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Sample records for antigens surface

  1. Binding of hydrophobic antigens to surfaces

    DEFF Research Database (Denmark)

    2017-01-01

    A first aspect of the present invention is a method of detecting antibodies comprising the steps of: i) providing a first group of beads comprising a surface modified with C1-C10 alkyl groups comprising amine, ammonium, ether and/or hydroxyl groups, ii) contacting said first group of beads......-antigen-antibody conjugates, and v) detecting said bead-antigen-antibody conjugates. Further aspects include an antibody detection kit, a bead-antigen conjugate and a composition comprising at least two different groups of bead-antigen-conjugates....

  2. The value of serum Hepatitis B surface antigen quantification in ...

    African Journals Online (AJOL)

    The value of serum Hepatitis B surface antigen quantification in determining viralactivity in chronic Hepatitis B virus infection. ... ofCHB andalso higher in hepatitis e antigen positive patients compared to hepatitis e antigen negative patients.

  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. Neuronal surface antigen antibodies in limbic encephalitis

    Science.gov (United States)

    Graus, F; Saiz, A; Lai, M; Bruna, J; López, F; Sabater, L; Blanco, Y; Rey, M J.; Ribalta, T; Dalmau, J

    2008-01-01

    Objective: To report the frequency and type of antibodies against neuronal surface antigens (NSA-ab) in limbic encephalitis (LE). Methods: Analysis of clinical features, neuropathologic findings, and detection of NSA-ab using immunochemistry on rat tissue and neuronal cultures in a series of 45 patients with paraneoplastic (23) or idiopathic (22) LE. Results: NSA-ab were identified in 29 patients (64%; 12 paraneoplastic, 17 idiopathic). Thirteen patients had voltage-gated potassium channels (VGKC)-ab, 11 novel NSA (nNSA)-ab, and 5 NMDA receptor (NMDAR)-ab. nNSA-ab did not identify a common antigen and were more frequent in paraneoplastic than idiopathic LE (39% vs 9%; p = 0.03). When compared with VGKC-ab or NMDAR-ab, the nNSA associated more frequently with intraneuronal antibodies (11% vs 73%; p = 0.001). Of 12 patients (9 nNSA-ab, 2 VGKC-ab, 1 NMDAR-ab) with paraneoplastic LE and NSA-ab, concomitant intraneuronal antibodies occurred in 9 (75%). None of these 12 patients improved with immunotherapy. The autopsy of three of them showed neuronal loss, microgliosis, and cytotoxic T cell infiltrates in the hippocampus and amygdala. These findings were compatible with a T-cell mediated neuronal damage. In contrast, 13 of 17 (76%) patients with idiopathic LE and NSA-ab (8 VGKC-ab, 4 NMDAR-ab, 1 nNSA-ab) and 1 of 5 (20%) without antibodies had clinical improvement (p = 0.04). Conclusions: In paraneoplastic limbic encephalitis (LE), novel antibodies against neuronal surface antigens (nNSA-ab) occur frequently, coexist with antibodies against intracellular antigens, and these cases are refractory to immunotherapy. In idiopathic LE, the likelihood of improvement is significantly higher in patients with NSA-ab than in those without antibodies. GLOSSARY GAD = glutamic acid decarboxylase; LE = limbic encephalitis; NMDAR = N-methyl-D-aspartate receptor; NSA = neuronal surface antigens; nNSA = novel NSA; SCLC = small-cell lung cancer; VGKC = voltage-gated potassium channels

  5. Conservation of myeloid surface antigens on primate granulocytes.

    Science.gov (United States)

    Letvin, N L; Todd, R F; Palley, L S; Schlossman, S F; Griffin, J D

    1983-02-01

    Monoclonal antibodies reactive with myeloid cell surface antigens were used to study evolutionary changes in granulocyte surface antigens from primate species. Certain of these granulocyte membrane antigens are conserved in phylogenetically distant species, indicating the potential functional importance of these structures. The degree of conservation of these antigens reflects the phylogenetic relationship between primate species. Furthermore, species of the same genus show similar patterns of binding to this panel of anti-human myeloid antibodies. This finding of conserved granulocyte surface antigens suggests that non-human primates may provide a model system for exploring uses of monoclonal antibodies in the treatment of human myeloid disorders.

  6. 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.

  7. Prevalence of Hepatitis B surface antigen among pregnant women ...

    African Journals Online (AJOL)

    Prevalence of Hepatitis B surface antigen among pregnant women attending antenatal ... Majigo Mtebe, Nyambura Moremi, Jeremiah Seni, Stephen E. Mshana. Abstract. In developing countries there is no routine screening of hepatitis B virus ...

  8. 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...

  9. 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 ...

  10. 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.

  11. Novel Pneumocystis Antigen Discovery Using Fungal Surface Proteomics

    OpenAIRE

    Zheng, Mingquan; Cai, Yang; Eddens, Taylor; Ricks, David M.; Kolls, Jay K.

    2014-01-01

    Pneumonia due to the fungus Pneumocystis jirovecii is a life-threatening infection that occurs in immunocompromised patients. The inability to culture the organism as well as the lack of an annotated genome has hindered antigen discovery that could be useful in developing novel vaccine- or antibody-based therapies as well as diagnostics for this infection. Here we report a novel method of surface proteomics analysis of Pneumocystis murina that reliably detected putative surface proteins that ...

  12. Genetic diversity and antigenicity variation of Babesia bovis merozoite surface antigen-1 (MSA-1) in Thailand.

    Science.gov (United States)

    Tattiyapong, Muncharee; Sivakumar, Thillaiampalam; Takemae, Hitoshi; Simking, Pacharathon; Jittapalapong, Sathaporn; Igarashi, Ikuo; Yokoyama, Naoaki

    2016-07-01

    Babesia bovis, an intraerythrocytic protozoan parasite, causes severe clinical disease in cattle worldwide. The genetic diversity of parasite antigens often results in different immune profiles in infected animals, hindering efforts to develop immune control methodologies against the B. bovis infection. In this study, we analyzed the genetic diversity of the merozoite surface antigen-1 (msa-1) gene using 162 B. bovis-positive blood DNA samples sourced from cattle populations reared in different geographical regions of Thailand. The identity scores shared among 93 msa-1 gene sequences isolated by PCR amplification were 43.5-100%, and the similarity values among the translated amino acid sequences were 42.8-100%. Of 23 total clades detected in our phylogenetic analysis, Thai msa-1 gene sequences occurred in 18 clades; seven among them were composed of sequences exclusively from Thailand. To investigate differential antigenicity of isolated MSA-1 proteins, we expressed and purified eight recombinant MSA-1 (rMSA-1) proteins, including an rMSA-1 from B. bovis Texas (T2Bo) strain and seven rMSA-1 proteins based on the Thai msa-1 sequences. When these antigens were analyzed in a western blot assay, anti-T2Bo cattle serum strongly reacted with the rMSA-1 from T2Bo, as well as with three other rMSA-1 proteins that shared 54.9-68.4% sequence similarity with T2Bo MSA-1. In contrast, no or weak reactivity was observed for the remaining rMSA-1 proteins, which shared low sequence similarity (35.0-39.7%) with T2Bo MSA-1. While demonstrating the high genetic diversity of the B. bovis msa-1 gene in Thailand, the present findings suggest that the genetic diversity results in antigenicity variations among the MSA-1 antigens of B. bovis in Thailand. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. 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.

  14. Prediction of antigenic epitopes on protein surfaces by consensus scoring

    Directory of Open Access Journals (Sweden)

    Zhang Chi

    2009-09-01

    Full Text Available Abstract Background Prediction of antigenic epitopes on protein surfaces is important for vaccine design. Most existing epitope prediction methods focus on protein sequences to predict continuous epitopes linear in sequence. Only a few structure-based epitope prediction algorithms are available and they have not yet shown satisfying performance. Results We present a new antigen Epitope Prediction method, which uses ConsEnsus Scoring (EPCES from six different scoring functions - residue epitope propensity, conservation score, side-chain energy score, contact number, surface planarity score, and secondary structure composition. Applied to unbounded antigen structures from an independent test set, EPCES was able to predict antigenic eptitopes with 47.8% sensitivity, 69.5% specificity and an AUC value of 0.632. The performance of the method is statistically similar to other published methods. The AUC value of EPCES is slightly higher compared to the best results of existing algorithms by about 0.034. Conclusion Our work shows consensus scoring of multiple features has a better performance than any single term. The successful prediction is also due to the new score of residue epitope propensity based on atomic solvent accessibility.

  15. Radioimmunoassay for antibodies against surface membrane antigens using adhering cells

    Energy Technology Data Exchange (ETDEWEB)

    Tax, A; Manson, L A [Wistar Inst. of Anatomy and Biology, Philadelphia, Pa. (USA)

    1976-07-01

    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 /sup 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.

  16. Characterization of antigen association with accessory cells: specific removal of processed antigens from the cell surface by phospholipases

    International Nuclear Information System (INIS)

    Falo, L.D. Jr.; Haber, S.I.; Herrmann, S.; Benacerraf, B.; Rock, K.L.

    1987-01-01

    To characterize the basis for the cell surface association of processed antigen with the antigen-presenting cell (APC) the authors analyzed its sensitivity to enzymatic digestion. Antigen-exposed APC that are treated with phospholipase and then immediately fixed lose their ability to stimulate antigen-plus-Ia-specific T-T hybridomas. This effect is seen with highly purified phospholipase A 2 and phospholipase C. In addition it is observed with three distinct antigens - ovalbumin, bovine insulin, and poly(LGlu 56 LLys 35 LPhe 9 )[(GluLysPhe)/sub n/]. The effect of phospholipases is highly specific. Identically treated APC are equivalent to control in their ability to stimulate alloreactive hybridomas specific for precisely the same Ia molecule that is corecognized by antigen-plus-Ia-specific hybrids. Furthermore, the antigen-presenting function of enzyme-treated, fixed APC can be reconstituted by the addition of exogenous in vitro processed or processing independent antigens. In parallel studies 125 I-labeled avidin was shown to specifically bind to APC that were previously exposed and allowed to process biotin-insulin. Biotin-insulin-exposed APC that are pretreated with phospholipase bind significantly less 125 I-labeled avidin than do untreated, exposed APC. Identical enzyme treatment does not reduce the binding of avidin to a biotinylated antibody already bound to class II major histocompatibility complex molecules of APC. These studies demonstrate that phospholipase effectively removes processed cell surface antigen

  17. 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

  18. Concurrence of hepatitis B surface antibodies and surface antigen: implications for postvaccination control of health care workers

    NARCIS (Netherlands)

    Zaaijer, Hans L.; Lelie, P. N.; Vandenbroucke-Grauls, C. M. J. E.; Koot, M.

    2002-01-01

    Among 1081 persons testing positive for hepatitis B surface antigen, 106 (10%) tested positive for antibodies to surface antigen (anti-HBs) in the same blood sample. Thirty of these persons were studied in detail: seven tested positive for hepatitis B e-antigen, nine were apparently healthy blood

  19. A Molecular-Level Account of the Antigenic Hantaviral Surface

    Directory of Open Access Journals (Sweden)

    Sai Li

    2016-05-01

    Full Text Available Hantaviruses, a geographically diverse group of zoonotic pathogens, initiate cell infection through the concerted action of Gn and Gc viral surface glycoproteins. Here, we describe the high-resolution crystal structure of the antigenic ectodomain of Gn from Puumala hantavirus (PUUV, a causative agent of hemorrhagic fever with renal syndrome. Fitting of PUUV Gn into an electron cryomicroscopy reconstruction of intact Gn-Gc spike complexes from the closely related but non-pathogenic Tula hantavirus localized Gn tetramers to the membrane-distal surface of the virion. The accuracy of the fitting was corroborated by epitope mapping and genetic analysis of available PUUV sequences. Interestingly, Gn exhibits greater non-synonymous sequence diversity than the less accessible Gc, supporting a role of the host humoral immune response in exerting selective pressure on the virus surface. The fold of PUUV Gn is likely to be widely conserved across hantaviruses.

  20. 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.

  1. 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

  2. Evidence for glycosyl-phosphatidylinositol anchoring of Toxoplasma gondii major surface antigens

    International Nuclear Information System (INIS)

    Tomavo, S.; Schwarz, R.T.; Dubremetz, J.F.

    1989-01-01

    The four major surface antigens of Toxoplasma gondii tachyzoites (P43, P35, P30, and P22) were made water soluble by phosphatidylinositol-specific phospholipase C (PI-PLC). These antigens were biosynthetically labeled with 3 H-fatty acids, [ 3 H]ethanolamine, and [ 3 H]carbohydrates. Treatment of 3 H-fatty-acid-labeled parasite lysates with PI-PLC removed the radioactive label from these antigens. A cross-reacting determinant was exposed on these antigens after PI-PLC treatment

  3. 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

  4. CELLISA: reporter cell-based immunization and screening of hybridomas specific for cell surface antigens.

    Science.gov (United States)

    Chen, Peter; Mesci, Aruz; Carlyle, James R

    2011-01-01

    Monoclonal antibodies (mAbs) specific for cell surface antigens are an invaluable tool to study immune receptor expression and function. Here, we outline a generalized reporter cell-based approach to the generation and high-throughput screening of mAbs specific for cell surface antigens. Termed CELLISA, this technology hinges upon the capture of hybridoma supernatants in mAb arrays that facilitate ligation of an antigen of interest displayed on BWZ reporter cells in the form of a CD3ζ-fusion chimeric antigen receptor (zCAR); in turn, specific mAb-mediated cross-linking of zCAR on BWZ cells results in the production of β-galactosidase enzyme (β-gal), which can be assayed colorimetrically. Importantly, the BWZ reporter cells bearing the zCAR of interest may be used for immunization as well as screening. In addition, serial immunizations employing additional zCAR- or native antigen-bearing cell lines can be used to increase the frequency of the desired antigen-specific hybridomas. Finally, the use of a cohort of epitope-tagged zCAR (e.g., zCAR(FLAG)) variants allows visualization of the cell surface antigen prior to immunization, and coimmunization using these variants can be used to enhance the immunogenicity of the target antigen. Employing the CELLISA strategy, we herein describe the generation of mAb directed against an uncharacterized natural killer cell receptor protein.

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

    Science.gov (United States)

    Boas, Ulrik; Lind, Peter; Riber, Ulla

    2014-11-15

    A new generic method for the conjugation of lipopolysaccharide (LPS)-derived polysaccharide antigens from gram-negative bacteria has been developed using Salmonella as a model. After removal of lipid A from the LPS by mild acidolysis, the polysaccharide antigen was conjugated to polystyrene 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 °C 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 against Salmonella typhimurium and Salmonella dublin. The presented method was compared with a similar method for conjugation of Salmonella polysaccharide antigens to surfaces. Here, the new method showed higher antigen coupling efficiency by detecting low concentrations of antibodies. Furthermore, the polysaccharide-conjugated beads showed preserved bioactivity after 1 year of use. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. 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...... 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....

  7. Pooled protein immunization for identification of cell surface antigens in Streptococcus sanguinis.

    Directory of Open Access Journals (Sweden)

    Xiuchun Ge

    2010-07-01

    Full Text Available Available bacterial genomes provide opportunities for screening vaccines by reverse vaccinology. Efficient identification of surface antigens is required to reduce time and animal cost in this technology. We developed an approach to identify surface antigens rapidly in Streptococcus sanguinis, a common infective endocarditis causative species.We applied bioinformatics for antigen prediction and pooled antigens for immunization. Forty-seven surface-exposed proteins including 28 lipoproteins and 19 cell wall-anchored proteins were chosen based on computer algorithms and comparative genomic analyses. Eight proteins among these candidates and 2 other proteins were pooled together to immunize rabbits. The antiserum reacted strongly with each protein and with S. sanguinis whole cells. Affinity chromatography was used to purify the antibodies to 9 of the antigen pool components. Competitive ELISA and FACS results indicated that these 9 proteins were exposed on S. sanguinis cell surfaces. The purified antibodies had demonstrable opsonic activity.The results indicate that immunization with pooled proteins, in combination with affinity purification, and comprehensive immunological assays may facilitate cell surface antigen identification to combat infectious diseases.

  8. Pooled protein immunization for identification of cell surface antigens in Streptococcus sanguinis.

    Science.gov (United States)

    Ge, Xiuchun; Kitten, Todd; Munro, Cindy L; Conrad, Daniel H; Xu, Ping

    2010-07-26

    Available bacterial genomes provide opportunities for screening vaccines by reverse vaccinology. Efficient identification of surface antigens is required to reduce time and animal cost in this technology. We developed an approach to identify surface antigens rapidly in Streptococcus sanguinis, a common infective endocarditis causative species. We applied bioinformatics for antigen prediction and pooled antigens for immunization. Forty-seven surface-exposed proteins including 28 lipoproteins and 19 cell wall-anchored proteins were chosen based on computer algorithms and comparative genomic analyses. Eight proteins among these candidates and 2 other proteins were pooled together to immunize rabbits. The antiserum reacted strongly with each protein and with S. sanguinis whole cells. Affinity chromatography was used to purify the antibodies to 9 of the antigen pool components. Competitive ELISA and FACS results indicated that these 9 proteins were exposed on S. sanguinis cell surfaces. The purified antibodies had demonstrable opsonic activity. The results indicate that immunization with pooled proteins, in combination with affinity purification, and comprehensive immunological assays may facilitate cell surface antigen identification to combat infectious diseases.

  9. 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.

  10. Shedding of the immunodominant P20 surface antigen of Eimeria bovis sporozoites.

    OpenAIRE

    Speer, C A; Whitmire, W M

    1989-01-01

    P20 is an immunodominant surface antigen of Eimeria bovis sporozoites. As parasites underwent merogony within cultured bovine monocytes and Madin-Darby bovine kidney (MDBK) cells, P20 appeared to be shed gradually by meronts and was absent in type 1 and 2 first-generation merozoites. Meronts of E. bovis appeared to shed P20 into the parasitophorous vacuole of bovine monocytes, whereas MDBK cells evidently released P20 into the culture medium or destroyed its antigenic determinant.

  11. 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

  12. Characterisation of surface antigens of Strongylus vulgaris of potential immunodiagnostic importance.

    Science.gov (United States)

    Nichol, C; Masterson, W J

    1987-08-01

    When antigens prepared by detergent washes of Strongylus vulgaris and Parascaris equorum were probed in an enzyme-linked immunosorbent assay test with horse sera from single species infections of S. vulgaris and P. equorum, a high degree of cross-reaction between the species was demonstrated. Western blot analysis of four common horse nematode species showed a large number of common antigens when probed with horse infection sera. Antisera raised in rabbits against the four species, including S. vulgaris, were also found to cross-react considerably. Rabbit anti-S. vulgaris sera were affinity adsorbed over a series of affinity chromatography columns, bound with cross-reactive surface antigens, to obtain S. vulgaris-specific antisera and thereby identify S. vulgaris-specific antigens by Western blotting. These studies revealed potentially specific antigens of apparent molecular weights of 100,000, 52,000, and 36,000. Of these bands, only the 52 kDa and 36 kDa appeared to be found on the surface as judged by 125I-labelling of intact worms by the Iodogen method, although neither protein was immunoprecipitated by horse infection sera. Finally, immunoprecipitation of in vitro translated proteins derived from larval S. vulgaris RNA suggests that two proteins may be parasite-derived. These findings are discussed both with respect to the surface of S. vulgaris and to the use of these species-specific antigens in immunodiagnosis.

  13. 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

  14. 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.

  15. 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

  16. Strains of Sarcocystis neurona exhibit differences in their surface antigens, including the absence of the major surface antigen SnSAG1.

    Science.gov (United States)

    Howe, Daniel K; Gaji, Rajshekhar Y; Marsh, Antoinette E; Patil, Bhagyashree A; Saville, William J; Lindsay, David S; Dubey, J P; Granstrom, David E

    2008-05-01

    A gene family of surface antigens is expressed by merozoites of Sarcocystis neurona, the primary cause of equine protozoal myeloencephalitis (EPM). These surface proteins, designated SnSAGs, are immunodominant and therefore excellent candidates for development of EPM diagnostics or vaccines. Prior work had identified an EPM isolate lacking the major surface antigen SnSAG1, thus suggesting there may be some diversity in the SnSAGs expressed by different S. neurona isolates. Therefore, a bioinformatic, molecular and immunological study was conducted to assess conservation of the SnSAGs. Examination of an expressed sequence tag (EST) database revealed several notable SnSAG polymorphisms. In particular, the EST information implied that the EPM strain SN4 lacked the major surface antigen SnSAG1. The absence of this surface antigen from the SN4 strain was confirmed by both Western blot and Southern blot. To evaluate SnSAG polymorphisms in the S. neurona population, 14 strains were examined by Western blots using monospecific polyclonal antibodies against the four described SnSAGs. The results of these analyses demonstrated that SnSAG2, SnSAG3, and SnSAG4 are present in all 14 S. neurona strains tested, although some variance in SnSAG4 was observed. Importantly, SnSAG1 was not detected in seven of the strains, which included isolates from four cases of EPM and a case of fatal meningoencephalitis in a sea otter. Genetic analyses by PCR using gene-specific primers confirmed the absence of the SnSAG1 locus in six of these seven strains. Collectively, the data indicated that there is heterogeneity in the surface antigen composition of different S. neurona isolates, which is an important consideration for development of serological tests and prospective vaccines for EPM. Furthermore, the diversity reported herein likely extends to other phenotypes, such as strain virulence, and may have implications for the phylogeny of the various Sarcocystis spp. that undergo sexual stages

  17. Treatment of Schistosoma mansoni with miltefosine in vitro enhances serological recognition of defined worm surface antigens.

    Directory of Open Access Journals (Sweden)

    Marwa H El-Faham

    2017-08-01

    Full Text Available Miltefosine, an anti-cancer drug that has been successfully repositioned for treatment of Leishmania infections, has recently also shown promising effects against Schistosoma spp targeting all life cycle stages of the parasite. The current study examined the effect of treating Schistosoma mansoni adult worms with miltefosine on exposure of worm surface antigens in vitro.In an indirect immunofluorescence assay, rabbit anti-S.mansoni adult worm homogenate and anti-S. mansoni infection antisera gave strong immunofluorescence of the S. mansoni adult worm surface after treatment with miltefosine, the latter antiserum having previously been shown to synergistically enhance the schistosomicidal activity of praziquantel. Rabbit antibodies that recognised surface antigens exposed on miltefosine-treated worms were recovered by elution off the worm surface in low pH buffer and were used in a western immunoblotting assay to identify antigenic targets in a homogenate extract of adult worms (SmWH. Four proteins reacting with the antibodies in immunoblots were purified and proteomic analysis (MS/MS combined with specific immunoblotting indicated they were the S. mansoni proteins: fructose-1,6 bisphosphate aldolase (SmFBPA, Sm22.6, alkaline phosphatase and malate dehydrogenase. These antibodies were also found to bind to the surface of 3-hour schistosomula and induce immune agglutination of the parasites, suggesting they may have a role in immune protection.This study reveals a novel mode of action of miltefosine as an anti-schistosome agent. The immune-dependent hypothesis we investigated has previously been lent credence with praziquantel (PZQ, whereby treatment unmasks parasite surface antigens not normally exposed to the host during infection. Antigens involved in this molecular mechanism could have potential as intervention targets and antibodies against these antigens may act to increase the drug's anti-parasite efficacy and be involved in the development

  18. Sarcocystis neurona merozoites express a family of immunogenic surface antigens that are orthologues of the Toxoplasma gondii surface antigens (SAGs) and SAG-related sequences.

    Science.gov (United States)

    Howe, Daniel K; Gaji, Rajshekhar Y; Mroz-Barrett, Meaghan; Gubbels, Marc-Jan; Striepen, Boris; Stamper, Shelby

    2005-02-01

    Sarcocystis neurona is a member of the Apicomplexa that causes myelitis and encephalitis in horses but normally cycles between the opossum and small mammals. Analysis of an S. neurona expressed sequence tag (EST) database revealed four paralogous proteins that exhibit clear homology to the family of surface antigens (SAGs) and SAG-related sequences of Toxoplasma gondii. The primary peptide sequences of the S. neurona proteins are consistent with the two-domain structure that has been described for the T. gondii SAGs, and each was predicted to have an amino-terminal signal peptide and a carboxyl-terminal glycolipid anchor addition site, suggesting surface localization. All four proteins were confirmed to be membrane associated and displayed on the surface of S. neurona merozoites. Due to their surface localization and homology to T. gondii surface antigens, these S. neurona proteins were designated SnSAG1, SnSAG2, SnSAG3, and SnSAG4. Consistent with their homology, the SnSAGs elicited a robust immune response in infected and immunized animals, and their conserved structure further suggests that the SnSAGs similarly serve as adhesins for attachment to host cells. Whether the S. neurona SAG family is as extensive as the T. gondii SAG family remains unresolved, but it is probable that additional SnSAGs will be revealed as more S. neurona ESTs are generated. The existence of an SnSAG family in S. neurona indicates that expression of multiple related surface antigens is not unique to the ubiquitous organism T. gondii. Instead, the SAG gene family is a common trait that presumably has an essential, conserved function(s).

  19. Sarcocystis neurona Merozoites Express a Family of Immunogenic Surface Antigens That Are Orthologues of the Toxoplasma gondii Surface Antigens (SAGs) and SAG-Related Sequences†

    Science.gov (United States)

    Howe, Daniel K.; Gaji, Rajshekhar Y.; Mroz-Barrett, Meaghan; Gubbels, Marc-Jan; Striepen, Boris; Stamper, Shelby

    2005-01-01

    Sarcocystis neurona is a member of the Apicomplexa that causes myelitis and encephalitis in horses but normally cycles between the opossum and small mammals. Analysis of an S. neurona expressed sequence tag (EST) database revealed four paralogous proteins that exhibit clear homology to the family of surface antigens (SAGs) and SAG-related sequences of Toxoplasma gondii. The primary peptide sequences of the S. neurona proteins are consistent with the two-domain structure that has been described for the T. gondii SAGs, and each was predicted to have an amino-terminal signal peptide and a carboxyl-terminal glycolipid anchor addition site, suggesting surface localization. All four proteins were confirmed to be membrane associated and displayed on the surface of S. neurona merozoites. Due to their surface localization and homology to T. gondii surface antigens, these S. neurona proteins were designated SnSAG1, SnSAG2, SnSAG3, and SnSAG4. Consistent with their homology, the SnSAGs elicited a robust immune response in infected and immunized animals, and their conserved structure further suggests that the SnSAGs similarly serve as adhesins for attachment to host cells. Whether the S. neurona SAG family is as extensive as the T. gondii SAG family remains unresolved, but it is probable that additional SnSAGs will be revealed as more S. neurona ESTs are generated. The existence of an SnSAG family in S. neurona indicates that expression of multiple related surface antigens is not unique to the ubiquitous organism T. gondii. Instead, the SAG gene family is a common trait that presumably has an essential, conserved function(s). PMID:15664946

  20. Trypanosoma cruzi. Surface antigens of blood and culture forms

    International Nuclear Information System (INIS)

    Nogueira, N.; Chaplan, S.; Tydings, J.D.; Unkeless, J.; Cohn, Z.

    1981-01-01

    The surface polypeptides of both cultured and blood forms of Trypanosoma cruzi were iodinated by the glucose oxidase-lactoperoxidase technique. Blood-form trypomastigotes (BFT) isolated form infected mice displayed a major 90,000-Mr component. In contrast, both epimastigotes and trypomastigotes obtained form acellular cultures expressed a smaller 75,000-Mr peptide. Both major surface components were presumably glycoproteins in terms of their binding to concanavalin A-Sepharose 4B. Within a 3-h period, both blood and culture forms synthesized their respective surface glycoproteins (90,000 Mr and 75,000 Mr, respectively in vitro. [/sub 35/S]methionine-labeled surface peptides were immunoprecipitated with immune sera of both human and murine origin. A panel of sera form patients with chronic Chagas' disease and hyperimmunized mice recognized similar surface peptides. These immunogens were the same components as the major iodinated species. The major BFT surface peptide was readily removed by trypsin treatment of the parasites, although the procedure did not affect the 75,000-Mr peptide from the culture forms. Two-dimensional polyacrylamide gel electrophoresis revealed that the 90,000-Mr peptide found on BFT was an acidic protein of isoelectric point (pI) 5.0, whereas, the 75,000-Mr peptide form culture-form trypomastigotes has a pI of 7.2. The 90,000-Mr component is thought to be responsible for the anti-phagocytic properties of the BFT

  1. Radioimmunoassay in the detection of the hepatitis Be antigen/antibody system in asymptomatic carriers of hepatitis B surface antigen

    International Nuclear Information System (INIS)

    Pastore, G.; Dentico, P.; Angarano, G.; Schiraldi, O.; Zanetti, A.R.; Ferroni, P.

    1980-01-01

    A radioimmunoassay for hepatitis e antigen (HBeAg) and antibody to e (anti-HBe) was developed and sera of 71 asymptomatic chronic carriers of hepatitis B surface antigen (HBsAg), in 44 of whom liver biopsy was obtained, were tested. In addition, testing for Dane particle associated DNA polymerase activity was performed in all sera. HBeAg was detected in 14 subjects (19.7%) and anti-HBe in 46 (64.8%). The highest proportion of HBeAg positivity (40%) was found among carriers with histological evidence of chronic hepatitis, whereas anti-HBe was present in 80% of carriers with normal liver histology, in 58% of carriers with non-specific reactive hepatitis and in 60% of carriers with chronic liver lesions. DNA polymerase activity was present in 92.8% of sera positive for HBeAg, in 13% of sera positive for anti HBe, and in 9% of sera negative for both markers. Our results demonstrate that not all HBsAg carriers reactive to HBeAg show evidence of chronic hepatitis nor, conversely, that anti-HBe is invariably associated with the healthy carrier state of HBsAg. Finally, circulating Dane particles, as revealed by the presence of serum specific DNA polymerase activity, may also be present in anti-HBe positive sera other than those of some HBsAg carriers lacking both HBeAg and anti-HBe. (orig.) [de

  2. Use of nitrocellulose blotting for the study of hepatitis B surface antigen electrophoresed in agarose gels

    Energy Technology Data Exchange (ETDEWEB)

    McMichael, J C; Greisiger, L M; Millman, I [Institute for Cancer Research, Philadelphia, PA (USA). Fox Chase Cancer Center

    1981-08-28

    Nitrocellulose-protein blotting of serum electrophoresed in agarose gels has been adapted for the study of hepatitis B surface antigen (HBsAg). /sup 125/I-labeled anti-HBs was used as the antigen probe, and the electrophoretic migration was monitored by autoradiography. The method required 3 ..mu..l or less of serum and could detect as little as 1 pg of purified HBsAg. Typically, the authors observed two bands of HBsAg; a moving band which migrated about one-third the distance moved by human serum albumin and a non-migratory band which remained at the loading site. Some examples of the use of the method include: (1) empirical methods for correlating HBsAg concentration in serum to film darkness; (2) observations of mobility changes in serial sera from dialysis patients with chronic HBsAg antigenemia; and (3) detection of related antigens such as antigen from the PLC/PRF/5 hepatoma tissue culture line and the cross-reacting woodchuck hepatitis virus surface antigen (WHsAg).

  3. 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.)

  4. 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...

  5. 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

  6. 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

  7. 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

  8. 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 ...

  9. 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

  10. Identification of a surface antigen on Theileria parva sporozoites by monoclonal antibody.

    OpenAIRE

    Dobbelaere, D A; Shapiro, S Z; Webster, P

    1985-01-01

    A mouse monoclonal antibody (mAbD1) that neutralizes sporozoites of different stocks of the protozoan parasite Theileria parva has been used to localize and identify a sporozoite antigen. Protein A-colloidal gold was used to localize bound mAbD1 in immunoelectron microscopic studies. mAbD1 bound to sporozoite antigen, which was evenly spread over the surface of all sporozoites. Immune complexes were obtained by incubation of sporozoite suspensions with mAbD1 followed by Zwittergent 3-14 extra...

  11. Geographical and temporal conservation of antibody recognition of Plasmodium falciparum variant surface antigens

    DEFF Research Database (Denmark)

    Nielsen, Morten A; Vestergaard, Lasse S; Lusingu, John

    2004-01-01

    The slow acquisition of protection against Plasmodium falciparum malaria probably reflects the extensive diversity of important antigens. The variant surface antigens (VSA) that mediate parasite adhesion to a range of host molecules are regarded as important targets of acquired protective immunity......, but their diversity makes them questionable vaccine candidates. We determined levels of VSA-specific immunoglobulin G (IgG) in human plasma collected at four geographically distant and epidemiologically distinct localities with specificity for VSA expressed by P. falciparum isolates from three African countries...

  12. Some problems associated with radiolabeling surface antigens on helminth parasites: a brief review

    Energy Technology Data Exchange (ETDEWEB)

    Hayunga, E.G. (Division of Tropical Public Health, Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, MD (USA)); Murrell, K.D. (Agricultural Research Service, Beltsville, MD (USA))

    1982-06-01

    Recent developments in technology have facilitated substantial advances in the characterization of surface antigens from a wide variety of both normal and neoplastic cells. However, the immunochemistry of parasites has lagged behind. Efforts to apply conventional radiolabeling methods to helminths have not always been successful. Experimental work with Schistosoma mansoni is reviewed to illustrate common problems encountered in surface labeling studies. These findings should provide insight for the future investigation of other helminth species.

  13. Some problems associated with radiolabeling surface antigens on helminth parasites: a brief review

    International Nuclear Information System (INIS)

    Hayunga, E.G.; Murrell, K.D.

    1982-01-01

    Recent developments in technology have facilitated substantial advances in the characterization of surface antigens from a wide variety of both normal and neoplastic cells. However, the immunochemistry of parasites has lagged behind. Efforts to apply conventional radiolabeling methods to helminths have not always been successful. Experimental work with Schistosoma mansoni is reviewed to illustrate common problems encountered in surface labeling studies. These findings should provide insight for the future investigation of other helminth species. (Auth.)

  14. Immunogenic Properties of Lactobacillus plantarum Producing Surface-Displayed Mycobacterium tuberculosis Antigens.

    Science.gov (United States)

    Kuczkowska, Katarzyna; Kleiveland, Charlotte R; Minic, Rajna; Moen, Lars F; Øverland, Lise; Tjåland, Rannei; Carlsen, Harald; Lea, Tor; Mathiesen, Geir; Eijsink, Vincent G H

    2017-01-15

    Tuberculosis (TB) remains among the most deadly diseases in the world. The only available vaccine against tuberculosis is the bacille Calmette-Guérin (BCG) vaccine, which does not ensure full protection in adults. There is a global urgency for the development of an effective vaccine for preventing disease transmission, and it requires novel approaches. We are exploring the use of lactic acid bacteria (LAB) as a vector for antigen delivery to mucosal sites. Here, we demonstrate the successful expression and surface display of a Mycobacterium tuberculosis fusion antigen (comprising Ag85B and ESAT-6, referred to as AgE6) on Lactobacillus plantarum The AgE6 fusion antigen was targeted to the bacterial surface using two different anchors, a lipoprotein anchor directing the protein to the cell membrane and a covalent cell wall anchor. AgE6-producing L. plantarum strains using each of the two anchors induced antigen-specific proliferative responses in lymphocytes purified from TB-positive donors. Similarly, both strains induced immune responses in mice after nasal or oral immunization. The impact of the anchoring strategies was reflected in dissimilarities in the immune responses generated by the two L. plantarum strains in vivo The present study comprises an initial step toward the development of L. plantarum as a vector for M. tuberculosis antigen delivery. This work presents the development of Lactobacillus plantarum as a candidate mucosal vaccine against tuberculosis. Tuberculosis remains one of the top infectious diseases worldwide, and the only available vaccine, bacille Calmette-Guérin (BCG), fails to protect adults and adolescents. Direct antigen delivery to mucosal sites is a promising strategy in tuberculosis vaccine development, and lactic acid bacteria potentially provide easy, safe, and low-cost delivery vehicles for mucosal immunization. We have engineered L. plantarum strains to produce a Mycobacterium tuberculosis fusion antigen and to anchor this

  15. 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.

  16. 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

    . Sterile immunity is not achieved and chronic parasitization of apparently healthy adults is the norm. In this article, we analyse the best understood malaria "antigenic variation" system, that based on Plasmodium falciparum's PfEMP1-type cytoadhesion antigens, and critically review recent literature...

  17. Detection and Characterization of Autoantibodies to Neuronal Cell-Surface Antigens in the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Marleen eVan Coevorden-Hameete

    2016-05-01

    Full Text Available Autoimmune encephalitis (AIE is a group of disorders in which autoantibodies directed at antigens located on the plasma membrane of neurons induce severe neurological symptoms. In contrast to classical paraneoplastic disorders, AIE patients respond well to immunotherapy. The detection of neuronal surface autoantibodies in patients’ serum or CSF therefore has serious consequences for the patients’ treatment and follow-up and requires the availability of sensitive and specific diagnostic tests. This mini-review provides a guideline for both diagnostic and research laboratories that work on the detection of known surface autoantibodies and/or the identification of novel surface antigens. We discuss the strengths and pitfalls of different techniques for anti-neuronal antibody detection: 1 Immunohistochemistry and immunofluorescence on rat/ primate brain sections, 2 Immunocytochemistry of living cultured hippocampal neurons, 3 Cell Based Assay (CBA. In addition, we discuss the use of immunoprecipitation and mass spectrometry analysis for the detection of novel neuronal surface antigens, which is a crucial step in further disease classification and the development of novel CBAs.

  18. 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

  19. Purification and characterization of a major human Pneumocystis carinii surface antigen

    DEFF Research Database (Denmark)

    Lundgren, B; Lipschik, G Y; Kovacs, J A

    1991-01-01

    . To evaluate humoral immune responses to the human P. carinii protein, an enzyme-linked immunosorbent assay using purified protein was developed. Some, but not all, patients who subsequently developed P. carinii pneumonia demonstrated a serum antibody response to the surface antigen. Nearly all subjects...... without a history of P. carinii pneumonia had no detectable antibodies. Purified P. carinii proteins will greatly facilitate the investigation of host-P. carinii interactions....

  20. 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)

  1. Enzyme-linked immunosorbent assays for detection of equine antibodies specific to Sarcocystis neurona surface antigens.

    Science.gov (United States)

    Hoane, Jessica S; Morrow, Jennifer K; Saville, William J; Dubey, J P; Granstrom, David E; Howe, Daniel K

    2005-09-01

    Sarcocystis neurona is the primary causative agent of equine protozoal myeloencephalitis (EPM), a common neurologic disease of horses in the Americas. We have developed a set of enzyme-linked immunosorbent assays (ELISAs) based on the four major surface antigens of S. neurona (SnSAGs) to analyze the equine antibody response to S. neurona. The SnSAG ELISAs were optimized and standardized with a sample set of 36 equine sera that had been characterized by Western blotting against total S. neurona parasite antigen, the current gold standard for S. neurona serology. The recombinant SnSAG2 (rSnSAG2) ELISA showed the highest sensitivity and specificity at 95.5% and 92.9%, respectively. In contrast, only 68.2% sensitivity and 71.4% specificity were achieved with the rSnSAG1 ELISA, indicating that this antigen may not be a reliable serological marker for analyzing antibodies against S. neurona in horses. Importantly, the ELISA antigens did not show cross-reactivity with antisera to Sarcocystis fayeri or Neospora hughesi, two other equine parasites. The accuracy and reliability exhibited by the SnSAG ELISAs suggest that these assays will be valuable tools for examining the equine immune response against S. neurona infection, which may help in understanding the pathobiology of this accidental parasite-host interaction. Moreover, with modification and further investigation, the SnSAG ELISAs have potential for use as immunodiagnostic tests to aid in the identification of horses affected by EPM.

  2. A simple assay for the detection of antibodies to endocrine islet cell surface antigens

    International Nuclear Information System (INIS)

    Contreas, G.; Madsen, O.D.; Vissing, H.; Lernmark, Aa.

    1986-01-01

    A simple and sensitive immunoradiometric assay for the detection of islet cell surface antibodies (CIRMA) has been developed. Live, transformed islet cells derived from a liver metastasis of a transplantable islet cell tumor were grown in removable microtiter wells and incubated with antibody. Cell-bound antibodies were quantitated using 125 I-labelled second antibodies. The assay was used to detect islet cell antibodies present in sera from non-diabetic and diabetic BB rats and proved to be particularly effective for screening hybridoma supernatants in order to identify monoclonal antibodies recognizing islet cell surface antigens. (Auth.)

  3. Flow cytometric analysis of cell-surface and intracellular antigens in leukemia diagnosis.

    Science.gov (United States)

    Knapp, W; Strobl, H; Majdic, O

    1994-12-15

    New technology allows highly sensitive flow cytometric detection and quantitative analysis of intracellular antigens in normal and malignant hemopoietic cells. With this technology, the earliest stages of myeloid and lymphoid differentiation can easily and reliably be identified using antibodies directed against (pro-)myeloperoxidase/MPO, CD22 and CD3 antigens, respectively. Particularly for the analysis of undifferentiated acute myeloblastic leukemia (AML) cells, the immunological demonstration of intracellular MPO or its enzymatically inactive proforms is highly relevant, since other myeloid marker molecules such as CD33, CD13, or CDw65 are either not restricted to the granulomonocytic lineage or appear later in differentiation. By combining MPO staining with staining for lactoferrin (LF), undifferentiated cells can be distinguished from the granulomonocytic maturation compartment in bone marrow, since LF is selectively expressed from the myelocyte stage of differentiation onward. The list of informative intracellular antigens to be used in leukemia cell analysis will certainly expand in the near future. One candidate, intracellular CD68, has already been tested by us, and results are presented. Also dealt within this article are surface marker molecules not (as yet) widely used in leukemia cell analysis but with the potential to provide important additional information. Among them are the surface structures CD15, CD15s, CDw65, CD79a (MB-1), CD79b (B29), CD87 (uPA-R), and CD117 (c-kit).

  4. 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)

  5. 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.

  6. Mechanisms of Surface Antigenic Variation in the Human Pathogenic Fungus Pneumocystis jirovecii.

    Science.gov (United States)

    Schmid-Siegert, Emanuel; Richard, Sophie; Luraschi, Amanda; Mühlethaler, Konrad; Pagni, Marco; Hauser, Philippe M

    2017-11-07

    Microbial pathogens commonly escape the human immune system by varying surface proteins. We investigated the mechanisms used for that purpose by Pneumocystis jirovecii This uncultivable fungus is an obligate pulmonary pathogen that in immunocompromised individuals causes pneumonia, a major life-threatening infection. Long-read PacBio sequencing was used to assemble a core of subtelomeres of a single P. jirovecii strain from a bronchoalveolar lavage fluid specimen from a single patient. A total of 113 genes encoding surface proteins were identified, including 28 pseudogenes. These genes formed a subtelomeric gene superfamily, which included five families encoding adhesive glycosylphosphatidylinositol (GPI)-anchored glycoproteins and one family encoding excreted glycoproteins. Numerical analyses suggested that diversification of the glycoproteins relies on mosaic genes created by ectopic recombination and occurs only within each family. DNA motifs suggested that all genes are expressed independently, except those of the family encoding the most abundant surface glycoproteins, which are subject to mutually exclusive expression. PCR analyses showed that exchange of the expressed gene of the latter family occurs frequently, possibly favored by the location of the genes proximal to the telomere because this allows concomitant telomere exchange. Our observations suggest that (i) the P. jirovecii cell surface is made of a complex mixture of different surface proteins, with a majority of a single isoform of the most abundant glycoprotein, (ii) genetic mosaicism within each family ensures variation of the glycoproteins, and (iii) the strategy of the fungus consists of the continuous production of new subpopulations composed of cells that are antigenically different. IMPORTANCE Pneumocystis jirovecii is a fungus causing severe pneumonia in immunocompromised individuals. It is the second most frequent life-threatening invasive fungal infection. We have studied the mechanisms

  7. Recombinant hepatitis B surface antigen production in Aspergillus niger: evaluating the strategy of gene fusion to native glucoamylase

    CSIR Research Space (South Africa)

    James, ER

    2012-10-01

    Full Text Available Microbiology and Biotechnology October 2012/ Vol. 96, No.2 Recombinant hepatitis B surface antigen production in Aspergillus niger: evaluating the strategy of gene fusion to native glucoamylase ER James a,c & WH van Zyl b & PJ van Zyl c & JF Görgens..., Pretoria 0001, South Africa Abstract This study demonstrates the potential of Aspergillus niger as a candidate expression system for virus- like particle production using gene fusion. Hepatitis B surface antigen (HBsAg) production, targeted...

  8. 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.

  9. A solid phase radio immunoassay on hydrophobic membrane filters: detection of antibodies to gonocal surface antigens

    International Nuclear Information System (INIS)

    Lambden, P.R.; Watt, P.J.

    1978-01-01

    A solid phase radioimmunoassay (SPRIA) has been developed for detection of IgG antibodies to gonococcal outer membrane components. Gonococcal antigens was immobilised on a solid support by covalent coupling to CNBr-activated Sepharose in the presence of the detergent Triton X-100. Binding of specific antibody to the Sepharose-antigen complex was detected using radiolabelled Protein A as the antiglobulin. Protein A was labelled by radioacetylation with tritiated acetic anhydride, yielding a product of high specific activity and high stability. No detectable loss of activity was observed over a ten month period. The entire assay was performed on Mitex teflon hydrophobic membrane filters which held the Sepharose beads and aqueous supernatant as a discrete drop of liquid. The supernatants and incubation were easily and rapidly removed from the beads by suction on a specially-designed manifold system. This procedure removed the need for repeated and time-consuming centrifugations. Titres were obtained graphically from double log plots of cpm bound versus antiserum dilution by extrapolation of the straight line to a point corresponding to twice the control level of radioactivity binding. The assay proved to be a very reliable and simple procedure for the detection of IgG antibodies to gonococcal surface antigens. (Auth.)

  10. DNA secondary structures are associated with recombination in major Plasmodium falciparum variable surface antigen gene families

    DEFF Research Database (Denmark)

    Sander, Adam F.; Lavstsen, Thomas; Rask, Thomas Salhøj

    2014-01-01

    falciparum-erythrocyte membrane protein 1 class on the infected erythrocyte surface. Recombination clearly generates var diversity, but the nature and control of the genetic exchanges involved remain unclear. By experimental and bioinformatic identification of recombination events and genome...... of recombination during DNA replication in P. falciparum sexual stages, and that these DSS-regulated genetic exchanges generate functional and diverse P. falciparum adhesion antigens. DSS-induced recombination may represent a common mechanism for optimizing the evolvability of virulence gene families in pathogens....

  11. 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.

  12. [One example of false negative hepatitis B surface antigen (EIA) result due to variant S area strain and reagment reactiveness related to hepatitis B surface antigen].

    Science.gov (United States)

    Matsuda, Chikashi; Moriyama, Hidehiko; Taketani, Takeshi; Shibata, Hiroshi; Nagai, Atsushi

    2011-01-01

    The presence in serum of the Hepatitis B surface antigen (HBsAg), the outer envelope of the hepatitis B virus (HBV), indicates viral infection, used in laboratory tests to confirm this. We report a case of discrepancy among HBsAg test results detected between measurements in a subject with HB infection. Gene analysis demonstrated several S region gene mutations, not detected previously. We tested 12 measurements e.g., EIA, CLIA, CLEIA, F-EIA, MAT, and IC for whether they could detect our subject's HBsAg and found that it was not recognized by a method using only a single monoclonal antibody to detect HBsAg in two detection processes, in contrast to the 11 other measurements, which used two different antibodies. This case shows that amino acid substitution may cause a false negative result for HBsAg. Gene mutations known to occur in HBV, should thus trigger an awareness of the need to keep in mind that false negative results can happen in case such as ours.

  13. 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.

  14. Expression and immunological characterisation of Eimeria tenella glycosylphosphatidylinositol-anchored surface antigen-5

    Science.gov (United States)

    Ho, Sue-Kim; Nathan, Sheila; Wan, Kiew-Lian

    2016-11-01

    Eimeria tenella is the most pathogenic of the Eimeria species that infect chickens and causes huge economic losses to the poultry industry. The glycosylphosphatidylinositol-anchored surface antigen-5 (SAG5) found on the surface of the parasite has been shown to activate the chicken's immune system. In this study, recombinant SAG5 was expressed, purified and used to investigate the immune-inducing characteristics of the molecule. Chickens were immunized with purified recombinant SAG5 and sera were subjected to Enzyme-linked Immunosorbant Assay (ELISA). Results indicated that specific antibodies against rSAG5 were produced, with IgG detected at a higher level compared to IgA and IgM. Information on the immunological responses elicited by SAG5 provides essential knowledge that will contribute towards the effort to develop more effective strategies against coccidiosis.

  15. Characterization of SeseC_01411 as a surface protective antigen of Streptococcus equi ssp. zooepidemicus.

    Science.gov (United States)

    Xie, Honglin; Wei, Zigong; Ma, Chunquan; Li, Shun; Liu, Xiaohong; Fu, Qiang

    2018-06-01

    Streptococcus equi ssp. zooepidemicus (Streptococcus zooepidemicus, SEZ) is a commensal bacterium related to opportunistic infections of many species, including humans, dogs, cats, and pigs. SeseC_01411 has been proven to be immunogenic. However, its protective efficacy remained to be evaluated. In the present study, the purified recombinant SeseC_01411 could elicit a strong humoral antibody response and protect against lethal challenge with virulent SEZ in mice. Our finding confirmed that SeseC_01411 distributes on the surface of SEZ. In addition, the hyperimmune sera against SeseC_01411 could efficiently kill the bacteria in the phagocytosis test. The present study identified the immunogenic protein, SeseC_01411, as a novel surface protective antigen of SEZ. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. 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.

  17. Hepatitis B surface antigen (HBsAg) expression in plant cell culture: Kinetics of antigen accumulation in batch culture and its intracellular form.

    Science.gov (United States)

    Smith, Mark L; Mason, Hugh S; Shuler, Michael L

    2002-12-30

    The production of edible vaccines in transgenic plants and plant cell culture may be improved through a better understanding of antigen processing and assembly. The hepatitis B surface antigen (HBsAg) was chosen for study because it undergoes substantial and complex post-translational modifications, which are necessary for its immunogenicity. This antigen was expressed in soybean (Glycine max L. Merr. cv Williams 82) and tobacco NT1 (Nicotiana tabacum L.) cell suspension cultures, and HBsAg production in batch culture was characterized. The plant-derived antigen consisted predominantly of disulfide cross-linked HBsAg protein (p24(s)) dimers, which were all membrane associated. Similar to yeast, the plant-expressed HBsAg was retained intracellularly. The maximal HBsAg titers were obtained with soybean suspension cultures (20-22 mg/L) with titers in tobacco cultures being approximately 10-fold lower. For soybean cells, electron microscopy and immunolocalization demonstrated that all the HBsAg was localized to the endoplasmic reticulum (ER) and provoked dilation and proliferation of the ER network. Sucrose gradient analysis of crude extracts showed that HBsAg had a complex size distribution uncharacteristic of the antigen's normal structure of uniform 22-nm virus-like particles. The extent of authentic epitope formation was assessed by comparing total p24(s) synthesized to that reactive by polyclonal and monoclonal immunoassays. Depending on culture age, between 40% and 100% of total p24(s) was polyclonal antibody reactive whereas between 6% and 37% was recognized by a commercial monoclonal antibody assay. Possible strategies to increase HBsAg production and improve post-translational processing are discussed. Copyright 2002 Wiley Periodicals, Inc.

  18. 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

  19. Highly sensitive radioimmunoassay technique for subtyping the antibody to hepatitis B surface antigen

    Energy Technology Data Exchange (ETDEWEB)

    Fang, C T; Nath, N; Berberian, H; Dodd, R Y [American Red Cross, Blood Research Laboratory, Bethesda, MD, USA

    1978-12-01

    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.

  20. Detection of hepatitis B surface antigen by solid phase radioimmunoassay and immunometric assay (using enhanced luminescence)

    International Nuclear Information System (INIS)

    Nicholson, S.; Efandis, T.; Gust, I.

    1991-01-01

    A study was performed to assess the sensitivity and specificity of the amerlite monoclonal immunoassay for detection of hepatitis B surface antigen (HBsAG) by comparison with the Abbott Ausria II radioimmunoassay (RI). Serial bleeds from 34 patients with acute or chronic hepatitis B were tested by both assays. The Abbott Ausria II assay detected HBsAG longer than the Amersham Amerlite assay on two occasions and earlier on one occasion. Twelve patients with low HBsAg positive results (confirmed by Ausria II) were tested by the Amerlite assay, four were repeatably positive, five repeatably negative and three gave borderline results (which on repeat testing were negative). A similar trend was seen when a panel of sera containing known concentrations of HBsAG was tested. Replicate testing of 10 specimens eight times showed very good reproducibility by the Amerlite assay. Overall, the specificity of both assays was comparable, however differences in sensitivity were observed. 3 tabs

  1. 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.

  2. 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.)

  3. 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

  4. 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...

  5. Small-angle neutron scattering study of recombinant yeast-derived human hepatitis B virus surface antigen vaccine particle

    Science.gov (United States)

    Sato, M.; Ito, Y.; Kameyama, K.; Imai, M.; Ishikawa, N.; Takagi, T.

    1995-02-01

    The overall and internal structure of recombinant yeast-derived human hepatitis B virus surface antigen vaccine particles was investigated by small-angle neutron scattering using the contrast variation method. The vaccine is a nearly spherical particle, and its contrast-matching point was determined to be at about 24% D 2O content, indicating that a large part of the vaccine particle is occupied by lipids and carbohydrates from the yeast. The Stuhrmann plot suggests that the surface antigens exist predominantly in the peripheral region of the particle, which is favorable to the induction of anti-virus antibodies.

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

    Directory of Open Access Journals (Sweden)

    Arnot David E

    2008-06-01

    Full Text Available Abstract Background The insertion of parasite antigens into the host erythrocyte membrane and the structure and distribution of Plasmodium falciparum adhesion receptors on that membrane are poorly understood. Laser scanning confocal microscopy (LSCM and a novel labelling and fixation method have been used to obtain high resolution immuno-fluorescent images of erythrocyte surface PfEMP1 and internal antigens which allow analysis of the accumulation of PfEMP1 on the erythrocyte membrane during asexual development. Methods A novel staining technique has been developed which permits distinction between erythrocyte surface PfEMP1 and intracellular PfEMP1, in parasites whose nuclear material is exceptionally well resolved. Primary antibody detection by fluorescence is carried out on the live parasitized erythrocyte. The surface labelled cells are then fixed using paraformaldehyde and permeabilized with a non-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 of intracellular parasite development although the improved detection method indicates that there are differences between different laboratory isolates in the kinetics of accumulation of surface-exposed PfEMP1. Conclusion A sensitive method for labelling surface and internal PfEMP1 with up to three different fluorochromes has been developed for laser scanning confocal optical microscopy and the analysis of the developmental expression of malaria adhesion antigens.

  7. 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

  8. 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.

  9. Identification of new meningococcal serogroup B surface antigens through a systematic analysis of neisserial genomes.

    Science.gov (United States)

    Pajon, Rolando; Yero, Daniel; Niebla, Olivia; Climent, Yanet; Sardiñas, Gretel; García, Darién; Perera, Yasser; Llanes, Alejandro; Delgado, Maité; Cobas, Karem; Caballero, Evelin; Taylor, Stephen; Brookes, Charlotte; Gorringe, Andrew

    2009-12-11

    The difficulty of inducing an effective immune response against the Neisseria meningitidis serogroup B capsular polysaccharide has lead to the search for vaccines for this serogroup based on outer membrane proteins. The availability of the first meningococcal genome (MC58 strain) allowed the expansion of high-throughput methods to explore the protein profile displayed by N. meningitidis. By combining a pan-genome analysis with an extensive experimental validation to identify new potential vaccine candidates, genes coding for antigens likely to be exposed on the surface of the meningococcus were selected after a multistep comparative analysis of entire Neisseria genomes. Eleven novel putative ORF annotations were reported for serogroup B strain MC58. Furthermore, a total of 20 new predicted potential pan-neisserial vaccine candidates were produced as recombinant proteins and evaluated using immunological assays. Potential vaccine candidate coding genes were PCR-amplified from a panel of representative strains and their variability analyzed using maximum likelihood approaches for detecting positive selection. Finally, five proteins all capable of inducing a functional antibody response vs N. meningitidis strain CU385 were identified as new attractive vaccine candidates: NMB0606 a potential YajC orthologue, NMB0928 the neisserial NlpB (BamC), NMB0873 a LolB orthologue, NMB1163 a protein belonging to a curli-like assembly machinery, and NMB0938 (a neisserial specific antigen) with evidence of positive selection appreciated for NMB0928. The new set of vaccine candidates and the novel proposed functions will open a new wave of research in the search for the elusive neisserial vaccine.

  10. Surface antigens contribute differently to the pathophysiological features in serotype K1 and K2 Klebsiella pneumoniae strains isolated from liver abscesses.

    Science.gov (United States)

    Yeh, Kuo-Ming; Chiu, Sheng-Kung; Lin, Chii-Lan; Huang, Li-Yueh; Tsai, Yu-Kuo; Chang, Jen-Chang; Lin, Jung-Chung; Chang, Feng-Yee; Siu, Leung-Kei

    2016-01-01

    The virulence role of surface antigens in a single serotype of Klebsiella pneumoniae strain have been studied, but little is known about whether their contribution will vary with serotype. To investigate the role of K and O antigen in hyper-virulent strains, we constructed O and K antigen deficient mutants from serotype K1 STL43 and K2 TSGH strains from patients with liver abscess, and characterized their virulence in according to the abscess formation and resistance to neutrophil phagocytosis, serum, and bacterial clearance in liver. Both of K1 and K2-antigen mutants lost their wildtype resistance to neutrophil phagocytosis and hepatic clearance, and failed to cause abscess formation. K2-antigen mutant became serum susceptible while K1-antigen mutant maintained its resistance to serum killing. The amount of glucuronic acid, indicating the amount of capsular polysaccharide (CPS, K antigen), was inversed proportional to the rate of phagocytosis. O-antigen mutant of serotype K1 strains had significantly more amount of CPS, and more resistant to neutrophil phagocytosis than its wildtype counterpart. O-antigen mutants of serotype K1 and K2 strains lost their wildtype serum resistance, and kept resistant to neutrophil phagocytosis. While both mutants lacked the same O1 antigen, O-antigen mutant of serotype K1 became susceptible to liver clearance and cause mild abscess formation, but its serotype K2 counterpart maintained these wildtype virulence. We conclude that the contribution of surface antigens to virulence of K. pneumoniae strains varies with serotypes.

  11. 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

  12. 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

  13. 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...

  14. 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 g...

  15. 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

    Melanoma antigen recognized by T cell 1 (MART-1) is regarded as a candidate peptide for vaccination against malignant melanoma, and it is of importance to develop strategies to improve the vaccine-elicited T-cell activation towards MART-1. T-cell activation is, among other determinants, dependent...... 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...... to non-proteasomal targeting of the epitope to increase its cell-surface presentation. Furthermore, we explored the potential of incorporating multiple minigenes instead of one to increase cell-surface presentation. We show that both proteasomal targeting and repetition of the minigene increase cell...

  16. 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

  17. Immunogenic Eimeria tenella glycosylphosphatidylinositol-anchored surface antigens (SAGs induce inflammatory responses in avian macrophages.

    Directory of Open Access Journals (Sweden)

    Yock-Ping Chow

    Full Text Available At least 19 glycosylphosphatidylinositol (GPI-anchored surface antigens (SAGs are expressed specifically by second-generation merozoites of Eimeria tenella, but the ability of these proteins to stimulate immune responses in the chicken is unknown.Ten SAGs, belonging to two previously defined multigene families (A and B, were expressed as soluble recombinant (r fusion proteins in E. coli. Chicken macrophages were treated with purified rSAGs and changes in macrophage nitrite production, and in mRNA expression profiles of inducible nitric oxide synthase (iNOS and of a panel of cytokines were measured. Treatment with rSAGs 4, 5, and 12 induced high levels of macrophage nitric oxide production and IL-1β mRNA transcription that may contribute to the inflammatory response observed during E. tenella infection. Concomitantly, treatment with rSAGs 4, 5 and 12 suppressed the expression of IL-12 and IFN-γ and elevated that of IL-10, suggesting that during infection these molecules may specifically impair the development of cellular mediated immunity.In summary, some E. tenella SAGs appear to differentially modulate chicken innate and humoral immune responses and those derived from multigene family A (especially rSAG 12 may be more strongly linked with E. tenella pathogenicity associated with the endogenous second generation stages.

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

    International Nuclear Information System (INIS)

    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

    2011-01-01

    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 2= 0.838, P 2= 0.067, P=0.316 by IRMA, and R 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

  19. Expressed var gene repertoire and variant surface antigen diversity in a shrinking Plasmodium falciparum population.

    Science.gov (United States)

    Carlos, Bianca C; Fotoran, Wesley L; Menezes, Maria J; Cabral, Fernanda J; Bastos, Marcele F; Costa, Fabio T M; Sousa-Neto, Jayme A; Ribolla, Paulo E M; Wunderlich, Gerhard; Ferreira, Marcelo U

    2016-11-01

    The var gene-encoded erythrocyte membrane protein-1 of Plasmodium falciparum (PfEMP-1) is the main variant surface antigen (VSA) expressed on infected erythrocytes. The rate at which antibody responses to VSA expressed by circulating parasites are acquired depends on the size of the local VSA repertoire and the frequency of exposure to new VSA. Because parasites from areas with declining malaria endemicity, such as the Amazon, typically express a restricted PfEMP-1 repertoire, we hypothesized that Amazonians would rapidly acquire antibodies to most locally circulating VSA. Consistent with our expectations, the analysis of 5878 sequence tags expressed by 10 local P. falciparum samples revealed little PfEMP-1 DBL1α domain diversity. Among the most commonly expressed DBL1α types, 45% were shared by two or more independent parasite lines. Nevertheless, Amazonians displayed major gaps in their repertoire of anti-VSA antibodies, although the breadth of anti-VSA antibody responses correlated positively with their cumulative exposure to malaria. We found little antibody cross-reactivity even when testing VSA from related parasites expressing the same dominant DBL1α types. We conclude that variant-specific immunity to P. falciparum VSAs develops slowly despite the relatively restricted PfEMP-1 repertoire found in low-endemicity settings. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. 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.

  1. Evaluation of a semi-automatic radioimmunoassay for hepatitis B surface antigen (HBsAg)

    International Nuclear Information System (INIS)

    Vries, J. de; Kruining, J.; Heijtink, R.A.

    1983-01-01

    The recently developed semi-automatic Hepatube system was evaluated in comparison to another radioimmunoassay for the detection of hepatitis B surface antigen (HBsAg), the manual Ausria II-125 test. After incubation of serum in anti-HBs coated tubes, the Hepatube system uses a machine to wash the tubes and to add tracer. After a second incubation, tubes are washed again in the machine and are manually transferred to the #betta# counter. Two machines were used. Machine 1 had an undefined defect. Of 1490 samples tested, 69 (4.6%) gave false-positive results versus 11 (0.7%) in the Ausria II-125 test. Machine 2 had one false-positive result among 920 samples versus 5 in the Ausria II-125 test. The sensitivity was measured with reference panels from Wellcome and Abbott as well as in titration series. The Hepatube system was found to be a factor three less sensitive than the Ausria II-125 test. The Hepatube processor is easy to handle; radioactive material can be held at a distance during the whole procedure; waste material is limited and less voluminous than in the Ausria II-125 test. (Auth.)

  2. Transcriptional regulation of the Borrelia burgdorferi antigenically variable VlsE surface protein.

    Science.gov (United States)

    Bykowski, Tomasz; Babb, Kelly; von Lackum, Kate; Riley, Sean P; Norris, Steven J; Stevenson, Brian

    2006-07-01

    The Lyme disease agent Borrelia burgdorferi can persistently infect humans and other animals despite host active immune responses. This is facilitated, in part, by the vls locus, a complex system consisting of the vlsE expression site and an adjacent set of 11 to 15 silent vls cassettes. Segments of nonexpressed cassettes recombine with the vlsE region during infection of mammalian hosts, resulting in combinatorial antigenic variation of the VlsE outer surface protein. We now demonstrate that synthesis of VlsE is regulated during the natural mammal-tick infectious cycle, being activated in mammals but repressed during tick colonization. Examination of cultured B. burgdorferi cells indicated that the spirochete controls vlsE transcription levels in response to environmental cues. Analysis of PvlsE::gfp fusions in B. burgdorferi indicated that VlsE production is controlled at the level of transcriptional initiation, and regions of 5' DNA involved in the regulation were identified. Electrophoretic mobility shift assays detected qualitative and quantitative changes in patterns of protein-DNA complexes formed between the vlsE promoter and cytoplasmic proteins, suggesting the involvement of DNA-binding proteins in the regulation of vlsE, with at least one protein acting as a transcriptional activator.

  3. 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)

  4. 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.

  5. [Optimization of prokaryotic expression conditions of Leptospira interrogans trigeminy genus-specific protein antigen based on surface response analysis].

    Science.gov (United States)

    Wang, Jiang; Luo, Dongjiao; Sun, Aihua; Yan, Jie

    2008-07-01

    Lipoproteins LipL32 and LipL21 and transmembrane protein OMPL1 have been confirmed as the superficial genus-specific antigens of Leptospira interrogans, which can be used as antigens for developing a universal genetic engineering vaccine. In order to obtain high expression of an artificial fusion gene lipL32/1-lipL21-ompL1/2, we optimized prokaryotic expression conditions. We used surface response analysis based on the central composite design to optimize culture conditions of a new antigen protein by recombinant Escherichia coli DE3.The culture conditions included initial pH, induction start time, post-induction time, Isopropyl beta-D-thiogalactopyranoside (IPTG) concentration, and temperature. The maximal production of antigen protein was 37.78 mg/l. The optimal culture conditions for high recombinant fusion protein was determined: initial pH 7.9, induction start time 2.5 h, a post-induction time of 5.38 h, 0.20 mM IPTG, and a post-induction temperature of 31 degrees C. Surface response analysis based on CCD increased the target production. This statistical method reduced the number of experiments required for optimization and enabled rapid identification and integration of the key culture condition parameters for optimizing recombinant protein expression.

  6. A portion of the Pf155/RESA antigen of Plasmodium falciparum is accessible on the surface of infected erythrocytes

    International Nuclear Information System (INIS)

    Saul, A.; Maloy, W.L.; Howard, R.J.; Rock, E.P.

    1988-01-01

    An investigation of antigens accessible to lactoperoxidase-catalysed cell surface iodination on intact Plasmodium falciparum-infected red blood cells (RBC) has identified a 125 I-labelled antigen with an apparent size of about 155 kD. This labelled protein was specifically immunoprecipitated by the following antibodies: a rabbit antiserum and a mouse monoclonal antibody raised against a synthetic peptide comprising the 3',8-mer repeat EENVEHDA of the Pf155/RESA protein; a rabbit antiserum raised against a synthetic octapeptide comprising two copies of the 3',4-mer repeat EENV of the Pf155/RESA protein; and rabbit antisera against another synthetic peptide C(MYSNNNVED) 2 . The last antibody shows a strong reaction in asexual blood state parasites with the Pf155/RESA antigen. While this antigen has been described previously as a submembrane component of the outer membrane of infected RBC, this report shows that at least part of it is accessible to the surface of both ring and late trophozoite-infected erythrocytes. 21 refs., 4 figs

  7. 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.

  8. A rapid one-step radiometric assay for hepatitis B surface antigen utilising monoclonal antibodies

    International Nuclear Information System (INIS)

    Goodall, A.H.; Meek, F.L.; Waters, J.A.; Miescher, G.C.; Janossy, G.; Thomas, H.C.

    1982-01-01

    A two-site antigen assay for HBsAg has been developed that employs 3 monoclonal antibodies. The antibodies were selected for their high affinity and their particular epitope specificity to establish an assay with a sensitivity for the antigen comparable with that of a conventional assay with heterologous antisera. In addition, by selecting a monoclonal antibody for use as a tracer which does not compete for antigenic binding sites with the solid-phase monoclonal antibodies, it has been possible to perform a two-site assay in a single 1 h incubation step, achieving the same degree of sensitivity. This principle of using monoclonal antibodies in a one-step assay therefore gives advantages of speed and simplicity over assays using heterologous antisera and would be applicable to a variety of antigen assays for which appropriate monoclonal antibodies are available. (Auth.)

  9. Strong Antibody Responses Induced by Protein Antigens Conjugated onto the Surface of Lecithin-Based Nanoparticles

    Science.gov (United States)

    Sloat, Brian R.; Sandoval, Michael A.; Hau, Andrew M.; He, Yongqun; Cui, Zhengrong

    2009-01-01

    An accumulation of research over the years has demonstrated the utility of nanoparticles as antigen carriers with adjuvant activity. Herein we defined the adjuvanticity of a novel lecithin-based nanoparticle engineered from emulsions. The nanoparticles were spheres of around 200 nm. Model protein antigens, bovine serum albumin (BSA) or Bacillus anthracis protective antigen (PA) protein, were covalently conjugated onto the nanoparticles. Mice immunized with the BSA-conjugated nanoparticles developed strong anti-BSA antibody responses comparable to that induced by BSA adjuvanted with incomplete Freund's adjuvant and 6.5-fold stronger than that induced by BSA adsorbed onto aluminum hydroxide. Immunization of mice with the PA-conjugated nanoparticles elicited a quick, strong, and durable anti-PA antibody response that afforded protection of the mice against a lethal dose of anthrax lethal toxin challenge. The potent adjuvanticity of the nanoparticles was likely due to their ability to move the antigens into local draining lymph nodes, to enhance the uptake of the antigens by antigen-presenting cells (APCs), and to activate APCs. This novel nanoparticle system has the potential to serve as a universal protein-based vaccine carrier capable of inducing strong immune responses. PMID:19729045

  10. Evaluation of two reverse passive haemagglutination techniques and a solid-phase radioimmunoassay for detection of hepatitis B surface antigen

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, H [Beijing Medical College (China); Coulepis, A G; Gust, I D [Fairfield Hospital for Communicable Diseases, Melbourne (Australia)

    1972-08-01

    The sensitivity and specificity of two commercially available reverse passive haemagglutination tests (Hepatest and Raphadex B) for the detection of hepatitis B surface antigen, were compared with the most widely used radioimmunoassay (Ausria II-125). A selected group of 282 sera were tested: these included the Australian hepatitis B reference panel, and a batch of 257 sera collected from patients with acute hepatitis B, chronic carriers of hepatitis B surface antigen and two populations in which hepatitis B virus infection is known to be endemic. The two reverse passive haemagglutination techniques were of comparable sensitivity but slightly less sensitive than radioimmunoassay. While radioimmunoassay still remains the test of choice for blood transfusion services, the reverse passive haemagglutination techniques are of great value for smaller laboratories and for field studies because of their longer shelf life, the absence of radioactive reagents and the lack of need to acquire a gammacounter.

  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. Prevalence of Hepatitis B Surface Antigen in Pregnant Women in Beheshti Hospital of Kashan, Isfahan.

    Science.gov (United States)

    Afzali, Hasan; Momen Heravi, Mansooreh; Moravveji, Seyyed Alireza; Poorrahnama, Maryam

    2015-07-01

    The transmission of hepatitis B virus (HBV) is parenteral, sexual and prenatal. Prevention of vertical transmission of HBV is extremely important, because HBV infection in early life usually results in a chronic carrier state. There has been so much debate about hepatitis B surface antigen (HBsAg) screening in pregnant women. The aim of this study was to determine the prevalence of HBsAg+ among pregnant women referred to Beheshti hospital in Kashan in 2012. This descriptive study was carried out on 768 pregnant women, hospitalized in Beheshti Hospital of Kashan in 2012. After obtaining consent forms, the questionnaires including demographic and HBV infection-associated risk factors were filled through interview and then 5 mL blood was taken from each patient and HBsAg was examined by the enzyme-linked immunosorbent assay (ELISA) method. These data were analyzed by statistical package for the social science (SPSS) software. A total of 12 (1.56%) out of 768 pregnant women were HBsAg+. The mean age of HBsAg+ cases was 24.5 ± 4 years. Most of the HBsAg+ cases (66.6%) were uneducated; 17.7% of the pregnant women were not Iranian, of which 7.4% were HBsAg+. There was no high-risk job, recent dentistry interruption or skin tattoo among the HBsAg+ cases. In this study, 1.56% of pregnant women were HBsAg+, which was higher than the previous studies. This increasing prevalence may be due to the increase of non-Iranians' migrations to Iran. Control of migration and screening and vaccination of these groups should be considered by health policy makers.

  13. Molecular characterisation and the protective immunity evaluation of Eimeria maxima surface antigen gene.

    Science.gov (United States)

    Liu, Tingqi; Huang, Jingwei; Li, Yanlin; Ehsan, Muhammad; Wang, Shuai; Zhou, Zhouyang; Song, Xiaokai; Yan, Ruofeng; Xu, Lixin; Li, Xiangrui

    2018-05-30

    Coccidiosis is recognised as a major parasitic disease in chickens. Eimeria maxima is considered as a highly immunoprotective species within the Eimeria spp. family that infects chickens. In the present research, the surface antigen gene of E. maxima (EmSAG) was cloned, and the ability of EmSAG to stimulate protection against E. maxima was evaluated. Prokaryotic and eukaryotic plasmids expressing EmSAG were constructed. The EmSAG transcription and expression in vivo was performed based on the RT-PCR and immunoblot analysis. The expression of EmSAG in sporozoites and merozoites was detected through immunofluorescence analyses. The immune protection was assessed based on challenge experiments. Flow cytometry assays were used to determine the T cell subpopulations. The serum antibody and cytokine levels were evaluated by ELISA. The open reading frame (ORF) of EmSAG gene contained 645 bp encoding 214 amino acid residues. The immunoblot and RT-PCR analyses indicated that the EmSAG gene were transcribed and expressed in vivo. The EmSAG proteins were expressed in sporozoite and merozoite stages of E. maxima by the immunofluorescence assay. Challenge experiments showed that both pVAX1-SAG and the recombinant EmSAG (rEmSAG) proteins were successful in alleviating jejunal lesions, decreasing loss of body weight and the oocyst ratio. Additionally, these experiments possessed anticoccidial indices (ACI) of more than 170. Higher percentages of CD4 + and CD8 + T cells were detected in both EmSAG-inoculated birds than those of the negative control groups (P maxima.

  14. 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.

  15. Genotypic diversity of merozoite surface antigen 1 of Babesia bovis within an endemic population.

    Science.gov (United States)

    Lau, Audrey O T; Cereceres, Karla; Palmer, Guy H; Fretwell, Debbie L; Pedroni, Monica J; Mosqueda, Juan; McElwain, Terry F

    2010-08-01

    Multiple genetically distinct strains of a pathogen circulate and compete for dominance within populations of animal reservoir hosts. Understanding the basis for genotypic strain structure is critical for predicting how pathogens respond to selective pressures and how shifts in pathogen population structure can lead to disease outbreaks. Evidence from related Apicomplexans such as Plasmodium, Toxoplasma, Cryptosporidium and Theileria suggests that various patterns of population dynamics exist, including but not limited to clonal, oligoclonal, panmictic and epidemic genotypic strain structures. In Babesia bovis, genetic diversity of variable merozoite surface antigen (VMSA) genes has been associated with disease outbreaks, including in previously vaccinated animals. However, the extent of VMSA diversity within a defined population in an endemic area has not been examined. We analyzed genotypic diversity and temporal change of MSA-1, a member of the VMSA family, in individual infected animals within a reservoir host population. Twenty-eight distinct MSA-1 genotypes were identified within the herd. All genotypically distinct MSA-1 sequences clustered into three groups based on sequence similarity. Two thirds of the animals tested changed their dominant MSA-1 genotypes during a 6-month period. Five animals within the population contained multiple genotypes. Interestingly, the predominant genotypes within those five animals also changed over the 6-month sampling period, suggesting ongoing transmission or emergence of variant MSA-1 genotypes within the herd. This study demonstrated an unexpected level of diversity for a single copy gene in a haploid genome, and illustrates the dynamic genotype structure of B. bovis within an individual animal in an endemic region. Co-infection with multiple diverse MSA-1 genotypes provides a basis for more extensive genotypic shifts that characterizes outbreak strains.

  16. Clinical performance of a new hepatitis B surface antigen quantitative assay with automatic dilution

    Directory of Open Access Journals (Sweden)

    Ta-Wei Liu

    2015-01-01

    Full Text Available Hepatitis B virus surface antigen (HBsAg levels reflect disease status and can predict the clinical response to antiviral treatment; however, the emergence of HBsAg mutant strains has become a challenge. The Abbott HBsAg quantification assay provides enhanced detection of HBsAg and HBsAg mutants. We aimed to evaluate the performance of the Abbott HBsAg quantification assay with automatic sample dilutions (shortened as automatic Architect assay, compared with the Abbott HBsAg quantification assay with manual sample dilutions (shortened as manual Architect assay and the Roche HBsAg quantification assay with automatic sample dilutions (shortened as Elecsys. A total of 130 sera samples obtained from 87 hepatitis B virus (HBV-infected patients were collected to assess the correlation between the automatic and manual Architect assays. Among the 87 patients, 41 provided 42 sera samples to confirm the linearity and reproducibility of the automatic Architect assay, and find out the correlation among the Elecsys and two Architect assays. The coefficients of variation (0.44–9.53% and R2 = 0.996–1, which were both determined using values obtained from the automatic Architect assay, showed good reproducibility and linearity. Results of the two Architect assays demonstrated a feasible correlation (n = 130 samples; R = 0.898, p  0.93 in all cases. In conclusion, the correlation between the automatic and manual dilution Architect assays was feasible, particularly in the HBeAg-negative and low DNA groups. With lower labor costs and less human error than the manual version, the Abbott automatic dilution Architect assay provided a good clinical performance with regard to the HBsAg levels.

  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. Correlative Light-Electron Microscopy of Lipid-Encapsulated Fluorescent Nanodiamonds for Nanometric Localization of Cell Surface Antigens.

    Science.gov (United States)

    Hsieh, Feng-Jen; Chen, Yen-Wei; Huang, Yao-Kuan; Lee, Hsien-Ming; Lin, Chun-Hung; Chang, Huan-Cheng

    2018-02-06

    Containing an ensemble of nitrogen-vacancy centers in crystal matrices, fluorescent nanodiamonds (FNDs) are a new type of photostable markers that have found wide applications in light microscopy. The nanomaterial also has a dense carbon core, making it visible to electron microscopy. Here, we show that FNDs encapsulated in biotinylated lipids (bLs) are useful for subdiffraction imaging of antigens on cell surface with correlative light-electron microscopy (CLEM). The lipid encapsulation enables not only good dispersion of the particles in biological buffers but also high specific labeling of live cells. By employing the bL-encapsulated FNDs to target CD44 on HeLa cell surface through biotin-mediated immunostaining, we obtained the spatial distribution of these antigens by CLEM with a localization accuracy of ∼50 nm in routine operations. A comparative study with dual-color imaging, in which CD44 was labeled with FND and MICA/MICB was labeled with Alexa Fluor 488, demonstrated the superior performance of FNDs as fluorescent fiducial markers for CLEM of cell surface antigens.

  19. A molecular approach to immunoscintigraphy: A study of the T-antigen conformation on the surface of tumors

    International Nuclear Information System (INIS)

    Noujaim, A.; Selvaraj, S.; Suresh, M.R.; Turner, C.; McLean, G.; Willans, D.; Longenecker, B.M.; Haines, D.M.

    1987-01-01

    The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both α and β configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models. (orig.) [de

  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. Use of radio-immuno-inhibition assay for the study of the y, d and w determinants of hepatitis B surface antigen

    Energy Technology Data Exchange (ETDEWEB)

    Donea-Debroise, B; Brocteur, J; Andre, A; Remacle, M B [Liege Univ. (Belgium)

    1979-01-01

    A radioimmunoassay determination of the HBs antigen subtypes is discussed, this simple but effective technique was used in association with the use of the Austria II kit (Abbott Laboratories). This method consists of an inhibition reaction of the Austria II test, by previous incubation of the antigen to be subtyped with a monospecific antibody. With this method we were able to distinguish the y and the d antigens as well as the w1, w3, w4 determinants of hepatitis B surface antigen. We have included a frequency table of the various HBs subtypes found among donor and patient populations in Liege.

  2. The use of radio-immuno-inhibition assay for the study of the y, d and w determinants of hepatitis B surface antigen

    International Nuclear Information System (INIS)

    Donea-Debroise, B.; Brocteur, J.; Andre, A.; Remacle, M.B.

    1979-01-01

    A radioimmunoassay determination of the HBs antigen subtypes is discussed, this simple but effective technique was used in association with the use of the Austria II kit (Abbott Laboratories). This method consists of an inhibition reaction of the Austria II test, by previous incubation of the antigen to be subtyped with a monospecific antibody. With this method we were able to distinguish the y and the d antigens as well as the w1, w3, w4 determinants of hepatitis B surface antigen. We have included a frequency table of the various HBs subtypes found among donor and patient populations in Liege

  3. 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 to statistic......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...... 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......) 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....

  4. 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.

  5. 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......(PAM)-specific immunity to pregnancy-associated malaria....

  6. Genetic diversity of merozoite surface antigens in Babesia bovis detected from Sri Lankan cattle.

    Science.gov (United States)

    Sivakumar, Thillaiampalam; Okubo, Kazuhiro; Igarashi, Ikuo; de Silva, Weligodage Kumarawansa; Kothalawala, Hemal; Silva, Seekkuge Susil Priyantha; Vimalakumar, Singarayar Caniciyas; Meewewa, Asela Sanjeewa; Yokoyama, Naoaki

    2013-10-01

    Babesia bovis, the causative agent of severe bovine babesiosis, is endemic in Sri Lanka. The live attenuated vaccine (K-strain), which was introduced in the early 1990s, has been used to immunize cattle populations in endemic areas of the country. The present study was undertaken to determine the genetic diversity of merozoite surface antigens (MSAs) in B. bovis isolates from Sri Lankan cattle, and to compare the gene sequences obtained from such isolates against those of the K-strain. Forty-four bovine blood samples isolated from different geographical regions of Sri Lanka and judged to be B. bovis-positive by PCR screening were used to amplify MSAs (MSA-1, MSA-2c, MSA-2a1, MSA-2a2, and MSA-2b), AMA-1, and 12D3 genes from parasite DNA. Although the AMA-1 and 12D3 gene sequences were highly conserved among the Sri Lankan isolates, the MSA gene sequences from the same isolates were highly diverse. Sri Lankan MSA-1, MSA-2c, MSA-2a1, MSA-2a2, and MSA-2b sequences clustered within 5, 2, 4, 1, and 9 different clades in the gene phylograms, respectively, while the minimum similarity values among the deduced amino acid sequences of these genes were 36.8%, 68.7%, 80.3%, 100%, and 68.3%, respectively. In the phylograms, none of the Sri Lankan sequences fell within clades containing the respective K-strain sequences. Additionally, the similarity values for MSA-1 and MSA-2c were 40-61.8% and 90.9-93.2% between the Sri Lankan isolates and the K-strain, respectively, while the K-strain MSA-2a/b sequence shared 64.5-69.8%, 69.3%, and 70.5-80.3% similarities with the Sri Lankan MSA-2a1, MSA-2a2, and MSA-2b sequences, respectively. The present study has shown that genetic diversity among MSAs of Sri Lankan B. bovis isolates is very high, and that the sequences of field isolates diverged genetically from the K-strain. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Positive hepatitis B surface antigen tests due to recent vaccination: a persistent problem

    Directory of Open Access Journals (Sweden)

    Rysgaard Carolyn D

    2012-09-01

    Full Text Available Abstract Background Hepatitis B virus (HBV is a common cause of viral hepatitis with significant health complications including cirrhosis and hepatocellular carcinoma. Assays for hepatitis B surface antigen (HBsAg are the most frequently used tests to detect HBV infection. Vaccination for HBV can produce transiently detectable levels of HBsAg in patients. However, the time course and duration of this effect is unclear. The objective of this retrospective study was to clarify the frequency and duration of transient HBsAg positivity following vaccination against HBV. Methods The electronic medical record at an academic tertiary care medical center was searched to identify all orders for HBsAg within a 17 month time period. Detailed chart review was performed to identify all patients who were administered HBV vaccine within 180 days prior to HBsAg testing and also to ascertain likely cause of weakly positive (grayzone results. Results During the 17 month study period, 11,719 HBsAg tests were ordered on 9,930 patients. There were 34 tests performed on 34 patients who received HBV vaccine 14 days or less prior to HBsAg testing. Of these 34 patients, 11 had grayzone results for HBsAg that could be attributed to recent vaccination. Ten of the 11 patients were renal dialysis patients who were receiving HBsAg testing as part of routine and ongoing monitoring. Beyond 14 days, there were no reactive or grayzone HBsAg tests that could be attributed to recent HBV vaccination. HBsAg results reached a peak COI two to three days following vaccination before decaying. Further analysis of all the grayzone results within the 17 month study period (43 results out of 11,719 tests revealed that only 4 of 43 were the result of true HBV infection as verified by confirmatory testing. Conclusions Our study confirms that transient HBsAg positivity can occur in patients following HBV vaccination. The results suggest this positivity is unlikely to persist beyond 14 days

  8. Simultaneous identification of Trypanosoma cruzi surface and internal antigens reactive to different immunoglobulin classes (radio-immunoblotting)

    International Nuclear Information System (INIS)

    Stolf, A.M.S.; Umezawa, E.S.; Zingales, B.

    1990-01-01

    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 IgC specific antibodies. A different pattern of reactivity with acute Chagas disease patients sera was thus obtained. (author)

  9. Immunophenotyping of Waldenstroms macroglobulinemia cell lines reveals distinct patterns of surface antigen expression: potential biological and therapeutic implications.

    Directory of Open Access Journals (Sweden)

    Aneel Paulus

    Full Text Available Waldenströms macroglobulinemia (WM is a subtype of Non-Hodgkin's lymphoma in which the tumor cell population is markedly heterogeneous, consisting of immunoglobulin-M secreting B-lymphocytes, plasmacytoid lymphocytes and plasma cells. Due to rarity of disease and scarcity of reliable preclinical models, many facets of WM molecular and phenotypic architecture remain incompletely understood. Currently, there are 3 human WM cell lines that are routinely used in experimental studies, namely, BCWM.1, MWCL-1 and RPCI-WM1. During establishment of RPCI-WM1, we observed loss of the CD19 and CD20 antigens, which are typically present on WM cells. Intrigued by this observation and in an effort to better define the immunophenotypic makeup of this cell line, we conducted a more comprehensive analysis for the presence or absence of other cell surface antigens that are present on the RPCI-WM1 model, as well as those on the two other WM cell lines, BCWM.1 and MWCL-1. We examined expression of 65 extracellular and 4 intracellular antigens, comprising B-cell, plasma cell, T-cell, NK-cell, myeloid and hematopoietic stem cell surface markers by flow cytometry analysis. RPCI-WM1 cells demonstrated decreased expression of CD19, CD20, and CD23 with enhanced expression of CD28, CD38 and CD184, antigens that were differentially expressed on BCWM.1 and MWCL-1 cells. Due to increased expression of CD184/CXCR4 and CD38, RPCI-WM1 represents a valuable model in which to study the effects anti-CXCR4 or anti-CD38 targeted therapies that are actively being developed for treatment of hematologic cancers. Overall, differences in surface antigen expression across the 3 cell lines may reflect the tumor clone population predominant in the index patients, from whom the cell lines were developed. Our analysis defines the utility of the most commonly employed WM cell lines as based on their immunophenotype profiles, highlighting unique differences that can be further studied for

  10. Serum hepatitis B surface antigen and hepatitis B e antigen titers: disease phase influences correlation with viral load and intrahepatic hepatitis B virus markers.

    Science.gov (United States)

    Thompson, Alexander J V; Nguyen, Tin; Iser, David; Ayres, Anna; Jackson, Kathy; Littlejohn, Margaret; Slavin, John; Bowden, Scott; Gane, Edward J; Abbott, William; Lau, George K K; Lewin, Sharon R; Visvanathan, Kumar; Desmond, Paul V; Locarnini, Stephen A

    2010-06-01

    Although threshold levels for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) titers have recently been proposed to guide therapy for chronic hepatitis B (CHB), their relationship to circulating hepatitis B virus (HBV) DNA and intrahepatic HBV replicative intermediates, and the significance of emerging viral variants, remains unclear. We therefore tested the hypothesis that HBsAg and HBeAg titers may vary independently of viral replication in vivo. In all, 149 treatment-naïve CHB patients were recruited (HBeAg-positive, n = 71; HBeAg-negative, n = 78). Quantification of HBeAg and HBsAg was performed by enzyme immunoassay. Virological characterization included serum HBV DNA load, HBV genotype, basal core promoter (BCP)/precore (PC) sequence, and, in a subset (n = 44), measurement of intrahepatic covalently closed circular DNA (cccDNA) and total HBV DNA, as well as quantitative immunohistochemical (IHC) staining for HBsAg. In HBeAg-positive CHB, HBsAg was positively correlated with serum HBV DNA and intrahepatic cccDNA and total HBV DNA (r = 0.69, 0.71, 0.76, P < 0.01). HBeAg correlated with serum HBV DNA (r = 0.60, P < 0.0001), although emerging BCP/PC variants reduced HBeAg titer independent of viral replication. In HBeAg-negative CHB, HBsAg correlated poorly with serum HBV DNA (r = 0.28, P = 0.01) and did not correlate with intrahepatic cccDNA nor total HBV DNA. Quantitative IHC for hepatocyte HBsAg confirmed a relationship with viral replication only in HBeAg-positive patients. The correlation between quantitative HBsAg titer and serum and intrahepatic markers of HBV replication differs between patients with HBeAg-positive and HBeAg-negative CHB. HBeAg titers may fall independent of viral replication as HBeAg-defective variants emerge prior to HBeAg seroconversion. These findings provide new insights into viral pathogenesis and have practical implications for the use of quantitative serology as a clinical biomarker.

  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. 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

  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; 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.

  15. RIA Quick, AUSRIA II-125, AUSAB. Comparative study on isolated and simultaneous radioimmunoassay of hepatitis B surface antigen and antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Kselikova, M; Urbankova, J [Institut fuer Haematologie und Bluttransfusion, Prag (Czechoslovakia)

    1983-01-01

    The surface antigen of hepatitis B (HBsAg) and the antibodies against HBsAg can be determined separately by the radioimmunoassay (RIA) test kits AUSRIA II-125 and AUSAB, respectively. Using the test kit RIA Quick (IMMUNO, Wien) it is possible to perform both the determinations in one preparation simultaneously. The sensitivity of RIA Quick for HBsAg corresponds to that of AUSRIA II-125 and for HBsAB it is considerably lower than that of AUSAB. RIA Quick is of excellent technical design and is by a quarter cheaper than the kits for isolated determination of HBsAg and HBsAb.

  16. 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.

  17. 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.

  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. 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.

  20. Surface antigens and potential virulence factors from parasites detected by comparative genomics of perfect amino acid repeats

    Directory of Open Access Journals (Sweden)

    Adler Joël

    2007-12-01

    Full Text Available Abstract Background Many parasitic organisms, eukaryotes as well as bacteria, possess surface antigens with amino acid repeats. Making up the interface between host and pathogen such repetitive proteins may be virulence factors involved in immune evasion or cytoadherence. They find immunological applications in serodiagnostics and vaccine development. Here we use proteins which contain perfect repeats as a basis for comparative genomics between parasitic and free-living organisms. Results We have developed Reptile http://reptile.unibe.ch, a program for proteome-wide probabilistic description of perfect repeats in proteins. Parasite proteomes exhibited a large variance regarding the proportion of repeat-containing proteins. Interestingly, there was a good correlation between the percentage of highly repetitive proteins and mean protein length in parasite proteomes, but not at all in the proteomes of free-living eukaryotes. Reptile combined with programs for the prediction of transmembrane domains and GPI-anchoring resulted in an effective tool for in silico identification of potential surface antigens and virulence factors from parasites. Conclusion Systemic surveys for perfect amino acid repeats allowed basic comparisons between free-living and parasitic organisms that were directly applicable to predict proteins of serological and parasitological importance. An on-line tool is available at http://genomics.unibe.ch/dora.

  1. Characterization of the disassembly and reassembly of the HBV glycoprotein surface antigen, a pliable nanoparticle vaccine platform

    International Nuclear Information System (INIS)

    Gallagher, John R.; Torian, Udana; McCraw, Dustin M.; Harris, Audray K.

    2017-01-01

    While nanoparticle vaccine technology is gaining interest due to the success of vaccines like those for the human papillomavirus that is based on viral capsid nanoparticles, little information is available on the disassembly and reassembly of viral surface glycoprotein-based nanoparticles. One such particle is the hepatitis B virus surface antigen (sAg) that exists as nanoparticles. Here we show, using biochemical analysis coupled with electron microscopy, that sAg nanoparticle disassembly requires both reducing agent to disrupt intermolecular disulfide bonds, and detergent to disrupt hydrophobic interactions that stabilize the nanoparticle. Particles were otherwise resistant to salt and urea, suggesting the driving mechanism of particle formation involves hydrophobic interactions. We reassembled isolated sAg protein into nanoparticles by detergent removal and reassembly resulted in a wider distribution of particle diameters. Knowledge of these driving forces of nanoparticle assembly and stability should facilitate construction of epitope-displaying nanoparticles that can be used as immunogens in vaccines.

  2. Characterization of the disassembly and reassembly of the HBV glycoprotein surface antigen, a pliable nanoparticle vaccine platform

    Energy Technology Data Exchange (ETDEWEB)

    Gallagher, John R.; Torian, Udana; McCraw, Dustin M.; Harris, Audray K., E-mail: harrisau@mail.nih.gov

    2017-02-15

    While nanoparticle vaccine technology is gaining interest due to the success of vaccines like those for the human papillomavirus that is based on viral capsid nanoparticles, little information is available on the disassembly and reassembly of viral surface glycoprotein-based nanoparticles. One such particle is the hepatitis B virus surface antigen (sAg) that exists as nanoparticles. Here we show, using biochemical analysis coupled with electron microscopy, that sAg nanoparticle disassembly requires both reducing agent to disrupt intermolecular disulfide bonds, and detergent to disrupt hydrophobic interactions that stabilize the nanoparticle. Particles were otherwise resistant to salt and urea, suggesting the driving mechanism of particle formation involves hydrophobic interactions. We reassembled isolated sAg protein into nanoparticles by detergent removal and reassembly resulted in a wider distribution of particle diameters. Knowledge of these driving forces of nanoparticle assembly and stability should facilitate construction of epitope-displaying nanoparticles that can be used as immunogens in vaccines.

  3. STUDIES IN DYNAMICS OF APOPTOSIS-RELATED SURFACE ANTIGEN (CD95 EXPRESSION ON NEUTROPHILS FROM CERVICAL AND VAGINAL SECRETIONS IN WOMEN WITH CHLAMIDIA INFECTION

    Directory of Open Access Journals (Sweden)

    O. A. Giesinger

    2010-01-01

    Full Text Available CD95 (Fas/APO-1 antigen expression was studied on the surface of neutrophil granulocytes from cervical secretions. Sixty-five female patients with established Chlamydia infection were found to have an increased CD95+ antigen expression following basic therapy. CD95+ receptors on neutrophils in the patients with Chlamydia infection have been shown to return to normal levels following a combined magnetic laser treatment.

  4. Improved detection of equine antibodies against Sarcocystis neurona using polyvalent ELISAs based on the parasite SnSAG surface antigens.

    Science.gov (United States)

    Yeargan, Michelle R; Howe, Daniel K

    2011-02-28

    Equine protozoal myeloencephalitis (EPM) is a common neurologic disease of horses that is caused by the apicomplexan pathogen Sarcocystis neurona. To help improve serologic diagnosis of S. neurona infection, we have modified existing enzyme-linked immunosorbent assays (ELISAs) based on the immunogenic parasite surface antigens SnSAG2, SnSAG3, and SnSAG4 to make the assays polyvalent, thereby circumventing difficulties associated with parasite antigenic variants and diversity in equine immune responses. Two approaches were utilized to achieve polyvalence: (1) mixtures of the individual recombinant SnSAGs (rSnSAGs) were included in single ELISAs; (2) a collection of unique SnSAG chimeras that fused protein domains from different SnSAG surface antigens into a single recombinant protein were generated for use in the ELISAs. These new assays were assessed using a defined sample set of equine sera and cerebrospinal fluids (CSFs) that had been characterized by Western blot and/or were from confirmed EPM horses. While all of the polyvalent ELISAs performed relatively well, the highest sensitivity and specificity (100%/100%) were achieved with assays containing the rSnSAG4/2 chimera (Domain 1 of SnSAG4 fused to SnSAG2) or using a mixture of rSnSAG3 and rSnSAG4. The rSnSAG4 antigen alone and the rSnSAG4/3 chimera (Domain 1 of SnSAG4 fused to Domain 2 of SnSAG3) exhibited the next best accuracy at 95.2% sensitivity and 100% specificity. Binding ratios and percent positivity (PP) ratios, determined by comparing the mean values for positive versus negative samples, showed that the most advantageous signal to noise ratios were provided by rSnSAG4 and the rSnSAG4/3 chimera. Collectively, our results imply that a polyvalent ELISA based on SnSAG4 and SnSAG3, whether as a cocktail of two proteins or as a single chimeric protein, can give optimal results in serologic testing of serum or CSF for the presence of antibodies against S. neurona. The use of polyvalent SnSAG ELISAs will

  5. 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

  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. 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

  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

    The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) antigens play a major role in cytoadhesion of infected erythrocytes (IE), antigenic variation, and immunity to malaria. The current consensus on control of variant surface antigen expression is that only one PfEMP1 encoded by one var...

  9. 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

  10. Identification of sporozoite surface proteins and antigens of Eimeria nieschulzi (Apicomplexa)

    International Nuclear Information System (INIS)

    Tilley, M.; Upton, S.J.

    1990-01-01

    Sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotting, lectin binding, and 125 I surface labeling of sporozoites were used to probe sporozoites of the rat coccidian, Eimeria nieschulzi. Analysis of silver stained gels revealed greater than 50 bands. Surface iodination revealed about 14 well labeled, and about 10 weakly labeled but potential, surface proteins. The most heavily labeled surface proteins had molecular masses of 60, 53-54, 45, 28, 23-24, 17, 15, 14, 13, and 12 kD. Following electrophoresis and Western blotting, 2 of the 12 125I labeled lectin probes bound to two bands on the blots, which collectively indicated that two bands were glycosylated. Concanavalin A (ConA) specifically recognized a band at 53 kD, which may represent a surface glycoprotein, and a lectin derived from Osage orange (MPA) bound to a single band at 82-88 kD, that may also be a surface molecule. Immunoblotting using sera collected from rats inoculated orally with oocysts, as well as sera from mice hyperimmunized with sporozoites, revealed that many surface molecules appear to be immunogenic

  11. Variability in surface antigen expression on neuroblastoma cells as revealed by monoclonal antibodies

    International Nuclear Information System (INIS)

    Malpas, J.S.; Kemshead, J.T.; Pritchard, J.; Greaves, M.F.

    1982-01-01

    In treatment programmes for neuroblastoma involving autologous bone marrow transplantation, a problem exists in the identification of small numbers of metastatic tumour cells present in the marrow aspirates. Reinfusion of tumour cells along with normal bone marrow may reseed the tumour within a patient who has received high dose chemotherapy. Formalin-induced fluorescence in neuroblastoma is a possible diagnostic aid, but this method has no therapeutic potential. Other methods of detecting tumour relying on gross physiological changes in the patient are not suitable for diagnosis of minimal metastatic disease. As an immunological approach to the problem, rabbit antisera to neuroblastoma have been raised but these reagents suffer from low titre after absorption to make them specific. The authors have used the technique of somatic cell hybridisation to raise monoclonal antibodies which bind to neuroblastoma cells and not to normal haemopoietic progenitors. A panel of such reagents to demonstrate heterogeneity in antigen expression amongst metastatic neuroblastoma cells was employed in a radioimmunoassay as diagnostic aid for this problem. (Auth.)

  12. 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.

  13. 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...

  14. 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.

  15. 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...... response to gp95. These patients also showed an increase in IgG antibodies to gp95 and had microbiologically proven PCP. Prior to the development of the IgM response, IgG antibodies to gp95 were detectable in all 3 patients. Thus, HIV-infected patients with PCP seldom produce IgM antibodies to the major...

  16. [Diagnostic advantages of the test system "DS-EIA-HBsAg-0.01" for detection of HBV surface antigen].

    Science.gov (United States)

    Egorova, N I; Pyrenkova, I Iu; Igolkina, S N; Sharipova, I N; Puzyrev, V F; Obriadina, A P; Burkov, A N; Kornienko, N V; Fields, H A; Korovkin, A S; Shalunova, N V; Bektemirov, T A; Kuznetsov, K V; Koshcheeva, N A; Ulanova, T I

    2009-01-01

    The new highly sensitive test system "DS-EIA-HBsAg-0.01" (Priority Certificate No. 2006129019 of August 10, 2006) in detecting hepatitis B surface antigen (HBsAg) was assessed. The sensitivity of the test was estimated using the federal standards sample HBsAg 42-28-311-06, panels' samples Boston Biomedica Inc. (West Bridgewater, Mass, USA) and ZeptoMetrix Corp. (Buffalo, NY, USA). The findings have indicated that "DS-EIA-HBsAg-0.01" is equally effective in detecting different subtypes of HBsAg during a seroconversion period earlier than alternative assays. Along with its high analytical and diagnostic sensitivity, the system shows a high diagnostic specificity.

  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...... 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...

  18. Effects of oxygen and ethanol on recombinant yeast fermentation for hepatitis B virus surface antigen production: modeling and simulation studies.

    Science.gov (United States)

    Shi, Y; Ryu, D D; Yuan, W K

    1993-01-05

    A model was formulated to examine the competitive growth of two phenotypes (Leu(+) and Leu(-)) and the product formation with recombinant Saccharomyces cerevisiae strain DBY-745, which contains the shuttle vector pYGH3-16-s with the foreign gene HBsAg (hepatitis B virus surface antigen) as well as experimental fedbatch fermentation data. The important state variables and the process parameters evaluated include (1) the ratio of the plasmid-free cell concentration to the plasmid-containing cell concentration (rho = X(-)X(+)), (2) the expression of human hepatitis B surface antigen g (CH), (3) the glucose consumption (S), (4) the ethanol production (/), (5) the change of working volume (V) in the fermentor, (6) the different specific growth rates of two phenotype cells, and (7) the plasmid loss frequency coefficient (alpha ). These variables and other parameters were carefully defined, their correlations were studied, and a mathematical model using a set of nonlinear ordinary differential equations (ODEs) for fed-batch fermentation was then obtained based on the theoretical considerations and the experimental results. The extended Kalman filter (EKF) methods was applied for the best estimate of these variables based on the experimentally observable variables: rhoV, and g (CH). Each of these variable was affected by random measuring errors under the different operating conditions. Simulation results presented for verification of the model agreed with our observations and provided useful information relevant to the operation and the control of the fedbatch recombinant yeast fermentation. The method of predicting an optimal profile of the cell growth was also demonstrated under the different dissolved oxygen concentrations.

  19. Analysis of IgG with specificity for variant surface antigens expressed by placental Plasmodium falciparum isolates

    Directory of Open Access Journals (Sweden)

    Kremsner Peter G

    2004-07-01

    Full Text Available Abstract Background Pregnancy-associated malaria (PAM is caused by Plasmodium falciparum-infected erythrocytes that can sequester in placental intervillous space by expressing particular variant surface antigens (VSA that can mediate adhesion to chondroitin sulfate A (CSA in vitro. IgG antibodies with specificity for the VSA expressed by these parasites (VSAPAM are associated with protection from maternal anaemia, prematurity and low birth weight, which is the greatest risk factor for death in the first month of life. Methods In this study, the development of anti-VSAPAM antibodies in a group of 151 women who presented to the maternity ward of Albert Schweitzer Hospital in Lambaréné, Gabon for delivery was analysed using flow cytometry assays. Plasma samples from placenta infected primiparous women were also investigated for their capacity to inhibit parasite binding to CSA in vitro. Results In the study cohort, primiparous as well as secundiparous women had the greatest risk of infection at delivery as well as during pregnancy. Primiparous women with infected placentas at delivery showed higher levels of VSAPAM-specific IgG compared to women who had no malaria infections at delivery. Placental isolates of Gabonese and Senegalese origin tested on plasma samples from Gabon showed parity dependency and gender specificity patterns. There was a significant correlation of plasma reactivity as measured by flow cytometry between different placental isolates. In the plasma of infected primiparous women, VSAPAM-specific IgG measured by flow cytometry could be correlated with anti-adhesion antibodies measured by the inhibition of CSA binding. Conclusion Recognition of placental parasites shows a parity- and sex- dependent pattern, like that previously observed in laboratory strains selected to bind to CSA. Placental infections at delivery in primiparous women appear to be sufficient to induce functional antibodies which can both recognize the surface of

  20. Influence of polymer architecture on antigens camouflage, CD47 protection and complement mediated lysis of surface grafted red blood cells.

    Science.gov (United States)

    Chapanian, Rafi; Constantinescu, Iren; Rossi, Nicholas A A; Medvedev, Nadia; Brooks, Donald E; Scott, Mark D; Kizhakkedathu, Jayachandran N

    2012-11-01

    Hyperbranched polyglycerol (HPG) and polyethylene glycol (PEG) polymers with similar hydrodynamic sizes in solution were grafted to red blood cells (RBCs) to investigate the impact of polymer architecture on the cell structure and function. The hydrodynamic sizes of polymers were calculated from the diffusion coefficients measured by pulsed field gradient NMR. The hydration of the HPG and PEG was determined by differential scanning calorimetry analyses. RBCs grafted with linear PEG had different properties compared to the compact HPG grafted RBCs. HPG grafted RBCs showed much higher electrophoretic mobility values than PEG grafted RBCs at similar grafting concentrations and hydrodynamic sizes indicating differences in the structure of the polymer exclusion layer on the cell surface. PEG grafting impacted the deformation properties of the membrane to a greater degree than HPG. The complement mediated lysis of the grafted RBCs was dependent on the type of polymer, grafting concentration and molecular size of grafted chains. At higher molecular weights and graft concentrations both HPG and PEG triggered complement activation. The magnitude of activation was higher with HPG possibly due to the presence of many hydroxyl groups per molecule. HPG grafted RBCs showed significantly higher levels of CD47 self-protein accessibility than PEG grafted RBCs at all grafting concentrations and molecular sizes. PEG grafted polymers provided, in general, a better shielding and protection to ABO and minor antigens from antibody recognition than HPG polymers, however, the compact HPGs provided greater protection of certain antigens on the RBC surface. Our data showed that HPG 20 kDa and HPG 60 kDa grafted RBCs exhibited properties that are more comparable to the native RBC than PEG 5 kDa and PEG 10 kDa grafted RBCs of comparable hydrodynamic sizes. The study shows that small compact polymers such as HPG 20 kDa have a greater potential in the generation of functional RBC for therapeutic

  1. Temporal expression and localization patterns of variant surface antigens in clinical Plasmodium falciparum isolates during erythrocyte schizogony.

    Directory of Open Access Journals (Sweden)

    Anna Bachmann

    Full Text Available Avoidance of antibody-mediated immune recognition allows parasites to establish chronic infections and enhances opportunities for transmission. The human malaria parasite Plasmodium falciparum possesses a number of multi-copy gene families, including var, rif, stevor and pfmc-2tm, which encode variant antigens believed to be expressed on the surfaces of infected erythrocytes. However, most studies of these antigens are based on in vitro analyses of culture-adapted isolates, most commonly the laboratory strain 3D7, and thus may not be representative of the unique challenges encountered by P. falciparum in the human host. To investigate the expression of the var, rif-A, rif-B, stevor and pfmc-2tm family genes under conditions that mimic more closely the natural course of infection, ex vivo clinical P. falciparum isolates were analyzed using a novel quantitative real-time PCR approach. Expression patterns in the clinical isolates at various time points during the first intraerythrocytic developmental cycle in vitro were compared to those of strain 3D7. In the clinical isolates, in contrast to strain 3D7, there was a peak of expression of the multi-copy gene families rif-A, stevor and pfmc-2tm at the young ring stage, in addition to the already known expression peak in trophozoites. Furthermore, most of the variant surface antigen families were overexpressed in the clinical isolates relative to 3D7, with the exception of the pfmc-2tm family, expression of which was higher in 3D7 parasites. Immunofluorescence analyses performed in parallel revealed two stage-dependent localization patterns of RIFIN, STEVOR and PfMC-2TM. Proteins were exported into the infected erythrocyte at the young trophozoite stage, whereas they remained inside the parasite membrane during schizont stage and were subsequently observed in different compartments in the merozoite. These results reveal a complex pattern of expression of P. falciparum multi-copy gene families during

  2. Anti-IL-5 attenuates activation and surface density of β2-integrins on circulating eosinophils after segmental antigen challenge

    Science.gov (United States)

    Johansson, Mats W.; Gunderson, Kristin A.; Kelly, Elizabeth A. B.; Denlinger, Loren C.; Jarjour, Nizar N.; Mosher, Deane F.

    2013-01-01

    Background IL-5 activates αMβ2 integrin on blood eosinophils in vitro. Eosinophils in bronchoalveolar lavage (BAL) following segmental antigen challenge have activated β2-integrins. Objective To identify roles for IL-5 in regulating human eosinophil integrins in vivo. Methods Blood and BAL eosinophils were analyzed by flow cytometry in ten subjects with allergic asthma who underwent a segmental antigen challenge protocol before and after anti-IL-5 administration. Results Blood eosinophil reactivity with monoclonal antibody (mAb) KIM-127, which recognizes partially activated β2-integrins, was decreased after anti-IL-5. Before anti-IL-5, surface densities of blood eosinophil β2, αM, and αL integrin subunits increased modestly post-challenge. After anti-IL-5, such increases did not occur. Before or after anti-IL-5, surface densities of β2,αM, αL, and αD and reactivity with KIM-127 and mAb CBRM1/5, which recognizes high-activity αMβ2, were similarly high on BAL eosinophils 48 h post-challenge. Density and activation state of β1-integrins on blood and BAL eosinophils were not impacted by anti-IL-5, even though anti-IL-5 ablated a modest post-challenge increase on blood or BAL eosinophils of P-selectin glycoprotein ligand-1 (PSGL-1), a receptor for P-selectin that causes activation of β1-integrins. Forward scatter of blood eosinophils post-challenge was less heterogeneous and on the average decreased after anti-IL-5; however, anti-IL-5 had no effect on the decreased forward scatter of eosinophils in post-challenge BAL compared to eosinophils in blood. Blood eosinophil KIM-127 reactivity at the time of challenge correlated with the percentage of eosinophils in BAL post-challenge. Conclusion and Clinical Relevance IL-5 supports a heterogeneous population of circulating eosinophils with partially activated β2-integrins and is responsible for upregulation of β2-integrins and PSGL-1 on circulating eosinophils following segmental antigen challenge but has

  3. Comparison of two solid-phase radioimmunoassay systems and a reverse passive haemagglutination test for the detection of hepatitis B surface antigen

    International Nuclear Information System (INIS)

    Hui, Z.; Coulepis, A.G.; Gust, I.D.

    1982-01-01

    The sensitivity and specificity of two commercially available radioimmunosay tests (Austria II-125, Abbott Laboratories; and International CIS, Commissariat Alenergie Atomique-Oris Laboratoire des Produits Biomedicaux) and a reverse passive haemagglutination test (Hepatest, Wellcome) for detection of hepatitis B surface antigen were evaluated using the Australian hepatitis B reference panel of 25 sera, and a panel of 257 sera collected from patients with acute hepatitis B, chronic carriers of hepatitis B surface antigen and two populations in which hepatitis B virus infection is known to be endemic. The three techniques were found to be generally comparable in sensitivity and specificity. The advantages and disadvantages of each method are discussed

  4. 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).

  5. 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)

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

    International Nuclear Information System (INIS)

    Michelin, S.; Gallegos, C.E.; Dubner, D.; Favier, B.; Carosella, E.D.

    2009-01-01

    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 γ-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 γ-irradiation decreases HLA-G1 surface levels by enhancing the proteolytic cleavage of this molecule. (authors)

  7. 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

  8. 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

    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...... chimeras in an attenuated Salmonella strain....

  9. Committed T lymphocyte stem cells of rats. Characterization by surface W3/13 antigen and radiosensitivity

    International Nuclear Information System (INIS)

    Dyer, M.J.; Hunt, S.V.

    1981-01-01

    The existence of stem cells committed to the T lymphoid lineage was deduced from studying how rat T and B stem cells differ in their expression of membrane W3/13 antigen and in their susceptibility in vivo to gamma irradiation. Stem cell activity of rat bone marrow and fetal liver was measured in long-term radiation chimeras using B and T cell alloantigenic surface markers to identify the progeny of donor cells. Monoclonal mouse anti-rat thymocyte antibody W3/13 labeled approximately 40% of fetal liver cells and 60-70% of young rat bone marrow cells (40% brightly, 25% dimly). Bright, dim, and negative cells were separated on a fluorescence-activated cell sorter. All B and T lymphoid stem cells in fetal liver were W3/13 bright, as were B lymphoid stem cells in bone marrow. W3/13 dim bone marrow had over half the T cell repopulating activity of unseparated marrow but gave virtually no B cell repopulation. In further experiments, the radiosensitivity of endogenous B and T lymphoid stem cells was determined by exposing host rats to between 4.5 and 10 Gy of gamma irradiation before repopulation with genetically marked marrow. The results depended on whether chimerism was assayed before day 50 or after day 100. At early times, a radioresistant T stem cell was indicated, whose activity waned later. Thus committed T stem cells of rats carry moderate amounts of W3/13 antigen and are more radioresistant but less permanently chimeragenic than the stem cells that regenerate B lymphocytes

  10. 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.)

  11. 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 infect...

  12. Determinants of variant surface antigen antibody response in severe Plasmodium falciparum malaria in an area of low and unstable malaria transmission

    DEFF Research Database (Denmark)

    A-Elgadir, T M E; Theander, T G; Elghazali, G

    2006-01-01

    The variant surface antigens (VSA) of infected erythrocytes are important pathogenic markers, a set of variants (VSA(SM)), were assumed to be associated with severe malaria (SM), while SM constitutes clinically diverse forms, such as, severe malarial anemia (SMA) and cerebral malaria (CM). This s...

  13. 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....

  14. 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...

  15. 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.

  16. 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...

  17. The herpes virus Fc receptor gE-gI mediates antibody bipolar bridging to clear viral antigens from the cell surface.

    Directory of Open Access Journals (Sweden)

    Blaise Ndjamen

    2014-03-01

    Full Text Available The Herpes Simplex Virus 1 (HSV-1 glycoprotein gE-gI is a transmembrane Fc receptor found on the surface of infected cells and virions that binds human immunoglobulin G (hIgG. gE-gI can also participate in antibody bipolar bridging (ABB, a process by which the antigen-binding fragments (Fabs of the IgG bind a viral antigen while the Fc binds to gE-gI. IgG Fc binds gE-gI at basic, but not acidic, pH, suggesting that IgG bound at extracellular pH by cell surface gE-gI would dissociate and be degraded in acidic endosomes/lysosomes if endocytosed. The fate of viral antigens associated with gE-gI-bound IgG had been unknown: they could remain at the cell surface or be endocytosed with IgG. Here, we developed an in vitro model system for ABB and investigated the trafficking of ABB complexes using 4-D confocal fluorescence imaging of ABB complexes with transferrin or epidermal growth factor, well-characterized intracellular trafficking markers. Our data showed that cells expressing gE-gI and the viral antigen HSV-1 gD endocytosed anti-gD IgG and gD in a gE-gI-dependent process, resulting in lysosomal localization. These results suggest that gE-gI can mediate clearance of infected cell surfaces of anti-viral host IgG and viral antigens to evade IgG-mediated responses, representing a general mechanism for viral Fc receptors in immune evasion and viral pathogenesis.

  18. [Prevalence of hepatitis B surface antigen and its associated factors in Senegalese military personnel sent on mission to Darfur].

    Science.gov (United States)

    Diop, Moustapha; Diouf, Assane; Seck, Said Malaobé; Lo, Gora; Ka, Daye; Massaly, Aminata; Dieye, Alassane; Fall, Ndeye Maguette; Cisse-Diallo, Viviane Marie Pierre; Diallo-Mbaye, Khardiata; Lakhe, Ndèye Aissatou; Fortes-Déguénonvo, Louise; Ndour, Cheikh Tidiane; Soumaré, Maserigne; Seydi, Moussa

    2017-01-01

    In Senegal, 85% of the adult population have been exposed to the hepatitis B virus and about 11% of them are chronic surface antigen (HBsAg) carriers. This infection is poorly documented among Senegalese Armed Forces. The aim of this study was to assess the prevalence of HBsAg in Senegalese military personnel on mission to Darfur (Sudan) and to identify its associated factors. We conducted a cross-sectional study among Senegalese military personnel stationed in Darfur from 1 July 2014 to 31 July 2014. HBsAg test was performed on serum of participants using immunochromatographic method. The search for associated factors was carried out using multivariate logistic regression. Our study included 169 male military personnel. The average age was 36.6 ± 9.5 years. A history of familial chronic liver disease, blood exposure and sexual exposure were found in 12.4%, 24.9% and 45.6% of the study population respectively. HBsAg was found in 24 participants [14.2% (CI 95% = 8.9-19.5)]. After adjusting for potential confounding factors, age (OR = 0.9 CI 95% = 0.9-1.0), university level (OR = 9.5 CI 95% = 1.3 - 67 , 1>) and sexual exposure (OR = 3.3 <; CI 95% = 1.0 - 10.3) were independently associated with hepatitis B. Our study shows high prevalence of HBsAg and underlines the need for further evaluation of hepatitis B in this population.

  19. 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.

  20. Antibody to hepatitis B surface antigen among employees in the National Hospital, Oslo, Norway: a prevalence study.

    Science.gov (United States)

    Hovig, B; Rollag, H; Dahl, O

    1985-07-01

    During the last decade, several studies of serologic markers of hepatitis B virus infections in hospital personnel have demonstrated an increased prevalence of antibodies to hepatitis B virus (anti-HB) compared with the general population. Norway has a very low incidence rate of hepatitis B as seen on a global scale, and this study was performed to evaluate the infection risk by hospital workers in such environments. The employees, 2,546 (94.7% of the population), in the 800-bed National Hospital in Oslo were tested for antibody to hepatitis B surface antigen (anti-HBs) in serum. Five per cent (128 persons) were anti-HBs-positive; this was only slightly higher than that in the general Norwegian population. Male employees were more often positive than females (7.0% vs. 4.4%). Staff more than 50 years of age or with 16 or more years of employment in the health services had a rate twice as high as the rest of the employees. Staff in the porter services (mostly men) had a higher rate than others, whereas the rates in the different professional groups showed no statistical differences. Contrary to many other studies, significant differences in prevalence according to frequency of patient contact or blood handling were not found.

  1. 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.

  2. 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.

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

    International Nuclear Information System (INIS)

    Blokhina, Elena A.; Kuprianov, Victor V.; Stepanova, Ludmila A.; Tsybalova, Ludmila M.; Kiselev, Oleg I.; Ravin, Nikolai V.; Skryabin, Konstantin G.

    2013-01-01

    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.

  4. The crystal structure of Haloferax volcanii proliferating cell nuclear antigen reveals unique surface charge characteristics due to halophilic adaptation

    Directory of Open Access Journals (Sweden)

    Morroll Shaun

    2009-08-01

    Full Text Available Abstract Background The high intracellular salt concentration required to maintain a halophilic lifestyle poses challenges to haloarchaeal proteins that must stay soluble, stable and functional in this extreme environment. Proliferating cell nuclear antigen (PCNA is a fundamental protein involved in maintaining genome integrity, with roles in both DNA replication and repair. To investigate the halophilic adaptation of such a key protein we have crystallised and solved the structure of Haloferax volcanii PCNA (HvPCNA to a resolution of 2.0 Å. Results The overall architecture of HvPCNA is very similar to other known PCNAs, which are highly structurally conserved. Three commonly observed adaptations in halophilic proteins are higher surface acidity, bound ions and increased numbers of intermolecular ion pairs (in oligomeric proteins. HvPCNA possesses the former two adaptations but not the latter, despite functioning as a homotrimer. Strikingly, the positive surface charge considered key to PCNA's role as a sliding clamp is dramatically reduced in the halophilic protein. Instead, bound cations within the solvation shell of HvPCNA may permit sliding along negatively charged DNA by reducing electrostatic repulsion effects. Conclusion The extent to which individual proteins adapt to halophilic conditions varies, presumably due to their diverse characteristics and roles within the cell. The number of ion pairs observed in the HvPCNA monomer-monomer interface was unexpectedly low. This may reflect the fact that the trimer is intrinsically stable over a wide range of salt concentrations and therefore additional modifications for trimer maintenance in high salt conditions are not required. Halophilic proteins frequently bind anions and cations and in HvPCNA cation binding may compensate for the remarkable reduction in positive charge in the pore region, to facilitate functional interactions with DNA. In this way, HvPCNA may harness its environment as

  5. The crystal structure of Haloferax volcanii proliferating cell nuclear antigen reveals unique surface charge characteristics due to halophilic adaptation

    Science.gov (United States)

    Winter, Jody A; Christofi, Panayiotis; Morroll, Shaun; Bunting, Karen A

    2009-01-01

    Background The high intracellular salt concentration required to maintain a halophilic lifestyle poses challenges to haloarchaeal proteins that must stay soluble, stable and functional in this extreme environment. Proliferating cell nuclear antigen (PCNA) is a fundamental protein involved in maintaining genome integrity, with roles in both DNA replication and repair. To investigate the halophilic adaptation of such a key protein we have crystallised and solved the structure of Haloferax volcanii PCNA (HvPCNA) to a resolution of 2.0 Å. Results The overall architecture of HvPCNA is very similar to other known PCNAs, which are highly structurally conserved. Three commonly observed adaptations in halophilic proteins are higher surface acidity, bound ions and increased numbers of intermolecular ion pairs (in oligomeric proteins). HvPCNA possesses the former two adaptations but not the latter, despite functioning as a homotrimer. Strikingly, the positive surface charge considered key to PCNA's role as a sliding clamp is dramatically reduced in the halophilic protein. Instead, bound cations within the solvation shell of HvPCNA may permit sliding along negatively charged DNA by reducing electrostatic repulsion effects. Conclusion The extent to which individual proteins adapt to halophilic conditions varies, presumably due to their diverse characteristics and roles within the cell. The number of ion pairs observed in the HvPCNA monomer-monomer interface was unexpectedly low. This may reflect the fact that the trimer is intrinsically stable over a wide range of salt concentrations and therefore additional modifications for trimer maintenance in high salt conditions are not required. Halophilic proteins frequently bind anions and cations and in HvPCNA cation binding may compensate for the remarkable reduction in positive charge in the pore region, to facilitate functional interactions with DNA. In this way, HvPCNA may harness its environment as opposed to simply surviving in

  6. 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

  7. 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

  8. 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.

  9. Hepatitis B surface antigen (HBsAg) and core antigen (HBcAg) combine CpG oligodeoxynucletides as a novel therapeutic vaccine for chronic hepatitis B infection.

    Science.gov (United States)

    Li, Jianqiang; Ge, Jun; Ren, Sulin; Zhou, Tong; Sun, Ying; Sun, Honglin; Gu, Yue; Huang, Hongying; Xu, Zhenxing; Chen, Xiaoxiao; Xu, Xiaowei; Zhuang, Xiaoqian; Song, Cuiling; Jia, Fangmiao; Xu, Aiguo; Yin, Xiaojin; Du, Sean X

    2015-08-20

    Hepatitis B virus infection is a non-cytopathic hepatotropic virus which can lead to chronic liver disease and hepatocellular carcinoma. Traditional therapies fail to provide sustained control of viral replication and liver damage in most patients. As an alternative strategy, immunotherapeutic approaches have shown promising efficacy in the treatment of chronic hepatitis B patients. Here, we investigated the efficacy of a novel therapeutic vaccine formulation consisting of two HBV antigens, HBsAg and HBcAg, and CpG adjuvant. This vaccine formulation elicits forceful humoral responses directed against HBsAg/HBcAg, and promotes a Th1/Th2 balance response against HBsAg and a Th1-biased response against HBcAg in both C57BL/6 and HBV transgenic mice. Vigorous cellular immune response was also detected in HBV transgenic mice, for a significantly higher number of HBs/HBc-specific IFN-γ secreting CD4+ and CD8+ T cells was generated. Moreover, vaccinated mice elicited significantly intense in vivo CTL attack, reduced serum HBsAg level without causing liver damage in HBV transgenic mice. In summary, this study demonstrates a novel therapeutic vaccine with the potential to elicit vigorous humoral and cellular response, overcoming tolerance in HBV transgenic mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Genetic variation of hepatitis B surface antigen among acute and chronic hepatitis B virus infections in The Netherlands.

    Science.gov (United States)

    Cremer, Jeroen; Hofstraat, Sanne H I; van Heiningen, Francoise; Veldhuijzen, Irene K; van Benthem, Birgit H B; Benschop, Kimberley S M

    2018-05-24

    Genetic variation within hepatitis B surface antigen (HBsAg), in particular within the major hydrophobic region (MHR), is related to immune/vaccine and test failures and can have a significant impact on the vaccination and diagnosis of acute infection. This study shows, for the first time, variation among acute cases and compares the amino acid variation within the HBsAg between acute and chronic infections. We analyzed the virus isolated from 1231 acute and 585 chronic cases reported to an anonymized public health surveillance database between 2004 and 2014 in The Netherlands. HBsAg analysis revealed the circulation of 6 genotypes (Gt); GtA was the dominant genotype followed by GtD among both acute (68.2% and 17.4%, respectively) and chronic (34.9% and 34.2%, respectively) cases. Variation was the highest among chronic strains compared to that among acute strains. Both acute and chronic GtD showed the highest variation compared to that of other genotypes (P < .01). Substitutions within the MHR were found in 8.5% of the acute strains and 18.6% of the chronic strains. Specific MHR substitutions described to have an impact on vaccine/immune escape and/or HBsAg test failure were found among 4.1% of the acute strains and 7.0% of the chronic strains. In conclusion, we show a high variation of HBsAg among acute and chronic hepatitis B virus-infected cases in The Netherlands, in particular among those infected with GtD, and compare, for the first time, variation in frequencies between acute and chronic cases. Additional studies on the impact of these variations on vaccination and test failure need to be conducted, as well as whether HBsAg false-negative variants have been missed. © 2018 The Authors. Journal of Medical Virology Published by Wiley Periodicals, Inc.

  11. Hepatitis B virus surface antigen impairs myeloid dendritic cell function: a possible immune escape mechanism of hepatitis B virus

    Science.gov (United States)

    Op den Brouw, Marjoleine L; Binda, Rekha S; van Roosmalen, Mark H; Protzer, Ulrike; Janssen, Harry L A; van der Molen, Renate G; Woltman, Andrea M

    2009-01-01

    Chronic hepatitis B virus (HBV) infection is the result of an inadequate immune response towards the virus. Myeloid dendritic cells (mDC) of patients with chronic HBV are impaired in their maturation and function, resulting in more tolerogenic rather than immunogenic responses, which may contribute to viral persistence. The mechanism responsible for altered mDC function remains unclear. The HBV-infected patients display large amounts of HBV particles and viral proteins in their circulation, especially the surface antigen HBsAg, which allows multiple interactions between the virus, its viral proteins and DC. To assess whether HBV directly influences mDC function, the effects of HBV and HBsAg on human mDC maturation and function were investigated in vitro. As already described for internalization of HBV by DC, the present study shows that peripheral blood-derived mDC of healthy controls also actively take up HBsAg in a time-dependent manner. Cytokine-induced maturation in the presence of HBV or HBsAg resulted in a significantly more tolerogenic mDC phenotype as demonstrated by a diminished up-regulation of costimulatory molecules and a decreased T-cell stimulatory capacity, as assessed by T-cell proliferation and interferon-γ production. In addition, the presence of HBV significantly reduced interleukin-12 production by mDC. These results show that both HBV particles and purified HBsAg have an immune modulatory capacity and may directly contribute to the dysfunction of mDC in patients with chronic HBV. The direct immune regulatory effect of HBV and circulating HBsAg particles on the function of DC can be considered as part of the mechanism by which HBV escapes immunity. PMID:18624732

  12. 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.

  13. 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.

  14. 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....

  15. 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

  16. 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.

  17. Differential presentation of endogenous and exogenous hepatitis B surface antigens influences priming of CD8(+) T cells in an epitope-specific manner.

    Science.gov (United States)

    Riedl, Petra; Reiser, Michael; Stifter, Katja; Krieger, Jana; Schirmbeck, Reinhold

    2014-07-01

    Little is known about whether presentation of endogenous and exogenous hepatitis B virus (HBV) surface antigens on APCs targeted by vaccination and/or virus-harboring hepatocytes influences de novo priming of CD8(+) T cells. We showed that surface antigen-expressing transfectants exclusively display a K(b) /S190 epitope, whereas cells pulsed with recombinant surface particles (rSPs) exclusively present a K(b) /S208 epitope to CD8(+) T cells. The differential presentation of these epitopes largely reflects the selective, but not exclusive, priming of K(b) /S190- and K(b) /S208-specific T cells in C57BL/6 mice by endogenous/DNA- or exogenous/protein-based vaccines, respectively. Silencing the K(b) /S190 epitope (K(b) /S190V194F ) in antigen-expressing vectors rescued the presentation of the K(b) /S208 epitope in stable transfectants and significantly enhanced priming of K(b) /S208-specific T cells in C57BL/6 mice. A K(b) /S190-mediated immunodominance operating in surface antigen-expressing cells, but not in rSP-pulsed cells, led to an efficient suppression in the presentation of the K(b) /S208 epitope and a consequent decrease in the priming of K(b) /S208-specific T cells. This K(b) /S190-mediated immunodominance also operated in 1.4HBV-S(mut) transgenic (tg) hepatocytes selectively expressing endogenous surface antigens and allowed priming of K(b) /S208- but not K(b) /S190-specific T cells in 1.4HBV-S(mut) tg mice. However, IFN-γ(+) K(b) /S208-specific T cells could not inhibit HBV replication in the liver of 1.4HBV-S(mut) tg mice. These results have practical implications for the design of T-cell-stimulating therapeutic vaccines. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

    Matos, Carlos António; Gonçalves, Luiz Ricardo; Alvarez, Dasiel Obregón; Freschi, Carla Roberta; Silva, Jenevaldo Barbosa da; Val-Moraes, Silvana Pompeia; Mendes, Natalia Serra; André, Marcos Rogério; Machado, Rosangela Zacarias

    2017-01-01

    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.

  19. Cost-effectiveness of quantitative hepatitis B virus surface antigen testing in pregnancy in predicting vertical transmission risk.

    Science.gov (United States)

    Samadi Kochaksaraei, Golasa; Congly, Stephen E; Matwiy, Trudy; Castillo, Eliana; Martin, Steven R; Charlton, Carmen L; Coffin, Carla S

    2016-11-01

    Vertical transmission of hepatitis B virus (HBV) can occur despite immunoprophylaxis in mothers with high HBV DNA levels (>5-7 log 10 IU/ml). Quantitative hepatitis B surface antigen (qHBsAg) testing could be used as a surrogate marker to identify high viral load carriers, but there is limited data in pregnancy. We conducted a prospective observational study to determine the cost-effectiveness and utility of qHBsAg as a valid surrogate marker of HBV DNA. Pregnant patients with chronic hepatitis B were recruited from a tertiary referral centre. HBV DNA levels and qHBsAg were assessed in the second to third trimester. Statistical analysis was performed by Spearman's rank correlation and student's t-test. The cost-effectiveness of qHBsAg as compared to HBV DNA testing was calculated. Ninety nine women with 103 pregnancies, median age 32 years, 65% Asian, 23% African and 12% other [Hispanic, Caucasian] were enrolled. Overall, 23% (23/99) were HBV e Ag (HBeAg)-positive. A significant correlation between qHBsAg and HBV DNA levels was noted in HBeAg-positive patients (r = 0.79, P < 0.05) but not in HBeAg-negative patients (r = 0.17, P = 0.06). In receiver operating characteristic analysis, the optimal qHBsAg cut-off values for predicting maternal viraemia associated with immunoprophylaxis failure (i.e., HBV DNA ≥7 log 10 IU/ml) was 4.3 log 10 IU/ml (accuracy 98.7%, sensitivity 94.7%, specificity 94.4%) (95% CI, 97-100%, P < 0.05). Use of HBV DNA as compared to qHBsAg costs approximately $20 000 more per infection prevented. In resource poor regions, qHBsAg could be used as a more cost-effective marker for high maternal viraemia, and indicate when anti-HBV nucleos/tide analogue therapy should be used to prevent HBV immunoprophylaxis failure. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Diagnostic accuracy of tests to detect hepatitis B surface antigen: a systematic review of the literature and meta-analysis

    Directory of Open Access Journals (Sweden)

    Ali Amini

    2017-11-01

    Full Text Available Abstract Background Chronic Hepatitis B Virus (HBV infection is characterised by the persistence of hepatitis B surface antigen (HBsAg. Expanding HBV diagnosis and treatment programmes into low resource settings will require high quality but inexpensive rapid diagnostic tests (RDTs in addition to laboratory-based enzyme immunoassays (EIAs to detect HBsAg. The purpose of this review is to assess the clinical accuracy of available diagnostic tests to detect HBsAg to inform recommendations on testing strategies in 2017 WHO hepatitis testing guidelines. Methods The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA guidelines using 9 databases. Two reviewers independently extracted data according to a pre-specified plan and evaluated study quality. Meta-analysis was performed. HBsAg diagnostic accuracy of rapid diagnostic tests (RDTs was compared to enzyme immunoassay (EIA and nucleic-acid test (NAT reference standards. Subanalyses were performed to determine accuracy among brands, HIV-status and specimen type. Results Of the 40 studies that met the inclusion criteria, 33 compared RDTs and/or EIAs against EIAs and 7 against NATs as reference standards. Thirty studies assessed diagnostic accuracy of 33 brands of RDTs in 23,716 individuals from 23 countries using EIA as the reference standard. The pooled sensitivity and specificity were 90.0% (95% CI: 89.1, 90.8 and 99.5% (95% CI: 99.4, 99.5 respectively, but accuracy varied widely among brands. Accuracy did not differ significantly whether serum, plasma, venous or capillary whole blood was used. Pooled sensitivity of RDTs in 5 studies of HIV-positive persons was lower at 72.3% (95% CI: 67.9, 76.4 compared to that in HIV-negative persons, but specificity remained high. Five studies evaluated 8 EIAs against a chemiluminescence immunoassay reference standard with a pooled sensitivity and specificity of 88.9% (95% CI: 87.0, 90.6 and

  1. Three-dimensional structure of a glycosylated cell surface antigen from D. discoideum: a primordial adhesion motif

    International Nuclear Information System (INIS)

    Mabbutt, B.C.; Swarbrick, J.; Cubeddu, L.; Hill, A.

    1999-01-01

    Full text: We have determined the solution structure of pre-spore specific antigen (PsA), a predominant cell surface glycoprotein from the slime mould Dictyostelium discoideum. The structure and function of this protein suggests that it serves as a molecular signal for multicellular organisation, and that it may also be an adhesion motif mediating direct cell-cell contact. PsA consists of a 90-residue N-terminal globular domain tethered to the cell membrane via a heavily O-glycosylated stalk and a GPI anchor. No homologous sequences have been identified for the N-terminal domain. At Macquarie University, the D. discoideum organism has been well developed as a eukaryotic expression host for glycosylated proteins. For NMR, we have engineered a soluble form of PsA (residues 1-122) containing the globular 'head' and the glycopeptide linker. 15 N- and 15 N/ 13 C-labelled PsA was generated in this organism via a protocol that is readily adaptable for the cost-effective production of milligram quantities of other isotopically labelled recombinant proteins. Using 3D heteronuclear NMR, we have solved the three-dimensional structure of the PsA glycoprotein. It defines an eight stranded β-sandwich of five-on-three topology in a unique arrangement. A long loop is constrained by a cis proline residue and a disulphide bond to form an opening across one end of the sandwich, exposing portions of the hydrophobic interior. We postulate that this distortion of the sandwich fold structures a binding site. Structural and dynamics information was also obtained concerning the intact glycopeptide linker of the protein, which comprises a repeating P-T-V-T motif. In our recombinant form, each Thr residue is modified by a single GlcNAc sugar. This simple structure yields interpretable NMR spectra, which show the glycosylated linker to be in extended conformation, and undergoing distinctly different mobility from the globular domain. These same sugar residues provide an ideal attachment

  2. The SnSAG merozoite surface antigens of Sarcocystis neurona are expressed differentially during the bradyzoite and sporozoite life cycle stages.

    Science.gov (United States)

    Gautam, A; Dubey, J P; Saville, W J; Howe, D K

    2011-12-29

    Sarcocystis neurona is a two-host coccidian parasite whose complex life cycle progresses through multiple developmental stages differing at morphological and molecular levels. The S. neurona merozoite surface is covered by multiple, related glycosylphosphatidylinositol-linked proteins, which are orthologous to the surface antigen (SAG)/SAG1-related sequence (SRS) gene family of Toxoplasma gondii. Expression of the SAG/SRS proteins in T. gondii and another related parasite Neospora caninum is life-cycle stage specific and seems necessary for parasite transmission and persistence of infection. In the present study, the expression of S. neurona merozoite surface antigens (SnSAGs) was evaluated in the sporozoite and bradyzoite stages. Western blot analysis was used to compare SnSAG expression in merozoites versus sporozoites, while immunocytochemistry was performed to examine expression of the SnSAGs in merozoites versus bradyzoites. These analyses revealed that SnSAG2, SnSAG3 and SnSAG4 are expressed in sporozoites, while SnSAG5 was appeared to be downregulated in this life cycle stage. In S. neurona bradyzoites, it was found that SnSAG2, SnSAG3, SnSAG4 and SnSAG5 were either absent or expression was greatly reduced. As shown for T. gondii, stage-specific expression of the SnSAGs may be important for the parasite to progress through its developmental stages and complete its life cycle successfully. Thus, it is possible that the SAG switching mechanism by these parasites could be exploited as a point of intervention. As well, the alterations in surface antigen expression during different life cycle stages may need to be considered when designing prospective approaches for protective vaccination. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. 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.

  4. Induction of anti-HBs in HB vaccine nonresponders in vivo by hepatitis B surface antigen-pulsed blood dendritic cells.

    Science.gov (United States)

    Fazle Akbar, Sk Md; Furukawa, Shinya; Yoshida, Osamu; Hiasa, Yoichi; Horiike, Norio; Onji, Morikazu

    2007-07-01

    Antigen-pulsed dendritic cells (DCs) are now used for treatment of patients with cancers, however, the efficacy of these DCs has never been evaluated for prophylactic purposes. The aim of this study was (1) to prepare hepatitis B surface antigen (HBsAg)-pulsed human blood DCs, (2) to assess immunogenicity of HBsAg-pulsed DCs in vitro and (3) to evaluate the efficacy of HBsAg-pulsed DCs in hepatitis B (HB) vaccine nonresponders. Human peripheral blood DCs were cultured with HBsAg to prepare HBsAg-pulsed DCs. The expression of immunogenic epitopes of HBsAg on HBsAg-pulsed DCs was assessed in vitro. Finally, HBsAg-pulsed DCs were administered, intradermally to six HB vaccine nonresponders and the levels of antibody to HBsAg (anti-HBs) in the sera were assessed. HB vaccine nonresponders did not exhibit features of immediate, early or delayed adverse reactions due to administration of HBsAg-pulsed DCs. Anti-HBs were detected in the sera of all HB vaccine nonresponders within 28 days after administration of HBsAg-pulsed DCs. This study opens a new field of application of antigen-pulsed DCs for prophylactic purposes when adequate levels of protective antibody cannot be induced by traditional vaccination approaches.

  5. Molecular analysis of Toxoplasma gondii Surface Antigen 1 (SAG1) gene cloned from Toxoplasma gondii DNA isolated from Javanese acute toxoplasmosis

    Science.gov (United States)

    Haryati, Sri; Agung Prasetyo, Afiono; Sari, Yulia; Dharmawan, Ruben

    2018-05-01

    Toxoplasma gondii Surface Antigen 1 (SAG1) is often used as a diagnostic tool due to its immunodominant-specific as antigen. However, data of the Toxoplasma gondii SAG1 protein from Indonesian isolate is limited. To study the protein, genomic DNA was isolated from a Javanese acute toxoplasmosis blood samples patient. A complete coding sequence of Toxoplasma gondii SAG1 was cloned and inserted into an Escherichia coli expression plasmid and sequenced. The sequencing results were subjected to bioinformatics analysis. The Toxoplasma gondii SAG1 complete coding sequences were successfully cloned. Physicochemical analysis revealed the 336 aa of SAG1 had 34.7 kDa of weight. The isoelectric point and aliphatic index were 8.4 and 78.4, respectively. The N-terminal methionine half-life in Escherichia coli was more than 10 hours. The antigenicity, secondary structure, and identification of the HLA binding motifs also had been discussed. The results of this study would contribute information about Toxoplasma gondii SAG1 and benefits for further works willing to develop diagnostic and therapeutic strategies against the parasite.

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

    DEFF Research Database (Denmark)

    Dziegiel, M; 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....

  7. Cell-surface antigens associated with dualtropic and thymotropic murine leukemia viruses inducing thymic and nonthymic lymphomas

    International Nuclear Information System (INIS)

    Haas, M.; Patch, V.

    1980-01-01

    Unique type-specific antigens were detected on cells infected with dualtropic and thymotropic viruses and x-ray-induced T cell- and B cell-malignant lymphomas of C57BL/6 mice. These findings support the contention that T cell lymphoma (TCL)-inducing and B cell lymphoma (BCL)-indcing viruses isolated from x-irradiated C57BL/6 mice are env gene recombinants in which ecotropic gene sequences have been substituted by xenotropic sequences. We found that unique antigenicities are associated with each TCL-inducing and BCL-inducing dualtropic virus, and that the thymotropic TCL-inducing virus isolates represent a separate serologic group. These virus mapping experiments indicated that many serologically different recombinant viruses can be isolated from C57BL/6 mice. It is suggested that many distinct recombinant viruses may exist in lymphomagenic C57BL/6 mice, some of which are associated with specific lyphoma induction

  8. 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)

    2012-01-01

    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. PMID:22984898

  9. 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....

  10. The E7-associated cell-surface antigen: a marker for the 11p13 chromosomal deletion associated with aniridia-Wilms tumor.

    OpenAIRE

    Scoggin, C H; Fisher, J H; Shoemaker, S A; Morse, H; Leigh, T; Riccardi, V M

    1985-01-01

    Unbalanced interstitial deletions of the p13 region of human chromosome 11 have been associated with congenital hypoplasia or aplasia of the iris, mental retardation, ambiguous genitalia, and predisposition to Wilms tumor of the kidney. Utilizing somatic cell hybrids containing either the normal or abnormal chromosome 11 from a child with Wilms tumor and aniridia, we previously mapped the E7 cell-surface antigen to the 11p1300-to-11p15.1 region. To localize even further the site of this antig...

  11. 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...

  12. SnSAG5 is an alternative surface antigen of Sarcocystis neurona strains that is mutually exclusive to SnSAG1.

    Science.gov (United States)

    Crowdus, Carolyn A; Marsh, Antoinette E; Saville, Willliam J; Lindsay, David S; Dubey, J P; Granstrom, David E; Howe, Daniel K

    2008-11-25

    Sarcocystis neurona is an obligate intracellular parasite that causes equine protozoal myeloencephalitis (EPM). Previous work has identified a gene family of paralogous surface antigens in S. neurona called SnSAGs. These surface proteins are immunogenic in their host animals, and are therefore candidate molecules for development of diagnostics and vaccines. However, SnSAG diversity exists in strains of S. neurona, including the absence of the major surface antigen gene SnSAG1. Instead, sequence for an alternative SnSAG has been revealed in two of the SnSAG1-deficient strains. Herein, we present data characterizing this new surface protein, which we have designated SnSAG5. The results indicated that the protein encoded by the SnSAG5 sequence is indeed a surface-associated molecule that has characteristics consistent with the other SAGs identified in S. neurona and related parasites. Importantly, Western blot analyses of a collection of S. neurona strains demonstrated that 6 of 13 parasite isolates express SnSAG5 as a dominant surface protein instead of SnSAG1. Conversely, SnSAG5 was not detected in SnSAG1-positive strains. One strain, which was isolated from the brain of a sea otter, did not express either SnSAG1 or SnSAG5. Genetic analysis with SnSAG5-specific primers confirmed the presence of the SnSAG5 gene in Western blot-positive strains, while also suggesting the presence of a novel SnSAG sequence in the SnSAG1-deficient, SnSAG5-deficient otter isolate. The findings provide further indication of S. neurona strain diversity, which has implications for diagnostic testing and development of vaccines against EPM as well as the population biology of Sarcocystis cycling in the opossum definitive host.

  13. 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.

  14. 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.)

  15. 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

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

    Science.gov (United States)

    Hønge, Bl; Jespersen, S; Medina, C; Té, Ds; da Silva, Zj; Ostergaard, L; Laursen, Al; Wejse, C; Krarup, H; Erikstrup, C

    2014-10-01

    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. 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. Two rapid tests were used in Guinea-Bissau: HBsAg Strip Ref 2034 (VEDA.LAB, Alençon, France; sensitivity 62.3%; specificity 99.2%) and HEPA-SCAN (Bhat Bio-Tech, Bangalore, India; sensitivity 57.1%; specificity 99.7%). In the two tests the ability to obtain the correct outcome depended on the antigen and antibody concentrations, respectively. Sex, age, CD4 cell count and antiretroviral therapy status did not differ between false negative and true positive samples in either of the tests. The study is limited by a low number of anti-HCV positive samples. New diagnostic rapid tests should always be evaluated in the setting in which they will be used before implementation. © 2014 British HIV Association.

  17. Serodiagnosis of bovine trypanosomosis caused by non-tsetse transmitted Trypanosoma (Duttonella) vivax parasites using the soluble form of a Trypanozoon variant surface glycoprotein antigen.

    Science.gov (United States)

    Uzcanga, Graciela L; Pérez-Rojas, Yenis; Camargo, Rocío; Izquier, Adriana; Noda, José A; Chacín, Ronny; Parra, Nereida; Ron, Lenin; Rodríguez-Hidalgo, Richar; Bubis, José

    2016-03-15

    Previous studies have shown that a 64-kDa antigen (p64) that was purified from the Venezuelan TeAp-N/D1 isolate of Trypanosoma (Trypanozoon) equiperdum corresponds to the soluble form of its predominant variant surface glycoprotein (VSG), and exhibited cross-reactivity with Trypanosoma (Duttonella) vivax. The course of experimental acute infections of bovines with T. vivax were followed by measuring whole anti-p64 antibodies and specific anti-p64 IgG and IgM antibodies in animal sera by indirect enzyme-linked immunosorbent assay (ELISA). The value of p64 to diagnose bovine trypanosomosis was also examined using 350 sera from healthy and T. vivax-infected cows living in a trypanosomosis-endemic and enzootic stable area, and 48 sera obtained during a trypanosomosis outbreak. Serological assays showed that ∼ 70-80% of the infected sera contained anti-p64 antibodies, based on the comparative immunodetection of the T. equiperdum clarified antigenic fraction used as a reference test. In the absence of a gold standard, Bayesian analysis for multiple testing estimated a sensitivity and specificity of 71.6% and 98.8%, respectively, for the indirect ELISA using p64 as antigen. An apparent prevalence of 37.7% for bovine trypanosomosis infection was also estimated with a Bayesian approach when the p64 ELISA test was used. Employing blood from acute infected cows, the indirect ELISA response against p64 was contrasted with the microhematocrit centrifuge method and analyses by polymerase chain reaction (PCR) using specific primers targeting the inter-specific length variation of the internal transcribed spacer 1 region of the 18S ribosomal gene. The efficiency of p64 for the detection of anti-trypanosome antibodies in acute infected bovines was also corroborated serologically by comparing its response to that of the Indonesian Trypanosoma evansi Rode Trypanozoon antigen type (RoTat) 1.2 VSG, which possesses high specificity and sensitivity. As expected, PCR was the best

  18. 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.

  19. 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

    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...... subset of PfEMP1 variants tends to dominate in non-immune patients and in patients with severe malaria, while more diverse subsets relate to uncomplicated infection and higher levels of pre-existing protective immunity. METHODOLOGY/PRINCIPAL FINDINGS: Here, we use the available molecular and serological......-host and diverse blocks that are favoured by immune selection at the population level. CONCLUSIONS/SIGNIFICANCE: The application of a monotonic dominance profile to VSAs encoded by a gene family generates two opposing selective forces and, consequently, two distinct clusters of genes emerge in adaptation to naïve...

  20. 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.

  1. A Novel Platform for the Potentiation of Therapeutic Antibodies Based on Antigen-Dependent Formation of IgG Hexamers at the Cell Surface

    DEFF Research Database (Denmark)

    de Jong, R. N.; Beurskens, F. J.; Verploegen, S.

    2016-01-01

    IgG antibodies can organize into ordered hexamers on cell surfaces after binding their antigen. These hexamers bind the first component of complement C1 inducing complement-dependent target cell killing. Here, we translated this natural concept into a novel technology platform (HexaBody technology......) for therapeutic antibody potentiation. We identified mutations that enhanced hexamer formation and complement activation by IgG1 antibodies against a range of targets on cells from hematological and solid tumor indications. IgG1 backbones with preferred mutations E345K or E430G conveyed a strong ability to induce...... conditional complement-dependent cytotoxicity (CDC) of cell lines and chronic lymphocytic leukemia (CLL) patient tumor cells, while retaining regular pharmacokinetics and biopharmaceutical developability. Both mutations potently enhanced CDC- and antibody-dependent cellular cytotoxicity (ADCC) of a type II CD...

  2. Ultra-deep sequencing reveals high prevalence and broad structural diversity of hepatitis B surface antigen mutations in a global population.

    Science.gov (United States)

    Gencay, Mikael; Hübner, Kirsten; Gohl, Peter; Seffner, Anja; Weizenegger, Michael; Neofytos, Dionysios; Batrla, Richard; Woeste, Andreas; Kim, Hyon-Suk; Westergaard, Gaston; Reinsch, Christine; Brill, Eva; Thu Thuy, Pham Thi; Hoang, Bui Huu; Sonderup, Mark; Spearman, C Wendy; Pabinger, Stephan; Gautier, Jérémie; Brancaccio, Giuseppina; Fasano, Massimo; Santantonio, Teresa; Gaeta, Giovanni B; Nauck, Markus; Kaminski, Wolfgang E

    2017-01-01

    The diversity of the hepatitis B surface antigen (HBsAg) has a significant impact on the performance of diagnostic screening tests and the clinical outcome of hepatitis B infection. Neutralizing or diagnostic antibodies against the HBsAg are directed towards its highly conserved major hydrophilic region (MHR), in particular towards its "a" determinant subdomain. Here, we explored, on a global scale, the genetic diversity of the HBsAg MHR in a large, multi-ethnic cohort of randomly selected subjects with HBV infection from four continents. A total of 1553 HBsAg positive blood samples of subjects originating from 20 different countries across Africa, America, Asia and central Europe were characterized for amino acid variation in the MHR. Using highly sensitive ultra-deep sequencing, we found 72.8% of the successfully sequenced subjects (n = 1391) demonstrated amino acid sequence variation in the HBsAg MHR. This indicates that the global variation frequency in the HBsAg MHR is threefold higher than previously reported. The majority of the amino acid mutations were found in the HBV genotypes B (28.9%) and C (25.4%). Collectively, we identified 345 distinct amino acid mutations in the MHR. Among these, we report 62 previously unknown mutations, which extends the worldwide pool of currently known HBsAg MHR mutations by 22%. Importantly, topological analysis identified the "a" determinant upstream flanking region as the structurally most diverse subdomain of the HBsAg MHR. The highest prevalence of "a" determinant region mutations was observed in subjects from Asia, followed by the African, American and European cohorts, respectively. Finally, we found that more than half (59.3%) of all HBV subjects investigated carried multiple MHR mutations. Together, this worldwide ultra-deep sequencing based genotyping study reveals that the global prevalence and structural complexity of variation in the hepatitis B surface antigen have, to date, been significantly underappreciated.

  3. 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.

  4. 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.

  5. Construction of a hepatitis B virus neutralizing chimeric monoclonal antibody recognizing escape mutants of the viral surface antigen (HBsAg).

    Science.gov (United States)

    Golsaz-Shirazi, Forough; Amiri, Mohammad Mehdi; Farid, Samira; Bahadori, Motahareh; Bohne, Felix; Altstetter, Sebastian; Wolff, Lisa; Kazemi, Tohid; Khoshnoodi, Jalal; Hojjat-Farsangi, Mohammad; Chudy, Michael; Jeddi-Tehrani, Mahmood; Protzer, Ulrike; Shokri, Fazel

    2017-08-01

    Hepatitis B virus (HBV) infection is a global burden on the health-care system and is considered as the tenth leading cause of death in the world. Over 248 million patients are currently suffering from chronic HBV infection worldwide and annual mortality rate of this infection is 686000. The "a" determinant is a hydrophilic region present in all antigenic subtypes of hepatitis B surface antigen (HBsAg), and antibodies against this region can neutralize the virus and are protective against all subtypes. We have recently generated a murine anti-HBs monoclonal antibody (4G4), which can neutralize HBV infection in HepaRG cells and recognize most of the escape mutant forms of HBsAg. Here, we describe the production and characterization of the chimeric human-murine antibody 4G4 (c-4G4). Variable region genes of heavy and light chains of the m-4G4 were cloned and fused to constant regions of human kappa and IgG1 by splice overlap extension (SOE) PCR. The chimeric antibody was expressed in Chinese Hamster Ovary (CHO)-K1 cells and purified from culture supernatant. Competition ELISA proved that both antibodies bind the same epitope within HBsAg. Antigen-binding studies using ELISA and Western blot showed that c-4G4 has retained the affinity and specificity of the parental murine antibody, and displayed a similar pattern of reactivity to 13 escape mutant forms of HBsAg. Both, the parental and c-4G4 showed a comparably high HBV neutralization capacity in cell culture even at the lowest concentration (0.6μg/ml). Due to the ability of c-4G4 to recognize most of the sub-genotypes and escape mutants of HBsAg, this antibody either alone or in combination with other anti-HBs antibodies could be considered as a potent alternative for Hepatitis B immune globulin (HBIG) as an HBV infection prophylactic or for passive immunotherapy against HBV infection. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 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

  7. 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.

  8. Real time detection of antibody-antigen interaction using a laser scanning confocal imaging-surface plasmon resonance system

    International Nuclear Information System (INIS)

    Zhang Hong-Yan; Yang Li-Quan; Ning Ting-Yin; Liu Wei-Min; Sun Jia-Yu; Wang Peng-Fei; Meng Lan; Nie Jia-Cai

    2012-01-01

    A laser scanning confocal imaging-surface plasmon resonance (LSCI-SPR) instrument integrated with a wavelength-dependent surface plasmon resonance (SPR) sensor and a laser scanning confocal microscopy (LSCM) is built to detect the bonding process of human IgG and fluorescent-labeled affinity purified antibodies in real time. The shifts of resonant wavelength at different reaction time stages are obtained by SPR, corresponding well with the changes of the fluorescence intensity collected by using LSCM. The instrument shows the merits of the combination and complementation of the SPR and LSCM, with such advantages as quantificational analysis, high spatial resolution and real time monitor, which are of great importance for practical applications in biosensor and life science. (general)

  9. A Microfluidic Chip Based on Localized Surface Plasmon Resonance for Real-Time Monitoring of Antigen-Antibody Reactions

    Science.gov (United States)

    Hiep, Ha Minh; Nakayama, Tsuyoshi; Saito, Masato; Yamamura, Shohei; Takamura, Yuzuru; Tamiya, Eiichi

    2008-02-01

    Localized surface plasmon resonance (LSPR) connecting to noble metal nanoparticles is an important issue for many analytical and biological applications. Therefore, the development of microfluidic LSPR chip that allows studying biomolecular interactions becomes an essential requirement for micro total analysis systems (µTAS) integration. However, miniaturized process of the conventional surface plasmon resonance system has been faced with some limitations, especially with the usage of Kretschmann configuration in total internal reflection mode. In this study, we have tried to solve this problem by proposing a novel microfluidic LSPR chip operated with a simple collinear optical system. The poly(dimethylsiloxane) (PDMS) based microfluidic chip was fabricated by soft-lithography technique and enables to interrogate specific insulin and anti-insulin antibody reaction in real-time after immobilizing antibody on its surface. Moreover, the sensing ability of microfluidic LSPR chip was also evaluated with various glucose concentrations. The kinetic constant of insulin and anti-insulin antibody was determined and the detection limit of 100 ng/mL insulin was archived.

  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. 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)

  12. Characterization of foot- and mouth disease virus antigen by surface-enhanced laser desorption ionization-time of flight-mass spectrometry in aqueous and oil-emulsion formulations

    NARCIS (Netherlands)

    Harmsen, M.M.; Jansen, J.; Westra, D.F.; Coco-Martin, J.M.

    2010-01-01

    We have used a novel method, surface-enhanced laser desorption ionization-time of flight-mass spectrometry (SELDI-TOF-MS), to characterize foot-and-mouth disease virus (FMDV) vaccine antigens. Using specific capture with FMDV binding recombinant antibody fragments and tryptic digestion of FMDV

  13. Antigens of hepatitis B virus: failure to detect HBeAg on the surfaces of HBsAg forms

    Energy Technology Data Exchange (ETDEWEB)

    Gerin, J L [Oak Ridge National Lab., Rockville, MD; Shih, J W.K.; McAuliffee, V J; Purcell, R H

    1978-01-01

    The particulate forms of HBsAg were analysed for the presence of HBeAG on their surfaces. By immunodiffusion analysis, anti-HBe did not form precipitin bands with the purified forms of HBsAg and hyperimmune guinea pig antisera to these forms did not react with HBeAg. Lines of non-identity were observed between the HBeAg determinants (e/sub 1/ and e/sub 2/) and the Dane particles and filaments isolated from an HBeAg-positive serum. Finally, anti-HBe failed to precipitate the polymerase-positive subpopulation of Dane particles, indicating that anti-HBe has no direct role in virus neutralization.

  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. Immunity to tumour antigens.

    Science.gov (United States)

    Li, Geng; Ali, Selman A; McArdle, Stephanie E B; Mian, Shahid; Ahmad, Murrium; Miles, Amanda; Rees, Robert C

    2005-01-01

    During the last decade, a large number of human tumour antigens have been identified. These antigens are classified as tumour-specific shared antigens, tissue-specific differentiation antigens, overexpressed antigens, tumour antigens resulting from mutations, viral antigens and fusion proteins. Antigens recognised by effectors of immune system are potential targets for antigen-specific cancer immunotherapy. However, most tumour antigens are self-proteins and are generally of low immunogenicity and the immune response elicited towards these tumour antigens is not always effective. Strategies to induce and enhance the tumour antigen-specific response are needed. This review will summarise the approaches to discovery of tumour antigens, the current status of tumour antigens, and their potential application to cancer treatment.

  16. 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...

  17. 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

    BACKGROUND: The insertion of parasite antigens into the host erythrocyte membrane and the structure and distribution of Plasmodium falciparum adhesion receptors on that membrane are poorly understood. Laser scanning confocal microscopy (LSCM) and a novel labelling and fixation method have been used...... fluorochromes has been developed for laser scanning confocal optical microscopy and the analysis of the developmental expression of malaria adhesion antigens....

  18. Use of radioimmune assay in investigating reagents to be used in the immunocytochemical localization of hepatitis B surface antigen in immune complexes in the kidney of patients with membranous nephropathy and Australia antigenaemia

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe-Coote, S [South African Medical Research Council, Tygerberg (South Africa). Inst. for Electron Microscopy

    1983-09-01

    Radioimmune assay (RIA) was used to investigate the effect of fixatives on antigenicity of the hepatitis B surface antigen (HBsAg) and the effect of pronase on the elution of antibody (Ab) from the HBsAg-Ab complex. The effect of pronase on Ab elution was also tested on sections of kidney from a patient with the immune complex disease systemic lupus erythematosus (SLE). Immunoglobulin G (IgG) was located in pronase treated and untreated sections using the indirect immunoperoxidase technique. Glutareldehyde was shown to be the fixative of choice for studies involving HBsAg. All fixatives were shown to have less effect on antigenicity at 4/sup 0/C than at room temperature. Osmium tetroxide reduced antigenicity to one-third, even at 4/sup 0/C. RIA and SLE kidney section studies showed that Ab was eluted from immune complexes by pronase. Pre-fixation of the antigen (Ag) by glutaraldehyde appears to have no effect on the final elution, although fixation after pronase treatment seemed to enhance the elution effects. The availability of an RIA kit with HBsAg- and Ab-coated beads was of great assistance in evaluating reagents to be used in immunoperoxidase studies of HBsAg in immune complexes of patients with membranous nephropathy and Australia antigenaemia.

  19. Models of Community-Based Hepatitis B Surface Antigen Screening Programs in the U.S. and Their Estimated Outcomes and Costs

    Science.gov (United States)

    Rein, David B.; Lesesne, Sarah B.; Smith, Bryce D.; Weinbaum, Cindy M.

    2011-01-01

    Objectives Information on the process and method of service delivery is sparse for hepatitis B surface antigen (HBsAg) testing, and no systematic study has evaluated the relative effectiveness or cost-effectiveness of different HBsAg screening models. To address this need, we compared five specific community-based screening programs. Methods We funded five HBsAg screening programs to collect information on their design, costs, and outcomes of participants during a six-month observation period. We categorized programs into four types of models. For each model, we calculated the number screened, the number screened as per Centers for Disease Control and Prevention (CDC) recommendations, and the cost per screening. Results The models varied by cost per person screened and total number of people screened, but they did not differ meaningfully in the proportion of people screened following CDC recommendations, the proportion of those screened who tested positive, or the proportion of those who newly tested positive. Conclusions Integrating screening into outpatient service settings is the most cost-effective method but may not reach all people needing to be screened. Future research should examine cost-effective methods that expand the reach of screening into communities in outpatient settings. PMID:21800750

  20. 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.

  1. The genetic diversity of merozoite surface antigen 1 (MSA-1) among Babesia bovis detected from cattle populations in Thailand, Brazil and Ghana.

    Science.gov (United States)

    Nagano, Daisuke; Sivakumar, Thillaiampalam; De De Macedo, Alane Caine Costa; Inpankaew, Tawin; Alhassan, Andy; Igarashi, Ikuo; Yokoyama, Naoaki

    2013-11-01

    In the present study, we screened blood DNA samples obtained from cattle bred in Brazil (n=164) and Ghana (n=80) for Babesia bovis using a diagnostic PCR assay and found prevalences of 14.6% and 46.3%, respectively. Subsequently, the genetic diversity of B. bovis in Thailand, Brazil and Ghana was analyzed, based on the DNA sequence of merozoite surface antigen-1 (MSA-1). In Thailand, MSA-1 sequences were relatively conserved and found in a single clade of the phylogram, while Brazilian MSA-1 sequences showed high genetic diversity and were dispersed across three different clades. In contrast, the sequences from Ghanaian samples were detected in two different clades, one of which contained only a single Ghanaian sequence. The identities among the MSA-1 sequences from Thailand, Brazil and Ghana were 99.0-100%, 57.5-99.4% and 60.3-100%, respectively, while the similarities among the deduced MSA-1 amino acid sequences within the respective countries were 98.4-100%, 59.4-99.7% and 58.7-100%, respectively. These observations suggested that the genetic diversity of B. bovis based on MSA-1 sequences was higher in Brazil and Ghana than in Thailand. The current data highlight the importance of conducting extensive studies on the genetic diversity of B. bovis before designing immune control strategies in each surveyed country.

  2. 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.

  3. Evaluation of a solid-phase RIA technique and a solid-phase ELISA technique for demonstrating hepatitis-B surface antigen

    International Nuclear Information System (INIS)

    Vranckx, R.; Cole, J.; Peetermans, M.

    1978-01-01

    The sensitivities of a solid-phase radioimmunoassay (RIA), a solid-phase enzyme immunoassay (ELISA) and a haemagglutination test (RPHA) for the detection of the hepatitis-B surface antigen (HBsAg) were compared (1) by screening a panel of 300 sera (97 positives and 203 negatives), and (2) by titrating serial dilutions of 10 positive sera. Ninety-seven sera were positive by RIA, 95% were detected by ELISA and 81% were detected by RPHA. In the serial dilutions, the average end-points of the titrations were 0.005ng/ml for RIA, 0.01ng/ml for ELISA and 0.04 ng/ml for RPHA. It can be concluded that the sensitivity of the ELISA test is intermediate between that of the RIA and the RPHA. The ELISA and the RPHA tests seem to be a little more sensitive for the detection of subtype ay than for the detection of subtype ad. (author)

  4. 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.

  5. Improved porous silicon (P-Si) microarray based PSA (prostate specific antigen) immunoassay by optimized surface density of the capture antibody

    Science.gov (United States)

    Lee, SangWook; Kim, Soyoun; Malm, Johan; Jeong, Ok Chan; Lilja, Hans; Laurell, Thomas

    2014-01-01

    Enriching the surface density of immobilized capture antibodies enhances the detection signal of antibody sandwich microarrays. In this study, we improved the detection sensitivity of our previously developed P-Si (porous silicon) antibody microarray by optimizing concentrations of the capturing antibody. We investigated immunoassays using a P-Si microarray at three different capture antibody (PSA - prostate specific antigen) concentrations, analyzing the influence of the antibody density on the assay detection sensitivity. The LOD (limit of detection) for PSA was 2.5ngmL−1, 80pgmL−1, and 800fgmL−1 when arraying the PSA antibody, H117 at the concentration 15µgmL−1, 35µgmL−1 and 154µgmL−1, respectively. We further investigated PSA spiked into human female serum in the range of 800fgmL−1 to 500ngmL−1. The microarray showed a LOD of 800fgmL−1 and a dynamic range of 800 fgmL−1 to 80ngmL−1 in serum spiked samples. PMID:24016590

  6. 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

  7. 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)

  8. Presencia del antígeno de superficie del virus hepatitis B en donantes de sangre Presence of hepatitis B surface antigen in blood donors

    Directory of Open Access Journals (Sweden)

    Yarelis Prieto Hernández

    2013-06-01

    , applied and prospective study was conducted with blood donors in Sandino municipality from September 2010 to August 2011; an epidemiological survey was applied along with hepatitis B surface antigen performed to a sample of 1420 donors. Results: 18 positive hepatitis B surface antigen were found (1,3%, ages from 18-34 (45,2% and Caucasian race prevailed (60,2%, the 80,7% had no surgical interventions, the sexual preference was heterosexual(99,3% and those not having tattoos predominated with 99,3%. Regarding the last dental treatment, the group who did not undergo this treatment was more representative 67,2% finding a statistical significant difference. Conclusions: blood donors presented a high prevalence of hepatitis B virus in Sandino municipality, where no association was found among age, race, surgical interventions, sexual preference, tattoos and the onset of hepatitis B. On the contrary, a relationship between hepatitis B and dental treatment was found.

  9. 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.

  10. Natural selection promotes antigenic evolvability.

    Directory of Open Access Journals (Sweden)

    Christopher J Graves

    Full Text Available 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

  11. Glycosylation Alters Dimerization Properties of a Cell-surface Signaling Protein, Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 (CEACAM1)*

    Science.gov (United States)

    Zhuo, You; Yang, Jeong-Yeh; Moremen, Kelley W.; Prestegard, James H.

    2016-01-01

    Human carcinoembryonic antigen-related cell adhesion molecule 1 (C?/Au: EACAM1) is a cell-surface signaling molecule involved in cell adhesion, proliferation, and immune response. It is also implicated in cancer angiogenesis, progression, and metastasis. This diverse set of effects likely arises as a result of the numerous homophilic and heterophilic interactions that CEACAM1 can have with itself and other molecules. Its N-terminal Ig variable (IgV) domain has been suggested to be a principal player in these interactions. Previous crystal structures of the β-sandwich-like IgV domain have been produced using Escherichia coli-expressed material, which lacks native glycosylation. These have led to distinctly different proposals for dimer interfaces, one involving interactions of ABED β-strands and the other involving GFCC′C″ β-strands, with the former burying one prominent glycosylation site. These structures raise questions as to which form may exist in solution and what the effect of glycosylation may have on this form. Here, we use NMR cross-correlation measurements to examine the effect of glycosylation on CEACAM1-IgV dimerization and use residual dipolar coupling (RDC) measurements to characterize the solution structure of the non-glycosylated form. Our findings demonstrate that even addition of a single N-linked GlcNAc at potential glycosylation sites inhibits dimer formation. Surprisingly, RDC data collected on E. coli expressed material in solution indicate that a dimer using the non-glycosylated GFCC′C″ interface is preferred even in the absence of glycosylation. The results open new questions about what other factors may facilitate dimerization of CEACAM1 in vivo, and what roles glycosylation may play in heterophylic interactions. PMID:27471271

  12. Diversity of Sarcocystis spp shed by opossums in Brazil inferred with phylogenetic analysis of DNA coding ITS1, cytochrome B, and surface antigens.

    Science.gov (United States)

    Valadas, Samantha Y O B; da Silva, Juliana I G; Lopes, Estela Gallucci; Keid, Lara B; Zwarg, Ticiana; de Oliveira, Alice S; Sanches, Thaís C; Joppert, Adriana M; Pena, Hilda F J; Oliveira, Tricia M F S; Ferreira, Helena L; Soares, Rodrigo M

    2016-05-01

    Although few species of Sarcocystis are known to use marsupials of the genus Didelphis as definitive host, an extensive diversity of alleles of surface antigen genes (sag2, sag3, and sag4) has been described in samples of didelphid opossums in Brazil. In this work, we studied 25 samples of Sarcocystis derived from gastrointestinal tract of opossums of the genus Didelphis by accessing the variability of sag2, sag3, sag4, gene encoding cytochrome b (cytB) and first internal transcribed spacer (ITS1). Reference samples of Sarcocystis neurona (SN138) and Sarcocystis falcatula (SF1) maintained in cell culture were also analyzed. We found four allele variants of cytB, seven allele variants of ITS1, 10 allele variants of sag2, 13 allele variants of sag3, and 6 allele variants of sag4. None of the sporocyst-derived sequences obtained from Brazilian opossums revealed 100% identity to SN138 at cytB gene, nor to SN138 or SF1 at ITS1 locus. In addition, none of the sag alleles were found identical to either SF1 or SN138 homologous sequences, and a high number of new sag allele types were found other than those previously described in Brazil. Out of ten sag2 alleles, four are novel, while eight out of 13 sag3 alleles are novel and one out of six sag4 alleles is novel. Further studies are needed to clarify if such a vast repertoire of allele variants of Sarcocystis is the consequence of re-assortments driven by sexual exchange, in order to form individuals with highly diverse characteristics, such as pathogenicity, host spectrum, among others or if it only represents allele variants of different species with different biological traits. Copyright © 2016 Elsevier Inc. All rights reserved.

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

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    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.

  14. 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.

  15. Seroprevalence of Hepatitis B surface antigen, antibodies to the Hepatitis C virus, and human immunodeficiency virus in a hospital-based population in Jaipur, Rajasthan

    Directory of Open Access Journals (Sweden)

    Sood Smita

    2010-01-01

    Full Text Available Background: Hepatitis B, hepatitis C, and HIV infections are a serious global and public health problem. To assess the magnitude and dynamics of disease transmission and for its prevention and control, the study of its seroprevalence is important. A private hospital catering to the needs of a large population represents an important center for serological surveys. Available data, at Rajasthan state level, on the seroprevalence of these bloodborne pathogens is also very limited. Objective: A study was undertaken to estimate the seroprevalence of hepatitis B surface antigen (HBsAg and antibodies to hepatitis C (anti-HCV Ab and human immunodeficiency virus (anti-HIV Ab in both the sexes and different age groups in a hospital-based population in Jaipur, Rajasthan. Materials and Methods: Serum samples collected over a period of 14 months from patients attending OPDs and admitted to various IPDs of Fortis Escorts Hospital, Jaipur, were subjected within the hospital-based lab for the detection of HBsAg and anti-HCV Ab and anti-HIV Ab using rapid card tests. This was followed by further confirmation of all reactive samples by a microparticle enzyme immunoassay (Abbott AxSYM at Super Religare Laboratories (formerly SRL Ranbaxy Reference Lab, Mumbai. Results: The seroprevalence of HBsAg was found to be 0.87%, of anti-HCV Ab as 0.28%, and of anti-HIV Ab as 0.35%. Conclusion: The study throws light on the magnitude of viral transmission in the community in the state of Rajasthan and provides a reference for future studies.

  16. [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.

  17. A novel method for sensitive, low-cost and portable detection of hepatitis B surface antigen using a personal glucose meter.

    Science.gov (United States)

    Taebi, Saeed; Keyhanfar, Mehrnaz; Noorbakhsh, Abdollah

    2018-04-12

    Hepatitis B virus (HBV) infection is the major public health problem leading cause of death worldwide. The most important diagnostic marker for this infection is hepatitis B surface antigen (HBsAg). In this study, a novel, inexpensive, portable and sensitive ELISA method was designed and investigated for diagnosis of HBsAg based on the functionalized Fe 3 O 4 and Al 2 O 3 nanoparticles, with the strategy for detecting the concentration of glucose using a cheap and accessible personal glucose meter (PGM). The ELISA system was constructed using hepatitis B antibody against HBsAg immobilized on streptavidin coated magnetic iron oxide particles (S-Fe 3 O 4 ) as the capture antibody (Ab 1 ). In addition, another hepatitis B antibody against different epitope of HBsAg (Ab 2 ) and glucoamylase both were immobilized on Al 2 O 3 nanoparticles. After formation of the sandwich immune complex between Ab 1 and Ab 2 immobilized on S-Fe 3 O 4 and Al 2 O 3 NPs, respectively, through HBsAg, starch was converted into glucose using glucoamylase. Then, the glucose concentration was measured using PGM. The concentration of HBsAg was calculated based on the linear relation between the concentrations of HBsAg and glucose. Under optimal conditions, this assay showed detection limit values of 0.3 to 0.4 ng ml -1 for "ay" and "ad" subtypes of HBsAg, respectively. The results indicate that the designed assay is comparable to the commercial kits in terms of sensitivity, on-site, specificity, cost, simplicity, portability and reproducibility. The presented method can be used in disadvantaged areas of the world and blood transfusion centers. To the best of our knowledge, this is the first report of using PGMs for HBSAg detection. Copyright © 2018 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    1986-01-01

    Two 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

  19. 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)

  20. 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

  1. A new trivalent SnSAG surface antigen chimera for efficient detection of antibodies against Sarcocystis neurona and diagnosis of equine protozoal myeloencephalitis.

    Science.gov (United States)

    Yeargan, Michelle; de Assis Rocha, Izabela; Morrow, Jennifer; Graves, Amy; Reed, Stephen M; Howe, Daniel K

    2015-05-01

    Enzyme-linked immunosorbent assays (ELISAs) based on the SnSAG surface antigens of Sarcocystis neurona provide reliable detection of infection by the parasite. Moreover, accurate serodiagnosis of equine protozoal myeloencephalitis (EPM) is achieved with the SnSAG ELISAs by measuring antibodies in serum and cerebrospinal fluid (CSF) to reveal active infection in the central nervous system. Two independent ELISAs based on recombinant (r)SnSAG2 or a chimeric fusion of SnSAG3 and SnSAG4 (rSnSAG4/3) are currently used together for EPM serodiagnosis to overcome varied antibody responses in different horses. To achieve reliable antibody detection with a single ELISA instead of 2 separate ELISAs, rSnSAG2 was fused with rSnSAG4/3 into a single trivalent protein, designated rSnSAG2/4/3. Paired serum and CSF from 163 horses were tested with all 3 ELISAs. When the consensus antibody titers obtained with the rSnSAG2 and rSnSAG4/3 ELISAs were compared to the single SAG2/4/3 ELISA titers, Spearman rank correlation coefficients of ρ = 0.74 and ρ = 0.90 were obtained for serum and CSF, respectively, indicating strong agreement between the tests. When the rSnSAG2 and rSnSAG4/3 consensus serum-to-CSF titer ratio was compared to the rSnSAG2/4/3 serum-to-CSF titer ratio, the Spearman correlation coefficient was ρ = 0.87, again signifying strong agreement. Importantly, comparing the diagnostic interpretation of the serum-to-CSF titer ratios yielded a Cohen kappa value of 0.77. These findings suggest that the single ELISA based on the trivalent rSnSAG2/4/3 will provide serologic and diagnostic results that are highly comparable to the consensus of the 2 independent ELISAs based on rSnSAG2 and rSnSAG4/3. © 2015 The Author(s).

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

    Directory of Open Access Journals (Sweden)

    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

  4. 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 children aged 1-23 months; infections and infestation (8) among persons age 2-18 years blood and lymphatic systemic disorders; and general disorders and administration site conditions among persons age >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.

  5. Binding of antibodies to the extractable nuclear antigens SS-A/Ro and SS-B/La is induced on the surface of human keratinocytes by ultraviolet light (UVL): Implications for the pathogenesis of photosensitive cutaneous lupus

    International Nuclear Information System (INIS)

    Furukawa, F.; Kashihara-Sawami, M.; Lyons, M.B.; Norris, D.A.

    1990-01-01

    Autoantibodies to the non-histone nucleoprotein antigens SS-A/Ro, SS-B/La, and RNP are highly associated with photosensitive cutaneous lupus erythematosus (LE). In order to better understand the potential mechanisms of ultraviolet (UV) light on photosensitivity in patients with cutaneous LE, we designed immunopathologic in vitro and in vivo experiments to evaluate the effects of UV on the binding of such autoantibodies to the surface of human keratinocytes, one major target of immunologic damage in photosensitive LE. Short-term 2% paraformaldehyde fixation of suspensions of cultured human keratinocytes previously incubated with monospecific antiserum probes enabled the detection of ENA expression on the cell surface by flow-cytometry analysis. UVB light (280-320 nm) induced the binding of monospecific antibody probes for SS-A/Ro and SS-B/La on keratinocytes in a dose-dependent pattern with maximal induction observed at the dose of 200 mJ/cm2 UVB. Binding of SS-A/Ro, SS-B/La, and RNP antibody was augmented strongly, but binding of anti-Sm was very weak. In contrast, UVA (320-400 nm) light had no effect on the induction of binding of these antibody probes. Identical results were seen by standard immunofluorescence techniques. Hydroxyurea-treated keratinocytes showed similar induction of those antigens by UVB irradiation, which suggested that ENA expression on cultured keratinocytes by UVB were cell-cycle independent. Tunicamycin, an inhibitor of glycosylation of proteins, reduced UVB light effect on the SS-A/Ro and SS-B/La antigen's expression. These in vitro FACS analyses revealed that ENA augmentation on the keratinocyte cell surface was dose dependent, UVB dependent, glycosylation dependent, and cell-cycle independent. In vivo ENA augmentation on the keratinocyte surface was examined in suction blister epidermal roofs

  6. 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

  7. 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

  8. Detection of different categories of hepatitis B virus (HBV) infection in a multi-regional study comparing the clinical sensitivity of hepatitis B surface antigen and HBV-DNA testing

    DEFF Research Database (Denmark)

    Lelie, Nico; Bruhn, Roberta; Busch, Michael

    2017-01-01

    BACKGROUND: Twenty-two users of individual donation nucleic acid amplification technology (ID-NAT) in six geographical regions provided detailed hepatitis B virus (HBV) infection data in first-time, lapsed, and repeat donations and classified confirmed HBV-positive donors into different infection...... categories. These data were used to compare the clinical sensitivity of hepatitis B surface antigen (HBsAg) and HBV-DNA testing. STUDY DESIGN AND METHODS: In total 10,981,776 donations from South Africa, Egypt, the Mediterranean, North and Central Europe, South East Asia, and Oceania were screened for HBV...

  9. Binding Properties of Streptococcus gordonii SspA and SspB (Antigen I/II Family) Polypeptides Expressed on the Cell Surface of Lactococcus lactis MG1363

    OpenAIRE

    Holmes, Ann R.; Gilbert, Christophe; Wells, Jeremy M.; Jenkinson, Howard F.

    1998-01-01

    The oral bacterium Streptococcus gordonii expresses two cell wall-associated polypeptides, designated SspA (1,542 amino acid residues) and SspB (1,462 amino acid residues), that have 70% sequence identity. These polypeptides are members of the antigen I/II family of oral streptococcal adhesins and mediate the binding of streptococci to salivary glycoproteins, collagen, and other oral microorganisms such as Actinomyces naeslundii. To determine if SspA and SspB have differential binding propert...

  10. 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

  11. Leukemia-associated antigens in man.

    Science.gov (United States)

    Brown, G; Capellaro, D; Greaves, M

    1975-12-01

    Rabbit antisera raised against acute lymphoblastic leukemia (ALL) cells were used to distinguish ALL from other leukemias, to identify rare leukemia cells in the bone marrow of patients in remission, and to define human leukemia-associated antigens. Antibody binding was studied with the use of immunofluorescence reagents and the analytic capacity of the Fluorescence Activated Cell Sorter-1 (FACS-1). The results indicated that most non-T-cell ALL have three leukemia-associated antigens on their surface which are absent from normal lymphoid cells: 1) an antigen shared with myelocytes, myeloblastic leukemia cells, and fetal liver (hematopoietic) cells; 2) an antigen shared with a subset of intermediate normoblasts in normal bone marrow and fetal liver; and 3) an antigen found thus far only on non-T-cell ALL and in some acute undifferentiated leukemias, which we therefore regard as a strong candidate for a leukemia-specific antigen. These antigens are absent from a subgroup of ALL patients in which the lymphoblasta express T-cell surface markers. Preliminary studies on the bone marrow samples of patients in remission indicated that rare leukemia cells were present in some samples. The implications of these findings with respect to the heterogeneity and cell origin(s) of ALL, its diagnosis, and its potential monitoring during treatment were discussed.

  12. 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

    ) in older semi-immune children. Establishment of the genetic mechanism underlying changes in VSA expression in response to in vitro selective pressure is now possible because of the availability of the entire genomic sequence of the P. falciparum clone 3D7. As a first step towards direct molecular...... 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...... and epidemiologically diverse areas of endemic parasite transmission. The described selection method appears a useful tool in the identification of genes encoding VSA involved in severe and life-threatening P. falciparum malaria....

  13. 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

  14. 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.

  15. Enhancement of sensitivity and specificity of the fluoroimmunoassay of Hepatitis B virus surface antigen through "flexible" coupling between quantum dots and antibody

    NARCIS (Netherlands)

    Zeng, Qinghui; Zhang, Youlin; Song, Kai; Kong, Xianggui; Aalders, Maurice C. G.; Zhang, Hong

    2009-01-01

    Quantum dots (QDs) are widely used in the immune detection. Yet, the sensitivity and specificity of the immune detection are not satisfactory because the binding sites of QDs onto antibody (Ab) are often arbitrary and the influence of the large surface electronic potential energy of QDs on the

  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

    The binding of two alpha-galactophilic lectins, Marasmius oreades agglutinin (MOA), and Griffonia simplicifolia I isolectin B(4) (GS I-B(4)) to neoglycoproteins and natural glycoproteins were compared in a surface phase assay. Neoglycoproteins carrying various alpha-galactosylated glycans and lam...

  17. The neck region of the C-type lectin DC-SIGN regulates its surface spatiotemporal organization and virus-binding capacity on antigen presenting cells

    NARCIS (Netherlands)

    Manzo, C.; Torreno-Pina, J.A.; Joosten, B.; Reinieren-Beeren, I.; Gualda, E.J.; Loza-Alvarez, P.; Figdor, Carl; Garcia Parajo, M.F.; Cambi, A.

    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

  18. The Neck Region of the C-type Lectin DC-SIGN Regulates Its Surface Spatiotemporal Organization and Virus-binding Capacity on Antigen-presenting Cells

    NARCIS (Netherlands)

    Manzo, C.; Torreno-Pina, J.A.; Joosten, B.; Reinieren-Beeren, I.; Gualda, E.J.; Loza-Alvarez, P.; Figdor, C.G.; Garcia-Parajo, M.F.; Cambi, A.

    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

  19. 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

  20. Protamine-based nanoparticles as new antigen delivery systems.

    Science.gov (United States)

    González-Aramundiz, José Vicente; Peleteiro Olmedo, Mercedes; González-Fernández, África; Alonso Fernández, María José; Csaba, Noemi Stefánia

    2015-11-01

    The use of biodegradable nanoparticles as antigen delivery vehicles is an attractive approach to overcome the problems associated with the use of Alum-based classical adjuvants. Herein we report, the design and development of protamine-based nanoparticles as novel antigen delivery systems, using recombinant hepatitis B surface antigen as a model viral antigen. The nanoparticles, composed of protamine and a polysaccharide (hyaluronic acid or alginate), were obtained using a mild ionic cross-linking technique. The size and surface charge of the nanoparticles could be modulated by adjusting the ratio of the components. Prototypes with optimal physicochemical characteristics and satisfactory colloidal stability were selected for the assessment of their antigen loading capacity, antigen stability during storage and in vitro and in vivo proof-of-concept studies. In vitro studies showed that antigen-loaded nanoparticles induced the secretion of cytokines by macrophages more efficiently than the antigen in solution, thus indicating a potential adjuvant effect of the nanoparticles. Finally, in vivo studies showed the capacity of these systems to trigger efficient immune responses against the hepatitis B antigen following intramuscular administration, suggesting the potential interest of protamine-polysaccharide nanoparticles as antigen delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Antigen injection (image)

    Science.gov (United States)

    Leprosy is caused by the organism Mycobacterium leprae . The leprosy test involves injection of an antigen just under ... if your body has a current or recent leprosy infection. The injection site is labeled and examined ...

  2. 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.

  3. 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 ...

  4. 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.

  5. Antigen processing and remodeling of the endosomal pathway: requirements for antigen cross-presentation.

    Science.gov (United States)

    Compeer, Ewoud Bernardus; Flinsenberg, Thijs Willem Hendrik; van der Grein, Susanna Geertje; Boes, Marianne

    2012-01-01

    Cross-presentation of endocytosed antigen as peptide/class I major histocompatibility complex 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 capable of antigen cross-presentation, identification 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 highlights DC-intrinsic mechanisms that facilitate the cross-presentation of endocytosed antigen, including receptor-mediated uptake, maturation-induced endosomal sorting of membrane proteins, dynamic remodeling of endosomal structures and cell surface-directed endosomal trafficking. We will conclude with the description of pathogen-induced deviation of endosomal processing, and discuss how immune evasion strategies pertaining endosomal trafficking may preclude antigen cross-presentation.

  6. 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.

  7. 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

  8. Molecular cloning of cDNA for the human tumor-associated antigen CO-029 and identification of related transmembrane antigens

    International Nuclear Information System (INIS)

    Szala, S.; Kasai, Yasushi; Steplewski, Z.; Rodeck, U.; Koprowski, H.; Linnenbach, A.J.

    1990-01-01

    The human tumor-associated antigen CO-029 is a monoclonal antibody-defined cell surface glycoprotein of 27-34 kDa. By using the high-efficiency COS cell expression system, a full-length cDNA clone for CO-029 was isolated. When transiently expressed in COS cells, the cDNA clone directed the synthesis of an antigen reactive to monoclonal antibody CO-029 in mixed hemadsorption and immunoblot assays. Sequence analysis revealed that CO-029 belongs to a family of cell surface antigens that includes the melanoma-associated antigen ME491, the leukocyte cell surface antigen CD37, and the Sm23 antigen of the parasitic helminth Schistosoma mansoni. CO-029 and ME491 antigen expression and the effect of their corresponding monoclonal antibodies on cell growth were compared in human tumor cell lines of various histologic origins

  9. Isolation and structure of a cDNA encoding the B1 (CD20) cell-surface antigen of human B lymphocytes

    International Nuclear Information System (INIS)

    Tender, T.F.; Streuli, M.; Schlossman, S.F.; Saito, H.

    1988-01-01

    The B1 (CD20) molecule is a M/sub r/ 33,000 phosphoprotein on the surface of human B lymphocytes that may serve a central role in the homoral immune response by regulating B-cell proliferation and differentiation. In this report, a cDNA clone that encodes the B1 molecule was isolated and the amino acid sequence of B1 was determined. B-cell-specific cDNA clones were selected from a human tonsillar cDNA library by differential hybridization with labeled cDNA derived from either size-fractionated B-cell mRNA or size-fractionated T-cell mRNA. Of the 261 cDNA clones isolated, 3 cross-hybridizing cDNA clones were chosen as potential candidates for encoding B1 based on their selective hybridization to RNA from B1-positive cell lines. The longest clone, pB1-21, contained a 2.8-kilobase insert with an 891-base-pair open reading frame that encodes a protein of 33 kDa. mRNA synthesized from the pB1-21 cDNA clone in vitro was translated into a protein of the same apparent molecular weight as B1. Limited proteinase digestion of the pB1-21 translation product and B1 generated peptides of the same sizes, indicating that the pB1-21 cDNA encodes the B1 molecule. Gel blot analysis indicated that pB1-21 hybridized with two mRNA species of 2.8 and 3.4 kilobases only in B1-positive cell lines. The amino acid sequence deduced from the pB1-21 nucleotide sequence apparently lacks a signal sequence and contains three extensive hydrophobic regions. The deduced B1 amino acid sequence shows no significant homology with other known patients

  10. Coinfection of hepatic cell lines with human immunodeficiency virus and hepatitis B virus leads to an increase in intracellular hepatitis B surface antigen.

    Science.gov (United States)

    Iser, David M; Warner, Nadia; Revill, Peter A; Solomon, Ajantha; Wightman, Fiona; Saleh, Suha; Crane, Megan; Cameron, Paul U; Bowden, Scott; Nguyen, Tin; Pereira, Cândida F; Desmond, Paul V; Locarnini, Stephen A; Lewin, Sharon R

    2010-06-01

    Liver-related mortality is increased in the setting of HIV-hepatitis B virus (HBV) coinfection. However, interactions between HIV and HBV to explain this observation have not been described. We hypothesized that HIV infection of hepatocytes directly affects the life cycle of HBV. We infected human hepatic cell lines expressing HBV (Hep3B and AD38 cells) or not expressing HBV (Huh7, HepG2, and AD43 cells) with laboratory strains of HIV (NL4-3 and AD8), as well as a vesicular stomatitis virus (VSV)-pseudotyped HIV expressing enhanced green fluorescent protein (EGFP). Following HIV infection with NL4-3 or AD8 in hepatic cell lines, we observed a significant increase in HIV reverse transcriptase activity which was infectious. Despite no detection of surface CD4, CCR5, and CXCR4 by flow cytometry, AD8 infection of AD38 cells was inhibited by maraviroc and NL4-3 was inhibited by AMD3100, demonstrating that HIV enters AD38 hepatic cell lines via CCR5 or CXCR4. High-level infection of AD38 cells (50%) was achieved using VSV-pseudotyped HIV. Coinfection of the AD38 cell line with HIV did not alter the HBV DNA amount or species as determined by Southern blotting or nucleic acid signal amplification. However, coinfection with HIV was associated with a significant increase in intracellular HBsAg when measured by Western blotting, quantitative HBsAg, and fluorescence microscopy. We conclude that HIV infection of HBV-infected hepatic cell lines significantly increased intracellular HBsAg but not HBV DNA synthesis and that increased intrahepatic HBsAg secondary to direct infection by HIV may contribute to accelerated liver disease in HIV-HBV-coinfected individuals.

  11. 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.

  12. 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)

  13. 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...... molecules are the questions discussed in this review. To us, the entire concept of processing has appeal not only because it explains some hitherto well-established, but poorly understood, phenomena such as the fact that T lymphocytes focus their attention entirely upon antigens on other cells. It has...

  14. 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.

  15. Variation in the immune responses against Plasmodium falciparum merozoite surface protein-1 and apical membrane antigen-1 in children residing in the different epidemiological strata of malaria in Cameroon.

    Science.gov (United States)

    Kwenti, Tebit Emmanuel; Moye, Adzemye Linus; Wiylanyuy, Adzemye Basil; Njunda, Longdoh Anna; Nkuo-Akenji, Theresa

    2017-11-09

    Studies to assess the immune responses against malaria in Cameroonian children are limited. The purpose of this study was to assess the immune responses against Plasmodium falciparum merozoite surface protein-1 (MSP-1 19 ) and apical membrane antigen-1 (AMA-1) in children residing in the different epidemiological strata of malaria in Cameroon. In a cross-sectional survey performed between April and July 2015, 602 children between 2 and 15 years (mean ± SD = 5.7 ± 3.7), comprising 319 (53%) males were enrolled from five epidemiological strata of malaria in Cameroon including: the sudano-sahelian (SS) strata, the high inland plateau (HIP) strata, the south Cameroonian equatorial forest (SCEF) strata, the high western plateau (HWP) strata, and the coastal (C) strata. The children were screened for clinical malaria (defined by malaria parasitaemia ≥ 5000 parasites/µl plus axillary temperature ≥ 37.5 °C). Their antibody responses were measured against P. falciparum MSP-1 19 and AMA-1 vaccine candidate antigens using standard ELISA technique. A majority of the participants were IgG responders 72.1% (95% CI 68.3-75.6). The proportion of responders was higher in females (p = 0.002) and in children aged 10 years and above (p = 0.005). The proportion of responders was highest in Limbe (C strata) and lowest in Ngaoundere (HIP strata) (p malaria (p malaria parasites. The immune responses varied considerably across the different strata: the highest levels observed in the C strata and the lowest in the HIP strata. Furthermore, malaria transmission in Cameroon could be categorized into two major groups based on the serological reaction of the children: the southern (comprising C and SCEF strata) and northern (comprising HWP, HIP and SS strata) groups. These findings may have significant implications in the design of future trials for evaluating malaria vaccine candidates in Cameroon.

  16. 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.

  17. 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). ...

  18. 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.

  19. Antigen detection systems

    Science.gov (United States)

    Infectious agents or their constituent parts (antigens or nucleic acids) can be detected in fresh, frozen, or fixed tissues or other specimens, using a variety of direct or indirect assays. The assays can be modified to yield the greatest sensitivity and specificity but in most cases a particular m...

  20. Isocyanate test antigens

    International Nuclear Information System (INIS)

    Karol, M.H.; Alarie, Y.C.

    1980-01-01

    A test antigen for detecting antibodies to a diisocyanate comprises the reaction product of a protein and a monoisocyanate derived from the same radical as the diisocyanate. The diisocyanates most usually encountered and therefore calling for antibody detection are those of toluene, hexamethylene, methylene, isophorone and naphthylene. The preferred protein is human serum albumin. (author)

  1. 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.)

  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. Antigenic evaluation of a recombinant baculovirus-expressed Sarcocystis neurona SAG1 antigen.

    Science.gov (United States)

    Gupta, G D; Lakritz, J; Saville, W J; Livingston, R S; Dubey, J P; Middleton, J R; Marsh, A E

    2004-10-01

    Sarcocystis neurona is the primary parasite associated with equine protozoal myeloencephalitis (EPM). This is a commonly diagnosed neurological disorder in the Americas that infects the central nervous system of horses. Current serologic assays utilize culture-derived parasites as antigen. This method requires large numbers of parasites to be grown in culture, which is labor intensive and time consuming. Also, a culture-derived whole-parasite preparation contains conserved antigens that could cross-react with antibodies against other Sarcocystis species and members of Sarcocystidae such as Neospora spp., Hammondia spp., and Toxoplasma gondii. Therefore, there is a need to develop an improved method for the detection of S. neurona-specific antibodies. The sera of infected horses react strongly to surface antigen 1 (SnSAG1), an approximately 29-kDa protein, in immunoblot analysis, suggesting that it is an immunodominant antigen. The SnSAG1 gene of S. neurona was cloned, and recombinant S. neurona SAG1 protein (rSnSAG1-Bac) was expressed with the use of a baculovirus system. By immunoblot analysis, the rSnSAG1-Bac antigen detected antibodies to S. neurona from naturally infected and experimentally inoculated equids, cats, rabbit, mice, and skunk. This is the first report of a baculovirus-expressed recombinant S. neurona antigen being used to detect anti-S. neurona antibodies in a variety of host species.

  4. 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.

  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. Deteksi Antigen pada Kriptokokosis

    Directory of Open Access Journals (Sweden)

    Robiatul Adawiyah

    2014-12-01

    Full Text Available AbstrakKriptokokosis merupakan infeksi sistemik yang disebabkan Cryptococcus sp. Predileksi jamur tersebut adalah susunan saraf pusat dan selaput otak. Terdapat 5 spesies Cryptococcus sp. yang menyebabkan penyakit pada manusia; yang paling banyak adalah Cr. neoformans dan Cr. gattii. Diagnosis kriptokokosis ditegakkan berdasarkan gejala klinis, pemeriksaan laboratoris serta radiologis. Pemeriksaan laboratoris dilakukan dengan identifikasi morfologi, serologi danPCR. Pemeriksaan secara morfologi dengan tinta India positif  bila jumlah sel jamur 10  sel/ml spesimen. Kultur dilakukan di media sabouraud dextrose agar (SDA dan niger sheed agar (NSA, jamur tumbuh setelah 5-7 hari. Deteksi antigen dan antibodi dilakukan pada cairan tubuh dan tidak membutuhkan waktu lama. Deteksi antibodi Cr.neoformans memiliki kelemahan yaitu tidak menunjukkan hasil positif pada infeksi akut, IgA masih positif setelah 1-2 tahun fase penyembuhan, IgG dapat persisten, pada individu imunokompromis menunjukkan hasil yang sangat kompleks dan dalam menentukan diagnosis sering tidak konsisten. Polisakarida adalah komponen paling berperan dalam virulensi Cr. neoformans. Komponen polisakarida terutama glucuronoxylomannan merupakan petanda penting dalam diagnosis kriptokokosis secara serologis. Deteksi antigen Cr. neoformans memiliki kelebihan yaitu menunjukkan hasil positif pada infeksi akut/kronis, sensitivitas dan spesifisitas tinggi, dapat mendeteksi polisakarida hingga 10 ng/ml sehingga dengan kadarantigen yang minimal tetap dapat mendiagnosis kriptokokosis.Kata kunci: Cr. neoformans, glucuronoxylomannan, antigenAbstractCryptococcosis is systemic infection that caused by Cryptococcus sp. Predilection of this fungi is the central nervous system and brain membrane. There are 5 species of Cryptococcus sp. that cause cryptococcosis in human; but the majority are caused by Cr. neoformans and Cr. gattii. The diagnosis of cryptococcosis is made based on clinical symptoms

  7. Radioimmunoassay for hepatitis B core antigen

    International Nuclear Information System (INIS)

    Sagnelli, E.; Pereira, C.; Triolo, G.; Vernace, S.; Paronetto, F.

    1982-01-01

    Serum hepatitis B core antigen (HBcAg) is an important marker of hepatitis B virus replication. We describe an easy, sensitive radioimmunoassay for determination of HBcAg in detergent-treated serum pellets containing Dane particles. Components of a commercial kit for anticore determination are used, and HBcAG is measured by competitive inhibition of binding of 125 I-labeled antibodies to HBcAg with HBcAg-coated beads. We assayed for HBcAG in the sera of 49 patients with hepatitis B surface antigen (HBsAg)-positive chronic hepatitis, 50 patients with HBsAg-negative chronic hepatitis, and 30 healthy volunteers. HBcAg was detected in 41% of patients with HBsAg-positive chronic hepatitis but not in patients with HBsAg-negative chronic hepatitis. Hepatitis Be antigen (an antigen closely associated with the core of Dane particles) determined in the same sera by radioimmunoassay, was not detected in 50% of HBcAg-positive sera

  8. Carcino-Embryonic Antigen

    International Nuclear Information System (INIS)

    Akute, O.

    1999-02-01

    Tumour marker analysis has increased our understanding of the presence of tumours in the body. Carcino-embryonic antigen, CEA, is one of the best studied tumour markers and has proved an ideal diagnostic adjuvant. It has helped in quantifying the amount of disease present in a patient and thence to make accurate prognosis on the various diagnosed ailments. At UCH, it is observed that there is an increase in cancer related ailments and therefore the need for early diagnosis is more compelling in our environment to mitigate future cost of managing advanced manifestation

  9. Characterization of Antigen-Specific B Cells Using Nominal Antigen-Coated Flow-Beads

    Science.gov (United States)

    Akl, Ahmed; Lepetit, Maud; Crochette, Romain; Giral, Magali; Lepourry, Julie; Pallier, Annaick; Castagnet, Stéphanie; Dugast, Emilie; Guillot-Gueguen, Cécile; Jacq-Foucher, Marylène; Saulquin, Xavier; Cesbron, Anne; Laplaud, David; Nicot, Arnaud; Brouard, Sophie; Soulillou, Jean-Paul

    2013-01-01

    In order to characterize the reactivity of B cells against nominal antigens, a method based on the coupling of antigens onto the surface of fluorescent core polystyrene beads was developed. We first demonstrate that murine B cells with a human MOG-specific BCR are able to interact with MOG-coated beads and do not recognize beads coated with human albumin or pp65. B cells purified from human healthy volunteer blood or immunized individuals were tested for their ability to interact with various nominal antigens, including viral, vaccine, self and alloantigens, chosen for their usefulness in studying a variety of pathological processes. A substantial amount of B cells binding self-antigen MOG-coated beads can be detected in normal blood. Furthermore, greater frequencies of B cell against anti-Tetanic Toxin or anti-EBNA1 were observed in primed individuals. This method can reveal increased frequencies of anti-HLA committed B cells in patients with circulating anti-HLA antibodies compared to unsensitized patients and normal individuals. Of interest, those specific CD19 cells were preferentially identified within CD27−IgD+ (i-e naïve) subset. These observations suggest that a broad range of medical situations could benefit from a tool that allows the detection, the quantification and the characterization of antigen-specific blood B cells. PMID:24386360

  10. Limited antigenic variation in the Trypanosoma cruzi candidate vaccine antigen TSA-1.

    Science.gov (United States)

    Knight, J M; Zingales, B; Bottazzi, M E; Hotez, P; Zhan, B

    2014-12-01

    Chagas disease (American trypanosomiasis caused by Trypanosoma cruzi) is one of the most important neglected tropical diseases in the Western Hemisphere. The toxicities and limited efficacies of current antitrypanosomal drugs have prompted a search for alternative technologies such as a therapeutic vaccine comprised of T. cruzi antigens, including a recombinant antigen encoding the N-terminal 65 kDa portion of Trypomastigote surface antigen-1 (TSA-1). With at least six known genetically distinct T. cruzi lineages, variability between the different lineages poses a unique challenge for the development of broadly effective therapeutic vaccine. The variability across the major lineages in the current vaccine candidate antigen TSA-1 has not previously been addressed. To assess the variation in TSA-1, we cloned and sequenced TSA-1 from several different T. cruzi strains representing three of the most clinically relevant lineages. Analysis of the different alleles showed limited variation in TSA-1 across the different strains and fit with the current theory for the evolution of the different lineages. Additionally, minimal variation in known antigenic epitopes for the HLA-A 02 allele suggests that interlineage variation in TSA-1 would not impair the range and efficacy of a vaccine containing TSA-1. © 2014 John Wiley & Sons Ltd.

  11. 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...

  12. 78 FR 13691 - Prospective Grant of Exclusive License: The Development of m971 and m972 Chimeric Antigen...

    Science.gov (United States)

    2013-02-28

    ... Exclusive License: The Development of m971 and m972 Chimeric Antigen Receptors (CARs) for the Treatment of B... ``M971 Chimeric Antigen Receptors'' [HHS Ref. E-291-2012/0-US-01], and (b) U.S. Patent Application 61/042... malignancies that express CD22 on their cell surface using chimeric antigen receptors which contain the m971 or...

  13. 77 FR 62520 - Prospective Grant of Exclusive License: The Development of Anti-CD22 Chimeric Antigen Receptors...

    Science.gov (United States)

    2012-10-15

    ... Exclusive License: The Development of Anti- CD22 Chimeric Antigen Receptors (CARs) for the Treatment of B... ``Anti-CD22 Chimeric Antigen Receptors'' [HHS Ref. E-265-2011/0-US-01], and (b) U.S. Patent Application... CD22 on their cell surface using chimeric antigen receptors which contain the HA22 or BL22 antibody...

  14. 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...

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. Oncogenic cancer/testis antigens

    DEFF Research Database (Denmark)

    Gjerstorff, Morten F; Andersen, Mads H; Ditzel, Henrik J

    2015-01-01

    Recent developments have set the stage for immunotherapy as a supplement to conventional cancer treatment. Consequently, a significant effort is required to further improve efficacy and specificity, particularly the identification of optimal therapeutic targets for clinical testing. Cancer....../testis antigens are immunogenic, highly cancer-specific, and frequently expressed in various types of cancer, which make them promising candidate targets for cancer immunotherapy, including cancer vaccination and adoptive T-cell transfer with chimeric T-cell receptors. Our current understanding of tumor...... immunology and immune escape suggests that targeting oncogenic antigens may be beneficial, meaning that identification of cancer/testis antigens with oncogenic properties is of high priority. Recent work from our lab and others provide evidence that many cancer/testis antigens, in fact, have oncogenic...

  20. 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.

  1. Anvendelse af prostataspecifikt antigen. En oversigt

    DEFF Research Database (Denmark)

    Brasso, K; Skaarup, P; Roosen, Jens Ulrik

    1998-01-01

    Since it was first introduced, measurement of prostate specific antigen has gained increasing interest, and prostate specific antigen is regarded as being the best tumour marker available. The antigen lacks cancer specificity, limiting the usefulness in early diagnosis, The use of prostate specific...... antigen in early diagnosis, staging, and in monitoring patients with prostate cancer is reviewed....

  2. Keratin, luminal epithelial antigen and carcinoembryonic antigen in human urinary bladder carcinomas. An immunohistochemical study.

    Science.gov (United States)

    Nathrath, W B; Arnholdt, H; Wilson, P D

    1982-01-01

    14 urinary bladder carcinomas of all main types were investigated with antisera to "broad spectrum keratin" (aK), "luminal epithelial antigen" (aLEA) and carcinoembryonic antigen (aCEA), using an indirect immunoperoxidase method on formalin fixed paraffin embedded sections. Keratin and LEA were both present in normal transitional epithelium, papilloma and carcinoma in situ whereas CEA was absent. Transitional cell carcinomas reacted with both aK and aLEA whereas CEA was seen only in a few foci. In squamous metaplasia and squamous carcinoma reaction with aK was particularly strong, while LEA was almost lacking and CEA was present in necrotic centres. In adenocarcinomas aK and aLEA reacted equally while aCEA reacted only on the surface.

  3. 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.

  4. 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...

  5. Characterization of plant plasma membrane antigens: [Annual] progress report

    International Nuclear Information System (INIS)

    Galbraith, D.W.; Afonso, C.L.; Meyer, D.; Harkins, K.R.

    1987-01-01

    Protoplast plasma membranes were used to raise antibodies in mice to cell surface antigens. Monoclonal antibodies were selected from those produced and used for indirect immunofluorescence microscopic analysis of N. tabacum cells. In parallel studies cDNA expression libraries were prepared. (DT)

  6. The distribution of blood group antigens in experimentally produced carcinomas of rat palate

    DEFF Research Database (Denmark)

    Reibel, J; Philipsen, H P; Fisker, A V

    1986-01-01

    palate induced by a chemical carcinogen (4NQO). The H antigen, normally expressed on spinous cells in rats, was absent in malignant epithelium, whereas staining for the B antigen, normally expressed on basal cells, was variable. These changes are equivalent to those seen in human squamous cell carcinomas....... The blood group antigen staining pattern in experimentally produced verrucous carcinomas showed an almost normal blood group antigen expression. This may have diagnostic significance. Localized areas of hyperplastic palatal epithelium with slight dysplasia revealed loss of H antigen and the presence of B...... antigen in suprabasal strata equivalent to the pattern seen in human premalignant epithelium. We conclude from these findings, that the rat model is well suited to study changes in cell surface carbohydrates during chemical carcinogenesis....

  7. Chemoselective ligation and antigen vectorization.

    Science.gov (United States)

    Gras-Masse, H

    2001-01-01

    The interest in cocktail-lipopeptide vaccines has now been confirmed by phase I clinical trials: highly diversified B-, T-helper or cytotoxic T-cell epitopes can be combined with a lipophilic vector for the induction of B- and T-cell responses of predetermined specificity. With the goal of producing an improved vaccine that should ideally induce a multispecific response in non-selected populations, increasing the diversity of the immunizing mixture represents one of the most obvious strategies.The selective delivery of antigens to professional antigen-presenting cells represents another promising approach for the improvement of vaccine efficacy. In this context, the mannose-receptor represents an attractive entry point for the targeting to dendritic cells of antigens linked to clustered glycosides or glycomimetics. In all cases, highly complex but fully characterized molecules must be produced. To develop a modular and flexible strategy which could be generally applicable to a large set of peptide antigens, we elected to explore the potentialities of chemoselective ligation methods. The hydrazone bond was found particularly reliable and fully compatible with sulphide ligation. Hydrazone/thioether orthogonal ligation systems could be developed to account for the nature of the antigens and the solubility of the vector systems. Copyright 2001 The International Association for Biologicals.

  8. Rapid desensitization induces internalization of antigen-specific IgE on mouse mast cells.

    Science.gov (United States)

    Oka, Tatsuya; Rios, Eon J; Tsai, Mindy; Kalesnikoff, Janet; Galli, Stephen J

    2013-10-01

    Rapid desensitization transiently prevents severe allergic reactions, allowing administration of life-saving therapies in previously sensitized patients. However, the mechanisms underlying successful rapid desensitization are not fully understood. We sought to investigate whether the mast cell (MC) is an important target of rapid desensitization in mice sensitized to exhibit IgE-dependent passive systemic anaphylaxis in vivo and to investigate the antigen specificity and underlying mechanisms of rapid desensitization in our mouse model. C57BL/6 mice (in vivo) or primary isolated C57BL/6 mouse peritoneal mast cells (PMCs; in vitro) were passively sensitized with antigen-specific anti-2,4-dinitrophenyl IgE, anti-ovalbumin IgE, or both. MCs were exposed over a short period of time to increasing amounts of antigen (2,4-dinitrophenyl-human serum albumin or ovalbumin) in the presence of extracellular calcium in vitro or by means of intravenous administration to sensitized mice in vivo before challenging the mice with or exposing the PMCs to optimal amounts of specific or irrelevant antigen. Rapidly exposing mice or PMCs to progressively increasing amounts of specific antigen inhibited the development of antigen-induced hypothermia in sensitized mice in vivo and inhibited antigen-induced PMC degranulation and prostaglandin D2 synthesis in vitro. Such MC hyporesponsiveness was induced antigen-specifically and was associated with a significant reduction in antigen-specific IgE levels on MC surfaces. Rapidly exposing MCs to progressively increasing amounts of antigen can both enhance the internalization of antigen-specific IgE on the MC surface and also desensitize these cells in an antigen-specific manner in vivo and in vitro. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

  9. 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.

  10. Effect of radiation on the expression of tumor-associated antigens of human lung adenocarcinoma cells. Immunological study using monoclonal antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Hareyama, Masato

    1988-12-01

    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-..gamma... 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/sub 2//M phases of the cell cycle than in G/sub 0//G/sub 1/. The expression of YH206 antigen was enhanced in the S and G/sub 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.

  11. Selective elution of HLA antigens and beta 2-microglobulin from human platelets by chloroquine diphosphate

    International Nuclear Information System (INIS)

    Kao, K.J.

    1988-01-01

    To determine whether chloroquine can specifically elute HLA antigens and beta 2-microglobulin (beta 2-M) from the platelet surface, quantitative immunofluorescence flow cytometry and monoclonal antibodies were used to show that HLA antigens and beta 2-M were proportionally eluted from the platelet surface without affecting the membrane glycoproteins IIb and IIIa. Second, an autoradiogram of electrophoresed I-125-labeled platelets showed that only beta 2-M but not other I-125-labeled membrane proteins could be eluted. Although HLA antigens were poorly labeled by I-125 and could not be detected on the autoradiogram, the eluted HLA antigens could be detected by anti-HLA monoclonal antibody and immunoblotting techniques. No loss of plasma membrane integrity was observed by transmission electron microscopy after chloroquine treatment of platelets. The results indicate that chloroquine selectively elutes HLA antigens and their noncovalently associated beta 2-M without affecting other integral platelet membrane proteins

  12. Dichotomy of the human T cell response to Leishmania antigens. I. Th1-like response to Leishmania major promastigote antigens in individuals recovered from cutaneous leishmaniasis

    DEFF Research Database (Denmark)

    Kemp, M; Hey, A S; Kurtzhals, J A

    1994-01-01

    of skin lesions, and in Danes without known exposure to Leishmania parasites. Proliferation and production of interferon-gamma (IFN-gamma) and IL-4 in antigen-stimulated cultures was measured. Lymphocytes from individuals with a history of CL proliferated vigorously and produced IFN-gamma after...... the unexposed Danes were not activated by gp63. The cells from Danish donors produced either IFN-gamma or IL-4, but not both cytokines after incubation with the crude preparation of L. major antigens. The data show that the T cell response to Leishmania antigens in humans who have had uncomplicated CL...... stimulation with either a crude preparation of L. major antigens or the major surface protease gp63. These cultures produced no or only little IL-4. Also cells from leishmanin skin test-positive donors with no history of CL produced IFN-gamma and no IL-4 in response to L. major antigens. Cells from...

  13. [Limbic encephalitis with antibodies against intracellular antigens].

    Science.gov (United States)

    Morita, Akihiko; Kamei, Satoshi

    2010-04-01

    Limbic encephalitis is a paraneoplastic syndrome that is often associated with small cell lung cancer (SCLC), breast cancer, testicular tumors, teratoma, Hodgkin's lymphoma and thymoma. The common clinical manifestations of limbic encephalitis are subacute onset, cognitive dysfunction, seizures and psychiatric symptoms. Paraneoplastic neurological disorders are considered to occur because of cytotoxic T cell responses and antibodies against target neuronal proteins that are usually expressed by an underlying tumor. The main intracellular antigens related to limbic encephalitis are Hu, Ma2, and less frequently CV2/CRMP5 and amphiphysin. The anti-Hu antibody, which is involved in cerebellar degeneration and extensive or multifocal encephalomyelitis such as limbic encephalitis is closely associated with a history of smoking and SCLC. The anti-Ma2 antibody is associated with encephalitis of the limbic system, hypothalamus and brain-stem. For this reason, some patients with limbic encephalitis have sleep disorders (including REM sleep abnormalities), severe hypokinesis and gaze palsy in addition to limbic dysfunction. In men aged less than 50 years, anti-Ma2 antibody encephalitis is almost always associated with testicular germ-cell tumors that are occasionally difficult to detect. In older men and women, the most common tumors are non-SCLC and breast cancer. Limbic encephalitis associated with cell-surface antigens (e.g., voltage-gated potassium channels, NMDA receptors) is mediated by antibodies and often improves after a reduction in the antibody titer and after tumor resection. Patients with antibodies against intracellular antigens, except for those with anti-Ma2 antibodies and testicular tumors, are less responsive. Early diagnosis and treatment with immunotherapy, tumor resection or both are important for improving or stabilizing the condition of limbic encephalitis.

  14. Distribution of 125I-monoclonal antibodies to antigen Ly 2.1 of T-lymphocytes in mice under the influence of immunomodulators

    International Nuclear Information System (INIS)

    Mirolyubova, Sh.Yu.; Fadeev, N.P.; Serzhanina, V.A.; Klimovich, V.B.; Makarenko, M.V.; Korsakova, L.N.

    1991-01-01

    A study was made of the distribution of 125 I (a chloramine method of labelling) monoclonal antibodies to the surface antigen Ly 2.1 T-lymphocytes during action of immunomodulators (tactivin, hydrocortisone, tactivin administered after hydrocortisone) on ACR mice. These antibodies were shown to retain antigen binding capacity, permitting monitoring of the redistribution of the antigen in the body exposed to immunomodulators

  15. 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

  16. 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

  17. Effect of antigen shedding on targeted delivery of immunotoxins in solid tumors from a mathematical model.

    Directory of Open Access Journals (Sweden)

    Youngshang Pak

    Full Text Available Most cancer-specific antigens used as targets of antibody-drug conjugates and immunotoxins are shed from the cell surface (Zhang & Pastan (2008 Clin. Cancer Res. 14: 7981-7986, although at widely varying rates and by different mechanisms (Dello Sbarba & Rovida (2002 Biol. Chem. 383: 69-83. Why many cancer-specific antigens are shed and how the shedding affects delivery efficiency of antibody-based protein drugs are poorly understood questions at present. Before a detailed numerical study, it was assumed that antigen shedding would reduce the efficacy of antibody-drug conjugates and immunotoxins. However, our previous study using a comprehensive mathematical model showed that antigen shedding can significantly improve the efficacy of the mesothelin-binding immunotoxin, SS1P (anti-mesothelin-Fv-PE38, and suggested that receptor shedding can be a general mechanism for enhancing the effect of inter-cellular signaling molecules. Here, we improved this model and applied it to both SS1P and another recombinant immunotoxin, LMB-2, which targets CD25. We show that the effect of antigen shedding is influenced by a number of factors including the number of antigen molecules on the cell surface and the endocytosis rate. The high shedding rate of mesothelin is beneficial for SS1P, for which the antigen is large in number and endocytosed rapidly. On the other hand, the slow shedding of CD25 is beneficial for LMB-2, for which the antigen is small in number and endocytosed slowly.

  18. Splenic B cells and antigen-specific B cells process anti-Ig in a similar manner

    International Nuclear Information System (INIS)

    Myers, C.D.; Vitetta, E.S.

    1989-01-01

    B lymphocytes can process and present antigen to T cells. However, the fate of native antigen after its binding to specific B cells, i.e., the intracellular events involved in the processing and recycling of the antigenic fragments to the cell surface for antigen presentation, are not well understood. In the present study, we demonstrate that murine B cells degrade anti-Ig molecules bound to their surface and release acid soluble fragments into the supernatant. We also demonstrate that the kinetics of this process are identical for anti-mu, anti-delta, and anti-light chain antibodies, indicating that both surface IgM and surface IgD are equally effective in binding antigen and directing its processing. We also describe the effects of azide, chloroquine, and irradiation on this process. To extend these studies to the processing of specifically bound antigen, we demonstrate that highly purified trinitrophenyl antigen-binding cells degrade anti-Ig molecules with the same kinetics as unpurified splenic B cells. Thus, this purified population provides a suitable model system for the analysis of antigen degradation by antigen-specific cells

  19. Antigenic determinants and functional domains in core antigen and e antigen from hepatitis B virus

    International Nuclear Information System (INIS)

    Salfeld, J.; Pfaff, E.; Noah, M.; Schaller, H.

    1989-01-01

    The precore/core gene of hepatitis B virus directs the synthesis of two polypeptides, the 21-kilodalton subunit (p21c) forming the viral nucleocapsid (serologically defined as core antigen [HBcAg]) and a secreted processed protein (p17e, serologically defined as HBe antigen [HBeAg]). Although most of their primary amino acid sequences are identical, HBcAg and HBeAg display different antigenic properties that are widely used in hepatitis B virus diagnosis. To locate and to characterize the corresponding determinants, segments of the core gene were expressed in Escherichia coli and probed with a panel of polyclonal or monoclonal antibodies in radioimmunoassays or enzyme-linked immunosorbent assays, Western blots, and competition assays. Three distinct major determinants were characterized. It is postulated that HBcAg and HBeAg share common basic three-dimensional structure exposing the common linear determinant HBe1 but that they differ in the presentation of two conformational determinants that are either introduced (HBc) or masked (HBe2) in the assembled core. The simultaneous presentation of HBe1 and HBc, two distinctly different antigenic determinants with overlapping amino acid sequences, is interpreted to indicate the presence of slightly differently folded, stable conformational states of p21c in the hepatitis virus nucleocapsid

  20. Detection and quantification of Duffy antigen on bovine red blood cell membranes using a polyclonal antibody

    Directory of Open Access Journals (Sweden)

    Ana Teresa B.F. Antonangelo

    2012-09-01

    Full Text Available Babesiosis is one of the most important diseases affecting livestock agriculture worldwide. Animals from the subspecies Bos taurus indicus are more resistant to babesiosis than those from Bos taurus taurus. The genera Babesia and Plasmodium are Apicomplexa hemoparasites and share features such as invasion of red blood cells (RBC. The glycoprotein Duffy is the only human erythrocyte receptor for Pasmodium vivax and a mutation which abolishes expression of this glycoprotein on erythrocyte surfaces is responsible for making the majority of people originating from the indigenous populations of West Africa resistant to P. vivax. The current work detected and quantified the Duffy antigen on Bos taurus indicus and Bos taurus taurus erythrocyte surfaces using a polyclonal antibody in order to investigate if differences in susceptibility to Babesia are due to different levels of Duffy antigen expression on the RBCs of these animals, as is known to be the case in human beings for interactions of Plasmodium vivax-Duffy antigen. ELISA tests showed that the antibody that was raised against Duffy antigens detected the presence of Duffy antigen in both subspecies and that the amount of this antigen on those erythrocyte membranes was similar. These results indicate that the greater resistance of B. taurus indicus to babesiosis cannot be explained by the absence or lower expression of Duffy antigen on RBC surfaces.

  1. Antigen presentation by hapten-specific B lymphocytes. II. Specificity and properties of antigen-presenting B lymphocytes, and function of immunoglobulin receptors

    International Nuclear Information System (INIS)

    Abbas, A.K.; Haber, S.; Rock, K.L.

    1985-01-01

    Studies were designed to examine the ability of hapten-binding murine B lymphocytes to present hapten-protein conjugates to protein antigen-specific, Ia-restricted T cell hybridomas. BALB/c B cells specific for TNP or FITC presented hapten-modified proteins (TNP-G1 phi, TNP-OVA, or FITC-OVA) to the relevant T cell hybridomas at concentrations below 0.1 microgram/ml. Effective presentation of the same antigens by B lymphocyte-depleted splenocytes, and of unmodified proteins by either hapten-binding B cells or Ig spleen cells, required about 10(3)-to 10(4)-fold higher concentrations of antigen. The use of two different haptens and two carrier proteins showed that this extremely efficient presentation of antigen was highly specific, with hapten specificity being a property of the B cells and carrier specificity of the responding T cells. The presentation of hapten-proteins by hapten-binding B lymphocytes was radiosensitive and was not affected by the depletion of plastic-adherent cells, suggesting that conventional APCs (macrophages or dendritic cells) are not required in this phenomenon. Antigen-pulsing and antibody-blocking experiments showed that this hapten-specific antigen presentation required initial binding of antigen to surface Ig receptors. Moreover, linked recognition of hapten and carrier determinants was required, but these recognition events could be temporally separated. Finally, an antigen-processing step was found to be necessary, and this step was disrupted by ionizing radiation. These data suggest a role for B cell surface Ig in providing a specific high-affinity receptor to allow efficient uptake or focusing of antigen for its subsequent processing and presentation to T lymphocytes

  2. 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

  3. Radioprotective activity of shigella antigens

    International Nuclear Information System (INIS)

    Klemparskaya, N.N.; Gorbunova, E.S.; Dobronravova, N.N.

    1981-01-01

    The possibility of using experimental microbe antigenous preparation out of Flexner and Zonne shigellas as a protector and a remedy in the case of gamma irradiation, is investigated. The experiments are carried out on mice of both sexes immunized before or after irradiation by two methods: subcutaneously and enerally. It is found that in most cases investigated, the introduction of the experimental preparation 3, 5, 7 and 10 days before irradiation increases the survivability of animals [ru

  4. 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

  5. Novel Treponema pallidum Recombinant Antigens for Syphilis Diagnostics: Current Status and Future Prospects

    Directory of Open Access Journals (Sweden)

    Aleksey Kubanov

    2017-01-01

    Full Text Available 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.

  6. Novel Treponema pallidum Recombinant 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.

  7. 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.

  8. Chlorphenesin: an antigen-associated immunosuppressant.

    Science.gov (United States)

    Whang, H Y; Neter, E

    1970-07-01

    Chlorphenesin (3-p-chlorophenoxy-1,2-propanediol), when injected intravenously together with either of two common bacterial antigens, inhibits the antibody response of the rabbit. The antigens studied are those common to Enterobacteriaceae and to gram-positive bacteria. The immunosuppression is contingent upon incubation of chlorphenesin and antigen in vitro prior to administration, since separate injection of antigen and inhibitor or of mixtures without prior incubation yields undiminished antibody response. Chlorphenesin, as shown by hemagglutination-inhibition tests, does not alter the antigenic determinants, because antibody neutralization occurs in the presence or absence of the drug. The immunosuppressive effect is reversible, since precipitation of chlorphenesin at 4 C substantially restores immunogenicity. Animals immunized with antigen-drug mixtures, which fail to respond with significant antibody production, nonetheless are immunologically primed. It is concluded that chlorphenesin represents another example of antigen-associated immunosuppressants.

  9. Presentation of lipid antigens to T cells.

    Science.gov (United States)

    Mori, Lucia; De Libero, Gennaro

    2008-04-15

    T cells specific for lipid antigens participate in regulation of the immune response during infections, tumor immunosurveillance, allergy and autoimmune diseases. T cells recognize lipid antigens as complexes formed with CD1 antigen-presenting molecules, thus resembling recognition of MHC-peptide complexes. The biophysical properties of lipids impose unique mechanisms for their delivery, internalization into antigen-presenting cells, membrane trafficking, processing, and loading of CD1 molecules. Each of these steps is controlled at molecular and celular levels and determines lipid immunogenicity. Lipid antigens may derive from microbes and from the cellular metabolism, thus allowing the immune system to survey a large repertoire of immunogenic molecules. Recognition of lipid antigens facilitates the detection of infectious agents and the initiation of responses involved in immunoregulation and autoimmunity. This review focuses on the presentation mechanisms and specific recognition of self and bacterial lipid antigens and discusses the important open issues.

  10. 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.

  11. Reduction of T-Helper Cell Responses to Recall Antigen Mediated by Codelivery with Peptidoglycan via the Intestinal Nanomineral-Antigen Pathway.

    Science.gov (United States)

    Hewitt, Rachel E; Robertson, Jack; Haas, Carolin T; Pele, Laetitia C; Powell, Jonathan J

    2017-01-01

    Naturally occurring intestinal nanomineral particles constituently form in the mammalian gut and trap luminal protein and microbial components. These cargo loaded nanominerals are actively scavenged by M cells of intestinal immune follicles, such as Peyer's patches and are passed to antigen-presenting cells. Using peripheral blood mononuclear cell populations as an in vitro model of nanomineral uptake and antigen presentation, we show that monocytes avidly phagocytose nanomineral particles bearing antigen and peptidoglycan (PGN), and that the presence of PGN within particles downregulates their cell surface MHC class II and upregulates programmed death receptor ligand 1. Nanomineral delivery of antigen suppresses antigen-specific CD4 + T cell responses, an effect that is enhanced in the presence of PGN. Blocking the interleukin-10 receptor restores CD4 + T cell responses to antigen codelivered with PGN in nanomineral form. Using human intestinal specimens, we have shown that the in vivo nanomineral pathway operates in an interleukin-10 rich environment. Consequently, the delivery of a dual antigen-PGN cargo by endogenous nanomineral in vivo is likely to be important in the establishment of intestinal tolerance, while their synthetic mimetics present a potential delivery system for therapeutic applications targeting the modulation of Peyer's patch T cell responses.

  12. Common tree shrews and primates share leukocyte membrane antigens.

    Science.gov (United States)

    Palley, L S; Schlossman, S F; Letvin, N L

    1984-01-01

    Monoclonal antibodies reactive with human peripheral blood lymphocyte and myeloid cell surface antigens were utilized to study the phylogeny of the common tree shrew. Blood cells from the common tree shrew, but not the bat or short-tailed shrew, react with certain of these antibodies. These data strengthen the argument that the Tupaiidae are primitive primates rather than insectivores. They also indicate that this approach should be useful for further work in taxonomic systemization.

  13. 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

  14. Calorimetric comparison of the interactions between salivary proteins and Streptococcus mutans with and without antigen I/II

    NARCIS (Netherlands)

    Xu, C.P.; Belt-Gritter, van de B.; Busscher, H.J.; Mei, van der H.C.; Norde, W.

    2007-01-01

    Antigen I/II can be found on streptococcal cell surfaces and is involved in their interaction with salivary proteins. In this paper, we determine the adsorption enthalpies of salivary proteins to Streptococcus mutans LT11 and S. mutans IB03987 with and without antigen I/II, respectively, using

  15. Calorimetric comparison of the interactions between salivary proteins and Streptococcus mutans with and without antigen I/II

    NARCIS (Netherlands)

    Xu, Chun-Ping; Belt-Gritter, van de Betsy; Busscher, Henk J.; van der Mei, Henny C.; Norde, Willem

    2007-01-01

    Antigen I/II can be found on streptococcal cell surfaces and is involved in their interaction with salivary proteins. In this paper, we determine the adsorption enthalpies of salivary proteins to Streptococcus mutans LT 11 and S. mutans IB03987 with and without antigen I/II, respectively, using

  16. Characterization of a 14,000 dalton antigen of Dirofilaria immitis infective third stage larvae

    International Nuclear Information System (INIS)

    Fuller, S.A.; Cachia, P.J.; Wong, M.M.; Hurrell, J.G.R.

    1986-01-01

    Immunogenic proteins of Dirofilaria immitis (canine heartworm) were identified by probing extracts of adult worms or their excretory-secretory proteins (ESP) blotted to nitrocellulose following SDS-PAGE with control or infected dog sera. A 14,000 dalton antigen (a prominent component of ESP by protein staining) was consistently recognized both in extracts and ESP by dog sera as early as three months post infection. This indicates a larval origin for the antigen since no adult worms are present until approximately five months post infection. Monoclonal antibodies (MAbs) prepared against the 14,000 dalton antigen confirmed by immunoblotting that this antigen is expressed by infective third stage larvae, adults and microfilariae and is present intact in the sera of infected dogs. Surface-labelling of whole adult D. immitis with Na 125 I produced radiolabelled antigens closely corresponding to those of ESP. An anti-14,000 dalton MAb was able to immunoprecipitate radiolabelled antigen which strongly suggest a surface or membrane location in the intact organism. Gel filtration data suggests that the protein is a native monomer. A MAb-affinity column has been used to purify the 14,000 dalton antigen to at least 98% homogeneity in one step from crude worm extracts. Further fractionation by HPLC yields a homogeneous preparation. Amino acid analysis and the N-terminal amino acid sequence data will be presented

  17. Molecular cloning of complementary DNAs encoding the heavy chain of the human 4F2 cell-surface antigen: a type II membrane glycoprotein involved in normal and neoplastic cell growth

    International Nuclear Information System (INIS)

    Quackenbush, E.; Clabby, M.; Gottesdiener, K.M.; Barbosa, J.; Jones, N.H.; Strominger, J.L.; Speck, S.; Leiden, J.M.

    1987-01-01

    Complementary DNA (cDNA) clones encoding the heavy chain of the heterodimeric human membrane glycoprotein 4F2 have been isolated by immunoscreening of a λgt11 expression library. The identity of these clones has been confirmed by hybridization to RNA and DNA prepared from mouse L-cell transfectants, which were produced by whole cell gene transfer and selected for cell-surface expression of the human 4F2 heavy chain. DNA sequence analysis suggest that the 4F2 heavy-chain cDNAs encode an approximately 526-amino acid type II membrane glycoprotein, which is composed of a large C-terminal extracellular domain, a single potential transmembrane region, and a 50-81 amino acid N-terminal intracytoplasmic domain. Southern blotting experiments have shown that the 4F2 heavy-chain cDNAs are derived from a single-copy gene that has been highly conserved during mammalian evolution

  18. 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.

  19. 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}.

  20. 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.

  1. Characterization of Leishmania Soluble Exo-Antigen

    National Research Council Canada - National Science Library

    Cui, Liwang

    2003-01-01

    .... Vaccine development is the ultimate solution for this problem. Our previous research indicates that Leishmania parasites secrete, excrete, or shed antigens into the medium during in vitro culture...

  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. 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

  4. Mother-Newborn Pairs in Malawi Have Similar Antibody Repertoires to Diverse Malaria Antigens.

    Science.gov (United States)

    Boudová, Sarah; Walldorf, Jenny A; Bailey, Jason A; Divala, Titus; Mungwira, Randy; Mawindo, Patricia; Pablo, Jozelyn; Jasinskas, Algis; Nakajima, Rie; Ouattara, Amed; Adams, Matthew; Felgner, Philip L; Plowe, Christopher V; Travassos, Mark A; Laufer, Miriam K

    2017-10-01

    Maternal antibodies may play a role in protecting newborns against malaria disease. Plasmodium falciparum parasite surface antigens are diverse, and protection from infection requires allele-specific immunity. Although malaria-specific antibodies have been shown to cross the placenta, the extent to which antibodies that respond to the full repertoire of diverse antigens are transferred from the mother to the infant has not been explored. Understanding the breadth of maternal antibody responses and to what extent these antibodies are transferred to the child can inform vaccine design and evaluation. We probed plasma from cord blood and serum from mothers at delivery using a customized protein microarray that included variants of malaria vaccine target antigens to assess the intensity and breadth of seroreactivity to three malaria vaccine candidate antigens in mother-newborn pairs in Malawi. Among the 33 paired specimens that were assessed, mothers and newborns had similar intensity and repertoire of seroreactivity. Maternal antibody levels against vaccine candidate antigens were the strongest predictors of infant antibody levels. Placental malaria did not significantly impair transplacental antibody transfer. However, mothers with placental malaria had significantly higher antibody levels against these blood-stage antigens than mothers without placental malaria. The repertoire and levels of infant antibodies against a wide range of malaria vaccine candidate antigen variants closely mirror maternal levels in breadth and magnitude regardless of evidence of placental malaria. Vaccinating mothers with an effective malaria vaccine during pregnancy may induce high and potentially protective antibody repertoires in newborns. Copyright © 2017 American Society for Microbiology.

  5. Reduction of T-Helper Cell Responses to Recall Antigen Mediated by Codelivery with Peptidoglycan via the Intestinal Nanomineral–Antigen Pathway

    Science.gov (United States)

    Hewitt, Rachel E.; Robertson, Jack; Haas, Carolin T.; Pele, Laetitia C.; Powell, Jonathan J.

    2017-01-01

    Naturally occurring intestinal nanomineral particles constituently form in the mammalian gut and trap luminal protein and microbial components. These cargo loaded nanominerals are actively scavenged by M cells of intestinal immune follicles, such as Peyer’s patches and are passed to antigen-presenting cells. Using peripheral blood mononuclear cell populations as an in vitro model of nanomineral uptake and antigen presentation, we show that monocytes avidly phagocytose nanomineral particles bearing antigen and peptidoglycan (PGN), and that the presence of PGN within particles downregulates their cell surface MHC class II and upregulates programmed death receptor ligand 1. Nanomineral delivery of antigen suppresses antigen-specific CD4+ T cell responses, an effect that is enhanced in the presence of PGN. Blocking the interleukin-10 receptor restores CD4+ T cell responses to antigen codelivered with PGN in nanomineral form. Using human intestinal specimens, we have shown that the in vivo nanomineral pathway operates in an interleukin-10 rich environment. Consequently, the delivery of a dual antigen–PGN cargo by endogenous nanomineral in vivo is likely to be important in the establishment of intestinal tolerance, while their synthetic mimetics present a potential delivery system for therapeutic applications targeting the modulation of Peyer’s patch T cell responses. PMID:28367148

  6. Radioimmunoassay for a human prostate specific antigen

    International Nuclear Information System (INIS)

    Machida, T.; Miki, M.; Ohishi, Y.; Kido, A.; Morikawa, J.; Ogawa, Y.

    1983-01-01

    As a marker for prostatic cancer, a prostate-specific antigen was purified from human prostatic tissues. Double antibody radioimmunoassay utilizing immune reaction was developed on the basis of the purified prostatic antigen (PA). Measurement results have revealed that PA radioimmunoassay is much better than prostatic acid phosphatase (PAP) radioimmunoassay in the diagnosis of prostatic cancer

  7. [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.

  8. Studies on antigenic cross-reactivity of Trichuris ovis with host mucosal antigens in goat

    Directory of Open Access Journals (Sweden)

    Gautam Patra

    2015-12-01

    Full Text Available Objective: To ascertain whether immunodominant antigens of Trichuris ovis might share and cross react with host molecule. Methods: Two crude protein preparations from anterior and posterior parts of Trichuris ovis were characterized along with host mucosal antigen by double immunodiffusion, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotting technique. Conventional scanning electron microscopy was performed as per standard procedure. Results: Sharp and distinct bands of three antigens have been found in double immunodiffusion using hyperimmune serum raised in rabbit indicating the presence of specific antibody against each antigen. All three antigens have shown major and minor bands with molecular weight ranging from 15 to 110 kDa during sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Conclusions: The antigenic cross-reactivity was thought to result from shared antigens. The existence of paracloacal papillae found in the anterior part of the male was not a unique feature for species differentiation.

  9. Definition of a virulence-related antigen of Neisseria gonorrhoeae with monoclonal antibodies and lectins.

    Science.gov (United States)

    Demarco de Hormaeche, R; Bundell, C; Chong, H; Taylor, D W; Wildy, P

    1986-03-01

    Variants of one strain of Neisseria gonorrhoeae, grown in vivo or in vitro, that have been previously shown to differ in infectivity, serum resistance, and capsule production were compared with use of monoclonal antibodies and lectins. Monoclonal antibodies to virulent gonococci recognized an antigenic site of the lipopolysaccharide (LPS) produced in large amounts by gonococci grown in vivo but present only in a small proportion of in vitro-grown gonococci. This antigen (C-LPS) was found in all 85 different gonococcal isolates studied but not among nonpathogenic neisseriae. It was shared by group B and C meningococci but not by groups A and D. Enzyme-linked immunosorbent assay and Western blot analysis showed that N-acetylglucosamine and N-acetylgalactosamine form part of the epitope. The C-LPS antigen was shown by immunofluorescence to be present on the surface of the gonococci and also free as slime. This antigen appears to confer resistance to killing by normal sera.

  10. 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.

  11. 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

  12. 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.

  13. Rabies virus glycoprotein as a carrier for anthrax protective antigen

    International Nuclear Information System (INIS)

    Smith, Mary Ellen; Koser, Martin; Xiao Sa; Siler, Catherine; McGettigan, James P.; Calkins, Catherine; Pomerantz, Roger J.; Dietzschold, Bernhard; Schnell, Matthias J.

    2006-01-01

    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

  14. 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 ...

  15. Glycosylation of the major human Pneumocystis carinii surface antigen

    DEFF Research Database (Denmark)

    Lundgren, Bettina; Koch, C; Mathiesen, Lars Reinhardt

    1993-01-01

    -mannose and bisected complex-type glycans. Using a polyclonal antibody raised against purified gp95 and crossed affinoimmunoelectrophoresis and the lectins Con A and WGA, gp95 exhibited carbohydrate-dependent microheterogeneity. We therefore suggest that gp95 is composed of subtypes which differ in N...

  16. 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 ...

  17. 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.

  18. 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 ...

  19. Sero-prevalence of hepatitis B surface antigen among primary ...

    African Journals Online (AJOL)

    of 2-7% in Southern and Eastern Europe to low rates of less than 2%, in .... Table 2. Distribution of HBsAg by Age and Gender amongst Primary School Pupils in the Hawal valley ... effective manner and the global assessment of hepatitis B. 13 ... settlement in the Middle Hawal Valley, Nigeria, Trans Roy. Soc Trop Med Hyg ...

  20. 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 ...

  1. Prevalence of hepatitis B surface antigen sero-positivity and

    African Journals Online (AJOL)

    2016-07-31

    Jul 31, 2016 ... health burden. ... Five hundred and thirty consecutively recruited voluntary blood ... The prevalence of hepatitis infection among the blood donors was 51 (9.6%). ... of countries endemic for HBV infection with a current ... undermining the blood safety in Sub-Sahara Africa .... found in the work of Bhatti et al.

  2. Subdominant Outer Membrane Antigens in Anaplasma marginale: Conservation, Antigenicity, and Protective Capacity Using Recombinant Protein.

    Directory of Open Access Journals (Sweden)

    Deirdre R Ducken

    Full Text Available Anaplasma marginale is a tick-borne rickettsial pathogen of cattle with a worldwide distribution. Currently a safe and efficacious vaccine is unavailable. Outer membrane protein (OMP extracts or a defined surface protein complex reproducibly induce protective immunity. However, there are several knowledge gaps limiting progress in vaccine development. First, are these OMPs conserved among the diversity of A. marginale strains circulating in endemic regions? Second, are the most highly conserved outer membrane proteins in the immunogens recognized by immunized and protected animals? Lastly, can this subset of OMPs recognized by antibody from protected vaccinates and conserved among strains recapitulate the protection of outer membrane vaccines? To address the first goal, genes encoding OMPs AM202, AM368, AM854, AM936, AM1041, and AM1096, major subdominant components of the outer membrane, were cloned and sequenced from geographically diverse strains and isolates. AM202, AM936, AM854, and AM1096 share 99.9 to 100% amino acid identity. AM1041 has 97.1 to 100% and AM368 has 98.3 to 99.9% amino acid identity. While all four of the most highly conserved OMPs were recognized by IgG from animals immunized with outer membranes, linked surface protein complexes, or unlinked surface protein complexes and shown to be protected from challenge, the highest titers and consistent recognition among vaccinates were to AM854 and AM936. Consequently, animals were immunized with recombinant AM854 and AM936 and challenged. Recombinant vaccinates and purified outer membrane vaccinates had similar IgG and IgG2 responses to both proteins. However, the recombinant vaccinates developed higher bacteremia after challenge as compared to adjuvant-only controls and outer membrane vaccinates. These results provide the first evidence that vaccination with specific antigens may exacerbate disease. Progressing from the protective capacity of outer membrane formulations to

  3. 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.

  4. Tumor Associated Antigenic Peptides in Prostate Cancer

    National Research Council Canada - National Science Library

    Tiwari, Raj

    1999-01-01

    .... We proposed to identify these novel antigens in an experimental rat model using purified preparations of the heat shock protein gp96 and a library of synthetic distinct antibodies that were available...

  5. Prostate-Specific Antigen (PSA) Test

    Science.gov (United States)

    ... Cancer Prostate Cancer Screening Research Prostate-Specific Antigen (PSA) Test On This Page What is the PSA ... parts of the body before being detected. The PSA test may give false-positive or false-negative ...

  6. 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

  7. 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.

  8. Immunoradiometric assay for quantification of serum antibodies to dental plaque antigen in immunized dogs

    International Nuclear Information System (INIS)

    Ahlstedt, S.; Rylander, H.

    1975-01-01

    An immunoradiometric assay (IRMA) was used for quantifying dog serum antibodies to antigens from dental plaque collected from full-grown dogs. The antigens were adsorbed onto the inner surface of plastic tubes and then incubated with dog-anti-plaque serum, 125 I-labelled anti-dog plasma-immunoglobulin was used for quantification of the specific antibodies. Four 10 months old Beagle dogs in excellent gingival health were immunized for 10 weeks with ultrasonicated dog dental plaque. The antibody levels in antisera sampled 6, 8, 10 and 11 weeks after the first antigen injection were 2 to 5 times as high as those recorded before the immunizing period. The variability of the assay as judged from the difference between duplicate samples was found to be 18 percent+-4 (p<0.01) of the mean value and the variability between the same serum ran on different test occasions 13 percent+-7 (p<0.01). The specificity of the antigen-antibody reaction in the immuno assay was tested by inhibition experiments. Preincubation of the antisera with dental plaque antigen significantly inhibited the antigen-antibody reaction in the IRMA, while bovine serum albumin did not. (author)

  9. Immunoradiometric assay for quantification of serum antibodies to dental plaque antigen in immunized dogs

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstedt, S; Rylander, H [Goeteborg Univ. (Sweden)

    1975-01-01

    An immunoradiometric assay (IRMA) was used for quantifying dog serum antibodies to antigens from dental plaque collected from full-grown dogs. The antigens were adsorbed onto the inner surface of plastic tubes and then incubated with dog-anti-plaque serum, /sup 125/I-labelled anti-dog plasma-immunoglobulin was used for quantification of the specific antibodies. Four 10 months old Beagle dogs in excellent gingival health were immunized for 10 weeks with ultrasonicated dog dental plaque. The antibody levels in antisera sampled 6, 8, 10 and 11 weeks after the first antigen injection were 2 to 5 times as high as those recorded before the immunizing period. The variability of the assay as judged from the difference between duplicate samples was found to be 18 percent+-4 (p<0.01) of the mean value and the variability between the same serum ran on different test occasions 13 percent+-7 (p<0.01). The specificity of the antigen-antibody reaction in the immuno assay was tested by inhibition experiments. Preincubation of the antisera with dental plaque antigen significantly inhibited the antigen-antibody reaction in the IRMA, while bovine serum albumin did not.

  10. 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

  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. 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

  13. 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 .

  14. Cytotoxic T lymphocyte recognition of HLA-A/B antigens introduced into EL4 cells by cell-liposome fusion.

    Science.gov (United States)

    Engelhard, V H; Powers, G A; Moore, L C; Holterman, M J; Correa-Freire, M C

    1984-01-01

    HLA-A2 and -B7 antigens were introduced into EL4 (H-2b) cells by cell-liposome fusion and were used as targets or stimulators for cytotoxic T lymphocytes (CTL) generated in C57B1/6 (H-2b) mice. It was found that such EL4-HLA cells were not recognized by CTL that had been raised against either a human cell line bearing these HLA antigens or the purified HLA-A2 and -B7 antigens reconstituted into liposomes. In addition, EL4-HLA cells were not capable of inducing CTL that could recognize a human cell line bearing HLA-A2 and -B7 antigens. Instead, EL4-HLA cells induced CTL that specifically lysed EL4-HLA cells and not human cells expressing HLA-A2 and -B7. CTL recognition required the presence of HLA antigens on the EL4 cell surface and was inhibited by antibodies against either H-2b or HLA-A/B. Monoclonal antibody binding studies showed that the expected polymorphic determinants of the HLA-A2 and -B7 antigens were still present on EL4-HLA cells. However, the specificity of CTL or their precursors that are capable of recognizing HLA-A2 or -B7 was altered after these antigens became associated with the EL4 surface. Possible explanations for these results are discussed.

  15. 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

    2013-10-01

    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 posttranslational 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.

  16. 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...

  17. Antigen Cross-Presentation of Immune Complexes

    Science.gov (United States)

    Platzer, Barbara; Stout, Madeleine; Fiebiger, Edda

    2014-01-01

    The ability of dendritic cells (DCs) to cross-present tumor antigens has long been a focus of interest to physicians, as well as basic scientists, that aim to establish efficient cell-based cancer immune therapy. A prerequisite for exploiting this pathway for therapeutic purposes is a better understanding of the mechanisms that underlie the induction of tumor-specific cytotoxic T-lymphocyte (CTL) responses when initiated by DCs via cross-presentation. The ability of humans DC to perform cross-presentation is of utmost interest, as this cell type is a main target for cell-based immunotherapy in humans. The outcome of a cross-presentation event is guided by the nature of the antigen, the form of antigen uptake, and the subpopulation of DCs that performs presentation. Generally, CD8α+ DCs are considered to be the most potent cross-presenting DCs. This paradigm, however, only applies to soluble antigens. During adaptive immune responses, immune complexes form when antibodies interact with their specific epitopes on soluble antigens. Immunoglobulin G (IgG) immune complexes target Fc-gamma receptors on DCs to shuttle exogenous antigens efficiently into the cross-presentation pathway. This receptor-mediated cross-presentation pathway is a well-described route for the induction of strong CD8+ T cell responses. IgG-mediated cross-presentation is intriguing because it permits the CD8− DCs, which are commonly considered to be weak cross-presenters, to efficiently cross-present. Engaging multiple DC subtypes for cross-presentation might be a superior strategy to boost CTL responses in vivo. We here summarize our current understanding of how DCs use IgG-complexed antigens for the efficient induction of CTL responses. Because of its importance for human cell therapy, we also review the recent advances in the characterization of cross-presentation properties of human DC subsets. PMID:24744762

  18. Expression of Tac antigen component of bovine interleukin-2 receptor in different leukocyte populations infected with Theileria parva or Theileria annulata.

    Science.gov (United States)

    Dobbelaere, D A; Prospero, T D; Roditi, I J; Kelke, C; Baumann, I; Eichhorn, M; Williams, R O; Ahmed, J S; Baldwin, C L; Clevers, H

    1990-01-01

    The Tac antigen component of the bovine interleukin-2 receptor was expressed as a Cro-beta-galactosidase fusion protein in Escherichia coli and used to raise antibodies in rabbits. These antibodies were used for flow cytofluorimetric analysis to investigate the expression of Tac antigen in a variety of Theileria parva-infected cell lines and also in three Theileria annulata-infected cell lines. Cells expressing Tac antigen on their surface were found in all T. parva-infected cell lines tested whether these were of T- or B-cell origin. T cells expressing Tac antigen could be CD4- CD8-, CD4+ CD8-, CD4- CD8+, or CD4+ CD8+. Tac antigen expression was observed both in cultures which had been maintained in the laboratory for several years and in transformed cell lines which had recently been established by infection of lymphocytes in vitro with T. parva. Northern (RNA) blot analysis demonstrated Tac antigen transcripts in RNA isolated from all T. parva-infected cell lines. Three T. annulata-infected cell lines which were not of T-cell origin were also tested. Two of them expressed Tac antigen on their surface. Abundant Tac antigen mRNA was detected in these T. annulata-infected cell lines, but only trace amounts were demonstrated in the third cell line, which contained very few Tac antigen-expressing cells. In all cell lines tested, whether cloned or uncloned, a proportion of the cells did not express detectable levels of Tac antigen on their surface. This was also the case for a number of other leukocyte surface markers. In addition, we showed that the interleukin-2 receptors were biologically functional, because addition of recombinant interleukin-2 to cultures stimulated cell proliferation. Recombinant interleukin-2 treatment also resulted in increased amounts of steady-state Tac antigen mRNA. The relevance of interleukin-2 receptor expression on Theileria-infected cells is discussed. Images PMID:1979317

  19. Novel adenovirus encoded virus-like particles displaying the placental malaria associated VAR2CSA antigen

    DEFF Research Database (Denmark)

    Andersson, Anne-Marie C; dos Santos Marques Resende, Mafalda; Salanti, Ali

    2017-01-01

    The malaria parasite Plasmodium falciparum presents antigens on the infected erythrocyte surface that bind human receptors expressed on the vascular endothelium. The VAR2CSA mediated binding to a distinct chondroitin sulphate A (CSA) is a crucial step in the pathophysiology of placental malaria a...

  20. Homology building as a means to define antigenic epitopes on dihydrofolate reductase (DHFR) from Plasmodium falciparum

    DEFF Research Database (Denmark)

    Alifrangis, Michael; Christensen, Inge T; Jørgensen, Flemming S

    2004-01-01

    in the gene coding for Pf-DHFR. Furthermore, we wanted to study the potential use of homology models in general and of Pf-DHFR in particular in predicting antigenic malarial surface epitopes. METHODS: A homology model of Pf-DHFR domain was employed to define an epitope for the development of site...

  1. Interaction forces between salivary proteins and Streptococcus mutans with and without antigen I/II

    NARCIS (Netherlands)

    Xu, C.P.; Belt-Gritter, van de B.; Dijkstra, R.J.B.; Norde, W.; Mei, van der H.C.; Busscher, H.J.

    2007-01-01

    The antigen I/II family of surface proteins is expressed by oral streptococci, including Streptococcus mutans, and mediates specific binding to, among others, salivary films. The aim of this study was to investigate the interaction forces between salivary proteins and S. mutans with (LT11) and

  2. Antigenicity and immunogenicity of a novel Plasmodium vivax circumsporozoite derived synthetic vaccine construct

    DEFF Research Database (Denmark)

    Céspedes, Nora; Jiménez, Eliécer; Lopez-Perez, Mary

    2014-01-01

    BACKGROUND: The circumsporozoite (CS) protein is a major malaria sporozoite surface antigen currently being considered as vaccine candidate. Plasmodium vivax CS (PvCS) protein comprises a dimorphic central repeat fragment flanked by conserved regions that contain functional domains involved in pa...

  3. Studies on antigenic cross-reactivity of Trichuris ovis with host mucosal antigens in goat

    OpenAIRE

    Gautam Patra; Seikh Sahanawaz Alam; Sonjoy Kumar Borthakur; Hridayesh Prasad

    2015-01-01

    Objective: To ascertain whether immunodominant antigens of Trichuris ovis might share and cross react with host molecule. Methods: Two crude protein preparations from anterior and posterior parts of Trichuris ovis were characterized along with host mucosal antigen by double immunodiffusion, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotting technique. Conventional scanning electron microscopy was performed as per standard procedure. Results: Sharp...

  4. Carcinoembryonic Antigen Level in Liver Disease

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoo Ok; Kim, Ki Whang; Park, Chang Yun [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1978-09-15

    Carcinoembryonic antigen was initially known as tumor specific antigen and had a potential diagnostic value in the detection of digestive tract malignancies. However, subsequent studies showed CEA and CEA-like antigen present in benign disease, particularly in liver. We had collected sera from 58 patients who had liver scan and later were diagnosed clinically and histologically as liver disease. We estimated CEA values and correlations were made with liver function tests in liver cirrhosis cases. The results: 1) The raised plasma carcinoembryonic antigen level were found in 13 (68.4%) of 19 patients cirrhosis, 5 (27.8%) of 18 patients in hepatoma, 5 (71%) of 7 patients in chronic active hepatitis, all 3 patients in liver abscesses, 2 (66.7%) of 3 patients in liver abscesses, 2 (66.7%) of 3 patients in obstructive biliary disease and none in each one patient of traumatic liver hematoma, subphrenic abscess and clonorchiasis. 2) There is no linear correlation between carcinoembryonic antigen level and liver function tests including serum bilirubin, alkaline phosphatase, SGOT and prothrombin time in liver patients.

  5. Human Tumor Antigens Yesterday, Today, and Tomorrow.

    Science.gov (United States)

    Finn, Olivera J

    2017-05-01

    The question of whether human tumors express antigens that can be recognized by the immune system has been answered with a resounding YES. Most were identified through spontaneous antitumor humoral and cellular immune responses found in cancer patients and include peptides, glycopeptides, phosphopeptides, viral peptides, and peptides resulting from common mutations in oncogenes and tumor-suppressor genes, or common gene fusion events. Many have been extensively tested as candidates for anticancer vaccines. More recently, attention has been focused on the potentially large number of unique tumor antigens, mutated neoantigens, that are the predicted products of the numerous mutations revealed by exome sequencing of primary tumors. Only a few have been confirmed as targets of spontaneous immunity and immunosurveillance, and even fewer have been tested in preclinical and clinical settings. The field has been divided for a long time on the relative importance of shared versus mutated antigens in tumor surveillance and as candidates for vaccines. This question will eventually need to be answered in a head to head comparison in well-designed clinical trials. One advantage that shared antigens have over mutated antigens is their potential to be used in vaccines for primary cancer prevention. Cancer Immunol Res; 5(5); 347-54. ©2017 AACR . ©2017 American Association for Cancer Research.

  6. Carcinoembryonic Antigen Level in Liver Disease

    International Nuclear Information System (INIS)

    Choi, Kyoo Ok; Kim, Ki Whang; Park, Chang Yun

    1978-01-01

    Carcinoembryonic antigen was initially known as tumor specific antigen and had a potential diagnostic value in the detection of digestive tract malignancies. However, subsequent studies showed CEA and CEA-like antigen present in benign disease, particularly in liver. We had collected sera from 58 patients who had liver scan and later were diagnosed clinically and histologically as liver disease. We estimated CEA values and correlations were made with liver function tests in liver cirrhosis cases. The results: 1) The raised plasma carcinoembryonic antigen level were found in 13 (68.4%) of 19 patients cirrhosis, 5 (27.8%) of 18 patients in hepatoma, 5 (71%) of 7 patients in chronic active hepatitis, all 3 patients in liver abscesses, 2 (66.7%) of 3 patients in liver abscesses, 2 (66.7%) of 3 patients in obstructive biliary disease and none in each one patient of traumatic liver hematoma, subphrenic abscess and clonorchiasis. 2) There is no linear correlation between carcinoembryonic antigen level and liver function tests including serum bilirubin, alkaline phosphatase, SGOT and prothrombin time in liver patients.

  7. Original antigenic sin responses to influenza viruses.

    Science.gov (United States)

    Kim, Jin Hyang; Skountzou, Ioanna; Compans, Richard; Jacob, Joshy

    2009-09-01

    Most immune responses follow Burnet's rule in that Ag recruits specific lymphocytes from a large repertoire and induces them to proliferate and differentiate into effector cells. However, the phenomenon of "original antigenic sin" stands out as a paradox to Burnet's rule of B cell engagement. Humans, upon infection with a novel influenza strain, produce Abs against older viral strains at the expense of responses to novel, protective antigenic determinants. This exacerbates the severity of the current infection. This blind spot of the immune system and the redirection of responses to the "original Ag" rather than to novel epitopes were described fifty years ago. Recent reports have questioned the existence of this phenomenon. Hence, we revisited this issue to determine the extent to which original antigenic sin is induced by variant influenza viruses. Using two related strains of influenza A virus, we show that original antigenic sin leads to a significant decrease in development of protective immunity and recall responses to the second virus. In addition, we show that sequential infection of mice with two live influenza virus strains leads to almost exclusive Ab responses to the first viral strain, suggesting that original antigenic sin could be a potential strategy by which variant influenza viruses subvert the immune system.

  8. Evaluation of Antigen-Conjugated Fluorescent Beads to Identify Antigen-Specific B Cells.

    Science.gov (United States)

    Correa, Isabel; Ilieva, Kristina M; Crescioli, Silvia; Lombardi, Sara; Figini, Mariangela; Cheung, Anthony; Spicer, James F; Tutt, Andrew N J; Nestle, Frank O; Karagiannis, Panagiotis; Lacy, Katie E; Karagiannis, Sophia N

    2018-01-01

    Selection of single antigen-specific B cells to identify their expressed antibodies is of considerable interest for evaluating human immune responses. Here, we present a method to identify single antibody-expressing cells using antigen-conjugated fluorescent beads. To establish this, we selected Folate Receptor alpha (FRα) as a model antigen and a mouse B cell line, expressing both the soluble and the membrane-bound forms of a human/mouse chimeric antibody (MOv18 IgG1) specific for FRα, as test antibody-expressing cells. Beads were conjugated to FRα using streptavidin/avidin-biotin bridges and used to select single cells expressing the membrane-bound form of anti-FRα. Bead-bound cells were single cell-sorted and processed for single cell RNA retrotranscription and PCR to isolate antibody heavy and light chain variable regions. Variable regions were then cloned and expressed as human IgG1/k antibodies. Like the original clone, engineered antibodies from single cells recognized native FRα. To evaluate whether antigen-coated beads could identify specific antibody-expressing cells in mixed immune cell populations, human peripheral blood mononuclear cells (PBMCs) were spiked with test antibody-expressing cells. Antigen-specific cells could comprise up to 75% of cells selected with antigen-conjugated beads when the frequency of the antigen-positive cells was 1:100 or higher. In PBMC pools, beads conjugated to recombinant antigens FRα and HER2 bound antigen-specific anti-FRα MOv18 and anti-HER2 Trastuzumab antibody-expressing cells, respectively. From melanoma patient-derived B cells selected with melanoma cell line-derived protein-coated fluorescent beads, we generated a monoclonal antibody that recognized melanoma antigen-coated beads. This approach may be further developed to facilitate analysis of B cells and their antibody profiles at the single cell level and to help unravel humoral immune repertoires.

  9. Evaluation of Antigen-Conjugated Fluorescent Beads to Identify Antigen-Specific B Cells

    Directory of Open Access Journals (Sweden)

    Isabel Correa

    2018-03-01

    Full Text Available Selection of single antigen-specific B cells to identify their expressed antibodies is of considerable interest for evaluating human immune responses. Here, we present a method to identify single antibody-expressing cells using antigen-conjugated fluorescent beads. To establish this, we selected Folate Receptor alpha (FRα as a model antigen and a mouse B cell line, expressing both the soluble and the membrane-bound forms of a human/mouse chimeric antibody (MOv18 IgG1 specific for FRα, as test antibody-expressing cells. Beads were conjugated to FRα using streptavidin/avidin-biotin bridges and used to select single cells expressing the membrane-bound form of anti-FRα. Bead-bound cells were single cell-sorted and processed for single cell RNA retrotranscription and PCR to isolate antibody heavy and light chain variable regions. Variable regions were then cloned and expressed as human IgG1/k antibodies. Like the original clone, engineered antibodies from single cells recognized native FRα. To evaluate whether antigen-coated beads could identify specific antibody-expressing cells in mixed immune cell populations, human peripheral blood mononuclear cells (PBMCs were spiked with test antibody-expressing cells. Antigen-specific cells could comprise up to 75% of cells selected with antigen-conjugated beads when the frequency of the antigen-positive cells was 1:100 or higher. In PBMC pools, beads conjugated to recombinant antigens FRα and HER2 bound antigen-specific anti-FRα MOv18 and anti-HER2 Trastuzumab antibody-expressing cells, respectively. From melanoma patient-derived B cells selected with melanoma cell line-derived protein-coated fluorescent beads, we generated a monoclonal antibody that recognized melanoma antigen-coated beads. This approach may be further developed to facilitate analysis of B cells and their antibody profiles at the single cell level and to help unravel humoral immune repertoires.

  10. Evaluation of Antigen-Conjugated Fluorescent Beads to Identify Antigen-Specific B Cells

    Science.gov (United States)

    Correa, Isabel; Ilieva, Kristina M.; Crescioli, Silvia; Lombardi, Sara; Figini, Mariangela; Cheung, Anthony; Spicer, James F.; Tutt, Andrew N. J.; Nestle, Frank O.; Karagiannis, Panagiotis; Lacy, Katie E.; Karagiannis, Sophia N.

    2018-01-01

    Selection of single antigen-specific B cells to identify their expressed antibodies is of considerable interest for evaluating human immune responses. Here, we present a method to identify single antibody-expressing cells using antigen-conjugated fluorescent beads. To establish this, we selected Folate Receptor alpha (FRα) as a model antigen and a mouse B cell line, expressing both the soluble and the membrane-bound forms of a human/mouse chimeric antibody (MOv18 IgG1) specific for FRα, as test antibody-expressing cells. Beads were conjugated to FRα using streptavidin/avidin-biotin bridges and used to select single cells expressing the membrane-bound form of anti-FRα. Bead-bound cells were single cell-sorted and processed for single cell RNA retrotranscription and PCR to isolate antibody heavy and light chain variable regions. Variable regions were then cloned and expressed as human IgG1/k antibodies. Like the original clone, engineered antibodies from single cells recognized native FRα. To evaluate whether antigen-coated beads could identify specific antibody-expressing cells in mixed immune cell populations, human peripheral blood mononuclear cells (PBMCs) were spiked with test antibody-expressing cells. Antigen-specific cells could comprise up to 75% of cells selected with antigen-conjugated beads when the frequency of the antigen-positive cells was 1:100 or higher. In PBMC pools, beads conjugated to recombinant antigens FRα and HER2 bound antigen-specific anti-FRα MOv18 and anti-HER2 Trastuzumab antibody-expressing cells, respectively. From melanoma patient-derived B cells selected with melanoma cell line-derived protein-coated fluorescent beads, we generated a monoclonal antibody that recognized melanoma antigen-coated beads. This approach may be further developed to facilitate analysis of B cells and their antibody profiles at the single cell level and to help unravel humoral immune repertoires. PMID:29628923

  11. Dengue virus-like particles mimic the antigenic properties of the infectious dengue virus envelope.

    Science.gov (United States)

    Metz, Stefan W; Thomas, Ashlie; White, Laura; Stoops, Mark; Corten, Markus; Hannemann, Holger; de Silva, Aravinda M

    2018-04-02

    The 4 dengue serotypes (DENV) are mosquito-borne pathogens that are associated with severe hemorrhagic disease. DENV particles have a lipid bilayer envelope that anchors two membrane glycoproteins prM and E. Two E-protein monomers form head-to-tail homodimers and three E-dimers align to form "rafts" that cover the viral surface. Some human antibodies that strongly neutralize DENV bind to quaternary structure epitopes displayed on E protein dimers or higher order structures forming the infectious virus. Expression of prM and E in cell culture leads to the formation of DENV virus-like particles (VLPs) which are smaller than wildtype virus particles and replication defective due to the absence of a viral genome. There is no data available that describes the antigenic landscape on the surface of flavivirus VLPs in comparison to the better studied infectious virion. A large panel of well characterized antibodies that recognize epitope of ranging complexity were used in biochemical analytics to obtain a comparative antigenic surface view of VLPs in respect to virus particles. DENV patient serum depletions were performed the show the potential of VLPs in serological diagnostics. VLPs were confirmed to be heterogeneous in size morphology and maturation state. Yet, we show that many highly conformational and quaternary structure-dependent antibody epitopes found on virus particles are efficiently displayed on DENV1-4 VLP surfaces as well. Additionally, DENV VLPs can efficiently be used as antigens to deplete DENV patient sera from serotype specific antibody populations. This study aids in further understanding epitopic landscape of DENV VLPs and presents a comparative antigenic surface view of VLPs in respect to virus particles. We propose the use VLPs as a safe and practical alternative to infectious virus as a vaccine and diagnostic antigen.

  12. 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...

  13. Antigenic typing Polish isolates of canine parvovirus

    Energy Technology Data Exchange (ETDEWEB)

    Mizak, B. [National Veterinary Research Institute, Pulawy (Poland); Plucienniczak, A. [Polish Academy ofd Sciences. Microbiology and Virology Center, Lodz (Poland)

    1995-12-31

    Polish strains of canine parvovirus isolated between 1982 and 1993 were examined to determine the extent to which the virus has evolved antigenically and genetically over eleven years. Two CPV isolates obtained in Warsaw in 1982 and Pulawy in 1993, were examined using monoclonal antibody typing, restriction analysis and sequencing VP-2 protein gene. Five other isolates from Warsaw and Pulawy were tested with the panel of monoclonal antibodies specific to CPV-2, CPV-2a and common for canine parvovirus, feline panleukopenia virus and milk enteritis virus. Results of the studies demonstrated that all isolates tested represented CPV-2a antigenic type. Rapid antigenic strain replacement recorded by Parrish and Senda in the U.S.A and Japan was not confirmed in Poland. (author). 30 refs, 2 tabs.

  14. Harnessing Dendritic Cells for Tumor Antigen Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Nierkens, Stefan [Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein 28, Nijmegen 6525 GA (Netherlands); Janssen, Edith M., E-mail: edith.janssen@cchmc.org [Division of Molecular Immunology, Cincinnati Children' s Hospital Research Foundation, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH 45229 (United States)

    2011-04-26

    Dendritic cells (DC) are professional antigen presenting cells that are crucial for the induction of anti-tumor T cell responses. As a consequence, research has focused on the harnessing of DCs for therapeutic interventions. Although current strategies employing ex vivo-generated and tumor-antigen loaded DCs have been proven feasible, there are still many obstacles to overcome in order to improve clinical trial successes and offset the cost and complexity of customized cell therapy. This review focuses on one of these obstacles and a pivotal step for the priming of tumor-specific CD8{sup +} and CD4{sup +} T cells; the in vitro loading of DCs with tumor antigens.

  15. Antigenic typing Polish isolates of canine parvovirus

    International Nuclear Information System (INIS)

    Mizak, B.; Plucienniczak, A.

    1995-01-01

    Polish strains of canine parvovirus isolated between 1982 and 1993 were examined to determine the extent to which the virus has evolved antigenically and genetically over eleven years. Two CPV isolates obtained in Warsaw in 1982 and Pulawy in 1993, were examined using monoclonal antibody typing, restriction analysis and sequencing VP-2 protein gene. Five other isolates from Warsaw and Pulawy were tested with the panel of monoclonal antibodies specific to CPV-2, CPV-2a and common for canine parvovirus, feline panleukopenia virus and milk enteritis virus. Results of the studies demonstrated that all isolates tested represented CPV-2a antigenic type. Rapid antigenic strain replacement recorded by Parrish and Senda in the U.S.A and Japan was not confirmed in Poland. (author). 30 refs, 2 tabs

  16. Original antigenic sin: A comprehensive review.

    Science.gov (United States)

    Vatti, Anup; Monsalve, Diana M; Pacheco, Yovana; Chang, Christopher; Anaya, Juan-Manuel; Gershwin, M Eric

    2017-09-01

    The concept of "original antigenic sin" was first proposed by Thomas Francis, Jr. in 1960. This phenomenon has the potential to rewrite what we understand about how the immune system responds to infections and its mechanistic implications on how vaccines should be designed. Antigenic sin has been demonstrated to occur in several infectious diseases in both animals and humans, including human influenza infection and dengue fever. The basis of "original antigenic sin" requires immunological memory, and our immune system ability to autocorrect. In the context of viral infections, it is expected that if we are exposed to a native strain of a pathogen, we should be able to mount a secondary immune response on subsequent exposure to the same pathogen. "Original antigenic sin" will not contradict this well-established immunological process, as long as the subsequent infectious antigen is identical to the original one. But "original antigenic sin" implies that when the epitope varies slightly, then the immune system relies on memory of the earlier infection, rather than mount another primary or secondary response to the new epitope which would allow faster and stronger responses. The result is that the immunological response may be inadequate against the new strain, because the immune system does not adapt and instead relies on its memory to mount a response. In the case of vaccines, if we only immunize to a single strain or epitope, and if that strain/epitope changes over time, then the immune system is unable to mount an accurate secondary response. In addition, depending of the first viral exposure the secondary immune response can result in an antibody-dependent enhancement of the disease or at the opposite, it could induce anergy. Both of them triggering loss of pathogen control and inducing aberrant clinical consequences. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Heterologous expression of antigenic peptides in Bacillus subtilis biofilms.

    Science.gov (United States)

    Vogt, Cédric M; Schraner, Elisabeth M; Aguilar, Claudio; Eichwald, Catherine

    2016-08-11

    Numerous strategies have been developed for the display of heterologous proteins in the surface of live bacterial carriers, which can be used as vaccines, immune-modulators, cancer therapy or bioremediation. Bacterial biofilms have emerged as an interesting approach for the expression of proteins of interest. Bacillus subtilis is a well-described, endospore-forming organism that is able to form biofilms and also used as a probiotic, thus making it a suitable candidate for the display of heterologous proteins within the biofilm. Here, we describe the use of TasA, an important structural component of the biofilms formed by B. subtilis, as a genetic tool for the display of heterologous proteins. We first engineered the fusion protein TasA-mCherry and showed that was widely deployed within the B. subtilis biofilms. A significant enhancement of the expression of TasA-mCherry within the biofilm was obtained when depleting both tasA and sinR genes. We subsequently engineered fusion proteins of TasA to antigenic peptides of the E. granulosus parasite, paramyosin and tropomyosin. Our results show that the antigens were well expressed within the biofilm as denoted by macrostructure complementation and by the detection of the fusion protein in both immunoblot and immunohistochemistry. In addition, we show that the recombinant endospores of B. subtilis preserve their biophysical and morphological properties. In this work we provide strong evidence pointing that TasA is a suitable candidate for the display of heterologous peptides, such as antigens, cytokines, enzymes or antibodies, in the B. subtilis biofilms. Finally, our data portray that the recombinant endospores preserve their morphological and biophysical properties and could be an excellent tool to facilitate the transport and the administration.

  18. Differing patterns of selection and geospatial genetic diversity within two leading Plasmodium vivax candidate vaccine antigens.

    Directory of Open Access Journals (Sweden)

    Christian M Parobek

    2014-04-01

    Full Text Available Although Plasmodium vivax is a leading cause of malaria around the world, only a handful of vivax antigens are being studied for vaccine development. Here, we investigated genetic signatures of selection and geospatial genetic diversity of two leading vivax vaccine antigens--Plasmodium vivax merozoite surface protein 1 (pvmsp-1 and Plasmodium vivax circumsporozoite protein (pvcsp. Using scalable next-generation sequencing, we deep-sequenced amplicons of the 42 kDa region of pvmsp-1 (n = 44 and the complete gene of pvcsp (n = 47 from Cambodian isolates. These sequences were then compared with global parasite populations obtained from GenBank. Using a combination of statistical and phylogenetic methods to assess for selection and population structure, we found strong evidence of balancing selection in the 42 kDa region of pvmsp-1, which varied significantly over the length of the gene, consistent with immune-mediated selection. In pvcsp, the highly variable central repeat region also showed patterns consistent with immune selection, which were lacking outside the repeat. The patterns of selection seen in both genes differed from their P. falciparum orthologs. In addition, we found that, similar to merozoite antigens from P. falciparum malaria, genetic diversity of pvmsp-1 sequences showed no geographic clustering, while the non-merozoite antigen, pvcsp, showed strong geographic clustering. These findings suggest that while immune selection may act on both vivax vaccine candidate antigens, the geographic distribution of genetic variability differs greatly between these two genes. The selective forces driving this diversification could lead to antigen escape and vaccine failure. Better understanding the geographic distribution of genetic variability in vaccine candidate antigens will be key to designing and implementing efficacious vaccines.

  19. Photochemical Internalization of Peptide Antigens Provides a Novel Strategy to Realize Therapeutic Cancer Vaccination

    Directory of Open Access Journals (Sweden)

    Markus Haug

    2018-04-01

    Full Text Available Effective priming and activation of tumor-specific CD8+ cytotoxic T lymphocytes (CTLs is crucial for realizing the potential of therapeutic cancer vaccination. This requires cytosolic antigens that feed into the MHC class I presentation pathway, which is not efficiently achieved with most current vaccination technologies. Photochemical internalization (PCI provides an emerging technology to route endocytosed material to the cytosol of cells, based on light-induced disruption of endosomal membranes using a photosensitizing compound. Here, we investigated the potential of PCI as a novel, minimally invasive, and well-tolerated vaccination technology to induce priming of cancer-specific CTL responses to peptide antigens. We show that PCI effectively promotes delivery of peptide antigens to the cytosol of antigen-presenting cells (APCs in vitro. This resulted in a 30-fold increase in MHC class I/peptide complex formation and surface presentation, and a subsequent 30- to 100-fold more efficient activation of antigen-specific CTLs compared to using the peptide alone. The effect was found to be highly dependent on the dose of the PCI treatment, where optimal doses promoted maturation of immature dendritic cells, thus also providing an adjuvant effect. The effect of PCI was confirmed in vivo by the successful induction of antigen-specific CTL responses to cancer antigens in C57BL/6 mice following intradermal peptide vaccination using PCI technology. We thus show new and strong evidence that PCI technology holds great potential as a novel strategy for improving the outcome of peptide vaccines aimed at triggering cancer-specific CD8+ CTL responses.

  20. Identification of antigenic proteins of setaria cervi by immunoblotting technique

    International Nuclear Information System (INIS)

    Kaushal, N.A.; Kaushal, D.C.; Ghatak, S.

    1987-01-01

    Identification and characterization of antigenic proteins of Setaria cervi (bovine filarial parasite) adults and microfilariae was done by immunoblotting technique using hyperimmune rabbit sera against S. cervi and Brugia malayi. The antigens recognized by these sera were detected by using 125 I protein-A followed by autoradiography. Fifteen different antigens were observed to be common between adult and microfilarial stages of the parasite. Some stage specific antigens were also identified. Many antigens of S. cervi adults and microfilariae were also recognized by rabbit anti-B.malayi serum showing the existence of common antigenic determinants between the bovine and human filarial parasites

  1. The physical stability of the recombinant tuberculosis fusion antigens h1 and h56

    DEFF Research Database (Denmark)

    Hamborg, Mette; Kramer, Ryan; Schanté, Carole E

    2013-01-01

    a gradual loss of secondary as well as tertiary structure as a function of temperature, with no cooperative transitions observed. Preformulation studies with the Th1-inducing cationic adjuvant CAF01 showed that the antigens were almost completely surface adsorbed. Upon adsorption, the liposome size...... and it is therefore important to characterize their conformational stability in solution as well as upon interaction with adjuvants. In this study, the physical stability of the two antigens was characterized using a number of biophysical techniques. Dynamic light scattering and sodium dodecyl sulfate...... increased; however, the physical stabilities of the bound and the unbound antigens were comparable. This study provides important information about the biophysical properties of H1 and H56 and highlights the analytical challenges of characterizing complex vaccine formulations....

  2. Biosynthetic incorporation of [75Se]selenomethionine: a new method for labelling lymphocyte membrane antigens

    International Nuclear Information System (INIS)

    Dosseto, M.; Rohner, C.; Pierres, M.; Goridis, C.

    1981-01-01

    A novel approach for radiolabelling lymphocyte membrane antigens is described. This technique is based on the use of the γ-emitting amino acid analogue [ 75 Se]selenomethionine. Human HLA-A, B, C and DR heavy and light chains and mouse Ia antigens were efficiently labelled by this technique and were precipitated with monoclonal antibodies. Approximately the same radioactivity was incorporated into the HLA-A, B, C chains whether [ 75 Se]selenomethionine, [ 35 S]methionine or [ 3 H]leucine were used as precursors. Easily detectable as a γ-emitter, [ 75 Se]selenomethionine thus constitutes a useful biosynthetic label of lymphocyte surface antigens. The same method was used to label immunoglobulins produced by hybridomas and to determine the nature of the secreted light chains. (Auth.)

  3. Effect of radiation on the expression of carcinoembryonic antigen of human gastric adenocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Hareyama, M.; Imai, K.; Kubo, K.; Takahashi, H.; Koshiba, H.; Hinoda, Y.; Shidou, M.; Oouchi, A.; Yachi, A.; Morita, K. (Sapporo Medical College (Japan))

    1991-05-01

    The changes of antigenic expression of cultured human gastric adenocarcinoma MKN45 cells caused by irradiation were investigated to elucidate the immune responses to localized irradiation. The expression of carcinoembryonic antigen (CEA) showed remarkable increases in the culture supernatant and on the surface of the membrane of irradiated cells. The expression of major histocompatibility complex Class I antigen on the membrane also was enhanced by irradiation. In addition, the irradiated cell groups, when analyzed using a CEA-specific probe, showed remarkable increases in the CEA mRNA. These enhancements increased in the 10-Gy and 15-Gy irradiated populations compared with the 5-Gy irradiated population. These results suggest that the enhancement of expression of CEA by radiation takes place at the CEA gene expression (mRNA) level but not at the protein level.

  4. Genetic diversity of K-antigen gene clusters of Escherichia coli and their molecular typing using a suspension array.

    Science.gov (United States)

    Yang, Shuang; Xi, Daoyi; Jing, Fuyi; Kong, Deju; Wu, Junli; Feng, Lu; Cao, Boyang; Wang, Lei

    2018-04-01

    Capsular polysaccharides (CPSs), or K-antigens, are the major surface antigens of Escherichia coli. More than 80 serologically unique K-antigens are classified into 4 groups (Groups 1-4) of capsules. Groups 1 and 4 contain the Wzy-dependent polymerization pathway and the gene clusters are in the order galF to gnd; Groups 2 and 3 contain the ABC-transporter-dependent pathway and the gene clusters consist of 3 regions, regions 1, 2 and 3. Little is known about the variations among the gene clusters. In this study, 9 serotypes of K-antigen gene clusters (K2ab, K11, K20, K24, K38, K84, K92, K96, and K102) were sequenced and correlated with their CPS chemical structures. On the basis of sequence data, a K-antigen-specific suspension array that detects 10 distinct CPSs, including the above 9 CPSs plus K30, was developed. This is the first report to catalog the genetic features of E. coli K-antigen variations and to develop a suspension array for their molecular typing. The method has a number of advantages over traditional bacteriophage and serum agglutination methods and lays the foundation for straightforward identification and detection of additional K-antigens in the future.

  5. Crystal structure of the anti-(carcinoembryonic antigen) single-chain Fv antibody MFE-23 and a model for antigen binding based on intermolecular contacts.

    Science.gov (United States)

    Boehm, M K; Corper, A L; Wan, T; Sohi, M K; Sutton, B J; Thornton, J D; Keep, P A; Chester, K A; Begent, R H; Perkins, S J

    2000-03-01

    MFE-23 is the first single-chain Fv antibody molecule to be used in patients and is used to target colorectal cancer through its high affinity for carcinoembryonic antigen (CEA), a cell-surface member of the immunoglobulin superfamily. MFE-23 contains an N-terminal variable heavy-chain domain joined by a (Gly(4)Ser)(3) linker to a variable light-chain (V(L)) domain (kappa chain) with an 11-residue C-terminal Myc-tag. Its crystal structure was determined at 2.4 A resolution by molecular replacement with an R(cryst) of 19.0%. Five of the six antigen-binding loops, L1, L2, L3, H1 and H2, conformed to known canonical structures. The sixth loop, H3, displayed a unique structure, with a beta-hairpin loop and a bifurcated apex characterized by a buried Thr residue. In the crystal lattice, two MFE-23 molecules were associated back-to-back in a manner not seen before. The antigen-binding site displayed a large acidic region located mainly within the H2 loop and a large hydrophobic region within the H3 loop. Even though this structure is unliganded within the crystal, there is an unusually large region of contact between the H1, H2 and H3 loops and the beta-sheet of the V(L) domain of an adjacent molecule (strands DEBA) as a result of intermolecular packing. These interactions exhibited remarkably high surface and electrostatic complementarity. Of seven MFE-23 residues predicted to make contact with antigen, five participated in these lattice contacts, and this model for antigen binding is consistent with previously reported site-specific mutagenesis of MFE-23 and its effect on CEA binding.

  6. Evidence that a glycolipid tail anchors antigen 117 to the plasma membrane of Dictyostelium discoideum cells

    International Nuclear Information System (INIS)

    Sadeghi, H.; Da Silva, A.M.; Klein, C.

    1988-01-01

    The authors describe the biochemical features of the putative cell cohesion molecule antigen 117, indicating that it is anchored to the plasma membrane by a glycolipid tail. Antigen 117 can be radiolabeled with [ 3 H]myristate, [ 3 H]palmitate, and [ 14 C]ethanolamine. The fatty acid label is removed by periodate oxidation and nitrous acid deamination, indicating that the fatty acid is attached to the protein by a structure containing carbohydrate and an unsubstituted glucosamine. As cells develop aggregation competence, the antigen is released from the cell surface in a soluble form that can still be radiolabeled with [ 14 C]ethanolamine but not with [ 3 H]myristate of [ 3 H]-palmitate. The molecular weight of the released antigen is similar to that found in the plasma membrane, but it preferentially partitions in Triton X-114 as a hydrophilic, as opposed to a hydrophobic, protein. Plasma membranes contain the enzyme activity responsible for the release of the antigen in a soluble form

  7. Immunoregulatory adherent cells in human tuberculosis: radiation-sensitive antigen-specific suppression by monocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kleinhenz, M.E.; Ellner, J.J.

    1985-07-01

    In human tuberculosis, adherent mononuclear cells (AMC) selectively depress in vitro responses to the mycobacterial antigen tuberculin purified protein derivative (PPD). The phenotype of this antigen-specific adherent suppressor cell was characterized by examining the functional activity of adherent cells after selective depletion of sheep erythrocyte-rosetting T cells or OKM1-reactive monocytes. Adherent cell suppression was studied in the (/sup 3/H)thymidine-incorporation microculture assay by using T cells rigorously depleted of T cells with surface receptors for the Fc portion of IgG (T gamma cells) as antigen-responsive cells. PPD-induced (/sup 3/H)thymidine incorporation by these non gamma T cells was uniformly reduced (mean, 42% +/- 10% (SD)) when autologous AMC were added to non gamma T cells at a ratio of 1:2. Antigen-specific suppression by AMC was not altered by depletion of sheep erythrocyte-rosetting T cells or treatment with indomethacin. However, AMC treated with OKM1 and complement or gamma irradiation (1,500 rads) no longer suppressed tuberculin responses in vitro. These studies identify the antigen-specific adherent suppressor cell in tuberculosis as an OKM1-reactive, non-erythrocyte-rosetting monocyte. The radiosensitivity of this monocyte immunoregulatory function may facilitate its further definition.

  8. Immunoregulatory adherent cells in human tuberculosis: radiation-sensitive antigen-specific suppression by monocytes

    International Nuclear Information System (INIS)

    Kleinhenz, M.E.; Ellner, J.J.

    1985-01-01

    In human tuberculosis, adherent mononuclear cells (AMC) selectively depress in vitro responses to the mycobacterial antigen tuberculin purified protein derivative (PPD). The phenotype of this antigen-specific adherent suppressor cell was characterized by examining the functional activity of adherent cells after selective depletion of sheep erythrocyte-rosetting T cells or OKM1-reactive monocytes. Adherent cell suppression was studied in the [ 3 H]thymidine-incorporation microculture assay by using T cells rigorously depleted of T cells with surface receptors for the Fc portion of IgG (T gamma cells) as antigen-responsive cells. PPD-induced [ 3 H]thymidine incorporation by these non gamma T cells was uniformly reduced (mean, 42% +/- 10% [SD]) when autologous AMC were added to non gamma T cells at a ratio of 1:2. Antigen-specific suppression by AMC was not altered by depletion of sheep erythrocyte-rosetting T cells or treatment with indomethacin. However, AMC treated with OKM1 and complement or gamma irradiation (1,500 rads) no longer suppressed tuberculin responses in vitro. These studies identify the antigen-specific adherent suppressor cell in tuberculosis as an OKM1-reactive, non-erythrocyte-rosetting monocyte. The radiosensitivity of this monocyte immunoregulatory function may facilitate its further definition

  9. Analysis of antigen-specific B-cell memory directly ex vivo.

    Science.gov (United States)

    McHeyzer-Williams, Louise J; McHeyzer-Williams, Michael G

    2004-01-01

    Helper T-cell-regulated B-cell memory develops in response to initial antigen priming as a cellular product of the germinal center (GC) reaction. On antigen recall, memory response precursors expand rapidly with exaggerated differentiation into plasma cells to produce the high-titer, high-affinity antibody(Ab) that typifies the memory B-cell response in vivo. We have devised a high-resolution flow cytometric strategy to quantify the emergence and maintenance of antigen-specific memory B cells directly ex vivo. Extended cell surface phenotype establishes a level of cellular diversity not previously appreciated for the memory B-cell compartment. Using an "exclusion transfer" strategy, we ascertain the capacity of two distinct memory B-cell populations to transfer antigen-specific memory into naive adoptive hosts. Finally, we sequence expressed messenger ribonucleic acid (mRNA) from single cells within the population to estimate the level of somatic hypermutation as the best molecular indicator of B-cell memory. In this chapter, we describe the methods used in each of these four sections that serve to provide high-resolution quantification of antigen-specific B-cell memory responses directly ex vivo.

  10. Rapid production of antigen-specific monoclonal antibodies from a variety of animals

    Directory of Open Access Journals (Sweden)

    Kurosawa Nobuyuki

    2012-09-01

    Full Text Available Abstract Background Although a variety of animals have been used to produce polyclonal antibodies against antigens, the production of antigen-specific monoclonal antibodies from animals remains challenging. Results We propose a simple and rapid strategy to produce monoclonal antibodies from a variety of animals. By staining lymph node cells with an antibody against immunoglobulin and a fluorescent dye specific for the endoplasmic reticulum, plasma/plasmablast cells were identified without using a series of antibodies against lineage markers. By using a fluorescently labeled antigen as a tag for a complementary cell surface immunoglobulin, antigen-specific plasma/plasmablast cells were sorted from the rest of the cell population by fluorescence-activated cell sorting. Amplification of cognate pairs of immunoglobulin heavy and light chain genes followed by DNA transfection into 293FT cells resulted in the highly efficient production of antigen-specific monoclonal antibodies from a variety of immunized animals. Conclusions Our technology eliminates the need for both cell propagation and screening processes, offering a significant advantage over hybridoma and display strategies.

  11. Transmission of hepatitis-B virus through salivary blood group antigens in saliva

    International Nuclear Information System (INIS)

    Meo, S.A.; Abdo, A.A.; Baksh, N.D.; Sanie, F.M.

    2010-01-01

    To determine an association between transmission of hepatitis B virus and secretor and non-secretor status of salivary blood group antigens. Study Design: Cross-sectional, analytical study. Place and Duration of Study: The Department of Physiology and Division of Hepatology, College of Medicine, King Khalid University Hospital, King Saud University, Riyadh, Kingdom of Saudi Arabia, from 2007 to 2009. Methodology: Eighty eight known patients, who were positive for Hepatitis B Surface Antigen [HBsAg] were recruited. Saliva was collected for investigating the secretor and non-secretor status by using blood typing kit number Kemtec Educational Science USA. Hepatitis B Surface antigen test was performed on Enzyme Linked Immunosorbent Assay technique. Polymerase chain reaction [PCR] on saliva was also carried out in High Performance Thermal Cycler-Palm- Cycler [Corbett Life Science, Sydney, Australia] and enzymatic amplification of extracted viral DNA was performed using primers covering the promoter of the core region of HBV. Results: Out of the 88 subjects, 61 belong to blood group O, 20 to A and 7 subjects to blood group B. Fifty subjects were secretors [salivary blood group antigens positive] and 38 subjects were non-secretors [salivary blood group antigens negative]. Among core gene positive 25 (69.4%) were secretors and 11 (30.6%) were non-secretors. However, in core gene negative 25 (48.1%) were secretors and 27 (51.9%) were non-secretors. Conclusion: The result shows an association [p=0.047] between secretor and non-secretors status of the salivary blood group antigens with core gene positive and core gene negative. (author)

  12. [Radiocompetitive method of H antigen determination].

    Science.gov (United States)

    Semenova, G B; Sokolov, Ia A; Liashenko, V A

    1978-06-01

    The authors describe a radiocompetitive method of H-d-monomere determination with the sensitivity of 2 ng/ml in double antibodies modification; this method was used for comparing the immunological affinity of the affiliated H-antigens. A difference between the immunological affinity to the antibodies in a monomere, polymere and the flagellum was shown.

  13. Immune responses to red blood cell antigens

    NARCIS (Netherlands)

    Stegmann, T.C.

    2016-01-01

    The research described in this thesis is aimed towards elucidation of the mechanism of action of anti-D. Anti-D is administered prophylactivly to prevent alloimmunization against the immunogenic D-antigen to D⁻ pregnant women carrying a D⁺ fetus. The plasma of women who became immunized during

  14. Antigen dynamics of follicular dendritic cells

    NARCIS (Netherlands)

    Heesters, B.A.

    2015-01-01

    Stromal-derived follicular dendritic cells (FDCs) are a major depot for antigen that are essential for formation of germinal centers, the site where memory and effector B cells differentiate and high-affinity antibody production takes place. Historically, FDCs have been characterized as ‘accessory’

  15. Evaluation of an Antigen-Antibody

    African Journals Online (AJOL)

    GB

    replication would lead to the production of various antigens. Today with BMT history of over 30 years, infection ... Study design: The study involved both retrospective and prospective laboratory-based analysis of ..... core protein of a molecular mass 19 x 103 Da, one picogram (pg) of virus core corresponds to 1.3 x. 105 HCV ...

  16. Lea blood group antigen on human platelets

    International Nuclear Information System (INIS)

    Dunstan, R.A.; Simpson, M.B.; Rosse, W.F.

    1985-01-01

    One- and two-stage radioligand assays were used to determine if human platelets possess the Lea antigen. Goat IgG anti-Lea antibody was purified by multiple adsorptions with Le(a-b-) human red blood cells, followed by affinity chromatography with synthetic Lea substance and labeling with 125 I. Human IgG anti-Lea antibody was used either in a two stage radioassay with 125 I-labeled mouse monoclonal IgG anti-human IgG as the second antibody or, alternatively, purified by Staph protein A chromatography, labeled with 125 I, and used in a one-stage radioassay. Platelets from donors of appropriate red blood cell phenotypes were incubated with the antisera, centrifuged through phthalate esters, and assayed in a gamma scintillation counter. Dose response and saturation curve analysis demonstrate the presence of Lewis a antigen on platelets from Lea+ donors. Furthermore, platelets from an Le(a-b-) donor incubated in Le (a+b-) plasma adsorb Lea antigen in a similar manner to red blood cells. The clinical significance of these antigens in platelet transfusion remains undefined

  17. Antigenic characterisation of lyssaviruses in South Africa

    Directory of Open Access Journals (Sweden)

    Ernest Ngoepe

    2014-09-01

    Full Text Available There are at least six Lyssavirus species that have been isolated in Africa, which include classical rabies virus, Lagos bat virus, Mokola virus, Duvenhage virus, Shimoni bat virus and Ikoma lyssavirus. In this retrospective study, an analysis of the antigenic reactivity patterns of lyssaviruses in South Africa against a panel of 15 anti-nucleoprotein monoclonal antibodies was undertaken. A total of 624 brain specimens, collected between 2005 and 2009, confirmed as containing lyssavirus antigen by direct fluorescent antibody test, were subjected to antigenic differentiation. The lyssaviruses were differentiated into two species, namely rabies virus (99.5% and Mokola virus (0.5%. Furthermore, rabies virus was further delineated into two common rabies biotypes in South Africa: canid and mongoose. Initially, it was found that the canid rabies biotype had two reactivity patterns; differential staining was observed with just one monoclonal antibody. This difference was likely to have been an artefact related to sample quality, as passage in cell culture restored staining. Mongoose rabies viruses were more heterogeneous, with seven antigenic reactivity patterns detected. Although Mokola viruses were identified in this study, prevalence and reservoir host species are yet to be established. These data demonstrate the usefulness of monoclonal antibody typing panels in lyssavirus surveillance with reference to emergence of new species or spread of rabies biotypes to new geographic zones.

  18. Antigenic and genetic variability of human metapneumoviruses

    NARCIS (Netherlands)

    S. Herfst (Sander); L. Sprong; P.A. Cane; E. Forleo-Neto; A.D.M.E. Osterhaus (Albert); R.A.M. Fouchier (Ron); R.L. de Swart (Rik); B.G. van den Hoogen (Bernadette)

    2004-01-01

    textabstractHuman metapneumovirus (HMPV) is a member of the subfamily Pneumovirinae within the family Paramyxo- viridae. Other members of this subfamily, respiratory syncytial virus and avian pneumovirus, can be divided into subgroups on the basis of genetic or antigenic differences or both. For

  19. Understanding original antigenic sin in influenza with a dynamical system.

    Science.gov (United States)

    Pan, Keyao

    2011-01-01

    Original antigenic sin is the phenomenon in which prior exposure to an antigen leads to a subsequent suboptimal immune response to a related antigen. Immune memory normally allows for an improved and rapid response to antigens previously seen and is the mechanism by which vaccination works. I here develop a dynamical system model of the mechanism of original antigenic sin in influenza, clarifying and explaining the detailed spin-glass treatment of original antigenic sin. The dynamical system describes the viral load, the quantities of healthy and infected epithelial cells, the concentrations of naïve and memory antibodies, and the affinities of naïve and memory antibodies. I give explicit correspondences between the microscopic variables of the spin-glass model and those of the present dynamical system model. The dynamical system model reproduces the phenomenon of original antigenic sin and describes how a competition between different types of B cells compromises the overall effect of immune response. I illustrate the competition between the naïve and the memory antibodies as a function of the antigenic distance between the initial and subsequent antigens. The suboptimal immune response caused by original antigenic sin is observed when the host is exposed to an antigen which has intermediate antigenic distance to a second antigen previously recognized by the host's immune system.

  20. Epidemiologic and HLA Antigen Profile in Patients with Aplastic Anemia

    International Nuclear Information System (INIS)

    Taj, M.; Shamsi, T. S.; Ansari, S. H.; Farzana, T.; Nazi, A.; Nadeem, M.; Queresi, R. N.; Sheikh, K.; Kazmi, J. H.

    2014-01-01

    Objective: To analyze patients suffering from aplastic anemia (AA, peripheral pancytopenia and hypocellular bone marrow in the absence of dysplasia, infiltration and fibrosis) for documenting patient's baseline characteristics and association with various human leucocyte antigens. Study Design: An observational, cross-sectional study. Place and Duration of Study: The National Institute of Blood Disease (NIBD), Karachi, from March 2003 to August 2008. Methodology: All consecutive patients with confirmed diagnosis of AA were evaluated. Data included the baseline characteristics, complete blood counts (CBC), bone marrow biopsy findings, severity of disease, exposure to drugs or chemicals, viral serology and their HLA expression. The data was analyzed on SPSS programme and frequencies were documented. Results: Among 318 patients, there were 236 (74.21%) males and 82 (25.78%) females. Median age was 16 and 70% belonged to urban population. Drug exposure could be established in 23 (7.23%) of cases, while 4 (1.25%) were HBV surface antigen positive and 7 (2.2%) were HCV antibodies positive. In all, 73 (22.9%) had very severe AA, 195 (61.32%) had severe AA while 50 (15.7%) cases had non-severe AA. HLA B5 (52) showed high expression in 83 patients (26%) in comparison to 5.9% reported in healthy population. Conclusion: AA was found to affect young adult males living in urban areas. HLA B5 (52) showed higher expression in patients with aplastic anemia. (author)

  1. Prostate Stem Cell Antigen: A Prospective Therapeutic and Diagnostic Target

    Science.gov (United States)

    Raff, Adam B.; Gray, Andrew; Kast, W. Martin

    2009-01-01

    The development of novel clinical tools to combat cancer is an intense field of research and recent efforts have been directed at the identification of proteins that may provide diagnostic, prognostic and/or therapeutic applications due to their restricted expression. To date, a number of protein candidates have emerged as potential clinical tools in the treatment of prostate cancer. Discovered over ten year ago, prostate stem cell antigen (PSCA) is a cell surface antigen that belongs to the Ly-6/Thy-1 family of glycosylphosphatidylinositol-anchored proteins. PSCA is highly overexpressed in human prostate cancer, with limited expression in normal tissues, making it an ideal target for both diagnosis and therapy. Several studies have now clearly correlated the expression of PSCA with relevant clinical benchmarks, such as Gleason score and metastasis, while others have demonstrated the efficacy of PSCA targeting in treatment through various modalities. The purpose of this review is to present the current body of knowledge about PSCA and its potential role in the treatment of human prostate cancer. PMID:18838214

  2. Granulocytes: New Members of the Antigen-Presenting Cell Family

    Directory of Open Access Journals (Sweden)

    Ang Lin

    2017-12-01

    Full Text Available Granulocytes, the most abundant types of leukocytes, are the first line of defense against pathogen invasion. However, the plasticity and diversity of granulocytes have been increasingly revealed, especially with regard to their versatile functions in orchestrating adaptive immune responses. A substantial body of recent evidence demonstrates that granulocytes can acquire the function as antigen-presenting cells under pathological or inflammatory conditions. In addition, they can acquire surface expression of MHC class II and costimulatory molecules as well as T cell stimulatory behavior when cultured with selected cytokines. The classic view of granulocytes as terminally differentiated, short-lived phagocytes is therefore changing to phenotypically and functionally heterogeneous cells that are engaged in cross-talk with other leukocyte populations and provide an additional link between innate and adaptive immunity. In this brief review, we summarize the current knowledge on the antigen-presenting capacity of granulocyte subsets (neutrophils, eosinophils, and basophils. Underlying mechanisms, relevant physiological significance and potential controversies are also discussed.

  3. Peripheral neuropathies associated with antibodies directed to intracellular neural antigens.

    Science.gov (United States)

    Antoine, J-C

    2014-10-01

    Antibodies directed to intracellular neural antigens have been mainly described in paraneoplastic peripheral neuropathies and mostly includes anti-Hu and anti-CV2/CRMP5 antibodies. These antibodies occur with different patterns of neuropathy. With anti-Hu antibody, the most frequent manifestation is sensory neuronopathy with frequent autonomic involvement. With anti-CV2/CRMP5 the neuropathy is more frequently sensory and motor with an axonal or mixed demyelinating and axonal electrophysiological pattern. The clinical pattern of these neuropathies is in keeping with the cellular distribution of HuD and CRMP5 in the peripheral nervous system. Although present in high titer, these antibodies are probably not directly responsible for the neuropathy. Pathological and experimental studies indicate that cytotoxic T-cells are probably the main effectors of the immune response. These disorders contrast with those in which antibodies recognize a cell surface antigen and are probably responsible for the disease. The neuronal cell death and axonal degeneration which result from T-cell mediated immunity explains why treating these disorders remains challenging. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  4. Increasing vaccine potency through exosome antigen targeting.

    Science.gov (United States)

    Hartman, Zachary C; Wei, Junping; Glass, Oliver K; Guo, Hongtao; Lei, Gangjun; Yang, Xiao-Yi; Osada, Takuya; Hobeika, Amy; Delcayre, Alain; Le Pecq, Jean-Bernard; Morse, Michael A; Clay, Timothy M; Lyerly, Herbert K

    2011-11-21

    While many tumor associated antigens (TAAs) have been identified in human cancers, efforts to develop efficient TAA "cancer vaccines" using classical vaccine approaches have been largely ineffective. Recently, a process to specifically target proteins to exosomes has been established which takes advantage of the ability of the factor V like C1C2 domain of lactadherin to specifically address proteins to exosomes. Using this approach, we hypothesized that TAAs could be targeted to exosomes to potentially increase their immunogenicity, as exosomes have been demonstrated to traffic to antigen presenting cells (APC). To investigate this possibility, we created adenoviral vectors expressing the extracellular domain (ECD) of two non-mutated TAAs often found in tumors of cancer patients, carcinoembryonic antigen (CEA) and HER2, and coupled them to the C1C2 domain of lactadherin. We found that these C1C2 fusion proteins had enhanced expression in exosomes in vitro. We saw significant improvement in antigen specific immune responses to each of these antigens in naïve and tolerant transgenic animal models and could further demonstrate significantly enhanced therapeutic anti-tumor effects in a human HER2+ transgenic animal model. These findings demonstrate that the mode of secretion and trafficking can influence the immunogenicity of different human TAAs, and may explain the lack of immunogenicity of non-mutated TAAs found in cancer patients. They suggest that exosomal targeting could enhance future anti-tumor vaccination protocols. This targeting exosome process could also be adapted for the development of more potent vaccines in some viral and parasitic diseases where the classical vaccine approach has demonstrated limitations. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Radioimmunoassay for tumor antigen of human cervical squamous cell carcinoma

    International Nuclear Information System (INIS)

    Kato, H.; Torigoe, T.

    1977-01-01

    A heterologous antiserum for human cervical squamous cell carcinoma was prepared and specificity determined by Ouchterlony immunodiffusion and immunofluorescence studies. With this antiserum, a tumor antigen was purified from human cervical squamous cell carcinoma tissue. The specificities of the antigen and the antiserum were then re-examined by a radioimmunoassay method using 125 I-labeled purified antigen. Although normal cervical tissue extract showed a moderate cross-reactivity in the radioimmunoassay, the circulating antigen activity could not be detected in normal women or in several patients with other carcinomas, whereas 27 of 35 patients with cervical squamous cell carcinoma showed detectable serum antigen activity. All patients with advanced stages of cervical squamous cell carcinoma showed detectable antigen levels. These results indicate that there is a quantitative abnormality, at least, of this tumor antigen in patients with cervical squamous cell carcinoma and that the radioimmunoassay for the antigen is a potentially useful tool in clinical care

  6. Evaluating the use of dedicated swab for rapid antigen detection ...

    African Journals Online (AJOL)

    Evaluating the use of dedicated swab for rapid antigen detection testing in group a ... African Journal of Clinical and Experimental Microbiology ... Several generations of rapid antigen detection tests (RADTs) have been developed to facilitate ...

  7. Cysteine proteases as potential antigens in antiparasitic DNA vaccines

    DEFF Research Database (Denmark)

    Jørgensen, Louise von Gersdorff; Buchmann, Kurt

    2011-01-01

    En litteraturgennemgang af muligheder for at bruge cystein proteaser som antigener i antiparasitære vacciner.......En litteraturgennemgang af muligheder for at bruge cystein proteaser som antigener i antiparasitære vacciner....

  8. Epstein-Barr virus nuclear antigen 2 specifically induces expression of the B-cell activation antigen CD23

    International Nuclear Information System (INIS)

    Wang, F.; Gregory, C.D.; Rowe, M.; Rickinson, A.B.; Wang, D.; Birkenbach, M.; Kikutani, H.; Kishimoto, T.; Kieff, E.

    1987-01-01

    Epstein-Barr virus (EBV) infection of EBV-negative Burkitt lymphoma (BL) cells includes some changes similar to those seen in normal B lymphocytes that have been growth transformed by EBV. The role of individual EBV genes in this process was evaluated by introducing each of the viral genes that are normally expressed in EBV growth-transformed and latently infected lymphoblasts into an EBV-negative BL cell line, using recombinant retrovirus-mediated transfer. Clones of cells were derived that stably express the EBV nuclear antigen 1 (EBNA-1), EBNA-2, EBNA-3, EBNA-leader protein, or EBV latent membrane protein (LMP). These were compared with control clones infected with the retrovirus vector. All 10 clones converted to EBNA-2 expression differed from control clones or clones expressing other EBV proteins by growth in tight clumps and by markedly increased expression of one particular surface marker of B-cell activation, CD23. Other activation antigens were unaffected by EBNA-2 expression, as were markers already expressed on the parent BL cell line. The results indicate that EBNA-2 is a specific direct or indirect trans-activator of CD23. This establishes a link between an EBV gene and cell gene expression. Since CD23 has been implicated in the transduction of B-cell growth signals, its specific induction by EBNA-2 could be important in EBV induction of B-lymphocyte transformation

  9. 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.)

  10. Potential radioimmunoassay system for detection of Hanganutziu-Deicher type heterophile antigen(s) and antibodies in tissues and fluids

    Energy Technology Data Exchange (ETDEWEB)

    Mukuria, J C; Naiki, Masaharu; Hashimoto, Masato; Nishiura, Katsumi; Okabe, Masahiro; Kato, Shiro

    1985-06-12

    A relatively simple, specific and sensitive radioimmunoassay system has been developed for the detection of heterophile Hanganutziu-Deicher (H-D) antigen(s) and antibodies. The SVI-labeled H-D antigen-active molecule used for the assay is a bovine erythrocyte major glycoprotein previously found to have a strong H-D antigen potency. Different H-D antigen-active molecules were compared for heterophile H-D antigen potency. Eight different lung cancer tissues were assayed for H-D antigen. The sera from the 8 lung cancer patients were also screened by ELISA and RIA in an attmept to correlate expression of H-D antigen on tissues with elevation of H-D antibodies.

  11. HLA antigens in juvenile onset diabetes.

    Science.gov (United States)

    Kikuchi, T; Toyota, T; Ouchi, E

    1980-11-01

    To study association between juvenile onset diabetes (JOD) and major histocompatibility gene complex, 40 patients with childhood onset diabetes and 120 healthy subjects were typed for HLA. Bw54 was present in 33 percent of the patients with JOD, while it appeared in 8 percent of the controls. Expressed as a relative risk, the antigen Bw54 confers a susceptibility to the development of JOD which is 5.3 times that in the controls. JOD shows a little high degree of association with A9 (78%). However, the A9-antigen is common in the Japanese and appears in 58 percent. Though less striking, the decreased frequency of B12 was 3 percent of JOD, less than 15 percent of the controls (p less than 0.05). There was no association between Bw54 and JOD with family history of diabetes.

  12. Radionuclide-labelled antigens in serological epidemiology

    International Nuclear Information System (INIS)

    Felsenfeld, O.; Parrott, M.W.

    1977-01-01

    The feasibility of tests using radionuclide-labelled antigens in serological surveys was studied, with particular attention to the likely availability of facilities and personnel in the tropics and arctics, where measurements may be disturbed by climatic influences. The methodology required was to be simple, rapid and suitable for examining large numbers of sera, as for epidemological surveys. In the introduction, limitations of labelled antigen tests are discussed, the choice of radionuclide and measurement methods, test procedures and evaluation of results. Collection, preservation and shipment of speciments (serum, faeces, cerebrospinal fluid, sputum, etc.) are described. Experiments with bacteria and bacterial toxins (Enterobacteriaceae, vibrios, staphylococci, meningococci, etc.), with protozoa and metazoa (Entamoeba hystolytica, Schistosoma mansoni, Trypanosoma cruzi, Plasmodia and other parasites), with viruses (vaccinia, adeno-, polio-, and influenza viruses, etc.), and with fungi are discussed

  13. Multiple genes encode the major surface glycoprotein of Pneumocystis carinii

    DEFF Research Database (Denmark)

    Kovacs, J A; Powell, F; Edman, J C

    1993-01-01

    The major surface antigen of Pneumocystis carinii, a life-threatening opportunistic pathogen in human immunodeficiency virus-infected patients, is an abundant glycoprotein that functions in host-organism interactions. A monoclonal antibody to this antigen is protective in animals, and thus this a...

  14. A competitive-inhibiton radioimmunoassay for influenza virus envelope antigens

    International Nuclear Information System (INIS)

    Russ, G.; Styk, B.; Vareckova, E.; Polakova, K.

    1976-01-01

    A double-antibody competitive-inhibition radioimmunoassay for influenza virus envelope antigens is described. A viral antigen preparation from influenza A virus recombinant MRC11 [antigenically identical to A/Port Chalmers/1/73 (H3N2)] consisting of haemagglutinin and neuraminidase was labelled with radioiodine. Rabbit antisera were allowed to react with the labelled antigen and the resultant antigen-antibody complexes were precipitated with the appropriate antiglobulin. The competitive-inhibition radioimmunoassay very sensitively elucidated differences even among closely related influenza virus strains. Attempts have been made to eliminate neuraminidase from radioimmunoprecipitation to obtain a competitive-inhibition radioimmunoassay system for haemagglutinin alone. (author)

  15. Antigen presentation and MHC class II expression by human esophageal epithelial cells: role in eosinophilic esophagitis.

    Science.gov (United States)

    Mulder, Daniel J; Pooni, Aman; Mak, Nanette; Hurlbut, David J; Basta, Sameh; Justinich, Christopher J

    2011-02-01

    Professional antigen-presenting cells (APCs) play a crucial role in initiating immune responses. Under pathological conditions, epithelial cells at mucosal surfaces act as nonprofessional APCs, thereby regulating immune responses at the site of exposure. Epithelial cells in the esophagus may contribute to the pathogenesis of eosinophilic esophagitis (EoE) by presenting antigens on the major histocompatibility complex (MHC) class II. Our goal was to demonstrate the ability of esophageal epithelial cells to process and present antigens on the MHC class II system and to investigate the contribution of epithelial cell antigen presentation to EoE. Immunohistochemistry detected HLA-DR, CD80, and CD86 expression and enzyme-linked immunosorbent assay detected interferon-γ (IFNγ) in esophageal biopsies. Antigen presentation was studied using the human esophageal epithelial cell line HET-1A by reverse transcriptase-PCR, flow cytometry, and confocal microscopy. T helper cell lymphocyte proliferation was assessed by flow cytometry and IL-2 secretion. IFNγ and MHC class II were increased in mucosa of patients with EoE. IFNγ increased mRNA of HLA-DP, HLA-DQ, HLA-DR, and CIITA in HET-1A cells. HET-1A engulfed cell debris and processed ovalbumin. HET-1A cells expressed HLA-DR after IFNγ treatment. HET-1A stimulated T helper cell activation. In this study, we demonstrated the ability of esophageal epithelial cells to act as nonprofessional APCs in the presence of IFNγ. Esophageal epithelial cell antigen presentation may contribute to the pathophysiology of eosinophilic esophagitis. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  16. Presenting Influenza A M2e Antigen on Recombinant Spores of Bacillus subtilis.

    Directory of Open Access Journals (Sweden)

    Tomasz Łęga

    Full Text Available Effective vaccination against influenza virus infection is a serious problem mainly due to antigenic variability of the virus. Among many of investigated antigens, the extracellular domain of the M2 protein (M2e features high homology in all strains of influenza A viruses and antibodies against M2e and is protective in animal models; this makes it a potential candidate for generation of a universal influenza vaccine. However, due to the low immunogenicity of the M2e, formulation of a vaccine based on this antigen requires some modification to induce effective immune responses. In this work we evaluated the possible use of Bacillus subtilis spores as a carrier of the Influenza A M2e antigen in mucosal vaccination. A tandem repeat of 4 consensus sequences coding for human-avian-swine-human M2e (M2eH-A-S-H peptide was fused to spore coat proteins and stably exposed on the spore surface, as demonstrated by the immunostaining of intact, recombinant spores. Oral immunization of mice with recombinant endospores carrying M2eH-A-S-H elicited specific antibody production without the addition of adjuvants. Bacillus subtilis endospores can serve as influenza antigen carriers. Recombinant spores constructed in this work showed low immunogenicity although were able to induce antibody production. The System of influenza antigen administration presented in this work is attractive mainly due to the omitting time-consuming and cost-intensive immunogen production and purification. Therefore modification should be made to increase the immunogenicity of the presented system.

  17. Screening for epitope specificity directly on culture supernatants in the early phase of monoclonal antibody production by an ELISA with biotin-labeled antigen.

    Science.gov (United States)

    Andersen, Ditte C; Jensen, Charlotte H; Gregersen, Annemette; Brandt, Jette; Kliem, Anette; Skjødt, Karsten; Koch, Claus; Teisner, Børge

    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 advantages using this assay, are that it can be performed directly on culture supernatants in the early phase of monoclonal antibody production, and also works for antigens with repetitive epitopes. Moreover, the bonus effect, i.e., a signal in excess of the reference signal when sets of monoclonal antibodies with different epitope specificity are compared, gives a relative measure of affinity.

  18. Cancer Patient T Cells Genetically Targeted to Prostate-Specific Membrane Antigen Specifically Lyse Prostate Cancer Cells and Release Cytokines in Response to Prostate-Specific Membrane Antigen

    Directory of Open Access Journals (Sweden)

    Michael C. Gong

    1999-06-01

    Full Text Available The expression of immunoglobulin-based artificial receptors in normal T lymphocytes provides a means to target lymphocytes to cell surface antigens independently of major histocompatibility complex restriction. Such artificial receptors have been previously shown to confer antigen-specific tumoricidal properties in murine T cells. We constructed a novel ζ chain fusion receptor specific for prostate-specific membrane antigen (PSMA termed Pz-1. PSMA is a cell-surface glycoprotein expressed on prostate cancer cells and the neovascular endothelium of multiple carcinomas. We show that primary T cells harvested from five of five patients with different stages of prostate cancer and transduced with the Pz-1 receptor readily lyse prostate cancer cells. Having established a culture system using fibroblasts that express PSMA, we next show that T cells expressing the Pz-1 receptor release cytokines in response to cell-bound PSMA. Furthermore, we show that the cytokine release is greatly augmented by B7.1-mediated costimulation. Thus, our findings support the feasibility of adoptive cell therapy by using genetically engineered T cells in prostate cancer patients and suggest that both CD4+ and CD8+ T lymphocyte functions can be synergistically targeted against tumor cells.

  19. Polyclonal antibodies for the detection of Trypanosoma cruzi circulating antigens.

    Directory of Open Access Journals (Sweden)

    Edith S Málaga-Machaca

    2017-11-01

    Full Text Available Detection of Trypanosoma cruzi antigens in clinical samples is considered an important diagnostic tool for Chagas disease. The production and use of polyclonal antibodies may contribute to an increase in the sensitivity of immunodiagnosis of Chagas disease.Polyclonal antibodies were raised in alpacas, rabbits, and hens immunized with trypomastigote excreted-secreted antigen, membrane proteins, trypomastigote lysate antigen and recombinant 1F8 to produce polyclonal antibodies. Western blot analysis was performed to determine specificity of the developed antibodies. An antigen capture ELISA of circulating antigens in serum, plasma and urine samples was developed using IgY polyclonal antibodies against T. cruzi membrane antigens (capture antibody and IgG from alpaca raised against TESA. A total of 33 serum, 23 plasma and 9 urine samples were analyzed using the developed test. Among serum samples, compared to serology, the antigen capture ELISA tested positive in 55% of samples. All plasma samples from serology positive subjects were positive in the antigen capture ELISA. All urine positive samples had corresponding plasma samples that were also positive when tested by the antigen capture ELISA.Polyclonal antibodies are useful for detection of circulating antigens in both the plasma and urine of infected individuals. Detection of antigens is direct evidence of the presence of the parasite, and could be a better surrogate of current infection status.

  20. Ultraviolet light-induced suppression of antigen presentation

    International Nuclear Information System (INIS)

    Spellman, C.W.; Tomasi, T.B.

    1983-01-01

    Ultraviolet (UV) light irradiation of animals results in the development of specific T suppressor cells that inhibit antitumor immune responses. It is thought that suppression may arise as a consequence of altered antigen presentation by UV-irradiated epidermal cells. This hypothesis is based on evidence demonstrating that specific lymphoid tissues from UV-irradiated hosts exhibit impaired antigen-presenting function and that animals cannot be contact sensitized when antigens are applied to a UV-irradiated skin site. Langerhans cells of the skin are likely candidates as targets of UV-induced defects in antigen presentation as they bear Fc and C3b receptors, express Ia antigens, are of bone marrow origin, and are capable of presenting antigen in vitro. We speculate on the possible clinical usefulness of UV-induced tolerance to specific antigens such as those encountered in monoclonal antibody therapy and tissue transplantation

  1. Review of Mycobacteriumavium subsp. paratuberculosis antigen candidates with diagnostic potential

    DEFF Research Database (Denmark)

    Mikkelsen, Heidi; Aagaard, Claus; Nielsen, Søren Saxmose

    2011-01-01

    antigens, heat shock antigens and hypothetical antigens. Strategies for evaluation of novel antigen candidates are discussed critically. Relatively few of the described antigens were evaluated for their use in CMI based diagnostic assays and so far, no obvious candidate has been identified...... to development of antibodies and shedding of detectable amounts of MAP. At present, available diagnostic assays are limited by the lack of MAP specific antigens included in these assays resulting in poor specificity. The objective of this review is to provide a systematic overview of diagnostic MAP antigen...... faeces; however, these diagnostic tools are often not applicable until years after infection. Detection of MAP specific cell-mediated immune (CMI) responses can serve as an alternative and be implemented in a diagnostic tool. CMI responses can be measured at an early stage of infection, prior...

  2. Structure-function analysis of the self-recognizing Antigen 43 autotransporter protein from Escherichia coli

    DEFF Research Database (Denmark)

    Klemm, Per; Hjerrild, L.; Gjermansen, Morten

    2004-01-01

    Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Expression of Ag43 confers aggregation and fluffing of cells, promotes biofilm formation and is associated with enhanced resistance to antimicrobial agents. Ag43 is an autotransporter protein and consi......Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Expression of Ag43 confers aggregation and fluffing of cells, promotes biofilm formation and is associated with enhanced resistance to antimicrobial agents. Ag43 is an autotransporter protein......-clumping variants, we have pinpointed the region of the protein responsible for autoaggregation to be located within the N-terminal one-third of the passenger domain. Our data suggest that ionic interactions between charged residues residing in interacting pairs of Ag43(alpha) domains may be important for the self...

  3. Toward low-cost affinity reagents: lyophilized yeast-scFv probes specific for pathogen antigens.

    Directory of Open Access Journals (Sweden)

    Sean A Gray

    Full Text Available The generation of affinity reagents, usually monoclonal antibodies, remains a critical bottleneck in biomedical research and diagnostic test development. Recombinant antibody-like proteins such as scFv have yet to replace traditional monoclonal antibodies in antigen detection applications, in large part because of poor performance of scFv in solution. To address this limitation, we have developed assays that use whole yeast cells expressing scFv on their surfaces (yeast-scFv in place of soluble purified scFv or traditional monoclonal antibodies. In this study, a nonimmune library of human scFv displayed on the surfaces of yeast cells was screened for clones that bind to recombinant cyst proteins of Entamoeba histolytica, an enteric pathogen of humans. Selected yeast-scFv clones were stabilized by lyophilization and used in detection assay formats in which the yeast-scFv served as solid support-bound monoclonal antibodies. Specific binding of antigen to the yeast-scFv was detected by staining with rabbit polyclonal antibodies. In flow cytometry-based assays, lyophilized yeast-scFv reagents retained full binding activity and specificity for their cognate antigens after 4 weeks of storage at room temperature in the absence of desiccants or stabilizers. Because flow cytometry is not available to all potential assay users, an immunofluorescence assay was also developed that detects antigen with similar sensitivity and specificity. Antigen-specific whole-cell yeast-scFv reagents can be selected from nonimmune libraries in 2-3 weeks, produced in vast quantities, and packaged in lyophilized form for extended shelf life. Lyophilized yeast-scFv show promise as low cost, renewable alternatives to monoclonal antibodies for diagnosis and research.

  4. Plasmodium falciparum variant STEVOR antigens are expressed in merozoites and possibly associated with erythrocyte invasion

    Directory of Open Access Journals (Sweden)

    Petter Michaela

    2008-07-01

    Full Text Available Abstract Background Plasmodium falciparum STEVOR proteins, encoded by the multicopy stevor gene family have no known biological functions. Their expression and unique locations in different parasite life cycle stages evoke multiple functionalities. Their abundance and hypervariability support a role in antigenic variation. Methods Immunoblotting of total parasite proteins with an anti-STEVOR antibody was used to identify variant antigens of this gene family and to follow changes in STEVOR expression in parasite populations panned on CSA or CD36 receptors. Immunofluorescence assays and immunoelectron microscopy were performed to study the subcellular localization of STEVOR proteins in different parasite stages. The capacity of the antibody to inhibit merozoite invasion of erythrocytes was assessed to determine whether STEVOR variants were involved in the invasion process. Results Antigenic variation of STEVORs at the protein level was observed in blood stage parasites. STEVOR variants were found to be present on the merozoite surface and in rhoptries. An insight into a participation in erythrocyte invasion was gained through an immunofluorescence analysis of a sequence of thin slides representing progressive steps in erythrocyte invasion. An interesting feature of the staining pattern was what appeared to be the release of STEVORs around the invading merozoites. Because the anti-STEVOR antibody did not inhibit invasion, the role of STEVORs in this process remains unknown. Conclusion The localization of STEVOR proteins to the merozoite surface and the rhoptries together with its prevalence as a released component in the invading merozoite suggest a role of these antigens in adhesion and/or immune evasion in the erythrocyte invasion process. These observations would also justify STEVORs for undergoing antigenic variation. Even though a role in erythrocyte invasion remains speculative, an association of members of the STEVOR protein family with

  5. Inactivation and purification of cowpea mosaic virus-like particles displaying peptide antigens from Bacillus anthracis

    OpenAIRE

    Phelps, Jamie P.; Dang, Nghiep; Rasochova, Lada

    2007-01-01

    Chimeric cowpea mosaic virus (CPMV) particles displaying foreign peptide antigens on the particle surface are suitable for development of peptide-based vaccines. However, commonly used PEG precipitation-based purification methods are not sufficient for production of high quality vaccine candidates because they do not allow for separation of chimeric particles from cleaved contaminating species. Moreover, the purified particles remain infectious to plants. To advance the CPMV technology furthe...

  6. Means for use in radioimmunodetection of an antigen-antibody reaction

    International Nuclear Information System (INIS)

    Reynolds, J.H.

    1983-01-01

    A unitized, solid phase kit for radioimmunoassay is described. All of the necessary assay reagents are incorporated in a single tube. Requiring only the addition of the patient's sample, all phases of the assay procedure are performed in this tube. Antibodies are bound to the tube surface, while labelled antigens are also present but unbound. Storage in the absence of air and water results in the stabilization of the reagents such that the system can be stored for long periods

  7. Guinea pig Ia antigens are not derivatised on trinitrophenyl-modified cells

    Energy Technology Data Exchange (ETDEWEB)

    Clement, L T; Thomas, D W; Kask, A M; Shevach, E M [National Inst. of Allergy and Infectious Diseases, Bethesda, MD (USA)

    1978-08-10

    In an effort to clarify the nature of the trinitrophenyl (TNP) specific immunogen recognised by hapten-reactive guinea pig T lymphocytes, the membrane proteins of TNP-modified guinea pig macrophages have been analysed by chemical methods using nitrobenzene sulphonic acid surface labelled with /sup 125/I. The experiments provided strong evidence that the TNP specific immunogen which T lymphocytes recognise on guinea pig macrophages does not consist of directly haptenated Ia antigens.

  8. Molecular Characteristics of Carcinoembryonic Antigen and Nonspecific Cross-reacting Antigen(Clinical Application of Tumor Antigen)

    OpenAIRE

    内山, 一晃; Uchiyama, Kazuaki

    1990-01-01

    Carcinoembryonic antigen (CEA) is one of the most famous laboratory tests of tumor markers. CEA was first reported in 1965, but molecular structure of CEA was not clear untill recent years. Amino acid sequence of CEA was reported in 1987, by the success of cDNA clonig of CEA. The CEA molecule is composed of five major domains, called domain N, I, II, III, C from the -NH_2 terminal. But sugar chains of CEA are complicated and have much variety, so there are few informations about them. If CEA ...

  9. Blood group antigen studies using CdTe quantum dots and flow cytometry

    Directory of Open Access Journals (Sweden)

    Cabral Filho PE

    2015-07-01

    Full Text Available Paulo E Cabral Filho,1 Maria IA Pereira,1 Heloise P Fernandes,2 Andre A de Thomaz,3 Carlos L Cesar,3 Beate S Santos,4 Maria L Barjas-Castro,2 Adriana Fontes1 1Departamento de Biofísica e Radiobiologia, Universidade Federal de Pernambuco, Recife, Pernambuco, 2Centro de Hematologia e Hemoterapia, Universidade Estadual de Campinas, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, 3Departamento de Eletrônica Quântica, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, São Paulo, 4Departamento de Ciências Farmacêuticas, Universidade Federal de Pernambuco, Recife, PE, Brazil Abstract: New methods of analysis involving semiconductor nanocrystals (quantum dots [QDs] as fluorescent probes have been highlighted in life science. QDs present some advantages when compared to organic dyes, such as size-tunable emission spectra, broad absorption bands, and principally exceptional resistance to photobleaching. Methods applying QDs can be simple, not laborious, and can present high sensibility, allowing biomolecule identification and quantification with high specificity. In this context, the aim of this work was to apply dual-color CdTe QDs to quantify red blood cell (RBC antigen expression on cell surface by flow cytometric analysis. QDs were conjugated to anti-A or anti-B monoclonal antibodies, as well as to the anti-H (Ulex europaeus I lectin, to investigate RBCs of A1, B, A1B, O, A2, and Aweak donors. Bioconjugates were capable of distinguishing the different expressions of RBC antigens, both by labeling efficiency and by flow cytometry histogram profile. Furthermore, results showed that RBCs from Aweak donors present fewer amounts of A antigens and higher amounts of H, when compared to A1 RBCs. In the A group, the amount of A antigens decreased as A1 > A3 > AX = Ael, while H antigens were AX = Ael > A1. Bioconjugates presented stability and remained active for at least 6 months. In conclusion

  10. Screening of random peptide library of hemagglutinin from pandemic 2009 A(H1N1 influenza virus reveals unexpected antigenically important regions.

    Directory of Open Access Journals (Sweden)

    Wanghui Xu

    Full Text Available The antigenic structure of the membrane protein hemagglutinin (HA from the 2009 A(H1N1 influenza virus was dissected with a high-throughput screening method using complex antisera. The approach involves generating yeast cell libraries displaying a pool of random peptides of controllable lengths on the cell surface, followed by one round of fluorescence-activated cell sorting (FACS against antisera from mouse, goat and human, respectively. The amino acid residue frequency appearing in the antigenic peptides at both the primary sequence and structural level was determined and used to identify "hot spots" or antigenically important regions. Unexpectedly, different antigenic structures were seen for different antisera. Moreover, five antigenic regions were identified, of which all but one are located in the conserved HA stem region that is responsible for membrane fusion. Our findings are corroborated by several recent studies on cross-neutralizing H1 subtype antibodies that recognize the HA stem region. The antigenic peptides identified may provide clues for creating peptide vaccines with better accessibility to memory B cells and better induction of cross-neutralizing antibodies than the whole HA protein. The scheme used in this study enables a direct mapping of the antigenic regions of viral proteins recognized by antisera, and may be useful for dissecting the antigenic structures of other viral proteins.

  11. Abnormal antigens in breast cancer tissues and production of monoclonal antibodies against one of these antigens

    International Nuclear Information System (INIS)

    Mohammed, M. E. A.

    2010-02-01

    Breast cancer is associated with up regulation, down regulation of normal antigens or abnormal antigens. These antigens are very useful candidates as targets for the different breast cancer therapies and for vaccination trials. This study was done to characterize abnormal antigens, extract one of them and to produce monoclonal antibodies against the extracted antigen. One hundred and twenty Sudanese female patients were included in this study after informed consent. The mean age was 47. 2 years (16-80). Two tissue samples were obtained from each patient and they were confirmed as normal and cancerous breast tissues microscopically. 2D PAGE was used to analyze the protein content of samples. LC/MS and nr. fast a database search were used for separation and indentification of the abnormal proteins. Three different patterns of 2D Page results were obtained, the first pattern involved detection of four abnormal proteins in 26.7% of the patient cancerous tissues while they were undetected in the normal tissues of the same patients. In the second 2D PAGE result pattern the cancerous and the normal tissues of 67.5% patients were identical and they did not contain the four abnormal proteins while the third 2D PAGE pattern involved the presence of two abnormal antigens (from the four) in the cancerous tissues of 5.8% of the patients and they were absent from the normal tissues of the same patients. The four abnormal proteins were identified as, human Thioredoxin (D60nmutant), x-ray crystal structure of human galectin-1, retrocopy of tropomyosin 3(rc TPM3) and beta-tropomyosin (isoform 2). The primary and the secondary structures were obtained from the SWISSPROT and the PDB databases. Beta tropomyosin spot was extracted and used as antigen for monoclonal antibody production. Monoclonal antibody against beta- tropomyosin with a concentration of 0.35 mg/ml and a G11 anti beta-tropomyosin hybridoma cell line were produced. The monoclonal antibody was with single bad and

  12. Abnormal antigens in breast cancer tissues and production of monoclonal antibodies against one of these antigens

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, M E. A. [University of Khartoum, Khartoum (Sudan)

    2010-02-15

    Breast cancer is associated with up regulation, down regulation of normal antigens or abnormal antigens. These antigens are very useful candidates as targets for the different breast cancer therapies and for vaccination trials. This study was done to characterize abnormal antigens, extract one of them and to produce monoclonal antibodies against the extracted antigen. One hundred and twenty Sudanese female patients were included in this study after informed consent. The mean age was 47. 2 years (16-80). Two tissue samples were obtained from each patient and they were confirmed as normal and cancerous breast tissues microscopically. 2D PAGE was used to analyze the protein content of samples. LC/MS and nr. fast a database search were used for separation and indentification of the abnormal proteins. Three different patterns of 2D Page results were obtained, the first pattern involved detection of four abnormal proteins in 26.7% of the patient cancerous tissues while they were undetected in the normal tissues of the same patients. In the second 2D PAGE result pattern the cancerous and the normal tissues of 67.5% patients were identical and they did not contain the four abnormal proteins while the third 2D PAGE pattern involved the presence of two abnormal antigens (from the four) in the cancerous tissues of 5.8% of the patients and they were absent from the normal tissues of the same patients. The four abnormal proteins were identified as, human Thioredoxin (D60nmutant), x-ray crystal structure of human galectin-1, retrocopy of tropomyosin 3(rc TPM3) and beta-tropomyosin (isoform 2). The primary and the secondary structures were obtained from the SWISSPROT and the PDB databases. Beta tropomyosin spot was extracted and used as antigen for monoclonal antibody production. Monoclonal antibody against beta- tropomyosin with a concentration of 0.35 mg/ml and a G11 anti beta-tropomyosin hybridoma cell line were produced. The monoclonal antibody was with single bad and

  13. Immunoliposome-PCR: a generic ultrasensitive quantitative antigen detection system

    Directory of Open Access Journals (Sweden)

    He Junkun

    2012-06-01

    Full Text Available Abstract Background The accurate quantification of antigens at low concentrations over a wide dynamic range is needed for identifying biomarkers associated with disease and detecting protein interactions in high-throughput microarrays used in proteomics. Here we report the development of an ultrasensitive quantitative assay format called immunoliposome polymerase chain reaction (ILPCR that fulfills these requirements. This method uses a liposome, with reporter DNA encapsulated inside and biotin-labeled polyethylene glycol (PEG phospholipid conjugates incorporated into the outer surface of the liposome, as a detection reagent. The antigenic target is immobilized in the well of a microplate by a capture antibody and the liposome detection reagent is then coupled to a biotin-labeled second antibody through a NeutrAvidin bridge. The liposome is ruptured to release the reporter DNA, which serves as a surrogate to quantify the protein target using real-time PCR. Results A liposome detection reagent was prepared, which consisted of a population of liposomes ~120 nm in diameter with each liposome possessing ~800 accessible biotin receptors and ~220 encapsulated reporters. This liposome detection reagent was used in an assay to quantify the concentration of carcinoembryonic antigen (CEA in human serum. This ILPCR assay exhibited a linear dose–response curve from 10-10 M to 10-16 M CEA. Within this range the assay coefficient of variance was Conclusions The ILPCR assay has several advantages over other immuno-PCR methods. The reporter DNA and biotin-labeled PEG phospholipids spontaneously incorporate into the liposomes as they form, simplifying preparation of the detection reagent. Encapsulation of the reporter inside the liposomes allows nonspecific DNA in the assay medium to be degraded with DNase I prior to quantification of the encapsulated reporter by PCR, which reduces false-positive results and improves quantitative accuracy. The ability to

  14. Nuclear lamins and peripheral nuclear antigens during fertilization and embryogenesis in mice and sea urchins

    Science.gov (United States)

    Schatten, G.; Schatten, H.; Simerly, C.; Maul, G. G.; Chaly, N.

    1985-01-01

    Nuclear structural changes during fertilization and embryogenesis in mice and sea urchins are traced using four antibodies. The oocytes from virgin female mice, morulae and blastocytes from mated females, and gametes from the sea urchin Lytechnius variegatis are studied using mouse monoclonal antibodies to nuclear lamin A/C, monoclonal antibody to P1, human autoimmune antibodies to lamin A/C, and to lamin B. The mouse fertilization data reveal no lamins on the oocyte; however, lamins are present on the pronuclei, and chromosomes are found on the oocytes and pronuclei. It is detected that on the sea urchin sperm the lamins are reduced to acrosomal and centriolar fossae and peripheral antigens are around the sperm nucleus. The mouse sperm bind lamin antibodies regionally and do not contain antigens. Lamins and antigens are observed on both pronuclei and chromosomes during sea urchin fertilization. Mouse embryogenesis reveals that lamin A/C is not recognized at morula and blastocyst stages; however, lamin B stains are retained. In sea urchin embryogenesis lamin recognition is lost at the blastrula, gastrula, and plutei stages. It is noted that nuclear lamins lost during spermatogenesis are restored at fertilization and peripheral antigens are associated with the surface of chromosomes during meiosis and mitosis and with the periphery of the pronuclei and nuclei during interphase.

  15. A procedure for the radioimmunochemical determination of antigens with different structures

    International Nuclear Information System (INIS)

    Galoci, J.; Machan, V.

    1990-01-01

    To a solution of a specific antibody, its antigen labelled with iodine 125, and of the unknown sample is added animal (e.g., goat) antibody against rabbit immunoglobulin immobilized on modified microcrystalline cellulose; always the same quantities are applied always for the same time. After incubation for 1 hr at 20 degC, the immunochemical complex formed is centrifuged and its radioactivity is measured, and the amount of the antigen in sample is determined by comparison with standards. The procedure is applicable to antigens with any structure. Assets of the separating system include a very good stability in solution, a low value of nonspecific bonding and a low sedimentation velocity of the particles used. The procedure is well suited to the quantitation of antigens present in very low concentrations in blood serum, urine, milk, and extracts from tissues or animal feed. In a modification of the procedure, the animal antibody against rabbit immunoglobulin is immobilized on the surface of modified cellulose particles 5 to 15 μm in size exhibiting a very low sedimentation velocity, activated with 1,1-carbonyldiimidazole. (M.D.)

  16. A nonself sugar mimic of the HIV glycan shield shows enhanced antigenicity

    Energy Technology Data Exchange (ETDEWEB)

    Doores, Katie J.; Fulton, Zara; Hong, Vu; Patel, Mitul K.; Scanlan, Christopher N.; Wormald, Mark R.; Finn, M.G.; Burton, Dennis R.; Wilson, Ian A.; Davis, Benjamin G. (Scripps); (Oxford)

    2011-08-24

    Antibody 2G12 uniquely neutralizes a broad range of HIV-1 isolates by binding the high-mannose glycans on the HIV-1 surface glycoprotein, gp120. Antigens that resemble these natural epitopes of 2G12 would be highly desirable components for an HIV-1 vaccine. However, host-produced (self)-carbohydrate motifs have been unsuccessful so far at eliciting 2G12-like antibodies that cross-react with gp120. Based on the surprising observation that 2G12 binds nonproteinaceous monosaccharide D-fructose with higher affinity than D-mannose, we show here that a designed set of nonself, synthetic monosaccharides are potent antigens. When introduced to the terminus of the D1 arm of protein glycans recognized by 2G12, their antigenicity is significantly enhanced. Logical variation of these unnatural sugars pinpointed key modifications, and the molecular basis of this increased antigenicity was elucidated using high-resolution crystallographic analyses. Virus-like particle protein conjugates containing such nonself glycans are bound more tightly by 2G12. As immunogens they elicit higher titers of antibodies than those immunogenic conjugates containing the self D1 glycan motif. These antibodies generated from nonself immunogens also cross-react with this self motif, which is found in the glycan shield, when it is presented in a range of different conjugates and glycans. However, these antibodies did not bind this glycan motif when present on gp120.

  17. Function and Dynamics of Tetraspanins during Antigen Recognition and Immunological Synapse Formation

    Directory of Open Access Journals (Sweden)

    Vera eRocha-Perugini

    2016-01-01

    Full Text Available Tetraspanin-enriched microdomains (TEMs are specialized membrane platforms driven by protein-protein interactions that integrate membrane receptors and adhesion molecules. Tetraspanins participate in antigen recognition and presentation by antigen presenting cells (APCs through the organization of pattern recognition receptors (PRRs and their downstream induced-signaling, as well as the regulation of MHC-II-peptide trafficking. T lymphocyte activation is triggered upon specific recognition of antigens present on the APC surface during immunological synapse (IS formation. This dynamic process is characterized by a defined spatial organization involving the compartmentalization of receptors and adhesion molecules in specialized membrane domains that are connected to the underlying cytoskeleton and signaling molecules. Tetraspanins contribute to the spatial organization and maturation of the IS by controlling receptor clustering and local accumulation of adhesion receptors and integrins, their downstream signaling and linkage to the actin cytoskeleton. This review offers a perspective on the important role of TEMs in the regulation of antigen recognition and presentation, and in the dynamics of IS architectural organization.

  18. Antibodies to a common outer envelope antigen of Treponema hyodysenteriae with antibacterial activity.

    Science.gov (United States)

    Sellwood, R; Kent, K A; Burrows, M R; Lysons, R J; Bland, A P

    1989-08-01

    Outer envelopes of Treponema hyodysenteriae strains P18A and VS1 were prepared and characterized by SDS-PAGE. In Western blot analysis of eleven strains of T. hyodysenteriae and two intestinal non-pathogenic spirochaetes, polyclonal antiserum raised to the outer envelopes of strain P18A contained antibodies primarily to two polypeptides. A 45 kDa polypeptide was present in only two strains of T. hyodysenteriae, P18A and MC52/80, whereas another antigen of 16 kDa was common to all eleven strains of T. hyodysenteriae but was not present in the two nonpathogens. Immunogold labelling of whole organisms suggested that the 16 kDa antigen was present on the surface of the spirochaetes. In in vitro tests the serum agglutinated and inhibited growth of only the T. hyodysenteriae strains, suggesting that antibodies to the 16 kDa antigen were responsible for these activities. Serum from a gnotobiotic pig infected with T. hyodysenteriae strain P18A had antibodies to the 16 kDa antigen alone and also possessed agglutinating and growth-inhibitory activities.

  19. Function and Dynamics of Tetraspanins during Antigen Recognition and Immunological Synapse Formation

    Science.gov (United States)

    Rocha-Perugini, Vera; Sánchez-Madrid, Francisco; Martínez del Hoyo, Gloria

    2016-01-01

    Tetraspanin-enriched microdomains (TEMs) are specialized membrane platforms driven by protein–protein interactions that integrate membrane receptors and adhesion molecules. Tetraspanins participate in antigen recognition and presentation by antigen-­presenting cells (APCs) through the organization of pattern-recognition receptors (PRRs) and their downstream-induced signaling, as well as the regulation of MHC-II–peptide trafficking. T lymphocyte activation is triggered upon specific recognition of antigens present on the APC surface during immunological synapse (IS) formation. This dynamic process is characterized by a defined spatial organization involving the compartmentalization of receptors and adhesion molecules in specialized membrane domains that are connected to the underlying cytoskeleton and signaling molecules. Tetraspanins contribute to the spatial organization and maturation of the IS by controlling receptor clustering and local accumulation of adhesion receptors and integrins, their downstream signaling, and linkage to the actin cytoskeleton. This review offers a perspective on the important role of TEMs in the regulation of antigen recognition and presentation and in the dynamics of IS architectural organization. PMID:26793193

  20. Identification of variant-specific surface proteins in Giardia muris trophozoites.

    Science.gov (United States)

    Ropolo, Andrea S; Saura, Alicia; Carranza, Pedro G; Lujan, Hugo D

    2005-08-01

    Giardia lamblia undergoes antigenic variation, a process that might allow the parasite to evade the host's immune response and adapt to different environments. Here we show that Giardia muris, a related species that naturally infects rodents, possesses multiple variant-specific surface proteins (VSPs) and expresses VSPs on its surface, suggesting that it undergoes antigenic variation similar to that of G. lamblia.

  1. Identification of Variant-Specific Surface Proteins in Giardia muris Trophozoites

    OpenAIRE

    Ropolo, Andrea S.; Saura, Alicia; Carranza, Pedro G.; Lujan, Hugo D.

    2005-01-01

    Giardia lamblia undergoes antigenic variation, a process that might allow the parasite to evade the host's immune response and adapt to different environments. Here we show that Giardia muris, a related species that naturally infects rodents, possesses multiple variant-specific surface proteins (VSPs) and expresses VSPs on its surface, suggesting that it undergoes antigenic variation similar to that of G. lamblia.

  2. Cell membrane antigen-antibody complex dissociation by the widely used glycine-HCL method: an unreliable procedure for studying antibody internalization.

    Science.gov (United States)

    Tsaltas, G; Ford, C H

    1993-02-01

    Methods following the process of binding and internalization of antibodies to cell surface antigens have often employed low pH isoosmolar buffers in order to dissociate surface antigen-antibody complexes. One of the most widely used buffers is a 0.05 M glycine-HCL buffer pH 2.8. Since the efficacy of action of this buffer was critical to a series of internalization experiments employing monoclonal antibodies (Mabs) to carcinoembryonic antigen (CEA) expressing cancer cell lines in this laboratory, we tested its performance in a number of different assays. Our results indicate that this buffer only partially dissociates antigen-antibody bonds and therefore can introduce major inaccuracies in internalization experiments.

  3. Kinetics of human T-cell expression of LFA-1, IL-2 receptor, and ICAM-1 following antigenic stimulation in vitro

    DEFF Research Database (Denmark)

    Hviid, L; Felsing, A; Theander, T G

    1993-01-01

    -specific stimulation is available. In the present study we have examined phenotypic T-cell changes after in vitro stimulation by the antigens purified derivative of tuberculin (PPD) and tetanus toxoid (TT). We show that the well-established differences in kinetics of mitogen- and antigen-induced T-cell proliferation...... of all 3 surface antigens showed similar kinetics, and correlated with the magnitude of the lymphoproliferative response. By day 8 (PHA-stimulation) or day 12 (PPD or TT stimulation), the lymphoproliferative response was essentially completed, the expression of CD11a and CD54 had approached...

  4. Varicellovirus UL49.5 proteins differentially affect the function of the transporter associated with antigen processing, TAP

    NARCIS (Netherlands)

    Koppers-Lalic, D.; Verweij, M.C.; Lipinska, A.D.; Wang, Y.; Quinten, E.; Reits, E.A.; Koch, J.; Loch, S.; Rezende, M.M.; Daus, F.J.; Bienkowska-Szewczyk, K.; Osterrieder, N.; Mettenleiter, T.C.; Heemskerk, M.H.M.; Tampe, R.; Neefjes, J.J.; Chowdhury, S.I.; Ressing, M.E.; Rijsewijk, F.A.M.; Wiertz, E.J.H.J.

    2008-01-01

    Cytotoxic T-lymphocytes play an important role in the protection against viral infections, which they detect through the recognition of virus-derived peptides, presented in the context of MHC class I molecules at the surface of the infected cell. The transporter associated with antigen processing

  5. The molecular determinants of antibody recognition and antigenic drift in the H3 hemagglutinin of swine influenza A virus

    Science.gov (United States)

    Influenza A virus (IAV) of the H3 subtype is an important pathogen that affects both humans and swine. The main intervention strategy for preventing infection is vaccination to induce neutralizing antibodies against the surface glycoprotein hemagglutinin (HA). However, due to antigenic drift, vaccin...

  6. Prostate specific antigen and its clinical application

    International Nuclear Information System (INIS)

    Xu Yang

    2000-01-01

    Prostate-Specific Antigen (PSA), a serine proteases, is a glycoprotein consisting of a single polypeptide chain. Secreted exclusively by epithelial cells of the prostate gland, PSA is found largely in seminal plasma. Only a small amount of PSA can be found in normal serum. Serum PSA levels are found to be, considerably increased in prostate cancer patients. A number of studies on PSA have made great achievement on its biochemistry, analytical method and clinical application. PSA as one of the most important tumor marker, is used to help diagnosis and monitor the therapeutic efficacy of prostate cancer

  7. Interference of heparin in carcinoembryonic antigen radioimmunoassays

    International Nuclear Information System (INIS)

    Wu, J.T.

    1983-01-01

    A false Roche carcinoembryonic antigen (CEA) activity could be detected in all commercial and noncommercial heparin preparations examined. The possibility of 'due to contamination' has been ruled out. Using the Roche procedure, heparin solutions, in the absence of CEA, gave positive CEA activity; on the other hand, no CEA activity was detected in solutions containing only heparin when the Abbott Kit was used. When heparin was present in specimens containing CEA, the Abbott Kit underestimated the CEA activity, whereas the Roche Kit gave false elevated values. However, the negative effect of heparin could be reduced by heat treatment in the presence of plasma proteins. (Auth.)

  8. Antigen Presentation Keeps Trending in Immunotherapy Resistance.

    Science.gov (United States)

    Kalbasi, Anusha; Ribas, Antoni

    2018-04-19

    Through a gain-of-function kinome screen, MEX3B was identified as a mediator of resistance to T-cell immunotherapy not previously identified using CRISPR-based screens. MEX3B is a posttranscriptional regulator of HLA-A, validating the critical role of tumor-intrinsic antigen presentation in T-cell immunotherapy and indicating a new putative molecular target. Clin Cancer Res; 24(14); 1-3. ©2018 AACR. See related article by Huang et al., p. xxxx . ©2018 American Association for Cancer Research.

  9. Traffic pathways of Plasmodium vivax antigens during intraerythrocytic parasite development.

    Science.gov (United States)

    Bracho, Carmen; Dunia, Irene; De, La Rosa Mercedes; Benedetti, Ennio-Lucio; Perez, Hilda A

    2002-03-01

    We investigated the secretory traffic of a Plasmodium vivax antigen (Pv-148) synthesised by the parasite during the blood cycle, exported into the host cell cytosol and then transported to the surface membrane of the infected erythrocyte. Studies of the ultrastructure of erythrocytes infected with P. vivax showed that intracellular schizogony is accompanied by the generation of parasite-induced membrane profiles in the erythrocyte cytoplasm. These structures are detectable soon after the parasite invades the erythrocyte and develop an elaborate organisation, leading to a tubovesicular membrane (TVM) network, in erythrocytes infected with mature trophozoites. Interestingly, the clefts formed stacked, flattened cisternae resembling a classical Golgi apparatus. The TVM network stained with the fluorescent Golgi marker Bodipy-ceramide. Specific immunolabelling showed that Pv-148 was transferred from the parasite to the erythrocyte surface membrane via the clefts and the TVM network. These findings suggest that the TVM network is part of the secretory pathways involved in parasite protein transport across the Plasmodium-infected erythrocyte and that Pv- 148 may represent a marker that links the parasite with the host cell cytoplasm and, in turn, with the extracellular milieu.

  10. Overview of Plant-Made Vaccine Antigens against Malaria

    Directory of Open Access Journals (Sweden)

    Marina Clemente

    2012-01-01

    Full Text Available This paper is an overview of vaccine antigens against malaria produced in plants. Plant-based expression systems represent an interesting production platform due to their reduced manufacturing costs and high scalability. At present, different Plasmodium antigens and expression strategies have been optimized in plants. Furthermore, malaria antigens are one of the few examples of eukaryotic proteins with vaccine value expressed in plants, making plant-derived malaria antigens an interesting model to analyze. Up to now, malaria antigen expression in plants has allowed the complete synthesis of these vaccine antigens, which have been able to induce an active immune response in mice. Therefore, plant production platforms offer wonderful prospects for improving the access to malaria vaccines.

  11. Tissue distribution of histo-blood group antigens

    DEFF Research Database (Denmark)

    Ravn, V; Dabelsteen, Erik

    2000-01-01

    carrier carbohydrate chains. Histo-blood group antigens are found in most epithelial tissues. Meanwhile, several factors influence the type, the amount, and the histological distribution of histoblood group antigens, i.e. the ABO, Lewis, and saliva-secretor type of the individual, and the cell- and tissue......The introduction of immunohistochemical techniques and monoclonal antibodies to specific carbohydrate epitopes has made it possible to study in detail the tissue distribution of histo-blood group antigens and related carbohydrate structures. The present paper summarizes the available data...... concerning the histological distribution of histo-blood group antigens and their precursor structures in normal human tissues. Studies performed have concentrated on carbohydrate antigens related to the ABO, Lewis, and TTn blood group systems, i.e. histo-blood group antigens carried by type 1, 2, and 3 chain...

  12. Nod2 is required for antigen-specific humoral responses against antigens orally delivered using a recombinant Lactobacillus vaccine platform.

    Directory of Open Access Journals (Sweden)

    Sara A Bumgardner

    Full Text Available Safe and efficacious orally-delivered mucosal vaccine platforms are desperately needed to combat the plethora of mucosally transmitted pathogens. Lactobacillus spp. have emerged as attractive candidates to meet this need and are known to activate the host innate immune response in a species- and strain-specific manner. For selected bacterial isolates and mutants, we investigated the role of key innate immune pathways required for induction of innate and subsequent adaptive immune responses. Co-culture of murine macrophages with L. gasseri (strain NCK1785, L. acidophilus (strain NCFM, or NCFM-derived mutants-NCK2025 and NCK2031-elicited an M2b-like phenotype associated with TH2 skewing and immune regulatory function. For NCFM, this M2b phenotype was dependent on expression of lipoteichoic acid and S layer proteins. Through the use of macrophage genetic knockouts, we identified Toll-like receptor 2 (TLR2, the cytosolic nucleotide-binding oligomerization domain containing 2 (NOD2 receptor, and the inflammasome-associated caspase-1 as contributors to macrophage activation, with NOD2 cooperating with caspase-1 to induce inflammasome derived interleukin (IL-1β in a pyroptosis-independent fashion. Finally, utilizing an NCFM-based mucosal vaccine platform with surface expression of human immunodeficiency virus type 1 (HIV-1 Gag or membrane proximal external region (MPER, we demonstrated that NOD2 signaling is required for antigen-specific mucosal and systemic humoral responses. We show that lactobacilli differentially utilize innate immune pathways and highlight NOD2 as a key mediator of macrophage function and antigen-specific humoral responses to a Lactobacillus acidophilus mucosal vaccine platform.

  13. Strategies to enhance immunogenicity of cDNA vaccine encoded antigens by modulation of antigen processing

    NARCIS (Netherlands)

    Platteel, Anouk C M; Marit de Groot, A; Andersen, Peter; Ovaa, Huib; Kloetzel, Peter M; Mishto, Michele; Sijts, Alice J A M

    2016-01-01

    Most vaccines are based on protective humoral responses while for intracellular pathogens CD8(+) T cells are regularly needed to provide protection. However, poor processing efficiency of antigens is often a limiting factor in CD8(+) T cell priming, hampering vaccine efficacy. The multistage cDNA

  14. Mycobacterium leprae antigens involved in human immune responses. I. Identification of four antigens by monoclonal antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Britton, W.J.; Hellqvist, L.; Basten, A.; Raison, R.L.

    1985-12-01

    Four distinct antigens were identified in soluble sonicates of Mycobacterium leprae by using a panel of 11 monoclonal antibodies. Cross-reactivity studies with other mycobacterial species were conducted by using ELISA and immunoblot assays, and demonstrated that determinants on two of the antigens were present in many mycobacteria, whereas the other two were limited in distribution. Competitive inhibition experiments with radiolabeled monoclonal antibodies showed cross-inhibition between antibodies identifying two of the four antigenicbands. These two bands, of M/sub tau/ 4.5 to 6 KD and 30 to 40 KD, were resistant to protease treatment after immunoblotting. In contrast the two other bands of 16 and 70 KD were protease-sensitive. Although all four bands reacted with some human lepromatous leprosy sera in immunoblots, the 4.5 to 6 KD and 30 to 40 KD bands were most prominent. Lepromatous leprosy sera also inhibited the binding of radiolabeled monoclonal antibodies to each of the four antigens, with the mean titer causing 50% inhibition being higher for antibodies reacting with the 4.5 to 6 KD and 30 to 40 KD bands. These findings indicated that all four antigens were involved in the human B cell response to M. leprae.

  15. Mycobacterium leprae antigens involved in human immune responses. I. Identification of four antigens by monoclonal antibodies

    International Nuclear Information System (INIS)

    Britton, W.J.; Hellqvist, L.; Basten, A.; Raison, R.L.

    1985-01-01

    Four distinct antigens were identified in soluble sonicates of Mycobacterium leprae by using a panel of 11 monoclonal antibodies. Cross-reactivity studies with other mycobacterial species were conducted by using ELISA and immunoblot assays, and demonstrated that determinants on two of the antigens were present in many mycobacteria, whereas the other two were limited in distribution. Competitive inhibition experiments with radiolabeled monoclonal antibodies showed cross-inhibition between antibodies identifying two of the four antigenicbands. These two bands, of M/sub tau/ 4.5 to 6 KD and 30 to 40 KD, were resistant to protease treatment after immunoblotting. In contrast the two other bands of 16 and 70 KD were protease-sensitive. Although all four bands reacted with some human lepromatous leprosy sera in immunoblots, the 4.5 to 6 KD and 30 to 40 KD bands were most prominent. Lepromatous leprosy sera also inhibited the binding of radiolabeled monoclonal antibodies to each of the four antigens, with the mean titer causing 50% inhibition being higher for antibodies reacting with the 4.5 to 6 KD and 30 to 40 KD bands. These findings indicated that all four antigens were involved in the human B cell response to M. leprae

  16. Manipulating the Lewis antigen specificity of the cholesterol-dependent cytolysin lectinolysin

    Directory of Open Access Journals (Sweden)

    Sara eLawrence

    2012-11-01

    Full Text Available The cholesterol-dependent cytolysins (CDCs attack cells by punching large holes in their membranes. Lectinolysin from Streptococcus mitis is unique among CDCs due to the presence of an N-terminal lectin domain that enhances the pore-forming activity of the toxin. We recently determined the crystal structures of the lectin domain in complex with various glycans. These structures revealed the molecular basis for the Lewis antigen specificity of the toxin. Based on this information we have used in silico molecular modelling to design a mutant toxin, which we predicted would increase its specificity for Lewis y, an antigen found on the surface of cancer cells. Surprisingly, we found by surface plasmon resonance binding experiments that the resultant mutant lectin domain exhibited higher specificity for Lewis b antigens instead. We then undertook comparative crystallographic and molecular dynamics simulation studies of the wild-type and mutant lectin domains to understand the molecular basis for the disparity between the theoretical and experimental results. The crystallographic results revealed that the net number of interactions between Lewis y and wild-type versus mutant was unchanged whereas there was a loss of a hydrogen bond between mutant and Lewis b compared to wild-type. In contrast, the molecular dynamics studies revealed that the Lewis b antigen spent more time in the binding pocket of the mutant compared to wild-type and the reverse was true for Lewis y. The results of these simulation studies are consistent with the conclusions drawn from the surface plasmon resonance studies. This work is part of a program to engineer lectinolysin so that it will target and kill specific cells in human diseases.

  17. Re-purification of labelled ferritin antigen with HPLC

    International Nuclear Information System (INIS)

    Zhang Haoyi; Jin Lichun

    2002-01-01

    Objective: To improve the quality of long-term stored labelled ferritin antigen with HPLC. Methods: The antigen was analyzed and purified with HPLC and again analyzed with RIA afterwards. Results: Ferritin antigen underwent significant polymerization after long-term (aggregation) storage. After re-purification with HPLC, its immuno-activity and labelled specific radioactivity were both significantly improved. Conclusion: Quality of stored ferritin RIA kit could be greatly improved after re-purification with HPLC

  18. Monoclonal antibodies to Nocardia asteroides and Nocardia brasiliensis antigens.

    OpenAIRE

    Jiménez, T; Díaz, A M; Zlotnik, H

    1990-01-01

    Nocardia asteroides and Nocardia brasiliensis whole-cell extracts were used as antigens to generate monoclonal antibodies (MAbs). Six stable hybrid cell lines secreting anti-Nocardia spp. MAbs were obtained. These were characterized by enzyme-linked immunosorbent assay, Western blot (immunoblot), and immunofluorescence assay. Although all the MAbs exhibited different degrees of cross-reactivity with N. asteroides and N. brasiliensis antigens as well as with culture-filtrate antigens from Myco...

  19. Monoclonal antibodies to carcino-embryonic antigen

    International Nuclear Information System (INIS)

    Teh, Jinghee; McKenzie, I.F.C.

    1990-01-01

    With the aim of producing new MoAb to colorectal carcinoma, immunization with cell suspensions of a fresh colonic tumour was performed and MoAb 17C4 was obtained. To produce other MoAb to colon cancer, an immunization protocol using fresh tumour, colonic cell lines and sera from patients with colonic tumours was employed and resulted in MoAb JGT-13, LK-4 and XPX-13. MoAb I-1 and O-1 were raised against sera from patients with colon cancer to produce MoAb directed against circulating tumour associated antigens. The six antibodies gave a range of reactions with normal and malignant tissues, indicating that they most likely reacted with different epitopes. Thus, apart from the reactions of 17C4, LK-4 and XPX-13 with fresh and formalin-fixed granulocytes, none of the antibodies reacted with formalin-fixed normal tissues. Despite the apparent specificity of these MoAb for colon cancer, serum testing using MoAb gave similar results to carcino-embryonic antigen polyclonal antibodies, that is the MoAb gave no obvious advantage. 9 refs., 1 tab., 3 figs

  20. Immunoregulation by Taenia crassiceps and Its Antigens

    Directory of Open Access Journals (Sweden)

    Alberto N. Peón

    2013-01-01

    Full Text Available Taenia crassiceps is a cestode parasite of rodents (in its larval stage and canids (in its adult stage that can also parasitize immunocompromised humans. We have studied the immune response elicited by this helminth and its antigens in mice and human cells, and have discovered that they have a strong capacity to induce chronic Th2-type responses that are primarily characterized by high levels of Th2 cytokines, low proliferative responses in lymphocytes, an immature and LPS-tolerogenic profile in dendritic cells, the recruitment of myeloid-derived suppressor cells and, specially, alternatively activated macrophages. We also have utilized the immunoregulatory capabilities of this helminth to successfully modulate autoimmune responses and the outcome of other infectious diseases. In the present paper, we review the work of others and ourselves with regard to the immune response induced by T. crassiceps and its antigens, and we compare the advances in our understanding of this parasitic infection model with the knowledge that has been obtained from other selected models.