2 induced blastogenesis in the CD3 positive population...... and that these cells were the major source of interferon-gamma. The results show that Th1-like cells recognising PSA-2 are expanded during infection by L. major and that they maintain their Th1-like cytokine profile upon reactivation in vitro. Since immunity to cutaneous leishmaniasis is mediated by antigen...

  18. The Leishmania promastigote surface antigen-2 (PSA-2) is specifically recognised by Th1 cells in humans with naturally acquired immunity to L. major

    DEFF Research Database (Denmark)

    Kemp, M; Handman, E; Kemp, K

    1998-01-01

    The promastigote surface antigen-2 (PSA-2) is a Leishmania parasite antigen, which can induce Th1-mediated protection against murine leishmaniasis when used as a vaccine. To evaluate PSA-2 as a human vaccine candidate the specific T-cell response to PSA-2 was characterised in individuals immune...... to cutaneous leishmaniasis. Peripheral blood mononuclear cells from Sudanese individuals with a past history of self-healing cutaneous leishmaniasis proliferated vigorously in response to PSA-2 isolated from Leishmania major, whereas the antigen did not activate cells from presumably unexposed Danes....... Peripheral blood mononuclear cells from individuals with previous L. major infection had varying proliferative responses to PSA-2 derived from L. donovani promastigotes. Peripheral blood mononuclear cells activated by PSA-2 from L. major produced high amounts of interferon-gamma and tumour necrosis factor...

  19. Evolutionary structure of Plasmodium falciparum major variant surface antigen genes in South America: Implications for epidemic transmission and surveillance.

    Science.gov (United States)

    Rougeron, Virginie; Tiedje, Kathryn E; Chen, Donald S; Rask, Thomas S; Gamboa, Dionicia; Maestre, Amanda; Musset, Lise; Legrand, Eric; Noya, Oscar; Yalcindag, Erhan; Renaud, François; Prugnolle, Franck; Day, Karen P

    2017-11-01

    Strong founder effects resulting from human migration out of Africa have led to geographic variation in single nucleotide polymorphisms (SNPs) and microsatellites (MS) of the malaria parasite, Plasmodium falciparum . This is particularly striking in South America where two major founder populations of P. falciparum have been identified that are presumed to have arisen from the transatlantic slave trade. Given the importance of the major variant surface antigen of the blood stages of P. falciparum as both a virulence factor and target of immunity, we decided to investigate the population genetics of the genes encoding " Plasmodium falciparum Erythrocyte Membrane Protein 1" ( Pf EMP1) among several countries in South America, in order to evaluate the transmission patterns of malaria in this continent. Deep sequencing of the DBLα domain of var genes from 128 P. falciparum isolates from five locations in South America was completed using a 454 high throughput sequencing protocol. Striking geographic variation in var DBLα sequences, similar to that seen for SNPs and MS markers, was observed. Colombia and French Guiana had distinct var DBLα sequences, whereas Peru and Venezuela showed an admixture. The importance of such geographic variation to herd immunity and malaria vaccination is discussed.

  20. A molecular assembly system for presentation of antigens on the surface of HBc virus-like particles

    Energy Technology Data Exchange (ETDEWEB)

    Blokhina, Elena A.; Kuprianov, Victor V. [Centre ' Bioengineering' , Russian Academy of Sciences, 117312 Prosp. 60-letya Oktyabrya 7-1, Moscow (Russian Federation); Stepanova, Ludmila A.; Tsybalova, Ludmila M. [Research Institute of Influenza, Russian Federation Ministry of Health and Social Development, St. Petersburg (Russian Federation); Kiselev, Oleg I. [Research Institute of Influenza, Russian Federation Ministry of Health and Social Development, St. Petersburg (Russian Federation); GenNanotech Ltd, St. Petersburg (Russian Federation); Ravin, Nikolai V., E-mail: nravin@biengi.ac.ru [Centre ' Bioengineering' , Russian Academy of Sciences, 117312 Prosp. 60-letya Oktyabrya 7-1, Moscow (Russian Federation); GenNanotech Ltd, St. Petersburg (Russian Federation); Skryabin, Konstantin G. [Centre ' Bioengineering' , Russian Academy of Sciences, 117312 Prosp. 60-letya Oktyabrya 7-1, Moscow (Russian Federation); GenNanotech Ltd, St. Petersburg (Russian Federation)

    2013-01-20

    Hepatitis B virus-like particles, icosahedral structures formed by multiple core protein dimers, are promising immune-enhancing vaccine carriers for foreign antigens. Insertions into the surface-exposed immunodominant loop are especially immunogenic. However, the need to conserve the particulate structure to ensure high immunogenicity imposes restraints on the nature of the heterologous sequence that can be inserted. We propose a new approach to constructing HBc particles linked to the target epitopes that relies on non-covalent interactions between the epitope and pre-assembled unmodified HBc particles. Interaction was enabled by fusion of the epitope to the GSLLGRMKGA peptide, binding to the spike tips. This peptide may be used as a 'binding tag' allowing in vitro construction of HBc particles carrying the target peptide. Such virus-like particles carrying multiple copies of the extracellular domain of the M2 protein of different influenza strains appeared to be highly immunogenic and protected immunised mice against a lethal influenza challenge.

  1. Prevalence of hepatitis B virus surface antigen (HBsAg) in patients undergoing extraction at the University College Hospital, Ibadan.

    Science.gov (United States)

    Odaibo, G N; Arotiba, J T; Fasola, A O; Obiechina, A E; Olaleye, O D; Ajagbe, H A

    2003-09-01

    Hepatitis B Virus (HBV) infection and its sequelae (liver chirrhosis and hepatic carcinoma) are endemic in Africa. The risk of transmission of the infection during dental treatment is real. This study was carried out to determine the rate of Hepatits B Surface Antigen (HBsAg) as a marker of hepatitis B virus infection in patients undergoing dental extraction in order to highlight the potential risk of nosocomial transmission among the Dental Health Workers (DHW) and their patients. Three hundred (143 males and 157 females) consecutive patients requiring dental extraction who volunteered were enrolled into this study. Their ages ranged from 11 years to 95 years with a mean of 37.2 years (SD = 16.725) and a median of 36 years. The overall HBsAg infection rate was 18.3% (55/300). A higher infection rate (23.1%) occurred among the male patients compared with 14% in females (p = 0.0086). The high rate of HBV infection found among this study population suggests that Dental Surgeons in this environment have a high risk of exposure to hepatitis B virus and should be immunized at the beginning of their professional life. Universal biosafety measures should be observed strictly in all invasive procedures.

  2. Hepatitis B Vaccination Coverage and Prevalence of Hepatitis B Surface Antigen Among Children in French Polynesia, 2014.

    Science.gov (United States)

    Patel, Minal K; Le Calvez, Evelyne; Wannemuehler, Kathleen; Ségalin, Jean-Marc

    2016-06-01

    French Polynesia is considered to be moderately endemic for chronic hepatitis B virus infection, with an estimated 3% of the population having hepatitis B surface antigen (HBsAg). From 1990 to 1992, a 3-dose hepatitis B vaccination series was introduced into the routine infant immunization schedule in French Polynesia, including a birth dose (BD). In 2014, a nationally representative 2-stage cluster survey was undertaken to evaluate the impact of the vaccination program on HBsAg prevalence among school children (∼6 years of age) in Cours Préparatoire (CP). Documented vaccination data were reviewed for all eligible children; children with consent were tested for HBsAg with a rapid point-of-care test. In total, 1,660 students were identified; 1,567 (94%) had vaccination data for review and 1,196 (72%) participated in the serosurvey. Three-dose vaccination coverage was 98%, while timely BD coverage, defined as a dose administered within 24 hours of life, was 89%. Receipt of the second and third doses was often delayed, with 75% and 55% receiving a second and third dose within 1 month of the recommended age, respectively. No children tested positive for HBsAg. French Polynesia's vaccination program has achieved high coverage and an HBsAg seroprevalence of 0% (0-0.5%) among CP school children, but timeliness of vaccination could be improved. © The American Society of Tropical Medicine and Hygiene.

  3. Characterization of surface antigen protein 1 (SurA1) from Acinetobacter baumannii and its role in virulence and fitness.

    Science.gov (United States)

    Liu, Dong; Liu, Zeng-Shan; Hu, Pan; Cai, Ling; Fu, Bao-Quan; Li, Yan-Song; Lu, Shi-Ying; Liu, Nan-Nan; Ma, Xiao-Long; Chi, Dan; Chang, Jiang; Shui, Yi-Ming; Li, Zhao-Hui; Ahmad, Waqas; Zhou, Yu; Ren, Hong-Lin

    2016-04-15

    Acinetobacter baumannii is a Gram-negative bacillus that causes nosocomial infections, such as bacteremia, pneumonia, and meningitis and urinary tract and wound infections. In the present study, the surface antigen protein 1 (SurA1) gene of A. baumannii strain CCGGD201101 was identified, cloned and expressed, and then its roles in fitness and virulence were investigated. Virulence was observed in the human lung cancer cell lines A549 and HEp-2 at one week after treatment with recombinant SurA1. One isogenic SurA1 knock-out strain, GR0015, which was derived from the A. baumannii strain CCGGD201101 isolated from diseased chicks in a previous study, highlighted the effect of SurA1 on fitness and growth. Its growth rate in LB broth and killing activity in human sera were significantly decreased compared with strain CCGGD201101. In the Galleria mellonella insect model, the isogenic SurA1 knock-out strain exhibited a lower survival rate and decreased dissemination. These results suggest that SurA1 plays an important role in the fitness and virulence of A. baumannii. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Establishment of an in vivo potency assay for the recombinant hepatit is B surface antigen in monovalent and combined vaccines

    Directory of Open Access Journals (Sweden)

    Mabel Izquierdo-López

    2014-12-01

    Full Text Available In this paper the development of potency assay in animals (mice was made, with the objective of demonstrating the immunogenic power of the recombinant Hepatitis B surface antigen in monovalent and combined vaccines, produced at the Center of Genetic Engineering and Biotechnology. The potency test is a parameter in quality control and it is also a tool to demonstrate the consistency of the production process. Parameters such as duration of the test, number of animals in the test, as well as different areas for the maintenance of the animals were evaluated. The results on the applicability of the potency test, to two presentations of the vaccines; monovalent Heberbiovac HB and pentavalent liquid in one vial Heberpenta-L are shown, for which specificity studies, evaluating different vaccine lots, the behavior of linearity, and parallelism, as well as establishing quality specification of the test were performed. This assay led to the obtainment of reliable results for the vaccines evaluated, the consistent evaluation of the immunogenic power and the monitoring of different production processes.

  5. Pectinesterase Inhibitor from Jelly Fig (Ficus awkeotsang Makino Achene Inhibits Surface Antigen Expression by Human Hepatitis B Virus

    Directory of Open Access Journals (Sweden)

    Yu-Chuen Huang

    2013-01-01

    Full Text Available Pectinesterase inhibitor (PEI isolated from jelly fig (Ficus awkeotsang Makino is an edible component of a popular drink consumed in Asia. Hepatitis B virus (HBV infection is prevalent in Asia, and current treatments for HBV infection need improvement. This study aimed to evaluate the effect of PEI on the surface antigen expression by HBV (HBsAg. Human hepatoma cell lines Hep3B and Huh7 served as in vitro models for assessing the cytotoxicity and HBsAg expression. A culture of primary hepatocytes cultured from mice served as the normal counterpart. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT colorimetric assay. HBsAg expression was evaluated by measuring HBsAg secretion into the culture medium using an enzyme-linked immunosorbent assay. The results showed that PEI did not affect the viability of the human hepatoma cell lines or primary mouse hepatocytes. PEI inhibited the expression of HBsAg in hepatoma cell lines harboring endogenous (Hep3B and integrated (Huh7 HBV genomes in a concentration- and time-dependent manner, thus implicating a universal activity against HBV gene expression. In conclusion, it suggests that PEI from jelly fig inhibits the expression of human HBsAg in host cells without toxic effects on normal primary hepatocytes.

  6. Pectinesterase Inhibitor from Jelly Fig (Ficus awkeotsang Makino) Achene Inhibits Surface Antigen Expression by Human Hepatitis B Virus.

    Science.gov (United States)

    Huang, Yu-Chuen; Jiang, Chii-Ming; Chen, Yu-Jen; Chen, Yu-Yawn

    2013-01-01

    Pectinesterase inhibitor (PEI) isolated from jelly fig (Ficus awkeotsang Makino) is an edible component of a popular drink consumed in Asia. Hepatitis B virus (HBV) infection is prevalent in Asia, and current treatments for HBV infection need improvement. This study aimed to evaluate the effect of PEI on the surface antigen expression by HBV (HBsAg). Human hepatoma cell lines Hep3B and Huh7 served as in vitro models for assessing the cytotoxicity and HBsAg expression. A culture of primary hepatocytes cultured from mice served as the normal counterpart. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. HBsAg expression was evaluated by measuring HBsAg secretion into the culture medium using an enzyme-linked immunosorbent assay. The results showed that PEI did not affect the viability of the human hepatoma cell lines or primary mouse hepatocytes. PEI inhibited the expression of HBsAg in hepatoma cell lines harboring endogenous (Hep3B) and integrated (Huh7) HBV genomes in a concentration- and time-dependent manner, thus implicating a universal activity against HBV gene expression. In conclusion, it suggests that PEI from jelly fig inhibits the expression of human HBsAg in host cells without toxic effects on normal primary hepatocytes.

  7. Prevalence of Hepatitis B core antibodies with negative Hepatitis B surface antigen in dialysis and chronic kidney disease patients

    Directory of Open Access Journals (Sweden)

    Nauman Tarif

    2017-01-01

    Full Text Available Occult hepatitis B infection (OBI is a potential cause of infection transmission in patients with chronic kidney disease (CKD and dialysis-dependant patients. It is liable to be missed since the marker for OBI, hepatitis B core antibody (HBcAb, is not done routinely. We carried out a study to assess the prevalence of OBI in CKD Stage II–V or requiring renal replacement therapy. It was a cross-sectional study carried out at Fatima Memorial Hospital, Lahore, from May 2104 to May 2015. A total of 188 patients were included in this study, 124 were dialysis dependent and 64 had acute or CKD Stage II–V. About 17.55% (n = 33 of patients had isolated HBcAb positive. Nearly 33.5% (n = 63 of patients were found to have hepatitis B surface antigen positive, indicating development of immunity by exposure to virus. About 20.74% (n = 39 of patients were co-positive with HBcAb also. The prevalence of isolated HBcAb in dialysis and CKD patients is high; therefore, testing for HBcAb should be a routine part of screening in our CKD population to rule out OBI. Further confirmation with polymerase chain reaction analysis for HBV viral DNA is recommended. Considering our circumstances, a consensus statement from the hepatologists and nephrologists is needed to further plan for the management of such cases.

  8. Safety of using hepatitis B virus core antibody or surface antigen-positive donors in kidney or pancreas transplantation.

    Science.gov (United States)

    Akalin, Enver; Ames, Scott; Sehgal, Vinita; Murphy, Barbara; Bromberg, Jonathan S

    2005-06-01

    Hepatitis B virus core antibody (HBcAb) or surface antigen (HBsAg)-positive organ donors have the potential to transmit infection to transplant recipients. We investigated the safety of using HBcAb(+) or HBsAg(+) donors in kidney or pancreas transplant recipients with 1 yr lamivudine prophylaxis. While HBsAb(-) recipients of HBcAb(+) donors received prophylaxis, HBsAb(+) recipients did not. HBsAg(+) organs were only used in patients who were both HBcAb and HBsAb(+). Forty-six patients received HBcAb(+) and four received HBsAg(+) organs (47 kidney, two pancreas, and one kidney/pancreas). All but one recipient were HBsAg(-), 25 were HBsAb(+), and 19 HBcAb(+). During a median 36 months of follow-up (range 6-66 months), with 43 of a total 50 patients having at least 1 yr follow-up and were off lamivudine, and none of the patients developed hepatitis B viremia or seroconversion to HBsAg or HBsAb(+). These results suggest that HBcAb(+) or HBsAg(+) organs can be used safely in selected recipients with lamivudine prophylaxis without requiring hepatitis B immunglobulin.

  9. Prevalence of Hepatitis B core antibodies with negative Hepatitis B surface antigen in dialysis and chronic kidney disease patients.

    Science.gov (United States)

    Tarif, Nauman; Riaz, Muhammad Mohsin; Sabir, Omer; Akhter, Rizwan; Rafique, Kashif; Rizvi, Nabiha

    2017-01-01

    Occult hepatitis B infection (OBI) is a potential cause of infection transmission in patients with chronic kidney disease (CKD) and dialysis-dependant patients. It is liable to be missed since the marker for OBI, hepatitis B core antibody (HBcAb), is not done routinely. We carried out a study to assess the prevalence of OBI in CKD Stage II-V or requiring renal replacement therapy. It was a cross-sectional study carried out at Fatima Memorial Hospital, Lahore, from May 2104 to May 2015. A total of 188 patients were included in this study, 124 were dialysis dependent and 64 had acute or CKD Stage II-V. About 17.55% (n = 33) of patients had isolated HBcAb positive. Nearly 33.5% (n = 63) of patients were found to have hepatitis B surface antigen positive, indicating development of immunity by exposure to virus. About 20.74% (n = 39) of patients were co-positive with HBcAb also. The prevalence of isolated HBcAb in dialysis and CKD patients is high; therefore, testing for HBcAb should be a routine part of screening in our CKD population to rule out OBI. Further confirmation with polymerase chain reaction analysis for HBV viral DNA is recommended. Considering our circumstances, a consensus statement from the hepatologists and nephrologists is needed to further plan for the management of such cases.

  10. Nonstructural Protein 4 of Porcine Reproductive and Respiratory Syndrome Virus Modulates Cell Surface Swine Leukocyte Antigen Class I Expression by Downregulating β2-Microglobulin Transcription.

    Science.gov (United States)

    Qi, Pengfei; Liu, Ke; Wei, Jianchao; Li, Yuming; Li, Beibei; Shao, Donghua; Wu, Zhuanchang; Shi, Yuanyuan; Tong, Guangzhi; Qiu, Yafeng; Ma, Zhiyong

    2017-03-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of PRRS, which has important impacts on the pig industry. PRRSV infection results in disruption of the swine leukocyte antigen class I (SLA-I) antigen presentation pathway. In this study, highly pathogenic PRRSV (HP-PRRSV) infection inhibited transcription of the β2-microglobulin (β2M) gene ( B2M ) and reduced cellular levels of β2M, which forms a heterotrimeric complex with the SLA-I heavy chain and a variable peptide and plays a critical role in SLA-I antigen presentation. HP-PRRSV nonstructural protein 4 (Nsp4) was involved in the downregulation of β2M expression. Exogenous expression of Nsp4 downregulated β2M expression at both the mRNA and the protein level and reduced SLA-I expression on the cell surface. Nsp4 bound to the porcine B2M promoter and inhibited its transcriptional activity. Domain III of Nsp4 and the enhancer PAM element of the porcine B2M promoter were identified as essential for the interaction between Nsp4 and B2M These findings demonstrate a novel mechanism whereby HP-PRRSV may modulate the SLA-I antigen presentation pathway and provide new insights into the functions of HP-PRRSV Nsp4. IMPORTANCE PRRSV modulates the host response by disrupting the SLA-I antigen presentation pathway. We show that HP-PRRSV downregulates SLA-I expression on the cell surface via transcriptional inhibition of B2M expression by viral Nsp4. The interaction between domain III of Nsp4 and the enhancer PAM element of the porcine B2M promoter is essential for inhibiting B2M transcription. These observations reveal a novel mechanism whereby HP-PRRSV may modulate SLA-I antigen presentation and provide new insights into the functions of viral Nsp4. Copyright © 2017 American Society for Microbiology.

  11. In Vitro Variant Surface Antigen Expression in Plasmodium falciparum Parasites from a Semi-Immune Individual Is Not Correlated with Var Gene Transcription

    Science.gov (United States)

    Tschan, Serena; Flötenmeyer, Matthias; Koch, Iris; Berger, Jürgen; Kremsner, Peter; Frank, Matthias

    2016-01-01

    Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is considered to be the main variant surface antigen (VSA) of Plasmodium falciparum and is mainly localized on electron-dense knobs in the membrane of the infected erythrocyte. Switches in PfEMP1 expression provide the basis for antigenic variation and are thought to be critical for parasite persistence during chronic infections. Recently, strain transcending anti-PfEMP1 immunity has been shown to develop early in life, challenging the role of PfEMP1 in antigenic variation during chronic infections. In this work we investigate how P. falciparum achieves persistence during a chronic asymptomatic infection. The infected individual (MOA) was parasitemic for 42 days and multilocus var gene genotyping showed persistence of the same parasite population throughout the infection. Parasites from the beginning of the infection were adapted to tissue culture and cloned by limiting dilution. Flow cytometry using convalescent serum detected a variable surface recognition signal on isogenic clonal parasites. Quantitative real-time PCR with a field isolate specific var gene primer set showed that the surface recognition signal was not correlated with transcription of individual var genes. Strain transcending anti-PfEMP1 immunity of the convalescent serum was demonstrated with CD36 selected and PfEMP1 knock-down NF54 clones. In contrast, knock-down of PfEMP1 did not have an effect on the antibody recognition signal in MOA clones. Trypsinisation of the membrane surface proteins abolished the surface recognition signal and immune electron microscopy revealed that antibodies from the convalescent serum bound to membrane areas without knobs and with knobs. Together the data indicate that PfEMP1 is not the main variable surface antigen during a chronic infection and suggest a role for trypsin sensitive non-PfEMP1 VSAs for parasite persistence in chronic infections. PMID:27907004

  12. In Vitro Evaluation of a Soluble Leishmania Promastigote Surface Antigen as a Potential Vaccine Candidate against Human Leishmaniasis

    Science.gov (United States)

    Bahi-Jaber, Narges; Petitdidier, Elodie; Markikou-Ouni, Wafa; Aoun, Karim; Moreno, Javier; Carrillo, Eugenia; Salotra, Poonam; Kaushal, Himanshu; Negi, Narender Singh; Arevalo, Jorge; Falconi-Agapito, Francesca; Privat, Angela; Cruz, Maria; Pagniez, Julie; Papierok, Gérard-Marie; Rhouma, Faten Bel Haj; Torres, Pilar; Lemesre, Jean-Loup; Chenik, Mehdi; Meddeb-Garnaoui, Amel

    2014-01-01

    PSA (Promastigote Surface Antigen) belongs to a family of membrane-bound and secreted proteins present in several Leishmania (L.) species. PSA is recognized by human Th1 cells and provides a high degree of protection in vaccinated mice. We evaluated humoral and cellular immune responses induced by a L. amazonensis PSA protein (LaPSA-38S) produced in a L. tarentolae expression system. This was done in individuals cured of cutaneous leishmaniasis due to L. major (CCLm) or L. braziliensis (CCLb) or visceral leishmaniasis due to L. donovani (CVLd) and in healthy individuals. Healthy individuals were subdivided into immune (HHR-Lm and HHR-Li: Healthy High Responders living in an endemic area for L. major or L. infantum infection) or non immune/naive individuals (HLR: Healthy Low Responders), depending on whether they produce high or low levels of IFN-γ in response to Leishmania soluble antigen. Low levels of total IgG antibodies to LaPSA-38S were detected in sera from the studied groups. Interestingly, LaPSA-38S induced specific and significant levels of IFN-γ, granzyme B and IL-10 in CCLm, HHR-Lm and HHR-Li groups, with HHR-Li group producing TNF-α in more. No significant cytokine response was observed in individuals immune to L. braziliensis or L. donovani infection. Phenotypic analysis showed a significant increase in CD4+ T cells producing IFN-γ after LaPSA-38S stimulation, in CCLm. A high positive correlation was observed between the percentage of IFN-γ-producing CD4+ T cells and the released IFN-γ. We showed that the LaPSA-38S protein was able to induce a mixed Th1 and Th2/Treg cytokine response in individuals with immunity to L. major or L. infantum infection indicating that it may be exploited as a vaccine candidate. We also showed, to our knowledge for the first time, the capacity of Leishmania PSA protein to induce granzyme B production in humans with immunity to L. major and L. infantum infection. PMID:24786587

  13. In vitro evaluation of a soluble Leishmania promastigote surface antigen as a potential vaccine candidate against human leishmaniasis.

    Science.gov (United States)

    Chamakh-Ayari, Rym; Bras-Gonçalves, Rachel; Bahi-Jaber, Narges; Petitdidier, Elodie; Markikou-Ouni, Wafa; Aoun, Karim; Moreno, Javier; Carrillo, Eugenia; Salotra, Poonam; Kaushal, Himanshu; Negi, Narender Singh; Arevalo, Jorge; Falconi-Agapito, Francesca; Privat, Angela; Cruz, Maria; Pagniez, Julie; Papierok, Gérard-Marie; Rhouma, Faten Bel Haj; Torres, Pilar; Lemesre, Jean-Loup; Chenik, Mehdi; Meddeb-Garnaoui, Amel

    2014-01-01

    PSA (Promastigote Surface Antigen) belongs to a family of membrane-bound and secreted proteins present in several Leishmania (L.) species. PSA is recognized by human Th1 cells and provides a high degree of protection in vaccinated mice. We evaluated humoral and cellular immune responses induced by a L. amazonensis PSA protein (LaPSA-38S) produced in a L. tarentolae expression system. This was done in individuals cured of cutaneous leishmaniasis due to L. major (CCLm) or L. braziliensis (CCLb) or visceral leishmaniasis due to L. donovani (CVLd) and in healthy individuals. Healthy individuals were subdivided into immune (HHR-Lm and HHR-Li: Healthy High Responders living in an endemic area for L. major or L. infantum infection) or non immune/naive individuals (HLR: Healthy Low Responders), depending on whether they produce high or low levels of IFN-γ in response to Leishmania soluble antigen. Low levels of total IgG antibodies to LaPSA-38S were detected in sera from the studied groups. Interestingly, LaPSA-38S induced specific and significant levels of IFN-γ, granzyme B and IL-10 in CCLm, HHR-Lm and HHR-Li groups, with HHR-Li group producing TNF-α in more. No significant cytokine response was observed in individuals immune to L. braziliensis or L. donovani infection. Phenotypic analysis showed a significant increase in CD4+ T cells producing IFN-γ after LaPSA-38S stimulation, in CCLm. A high positive correlation was observed between the percentage of IFN-γ-producing CD4+ T cells and the released IFN-γ. We showed that the LaPSA-38S protein was able to induce a mixed Th1 and Th2/Treg cytokine response in individuals with immunity to L. major or L. infantum infection indicating that it may be exploited as a vaccine candidate. We also showed, to our knowledge for the first time, the capacity of Leishmania PSA protein to induce granzyme B production in humans with immunity to L. major and L. infantum infection.

  14. In vitro evaluation of a soluble Leishmania promastigote surface antigen as a potential vaccine candidate against human leishmaniasis.

    Directory of Open Access Journals (Sweden)

    Rym Chamakh-Ayari

    Full Text Available PSA (Promastigote Surface Antigen belongs to a family of membrane-bound and secreted proteins present in several Leishmania (L. species. PSA is recognized by human Th1 cells and provides a high degree of protection in vaccinated mice. We evaluated humoral and cellular immune responses induced by a L. amazonensis PSA protein (LaPSA-38S produced in a L. tarentolae expression system. This was done in individuals cured of cutaneous leishmaniasis due to L. major (CCLm or L. braziliensis (CCLb or visceral leishmaniasis due to L. donovani (CVLd and in healthy individuals. Healthy individuals were subdivided into immune (HHR-Lm and HHR-Li: Healthy High Responders living in an endemic area for L. major or L. infantum infection or non immune/naive individuals (HLR: Healthy Low Responders, depending on whether they produce high or low levels of IFN-γ in response to Leishmania soluble antigen. Low levels of total IgG antibodies to LaPSA-38S were detected in sera from the studied groups. Interestingly, LaPSA-38S induced specific and significant levels of IFN-γ, granzyme B and IL-10 in CCLm, HHR-Lm and HHR-Li groups, with HHR-Li group producing TNF-α in more. No significant cytokine response was observed in individuals immune to L. braziliensis or L. donovani infection. Phenotypic analysis showed a significant increase in CD4+ T cells producing IFN-γ after LaPSA-38S stimulation, in CCLm. A high positive correlation was observed between the percentage of IFN-γ-producing CD4+ T cells and the released IFN-γ. We showed that the LaPSA-38S protein was able to induce a mixed Th1 and Th2/Treg cytokine response in individuals with immunity to L. major or L. infantum infection indicating that it may be exploited as a vaccine candidate. We also showed, to our knowledge for the first time, the capacity of Leishmania PSA protein to induce granzyme B production in humans with immunity to L. major and L. infantum infection.

  15. Limited polymorphism in Plasmodium falciparum ookinete surface antigen, von Willebrand factor A domain-related protein from clinical isolates

    Directory of Open Access Journals (Sweden)

    Eisen Damon P

    2006-07-01

    Full Text Available Abstract Background As malaria becomes increasingly drug resistant and more costly to treat, there is increasing urgency to develop effective vaccines. In comparison to other stages of the malaria lifecycle, sexual stage antigens are under less immune selection pressure and hence are likely to have limited antigenic diversity. Methods Clinical isolates from a wide range of geographical regions were collected. Direct sequencing of PCR products was then used to determine the extent of polymorphisms for the novel Plasmodium falciparum sexual stage antigen von Willebrand Factor A domain-related Protein (PfWARP. These isolates were also used to confirm the extent of diversity of sexual stage antigen Pfs28. Results PfWARP was shown to have non-synonymous substitutions at 3 positions and Pfs28 was confirmed to have a single non-synonymous substitution as previously described. Conclusion This study demonstrates the limited antigenic diversity of two prospective P. falciparum sexual stage antigens, PfWARP and Pfs28. This provides further encouragement for the proceeding with vaccine trials based on these antigens.

  16. Limited polymorphism in Plasmodium falciparum ookinete surface antigen, von Willebrand factor A domain-related protein from clinical isolates.

    Science.gov (United States)

    Richards, Jack S; MacDonald, Nicholas J; Eisen, Damon P

    2006-07-05

    As malaria becomes increasingly drug resistant and more costly to treat, there is increasing urgency to develop effective vaccines. In comparison to other stages of the malaria lifecycle, sexual stage antigens are under less immune selection pressure and hence are likely to have limited antigenic diversity. Clinical isolates from a wide range of geographical regions were collected. Direct sequencing of PCR products was then used to determine the extent of polymorphisms for the novel Plasmodium falciparum sexual stage antigen von Willebrand Factor A domain-related Protein (PfWARP). These isolates were also used to confirm the extent of diversity of sexual stage antigen Pfs28. PfWARP was shown to have non-synonymous substitutions at 3 positions and Pfs28 was confirmed to have a single non-synonymous substitution as previously described. This study demonstrates the limited antigenic diversity of two prospective P. falciparum sexual stage antigens, PfWARP and Pfs28. This provides further encouragement for the proceeding with vaccine trials based on these antigens.

  17. Heteroassembled gold nanoparticles with sandwich-immunoassay LSPR chip format for rapid and sensitive detection of hepatitis B virus surface antigen (HBsAg).

    Science.gov (United States)

    Kim, Jinwoon; Oh, Seo Yeong; Shukla, Shruti; Hong, Seok Bok; Heo, Nam Su; Bajpai, Vivek K; Chun, Hyang Sook; Jo, Cheon-Ho; Choi, Bong Gill; Huh, Yun Suk; Han, Young-Kyu

    2018-06-01

    This study aimed to develop a more sensitive method for the detection of hepatitis B surface antigen (HBsAg) using heteroassembled gold nanoparticles (AuNPs). A single layered localized surface plasmon resonance (LSPR) chip format was developed with antigen-antibody reaction-based detection symmetry using AuNPs, which detected HBsAg at 10 pg/mL. To further improve the detection limit, a modified detection format was fabricated by fixing a secondary antibody (to form a heteroassembled sandwich format) to the AuNP monolayer, which enhanced the detection sensitivity by about 100 times. The developed heteroassembled AuNPs sandwich-immunoassay LSPR chip format was able to detect as little as 100 fg/mL of HBsAg within 10-15 min. In addition, the heteroassembled AuNPs sandwich-immunoassay LSPR chip format did not show any non-specific binding to other tested antigens, including alpha fetoprotein (AFP), C-reactive protein (CRP), and prostate-specific antigen (PSA). These findings confirm that the proposed detection strategy of heteroassembled AuNPs sandwich-immunoassay LSPR chip format may provide a new platform for early diagnosis of various human diseases. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Studies on the surface antigenicity and susceptibility to antibody-dependent killing of developing schistosomula using sera from chronically infected mice and mice vaccinated with irradiated cercariae

    International Nuclear Information System (INIS)

    Bickle, Q.D.; Ford, M.J.

    1982-01-01

    Changes in the surface antigenicity and susceptibility to in vitro killing during development of schistosomula of Schistosoma mansoni were studied using serum from chronically infected mice (CIS) and from mice vaccinated with highly irradiated (20 krad) cercariae (VS). Binding of these sera was quantitated by counting the number of P388D 1 cells (a transformed, macrophage-like cell of mouse origin, bearing Fc receptors for IgG) binding to the parasite surface. Compared with schistosomula derived in vitro by mechanical transformation (MS), schistosomula recovered 3 hr after skin penetration in vitro (SS) showed a significant loss in surface binding of CIS. Schistosomula recovered 3 hr after skin penetration in vivo (SRS) showed even less binding, and this trend continued such that parasites recovered from the lungs 5 days after infection (LS) showed only minimal binding, and 10-day-old worms from the portal system showed no significant binding. In contrast, VS, which bound significantly less well to MS than CIS, showed enhanced binding to SS, and in the face of their declining antigenicity with respect to CIS, 3- to 24-hr SRS maintained this raised level of antigenicity. Although there appeared to be a decline in binding of VS thereafter, LS remained antigenic, still binding as many cells as MS did despite the fact that they also expressed host antigens detected usng antisera raised against mouse RBC. In spite of this persistence of VS binding up to the lung stage, resistance to eosinophil-mediated killing in vitro had developed by 48 hr post-infection, and LS were totally resistant to both eosinophil- and C-mediated killing

  19. Stem Cell Physics. Laser Manipulation of Blood Types: Laser-Stripping-Away of Red Blood Cell Surface Antigens

    Science.gov (United States)

    Stefan, V. Alexander

    2014-03-01

    A novel mechanism of importance for the transfusion medicine[2] is proposed. The interaction of ultrashort wavelength multilaser beams with the flowing blood thin films can lead to a conversion of blood types A, B, and AB into O type.[3] The stripping away of antigens is done by the scanning-multiple-lasers of a high repetition rate in the blue-purple frequency domain. The guiding-lasers are in the red-green frequency domain. The laser force, (parametric interaction with the antigen eigen-oscillation),[4] upon the antigen protein molecule must exceed its weight. Supported by Nikola Tesla Labs, La Jolla, CA.

  20. The promastigote surface antigen gene family of the Leishmania parasite: differential evolution by positive selection and recombination.

    Science.gov (United States)

    Devault, Alain; Bañuls, Anne-Laure

    2008-10-24

    PSA (promastigote surface antigen) is one of the major classes of membrane proteins present at the surface of the parasitic protozoan Leishmania. While it harbours leucine rich repeats, which are suggestive of its involvement in parasite-to-host physical interactions, its exact role is largely unknown. Furthermore, the extent of diversity of this gene family, both in copy number and sequence has not been established. From the newly available complete genome sequences of L. major, L. infantum and L. braziliensis, we have established the complete list of PSA genes, based on the conservation of specific domain architecture. The latter includes an array of leucine rich repeats of unique signature flanked by conserved cysteine-rich domains. All PSA genes code either for secreted or membrane-anchored surface proteins. Besides the few previously identified PSA genes, which are shown here to be part of a relatively large subclass of PSA genes located on chromosome 12, this study identifies seven other PSA subtypes. The latter, whose genes lie on chromosomes 5, 9, 21 and 31 in all three species, form single gene (two genes in one instance) subfamilies, which phylogenetically cluster as highly related orthologs. On the other hand, genes found on chromosome 12 generally show high diversification, as reflected in greater sequence divergence between species, and in an extended set of divergent paralogs. Moreover, we show that the latter genes are submitted to strong positive selection. We also provide evidence that evolution of these genes is driven by intra- and intergenic recombination, thereby modulating the number of LRRs in protein and generating chimeric genes. PSA is a Leishmania family of membrane-bound or secreted proteins, whose main signature consists in a specific LRR sequence. All PSA genes found in the genomes of three sequenced Leishmania species unambiguously distribute into eight subfamilies of orthologs. Seven of these are evolving relatively slowly and could

  1. The promastigote surface antigen gene family of the Leishmania parasite: differential evolution by positive selection and recombination

    Directory of Open Access Journals (Sweden)

    Bañuls Anne-Laure

    2008-10-01

    Full Text Available Abstract Background PSA (promastigote surface antigen is one of the major classes of membrane proteins present at the surface of the parasitic protozoan Leishmania. While it harbours leucine rich repeats, which are suggestive of its involvement in parasite-to-host physical interactions, its exact role is largely unknown. Furthermore, the extent of diversity of this gene family, both in copy number and sequence has not been established. Results From the newly available complete genome sequences of L. major, L. infantum and L. braziliensis, we have established the complete list of PSA genes, based on the conservation of specific domain architecture. The latter includes an array of leucine rich repeats of unique signature flanked by conserved cysteine-rich domains. All PSA genes code either for secreted or membrane-anchored surface proteins. Besides the few previously identified PSA genes, which are shown here to be part of a relatively large subclass of PSA genes located on chromosome 12, this study identifies seven other PSA subtypes. The latter, whose genes lie on chromosomes 5, 9, 21 and 31 in all three species, form single gene (two genes in one instance subfamilies, which phylogenetically cluster as highly related orthologs. On the other hand, genes found on chromosome 12 generally show high diversification, as reflected in greater sequence divergence between species, and in an extended set of divergent paralogs. Moreover, we show that the latter genes are submitted to strong positive selection. We also provide evidence that evolution of these genes is driven by intra- and intergenic recombination, thereby modulating the number of LRRs in protein and generating chimeric genes. Conclusion PSA is a Leishmania family of membrane-bound or secreted proteins, whose main signature consists in a specific LRR sequence. All PSA genes found in the genomes of three sequenced Leishmania species unambiguously distribute into eight subfamilies of orthologs

  2. Interferon-alpha-induced changes in surface antigens in a hairy-cell leukemia (JOK-1), and a Burkitt's lymphoma cell line (Daudi) during in vitro culture

    DEFF Research Database (Denmark)

    Nielsen, B; Madsen, P S; Jensen, A W

    1992-01-01

    In further studying the mechanism of action of IFN-alpha in HCL, we cultured the HCL cell line JOK-1 and the IFN-sensitive Burkitt cell line Daudi with and without IFN-alpha and investigated the changes in density of a number of surface antigens by use of mAb and flow cytometry analyses. During...... culture with IFN-alpha, reproducible changes were induced in both cell lines, which were qualitatively similar but differed quantitatively with small and transient changes in JOK-1. Significant decreases in surface antigen expression were observed for CD 19, 23, 37, and for IgM on both cell lines...... of IFN-alpha in HCL was not paralleled by a specific direct effect on JOK-1 in vitro. Our findings therefore do not support the theory that IFN's mechanism of action in vivo is a direct effect on HC, but suggest that indirect effects are involved. Udgivelsesdato: 1992-Mar...

  3. A simple and inexpensive point-of-care test for hepatitis B surface antigen detection: serological and molecular evaluation.

    Science.gov (United States)

    Gish, R G; Gutierrez, J A; Navarro-Cazarez, N; Giang, K; Adler, D; Tran, B; Locarnini, S; Hammond, R; Bowden, S

    2014-12-01

    Early identification of chronic hepatitis B is important for optimal disease management and prevention of transmission. Cost and lack of access to commercial hepatitis B surface antigen (HBsAg) immunoassays can compromise the effectiveness of HBV screening in resource-limited settings and among marginalized populations. High-quality point-of-care (POC) testing may improve HBV diagnosis in these situations. Currently available POC HBsAg assays are often limited in sensitivity. We evaluated the NanoSign(®) HBs POC chromatographic immunoassay for its ability to detect HBsAg of different genotypes and with substitutions in the 'a' determinant. Thirty-seven serum samples from patients with HBV infection, covering HBV genotypes A-G, were assessed for HBsAg titre with the Roche Elecsys HBsAg II quantification assay and with the POC assay. The POC assay reliably detected HBsAg at a concentration of at least 50 IU/mL for all genotypes, and at lower concentrations for some genotypes. Eight samples with substitutions in the HBV 'a' determinant were reliably detected after a 1/100 dilution. The POC strips were used to screen serum samples from 297 individuals at risk for HBV in local clinical settings (health fairs and outreach events) in parallel with commercial laboratory HBsAg testing (Quest Diagnostics EIA). POC testing was 73.7% sensitive and 97.8% specific for detection of HBsAg. Although the POC test demonstrated high sensitivity over a range of genotypes, false negatives were frequent in a clinical setting. Nevertheless, the POC assay offers advantages for testing in both developed and resource-limited countries due to its low cost (0.50$) and immediately available results. © 2014 John Wiley & Sons Ltd.

  4. Construction and expression of hepatitis B surface antigen escape variants within the "a" determinant by site directed mutagenesis.

    Science.gov (United States)

    Golsaz Shirazi, Forough; Amiri, Mohammad Mehdi; Mohammadi, Hamed; Bayat, Ali Ahmad; Roohi, Azam; Khoshnoodi, Jalal; Zarnani, Amir Hassan; Jeddi-Tehrani, Mahmood; Kardar, Gholam Ali; Shokri, Fazel

    2013-09-01

    The antibody response to hepatitis B surface antigen (HBsAg) controls hepatitis B virus infection. The "a" determinant of HBsAg is the most important target for protective antibody response, diagnosis and immunoprophylaxis. Mutations in this area may induce immune escape mutants and affect the performance of HBsAg assays. To construct clinically relevant recombinant mutant forms of HBsAg and assessment of their reactivity with anti-HBs monoclonal antibodies (MAbs). Wild type (wt) and mutant (mt) HBsAg genes were constructed by site directed mutagenesis and SEOing PCR. The amplified genes were inserted into pCMV6-neo plasmid and transfected in CHO cell line. The expression of wt- and mtHBsAg was assessed by commercial ELISA assays and stable cells were established and cloned by limiting dilution. The recombinant mutants were further characterized using a panel of anti-HBs monoclonal antibodies (MAbs) and the pattern of their reactivity was assessed by ELISA. Ten HBsAg mutants having single mutation within the "a" determinant including P120E, T123N, Q129H, M133L, K141E, P142S, D144A, G145R, N146S and C147S together with a wt form were successfully constructed and expressed in CHO cells. Reactivity of anti-HBs MAbs with mtHBsAgs displayed different patterns. The effect of mutations on antibody binding differed depending on the amino acid involved and its location within the ''a'' determinant. Mutation at amino acids 123 and 145 resulted in either complete loss or significant reduction of binding to all anti-HBs MAbs. Our panel of mtHBsAgs is a valuable tool for assessment of the antibody response to HBV escape mutants and may have substantial implications in HBV immunological diagnostics.

  5. Hepatocellular carcinoma. A study of 50 autopsy cases with detection of hepatitis B surface antigen in fixed tissues.

    Science.gov (United States)

    Perez-Barrios, A; Colina-Ruizdelgado, F; Gallego, I; Martinez-Tello, F J

    1983-03-01

    Fifty patients who died of hepatocellular carcinoma (HCC) were autopsied at the Ciudad Sanitaria "1 degree de Octubre" and the Hospital de la Cruz Roja (Madrid) from 1974 to 1980. Formalin fixed paraffin-embedded autopsy tissue of liver and tumor from the 50 HCC and liver tissue from 50 liver cirrhosis (LC) and from 50 autopsy of non cirrhotic control cases were examined for the presence of cytoplasmic hepatitis B surface antigen (HBsAg). The study was carried out using orcein staining, immunoperoxidase technique (IP) and indirect immunofluorescence (IF). In livers with HCC the HBsAg was detected in the cytoplasm of the hepatocytes in 10 cases (20%) with the orcein staining and in 11 (22%) with the IP and IF techniques. In one case (2%) HBsAg was found in the cytoplasm of tumor cells with the three methods--In four cases (8%) of LC and 2 (4%) control cases cytoplasmic positive cells were found. In 41 patients with HCC HBsAg was studied in the serum by radio-immunoassay (RIA) (13 cases) and immunodiffussion (28 cases). 5 patients (12,1%) were positive and 36 (72%) were negative. In the 5 serum positive HBsAg HCC the staining methods for cytoplasmic HBsAg were positive (100%). In 36 serum negative HBsAg HCC the staining method were positive in 2 cases. The results let us to conclude that HBV is a probable important etiologic factor of HCC in our milieu. 54% of the patients with HCC had a previous history of alcohol abuse; however, histologic features compatible with an alcoholic etiology were found in only 5 cases. Nevertheless we consider that the described histopathologic findings do not exclude excess alcohol consumption as a possible etiologic factor for HCC in our series.

  6. Analysis of complete genome sequence and major surface antigens of Neorickettsia helminthoeca, causative agent of salmon poisoning disease.

    Science.gov (United States)

    Lin, Mingqun; Bachman, Katherine; Cheng, Zhihui; Daugherty, Sean C; Nagaraj, Sushma; Sengamalay, Naomi; Ott, Sandra; Godinez, Al; Tallon, Luke J; Sadzewicz, Lisa; Fraser, Claire; Dunning Hotopp, Julie C; Rikihisa, Yasuko

    2017-07-01

    Neorickettsia helminthoeca, a type species of the genus Neorickettsia, is an endosymbiont of digenetic trematodes of veterinary importance. Upon ingestion of salmonid fish parasitized with infected trematodes, canids develop salmon poisoning disease (SPD), an acute febrile illness that is particularly severe and often fatal in dogs without adequate treatment. We determined and analysed the complete genome sequence of N. helminthoeca: a single small circular chromosome of 884 232 bp encoding 774 potential proteins. N. helminthoeca is unable to synthesize lipopolysaccharides and most amino acids, but is capable of synthesizing vitamins, cofactors, nucleotides and bacterioferritin. N. helminthoeca is, however, distinct from majority of the family Anaplasmataceae to which it belongs, as it encodes nearly all enzymes required for peptidoglycan biosynthesis, suggesting its structural hardiness and inflammatory potential. Using sera from dogs that were experimentally infected by feeding with parasitized fish or naturally infected in southern California, Western blot analysis revealed that among five predicted N. helminthoeca outer membrane proteins, P51 and strain-variable surface antigen were uniformly recognized. Our finding will help understanding pathogenesis, prevalence of N. helminthoeca infection among trematodes, canids and potentially other animals in nature to develop effective SPD diagnostic and preventive measures. Recent progresses in large-scale genome sequencing have been uncovering broad distribution of Neorickettsia spp., the comparative genomics will facilitate understanding of biology and the natural history of these elusive environmental bacteria. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  7. Expression of variant surface antigens by Plasmodium falciparum parasites in the peripheral blood of clinically immune pregnant women indicates ongoing placental infection

    DEFF Research Database (Denmark)

    Ofori, Michael F; Staalsoe, Trine; Bam, Victoria

    2003-01-01

    Placenta-sequestered Plasmodium falciparum parasites that cause pregnancy-associated malaria (PAM) in otherwise clinically immune women express distinct variant surface antigens (VSA(PAM)) not expressed by parasites in nonpregnant individuals. We report here that parasites from the peripheral blood...... of clinically immune pregnant women also express VSA(PAM), making them a convenient source of VSA(PAM) expressors for PAM vaccine research....

  8. Surface co-expression of two different PfEMP1 antigens on single Plasmodium falciparum-infected erythrocytes facilitates binding to ICAM1 and PECAM1

    DEFF Research Database (Denmark)

    Joergensen, Louise; Bengtsson, Dominique C; Bengtsson, Anja

    2010-01-01

    gene is expressed per cell at a time. We measured var mRNA transcript levels by real-time Q-PCR, analysed var gene transcripts by single-cell FISH and directly compared these with PfEMP1 antigen surface expression and cytoadhesion in three different antibody-selected P. falciparum 3D7 sub-lines using...... was found to bind both CD31/PECAM1 and CD54/ICAM1 and to adhere twice as efficiently to human endothelial cells, compared to infected cells having only one PfEMP1 variant on the surface. These new results on PfEMP1 antigen expression indicate that a re-evaluation of the molecular mechanisms involved in P...... live confocal microscopy, flow cytometry and in vitro adhesion assays. We found that one selected parasite sub-line simultaneously expressed two different var genes as surface antigens, on single IE. Importantly, and of physiological relevance to adhesion and malaria pathogenesis, this parasite sub-line...

  9. An Extended Surface Loop on Toxoplasma gondii Apical Membrane Antigen 1 (AMA1 Governs Ligand Binding Selectivity.

    Directory of Open Access Journals (Sweden)

    Michelle L Parker

    Full Text Available Apicomplexan parasites are the causative agents of globally prevalent diseases including malaria and toxoplasmosis. These obligate intracellular pathogens have evolved a sophisticated host cell invasion strategy that relies on a parasite-host cell junction anchored by interactions between apical membrane antigens (AMAs on the parasite surface and rhoptry neck 2 (RON2 proteins discharged from the parasite and embedded in the host cell membrane. Key to formation of the AMA1-RON2 complex is displacement of an extended surface loop on AMA1 called the DII loop. While conformational flexibility of the DII loop is required to expose the mature RON2 binding groove, a definitive role of this substructure has not been elucidated. To establish a role of the DII loop in Toxoplasma gondii AMA1, we engineered a form of the protein where the mobile portion of the loop was replaced with a short Gly-Ser linker (TgAMA1ΔDIIloop. Isothermal titration calorimetry measurements with a panel of RON2 peptides revealed an influential role for the DII loop in governing selectivity. Most notably, an Eimeria tenella RON2 (EtRON2 peptide that showed only weak binding to TgAMA1 bound with high affinity to TgAMA1ΔDIIloop. To define the molecular basis for the differential binding, we determined the crystal structure of TgAMA1ΔDIIloop in complex with the EtRON2 peptide. When analyzed in the context of existing AMA1-RON2 structures, spatially distinct anchor points in the AMA1 groove were identified that, when engaged, appear to provide the necessary traction to outcompete the DII loop. Collectively, these data support a model where the AMA1 DII loop serves as a structural gatekeeper to selectively filter out ligands otherwise capable of binding with high affinity in the AMA1 apical groove. These data also highlight the importance of considering the functional implications of the DII loop in the ongoing development of therapeutic intervention strategies targeting the AMA1-RON

  10. The Leishmania promastigote surface antigen-2 (PSA-2) is specifically recognised by Th1 cells in humans with naturally acquired immunity to L. major.

    Science.gov (United States)

    Kemp, M; Handman, E; Kemp, K; Ismail, A; Mustafa, M D; Kordofani, A Y; Bendtzen, K; Kharazmi, A; Theander, T G

    1998-03-01

    The promastigote surface antigen-2 (PSA-2) is a Leishmania parasite antigen, which can induce Th1-mediated protection against murine leishmaniasis when used as a vaccine. To evaluate PSA-2 as a human vaccine candidate the specific T-cell response to PSA-2 was characterised in individuals immune to cutaneous leishmaniasis. Peripheral blood mononuclear cells from Sudanese individuals with a past history of self-healing cutaneous leishmaniasis proliferated vigorously in response to PSA-2 isolated from Leishmania major, whereas the antigen did not activate cells from presumably unexposed Danes. Peripheral blood mononuclear cells from individuals with previous L. major infection had varying proliferative responses to PSA-2 derived from L. donovani promastigotes. Peripheral blood mononuclear cells activated by PSA-2 from L. major produced high amounts of interferon-gamma and tumour necrosis factor-beta, and little interleukin-4, thereby showing a Th1 cytokine pattern. Parallel cultures showed clear Th1 and Th2 response patterns to purified protein derivative of tuberculin or tetanus toxoid, respectively. Flow cytometric analysis revealed that PSA-2 induced blastogenesis in the CD3 positive population and that these cells were the major source of interferon-gamma. The results show that Th1-like cells recognising PSA-2 are expanded during infection by L. major and that they maintain their Th1-like cytokine profile upon reactivation in vitro. Since immunity to cutaneous leishmaniasis is mediated by antigen-specific Th1-like cells, PSA-2 might be considered a vaccine candidate for human leishmaniasis.

  11. New candidate vaccines against blood-stage Plasmodium falciparum malaria: prime-boost immunization regimens incorporating human and simian adenoviral vectors and poxviral vectors expressing an optimized antigen based on merozoite surface protein 1

    NARCIS (Netherlands)

    Goodman, Anna L.; Epp, C.; Moss, D.; Holder, A. A.; Wilson, J. M.; Gao, G. P.; Long, C. A.; Remarque, E. J.; Thomas, A. W.; Ammendola, V.; Colloca, S.; Dicks, M. D. J.; Biswas, S.; Seibel, D.; van Duivenvoorde, L. M.; Gilbert, S. C.; Hill, A. V. S.; Draper, S. J.

    2010-01-01

    Although merozoite surface protein 1 (MSP-1) is a leading candidate vaccine antigen for blood-stage malaria, its efficacy in clinical trials has been limited in part by antigenic polymorphism and potentially by the inability of protein-in-adjuvant vaccines to induce strong cellular immunity. Here we

  12. Changing serum levels of quantitative hepatitis B surface antigen and hepatitis B virus DNA in hepatitis B virus surface antigen carriers: A follow-up study of an elderly cohort

    Directory of Open Access Journals (Sweden)

    Yuan-Hung Kuo

    2015-02-01

    Full Text Available This study was to elucidate longitudinally quantitative changes of hepatitis B virus (HBV surface antigen (HBsAg and HBV DNA in elder HBsAg carriers in a community. Among 1002 residents screened for HBsAg in 2005, 405 responded to this follow-up study in 2010. Fifty-nine (14.6% were HBsAg carriers in 2005; HBsAg quantification and HBV DNA were measured. HBsAg quantification (cutoff 1600 IU/mL and HBV DNA (cutoff 2000 IU/mL were combined to stratify the participants between two screens. A total of 30 men and 29 women with a mean age of 63.9 ± 7.9 years were enrolled. Quantitative levels of HBsAg and HBV DNA were significantly correlated in 2005 (r = 0.509, p < 0.001 and 2010 (r = 0.777, p < 0.001. Concentrations of HBsAg (IU/mL significantly decreased from 2.2 ± 1.0 log in 2005 to 1.7 ± 1.5 log in 2010 (p < 0.001. The level of HBsAg was decreased in 48 (81.4% individuals and HBsAg was undetectable in eight (13.6%. The annual incidence of HBsAg clearance was 2.7%. These 59 HBsAg carriers in 2005 were divided into four groups: low HBsAg low HBV DNA (n = 32, high HBsAg low HBV DNA (n = 5, low HBsAg high HBV DNA (n = 12 and high HBsAg high HBV DNA (n = 10. All 32 individuals in the low HBsAg low HBV DNA group were still in that group in 2010, whereas only two of the high HBsAg high HBV DNA group became inactive. As with a younger cohort in hospital, HBsAg quantification was still well correlated with HBV DNA in elderly HBsAg carriers in the community. Lower levels of both HBsAg and HBV DNA might represent an inactive HBV infection.

  13. Phage display used for gene cloning of human recombinant antibody against the erythrocyte surface antigen, rhesus D

    DEFF Research Database (Denmark)

    Dziegiel, Morten Hanefeld; Nielsen, L K; Andersen, P S

    1995-01-01

    A novel phage display system has been developed for PCR amplification and cloning of the Fab fragments of human immunoglobulin genes. Using this system, we have cloned an antibody from a mouse-human hybridoma cell line directed against the erythrocyte antigen rhesus D. Intact erythrocytes were used...... Fab phages demonstrates that it is possible to by-pass purification of the antigen of interest. Comparison with published germline sequences demonstrated that the immunoglobulin coding regions had the highest homology to the VH 1.9III and V kappa Hum kappa v325 germline genes, respectively....

  14. Disposable immunoassay for hepatitis B surface antigen based on a graphene paste electrode functionalized with gold nanoparticles and a Nafion-cysteine conjugate

    International Nuclear Information System (INIS)

    Huang, K.-J.; Li, J.; Liu, Y.-M.; Yu, S.; Yu, M.; Cao, X.

    2012-01-01

    We report on the modification of a graphene paste electrode with gold nanoparticles (AuNPs) and a Nafion-L-cysteine composite film, and how this electrode can serve as a platform for the construction of a novel electrochemical immunosensor for the detection of hepatitis B surface antigen (HBsAg). To obtain the immunosensor, an antibody against HBsAg was immobilized on the surface of the electrode, and this process was followed by cyclic voltammetry and electrochemical impedance spectroscopy. The peak currents of a hexacyanoferrate redox system decreased on formation of the antibody-antigen complex on the surface of the electrode. Then increased electrochemical response is thought to result from a combination of beneficial effects including the biocompatibility and large surface area of the AuNPs, the high conductivity of the graphene paste electrode, the synergistic effects of composite film, and the increased quantity of HBsAb adsorbed on the electrode surface. The differential pulse voltammetric responses of the hexacyanoferrate redox pair are proportional to the concentration of HBsAg in the range from 0. 5-800 ng mL -1 , and the detection limit is 0.1 ng mL -1 (at an S/N of 3). The immunosensor is sensitive and stable. (author)

  15. Longitudinal evaluation of humoral immune response and merozoite surface antigen diversity in calves naturally infected with Babesia bovis, in São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Carlos António Matos

    Full Text Available Abstract Babesiosis is an economically important infectious disease affecting cattle worldwide. In order to longitudinally evaluate the humoral immune response against Babesia bovis and the merozoite surface antigen diversity of B. bovis among naturally infected calves in Taiaçu, Brazil, serum and DNA samples from 15 calves were obtained quarterly, from their birth to 12 months of age. Anti-B. bovis IgG antibodies were detected by means of the indirect fluorescent antibody test (IFAT and enzyme-linked immunosorbent assay (ELISA. The polymerase chain reaction (PCR was used to investigate the genetic diversity of B. bovis, based on the genes that encode merozoite surface antigens (MSA-1, MSA-2b and MSA-2c. The serological results demonstrated that up to six months of age, all the calves developed active immunity against B. bovis. Among the 75 DNA samples evaluated, 2, 4 and 5 sequences of the genes msa-1, msa-2b and msa-2c were obtained. The present study demonstrated that the msa-1 and msa-2b genes sequences amplified from blood DNA of calves positive to B. bovis from Taiaçu were genetically distinct, and that msa-2c was conserved. All animals were serologically positive to ELISA and IFAT, which used full repertoire of parasite antigens in despite of the genetic diversity of MSAs.

  16. A Longitudinal Hepatitis B Vaccine Cohort Demonstrates Long-lasting Hepatitis B Virus (HBV) Cellular Immunity Despite Loss of Antibody Against HBV Surface Antigen.

    Science.gov (United States)

    Simons, Brenna C; Spradling, Philip R; Bruden, Dana J T; Zanis, Carolyn; Case, Samantha; Choromanski, Tammy L; Apodaca, Minjun; Brogdon, Hazel D; Dwyer, Gaelen; Snowball, Mary; Negus, Susan; Bruce, Michael G; Morishima, Chihiro; Knall, Cindy; McMahon, Brian J

    2016-07-15

    Long-lasting protection resulting from hepatitis B vaccine, despite loss of antibody against hepatitis B virus (HBV) surface antigen (anti-HBs), is undetermined. We recruited persons from a cohort vaccinated with plasma-derived hepatitis B vaccine in 1981 who have been followed periodically since. We performed serological testing for anti-HBs and microRNA-155 and assessed HBV-specific T-cell responses by enzyme-linked immunospot and cytometric bead array. Study subgroups were defined 32 years after vaccination as having an anti-HBs level of either ≥10 mIU/mL (group 1; n = 13) or anti-HBs level, tested positive for tumor necrosis factor α, interleukin 10, or interleukin 6 production by HBV surface antigen-specific T cells. The frequency of natural killer T cells correlated with the level of anti-HBs (P = .008). The proportion of participants who demonstrated T-cell responses to HBV core antigen varied among the cytokines measured, suggesting some natural exposure to HBV in the study group. No participant had evidence of breakthrough HBV infection. Evidence of long-lasting cellular immunity, regardless of anti-HBs level, suggests that protection afforded by primary immunization with plasma-derived hepatitis B vaccine during childhood and adulthood lasts at least 32 years. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  17. A Study of Molecular Mimicry and Immunological Cross-reactivity between Hepatitis B Surface Antigen and Myelin Mimics

    Directory of Open Access Journals (Sweden)

    Diego Vergani

    2005-01-01

    Full Text Available On the basis of the reported association between hepatitis B vaccination (HBvacc and autoimmune demyelinating complications such as multiple sclerosis (MS, we have looked for aminoacid similarities between the small hepatitis B virus surface antigen (SHBsAg, and the MS-autoantigens myelin basic protein (MBP and myelin oligodendrocyte glycoprotein (MOG that could serve as targets of immunological cross-reactivity. Twenty-mer peptides spanning 4 SHBsAg/MOG and 1 SHBsAg/MBP mimicking pairs, were constructed and tested by ELISA as targets of cross-reactive responses. A total of 147 samples from 58 adults were collected before HBvacc (58/58, and post-HBvacc (48/58 before the second and 41/58 before the third boost. Eighty-seven sera from anti-SHBsAg antibody negative patients with various diseases were tested as pathological controls. Reactivity to at least one of the SHBsAg peptides was found in 8 (14% pre-HBvacc subjects; amongst the remaining 50, reactivity to at least one of the SHBsAg peptides appeared in 47 (94% post-HBvacc. Reactivity to at least one of the MOG mimics was present in 4 (8% pre-HBvacc and in 30 (60% post-HBvacc (p < 0.001. Overall 30/50 (60% vaccinees had SHBsAg/MOG double reactivity on at least one occasion compared to none before-vaccination and in 2 (2% of the pathological controls (p < 0.001 for both. SHBsAg/MOG double reactivity was cross-reactive as confirmed by inhibition studies. At 6 months post-vaccination, 3 of the 4 anti-MOG reactive cases before vaccination and 7 of the 24 (29% of the anti-MOG reactive cases at 3 months post-vaccination had lost their reactivity to MOG5-24. There was no reactivity to the SHBsAg/MBP mimics. None of the vaccinees reported symptoms of demyelinating disorders. In view of the observed SHBsAg/MOG cross-reactivity, the vaccine's possible role as an immunomodulator of viral/self cross-reactivity must be further investigated.

  18. Seroprevalence of hepatitis B e antigen (HBe antigen and B core antibodies (IgG anti-HBcore and IgM anti-HBcore among hepatitis B surface antigen positive blood donors at a Tertiary Centre in Nigeria

    Directory of Open Access Journals (Sweden)

    Akinbami Akinsegun A

    2012-03-01

    Full Text Available Abstract Background Hepatitis B virus (HBV is a common cause of liver disease throughout the world. HBV is transmitted through blood and other body fluids, including semen and saliva. Chronic replication of HBV virons is characterized by persistence circulation of HBsAg, HBeAg and HBV DNA; usually with anti-HBc and occasionally with anti-HBs. Aim: To determine the prevalence of HBeAg, IgG anti-HBcore and IgM anti-HBcore amongst HBsAg positive blood donors. These parameters are reflective of transmissibility and active hepatitis B infection. A cross sectional study was carried out at the blood donor clinics of Lagos State University Teaching Hospital Ikeja and Lagos University Teaching Hospital Idiaraba. A total of 267 donors were recruited to determine HBe antigen, IgG and IgM anti-HBcore antibodies amongst hepatitis BsAg positive donors. Five milliliters of blood was collected from those who tested positive to HBsAg screen during donation. The sera were subjected to enzyme linked immunosorbent assay (ELISA. Pearson chi-squared test was used for the analytical assessment. Findings A total number of 267 HBsAg positive blood donors were studied. A seroprevalence of 8.2% (22 of 267 HBeAg was obtained, 4 of 267 (1.5% were indeterminate while 241 (90.3% tested negative. Only 27 out of 267 donors (10.1% tested positive to IgM anti-HBcore, 234(87.6% tested negative, while 6(2.2% were indeterminate. A higher percentage of 60.7% (162 of 267 tested positive to IgG anti-HBcore, while 39.3% (105 of 267 tested negative. Conclusion There is a low seroprevalence rate of HBeAg-positive chronic hepatitis and relatively high IgG anti-HBcore and IgM anti-HBcore rates in South West Nigeria.

  19. ELISA detection of IgG antibody against a recombinant major surface antigen (Nc-p43) fragment of Neospora caninum in bovine sera

    Science.gov (United States)

    Ahn, Hye-Jin; Kim, Sera; Kim, Dae-Yong

    2003-01-01

    An ELISA was established to measure bovine IgG directed against the recombinant antigenic determinant of Nc-p43, a major surface antigen of Neospora caninum. In a previous study, two thirds of the C-terminal of the molecule was expressed as a 6 × His tagged protein (Ncp43P) for ELISA using 2/3 of the N-terminal of SAG1 from Toxoplasma gondii as a control (TgSAG1A). Among 852 cattle sera collected from stock farms scattered nation-wide, 103 sera (12.1%) were found to react with Ncp43P positively, but no positive reaction was observed with TgSAG1A. This study shows that Ncp43P could be available as an efficient antigen for the diagnosis of neosporosis in cattle. Furthermore, it together with TgSAG1A, could be useful for the differential diagnosis of N. caninum and T. gondii infections in other mammals. PMID:12972732

  20. Phage display used for gene cloning of human recombinant antibody against the erythrocyte surface antigen, rhesus D

    DEFF Research Database (Denmark)

    Dziegiel, Morten Hanefeld; Nielsen, L K; Andersen, P S

    1995-01-01

    A novel phage display system has been developed for PCR amplification and cloning of the Fab fragments of human immunoglobulin genes. Using this system, we have cloned an antibody from a mouse-human hybridoma cell line directed against the erythrocyte antigen rhesus D. Intact erythrocytes were used...... for absorption of the Fab phages. Soluble Fab fragments produced from the cloned material showed identical performance to the parental antibody in agglutination assays. Gel filtration confirmed that the Fab fragment consists of a kappa-Fd heterodimer. The successful use of intact cells for selection of specific...... Fab phages demonstrates that it is possible to by-pass purification of the antigen of interest. Comparison with published germline sequences demonstrated that the immunoglobulin coding regions had the highest homology to the VH 1.9III and V kappa Hum kappa v325 germline genes, respectively....

  1. Selection of scFv Antibody Fragments Binding to Human Blood versus Lymphatic Endothelial Surface Antigens by Direct Cell Phage Display.

    Science.gov (United States)

    Keller, Thomas; Kalt, Romana; Raab, Ingrid; Schachner, Helga; Mayrhofer, Corina; Kerjaschki, Dontscho; Hantusch, Brigitte

    2015-01-01

    The identification of marker molecules specific for blood and lymphatic endothelium may provide new diagnostic tools and identify new targets for therapy of immune, microvascular and cancerous diseases. Here, we used a phage display library expressing human randomized single-chain Fv (scFv) antibodies for direct panning against live cultures of blood (BECs) and lymphatic (LECs) endothelial cells in solution. After six panning rounds, out of 944 sequenced antibody clones, we retrieved 166 unique/diverse scFv fragments, as indicated by the V-region sequences. Specificities of these phage clone antibodies for respective compartments were individually tested by direct cell ELISA, indicating that mainly pan-endothelial cell (EC) binders had been selected, but also revealing a subset of BEC-specific scFv antibodies. The specific staining pattern was recapitulated by twelve phage-independently expressed scFv antibodies. Binding capacity to BECs and LECs and differential staining of BEC versus LEC by a subset of eight scFv antibodies was confirmed by immunofluorescence staining. As one antigen, CD146 was identified by immunoprecipitation with phage-independent scFv fragment. This antibody, B6-11, specifically bound to recombinant CD146, and to native CD146 expressed by BECs, melanoma cells and blood vessels. Further, binding capacity of B6-11 to CD146 was fully retained after fusion to a mouse Fc portion, which enabled eukaryotic cell expression. Beyond visualization and diagnosis, this antibody might be used as a functional tool. Overall, our approach provided a method to select antibodies specific for endothelial surface determinants in their native configuration. We successfully selected antibodies that bind to antigens expressed on the human endothelial cell surfaces in situ, showing that BECs and LECs share a majority of surface antigens, which is complemented by cell-type specific, unique markers.

  2. Energy filtering transmission electron microscopy immunocytochemistry and antigen retrieval of surface layer proteins from Tannerella forsythensis using microwave or autoclave heating with citraconic anhydride.

    Science.gov (United States)

    Moriguchi, K; Mitamura, Y; Iwami, J; Hasegawa, Y; Higuchi, N; Murakami, Y; Maeda, H; Yoshimura, F; Nakamura, H; Ohno, N

    2012-11-01

    Tannerella forsythensis (Bacteroides forsythus), an anaerobic Gram-negative species of bacteria that plays a role in the progression of periodontal disease, has a unique bacterial protein profile. It is characterized by two unique protein bands with molecular weights of more than 200 kDa. It also is known to have a typical surface layer (S-layer) consisting of regularly arrayed subunits outside the outer membrane. We examined the relationship between high molecular weight proteins and the S-layer using electron microscopic immunolabeling with chemical fixation and an antigen retrieval procedure consisting of heating in a microwave oven or autoclave with citraconic anhydride. Immunogold particles were localized clearly at the outermost cell surface. We also used energy-filtering transmission electron microscopy (EFTEM) to visualize 3, 3'-diaminobenzidine tetrahydrochloride (DAB) reaction products after microwave antigen retrieval with 1% citraconic anhydride. The three-window method for electron spectroscopic images (ESI) of nitrogen by the EFTEM reflected the presence of moieties demonstrated by the DAB reaction with horseradish peroxidase (HRP)-conjugated secondary antibodies instead of immunogold particles. The mapping patterns of net nitrogen were restricted to the outermost cell surface.

  3. Breaking tolerance in hepatitis B surface antigen (HBsAg) transgenic mice by vaccination with cross-reactive, natural HBsAg variants

    DEFF Research Database (Denmark)

    Schirmbeck, Reinhold; Dikopoulos, Nektarios; Kwissa, Marcin

    2003-01-01

    Processing exogenous hepatitis B surface antigen (HBsAg) of the hepatitis B virus (HBV) generates the K(b)-binding S(208-215) epitope 1; processing endogenous HBsAg generates the K(b)-binding S(190-197) epitope 2. Cross-reactive CD8(+) T cell responses were primed to epitope 1 but not epitope 2...... HBs-tg mice showed reduced antigenemia. Hence, vaccination with natural HBsAg variants from different HBV sero/genotypes can prime cross-reactive, specific CD8(+) T cell immunity that breaks tolerance to HBsAg....

  4. Hepatitis B virus surface antigen and anti-hepatitis C virus rapid tests underestimate hepatitis prevalence among HIV-infected patients

    DEFF Research Database (Denmark)

    Hønge, Bo Langhoff; Jespersen, S; Medina, C

    2014-01-01

    OBJECTIVES: In the case of coinfection with HIV and hepatitis B virus (HBV) and/or hepatitis C virus (HCV), hepatic disease progression is often accelerated, with higher rates of liver cirrhosis and liver-related mortality. We aimed to evaluate the performance of the rapid tests used routinely...... to detect HBV surface antigen (HBsAg) and anti-HCV among HIV-infected patients in Guinea-Bissau. METHODS: Blood samples from HIV-infected patients in Guinea-Bissau were stored after testing for HBsAg and anti-HCV with rapid tests. Samples were subsequently re-tested for HBsAg and anti-HCV in Denmark...

  5. Insecticide-treated bed nets reduce plasma antibody levels and limit the repertoire of antibodies to Plasmodium falciparum variant surface antigens

    DEFF Research Database (Denmark)

    Askjaer, N; Maxwell, C; Chambo, W

    2001-01-01

    The use of insecticide-treated bed nets (ITN) has been documented to reduce malaria morbidity and mortality in areas with endemic malaria, but concerns have been raised that ITN usage could affect the acquisition of malaria immunity. Several lines of evidence have indicated that antibodies against...... variant surface antigens (VSA) are important in the development of naturally acquired immunity to Plasmodium falciparum malaria and may thus be good indicators of immune status. We have compared the levels of VSA antibodies in plasma from children who have used ITN for 4 years to levels in plasma from...

  6. Hepatitis B surface antigen quantity positively correlates with plasma levels of microRNAs differentially expressed in immunological phases of chronic hepatitis B in children

    DEFF Research Database (Denmark)

    Winther, Thilde Nordmann; Heiberg, Ida Louise; Bang-Berthelsen, Claus Heiner

    2013-01-01

    Children with chronic hepatitis B (CHB) are at high risk of progressive liver disease. It is suggested that a newly-identified panel of 16 microRNAs is important in the pathogenesis of CHB in children. Subviral hepatitis B surface antigen (HBsAg) particles are produced in large excess over...... infectious virions. Interestingly, circulating HBsAg particles have been shown to carry microRNAs. A thorough characterisation of the identified microRNAs and HBsAg over time in plasma from children with CHB may provide useful information about the natural course of childhood CHB....

  7. Comparison of hepatitis B virus core-related antigen and hepatitis B surface antigen for predicting HBeAg seroconversion in chronic hepatitis B patients with pegylated interferon therapy.

    Science.gov (United States)

    Wang, Meng-Lan; Liao, Juan; Wei, Bing; Zhang, Dong-Mei; He, Ming; Tao, Ming-Chuan; Chen, En-Qiang; Tang, Hong

    2018-02-20

    Recent studies revealed that both quantitative hepatitis B surface antigen (qHBsAg) and hepatitis B core-related antigen (qHBcrAg) could serve as a good marker for predicting treatment response and indirectly reflecting intrahepatic cccDNA levels. This study aimed to compare the value of qHBsAg and qHBcrAg in predicting HBeAg seroconversion among patients undergoing PEG-IFN therapy. A total of 31 HBeAg-positive patients, who underwent PEG-IFN therapy for 12 months and follow-up for six months were retrospectively included in this study. The serum qHBsAg level was measured using Elecsys® HBsAg II Quant Assay and serum qHBcrAg level was measured using chemiluminescence enzyme immunoassay. During the 12-month treatment, the absolute levels of serum qHBsAg and qHBcrAg were both lower in patients with HBeAg seroconversion as compared to patients without HBeAg seroconversion, but only the difference in qHBcrAg was significant. During the 6-month follow-up period, both qHBsAg and qHBcrAg levels were rebounded significantly among patients without HBeAg seroconversion. Among patients with HBeAg seroconversion, no sustained significant decline of qHBsAg was observed, but serum qHBcrAg levels continued to decline significantly. The ROC curves analysis showed that both absolute qHBcrAg level and the extent of qHBcrAg decline at month 1 had better performance for the prediction of HBeAg seroconversion at month 6 after treatment, as compared to that of qHBsAg. Early on-treatment qHBcrAg may be a good biomarker for predicting off-treatment HBeAg seroconversion in patients receiving PEG-IFN therapy.

  8. A Sheep in Wolf's Clothing: Listeria innocua Strains with Teichoic Acid-Associated Surface Antigens and Genes Characteristic of Listeria monocytogenes Serogroup 4

    Science.gov (United States)

    Lan, Zheng; Fiedler, Franz; Kathariou, Sophia

    2000-01-01

    Listeria monocytogenes serotype 4b has been implicated in numerous food-borne epidemics and in a substantial fraction of sporadic listeriosis. A unique lineage of the nonpathogenic species Listeria innocua was found to express teichoic acid-associated surface antigens that were otherwise expressed only by L. monocytogenes of serotype 4b and the rare serotypes 4d and 4e. These L. innocua strains were also found to harbor sequences homologous to the gene gtcA, which has been shown to be essential for teichoic acid glycosylation in L. monocytogenes serotype 4b. Transposon mutagenesis and genetic studies revealed that the gtcA gene identified in this lineage of L. innocua was functional in serotype 4b-like glycosylation of the teichoic acids of these organisms. The genomic organization of the gtcA region was conserved between this lineage of L. innocua and L. monocytogenes serotype 4b. Our data are in agreement with the hypothesis that, in this lineage of L. innocua, gtcA was acquired by lateral transfer from L. monocytogenes serogroup 4. The high degree of nucleotide sequence conservation in the gtcA sequences suggests that such transfer was relatively recent. Transfer events of this type may alter the surface antigenic properties of L. innocua and may eventually lead to evolution of novel pathogenic lineages through additional acquisition of genes from virulent listeriae. PMID:11029438

  9. Isolation of recombinant Hepatitis B surface antigen with antibody-conjugated superparamagnetic Fe3O4/SiO2core-shell nanoparticles.

    Science.gov (United States)

    Mostafaei, Mehdi; Hosseini, Seyed Nezamedin; Khatami, Maryam; Javidanbardan, Amin; Sepahy, Abbas Akhavan; Asadi, Ebadullah

    2018-05-01

    In the production process of recombinant Hepatitis B surface antigen (rHBsAg) various separation techniques are used to purify this virus-like particle (VLP). In this study, we developed antibody-conjugated super-paramagnetic Fe 3 O 4 /SiO 2 core-shell nanoparticles as a highly selective method for isolation of expressed rHBsAg in yeast Pichia pastoris. For this purpose, first, iron oxide magnetic nanoparticles (MNP s ) were prepared by co-precipitation method in alkali media and coated with silica. Then the surface was activated by amine groups and conjugated with oxidized antibodies. X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) were used to study the physical properties of MNPs. To evaluate the efficacy of these MNPs as a purification technique successfully synthesized MNPs were added to the rHBsAg sample to couple with the antigen and then be isolated based on their magnetic property. In the present research, in the optimum condition, we could isolate 65% of total rHBsAg from the final vaccine sample with purity above 95%. In this procedure, the maximum obtained specific yield (mg HBsAg/mg MNPs) was equal to 37.6. These results underline the potential application of the immune-magnetic separation (IMS) in the future bioseparation systems. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Effects of pregnancy and intensity of Plasmodium falciparum transmission on immunoglobulin G subclass responses to variant surface antigens

    DEFF Research Database (Denmark)

    Megnekou, Rosette; Staalsoe, Trine; Taylor, Diane W

    2005-01-01

    Placenta-sequestering Plasmodium falciparum involved in the pathogenesis of pregnancy-associated malaria (PAM) in otherwise clinically immune women expresses particular variant surface antigens (VSA(PAM)) on the surface of infected erythrocytes that differ from VSA found in parasitized nonpregnant...... individuals (non-PAM type VSA). We studied levels of immunoglobulin G (IgG) and IgG subclasses with specificity for VSA(PAM) and for non-PAM type VSA in pregnant and nonpregnant women from two sites with different endemicities in Cameroon. We found that VSA(PAM)-specific responses depended on the pregnancy...... status, parity, gestational age, and parasite transmission intensity, whereas only the parasite transmission intensity influenced the levels of IgG specific for non-PAM type VSA. For both types of VSA, the responses were dominated by the cytophilic subclass IgG1, followed by IgG3. In pregnant women...

  11. Clinical Characteristics and Correlation Analysis of Subjects with Chronic Hepatitis B Virus (HBV) Infection and Sustained Low Levels of Hepatitis B Surface Antigen (HBsAg)

    Science.gov (United States)

    Cheng, Jun; Dai, Yuzhu; Yan, Li; Zhou, Huajun; Xu, Xujian

    2018-01-01

    Background The aim of this study was to investigate the clinical characteristics of individuals with chronic hepatitis B virus (HBV) infection with persistent low levels of hepatitis B surface antigen (HBsAg) and to undertake a correlation analysis of the clinical characteristics. Material/Methods The study included 1,204 subjects with chronic HBV infection. Serum HBsAg, HBV envelope antigen (HBeAg), and HBV core antigen (HBcAg) levels were measured using the chemiluminescent microparticle immunoassay (CMIA) and the neutralization test. HBV DNA was measured using real-time fluorescence quantitative polymerase chain reaction (RT-FQ-PCR). Results There were 1,023 subjects in the high-level HBsAg group (HBsAg level ≥10 IU/mL) and 181 subjects in the low-level HBsAg group (HBsAg level HBV-M2), and the asymptomatic carrier (ASC) status was 98.34%. The low-level HBsAg group had a lower HBV DNA-positive rate compared with the high-level HBsAg group (40.33% vs. 75.07%), with a normal distribution across all age groups (P>0.05). The low-level HBsAg group included an older age group. A low-level of HBsAg was positively correlated with a low level of replication of HBV DNA (r=0.452). Conclusions The findings of this study showed that individuals with chronic HBV infection and sustained low-levels of HBsAg were an older population and had a lower level of replicating HBV DNA when compared with individuals with high levels of HBsAg, and the majority (93.7%) were also HBsAg and HBeAg and HBcAg-positive. PMID:29593208

  12. The binding parameters of radiolabelled monoclonal F (ab')2 and Fab' fragments relative to immunoglobulin G in reactions with surface-bound antigens

    International Nuclear Information System (INIS)

    Fjeld, J.G.; Nustad, K.; Michaelsen, T.E.

    1992-01-01

    The binding parameters of iodine-125-labelled intact monoclonal immunoglobulin G (IgG), F(ab') 2 and Fab' fragments were compared. The study was carried out with the two monoclonal antibodies (MoAbs) K13 and K16 specific for human Ig light chains κ and λ, respectively. When testing the 125 I-MoAbs against monodisperse polymer particles coated with the specific antigens, the K a for the F(ab') 2 fragments were similar to that for IgG, while the K a for the Fab' fragments were reduced to 10%-20% of that for IgG. The number N of effective target sites revealed with Fab' was higher than with F(ab') and IgG, presumably because less surface area is occupied by the small Fab' molecules. The immunoreactive fraction F ranged according to IgG>F(ab') 2 >Fab'. The explanation of the moderate difference between the K a of the monoclonal Fab' and the divalent IgG and F(ab') 2 was that the divalent molecules were not divalently attached to the particles. When testing the same antibody preparations against humanlymphoma cells producing Ig with light chains κ or λ, the binding results were less reliable than when particles were utilised, presumably due to antigen shedding. Different MoAbs vary in their loss of immunoreactivity due to enzymatic degradation and the radiolabelling procedure. The preparation of the radiolabelled fragments should therefore be optimized for each MoAb, and evaluation is necessary before injection. Artificial targets with a low leakage of antigen, like the monodisperse polymer particles here applied, are recommended for the in vitro evaluation of the immunoreactivity of labelled MoAb preparations. (orig.)

  13. A reusable localized surface plasmon resonance biosensor for quantitative detection of serum squamous cell carcinoma antigen in cervical cancer patients based on silver nanoparticles array

    Directory of Open Access Journals (Sweden)

    Zhao Q

    2014-02-01

    Full Text Available Qianying Zhao,1 Ruiqi Duan,1 Jialing Yuan,1 Yi Quan,1 Huan Yang,2 Mingrong Xi1 1Department of Gynecology and Obstetrics, West China Second University Hospital, Sichuan University, 2State Key Laboratory of Optical Technologies for Micro-fabrication, Institute of Optics and Electronics, Chinese Academy of Science, Chengdu, Sichuan, People's Republic of China Abstract: Squamous cell carcinoma antigen (SCCa, as a tumor biomarker, plays an important role in adjuvant diagnosis, treatment evaluation, and prognosis prediction for cervical cancer patients. Localized surface plasmon resonance (LSPR technique based on noble metal nanoparticles bypasses the disadvantages of traditional testing strategies, in terms of free-labeling, short assay time, good sensitivity, and selectivity. Herein, we develop a novel and reusable LSPR biosensor for the detection of SCCa. First, a triangle-shaped silver nanoparticle array was fabricated using the nanosphere lithography method. Next, we investigated and verified the feasibility of amino coupling method using 11-mercaptoundecanoic acid (MUA to form a functionalized chip surface with monoclonal anti-SCCa antibodies on the silver nanoparticles for distinct detection of SCCa. Different concentrations of SCCa were successfully tested in both buffer and human serum by the ultrasensitive and specific LSPR system, with a linear quantitative detection range of 0.1–1,000 pM under optimal conditions. With appropriate regeneration solution, for example 50 mM glycine-HCl (pH 2.0, the LSPR biosensor featured effective fabrication reproducibility, which reduced both production cost and testing time. Our study represents the first application of the LSPR biosensor in cervical cancer, and demonstrates that the rapid, simple, and reusable nanochip can serve as a potential alternative for clinical serological diagnosis of SCCa in cervical cancer patients. Keywords: localized surface plasmon resonance, nanotechnology, biosensor

  14. Immune selection and within-host competition can structure the repertoire of variant surface antigens in Plasmodium falciparum -a mathematical model

    DEFF Research Database (Denmark)

    van Noort, Sander P; Nunes, Marta C; Weedall, Gareth D

    2010-01-01

    -studied VSA family is erythrocyte membrane protein 1 (PfEMP1). Each parasite genome encodes about 60 PfEMP1 variants, which are important virulence factors and major targets of host antibody responses. Transcriptional switching is the basis of clonal PfEMP1 variation and immune evasion. A relatively conserved......BACKGROUND: The evolutionary mechanisms structuring the expression pattern of variant surface antigen (VSA) families that allow pathogens to evade immune responses and establish chronic and repeated infections pose major challenges to theoretical research. In Plasmodium falciparum, the best...... evidence regarding VSAs, in particular PfEMP1, to formulate a mathematical model of the evolutionary mechanisms shaping VSA organization and expression patterns. The model integrates the transmission dynamics between hosts and the competitive interactions within hosts, based on the hypothesis that the VSAs...

  15. Differential induction of immunoglobulin G to Plasmodium falciparum variant surface antigens during the transmission season in Daraweesh, Sudan

    DEFF Research Database (Denmark)

    Nielsen, Morten A; Grevstad, Berit; A-Elgadir, Thoraya M E

    2005-01-01

    BACKGROUND: The acquisition of immunoglobulin (Ig) G to variant surface antigens (VSAs) seems important for the development of protective immunity against malaria. Unlike VSAs expressed by parasite isolates associated with uncomplicated malaria, VSAs expressed by parasite isolates associated...... with severe malaria (VSA(SM)) are frequently recognized by IgG. METHODS: We analyzed levels of anti-VSA IgG in 57 individuals in Daraweesh, Sudan, before and after the transmission season. IgG responses to 79 Plasmodium falciparum isolates from children with defined malaria syndromes and exposed to high......G. CONCLUSIONS: Anti-VSA IgG levels decrease in the absence of infection, and an episode of clinical malaria induces IgG against a range of VSAs, particularly VSAs(SM)....

  16. The hybrid EIA test: a specific and sensitive assay for the detection of woodchuck antibody to hepatitis surface antigen (anti-WHs).

    Science.gov (United States)

    Millman, I; Glass, R G

    1988-05-01

    'Ausria II' polystyrene beads (Abbott Labs, N. Chicago) are reacted with woodchuck serum positive for WHsAg in a dilution predetermined by titration. This modified bead is used in a blocking assay to detect the presence of antibody to the surface antigen of woodchuck hepatitis virus (anti-WHs). Serum containing woodchuck anti-WHs and commercial horseradish peroxidase (HRP) labeled anti-HBs are sequentially added. A drop in optical density at 492 nm of 50% or more due to the blocking of HRP conjugated anti-HBs by anti-WHs compared with a control (negative woodchuck serum) is a measure of anti-WHs. The ease and simplicity of converting readily available 'Ausria II' beads to specific reagents for detecting anti-WHs should be welcomed by investigators studying WHV. The method described is both sensitive and reproducible.

  17. Enhancing recovery of recombinant hepatitis B surface antigen in lab-scale and large-scale anion-exchange chromatography by optimizing the conductivity of buffers.

    Science.gov (United States)

    Mojarrad Moghanloo, Gol Mohammad; Khatami, Maryam; Javidanbardan, Amin; Hosseini, Seyed Nezamedin

    2018-01-01

    In biopharmaceutical science, ion-exchange chromatography (IEC) is a well-known purification technique to separate the impurities such as host cell proteins from recombinant proteins. However, IEC is one of the limiting steps in the purification process of recombinant hepatitis B surface antigen (rHBsAg), due to its low recovery rate (rate of 82% in both lab-scale and large-scale weak anion-exchange chromatography without any harsh effect on the purity percentage of rHBsAg. The recovery enhancement via increasing the conductivity of Eq. and Wash. buffers can be explained by their roles in reducing the binding strength and aggregation of retained particles in the column. Moreover, further increase in the salt concentration of Elut. Buffer could substantially promote the ion exchange process and the elution of retained rHBsAg. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Maternally transmitted antibodies to pregnancy-associated variant antigens on the surface of erythrocytes infected with Plasmodium falciparum: relation to child susceptibility to malaria

    DEFF Research Database (Denmark)

    Cot, Michel; Le Hesran, Jean Yves; Staalsoe, Trine

    2003-01-01

    of antibodies in variable surface antigens (VSA) specific to chondroitin sulfate A (CSA)-binding parasites to assess the parasitologic status of the child. Flow cytometry was used to measure levels of antibodies to VSA from CSA-selected and -unselected parasite lines in the cord blood of 79 newborns in Ebolowa......, Cameroon. These newborns were subsequently followed up for 2 years to determine the date of first occurrence of blood parasites and mean parasite density during follow-up. Maternally transmitted antibodies to VSA expressed by CSA-binding parasites, but not antibodies to any other specificity, were...... negatively related to time of first appearance of Plasmodium falciparum in a child's blood and were positively related to mean parasite density during the first 2 years of life. If maternal infection is thought to be the main mechanism influencing susceptibility of the newborn to malaria, antibodies to VSA...

  19. Establishment of a common acute lymphoblastic leukemia cell line (LC4-1) and effects of phorbol myristate acetate (PMA) on the surface antigen expression of the cell line.

    Science.gov (United States)

    Yoshimura, T; Mayumi, M; Yorifuji, T; Kim, K M; Heike, T; Miyanomae, T; Shinomiya, K; Mikawa, H

    1987-09-01

    A common acute lymphoblastic leukemia (ALL) cell line, designated LC4-1, was established from peripheral blood mononuclear cells of a patient with acute non-T-cell ALL. LC4-1 cells were characteristically positive for Ia, B4, and common ALL antigens (CALLA), but negative for B2, Tac, T3, T4, T8, T11, and M1 antigens and E-rosette formation. Approximately 30% of LC4-1 cells expressed detectable amounts of B1 antigens. LC4-1 cells expressed neither Epstein-Barr-virus-associated nuclear antigen (EBNA), cytoplasmic immunoglobulins (cIg) nor surface immunoglobulins (sIg). Gene rearrangements had already occurred in LC4-1 in the D-J region of immunoglobulin heavy chain genes, but not in T-cell receptor (beta-chain) genes, suggesting that LC4-1 is a progenitor cell line of B-cell lineage earlier than pre-B-cells. The expression of cell surface antigens of LC4-1 was changed by treatment with 4-phorbol 12-myristate 13-acetate (PMA) (0.1 ng/ml) for 2 days. Before treatment with PMA, about 98% of LC4-1 cells were positive for B4, CALLA, and Ia. However, following treatment they lost CALLA expression without any change in expression of Ia and B4. There was no change in B1-positive population. The change in surface antigens on LC4-1 cells seems to be due to differentiation induced in the cells by PMA. These results support the hypothesis that CALLA is a differentiation antigen and suggest one possible differentiation pathway for pre-B-cells.

  20. Curcumin induced nanoscale CD44 molecular redistribution and antigen-antibody interaction on HepG2 cell surface

    Energy Technology Data Exchange (ETDEWEB)

    Wang Mu [Department of Chemistry, Jinan University, 601 Huangpu Road West, Tianhe District, Guangzhou 510632 (China); Ruan Yuxia [Department of Ophthalmology, The First Affiliated Hospital, Jinan University, 601 Huangpu Road West, Tianhe District, Guangzhou 510632 (China); Xing Xiaobo; Chen Qian; Peng, Yuan [Department of Chemistry, Jinan University, 601 Huangpu Road West, Tianhe District, Guangzhou 510632 (China); Cai Jiye, E-mail: tjycai@jnu.edu.cn [Department of Chemistry, Jinan University, 601 Huangpu Road West, Tianhe District, Guangzhou 510632 (China)

    2011-07-04

    Graphical abstract: Highlights: > In this study, we investigate the changes of CD44 expression and distribution on HepG2 cells after curcumin treatment. > We find curcumin is able to change the morphology and ultrastructure of HepG2 cells. > Curcumin can reduce the expression of CD44 molecules and induce the nanoscale molecular redistribution on cell surface. > The binding force between CD44-modified AFM tip and the HepG2 cell surface decreases after curcumin-treatment. - Abstract: The cell surface glycoprotein CD44 was implicated in the progression, metastasis and apoptosis of certain human tumors. In this study, we used atomic force microscope (AFM) to monitor the effect of curcumin on human hepatocellular carcinoma (HepG2) cell surface nanoscale structure. High-resolution imaging revealed that cell morphology and ultrastructure changed a lot after being treated with curcumin. The membrane average roughness increased (10.88 {+-} 4.62 nm to 129.70 {+-} 43.72 nm) and the expression of CD44 decreased (99.79 {+-} 0.16% to 75.14 {+-} 8.37%). Laser scanning confocal microscope (LSCM) imaging showed that CD44 molecules were located on the cell membrane. The florescence intensity in control group was weaker than that in curcumin treated cells. Most of the binding forces between CD44 antibodies and untreated HepG2 cell membrane were around 120-220 pN. After being incubated with curcumin, the major forces focused on 70-150 pN (10 {mu}M curcumin-treated) and 50-120 pN (20 {mu}M curcumin-treated). These results suggested that, as result of nanoscale molecular redistribution, changes of the cell surface were in response to external treatment of curcumin. The combination of AFM and LSCM could be a powerful method to detect the distribution of cell surface molecules and interactions between molecules and their ligands.

  1. Curcumin induced nanoscale CD44 molecular redistribution and antigen-antibody interaction on HepG2 cell surface

    International Nuclear Information System (INIS)

    Wang Mu; Ruan Yuxia; Xing Xiaobo; Chen Qian; Peng, Yuan; Cai Jiye

    2011-01-01

    Graphical abstract: Highlights: → In this study, we investigate the changes of CD44 expression and distribution on HepG2 cells after curcumin treatment. → We find curcumin is able to change the morphology and ultrastructure of HepG2 cells. → Curcumin can reduce the expression of CD44 molecules and induce the nanoscale molecular redistribution on cell surface. → The binding force between CD44-modified AFM tip and the HepG2 cell surface decreases after curcumin-treatment. - Abstract: The cell surface glycoprotein CD44 was implicated in the progression, metastasis and apoptosis of certain human tumors. In this study, we used atomic force microscope (AFM) to monitor the effect of curcumin on human hepatocellular carcinoma (HepG2) cell surface nanoscale structure. High-resolution imaging revealed that cell morphology and ultrastructure changed a lot after being treated with curcumin. The membrane average roughness increased (10.88 ± 4.62 nm to 129.70 ± 43.72 nm) and the expression of CD44 decreased (99.79 ± 0.16% to 75.14 ± 8.37%). Laser scanning confocal microscope (LSCM) imaging showed that CD44 molecules were located on the cell membrane. The florescence intensity in control group was weaker than that in curcumin treated cells. Most of the binding forces between CD44 antibodies and untreated HepG2 cell membrane were around 120-220 pN. After being incubated with curcumin, the major forces focused on 70-150 pN (10 μM curcumin-treated) and 50-120 pN (20 μM curcumin-treated). These results suggested that, as result of nanoscale molecular redistribution, changes of the cell surface were in response to external treatment of curcumin. The combination of AFM and LSCM could be a powerful method to detect the distribution of cell surface molecules and interactions between molecules and their ligands.

  2. Virus-like particle production with yeast: ultrastructural and immunocytochemical insights into Pichia pastoris producing high levels of the Hepatitis B surface antigen

    Directory of Open Access Journals (Sweden)

    Adnan Ahmad

    2011-06-01

    Full Text Available Abstract Background A protective immune response against Hepatitis B infection can be obtained through the administration of a single viral polypeptide, the Hepatitis B surface antigen (HBsAg. Thus, the Hepatitis B vaccine is generated through the utilization of recombinant DNA technology, preferentially by using yeast-based expression systems. However, the polypeptide needs to assemble into spherical particles, so-called virus-like particles (VLPs, to elicit the required protective immune response. So far, no clear evidence has been presented showing whether HBsAg assembles in vivo inside the yeast cell into VLPs or later in vitro during down-stream processing and purification. Results High level production of HBsAg was carried out with recombinant Pichia pastoris using the methanol inducible AOX1 expression system. The recombinant vaccine was isolated in form of VLPs after several down-stream steps from detergent-treated cell lysates. Search for the intracellular localization of the antigen using electron microscopic studies in combination with immunogold labeling revealed the presence of HBsAg in an extended endoplasmic reticulum where it was found to assemble into defined multi-layered, lamellar structures. The distance between two layers was determined as ~6 nm indicating that these lamellas represent monolayers of well-ordered HBsAg subunits. We did not find any evidence for the presence of VLPs within the endoplasmic reticulum or other parts of the yeast cell. Conclusions It is concluded that high level production and intrinsic slow HBsAg VLP assembly kinetics are leading to retention and accumulation of the antigen in the endoplasmic reticulum where it assembles at least partly into defined lamellar structures. Further transport of HBsAg to the Golgi apparatus is impaired thus leading to secretory pathway disfunction and the formation of an extended endoplasmic reticulum which bulges into irregular cloud-shaped formations. As VLPs were

  3. Immunogenetic markers associated with a naturally acquired humoral immune response against an N-terminal antigen of Plasmodium vivax merozoite surface protein 1 (PvMSP-1).

    Science.gov (United States)

    Cassiano, Gustavo Capatti; Furini, Adriana A C; Capobianco, Marcela P; Storti-Melo, Luciane M; Almeida, Maria E; Barbosa, Danielle R L; Póvoa, Marinete M; Nogueira, Paulo A; Machado, Ricardo L D

    2016-06-03

    Humoral immune responses against proteins of asexual blood-stage malaria parasites have been associated with clinical immunity. However, variations in the antibody-driven responses may be associated with a genetic component of the human host. The objective of the present study was to evaluate the influence of co-stimulatory molecule gene polymorphisms of the immune system on the magnitude of the humoral immune response against a Plasmodium vivax vaccine candidate antigen. Polymorphisms in the CD28, CTLA4, ICOS, CD40, CD86 and BLYS genes of 178 subjects infected with P. vivax in an endemic area of the Brazilian Amazon were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The levels of IgM, total IgG and IgG subclasses specific for ICB2-5, i.e., the N-terminal portion of P. vivax merozoite surface protein 1 (PvMSP-1), were determined by enzyme-linked immuno assay. The associations between the polymorphisms and the antibody response were assessed by means of logistic regression models. After correcting for multiple testing, the IgG1 levels were significantly higher in individuals recessive for the single nucleotide polymorphism rs3116496 in CD28 (p = 0.00004). Furthermore, the interaction between CD28 rs35593994 and BLYS rs9514828 had an influence on the IgM levels (p = 0.0009). The results of the present study support the hypothesis that polymorphisms in the genes of co-stimulatory components of the immune system can contribute to a natural antibody-driven response against P. vivax antigens.

  4. Cesarean section reduces perinatal transmission of hepatitis B virus infection from hepatitis B surface antigen-positive women to their infants.

    Science.gov (United States)

    Pan, Calvin Q; Zou, Huai-Bin; Chen, Yu; Zhang, Xiaohui; Zhang, Hua; Li, Jie; Duan, Zhongping

    2013-10-01

    Despite appropriate passive and active immunization, perinatal transmission of hepatitis B virus (HBV) still occurs in 5%-10% of infants born to women with high levels of viremia who test positive for the hepatitis B e antigen (HBeAg). We evaluated the effects of cesarean section delivery on perinatal transmission of HBV from women who tested positive for the hepatitis B surface antigen (HBsAg). We analyzed data from 1409 infants born to HBsAg-positive mothers through vaginal delivery (VD) (n = 673), elective caesarean section (ECS) (n = 496), or urgent cesarean section (UCS) (n = 240) who completed appropriate immunization against HBV. The prevention was assumed to have failed for infants who were HBsAg positive when they were 7-12 months old; this information was used to assess transmission rates. HBV infection was transmitted to a smaller percentage of infants born by ECS (1.4%) than by VD (3.4%, P infection to their infants, regardless of method of delivery. There were no differences in maternal or infant morbidity and mortality among the groups. There is a significantly lower rate of vertical transmission of HBV infection to infants delivered by ECS, compared with those delivered vaginally or by UCS. Elective cesarean sections for HBeAg-positive mothers with pre-delivery levels of HBV DNA ≥1,000,000 copies/mL could reduce vertical transmission. Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.

  5. New amperometric and potentiometric immunosensors based on gold nanoparticles/tris(2,2'-bipyridyl)cobalt(III) multilayer films for hepatitis B surface antigen determinations.

    Science.gov (United States)

    Tang, Dianping; Yuan, Ruo; Chai, Yaqin; Fu, Yingzi; Dai, Jianyuan; Liu, Yan; Zhong, Xia

    2005-10-15

    Two generic, fast, sensitive and novel electrochemical immunosensors have been developed. Initially, a layer of plasma-polymerized Nafion film (PPF) was deposited on the platinum electrode surface, then positively charged tris(2,2'-bipyridyl)cobalt(III) (Co(bpy)(3)(3+)) and negatively charged gold nanoparticles were assembled on the PPF-modified Pt electrode by layer-by-layer technique. Finally, hepatitis B surface antibody (HBsAb) was electrostatically adsorbed on the gold nanoparticles surface. Electrochemical behavior of the {Au/Co(bpy)(3)(3+)}(n) multilayer film-modified electrodes was studied. Cyclic voltammetry, electrochemical impedance spectroscopy (EIS) were adopted to monitor the regular growth of the multilayer films. The performance and factors influencing the performance of the resulting immunosensors were studied in detail. The multilayer film-modified immunosensor was used for hepatitis B surface antigen (HBsAg) determination via the amperometric and potentiometric immunosensor systems, and both systems provided the same linear ranges from 0.05 to 4.5 microg/mL with different detection limits for the amperometric system 0.005 microg/mL and for the potentiometric system 0.015 microg/mL. The immunosensors were used to analyse HBsAg in human serum samples. Analytical results of clinical samples show that the developed immunoassay is comparable with the enzyme-linked immunosorbent assays (ELISAs) method, implying a promising alternative approach for detecting HBsAg in the clinical diagnosis. In addition, the multilayer films also showed better stability for 1 month at least.

  6. The extracellular membrane-proximal domain of membrane-bound IgE restricts B cell activation by limiting B cell antigen receptor surface expression.

    Science.gov (United States)

    Vanshylla, Kanika; Opazo, Felipe; Gronke, Konrad; Wienands, Jürgen; Engels, Niklas

    2018-03-01

    Immunoglobulin E (IgE) antibodies are key mediators of allergic reactions. Due to their potentially harmful anaphylactic properties, their production is tightly regulated. The membrane-bound isoform of IgE (mIgE), which is an integral component of the B cell antigen receptor, has been shown to be critical for the regulation of IgE responses in mice. In primate species including humans, mIgE can be expressed in two isoforms that are produced by alternative splicing of the primary ε Ig heavy chain transcript, and differ in the absence or presence of an extracellular membrane-proximal domain (EMPD) consisting of 52 amino acids. However, the function of the EMPD remains unclear. Here, we demonstrate that the EMPD restricts surface expression of mIgE-containing BCRs in human and murine B cells. The EMPD does not interfere with BCR assembly but acts as an autonomous endoplasmic reticulum retention domain. Limited surface expression of EMPD-containing mIgE-BCRs caused impaired activation of intracellular signaling cascades and hence represents a regulatory mechanism that may control the production of potentially anaphylactic IgE antibodies in primate species. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Natural Killer Cell Characteristics in Patients With Chronic Hepatitis B Virus (HBV) Infection Are Associated With HBV Surface Antigen Clearance After Combination Treatment With Pegylated Interferon Alfa-2a and Adefovir

    NARCIS (Netherlands)

    Stelma, Femke; de Niet, Annikki; Tempelmans Plat-Sinnige, Marjan J.; Jansen, Louis; Takkenberg, R. Bart; Reesink, Hendrik W.; Kootstra, Neeltje A.; van Leeuwen, Ester M. M.

    2015-01-01

    The role of natural killer (NK) cells in the process of hepatitis B virus (HBV) surface antigen (HBsAg) clearance and whether their phenotype is related to treatment outcome in patients with chronic hepatitis B are currently unknown. Patients with chronic hepatitis B (HBV DNA load, >17 000 IU/mL)

  8. Cationic Lipid-Formulated DNA Vaccine against Hepatitis B Virus : Immunogenicity of MIDGE-Th1 Vectors Encoding Small and Large Surface Antigen in Comparison to a Licensed Protein Vaccine

    NARCIS (Netherlands)

    Endmann, Anne; Klunder, Katharina; Kapp, Kerstin; Riede, Oliver; Oswald, Detlef; Talman, Eduard G.; Schroff, Matthias; Kleuss, Christiane; Ruiters, Marcel H. J.; Juhls, Christiane

    2014-01-01

    Currently marketed vaccines against hepatitis B virus (HBV) based on the small (S) hepatitis B surface antigen (HBsAg) fail to induce a protective immune response in about 10% of vaccinees. DNA vaccination and the inclusion of PreS1 and PreS2 domains of HBsAg have been reported to represent feasible

  9. Plasmodium falciparum variant surface antigen expression varies between isolates causing severe and nonsevere malaria and is modified by acquired immunity

    DEFF Research Database (Denmark)

    Nielsen, Morten A; Staalsoe, Trine; Kurtzhals, Jørgen

    2002-01-01

    of immunity, as disease-causing parasites appear to be those not controlled by preexisting VSA-specific Abs. In this work we report that VSA expressed by parasites from young Ghanaian children with P. falciparum malaria were commonly and strongly recognized by plasma Abs from healthy children in the same area......, and that the VSA expression pattern is modulated by immunity. This opens the possibility of developing morbidity-reducing vaccines targeting a limited subset of common and particularly virulent VSA.......In areas of endemic parasite transmission, protective immunity to Plasmodium falciparum malaria is acquired over several years with numerous disease episodes. Acquisition of Abs to parasite-encoded variant surface Ags (VSA) on the infected erythrocyte membrane is important in the development...

  10. Radioimmunoassays of hidden viral antigens

    International Nuclear Information System (INIS)

    Neurath, A.R.; Strick, N.; Baker, L.; Krugman, S.

    1982-01-01

    Antigens corresponding to infectious agents may be present in biological specimens only in a cryptic form bound to antibodies and, thus, may elude detection. We describe a solid-phase technique for separation of antigens from antibodies. Immune complexes are precipitated from serum by polyethylene glycol, dissociated with NaSCN, and adsorbed onto nitrocellulose or polystyrene supports. Antigens remain topographically separated from antibodies after removal of NaSCN and can be detected with radiolabeled antibodies. Genomes from viruses immobilized on nitrocellulose can be identified by nucleic acid hybridization. Nanogram quantities of sequestered hepatitis B surface and core antigens and picogram amounts of hepatitis B virus DNA were detected. Antibody-bound adenovirus, herpesvirus, and measles virus antigens were discerned by the procedure

  11. A leucine-rich repeat motif of Leishmania parasite surface antigen 2 binds to macrophages through the complement receptor 3.

    Science.gov (United States)

    Kedzierski, Lukasz; Montgomery, Jacqui; Bullen, Denise; Curtis, Joan; Gardiner, Elizabeth; Jimenez-Ruiz, Antonio; Handman, Emanuela

    2004-04-15

    Membrane glycoconjugates on the Leishmania parasites, notably leishmanolysin and lipophosphoglycan, have been implicated in attachment and invasion of host macrophages. However, the function of parasite surface Ag 2 (PSA-2) and membrane proteophosphoglycan (PPG) has not been elucidated. In this study we demonstrate that native and recombinant Leishmania infantum PSA-2, which consists predominantly of 15 leucine-rich repeats (LRR) and a recombinant LRR domain derived from L. major PPG, bind to macrophages. The interaction is restricted to macrophages and appears to be calcium independent. We have investigated the PSA-2-macrophage interaction to identify the host receptor involved in binding and we show that binding of PSA-2 to macrophages can be blocked by Abs to the complement receptor 3 (CR3, Mac-1). Data derived from mouse macrophage studies were further confirmed using cell lines expressing human CR3, and showed that PSA-2 also binds to the human receptor. This is the first demonstration of a functional role for PSA-2. Our data indicate that in addition to leishmanolysin and lipophosphoglycan, parasite attachment and invasion of macrophages involve a third ligand comprising the LRRs shared by PSA-2 and PPG and that these interactions occur via the CR3.

  12. Cell surface expression level variation between two common Human Leukocyte Antigen alleles, HLA-A2 and HLA-B8, is dependent on the structure of the C terminal part of the alpha 2 and the alpha 3 domains

    DEFF Research Database (Denmark)

    Dellgren, Christoffer; Nehlin, Jan O; Barington, Torben

    2015-01-01

    Constitutive cell surface expression of Human Leukocyte Antigen (HLA) class I antigens vary extremely from tissue to tissue and individual antigens may differ widely in expression levels. Down-regulation of class I expression is a known immune evasive mechanism used by cancer cells and viruses....... Moreover, recent observations suggest that even minor differences in expression levels may influence the course of viral infections and the frequency of complications to stem cell transplantation. We have shown that some human multipotent stem cells have high expression of HLA-A while HLA-B is only weakly...... expressed, and demonstrate here that this is also the case for the human embryonic kidney cell line HEK293T. Using quantitative flow cytometry and quantitative polymerase chain reaction we found expression levels of endogenous HLA-A3 (median 71,204 molecules per cell) 9.2-fold higher than the expression of...

  13. A Conserved DNA Repeat Promotes Selection of a Diverse Repertoire of Trypanosoma brucei Surface Antigens from the Genomic Archive.

    Directory of Open Access Journals (Sweden)

    Galadriel Hovel-Miner

    2016-05-01

    Full Text Available African trypanosomes are mammalian pathogens that must regularly change their protein coat to survive in the host bloodstream. Chronic trypanosome infections are potentiated by their ability to access a deep genomic repertoire of Variant Surface Glycoprotein (VSG genes and switch from the expression of one VSG to another. Switching VSG expression is largely based in DNA recombination events that result in chromosome translocations between an acceptor site, which houses the actively transcribed VSG, and a donor gene, drawn from an archive of more than 2,000 silent VSGs. One element implicated in these duplicative gene conversion events is a DNA repeat of approximately 70 bp that is found in long regions within each BES and short iterations proximal to VSGs within the silent archive. Early observations showing that 70-bp repeats can be recombination boundaries during VSG switching led to the prediction that VSG-proximal 70-bp repeats provide recombinatorial homology. Yet, this long held assumption had not been tested and no specific function for the conserved 70-bp repeats had been demonstrated. In the present study, the 70-bp repeats were genetically manipulated under conditions that induce gene conversion. In this manner, we demonstrated that 70-bp repeats promote access to archival VSGs. Synthetic repeat DNA sequences were then employed to identify the length, sequence, and directionality of repeat regions required for this activity. In addition, manipulation of the 70-bp repeats allowed us to observe a link between VSG switching and the cell cycle that had not been appreciated. Together these data provide definitive support for the long-standing hypothesis that 70-bp repeats provide recombinatorial homology during switching. Yet, the fact that silent archival VSGs are selected under these conditions suggests the 70-bp repeats also direct DNA pairing and recombination machinery away from the closest homologs (silent BESs and toward the rest of

  14. A recombinant multi-antigen vaccine formulation containing Babesia bovis merozoite surface antigens MSA-2a1, MSA-2b and MSA-2c elicits invasion-inhibitory antibodies and IFN-γ producing cells

    Directory of Open Access Journals (Sweden)

    Alba Marina Gimenez

    2016-11-01

    Full Text Available Abstract Background Babesia bovis is a tick-transmitted protozoan hemoparasite and the causative agent of bovine babesiosis, a potential risk to more than 500 million cattle worldwide. The vaccines currently available are based on attenuated parasites, which are difficult to produce, and are only recommended for use in bovines under one year of age. When used in older animals, these vaccines may cause life-threatening clinical symptoms and eventually death. The development of a multi-subunit recombinant vaccine against B. bovis would be attractive from an economic standpoint and, most importantly, could be recommended for animals of any age. In the present study, recombinant ectodomains of MSA-2a1, MSA-2b and MSA-2c antigens were expressed in Pichia pastoris yeast as secreted soluble peptides. Results The antigens were purified to homogeneity, and biochemically and immunologically characterized. A vaccine formulation was obtained by emulsifying a mixture of the three peptides with the adjuvant Montanide ISA 720, which elicited high IgG antibody titers against each of the above antigens. IgG antibodies generated against each MSA-antigen recognized merozoites and significantly inhibited the invasion of bovine erythrocytes. Cellular immune responses were also detected, which were characterized by splenic and lymph node CD4+ T cells producing IFN-γ and TNF-α upon stimulation with the antigens MSA-2a1 or MSA-2c. Conclusions These data strongly suggest the high protective potential of the presented formulation, and we propose that it could be tested in vaccination trials of bovines challenged with B. bovis.

  15. Identification of a rare point mutation at C-terminus of merozoite surface antigen-1 gene of Plasmodium falciparum in eastern Indian isolates.

    Science.gov (United States)

    Raj, Dipak Kumar; Das, Bibhu Ranjan; Dash, A P; Supakar, Prakash C

    2004-01-01

    Merozoite surface antigen-1 (MSA-1) of Plasmodium falciparum is highly immunogenic in human. Several studies suggest that MSA-1 protein is an effective target for a protective immune response. Attempt has been made to find new point mutations by analyzing 244 bp [codon 1655(R) to 1735 (I)] relatively conserved C-terminus region of MSA-1 gene in 125 isolates. This region contains two EGF like domains, which are involved in generating protective immune response in human. Point mutations in this region are very much important in view of vaccine development. Searching of mutational hot spots in MSA-1 protein by sequencing method in a representative number of isolates is quite critical and expensive. Therefore, in this study slot blot and PCR-SSCP method have been used to find out new mutations in the individual isolates showing alterations in the mobility of DNA fragment. Sequencing of the altered bands from the SSCP gel shows a rare non-synonymous point mutation in 7 (5.6%) of the 125 isolates at amino acid position 1704 of MSA-1 gene where isoleucine is replaced by valine.

  16. Response-guided therapy of regimens based on PEG-interferon for chronic hepatitis B using on-treatment hepatitis B surface antigen quantification: a meta-analysis.

    Science.gov (United States)

    Peng, Hong; Wei, Fang; Liu, Jun-Ying; Hu, Huai-Dong; Ren, Hong; Hu, Peng

    2015-10-01

    The efficacy of on-treatment hepatitis B surface antigen (HBsAg) levels in guiding pegylated interferon (PEG-IFN) therapy for chronic hepatitis B (CHB) infections is still controversial. The aim of this study is to quantitatively evaluate the efficacy of on-treatment HBsAg levels as a response-guided therapy strategy to guide PEG-IFN-based therapies for CHB. We searched PUBMED, EMBASE, and the Cochrane Library (1997-2013) for clinical research involving HBsAg quantification, and the response to PEG-IFN-based therapy. Pooled effect of HBsAg levels on guiding PEG-IFN-based therapies for CHB was evaluated using fixed-effects or random-effects model. From 13 studies (n = 1493 patients), patients with optimal on-treatment HBsAg levels were found to have a greater chance of attaining a response (RR 5.17, 95 % CI 3.75-7.11, p response rate was 54 % (95 % CI 44-63 %). At week 12, patients without optimal on-treatment HBsAg levels had hardly achieved a response (the early non-response rate: 99 %, 95 % CI 98-100 %). At 24 weeks, the response rate increased to 79 % in HBeAg-negative patients. This meta-analysis suggested that on-treatment HBsAg quantification is effective in guiding the therapy of PEG-IFN in CHB infections, especially in HBeAg-negative patients.

  17. IgA and IgG antibodies against surface antigens of Pseudomonas aeruginosa in sputum and serum from patients with cystic fibrosis.

    Science.gov (United States)

    Schiøtz, P O; Høiby, N; Permin, H; Wiik, A

    1979-06-01

    Eleven cystic fibrosis (CF) patients chronically infected in the lungs with mucoid Pseudomonas aeruginosa and presenting multiple precipitins in serum against this bacterium (CF + P) and 10 CF patients without P. aeruginosa infection (CF-P) had their serum and sputum sol phase specimens examined for antibodies of the IgA and IgG classes against surface antigens of P. aeruginosa by means of an indirect immunofluorescence technique. Both the IgA and IgG antibody titres demonstrated in serum and sputum of the CF + P patients were significantly higher than in those of the CF-P patients (p less than 0.01). The titre of IgA antibodies in the sputum was higher than in serum in 3 cases indicating local pulmonary production of specific IgA antibodies. The role of the demonstrated antibodies in the local pulmonary immune defense mechanisms and the possible patogenesis of the pulmonary tissue damage in CF patients is discussed.

  18. Antibody response to a major human Pneumocystis carinii surface antigen in patients without evidence of immunosuppression and in patients with suspected atypical pneumonia

    DEFF Research Database (Denmark)

    Lundgren, Bettina; Lebech, M; Lind, K

    1993-01-01

    G antibodies to gp95 was significantly lower in the age group 1 to 9 years (30%, 23/77) compared to persons 10 to 19 years old (56%, 49/88). In the age group 1 to 14 years there was a significant correlation between the percentage of persons with IgG antibodies to gp95 and age. In 106 consecutive patients...... of these patients had a verified Pneumocystis carinii pneumonia, and the two others were elderly men in whom no microbiological diagnosis of the pneumonia was established. Thus, it is concluded that IgG antibodies to gp95 develop in the majority of nonimmunosuppressed persons before the age of 13. Furthermore......IgG and IgM antibodies to a purified human Pneumocystis carinii surface antigen (gp95) were measured in 694 serum specimens from two different population groups using an EIA technique. In a population of 441 patients with no evidence of immunosuppression, the percentage of persons positive for Ig...

  19. Hepatitis B vaccination coverage and risk factors associated with incomplete vaccination of children born to hepatitis B surface antigen-positive mothers, Denmark, 2006 to 2010.

    Science.gov (United States)

    Kunoee, Asja; Nielsen, Jens; Cowan, Susan

    2016-01-01

    In Denmark, universal screening of pregnant women for hepatitis B has been in place since November 2005, with the first two years as a trial period with enhanced surveillance. It is unknown what the change to universal screening without enhanced surveillance has meant for vaccination coverage among children born to hepatitis B surface antigen (HBsAg)-positive mothers and what risk factors exist for incomplete vaccination. This retrospective cohort study included 699 children of mothers positive for HBsAg. Information on vaccination and risk factors was collected from central registers. In total, 93% (651/699) of the children were vaccinated within 48 hours of birth, with considerable variation between birthplaces. Only 64% (306/475) of the children had received all four vaccinations through their general practitioner (GP) at the age of two years, and 10% (47/475) of the children had received no hepatitis B vaccinations at all. Enhanced surveillance was correlated positively with coverage of birth vaccination but not with coverage at the GP. No or few prenatal examinations were a risk factor for incomplete vaccination at the GP. Maternity wards and GPs are encouraged to revise their vaccination procedures and routines for pregnant women, mothers with chronic HBV infection and their children.

  20. Radioimmunoassay of surface antigen and core antibody of hepatitis B virus. Comparison of kits AUSRIA/CORE; AUSRIA II-125 and CORAB

    Energy Technology Data Exchange (ETDEWEB)

    Kselikova, M.; Urbankova, J. (Ustav Hematologie a Krevni Transfuze, Prague (Czechoslovakia))

    1984-08-01

    The sensitivity is compared of determination of surface antigen HBsAg and nuclear antibody HBcAb of the hepatitis B virus using kits for separate (AUSRIA II-125, CORAB) and simultaneous (AUSRIAsup(R)/CORE) determinations of third generation tests in selected samples of medical personnel, HBsAg carriers, patients at a dialysis centre, blood donors and in sera of HBsAg carriers diluted in steps from 4x10/sup -2/ to 4x10/sup -7/. HBsAg is always determined using the RIA technique, HBcAb is determined using the technique of radioimmunoassay with the CORAB kit and with the AUSRIA sup(R)/CORE kit using enzymeimmunoassay. The sensitivity of determination using the AUSRIA sup(R)/CORE kit is at least as good for both investigated indicators of the hepatitis B virus and that obtained using separate determination of HBsAg (AUSRIA II-125) and HBcAb (CORAB), this also using modified photocolorimetric determination. Only one AUSRIA/sup R//CORE kit was available for the investigation and the informative character of the report is emphasized.

  1. Hepatitis B surface antigen titer is a good indicator of durable viral response after entecavir off-treatment for chronic hepatitis B.

    Science.gov (United States)

    Lee, Han Ah; Seo, Yeon Seok; Park, Seung Woon; Park, Sang Jung; Kim, Tae Hyung; Suh, Sang Jun; Jung, Young Kul; Kim, Ji Hoon; An, Hyunggin; Yim, Hyung Joon; Yeon, Jong Eun; Byun, Kwan Soo; Um, Soon Ho

    2016-09-01

    Clear indicators for stopping antiviral therapy in chronic hepatitis B (CHB) patients are not yet available. Since the level of hepatitis B surface antigen (HBsAg) is correlated with covalently closed circular DNA, the HBsAg titer might be a good indicator of the off-treatment response. This study aimed to determine the relationship between the HBsAg titer and the entecavir (ETV) off-treatment response. This study analyzed 44 consecutive CHB patients (age, 44.6±11.4 years, mean±SD; men, 63.6%; positive hepatitis B envelope antigen (HBeAg) at baseline, 56.8%; HBV DNA level, 6.8±1.3 log 10 IU/mL) treated with ETV for a sufficient duration and in whom treatment was discontinued after HBsAg levels were measured. A virological relapse was defined as an increase in serum HBV DNA level of >2000 IU/mL, and a clinical relapse was defined as a virological relapse with a biochemical flare, defined as an increase in the serum alanine aminotransferase level of >2 × upper limit of normal. After stopping ETV, virological relapse and clinical relapse were observed in 32 and 24 patients, respectively, during 20.8±19.9 months of follow-up. The cumulative incidence rates of virological relapse were 36.2% and 66.2%, respectively, at 6 and 12 months, and those of clinical relapse were 14.3% and 42.3%. The off-treatment HBsAg level was an independent factor associated with clinical relapse (hazard ratio, 2.251; 95% confidence interval, 1.076-4.706; P =0.031). When patients were grouped according to off-treatment HBsAg levels, clinical relapse did not occur in patients with an off-treatment HBsAg level of ≤2 log 10 IU/mL (n=5), while the incidence rates of clinical relapse at 12 months after off-treatment were 28.4% and 55.7% in patients with off-treatment HBsAg levels of >2 and ≤3 log 10 IU/mL (n=11) and >3 log 10 IU/mL (n=28), respectively. The off-treatment HBsAg level is closely related to clinical relapse after treatment cessation. A serum HBsAg level of response in CHB

  2. Hepatitis B surface antigen titer is a good indicator of durable viral response after entecavir off-treatment for chronic hepatitis B

    Directory of Open Access Journals (Sweden)

    Han Ah Lee

    2016-09-01

    Full Text Available Background/Aims Clear indicators for stopping antiviral therapy in chronic hepatitis B (CHB patients are not yet available. Since the level of hepatitis B surface antigen (HBsAg is correlated with covalently closed circular DNA, the HBsAg titer might be a good indicator of the off-treatment response. This study aimed to determine the relationship between the HBsAg titer and the entecavir (ETV off-treatment response. Methods This study analyzed 44 consecutive CHB patients (age, 44.6±11.4 years, mean±SD; men, 63.6%; positive hepatitis B envelope antigen (HBeAg at baseline, 56.8%; HBV DNA level, 6.8±1.3 log10 IU/mL treated with ETV for a sufficient duration and in whom treatment was discontinued after HBsAg levels were measured. A virological relapse was defined as an increase in serum HBV DNA level of >2000 IU/mL, and a clinical relapse was defined as a virological relapse with a biochemical flare, defined as an increase in the serum alanine aminotransferase level of >2 × upper limit of normal. Results After stopping ETV, virological relapse and clinical relapse were observed in 32 and 24 patients, respectively, during 20.8±19.9 months of follow-up. The cumulative incidence rates of virological relapse were 36.2% and 66.2%, respectively, at 6 and 12 months, and those of clinical relapse were 14.3% and 42.3%. The off-treatment HBsAg level was an independent factor associated with clinical relapse (hazard ratio, 2.251; 95% confidence interval, 1.076–4.706; P=0.031. When patients were grouped according to off-treatment HBsAg levels, clinical relapse did not occur in patients with an off-treatment HBsAg level of ≤2 log10 IU/mL (n=5, while the incidence rates of clinical relapse at 12 months after off-treatment were 28.4% and 55.7% in patients with off-treatment HBsAg levels of >2 and ≤3 log10 IU/mL (n=11 and >3 log10 IU/mL (n=28, respectively. Conclusion The off-treatment HBsAg level is closely related to clinical relapse after treatment

  3. Evaluation of protective immune responses induced by DNA vaccines encoding Toxoplasma gondii surface antigen 1 (SAG1) and 14-3-3 protein in BALB/c mice.

    Science.gov (United States)

    Meng, Min; He, Shenyi; Zhao, Guanghui; Bai, Yang; Zhou, Huaiyu; Cong, Hua; Lu, Gang; Zhao, Qunli; Zhu, Xing-Quan

    2012-11-26

    Toxoplasmosis, caused by an obligate intracellular protozoan parasite Toxoplasma gondii, has been a serious clinical and veterinary problem. Effective DNA vaccines against T. gondii can prevent and control the spread of toxoplasmosis, which is important for both human health and the farming industry. The T. gondii 14-3-3 protein has been proved to be antigenic and immunogenic and was a potential vaccine candidate against toxoplasmosis. In this study, we evaluated the immune responses induced by recombinant plasmids encoding T. gondii surface antigen 1 (SAG1) and 14-3-3 protein by immunizing BALB/c mice intramuscularly. In the present study, BALB/c mice were randomly divided into five groups, including three experimental groups (pSAG1, p14-3-3 and pSAG1/14-3-3) and two control groups (PBS and pBudCE4.1), and were immunized intramuscularly three times. The levels of IgG antibodies and cytokine production in mouse sera were determined by enzyme-linked immunosorbent assays (ELISA). Two weeks after the last immunization, all mice were challenged intraperitoneally (i.p.) with 1×10(4) tachyzoites of T. gondii and the survival time of mice was observed and recorded every day. Mice vaccinated with pSAG1, p14-3-3 or pSAG1/14-3-3 developed high levels of IgG2a and gamma interferon (IFN-γ) and low levels of interleukin-4 (IL-4) and interleukin-10 (IL-10) compared to control groups (PBS or pBudCE4.1), which suggested a modulated Th1 type immune response (Pmice in experimental groups was longer than control groups (Pmice and was a novel DNA vaccine candidate against toxoplasmosis, and the immune protective efficacy elicited by SAG1 gene was also demonstrated. Our results also showed multi-gene vaccine significantly enhanced immune responses and protective efficacy and was superior to the single-gene vaccine.

  4. Intracellular trafficking of bio-nanocapsule-liposome complex: Identification of fusogenic activity in the pre-S1 region of hepatitis B virus surface antigen L protein.

    Science.gov (United States)

    Somiya, Masaharu; Sasaki, Yasuo; Matsuzaki, Takashi; Liu, Qiushi; Iijima, Masumi; Yoshimoto, Nobuo; Niimi, Tomoaki; Maturana, Andrés Daniel; Kuroda, Shun'ichi

    2015-08-28

    Bio-nanocapsules (BNCs) are a hollow nanoparticle consisting of about 100-nm liposome (LP) embedding about 110 molecules of hepatitis B virus (HBV) surface antigen (HBsAg) L protein as a transmembrane protein. Owing to the human hepatocyte-recognizing domains on the N-terminal region (pre-S1 region), BNCs have recently been shown to attach and enter into human hepatic cells using the early infection mechanism of HBV. Since BNCs could form a complex with an LP containing various drugs and genes, BNC-LP complexes have been used as a human hepatic cell-specific drug and gene-delivery system in vitro and in vivo. However, the role of BNCs in cell entry and intracellular trafficking of payloads in BNC-LP complexes has not been fully elucidated. In this study, we demonstrate that low pH-dependent fusogenic activity resides in the N-terminal part of pre-S1 region (NPLGFFPDHQLDPAFG), of which the first FF residues are essential for the activity, and which facilitates membrane fusion between LPs in vitro. Moreover, BNC-LP complexes can bind human hepatic cells specifically, enter into the cells via clathrin-mediated endocytosis, and release their payloads mostly into the cytoplasm. Taken together, the BNC portion of BNC-LP complexes can induce membrane fusion between LPs and endosomal membranes under low pH conditions, and thereby facilitate the endosomal escape of payloads. Furthermore, the fusogenic domain of the pre-S1 region of HBsAg L protein may play a pivotal role in the intracellular trafficking of not only BNC-LP complexes but also of HBV. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. [Comparative Study for Anti-Hepatitis B Surface Antigen Titers Based on Two Measurement Methods: Using Monoclonal Antibodies Isolated from Hepatitis B Vaccinated Recipients].

    Science.gov (United States)

    Oone, Kumiko; Kani, Satomi; Oohashi, Minoru; Shinkai, Noboru; Inoue, Takako; Wakimoto, Yukio; Tanaka, Yasuhito

    2015-08-01

    As anti-hepatitis B surface antigen (anti-HBs) titers vary depending on the measurement methods, we compared two different methods to measure anti-HBs titers in sera and HBs monoclonal antibodies. The sera from 182 HB virus-resolved patients who were negative for HBsAg but positive for antiHB core protein (HBc) and/or anti-HBs were obtained. The measurement of anti-HBs was compared using either Lumipulse G1200 or Architect i2000SR. Six different monoclonal antibody (mAbs) clones isolated from healthy individuals inoculated with hepatitis B vaccine Bimmugen (genotype C) were used. A statistically significant correlation in anti-HBs titers was found between the two methods tested (Y = 0.951X + 100.7, R = 0.813, p Lumipulse and 12 (6.6%) were opposite results. Measuring 2 mAbs with HBV neutralizing activity, the titers of the 116 antibody (1.0 μg/mL) were comparable (689.3 mIU/mL by Lumipulse and 440.7 mIU/mL by Architect), whereas those of the 478 antibody (1.0 μg/mL) were much lower by Architect than by Lumipulse (42.6 vs. 818.6 mIU/mL, respectively). Of four other mAbs without HBV neutralizing activity, equal titers were observed for one; two mAbs had less anti-HB titers by Architect; and one was below the cut-off index (Lumipulse, and the potential ability to detect the 478 antibody with neutralizing activity is low, indicating that Architect might underestimate anti-HBs titers. Future studies should standardize the anti-HBs titer measurement system.

  6. Development and evaluation of an in-house ELISA to detect hepatitis B virus surface antigen in resource-limited settings.

    Science.gov (United States)

    Fatema, K; Tabassum, S; Nessa, A; Jahan, M

    2013-08-01

    Hepatitis B virus (HBV) infection is of global public health concern. Among various serological tests used for the diagnosis and screening of HBV infection, the enzyme-linked immunosorbent assay (ELISA) to detect hepatitis B surface antigen (HbsAg) is most widely used. The present study was designed to develop and standardize a cost effective in-house ELISA for the detection of HbsAg and compare its performance with two established commercial kits. The concentrations of coating antibody, conjugates and sera were fixed by checkerboard titration. Using known HBsAg positive and negative sera, four different concentrations (1, 0.5, 0.25 and 0.125 microg/well) of coating anti-HBs were applied. Similarly, serial dilutions of patients' sera (1 in 2, 1 in 3, 1 in 5 and 1 in 9) and conjugates (1 in 2, 1 in 3, 1 in 5, 1 in 9 and 1 in 17) were evaluated by checkerboard titration. The optimal concentration of coating antibody was determined at 0.25 microg/well and 1 in 9 dilution for both conjugates and sera. The performance comparison of our in-house ELISA showed excellent correlation with two commercial kits (Pearson 0.957, P = 0.001 for monoclonal antibody coated kit and Pearson 0.929, P = 0.000 for polyclonal antibody coated kit) when OD values were compared. All commercial kit proven positive samples was positive while all negative samples were negative with the in-house ELISA resulting in 100% sensitivity and specificity. The results of our study demonstrated that our in-house ELISA for detection of HBsAg was equally as sensitive and specific as two well-known commercial kits. Thus, this system may be a useful tool for diagnostic and screening purposes, as well as outbreak investigations.

  7. Luteolin-7-O-Glucoside Present in Lettuce Extracts Inhibits Hepatitis B Surface Antigen Production and Viral Replication by Human Hepatoma Cells in Vitro

    Directory of Open Access Journals (Sweden)

    Xiao-Xian Cui

    2017-12-01

    Full Text Available Hepatitis B virus (HBV infection is endemic in Asia and chronic hepatitis B (CHB is a major public health issue worldwide. Current treatment strategies for CHB are not satisfactory as they induce a low rate of hepatitis B surface antigen (HBsAg loss. Extracts were prepared from lettuce hydroponically cultivated in solutions containing glycine or nitrate as nitrogen sources. The lettuce extracts exerted potent anti-HBV effects in HepG2 cell lines in vitro, including significant HBsAg inhibition, HBV replication and transcription inhibition, without exerting cytotoxic effects. When used in combination interferon-alpha 2b (IFNα-2b or lamivudine (3TC, the lettuce extracts synergistically inhibited HBsAg expression and HBV replication. By using differential metabolomics analysis, Luteolin-7-O-glucoside was identified and confirmed as a functional component of the lettuce extracts and exhibited similar anti-HBV activity as the lettuce extracts in vitro. The inhibition rate on HBsAg was up to 77.4%. Moreover, both the lettuce extracts and luteolin-7-O-glucoside functioned as organic antioxidants and, significantly attenuated HBV-induced intracellular reactive oxygen species (ROS accumulation. Luteolin-7-O-glucoside also normalized ROS-induced mitochondrial membrane potential damage, which suggests luteolin-7-O-glucoside inhibits HBsAg and HBV replication via a mechanism involving the mitochondria. Our findings suggest luteolin-7-O-glucoside may have potential value for clinical application in CHB and may enhance HBsAg and HBV clearance when used as a combination therapy.

  8. Anisotropic In Situ-Coated AuNPs on Screen-Printed Carbon Surface for Enhanced Prostate-Specific Antigen Impedimetric Aptasensor

    Science.gov (United States)

    Do, Tram T. N.; Van Phi, Toan; Nguy, Tin Phan; Wagner, Patrick; Eersels, Kasper; Vestergaard, Mun'delanji C.; Truong, Lien T. N.

    2017-06-01

    An impedimetric aptasensor has been used to study the effect of charge transfer on the binding of prostate-specific antigen (PSA) to its aptamer. Full understanding of this mechanism will be beneficial to further improve its sensitivity for PSA detection in human semen at physiologically relevant concentrations. Bare gold electrodes (SPAuEs) and gold nanoparticles (AuNPs)-coated screen-printed carbon ink electrodes (AuNPs/SPCEs) were coated with aptamer solution at various concentrations and the sensor response to increasing PSA concentration in buffer solution examined. AuNPs were deposited onto carbon electrodes in 10 cycles. AuNPs/SPCEs were then coated with a self-assembled monolayer (SAM) of 16-mercaptohexadecanoic acid prior to aptamer immobilization at dose of 5 μg mL-1. The results indicate that anisotropic AuNPs/SPCEs outperform bare gold electrodes in terms of decreased amount of aptamer bunches as well as the number of intermediate PSA-aptamer complexes formed on the electrode surface. The key finding is that the fabricated aptasensor is sensitive enough [limit of detection (LoD) 1.95 ng mL-1] for early diagnosis of prostate cancer and displays linear response in the physiologically relevant concentration range (0 ng mL-1 to 10 ng mL-1), as shown by the calibration curve of the relative change in electron transfer resistance (Δ R CT) versus PSA concentration when aptamer/SAM/AuNPs/SPCEs were exposed to buffer containing PSA at different concentrations.

  9. Impact of "a" determinant mutations on detection of hepatitis B surface antigen (HBsAg) in HBV strains from Chinese patients with occult hepatitis B.

    Science.gov (United States)

    Huang, Xiangyan; Ma, Chenyun; Zhang, Qiang; Shi, Qingfen; Huang, Tao; Liu, Chao; Li, Jie; Hollinger, F Blaine

    2017-10-01

    This study was designed to detect mutations that occur within the "a" determinant in the S gene of the hepatitis B virus (HBV) in patients with occult hepatitis B (OHB), and to analyze the influence of these mutations on expression and reactivity of the hepatitis B surface antigen (HBsAg). Twenty-three certified OHB samples were compared to 32 HBsAg positive samples from patients with chronic hepatitis B. The median HBV DNA levels in the OHB group were significantly lower than those in the control group (P determinant were analyzed by gene amplification and sequencing. This revealed mixed infections in which clones within a sample displayed either different mutations or mutations in association with clones that exhibited wild type amino acid patterns. Sequencing analysis also showed a significant difference between the proportions of amino acid mutations observed in the OHB and control groups. Seven recombinant S (rS) proteins with corresponding OHB mutations and three wild type alleles were expressed and purified in the Pichia pastoris expression system to preserve conformational attributes, and their reactivity analyzed using six commercial HBsAg assays. The OHB sera were HBsAg nonreactive while the rS proteins with corresponding OHB mutations were universally reactive. Thus, we postulate that the reduced binding affinity between mutated HBsAg and its antibody may not be as important in defining OHB as is the effect of specific mutations in the preS/S region of the genome that affect the synthesis and secretion of the S protein and/or the virion. © 2017 Wiley Periodicals, Inc.

  10. Prognostic implications of recipient or donor hepatitis B seropositivity in thoracic transplantation: analysis of 426 hepatitis B surface antigen-positive recipients.

    Science.gov (United States)

    Manickam, P; Krishnamoorthi, R; Kanaan, Z; Gunasekaran, P K; Cappell, M S

    2014-08-01

    Prognostic data on survival of hepatitis B surface antigen-positive (HBsAg+) recipients and of hepatitis B core antibody-positive (HBcAb+) donors are limited in the thoracic transplantation (TT) cohort. Improved understanding of risks could potentially expand the recipient and donor pools. Post-hoc analysis of limited-access dataset of the United Network for Organ Sharing database from January 2000-September 2010 was performed. Analyses were performed for all TT, including single and bilateral lung, orthotopic heart, and simultaneous heart-lung transplants. The primary analyzed outcome was overall survival. A Cox proportional multivariate hazards model was used to adjust for significant risk predictors. Of 24,817 patients included, 426 recipients were HBsAg+, of whom 106 (25%) died during a mean follow-up of 3.6 years. On multivariate analysis, recipient HBsAg+ (hazard ratio [HR] = 0.88, 95% confidence interval [CI]: 0.69-1.32; P = 0.80), and donor HBcAb+ (HR = 0.91, 95% CI: 0.68-1.22; P = 0.53) were not associated with increased overall mortality in the entire TT cohort, with similar results for each individual transplant cohort. Unadjusted survival analysis using Kaplan-Meier curves in individual transplant cohorts did not show significant differences between HBsAg+ and HBsAg- recipients. No statistically significant differences were found between causes of mortality in the 2 groups. HBsAg+ status of recipients or HBcAb+ status of donors does not significantly affect overall survival of TT recipients. These data add to the scant literature on this subject and could potentially increase the donor and recipient pools. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Seroclearance of hepatitis B surface antigen following hepatitis E exacerbation on chronic hepatitis E and B dual infection in a renal transplant recipient: a case report.

    Science.gov (United States)

    Yeh, Chau-Ting; Yeh, Christopher Sung-Huan; Chu, Yu-De; Chiang, Yang-Jen

    2018-02-28

    Hepatitis E virus infection usually causes an acute and self-resolving hepatitis. In areas where chronic hepatitis B virus infection is prevalent, acute hepatitis E virus superinfection on chronic hepatitis B virus infection occurs sporadically. In recent years, however, chronic hepatitis E virus infection has been recognized in patients under immunosuppressant therapy. To the best of our knowledge, cases involving patients with chronic hepatitis E virus and hepatitis B virus dual infection have never been reported. A 47-year-old Taiwanese woman who was a renal transplant recipient with chronic hepatitis B virus infection was under immunosuppressant and antiviral treatment. An episode of hepatitis B exacerbation developed due to withdrawal of antiviral treatment against advice, but the flare subsided following antiviral re-treatments. However, an episode of hepatitis exacerbation developed following removal of the renal graft because of graft failure. During the hepatitis flare, she was still under successful antiviral suppression against hepatitis B virus, while her serum samples were positive for hepatitis E virus RNA. Following the hepatitis flare, seroclearance of hepatitis B virus surface antigen developed. From then on, she was under regular hemodialysis. Five years later, another episode of mild hepatitis exacerbation occurred again with positive serum hepatitis E virus RNA. Tracing back the longitudinal serum samples, serum hepatitis E virus RNA was persistently positive throughout the course. This patient was thus recognized to have chronic hepatitis E virus and hepatitis B virus dual infection with intermittent hepatitis E exacerbations. In areas where chronic hepatitis B virus infection is prevalent, chronic hepatitis E virus coinfection can occur in organ transplant recipients receiving immunosuppressant. Intermittent hepatitis E exacerbations may develop, interfering with the status of hepatitis B virus infection.

  12. Development of anti-hepatitis B surface (HBs) antibodies after HBs antigen loss in HIV-hepatitis B virus co-infected patients.

    Science.gov (United States)

    Boyd, Anders; Canini, Laetitia; Gozlan, Joël; Lascoux-Combe, Caroline; Miailhes, Patrick; Fonquernie, Laurent; Girard, Pierre-Marie; Lacombe, Karine

    2017-10-01

    Hepatitis B surface antigen (HBsAg)-seroconversion, or loss of HBsAg and acquisition of anti-hepatitis B surface (HBs) antibodies, defines functional cure of chronic hepatitis B virus (HBV) infection. After HBsAg-loss, little is known regarding the development of anti-HBs antibodies and even less so in individuals co-infected with HIV. To determine anti-HBs antibody kinetics after HBsAg-loss and explore determinants of HBsAg-seroconversion in HIV-HBV co-infected patients. Patients enrolled in the French HIV-HBV cohort were included if they had >1 study visit after HBsAg-loss. Individual patient kinetics of anti-HBs antibody levels were modeled over time using mixed-effect non-linear regression, whereby maximum specific growth rate and maximal level of antibody production were estimated from a Gompertz growth equation. Fourteen (4.6%) of 308 co-infected patients followed in the cohort exhibited HBsAg-loss, all of whom were undergoing antiretroviral therapy. Nine (64.3%) of these patients achieved HBsAg-seroconversion during a median 3.0 years (IQR=1.1-5.1) after HBsAg-loss. Across individuals with HBsAg-seroconversion, the fastest rates of antibody growth ranged between 0.57-1.93year -1 (population maximum growth rate=1.02) and antibody production plateaued between 2.09-3.66 log 10 mIU/mL at the end of follow-up (population maximal antibody levels=2.66). Patients with HBsAg-seroconversion had substantial decreases in HBV DNA viral loads (P=0.03) and proportion with elevated ALT levels (P=0.02) and HBeAg-positive serology (P=0.08). No such differences were observed in those without HBsAg-seroconversion. Most co-infected patients with HBsAg-seroconversion produced and maintained stable antibody levels, yet kinetics of anti-HBs production were much slower compared to those observed post-vaccination or after clearance of acute HBV-infection. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Natural selection promotes antigenic evolvability.

    Science.gov (United States)

    Graves, Christopher J; Ros, Vera I D; Stevenson, Brian; Sniegowski, Paul D; Brisson, Dustin

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide an experimentally tractable system to test whether natural selection has favored mechanisms that increase evolvability. Many antigenic variation systems consist of paralogous unexpressed 'cassettes' that recombine into an expression site to rapidly alter the expressed protein. Importantly, the magnitude of antigenic change is a function of the genetic diversity among the unexpressed cassettes. Thus, evidence that selection favors among-cassette diversity is direct evidence that natural selection promotes antigenic evolvability. We used the Lyme disease bacterium, Borrelia burgdorferi, as a model to test the prediction that natural selection favors amino acid diversity among unexpressed vls cassettes and thereby promotes evolvability in a primary surface antigen, VlsE. The hypothesis that diversity among vls cassettes is favored by natural selection was supported in each B. burgdorferi strain analyzed using both classical (dN/dS ratios) and Bayesian population genetic analyses of genetic sequence data. This hypothesis was also supported by the conservation of highly mutable tandem-repeat structures across B. burgdorferi strains despite a near complete absence of sequence conservation. Diversification among vls cassettes due to natural selection and mutable repeat structures promotes long-term antigenic evolvability of VlsE. These findings provide a direct demonstration that molecular mechanisms that enhance evolvability of surface antigens are an evolutionary adaptation. The molecular evolutionary processes identified here can serve as a model for the evolution of antigenic evolvability in many pathogens which utilize similar strategies to establish chronic infections.

  14. Carcinoma-associated antigens

    International Nuclear Information System (INIS)

    Bartorelli, A.; Accinni, R.

    1981-01-01

    This invention relates to novel antigens associated with breast carcinoma, anti-sera specific to said antigens, 125 I-labeled forms of said antigens and methods of detecting said antigens in serum or plasma. The invention also relates to a diagnostic kit containing standardised antigens or antisera or marked forms thereof for the detection of said antigens in human blood, serum or plasma. (author)

  15. Dynamic interaction of /sup 111/indium-labeled monoclonal antibodies with surface antigens of solid tumors visualized in vivo by external scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, K.M.; Keenan, A.M.; Frincke, J.; David, G.; Pearson, J.; Oldham, R.K.; Morgan, A.C. Jr.

    1986-05-01

    Two /sup 111/indium-labeled murine monoclonal antibodies (MoAb), D3 and 9.2.27, directed to tumor antigens of L-10 hepatocarcinoma and human melanoma, respectively, selectively localized antigen-positive target cells in guinea pigs and nude mice. The fate of MoAb differed in the two antigen-antibody systems after reacting with their corresponding tumor antigens in vivo as reflected by patterns of distribution and turnover in vivo. The 9.2.27 localized in melanoma xenograft in nude mice after intravenous administration with slow loss from tumor but more rapid loss from normal tissues and thus demonstrated optimal imaging of small tumors (approximately equal to 5 mm) between 3 and 6 days after injection of the radiolabeled antibody. In contrast, D3 demonstrated a biphasic localization in guinea pig L-10 hepatocarcinoma with a maximal activity on the 2d day after administration and showed rapid loss from both tumor and normal tissues. Nonspecific localization of antibodies in liver and in kidney was found both in syngeneic (nude mice) and xenogeneic (guinea pig) hosts but was more pronounced in the xenogeneic species. These results indicate that the nature of the antigen-antibody interaction may be of importance in selecting MoAb for both diagnosis and therapy of malignant diseases.

  16. Characterization of sporozoite surface antigens of Plasmodium falciparum, using monoclonal antibodies. Part of a coordinated programme on the preparation of irradiated vaccines against some human diseases

    International Nuclear Information System (INIS)

    Groot, M.

    1982-10-01

    Sporozoites are considered as a source of potential vaccine. Characterization of their antigens is therefore important and can be achieved by monoclonal antibodies. The purpose of this project is to study the production of monoclonal antibodies against sporozoites of P. falciparum. Various infections of mosquitoes were carried out during the period 1981-1982 to obtain antigens for the production of hybridomas. Hybridomas were produced from mice immunized through the bites of infected mosquitoes and by intravenous inoculation. The anti-sporozoite activity of the hybridomas was tested by an immunofluorescent antibody test using P. falciparum sporozoites as antigens. Positive immunofluorescence was seen in hybridoma cell lines tested with P. falciparum, whereas negative results were obtained when the cell lines were cross-reacted with other human species (P. vivax) and with a rodent malaria parasite (P. berghei)

  17. Inhibition of Viability, Proliferation, Cytokines Secretion, Surface Antigen Expression, and Adipogenic and Osteogenic Differentiation of Adipose-Derived Stem Cells by Seven-Day Exposure to 0.5 T Static Magnetic Fields

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2016-01-01

    Full Text Available After seven-day exposure to 0.5-Tesla Static Magnetic Field (SMF, Adipose-derived Stem Cells (ASCs and those labeled by superparamagnetic iron oxide (SPIO nanoparticles were examined for viability by methyl thiazol tetrazolium (MTT assay, proliferation by cell counting and bromodeoxyuridine (BrdU incorporation, DNA integrity by single cell gel electrophoresis, surface antigen by flow cytometry analysis, and the expression of cytokines and genetic markers by reverse transcription-PCR and underwent adipogenic and osteogenic differentiation assessed by quantifying related specific genes expression. The SMF slightly reduced cell viability and proliferation and inhibited the expression of CD49d, CD54, and CD73 but did not damage DNA integrity. The SMF slightly downregulated the expression of cytokines including Vascular Endothelial Growth Factor (VEGF, Insulin-like Growth Factor-1 (IGF-1, Transforming Growth Factor Beta 1 (TGF-β1, genetic markers comprising Stem Cell Antigen-1 (Sca1, Octamer-4 (Oct-4, ATP-binding Cassette Subfamily B Member 1 (ABCB1, adipogenic marker genes containing Lipoprotein Lipase (LPL, Peroxisome Proliferator-Activated Receptor Gamma (PPAR-γ, and osteogenic marker genes including Secreted Phosphor-protein 1 (SPP1 and Osterix (OSX. Exposure to 0.5 T SMF for seven days inhibited viability, proliferation, surface antigen expression, cytokine secretion, stem cell genetic marker expression, and adipogenic and osteogenic differentiation but did not affect the DNA integrity in ASCs with or without SPIO labeling.

  18. Long-term effect of interferon plus ribavirin on hepatitis B surface antigen seroclearance in patients dually infected with hepatitis B and C viruses.

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    Ming-Lun Yeh

    Full Text Available BACKGROUND: Interferon-α/ribavirin combination therapy might promote hepatitis B surface antigen (HBsAg seroclearance in patients dually infected with hepatitis B and C viruses (HBV/HCV, but the long-term effect remains unclear. We aimed to investigate the rate of and the factors associated with HBsAg seroclearance during long-term follow-up after interferon-α/ribavirin combination therapy in HBV/HCV dually-infected patients. METHODOLOGY/PRINCIPAL FINDINGS: Eighty-one patients who received interferon-α/ribavirin combination therapy for 24 weeks with a follow-up period of >24 weeks were enrolled. HBV serological markers and HBV DNA were determined every 6 months. Early and late HBsAg seroclearance were defined as HBsAg loss in less or more than 6 months after end-of-treatment, respectively. Fifteen (18.5% patients had HBsAg seroclearance during a mean follow-up period of 3.4 (0.5-5.1 years. The 5-year cumulative incidence was 25.6%. Baseline cirrhosis and HBV DNA negativity 1 year after end-of-treatment were independently predictive of HBsAg seroclearance with an odds ratio (OR, 95% confidence intervals (CI of 16.6, 1.8-153 and 9.2, 1.4-62.1, respectively, by Cox regression hazard analysis. Four patients developed early and 11 developed late HBsAg seroclearance, respectively. Cox regression hazard analysis showed no factor was associated with early HBsAg seroclearance, whilst HBV DNA negativity 1 year after end-of-treatment was the only significant factor predicting late HBsAg loss (OR, 43.0; CI, 2.5-745. Five patients had HBsAg seroconversion with a 5-year cumulative incidence of 8.3%. HBV DNA negativity at baseline and one year after EOT had a trend for HBsAg seroconversion. HCV response did not correlate to HBsAg loss. CONCLUSIONS: We demonstrated that interferon-α/ribavirin had long-term effect on HBsAg seroclearance in dually HBV/HCV-infected patients. Baseline cirrhosis and seroclearance of HBV DNA 1 year after end-of-treatment were

  19. Dysregulated Response of Follicular Helper T cells to Hepatitis B Surface Antigen Promotes HBV Persistence in Mice and Associates With Outcomes of Patients.

    Science.gov (United States)

    Wang, Xiaowen; Dong, Qingyang; Li, Qian; Li, Yuanyuan; Zhao, Dianyuan; Sun, Jinjie; Fu, Junliang; Meng, Fanping; Lin, Hu; Luan, Junjie; Liu, Biao; Wang, Min; Wang, Fusheng; He, Fuchu; Tang, Li

    2018-03-12

    Production of neutralizing antibodies against hepatitis B surface antigen (HBsAg) is dysregulated in patients with persistent hepatitis V virus (HBV) infection. We investigated mechanisms by which this immune response to the virus is disrupted and whether it can be restored to promote clearance of HBV. Immune-competent C57BL/6N and C57BL/6J, as well as mice deficient in follicular helper T cells (Tfh cell-deficient), B cells, or Foxp3 + T-regulatory cells (Treg cell-deficient), were given hydrodynamic injections of pAAV/HBV1.2 plasmids. Some mice were given injections of sorted Tfh cells, pan-B cells, Treg cells, or a blocking antibody against CTLA4. Production of antibodies against HBsAg and clearance of HBV were assessed by flow cytometry, ELISA, PCR and immunohistochemical analyses. We obtained blood samples from patients with HBV infection and isolated Treg cells. We measured the ability of Treg cells to suppress production of interleukin 21 (IL21) in CD4 + T cells. Immune-competent C57BL/6N and C57BL/6J mice transfected with the plasmid encoding HBV had features of viral clearance and viral persistence observed in humans. A Tfh-cell response to HBsAg was required for clearance of HBV and was suppressed by Treg cells in mice with persistent HBV infection. Depletion of Treg cells or inhibition of Treg-cell function (with blocking antibody against CTLA4) restored the Tfh-cell response against HBsAg and clearance of HBV in mice. Impaired Tfh cell response to HBsAg was observed in blood from patients with chronic HBV infection, responsiveness was restored by depletion of Treg cells or blocking antibody against CTLA4. In studies of HBV-infected mice and blood from patients with chronic HBV infection, we found a Tfh-cell response to HBsAg of to be required for HBV clearance, and that this response was blocked by Treg cells. Inhibiting Treg cell activity using neutralizing antibody against CTLA4 restored the ability of Tfh cells to clear HBV infection; this approach

  20. Understanding early serum hepatitis D virus and hepatitis B surface antigen kinetics during pegylated interferon-alpha therapy via mathematical modeling.

    Science.gov (United States)

    Guedj, Jeremie; Rotman, Yaron; Cotler, Scott J; Koh, Christopher; Schmid, Peter; Albrecht, Jeff; Haynes-Williams, Vanessa; Liang, T Jake; Hoofnagle, Jay H; Heller, Theo; Dahari, Harel

    2014-12-01

    There is little information on the early kinetics of hepatitis delta virus (HDV) and hepatitis B surface antigen (HBsAg) during interferon-α therapy. Here a mathematical model was developed and fitted to frequent HDV and HBsAg kinetic data from 10 patients during the first 28 weeks of pegylated-interferon-α2a (peg-IFN) therapy. Three patients achieved a complete virological response (CVR), defined as undetectable HDV 6 months after treatment stopped with loss of HBsAg and anti-HBsAg seroconversion. After initiation of therapy, a median delay of 9 days (interquartile range [IQR]: 5-15) was observed with no significant changes in HDV level. Thereafter, HDV declined in a biphasic manner, where a rapid first phase lasting for 25 days (IQR: 23-58) was followed by a slower or plateau second phase. The model predicts that the main effect of peg-IFN is to reduce HDV production/release with a median effectiveness of 96% (IQR: 93-99.8). Median serum HDV half-life (t1/2 ) was estimated as 2.9 days (IQR: 1.5-5.3) corresponding to a pretreatment production and clearance of about 10(10) (IQR: 10(9.7) -10(10.7) ) virions/day. None of the patients with flat second phase in HDV achieved CVR. HBsAg kinetics of decline paralleled the second phase of HDV decline consistent with HBsAg-productive-infected cells being the main source of production of HDV, with a median t1/2 of 135 days (IQR: 20-460). The interferon lambda-3 polymorphism (rs12979860) was not associated with kinetic parameters. Modeling results provide insights into HDV-host dynamics, the relationship between serum HBsAg levels and HBsAg-infected cells, IFN's mode of action, and its effectiveness. The observation that a flat second phase in HDV and HBsAg kinetics was associated with failure to achieve CVR provides the basis to develop early stopping rules during peg-IFN treatment in HDV-infected patients. © 2014 by the American Association for the Study of Liver Diseases. This article has been contributed to by U

  1. Outcomes of liver transplantation in simultaneously hepatitis B surface antigen and hepatitis C virus RNA positive recipients: the deleterious effect of donor hepatitis B core antibody positivity.

    Science.gov (United States)

    Tandoi, F; Romagnoli, R; Martini, S; Mazza, E; Nada, E; Cocchis, D; Lupo, F; Salizzoni, M

    2012-09-01

    Recent data from Italian studies have shown excellent results of liver transplantation (LT) in hepatitis B virus (HBV)-infected patients with grafts from hepatitis B core antibody (HBcAb)-positive donors, whereas such grafts in hepatitis C virus (HCV)-infected recipients have displayed poorer outcomes. We investigated the results of LT with HBcAb-positive grafts in patients with ongoing HBV and HCV coinfections. From August 1999 to December 2009, we performed 27 adult primary LTs from deceased heart-beating donors into recipients showing hepatitis B surface antigen (HBsAg)- and HCV-RNA-positivity simultaneously: 12 patients received a graft from an HBsAg-negative HBcAb-positive donor (core+D group) and 15 from an HBcAb-negative donor (core-D group). Immunosuppression included a calcineurin inhibitor, antimetabolite and steroids which were suspended at 6 months. Anti-HBV prophylaxis was always perfomed with anti-HBs immunoglobulins and nucleos(t)idic analogues. The groups were similar regarding variables of donor, recipient, donor-recipient match, LT procedure, and acute rejection treatment. Median follow-up for surviving grafts was 67 months (range, 16-141). Among all patients, HCV-RNA remained positive after LT. The prevalence of histologically proven recurrent HCV hepatitis was similar in the 2 groups: 83% core+D vs 73% core-D. No recurrent HBV hepatitis occurred during the follow-up. Graft survival at 5 years was significantly lower in the core+D group (core+D 48% vs core-D 87%; P = .018), in which a significantly higher prevalence of graft loss was caused by HCV recurrence (core+D 5/12, 42% vs core-D 1/15, 7%; P = .03). All of the 5 core+D patients who lost their grafts due to HCV recurrence did not receive anti-HCV therapy (4 owing to an aggressive disease and 1 because of patient refusal). Outcomes of LT in patients with ongoing HBV and HCV coinfection are adversely affected by donor HBcAb positivity, an effect that is mainly mediated by the dismal course of

  2. Transplacentally acquired maternal antibody against hepatitis B surface antigen in infants and its influence on the response to hepatitis B vaccine.

    Directory of Open Access Journals (Sweden)

    Zhiqun Wang

    Full Text Available BACKGROUND: Passively acquired maternal antibodies in infants may inhibit active immune responses to vaccines. Whether maternal antibody against hepatitis B surface antigen (anti-HBs in infants may influence the long-term immunogenicity of hepatitis B vaccine remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: Totally 338 pairs of mothers and children were enrolled. All infants were routinely vaccinated against hepatitis B based on 0-, 1- and 6-month schedule. We characterized the transplacental transfer of maternal anti-HBs, and compared anti-HBs response in children of mothers with or without anti-HBs. In a prospective observation, all 63 anti-HBs positive mothers transferred anti-HBs to their infants; 84.1% of the infants had higher anti-HBs concentrations than their mothers. One and half years after vaccination with three doses of hepatitis B vaccine, the positive rate and geometric mean concentration (GMC of anti-HBs in 32 infants with maternal anti-HBs were comparable with those in 32 infants without maternal antibody (90.6% vs 87.5%, P = 0.688, and 74.5 vs 73.5 mIU/ml, P = 0.742, respectively. In a retrospective analysis, five and half years after vaccination with three doses vaccine, the positive rates of anti-HBs in 88 children of mothers with anti-HBs ≥1000 mIU/ml, 94 children of mothers with anti-HBs 10-999 mIU/ml, and 61 children of mothers with anti-HBs <10 mIU/ml were 72.7%, 69.2%, and 63.9% (P = 0.521, respectively; anti-HBs GMC in these three groups were 38.9, 43.9, and 31.7 mIU/ml (P = 0.726, respectively. CONCLUSIONS/SIGNIFICANCE: The data demonstrate that maternal anti-HBs in infants, even at high concentrations, does not inhibit the long-term immunogenicity of hepatitis B vaccine. Thus, current hepatitis B vaccination schedule for infants will be still effective in the future when most infants are positive for maternal anti-HBs due to the massive vaccination against hepatitis B.

  3. ANTIGENIC PROMOTION

    Science.gov (United States)

    Wu, Chin-Yu; Cinader, Bernard

    1971-01-01

    Rabbits were immunized with p-azobenzene arsonic acid derivatives of human serum albumin (HA-As) or of dissociated keyhole limpet hemocyanin. The IgM response to the hapten was evaluated in terms of the number of hapten-specific plaque-forming cells in the lymph node draining the injection site. In some experiments, antibody was measured by agglutination of tanned and sensitized erythrocytes. The hapten response of animals immunized with HA-As was increased (promoting effect) when the animals were injected with one of several structurally unrelated macromolecules: keyhole limpet hemocyanin (KLH), horse spleen ferritin (HSF), lysozyme (Lys), alum-precipitated human gamma globulin (alum-precipitated HGG). Different macromolecules differed in the magnitude of the promoting effect they induced, e.g., promotion by the associated form of KLH was greater than that by the dissociated form; alum-precipitated HGG was a better promoter than was soluble HGG. The relative magnitude of promotion by different macromolecules (associated vs. dissociated KLH, alum-precipitated vs. soluble HGG) correlated with the relative magnitude of the carrier effect, as judged by the hapten response induced by p-azobenzene arsonic acid conjugated to various proteins. Promotion was detected by agglutination assay of circulating antibody, by plaque assay of cells from the popliteal lymph node draining the site of preinjection, but not by plaque assay of cells from the contralateral lymph node. Promotion was dependent on the dose of the promoting macromolecule and on the dose of the hapten-protein conjugate. It was not observed in animals tolerant to the promoting macromolecule. Inhibition (i.e. antigenic competition), rather than promotion, was observed upon a secondary response to the preinjected macromolecule or when the hapten-protein conjugate was incorporated in Freund's adjuvant. PMID:15776570

  4. In vitro selection of Plasmodium falciparum 3D7 for expression of variant surface antigens associated with severe malaria in African children

    DEFF Research Database (Denmark)

    Staalsoe, Trine; Nielsen, Morten A; Vestergaard, Lasse S

    2003-01-01

    P. falciparum-infected red blood cells (IRBC) can adhere to endothelial host receptors through parasite-encoded, clonally variant surface antigens (VSA). The VSA-mediated IRBC adhesion and the acquired VSA-specific antibody response have both been linked to IRBC organ tropism and disease severity....... Parasites isolated from young children with severe malaria (SM) tend to express a limited and conserved set of VSA (VSASM) that are both stronger and more commonly recognized by IgG in the plasma of malaria-exposed individuals than VSA (VSAUM) expressed by parasites causing uncomplicated malaria (UM...... identification of VSASM-encoding genes in 3D7, we report here a method of enforcing expression of VSASM-like antigens in this parasite clone by a novel selection method using plasma from semi-immune children with low VSAUM-specific, but high VSASM-specific, IgG reactivity. In addition to the resulting increase...

  5. Virosomes for antigen and DNA delivery

    NARCIS (Netherlands)

    Daemen, T; de Mare, A; Bungener, L; de Jonge, J; Huckriede, A; Wilschut, J

    2005-01-01

    Specific targeting and delivery as well as the display of antigens on the surface of professional antigen-presenting cells (APCs) are key issues in the design and development of new-generation vaccines aimed at the induction of both humoral and cell-mediated immunity. Prophylactic vaccination

  6. The quantity and quality of African children's IgG responses to merozoite surface antigens reflect protection against Plasmodium falciparum malaria.

    NARCIS (Netherlands)

    Courtin, D.; Oesterholt, M.J.A.M.; Huismans, H.; Kusi, K.; Milet, J.; Badaut, C.; Gaye, O.; Roeffen, W.F.G.; Remarque, E.J.; Sauerwein, R.W.; Garcia, A.; Luty, A.J.F.

    2009-01-01

    BACKGROUND: Antibodies, particularly cytophilic IgG subclasses, with specificity for asexual blood stage antigens of Plasmodium falciparum, are thought to play an important role in acquired immunity to malaria. Evaluating such responses in longitudinal sero-epidemiological field studies, allied to

  7. Safety of currently licensed hepatitis B surface antigen vaccines in the United States, Vaccine Adverse Event Reporting System (VAERS), 2005-2015.

    Science.gov (United States)

    Haber, Penina; Moro, Pedro L; Ng, Carmen; Lewis, Paige W; Hibbs, Beth; Schillie, Sarah F; Nelson, Noele P; Li, Rongxia; Stewart, Brock; Cano, Maria V

    2018-01-25

    Currently four recombinant hepatitis B (HepB) vaccines are in use in the United States. HepB vaccines are recommended for infants, children and adults. We assessed adverse events (AEs) following HepB vaccines reported to the Vaccine Adverse Event Reporting System (VAERS), a national spontaneous reporting system. We searched VAERS for reports of AEs following single antigen HepB vaccine and HepB-containing vaccines (either given alone or with other vaccines), from January 2005 - December 2015. We conducted descriptive analyses and performed empirical Bayesian data mining to assess disproportionate reporting. We reviewed serious reports including reports of special interest. VAERS received 20,231 reports following HepB or HepB-containing vaccines: 10,291 (51%) in persons 18 years; for 1485 (7.3%) age was missing. Dizziness and nausea (8.4% each) were the most frequently reported AEs following a single antigen HepB vaccine: fever (23%) and injection site erythema (11%) were most frequent following Hep-containing vaccines. Of the 4444 (22%) reports after single antigen HepB vaccine, 303 (6.8%) were serious, including 45 deaths. Most commonly reported cause of death was Sudden Infant Death Syndrome (197). Most common non-death serious reports following single antigen HepB vaccines among infants aged 18 years. Most common vaccination error following single antigen HepB was incorrect product storage. Review current U.S.-licensed HepB vaccines administered alone or in combination with other vaccines did not reveal new or unexpected safety concerns. Vaccination errors were identified which indicate the need for training and education of providers on HepB vaccine indications and recommendations. Published by Elsevier Ltd.

  8. Identification and characterization of new Leishmania promastigote surface antigens, LaPSA-38S and LiPSA-50S, as major immunodominant excreted/secreted components of L. amazonensis and L. infantum.

    Science.gov (United States)

    Bras-Gonçalves, Rachel; Petitdidier, Elodie; Pagniez, Julie; Veyrier, Renaud; Cibrelus, Prisca; Cavaleyra, Mireille; Maquaire, Sarah; Moreaux, Jérôme; Lemesre, Jean-Loup

    2014-06-01

    We have previously demonstrated that sera from dogs vaccinated with excreted/secreted antigens (ESA) of Leishmania infantum promastigotes (LiESAp) mainly recognized an immunodominant antigen of 54 kDa. An anti-LiESAp-specific IgG2 humoral response was observed and associated to Th1-type response in vaccinated dogs. This response was highly correlated with a long-lasting and strong LiESAp-vaccine protection toward L. infantum experimental infection. In addition, it was also shown that dogs from the vaccinated group developed a selective IgG2 response against an immunodominant antigen of 45 kDa of Leishmania amazonensis ESA promastigotes (LaESAp). In order to identify and characterize these immunodominant antigens, a mouse monoclonal antibody (mAb F5) was produced by immunization against LaESAp. It was found to recognize the major antigenic targets of both LaESAp and LiESAp. Analysis with mAb F5 of L. amazonensis amastigote and promastigote cDNA expression libraries enabled the identification of clones encoding proteins with significant structural homology to the promastigote surface antigens named PSA-2/gp-46. Among them, one clone presented a full-length cDNA and encoded a novel L. amazonensis protein of 38.6 kDa calculated molecular mass (LaPSA-38S) sharing an amino acid sequence consistent with that of the PSA polymorphic family and a N-terminal signal peptide, characteristic of a secreted protein. We then screened a L. infantum promastigote DNA cosmid library using a cDNA probe derived from the LaPSA-38S gene and identified a full-length clone of a novel excreted/secreted protein of L. infantum with a calculated molecular mass of 49.2 kDa and named LiPSA-50S. The fact that a significant immunological reactivity was observed against PSA, suggests that these newly identified proteins could have an important immunoregulatory influence on the immune response. This hypothesis is supported by the fact that (i) these proteins were naturally excreted/secreted by viable

  9. Complexes of Streptavidin-Fused Antigens with Biotinylated Antibodies Targeting Receptors on Dendritic Cell Surface: A Novel Tool for Induction of Specific T-Cell Immune Responses

    Czech Academy of Sciences Publication Activity Database

    Staněk, Ondřej; Linhartová, Irena; Majlessi, L.; Leclerc, C.; Šebo, Peter

    2012-01-01

    Roč. 51, č. 3 (2012), s. 221-232 ISSN 1073-6085 R&D Projects: GA AV ČR KAN200520702; GA ČR GA310/08/0447; GA MŠk 2B06161 Institutional research plan: CEZ:AV0Z50200510 Keywords : Streptavidin * Antigen delivery * Biotinylated antibody Subject RIV: EE - Microbiology, Virology Impact factor: 2.262, year: 2012

  10. Physiological response of Pichia pastoris GS115 to methanol-induced high level production of the Hepatitis B surface antigen: catabolic adaptation, stress responses, and autophagic processes.

    Science.gov (United States)

    Vanz, Ana Leticia; Lünsdorf, Heinrich; Adnan, Ahmad; Nimtz, Manfred; Gurramkonda, Chandrasekhar; Khanna, Navin; Rinas, Ursula

    2012-08-08

    Pichia pastoris is an established eukaryotic host for the production of recombinant proteins. Most often, protein production is under the control of the strong methanol-inducible aox1 promoter. However, detailed information about the physiological alterations in P. pastoris accompanying the shift from growth on glycerol to methanol-induced protein production under industrial relevant conditions is missing. Here, we provide an analysis of the physiological response of P. pastoris GS115 to methanol-induced high-level production of the Hepatitis B virus surface antigen (HBsAg). High product titers and the retention of the protein in the endoplasmic reticulum (ER) are supposedly of major impact on the host physiology. For a more detailed understanding of the cellular response to methanol-induced HBsAg production, the time-dependent changes in the yeast proteome and ultrastructural cell morphology were analyzed during the production process. The shift from growth on glycerol to growth and HBsAg production on methanol was accompanied by a drastic change in the yeast proteome. In particular, enzymes from the methanol dissimilation pathway started to dominate the proteome while enzymes from the methanol assimilation pathway, e.g. the transketolase DAS1, increased only moderately. The majority of methanol was metabolized via the energy generating dissimilatory pathway leading to a corresponding increase in mitochondrial size and numbers. The methanol-metabolism related generation of reactive oxygen species induced a pronounced oxidative stress response (e.g. strong increase of the peroxiredoxin PMP20). Moreover, the accumulation of HBsAg in the ER resulted in the induction of the unfolded protein response (e.g. strong increase of the ER-resident disulfide isomerase, PDI) and the ER associated degradation (ERAD) pathway (e.g. increase of two cytosolic chaperones and members of the AAA ATPase superfamily) indicating that potential degradation of HBsAg could proceed via the

  11. Impact of the thimerosal controversy on hepatitis B vaccine coverage of infants born to women of unknown hepatitis B surface antigen status in Michigan.

    Science.gov (United States)

    Biroscak, Brian J; Fiore, Anthony E; Fasano, Nancy; Fineis, Patrick; Collins, Michael P; Stoltman, Gillian

    2003-06-01

    Hepatitis B vaccine is recommended for all infants, and the series may be started during the delivery admission. For infants who are born either to women who are positive for hepatitis B surface antigen (HBsAg) or to women whose HBsAg status is unknown, vaccination should be started within 12 hours of birth to prevent perinatal and early childhood hepatitis B virus infection. Because of concerns about mercury exposures from vaccines that contain thimerosal, the United States Public Health Service (USPHS) and the American Academy of Pediatrics (AAP) recommended in July 1999 that the first dose of hepatitis B vaccine be deferred until 2-6 months of age but only for infants who are born to HBsAg-negative women. To assess the impact on birth-dose vaccine coverage for infants who are born to women with unknown HBsAg status, we measured coverage before and after July 1999. A sample of Michigan infants who were born to women whose HBsAg status was either unknown or missing were identified by reviewing newborn screening cards for infants who were born during 1) March-April 1999 (before recommendation changes [T1]); 2) July 15-September 15, 1999 (immediately after recommendation changes [T2]); and 3) March-April 2000 (6 months after resumption of pre-1999 practices were recommended [T3]). We verified maternal HBsAg screening and newborn hepatitis B vaccination by reviewing infant and maternal hospital records. Of 1201 infants who were born to women whose HBsAg status was indicated as unknown or missing on the newborn screening card during the 3 time periods, 216 (18%) were born to women whose status was truly unknown at the time of delivery, as determined by medical record review. During T1, 53% of these 216 infants received hepatitis B vaccine before hospital discharge, compared with 7% of infants who were born during T2 and 57% of infants who were born during T3. During T1, 19% of these infants received hepatitis B vaccine within 12 hours of birth compared with 1% of

  12. Physiological response of Pichia pastoris GS115 to methanol-induced high level production of the Hepatitis B surface antigen: catabolic adaptation, stress responses, and autophagic processes

    Science.gov (United States)

    2012-01-01

    Background Pichia pastoris is an established eukaryotic host for the production of recombinant proteins. Most often, protein production is under the control of the strong methanol-inducible aox1 promoter. However, detailed information about the physiological alterations in P. pastoris accompanying the shift from growth on glycerol to methanol-induced protein production under industrial relevant conditions is missing. Here, we provide an analysis of the physiological response of P. pastoris GS115 to methanol-induced high-level production of the Hepatitis B virus surface antigen (HBsAg). High product titers and the retention of the protein in the endoplasmic reticulum (ER) are supposedly of major impact on the host physiology. For a more detailed understanding of the cellular response to methanol-induced HBsAg production, the time-dependent changes in the yeast proteome and ultrastructural cell morphology were analyzed during the production process. Results The shift from growth on glycerol to growth and HBsAg production on methanol was accompanied by a drastic change in the yeast proteome. In particular, enzymes from the methanol dissimilation pathway started to dominate the proteome while enzymes from the methanol assimilation pathway, e.g. the transketolase DAS1, increased only moderately. The majority of methanol was metabolized via the energy generating dissimilatory pathway leading to a corresponding increase in mitochondrial size and numbers. The methanol-metabolism related generation of reactive oxygen species induced a pronounced oxidative stress response (e.g. strong increase of the peroxiredoxin PMP20). Moreover, the accumulation of HBsAg in the ER resulted in the induction of the unfolded protein response (e.g. strong increase of the ER-resident disulfide isomerase, PDI) and the ER associated degradation (ERAD) pathway (e.g. increase of two cytosolic chaperones and members of the AAA ATPase superfamily) indicating that potential degradation of HBsAg could

  13. Cell-surface expression of neuron-glial antigen 2 (NG2) and melanoma cell adhesion molecule (CD146) in heterogeneous cultures of marrow-derived mesenchymal stem cells.

    Science.gov (United States)

    Russell, Katie C; Tucker, H Alan; Bunnell, Bruce A; Andreeff, Michael; Schober, Wendy; Gaynor, Andrew S; Strickler, Karen L; Lin, Shuwen; Lacey, Michelle R; O'Connor, Kim C

    2013-10-01

    Cellular heterogeneity of mesenchymal stem cells (MSCs) impedes their use in regenerative medicine. The objective of this research is to identify potential biomarkers for the enrichment of progenitors from heterogeneous MSC cultures. To this end, the present study examines variation in expression of neuron-glial antigen 2 (NG2) and melanoma cell adhesion molecule (CD146) on the surface of MSCs derived from human bone marrow in response to culture conditions and among cell populations. Multipotent cells isolated from heterogeneous MSC cultures exhibit a greater than three-fold increase in surface expression for NG2 and greater than two-fold increase for CD146 as compared with parental and lineage-committed MSCs. For both antigens, surface expression is downregulated by greater than or equal to six-fold when MSCs become confluent. During serial passage, maximum surface expression of NG2 and CD146 is associated with minimum doubling time. Upregulation of NG2 and CD146 during loss of adipogenic potential at early passage suggests some limits to their utility as potency markers. A potential relationship between proliferation and antigen expression was explored by sorting heterogeneous MSCs into rapidly and slowly dividing groups. Fluorescence-activated cell sorting revealed that rapidly dividing MSCs display lower scatter and 50% higher NG2 surface expression than slowly dividing cells, but CD146 expression is comparable in both groups. Heterogeneous MSCs were sorted based on scatter properties and surface expression of NG2 and CD146 into high (HI) and low (LO) groups. Sc(LO)NG2(HI) and Sc(LO)NG2(HI)CD146(HI) MSCs have the highest proliferative potential of the sorted groups, with colony-forming efficiencies that are 1.5-2.2 times the value for the parental controls. The Sc(LO) gate enriches for rapidly dividing cells. Addition of the NG2(HI) gate increases cell survival to 1.5 times the parental control. Further addition of the CD146(HI) gate does not significantly

  14. Coexistence of hepatitis B surface antigen and antibody to hepatitis B surface may increase the risk of hepatocellular carcinoma in chronic hepatitis B virus infection: a retrospective cohort study.

    Science.gov (United States)

    Seo, Seung In; Choi, Hyeok Soo; Choi, Bo Youn; Kim, Hyoung Su; Kim, Hak Yang; Jang, Myoung Kuk

    2014-01-01

    The simultaneous detection of hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface (anti-HBs) is unusual in chronic hepatitis B virus (HBV) infection, but may be related with more advanced liver diseases. This retrospective long-term cohort study was aimed to investigate whether coexistence of HBsAg and anti-HBs may increase the risk of hepatocellular carcinoma (HCC) in chronic HBV infection. A total of 1,042 non-HCC patients were recruited and followed up for a median 4.3 years (range 1.0-22 years). Univariate and multivariate analyses were performed to identify the risk factors for HCC development. The prevalence of coexistence of HBsAg and anti-HBs was 7.0% (73/1,042). In univariate analysis, the 5-, 10-, and 15-year cumulative incidences of HCC were significantly higher in coexistence group than in HBsAg only group (12.7%, 23.4%, 69.4% vs. 4.9%, 13%, 20.6%, respectively; P = 0.008). In multivariate analysis, coexistence of HBsAg and anti-HBs [Hazard ratio (HR), 2.001; 95% confidence interval (CI), 1.023-3.912; P = 0.043] as well as male gender [HR, 1.898; 95% CI, 0.31-0.896; P = 0.018], age over 40 years [HR, 14.56; 95% CI, 4.499-47.08; P = 0.0001], and cirrhosis [HR, 7.995; 95% CI, 4.756-13.439; P = 0.0001] was identified as the independent factor for HCC development. Also, the cumulative incidence of HCC increased in proportion to the number of the risk factors. In conclusion, coexistence of HBsAg and anti-HBs may increase independently the risk of HCC development in chronic HBV infection. Therefore, consideration of HCC development is required in patients with coexistence of HBsAg and anti-HBs. © 2013 Wiley Periodicals, Inc.

  15. Quantitation of MHC antigen expression on colorectal tumours and its association with tumour progression.

    OpenAIRE

    Durrant, L. G.; Ballantyne, K. C.; Armitage, N. C.; Robins, R. A.; Marksman, R.; Hardcastle, J. D.; Baldwin, R. W.

    1987-01-01

    A flow cytometric technique has been established for accurately quantitating the cell surface density of MHC antigens and the percentage of cells expressing MHC antigens in 38 colorectal tumours. Thirty-four percent of tumours were partially or completely negative for HLA-ABC antigen expression. Although the quantity of HLA-ABC antigens varied widely, there was no correlation between the density of HLA-ABC antigens, or the percentage of cells expressing these antigens and clinicopathological ...

  16. Comparison of the binding properties of the mushroom Marasmius oreades lectin and Griffonia simplicifolia I-B isolectin to alphagalactosyl carbohydrate antigens in the surface phase

    DEFF Research Database (Denmark)

    Kirkeby, Svend; Winter, Harry C; Goldstein, Irwin J

    2004-01-01

    and laminin from basement membrane of mouse sarcoma that contains the xenogenic Galalpha1-3Gal1-4GlcNAc epitope were immobilized in microtiter plate wells and lectin binding determined with an enzyme-linked assay. After 24 h of incubation, MOA had higher affinity for the xenogenic pentasaccharide (Galalpha1....... The results indicate that the Marasmius oreades lectin has nearly the same affinities as does GS I-B(4) for the simple xenogenic carbohydrate antigens, but MOA has greater affinity for the pentasaccharide and is far more specific in its binding preferences than the Griffonia lectin....

  17. Crystallization and preliminary X-ray diffraction analysis of PsaA, the adhesive pilin subunit that forms the pH 6 antigen on the surface of Yersinia pestis

    International Nuclear Information System (INIS)

    Bao, Rui; Esser, Lothar; Sadhukhan, Annapurna; Nair, Manoj K. M.; Schifferli, Dieter M.; Xia, Di

    2012-01-01

    The pH 6 antigen Psa displayed on the surface of Yersinia pestis, the bacterium that causes plague in humans, consists of polymers of a single protein subunit termed PsaA. Donor-strand complemented PsaA was purified and crystallized. Yersinia pestis has been responsible for a number of high-mortality epidemics throughout human history. Like all other bacterial infections, the pathogenesis of Y. pestis begins with the attachment of bacteria to the surface of host cells. At least five surface proteins from Y. pestis have been shown to interact with host cells. Psa, the pH 6 antigen, is one of them and is deployed on the surface of bacteria as thin flexible fibrils that are the result of the polymerization of a single PsaA pilin subunit. Here, the crystallization of recombinant donor-strand complemented PsaA by the hanging-drop vapor-diffusion method is reported. X-ray diffraction data sets were collected to 1.9 Å resolution from a native crystal and to 1.5 Å resolution from a bromide-derivatized crystal. These crystals displayed the symmetry of the orthorhombic space group P222 1 , with unit-cell parameters a = 26.3, b = 54.6, c = 102.1 Å. Initial phases were derived from single isomorphous replacement with anomalous scattering experiments, resulting in an electron-density map that showed a single molecule in the crystallographic asymmetric unit. Sequence assignment was aided by residues binding to bromide ions of the heavy-atom derivative

  18. Facts on the fragmentation of antigens in presenting cells, on the association of antigen fragments with MHC molecules in cell-free systems, and speculation on the cell biology of antigen processing

    DEFF Research Database (Denmark)

    Werdelin, O; Mouritsen, S; Petersen, B L

    1988-01-01

    The processing of a protein antigen is a multi-step event taking place in antigen-presenting cells. Processing is a prerequisite for the recognition of most antigens by T lymphocytes. The antigen is ingested by endocytosis, transported to an acid cellular compartment and subjected to proteolytic...... fragmentation. Some of the antigen fragments bind to MHC class II molecules and are transported to the surface of the antigen-presenting cell where the actual presentation to T lymphocytes occurs. The nature of the processed antigen, how and where it is derived and subsequently becomes associated with MHC...

  19. Long-term real-world entecavir therapy in treatment-naïve hepatitis B patients: base-line hepatitis B virus DNA and hepatitis B surface antigen levels predict virologic response.

    Science.gov (United States)

    Cho, Ju-Yeon; Sohn, Won; Sinn, Dong-Hyun; Gwak, Geum-Youn; Paik, Yong-Han; Choi, Moon Seok; Koh, Kwang Cheol; Paik, Seung Woon; Yoo, Byung Chul; Lee, Joon Hyeok

    2017-07-01

    Entecavir is a potent nucleoside analogue with high efficacy and barrier for resistance. We aimed to investigate the long-term efficacy and viral resistance rate of entecavir and explore the factors associated with virologic response, including quantitative hepatitis B surface antigen (qHBsAg) levels. One thousand and nine treatment-naïve chronic hepatitis B (CHB) patients were evaluated for cumulative rates of virologic response, biochemical response, and entecavir mutations. The role of baseline qHBsAg for virologic response was assessed in 271 patients with qHBsAg prior to entecavir treatment. The median duration of entecavir treatment was 26.5 months. The cumulative rate of virologic response at years 1, 3, and 5 were 79.0%, 95.6%, and 99.4%, respectively. The cumulative rate of entecavir resistance was 1.0% and 2.1% in years 3 and 5. Multivariate analysis identified baseline hepatitis B e antigen (HBeAg) negative status ( p response. Lower qHBsAg was an independent predictor of virologic response in patients with baseline qHBsAg. There were no serious adverse events during treatment. Long-term entecavir treatment of nucleos(t)ide-naïve CHB patients was associated with an excellent virologic response and a low rate of entecavir-resistant mutations at 5 years. Baseline HBV DNA load, qHBsAg levels, and HBeAg status were predictors of virologic response during entecavir treatment.

  20. Rapid detection and semi-quantification of IgG-accessible Staphylococcus aureus surface-associated antigens using a multiplex competitive Luminex assay

    NARCIS (Netherlands)

    Hansenova Manaskova, S.; Bikker, F.J.; Veerman, E.C.I.; van Belkum, A.; van Wamel, W.J.B.

    2013-01-01

    The surface characterization of Staphylococcus aureus is currently labor intensive and time consuming. Therefore, we developed a novel method for the rapid yet comprehensive characterization of S. aureus cell-surface-associated proteins and carbohydrates, based on a competitive Luminex assay. In

  1. AntigenMap 3D: an online antigenic cartography resource.

    Science.gov (United States)

    Barnett, J Lamar; Yang, Jialiang; Cai, Zhipeng; Zhang, Tong; Wan, Xiu-Feng

    2012-05-01

    Antigenic cartography is a useful technique to visualize and minimize errors in immunological data by projecting antigens to 2D or 3D cartography. However, a 2D cartography may not be sufficient to capture the antigenic relationship from high-dimensional immunological data. AntigenMap 3D presents an online, interactive, and robust 3D antigenic cartography construction and visualization resource. AntigenMap 3D can be applied to identify antigenic variants and vaccine strain candidates for pathogens with rapid antigenic variations, such as influenza A virus. http://sysbio.cvm.msstate.edu/AntigenMap3D

  2. Antigens of Streptococcus sanguis

    Science.gov (United States)

    Rosan, Burton

    1973-01-01

    An antigenic analysis of the alpha-hemolytic streptococci isolated from dental plaque was performed by use of antisera against a strain of Streptococcus sanguis (M-5) which was isolated from dental plaque. Immunoelectrophoretic and Ouchterlony tests of Rantz and Randall extracts of 45 strains gave positive reactions with the M-5 antisera. These strains represented 60% of the strains tested. The number of antigens which could be identified in these extracts varied from one to five and were designated a to e. The a antigen was found in 36 of the strains tested, including reference strains of S. sanguis and the group H streptococci. The strains reacting with the M-5 antisera were divided into two majors types: type I consisted of 23 strains in which the a antigen was found alone or with one or more of the c, d, and e antigens; type II consisted of 13 strains in which both the a and b antigens were found with or without one or more of the c, d, and e antigens. The remaining strains contained, either singly or in combination, the b, c, d, and e antigens but not the a antigen. Biochemical tests of representatives of each serotype and reference strains indicated that strains reacting with M-5 antisera were S. sanguis. These findings suggest that S. sanguis strains share common physiological and serological properties. Images PMID:4633291

  3. Prevalence and chemotherapy-induced reactivation of occult hepatitis B virus among hepatitis B surface antigen negative patients with diffuse large B-cell lymphoma: Significance of hepatitis B core antibodies screening

    International Nuclear Information System (INIS)

    Elbedewy, T.A.; Elashtokhy, H.A.; Rabee, E.S.; Kheder, G.E.

    2015-01-01

    Background: Occult hepatitis B infection (OBI) is characterized by negative hepatitis B surface antigen (HBsAg) and detectable hepatitis B virus (HBV)-DNA in the liver and/or serum, with or without hepatitis B core antibody (anti-HBc). Anti-HBc is the most sensitive marker of previous HBV. HBV reactivation in patients under immunosuppressive treatment is life-threatening, occurring in both overt and occult HBV especially in hematological malignancies. Aim of the work: To evaluate the prevalence and chemotherapy-induced reactivation of OBI among hepatitis B surface antigen negative patients with diffuse large B-cell lymphoma (DLBCL) patients and to determine the significance of anti-HBc screening among this group of patients before receiving chemotherapy. Patients and methods: This cross-sectional study included 72 DLBCL patients negative for HBsAg, HBsAb and hepatitis C virus antibodies (anti-HCV). Patients were subjected to investigations including anti-HBc. All patients underwent alanine transaminase (ALT) monitoring before each cycle of chemotherapy and monthly for 12 months after the end of chemotherapy. Patients with suspected OBI were tested for HBV-DNA using real-time polymerase chain reaction (PCR). Results: Anti-HBc was detected in 10 of 72 HBsAg negative sera (13.89%) (95% confidence interval 6.9-22.2%). Five of the 10 anti-HBc positive patients in this study had OBI reactivation. Conclusion: The study concluded that anti-HBc screening is mandatory before chemotherapy. HBsAg-negative/anti-HBc-positive patients should be closely observed for signs of HBV reactivation through the regular monitoring of ALT. Prophylaxis lamivudine is recommended for anti-HBc positive patients before chemotherapy.

  4. Effects of irradiation, glucocorticoid and FK506 on cell-surface antigen expression by rat thymocytes: a three-colour flow cytofluorometric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchida, M.; Konishi, M.; Takai, K.; Naito, K.; Fujikura, Y.; Fukumoto, T. (Yamaguchi Univ. (Japan). School of Medicine)

    1994-11-01

    The expression of T-cell antigen receptor (TCR) [alpha][beta] was investigated in rat CD4[sup -]CD8[sup -] thymocytes during thymic reconstitution after the exposure of animals to irradiation or glucocorticoid. The effect of the immunosuppressant FK506 on the expression of TCR[alpha][beta] in rat CD4[sup -]CD8[sup -] thymocytes was also examined. The percentage of CD4[sup -]CD8[sup -] thymocytes constituted 2.6% of total thymocytes and that of CD4[sup -]CD8[sup -]TCR[alpha][beta][sup high] cells constituted 12.6% of CD4[sup -]CD8[sup -]thymocytes in normal adult Lewis rats. The percentage of CD4[sup -]CD8[sup -] TCR[alpha][beta][sup high] cells increased during thymic reconstitution after irradiation, and maximally constituted 28.6% of CD4[sup -]CD8[sup -] thymocytes on day 7. Similar results were obtained during thymic reconstitution after glucocorticoid treatment. In contrast, continuous treatment with FK506 for 7 days markedly decreased not only the percentages of CD4[sup +]CD8[sup -]TCR[alpha][beta][sup high] and CD4[sup -]CD8[sup +] TCR[alpha][beta][sup high] thymocytes, but also that of CD4[sup -]CD8[sup -] TCR[alpha][beta][sup high] thymocytes. These results indicate that rat CD4[sup -]CD8[sup -] thymocytes contain a subpopulation of mature (TCR[alpha][beta][sup high]) cells. The possible implications of the existence of this subpopulation with regard to thymocyte differentiation and maturation are discussed. (author).

  5. Adenovirus 5 and 35 vectors expressing Plasmodium falciparum circumsporozoite surface protein elicit potent antigen-specific cellular IFN-gamma and antibody responses in mice

    NARCIS (Netherlands)

    Shott, Joseph P.; McGrath, Shannon M.; Pau, Maria Grazia; Custers, Jerome H. V.; Ophorst, Olga; Demoitié, Marie-Ange; Dubois, Marie-Claude; Komisar, Jack; Cobb, Michelle; Kester, Kent E.; Dubois, Patrice; Cohen, Joe; Goudsmit, Jaap; Heppner, D. Gray; Stewart, V. Ann

    2008-01-01

    Falciparum malaria vaccine candidates have been developed using recombinant, replication-deficient serotype 5 and 35 adenoviruses (Ad5, Ad35) encoding the Plasmodium falciparum circumsporozoite surface protein (CSP) (Ad5.CS, Ad35.CS) (Crucell Holland BV, Leiden, The Netherlands). To evaluate the

  6. Eosinofil Sel Penyaji Antigen

    Directory of Open Access Journals (Sweden)

    Safari Wahyu Jatmiko

    2015-04-01

    Full Text Available Sel eosinofil merupakan jenis sel lekosit yang terlibat dalam berbagai patogenesis penyakit. Sel eosinofil pada awalnya dikenal sebagai sel efektor  dari sistem imunitas alamiah. Akan tetapi, kemampuan sel eosinofil dalam memfagositosis patogen menimbulkan dugaan bahwa sel eosinofil ikut berperan sebagai sel penyaji antigen. Hal ini dianalogikan dengan sel makrofag dan sel dendritik yang bisa memfagositosis dan menyajikan antigen sebagai hasil dari degradasi patogen yang difagositosis. Untuk menjawab permasalahan ini, penulis melakukan penelusuran artikel tentang eosinofil sebagai sel penyaji antigen melalui US National Library of Medicine National Institute of Healthdengan kata kunci eoshinophil dan antigen presenting cell. Hasil penelusuran adalah ditemukannya 10 artikel yang relevan dengan topik. Hasil dari sintesis kesepuluh jurnal tersebut adalah sel eosinofil mampu berperan sebagai sel penyaji antigen yang profesional (professionalantigenpresentng cell

  7. Expression of Hepatitis B virus surface antigen (HBsAg from genotypes A, D and F and influence of amino acid variations related or not to genotypes on HBsAg detection

    Directory of Open Access Journals (Sweden)

    Natalia M. Araujo

    Full Text Available The impact of hepatitis B virus (HBV genotypes on the sensitivity of surface antigen (HBsAg detection assays has been poorly investigated. Here, plasmids carrying consensus or variant coding sequences for HBV surface proteins from genotypes A, D and F, were constructed. HBsAg levels were evaluated in medium and extracts of transfected CHO cells by a commercial polyclonal-based assay. We show that HBsAg detection values of consensus forms from genotypes D and F were, respectively, 37% and 30% lower than those obtained by genotype A. However, the presence of two single variations, T143M in genotype A, and T125M in genotype D, produced a decrease of 44% and an increase of 34%, respectively, on HBsAg mean values in comparison with their consensus forms. In conclusion, HBsAg detection levels varied among HBV genotypes. However, unique amino acid substitutions not linked to genotypes, such as T125M and T143M described here, should have more implications in HBV immunological diagnostics than the set of variations characteristic of each HBV genotype.

  8. Simultaneous expression of growth hormone releasing hormone (GHRH) and hepatitis B surface antigen/somatostatin (HBsAg/SS) fusion genes in a construct in the skeletal muscle enhances rabbit weight gain.

    Science.gov (United States)

    Dai, Jian-wei; Liu, Song-cai; Hao, Lin-lin; Zhang, Yong-liang; Zhang, Qianqian; Ren, Xiao-hui; Jiang, Qing-yan

    2008-01-01

    Somatostatin (SS) and growth hormone-releasing hormone (GHRH) are synthesized and secreted by the hypothalamus, which can control the synthesis and secretion of the growth hormone (GH) from the hypophysis as well as regulate the GH concentrations in animals and humans. In this article, we describe the regulation of animal growth using plasmid DNA encoding both the GHRH gene and the SS gene fused with the hepatitis B surface antigen (HBsAg) gene. We constructed a series of expression plasmids to express the GHRH and HBsAg-SS fusion genes individually as well as collectively. The fusion gene and GHRH were successfully expressed in Chinese hamster ovary (CHO) cells, as proven by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoblotting tests. Poly D, L-lactide-co-glycolic acid (PLGA) plasmid-encapsulating microspheres were prepared and injected intramuscularly into the leg skeletal muscles of rabbits. Weight gain/day and the levels of insulinlike growth factor-I (IGF-I), SS, and hepatitis B surface antibody (HBsAb) were monitored. During days 30 postinjection, increase in weight gain/day and IGF- I concentration and decrease in SS were observed in treatment groups. From days 15 to 30 postinjection, the weight gain/day significantly increased (P gain/day (P gain/day in rabbits.

  9. Carcinoembryonic antigen (CEA)

    International Nuclear Information System (INIS)

    Ephraim, K.H.; Cox, P.H.; Hamer, C.J.A. v.d.; Berends, W.; Delhez, H.

    1977-01-01

    The carcinoembryonic antigen (CEA) is a complex of antigen determinants and also the carrier of these determinants. Chemically it is a glycoprotein. Its occurrence in blood serum or urine is correlated with malignant disease. Several radioimmunoassays (RIA) have been developed, one by Hoffmann-Laroche and one by the Rotterdam Radiotherapeutic Institute. Both methods and the Hoffmann assay kit are tested. Specifications are given for isolation of the antigen, preparation of the antiserum, and the execution of the RIA. Biochemical and clinical aspects are discussed

  10. Bacterial Ghosts as antigen and drug delivery system for ocular surface diseases: Effective internalization of Bacterial Ghosts by human conjunctival epithelial cells.

    Science.gov (United States)

    Kudela, Pavol; Koller, Verena Juliana; Mayr, Ulrike Beate; Nepp, Johannes; Lubitz, Werner; Barisani-Asenbauer, Talin

    2011-05-20

    The purpose of the presented investigation was to examine the efficiency of the novel carrier system Bacterial Ghosts (BGs), which are empty bacterial cell envelopes of Gram-negative bacteria to target human conjunctival epithelial cells, as well as to test the endocytic capacity of conjunctival cells after co-incubation with BGs generated from different bacterial species, and to foreclose potential cytotoxic effects caused by BGs. The efficiency of conjunctival cells to internalize BGs was investigated using the Chang conjunctival epithelial cell line and primary human conjunctiva-derived epithelial cells (HCDECs) as in vitro model. A high capacity of HCDECs to functionally internalize BGs was detected with the level of internalization depending on the type of species used for BGs generation. Detailed analysis showed no cytotoxic effect of BGs on HCDECs independently of the used bacterial species. Moreover, co-incubation with BGs did not enhance expression of both MHC class I and class II molecules by HCDECs, but increased expression of ICAM-1. The high rates of BG's internalization by HCDECs with no BG-mediated cytotoxic impact designate this carrier system to be a promising candidate for an ocular surface drug delivery system. BGs could be useful for future therapeutic ocular surface applications and eye-specific disease vaccine development including DNA transfer. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Targeted disruption of a ring-infected erythrocyte surface antigen (RESA)-like export protein gene in Plasmodium falciparum confers stable chondroitin 4-sulfate cytoadherence capacity

    DEFF Research Database (Denmark)

    Goel, Suchi; Muthusamy, Arivalagan; Miao, Jun

    2014-01-01

    . In this study, microarray transcriptome analysis showed that the absence of a gene cluster, comprising kahrp, pfemp3, and four other genes, results in the loss of parasitized erythrocytes adhering to chondroitin 4-sulfate (C4S). The role of one of these genes, PF3D7_0201600/PFB0080c, which encodes PHISTb...... (Plasmodium helical interspersed subtelomeric b) domain-containing RESA-like protein 1 expressed on the infected erythrocyte surface, was investigated. Disruption of PFB0080c resulted in increased var2csa transcription and VAR2CSA surface expression, leading to higher C4S-binding capacity of infected...... erythrocytes. Further, PFB0080c-knock-out parasites stably maintained the C4S adherence through many generations of growth. Although the majority of PFB0080c-knock-out parasites bound to C4S even after culturing for 6 months, a minor population bound to both C4S and CD36. These results strongly suggest...

  12. Genomic Methylation Inhibits Expression of Hepatitis B Virus Envelope Protein in Transgenic Mice: A Non-Infectious Mouse Model to Study Silencing of HBV Surface Antigen Genes.

    Science.gov (United States)

    Graumann, Franziska; Churin, Yuri; Tschuschner, Annette; Reifenberg, Kurt; Glebe, Dieter; Roderfeld, Martin; Roeb, Elke

    2015-01-01

    The Hepatitis B virus genome persists in the nucleus of virus infected hepatocytes where it serves as template for viral mRNA synthesis. Epigenetic modifications, including methylation of the CpG islands contribute to the regulation of viral gene expression. The present study investigates the effects of spontaneous age dependent loss of hepatitis B surface protein- (HBs) expression due to HBV-genome specific methylation as well as its proximate positive effects in HBs transgenic mice. Liver and serum of HBs transgenic mice aged 5-33 weeks were analyzed by Western blot, immunohistochemistry, serum analysis, PCR, and qRT-PCR. From the third month of age hepatic loss of HBs was observed in 20% of transgenic mice. The size of HBs-free area and the relative number of animals with these effects increased with age and struck about 55% of animals aged 33 weeks. Loss of HBs-expression was strongly correlated with amelioration of serum parameters ALT and AST. In addition lower HBs-expression went on with decreased ER-stress. The loss of surface protein expression started on transcriptional level and appeared to be regulated epigenetically by DNA methylation. The amount of the HBs-expression correlated negatively with methylation of HBV DNA in the mouse genome. Our data suggest that methylation of specific CpG sites controls gene expression even in HBs-transgenic mice with truncated HBV genome. More important, the loss of HBs expression and intracellular aggregation ameliorated cell stress and liver integrity. Thus, targeted modulation of HBs expression may offer new therapeutic approaches. Furthermore, HBs-transgenic mice depict a non-infectious mouse model to study one possible mechanism of HBs gene silencing by hypermethylation.

  13. Analysis of hepatitis B surface antigen (HBsAg) using high-sensitivity HBsAg assays in hepatitis B virus carriers in whom HBsAg seroclearance was confirmed by conventional assays.

    Science.gov (United States)

    Ozeki, Itaru; Nakajima, Tomoaki; Suii, Hirokazu; Tatsumi, Ryoji; Yamaguchi, Masakatsu; Kimura, Mutsuumi; Arakawa, Tomohiro; Kuwata, Yasuaki; Ohmura, Takumi; Hige, Shuhei; Karino, Yoshiyasu; Toyota, Joji

    2018-02-01

    We investigated the utility of high-sensitivity hepatitis B surface antigen (HBsAg) assays compared with conventional HBsAg assays. Using serum samples from 114 hepatitis B virus (HBV) carriers in whom HBsAg seroclearance was confirmed by conventional HBsAg assays (cut-off value, 0.05 IU/mL), the amount of HBsAg was re-examined by high-sensitivity HBsAg assays (cut-off value, 0.005 IU/mL). Cases negative for HBsAg in both assays were defined as consistent cases, and cases positive for HBsAg in the high-sensitivity HBsAg assay only were defined as discrepant cases. There were 55 (48.2%) discrepant cases, and the range of HBsAg titers determined by high-sensitivity HBsAg assays was 0.005-0.056 IU/mL. Multivariate analysis showed that the presence of nucleos(t)ide analog therapy, liver cirrhosis, and negative anti-HBs contributed to the discrepancies between the two assays. Cumulative anti-HBs positivity rates among discrepant cases were 12.7%, 17.2%, 38.8%, and 43.9% at baseline, 1 year, 3 years, and 5 years, respectively, whereas the corresponding rates among consistent cases were 50.8%, 56.0%, 61.7%, and 68.0%, respectively. Hepatitis B virus DNA negativity rates were 56.4% and 81.4% at baseline, 51.3% and 83.3% at 1 year, and 36.8% and 95.7% at 3 years, among discrepant and consistent cases, respectively. Hepatitis B surface antigen reversion was observed only in discrepant cases. Re-examination by high-sensitivity HBsAg assays revealed that HBsAg was positive in approximately 50% of cases. Cumulative anti-HBs seroconversion rates and HBV-DNA seroclearance rates were lower in these cases, suggesting a population at risk for HBsAg reversion. © 2017 The Japan Society of Hepatology.

  14. The prevalence of hepatitis B virus E antigen among Ghanaian ...

    African Journals Online (AJOL)

    We studied the prevalence of hepatitis B virus 'e' antigen (HBeAg) among individuals determined to be hepatitis B virus (HBV) surface antigen- positive and analyzed the gender/age category associated with more active HBV infection and whether alteration in the levels of alanine aminotransferase could be associated with ...

  15. Comparison of bovine lymphocyte antigen DRB3.2 allele ...

    African Journals Online (AJOL)

    The bovine lymphocyte antigen (BoLA-DRB3) gene encodes cell surface glycoproteins that initiate immune responses by presenting processed antigenic peptides to CD4 T helper cells. DRB3 is the most polymorphic bovine MHC class II gene which encodes the peptide-binding groove. Since different alleles favor the ...

  16. The Neck Region of the C-type Lectin DC-SIGN Regulates Its Surface Spatiotemporal Organization and Virus-binding Capacity on Antigen-presenting Cells*

    Science.gov (United States)

    Manzo, Carlo; Torreno-Pina, Juan A.; Joosten, Ben; Reinieren-Beeren, Inge; Gualda, Emilio J.; Loza-Alvarez, Pablo; Figdor, Carl G.; Garcia-Parajo, Maria F.; Cambi, Alessandra

    2012-01-01

    The C-type lectin DC-SIGN expressed on dendritic cells (DCs) facilitates capture and internalization of a plethora of different pathogens. Although it is known that DC-SIGN organizes in nanoclusters at the surface of DCs, the molecular mechanisms responsible for this well defined nanopatterning and role in viral binding remain enigmatic. By combining biochemical and advanced biophysical techniques, including optical superresolution and single particle tracking, we demonstrate that DC-SIGN intrinsic nanoclustering strictly depends on its molecular structure. DC-SIGN nanoclusters exhibited free, Brownian diffusion on the cell membrane. Truncation of the extracellular neck region, known to abrogate tetramerization, significantly reduced nanoclustering and concomitantly increased lateral diffusion. Importantly, DC-SIGN nanocluster dissolution exclusively compromised binding to nanoscale size pathogens. Monte Carlo simulations revealed that heterogeneity on nanocluster density and spatial distribution confers broader binding capabilities to DC-SIGN. As such, our results underscore a direct relationship between spatial nanopatterning, driven by intermolecular interactions between the neck regions, and receptor diffusion to provide DC-SIGN with the exquisite ability to dock pathogens at the virus length scale. Insight into how virus receptors are organized prior to virus binding and how they assemble into functional platforms for virus docking is helpful to develop novel strategies to prevent virus entry and infection. PMID:23019323

  17. Antigenic differences within the Cryptosporidium hominis and Cryptosporidium parvum surface proteins P23 and GP900 defined by monoclonal antibody reactivity.

    Science.gov (United States)

    Sturbaum, Gregory D; Schaefer, Deborah A; Jost, B Helen; Sterling, Charles R; Riggs, Michael W

    2008-06-01

    The biological basis for the specificity of host infectivity patterns of Cryptosporidium spp., in particular C. hominis and C. parvum, has yet to be fully elucidated. Comparison of the C. parvum and C. hominis P23 and GP900 predicted amino acid sequences revealed 3 differences in P23 and 4 and 17 differences in GP900 domains 1 and 5, respectively. Using monoclonal antibodies developed against the surface (glyco)proteins P23 and GP900 of the C. parvum Iowa isolate, solubilized glycoprotein from three C. hominis isolates was screened for reactivity using Western immunoblots. One of ten P23 MAbs and three of 21 GP900 MAbs were not reactive with any of the three C. hominis isolates. The non-reactive P23 MAb binds to a peptide epitope, while the non-reactive GP900 MAbs bind to either carbohydrate/carbohydrate-dependent or peptide epitopes of C. parvum. These results demonstrate phenotypic differences between C. hominis and C. parvum within two (glyco)proteins that are involved in parasite gliding motility and attachment/invasion.

  18. MEASUREMENT OF AFFINITY IN SERUM SAMPLES OF ANTIGEN-FREE, GERM-FREE AND CONVENTIONAL MICE AFTER HYPERIMMUNIZATION WITH 2,4-DINITROPHENYL KEYHOLE LIMPET HEMOCYANIN, USING SURFACE-PLASMON RESONANCE

    NARCIS (Netherlands)

    BAKKER, R; LASONDER, E; BOS, NA

    We previously investigated the primary and secondary responses and hyperimmunization to the T cell-dependent antigen 2,4-dinitrophenyl keyhole limpet hemocyanin (DNP-KLH) in antigen-free (AF), germ-free (GF) and conventional (CV) mice. Both the absolute and relative numbers of DNP-specific

  19. Cationic lipid-formulated DNA vaccine against hepatitis B virus: immunogenicity of MIDGE-Th1 vectors encoding small and large surface antigen in comparison to a licensed protein vaccine.

    Directory of Open Access Journals (Sweden)

    Anne Endmann

    Full Text Available Currently marketed vaccines against hepatitis B virus (HBV based on the small (S hepatitis B surface antigen (HBsAg fail to induce a protective immune response in about 10% of vaccinees. DNA vaccination and the inclusion of PreS1 and PreS2 domains of HBsAg have been reported to represent feasible strategies to improve the efficacy of HBV vaccines. Here, we evaluated the immunogenicity of SAINT-18-formulated MIDGE-Th1 vectors encoding the S or the large (L protein of HBsAg in mice and pigs. In both animal models, vectors encoding the secretion-competent S protein induced stronger humoral responses than vectors encoding the L protein, which was shown to be retained mainly intracellularly despite the presence of a heterologous secretion signal. In pigs, SAINT-18-formulated MIDGE-Th1 vectors encoding the S protein elicited an immune response of the same magnitude as the licensed protein vaccine Engerix-B, with S protein-specific antibody levels significantly higher than those considered protective in humans, and lasting for at least six months after the third immunization. Thus, our results provide not only the proof of concept for the SAINT-18-formulated MIDGE-Th1 vector approach but also confirm that with a cationic-lipid formulation, a DNA vaccine at a relatively low dose can elicit an immune response similar to a human dose of an aluminum hydroxide-adjuvanted protein vaccine in large animals.

  20. Improved humoral and cellular immune response against the gp120 V3 loop of HIV-1 following genetic immunization with a chimeric DNA vaccine encoding the V3 inserted into the hepatites B surface antigen

    DEFF Research Database (Denmark)

    Fomsgaard, A.; Nielsen, H.V.; Bryder, K.

    1998-01-01

    -2d-restricted cytotoxic T lymphocyte (CTL) epitope. In an attempt to improve the immunogenicity of V3 in DNA vaccines, a plasmid expressing MN V3 as a fusion protein with the highly immunogenic middle (pre-S2+S) surface antigen of hepatitis B virus (HBsAg) was constructed. Epidermal inoculation...... by gene gun was used for genetic immunization in a mouse model. Antibody and CTL responses to MN V3 and HBsAg were measured and compared with the immune responses obtained after vaccination with plasmids encoding the complete HIV-1 MN gp160 and HBsAg (pre-S2+S), respectively. DNA vaccination with the HIV...... MN gp160 envelope plasmid induced a slow and low titred anti-MN V3 antibody response at 12 weeks post-inoculation (p.i.) and a late appearing (7 weeks), weak and variable CTL response. In contrast, DNA vaccination with the HBsAg-encoding plasmid induced a rapid and high titred anti-HBsAg antibody...

  1. Antigen processing and remodeling of the endosomal pathway: requirements for antigen cross-presentation.

    Directory of Open Access Journals (Sweden)

    Ewoud Bernardus Compeer

    2012-03-01

    Full Text Available The cross-presentation of endocytosed antigen as peptide/class I MHC complexes plays a central role in the elicitation of CD8+ T cell clones that mediate anti-viral and anti-tumor immune responses. While it has been clear that there are specific subsets of professional antigen presenting cells (APC capable of antigen cross-presentation, description of mechanisms involved is still ongoing. Especially amongst dendritic cells (DC, there are specialized subsets that are highly proficient at antigen cross-presentation. We here present a focused survey on the cell biological processes in the endosomal pathway that support antigen cross-presentation. This review highlight DC-intrinsic mechanisms that facilitate the cross-presentation of endocytosed antigen, including receptor-mediated uptake, recycling and maturation including the sorting of membrane proteins, dynamic remodeling of endosomal structures and cell-surface directed endosomal trafficking. We will conclude with description of pathogen-induced deviation of endosomal processing, and discuss how immune evasion strategies pertaining endosomal trafficking may preclude antigen cross-presentation.

  2. Hepatitis B virus surface antigen (HBsAg)-positive and HBsAg-negative hepatitis B virus infection among mother-teenager pairs 13 years after neonatal hepatitis B virus vaccination.

    Science.gov (United States)

    Yao, Qing-Qing; Dong, Xiao-Lian; Wang, Xue-Cai; Ge, Sheng-Xiang; Hu, An-Qun; Liu, Hai-Yan; Wang, Yueping Alex; Yuan, Quan; Zheng, Ying-Jie

    2013-02-01

    It is unclear whether a mother who is negative for hepatitis B virus surface antigen (HBsAg) but positive for hepatitis B virus (HBV) is at potential risk for mother-to-child transmission of HBV. This study, using a paired mother-teenager population, aimed to assess whether maternal HBsAg-negative HBV infection ((hn)HBI) is a significant source of child HBV infection (HBI). A follow-up study with blood collection has been conducted on the 93 mother-teenager pairs from the initial 135 pregnant woman-newborn pairs 13 years after neonatal HBV vaccination. Serological and viral markers of HBV have been tested, and phylogenetic analysis of HBV isolates has been done. The HBI prevalence was 1.9% (1 (hn)HBI/53) for teenage children of non-HBI mothers, compared with 16.7% (1 (hn)HBI/6) for those of (hn)HBI mothers and 2.9% (1 HBsAg-positive HBV infection [(hp)HBI]/34) for those of (hp)HBI mothers. Similar viral sequences have been found in one pair of whom both the mother and teenager have had (hn)HBI. In comparison with the (hp)HBI cases, those with (hn)HBI had a lower level of HBV load and a higher proportion of genotype-C strains, which were accompanied by differentiated mutations (Q129R, K141E, and Y161N) of the "a" determinant of the HBV surface gene. Our findings suggest that mother-to-teenager transmission of (hn)HBI can occur among those in the neonatal HBV vaccination program.

  3. Results from tandem Phase 1 studies evaluating the safety, reactogenicity and immunogenicity of the vaccine candidate antigen Plasmodium falciparum FVO merozoite surface protein-1 (MSP142 administered intramuscularly with adjuvant system AS01

    Directory of Open Access Journals (Sweden)

    Otsyula Nekoye

    2013-01-01

    Full Text Available Abstract Background The development of an asexual blood stage vaccine against Plasmodium falciparum malaria based on the major merozoite surface protein-1 (MSP1 antigen is founded on the protective efficacy observed in preclinical studies and induction of invasion and growth inhibitory antibody responses. The 42 kDa C-terminus of MSP1 has been developed as the recombinant protein vaccine antigen, and the 3D7 allotype, formulated with the Adjuvant System AS02A, has been evaluated extensively in human clinical trials. In preclinical rabbit studies, the FVO allele of MSP142 has been shown to have improved immunogenicity over the 3D7 allele, in terms of antibody titres as well as growth inhibitory activity of antibodies against both the heterologous 3D7 and homologous FVO parasites. Methods Two Phase 1 clinical studies were conducted to examine the safety, reactogenicity and immunogenicity of the FVO allele of MSP142 in the adjuvant system AS01 administered intramuscularly at 0-, 1-, and 2-months: one in the USA and, after evaluation of safety data results, one in Western Kenya. The US study was an open-label, dose escalation study of 10 and 50 μg doses of MSP142 in 26 adults, while the Kenya study, evaluating 30 volunteers, was a double-blind, randomized study of only the 50 μg dose with a rabies vaccine comparator. Results In these studies it was demonstrated that this vaccine formulation has an acceptable safety profile and is immunogenic in malaria-naïve and malaria-experienced populations. High titres of anti-MSP1 antibodies were induced in both study populations, although there was a limited number of volunteers whose serum demonstrated significant inhibition of blood-stage parasites as measured by growth inhibition assay. In the US volunteers, the antibodies generated exhibited better cross-reactivity to heterologous MSP1 alleles than a MSP1-based vaccine (3D7 allele previously tested at both study sites. Conclusions Given that the primary

  4. Differential Growth of Francisella tularensis, Which Alters Expression of Virulence Factors, Dominant Antigens, and Surface-Carbohydrate Synthases, Governs the Apparent Virulence of Ft SchuS4 to Immunized Animals

    Directory of Open Access Journals (Sweden)

    Kristen M. Holland

    2017-06-01

    Full Text Available The gram-negative bacterium Francisella tularensis (Ft is both a potential biological weapon and a naturally occurring microbe that survives in arthropods, fresh water amoeba, and mammals with distinct phenotypes in various environments. Previously, we used a number of measurements to characterize Ft grown in Brain-Heart Infusion (BHI broth as (1 more similar to infection-derived bacteria, and (2 slightly more virulent in naïve animals, compared to Ft grown in Mueller Hinton Broth (MHB. In these studies we observed that the free amino acids in MHB repress expression of select Ft virulence factors by an unknown mechanism. Here, we tested the hypotheses that Ft grown in BHI (BHI-Ft accurately displays a full protein composition more similar to that reported for infection-derived Ft and that this similarity would make BHI-Ft more susceptible to pre-existing, vaccine-induced immunity than MHB-Ft. We performed comprehensive proteomic analysis of Ft grown in MHB, BHI, and BHI supplemented with casamino acids (BCA and compared our findings to published “omics” data derived from Ft grown in vivo. Based on the abundance of ~1,000 proteins, the fingerprint of BHI-Ft is one of nutrient-deprived bacteria that—through induction of a stringent-starvation-like response—have induced the FevR regulon for expression of the bacterium's virulence factors, immuno-dominant antigens, and surface-carbohydrate synthases. To test the notion that increased abundance of dominant antigens expressed by BHI-Ft would render these bacteria more susceptible to pre-existing, vaccine-induced immunity, we employed a battery of LVS-vaccination and S4-challenge protocols using MHB- and BHI-grown Ft S4. Contrary to our hypothesis, these experiments reveal that LVS-immunization provides a barrier to infection that is significantly more effective against an MHB-S4 challenge than a BHI-S4 challenge. The differences in apparent virulence to immunized mice are profoundly greater

  5. Enhanced detection sensitivity of prostate-specific antigen via PSA-conjugated gold nanoparticles based on localized surface plasmon resonance: GNP-coated anti-PSA/LSPR as a novel approach for the identification of prostate anomalies.

    Science.gov (United States)

    Jazayeri, M H; Amani, H; Pourfatollah, A A; Avan, A; Ferns, G A; Pazoki-Toroudi, H

    2016-10-01

    Prostate-specific antigen (PSA) is used to screen for prostate disease, although it has several limitations in its application as an organ-specific or cancer-specific marker. Furthermore, a highly specific/sensitive and/or label-free identification of PSA still remains a challenge in the diagnosis of prostate anomalies. We aimed to develop a gold nanoparticle (GNP)-conjugated anti-PSA antibody-based localized surface plasmon resonance (LSPR) as a novel approach to detect prostatic disease. A total of 25 nm colloidal gold particles were prepared followed by conjugation with anti-PSA pAb (GNPs-PSA pAb). LSPR was used to monitor the absorption changes of the aggregation of the particles. The size, shape and stability of the GNP-anti-PSA were evaluated by dynamic light scattering transmission electron microscopy (TEM) and zetasizer. The GNPs-conjugated PSA-pAb was successfully synthesized and subsequently characterized using ultraviolet absorption spectroscopy and TEM to determine the size distribution, crystallinity and stability of the particles (for example, stability of GNP: 443 mV). To increase the stability of the particles, we pegylated GNPs using an N-(3-dimethylaminopropyl)-N*-ethylcarbodiimide hydrochloride (EDC)/N-hydroxylsuccinimide (NHS) linker (for example, stability of GNP after pegylation: 272 mV). We found a significant increase in the absorbance and intensity of the particles with extinction peak at 545/2 nm, which was shifted by ~1 nm after conjugation. To illustrate the potential of the GNPs-PSA pAb to bind specifically to PSA, LSPR was used. We found that the extinction peak shifted 3 nm for a solution of 100 nM unlabeled antigen. In summary, we have established a novel approach for improving the efficacy/sensitivity of PSA in the assessment of prostate disease, supporting further investigation on the diagnostic value of GNP-conjugated anti-PSA/LSPR for the detection of prostate cancer.

  6. Effect of radiation on the expression of tumor-associated antigens of human lung adenocarcinoma cells

    International Nuclear Information System (INIS)

    Hareyama, Masato

    1988-01-01

    We studied the effects of irradiation on the expression of a tumor-associated antigen (YH206 antigen) of cultured human lung adenocarcinoma A549 cells by using enzyme-linked immunosorbent assay (ELISA) and flow cytometry. YH206 antigen is preferentially expressed on adenocarcinoma cells. Irradiation of A549 cells remarkably increased the expression of YH206 antigen on the cell surface and the level of the antigen in the culture supernatant as well as in the cell lysate, whereas it significantly affected the expression of HLA (MHC-class I) antigen on the same cells. The expression of HLA antigen on the cell was also increased after treatment of the cells with interferon-γ. In an additional experiment, cells were stained simultaneously for surface antigens (fluorescein coupled antibodies) and for DNA content (propidium iodide), and then dual parameter measurements were performed by flow cytometry to analyse the relationship between antigen levels and the cell cycle. YH206 antigen and HLA antigen increased more in the S and G 2 /M phases of the cell cycle than in G 0 /G 1 . The expression of YH206 antigen was enhanced in the S and G 2 /M phases by irradiation, whereas the expression of HLA antigen was enhanced in each phase of the cell cycle with irradiation or IFN. These results suggest that irradiation plays a key role in the change of the expression of certain tumor-associated antigens. (author)

  7. An immobilization antigen gene of the fish-parasitic protozoan Ichthyophthirius multifiliis strain ARS-6

    Science.gov (United States)

    Ichthyophthirius multifiliis (Ich) is a severe fish parasite that causes ‘white spot’ disease in many freshwater fish and leads to high mortality. The antigens on the parasite surface are involved in the antibody-mediated immobilization and hence designated as immobilization antigens (i-antigens). ...

  8. A monkey antigen crossreacting with carcinoembryonic antigen, CEA.

    Science.gov (United States)

    Engvall, E.; Vuento, M.; Ruoslahti, E.

    1976-01-01

    Normal monkey tissues were found to contain an antigen which crossreacts immunologically with the carcinoembryonic antigen (CEA) of the human digestive tract. The monkey antigen reacted with complete or partial identity to the normal crossreacting antigen (NCA) in humans when tested in immunodiffusion against anti-CEA or anti-NCA. Extracts of monkey tissues inhibited in radioimmunoassays measuring human NCA. It is possible that monkey foetuses and colonic tumours contain CEA. Images Fig. 1 PMID:823952

  9. Antigen smuggling in tuberculosis.

    Science.gov (United States)

    Hudrisier, Denis; Neyrolles, Olivier

    2014-06-11

    The importance of CD4 T lymphocytes in immunity to M. tuberculosis is well established; however, how dendritic cells activate T cells in vivo remains obscure. In this issue of Cell Host & Microbe, Srivastava and Ernst (2014) report a mechanism of antigen transfer for efficient activation of antimycobacterial T cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2001-01-01

    Roč. 58, č. 6 (2001), s. 425-430 ISSN 0001-2815. [Conference on Human leucocyte differentiation antigens /7./. Harrogate, 20.06.2000-25.06.2000] Institutional research plan: CEZ:AV0Z5052915 Keywords : CD molecules, HLDA Subject RIV: EC - Immunology Impact factor: 2.864, year: 2001

  11. CD antigens 2002

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2002-01-01

    Roč. 99, č. 10 (2002), s. 3877-3880 ISSN 0006-4971. [Conference on Human leucocyte differentiation antigens /7./. Harrogate, 20.06.2000-25.06.2000] Institutional research plan: CEZ:AV0Z5052915 Keywords : CD molecules, HLDA Subject RIV: EC - Immunology Impact factor: 9.631, year: 2002

  12. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2002-01-01

    Roč. 168, č. 5 (2002), s. 2083-2086 ISSN 0022-1767. [Conference on Human leucocyte differentiation antigens /7./. Harrogate, 20.06.2000-25.06.2000] Institutional research plan: CEZ:AV0Z5052915 Keywords : CD molecules, HLDA Subject RIV: EC - Immunology Impact factor: 7.014, year: 2002

  13. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2001-01-01

    Roč. 103, č. 4 (2001), s. 401-406 ISSN 0019-2805 R&D Projects: GA ČR GA310/99/0349 Institutional research plan: CEZ:AV0Z5052915 Keywords : antigen * CD * leukocyte Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.656, year: 2001

  14. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2001-01-01

    Roč. 19, č. 6 (2001), s. 556-562 ISSN 1066-5099 R&D Projects: GA AV ČR IAA7052904 Institutional research plan: CEZ:AV0Z5052915 Keywords : CD * leukocyte antigens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.689, year: 2001

  15. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2001-01-01

    Roč. 31, č. 10 (2001), s. 2841-2847 ISSN 0014-2980 R&D Projects: GA AV ČR IAA7052904 Keywords : CD * leukocyte antigens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.990, year: 2001

  16. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2001-01-01

    Roč. 211, č. 2 (2001), s. 81-85 ISSN 0008-8749 R&D Projects: GA ČR GA310/99/0349 Institutional research plan: CEZ:AV0Z5052915 Keywords : antigen * CD * leukocyte Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.604, year: 2001

  17. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2002-01-01

    Roč. 15, č. 1 (2002), s. 71-76 ISSN 0893-3952. [Conference on Human leucocyte differentiation antigens /7./. Harrogate, 20.06.2000-25.06.2000] Institutional research plan: CEZ:AV0Z5052915 Keywords : CD molecules, HLDA Subject RIV: EC - Immunology Impact factor: 3.821, year: 2002

  18. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2001-01-01

    Roč. 70, č. 5 (2001), s. 685-690 ISSN 0741-5400 R&D Projects: GA AV ČR IAA7052904 Institutional research plan: CEZ:AV0Z5052915 Keywords : CD * leukocyte antigens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.516, year: 2001

  19. CD antigens 2001

    Czech Academy of Sciences Publication Activity Database

    Mason, D.; Andre, P.; Bensussan, A.; Buckley, C.; Civin, C.; Clark, E.; de Haas, M.; Goyert, S.; Hadam, M.; Hart, D.; Hořejší, Václav; Meuer, S.; Morrissey, J.; Schwartz-Albiez, R.; Shaw, S.; Simmons, D.; Uguccioni, M.; van der Schoot, E.; Vivier, E.; Zola, H.

    2001-01-01

    Roč. 13, č. 9 (2001), s. 1095-1098 ISSN 0953-8178 R&D Projects: GA ČR GA310/99/0349 Institutional research plan: CEZ:AV0Z5052915 Keywords : antigen * CD * leukocyte Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.611, year: 2001

  20. β-endorphin antigen

    International Nuclear Information System (INIS)

    1981-01-01

    This invention relates to the production of antigens comprising β-endorphin, βsub(h)-endorphin, or βsub(c)-endorphin, in covalent conjugation with human gammaglobulin as immunogenic carrier material, and an antibody having the property of specifically binding β-endorphin or fragments thereof, containing the (6-15) residue sequence. (U.K.)

  1. Reduced prevalence of hepatitis B surface antigen positivity among pregnant women born after the national implementation of immunoprophylaxis for babies born to hepatitis B virus-carrier mothers in Japan.

    Science.gov (United States)

    Sugiyama, Aya; Ohisa, Masayuki; Nagashima, Shintaro; Yamamoto, Chikako; Chuon, Channarena; Fujii, Toshiko; Akita, Tomoyuki; Katayama, Keiko; Kudo, Yoshiki; Tanaka, Junko

    2017-11-01

    We aimed to estimate hepatitis B surface antigen (HBsAg) positivity among birth year-stratified pregnant women in Hiroshima, Japan, and compare prevalence rates between women born before and after implementation of a national immunoprophylactic vaccination program for babies born to hepatitis B virus (HBV) carrier mothers in Japan. Pregnant women who gave birth at all delivery hospitals/clinics in Hiroshima prefecture between 1 April 2010 and 31 March 2011 were eligible. Lists collected from each institution included survey items such as age (pregnant woman's birth year) and HBsAg and hepatitis C virus (HCV) antibody (anti-HCV) test results, which were posted anonymously and non-consolidated from medical records. We calculated the HBsAg and anti-HCV prevalence in our cohort according to the mothers' birth year. In 41 of 58 hospitals/clinics, 15 233 and 15 035 pregnant women underwent HBsAg and anti-HCV testing, corresponding to 59.6% and 58.9% of 25 546 births in the 2010 fiscal year, respectively. The overall HBsAg positive rate was 0.51% (95% confidence interval [CI], 0.40-0.63%), and an extremely low prevalence (0.10%; 95% CI, 0.00-0.25%) was observed among pregnant women born after 1986. However, the prevalence in this study was slightly higher than the nationwide value (0.31%) and the Chugoku region-specific value (0.46%) among first-time blood donors at Japanese Red Cross blood centers between 2001 and 2006. No significant difference in anti-HCV positivity was observed. Only two pregnant women born after the preventive program implementation were HBsAg-positive. Perinatal HBV transmission is estimated to be almost completely inhibited in the next generation. © 2017 The Authors. Hepatology Research published by John Wiley & Sons Australia, Ltd on behalf of Japan Society of Hepatology.

  2. Antigen Loss Variants: Catching Hold of Escaping Foes.

    Science.gov (United States)

    Vyas, Maulik; Müller, Rolf; Pogge von Strandmann, Elke

    2017-01-01

    Since mid-1990s, the field of cancer immunotherapy has seen steady growth and selected immunotherapies are now a routine and preferred therapeutic option of certain malignancies. Both active and passive cancer immunotherapies exploit the fact that tumor cells express specific antigens on the cell surface, thereby mounting an immune response specifically against malignant cells. It is well established that cancer cells typically lose surface antigens following natural or therapy-induced selective pressure and these antigen-loss variants are often the population that causes therapy-resistant relapse. CD19 and CD20 antigen loss in acute lymphocytic leukemia and chronic lymphocytic leukemia, respectively, and lineage switching in leukemia associated with mixed lineage leukemia (MLL) gene rearrangements are well-documented evidences in this regard. Although increasing number of novel immunotherapies are being developed, majority of these do not address the control of antigen loss variants. Here, we review the occurrence of antigen loss variants in leukemia and discuss the therapeutic strategies to tackle the same. We also present an approach of dual-targeting immunoligand effectively retargeting NK cells against antigen loss variants in MLL-associated leukemia. Novel immunotherapies simultaneously targeting more than one tumor antigen certainly hold promise to completely eradicate tumor and prevent therapy-resistant relapses.

  3. Boosting antibody responses by targeting antigens to dendritic cells.

    Science.gov (United States)

    Caminschi, Irina; Shortman, Ken

    2012-02-01

    Delivering antigens directly to dendritic cells (DCs) in situ, by injecting antigens coupled to antibodies specific for DC surface molecules, is a promising strategy for enhancing vaccine efficacy. Enhanced cytotoxic T cell responses are obtained if an adjuvant is co-administered to activate the DC. Such DC targeting is also effective at enhancing humoral immunity, via the generation of T follicular helper cells. Depending on the DC surface molecule targeted, antibody production can be enhanced even in the absence of adjuvants. In the case of Clec9A as the DC surface target, enhanced antibody production is a consequence of the DC-restricted expression of the target molecule. Few other cells absorb the antigen-antibody construct, therefore, it persists in the bloodstream, allowing sustained antigen presentation, even by non-activated DCs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Antigen binding characteristics of immunoglobulin free light chains: crosslinking by antigen is essential to induce allergic inflammation.

    Directory of Open Access Journals (Sweden)

    Marco Thio

    Full Text Available Beside the production of complete immunoglobulins IgG, IgE, IgA, IgM and IgD, consisting of tetrameric heterodimers of immunoglobulin heavy and light chains, B cells also secrete immunoglobulin free light chains (Ig-fLC. Previous studies showed that Ig-fLCs are able to induce immediate hypersensitivity reactions. It is apparent that recognition and binding of antigen are crucial steps in the onset of these inflammatory responses. In this study, the binding characteristics of Ig-fLC to antigen were further investigated using various biochemical approaches. In addition, we investigated whether antigen-mediated crosslinking of Ig-fLC is required to initiate allergic skin inflammation in vivo. Our study shows that binding of Ig-fLCs to antigen can be measured with different experimental setups. Surface plasmon resonance analysis showed real-time antigen binding characteristics. Specific antigen binding by Ig-fLCs was further detected using immunoblotting and ELISA. Using the ELISA-based assay, a binding affinity of 76.9±3.8 nM was determined for TNP-specific Ig-fLC. Antigen-induced ear swelling in mice passively sensitized with trinitrophenol-specific Ig-fLC was inhibited when multivalent antigen was combined with excess of monovalent antigen during challenge. We conclude that Ig-fLCs are able to interact with antigen, a prerequisite for antigen-specific cellular activation. In analogy to antigen-specific Fc receptor-induced mast cell activation, crosslinking of Ig-fLCs is necessary to initiate a local allergic response.

  5. Protein A-containing staphylococcus aureus as an immunoglobulin-binding reagent: 1) in radioimmunoassays - 'staf-RIA' - recently also for antibiotics and microbial antigens/antibodies, and 2) in a non-radioactive surface immunoassay - 'Staph-ace ay' read by the naked eye - primarily for antibodies to antigens adsorbed to transparent surfaces

    International Nuclear Information System (INIS)

    Jonsson, S.

    1977-01-01

    This paper is intended to summarize recent developments for the use of protein A-containing staphylococci as an immunoglobulin-binding reagent in various types of radioimmunoassay and some related areas, particularly the staphylococcal surface immunoassay. The paper also presents a new process for the large scale preparation of a freeze-dried preparation of the immunoglobulin-binding, killed staphylococci, which thereby gain a much improved suspension stability. (orig.) [de

  6. Mosaic VSGs and the scale of Trypanosoma brucei antigenic variation.

    Directory of Open Access Journals (Sweden)

    James P J Hall

    Full Text Available A main determinant of prolonged Trypanosoma brucei infection and transmission and success of the parasite is the interplay between host acquired immunity and antigenic variation of the parasite variant surface glycoprotein (VSG coat. About 0.1% of trypanosome divisions produce a switch to a different VSG through differential expression of an archive of hundreds of silent VSG genes and pseudogenes, but the patterns and extent of the trypanosome diversity phenotype, particularly in chronic infection, are unclear. We applied longitudinal VSG cDNA sequencing to estimate variant richness and test whether pseudogenes contribute to antigenic variation. We show that individual growth peaks can contain at least 15 distinct variants, are estimated computationally to comprise many more, and that antigenically distinct 'mosaic' VSGs arise from segmental gene conversion between donor VSG genes or pseudogenes. The potential for trypanosome antigenic variation is probably much greater than VSG archive size; mosaic VSGs are core to antigenic variation and chronic infection.

  7. Human platelet antigens - 2013.

    Science.gov (United States)

    Curtis, B R; McFarland, J G

    2014-02-01

    To date, 33 human platelet alloantigens (HPAs) have been identified on six functionally important platelet glycoprotein (GP) complexes and have been implicated in alloimmune platelet disorders including foetal and neonatal alloimmune thrombocytopenia (FNAIT), posttransfusion purpura (PTP) and multitransfusion platelet refractoriness (MPR). The greatest number of recognized HPA (20 of 33) resides on the GPIIb/IIIa complex, which serves as the receptor for ligands important in mediating haemostasis and inflammation. These include HPA-1a, the most commonly implicated HPA in FNAIT and PTP in Caucasian populations. Other platelet GP complexes, GPIb/V/IX, GPIa/IIa and CD109, express the remaining 13 HPAs. Of the recognized HPAs, 12 occur as six serologically and genetically defined biallelic 'systems' where the -a form designates the higher frequency allele and the -b form, the lower. Twenty-one other HPAs are low-frequency or rare antigens for which postulated higher frequency -a alleles have not yet been identified as antibody specificities. In addition to the HPA markers, platelets also express ABO and human leucocyte antigen (HLA) antigens; antibodies directed at the former are occasionally important in FNAIT, and to the latter, in MPR. © 2013 International Society of Blood Transfusion.

  8. Identification and characterization of new Leishmania promastigote surface antigens, LaPSA-38S and LiPSA-50S, as major immunodominant excreted/secreted components of L. amazonensis and L. infantum

    OpenAIRE

    Bras Goncalves, Rachel; Petitdidier, Elodie; Pagniez, Julie; Veyrier, Renaud; Cibrelus, P.; Cavaleyra, Mireille; Maquaire, S.; Moreaux, J.; Lemesre, Jean-Loup

    2014-01-01

    We have previously demonstrated that sera from dogs vaccinated with excreted/secreted antigens (ESA) of Leishmania infantum promastigotes (LiESAp) mainly recognized an immunodominant antigen of 54 kDa. An anti-LiESAp-specific IgG2 humoral response was observed and associated to Th1-type response in vaccinated dogs. This response was highly correlated with a long-lasting and strong LiES-Ap-vaccine protection toward L. infantum experimental infection. In addition, it was also shown that dogs fr...

  9. Oral vaccination of animals with antigens encapsulated in alginate microspheres.

    Science.gov (United States)

    Bowersock, T L; HogenEsch, H; Suckow, M; Guimond, P; Martin, S; Borie, D; Torregrosa, S; Park, H; Park, K

    1999-03-26

    Most infectious diseases begin at a mucosal surface. Prevention of infection must therefore consider ways to enhance local immunity to prevent the attachment and invasion of microbes. Despite this understanding, most vaccines depend on parenterally administered vaccines that induce a circulating immune response that often does not cross to mucosal sites. Administration of vaccines to mucosal sites induces local immunity. To be effective requires that antigen be administered often. This is not always practical depending on the site where protection is needed, nor comfortable to the patient. Not all mucosal sites have inductive lymphoid tissue present as well. Oral administration is easy to do, is well accepted by humans and animals and targets the largest inductive lymphoid tissue in the body in the intestine. Oral administration of antigen requires protection of antigen from the enzymes and pH of the stomach. Polymeric delivery systems are under investigation to deliver vaccines to the intestine while protecting them from adverse conditions that could adversely affect the antigens. They also can enhance delivery of antigen specifically to the inductive lymphoid tissue. Sodium alginate is a readily available, inexpensive polymer that can be used to encapsulate a wide variety of antigens under mild conditions. Orally administered alginate microspheres containing antigen have successfully induced immunity in mice to enteric (rotavirus) pathogens and in the respiratory tract in cattle with a model antigen (ovalbumin). This delivery system offers a safe, effective means of orally vaccinating large numbers of animals (and perhaps humans) to a variety of infectious agents.

  10. Prevalence of Serologic Hepatitis B Markers in Blood Donors From Puebla, Mexico: The Association of Relatively High Levels of Anti-Core Antibodies With the Detection of Surface Antigen and Genomic DNA.

    Science.gov (United States)

    Sosa-Jurado, Francisca; Hilda Rosas-Murrieta, Nora; Guzman-Flores, Belinda; Perez Zempoaltecalt, Cintia; Patricia Sanchez Torres, Ana; Ramirez Rosete, Leticia; Bernal-Soto, Maribel; Marquez-Dominguez, Luis; Melendez-Mena, Daniel; Angel Mendoza Torres, Miguel; Teresa Lopez Delgado, Maria; Reyes-Leyva, Julio; Vallejo-Ruiz, Veronica; Santos-Lopez, Gerardo

    2016-06-01

    The hepatitis B virus (HBV) causes chronic hepatitis, hepatic cirrhosis, and hepatocellular carcinoma. Surface antigen (HBsAg) detection is a definitive test that can confirm HBV infection, while the presence of antibodies against the core protein (anti-HBc) suggests either a previous or ongoing infection or occult hepatitis B infection (OBI). The aim of the present study was to determine the prevalence of anti-HBc and HBsAg in blood donors. Further, the study aimed to estimate the anti-HBc level at which HBV DNA is detected in putative OBI cases, as well as to search for mutations in the "a" determinant associated with the non-detection of HBsAg in serum. We conducted a cross-sectional study from 2003-2009. The study included 120,552 blood donors from the state of Puebla, Mexico. Different commercial systems based on microparticles (enzymatic (MEIA) or chemiluminescent (CMIA)) were used to determine the HBsAg and anti-HBc levels. For the detection of HBV DNA, a nested polymerase chain reaction (nested PCR) was used and the genotypes were determined using Sanger sequencing. Of the 120,552 blood donors, 1437 (1.19%, 95% CI: 1.12 - 1.26) were reactive to anti-HBc, while 82 (0.066%, 95% CI: 0.053 - 0.079) were reactive to HBsAg. Some 156 plasma samples collected in 2009 from anti-HBc-positive/HBsAg-negative blood donors were submitted for HBV DNA detection in a search for probable OBI. Viral DNA was detected in 27/156 (17.3%, 95% CI: 11.5 - 23.1). Our results show an association between HBV DNA or HBsAg and anti-HBc S/CO levels ≥ 4.0. All DNA samples were identified as genotype H and some "a" determinant mutations were identified, although none corresponded to mutations previously reported to hinder the detection of HBsAg by commercial immunoassays. We observed that as the anti-HBc levels increase, there is a higher prevalence of the viral protein HBsAg in blood donors. Samples testing positive for HBV-DNA were seen to exhibit a ten-fold higher presence of anti

  11. Prevalence of Serologic Hepatitis B Markers in Blood Donors From Puebla, Mexico: The Association of Relatively High Levels of Anti-Core Antibodies With the Detection of Surface Antigen and Genomic DNA

    Science.gov (United States)

    Sosa-Jurado, Francisca; Hilda Rosas-Murrieta, Nora; Guzman-Flores, Belinda; Perez Zempoaltecalt, Cintia; Patricia Sanchez Torres, Ana; Ramirez Rosete, Leticia; Bernal-Soto, Maribel; Marquez-Dominguez, Luis; Melendez-Mena, Daniel; Angel Mendoza Torres, Miguel; Teresa Lopez Delgado, Maria; Reyes-Leyva, Julio; Vallejo-Ruiz, Veronica; Santos-Lopez, Gerardo

    2016-01-01

    Background The hepatitis B virus (HBV) causes chronic hepatitis, hepatic cirrhosis, and hepatocellular carcinoma. Surface antigen (HBsAg) detection is a definitive test that can confirm HBV infection, while the presence of antibodies against the core protein (anti-HBc) suggests either a previous or ongoing infection or occult hepatitis B infection (OBI). Objectives The aim of the present study was to determine the prevalence of anti-HBc and HBsAg in blood donors. Further, the study aimed to estimate the anti-HBc level at which HBV DNA is detected in putative OBI cases, as well as to search for mutations in the “a” determinant associated with the non-detection of HBsAg in serum. Patients and Methods We conducted a cross-sectional study from 2003–2009. The study included 120,552 blood donors from the state of Puebla, Mexico. Different commercial systems based on microparticles (enzymatic (MEIA) or chemiluminescent (CMIA)) were used to determine the HBsAg and anti-HBc levels. For the detection of HBV DNA, a nested polymerase chain reaction (nested PCR) was used and the genotypes were determined using Sanger sequencing. Results Of the 120,552 blood donors, 1437 (1.19%, 95% CI: 1.12 - 1.26) were reactive to anti-HBc, while 82 (0.066%, 95% CI: 0.053 - 0.079) were reactive to HBsAg. Some 156 plasma samples collected in 2009 from anti-HBc-positive/HBsAg-negative blood donors were submitted for HBV DNA detection in a search for probable OBI. Viral DNA was detected in 27/156 (17.3%, 95% CI: 11.5 - 23.1). Our results show an association between HBV DNA or HBsAg and anti-HBc S/CO levels ≥ 4.0. All DNA samples were identified as genotype H and some “a” determinant mutations were identified, although none corresponded to mutations previously reported to hinder the detection of HBsAg by commercial immunoassays. Conclusions We observed that as the anti-HBc levels increase, there is a higher prevalence of the viral protein HBsAg in blood donors. Samples testing positive

  12. Filamentous bacteriophage fd as an antigen delivery system in vaccination.

    Science.gov (United States)

    Prisco, Antonella; De Berardinis, Piergiuseppe

    2012-01-01

    Peptides displayed on the surface of filamentous bacteriophage fd are able to induce humoral as well as cell-mediated immune responses, which makes phage particles an attractive antigen delivery system to design new vaccines. The immune response induced by phage-displayed peptides can be enhanced by targeting phage particles to the professional antigen presenting cells, utilizing a single-chain antibody fragment that binds dendritic cell receptor DEC-205. Here, we review recent advances in the use of filamentous phage fd as a platform for peptide vaccines, with a special focus on the use of phage fd as an antigen delivery platform for peptide vaccines in Alzheimer's Disease and cancer.

  13. Improved diagnostic performance of a commercial anaplasma antibody competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5–glutathione S-transferase fusion protein as antigen

    Science.gov (United States)

    This study tested the hypothesis that removal of maltose binding protein from recombinant antigen used for plate coating would improve the specificity of Anaplasma antibody competitive ELISA. Three hundred and eight sera with significant MBP antibody binding (=30%I) in Anaplasma negative herds was 1...

  14. Association of Pneumococcal Protein Antigen Serology With Age and Antigenic Profile of Colonizing Isolates.

    Science.gov (United States)

    Azarian, Taj; Grant, Lindsay R; Georgieva, Maria; Hammitt, Laura L; Reid, Raymond; Bentley, Stephen D; Goldblatt, David; Santosham, Mathuran; Weatherholtz, Robert; Burbidge, Paula; Goklish, Novalene; Thompson, Claudette M; Hanage, William P; O'Brien, Kate L; Lipsitch, Marc

    2017-03-01

    Several Streptococcus pneumoniae proteins play a role in pathogenesis and are being investigated as vaccine targets. It is largely unknown whether naturally acquired antibodies reduce the risk of colonization with strains expressing a particular antigenic variant. Serum immunoglobulin G (IgG) titers to 28 pneumococcal protein antigens were measured among 242 individuals aged - 30 days after serum collection, and the antigen variant in each pneumococcal isolate was determined using genomic data. We assessed the association between preexisting variant-specific antibody titers and subsequent carriage of pneumococcus expressing a particular antigen variant. Antibody titers often increased across pediatric groups before decreasing among adults. Individuals with low titers against group 3 pneumococcal surface protein C (PspC) variants were more likely to be colonized with pneumococci expressing those variants. For other antigens, variant-specific IgG titers do not predict colonization. We observed an inverse association between variant-specific antibody concentration and homologous pneumococcal colonization for only 1 protein. Further assessment of antibody repertoires may elucidate the nature of antipneumococcal antibody-mediated mucosal immunity while informing vaccine development. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  15. Cancer testis antigen and immunotherapy

    Directory of Open Access Journals (Sweden)

    Krishnadas DK

    2013-04-01

    Full Text Available Deepa Kolaseri Krishnadas, Fanqi Bai, Kenneth G Lucas Department of Pediatrics, Division of Hematology/Oncology, University of Louisville, KY, USA Abstract: The identification of cancer testis (CT antigens has been an important advance in determining potential targets for cancer immunotherapy. Multiple previous studies have shown that CT antigen vaccines, using both peptides and dendritic cell vaccines, can elicit clinical and immunologic responses in several different tumors. This review details the expression of melanoma antigen family A, 1 (MAGE-A1, melanoma antigen family A, 3 (MAGE-A3, and New York esophageal squamous cell carcinoma-1 (NY-ESO-1 in various malignancies, and presents our current understanding of CT antigen based immunotherapy. Keywords: cancer testis antigens, immunotherapy, vaccine

  16. Oligopeptide antigens of the angiotensin lineage compete for presentation by paraformaldehyde-treated accessory cells to T cells

    DEFF Research Database (Denmark)

    Buus, S; Werdelin, O

    1986-01-01

    The heptapeptide antigen angiotensin III can be presented to guinea pig T cells by paraformaldehyde-treated antigen-presenting cells, which are incapable of processing antigens and presumably cannot even ingest them. We demonstrate here that the decapeptide angiotensin I can outcompete angiotensin...... III for presentation by paraformaldehyde-treated antigen-presenting cells. It seems likely that the competition is for a site on the surface of the presenting cell. This extends earlier findings of competition for presentation between antigens. We also demonstrate that the antigens of the angiotensin...

  17. Molecular characteristics of an immobilization antigen gene of the fish-parasitic protozoan Ichthyophthirius multifiliis strain ARS-6

    Science.gov (United States)

    Ichthyophthirius multifiliis, a ciliated protozoan parasite of fish, expresses surface antigens (i-antigens), which react with host antibodies that render them immobile. The nucleotide sequence of an i-antigen gene of Ichthyophthirius multifiliis strain ARS-6 was deduced. The predicted protein of 47...

  18. Therapeutic Antibodies against Intracellular Tumor Antigens

    Directory of Open Access Journals (Sweden)

    Iva Trenevska

    2017-08-01

    Full Text Available Monoclonal antibodies are among the most clinically effective drugs used to treat cancer. However, their target repertoire is limited as there are relatively few tumor-specific or tumor-associated cell surface or soluble antigens. Intracellular molecules represent nearly half of the human proteome and provide an untapped reservoir of potential therapeutic targets. Antibodies have been developed to target externalized antigens, have also been engineered to enter into cells or may be expressed intracellularly with the aim of binding intracellular antigens. Furthermore, intracellular proteins can be degraded by the proteasome into short, commonly 8–10 amino acid long, peptides that are presented on the cell surface in the context of major histocompatibility complex class I (MHC-I molecules. These tumor-associated peptide–MHC-I complexes can then be targeted by antibodies known as T-cell receptor mimic (TCRm or T-cell receptor (TCR-like antibodies, which recognize epitopes comprising both the peptide and the MHC-I molecule, similar to the recognition of such complexes by the TCR on T cells. Advances in the production of TCRm antibodies have enabled the generation of multiple TCRm antibodies, which have been tested in vitro and in vivo, expanding our understanding of their mechanisms of action and the importance of target epitope selection and expression. This review will summarize multiple approaches to targeting intracellular antigens with therapeutic antibodies, in particular describing the production and characterization of TCRm antibodies, the factors influencing their target identification, their advantages and disadvantages in the context of TCR therapies, and the potential to advance TCRm-based therapies into the clinic.

  19. Antigen antibody interactions

    CERN Document Server

    DeLisi, Charles

    1976-01-01

    1. 1 Organization of the Immune System One of the most important survival mechanisms of vertebrates is their ability to recognize and respond to the onslaught of pathogenic microbes to which they are conti- ously exposed. The collection of host cells and molecules involved in this recognition­ 12 response function constitutes its immune system. In man, it comprises about 10 cells 20 (lymphocytes) and 10 molecules (immunoglobulins). Its ontogenic development is c- strained by the requirement that it be capable of responding to an almost limitless variety of molecular configurations on foreign substances, while simultaneously remaining inert to those on self components. It has thus evolved to discriminate, with exquisite precision, between molecular patterns. The foreign substances which induce a response, called antigens, are typically large molecules such as proteins and polysaccharides. The portions of these with which immunoglobulins interact are called epitopes or determinants. A typical protein epitope m...

  20. Cancer antigen 125 and prognosis

    DEFF Research Database (Denmark)

    Høgdall, Estrid Vilma Solyom

    2008-01-01

    cancer antigen 125 determination may be implemented into clinical practice, cut-off levels must be evaluated and internationally defined. Studies examining serum cancer antigen 125 levels after surgery but before, during, or after treatment confirmed that changes in serum levels are of prognostic value...

  1. Co-Administration of Lipid Nanoparticles and Sub-Unit Vaccine Antigens Is Required for Increase in Antigen-Specific Immune Responses in Mice

    Directory of Open Access Journals (Sweden)

    Elizabeth A. Thoryk

    2016-12-01

    Full Text Available A vast body of evidence suggests that nanoparticles function as potent immune-modulatory agents. We have previously shown that Merck proprietary Lipid NanoParticles (LNPs markedly boost B-cell and T-cell responses to sub-unit vaccine antigens in mice. To further evaluate the specifics of vaccine delivery and dosing regimens in vivo, we performed immunogenicity studies in BALB/c and C57BL/6 mice using two model antigens, Hepatitis B Surface Antigen (HBsAg and Ovalbumin (OVA, respectively. To assess the requirement for co-administration of antigen and LNP for the elicitation of immune responses, we evaluated immune responses after administering antigen and LNP to separate limbs, or administering antigen and LNP to the same limb but separated by 24 h. We also evaluated formulations combining antigen, LNP, and aluminum-based adjuvant amorphous aluminum hydroxylphosphate sulfate (MAA to look for synergistic adjuvant effects. Analyses of antigen-specific B-cell and T-cell responses from immunized mice revealed that the LNPs and antigens must be co-administered—both at the same time and in the same location—in order to boost antigen-specific immune responses. Mixing of antigen with MAA prior to formulation with LNP did not impact the generation of antigen-specific B-cell responses, but drastically reduced the ability of LNPs to boost antigen-specific T-cell responses. Overall, our data demonstrate that the administration of LNPs and vaccine antigen together enables their immune-stimulatory properties.

  2. A radioimmunoassay for human antibody specific for microbial antigens

    International Nuclear Information System (INIS)

    Tew, J.G.; Burmeister, J.; Greene, E.J.; Pflaumer, S.K.; Goldstein, J.

    1977-01-01

    A simple and sensitive method for detecting and quantitating antibody specific or microbial antigens is described. Bacterial, fungal, parasitic or viral antigens attached to bromoacetyl cellulose or the intact cells themselves were added to a series of two-fold dilutions of human serum. After a short incubation period, which allowed human antibody to attach to the antigens, the complex was thoroughly washed and carbon-14 labeled anti-human light chain antibody was added to each dilution. The resulting complex was washed, collected on a filter pad, placed in a scintillation vial and radioassayed. The relationship between radioactivity bound and -log 2 of the serum dilution was linear. The endpoint for each assay and a confidence interval was calculated by doing inverse prediction from simple linear regression. Results obtained using this assay indicated the presence of antibody in a pool of normal human sera specific for herpes virus and for both cell surface and intracellular antigens of Streptococcus mutans, Naegleria fowleri and Cryptococcus neoformans. In general the dominant response was against the intracellular antigens rather than cell surface antigens

  3. Posttransplant chimeric antigen receptor therapy.

    Science.gov (United States)

    Smith, Melody; Zakrzewski, Johannes; James, Scott; Sadelain, Michel

    2018-03-08

    Therapeutic T-cell engineering is emerging as a powerful approach to treat refractory hematological malignancies. Its most successful embodiment to date is based on the use of second-generation chimeric antigen receptors (CARs) targeting CD19, a cell surface molecule found in most B-cell leukemias and lymphomas. Remarkable complete remissions have been obtained with autologous T cells expressing CD19 CARs in patients with relapsed, chemo-refractory B-cell acute lymphoblastic leukemia, chronic lymphocytic leukemia, and non-Hodgkin lymphoma. Allogeneic CAR T cells may also be harnessed to treat relapse after allogeneic hematopoietic stem cell transplantation. However, the use of donor T cells poses unique challenges owing to potential alloreactivity. We review different approaches to mitigate the risk of causing or aggravating graft-versus-host disease (GVHD), including CAR therapies based on donor leukocyte infusion, virus-specific T cells, T-cell receptor-deficient T cells, lymphoid progenitor cells, and regulatory T cells. Advances in CAR design, T-cell selection and gene editing are poised to enable the safe use of allogeneic CAR T cells without incurring GVHD. © 2018 by The American Society of Hematology.

  4. Lym-1 Chimeric Antigen Receptor T Cells Exhibit Potent Anti-Tumor Effects against B-Cell Lymphoma

    OpenAIRE

    Long Zheng; Peisheng Hu; Brandon Wolfe; Caryn Gonsalves; Luqing Ren; Leslie A. Khawli; Harvey R. Kaslow; Alan L. Epstein

    2017-01-01

    T cells expressing chimeric antigen receptors (CARs) recognizing CD19 epitopes have produced remarkable anti-tumor effects in patients with B-cell malignancies. However, cancer cells lacking recognized epitopes can emerge, leading to relapse and death. Thus, CAR T cells targeting different epitopes on different antigens could improve immunotherapy. The Lym-1 antibody targets a conformational epitope of Human Leukocyte Antigen-antigen D Related (HLA-DR) on the surface of human B-cell lymphomas...

  5. A Phosphorylcholine-Containing Glycolipid-like Antigen Present on the Surface of Infective Stage Larvae of Ascaris spp. Is a Major Antibody Target in Infected Pigs and Humans

    Science.gov (United States)

    Masure, Dries; Wang, Tao; Nejsum, Peter; Hokke, Cornelis H.; Geldhof, Peter

    2016-01-01

    Background The pig parasite Ascaris suum plays and important role in veterinary medicine and represents a suitable model for A. lumbricoides, which infects over 800 million people. In pigs, continued exposure to Ascaris induces immunity at the level of the gut, protecting the host against migrating larvae. The objective of this study was to identify and characterize parasite antigens targeted by this local immune response that may be crucial for parasite invasion and establishment and to evaluate their protective and diagnostic potential. Methodology/Principal Findings Pigs were immunized by trickle infection for 30 weeks, challenged with 2,000 eggs at week 32 and euthanized two weeks after challenge. At necropsy, there was a 100% reduction in worms recovered from the intestine and a 97.2% reduction in liver white spots in comparison with challenged non-immune control animals. Antibodies purified from the intestinal mucus or from the supernatant of cultured antibody secreting cells from mesenteric lymph nodes of immune pigs were used to probe L3 extracts to identify antibody targets. This resulted in the recognition of a 12kDa antigen (As12) that is actively shed from infective Ascaris L3. As12 was characterized as a phosphorylcholine-containing glycolipid-like antigen that is highly resistant to different enzymatic and chemical treatments. Vaccinating pigs with an As12 fraction did not induce protective immunity to challenge infection. However, serological analysis using sera or plasma from experimentally infected pigs or naturally infected humans demonstrated that the As12 ELISA was able to detect long-term exposure to Ascaris with a high diagnostic sensitivity (98.4% and 92%, respectively) and specificity (95.5% and 90.0%) in pigs and humans, respectively. Conclusions/Significance These findings show the presence of a highly stage specific, glycolipid-like component (As12) that is actively secreted by infectious Ascaris larvae and which acts as a major antibody

  6. A Phosphorylcholine-Containing Glycolipid-like Antigen Present on the Surface of Infective Stage Larvae of Ascaris spp. Is a Major Antibody Target in Infected Pigs and Humans.

    Science.gov (United States)

    Vlaminck, Johnny; Masure, Dries; Wang, Tao; Nejsum, Peter; Hokke, Cornelis H; Geldhof, Peter

    2016-12-01

    The pig parasite Ascaris suum plays and important role in veterinary medicine and represents a suitable model for A. lumbricoides, which infects over 800 million people. In pigs, continued exposure to Ascaris induces immunity at the level of the gut, protecting the host against migrating larvae. The objective of this study was to identify and characterize parasite antigens targeted by this local immune response that may be crucial for parasite invasion and establishment and to evaluate their protective and diagnostic potential. Pigs were immunized by trickle infection for 30 weeks, challenged with 2,000 eggs at week 32 and euthanized two weeks after challenge. At necropsy, there was a 100% reduction in worms recovered from the intestine and a 97.2% reduction in liver white spots in comparison with challenged non-immune control animals. Antibodies purified from the intestinal mucus or from the supernatant of cultured antibody secreting cells from mesenteric lymph nodes of immune pigs were used to probe L3 extracts to identify antibody targets. This resulted in the recognition of a 12kDa antigen (As12) that is actively shed from infective Ascaris L3. As12 was characterized as a phosphorylcholine-containing glycolipid-like antigen that is highly resistant to different enzymatic and chemical treatments. Vaccinating pigs with an As12 fraction did not induce protective immunity to challenge infection. However, serological analysis using sera or plasma from experimentally infected pigs or naturally infected humans demonstrated that the As12 ELISA was able to detect long-term exposure to Ascaris with a high diagnostic sensitivity (98.4% and 92%, respectively) and specificity (95.5% and 90.0%) in pigs and humans, respectively. These findings show the presence of a highly stage specific, glycolipid-like component (As12) that is actively secreted by infectious Ascaris larvae and which acts as a major antibody target in infected humans and pigs.

  7. A Phosphorylcholine-Containing Glycolipid-like Antigen Present on the Surface of Infective Stage Larvae of Ascaris spp. Is a Major Antibody Target in Infected Pigs and Humans.

    Directory of Open Access Journals (Sweden)

    Johnny Vlaminck

    2016-12-01

    Full Text Available The pig parasite Ascaris suum plays and important role in veterinary medicine and represents a suitable model for A. lumbricoides, which infects over 800 million people. In pigs, continued exposure to Ascaris induces immunity at the level of the gut, protecting the host against migrating larvae. The objective of this study was to identify and characterize parasite antigens targeted by this local immune response that may be crucial for parasite invasion and establishment and to evaluate their protective and diagnostic potential.Pigs were immunized by trickle infection for 30 weeks, challenged with 2,000 eggs at week 32 and euthanized two weeks after challenge. At necropsy, there was a 100% reduction in worms recovered from the intestine and a 97.2% reduction in liver white spots in comparison with challenged non-immune control animals. Antibodies purified from the intestinal mucus or from the supernatant of cultured antibody secreting cells from mesenteric lymph nodes of immune pigs were used to probe L3 extracts to identify antibody targets. This resulted in the recognition of a 12kDa antigen (As12 that is actively shed from infective Ascaris L3. As12 was characterized as a phosphorylcholine-containing glycolipid-like antigen that is highly resistant to different enzymatic and chemical treatments. Vaccinating pigs with an As12 fraction did not induce protective immunity to challenge infection. However, serological analysis using sera or plasma from experimentally infected pigs or naturally infected humans demonstrated that the As12 ELISA was able to detect long-term exposure to Ascaris with a high diagnostic sensitivity (98.4% and 92%, respectively and specificity (95.5% and 90.0% in pigs and humans, respectively.These findings show the presence of a highly stage specific, glycolipid-like component (As12 that is actively secreted by infectious Ascaris larvae and which acts as a major antibody target in infected humans and pigs.

  8. COLONOSCOPY AND CARCINOEMBRYONIC ANTIGEN VARIATIONS

    Directory of Open Access Journals (Sweden)

    Rita G SOUSA

    2014-03-01

    Full Text Available Context Colonoscopy is essential for synchronous and metachronous cancer detection. Carcinoembryonic antigen is a colorectal cancer tumor marker, important as a follow-up tool in patients with previous colorectal cancer. False-positive carcinoembryonic antigen elevation results in multiples exams and in patient anxiety. In literature, there is reference to transient carcinoembryonic antigen increase with colonoscopy. Objective To evaluate the influence of bowel preparation and colonoscopy in carcinoembryonic antigen blood levels. Methods We prospectively studied subjects that underwent routine colonoscopy in our institution. Blood samples were collected (1 before bowel cleaning, (2 before colonoscopy and (3 immediately after colonoscopy. Blood carcinoembryonic antigen levels were determined by “Sandwich” immunoassay. The statistical methods used were the paired t-test and ANOVA. Results Thirty-seven patients (22M/15F were included; age range 28-84 (mean 56 years. Mean carcinoembryonic antigen values were 1.9, 2 and 1.8 for (1, (2 and (3, respectively. An increase in value (2 compared with (1 was observed in 20/37 patients (P = 0.018, mainly in younger patients and in patients requiring more endoluminal interventions. In 29/37 patients, the CEA value decreased from (2 to (3 (P = 1.3x10-7. Conclusions A trend for carcinoembryonic antigen increase after bowel cleaning was observed, especially in younger patients and in patients with more endoluminal interventions, but without clinical meaning.

  9. Colonoscopy and carcinoembryonic antigen variations.

    Science.gov (United States)

    Sousa, Rita G; Nunes, Ana; Meira, Tânia; Carreira, Olga; Pires, Ana M; Freitas, João

    2014-01-01

    Colonoscopy is essential for synchronous and metachronous cancer detection. Carcinoembryonic antigen is a colorectal cancer tumor marker, important as a follow-up tool in patients with previous colorectal cancer. False-positive carcinoembryonic antigen elevation results in multiples exams and in patient anxiety. In literature, there is reference to transient carcinoembryonic antigen increase with colonoscopy. To evaluate the influence of bowel preparation and colonoscopy in carcinoembryonic antigen blood levels. We prospectively studied subjects that underwent routine colonoscopy in our institution. Blood samples were collected (1) before bowel cleaning, (2) before colonoscopy and (3) immediately after colonoscopy. Blood carcinoembryonic antigen levels were determined by "Sandwich" immunoassay. The statistical methods used were the paired t-test and ANOVA. Thirty-seven patients (22M/15F) were included; age range 28-84 (mean 56 years). Mean carcinoembryonic antigen values were 1.9, 2 and 1.8 for (1), (2) and (3), respectively. An increase in value (2) compared with (1) was observed in 20/37 patients (P = 0.018), mainly in younger patients and in patients requiring more endoluminal interventions. In 29/37 patients, the CEA value decreased from (2) to (3) (P = 1.3x10-7). A trend for carcinoembryonic antigen increase after bowel cleaning was observed, especially in younger patients and in patients with more endoluminal interventions, but without clinical meaning.

  10. Antigenic relationships among four herpesviruses.

    Science.gov (United States)

    Blue, W T; Plummer, G

    1973-06-01

    Common viral antigens were detected, by fluorescent-antibody studies, in cells infected with herpes simplex virus 1, squirrel monkey herpesvirus 1, bovine rhinotracheitis, and equine abortion viruses. The two primate viruses showed slight cross-neutralization.

  11. HLA-B27 antigen

    Science.gov (United States)

    Human leukocyte antigen B27; Ankylosing spondylitis-HLA; Psoriatic arthritis-HLA; Reactive arthritis-HLA ... Erythrocyte sedimentation rate ( ESR ) Rheumatoid factor X-rays HLA testing is also used to match donated tissue ...

  12. Epicutaneous sensitization with protein antigen

    Directory of Open Access Journals (Sweden)

    I-Lin Liu

    2012-12-01

    Full Text Available In the past few decades there has been a progressive understanding that epicutaneous sensitization with protein antigen is an important sensitization route in patients with atopic dermatitis. A murine protein-patch model has been established, and an abundance of data has been obtained from experiments using this model. This review discusses the characteristics of epicutaneous sensitization with protein antigen, the induced immune responses, the underlying mechanisms, and the therapeutic potential.

  13. Effective antigen presentation to helper T cells by human eosinophils.

    Science.gov (United States)

    Farhan, Ruhaifah K; Vickers, Mark A; Ghaemmaghami, Amir M; Hall, Andrew M; Barker, Robert N; Walsh, Garry M

    2016-12-01

    Although eosinophils are inflammatory cells, there is increasing attention on their immunomodulatory roles. For example, murine eosinophils can present antigen to CD4 + T helper (Th) cells, but it remains unclear whether human eosinophils also have this ability. This study determined whether human eosinophils present a range of antigens, including allergens, to activate Th cells, and characterized their expression of MHC class II and co-stimulatory molecules required for effective presentation. Human peripheral blood eosinophils purified from non-allergic donors were pulsed with the antigens house dust mite extract (HDM), Timothy Grass extract (TG) or Mycobacterium tuberculosis purified protein derivative (PPD), before co-culture with autologous CD4 + Th cells. Proliferative and cytokine responses were measured, with eosinophil expression of HLA-DR/DP/DQ and the co-stimulatory molecules CD40, CD80 and CD86 determined by flow cytometry. Eosinophils pulsed with HDM, TG or PPD drove Th cell proliferation, with the response strength dependent on antigen concentration. The cytokine responses varied with donor and antigen, and were not biased towards any particular Th subset, often including combinations of pro- and anti-inflammatory cytokines. Eosinophils up-regulated surface expression of HLA-DR/DP/DQ, CD80, CD86 and CD40 in culture, increases that were sustained over 5 days when incubated with antigens, including HDM, or the major allergens it contains, Der p I or Der p II. Human eosinophils can, therefore, act as effective antigen-presenting cells to stimulate varied Th cell responses against a panel of antigens including HDM, TG or PPD, an ability that may help to determine the development of allergic disease. © 2016 John Wiley & Sons Ltd.

  14. Molecular typing of human platelet and neutrophil antigens (HPA and HNA)

    NARCIS (Netherlands)

    Veldhuisen, Barbera; Porcelijn, Leendert; Ellen van der Schoot, C.; de Haas, Masja

    2014-01-01

    Genotyping is an important tool in the diagnosis of disorders involving allo-immunisation to antigens present on the membranes of platelets and neutrophils. To date 28 human platelet antigens (HPAs) have been indentified on six polymorphic glycoproteins on the surface of platelets. Antibodies

  15. A Phosphorylcholine-Containing Glycolipid-like Antigen Present on the Surface of Infective Stage Larvae of Ascaris spp. Is a Major Antibody Target in Infected Pigs and Humans

    DEFF Research Database (Denmark)

    Vlaminck, Johnny; Masure, Dries; Wang, Tao

    2016-01-01

    Background The pig parasite Ascaris suum plays and important role in veterinary medicine and represents a suitable model for A. lumbricoides, which infects over 800 million people. In pigs, continued exposure to Ascaris induces immunity at the level of the gut, protecting the host against migrating...... larvae. The objective of this study was to identify and characterize parasite antigens targeted by this local immune response that may be crucial for parasite invasion and establishment and to evaluate their protective and diagnostic potential. Methodology/Principal Findings Pigs were immunized...... by trickle infection for 30 weeks, challenged with 2,000 eggs at week 32 and euthanized two weeks after challenge. At necropsy, there was a 100% reduction in worms recovered from the intestine and a 97.2% reduction in liver white spots in comparison with challenged non-immune control animals. Antibodies...

  16. The persistence ofhepatitis B antigen in the bloodtneal of the ...

    African Journals Online (AJOL)

    Abstract The persistence of the hepatitis B virus surface antigen (HBsAg) was used as an index of the sur- vival tim.e ofthis virus within the gastro-intestinal tract of the potential southern African medicinal leech, Asiaticobdella buntonensis. HBsAg was tested for in blood/faecal material at five intervals over 15 weeks. Samples ...

  17. Prevalence of hepatitis B antigen and C antibody among blood ...

    African Journals Online (AJOL)

    The prevalence of hepatitis B surface antigen (HBsAg) and hepatitis C (HCV) antibody were determined in 560 blood donor sera using ELISA kits (DIALAB Austria). Out of these 48(8.57%) were positive to hepatitis B virus infection, while 33(5.89%) were positive to hepatitis C virus antibodies. The sex distribution of ...

  18. Microbial antigenic variation mediated by homologous DNA recombination

    NARCIS (Netherlands)

    C. Vink (Cornelis); L. Rudenko (Larisa); H.S. Seifert (H. Steven)

    2012-01-01

    textabstractPathogenic microorganisms employ numerous molecular strategies in order to delay or circumvent recognition by the immune system of their host. One of the most widely used strategies of immune evasion is antigenic variation, in which immunogenic molecules expressed on the surface of a

  19. An MHC-restricted antibody-based chimeric antigen receptor requires TCR-like affinity to maintain antigen specificity

    Directory of Open Access Journals (Sweden)

    Marcela V Maus

    2016-01-01

    Full Text Available Chimeric antigen receptors (CARs are synthetic receptors that usually redirect T cells to surface antigens independent of human leukocyte antigen (HLA. Here, we investigated a T cell receptor-like CAR based on an antibody that recognizes HLA-A*0201 presenting a peptide epitope derived from the cancer-testis antigen NY-ESO-1. We hypothesized that this CAR would efficiently redirect transduced T cells in an HLA-restricted, antigen-specific manner. However, we found that despite the specificity of the soluble Fab, the same antibody in the form of a CAR caused moderate lysis of HLA-A2 expressing targets independent of antigen owing to T cell avidity. We hypothesized that lowering the affinity of the CAR for HLA-A2 would improve its specificity. We undertook a rational approach of mutating residues that, in the crystal structure, were predicted to stabilize binding to HLA-A2. We found that one mutation (DN lowered the affinity of the Fab to T cell receptor-range and restored the epitope specificity of the CAR. DN CAR T cells lysed native tumor targets in vitro, and, in a xenogeneic mouse model implanted with two human melanoma lines (A2+/NYESO+ and A2+/NYESO−, DN CAR T cells specifically migrated to, and delayed progression of, only the HLA-A2+/NY-ESO-1+ melanoma. Thus, although maintaining MHC-restricted antigen specificity required T cell receptor-like affinity that decreased potency, there is exciting potential for CARs to expand their repertoire to include a broad range of intracellular antigens.

  20. Identification and localization of a soluble antigen, Ag2, of 136 kDa from Plasmodium falciparum in vitro cultures

    DEFF Research Database (Denmark)

    Jakobsen, P H; Grellier, P; Theander, T G

    1991-01-01

    The soluble antigens, antigen 2 (Ag2) and antigen 6 (Ag6), were copurified from supernatants of P. falciparum in vitro cultures by affinity chromatography and Fast Protein Liquid Chromatography. Rabbit antibodies to Ag2 were raised and characterized by crossed immunoelectrophoresis. Ag2 appeared...... as a duplet with molecular masses of 136 and 120 kDa when tested by immunoblotting. Immunoprecipitation experiments on Triton X-100 extracted antigens from synchronized cultures showed that the antigen was synthesized in the schizont stage. Ag2 was located near the surface of schizonts in the parasitophorous...

  1. Human sensitization to Ganoderma antigen.

    Science.gov (United States)

    Tarlo, S M; Bell, B; Srinivasan, J; Dolovich, J; Hargreave, F E

    1979-07-01

    Continuous air sampling with a Hirst volumetric spore trap over 3 yr has identified basidiospores of Ganoderma applanatum, a bracket fungus, as the most numerous fungal spores in two southern Ontario locations. The particle size is small and the calculated total spore mass approximates that of the spores of Cladosporium and Alternaria. Extracts of Ganoderma applanatum bracket fungus and spores in w/v, 1:10 concentration were prepared after collection of samples of the fungus from local woods. Skin prick tests with the extracts were performed in 294 consecutive children and adults attending two chest/allergy clinics. Of these patients, 182 (61.9%) reacted to 1 or more of the common inhalant allergen extracts and 24 (8.2%) reacted to Ganoderma antigen. There was no consistent relationship between reactivity to Ganoderma antigen and any of the common inhaled allergens. IgE-dependent sensitization to Ganoderma was confirmed by the radioallergosorbent test (RAST). Rabbit antisera to Ganoderma antigen preparations did not appear to cross-react with preparations of the various clinically important allergens. The findings indicate that Ganoderma antigen is commonly encountered, can induce human sensitization, and has unique antigenicity among common allergens of clinical importance.

  2. Chimeric antigen receptor T-cell therapy for solid tumors

    Directory of Open Access Journals (Sweden)

    Kheng Newick

    2016-01-01

    Full Text Available Chimeric antigen receptor (CAR T cells are engineered constructs composed of synthetic receptors that direct T cells to surface antigens for subsequent elimination. Many CAR constructs are also manufactured with elements that augment T-cell persistence and activity. To date, CAR T cells have demonstrated tremendous success in eradicating hematological malignancies (e.g., CD19 CARs in leukemias. This success is not yet extrapolated to solid tumors, and the reasons for this are being actively investigated. Here in this mini-review, we discuss some of the key hurdles encountered by CAR T cells in the solid tumor microenvironment.

  3. Distribution of red blood cell antigens in drug-resistant and drug ...

    African Journals Online (AJOL)

    sofo

    Kramnik , 2000; Gra, 2010; Abel,. 2000). Among the various factors that contribute to a person's genetic individuality are antigens that are the major alloantigen in humans, attached to surface of red blood cells and naturally occurring antibodies ...

  4. Characterisation of Sarcoptes scabiei antigens.

    Science.gov (United States)

    Hejduk, Gloria; Hofstätter, Katja; Löwenstein, Michael; Peschke, Roman; Miller, Ingrid; Joachim, Anja

    2011-02-01

    In pig herds, the status of Sarcoptes scabiei infections is routinely monitored by serodiagnosis. Crude antigen for ELISA is usually prepared from S. scabiei var. canis or other variations and may lead to variations in the outcome of different tests, making assay standardisation difficult. This study was performed to investigate the antigen profiles of S. scabiei, including differences between hydrophilic and more hydrophobic protein fractions, by Western blotting with sera from pigs with defined infection status. Potential cross-reactivity among S. scabiei (var. canis, suis and bovis), Dermatophagoides farinae and Tyrophagus putrescentiae was also analysed. Hydrophobic S. scabiei antigens were detectable in the range of 40-50 kDa, whilst the hydrophilic fraction showed no specific antigenicity. In the hydrophobic fractions of D. farinae and T. putrescentiae, two major protein fractions in a similar size range could be identified, but no cross-reactivity with Sarcoptes-positive sera was detectable. However, examination of the hydrophilic fractions revealed cross-reactivity between Sarcoptes-positive sera and both the house dust mite and the storage mite in the range of 115 and 28/38 kDa. Specific bands in the same range (42 and 48 kDa) could be detected in blots from hydrophobic fractions of all three tested variations of S. scabiei (var. canis, bovis and suis). These results show that there are considerable differences in mange antibody reactivity, including reactions with proteins from free-living mites, which may interfere with tests based on hydrophilic antigens. Further refinement of antigen and the use of specific hydrophobic proteins could improve ELISA performance and standardisation.

  5. [Farmer's lung antigens in Germany].

    Science.gov (United States)

    Sennekamp, J; Joest, M; Sander, I; Engelhart, S; Raulf-Heimsoth, M

    2012-05-01

    Recent studies suggest that besides the long-known farmer's lung antigen sources Saccharopolyspora rectivirgula (Micropolyspora faeni), Thermoactinomyces vulgaris, and Aspergillus fumigatus, additionally the mold Absidia (Lichtheimia) corymbifera as well as the bacteria Erwinia herbicola (Pantoea agglomerans) and Streptomyces albus may cause farmer's lung in Germany. In this study the sera of 64 farmers with a suspicion of farmer's lung were examined for the following further antigens: Wallemia sebi, Cladosporium herbarum, Aspergillus versicolor, and Eurotium amstelodami. Our results indicate that these molds are not frequent causes of farmer's lung in Germany. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Potent antigen-specific immune response induced by infusion of spleen cells coupled with succinimidyl-4-(N-maleimidomethyl cyclohexane)-1-carboxylate (SMCC) conjugated antigens.

    Science.gov (United States)

    Guo, Yixian; Werbel, Tyler; Wan, Suigui; Wu, Haitao; Li, Yaohua; Clare-Salzler, Michael; Xia, Chang-Qing

    2016-02-01

    In the present study, we report our recently developed new approach to inducing antigen-specific immune response. We use two nucleophilic substitution "click" chemistry processes to successfully couple protein antigens or peptides to mouse spleen cells or T cells by a heterobifunctional crosslinker, succinimidyl-4-(N-maleimidomethyl cyclohexane)-1-carboxylate (SMCC) or sulfo-SMCC. SMCC and its water-soluble analog sulfo-SMCC contain N-hydroxysuccinimide (NHS) ester and maleimide groups, which allow stable covalent conjugation of amine- and sulfhydryl-containing molecules in trans. Protein coupling to cells relies on the free sulfhydryls (thiols) on cell surfaces and the free amines on protein antigens. Although the amount of protein coupled to cells is limited due to the limited number of cell surface thiols, the injection of spleen cells coupled with antigenic proteins, such as keyhole limpet hemocyanin (KLH) or ovalbumin (OVA), induces a potent antigen-specific immune response in vivo, which is even stronger than that induced by the injection of a large dose of protein plus adjuvants. In addition, short peptides coupled to purified splenic T cells also potently elicit peptide-specific T cell proliferation in vivo after injection. Further studies show that antigen-coupled spleen cell treatment leads to augmented IFN-γ-producing T cells. Our study provides a unique antigen delivery method that efficiently distributes antigen to the entire immune system, subsequently eliciting a potent antigen-specific immune response with enhanced IFN-γ production. The findings in the present study suggest that this antigen-cell coupling strategy could be employed in immunotherapy for cancers, infectious diseases as well as immune-mediated disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Antigen processing and immune regulation in the response to tumours.

    Science.gov (United States)

    Reeves, Emma; James, Edward

    2017-01-01

    The MHC class I and II antigen processing and presentation pathways display peptides to circulating CD8 + cytotoxic and CD4 + helper T cells respectively to enable pathogens and transformed cells to be identified. Once detected, T cells become activated and either directly kill the infected / transformed cells (CD8 + cytotoxic T lymphocytes) or orchestrate the activation of the adaptive immune response (CD4 + T cells). The immune surveillance of transformed/tumour cells drives alteration of the antigen processing and presentation pathways to evade detection and hence the immune response. Evasion of the immune response is a significant event tumour development and considered one of the hallmarks of cancer. To avoid immune recognition, tumours employ a multitude of strategies with most resulting in a down-regulation of the MHC class I expression at the cell surface, significantly impairing the ability of CD8 + cytotoxic T lymphocytes to recognize the tumour. Alteration of the expression of key players in antigen processing not only affects MHC class I expression but also significantly alters the repertoire of peptides being presented. These modified peptide repertoires may serve to further reduce the presentation of tumour-specific/associated antigenic epitopes to aid immune evasion and tumour progression. Here we review the modifications to the antigen processing and presentation pathway in tumours and how it affects the anti-tumour immune response, considering the role of tumour-infiltrating cell populations and highlighting possible future therapeutic targets. © 2016 John Wiley & Sons Ltd.

  8. Viral immune evasion: Lessons in MHC class I antigen presentation.

    Science.gov (United States)

    van de Weijer, Michael L; Luteijn, Rutger D; Wiertz, Emmanuel J H J

    2015-03-01

    The MHC class I antigen presentation pathway enables cells infected with intracellular pathogens to signal the presence of the invader to the immune system. Cytotoxic T lymphocytes are able to eliminate the infected cells through recognition of pathogen-derived peptides presented by MHC class I molecules at the cell surface. In the course of evolution, many viruses have acquired inhibitors that target essential stages of the MHC class I antigen presentation pathway. Studies on these immune evasion proteins reveal fascinating strategies used by viruses to elude the immune system. Viral immunoevasins also constitute great research tools that facilitate functional studies on the MHC class I antigen presentation pathway, allowing the investigation of less well understood routes, such as TAP-independent antigen presentation and cross-presentation of exogenous proteins. Viral immunoevasins have also helped to unravel more general cellular processes. For instance, basic principles of ER-associated protein degradation via the ubiquitin-proteasome pathway have been resolved using virus-induced degradation of MHC class I as a model. This review highlights how viral immunoevasins have increased our understanding of MHC class I-restricted antigen presentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. СAPSULAR ANTIGEN OF YERSINIA PESTIS

    Directory of Open Access Journals (Sweden)

    L. A. Kadnikova

    2015-01-01

    Full Text Available Plague is a zoonosis caused by gram-negative bacteria Yersinia pestis, which, as a rule, is transmitted to humans from septicemic rodents by the bites of infected fleas. This microbe killed more people than all of the wars in the human history. Y. pestis circulation in the natural plague foci is ensured by the whole number of pathogenicity factors with differing functional orientation. This review is devoted to one of them, Y. pestis capsular antigen (F1 or Caf1. The history of its discovery and studying of its genetic control, biosynthesis, isolation and purification, and physicochemical properties are reviewed. Its roles in plague pathogenesis and its application as a main component of plague vaccines are also discussed. Y. pestis capsule under light microscopy is visually amorphous, while high-resolution electron microscopy displays the structure formed from separate fimbria-like cords up to 200 nm long, diverging from the bacterial surface in different directions. At 37°C Y. pestis produce 800–1000 times more capsular antigen than at 28°C. Genes coding for 17.6-kD Caf1 protein, which contains 170 amino acids, are located in caf1 operon of pFra plasmid. Analysis of caf1 operon nucleotide sequence testified its close phylogenetic relationship with the gene clusters coding for pilus adhesins that were secreted with the help of chaperone/usher systems in enterobacteria including six additional adhesins in Y. pestis. Y. pestis multiplication within macrophages is the obligatory stage of plague pathogenesis, and the plague pathogen virulence correlates not with resistance to phagocyte ingesting but with bacterial ability to survive and multiply within phagolysosomes of phagocytes due to neutralization of antibacterial functions of eukaryotic cells. The capsule formed out of the Caf1 aggregates protects Y. pestis from ingestion by naïve host’s phagocytes and prevents from initiation of the alternative pathway of the complement system

  10. Natural selection promotes antigenic evolvability

    NARCIS (Netherlands)

    Graves, C.J.; Ros, V.I.D.; Stevenson, B.; Sniegowski, P.D.; Brisson, D.

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide

  11. Predicting influenza antigenicity from Hemagglutintin sequence data based on a joint random forest method.

    Science.gov (United States)

    Yao, Yuhua; Li, Xianhong; Liao, Bo; Huang, Li; He, Pingan; Wang, Fayou; Yang, Jiasheng; Sun, Hailiang; Zhao, Yulong; Yang, Jialiang

    2017-05-08

    Timely identification of emerging antigenic variants is critical to influenza vaccine design. The accuracy of a sequence-based antigenic prediction method relies on the choice of amino acids substitution matrices. In this study, we first compared a comprehensive 95 substitution matrices reflecting various amino acids properties in predicting the antigenicity of influenza viruses by a random forest model. We then proposed a novel algorithm called joint random forest regression (JRFR) to jointly consider top substitution matrices. We applied JRFR to human H3N2 seasonal influenza data from 1968 to 2003. A 10-fold cross-validation shows that JRFR outperforms other popular methods in predicting antigenic variants. In addition, our results suggest that structure features are most relevant to influenza antigenicity. By restricting the analysis to data involving two adjacent antigenic clusters, we inferred a few key amino acids mutation driving the 11 historical antigenic drift events, pointing to experimentally validated mutations. Finally, we constructed an antigenic cartography of all H3N2 viruses with hemagglutinin (the glycoprotein on the surface of the influenza virus responsible for its binding to host cells) sequence available from NCBI flu database, and showed an overall correspondence and local inconsistency between genetic and antigenic evolution of H3N2 influenza viruses.

  12. Comparative analysis of the humoral immune response to Moraxella catarrhalis and Streptococcus pneumoniae surface antigens in children suffering from recurrent acute otitis media and chronic otitis media with effusion.

    NARCIS (Netherlands)

    Verhaegh, S.J.; Stol, K.; Vogel, C.P. de; Riesbeck, K.; Lafontaine, E.R.; Murphy, T.F.; Belkum, A. van; Hermans, P.W.M.; Hays, J.P.

    2012-01-01

    A prospective clinical cohort study was established to investigate the humoral immune response in middle ear fluids (MEF) and serum against bacterial surface proteins in children suffering from recurrent acute otitis media (rAOM) and chronic otitis media with effusion (COME), using Luminex xMAP

  13. Comparative analysis of the humoral immune response to Moraxella catarrhalis and Streptococcus pneumoniae surface antigens in children suffering from recurrent acute otitis media and chronic otitis media with effusion

    NARCIS (Netherlands)

    S.J.C. Verhaegh (Suzanne); K. Stol (Kim); C.P. de Vogel (Corné); K. Riesbeck (Kristian); E.R. Lafontaine (Eric); T.F. Murphy (Timothy); A.F. van Belkum (Alex); P.W.M. Hermans (Peter); J.P. Hays (John)

    2012-01-01

    textabstractA prospective clinical cohort study was established to investigate the humoral immune response in middle ear fluids (MEF) and serum against bacterial surface proteins in children suffering from recurrent acute otitis media (rAOM) and chronic otitis media with effusion (COME), using

  14. Concepts and applications for influenza antigenic cartography

    Science.gov (United States)

    Cai, Zhipeng; Zhang, Tong; Wan, Xiu-Feng

    2011-01-01

    Influenza antigenic cartography projects influenza antigens into a two or three dimensional map based on immunological datasets, such as hemagglutination inhibition and microneutralization assays. A robust antigenic cartography can facilitate influenza vaccine strain selection since the antigenic map can simplify data interpretation through intuitive antigenic map. However, antigenic cartography construction is not trivial due to the challenging features embedded in the immunological data, such as data incompleteness, high noises, and low reactors. To overcome these challenges, we developed a computational method, temporal Matrix Completion-Multidimensional Scaling (MC-MDS), by adapting the low rank MC concept from the movie recommendation system in Netflix and the MDS method from geographic cartography construction. The application on H3N2 and 2009 pandemic H1N1 influenza A viruses demonstrates that temporal MC-MDS is effective and efficient in constructing influenza antigenic cartography. The web sever is available at http://sysbio.cvm.msstate.edu/AntigenMap. PMID:21761589

  15. Hepatitis B Virus Infection and Hepatocellular Carcinoma: Correlation Between IgM Antibody to Hepatitis B Core Antigen, Hepatitis B e Antigen, and Hepatitis B DNA

    Science.gov (United States)

    1988-01-01

    Mdicine and ni)giene HEPATITIS B VIRUS INFECTION AND HEPATOCELLULAR CARCINOMA: CORRELATION BETWEEN IgM ANTIBODY TO HEPATITIS B CORE ANTIGEN, HEPATITIS B e...ANTIGEN, AND HEPATITIS B DNA MARIA H. SJOGREN.* GEOFFREY M. DUSHEIKO. MICHAEL C. KEW, AND ERNEST SONG *Depart,ent of Virus Diseases, valter Reed Arny...Johannesburg, South Africa Abstract. Sera from 102 black patients with primary hepatocellular carcinoma (PHC) and hepatitis B surface antigenemia

  16. Antibody response dynamics to the Plasmodium falciparum conserved vaccine candidate antigen, merozoite surface protein-1 C-terminal 19kD (MSP1-19kD, in Peruvians exposed to hypoendemic malaria transmission

    Directory of Open Access Journals (Sweden)

    Gamboa Dionicia

    2008-09-01

    Full Text Available Abstract Background In high-transmission areas, developing immunity to symptomatic Plasmodium falciparum infections requires 2–10 years of uninterrupted exposure. Delayed malaria-immunity has been attributed to difficult-to-develop and then short-lived antibody responses. Methods In a study area with P. falciparum infections/person/year, antibody responses to the MSP1-19kD antigen were evaluated and associations with P. falciparum infections in children and adults. In months surrounding and during the malaria seasons of 2003–2004, 1,772 participants received ≥6 active visits in one study-year. Community-wide surveys were conducted at the beginning and end of each malaria season, and weekly active visits were completed for randomly-selected individuals each month. There were 79 P. falciparum infections with serum samples collected during and approximately one month before and after infection. Anti-MSP1-19kD IgG levels were measured by ELISA. Results The infection prevalence during February-July was similar in children (0.02–0.12 infections/person/month and adults (0.03–0.14 infections/person/month and was negligible in the four-month dry season. In children and adults, the seroprevalence was maintained in the beginning (children = 28.9%, adults = 61.8% versus ending malaria-season community survey (children = 26.7%, adults = 64.6%. Despite the four-month non-transmission season, the IgG levels in Plasmodium-negative adults were similar to P. falciparum-positive adults. Although children frequently responded upon infection, the transition from a negative/low level before infection to a high level during/after infection was slower in children. Adults and children IgG-positive before infection had reduced symptoms and parasite density. Conclusion Individuals in low transmission areas can rapidly develop and maintain αMSP1-19kD IgG responses for >4 months, unlike responses reported in high transmission study areas. A greater immune

  17. Screening Donors for Rare Antigen Constellations.

    Science.gov (United States)

    Wagner, Franz F

    2009-01-01

    SCREENING BLOOD DONORS FOR RARE ANTIGEN CONSTELLATIONS HAS BEEN IMPLEMENTED USING SIMPLE PCR METHODS: PCR with enzyme digestion has been used to type donor cohorts for Dombrock antigens, and PCR with sequence-specific priming to identify donors negative for antigens of high frequency. The advantages and disadvantages of the methods as well as their current state is discussed.

  18. Identification of a peptide binding protein that plays a role in antigen presentation

    International Nuclear Information System (INIS)

    Lakey, E.K.; Margoliash, E.; Pierce, S.K.

    1987-01-01

    The helper T-cell response to globular proteins appears, in general, to require intracellular processing of the antigen, such that a peptide fragment containing the T-cell antigenic determinant is released and transported to and held on the surface of an Ia-expressing, antigen-presenting cell. However, the molecular details underlying these phenomena are largely unknown. The means by which antigenic peptides are anchored on the antigen-presenting cell surface was investigated. A cell surface protein is identified that was isolated by it ability to bind to a 24-amino acid peptide fragment of pigeon cytochrome c, residues 81-104, containing the major antigenic determinant for B10.A mouse T cells. This peptide binding protein, purified from [ 35 S]methionine-labeled cells, appears as two discrete bands of ≅72 and 74 kDa after NaDodSO 4 /PAGE. The protein can be eluted from the peptide affinity column with equivalent concentrations of either the antigenic pigeon cytochrome c peptide or the corresponding nonantigenic peptide of mouse cytochrome c. However, it does not bind to the native cytochromes c, either of pigeon or mouse, and thus the protein appears to recognize some structure available only in the free peptides. This protein plays a role in antigen presentation. Its expression is not major histocompatibility complex-restricted in that the blocking activity of the antisera can be absorbed on spleen cells from mice of different haplotypes. This peptide binding protein can be isolated from a variety of cell types, including B cells, T cells, and fibroblasts. The anchoring of processed peptides on the cell surface by such a protein may play a role in antigen presentation

  19. Cell wall anchoring of the Campylobacter antigens to Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Patrycja Anna Kobierecka

    2016-02-01

    Full Text Available Campylobacter jejuni is the most frequent cause of human food-borne gastroenteritis and chicken meat is the main source of infection. Recent studies showed that broiler chicken immunization against Campylobacter should be the most efficient way to lower the number of human infections by this pathogen. Induction of the mucosal immune system after oral antigen administration should provide protective immunity to chickens. In this work we tested the usefulness of Lactococcus lactis, the most extensively studied lactic acid bacterium, as a delivery vector for Campylobacter antigens. First we constructed hybrid protein – CjaA antigen presenting CjaD peptide epitopes on its surface. We showed that specific rabbit anti-rCjaAD serum reacted strongly with both CjaA and CjaD produced by a wild type Campylobacter jejuni strain. Next, rCjaAD and CjaA were fused to the C-terminus of the L. lactis YndF containing the LPTXG motif. The genes expressing these proteins were transcribed under control of the L. lactis Usp45 promoter and their products contain the Usp45 signal sequences. This strategy ensures a cell surface location of both analysed proteins, which was confirmed by immunofluorescence assay. In order to evaluate the impact of antigen location on vaccine prototype efficacy, a L. lactis strain producing cytoplasm-located rCjaAD was also generated. Animal experiments showed a decrease of Campylobacter cecal load in vaccinated birds as compared with the control group and showed that the L. lactis harboring the surface-exposed rCjaAD antigen afforded greater protection than the L. lactis producing cytoplasm-located rCjaAD. To the best of our knowledge, this is the first attempt to employ LAB (Lactic Acid Bacteria strains as a mucosal delivery vehicle for chicken immunization. Although the observed reduction of chicken colonization by Campylobacter resulting from vaccination was rather moderate, the experiments showed that LAB strains can be considered

  20. NovelTreponema pallidumRecombinant Antigens for Syphilis Diagnostics: Current Status and Future Prospects.

    Science.gov (United States)

    Kubanov, Aleksey; Runina, Anastassia; Deryabin, Dmitry

    2017-01-01

    The recombinant protein technology considerably promoted the development of rapid and accurate treponema-specific laboratory diagnostics of syphilis infection. For the last ten years, the immunodominant recombinant inner membrane lipoproteins are proved to be sensitive and specific antigens for syphilis screening. However, the development of an enlarged T. pallidum antigen panel for diagnostics of early and late syphilis and differentiation of syphilis stages or cured syphilis remains as actual goal of multidisciplinary expertise. Current review revealed novel recombinant antigens: surface-exposed proteins, adhesins, and periplasmic and flagellar proteins, which are promising candidates for the improved syphilis serological diagnostics. The opportunities and limitations of diagnostic usage of these antigens are discussed and the criteria for selection of optimal antigens panel summarized.

  1. Novel Treponema pallidum Recombinant Antigens for Syphilis Diagnostics: Current Status and Future Prospects

    Science.gov (United States)

    Kubanov, Aleksey; Runina, Anastassia

    2017-01-01

    The recombinant protein technology considerably promoted the development of rapid and accurate treponema-specific laboratory diagnostics of syphilis infection. For the last ten years, the immunodominant recombinant inner membrane lipoproteins are proved to be sensitive and specific antigens for syphilis screening. However, the development of an enlarged T. pallidum antigen panel for diagnostics of early and late syphilis and differentiation of syphilis stages or cured syphilis remains as actual goal of multidisciplinary expertise. Current review revealed novel recombinant antigens: surface-exposed proteins, adhesins, and periplasmic and flagellar proteins, which are promising candidates for the improved syphilis serological diagnostics. The opportunities and limitations of diagnostic usage of these antigens are discussed and the criteria for selection of optimal antigens panel summarized. PMID:28523273

  2. Toward a network model of MHC class II-restricted antigen processing

    Directory of Open Access Journals (Sweden)

    Laurence C Eisenlohr

    2013-12-01

    Full Text Available The standard model of Major Histocompatibility Complex class II (MHCII-restricted antigen processing depicts a straightforward, linear pathway: Internalized antigens are converted into peptides that load in a chaperone dependent manner onto nascent MHCII in the late endosome, the complexes subsequently trafficking to the cell surface for recognition by CD4+ T cells (TCD4+. Several variations on this theme, both moderate and radical, have come to light but these alternatives have remained peripheral, the conventional pathway generally presumed to be the primary driver of TCD4+ responses. Here we continue to press for the conceptual repositioning of these alternatives toward the center while proposing that MHCII processing be thought of less in terms of discrete pathways and more in terms of a network whose major and minor conduits are variable depending upon many factors, including the epitope, the nature of the antigen, the source of the antigen, and the identity of the antigen-presenting cell.

  3. Antigen storage compartments in mature dendritic cells facilitate prolonged cytotoxic T lymphocyte cross-priming capacity.

    Science.gov (United States)

    van Montfoort, Nadine; Camps, Marcel G; Khan, Selina; Filippov, Dmitri V; Weterings, Jimmy J; Griffith, Janice M; Geuze, Hans J; van Hall, Thorbald; Verbeek, J Sjef; Melief, Cornelis J; Ossendorp, Ferry

    2009-04-21

    Dendritic cells (DCs) are crucial for priming of naive CD8(+) T lymphocytes to exogenous antigens, so-called "cross-priming." We report that exogenous protein antigen can be conserved for several days in mature DCs, coinciding with strong cytotoxic T lymphocyte cross-priming potency in vivo. After MHC class I peptide elution, protein antigen-derived peptide presentation is efficiently restored, indicating the presence of an intracellular antigen depot. We characterized this depot as a lysosome-like organelle, distinct from MHC class II compartments and recently described early endosomal compartments that allow acute antigen presentation in MHC class I. The storage compartments we report here facilitate continuous supply of MHC class I ligands. This mechanism ensures sustained cross-presentation by DCs, despite the short-lived expression of MHC class I-peptide complexes at the cell surface.

  4. Identification of an Antigen from Normal Human Tissue That Crossreacts with the Carcinoembryonic Antigen

    Science.gov (United States)

    Kleist, S. Von; Chavanel, G.; Burtin, P.

    1972-01-01

    A glycoprotein present in normal human tissue is characterized that is neither organ- nor tumor-specific (nonspecific crossreacting antigen) and that crossreacts (by the Ouchterlony double-diffusion technique) with the carcinoembryonic antigen. This immunological relationship indicates common determinants on the molecules of both antigens. We demonstrate that the nonspecific crossreacting antigen is not a fragment of the carcinoembryonic antigen molecule. Images PMID:4115954

  5. Plasma antibodies from malaria-exposed pregnant women recognize variant surface antigens on em>Plasmodium falciparum-infected erythrocytes in a parity-dependent manner and block parasite adhesion to chondroitin sulfate A

    DEFF Research Database (Denmark)

    Ricke, C H; Staalsoe, T; Koram, K

    2000-01-01

    Abs from malaria-exposed multiparous women are able to interfere with binding of P. falciparum parasites to CSA in vitro, and acquisition of Abs interfering with CSA-specific parasite sequestration thus appears to be a critical element in acquired protection against PAM. Here we show that adults from...... an area of hyperendemic P. falciparum transmission generally possessed low levels of Abs specifically recognizing surface Ags expressed by a CSA-adhering parasite isolate, while unselected isolates were well recognized. In marked contrast, most third-trimester pregnant women from that area had very high...

  6. Antigenic variation in the intestinal parasite Giardia lamblia.

    Science.gov (United States)

    Gargantini, Pablo Rubén; Serradell, Marianela Del Carmen; Ríos, Diego Nicolás; Tenaglia, Albano Heraldo; Luján, Hugo Daniel

    2016-08-01

    Giardia lamblia trophozoites undergo antigenic variation, where one member of the Variant-specific Surface Protein (VSP) family is expressed on the surface of proliferating trophozoites and periodically replaced by another one. Two main questions have challenged researchers since antigenic switching was discovered in Giardia: What are the mechanisms involved? How are they influenced by other cellular processes or by the environment? Two molecular mechanisms have been proposed, both involving small non-coding RNAs. Here we postulate that (a) chromatin remodeling, triggered by environmental factors, also plays an important role in selecting the VSP that will be expressed and (b) the particular VSP structure may not only protect the parasite in the small intestine but also signal the need to exchange the existing VSP for another. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Unpolarized Release of Vaccinia Virus and HIV Antigen by Colchicine Treatment Enhances Intranasal HIV Antigen Expression and Mucosal Humoral Responses

    Science.gov (United States)

    Zhang, Yan; Yang, Jingyi; Bao, Rong; Chen, Yaoqing; Zhou, Dihan; He, Benxia; Zhong, Maohua; Li, Yaoming; Liu, Fang; Li, Qiaoli; Yang, Yi; Han, Chen; Sun, Ying; Cao, Yuan; Yan, Huimin

    2011-01-01

    The induction of a strong mucosal immune response is essential to building successful HIV vaccines. Highly attenuated recombinant HIV vaccinia virus can be administered mucosally, but even high doses of immunization have been found unable to induce strong mucosal antibody responses. In order to solve this problem, we studied the interactions of recombinant HIV vaccinia virus Tiantan strain (rVTT-gagpol) in mucosal epithelial cells (specifically Caco-2 cell layers) and in BALB/c mice. We evaluated the impact of this virus on HIV antigen delivery and specific immune responses. The results demonstrated that rVTT-gagpol was able to infect Caco-2 cell layers and both the nasal and lung epithelia in BALB/c mice. The progeny viruses and expressed p24 were released mainly from apical surfaces. In BALB/c mice, the infection was limited to the respiratory system and was not observed in the blood. This showed that polarized distribution limited antigen delivery into the whole body and thus limited immune response. To see if this could be improved upon, we stimulated unpolarized budding of the virus and HIV antigens by treating both Caco-2 cells and BALB/c mice with colchicine. We found that, in BALB/c mice, the degree of infection and antigen expression in the epithelia went up. As a result, specific immune responses increased correspondingly. Together, these data suggest that polarized budding limits antigen delivery and immune responses, but unpolarized distribution can increase antigen expression and delivery and thus enhance specific immune responses. This conclusion can be used to optimize mucosal HIV vaccine strategies. PMID:21935396

  8. Unpolarized release of vaccinia virus and HIV antigen by colchicine treatment enhances intranasal HIV antigen expression and mucosal humoral responses.

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    Full Text Available The induction of a strong mucosal immune response is essential to building successful HIV vaccines. Highly attenuated recombinant HIV vaccinia virus can be administered mucosally, but even high doses of immunization have been found unable to induce strong mucosal antibody responses. In order to solve this problem, we studied the interactions of recombinant HIV vaccinia virus Tiantan strain (rVTT-gagpol in mucosal epithelial cells (specifically Caco-2 cell layers and in BALB/c mice. We evaluated the impact of this virus on HIV antigen delivery and specific immune responses. The results demonstrated that rVTT-gagpol was able to infect Caco-2 cell layers and both the nasal and lung epithelia in BALB/c mice. The progeny viruses and expressed p24 were released mainly from apical surfaces. In BALB/c mice, the infection was limited to the respiratory system and was not observed in the blood. This showed that polarized distribution limited antigen delivery into the whole body and thus limited immune response. To see if this could be improved upon, we stimulated unpolarized budding of the virus and HIV antigens by treating both Caco-2 cells and BALB/c mice with colchicine. We found that, in BALB/c mice, the degree of infection and antigen expression in the epithelia went up. As a result, specific immune responses increased correspondingly. Together, these data suggest that polarized budding limits antigen delivery and immune responses, but unpolarized distribution can increase antigen expression and delivery and thus enhance specific immune responses. This conclusion can be used to optimize mucosal HIV vaccine strategies.

  9. Differential expression of the Escherichia coli autoaggregation factor antigen 43

    DEFF Research Database (Denmark)

    Schembri, Mark; Hjerrild, Louise; Gjermansen, Morten

    2003-01-01

    Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox......-forming potential of E. coli. Finally, we demonstrated that Ag43-mediated cell aggregation confers significant protection against hydrogen peroxide killing....

  10. Targeting lentiviral vectors to antigen-specific immunoglobulins.

    Science.gov (United States)

    Ziegler, Leslie; Yang, Lili; Joo, Kye il; Yang, Haiguang; Baltimore, David; Wang, Pin

    2008-09-01

    Gene transfer into B cells by lentivectors can provide an alternative approach to managing B lymphocyte malignancies and autoreactive B cell-mediated autoimmune diseases. These pathogenic B cell populations can be distinguished by their surface expression of monospecific immunoglobulin. Development of a novel vector system to deliver genes to these specific B cells could improve the safety and efficacy of gene therapy. We have developed an efficient method to target lentivectors to monospecific immunoglobulin-expressing cells in vitro and in vivo. We were able to incorporate a model antigen CD20 and a fusogenic protein derived from the Sindbis virus as two distinct molecules into the lentiviral surface. This engineered vector could specifically bind to cells expressing surface immunoglobulin recognizing CD20 (alphaCD20), resulting in efficient transduction of target cells in a cognate antigen-dependent manner in vitro, and in vivo in a xenografted tumor model. Tumor suppression was observed in vivo, using the engineered lentivector to deliver a suicide gene to a xenografted tumor expressing alphaCD20. These results show the feasibility of engineering lentivectors to target immunoglobulin- specific cells to deliver a therapeutic effect. Such targeting lentivectors also could potentially be used to genetically mark antigen-specific B cells in vivo to study their B cell biology.

  11. Identification and localization of a soluble antigen, Ag2, of 136 kDa from Plasmodium falciparum in vitro cultures

    DEFF Research Database (Denmark)

    Jakobsen, P H; Grellier, P; Theander, T G

    1991-01-01

    as a duplet with molecular masses of 136 and 120 kDa when tested by immunoblotting. Immunoprecipitation experiments on Triton X-100 extracted antigens from synchronized cultures showed that the antigen was synthesized in the schizont stage. Ag2 was located near the surface of schizonts in the parasitophorous...

  12. In Vitro Use of Autologous Dendritic Cells Improves Detection of T Cell Responses to Hepatitis B Virus (HBV) Antigens

    NARCIS (Netherlands)

    Carotenuto, Patrizia; Artsen, Andre; Niesters, Hubert G.; Osterhaus, Albert D.; Pontesilli, Oscar

    T lymphocyte responses to hepatitis B virus (HBV) core antigen (HBcAg) are vigorous and easily detectable in vitro during recovery from acute hepatitis B but significantly weaker in patients with chronic HBV infection. In contrast, T cell responses to hepatitis B surface antigen (HBsAg) are almost

  13. Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/Cd(x)Zn(1 - x)S/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen.

    Science.gov (United States)

    Shen, Huaibin; Yuan, Hang; Niu, Jin Zhong; Xu, Shasha; Zhou, Changhua; Ma, Lan; Li, Lin Song

    2011-09-16

    Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/Cd(x)Zn(1 - x)S/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/Cd(x)Zn(1 - x)S/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml( - 1).

  14. Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/CdxZn1 - xS/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen

    Science.gov (United States)

    Shen, Huaibin; Yuan, Hang; Niu, Jin Zhong; Xu, Shasha; Zhou, Changhua; Ma, Lan; Li, Lin Song

    2011-09-01

    Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/CdxZn1 - xS/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml - 1.

  15. Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/Cd{sub x}Zn{sub 1-x}S/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen

    Energy Technology Data Exchange (ETDEWEB)

    Shen Huaibin; Niu Jin Zhong; Xu Shasha; Zhou Changhua; Li Linsong [Key Laboratory for Special Functional Materials, Henan University, Kaifeng 475004 (China); Yuan Hang; Ma Lan, E-mail: malan@sz.tsinghua.edu.cn, E-mail: lsli@henu.edu.cn [Life Science Division, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2011-09-16

    Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/Cd{sub x}Zn{sub 1-x}S/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml{sup -1}.

  16. Viral sequestration of antigen subverts cross presentation to CD8(+ T cells.

    Directory of Open Access Journals (Sweden)

    Eric F Tewalt

    2009-05-01

    Full Text Available Virus-specific CD8(+ T cells (T(CD8+ are initially triggered by peptide-MHC Class I complexes on the surface of professional antigen presenting cells (pAPC. Peptide-MHC complexes are produced by two spatially distinct pathways during virus infection. Endogenous antigens synthesized within virus-infected pAPC are presented via the direct-presentation pathway. Many viruses have developed strategies to subvert direct presentation. When direct presentation is blocked, the cross-presentation pathway, in which antigen is transferred from virus-infected cells to uninfected pAPC, is thought to compensate and allow the generation of effector T(CD8+. Direct presentation of vaccinia virus (VACV antigens driven by late promoters does not occur, as an abortive infection of pAPC prevents production of these late antigens. This lack of direct presentation results in a greatly diminished or ablated T(CD8+ response to late antigens. We demonstrate that late poxvirus antigens do not enter the cross-presentation pathway, even when identical antigens driven by early promoters access this pathway efficiently. The mechanism mediating this novel means of viral modulation of antigen presentation involves the sequestration of late antigens within virus factories. Early antigens and cellular antigens are cross-presented from virus-infected cells, as are late antigens that are targeted to compartments outside of the virus factories. This virus-mediated blockade specifically targets the cross-presentation pathway, since late antigen that is not cross-presented efficiently enters the MHC Class II presentation pathway. These data are the first to describe an evasion mechanism employed by pathogens to prevent entry into the cross-presentation pathway. In the absence of direct presentation, this evasion mechanism leads to a complete ablation of the T(CD8+ response and a potential replicative advantage for the virus. Such mechanisms of viral modulation of antigen presentation

  17. Molecular typing of human platelet and neutrophil antigens (HPA and HNA).

    Science.gov (United States)

    Veldhuisen, Barbera; Porcelijn, Leendert; Ellen van der Schoot, C; de Haas, Masja

    2014-04-01

    Genotyping is an important tool in the diagnosis of disorders involving allo-immunisation to antigens present on the membranes of platelets and neutrophils. To date 28 human platelet antigens (HPAs) have been indentified on six polymorphic glycoproteins on the surface of platelets. Antibodies against HPAs play a role in foetal and neonatal alloimmune thrombocytopenia (FNAIT), post-transfusion purpura (PTP) and refractoriness to donor platelets. The 11 human neutrophil antigens (HNAs) described to date have been indentified on five polymorphic proteins on the surface of granulocytes. Antibodies to HNAs are implicated with foetal and neonatal alloimmune neutropenia (FNAIN), autoimmune neutropenia (AIN) and transfusion related acute lung injury (TRALI). In this report, we will review the molecular basis and techniques currently available for the genotyping of human platelet and neutrophil antigens. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. HIV immune evasion disruption of antigen presentation by the HIV Nef protein.

    Science.gov (United States)

    Wonderlich, Elizabeth R; Leonard, Jolie A; Collins, Kathleen L

    2011-01-01

    The Human Immunodeficiency Virus (HIV) Nef protein is necessary for high viral loads and for timely progression to AIDS. Nef plays a number of roles, but its effect on antigen presentation and immune evasion are among the best characterized. Cytotoxic T lymphocytes (CTLs) recognize and lyse virally infected cells by detecting viral antigens in complex with host major histocompatibility complex class I (MHC-I) molecules on the infected cell surface. The HIV Nef protein disrupts antigen presentation at the cell surface by interfering with the normal trafficking pathway of MHC-I and thus reduces CTL recognition and lysis of infected cells. The molecular mechanism by which Nef causes MHC-I downmodulation is becoming more clear, but some questions remain. A better understanding of how Nef disrupts antigen presentation may lead to the development of drugs that enhance the ability of the anti-HIV CTLs to control HIV disease. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Chemical camouflage of antigenic determinants: stealth erythrocytes.

    Science.gov (United States)

    Scott, M D; Murad, K L; Koumpouras, F; Talbot, M; Eaton, J W

    1997-07-08

    In a number of clinical circumstances it would be desirable to artificially conceal cellular antigenic determinants to permit survival of heterologous donor cells. A case in point is the problem encountered in transfusions of patients with rare blood types or chronically transfused patients who become allosensitized to minor blood group determinants. We have tested the possibility that chemical modification of the red blood cell (RBC) membrane might serve to occlude antigenic determinants, thereby minimizing transfusion reactions. To this end, we have covalently bound methoxy(polyethylene glycol) (mPEG) to the surface of mammalian RBC via cyanuric chloride coupling. Human RBC treated with this technique lose ABO blood group reactivity as assessed by solution-phase antisera agglutination. In accord with this, we also find a profound decrease in anti-blood group antibody binding. Furthermore, whereas human monocytes avidly phagocytose untreated sheep RBC, mPEG-derivatized sheep RBC are ineffectively phagocytosed. Surprisingly, human and mouse RBC appear unaffected by this covalent modification of the cell membrane. Thus, mPEG-treated RBC are morphologically normal, have normal osmotic fragility, and mPEG-derivatized murine RBC have normal in vivo survival, even following repeated infusions. Finally, in preliminary experiments, mPEG-modified sheep RBC intraperitoneally transfused into mice show significantly improved (up to 360-fold) survival when compared with untreated sheep RBC. We speculate that similar chemical camouflage of intact cells may have significant clinical applications in both transfusion (e.g., allosensitization and autoimmune hemolytic disease) and transplantation (e.g., endothelial cells and pancreatic beta cells) medicine.

  20. Transgenic lettuce seedlings carrying hepatitis B virus antigen HBsAg

    OpenAIRE

    Marcondes,Jackson; Hansen,Ekkehard

    2008-01-01

    The obtainment of transgenic edible plants carrying recombinant antigens is a desired issue in search for economic alternatives viewing vaccine production. Here we report a strategy for genetic transformation of lettuce plants (Lactuca sativa L.) using the surface antigen HBsAg of hepatitis B virus. Transgenic lettuce seedlings were obtained through the application of a regulated balance of plant growth regulators. Genetic transformation process was acquired by cocultivation of cotyledons wit...

  1. Antigenicity of Dermatophilus congolensis hemolysin.

    Science.gov (United States)

    Skalka, B; Pospísil, L

    1993-05-01

    The separated cell-free form of hemolytic exosubstance was obtained from five strains of Dermatophilus congolensis. Three strains produced exosubstance with high activity, two strains produced exosubstance with lower intensity of activity. The separated forms exhibited the same hemolytic interactions as the native forms produced by growing strains, namely the antagonism with staphylococcal beta hemolysin and the synergism with staphylococcal delta hemolysin, streptococcal CAMP factor and rhodococcal equi factor. Rabbit sera obtained after intravenous or intraperitoneal application of the separated forms contained precipitation and neutralization antibodies. Cross tests of precipitation and neutralization proved antigen identity of hemolysins of different D. congolensis, strains which makes the serodiagnostics of this species possible.

  2. Measurements in international units of antibody to hepatitis B surface antigen(anti-HBs) after immunization with a yeast-derived, subtype adr hepatitis B vaccine are considerably different between chemiluminescent immunoassay (CLIA) and chemiluminescent enzyme immunoassay (CLEIA).

    Science.gov (United States)

    Ogata, Norio

    2006-04-01

    The worldwide consensus of the minimum protective anti-HBs level against HBV infection is 10 mIU/mL on assays standardized by the World Health Organization (WHO) reference preparations. To investigate whether this value could be applied to recipients of yeast-derived recombinant HB vaccine containing the major surface protein of subtype adr (Bimmugen, Astellas Pharmaceutical, Tokyo), we compared anti-HBs measurements between chemiluminescent immunoassay (CLIA) (Architect Ausab, Abbott Japan, Tokyo) and chemiluminescent enzyme immunoassay (CLEIA) (Lumipulse Forte, Fujirebio, Tokyo) in given serum samples obtained from the vaccinees. The vaccine and the two assay methods are currently in a wide use in Japan. The study included 300 medical students who completed a standard vaccination course (0, 1 and 6 months). Serum samples obtained 1 month or 13 months after completing the vaccination were simultaneously tested for anti-HBs by CLIA and CLEIA. In 147 samples with quantifiable values on both CLIA and CLEIA (10 to 1000 mIU/mL) the geometric mean titer on CLEIA (225.0 mIU/mL) was significantly higher than that on CLIA (94.5 mIU/mL) (p < 0.0001). Of 26 subjects with CLIA measurements below 10 mIU/mL, 15 samples (57.7%) showed CLEIA measurements more than 10 mIU/mL. Thus, in the subtype adr-vaccinees CLEIA demonstrated considerably high serum anti-HBs measurements compared to CLIA and discordance in determining critical anti-HBs level of 10 mIU/mL was observed in more than half the samples. This suggests that the minimum HBV-protective anti HBs titer of 10 mIU/mL is difficult to be introduced to Japan where subtype adr-HB vaccines or -HBV infection are prevalent, unless characteristics of assay methods are carefully evaluated.

  3. Genetic engineering of chimeric antigen receptors using lamprey derived variable lymphocyte receptors

    Directory of Open Access Journals (Sweden)

    Robert Moot

    2016-01-01

    Full Text Available Chimeric antigen receptors (CARs are used to redirect effector cell specificity to selected cell surface antigens. Using CARs, antitumor activity can be initiated in patients with no prior tumor specific immunity. Although CARs have shown promising clinical results, the technology remains limited by the availability of specific cognate cell target antigens. To increase the repertoire of targetable tumor cell antigens we utilized the immune system of the sea lamprey to generate directed variable lymphocyte receptors (VLRs. VLRs serve as membrane bound and soluble immune effectors analogous but not homologous to immunoglobulins. They have a fundamentally different structure than immunoglobulin (Ig-based antibodies while still demonstrating high degrees of specificity and affinity. To test the functionality of VLRs as the antigen recognition domain of CARs, two VLR-CARs were created. One contained a VLR specific for a murine B cell leukemia and the other contained a VLR specific for the human T cell surface antigen, CD5. The CAR design consisted of the VLR sequence, myc-epitope tag, CD28 transmembrane domain, and intracellular CD3ζ signaling domain. We demonstrate proof of concept, including gene transfer, biosynthesis, cell surface localization, and effector cell activation for multiple VLR-CAR designs. Therefore, VLRs provide an alternative means of CAR-based cancer recognition.

  4. Isolation of Fasciola hepatica tegument antigens.

    OpenAIRE

    Hillyer, G V

    1980-01-01

    Fasciola hepatica tegument antigens were isolated from intact worms in the cold by using Nonidet P-40. Proof of the tegumental nature of the antigens was shown by the peroxidase-antiperoxidase immunocytochemical technique at the light microscope level. The potential of F. hepatica tegument antigens for the immunodiagnosis of rabbit and human fascioliasis was shown by Ouchterlony immunodiffusion, although cross-reactivity was evident in one of six serum samples from patients infected with Schi...

  5. Simultaneous identification of Trypanosoma cruzi surface and internal antigens reactive to different immunoglobulin classes (radio-immunoblotting Identificação simultânea de antígenos internos e de superfície de Trypanosoma cruzi reativos para diferentes classes de imunoglobulinas (radio-immunoblotting

    Directory of Open Access Journals (Sweden)

    Anna Maria Simonsen Stolf

    1990-10-01

    Full Text Available A radioactive Western-blotting technique was developed by which the reactivity of Immunoglobulins (Igs from different classes to both membrane radiolabelled and internal parasite antigens is simultaneously identified. The method includes radioiodination of parasites, polypeptide fractionation by SDS-PAGE, Western-blot transfer and autoradiography of the immunoblots developed with anti-Igs conjugates labelled with enzymes. The analysis is then performed by the comparison of common bands on the autoradiograms and the respective substrate stained nitrocellulose blots. This technique was used to analyse T. cruzi trypomastigote surface labelled antigens reactive to IgM, IgA and IgG specific antibodies. A different pattern of reactivity with acute Chagas' disease patients sera was thus obtained.Classes e subclasses de anticorpos apresentam diferentes funções, influenciando a resposta imune humoral de um hospedeiro, frente a um agente infeccioso. Na maioria dos sistemas, o alvo principal é representado pelos antígenos de membrana do parasita. Entretanto, a identificação de antígenos de superfície de parasitas, reativos para classe (e subclasse de imunoglobulinas que não se ligam a proteína-A implica em imunoprecipitações sucessivas, que levam a perda de antígenos e/ou reações inespecíficas. Visando esse estudo, foi desenvolvida uma técnica denominada "radio-immunoblotting", através da qual a reatividade de imunoglobulinas de diferentes classes para antígenos de membrana (e/ou internos foi analisada simultaneamente. O método constitui na marcação prévia da superfície dos parasitas por radioiodação, fracionamento dos polipeptídeos por SDS/PA-GE, transferência das frações para nitrocelulose, reação com soros e conjugados anti-Igs - peroxidase e autoradiografia dos mesmos, a análise é feita comparando-se os antígenos comuns evidenciados na autoradiografia e nas tiras de nitrocelulose coradas com o substrato da peroxidase

  6. Detection of antibodies to variant antigens on Plasmodium falciparum-infected erythrocytes by flow cytometry

    DEFF Research Database (Denmark)

    Staalsoe, T; Giha, H A; Dodoo, D

    1999-01-01

    BACKGROUND: Naturally induced antibodies binding to surface antigens of Plasmodium falciparum-infected erythrocytes can be detected by direct agglutination of infected erythrocytes or by indirect immunofluorescence on intact, unfixed, infected erythrocytes. Agglutinating antibodies have previously...

  7. Blastogenic response of human lymphocytes to early antigen(s) of human cytomegalovirus.

    OpenAIRE

    Waner, J L; Kong, N; Biano, S

    1983-01-01

    The lymphocytes of asymptomatic, seropositive donors demonstrated blastogenic responses to early antigens of human cytomegalovirus whether or not antibodies to early antigens were detectable. The lymphocytes of six of nine patients with active cytomegalovirus infections gave stimulation indexes of greater than or equal to 2.00 with antigens of productively infected cells, whereas only two patients demonstrated comparable stimulation indexes with early antigens. Four patients with stimulation ...

  8. Antigenic cartography of H1N1 influenza viruses using sequence-based antigenic distance calculation.

    Science.gov (United States)

    Anderson, Christopher S; McCall, Patrick R; Stern, Harry A; Yang, Hongmei; Topham, David J

    2018-02-12

    The ease at which influenza virus sequence data can be used to estimate antigenic relationships between strains and the existence of databases containing sequence data for hundreds of thousands influenza strains make sequence-based antigenic distance estimates an attractive approach to researchers. Antigenic mismatch between circulating strains and vaccine strains results in significantly decreased vaccine effectiveness. Furthermore, antigenic relatedness between the vaccine strain and the strains an individual was originally primed with can affect the cross-reactivity of the antibody response. Thus, understanding the antigenic relationships between influenza viruses that have circulated is important to both vaccinologists and immunologists. Here we develop a method of mapping antigenic relationships between influenza virus stains using a sequence-based antigenic distance approach (SBM). We used a modified version of the p-all-epitope sequence-based antigenic distance calculation, which determines the antigenic relatedness between strains using influenza hemagglutinin (HA) genetic coding sequence data and provide experimental validation of the p-all-epitope calculation. We calculated the antigenic distance between 4838 H1N1 viruses isolated from infected humans between 1918 and 2016. We demonstrate, for the first time, that sequence-based antigenic distances of H1N1 Influenza viruses can be accurately represented in 2-dimenstional antigenic cartography using classic multidimensional scaling. Additionally, the model correctly predicted decreases in cross-reactive antibody levels with 87% accuracy and was highly reproducible with even when small numbers of sequences were used. This work provides a highly accurate and precise bioinformatics tool that can be used to assess immune risk as well as design optimized vaccination strategies. SBM accurately estimated the antigenic relationship between strains using HA sequence data. Antigenic maps of H1N1 virus strains reveal

  9. Purification of nonlipopolysaccharide antigen from Brucella abortus during preparation of antigen used for indirect hemolysis test.

    OpenAIRE

    Hoffmann, E M; Houle, J J

    1986-01-01

    The indirect hemolysis test (IHLT) for the diagnosis of brucellosis uses a lipopolysaccharide (LPS) antigen obtained by dimethyl sulfoxide extraction of Brucella abortus. We showed that a non-LPS antigen can be obtained as a by-product of the IHLT antigen preparation. The antigen was purified to homogeneity by a combination of gel-filtration chromatography and ion-exchange chromatography. The substance contained 8% protein and about 65% carbohydrate. The molecular weight of the primary unit w...

  10. Combination of cancer antigen 125 and carcinoembryonic antigen can improve ovarian cancer diagnosis

    DEFF Research Database (Denmark)

    Sørensen, Sofie Sølvsten; Mosgaard, Berit Jul

    2011-01-01

    The purpose of the present study was to evaluate the ability of the tumour marker carcinoembryonic antigen (CEA) in combination with cancer antigen 125 (CA-125) to differentiate between malignant ovarian and malignant non-ovarian disease.......The purpose of the present study was to evaluate the ability of the tumour marker carcinoembryonic antigen (CEA) in combination with cancer antigen 125 (CA-125) to differentiate between malignant ovarian and malignant non-ovarian disease....

  11. Benchtop Antigen Detection Technique using Nanofiltration and Fluorescent Dyes

    Science.gov (United States)

    Scardelletti, Maximilian C.; Varaljay, Vanessa

    2009-01-01

    The designed benchtop technique is primed to detect bacteria and viruses from antigenic surface marker proteins in solutions, initially water. This inclusive bio-immunoassay uniquely combines nanofiltration and near infrared (NIR) dyes conjugated to antibodies to isolate and distinguish microbial antigens, using laser excitation and spectrometric analysis. The project goals include detecting microorganisms aboard the International Space Station, space shuttle, Crew Exploration Vehicle (CEV), and human habitats on future Moon and Mars missions, ensuring astronaut safety. The technique is intended to improve and advance water contamination testing both commercially and environmentally as well. Lastly, this streamlined technique poses to greatly simplify and expedite testing of pathogens in complex matrices, such as blood, in hospital and laboratory clinics.

  12. A computational framework for influenza antigenic cartography.

    Science.gov (United States)

    Cai, Zhipeng; Zhang, Tong; Wan, Xiu-Feng

    2010-10-07

    Influenza viruses have been responsible for large losses of lives around the world and continue to present a great public health challenge. Antigenic characterization based on hemagglutination inhibition (HI) assay is one of the routine procedures for influenza vaccine strain selection. However, HI assay is only a crude experiment reflecting the antigenic correlations among testing antigens (viruses) and reference antisera (antibodies). Moreover, antigenic characterization is usually based on more than one HI dataset. The combination of multiple datasets results in an incomplete HI matrix with many unobserved entries. This paper proposes a new computational framework for constructing an influenza antigenic cartography from this incomplete matrix, which we refer to as Matrix Completion-Multidimensional Scaling (MC-MDS). In this approach, we first reconstruct the HI matrices with viruses and antibodies using low-rank matrix completion, and then generate the two-dimensional antigenic cartography using multidimensional scaling. Moreover, for influenza HI tables with herd immunity effect (such as those from Human influenza viruses), we propose a temporal model to reduce the inherent temporal bias of HI tables caused by herd immunity. By applying our method in HI datasets containing H3N2 influenza A viruses isolated from 1968 to 2003, we identified eleven clusters of antigenic variants, representing all major antigenic drift events in these 36 years. Our results showed that both the completed HI matrix and the antigenic cartography obtained via MC-MDS are useful in identifying influenza antigenic variants and thus can be used to facilitate influenza vaccine strain selection. The webserver is available at http://sysbio.cvm.msstate.edu/AntigenMap.

  13. Diagnostic Values of Carcinoembryonic Antigen, Cancer Antigen 15-3 and Cancer Antigen 125 Levels in Nipple Discharge.

    Science.gov (United States)

    Zhao, Song; Gai, Xiaodong; Wang, Yongmei; Liang, Weili; Gao, Haidong; Zhang, Kai; Wang, Huimin; Liu, Yanhong; Wang, Jianli; Ma, Rong

    2015-12-31

    An expedient and cost-effective diagnostic tool is needed to complement galactography and exfoliative cytology for detection of benign or malignant breast diseases with nipple discharge. The aim of this prospective study is to explore the utility of carcinoembryonic antigen, cancer antigen 15-3 and cancer antigen 125 levels in nipple discharge for the diagnosis of various breast diseases. We evaluated the pre-operative tumor marker levels in 153 nipple discharge samples collected from one or both breasts of 142 women undergoing surgery. Patients with nipple discharge underwent auxiliary examination (ultrasonography, exfoliative cytology, ductoscopy and galactography). Statistically higher levels of carcinoembryonic antigen and cancer antigen 15-3 were found in patients in the malignant group as compared to those in the benign group. No statistically significant difference in the level of cancer antigen 125 (P = 0.895). Sensitivities of carcinoembryonic antigen and cancer antigen 15-3 for diagnosing breast cancer were 74.42% and 58.14%, and specificities were 87.27% and 80.00% where as the cutoff values with max-sum of sensitivity and specificity were 224.3 ng/ml and 1368.2 U/ml, respectively. The following sensitivities for telling malignant from benign could be determined: exfoliative cytology 46.67%, ultrasonography 76.74%, galactography 75.00%, and ductoscopy 0%. Exfoliative cytology was found to be a valuable alternative method for differentiating benign from malignancy. Thus, tumor marker analysis of nipple discharge fluid for carcinoembryonic antigen and cancer antigen 15-3 would enhance the accurate assessment and treatment planning for patients with nipple discharge.

  14. Prostate-Specific Antigen (PSA) Test

    Science.gov (United States)

    ... antigen level New England Journal of Medicine 2004;350(22):2239-2246. [PubMed Abstract] Barry ... antigen testing for early diagnosis of prostate cancer. New England Journal of Medicine 2001;344(18):1373-1377. [PubMed Abstract] Pinsky ...

  15. Evaluation of an Antigen-Antibody

    African Journals Online (AJOL)

    GB

    1. ABSTRACT. BACKGROUND: Development of “combination” assays detecting in parallel, within a single test,. Hepatitis C Virus (HCV) antigens and antibodies, not ... considered above threshold of detection for antigen proteins suggested a lack of sensitivity by this assay ..... Hepatic veno-occlusive disease (sinusoidal.

  16. Vaccination and antigenic drift in influenza.

    Science.gov (United States)

    Boni, Maciej F

    2008-07-18

    The relationship between influenza antigenic drift and vaccination lies at the intersection of evolutionary biology and public health, and it must be viewed and analyzed in both contexts simultaneously. In this paper, 1 review what is known about the effects of antigenic drift on vaccination and the effects of vaccination on antigenic drift, and I suggest some simple ways to detect the presence of antigenic drift in seasonal influenza data. If antigenic drift occurs on the time scale of a single influenza season, it may be associated with the presence of herd immunity at the beginning of the season and may indicate a need to monitor for vaccine updates at the end of the season. The relationship between antigenic drift and vaccination must also be viewed in the context of the global circulation of influenza strains and the seeding of local and regional epidemics. In the data sets I consider--from New Zealand, New York, and France--antigenic drift can be statistically detected during some seasons, and seeding of epidemics appears to be endogenous sometimes and exogenous at other times. Improved detection of short-term antigenic drift and epidemic seeding would significantly benefit influenza monitoring efforts and vaccine selection.

  17. Conjugating influenza a (H1N1) antigen to n-trimethylaminoethylmethacrylate chitosan nanoparticles improves the immunogenicity of the antigen after nasal administration.

    Science.gov (United States)

    Liu, Qingfeng; Zheng, Xiaoyao; Zhang, Chi; Shao, Xiayan; Zhang, Xi; Zhang, Qizhi; Jiang, Xinguo

    2015-11-01

    As one of the most serious infectious respiratory diseases, influenza A (H1N1) is a great threat to human health, and it has created an urgent demand for effective vaccines. Nasal immunization can induce both systemic and mucosal immune responses against viruses, and it can serve as an ideal route for vaccination. However, the low immunogenicity of antigens on nasal mucosa is a high barrier for the development of nasal vaccines. In this study, we covalently conjugated an influenza A (H1N1) antigen to the surface of N-trimethylaminoethylmethacrylate chitosan (TMC) nanoparticles (H1N1-TMC/NP) through thioester bonds to increase the immunogenicity of the antigen after nasal administration. SDS-PAGE revealed that most of the antigen was conjugated on TMC nanoparticles, and an in vitro biological activity assay confirmed the stability of the antigen after conjugation. After three nasal immunizations, the H1N1-TMC/NP induced significantly higher levels of serum IgG and mucosal sIgA compared with free antigen. A hemagglutination inhibition assay showed that H1N1-TMC/NP induced much more protective antibodies than antigen-encapsulated nanoparticles or alum-precipitated antigen (I.M.). In the mechanistic study, H1N1-TMC/NP was shown to stimulate macrophages to produce IL-1β and IL-6 and to stimulate spleen lymphocytes to produce IL-2 and IFN-γ. These results indicated that H1N1-TMC/NP may be an effective vaccine against influenza A (H1N1) viruses for use in nasal immunization. © 2015 Wiley Periodicals, Inc.

  18. [Blood groups - minuses and pluses. Do the blood group antigens protect us from infectious diseases?].

    Science.gov (United States)

    Czerwiński, Marcin

    2015-06-25

    Human blood can be divided into groups, which is a method of blood classification based on the presence or absence of inherited erythrocyte surface antigens that can elicit immune response. According to the International Society of Blood Transfusion, there are 341 blood group antigens collected in 35 blood group systems. These antigens can be proteins, glycoproteins or glycosphingolipids, and function as transmembrane transporters, ion channels, adhesion molecules or receptors for other proteins. The majority of blood group antigens is present also on another types of cells. Due to their localization on the surface of cells, blood group antigens can act as receptors for various pathogens or their toxins, such as protozoa (malaria parasites), bacteria (Helicobacter pylori, Vibrio cholerae and Shigella dysenteriae) and viruses (Noroviruses, Parvoviruses, HIV). If the presence of group antigen (or its variant which arised due to mutation) is beneficial for the host (e.g. because pathogens are not able to bind to the cells), the blood group may become a selection trait, leading to its dissemination in the population exposed to that pathogen. There are thirteen blood group systems that can be related to pathogen resistance, and it seems that the particular influence was elicit by malaria parasites. It is generally thought that the high incidence of blood groups such as O in the Amazon region, Fy(a-b-) in Africa and Ge(-) in Papua-New Guinea is the result of selective pressure from malaria parasite. This review summarizes the data about relationship between blood groups and resistance to pathogens.

  19. Erythrocyte Membrane Antigen Frequencies in Patients with Type II Congenital Smell Loss

    Science.gov (United States)

    Stateman, William A.; Henkin, Robert I.; Knöppel, Alexandra; Flegel, Willy A.

    2014-01-01

    OBJECTIVE The objective of this study was to determine whether there are genetic factors associated with Type II congenital smell loss. STUDY DESIGN The expression frequencies of 16 erythrocyte antigens among patients with Type II congenital smell loss were determined and compared to those of a large control group. METHODS Blood samples were obtained from 99 patients with Type II congenital smell loss. Presence of the erythrocyte surface antigens A, B, M, N, S, s, Fya, Fyb, D, C, c, E, e, K, Jka, and Jkb was analyzed by blood group serology. Comparisons of expression frequencies of these antigens were made between the patients and a large control group. RESULTS Patients tested for the Duffy b antigen (Fyb haplotype) exhibited a statistically significant 11% decrease in expression frequency compared to the controls. There were no significant differences between patients and controls in the expression frequencies for all other erythrocyte antigens (A, B, M, N, S, s, Fya, D, C, c, E, e, K, Jka, or Jkb). CONCLUSIONS These findings describe the presence of a previously unrevealed genetic tendency among patients with Type II congenital smell loss related to erythrocyte surface antigen expression. The deviation in expression rate of Duffy b suggests a target gene and chromosome region in which future research into this form of congenital smell loss may reveal a more specific genetic basis for Type II congenital smell loss. PMID:25456515

  20. Participation of CD1 molecules in the presentation of bacterial protein antigens in humans.

    Science.gov (United States)

    Ulanova, M; Tarkowski, A; Hahn-Zoric, M; Hanson, L A

    1999-10-01

    Human CD1 molecules, expressed on the surface of professional antigen-presenting cells (including dendritic cells, Langerhans' cells, B cells and activated monocytes) are structurally homologous to major histocompatibility complex (MHC) class I and class II molecules. CD1b and CD1c have been shown to present nonpeptide bacterial antigens to T cells. We hypothesized that CD1 molecules may also be involved in the presentation of bacterial protein antigens. Human peripheral blood mononuclear cells (PBMC) were exposed to two medically important proteins, tetanus toxoid (TT) and purified protein derivative (PPD), with and without murine monoclonal antibodies (MoAbs) specific for CD1a, CD1b and CD1c. All the MoAbs substantially inhibited the proliferative responses of PBMC to TT and PPD. Simultaneous interaction of CD1 and MHC class II molecules was even more inhibitory to these antigen-specific proliferative responses. In contrast, neither mixed lymphocyte reaction nor superantigen and mitogenic responses were affected by CD1-specific antibodies, indicating a certain restriction pattern in antigen presentation. Our findings suggest that, besides MHC class I and II molecules, there is a family of nonpolymorphic cell surface molecules that is able to present certain bacterial protein antigens to T cells.

  1. Preserved MHC class II antigen processing in monocytes from HIV-infected individuals.

    Directory of Open Access Journals (Sweden)

    Laila Woc-Colburn

    2010-03-01

    Full Text Available MHC-II restricted CD4+ T cells are dependent on antigen presenting cells (APC for their activation. APC dysfunction in HIV-infected individuals could accelerate or exacerbate CD4+ T cell dysfunction and may contribute to increased levels of immunodeficiency seen in some patients regardless of their CD4+ T cell numbers. Here we test the hypothesis that APC from HIV-infected individuals have diminished antigen processing and presentation capacity.Monocytes (MN were purified by immuno-magnetic bead isolation techniques from HLA-DR1.01+ or DR15.01+ HIV-infected and uninfected individuals. MN were analyzed for surface MHC-II expression and for antigen processing and presentation capacity after overnight incubation with soluble antigen or peptide and HLA-DR matched T cell hybridomas. Surface expression of HLA-DR was 20% reduced (p<0.03 on MN from HIV-infected individuals. In spite of this, there was no significant difference in antigen processing and presentation by MN from 14 HIV-infected donors (8 HLA-DR1.01+ and 6 HLA-DR15.01+ compared to 24 HIV-uninfected HLA-matched subjects.We demonstrated that MHC class II antigen processing and presentation is preserved in MN from HIV-infected individuals. This further supports the concept that this aspect of APC function does not further contribute to CD4+ T cell dysfunction in HIV disease.

  2. Protein antigen delivery by gene gun-mediated epidermal antigen incorporation (EAI).

    Science.gov (United States)

    Scheiblhofer, Sandra; Ritter, Uwe; Thalhamer, Josef; Weiss, Richard

    2013-01-01

    The gene gun technology can not only be employed for efficient transfer of gene vaccines into upper layers of the skin, but also for application of protein antigens. As a tissue rich in professional antigen presenting cells, the skin represents an attractive target for immunizations. In this chapter we present a method for delivery of the model antigen ovalbumin into the skin of mice termed epidermal antigen incorporation and describe in detail how antigen-specific proliferation in draining lymph nodes can be followed by flow cytometry.

  3. Flow Cytometric Analysis of T, B, and NK Cells Antigens in Patients with Mycosis Fungoides

    Directory of Open Access Journals (Sweden)

    Serkan Yazıcı

    2015-01-01

    Full Text Available We retrospectively analyzed the clinicopathological correlation and prognostic value of cell surface antigens expressed by peripheral blood mononuclear cells in patients with mycosis fungoides (MF. 121 consecutive MF patients were included in this study. All patients had peripheral blood flow cytometry as part of their first visit. TNMB and histopathological staging of the cases were retrospectively performed in accordance with International Society for Cutaneous Lymphomas/European Organization of Research and Treatment of Cancer (ISCL/EORTC criteria at the time of flow cytometry sampling. To determine prognostic value of cell surface antigens, cases were divided into two groups as stable and progressive disease. 17 flow cytometric analyses of 17 parapsoriasis (PP and 11 analyses of 11 benign erythrodermic patients were included as control groups. Fluorescent labeled monoclonal antibodies were used to detect cell surface antigens: T cells (CD3+, CD4+, CD8+, TCRαβ+, TCRγδ+, CD7+, CD4+CD7+, CD4+CD7−, and CD71+, B cells (HLA-DR+, CD19+, and HLA-DR+CD19+, NKT cells (CD3+CD16+CD56+, and NK cells (CD3−CD16+CD56+. The mean value of all cell surface antigens was not statistically significant between parapsoriasis and MF groups. Along with an increase in cases of MF stage statistically significant difference was found between the mean values of cell surface antigens. Flow cytometric analysis of peripheral blood cell surface antigens in patients with mycosis fungoides may contribute to predicting disease stage and progression.

  4. sero-prevalence of hepatitis b surface antigen (hbsag)

    African Journals Online (AJOL)

    DR. AMINU

    of drugs, alcoholism, chemicals and environmental ... blood, serum, vaginal secretions and in saliva though in low concentrations (Lindsley et al., 1990). Although surrounded by a host cell derived envelope, HBV is remarkably stable to organic solvents. It is also heat and pH – resistant (Holling et al., 1995). Young children ...

  5. Prevalence of Hepatitis B surface antigen among pregnant women ...

    African Journals Online (AJOL)

    In developing countries there is no routine screening of hepatitis B virus (HBV) infection among pregnant women resulting into limited data on its magnitude. The objective of this study was to determine the prevalence and risk factors associated with active HBV infection among pregnant women attending antenatal clinic ...

  6. Seroprevalence of hepatitis B Surface antigen among apparently ...

    African Journals Online (AJOL)

    Introduction: Hepatitis B virus infection is a major public health problem worldwide. It is more infectious and more in Nigeria than the Human Immunodeficiency Virus (HIV). It is a major risk factor for the development of liver cirrhosis and hepatocellular cancer in hyperendemic areas. This study was carried out between 8th ...

  7. Sero-prevalence of hepatitis B surface antigen among primary ...

    African Journals Online (AJOL)

    hepatitis B virus (HBV) carriers. The prevalence of chronic HBV infection shows wide regional variation; ranging from high rates of greater than 8%, found in,. Africa, Asia and the Western Pacific to intermediate rates of 2-7% in Southern and Eastern Europe to low rates of less than 2%, in Western Europe, North America and.

  8. Hepatitis B Viral Markers in Surface Antigen Negative Blood Donors

    African Journals Online (AJOL)

    user1

    lymphoma and HIV positive patients,. Koo et al22 found 3.2% of lymphoma patients with positive anti-HBs to have detectable HBV DNA in their serum. Awerkiew et al12 and Wu et al14 have also reported the case of anti-HBs positive but negative for anti-HBc lymphoma patient who had reactivation of occult HBV infection on ...

  9. Prevalence of hepatitis B surface antigen sero-positivity and

    African Journals Online (AJOL)

    2016-07-31

    Jul 31, 2016 ... study and was carried out at the blood bank of the teaching hospital, Aba, from June 2013 and December 2014. Five hundred and thirty consecutively recruited voluntary blood donors were screened for hepatitis B and hepatitis C virus infections. Hepatitis B virus infection was screened using hepatitis B ...

  10. Detection of antibodies to Helicobacter pylori cell surface antigens.

    Science.gov (United States)

    Guruge, J L; Schalén, C; Nilsson, I; Ljungh, A; Tyszkiewicz, T; Wikander, M; Wadström, T

    1990-01-01

    Serum IgG antibodies of Helicobacter pylori were detected in single-dilution ELISA using glycine extracted material. Among 148 endoscopy patients 59% displayed antibodies; as expected, a higher occurrence (90%) was found in patients with positive gastric culture for H. pylori than in culture negative patients (37%). Among 68 blood donors the frequency of H. pylori antibodies was 28%. In 73 children less than 15 years of age examined for unrelated disorders the occurrence was 4%. By immunoblotting using the same extract, 3 prominent bands, 29K, 54K and 60K and several weak bands were identified. These were formed by 57%, 92%, and 65%, respectively, of the ELISA positive patient sera. Comparing culture positive and negative patients, the 3 bands occurred more often among the culture positive subjects though between 18 and 61% of the sera from culture negative patients gave either of the bands. When comparing the glycine extracts of 4 different H. pylori strains with separate haemagglutinating patterns no differences in the position of the major bands emerged. By absorption experiments no immunological cross-reactivity with components of Escherichia coli, Klebsiella pneumoniae, Campylobacter jejuni or C. fetus was found. Thus, the glycine extract seemed specific for the detection of antibodies to H. pylori.

  11. Seroprevalence of Hepatitis B Surface Antigen (HBsAg) among ...

    African Journals Online (AJOL)

    Globally, Hepatitis B Virus has been identified as one of the most common infectious diseases and a major public health problem.This study was therefore carried out to assess the prevalence of Hepatitis B virus infection among primary school children attending LGE primary school, Sabon Pegi, Kuru, Nigeria.

  12. Hepatitis B Viral Markers in Surface Antigen Negative Blood Donors ...

    African Journals Online (AJOL)

    Of the 20 who were anti-HBc positive, seven had tattoo/traditional marks on their body and one had previous history of blood transfusion. Conclusion: This study has shown that some potential blood units containing HBV are being transfused to patients unknowingly by screening for HBsAg only. Screening for other markers ...

  13. The Prevalence Of Hepatitis B Surface Antigen And Human ...

    African Journals Online (AJOL)

    Aims: To determine the prevalence of Human Immunodeficiency Virus (HIV) and Hepatitis B Virus (HBV) infection among persons with sickle cell anaemia. Methods: Serum samples of 47 non- transfused persons with sickle cell anaemia (controls) and 73 transfused (subjects) were sreened for HIV antibody or the Hepatitis B ...

  14. Prevalence of hepatitis B surface antigen, hepatitis C and Human ...

    African Journals Online (AJOL)

    Objective: Human immunodeficiency virus (HIV), hepatitis B virus, and hepatitis C viruses (HCV) are major causes of mortality and morbidity worldwide. They are also among the commonest transfusiontransmissible infectious agents. Students of higher institutions are often used as voluntary unpaid donors by many ...

  15. Prevalence of Hepatitis B surface antigen sero-positivity and ...

    African Journals Online (AJOL)

    Hepatitis B and C viruses are among the common infectious diseases of the world and constitute a major global health burden. Consequent upon their mode of transmission, thorough screening of blood has become absolutely necessary, making quick provision of safe blood rather difficult. This study aims at determining ...

  16. The value of serum Hepatitis B surface antigen quantification in ...

    African Journals Online (AJOL)

    HBe status, HBV DNA concentrations and serum ALT levels, based on the European Association for the study of the liver (EASL) guidelines.Serum HBsAg titres were measured using the Elecsys HBsAg II Quant assay (Roche Diagnostics).

  17. Hepatitis B surface antigen seropositivity and knowledge of Hepatitis ...

    African Journals Online (AJOL)

    Introduction: Despite its staggering toll on health, diseases arising from hepatitis are largely unknown, unappreciated, undiagnosed and untreated. Many Nigerians are unaware of their hepatitis B status and often present late to hospital with advanced chronic liver disease. The objectives were to determine the hepatitis B ...

  18. Cultural Influences on Hepatitis B Surface Antigen Seropositivity in ...

    African Journals Online (AJOL)

    Objective: To determine the role of cultural influences, namely: circumcision, ear piercing and traditional scarification, on HbsAg seropositivity among primary school children in Nnewi. Subjects and Method: Two hundred and thirty seven randomly selected primary school children aged 5-12 years, were screened for HbsAg.

  19. Monoclonal antibodies to antigens on human neutrophils, activated T lymphocytes, and acute leukemia blast cells

    International Nuclear Information System (INIS)

    Miterev, G.Yu.; Burova, G.F.; Puzhitskaya, M.S.; Danilevich, S.V.; Bulycheva, T.I.

    1987-01-01

    The authors describe the production of two mouse hybridomas secreting monoclonal antibodies to antigenic determinants of the surface membranes of human neutrophils, activated T lymphocytes, and acute leukemic blast cells. The degree of lymphocyte stimulation was estimated from incorporation of 3 H-thymidine with parallel microculture. Monoclonal antibodies of supernatants of hybridoma cultures shown here reacted in both immunofluorescence test and cytotoxicity test with surface membrane antigens on the majority of neutrophils and PHA-activated peripheral blood lymphocytes from healthy subjects, but did not give positive reactions with unactivated lymphocytes, adherent monocytes, erythrocytes, and alloantigen-stimulated lymphocytes

  20. Monoclonal antibodies to antigens on human neutrophils, activated T lymphocytes, and acute leukemia blast cells

    Energy Technology Data Exchange (ETDEWEB)

    Miterev, G.Yu.; Burova, G.F.; Puzhitskaya, M.S.; Danilevich, S.V.; Bulycheva, T.I.

    1987-11-01

    The authors describe the production of two mouse hybridomas secreting monoclonal antibodies to antigenic determinants of the surface membranes of human neutrophils, activated T lymphocytes, and acute leukemic blast cells. The degree of lymphocyte stimulation was estimated from incorporation of /sup 3/H-thymidine with parallel microculture. Monoclonal antibodies of supernatants of hybridoma cultures shown here reacted in both immunofluorescence test and cytotoxicity test with surface membrane antigens on the majority of neutrophils and PHA-activated peripheral blood lymphocytes from healthy subjects, but did not give positive reactions with unactivated lymphocytes, adherent monocytes, erythrocytes, and alloantigen-stimulated lymphocytes.

  1. Study of the antigenic cross reactivity between carcinoembryonic antigen and "nonspecific cross reacting antigens" (NCA and NCA 2).

    Science.gov (United States)

    Neveu, T.; Staebler, D.; Chavanel, G.; Burtin, P.

    1975-01-01

    The immunochemical relationship between CEA, NCA and NCA 2 was studied in guinea-pigs. Strong cross reactions were found between these antigens, either in delayed or anaphylactic reactions. Some specific determinants for each antigen could still be demonstrated. Delayed hypersensitivity is likely to be due to the protein moiety of the molecules while anaphylactic reactivity could probably be related to their glucidic parts. Consequently, CEA and NCA have common antigenic determinants on their glucidic and peptidic moieties, perhaps more on the latter ones. PMID:50854

  2. Antigenic variation: Molecular and genetic mechanisms of relapsing disease

    Energy Technology Data Exchange (ETDEWEB)

    Cruse, J.M.; Lewis, R.E.

    1987-01-01

    This book contains 10 chapters. They are: Contemporary Concepts of Antigenic Variation; Antigenic Variation in the Influenza Viruses; Mechanisms of Escape of Visna Lentiviruses from Immunological Control; A Review of Antigenic Variation by the Equine Infectious Anemia Virus; Biologic and Molecular Variations in AIDS Retrovirus Isolates; Rabies Virus Infection: Genetic Mutations and the Impact on Viral Pathogenicity and Immunity; Immunobiology of Relapsing Fever; Antigenic Variation in African Trypanosomes; Antigenic Variation and Antigenic Diversity in Malaria; and Mechanisms of Immune Evasion in Schistosomiasis.

  3. Mucosal delivery of antigens using adsorption to bacterial spores.

    Science.gov (United States)

    Huang, Jen-Min; Hong, Huynh A; Van Tong, Hoang; Hoang, Tran H; Brisson, Alain; Cutting, Simon M

    2010-01-22

    The development of new-generation vaccines has followed a number of strategic avenues including the use of live recombinant bacteria. Of these, the use of genetically engineered bacterial spores has been shown to offer promise as both a mucosal as well as a heat-stable vaccine delivery system. Spores of the genus Bacillus are currently in widespread use as probiotics enabling a case to be made for their safety. In this work we have discovered that the negatively charged and hydrophobic surface layer of spores provides a suitable platform for adsorption of protein antigens. Binding can be promoted under conditions of low pH and requires a potent combination of electrostatic and hydrophobic interactions between spore and immunogen. Using appropriately adsorbed spores we have shown that mice immunised mucosally can be protected against challenge with tetanus toxin, Clostridium perfringens alpha toxin and could survive challenge with anthrax toxin. In some cases protection is actually greater than using a recombinant vaccine. Remarkably, killed or inactivated spores appear equally effective as live spores. The spore appears to present a bound antigen in its native conformation promoting a cellular (T(h)1-biased) response coupled with a strong antibody response. Spores then, should be considered as mucosal adjuvants, most similar to particulate adjuvants, by enhancing responses against soluble antigens. The broad spectrum of immune responses elicited coupled with the attendant benefits of safety suggest that spore adsorption could be appropriate for improving the immunogenicity of some vaccines as well as the delivery of biotherapeutic molecules.

  4. Rabies virus glycoprotein as a carrier for anthrax protective antigen

    International Nuclear Information System (INIS)

    Live viral vectors expressing foreign antigens have shown great promise as vaccines against viral diseases. However, safety concerns remain a major problem regarding the use of even highly attenuated viral vectors. Using the rabies virus (RV) envelope protein as a carrier molecule, we show here that inactivated RV particles can be utilized to present Bacillus anthracis protective antigen (PA) domain-4 in the viral membrane. In addition to the RV glycoprotein (G) transmembrane and cytoplasmic domains, a portion of the RV G ectodomain was required to express the chimeric RV G anthrax PA on the cell surface. The novel antigen was also efficiently incorporated into RV virions. Mice immunized with the inactivated recombinant RV virions exhibited seroconversion against both RV G and anthrax PA, and a second inoculation greatly increased these responses. These data demonstrate that a viral envelope protein can carry a bacterial protein and that a viral carrier can display whole polypeptides compared to the limited epitope presentation of previous viral systems

  5. Correlation between expression of major histocompatibility complex class I and that of antigen presenting machineries in carcinoma cell lines of the pancreas, biliary tract and colon

    OpenAIRE

    Imanishi, Tatsuya; Kamigaki, Takashi; Nakamura, Tetsu; Hayashi, Shun; Yasuda, Takashi; Kawasaki, Kentaro; Takase, Shiro; Ajiki, Tetsuo; Kuroda, Yoshikazu

    2006-01-01

    To elicit a tumor immune response, tumor antigens represented by majorhistocompatibility (MHC) class I complex on the cell surface is indispensable. Someinvestigators demonstrated that many cancer cells reduce expression ofβ2-microglobulin, a transporter of antigen presenting (TAP) or low molecular protein(LMP), due to the deletion mutant or point mutation. We investigated gene expressionlevels of antigen presenting machineries in 13 cell lines of the pancreas, biliary tractand colon cancer b...

  6. MHC class I endosomal and lysosomal trafficking coincides with exogenous antigen loading in dendritic cells.

    Directory of Open Access Journals (Sweden)

    Genc Basha

    Full Text Available BACKGROUND: Cross-presentation by dendritic cells (DCs is a crucial prerequisite for effective priming of cytotoxic T-cell responses against bacterial, viral and tumor antigens; however, this antigen presentation pathway remains poorly defined. METHODOLOGY/PRINCIPAL FINDINGS: In order to develop a comprehensive understanding of this process, we tested the hypothesis that the internalization of MHC class I molecules (MHC-I from the cell surface is directly involved in cross-presentation pathway and the loading of antigenic peptides. Here we provide the first examination of the internalization of MHC-I in DCs and we demonstrate that the cytoplasmic domain of MHC-I appears to act as an addressin domain to route MHC-I to both endosomal and lysosomal compartments of DCs, where it is demonstrated that loading of peptides derived from exogenously-derived proteins occurs. Furthermore, by chasing MHC-I from the cell surface of normal and transgenic DCs expressing mutant forms of MHC-I, we observe that a tyrosine-based endocytic trafficking motif is required for the constitutive internalization of MHC-I molecules from the cell surface into early endosomes and subsequently deep into lysosomal peptide-loading compartments. Finally, our data support the concept that multiple pathways of peptide loading of cross-presented antigens may exist depending on the chemical nature and size of the antigen requiring processing. CONCLUSIONS/SIGNIFICANCE: We conclude that DCs have 'hijacked' and adapted a common vacuolar/endocytic intracellular trafficking pathway to facilitate MHC I access to the endosomal and lysosomal compartments where antigen processing and loading and antigen cross-presentation takes place.

  7. Demonstration of Antigenic Identity Between Purified Equine Infectious Anemia Virus and an Antigen Extracted from Infected Horse Spleen

    Science.gov (United States)

    Nakajima, Hideo; Norcross, Neil L.; Coggins, Leroy

    1972-01-01

    Antigenic relationship between purified equine infectious anemia (EIA) virus and spleen-derived antigen from EIA-infected horses was examined by immunodiffusion. Identical antigenicity of these two antigens has been proven because precipitation lines formed between the two antigens and EIA antiserum connected with each other. The results indicate that the antigenic substance derived from infected spleen is a component of EIA virus. Images PMID:4629262

  8. Indirect haemagglutination reaction with Sarcocystis dispersa antigen.

    Science.gov (United States)

    Cerva, L; Cerná, Z

    1982-01-01

    A description is given of the preparation of antigen from Sarcocystis dispersa cystozoites and the procedure of the indirect haemagglutination test (IHA). The antibodies against this antigen were detected in experimentally infected mice from day 20 p.i. (1: 640). In the following weeks the antibody titres reached the value of 1: 40,960. The sera of pigs, sheep and horses spontaneously infected with other Sarcocystis species reacted with this antigen in low titres only. The bovine sera gave negative reactions even in cases when Sarcocystis cysts were present in the muscles of the examined animals. A possible application of IHA for the research and diagnostic purposes is discussed.

  9. A sub-population of circulating porcine gammadelta T cells can act as professional antigen presenting cells.

    Science.gov (United States)

    Takamatsu, H-H; Denyer, M S; Wileman, T E

    2002-09-10

    A sub-population of circulating porcine gammadelta T cells express cell surface antigens associated with antigen presenting cells (APCs), and are able to take up soluble antigen very effectively. Functional antigen presentation by gammadelta T cells to memory helper T cells was studied by inbred pig lymphocytes immunised with ovalbumin (OVA). After removing all conventional APCs from the peripheral blood of immunised pigs, the remaining lymphocytes still proliferated when stimulated with OVA. When gammadelta T cells were further depleted, OVA specific proliferation was abolished, but reconstitution with gammadelta T cells restored proliferation. The proliferation was blocked by monoclonal antibodies (mAb) against MHC class II or CD4, and by pre-treatment of gammadelta T cells with chloroquine. These results indicate that a sub-population of circulating porcine gammadelta T cells act as APCs and present antigen via MHC class II.

  10. Nanoporous gold as a solid support for protein immobilization and development of an electrochemical immunoassay for prostate specific antigen and carcinoembryonic antigen

    International Nuclear Information System (INIS)

    Pandey, B.; Stine, K.J.; Demchenko, A.V.

    2012-01-01

    Nanoporous gold (NPG) was utilized as a support for immobilizing alkaline phosphatase (ALP) conjugated to monoclonal antibodies against either prostate specific antigen (PSA) or carcinoembryonic antigen (CEA). The antibody-ALP conjugates were coupled to self-assembled monolayers of lipoic acid and used in direct kinetic assays. Using the enzyme substrate p-aminophenyl phosphate, the product p-aminophenol was detected by its oxidation near 0.1 V (vs. Ag|AgCl) using square wave voltammetry. The difference in peak current arising from oxidation of p-aminophenol before and after incubation with biomarker increased with biomarker concentration. The response to these two biomarkers was linear up to 10 ng mL -1 for CEA and up to 30 ng mL -1 for PSA. The effect of interference on the PSA assay was studied using bovine serum albumin (BSA) as a model albumin protein. The effect of interference from a serum matrix was examined for the PSA assay using newborn calf serum. A competitive version of the immunoassay using antigen immobilized onto the NPG surface was highly sensitive at lower antigen concentration. Estimates of the surface coverage of the antibody-ALP conjugates on the NPG surface are presented. (author)

  11. Tissue polypeptide antigen activity in cerebrospinal fluid

    DEFF Research Database (Denmark)

    Bach, F; Söletormos, Georg; Dombernowsky, P

    1991-01-01

    Tissue polypeptide antigen (TPpA) in the cerebrospinal fluid (CSF) was measured in 59 consecutive breast cancer patients with suspected central nervous system (CNS) metastases. Subsequently, we determined that 13 patients had parenchymal brain metastases, 10 had leptomeningeal carcinomatosis...

  12. HLA antigens in three populations of India.

    Science.gov (United States)

    Papiha, S S; Wentzel, J; Shah, K C; Roberts, D F

    1989-01-01

    In blood samples from a Hindu population of Uttar Pradesh (North India) and from two Muslim groups, one from Andhra Pradesh (South India) and the other from Gujurat (West India), frequencies of 38 HLA-A, -B and -C antigens were investigated. Eight antigens - A23, A25, A29, A32, Bw45, B21, Bw22 and Bw53 - were absent in the Hindu population, four different antigens - A29, Bw52, B14 and Bw42 - were absent in Hyderabad Muslims, two antigens - A31 and Bw45 - were lacking in Surat Muslims. The three populations showed considerable genetic heterogeneity. The genetic difference between the two Muslim groups was small, but the Hindu population showed pronounced differences from each of the Muslim groups.

  13. 9 CFR 113.407 - Pullorum antigen.

    Science.gov (United States)

    2010-01-01

    ... determined by a colorimetric method. (2) The phenol content for Pullorum Tube Antigen shall be 0.55 ±0.05 percent as determined by direct titration with a standardized bromide-bromate solution. (d) Sensitivity...

  14. Acanthocheilonema viteae: Vaccination of jirds with irradiation-attenuated stage-3 larvae and with exported larval antigens

    International Nuclear Information System (INIS)

    Lucius, R.; Textor, G.; Kern, A.; Kirsten, C.

    1991-01-01

    Jirds (Meriones unguiculatus) were immunized with irradiated (35 krad) stage-3 larvae (L3) of Acanthocheilonema viteae. The induced resistance against homologous challenge infection and the antibody response of the animals were studied. Immunization with 3, 2, or 1 dose of 50 irradiated L3 induced approximately 90% resistance. Immunization with a single dose of only 5 irradiated L3 resulted in 60.8% protection while immunization with a single dose of 25 L3 induced 94.1% protection. The protection induced with 3 doses of 50 irradiated L3 did not decrease significantly during a period of 6 months. Sera of a proportion, but not all resistant jirds, contained antibodies against the surface of vector derived L3 as defined by IFAT. No surface antigens of microfilariae or adult worms were recognized by the sera. Vaccinated animals had antibody responses against antigens in the inner organs of L3 and in the cuticle and reproductive organs of adult worms as shown by IFAT. Immunoblotting with SDS-PAGE-separated L3 antigens and L3-CSN revealed that all sera contained antibodies against two exported antigens of 205 and 68 kDa, and against a nonexported antigen of 18 kDa. The 205-kDa antigen easily degraded into fragments of 165, 140, 125, and 105 kDa which were recognized by resistant jird sera. Various antigens of adult worms, but relatively few antigens of microfilariae, were also recognized. To test the relevance of exported antigens of L3 to resistance, jirds were immunized with L3-CSN together with a mild adjuvant. This immunization induced 67.7% resistance against challenge infection and sera of the immunized animals recognized the 205- and 68-kDa antigens of L3

  15. Carcinoembryonic antigen in thyroid cancer

    International Nuclear Information System (INIS)

    Weissel, M.; Hoefer, R.

    1982-01-01

    In order to investigate the usefulness of determining the serum concentrations of carcinoembryonic antigen (CEA) as a specific tumor marker in thyroid cancer, CEA serum levels were measured (enzymeimmunoassay, Abbott-Kit) repeatedly at the routine followup checks performed at various intervals after total thyroidectomy, in 65 patients with papillary, 82 with follicular, 25 with mixed type (papillary/follicular), 8 with anaplastic, and in 18 patients with medullary thyroid cancer. The postoperative observation period of these patients ranged from 2 to 36 months. Calcitonin serum levels were additionally determined in patients with medullary carcinoma (radioimmunoassay kit of Immuno-Nuclear Corp.). In the family of one patient with medullary carcinoma we also had an opportunity to investigate, within the framework of family screening (pentagastrin tests, etc.), the value of preoperative CEA determination. In the patients with ''non-medullary'' histological types of thyroid cancer, the maximum CEA serum concentration was 9.8 ng/ml. 6% of the patients with papillary, 9% of the patients with follicular, and 8% of those with mixed type thyroid cancer had serum levels above the upper limit of our normal range (5 ng/ml). All patients with anaplastic carcinoma had values below 3 ng/ml. The values quoted represent maximal values and were confirmed at various follow-up checks. However, 1 year after thyroidectomy, a female patient with follicular thyroid carcinoma developed an adenocarcinoma of the rectum: The CEA levels measured in this patient were: 4.2 ng/ml 3 weeks after thyroidectomy, 8.4 ng/ml 6 months later, and 37 ng/ml 1 week before operation on the rectum. In none of the other patients with elevated CEA levels were metastases of thyroid cancer, or any other malignancy, detected. (orig.) [de

  16. Enhanced Direct Major Histocompatibility Complex Class I Self-Antigen Presentation Induced by Chlamydia Infection.

    Science.gov (United States)

    Cram, Erik D; Simmons, Ryan S; Palmer, Amy L; Hildebrand, William H; Rockey, Daniel D; Dolan, Brian P

    2016-02-01

    The direct major histocompatibility complex (MHC) class I antigen presentation pathway ensures intracellular peptides are displayed at the cellular surface for recognition of infected or transformed cells by CD8(+) cytotoxic T lymphocytes. Chlamydia spp. are obligate intracellular bacteria and, as such, should be targeted by CD8(+) T cells. It is likely that Chlamydia spp. have evolved mechanisms to avoid the CD8(+) killer T cell responses by interfering with MHC class I antigen presentation. Using a model system of self-peptide presentation which allows for posttranslational control of the model protein's stability, we tested the ability of various Chlamydia species to alter direct MHC class I antigen presentation. Infection of the JY lymphoblastoid cell line limited the accumulation of a model host protein and increased presentation of the model-protein-derived peptides. Enhanced self-peptide presentation was detected only when presentation was restricted to defective ribosomal products, or DRiPs, and total MHC class I levels remained unaltered. Skewed antigen presentation was dependent on a bacterial synthesized component, as evidenced by reversal of the observed phenotype upon preventing bacterial transcription, translation, and the inhibition of bacterial lipooligosaccharide synthesis. These data suggest that Chlamydia spp. have evolved to alter the host antigen presentation machinery to favor presentation of defective and rapidly degraded forms of self-antigen, possibly as a mechanism to diminish the presentation of peptides derived from bacterial proteins. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  17. Naturally Acquired Human Immunity to Pneumococcus Is Dependent on Antibody to Protein Antigens.

    Directory of Open Access Journals (Sweden)

    Robert Wilson

    2017-01-01

    Full Text Available Naturally acquired immunity against invasive pneumococcal disease (IPD is thought to be dependent on anti-capsular antibody. However nasopharyngeal colonisation by Streptococcus pneumoniae also induces antibody to protein antigens that could be protective. We have used human intravenous immunoglobulin preparation (IVIG, representing natural IgG responses to S. pneumoniae, to identify the classes of antigens that are functionally relevant for immunity to IPD. IgG in IVIG recognised capsular antigen and multiple S. pneumoniae protein antigens, with highly conserved patterns between different geographical sources of pooled human IgG. Incubation of S. pneumoniae in IVIG resulted in IgG binding to the bacteria, formation of bacterial aggregates, and enhanced phagocytosis even for unencapsulated S. pneumoniae strains, demonstrating the capsule was unlikely to be the dominant protective antigen. IgG binding to S. pneumoniae incubated in IVIG was reduced after partial chemical or genetic removal of bacterial surface proteins, and increased against a Streptococcus mitis strain expressing the S. pneumoniae protein PspC. In contrast, depletion of type-specific capsular antibody from IVIG did not affect IgG binding, opsonophagocytosis, or protection by passive vaccination against IPD in murine models. These results demonstrate that naturally acquired protection against IPD largely depends on antibody to protein antigens rather than the capsule.

  18. Fas antigen (CD95) expression and apoptosis in hepatocytes of patients with chronic viral hepatitis.

    Science.gov (United States)

    Kiyici, Murat; Gurel, Selim; Budak, Ferah; Dolar, Enver; Gulten, Macit; Nak, Selim Giray; Memik, Faruk

    2003-10-01

    Apoptosis may be defined as programmed cell death. It is involved in the normal development and homeostasis of tissues in multicellular organisms. An increased or decreased rate of apoptosis may lead to a range of diseases. Fas antigen is a cell-surface receptor that induces apoptotic pathways when treated with Fas ligand or anti-Fas antibody. There is increasing evidence that apoptosis plays an important role in the immunopathogenesis of chronic viral hepatitis, in which the Fas antigen-Fas ligand pathway is particularly involved. Fas antigen expression and apoptosis (apoptotic index) were assayed using flow cytometry in the hepatocytes of 27 patients with chronic viral hepatitis. Histopathological activity, scored by Knodell's histological activity index, other histopathological parameters, serum transaminase values and patient age were then compared with apoptotic index and Fas antigen expression. Apoptosis and Fas antigen expression in hepatocytes were correlated closely with histological activity (grade) of chronic viral hepatitis, but there were no correlations with histological stage, patient age or serum transaminase levels. Apoptosis and its triggering molecule, Fas antigen, induce mechanisms that appear to be associated with the pathogenesis of chronic viral hepatitis.

  19. Antigenic variation in vector-borne pathogens.

    OpenAIRE

    Barbour, A. G.; Restrepo, B. I.

    2000-01-01

    Several pathogens of humans and domestic animals depend on hematophagous arthropods to transmit them from one vertebrate reservoir host to another and maintain them in an environment. These pathogens use antigenic variation to prolong their circulation in the blood and thus increase the likelihood of transmission. By convergent evolution, bacterial and protozoal vector-borne pathogens have acquired similar genetic mechanisms for successful antigenic variation. Borrelia spp. and Anaplasma marg...

  20. Allosensibilisation to erythrocyte antigens (literature review

    Directory of Open Access Journals (Sweden)

    N. V. Mineeva

    2015-01-01

    Full Text Available In this article literature review of the causes of allosensibilisation to erythrocyte antigens are presented. It is shown that the ability to produce antierythrocyte antibodies is affected by many factors, principal of whom it is difficult to identify. For the allosensibilisation development requires genetically determined differences in erythrocyte antigens phenotypes of donor and recipient, mother and fetus, which can lead to immune response and antibodies production. The biochemical nature of erythrocyte antigens, antigen dose (the amount of transfused doses, the number of antigens determinants on donor and fetus erythrocytes, the number of pregnancies are important. Individual patient characteristics: age, gender, diseases, the use of immunosuppressive therapy and the presence of inflammatory processes, are also relevant. Note that antibody to one erythrocyte antigens have clinical value, and to the other – have no. The actual data about frequency of clinically significant antibodies contribute to the development of post-transfusion hemolytic complications prophylaxis as well as the improvement of laboratory diagnosis of hemolytic disease of the newborn in the presence of maternal antierythrocyte antibodies.

  1. [Antigenic relations of several strains of Naegleria].

    Science.gov (United States)

    Zubiaur, E; Alonso, P

    1987-02-01

    In previous papers different aspects of one strain of Naegleria lovaniensis (Aq/9/1/45D) and two strains of N. gruberi (1518/le and 1518/lf) have been studied. From the results obtained it can be concluded that each strain behaves differently; no more similarities have been found between both N. gruberi strains, than between each of these and N. lovaniensis. Such an event has prompted us to characterize their antigenic relationships by means of an immunoprecipitation assay (double diffusion in plate). Each antiserum was tested against the different antigenic extracts. For N. lovaniensis, besides the whole extract, two fractions (particulate and soluble) and their respective antisera were assayed separately. No reaction occurred between any of the anti-N. lovaniensis sera and either of the two N. gruberi extracts. The antiserum to N. gruberi 1518/lf reacted only with its homologue and with N. lovaniensis antigens. Both N. lovaniensis fractions share some antigenic components being more complex the antigenic structure of the soluble fraction. Therefore no more similarities occur between both N. gruberi strains than between each one and N. lovaniensis, rather N. gruberi 1518/le exhibits more antigenic relationships with N. lovaniensis than with 1518/lf strains. In view of such results the species N. gruberi should be taxonomically reconsidered, criterium shared by other authors.

  2. Identification and localization of a soluble antigen, Ag2, of 136 kDa from Plasmodium falciparum in vitro cultures

    DEFF Research Database (Denmark)

    Jakobsen, P H; Grellier, P; Theander, T G

    1991-01-01

    as a duplet with molecular masses of 136 and 120 kDa when tested by immunoblotting. Immunoprecipitation experiments on Triton X-100 extracted antigens from synchronized cultures showed that the antigen was synthesized in the schizont stage. Ag2 was located near the surface of schizonts in the parasitophorous...

  3. The structure and significance of enterobacterial common antigen (ECA

    Directory of Open Access Journals (Sweden)

    Tomasz Kasper Goździewicz

    2015-09-01

    Full Text Available The enterobacterial common antigen (ECA is a carbohydrate-derived cell surface antigen present in all Gram-negative bacteria belonging to Enterobacteriaceae family. Biosynthetic pathways shared by ECA and LPS (endotoxin suggest close connections between these antigens. ECA occurs in three different forms: a phosphatidyl-linked linear polysaccharide anchored on the cell surface (ECAPG, a cyclic form built of 4-6 repeating units localized in the periplasm (ECACYC and as a linear polysaccharide covalently linked to LPS core oligosaccharide (ECALPS. Regardless of ECA form, poly- and oligosaccharides of ECA consist of the biological trisaccharide repeating units: →3-α-d-Fucp4NAc-(1→4-β-d-ManpNAcA-(1→4-α-d-GlcpNAc-(1→, where Fucp4NAc refers to 4-acetamido-2,4-dideoxygalactose, ManpNAcA to N-acetyl-mannosaminuronic acid and GlcpNAc to N-acetylglucosamine. ECAPG and ECALPS consisting of one unit with Fucp4NAc as a terminal sugar were also identified. The number of the studies shows its occurrence in all members of enteric bacteria with a few exceptions such as Erwinia chrysanthemi. The presence of ECA was also shown for such genera as Plesiomonas [4] and Yersinia [36], previously belonging to the Vibrionaceae and Pasteurellaceae families, respectively. It was one of the reasons to include these two taxa in the Enterobacteriaceae family. The function of ECA is not fully understood, but it was reported that its occurrence is important in resistance of bacterial cells to environmental conditions, such as bile salts in the human digestive tract. The immunogenicity of ECA seems very interesting in the fact that only sparse rough Gram-negative strains, such as Shigella sonnei phase II, Escherichia coli R1, R2, R4, K-12, and Yersinia enterocolitica O:3 are able to induce the production of specific anti-ECA antibodies. It is the effect of the ECALPS, and the evidence for the existence of such covalent linkage was provided by structural analysis of S

  4. CHARACTERIZATION OF THE CARBOHYDRATE COMPONENTS OF Taenia solium ONCOSPHERE PROTEINS AND THEIR ROLE IN THE ANTIGENICITY

    Science.gov (United States)

    Arana, Yanina; Verastegui, Manuela; Tuero, Iskra; Grandjean, Louis; Garcia, Hector H.; Gilman, Robert H.

    2015-01-01

    This study examines the carbohydrate composition of Taenia solium whole oncosphere antigens (WOAs), in order to improve the understanding of the antigenicity of the T. solium. Better knowledge of oncosphere antigens is crucial to accurately diagnose previous exposure to T. solium eggs and thus predict the development of neurocysticercosis. A set of seven lectins conjugates with wide carbohydrate specificity were used on parasite fixations and somatic extracts. Lectin fluorescence revealed that D-mannose, D-glucose, D-galactose and N-acetyl-D-galactosamine residues were the most abundant constituents of carbohydrate chains on the surface of T. solium oncosphere. Lectin blotting showed that post-translational modification with N-glycosylation was abundant while little evidence of O-linked carbohydrates was observed. Chemical oxidation and enzymatic deglycosylation in situ were performed to investigate the immunoreactivity of the carbohydrate moieties. Linearizing or removing the carbohydrate moieties from the protein backbones did not diminish the immunoreactivity of these antigens, suggesting that a substantial part of the host immune response against T. solium oncosphere is directed against the peptide epitopes on the parasite antigens. Finally, using carbohydrate probes, we demonstrated for the first time that the presence of several lectins on the surface of the oncosphere was specific to carbohydrates found in intestinal mucus, suggesting a possible role in initial attachment of the parasite to host cells. PMID:23982308

  5. Flow Virometry to Analyze Antigenic Spectra of Virions and Extracellular Vesicles.

    Science.gov (United States)

    Arakelyan, Anush; Fitzgerald, Wendy; Zicari, Sonia; Vagida, Murad; Grivel, Jean-Charles; Margolis, Leonid

    2017-01-25

    Cells release small extracellular vesicles (EVs) into the surrounding media. Upon virus infection cells also release virions that have the same size of some of the EVs. Both virions and EVs carry proteins of the cells that generated them and are antigenically heterogeneous. In spite of their diversity, both viruses and EVs were characterized predominantly by bulk analysis. Here, we describe an original nanotechnology-based high throughput method that allows the characterization of antigens on individual small particles using regular flow cytometers. Viruses or extracellular vesicles were immunocaptured with 15 nm magnetic nanoparticles (MNPs) coupled to antibodies recognizing one of the surface antigens. The captured virions or vesicles were incubated with fluorescent antibodies against other surface antigens. The resultant complexes were separated on magnetic columns from unbound antibodies and analyzed with conventional flow cytometers triggered on fluorescence. This method has wide applications and can be used to characterize the antigenic composition of any viral- and non-viral small particles generated by cells in vivo and in vitro. Here, we provide examples of the usage of this method to evaluate the distribution of host cell markers on individual HIV-1 particles, to study the maturation of individual Dengue virions (DENV), and to investigate extracellular vesicles released into the bloodstream.

  6. Screening for epitope specificity directly on culture supernatants in the early phase of monoclonal antibody production by an ELISA with biotin-labeled antigen

    DEFF Research Database (Denmark)

    Andersen, Ditte C; Jensen, Charlotte H; Gregersen, Annemette

    2004-01-01

    This report describes an assay for comparison of epitope specificity in groups of monoclonal antibodies against a given antigen. The only prerequisite is the biotin-labeled antigen. One of the monoclonal antibodies is captured onto a plastic surface via a rabbit anti-mouse Ig, and the other...... preincubated with biotinylated antigen. When the two antibodies react with the same epitope subsequent binding of the biotin-labeled antigen is abolished (inhibition). In the cases where no inhibition was observed, the two antibodies were considered to react with distinct, independent epitopes. The obvious...

  7. Antigen-43-mediated autoaggregation of Escherichia coli is blocked by fimbriation

    DEFF Research Database (Denmark)

    Hasman, Henrik; Chakraborty, Trinad; Klemm, Per

    1999-01-01

    Antigen 43 (Ag43), the product of the flu gene, is a surface-displayed autotransporter protein of Escherichia coli. Ag43 is responsible for the autoaggregation and flocculation of static liquid cultures of many E. coli strains. The expression of Ag43 has been reported to be phase variable...

  8. VaxiJen: a server for prediction of protective antigens, tumour antigens and subunit vaccines

    Directory of Open Access Journals (Sweden)

    Flower Darren R

    2007-01-01

    Full Text Available Abstract Background Vaccine development in the post-genomic era often begins with the in silico screening of genome information, with the most probable protective antigens being predicted rather than requiring causative microorganisms to be grown. Despite the obvious advantages of this approach – such as speed and cost efficiency – its success remains dependent on the accuracy of antigen prediction. Most approaches use sequence alignment to identify antigens. This is problematic for several reasons. Some proteins lack obvious sequence similarity, although they may share similar structures and biological properties. The antigenicity of a sequence may be encoded in a subtle and recondite manner not amendable to direct identification by sequence alignment. The discovery of truly novel antigens will be frustrated by their lack of similarity to antigens of known provenance. To overcome the limitations of alignment-dependent methods, we propose a new alignment-free approach for antigen prediction, which is based on auto cross covariance (ACC transformation of protein sequences into uniform vectors of principal amino acid properties. Results Bacterial, viral and tumour protein datasets were used to derive models for prediction of whole protein antigenicity. Every set consisted of 100 known antigens and 100 non-antigens. The derived models were tested by internal leave-one-out cross-validation and external validation using test sets. An additional five training sets for each class of antigens were used to test the stability of the discrimination between antigens and non-antigens. The models performed well in both validations showing prediction accuracy of 70% to 89%. The models were implemented in a server, which we call VaxiJen. Conclusion VaxiJen is the first server for alignment-independent prediction of protective antigens. It was developed to allow antigen classification solely based on the physicochemical properties of proteins without

  9. Expression and Antigenic Evaluation of VacA Antigenic Fragment of Helicobacter Pylori

    Science.gov (United States)

    Hasanzadeh, Leila; Ghaznavi-Rad, Ehsanollah; Soufian, Safieh; Farjadi, Vahideh; Abtahi, Hamid

    2013-01-01

    Objective(s) : Helicobacter pylori, a human specific gastric pathogen is a causative agent of chronic active gastritis. The vacuolating cytotoxin (VacA) is an effective virulence factor involved in gastric injury. The aim of this study was to construct a recombinant protein containing antigenic region of VacA gene and determine its antigenicity. Materials and Methods: The antigenic region of VacA gene was detected by bioinformatics methods. The polymerase chain reaction method was used to amplify a highly antigenic region of VacA gene from chromosomal DNA of H. pylori. The eluted product was cloned into the prokaryotic expression vector pET32a. The target protein was expressed in the Escherichia coli BL21 (DE3) pLysS. The bacteria including pET32a-VacA plasmids were induced by IPTG. The antigenicity was finally studied by western blotting using sera of 15 H. pylori infected patients after purification. Results: Enzyme digestion analysis, PCR and DNA sequencing results showed that the target gene was inserted correctly into the recombinant vector. The expressed protein was purified successfully via affinity chromatography. Data indicated that antigenic region of VacA protein from Helicobacter pylori was recognized by all 15 patient’s sera. Conclusion : Our data showed that antigenic region of VacA protein can be expressed by in E. co.li. This protein was recognized by sera patients suffering from H. pylori infection. the recombinant protein has similar epitopes and close antigenic properties to the natural form of this antigen. Recombinant antigenic region of VacA protein also seems to be a promising antigen for protective and serologic diagnosis . PMID:23997913

  10. Expression and Antigenic Evaluation of VacA Antigenic Fragment of Helicobacter Pylori

    Directory of Open Access Journals (Sweden)

    Leila Hasanzadeh

    2013-07-01

    Full Text Available Objective(s: Helicobacter pylori, a human specific gastric pathogen is a causative agent of chronic active gastritis. The vacuolating cytotoxin (VacA is an effective virulence factor involved in gastric injury. The aim of this study was to construct a recombinant protein containing antigenic region of VacA gene and determine its antigenicity.   Materials and Methods: The antigenic region of VacA gene was detected by bioinformatics methods. The polymerase chain reaction method was used to amplify a highly antigenic region of VacA gene from chromosomal DNA of H. pylori. The eluted product was cloned into the prokaryotic expression vector pET32a. The target protein was expressed in the Escherichia coli BL21 (DE3 pLysS. The bacteria including pET32a-VacA plasmids were induced by IPTG. The antigenicity was finally studied by western blotting using sera of 15 H. pylori infected patients after purification. Results: Enzyme digestion analysis, PCR and DNA sequencing results showed that the target gene was inserted correctly into the recombinant vector. The expressed protein was purified successfully via affinity chromatography. Data indicated that antigenic region of VacA protein from Helicobacter pylori was recognized by all 15 patient’s sera. Conclusion : Our data showed that antigenic region of VacA protein can be expressed by in E. co.li. This protein was recognized by sera patients suffering from H. pylori infection. the recombinant protein has similar epitopes and close antigenic properties to the natural form of this antigen. Recombinant antigenic region of VacA protein also seems to be a promising antigen for protective and serologic diagnosis .

  11. Functional role of BK virus tumor antigens in transformation.

    OpenAIRE

    Nakshatri, H; Pater, M M; Pater, A

    1988-01-01

    We have examined the role of the human papovavirus BK virus (BKV) tumor (T) antigen(s) in the maintenance of transformation and have identified the domain of T antigen essential for transformation. BKV-transformed BHK 21 and NIH 3T3 cells expressing antisense T-antigen RNA lose their ability to grow in soft agar, indicating the need for the continued expression of T antigen for the maintenance of the transformed phenotype. Experiments using translation termination linker insertion and deletio...

  12. A novel recycling mechanism of native IgE-antigen complexes in human B cells facilitates transfer of antigen to dendritic cells for antigen presentation.

    Science.gov (United States)

    Engeroff, Paul; Fellmann, Marc; Yerly, Daniel; Bachmann, Martin F; Vogel, Monique

    2017-10-23

    IgE-immune complexes (IgE-ICs) have been shown to enhance antibody and T-cell responses in mice by targeting CD23 (FcεRII), the low-affinity receptor for IgE on B cells. In humans, the mechanism by which CD23-expressing cells take up IgE-ICs and process them is not well understood. To investigate this question, we compared the fate of IgE-ICs in human B cells and in CD23-expressing monocyte-derived dendritic cells (moDCs) that represent classical antigen-presenting cells and we aimed at studying IgE-dependent antigen presentation in both cell types. B cells and monocytes were isolated from peripheral blood, and monocytes were differentiated into moDCs. Both cell types were stimulated with IgE-ICs consisting of 4-hydroxy-3-iodo-5-nitrophenylacetyl (NIP)-specific IgE JW8 and NIP-BSA to assess binding, uptake, and degradation dynamics. To assess CD23-dependent T-cell proliferation, B cells and moDCs were pulsed with IgE-NIP-tetanus toxoid complexes and cocultured with autologous T cells. IgE-IC binding was CD23-dependent in B cells, and moDCs and CD23 aggregation, as well as IgE-IC internalization, occurred in both cell types. Although IgE-ICs were degraded in moDCs, B cells did not degrade the complexes but recycled them in native form to the cell surface, enabling IgE-IC uptake by moDCs in cocultures. The resulting proliferation of specific T cells was dependent on cell-cell contact between B cells and moDCs, which was explained by increased upregulation of costimulatory molecules CD86 and MHC class II on moDCs induced by B cells. Our findings argue for a novel model in which human B cells promote specific T-cell proliferation on IgE-IC encounter. On one hand, B cells act as carriers transferring antigen to more efficient antigen-presenting cells such as DCs. On the other hand, B cells can directly promote DC maturation and thereby enhance T-cell stimulation. Copyright © 2017. Published by Elsevier Inc.

  13. Antigenic determinant of the Lancefield group H antigen of Streptococcus sanguis.

    Science.gov (United States)

    Rosan, B; Argenbright, L

    1982-01-01

    Previous studies indicated that the teichoic acid isolated from strains of Streptococcus sanguis was group specific and defined the Lancefield group H streptococci. To determine the specific antigenic determinants, the antigen was extracted from a group H streptococcus (ATCC 903) by the phenol-water method and purified by column chromatography. The isolated antigen had a glycerol/phosphate/glucose molar ratio of 1:0.9:0.3; the lipid concentration was 7.6% of its dry weight. No nucleic acids were detected, and amino acids constituted approximately 2% of the dry weight. The minimum concentration of antigen required to sensitize erythrocytes for hemagglutination with a 1:1,000 dilution of either group H antiserum or antiteichoic acid serum was 0.02 microgram/ml. Hemagglutination inhibition studies suggested that the major antigenic determinant consisted of an alpha-glucose linked to the glycerol phosphate backbone. Images PMID:6185428

  14. A melanoma immune response signature including Human Leukocyte Antigen-E.

    Science.gov (United States)

    Tremante, Elisa; Ginebri, Agnese; Lo Monaco, Elisa; Benassi, Barbara; Frascione, Pasquale; Grammatico, Paola; Cappellacci, Sandra; Catricalà, Caterina; Arcelli, Diego; Natali, Pier Giorgio; Di Filippo, Franco; Mottolese, Marcella; Visca, Paolo; Benevolo, Maria; Giacomini, Patrizio

    2014-01-01

    Paired cultures of early-passage melanoma cells and melanocytes were established from metastatic lesions and the uninvolved skin of five patients. In this stringent autologous setting, cDNA profiling was used to analyze a subset of 1477 genes selected by the Gene Ontology term 'immune response'. Human Leukocyte Antigen E (HLA-E) was ranked 19th among melanoma-overexpressed genes and was embedded in a transformation signature including its preferred peptide ligand donors HLA-A, HLA-B, HLA-C, and HLA-G. Mostly undetectable in normal skin and 39 nevi (including rare and atypical lesions), HLA-E was detected by immunohistochemistry in 17/30 (57%) and 32/48 (67%) primary and metastatic lesions, respectively. Accordingly, surface HLA-E was higher on melanoma cells than on melanocytes and protected the former (6/6 cell lines) from lysis by natural killer (NK) cells, functionally counteracting co-expressed triggering ligands. Although lacking HLA-E, melanocytes (4/4 cultures) were nevertheless (and surprisingly) fully protected from NK cell lysis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. [Enterobacterial antigen in human peripheral blood lymphocytes].

    Science.gov (United States)

    Faure-Fontenla, M A; García-Tamayo, F

    1989-11-01

    The following study has as prior history the research reports which have shown the existence of an antigenic tissue deposit in gram-negative enterobacteria. The antigens of the enterobacteria have also been found in the lymphocytic membranes and cytoplasm. Since intestinal lymphoid tissue cells can recirculate by means of the thoracic duct to the peripheral venous system, it was proposed that the circulating lymphocytes in healthy people could also contain small amounts of a common enterobacterial antigen. The study was carried out in 15 human venous blood samples, of which the lymphocytic population was separated to later be used in the preparation of 15 alcohol soluble extracts. This material was used for inhibiting the immuno-hemolysis assay in three occasions in order to show the presence of antigens shared by different enterobacterias, using as reference a fraction separated from the LPS of Escherichia coli 08. The results showed that the human lymphocytes also had antigenic determinants common to gram-negative bacteria.

  16. Transgenic lettuce seedlings carrying hepatitis B virus antigen HBsAg

    Directory of Open Access Journals (Sweden)

    Jackson Marcondes

    Full Text Available The obtainment of transgenic edible plants carrying recombinant antigens is a desired issue in search for economic alternatives viewing vaccine production. Here we report a strategy for genetic transformation of lettuce plants (Lactuca sativa L. using the surface antigen HBsAg of hepatitis B virus. Transgenic lettuce seedlings were obtained through the application of a regulated balance of plant growth regulators. Genetic transformation process was acquired by cocultivation of cotyledons with Agrobacterium tumefaciens harboring the recombinant plasmid. It is the first description of a lettuce Brazilian variety "Vitória de Verão" genetically modified.

  17. Transgenic lettuce seedlings carrying hepatitis B virus antigen HBsAg.

    Science.gov (United States)

    Marcondes, Jackson; Hansen, Ekkehard

    2008-12-01

    The obtainment of transgenic edible plants carrying recombinant antigens is a desired issue in search for economic alternatives viewing vaccine production. Here we report a strategy for genetic transformation of lettuce plants (Lactuca sativa L.) using the surface antigen HBsAg of hepatitis B virus. Transgenic lettuce seedlings were obtained through the application of a regulated balance of plant growth regulators. Genetic transformation process was acquired by cocultivation of cotyledons with Agrobacterium tumefaciens harboring the recombinant plasmid. It is the first description of a lettuce Brazilian variety 'Vitória de Verão' genetically modified.

  18. Flow cytometric assay detecting cytotoxicity against human endogenous retrovirus antigens expressed on cultured multiple sclerosis cells

    DEFF Research Database (Denmark)

    Møller-Larsen, A; Brudek, T; Petersen, T

    2013-01-01

    expressing increased amounts of human endogenous retrovirus antigens. MS patients also have increased antibody levels to these antigens. The target cells are spontaneously growing peripheral blood mononuclear cells (PBMCs) of B cell lineage, expressing human endogenous retrovirus HERV epitopes...... on their surface. Polyclonal antibodies against defined peptides in the Env- and Gag-regions of the HERVs were raised in rabbits and used in antibody-dependent cell-mediated cytotoxicity (ADCC) -assays. Rituximab® (Roche), a chimeric monoclonal antibody against CD20 expressed primarily on B cells, was used...

  19. Increased expression of beta 2-microglobulin and histocompatibility antigens on human lymphoid cells induced by interferon

    DEFF Research Database (Denmark)

    Hokland, M; Heron, I; Berg, K

    1982-01-01

    Normal human peripheral blood lymphocytes were incubated in the presence of different concentrations of interferon for various incubation periods. Subsequently, the amount of beta 2-Microglobulin and HLA-A, B and C surface antigens was estimated by means of quantitative immunofluorescence (flow...... cytofluorometry) and by a radioimmunoassay for beta 2-Microglobulin. It was found that the amounts of these MHC antigens increased in a dose and time-dependent way after interferon treatment. Furthermore, the influence of different temperatures on this IFN-induced increase in beta 2-Microglobulin was gradually...

  20. Glycoprotein on cell surfaces

    International Nuclear Information System (INIS)

    Muramatsu, T.

    1975-01-01

    There are conjugated polysaccharides in cell membranes and outside of animal cells, and they play important role in the control of cell behavior. In this paper, the studies on the glycoprotein on cell surfaces are reported. It was found that the glycoprotein on cell surfaces have both N-glycoside type and O-glycoside type saccharic chains. Therefore it can be concluded that the basic structure of the saccharic chains in the glycoprotein on cell surfaces is similar to that of blood serum and body fluid. The main glycoprotein in the membranes of red blood corpuscles has been studied most in detail, and it also has both types of saccharic chains. The glycoprotein in liver cell membranes was found to have only the saccharic chains of acid type and to be in different pattern from that in endoplasmic reticula and nuclear membranes, which also has the saccharic chains of neutral type. The structure of the saccharic chains of H-2 antigen, i.e. the peculiar glycoprotein on the surfaces of lymph system cells, has been studied, and it is similar to the saccharic chains of glycoprotein in blood serum. The saccharic chain structures of H-2 antigen and TL antigen are different. TL, H-2 (D), Lna and H-2 (K) are the glycoprotein on cell surfaces, and are independent molecules. The analysis of the saccharic chain patterns on cell surfaces was carried out, and it was shown that the acid type saccharic chains were similar to those of ordinary glycoprotein, because the enzyme of pneumococci hydrolyzed most of the acid type saccharic chains. The change of the saccharic chain patterns of glycoprotein on cell surfaces owing to canceration and multiplication is complex matter. (Kako, I.)