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Sample records for antigen yeast-hbsag induces

  1. 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.

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

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    Adnan Ahmad

    2011-06-01

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

  3. 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.

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    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.

  4. 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....

  5. 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 ...

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

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    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

  7. Expression of Hepatitis B virus surface antigen (HBsAg from genotypes A, D and F and influence of amino acid variations related or not to genotypes on HBsAg detection

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    Natalia M. Araujo

    Full Text Available The impact of hepatitis B virus (HBV genotypes on the sensitivity of surface antigen (HBsAg detection assays has been poorly investigated. Here, plasmids carrying consensus or variant coding sequences for HBV surface proteins from genotypes A, D and F, were constructed. HBsAg levels were evaluated in medium and extracts of transfected CHO cells by a commercial polyclonal-based assay. We show that HBsAg detection values of consensus forms from genotypes D and F were, respectively, 37% and 30% lower than those obtained by genotype A. However, the presence of two single variations, T143M in genotype A, and T125M in genotype D, produced a decrease of 44% and an increase of 34%, respectively, on HBsAg mean values in comparison with their consensus forms. In conclusion, HBsAg detection levels varied among HBV genotypes. However, unique amino acid substitutions not linked to genotypes, such as T125M and T143M described here, should have more implications in HBV immunological diagnostics than the set of variations characteristic of each HBV genotype.

  8. Rational design and evaluation of HBsAg polymeric nanoparticles as antigen delivery carriers.

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    Dewangan, Hitesh Kumar; Pandey, Tarun; Maurya, Lakshmi; Singh, Sanjay

    2018-05-01

    The present work is focused on the development and evaluation of single dose sustained-release Hepatitis B surface antigen (HBsAg) loaded nanovaccine for Hepatitis B. The conventional treatment suffers from repeated administration and hence requires a booster dose. Therefore, polymeric nanovaccine of HBsAg was developed by double emulsion solvent evaporation technique, utilizing central composite design for formulation optimization. The effects of independent variables (like polymer amount, stabilizer concentration, aqueous/organic phase ratio and homogenizer speed) were also studied on critical quality attributes like particle size and entrapment efficiency. Nanovaccine was characterized in terms of physicochemical parameters, release, internalization and in vivo immunological evaluation in BALB/c mice after administration by different routes such as oral, sub-cutaneous, nasal and intramuscular. The designed nanovaccine demonstrated nanometric size with smooth surface, negative zeta potential, maximum entrapment, sustained release and better internalization in macrophage and MRC-5 cell line. The immune-stimulating activity of nanovaccine administered by different routes was evaluated by measuring anti-HBsAg titre like specific immunoglobulin IgG and IgA response and cytokine level (interleukin-2, interferon-Y) measurement. The results indicated that the nanovaccine administered by intramuscular route produced better humoral as well as cellular responses and potential carriers for antigen delivery at single dose administration via intramuscular route. Copyright © 2018 Elsevier B.V. All rights reserved.

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

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    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.

  10. Application of a Newly Developed High-Sensitivity HBsAg Chemiluminescent Enzyme Immunoassay for Hepatitis B Patients with HBsAg Seroclearance

    OpenAIRE

    Shinkai, Noboru; Matsuura, Kentaro; Sugauchi, Fuminaka; Watanabe, Tsunamasa; Murakami, Shuko; Iio, Etsuko; Ogawa, Shintaro; Nojiri, Shunsuke; Joh, Takashi; Tanaka, Yasuhito

    2013-01-01

    We modified and automated a highly sensitive chemiluminescent enzyme immunoassay (CLEIA) for surface antigen (HBsAg) detection using a combination of monoclonal antibodies, each for a specific epitope of HBsAg, and by improving an earlier conjugation technique. Of 471 hepatitis B virus (HBV) carriers seen in our hospital between 2009 and 2012, 26 were HBsAg seronegative as determined by the Abbott Architect assay. The Lumipulse HBsAg-HQ assay was used to recheck those 26 patients who demonstr...

  11. Antigenic characterisation of yeast-expressed lyssavirus nucleoproteins.

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    Kucinskaite, Indre; Juozapaitis, Mindaugas; Serva, Andrius; Zvirbliene, Aurelija; Johnson, Nicholas; Staniulis, Juozas; Fooks, Anthony R; Müller, Thomas; Sasnauskas, Kestutis; Ulrich, Rainer G

    2007-12-01

    In Europe, three genotypes of the genus Lyssavirus, family Rhabdoviridae, are present, classical rabies virus (RABV, genotype 1), European bat lyssavirus type 1 (EBLV-1, genotype 5) and European bat lyssavirus type 2 (EBLV-2, genotype 6). The entire authentic nucleoprotein (N protein) encoding sequences of RABV (challenge virus standard, CVS, strain), EBLV-1 and EBLV-2 were expressed in yeast Saccharomyces cerevisiae at high level. Purification of recombinant N proteins by caesium chloride gradient centrifugation resulted in yields between 14-17, 25-29 and 18-20 mg/l of induced yeast culture for RABV-CVS, EBLV-1 and EBLV-2, respectively. The purified N proteins were evaluated by negative staining electron microscopy, which revealed the formation of nucleocapsid-like structures. The antigenic conformation of the N proteins was investigated for their reactivity with monoclonal antibodies (mAbs) directed against different lyssaviruses. The reactivity pattern of each mAb was virtually identical between immunofluorescence assay with virus-infected cells, and ELISA and dot blot assay using the corresponding recombinant N proteins. These observations lead us to conclude that yeast-expressed lyssavirus N proteins share antigenic properties with naturally expressed virus protein. These recombinant proteins have the potential for use as components of serological assays for lyssaviruses.

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

    Science.gov (United States)

    2012-01-01

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

  13. Application of a newly developed high-sensitivity HBsAg chemiluminescent enzyme immunoassay for hepatitis B patients with HBsAg seroclearance.

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    Shinkai, Noboru; Matsuura, Kentaro; Sugauchi, Fuminaka; Watanabe, Tsunamasa; Murakami, Shuko; Iio, Etsuko; Ogawa, Shintaro; Nojiri, Shunsuke; Joh, Takashi; Tanaka, Yasuhito

    2013-11-01

    We modified and automated a highly sensitive chemiluminescent enzyme immunoassay (CLEIA) for surface antigen (HBsAg) detection using a combination of monoclonal antibodies, each for a specific epitope of HBsAg, and by improving an earlier conjugation technique. Of 471 hepatitis B virus (HBV) carriers seen in our hospital between 2009 and 2012, 26 were HBsAg seronegative as determined by the Abbott Architect assay. The Lumipulse HBsAg-HQ assay was used to recheck those 26 patients who demonstrated seroclearance by the Abbott Architect assay. The performance of the Lumipulse HBsAg-HQ assay was compared with that of a quantitative HBsAg detection system (Abbott Architect) and the Roche Cobas TaqMan HBV DNA assay (CTM) (lower limit of detection, 2.1 log copies/ml) using blood serum samples from patients who were determined to be HBsAg seronegative by the Abbott Architect assay. Ten patients had spontaneous HBsAg loss. Of 8 patients treated with nucleotide analogues (NAs), two were HBsAg seronegative after stopping lamivudine therapy and 6 were HBsAg seronegative during entecavir therapy. Eight acute hepatitis B (AH) patients became HBsAg seronegative. Of the 26 patients, 16 were HBsAg positive by the Lumipulse HBsAg-HQ assay but negative by the Abbott Architect assay. The differences between the two assays in terms of detectable HBsAg persisted over the long term in the spontaneous loss group (median, 10 months), the NA-treated group (2.5 months), and the AH group (0.5 months). In 9 patients, the Lumipulse HBsAg-HQ assay detected HBsAg when HBV DNA was negative by the CTM assay. HBsAg was also detected by the Lumipulse HBsAg-HQ assay in 4 patients with an anti-HBs concentration of >10 mIU/ml, 3 of whom had no HBsAg escape mutations. The automatic, highly sensitive HBsAg CLEIA Lumipulse HBsAg-HQ is a convenient and precise assay for HBV monitoring.

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

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    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.

  15. Comparison of serum HBsAg quantitation by four immunoassays, and relationships of HBsAg level with HBV replication and HBV genotypes.

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    Edouard Tuaillon

    Full Text Available BACKGROUND: The decline in hepatitis B virus surface antigen (HBsAg may be an early predictor of the viral efficacy of Hepatitis B virus (HBV therapy. The HBsAg levels obtained by different immunoassays now need comparing and the relationships between levels of HBsAg and HBV DNA alongside HBsAg and genotype must be evaluated. METHODOLOGY/PRINCIPAL FINDINGS: HBsAg levels were compared among 80 patients using the Abbott Architect assay, a commercial immunoassay approved for HBsAg detection and quantitation, and three other assays derived from immunoassays approved for HBsAg detection (manufactured by Diasorin, Bio-Rad and Roche. Good correlation was found between the Abbot vs. Diasorin, Bio-Rad and Roche assays with narrow 95% limits of agreement and small mean differences: -0.06 to 0.11, -0.09 log(10 IU/mL; -0.57 to 0.64, -0.04 log(10 IU/mL; -0.09 to 0.45, -0.27 log(10 IU/mL, respectively. These agreements were not affected by genotypes A or D. HBsAg was weakly correlated with HBV DNA, whatever the HBsAg assay used: Abbott, ρ = 0.36 p = 0.001, Diasorin ρ = 0.34, p = 0.002; Bio-Rad ρ = 0.37, p<0.001; or Roche ρ = 0.41, p<0.001. This relationship between levels of HBsAg and HBV DNA seemed to depend on genotypes. Whereas HBsAg (Abbott assay tended to correlate with HBV DNA for genotype A (ρ = 0.44, p = 0.02, no such correlation was significant for genotypes D (ρ = 0.29, p = 0.15. CONCLUSION/SIGNIFICANCE: The quantitation of HBsAg in routine clinical samples is comparable between the reference assay and the adapted assays with acceptable accuracy limits, low levels of variability and minimum discrepancy. While HBsAg quantitation is not affected by HBV genotype, the observed association between levels of HBsAg and HBV DNA seems genotype dependent.

  16. [Clinical evaluation of a novel HBsAg quantitative assay].

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    Takagi, Kazumi; Tanaka, Yasuhito; Naganuma, Hatsue; Hiramatsu, Kumiko; Iida, Takayasu; Takasaka, Yoshimitsu; Mizokami, Masashi

    2007-07-01

    The clinical implication of the hepatitis B surface antigen (HBsAg) concentrations in HBV-infected individuals remains unclear. The aim of this study was to evaluate a novel fully automated Chemiluminescence Enzyme Immunoassay (Sysmex HBsAg quantitative assay) by comparative measurements of the reference serum samples versus two independent commercial assays (Lumipulse f or Architect HBsAg QT). Furthermore, clinical usefulness was assessed for monitoring of the serum HBsAg levels during antiviral therapy. A dilution test using 5 reference-serum samples showed linear correlation curve in range from 0.03 to 2,360 IU/ml. The HBsAg was measured in total of 400 serum samples and 99.8% had consistent results between Sysmex and Lumipulse f. Additionally, a positive linear correlation was observed between Sysmex and Architect. To compare the Architect and Sysmex, both methods were applied to quantify the HBsAg in serum samples with different HBV genotypes/subgenotypes, as well as in serum contained HBV vaccine escape mutants (126S, 145R). Correlation between the methods was observed in results for escape mutants and common genotypes (A, B, C) in Japan. Observed during lamivudine therapy, an increase in HBsAg and HBV DNA concentrations preceded the aminotransferase (ALT) elevation associated with drug-resistant HBV variant emergence (breakthrough hepatitis). In conclusion, reliability of the Sysmex HBsAg quantitative assay was confirmed for all HBV genetic variants common in Japan. Monitoring of serum HBsAg concentrations in addition to HBV DNA quantification, is helpful in evaluation of the response to lamivudine treatment and diagnosis of the breakthrough hepatitis.

  17. Poly-ϵ-caprolactone/chitosan nanoparticles provide strong adjuvant effect for hepatitis B antigen.

    Science.gov (United States)

    Jesus, Sandra; Soares, Edna; Borchard, Gerrit; Borges, Olga

    2017-10-01

    This work aims to investigate the adjuvant effect of poly-ϵ-caprolactone/chitosan nanoparticles (NPs) for hepatitis B surface antigen (HBsAg) and the plasmid DNA encoding HBsAg (pRC/CMV-HBs). Both antigens were adsorbed onto preformed NPs. Vaccination studies were performed in C57BL/6 mice. Transfection efficiency was investigated in A549 cell line. HBsAg-adsorbed NPs generated strong anti-HBsAg IgG titers, mainly of IgG1 isotype, and induced antigen-specific IFN-γ and IL-17 secretion by spleen cells. The addition of pRC/CMV-HBs to the HBsAg-adsorbed NPs inhibited IL-17 secretion but had minor effect on IFN-γ levels. Lastly, pRC/CMV-HBs-loaded NPs generated a weak serum antibody response. Poly-ϵ-caprolactone/chitosan NPs provide a strong humoral adjuvant effect for HBsAg and induce a Th1/Th17-mediated cellular immune responses worth explore for hepatitis B virus vaccination.

  18. Comparative study of methods of detection of hepatitis ′B′ surface antigen (HBsAg.

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    Parab V

    1989-04-01

    Full Text Available The serum samples were collected from 52 patients of acute viral hepatitis and 235 hospital staff from Kasturba Hospital for Infectious Diseases. HBsAg was detected in their sera by counter-immuno-electrophoresis (CIEP, reverse passive hemogglutination (RPHA and by micro-enzyme-linked-immunosorbent assay (ELISA technique. Among the patients, HBsAg was detected in 12 cases (23% by CIEP, in 18 cases (34% by RPHA and in 23 patients (45% by ELISA. In the hospital staff, HBsAg was detected in 4 samples (1.7% by CIEP, in 8 samples (3.5% by RPHA and in 32 samples (13.5% by ELISA. Thus ELISA was found to be the most sensitive technique in detecting HBsAg.

  19. An observation on positive rate of HBsAg in the urine of patients suffering from positive serum HBsAg

    Energy Technology Data Exchange (ETDEWEB)

    Peixun, Lin; Mingzheng, Zeng; Xiaoling, Chai [Wuhan Eighth Municipal Hospital, HB (China). Dept. of Laboratory

    1989-08-01

    In 1983, the Virus Research Office of the Shanxi Research Insitute of Preventive Medicine found out the granules of hepatitis B virus from the urine of patients and proved that this kind of virus can be spread through the urine. With the help of self-developed method of radio immunoelectrophoresis, our research office has purified and concentrated the urine of the patients suffering from positive serum HBsAg (hepatitis B surface antigen). Among them 25 are male, and another 25 are female. The result shows that the positive rate of HBsAg accounts for 80%. This is of important significance to the care of urine specimens, the protection of experimentalists and the development of clinical medicine.

  20. Strong and multi-antigen specific immunity by hepatitis B core antigen (HBcAg)-based vaccines in a murine model of chronic hepatitis B: HBcAg is a candidate for a therapeutic vaccine against hepatitis B virus.

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    Akbar, Sheikh Mohammad Fazle; Chen, Shiyi; Al-Mahtab, Mamun; Abe, Masanori; Hiasa, Yoichi; Onji, Morikazu

    2012-10-01

    Experimental evidence suggests that hepatitis B core antigen (HBcAg)-specific cytotoxic T lymphocytes (CTL) are essential for the control of hepatitis B virus (HBV) replication and prevention of liver damage in patients with chronic hepatitis B (CHB). However, most immune therapeutic approaches in CHB patients have been accomplished with hepatitis B surface antigen (HBsAg)-based prophylactic vaccines with unsatisfactory clinical outcomes. In this study, we prepared HBsAg-pulsed dendritic cells (DC) and HBcAg-pulsed DC by culturing spleen DC from HBV transgenic mice (HBV TM) and evaluated the immunomodulatory capabilities of these antigens, which may serve as a better therapy for CHB. The kinetics of HBsAg, antibody levels against HBsAg (anti-HBs), proliferation of HBsAg- and HBcAg-specific lymphocytes, production of antigen-specific CTL, and activation of endogenous DC were compared between HBV TM vaccinated with either HBsAg- or HBcAg-pulsed DC. Vaccination with HBsAg-pulsed DC induced HBsAg-specific immunity, but failed to induce HBcAg-specific immunity in HBV TM. However, immunization of HBV TM with HBcAg-pulsed DC resulted in: (1) HBsAg negativity, (2) production of anti-HBs, and (3) development of HBsAg- and HBcAg-specific T cells and CTL in the spleen and the liver. Additionally, significantly higher levels of activated endogenous DC were detected in HBV TM immunized with HBcAg-pulsed DC compared to HBsAg-pulsed DC (pdamage suggests that HBcAg should be an integral component of the therapeutic vaccine against CHB. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. 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.

  2. Spontaneous HBsAg loss in Korean patients: relevance of viral genotypes, S gene mutations, and covalently closed circular DNA copy numbers

    Directory of Open Access Journals (Sweden)

    Kyun-Hwan Kim

    2014-09-01

    Full Text Available Background/AimsOccult HBV infection can persist following HBsAg loss and be transmitted, but the virological features are not well defined.MethodsHere we investigated 25 Korean patients who lost HBsAg during follow up, either spontaneously or subsequent to therapy.ResultsWhereas subtype adr (genotype C was found in 96% of HBsAg positive patients, 75 % of patients who lost HBsAg spontaneously were seemed to be infected with the ayw subtype with sequence similar to genotype D. Mutations in the major hydrophilic region (MHR of HBsAg were found in 7 patients who lost HBsAg spontaneously. The mutations include T123S, M125I/N, C139R, D144E, V177A, L192F, and W196L, some of which have not been reported before. Functional analysis via transfection experiments indicate that the C139R and D144E mutations drastically reduced HBsAg antigenicity, while the Y225del mutation found in one interferon-treated patient impaired HBsAg secretion.ConclusionsLack of detectable HBsAg in patient serum could be explained by low level of ccc DNA in liver tissue, low antigenicity of the surface protein, or its secretion defect.

  3. 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.)

  4. Reactivation of hepatitis B virus infection with persistently negative HBsAg on three HBsAg assays in a lymphoma patient undergoing chemotherapy.

    Science.gov (United States)

    Cheung, Wing-I; Chan, Henry Lik-Yuen; Leung, Vincent King-Sun; Tse, Chi-Hang; Fung, Kitty; Lin, Shek-Ying; Wong, Ann; Wong, Vincent Wai-Sun; Chau, Tai-Nin

    2010-02-01

    In patients with occult hepatitis B virus (HBV) infection, acute exacerbation may occur when they become immunocompromised. Usually, these patients develop hepatitis B surface antigen (HBsAg) seroreversion during the flare. Here we report on a patient with occult HBV infection, who developed HBV exacerbation after chemotherapy for diffuse large B-cell lymphoma. The resurgence of HBV DNA preceded the elevation of liver enzymes for 20 weeks. Atypically, despite high viraemia, serological tests showed persistently negative HBsAg using three different sensitive HBsAg assays (i.e., Architect, Murex and AxSYM). On comparing the amino acid sequence of the index patient with the consensus sequence, five mutations were found at pre-S1, five at pre-S2 and twenty-three mutations at the S region. Six amino acid mutations were located in the 'a' determinant, including P120T, K122R, M133T, F134L, D144A and G145A. The mutants K122R, F134L and G145A in our patient have not been tested for their sensitivity to Architect and Murex assays by the previous investigators and might represent the escape mutants to these assays.

  5. Posintro™-HBsAg, a modified ISCOM including HBsAg, induces strong cellular and humoral responses

    DEFF Research Database (Denmark)

    Schiött, Asa; Larsson, Kristina; Manniche, Søren

    2011-01-01

    HBsAg vaccine formulation, Posintro™-HBsAg, was compared to two commercial hepatitis B vaccines including aluminium or monophosphoryl lipid A (MPL) and the two adjuvant systems MF59 and QS21 in their efficiency to prime both cellular and humoral immune responses. The Posintro™-HBsAg induced...

  6. Membranous glomerulonephritis in a child asymptomatic for hepatitis B virus. Concomitant seropositivity for HBsAG and anti-HBs.

    Science.gov (United States)

    Hirsch, H Z; Ainsworth, S K; DeBeukelaer, M; Brissie, R M; Hennigar, G R

    1981-04-01

    The presence of hepatitis B surface antigen (HBsAg) in association with immunoglobulins and complement components within the glomerular basement membranes of adults having chronic active hepatitis has been well documented. In addition, investigators in Poland have demonstrated HBsAg immune complexes in glomeruli of children who did not have clinical evidence of hepatitis. More recently, a single case of childhood membranous glomerulonephritis in an asymptomatic carrier of hepatitis B virus was cited by observers in Canada. Reported here is the deposition of HBsAg immune complexes in the glomerular basement membranes of a 13-year-old black boy who had membranous glomerulopathy but not clinical evidence of hepatitis. This may be the first reported case in the United States of HbsAg-associated membranous glomerulonephritis in a child asymptomatic for hepatitis B virus, and only the second such case in North America. However, unlike previous studies of childhood glomerulopathy in association with hepatitis B virus, this patient is seropositive for both HBsAg and anti-HBs (antibody for hepatitis B surface antigen). Similar "rare" serologic findings were found for the patient's eldest male sib.

  7. 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).

  8. Seroprevalence of HDV infection in HBsAg positive population in Ismailia, Egypt.

    Science.gov (United States)

    Gomaa, Nahed I M; Metwally, Lobna A; Nemr, Nader; Younis, Soha

    2013-01-01

    Hepatitis D virus (HDV) is a defective RNA virus that needs hepatitis B surface antigen (HBsAg) from HBV for transmission. HDV can lead to fulminant hepatitis and the progression of chronic liver damage in patients with chronic hepatitis B. The aim of this study was to determine the seroprevalence of HDV among HBsAg positive individuals in Ismailia, Egypt. Serum samples were collected from 170 HBsAg positive healthy individuals from Suez Canal University blood bank over a one year period. All of them were seeking blood donation and found to be HBsAg positive during viral hepatitis screening workups which is routinely done prior to donation. Serum samples were screened for IgG antibodies to hepatitis delta virus (HDV) using enzyme-linked immunosorbent assay (ELISA) method. Anti-HDV antibodies were detected in 8 (4.7%) individuals aged from 29-43 years. Liver function tests showed that serum ALT and AST levels were elevated in the HBsAglanti-HDV positive cases. It is concluded that the rate of HDV infection in Ismailia is high and further investigation is needed to validate the findings and raise awareness about the risk of dual HBV and HDV infection.

  9. 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

  10. No response to hepatitis B vaccine in infants born to HBsAg(+) mothers is associated to the transplacental transfer of HBsAg.

    Science.gov (United States)

    Wang, Jing; He, Yingli; Jin, Dongfang; Liu, Jinfeng; Zheng, Jie; Yuan, Ningxia; Bai, Yun; Yan, Taotao; Yang, Yuan; Liu, Yong; Zhang, Shulin; Zhao, Yingren; Chen, Tianyan

    2017-08-01

    No or low hepatitis B (HB) vaccine response is more frequent in infants from HBsAg(+) mothers than those from HBsAg(-). Our previous study found temporary positivity of HBsAg in infants from HBsAg(+) mothers. In this study, we hypothesized that HBsAg in infant blunt immune response to standard hepatitis B vaccination. A total of 328 consecutive HBsAg(+) mothers and their offspring were enrolled. Blood samples were taken from mothers and their infants and quantified for HBsAg, anti-HBs titer and HBV DNA load concentration; Placenta samples were collected to stain for HBsAg. First, 6.7% infants (22/328) showed anti-HBs titer lower than 10 mIU/mL after HB vaccination (non-response to HB vaccine). HBsAg(+) newborns showed higher risk of non-response than HBsAg(-) infants (13.0% versus 5.0%, p = 0.016). Infants from high HBsAg titer mothers displayed higher risk of HBsAg positivity at birth than those from low titer mothers (45.3% versus 2.8%, p < 0.001). HBsAg titer in mothers of HBsAg(+) newborns was much higher than mothers of HBsAg(-) newborns (p < 0.001). All those data supported HBsAg can be transferred through placenta. Our hypothesis was further reinforced by immunostaining with specific antibody against HBsAg, a substantial higher prevalence (87.5% versus 30.8%, p = 0.024) and stronger immunostaining (p = 0.008) was demonstrated in HBsAg(+) group comparing with placenta of the HBsAg(-) group. No response to HB vaccine in infants of HBsAg(+) mothers was associated to the transplacental transfer of HBsAg.

  11. Construction and immunological evaluation of truncated hepatitis B core particles carrying HBsAg amino acids 119–152 in the major immunodominant region (MIR)

    Energy Technology Data Exchange (ETDEWEB)

    Su, Qiudong; Yi, Yao [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing 102206 (China); Guo, Minzhuo [Beijing Entry-Exit Inspection and Quarantine Beureau, Tianshuiyuan Lane 6, Chaoyang District, Beijing 100026 (China); Qiu, Feng; Jia, Zhiyuan; Lu, Xuexin; Meng, Qingling [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing 102206 (China); Bi, Shengli, E-mail: shengli_bi@163.com [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing 102206 (China)

    2013-09-13

    Highlights: •The conformational HBV neutralization antigen domain was successfully displayed on the surface of truncated HBc particles. •Appropriate dialysis procedures to support the renaturing environment for the protein refolding. •Efficient purification procedures to obtain high purity and icosahedral particles of mosaic HBV antigen. •Strong immune responses not only including neutralization antibody response but also Th1 cell response were induced in mice. -- Abstract: Hepatitis B capsid protein expressed in Escherichia coli can reassemble into icosahedral particles, which could strongly enhance the immunogenicity of foreign epitopes, especially those inserted into its major immunodominant region. Herein, we inserted the entire ‘α’ antigenic determinant amino acids (aa) 119–152 of HBsAg into the truncated HBc (aa 1–144), between Asp{sup 78} and Pro{sup 79}. Prokaryotic expression showed that the mosaic HBc was mainly in the form of inclusion bodies. After denaturation with urea, it was dialyzed progressively for protein renaturation. We observed that before and after renaturation, mosaic HBc was antigenic as determined by HBsAg ELISA and a lot of viruslike particles were observed after renaturation. Thus, we further purified the mosaic viruslike particles by (NH{sub 4}){sub 2}SO{sub 4} precipitation, DEAE chromatography, and Sepharose 4FF chromatography. Negative staining electron microscopy demonstrated the morphology of the viruslike particles. Immunization of Balb/c mice with mosaic particles induced the production of anti-HBs antibody and Th1 cell immune response supported by ELISPOT and CD4/CD8 proportions assay. In conclusion, we constructed mosaic hepatitis core particles displaying the entire ‘α’ antigenic determinant on the surface and laid a foundation for researching therapeutic hepatits B vaccines.

  12. 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.

  13. The impact of maternal HBsAg carrier status on pregnancy outcomes: a case-control study.

    Science.gov (United States)

    Tse, Ka Yu; Ho, Lai Fong; Lao, Terence

    2005-11-01

    To examine the impact of maternal HBsAg carrier status on pregnancy outcomes. Two hundred and fifty-three carriers of hepatitis B surface antigen (HBsAg) with singleton pregnancy, were retrospectively compared with 253 controls matched for age and parity and year of delivery. On univariable analysis, HBsAg carriers had higher incidences of threatened preterm labour at <37 weeks (11.9% vs. 6.3%, P=0.030), preterm birth at <34 weeks (4.7% vs. 1.2%, P=0.033), gestational diabetes mellitus (19.0% vs. 11.1%, P=0.012) and antepartum haemorrhage (11.5% vs. 5.5%, P=0.026). Their infants had lower Apgar scores at the 1st (8.47+/-1.67 vs. 8.87+/-1.07, P=0.001) and 5th minute (9.56+/-1.29 vs. 9.80+/-0.54, P=0.007), and increased incidence of intraventricular haemorrhage (4.7% vs. 0.8%, P=0.007). On multivariable analysis, the association between HBsAg carrier state with antepartum haemorrhage, gestational diabetes mellitus and threatened preterm labour were confirmed. HBsAg carriers have increased risk of gestational diabetes mellitus, antepartum haemorrhage, and threatened preterm labour. This may be related to the chronic inflammatory state in these subjects. The role of chronic HBV infection in pregnancy complications has to be further elucidated.

  14. Purification of HBsAg produced by the human hepatoma cell line PLC/PRE/5 by affinity chromatography using monoclonal antibodies and application for ELISA diagnostic.

    Science.gov (United States)

    Merten, O W; Reiter, S; Scheirer, W; Katinger, H

    1983-01-01

    The human cell line PLC/PRF/5 (5) was used for the production of hepatitis B surface antigen subtype ad (HBsAg ad) and purified by affinity chromatography (AC) with monoclonal antibodies (mAb). mAb to HBsAg from mouse ascites have been purified by Protein A - AC prior coupling to AH-Sepharose 4B (Pharmacia). The combined procedure of ammonium-sulphate-precipitation of HBsAg from culture supernatants and immunosorbent-AC leads to approx. 700-fold purification. ELISA results using the mAb and the HBsAg for diagnostics of human serum, positive for anti-HBsAg-antibodies correlate with the RIA (AUSAB, Abbott).

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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 ...

  20. Viral hepatitis and rapid diagnostic test based screening for HBsAg in HIV-infected patients in rural Tanzania.

    Directory of Open Access Journals (Sweden)

    Fabian C Franzeck

    Full Text Available BACKGROUND: Co-infection with hepatitis B virus (HBV is highly prevalent in people living with HIV in Sub-Saharan Africa. Screening for HBV surface antigen (HBsAg before initiation of combination antiretroviral therapy (cART is recommended. However, it is not part of diagnostic routines in HIV programs in many resource-limited countries although patients could benefit from optimized antiretroviral therapy covering both infections. Screening could be facilitated by rapid diagnostic tests for HBsAg. Operating experience with these point of care devices in HIV-positive patients in Sub-Saharan Africa is largely lacking. We determined the prevalence of HBV and Hepatitis C virus (HCV infection as well as the diagnostic accuracy of the rapid test device Determine HBsAg in an HIV cohort in rural Tanzania. METHODS: Prospectively collected blood samples from adult, HIV-1 positive and antiretroviral treatment-naïve patients in the Kilombero and Ulanga antiretroviral cohort (KIULARCO in rural Tanzania were analyzed at the point of care with Determine HBsAg, a reference HBsAg EIA and an anti-HCV EIA. RESULTS: Samples of 272 patients were included. Median age was 38 years (interquartile range [IQR] 32-47, 169/272 (63% subjects were females and median CD4+ count was 250 cells/µL (IQR 97-439. HBsAg was detected in 25/272 (9.2%, 95% confidence interval [CI] 6.2-13.0% subjects. Of these, 7/25 (28% were positive for HBeAg. Sensitivity of Determine HBsAg was rated at 96% (95% CI 82.8-99.6% and specificity at 100% (95% CI, 98.9-100%. Antibodies to HCV (anti-HCV were found in 10/272 (3.7%, 95% CI 2.0-6.4% of patients. CONCLUSION: This study reports a high prevalence of HBV in HIV-positive patients in a rural Tanzanian setting. The rapid diagnostic test Determine HBsAg is an accurate assay for screening for HBsAg in HIV-1 infected patients at the point of care and may further help to guide cART in Sub-Saharan Africa.

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

    Directory of Open Access Journals (Sweden)

    Xiao-Xian Cui

    2017-12-01

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

  2. Importance of radioimmunoassays (HBsAg, HBsAb and HBcAb) for reducing the risk of hepatitis B transfer by blood

    International Nuclear Information System (INIS)

    Novak, J.; Kselikova, M.

    1979-01-01

    The principles are reported of the radioimmunoanalytical assay of the hepatitis B surface antigen, antibodies against this antigen which constitute immunologically indirect evidence, and antibodies against the nucleus of Dane's particles, which is circumstantial immunological evidence. The results obtained by radioimmunoassay are compared with those obtained by enzyme immunoassay. The results are presented obtained during the investigations of a total of 79 individuals, blood donors, health workers, and haemodialytic patients. In the whole group the hepatitis B surface antigen was proved by radioimmunoassay in 54%, by enzyme immunoassay in 47%; the antibody against the hepatitis B surface antigen in 19%; the antibody against the nucleus of the hepatitis B virus showed the largest proportion 75%. In 6.3% radioimmunoassay showed symptoms all three of hepatitis B, i.e., the surface antigen, the antibody against it, and the antibody against the hepatitis B virus nucleus; the correlation of the three symptoms is shown. The presence of HBsAg, HBsAb, and HBcAb is believed to be a contraindication of blood taking for routine purposes; the disappearance of HBsAg for a longer time may justify the re-inclusion among blood donors; the presence of HBsAb and HBcAb does not preclude the preparation of the plasma from such blood for the production of a specific anti-HBs immunoglobulin. (author)

  3. 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

  4. 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.

  5. Liver cancer: expression features of hepatitis B antigens

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    V. A. Tumanskiy

    2013-12-01

    Full Text Available Introduction. Hepatocellular carcinoma (HCC is currently the fifth most common malignancy in men and the eighth in women worldwide. According to the latest European Union countries’ statistics the incidence of HC cancer is about 8,29 per 100000 accidents, cholangiocellular (CC cancer – 0,9-1,3 per 100 thousand of population per year[10,14]. Hepatitis B virus (HBV is the major etiologic factor for the development of HCC [18]. People chronically infected with HBV are 20 times more likely to develop liver cancer than uninfected people [1,22,28]. Many studies have shown the association between Hepatitis B virus (HBV and hepatitis C virus (HCV infections and the development of cholangiocarcinoma (CCA [4,6,9,11,12]. At the same time, the expression features of HBsAg, HBcAg in HCC and CCA have not been studied clearly yet. Aim of investigation: to study the expression features of hepatitis B antigens in tumor tissue from patients with hepatocellular carcinoma and cholangiocarcinoma. Materials and methods. The complex pathomorphological research was performed using liver biopsies of 87 patients aged from 33 up to 83 years, where 50 (57,47% of them had HCC carcinoma and 37 (42,53% had cholangiocellular cancer. 15 patients among examined 87 ones were ill with chronic viral hepatitis (11 were ill with HCV, 3 – HBV B, 1 – HBV + HCV before, 72 cancer patients, corresponding to the clinical data, never had this one in their past medical history. The localization of hepatitis B surface antigen (HBsAg and core antigen (HBcAg was investigated by an indirect immunoperoxidase method in formalin-fixed, paraffin-embedded liver specimens obtained from 50 (57,47% patients with hepatocellular carcinoma and 37 (42,53% patients with cholangiocarcinoma. using antibodies Rb a-Hu Primary Hepatitis B Virus Core Antigen (HBcAg and Mo a-Hu Primary Hepatitis B Virus Surface Antigen (HBsAg, Сlone 3E7, and visualization system DAKO EnVision+ with diaminobenzidine. Liver

  6. 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

  7. Detection of hepatitis B virus infection in HBsAg-negative patients by monoclonal antibodies against HBsAg

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Y K

    1986-11-01

    The technique of producing antibody secreting hybridomas has made available high-affinity antibodies of predefined specificity for use as diagnostic reagents. Recently, high-affinity monoclonal antibodies to hepatitis B surface antigens (HBsAg) were produced and characterized. Immunoassay was developed using these antibodies for the detection of HBsAg-associated determinants. The present study indicated the significance of the enhanced detection by monoclonal radioimmunoassay (M-RIA) of HBsAg in sera of patients with hepatitis B virus infection. The M-RIA detected HBsAg in sera of hemodialysis patients and blood donor defined as HBsAg-negative by polyclonal RIA (2.2 %, 0.14 %, respectively). Furthermore, individuals with chronic liver diseases were reactive only in the M-RIA (chronic hepatitis 4.8 %, liver cirrhosis 10.0 %, hepatocellular carcinoma 22.2 %). It is noteworthy that some of these patients were diagnosesed as so-called non-A non-B hepatitis because of no serological markers of hepatitis B virus infection such as HBsAb and HBcAb. The enhanced performance of the monoclonal RIA compared to conventional RIA was due to the increased sensitivity of the assay (55 pg vs 230 pg/ml). In immunohistochemical study, one of the monoclonal antibody named 5C3 was applied for detection of HBsAg in the formalin-fixed paraffin-embedded liver. HBsAg was detected in 6 out of 41 HBsAg-seronegative liver specimen. Thus, the studies showed the importance of the clinical application of monoclonal antibodies such as immunoassay and immunohistochemical study in the diagnosis of hepatitis B virus infection.

  8. Detection of hepatitis B virus infection in HBsAg-negative patients by monoclonal antibodies against HBsAg

    International Nuclear Information System (INIS)

    Fujita, Y.K.

    1986-01-01

    The technique of producing antibody secreting hybridomas has made available high-affinity antibodies of predefined specificity for use as diagnostic reagents. Recently, high-affinity monoclonal antibodies to hepatitis B surface antigens (HBsAg) were produced and characterized. Immunoassay was developed using these antibodies for the detection of HBsAg-associated determinants. The present study indicated the significance of the enhanced detection by monoclonal radioimmunoassay (M-RIA) of HBsAg in sera of patients with hepatitis B virus infection. The M-RIA detected HBsAg in sera of hemodialysis patients and blood donor defined as HBsAg-negative by polyclonal RIA (2.2 %, 0.14 %, respectively). Furthermore, individuals with chronic liver diseases were reactive only in the M-RIA (chronic hepatitis 4.8 %, liver cirrhosis 10.0 %, hepatocellular carcinoma 22.2 %). It is noteworthy that some of these patients were diagnosesed as so-called non-A non-B hepatitis because of no serological markers of hepatitis B virus infection such as HBsAb and HBcAb. The enhanced performance of the monoclonal RIA compared to conventional RIA was due to the increased sensitivity of the assay (55 pg vs 230 pg/ml). In immunohistochemical study, one of the monoclonal antibody named 5C3 was applied for detection of HBsAg in the formalin-fixed paraffin-embedded liver. HBsAg was detected in 6 out of 41 HBsAg-seronegative liver specimen. Thus, the studies showed the importance of the clinical application of monoclonal antibodies such as immunoassay and immunohistochemical study in the diagnosis of hepatitis B virus infection. (author)

  9. HBsAg d and y subtypes determined by inhibition radio-immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, R [Border Blood Transfusion Service, East London (South Africa)

    1981-12-01

    An inhibition radioimmunoassay for the detection of HBsAg/d and HBsAg/y antigens is described. A survey of 211 asymptomatic HBsAg positive blood donors showed 190 to be of type HBsAg/d and 3 to be of type HBsAg/y, while the remaining 18 could not be typed. Of 43 patients with acute hepatitis 39 were type HBsAg/d and 4 were type HBsAg/y. The statistically significant (p smaller than 0,01) increase in type HBsAg/y may reflect a changing pattern in offending viral strain with the passage of time.

  10. 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

  11. Detection of S-gene 'a' determinant variants in hepatitis B patients with both positive HBsAg and HBsAb markers

    International Nuclear Information System (INIS)

    Wu Yueping; Ling Yongwu; Huang Songping; Wang Shipeng; Chen Yufeng; Mao Liping; Lu Jianrong

    2005-01-01

    Objective: To explore the S-gene 'a' determinant variants in hepatitis B patients with both positive HBsAg and HBsAb markers and the effect on the antigenicity of HBsAg. Methods: Quantitative determination of HBV - DNA with competent PCR microfluidic chit method was performed in eight sera specimens from seven hepatitis B patients with both positive HBsAg and HBsAb markers. HBV S-gene was amplified with nested PCR, the PCR product was directly examined for any sequence variant of the amino acids. HBV markers were tested with the very sensitive ELISA/MEIA method in these seven patients. The above rests were also performed in 15 children after failed immunization with hepatitis B vaccine and 9 recipients of liver transplantation for terminal hepatitis B treated with HBIG and lamivudine, serving as controls. Results: The HBsAb contents in the seven patients were all below 80 mIu/ml. Two of the patients with positive HBV-DNA showed no 'a' determinant variant. Two of the four HBV-DNA negative patients demonstrated amino-acid variants (126, 131). One patients who was originally HBV-DNA positive but later turned negative after treatment with interferon and lamivudine demonstrated variant (126). In the 9 patients after successful liver transplantation, the HBsAb contents were all about 150mIu/ml with negative HBV-DNA and no variant. In the 15 immunization failures, HBV-DNA was positive in 14 of them, with 2 cases of variant at 145, 1 case at 126 and 1 case at 134. Conclusion: In some patients with chronic B hepatitis with both positive HBsAg and HBsAb markers, as well as in some vaccine immunization failures, there were 'a' determinant variants, which might alter the antigenicity of HBsAg with escape from the neutralization of low HBsAb. The 'a' determinant variant might also affect the replication of the virus. In this study, no variant was shown in patients after successful liver transplantation. However, the number of patients was too small and the result was of no

  12. Quantitative HBsAg and HBeAg predict hepatitis B seroconversion after initiation of HAART in HIV-HBV coinfected individuals.

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    Gail V Matthews

    Full Text Available OBJECTIVE: Anti-HBe seroconversion and HBsAg loss are important therapeutic endpoints in patients with hepatitis B virus (HBV infection. Quantitative measures of hepatitis B surface antigen (qHBsAg and e antigen (qHBeAg have been identified as potentially useful indicators of therapeutic response in HBV monoinfection. The aim of this study was to examine serological change including quantitative biomarkers in HIV-HBV coinfected patients initiating HBV active antiretroviral therapy (ART. METHODS: HIV-HBV coinfected individuals from Thailand were followed for up to 168 weeks post ART. Rates and associations of qualitative serological change were determined. Longitudinal changes in qHBsAg and qHBeAg were measured and their utility as predictors of response examined. RESULTS: Forty seven patients were included of whom 27 (57% were HBeAg positive at baseline. Median CD4 count was 48 cells/mm(3. Over a median follow-up of 108 weeks 48% (13/27 lost HBeAg, 12/27 (44% achieved anti-HBe seroconversion and 13% (6/47 HBsAg loss. Anti-HBe seroconversion was associated with higher baseline ALT (p = 0.034, lower qHBsAg (p = 0.015, lower qHBeAg (p = 0.031 and greater HBV DNA decline to week 24 (p = 0.045. Sensitivity and specificity for qHBsAg and qHBeAg decline of >0.5 log at week 12 and >1.0 log at week 24 were high for both anti-HBe seroconversion and HBsAg loss. CONCLUSIONS: Rates of serological change in these HIV-HBV coinfected individuals with advanced immunodeficiency initiating HBV-active ART were high. Baseline and on treatment factors were identified that were associated with a greater likelihood of subsequent anti-HBe seroconversion, including both quantitative HBsAg and HBeAg, suggesting these biomarkers may have utility in this clinical setting.

  13. 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.

  14. GAMBARAN ANTI HBc POSITIF PADA DONOR DARAH DENGAN HbsAG NEGATIF

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    Susila Sastri

    2009-09-01

    Full Text Available AbstrakPemeriksaan HBsAg saja untuk skrining hepatitis B (HBV belum dapat menjamin donor darah bebas dari HBV sehingga darah donor belum memenuhi persyaratan untuk ditransfusikan. Darah donor yang akan ditranfusikan hendaklah memenuhi syarat diantaranya donor tidak pernah menderita HBV. Skrining darah donor terhadap HBV pada PMI hanya dengan uji HBsAg saja dimana HBsAg akan negatif pada stadium HBV tertentu, pada hal donor menderita atau dalam masa penyembuhan HBV. Anti-HBc dapat memberi informasi tentang perjalanan HBV bila digabungkan dengan marker HBV lain dan anti-HBc bertahan lebih lama dalam darah dibandingkan dengan marker lain. Donor darah HBsAg negatif dengan anti-HBc positif dari beberapa penelitian terdahulu masih ada yang mengandung HBV-DNA dan dapat menularkan HBV.Telah dilakukan penelitian terhadap donor darah dengan melakukan uji anti-HBc secara deskriptif terhadap donor darah dengan HBsAg negatif (n=100 pada UTD PMI Cabang Padang secara cross sectional study. Sampel diambil secara proportional random sampling. Darah sampel adalah darah HBsAg negatif dengan VDRL, HVC, HIV  negatif , semuanya diperiksa dengan dengan ELISATujuan penelitian untuk melihat gambaran anti-HBc positif pada donor darah dengan HBsAg negatif dan melihat hubungan antara indeks HBsAg dengan indeks anti-HBc. Pemeriksaan anti-HBc dilakukan dengan ELISA, alat dan reagen keluaran yang sama.Hasil penelitian menunjukkan frekuensi anti-HBc positif pada donor darah dengan HBsAg negatif sebanyak 27%, terutama pada laki-laki berumur antara 20-29 tahun (44,4%. Terdapat korelasi positif antara indeks HBsAg negatif dengan indeks anti-HBc (r = 0,02. Anti-HBc positif banyak ditemukan pada indeks HBsAg negatif 0,21-0,60 (76%.Kesimpulan, darah donor dengan HBsAg negatif yang selama ini dianggap aman untuk transfusi terbukti masih mungkin menularkan HBV dengan ditemukannya anti-HBc yang positif. Karena itu perlu pemeriksaan lanjutan DNA HBV pada donor darah dengan HbsAg

  15. Optimisation of secretion of recombinant HBsAg virus-like particles: Impact on the development of HIV-1/HBV bivalent vaccines

    NARCIS (Netherlands)

    Michel, Marie; Lone, Yu-Chun; Centlivre, Mireille; Roux, Pascal; Wain-Hobson, Simon; Sala, Monica

    2007-01-01

    The hepatitis B surface antigen (HBsAg) assembles into virus-like particles (VLPs) that can be used as carrier of immunogenic peptides for the development of bivalent vaccine candidates. It is shown here that by respecting certain qualitative features of mammalian preS1 and preS2 protein domains

  16. Virus-specific immune response in HBeAg-negative chronic hepatitis B: relationship with clinical profile and HBsAg serum levels.

    Directory of Open Access Journals (Sweden)

    Elisabetta Loggi

    Full Text Available BACKGROUND AIMS: The immune impairment characterizing chronic hepatitis B (cHBV infection is thought to be the consequence of persistent exposure to viral antigens. However, the immune correlates of different clinical stages of cHBV and their relation with different levels of HBsAg have not been investigated. The aim of the present study was to evaluate the relationship between HBV-specific T cells response and the degree of in vivo HBV control and HBsAg serum levels in HBeAg-HBeAb+ cHBV. METHODS: Peripheral blood mononuclear cells from 42 patients with different clinical profiles (treatment-suppressed, inactive carriers and active hepatitis of cHBV, 6 patients with resolved HBV infection and 10 HBV-uninfected individuals were tested with overlapping peptides spanning the entire HBV proteome. The frequency and magnitude of HBV-specific T cell responses was assessed by IFNγ ELISPOT assay. Serum HBsAg was quantified with a chemiluminescent immunoassay. RESULTS: The total breadth and magnitude of HBV-specific T cell responses did not differ significantly between the four groups. However, inactive carriers targeted preferentially the core region. In untreated patients, the breadth of the anti-core specific T cell response was inversely correlated with serum HBsAg concentrations as well as HBV-DNA and ALT levels and was significantly different in patients with HBsAg levels either above or below 1000 IU/mL. The same inverse association between anti-core T cell response and HBsAg levels was found in treated patients. CONCLUSIONS: Different clinical outcomes of cHBV infection are associated with the magnitude, breadth and specificity of the HBV-specific T cell response. Especially, robust anti-core T cell responses were found in the presence of reduced HBsAg serum levels, suggesting that core-specific T cell responses can mediate a protective effect on HBV control.

  17. HBsAg carrier status and the association between gestational diabetes with increased serum ferritin concentration in Chinese women.

    Science.gov (United States)

    Lao, Terence T; Tse, Ka-Yu; Chan, Louis Y; Tam, Kar-Fai; Ho, Lai-Fong

    2003-11-01

    To determine whether the high prevalence of hepatitis B surface antigen (HBsAg) carriage in our population can explain the previous observation of an association between increased maternal serum ferritin concentration and gestational diabetes in Hong Kong Chinese women. A retrospective study was performed on 767 nonanemic women with singleton pregnancy who had iron status assessed at 28-30 weeks. The result of the routine antenatal HBsAg screening was retrieved from patient records. The HBsAg-positive and -negative groups were compared for maternal characteristics, prevalence of gestational diabetes in the third trimester, prevalence of high serum ferritin and iron concentrations, and transferrin saturation, which is defined as a value in the highest quartile established by the measurements obtained from the HBsAg-negative group. The incidences of oral glucose tolerance test and gestational diabetes were significantly increased in the HBsAg-positive group. The HBsAg-positive women with gestational diabetes had significantly increased prevalence of high serum ferritin compared with the HBsAg-negative women, irrespective of the latter's gestational diabetes status. Multiple logistic regression analysis confirmed the independent association between HBsAg carrier status with gestational diabetes (relative risk 3.51, 95% CI 1.83-6.73) but excluded high ferritin as an independent factor. Our results indicate that maternal HBsAg carriage could explain in part the association between increased serum ferritin concentration with gestational diabetes in Hong Kong Chinese women, and that HBsAg carrier status is an independent risk factor for gestational diabetes.

  18. Lack of immune potentiation by complexing HBsAg in a heat-inactivated hepatitis B vaccine with antibody in hepatitis B immunoglobulin

    NARCIS (Netherlands)

    Lelie, P. N.; van Amelsfoort, P. J.; Martine de Groot, C. S.; Bakker, E.; Schaasberg, W.; Niessen, J. C.; Reesink, H. W.

    1989-01-01

    In a randomized, dose-response study among 305 health care workers, we examined whether the immunogenicity of a heat-inactivated hepatitis B vaccine could be enhanced when HBsAg was complexed by anti-HBs contained in hepatitis B immunoglobulin either at equivalent proportions or at 10-fold antigen

  19. 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

  20. Hepatitis B virus induces IL-23 production in antigen presenting cells and causes liver damage via the IL-23/IL-17 axis.

    Directory of Open Access Journals (Sweden)

    Qinghong Wang

    Full Text Available IL-23 regulates myriad processes in the innate and adaptive immune systems, and is a critical mediator of the proinflammatory effects exerted by Th17 cells in many diseases. In this study, we investigated whether and how hepatitis B virus (HBV causes liver damage directly through the IL-23 signaling pathway. In biopsied liver tissues from HBV-infected patients, expression of both IL-23 and IL-23R was remarkably elevated. In vivo observations also indicated that the main sources of IL-23 were myeloid dendritic cells (mDCs and macrophages. Analysis of in vitro differentiated immature DCs and macrophages isolated from healthy donors revealed that the HBV surface antigen (HBsAg efficiently induces IL-23 secretion in a mannose receptor (MR-dependent manner. Culture with an endosomal acidification inhibitor and the dynamin inhibitor showed that, upon binding to the MR, the HBsAg is taken up by mDCs and macrophages through an endocytosis mechanism. In contrast, although the HBV core antigen (HBcAg can also stimulate IL-23 secretion from mDCs, the process was MR- and endocytosis-independent. In addition, IL-23 was shown to be indispensible for HBsAg-stimulated differentiation of naïve CD4(+ T cells into Th17 cells, which were determined to be the primary source of IL-17 in HBV-infected livers. The cognate receptor, IL-17R, was found to exist on the hepatic stellate cells and mDCs, both of which might represent the potential target cells of IL-17 in hepatitis B disease. These data provide novel insights into a yet unrecognized mechanism of HBV-induced hepatitis, by which increases in IL-23 expression, through an MR/endocytosis-dependent or -independent manner, produce liver damage through the IL-23/IL-17 axis.

  1. Frequency of pregnant women with HBsAg in a Brazilian community Freqüência de gestantes portadoras do HBsAg em uma comunidade brasileira

    Directory of Open Access Journals (Sweden)

    Geraldo Duarte

    1997-01-01

    Full Text Available The work reported here points up the real benefits provided by neonatal immunoprophylaxis of newborns delivered by mothers who are seropositive for the hepatitis B virus surface antigen HBsAg and underscores the need to properly identify such mothers in Brazil so that immunoprophylaxis can be undertaken. To help determine levels of hepatitis B virus (HBV infection and seropositivity for various HBV markers among pregnant women in Southeast Brazil, investigators studied 7992 pregnant women delivering at the Clinical Hospital of the University of São Paulo's Ribeirão Preto School of Medicine in Ribeirão Preto, Brazil. Seroreactivity for HBsAg was determined first by serologic screening with an enzyme-linked immunosorbent assay (ELISA procedure in which the sera were incubated for 2 hours and then by confirmation with another ELISA in which the sera were incubated for 18 hours. Subsequently, tests for anti-HBsAg, HBeAg, anti-HBeAg, and anti-HBcAg markers were conducted using confirmed positive samples. Initial screening found 84 of the 7992 samples (1.05%, 95% CI: 0.84-1.30 to be positive for HBsAg; however, this HBsAg positivity was confirmed in only 76 (0.95%, 95% CI: 0.75-1.19. The positivity rate was significantly higher among subjects whose pregnancies terminated in miscarriage (1.84% than among those with live births (0.83% (chi2, Yates correction = 7.6; P = 0.005. Anamnesis was able to identify HBV risk factors in only 27.6% of the confirmed HBsAg-positive subjects or close household contacts. However, 21.3% (95% CI: 1.04-30.56 of the confirmed HBsAg-positive subjects were found positive for HBeAg, indicating a high risk of vertical transmission of the virus. These results demonstrate a need to conduct specific serologic research at term, in order to provide effective neonatal immunoprophylactic benefits.Visando aferir a tasa de reatividade sérica do HBsAg e de outros marcadores da infecção pelo VHB em parturientes, além de avaliar

  2. Immobilization of yeast cells by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Fujimura, T.; Kaetsu, I.

    1982-01-01

    Radiation-induced polymerization method was applied to the immobilization of yeast cells. The effects of irradiation, cooling and monomer, which are neccessary for polymerization, were recovered completely by subsequent aerobical incubation of yeast cells. The ethanol productive in immobilized yeast cells increased with the increase of aerobical incubation period. The growth of yeast cells in immobilized yeast cells was indicated. The maximum ethanol productivity in immobilized yeast cell system was around three times as much as that in free yeast cell system. (orig.)

  3. Serological profile of incidentally detected asymptomatic HBsAg positive subjects (IDAHS)

    International Nuclear Information System (INIS)

    Khokhar, N.; Gill, M.L.

    2004-01-01

    Objective: To evaluate the serological profile of patients with incidentally detected positive hepatitis-B surface antigen (HBsAg) and to asses the risk factors. Design: An observational study. Place and Duration of Study: This study was conducted at Shifa International Hospital, Islamabad from 1999 to 2003. Patients and Methods: All patients who presented to gastroenterology clinic of Shifa Intentional Hospital, Islamabad with positive HBsAg, detected incidentally, were tested for alamine transaminase (ALT), hepatitis Beantigen (HBeAg) and in certain cases hepatitis-B virus DNA (HBV DNA) by polymerase chain reaction (PCR). Their risk factors for acquisition of infection were assessed with specific questions. Results: A total of 224 patients were examined. One hundred sixty-four (73.2%) were male and 60 (26.8%) female. Mean age of all the subjects was 32.45 plus minus 11.85 years. Out of 224 patients, 48 (21.4%) were positive for HBeAg and 176 (78.6%) were negative. Out of 48 subjects who were positive for HBeAg, 36 underwent HBV DNA determination and 32 (88.8%) were positive for HBV DNA. Out of 176 subjects who had negative HBeAg, 46 had elevated ALT and in those HBV DNA was performed and 14 had positive HBV DNA. Most common risk factors detected in these patients were intramuscular injections and surgery, however, in a large number, risk factors were unknown. Conclusion: Twenty-one percent asymptomatic subjects with positive HBsAg were found to be HBeAg positive. A large number of subjects with negative HBeAg had HBV DNA positive suggesting presence of precore mutants. Intramuscular injections and surgery were noted to be frequent risk factors in these subjects. (author)

  4. [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.

  5. Micropropagation of transgenic lettuce containing HBsAg as a method of mass-scale production of standardised plant material for biofarming purposes.

    Science.gov (United States)

    Pniewski, Tomasz; Czyż, Marcin; Wyrwa, Katarzyna; Bociąg, Piotr; Krajewski, Paweł; Kapusta, Józef

    2017-01-01

    Micropropagation protocol of transgenic lettuce bearing S-, M- and L-HBsAg was developed for increased production of uniformised material for oral vaccine preparation. Effective manufacturing of plant-based biopharmaceuticals, including oral vaccines, depends on sufficient content of a protein of interest in the initial material and its efficient conversion into an administrable formulation. However, stable production of plants with a uniformised antigen content is equally important for reproducible processing. This can be provided by micropropagation techniques. Here, we present a protocol for micropropagation of transgenic lettuce lines bearing HBV surface antigens: S-, M- and L-HBsAg. These were multiplied through axillary buds to avoid the risk of somaclonal variation. Micropropagation effectiveness reached 3.5-5.7 per passage, which implies potential production of up to 6600 plant clones within a maximum 5 months. Multiplication and rooting rates were statistically homogenous for most transgenic and control plants. For most lines, more than 90 % of clones obtained via in vitro micropropagation had HBsAg content as high as reference plants directly developed from seeds. Clones were also several times more uniform in HBsAg expression. Variation coefficients of HBsAg content did not exceed 10 % for approximately 40-85 % of clones, or reached a maximum 20 % for 90 % of all clones. Tissue culture did not affect total and leaf biomass yields. Seed production for clones was decreased insignificantly and did not impact progeny condition. Micropropagation facilitates a substantial increase in the production of lettuce plants with high and considerably equalised HBsAg contents. This, together with the previously reported optimisation of plant tissue processing and its long-term stability, constitutes a successive step in manufacturing of a standardised anti-HBV oral vaccine of reliable efficacy.

  6. 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.

  7. [Comparison of the clinical performance of the ECLusys HBsAg II assay with the Lumipulse f and HISCL 2000-i HBsAg screening assays].

    Science.gov (United States)

    Sugiura, Aya; Iwahara, Kunihiro; Suga, Yasuyuki; Uchiyama, Sachinori; Maekawa, Masato

    2012-02-01

    We compared the ECLusys HBsAgII (ECL HBsAg) assay to the Lumipulse Forte (LPf HBsAg) and HISCL (HIS HBsAg) assays. Measurement of dilution panels for which the WHO HBsAg international reference panel was the parent specimen revealed that the ECL and HIS assays enabled detection to a theoretical level of 0.04 IU/mL, whereas the LPf assay enabled detection to a level of 0.08 IU/mL. In a specificity test using high RF positive specimens (n = 33), pregnancy specimens (n = 35), cytomegalovirus antibody positive specimens (n = 36), and high M protein positive specimens (n = 21) that were confirmed negative for HBsAg by the LPf assay, negative results were obtained for all specimens on the HIS assay, but the ECL assay yielded a positive result for one of the high RF positive specimens. This individual was suggested on further testing to be an HBV carrier who was strongly positive for HBc antibody. In HBsAg mutants detection test, the detection rate was 92.3% with the ECL assay and 69.2% with the HIS assay. In a correlation test using routinely collected clinical specimens (n = 155), including positive stock specimens, aside from the one case where the LPf assay gave a negative result but both the ECL and HIS assays gave positive results, all of the results were consistent for all specimens. The above results confirmed that the ECL assay is both highly sensitive and specific, and also enables a high rate of HBsAg mutant detection.

  8. HBsAg level and hepatitis B viral load correlation with focus on pregnancy

    Science.gov (United States)

    Belopolskaya, Maria; Avrutin, Viktor; Firsov, Sergey; Yakovlev, Alexey

    2015-01-01

    Background Viral load measurement is necessary to estimate mother-to-child transmission risk for women with chronic hepatitis B (CHB), however, it is expensive. The present study aimed to investigate the relationship between HBsAg and hepatitis B virus (HBV) DNA levels, and to determine potential applications of HBsAg level monitoring for estimating viral load. Methods 85 patients with CHB (31 pregnant women, 26 non-pregnant women, 28 men) were included in the study. HBV DNA level was measured by real-time PCR, and HBsAg level by chemiluminescent immunoassay method. Dependency between viral load and HBsAg level was determined by Spearman correlation coefficient ρ. Results The correlation between HBsAg and HBV DNA levels was significant for all patients [ρ=0.3762 (P<0.0005; n=85)]. In the group of pregnant women, a low (unmeasurable) HBV DNA level led to a decrease in the Spearman coefficient ρ. In almost all cases a low level of the HBsAg corresponded to a low HBV DNA level. Only 2 patients had a low level of HBsAg and a relatively high viral load. By contrast, a high HBsAg level was observed in patients both with high and low viral load. Conclusions Correlation between HBsAg and HBV DNA levels is significant. In most cases, a low level of HBsAg indicates a low HBV DNA level, whereas a high HBsAg level does not always correspond to a high viral load. The measurement of HBV DNA level is necessary for pregnant women with a high HBsAg level. PMID:26127004

  9. 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.

  10. Human immunodeficiency virus (HIV) seropositivity and hepatitis B surface antigenemia (HBSAG) among blood donors in Benin city, Edo state, Nigeria.

    Science.gov (United States)

    Umolu, Patience Idia; Okoror, Lawrence Ehis; Orhue, Philip

    2005-03-01

    Human Immunodeficiency Virus and Hepatitis B virus are blood borne pathogens that can be transmitted through blood transfusion and could pose a huge problem in areas where mechanisms of ensuring blood safety are suspect. This study became necessary in a population where most of the blood for transfusion is from commercial blood donors. A total of 130 donors comprising 120 commercial donors and 10 voluntary donors were tested for antibodies to human immunodeficiency virus and hepatitis B surface antigen in Benin city using Immunocomb HIV - 1 and 2 Biospot kit and Quimica Clinica Aplicada direct latex agglutination method respectively. Thirteen (10%) samples were HIV seropositive and 7(5.8%) were HBsAg positive. The age bracket 18 - 25years had the highest numbers of donors and also had the highest number of HBsAg positive cases (7.8%) while the age group 29 - 38years had highest number of HIV seropositive cases. High prevalence of HIV antibodies and Hepatitis B surface antigen was found among commercial blood donors. Appropriate and compulsory screening of blood donors using sensitive methods, must be ensured to prevent post transfusion hepatitis and HIV.

  11. 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

  12. Inducibility of error-prone DNA repair in yeast

    International Nuclear Information System (INIS)

    Siede, W.; Eckardt, F.

    1984-01-01

    Whereas some experimental evidence suggests that mutagenesis in yeast after treatment with DNA-damaging agents involves inducible functions, a general-acting error-prone repair activity analogous to the SOS system of Escherichia coli has not yet been demonstrated. The current literature on the problem of inducibility of mutagenic repair in yeast is reviewed with emphasis on the differences in the experimental procedures applied. (orig.)

  13. 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.

  14. Low occurrence of HBsAg but high frequency of transient occult HBV infection in vaccinated and HBIG-administered infants born to HBsAg positive mothers.

    Science.gov (United States)

    Zhou, Shan; Li, Tingting; Allain, Jean-Pierre; Zhou, Bin; Zhang, Yuming; Zhong, Mei; Fu, Yongshui; Li, Chengyao

    2017-12-01

    The status of chronic and occult HBV infection (OBI) in neonatal hepatitis B vaccine and immunoglobulin (HBIG) vaccinated infants born to HBsAg+ mothers was investigated at a major hospital in China. Seventy-seven and 15 blood samples were collected in first or second follow-up detection from the vaccinated babies aged 3-36 months born to 43 HBsAg+ or plus 25 HBeAg+ mothers. HBV infection was analyzed between the paired baby and mother by serology and DNA analysis. Among 77 children born to 68 HBsAg+ mothers, 3.9% (3/77) were HBsAg+, and 36.4% (28/77) were HBV DNA+/HBsAg- (OBIs) by a single PCR, respectively. Thirteen of 28 HBV DNA+/HBsAg- samples were conformed by two PCRs or S sequence, which accounted for 16.9% (13/77) of children. Three HBsAg+ and six OBIs were genotyped in consistent with their mother's HBV strains. Of 77 babies' blood samples, anti-HBs reactivity varied slightly according to age groups, while passively transmitted anti-HBc reactivity declined from 100% high reactivity at age 3-5 months to mostly negative at age ≥12 months. Babies with apparent OBI had higher levels of anti-HBc and lower levels of anti-HBs than those without OBI but all eight OBI babies with second follow-up samples became HBV DNA negative beyond 1 year of age. The vaccinated infants born to HBsAg+ mothers presented the low rate of HBsAg occurrence as vaccination failure and high frequency of viral persistence in the form of transient OBIs since no evidence of active HBV infection occurred beyond 1 year of age. © 2017 Wiley Periodicals, Inc.

  15. Characterization of the respiration-induced yeast mitochondrial permeability transition pore.

    Science.gov (United States)

    Bradshaw, Patrick C; Pfeiffer, Douglas R

    2013-12-01

    When isolated mitochondria from the yeast Saccharomyces cerevisiae oxidize respiratory substrates in the absence of phosphate and ADP, the yeast mitochondrial unselective channel, also called the yeast permeability transition pore (yPTP), opens in the inner membrane, dissipating the electrochemical gradient. ATP also induces yPTP opening. yPTP opening allows mannitol transport into isolated mitochondria of laboratory yeast strains, but mannitol is not readily permeable through the yPTP in an industrial yeast strain, Yeast Foam. The presence of oligomycin, an inhibitor of ATP synthase, allowed for respiration-induced mannitol permeability in mitochondria from this strain. Potassium (K+) had varied effects on the respiration-induced yPTP, depending on the concentration of the respiratory substrate added. At low respiratory substrate concentrations K+ inhibited respiration-induced yPTP opening, while at high substrate concentrations this effect diminished. However, at the high respiratory substrate concentrations, the presence of K+ partially prevented phosphate inhibition of yPTP opening. Phosphate was found to inhibit respiration-induced yPTP opening by binding a site on the matrix space side of the inner membrane in addition to its known inhibitory effect of donating protons to the matrix space to prevent the pH change necessary for yPTP opening. The respiration-induced yPTP was also inhibited by NAD, Mg2+, NH4 + or the oxyanion vanadate polymerized to decavanadate. The results demonstrate similar effectors of the respiration-induced yPTP as those previously described for the ATP-induced yPTP and reconcile previous strain-dependent differences in yPTP solute selectivity. Copyright © 2013 John Wiley & Sons, Ltd.

  16. Association of social class in HBsAg and hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Pervez, T.; Anwar, M. S.

    2001-01-01

    Objective: To find out the social class difference in relation to frequency of HBsAg and hepatocellular carcinoma in our population. Design: An analytical study. Place and Duration of Study: This study was conducted in Oncology Department, Services Hospital, Lahore from December 1997 to December 2000. Subjects and Methods: The HBsAg positive voluntary and apparently healthy blood donors were grouped into three, based on monthly income. Lower socioeconomic group and had monthly income less than 3,000 Pakistani rupees, middle socioeconomic group had monthly income between 3,000-10,000 rupees and upper socioeconomic group had income of more than 10,000 Pakistani rupees. On the same pattern patients suffering from hepatocellular carcinoma coming for treatment were also grouped. During this period, 1000 blood donors were screened for HBsAg and 95 biopsy proven liver cancer by causes were treated. Medical and demographic data of all subjects were recorded. HBsAg test was performed immuno-chromatographic technique using Daina Screen HBsAg kit manufactured by Dainabot Co. Ltd, Tokyo, Japan. Results: Patients from lower and middle social class had higher percentage (80% and 75%) of hepatocellular carcinoma as compared to higher social class (66.6%). In the healthy asymptomatic blood donors lower social class had higher (13.76%) HBsAg positively as compared to middle social class (11.25%) and higher social class (8.06%). Conclusion: Preventive measures should be taken in identifying and reducing factors predisposing high frequency of these conditions. (author)

  17. Radioimmunologic determination of hepatitis B antigen (HBsAG) in selected groups of persons and in special blood preparations

    Energy Technology Data Exchange (ETDEWEB)

    Lipsic, T; Geso, L [Clinic of Haematology and Blood Transfusion, Bratislava (Czechoslovakia)

    1978-06-30

    Presence of HBsAg was investigated by the RIA method in groups: exposed patients, blood donors, medical staff and different plasma preparations, namely: antihaemophilic cryoprotein (AHCp), Fibrinogen, I. Cohn's fraction and PPSB. 1789 samples of serum or converted material (plasma and its fractions) were investigated. In 405 cases AUSRIA-I method was used, the remaining 1384 cases were investigated by AUSRIA-II. Data are tabulated.

  18. The variability of hepatitis B envelope is associated with HBs antigen persistence in either chronic or acute HBV genotype A infection.

    Science.gov (United States)

    Eschlimann, Marine; Malvé, Brice; Velay, Aurélie; Fenaux, Honorine; Berger, Sibel; Frippiat, Jean-Pol; Zoulim, Fabien; Bensenane, Mouni; Bronowicki, Jean-Pierre; Goehringer, François; May, Thierry; Jeulin, Hélène; Schvoerer, Evelyne

    2017-09-01

    More than 240 million people are chronically infected by hepatitis B virus (HBV) worldwide. Envelope proteins play a crucial role in viral cellular entry and immune recognition. The loss of HBs antigen (HBsAg) correlated with a good clinical prognosis is rarely achieved with or without treatment (3-16%). HBV envelope variability was investigated according to HBsAg persistence. The cohort consisted of 15 HBV genotype A-infected patients divided into "resolvers", with HBsAg clearance, and "non-resolvers", with HBsAg persistence and in subgroups: acute (n=5, AHBV) or chronic infection (n=4, CHBV) and HBV/HIV coinfection (n=6, CHBV/HIV). HBV S and preS sequences were studied by direct and ultra-deep sequencing. Amino acid sequences were analyzed with bioinformatics for predicted antigenicity. In S gene, the complexity was lower in AHBV than in chronic-infected patients (p=0.046). Major mutations, detected using direct sequencing, were more frequent in AHBV developing chronicity (p=0.01) than in AHBV resolvers. In the Major Hydrophilic Region, more frequent mutations were observed in non-resolvers versus resolvers (p=0.047) and non-resolvers tended to have more haplotypes with a reduced predicted antigenicity (p=0.07). Most of the mutations in preS/S region were found rather in epitopic than in non-epitopic areas (p=0.025). Interestingly, the mutation sY161F found in 3/8 non-resolvers was associated with a decrease in predicted antigenicity (28%; AnTheProt). HBsAg persistence was correlated with mutations and deletions in areas playing a key role in immune recognition. These data suggest that variability in HBV envelope could favor immune escape in various clinical settings of HBV genotype A-infected patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. 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.

  20. 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

  1. Prevalence of HBsAg and anti-HBs among delivering women.

    Science.gov (United States)

    Sabău, M; Căpîlnă; Kiss, E

    1979-01-01

    A survey of 2,500 delivering women revealed a 7.6% incidence of past infection with hepatitis B virus (HBV) (HBsAg or anti-HBs). Only 5.9% of the anti-HBs-positive mothers had a possible history of parenteral exposure to hepatitis B and none of the 55 HBsAg carriers had such a history. The findings suggest that HBV is endemic and that it is probably spread in part by nonparenteral means. The high rates of HBsAg and anti-HBs point to the possible preventive value of routine screenings for this system among pregnant women.

  2. Higher baseline viral diversity correlates with lower HBsAg decline following PEGylated interferon-alpha therapy in patients with HBeAg-positive chronic hepatitis B.

    Science.gov (United States)

    Li, Hu; Zhang, Li; Ren, Hong; Hu, Peng

    2018-01-01

    Viral diversity seems to predict treatment outcomes in certain viral infections. The aim of this study was to evaluate the association between baseline intra-patient viral diversity and hepatitis B surface antigen (HBsAg) decline following PEGylated interferon-alpha (Peg-IFN-α) therapy. Twenty-six HBeAg-positive patients who were treated with Peg-IFN-α were enrolled. Nested polymerase chain reaction (PCR), cloning, and sequencing of the hepatitis B virus S gene were performed on baseline samples, and normalized Shannon entropy (Sn) was calculated as a measure of small hepatitis B surface protein (SHBs) diversity. Multiple regression analysis was used to estimate the association between baseline Sn and HBsAg decline. Of the 26 patients enrolled in the study, 65.4% were male and 61.5% were infected with hepatitis B virus genotype B. The median HBsAg level at baseline was 4.5 log 10 IU/mL (interquartile range: 4.1-4.9) and declined to 3.0 log 10 IU/mL (interquartile range: 1.7-3.9) after 48 weeks of Peg-IFN-α treatment. In models adjusted for baseline alanine aminotransferase (ALT) and HBsAg, the adjusted coefficients (95% CI) for ΔHBsAg and relative percentage HBsAg decrease were -1.3 (-2.5, -0.2) log 10 IU/mL for higher SHBs diversity (Sn≥0.58) patients and -26.4% (-50.2%, -2.5%) for lower diversity (Sndiversity. Baseline intra-patient SHBs diversity was inverse to HBsAg decline in HBeAg-positive chronic hepatitis B (CHB) patients receiving Peg-IFN-α monotherapy. Also, more sequence variations within the "a" determinant upstream flanking region and the first loop of the "a" determinant were the main sources of the higher SHBs diversity.

  3. A novel therapeutic hepatitis B vaccine induces cellular and humoral immune responses and breaks tolerance in hepatitis B virus (HBV) transgenic mice.

    Science.gov (United States)

    Buchmann, Pascale; Dembek, Claudia; Kuklick, Larissa; Jäger, Clemens; Tedjokusumo, Raindy; von Freyend, Miriam John; Drebber, Uta; Janowicz, Zbigniew; Melber, Karl; Protzer, Ulrike

    2013-02-06

    Therapeutic vaccines are currently being developed for chronic hepatitis B and C. As an alternative to long-term antiviral treatment or to support only partially effective therapy, they should activate the patient's immune system effectively to fight and finally control the virus. A paradigm of therapeutic vaccination is the potent induction of T-cell responses against key viral antigens - besides activation of a humoral immune response. We have evaluated the potential of a novel vaccine formulation comprising particulate hepatitis B surface (HBsAg) and core antigen (HBcAg), and the saponin-based ISCOMATRIX™ adjuvant for its ability to stimulate T and B cell responses in C57BL/6 mice and its ability to break tolerance in syngeneic HBV transgenic (HBVtg) mice. In C57BL/6 mice, the vaccine induced multifunctional HBsAg- and HBcAg-specific CD8+ T cells detected by staining for IFNγ, TNFα and IL-2, as well as high antibody titers against both antigens. Vaccination of HBVtg animals induced potent HBsAg- and HBcAg-specific CD8+ T-cell responses in spleens and HBcAg-specific CD8+ T-cell responses in livers as well as anti-HBs seroconversion two weeks post injection. Vaccination further reduced HBcAg expression in livers of HBVtg mice without causing liver damage. In summary, this study demonstrates therapeutic efficacy of a novel vaccine formulation in a mouse model of immunotolerant, chronic HBV infection. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. 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.

  5. Characterization of the Respiration-Induced Yeast Mitochondrial Permeability Transition Pore

    OpenAIRE

    Bradshaw, Patrick C.; Pfeiffer, Douglas R.

    2013-01-01

    When isolated mitochondria from the yeast Saccharomyces cerevisiae oxidize respiratory substrates in the absence of phosphate and ADP, the yeast mitochondrial unselective channel, also called the yeast permeability transition pore (yPTP), opens in the inner membrane dissipating the electrochemical gradient. ATP also induces yPTP opening. yPTP opening allows mannitol transport into isolated mitochondria of laboratory yeast strains, but mannitol is not readily permeable throug...

  6. 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.

  7. Delayed clearance of serum HBsAg in compensated cirrhosis B

    DEFF Research Database (Denmark)

    Fattovich, G; Giustina, G; Sanchez-Tapias, J

    1998-01-01

    The aim of this study was to evaluate the incidence, prognostic factors and clinical significance of delayed clearance of serum HBsAg in compensated cirrhosis B.......The aim of this study was to evaluate the incidence, prognostic factors and clinical significance of delayed clearance of serum HBsAg in compensated cirrhosis B....

  8. Low serum hyaluronic acid levels associated with spontaneous HBsAg clearance

    NARCIS (Netherlands)

    Harkisoen, S.; Arends, J. E.; van den Hoek, A.; van Erpecum, K. J.; Boland, G. J.; Hoepelman, A. I. M.

    2015-01-01

    Purpose The pathophysiological underlying mechanism of spontaneous HBsAg clearance in hepatitis B virus (HBV) infected patients is largely unknown. However, serum hyaluronic acid (sHA) plays a role in liver fibrosis progression and reversely could serve as a potential biomarker for HBsAg clearance.

  9. Specificity of antigens on UV radiation-induced antigenic tumor cell variants measured in vitro and in vivo

    International Nuclear Information System (INIS)

    Hostetler, L.W.; Romerdahl, C.A.; Kripke, M.L.

    1989-01-01

    The purpose of this study was to determine whether antigenic variants cross-react immunologically with the parental tumor and whether the UVR-associated antigen unique to UVR-induced tumors is also present on the variants. Antigenic (regressor) variants and nonimmunogenic (progressor) clones derived from UV-irradiated cultures of the C3H K1735 melanoma and SF19 spontaneous fibrosarcoma cell lines were used to address these questions. In an in vivo immunization and challenge assay, the antigenic variants did not induce cross-protection among themselves, but each induced immunity against the immunizing variant, the parent tumor cells, and nonimmunogenic clones derived from UV-irradiated parent cultures. Therefore, the variants can be used to induce in mice a protective immunity that prevents the growth of the parent tumor and nonimmunogenic clones, but not other antigenic variants. In contrast, immunization with cells of the parental tumor or the nonimmunogenic clones induced no protective immunity against challenge with any of the cell lines. Utilizing the K1735 melanoma-derived cell lines in vitro, T-helper (Th) cells isolated from tumor-immunized mice were tested for cross-reactivity by their ability to collaborate with trinitrophenyl-primed B-cells in the presence of trinitrophenyl-conjugated tumor cells. Also, the cross-reactivity of cytotoxic T-lymphocytes from tumor-immunized mice was assessed by a 4-h 51Cr-release assay. Antigenic variants induced cytotoxic T-lymphocytes and Th activity that was higher than that induced by the parent tumor and nonimmunogenic clones from the UVR-exposed parent tumor and cross-reacted with the parental tumor cells and nonimmunogenic clones, but not with other antigenic variants

  10. [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.

  11. 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

  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. 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.

  14. 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

  15. Detection of Hepatitis B Virus Antigens in Paraffin-embedded Liver Specimens from the Amazon Region, Brazil

    Directory of Open Access Journals (Sweden)

    Simonetti SRR

    2002-01-01

    Full Text Available Hepatic viscerotomy of paraffin-preserved old specimens, collected in the period from 1934 to 1967, were analyzed by immunohistochemical assays to detect hepatitis B, hepatitis D, dengue and yellow fever virus antigens. The material belongs to the Yellow Fever Collection, Department of Pathology, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil and the cases were diagnosed at that time according to clinical aspects and histopathological findings reporting viral hepatitis, yellow fever, focal necrosis and hepatic atrophy. From the 79 specimens, 69 were collected at the Labrea Region and the other 10 in different other localities in the Amazon Region. The five micra thick histological slices were analyzed for the presence of hepatitis B surface antigen (HBsAg and hepatitis B core antigen (HBcAg by immunoperoxidase technique. An immunofluorescence assay was applied to the detection of hepatitis D, yellow fever and dengue virus antigens. Nine (11.4% histological samples were HBsAg reactive and 5 (6.3% were HBcAg reactive. The oldest reactive sample was from 1934. Viral antigens related to the other pathologies were not detected in this study. Our results confirm that the methodology described may be used to elucidate the aetiology of hepatitis diseases even after a long time of conservation of the specimens.

  16. Historic and current hepatitis B viral DNA and quantitative HBsAg level are not associated with cirrhosis in non-Asian women with chronic hepatitis B.

    Science.gov (United States)

    Harkisoen, S; Arends, J E; van den Hoek, J A R; Whelan, J; van Erpecum, K J; Boland, G J; Hoepelman, A I M

    2014-12-01

    Some studies done in Asian patients have shown that serum levels of hepatitis B virus (HBV) DNA predict the development of cirrhosis. However, it is unclear whether this also applies for non-Asian patients. This study investigated historic and current HBV DNA and quantitative hepatitis B surface antigen (HBsAg) levels as predictors of cirrhosis in non-Asian women with chronic HBV. A retrospective cohort study of non-Asian women with chronic HBV was performed. Among other variables, HBV DNA and quantitative HBsAg levels were measured in stored historic serum samples obtained during pregnancy (period 1990-2004) and current serum samples (period 2011-2012) to determine any association with liver cirrhosis by liver stiffness measurement (LSM). One hundred and nineteen asymptomatic, treatment-naïve non-Asian women were included; the median number of years between the historic sample and the current sample was 17 (interquartile range (IQR) 13-20). The median historic log HBV DNA and quantitative log HBsAg levels were 2.5 (IQR 1.9-3.4) IU/ml and 4.2 (IQR 3.6-4.5) IU/ml, respectively. LSM diagnosed 14 patients (12%) with F3-F4 fibrosis, i.e. stiffness >8.1kPa. No association of cirrhosis was found with historic HBV DNA (relative risk (RR) 0.34, 95% confidence interval (CI) 0.05-2.44) or with the quantitative HBsAg level (HBsAg level >1000 IU/ml, RR 0.35, 95% CI 0.11-1.11). Multivariable analysis identified alcohol consumption (odds ratio (OR) 6.4, 95% CI 1.3-30.1), aspartate aminotransferase >0.5 times the upper limit of normal (OR 15.4, 95% CI 1.9-122.6), and prothrombin time (OR 12.0, 95% CI 1.2-120.4), but not HBV DNA or quantitative HBsAg level, to be independent predictors of the presence of cirrhosis. Neither historic nor current HBV DNA or the quantitative HBsAg level is associated with the development of HBV-related cirrhosis in non-Asian women. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Development of a Novel, Ultra-rapid Biosensor for the Qualitative Detection of Hepatitis B Virus-associated Antigens and Anti-HBV, Based on “Membrane-engineered” Fibroblast Cells with Virus-Specific Antibodies and Antigens

    Directory of Open Access Journals (Sweden)

    Antonios Perdikaris

    2009-03-01

    Full Text Available A novel miniature cell biosensor detection system for the detection of Hepatis B virus (HBV-associated antigens and anti-HBV is described. The biosensor is based on “membrane-engineered” Vero fibroblast cells immobilized in an alginate matrix. The membrane-engineering process involved the electroinsertion of anti-HBV specific antibodies (anti-HBs, anti-HBe or antigens (HBsAg in the membranes of the Vero cells. The attachment of a homologous antigen to the electroinserted antibody (or, respectively, of the antibody to the electroinserted antigen triggered specific changes to the cell membrane potential that were measured by appropriate microelectrodes, according to the principle of the Bioelectric Recognition Assay (BERA. The sensor was used for screening 133 clinical blood serum samples according to a double-blind protocol. Considerably higher sensor responses were observed against HBV-positive samples, compared with responses against negative samples or samples positive for heterologous hepatitis viruses such as Hepatitis C (HCV virus. Detection of anti-HBs antibodies was made possible by using a biosensor based on immobilized Vero cells bearing the respective antigen (HBsAg. The observed response was rapid (45 sec and quite reproducible. Fluorescence microscopy observations showed that attachment of HBV particles to cells membrane-engineered with anti-HBs was associated with a decrease of [Ca2+]cyt. The perspectives for using the novel biosensor as a qualitative, rapid screening, high throughput assay for HBV antigens and anti-HBs in clinical samples is discussed.

  18. 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.

  19. Kefiran suppresses antigen-induced mast cell activation.

    Science.gov (United States)

    Furuno, Tadahide; Nakanishi, Mamoru

    2012-01-01

    Kefir is a traditional fermented milk beverage produced by kefir grains in the Caucasian countries. Kefiran produced by Lactobacillus kefiranofaciens in kefir grains is an exopolysaccharide having a repeating structure with glucose and galactose residues in the chain sequence and has been suggested to exert many health-promoting effects such as immunomodulatory, hypotensive, hypocholesterolemic activities. Here we investigated the effects of kefiran on mast cell activation induced by antigen. Pretreatment with kefiran significantly inhibited antigen-induced Ca(2+) mobilization, degranulation, and tumor necrosis factor-α production in bone marrow-derived mast cells (BMMCs) in a dose-dependent manner. The phosphorylation of Akt, glycogen synthase kinase 3β, and extracellular signal-regulated kinases (ERKs) after antigen stimulation was also suppressed by pretreatment of BMMCs with kefiran. These findings indicate that kefiran suppresses mast cell degranulation and cytokine production by inhibiting the Akt and ERKs pathways, suggesting an anti-inflammatory effect for kefiran.

  20. 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

  1. Identification of salivary components that induce transition of hyphae to yeast in Candida albicans.

    Science.gov (United States)

    Leito, Jelani T D; Ligtenberg, Antoon J M; Nazmi, Kamran; Veerman, Enno C I

    2009-10-01

    Candida albicans, the major human fungal pathogen, undergoes a reversible morphological transition from single yeast cells to pseudohyphae and hyphae filaments. The hyphae form is considered the most invasive form of the fungus. The purpose of this study is to investigate the effect of saliva on hyphae growth of C. albicans. Candida albicans hyphae were inoculated in Roswell Park Memorial Institute medium with whole saliva, parotid saliva or buffer mimicking the saliva ion composition, and cultured for 18 h at 37 degrees C under aerobic conditions with 5% CO(2). Whole saliva and parotid saliva induced transition to yeast growth, whereas the culture with buffer remained in the hyphae form. Parotid saliva was fractionated on a reverse-phase C8 column and each fraction was tested for inducing transition to yeast growth. By immunoblotting, the salivary component in the active fraction was identified as statherin, a phosphoprotein of 43 amino acids that has been implicated in remineralization of the teeth. Synthetically made statherin induced transition of hyphae to yeast. By deletion of five amino acids at the negatively charged N-terminal site (DpSpSEE), yeast-inducing activity and binding to C. albicans were increased. In conclusion, statherin induces transition to yeast of C. albicans hyphae and may thus contribute to the oral defense against candidiasis.

  2. 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.

  3. WARBURG EFFECT AND TRANSLOCATION-INDUCED GENOMIC INSTABILITY: TWO YEAST MODELS FOR CANCER CELLS

    Directory of Open Access Journals (Sweden)

    Valentina eTosato

    2013-01-01

    Full Text Available Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression i the activity of pyruvate kinase (PK, which recapitulates metabolic features of cancer cells, including the Warburg effect, and ii Bridge-Induced chromosome Translocation (BIT mimicking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect, and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, pyruvate kinase, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and posttranslational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (translocants, between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the Bridge-Induced Translocation system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

  4. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype

    Directory of Open Access Journals (Sweden)

    Ruslana Vasylkovska

    2015-01-01

    Full Text Available Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii metabolic and growth rates as well as catalase activity play an important role in H2O2-induced hormetic response in yeast.

  5. 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

  6. HBsAg RIA QUICK and Anti-HBs RIA QUICK. Information of a new technique of radioimmunoassay of hepatitis B virus surface antigen and the corresponding antibody using kits by IMMUNO Vienna

    Energy Technology Data Exchange (ETDEWEB)

    Kselikova, M; Urbankova, J

    1985-11-01

    With regard to the high sensitivity of HBsAg and anti-HBs detection using kits HBsAg RIA QUICK and Anti-HBs RIA QUICK, and with regard to the excellent technical set-up which substantially reduces demands on manual work and eliminates the need to equip the department with a rinser, and also with regard to the lower price as compared with similar kits by Abbott Co., the above mentioned two kits will be imported to Czechoslovakia.

  7. Specificity of mutations induced by carbon ions in budding yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Matuo, Youichirou; Nishijima, Shigehiro; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi; Shimizu, Kikuo

    2006-01-01

    To investigate the nature of mutations induced by accelerated ions in eukaryotic cells, the effects of carbon-ion irradiation were compared with those of γ-ray irradiation in the budding yeast Saccharomyces cerevisiae. The mutational effect and specificity of carbon-ion beams were studied in the URA3 gene of the yeast. Our experiments showed that the carbon ions generated more than 10 times the number of mutations induced by γ-rays, and that the types of base changes induced by carbon ions include transversions (68.7%), transitions (13.7%) and deletions/insertions (17.6%). The transversions were mainly G:C → T:A, and all the transitions were G:C → A:T. In comparison with the surrounding sequence context of mutational base sites, the C residues in the 5'-AC(A/T)-3' sequence were found to be easily changed. Large deletions and duplications were not observed, whereas ion-induced mutations in Arabidopsis thaliana were mainly short deletions and rearrangements. The remarkable feature of yeast mutations induced by carbon ions was that the mutation sites were localized near the linker regions of nucleosomes, whereas mutations induced by γ-ray irradiation were located uniformly throughout the gene

  8. 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.

  9. Radiation-induced mitotic and meiotic aneuploidy in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Parry, J M; Sharp, D; Tippins, R S; Parry, E M

    1979-06-01

    A number of genetic systems are described which in yeast may be used to monitor the induction of chromosome aneuploidy during both mitotic and meiotic cell division. Using these systems we have been able to demonstrate the induction of both monosomic and trisomic cells in mitotically dividing cells and disomic spores in meiotically dividing cells after both UV light and X-ray exposure. The frequency of UV-light-induced monosomic colonies were reduced by post-treatment with photoreactivity light and both UV-light- and X-ray-induced monosomic colonies were reduced by liquid holding post-treatment under non-nutrient conditions. Both responses indicate an involvement of DNA-repair mechanisms in the removal of lesions which may lead to monosomy in yeast. This was further confirmed by the response of an excision-defective yeast strain which showed considerably increased sensitivity to the induction of monosomic colonies by UV-light treatment at low doses. Yeast cultures irradiated at different stages of growth showed variation in their responses to both UV-light and X-rays, cells at the exponential phase of growth show maximum sensitivity to the induction of monosomic colonies at low doses whereas stationary phase cultures showed maximum induction of monosomic colonies at high does. The frequencies of X-ray-induced chromosome aneuploidy during meiosis leading to the production of disomic spores was shown to be dependent upon the stage of meiosis at which the yeast cells were exposed to radiation. Cells which had proceeded beyond the DNA synthetic stage of meiosis were shown to produce disomic spores at considerably lower radiation doses than those cells which had only recently been inoculated into sporulation medium. The results obtained suggest that the yeast sustem may be suitable for the study of sensitivities of the various stages of meiotic cell division to the induction of chromosome aneuploidy after radiation exposure.

  10. Screening of HBsAg and anti HCV from tertiary care, private and public sector hospitals

    International Nuclear Information System (INIS)

    Khan, R.A.W.; Ahmed, W.; Alam, S.E.; Arif, A

    2011-01-01

    Objectives: To find out the frequency of hepatitis B surface antigen and hepatitis C antibodies in patients referred from a tertiary care public sector hospital, other public sector and private hospitals of Karachi. Settings and duration: Pakistan Medical Research Council's Specialized Research Centre for Gastroenterology and Hepatology, at Jinnah Postgraduate Medical Centre Karachi from January to December 2009. Patients and Methods: A cross sectional study was conducted where patients were referred from different departments of Jinnah Postgraduate Medical Centre (tertiary care public sector hospital), other public sector hospitals, private hospitals and clinics for the screening of hepatitis B and C virus infection. Three ml blood was collected from each patient, serum separated and tested for HBsAg and Anti HCV using Abbott Murex fourth Generation ELISA kits. Results: A total of 2965 cases were referred in a year. Overall sero prevalence of HBsAg and Anti-HCV was 5.9% and 12.8% respectively. HBsAg positivity in patient referred from public sector hospitals was 5.8%, those from private hospitals/clinics were 7.2%, and self-referred patients was 5.6%. Anti HCV positivity rates amongst these cases were 12.5%, 16.7% and 8.5% respectively. Co-infection of hepatitis B virus and hepatitis C virus was seen in 0.9, 2.5 and 1.4% cases respectively. Breakdown of viral positivity within different departments of Jinnah Postgraduate Medical Centre Karachi showed HBsAg positivity of 7.1% in Medical department, 5.2% in Surgical department, 5.0% in Gynaecology department, 6.6% in other departments of Jinnah Postgraduate Medical Centre while, only 1.7% were positive from Pakistan Railway, hospital Anti HCV positivity was maximally (20.3%) seen in medical department followed by 14% in other departments, 10.9% in surgical department, 7.9% in gynaecology and 5.1% in railway hospital. Co-infection of HBV and HCV was seen in 2% cases referred from medical department, while rest of the

  11. 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

  12. Degradation of lipids in yeast (Saccharomyces cerevisiae) at the early phase of organic solvent-induced autolysis

    International Nuclear Information System (INIS)

    Ishida-Ichimasa, Michiko

    1978-01-01

    Initial stage of organic solvent-induced autolysis in yeast was studied with 14 C-acetate labeled cells. In the case of toluene-induced autolysis, primary cell injury which was estimated by leakage of UV absorbing substances from cell accompanied rapid deacylation of phospholipids. Lysophospholipids did not occur during autolysis. When autolysis was induced by addition of ethyl acetate, phospholipids of yeast cells were not degraded so much. Ethyl acetate rather inhibited yeast phospholipase activity under the condition tested. (auth.)

  13. The HBsAg Prevalence Among Blood Donors From Eastern Mediterranean and Middle Eastern Countries: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Babanejad, Mehran; Izadi, Neda; Najafi, Farid; Alavian, Seyed Moayed

    2016-03-01

    The world health organization (WHO) recommends that all blood donations should be screened for evidence of infections, such as hepatitis B. The present study aimed to determine the prevalence of hepatitis B surface antigen (HBsAg) in blood donors at the eastern Mediterranean region office (EMRO) of the WHO and middle eastern countries. A meta-analysis was carried out based on the results of an electronic literature search of PubMed, Ovid, Scopus, and Google Scholar for articles published from January 1, 2000, to August 31, 2015. In accordance with a significant homogeneity test and a large value of I2, the random effects model was used to aggregate data from the studies and produce the pooled estimates using the "Metan" command. We included 66 eligible studies. The pooled prevalence of HBsAg in blood donors of both EMRO and middle eastern (E and M) countries was 2.03% (95% confidence interval [CI]: 1.79 - 2.26). In addition, the prevalence rates in the EMRO countries was 1.99% (95% CI: 1.84 - 2.14) and 1.62% in the Middle Eastern countries (95% CI: 1.36 - 1.88). The prevalence among blood donors with more than one study was 1.58% in Egypt, 0.58% in Iran, 0.67% in Iraq, 2.84% in Pakistan, 3.02% in Saudi Arabia, 1.68% in Turkey, and 5.05% in Yemen. Based on the WHO classification of hepatitis B virus (HBV) prevalence, the prevalence of HBsAg in blood donors from E and M countries reached an intermediate level. However, there were low prevalence levels in some E and M countries.

  14. Synergistic reduction of toluylene blue induced by acetaldehyde and menadione in yeast cell suspension: Application to determination of yeast cell activity

    Directory of Open Access Journals (Sweden)

    Shiro Yamashoji

    2017-03-01

    Full Text Available Membrane permeant acetaldehyde and menadione induced the synergistic reduction of toluylene blue (TB acting as non-membrane permeant redox indicator in yeast cell suspension. NADH and acetaldehyde also induced the synergistic TB reduction in permeabilized yeast cells and phosphate buffer, but menadione had no ability to promote TB reduction. The pre-incubation of acetaldehyde inhibited the above synergistic reduction of TB in intact and permeabilized yeast cell suspension. The pre-incubation of acetaldehyde might promote NADH oxidation by alcohol dehydrogenase, because acetaldehyde decreased the intracellular NAD(PH concentration. The above facts indicate that the synergistic reduction of TB is controlled by the order of addition of menadione and acetaldehyde. The synergistic reduction of TB by menadione and acetaldehyde was proportional to viable yeast cell number from 104 to 2×106 cells/ml, and this assay was applicable to cytotoxicity test. The time required for the above assay was only 2 min.

  15. Chimeric antigen receptors with human scFvs preferentially induce T cell anti-tumor activity against tumors with high B7H6 expression.

    Science.gov (United States)

    Gacerez, Albert T; Hua, Casey K; Ackerman, Margaret E; Sentman, Charles L

    2018-05-01

    B7H6 is emerging as a promising tumor antigen that is known to be expressed on a wide array of tumors and is reported to stimulate anti-tumor responses from the immune system. As such, B7H6 presents a good target for tumor-specific immunotherapies. B7H6-specific chimeric antigen receptors (CAR) based on a murine antibody showed successful targeting and elimination of tumors expressing B7H6. However, mouse single chain variable fragments (scFvs) have the potential to induce host anti-CAR responses that may limit efficacy, so human scFvs specific for B7H6 were selected by yeast surface display. In this study, we validate the functionality of these human scFvs when formatted into chimeric antigen receptors. The data indicate that T cells expressing these B7H6-specific human scFvs as CARs induced potent anti-tumor activity in vitro and in vivo against tumors expressing high amounts of B7H6. Importantly, these human scFv-based CARs are sensitive to changes in B7H6 expression which may potentially spare non-tumor cells that express B7H6 and provides the foundation for future clinical development.

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

    Science.gov (United States)

    2012-01-01

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

  17. Specificity of mutations induced by carbon ions in budding yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Matuo, Youichirou [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871 (Japan); Nishijima, Shigehiro [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871 (Japan); Hase, Yoshihiro [Radiation-Applied Biology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Watanuki-machi 1233, Takasaki, Gunma 370-1292 (Japan); Sakamoto, Ayako [Radiation-Applied Biology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Watanuki-machi 1233, Takasaki, Gunma 370-1292 (Japan); Tanaka, Atsushi [Radiation-Applied Biology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Watanuki-machi 1233, Takasaki, Gunma 370-1292 (Japan); Shimizu, Kikuo [Radioisotope Research Center, Osaka University, Yamada-oka 2-4, Suita, Osaka 565-0871 (Japan)]. E-mail: shimizu@rirc.osaka-u.ac.jp

    2006-12-01

    To investigate the nature of mutations induced by accelerated ions in eukaryotic cells, the effects of carbon-ion irradiation were compared with those of {gamma}-ray irradiation in the budding yeast Saccharomyces cerevisiae. The mutational effect and specificity of carbon-ion beams were studied in the URA3 gene of the yeast. Our experiments showed that the carbon ions generated more than 10 times the number of mutations induced by {gamma}-rays, and that the types of base changes induced by carbon ions include transversions (68.7%), transitions (13.7%) and deletions/insertions (17.6%). The transversions were mainly G:C {sup {yields}} T:A, and all the transitions were G:C {sup {yields}} A:T. In comparison with the surrounding sequence context of mutational base sites, the C residues in the 5'-AC(A/T)-3' sequence were found to be easily changed. Large deletions and duplications were not observed, whereas ion-induced mutations in Arabidopsis thaliana were mainly short deletions and rearrangements. The remarkable feature of yeast mutations induced by carbon ions was that the mutation sites were localized near the linker regions of nucleosomes, whereas mutations induced by {gamma}-ray irradiation were located uniformly throughout the gene.

  18. RTS,S/AS01E Malaria Vaccine Induces Memory and Polyfunctional T Cell Responses in a Pediatric African Phase III Trial

    Directory of Open Access Journals (Sweden)

    Gemma Moncunill

    2017-08-01

    Full Text Available Comprehensive assessment of cellular responses to the RTS,S/AS01E vaccine is needed to understand potential correlates and ultimately mechanisms of protection against malaria disease. Cellular responses recognizing the RTS,S/AS01E-containing circumsporozoite protein (CSP and Hepatitis B surface antigen (HBsAg were assessed before and 1 month after primary vaccination by intracellular cytokine staining and 16-color flow cytometry in 105 RTS,S/AS01-vaccinated and 74 rabies-vaccinated participants (controls in a pediatric phase III trial in Africa. RTS,S/AS01E-vaccinated children had significantly higher frequencies of CSP- and HBsAg-specific CD4+ T cells producing IL-2, TNF-α, and CD40L and HBsAg-specific CD4+ T producing IFN-γ and IL-17 than baseline and the control group. Vaccine-induced responses were identified in both central and effector memory (EM compartments. EM CD4+ T cells expressing IL-4 and IL-21 were detected recognizing both vaccine antigens. Consistently higher response rates to both antigens in RTS,S/AS01E-vaccinated than comparator-vaccinated children were observed. RTS,S/AS01E induced polyfunctional CSP- and HBsAg-specific CD4+ T cells, with a greater degree of polyfunctionality in HBsAg responses. In conclusion, RTS,S/AS01E vaccine induces T cells of higher functional heterogeneity and polyfunctionality than previously characterized. Responses detected in memory CD4+ T cell compartments may provide correlates of RTS,S/AS01-induced immunity and duration of protection in future correlates of immunity studies.

  19. 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.

  20. 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.

  1. A mitochondria-dependent pathway mediates the apoptosis of GSE-induced yeast.

    Directory of Open Access Journals (Sweden)

    Sishuo Cao

    Full Text Available Grapefruit seed extract (GSE, which has powerful anti-fungal activity, can induce apoptosis in S. cerevisiae. The yeast cells underwent apoptosis as determined by testing for apoptotic markers of DNA cleavage and typical chromatin condensation by Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick End Labeling (TUNEL and 4,6'-diaminidino-2-phenylindole (DAPI staining and electron microscopy. The changes of ΔΨmt (mitochondrial transmembrane potential and ROS (reactive oxygen species indicated that the mitochondria took part in the apoptotic process. Changes in this process detected by metabonomics and proteomics revealed that the yeast cells tenaciously resisted adversity. Proteins related to redox, cellular structure, membrane, energy and DNA repair were significantly increased. In this study, the relative changes in the levels of proteins and metabolites showed the tenacious resistance of yeast cells. However, GSE induced apoptosis in the yeast cells by destruction of the mitochondrial 60 S ribosomal protein, L14-A, and prevented the conversion of pantothenic acid to coenzyme A (CoA. The relationship between the proteins and metabolites was analyzed by orthogonal projections to latent structures (OPLS. We found that the changes of the metabolites and the protein changes had relevant consistency.

  2. A mitochondria-dependent pathway mediates the apoptosis of GSE-induced yeast.

    Science.gov (United States)

    Cao, Sishuo; Xu, Wentao; Zhang, Nan; Wang, Yan; Luo, YunBo; He, Xiaoyun; Huang, Kunlun

    2012-01-01

    Grapefruit seed extract (GSE), which has powerful anti-fungal activity, can induce apoptosis in S. cerevisiae. The yeast cells underwent apoptosis as determined by testing for apoptotic markers of DNA cleavage and typical chromatin condensation by Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick End Labeling (TUNEL) and 4,6'-diaminidino-2-phenylindole (DAPI) staining and electron microscopy. The changes of ΔΨmt (mitochondrial transmembrane potential) and ROS (reactive oxygen species) indicated that the mitochondria took part in the apoptotic process. Changes in this process detected by metabonomics and proteomics revealed that the yeast cells tenaciously resisted adversity. Proteins related to redox, cellular structure, membrane, energy and DNA repair were significantly increased. In this study, the relative changes in the levels of proteins and metabolites showed the tenacious resistance of yeast cells. However, GSE induced apoptosis in the yeast cells by destruction of the mitochondrial 60 S ribosomal protein, L14-A, and prevented the conversion of pantothenic acid to coenzyme A (CoA). The relationship between the proteins and metabolites was analyzed by orthogonal projections to latent structures (OPLS). We found that the changes of the metabolites and the protein changes had relevant consistency.

  3. Antigen-specific cytotoxic T cell and antigen-specific proliferating T cell clones can be induced to cytolytic activity by monoclonal antibodies against T3

    NARCIS (Netherlands)

    Spits, H.; Yssel, H.; Leeuwenberg, J.; de Vries, J. E.

    1985-01-01

    T3 is a human differentiation antigen expressed exclusively on mature T cells. In this study it is shown that anti-T3 monoclonal antibodies, in addition to their capacity to induce T cells to proliferate, are able to induce antigen-specific cytotoxic T lymphocyte clones to mediate antigen

  4. 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...

  5. Potential of high pressure homogenization to induce autolysis of wine yeasts.

    Science.gov (United States)

    Comuzzo, Piergiorgio; Calligaris, Sonia; Iacumin, Lucilla; Ginaldi, Federica; Palacios Paz, Anthony Efrain; Zironi, Roberto

    2015-10-15

    High pressure homogenization (HPH) was tested for inducing autolysis in a commercial strain of Saccharomyces bayanus for winemaking. The effects on cell viability, the release of soluble proteins, glucidic colloids and amino acids in wine-like medium and the volatile composition of the autolysates were investigated after processing, in comparison with thermolysis. HPH seemed a promising technique for inducing autolysis of wine yeasts. One pass at 150 MPa was the best operating conditions. Soluble colloids, proteins and free amino acids were similar after HPH and thermolysis, but the former gave a more interesting volatile composition after processing, with higher concentrations of ethyl esters (fruity odors) and lower fatty acids (potential off-flavors). This might allow different winemaking applications for HPH, such as the production of yeast derivatives for wine ageing. In the conditions tested, HPH did not allow the complete inactivation of yeast cells; the treatment shall be optimized before winemaking use. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. 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.

  7. Warburg effect and translocation-induced genomic instability: two yeast models for cancer cells

    International Nuclear Information System (INIS)

    Tosato, Valentina; Grüning, Nana-Maria; Breitenbach, Michael; Arnak, Remigiusz; Ralser, Markus; Bruschi, Carlo V.

    2013-01-01

    Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression (i) the activity of pyruvate kinase (PK), which recapitulates metabolic features of cancer cells, including the Warburg effect, and (ii) chromosome bridge-induced translocation (BIT) mimiking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect), and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, PK, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and post-translational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (“translocants”), between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the BIT system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

  8. Warburg effect and translocation-induced genomic instability: two yeast models for cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Tosato, Valentina [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy); Grüning, Nana-Maria [Cambridge System Biology Center, Department of Biochemistry, University of Cambridge, Cambridge (United Kingdom); Breitenbach, Michael [Division of Genetics, Department of Cell Biology, University of Salzburg, Salzburg (Austria); Arnak, Remigiusz [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy); Ralser, Markus [Cambridge System Biology Center, Department of Biochemistry, University of Cambridge, Cambridge (United Kingdom); Bruschi, Carlo V., E-mail: bruschi@icgeb.org [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy)

    2013-01-18

    Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression (i) the activity of pyruvate kinase (PK), which recapitulates metabolic features of cancer cells, including the Warburg effect, and (ii) chromosome bridge-induced translocation (BIT) mimiking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect), and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, PK, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and post-translational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (“translocants”), between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the BIT system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

  9. 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

  10. 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

  11. 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

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    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.

  12. Evaluation of HBsAg and anti-HBc assays in saliva and dried blood spot samples according HIV status.

    Science.gov (United States)

    Flores, Geane Lopes; Cruz, Helena Medina; Potsch, Denise Vigo; May, Silvia Beatriz; Brandão-Mello, Carlos Eduardo; Pires, Marcia Maria Amendola; Pilotto, Jose Henrique; Lewis-Ximenez, Lia Laura; Lampe, Elisabeth; Villar, Livia Melo

    2017-09-01

    Influence of HIV status in HBV markers detection in saliva and dried blood spots (DBS) was not well established. This study aims to evaluate the performance of optimized commercial immunoassay for identifying HBsAg and anti-HBc in saliva and DBS according HIV status. A sum of 535 individuals grouped as HIV + , HBV + , HIV/HBV + and HIV/HBV- were recruited where 347 and 188 were included for HBsAg and anti-HBc evaluation, respectively. Serum, DBS collected in Whatman 903 paper and saliva obtained using salivette device were analyzed using EIA. Increased sample volume and ROC curve analysis for cut off determination were used for DBS and saliva testing. HBsAg detection in saliva and DBS exhibited sensitivities of 80.9% and 85.6% and specificities of 86.8% and 96.3%. Sensitivity of anti-HBc in saliva and DBS were 82.4% and 76.9% and specificities in saliva and DBS were 96.9% and 91.7%. Low sensitivities were observed for HBsAg (62%) and anti-HBc (47%) detection in saliva of HIV/HBV+ individuals. OD values were also lower for HBsAg detection in DBS and saliva of HIV/HBV+ individuals compared to their serum samples. Statistical significance was found for sensitivities in HBsAg detection between saliva and DBS demonstrating high sensitivity for DBS specimens. In conclusion, HIV status or antiretroviral treatment appears to interfere in the performance of HBsAg and anti-HBc detection in DBS and saliva samples using the adapted commercial EIA. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. HBsAg seroprevalence in students for college entrance examination from 2006 to 2014 in Qidong of Jiangsu Province

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    NI Zhengping

    2015-10-01

    Full Text Available ObjectiveTo investigate the HBsAg seroprevalence in the young generation in Qidong of Jiangsu Province, China. MethodsA total of 15 534 students for college entrance examination from 2006 to 2014 were randomly selected from three secondary schools in Qidong as student group. Some of them had hepatitis B vaccination at birth. A total of 1208 adults who had their routine checkups in our hospital from 2007 to 2013 were selected as adult group. It was confirmed that all of them did not have hepatitis B vaccination at birth. Serum HBsAg levels of the two groups were measured using enzyme-linked immunosorbent assay and the seroprevalence was analyzed. Comparison of data between the two groups was made by chi-square test. Results In the 9 years from 2007 to 2013, the seroprevalence rates of HBsAg in the student group were 4.2%(75/1794, 4.3%(77/1797, 4.4%(82/1858, 4.3%(82/1903, 3.4%(56/1627, 2.6%(46/1768, 1.6%(29/1778, 1.6%(27/1642, and 1.8%(24/1367, respectively. The mean HBsAg seroprevalence of the student group was 3.2%(498/15534, significantly lower compared with 7.1% (86/1208 of the adult group (χ2= 59.986, P<0.001. In both of the student group and the adult group, the males had a significantly higher HBsAg seroprevalence than the females (χ2=10.521, P=0.001; χ2=8.452, P=0.004 and the values were 3.7%(266/7236 vs 2.8%(229/8298 and 8.8%(66/750 vs 4.4%(20/458, respectively. Among male subjects, the HBsAg seroprevalence of the adult group was 2.4 times that of the student group; among female subjects, the HBsAg seroprevalence of the adult group was 1.6 times that of the student group. ConclusionIn the recent 9 years from 2006 to 2014, the HBsAg seroprevalence in students for college entrance examination declined continuously. The goal set by the World Health Organization Western Pacific Region in 2010 had been achieved ahead of the schedule that the HBsAg seroprevalence should be controlled below 2% in children aged less than 5.

  14. 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.

  15. 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.)

  16. Frequency of anti-HCV, Hbsag and related risk factors in pregnant women at Nishtar Hospital, Multan

    International Nuclear Information System (INIS)

    Taseer, I.H.; Ishaq, F.; Hussain, L.; Safdar, S.; Mirbahar, A.M.; Faiz, S.A.

    2010-01-01

    Background: Viral hepatitis is a global issue. Among the hepatitis viruses hepatitis B and C are important in South Asia including Pakistan. There are various modes of transmission of these viruses. Vertical transmission is also gaining importance. Antepartum screening for HBV and HCV would help the infected women for appropriate antiviral therapy at appropriate time as well as for taking proper care of the newborns. The present study was designed to see the frequency of HBsAg and anti-HCV in pregnant women at Nishtar Hospital, Multan. Methods: This was a cross-sectional study carried out using non-probability purposive sampling technique. The period of the study was from June 2006 to August 2007. Five hundred (500) pregnant women attending outpatient department of Gynaecology and Obstetrics were included. Informed consent was taken. A specially designed proforma was filled in. Anti-HCV and HBsAg were tested by device method. Data were analyzed on SPSS-11. Results: Out of 500 pregnant women 35 (7.00%) were found to be anti-HCV positive and 23 (4.60%) were positive for HBsAg. Mean age was 26.7+-4.8 years. Majority of the patients 263 (52.60%) were in the age group 26-35 years. 138 (27.60%) women were nulliparous and 282 (56.40%) were para 1-4 and anti-HCV and HBsAg were common in this parity group. Only 80 (16.00%) women were para 5 or more. All anti-HCV and HBsAg positive women were house-wives. Most of them were belonging to rural areas having poor socio-economic status. Among 35 anti-HCV positive women, 20 (57.14%) had history of previous surgery, while 13 (37.14%) had history of multiple injections, 5 (14.28%) received blood transfusion, 4 (11.42%) had ear/nose piercing while tattooing was seen in only 2 (5.71%). Among 23 HBsAg positive women, 10 (43.47%) had history of previous surgery. History of multiple injections was present in 6 (26.08%) patients, 4 (17.39%) patients had history of blood transfusion, tattooing, ear/nose piercing, history of dental

  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. An investigation of clinical features of HBsAg and anti-HBs positive patients with chronic hepatitis B

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    SONG Jinyun

    2016-11-01

    Full Text Available ObjectiveTo investigate the phenomenon of coexistence of HBsAg and anti-HBs and its clinical features, as well as related causes. MethodsA total of 2260 persons who underwent physical examination in The Second Affiliated Hospital of Southeast University from February 2011 to February 2014 were enrolled, among whom 830 were diagnosed with chronic hepatitis B. Chemiluminescence microparticle immunoassay was used to screen out 188 patients with coexistence of HBsAg and anti-HBs, and these patients were divided into HBeAg positive group (101 patients and HBeAg negative group (87 patients. Another 200 patients with positive HBsAg and negative anti-HBs were enrolled as controls, among whom 80 were in the HBeAg-positive group and 120 were in the HBeAg-negative group. HBV serological markers, liver function, and viral load were measured and analyzed with reference to clinical manifestations. The chi-square test was used for comparison of categorical data between groups. ResultsThere were five patterns of HBV serological markers in patients with positive HBsAg and anti-HBs, among which positive HBsAg, anti-HBs, HBeAg, and anti-HBc and negative anti-HBe were the most common and accounted for 47.9% (90/188. The overall abnormal rate of liver function parameters was 69.1% (130/188, and the positive rate of HBV DNA was 56.9% (107/188. The two groups with positive HBeAg had a high level of HBV DNA replication, and there was no significant difference in the positive rate of HBV DNA between positive HBsAg and anti-HBs group and control group (P>0.05. In the groups with negative HBeAg, there was a significant difference in the proportion of patients with HBV DNA quantitation of >1×10^5 IU/ml between positive HBsAg and anti-HBs group and control group (P<0.05. The sequencing of the S region of HBV showed that among the 80 patients with positive HBsAg and anti-HBs, 27 had variations in this region, and the mutation rate reached 33.7%. The major variation

  19. Species specificity for HBsAg binding protein endonexin II

    NARCIS (Netherlands)

    deBruin, WCC; Leenders, WPJ; Moshage, H; vanHaelst, UJGM

    Background/Aims: Hepatitis B virus displays a distinct species and tissue tropism, Previously we have demonstrated that a human liver plasma membrane protein,vith a molecular weight of approximately 34 kiloDalton specifically binds to HBsAg. This protein was identified as endonexin II, a Ca2+

  20. Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium.

    Science.gov (United States)

    Smith, I M; Baker, A; Arneborg, N; Jespersen, L

    2015-11-01

    The human gastrointestinal epithelium makes up the largest barrier separating the body from the external environment. Whereas invasive pathogens cause epithelial barrier disruption, probiotic micro-organisms modulate tight junction regulation and improve epithelial barrier function. In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability of four nonpathogenic yeast species to modulate transepithelial electrical resistance (TER) across a monolayer of differentiated human colonocytes (Caco-2 cells). Further, we assessed yeast modulation of a Salmonella Typhimurium-induced epithelial cell barrier function insult. Our findings demonstrate distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study demonstrates distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Further, our data demonstrate significant yeast-mediated modulation of Salmonella Typhimurium-induced epithelial cell barrier disruption and identify Kluyveromyces marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study is the first to demonstrate significant non-Saccharomyces yeast

  1. PENGAMATAN SERO—VIROLOGI BEBERAPA JENIS ANTIGEN VIRUS PADA SERUM TALIPUSAT BAYI DI RS. CIPTO MANGUNKUSUMO, JAKARTA

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    Djoko Yuwono

    2012-09-01

    Full Text Available Perinatal infection due to viral agents from mother to neonate is still a major cause of viral transmis­sion in developing countries. Several type of viruses which are known to be transmitted vertieally or perinatally from mother to neonates are: Hepatitis B virus, Herpes simplex, Rubella and Cytomegalovi­rus. In attempt to estimate the real problem of viral diseases which are vertically or perinatally transmis­sible among infants, a survey on sero-virology of several type viral antigens among neonates who were borned in Dr. Cipto Mangunkusumo hospital, was carried out. A total of 227 blood samples of umbillical cord were examined for the presence of their viral anti­gens such as: Hepatitis B surface antigen (HBsAg, Herpes simplex type 1 and type 2, and anti-rubella IgM as an indicator of early infection due to rubella virus in the fetus. The detection of antigens and anti-rubella IgM in the serum.were done by ELISA methode using reagents which are commercially available. The result of the study indicated that there was a possibility of perinatal infection due to related viruses, i.e.: 2.2%; 1.9% and 14.3% due to HBsAg; Herpes simplex type 1 and type 2 respectivelly, however none of the serum indicated seropositive IgM against rubella virus: infection.

  2. 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)

  3. 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.

  4. Value of HBsAg level in dynamic monitoring of disease progression in patients with chronic HBV infection

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    BAO Teng

    2017-08-01

    Full Text Available ObjectiveTo investigate the clinical value of HBsAg level in dynamic monitoring of disease progression in patients with chronic HBV infection. MethodsA retrospective analysis was performed for the clinical data of 1107 patients with different clinical stages of chronic HBV infection who had not received antiviral therapy at the time of hospitalization in The Second Affiliated Hospital of Anhui Medical University from May 2011 to December 2015, and according to the disease status, they were divided into HBeAg-positive chronic hepatitis B (CHB group, HBeAg-negative CHB group, compensated liver cirrhosis group (LC-C group, decompensated liver cirrhosis group (LC-D group, and primary liver cancer (PLC group. These groups were compared in terms of HBsAg expression and the association between HBsAg and clinical features. An analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t-test was used for further comparison between any two groups; the t-test was used for comparison of continuous data between two groups. The chi-square test was used for comparison of categorical data between these groups. Pearson correlation analysis was also performed. ResultsThere was a significant difference in serum HBsAg level between the HBeAg-positive CHB group, HBeAg-negative CHB group, LC-C group, LC-D group, and PLC group (F=100.45, P<0.001. The HBeAg-positive CHB group had significantly higher levels of HBsAg and HBV DNA than the HBeAg-negative CHB group (t= 16.67 an 16.22, both P<0.001. There were significant differences in HBsAg and HBV DNA levels between the HBeAg-positive CHB group, LC-C group, LC-D group, and PLC group (F= 42.92 and 27.38, both P<0.001, as well as between the HBeAg-negative CHB group, LC-C group, LC-D group, and PLC group (F=6.04 and 4.10, both P<0.05. HBV DNA level was significantly different across patients with different HBsAg levels (<1000 IU/ml, 1000-20 000 IU

  5. Results of HBsAg examination with immunoelectrophoresis and radioimmunoassay in VPR, Laotian PDR and Cuban R

    Energy Technology Data Exchange (ETDEWEB)

    Michal, L; Szilagyiova, M; Zahradny, V; Holan, J; Krajnak, V [Komenskeho Univ., Martin (Czechoslovakia). Lekarska Fakulta; Padurova, J [Okresna Hygienicka Stanica, Zilina (Czechoslovakia)

    1984-06-21

    The results are compared of examining 112 Vietnamese, 30 Laotian and 50 Cuban citizens for HBsAg using IEP and RIA methods. Of the examined persons with no liver disorders HBsAg was found in 23 (31.5%) of the Vietnamese and 1 (2.5%) of the Cubans using the RIA method and only in 4 (5.5%) of the Vietnamese using the IEP method. Of the examined persons with liver disorders RIA found HBsAg in 12 (30.8%) of the Vietnamese, 5 (71.4%) of the Laotians and 2 (20.0%) of the Cubans while with IEP only in 3 (7.7%) Vietnamese 2 (28.6%) Laotians and 1 (10.0%) of the Cubans examined.

  6. Results of HBsAg examination with immunoelectrophoresis a radioimmunoassay in VPR, Laotian PDR and Cuban R

    International Nuclear Information System (INIS)

    Michal, L.; Szilagyiova, M.; Zahradny, V.; Holan, J.; Krajnak, V.

    1984-01-01

    The results are compared of examining 112 Vietnamese, 30 Laotian and 50 Cuban citizens for HBsAg using IEP and RIA methods. Of the examined persons with no liver disorders HBsAg was found in 23 (31.5%) of the Vietnamese and 1 (2.5%) of the Cubans using the RIA method and only in 4 (5.5%) of the Vietnamese using the IEP method. Of the examined persons with liver disorders RIA found HBsAg in 12 (30.8%) of the Vietnamese, 5 (71.4%) of the Laotians and 2 (20.0%) of the Cubans while with IEP only in 3 (7.7%) Vietnamese 2 (28.6%) Laotians and 1 (10.0%) of the Cubans examined. (author)

  7. [Predictive study of HBsAg in different stages of neonatal venous blood on failure of blocking HBV mother to infant transmission].

    Science.gov (United States)

    Yi, Wei; Li, Ming-Hui; Hu, Yu-Hong; Liu, Feng; Zhang, Yang-Li; Liu, Xue-Jing; Hao, Hong-Xiao; Song, Shu-Jing; Liu, Ying; Li, Xing-Hong; Sun, Ji-Yun; Liu, Min; Cheng, Jun; Xie, Yao

    2011-10-01

    In this study, we discuss the predictive value of different content of HBsAg in different stages of neotal venous blood on failure of blocking mother to infant transmission of HBV. 150 infants born of chronically HBV infected mothers who were positive of both HBsAg and HBeAg and who also had a HBV DNA virus load above 10(5) copies/ml were enrolled. These infants were given hepatitis B virus immune globin (HBIG) 200 IU immediately after birth and were given hepatitis B vaccine 10 or 20 microg at brith, 1 month and 6 months after birth. HBV serological index of these infants were test at birth, 1 month and 7 months after birth respectively. Different content of HBsAg in different stages of neonatal venus blood were analyzed to predict the failure of blocking mother to infant transmission of HBV. 11 infants failed in blocking of HBV mother to infant transmission. The positive rate of HBsAg at birth, 1 month and 7 months after birth were 41.26%, 10.49% and 7.69% respectively, and were 97.90%, 65.73% and 13.29% of HBeAg. The positive predictive value of HBsAg > or = 0.05 and HBsAg > or = 1 IU/ml at birth were 18.64% and 70% respectively, and were 73.33% and 100% one month after birth. Infants with HBsAg > or = 1 IU/ml at birth should be suspicious of failure on blocking HBV mother-to-infant transmission and it should be more credible if the infant has HBsAg > or = 1 IU/ml one month after birth. How to improve the blocking rate of neonates who were positive of HBsAg at birth and one month after birth should be the focus of our future research.

  8. [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.

  9. Adjuvant Activity of Poly-ε-caprolactone/Chitosan Nanoparticles Characterized by Mast Cell Activation and IFN-γ and IL-17 Production.

    Science.gov (United States)

    Jesus, Sandra; Soares, Edna; Borchard, Gerrit; Borges, Olga

    2018-01-02

    Polymeric nanoparticles (NPs) are extremely attractive vaccine adjuvants, able to promote antigen delivery and in some instances, exert intrinsic immunostimulatory properties that enhance antigen specific humoral and cellular immune responses. The poly-ε-caprolactone (PCL)/chitosan NPs were designed with the aim of being able to combine the properties of the 2 polymers in the preparation of an adjuvant for the hepatitis B surface antigen (HBsAg). This article reports important results of an in vitro mechanistic study and immunization studies with HBsAg associated with different concentrations of the nanoparticles. The results revealed that PCL/chitosan NPs promoted mast cell (MC) activation (β-hexosaminidase release) and that its adjuvant effect is not mediated by the TNF-α secretion. Moreover, we demonstrated that HBsAg loaded PCL/chitosan NPs, administered through the subcutaneous (SC) route, were able to induce higher specific antibody titers without increasing IgE when compared to a commercial vaccine, and that the IgG titers are nanoparticle-dose dependent. The results also revealed the NPs' capability to promote a cellular immune response against HBsAg, characterized by the production of IFN-γ and IL-17. These results demonstrated that PCL/chitosan NPs are a good hepatitis B antigen adjuvant, with direct influence on the intensity and type of the immune response generated.

  10. An IPTG-inducible derivative of the fission yeast nmt promoter

    DEFF Research Database (Denmark)

    Kjærulff, Søren; Nielsen, Olaf

    2015-01-01

    We here describe an IPTG-inducible system that reveals that the lac repressor alone can function as a potent transmodulator to regulate gene expression in the fission yeast, Schizosaccharomyces pombe. This expression system is a derivative of the Sz. pombe nmt promoter, which normally is strongly...

  11. 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.

  12. Generation and characterization of antigenic variants induced by exposure of tumor cells to UV radiation in vitro

    International Nuclear Information System (INIS)

    Hostetler, L.L.W.

    1988-01-01

    Antigenic changes present in nonantigenic tumor cells exposed to UV radiation (UV) in vitro were investigated by addressing the following questions: (1) Are antigenic variants (AV) produced that are rejected in normal but not immunosuppressed mice? (2) Does generation of AV depend upon intrinsic properties of the cells exposed or result from the action of UV? (3) Is antigenic modification induced by UV due to increased histocompatibility antigen expression? (4) Do AV crossreact immunologically with parental tumor or with other AV? and (5) Is the UV-associated common antigen expressed on UV-induced tumors present on UV-irradiated tumor cells? AV were generated at different frequencies following in vitro UV irradiation of a spontaneous murine fibrosarcoma, a murine melanoma, and two melanoma clones. Immunological experiments demonstrated that the AV and parental cells shared a determinant that was susceptible to immune recognition, but incapable of inducing immunity. In contrast, the AV were noncrossreactive, suggesting that variant-specific antigens were also expressed. Finally, the AV were recognized by UV-induced suppressor cells, indicating that the UV-associated common antigen expressed by UV-induced tumors was also present

  13. Helminth antigens counteract a rapid high-fat diet-induced decrease in adipose tissue eosinophils.

    Science.gov (United States)

    van den Berg, Susan M; van Dam, Andrea D; Kusters, Pascal J H; Beckers, Linda; den Toom, Myrthe; van der Velden, Saskia; Van den Bossche, Jan; van Die, Irma; Boon, Mariëtte R; Rensen, Patrick C N; Lutgens, Esther; de Winther, Menno P J

    2017-10-01

    Brown adipose tissue (BAT) activation and white adipose tissue (WAT) beiging can increase energy expenditure and have the potential to reduce obesity and associated diseases. The immune system is a potential target in mediating brown and beige adipocyte activation. Type 2 and anti-inflammatory immune cells contribute to metabolic homeostasis within lean WAT, with a prominent role for eosinophils and interleukin (IL)-4-induced anti-inflammatory macrophages. We determined eosinophil numbers in epididymal WAT (EpAT), subcutaneous WAT (ScAT) and BAT after 1 day, 3 days or 1 week of high-fat diet (HFD) feeding in C57Bl/6 mice. One day of HFD resulted in a rapid drop in eosinophil numbers in EpAT and BAT, and after 3 days, in ScAT. In an attempt to restore this HFD-induced drop in adipose tissue eosinophils, we treated 1-week HFD-fed mice with helminth antigens from Schistosoma mansoni or Trichuris suis and evaluated whether the well-known protective metabolic effects of helminth antigens involves BAT activation or beiging. Indeed, antigens of both helminth species induced high numbers of eosinophils in EpAT, but failed to induce beiging. In ScAT, Schistosoma mansoni antigens induced mild eosinophilia, which was accompanied by slightly more beiging. No effects were observed in BAT. To study type 2 responses on brown adipocytes directly, T37i cells were stimulated with IL-4. This increased Ucp1 expression and strongly induced the production of eosinophil chemoattractant CCL11 (+26-fold), revealing that brown adipocytes themselves can attract eosinophils. Our findings indicate that helminth antigen-induced eosinophilia fails to induce profound beiging of white adipocytes. © 2017 Society for Endocrinology.

  14. Serologic tracers (HBsAg and HBsAc) of hepatitis B virus in expectant mothers of the Perinatal Maternal Institute; Marcadores serologicos (HBsAg y HBsAc) del virus de la hepatitis B en mujeres gestantes del Instituto Materno Perinatal

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, B M

    1997-07-01

    A study on hepatitis B tracers, (HBsAg and HBsAc), was conducted in women with different months of pregnancy at the Perinatal Maternal Institute in Lima, Peru. A total of 1010 mothers were studied during the period of January to October 1996, establishing by radioimmunoassay (RIA) whether they were positive or not. The results showed a prevalence rate of 1,6 for HBsAc and 1,3 for HBsAg for every 100,000 inhabitants. The incidence rate was 0,332 for HBsAc and 0,07 for HBsAg for every 100,000 inhabitants. This means that 21 expectant mothers are HBsAc positive and 5 are HBsAg positive. According to the investigations, there were different ways of transmission; promiscuity must be highlighted, as well as age -most of the mothers who were positive were between 20 and 25 years old- and origin. Most of them were immigrants from different places and live in shantytowns, which indicates that most of them have limited economic resources and have not received any orientation on family planning.

  15. Anti-pre-S responses and viral clearance in chronic hepatitis B virus infection.

    Science.gov (United States)

    Budkowska, A; Dubreuil, P; Poynard, T; Marcellin, P; Loriot, M A; Maillard, P; Pillot, J

    1992-01-01

    Serial sera were collected prospectively during the clinical course of 13 HBsAg carriers with chronic liver disease and analyzed for ALT levels, pre-S1 and pre-S2 antigens and corresponding antibodies and other serological hepatitis B virus markers. In five patients, anti-pre-S1 and anti-pre-S2 antibodies became detectable in multiple serum samples, whereas in eight patients anti-pre-S was never detected or only appeared transiently during the follow-up. The first pattern was associated with normalization of ALT levels and undetectable pre-S antigens and viral DNA by the polymerase chain reaction assay at final follow-up. HBsAg clearance occurred in two of the five patients. The second pattern was one of persistence of HBsAg and pre-S antigens, associated with the presence of serum HBV DNA detectable by spot hybridization or polymerase chain reaction regardless of clinical outcome. These findings demonstrate the occurrence of anti-pre-S antibodies in chronic hepatitis B virus-induced liver disease and associate anti-pre-S appearance with the clearance of hepatitis B virus from serum.

  16. Effect of Brewer's Yeast-Induced Pyrexia on Aminophylline-Elicited Convulsions in Mice

    OpenAIRE

    Ochi, Rika; Suemaru, Katsuya; Kawasaki, Hiromu; Araki, Hiroaki

    2009-01-01

    Theophylline-associated convulsions have been observed most frequently in children with fever, but the mechanism is not fully understood. In this study, we investigated the basic mechanism of aminophylline [theophylline-2-ethylenediamine]-induced convulsions and the effects of Brewer's yeast-induced pyrexia in mice. Diazepam (5-10mg/kg, i.p.), a benzodiazepine receptor agonist, significantly prolonged the onset and significantly decreased the incidence of convulsions induced by aminophylline ...

  17. Polyglutamine toxicity in yeast induces metabolic alterations and mitochondrial defects

    KAUST Repository

    Papsdorf, Katharina

    2015-09-03

    Background Protein aggregation and its pathological effects are the major cause of several neurodegenerative diseases. In Huntington’s disease an elongated stretch of polyglutamines within the protein Huntingtin leads to increased aggregation propensity. This induces cellular defects, culminating in neuronal loss, but the connection between aggregation and toxicity remains to be established. Results To uncover cellular pathways relevant for intoxication we used genome-wide analyses in a yeast model system and identify fourteen genes that, if deleted, result in higher polyglutamine toxicity. Several of these genes, like UGO1, ATP15 and NFU1 encode mitochondrial proteins, implying that a challenged mitochondrial system may become dysfunctional during polyglutamine intoxication. We further employed microarrays to decipher the transcriptional response upon polyglutamine intoxication, which exposes an upregulation of genes involved in sulfur and iron metabolism and mitochondrial Fe-S cluster formation. Indeed, we find that in vivo iron concentrations are misbalanced and observe a reduction in the activity of the prominent Fe-S cluster containing protein aconitase. Like in other yeast strains with impaired mitochondria, non-fermentative growth is impossible after intoxication with the polyglutamine protein. NMR-based metabolic analyses reveal that mitochondrial metabolism is reduced, leading to accumulation of metabolic intermediates in polyglutamine-intoxicated cells. Conclusion These data show that damages to the mitochondrial system occur in polyglutamine intoxicated yeast cells and suggest an intricate connection between polyglutamine-induced toxicity, mitochondrial functionality and iron homeostasis in this model system.

  18. Detection of viral antigens by solid phase radioimmunoassay on polyethylene film

    Energy Technology Data Exchange (ETDEWEB)

    Prokudina, E N; Semenova, N P; Zhdanov, V M

    1986-04-01

    Polyethylene film, without any pretreatment, may serve as a solid phase (SP) for RIA. Viral antigens (HBsAg, and influenza virus) are detected by SP-RIA on the film with a sensitivity of about 2-3 ng/ml or 40-60 pg/assay. The use of polyethylene film allows one to record RIA autographically. The use of micro amounts of reagents and specimens tested is an added advantage. No special equipment is necessary, the method is inexpensive, easy to perform and may be used for mass screening. (Auth.). 7 refs.; 4 figs.

  19. A novel chromosome region maintenance 1-independent nuclear export signal of the large form of hepatitis delta antigen that is required for the viral assembly.

    Science.gov (United States)

    Lee, C H; Chang, S C; Wu, C H; Chang, M F

    2001-03-16

    Hepatitis delta virus (HDV) is a satellite virus of hepatitis B virus, as it requires hepatitis B virus for virion production and transmission. We have previously demonstrated that sequences within the C-terminal 19-amino acid domain flanking the isoprenylation motif of the large hepatitis delta antigen (HDAg-L) are important for virion assembly. In this study, site-directed mutagenesis and immunofluorescence staining demonstrated that in the absence of hepatitis B virus surface antigen (HBsAg), the wild-type HDAg-L was localized in the nuclei of transfected COS7 cells. Nevertheless, in the presence of HBsAg, the HDAg-L became both nuclei- and cytoplasm-distributed in about half of the cells. An HDAg-L mutant with a substitution of Pro-205 to alanine could neither form HDV-like particles nor shift the subcellular localization in the presence of HBsAg. In addition, nuclear trafficking of HDAg-L in heterokaryons indicated that HDAg-L is a nucleocytoplasmic shuttling protein. A proline-rich HDAg peptide spanning amino acid residues 198 to 210, designated NES(HDAg-L), can function as a nuclear export signal (NES) in Xenopus oocytes. Pro-205 is critical for the NES function. Furthermore, assembly of HDV is insensitive to leptomycin B, indicating that the NES(HDAg-L) directs nuclear export of HDAg-L to the cytoplasm via a chromosome region maintenance 1-independent pathway.

  20. 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...

  1. Immunizations with hepatitis B viral antigens and a TLR7/8 agonist adjuvant induce antigen-specific immune responses in HBV-transgenic mice

    Directory of Open Access Journals (Sweden)

    Ying Wang

    2014-12-01

    Conclusions: Immunization with CL097-conjugated HBV-Ag reversed immune tolerance in HBV-Tg mice and induced antigen-specific immune responses. TLR7/8 agonists appear to be potent adjuvants for the induction of antigen-specific Th1 responses in an immune tolerant state.

  2. 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

  3. Inherent and antigen-induced airway hyperreactivity in NC mice

    Directory of Open Access Journals (Sweden)

    Tetsuto Kobayashi

    1999-01-01

    Full Text Available In order to clarify the airway physiology of NC mice, the following experiments were carried out. To investigate inherent airway reactivity, we compared tracheal reactivity to various chemical mediators in NC, BALB/c, C57BL/6 and A/J mice in vitro. NC mice showed significantly greater reactivity to acetylcholine than BALB/c and C57BL/6 mice and a reactivity comparable to that of A/J mice, which are known as high responders. Then, airway reactivity to acetylcholine was investigated in those strains in vivo. NC mice again showed comparable airway reactivity to that seen in A/J mice and a significantly greater reactivity than that seen in BALB/c and C57BL/6 mice. To investigate the effects of airway inflammation on airway reactivity to acetylcholine in vivo, NC and BALB/c mice were sensitized to and challenged with antigen. Sensitization to and challenge with antigen induced accumulation of inflammatory cells, especially eosinophils, in lung and increased airway reactivity in NC and BALB/c mice. These results indicate that NC mice exhibit inherent and antigen-induced airway hyperreactivity. Therefore, NC mice are a suitable strain to use in investigating the mechanisms underlying airway hyperreactivity and such studies will provide beneficial information for understanding the pathophysiology of asthma.

  4. A new model mimicking persistent HBV e antigen-negative infection using covalently closed circular DNA in immunocompetent mice.

    Directory of Open Access Journals (Sweden)

    Lei Wang

    Full Text Available Despite the availability of an effective vaccine, hepatitis B virus (HBV infection remains a major health problem. HBV e antigen (HBeAg-negative strains have become prevalent. Previously, no animal model mimicked the clinical course of HBeAg-negative HBV infection. To establish an HBeAg-negative HBV infection model, the 3.2-kb full-length genome of HBeAg-negative HBV was cloned from a clinical sample and then circularized to form covalently closed circular (cccDNA. The resulting cccDNA was introduced into the liver of C57BL/6J mice through hydrodynamic injection. Persistence of the HBeAg-negative infection was monitored at predetermined time points using HBV-specific markers including HBV surface antigen (HBsAg, HBeAg, and HBV core antigen (HBcAg as well as DNA copies. Throughout the study, pAAV-HBV1.2 was used as a control. In mice injected with HBeAg-negative cccDNA, the HBV infection rate was 100% at the initial stage. HBsAg levels increased up to 1 week, at which point levels peaked and dropped quickly thereafter. In 60% of injected mice, HBsAg and HBcAg persisted for more than 10 weeks. High numbers of HBV DNA copies were detected in the serum and liver. Moreover, cccDNA persisted in the liver tissue of HBeAg-negative mice. In contrast to the pAAV-HBV 1.2 injected mice, no HBeAg was found in mice injected with HBeAg-negative HBV throughout the study period. These results demonstrate the first successful establishment of a model of HBeAg-negative HBV-persistent infection in immunocompetent mice. Compared to pAAV-HBV1.2-injected mice, the infection persistence and levels of serum virological and biochemical markers were approximately equal in the model mice. This model will be useful for mechanistic studies on HBeAg-negative HBV infection and will facilitate the evaluation of new antiviral drugs.

  5. Monoclonal antibodies reactive with common tumor antigens on UV-induced tumors also react with hyperplastic UV-irradiated skin

    International Nuclear Information System (INIS)

    Spellman, C.W.; Beauchamp, D.A.

    1986-01-01

    Most murine skin tumors induced by ultraviolet light (UVB, 280-340 nm) can be successfully transplanted only into syngeneic hosts that have received subcarcinogenic doses of UVB. The tumor susceptible state is long-lived and mediated by T suppressor cells that control effector responses against common antigens on UV-induced tumors. Because antigen specific suppression arises prior to the appearance of a tumor, questions arise about the source of the original antigen. They have previously reported transplantation studies indicating that UV-irradiated skin is antigenically cross-reactive with UV-induced tumors. They now report on flow cytometry analyses showing that a series of MoAb reactive with common antigens expressed by UV-induced tumors are also reactive on cells from UV-irradiated skin. Various antigens appear at different times in the UV irradiation scheme, and some persist while others are transient. They speculate that the common antigens detected may be the ones to which functional suppression is directed. If true, these results suggest that successful tumors need not escape host defenses to emerge. Rather, tumors may arise and grow progressively if they express antigens that cross-react with specificities to which the host has previously mounted a suppressive response

  6. Yeast Interacting Proteins Database: YFR015C, YFR015C [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entr...ression induced by glucose limitation, nitrogen starvation, environmental stress, and entry into stationary ...tion, nitrogen starvation, environmental stress, and entry into stationary phase Rows with this bait as bait..., the more highly expressed yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental

  7. The influence of sterol metabolism upon radiation-induced aneuploidy of Drosophila melanogaster in the yeast-drosophila system

    International Nuclear Information System (INIS)

    Savitsij, V.V.; Luchnikova, E.M.; Inge-Vechtomov, S.I.

    1985-01-01

    The influence of sterol metabolism upon induced Drosophila melanogaster mutagenesis in an ecology-genetic yeast-drosophila system has been studied. The sterol deficit in fly organism has been created for account of using as food substrate for fremales of biomass of saccharomyces cerevisiae living cells of 9-2-PZ12 train with nyssup(r1) locus mutation which blocks the ergosterol synthesis. It has been found that the Drosophila females content on mutant yeast increases the frequency of losses and non discrepancy of X-chromosomes induced by X-radiation (1000 R). Addition into yeast biomass of 0.1 % cholesterol solution in 10 %-ethanol reduces the oocytes resistance to X-radiation up to control level. Possible hormonal and membrane mechanisms of increasing radiation-induced aneuploidy of Drosophila and the role of sterol metabolism in organism resistance to damaging factors are discussed

  8. Yeast CUP1 protects HeLa cells against copper-induced stress

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X.X. [Department of Animal Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai (China); Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai (China); College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou (China); Ma, Y.F.; Wang, Q.S.; Chen, Z.L.; Liao, R.R.; Pan, Y.C. [Department of Animal Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai (China); Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai (China)

    2015-06-12

    As an essential trace element, copper can be toxic in mammalian cells when present in excess. Metallothioneins (MTs) are small, cysteine-rich proteins that avidly bind copper and thus play an important role in detoxification. YeastCUP1 is a member of the MT gene family. The aim of this study was to determine whether yeast CUP1 could bind copper effectively and protect cells against copper stress. In this study,CUP1 expression was determined by quantitative real-time PCR, and copper content was detected by inductively coupled plasma mass spectrometry. Production of intracellular reactive oxygen species (ROS) was evaluated using the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay. Cellular viability was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the cell cycle distribution of CUP1 was analyzed by fluorescence-activated cell sorting. The data indicated that overexpression of yeast CUP1 in HeLa cells played a protective role against copper-induced stress, leading to increased cellular viability (P<0.05) and decreased ROS production (P<0.05). It was also observed that overexpression of yeast CUP1 reduced the percentage of G1 cells and increased the percentage of S cells, which suggested that it contributed to cell viability. We found that overexpression of yeast CUP1 protected HeLa cells against copper stress. These results offer useful data to elucidate the mechanism of the MT gene on copper metabolism in mammalian cells.

  9. Biomedical applications of yeast- a patent view, part one: yeasts as workhorses for the production of therapeutics and vaccines.

    Science.gov (United States)

    Roohvand, Farzin; Shokri, Mehdi; Abdollahpour-Alitappeh, Meghdad; Ehsani, Parastoo

    2017-08-01

    Yeasts, as Eukaryotes, offer unique features for ease of growth and genetic manipulation possibilities, making it an exceptional microbial host. Areas covered: This review provides general and patent-oriented insights into production of biopharmaceuticals by yeasts. Patents, wherever possible, were correlated to the original or review articles. The review describes applications of major GRAS (generally regarded as safe) yeasts for the production of therapeutic proteins and subunit vaccines; additionally, immunomodulatory properties of yeast cell wall components were reviewed for use of whole yeast cells as a new vaccine platform. The second part of the review will discuss yeast- humanization strategies and innovative applications. Expert opinion: Biomedical applications of yeasts were initiated by utilization of Saccharomyces cerevisiae, for production of leavened (fermented) products, and advanced to serve to produce biopharmaceuticals. Higher biomass production and expression/secretion yields, more similarity of glycosylation patterns to mammals and possibility of host-improvement strategies through application of synthetic biology might enhance selection of Pichia pastoris (instead of S. cerevisiae) as a host for production of biopharmaceutical in future. Immunomodulatory properties of yeast cell wall β-glucans and possibility of intracellular expression of heterologous pathogen/tumor antigens in yeast cells have expanded their application as a new platform, 'Whole Yeast Vaccines'.

  10. Seropositivity of HBsAg, anti-HCV and anti-HIV in preoperative patients

    Directory of Open Access Journals (Sweden)

    Berrin Karaayak Uzun

    2014-12-01

    Full Text Available Objective: The infections caused by human immunodeficiency virus (HIV, hepatitis B (HBV and C (HCV viruses pose a serious occupational risk for the healthcare workers especially those in emergency services, laboratories and surgery wards. Vaccination and establishment of the strict biosafety procedures are the main principles to prevent blood-borne infections in healthcare workers. Additionally, serological screening of the preoperative patients could decrease the risk for exposure. In this study, we aimed to determine the seroprevalence of HBsAg, anti-HCV, anti-HIV 1/2 in preoperative patients. Methods: Hospital automation records were evaluated retrospectively for 4.367 patients who were scheduled for surgery and scanned for anti-HIV 1/2, HBsAg and anti-HCV as preoperative procedures in the preparation period of operation between January 2012 and December 2012. Results: HBsAg positivity rate was found in 7.7% (n=336, anti-HCV positivity rate was found in 2.3% (n=101. A two (0.05% of five patients were positive for anti-HIV 1/2 was found positive verification test and the other three samples were accepted as false positive test results. Conclusion: All healthcare workers must be trained about occupational diseases and vaccinated against Hepatitis B. Universal precautions must be strictly followed particularly in the operating room. In addition, all patients should be considered as potential carriers regarded as a carrier of the potential for infection. J Clin Exp Invest 2013; 4 (4: 449-452

  11. Immobilization of yeast cells on hydrogel carriers obtained by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Luzhao Xin; Carenza, M.; Kaetsu, Isao; Kumakura, Minoru; Yoshida, Masaru; Fujimura, Takashi

    1992-01-01

    Polymer hydrogels were obtained by radiation-induced copolymerization at -78 o C of aqueous solutions of acrylic and methacrylic esters. The matrices were characterized by equilibrium water content measurements, by optical microscopy observations and by scanning electron microscopy analysis. Yeast cells were immobilized on these hydrogels and the ethanol productivity by batch fermentation was determined. Matrix hydrophilicity and porosity were found to deeply influence the adhesion of yeast cells and, hence, the ethanol productivity. The latter as well as other physico-chemical properties were also affected by the presence of a crosslinking agent added in small amounts to the polymerizating mixture. (author)

  12. Effect of dimethyl sulfoxide (DMSO) on radiation-induced heteroallelic reversion in diploid yeast

    International Nuclear Information System (INIS)

    Singh, D.R.; Mahajan, J.M.; Krishnan, D.

    1976-01-01

    Dimethyl sulfoxide has cryoprotective and radioprotective properties. It is also an efficient scavenger of radicals produced by radiolysis of water. Gamma-induced reversion of diploid yeast in the presence of this chemical during irradiation have been studied. The dose-modifying factor was in the same range as for survival. When the yeast was irradiated in the frozen state, the observed protection by DMSO disappeared. The results are discussed in terms of direct and indirect actions of radiations and the radical-scavenging ability of this chemical

  13. Protective effect of Brewer's yeast on methimazole-induced-adrenal atrophy (a stereological study).

    Science.gov (United States)

    Dehghani, Farzaneh; Zabolizadeh, Jamal; Noorafshan, Ali; Panjehshahin, Mohammad Reza; Karbalay-Doust, Saied

    2010-04-20

    Induction of hypothyroidism by thioamide drugs will cause adrenal gland atrophy and decrease in its hormones. To prevent side effect on the adrenal gland, brewer's yeast, a natural product rich in vitamins and minerals was used. Serological techniques were applied to measure the volume of adrenal gland. For this purpose, 48 Sprague-Dawley rats were randomly divided into one control and three experimental groups. In group 1, methimazole was administered at the dose of 30 mg/kg/day days, in group 2, 120 mg/kg/day of, brewer's yeast, in group 3, 30 mg/kg/day of methimazole plus 120 mg/kg/day of brewer yeast, and for the control group, an equal volume of saline (0.5 ml/rat/day) was orally given. After 30 days, all the animals were anesthetized and their adrenal glands were removed, fixed, embedded and stained. The volume of different zones of the adrenal glands was estimated by Cavalieri principle and point counting methods. statistical analysis was performed using Mann-Withney test and p Brewer's yeast reduced the methimazole side effects on this zone. In conclusion, it seems that the use of brewer's yeast could prevent methimazole-induced atrophy of the adrenal gland.

  14. Estradiol-induced vaginal mucus inhibits antigen penetration and CD8(+) T cell priming in response to intravaginal immunization.

    Science.gov (United States)

    Seavey, Matthew M; Mosmann, Tim R

    2009-04-14

    Although vaginal immunization has been explored as a strategy to induce mucosal immunity in the female reproductive tract, this site displays unique immunological features that probably evolved to inhibit anti-paternal T cell responses after insemination to allow successful pregnancy. We previously demonstrated that estradiol, which induces an estrus-like state, prevented CD8(+) T cell priming during intravaginal immunization of mice. We now show that estradiol prevented antigen loading of vaginal antigen presenting cells (APCs) after intravaginal immunization. Histological examination confirmed that estradiol prevented penetration of peptide antigen into the vaginal wall. Removal of the estradiol-induced mucus barrier by mucinase partially restored antigen loading of vaginal APC and CD8(+) T cell proliferation in vivo. The estradiol-induced mucus barrier may thus prevent exposure to antigens delivered intravaginally, supplementing additional estradiol-dependent mechanism(s) that inhibit CD8(+) T cell priming after insemination or vaginal vaccination.

  15. Estradiol-induced vaginal mucus inhibits antigen penetration and CD8+ T cell priming in response to intravaginal immunization

    Science.gov (United States)

    Seavey, Matthew M.; Mosmann, Tim R.

    2010-01-01

    Although vaginal immunization has been explored as a strategy to induce mucosal immunity in the female reproductive tract, this site displays unique immunological features that probably evolved to inhibit anti-paternal T cell responses after insemination to allow successful pregnancy. We previously demonstrated that estradiol, which induces an estrus-like state, prevented CD8+ T cell priming during intravaginal immunization of mice. We now show that estradiol prevented antigen loading of vaginal antigen presenting cells (APC) after intravaginal immunization. Histological examination confirmed that estradiol prevented penetration of peptide antigen into the vaginal wall. Removal of the estradiol-induced mucus barrier by mucinase partially restored antigen loading of vaginal APC and CD8+ T cell proliferation in vivo. The estradiol-induced mucus barrier may thus prevent exposure to antigens delivered intravaginally, supplementing additional estradiol-dependent mechanism(s) that inhibit CD8+ T cell priming after insemination or vaginal vaccination. PMID:19428849

  16. Serologic tracers (HBsAg and HBsAc) of hepatitis B virus in expectant mothers of the Perinatal Maternal Institute

    International Nuclear Information System (INIS)

    Garcia G, B.M.

    1997-01-01

    A study on hepatitis B tracers, (HBsAg and HBsAc), was conducted in women with different months of pregnancy at the Perinatal Maternal Institute in Lima, Peru. A total of 1010 mothers were studied during the period of January to October 1996, establishing by radioimmunoassay (RIA) whether they were positive or not. The results showed a prevalence rate of 1,6 for HBsAc and 1,3 for HBsAg for every 100,000 inhabitants. The incidence rate was 0,332 for HBsAc and 0,07 for HBsAg for every 100,000 inhabitants. This means that 21 expectant mothers are HBsAc positive and 5 are HBsAg positive. According to the investigations, there were different ways of transmission; promiscuity must be highlighted, as well as age -most of the mothers who were positive were between 20 and 25 years old- and origin. Most of them were immigrants from different places and live in shantytowns, which indicates that most of them have limited economic resources and have not received any orientation on family planning

  17. Repair of 313-nm induced lesions and photoprotection in yeast Candida guilliermondii

    International Nuclear Information System (INIS)

    Fraikin, G.Y.; Pospelov, M.E.; Rubin, L.B.

    1977-01-01

    The present communication is concerned with the effects of near-UV radiation (300-380 nm) on yeast Candida guilliermondii. It was found that certain doses of 313 nm irradiation caused inactivation of the yeast which was exhibited in a way different from the lethal action of far-UV radiation. It was also found that the cells inactivated by 313 nm are capable of recovering vitality, if incubated for some time in a non-nutrient medium. The yeast inactivated by far-UV radiation also proved to be capable of recovering, though to a lesser degree. Both 334 nm radiation and non-lethal doses at 313 nm induced the photoprotective effect against far-UV damage. The effect was exhibited if there was a certain time interval (2-4 h) between the exposures to photoprotective light and subsequent far-UV radiation. Within this time interval the extent of photoprotection was dependent on temperature. (author)

  18. Carbohydrate-rich high-molecular-mass antigens are strongly recognized during experimental Histoplasma capsulatum infection

    Directory of Open Access Journals (Sweden)

    Fabrine Sales Massafera Tristão

    2012-04-01

    Full Text Available INTRODUCTION: During histoplasmosis, Histoplasma capsulatum soluble antigens (CFAg can be naturally released by yeast cells. Because CFAg can be specifically targeted during infection, in the present study we investigated CFAg release in experimental murine histoplasmosis, and evaluated the host humoral immune response against high-molecular-mass antigens (hMMAg. >150 kDa, the more immunogenic CFAg fraction. METHODS: Mice were infected with 2.2x10(4 H. capsulatum IMT/HC128 yeast cells. The soluble CFAg, IgG anti-CFAg, IgG anti-hMMAg, and IgG-hMMAg circulating immune complexes (CIC levels were determined by enzymelinked immunosorbent assay, at days 0, 7, 14, and 28 post-infection. RESULTS: We observed a progressive increase in circulating levels of CFAg, IgG anti-CFAg, IgG anti-hMMAg, and IgG-hMMAg CIC after H. capsulatum infection. The hMMAg showed a high percentage of carbohydrates and at least two main immunogenic components. CONCLUSIONS: We verified for the first time that hMMAg from H. capsulatum IMT/HC128 strain induce humoral immune response and lead to CIC formation during experimental histoplasmosis.

  19. Phase I study utilizing a novel antigen-presenting cell-targeted vaccine with Toll-like receptor stimulation to induce immunity to self-antigens in cancer patients.

    Science.gov (United States)

    Morse, Michael A; Chapman, Robert; Powderly, John; Blackwell, Kimberly; Keler, Tibor; Green, Jennifer; Riggs, Renee; He, Li-Zhen; Ramakrishna, Venky; Vitale, Laura; Zhao, Biwei; Butler, Stephen A; Hobeika, Amy; Osada, Takuya; Davis, Thomas; Clay, Timothy; Lyerly, H Kim

    2011-07-15

    The use of tumor-derived proteins as cancer vaccines is complicated by tolerance to these self-antigens. Tolerance may be broken by immunization with activated, autologous, ex vivo generated and antigen-loaded, antigen-presenting cells (APC); however, targeting tumor antigen directly to APC in vivo would be a less complicated strategy. We wished to test whether targeted delivery of an otherwise poorly immunogenic, soluble antigen to APC through their mannose receptors (MR) would induce clinically relevant immunity. Two phase I studies were conducted with CDX-1307, a vaccine composed of human chorionic gonadotropin beta-chain (hCG-β) fused to an MR-specific monoclonal antibody, administered either locally (intradermally) or systemically (intravenously) in patients with advanced epithelial malignancies. An initial dose escalation of single-agent CDX-1307 was followed by additional cohorts of CDX-1307 combined with granulocyte-macrophage colony-stimulating factor (GM-CSF) and the Toll-like receptor (TLR) 3 agonist polyinosinic-polycytidylic acid (poly-ICLC) and TLR7/8 agonist resiquimod to activate the APC. CDX-1307 induced consistent humoral and T-cell responses to hCG-β when coadministered with TLR agonists. Greater immune responses and clinical benefit, including the longest duration of stable disease, were observed with immunization combined with local TLR agonists. Immune responses were induced equally efficiently in patients with elevated and nonelevated levels of serum hCG-β. Antibodies within the serum of vaccinated participants had tumor suppressive function in vitro. Toxicity consisted chiefly of mild injection site reactions. APC targeting and activation induce adaptive immunity against poorly immunogenic self-antigens which has implications for enhancing the efficacy of cancer immunotherapy.

  20. Targeted delivery of antigen to intestinal dendritic cells induces oral tolerance and prevents autoimmune diabetes in NOD mice.

    Science.gov (United States)

    Chen, Yulin; Wu, Jie; Wang, Jiajia; Zhang, Wenjing; Xu, Bohui; Xu, Xiaojun; Zong, Li

    2018-03-15

    The intestinal immune system is an ideal target to induce immune tolerance physiologically. However, the efficiency of oral protein antigen delivery is limited by degradation of the antigen in the gastrointestinal tract and poor uptake by antigen-presenting cells. Gut dendritic cells (DCs) are professional antigen-presenting cells that are prone to inducing antigen-specific immune tolerance. In this study, we delivered the antigen heat shock protein 65-6×P277 (H6P) directly to the gut DCs of NOD mice through oral vaccination with H6P-loaded targeting nanoparticles (NPs), and investigated the ability of this antigen to induce immune tolerance to prevent autoimmune diabetes in NOD mice. A targeting NP delivery system was developed to encapsulate H6P, and the ability of this system to protect and facilitate H6P delivery to gut DCs was assessed. NOD mice were immunised with H6P-loaded targeting NPs orally once a week for 7 weeks and the onset of diabetes was assessed by monitoring blood glucose levels. H6P-loaded targeting NPs protected the encapsulated H6P from degradation in the gastrointestinal tract environment and significantly increased the uptake of H6P by DCs in the gut Peyer's patches (4.1 times higher uptake compared with the control H6P solution group). Oral vaccination with H6P-loaded targeting NPs induced antigen-specific T cell tolerance and prevented diabetes in 100% of NOD mice. Immune deviation (T helper [Th]1 to Th2) and CD4 + CD25 + FOXP3 + regulatory T cells were found to participate in the induction of immune tolerance. In this study, we successfully induced antigen-specific T cell tolerance and prevented the onset of diabetes in NOD mice. To our knowledge, this is the first attempt at delivering antigen to gut DCs using targeting NPs to induce T cell tolerance.

  1. Lack of chemically induced mutation in repair-deficient mutants of yeast

    International Nuclear Information System (INIS)

    Prakash, L.

    1974-01-01

    Two genes, rad6 and rad9, that confer radiation sensitivity in the yeast Saccharomyces cerevisiae also greatly reduce the frequency of chemically-induced reversions of a tester mutant cyc1-131, which is a chain initiation mutant in the structural gene determining iso-1-cytochrome c. Mutations induced by ethyl methanesulfonate (EMS), diethyl sulfate (DES), methyl methanesulfonate (MMS), dimethyl sulfate (DMS), nitroquinoline oxide (NQO), nitrosoguanidine (NTG), nitrogen mustard (HN2), β-propiolactone, and tritiated uridine, as well as mutations induced by ultraviolet light (UV) and ionizing radiation were greatly diminished in strains homozygous for either the rad6 or rad9 gene. Nitrous acid and nitrosoimidazolidone (NIL), on the other hand, were highly mutagenic in these repair-deficient mutants, and at low doses, these mutagens acted with about the same efficiency as in the normal RAD strain. At high doses of either nitrous acid or NIL, however, reversion frequencies were significantly reduced in the two rad mutants compared to normal strains. Although both rad mutants are immutable to about the same extent, the rad9 strains tend to be less sensitive to the lethal effect of chemical mutagens than rad6 strains. It is concluded that yeast requires a functional repair system for mutation induction by chemical agents. (auth)

  2. Lack of chemically induced mutation in repair-deficient mutants of yeast.

    Science.gov (United States)

    Prakash, L

    1974-12-01

    Two genes, rad6 and rad9, that confer radiation sensitivity in the yeast Saccharomyces cerevisiae also greatly reduce the frequency of chemically-induced reversions of a tester mutant cyc1-131, which is a chain initiation mutant in the structural gene determining iso-1-cytochrome c. Mutations induced by ethyl methanesulfonate (EMS), diethyl sulfate (DES), methyl methanesulfonate (MMS), dimethyl sulfate (DMS), nitroquinoline oxide (NQO), nitrosoguanidine (NTG), nitrogen mustard (HN2), beta-propiolactone, and tritiated uridine, as well as mutations induced by ultraviolet light (UV) and ionizing radiation were greatly diminished in strains homozygous for either the rad6 or rad9 gene. Nitrous acid and nitrosoimidazolidone (NIL), on the other hand, were highly mutagenic in these repair-deficient mutants, and at low doses, these mutagens acted with about the same efficiency as in the normal RAD strain. At high doses of either nitrous acid or NIL, however, reversion frequencies were significantly reduced in the two rad mutants compared to normal strains. Although both rad mutants are immutable to about the same extent, the rad9 strains tend to be less sensitive to the lethal effect of chemical mutagens than rad6 strains. It is concluded that yeast requires a functional repair system for mutation induction by chemical agents.

  3. Conditionally controlling nuclear trafficking in yeast by chemical-induced protein dimerization.

    Science.gov (United States)

    Xu, Tao; Johnson, Cole A; Gestwicki, Jason E; Kumar, Anuj

    2010-11-01

    We present here a protocol to conditionally control the nuclear trafficking of target proteins in yeast. In this system, rapamycin is used to heterodimerize two chimeric proteins. One chimera consists of a FK506-binding protein (FKBP12) fused to a cellular 'address' (nuclear localization signal or nuclear export sequence). The second chimera consists of a target protein fused to a fluorescent protein and the FKBP12-rapamycin-binding (FRB) domain from FKBP-12-rapamycin associated protein 1 (FRAP1, also known as mTor). Rapamycin induces dimerization of the FKBP12- and FRB-containing chimeras; these interactions selectively place the target protein under control of the cell address, thereby directing the protein into or out of the nucleus. By chemical-induced dimerization, protein mislocalization is reversible and enables the identification of conditional loss-of-function and gain-of-function phenotypes, in contrast to other systems that require permanent modification of the targeted protein. Yeast strains for this analysis can be constructed in 1 week, and the technique allows protein mislocalization within 15 min after drug treatment.

  4. Hepatitis B surface antigen concentrations in patients with HIV/HBV co-infection.

    Directory of Open Access Journals (Sweden)

    Jerzy Jaroszewicz

    Full Text Available HBsAg clearance is associated with clinical cure of chronic hepatitis B virus (HBV infection. Quantification of HBsAg may help to predict HBsAg clearance during the natural course of HBV infection and during antiviral therapy. Most studies investigating quantitative HBsAg were performed in HBV mono-infected patients. However, the immune status is considered to be important for HBsAg decline and subsequent HBsAg loss. HIV co-infection unfavorably influences the course of chronic hepatitis B. In this cross-sectional study we investigated quantitative HBsAg in 173 HBV/HIV co-infected patients from 6 centers and evaluated the importance of immunodeficiency and antiretroviral therapy. We also compared 46 untreated HIV/HBV infected patients with 46 well-matched HBV mono-infected patients. HBsAg levels correlated with CD4 T-cell count and were higher in patients with more advanced HIV CDC stage. Patients on combination antiretroviral therapy (cART including nucleos(tide analogues active against HBV demonstrated significant lower HBsAg levels compared to untreated patients. Importantly, HBsAg levels were significantly lower in patients who had a stronger increase between nadir CD4 and current CD4 T-cell count during cART. Untreated HIV/HBV patients demonstrated higher HBsAg levels than HBV mono-infected patients despite similar HBV DNA levels. In conclusion, HBsAg decline is dependent on an effective immune status. Restoration of CD4 T-cells during treatment with cART including nucleos(tide analogues seems to be important for HBsAg decrease and subsequent HBsAg loss.

  5. 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

  6. Effect on HBs antigen clearance of addition of pegylated interferon alfa-2a to nucleos(t)ide analogue therapy versus nucleos(t)ide analogue therapy alone in patients with HBe antigen-negative chronic hepatitis B and sustained undetectable plasma hepatitis B virus DNA: a randomised, controlled, open-label trial.

    Science.gov (United States)

    Bourlière, Marc; Rabiega, Pascaline; Ganne-Carrie, Nathalie; Serfaty, Lawrence; Marcellin, Patrick; Barthe, Yoann; Thabut, Dominique; Guyader, Dominique; Hezode, Christophe; Picon, Magali; Causse, Xavier; Leroy, Vincent; Bronowicki, Jean Pierre; Carrieri, Patrizia; Riachi, Ghassan; Rosa, Isabelle; Attali, Pierre; Molina, Jean Michel; Bacq, Yannick; Tran, Albert; Grangé, Jean Didier; Zoulim, Fabien; Fontaine, Hélène; Alric, Laurent; Bertucci, Inga; Bouvier-Alias, Magali; Carrat, Fabrice

    2017-03-01

    Findings from uncontrolled studies suggest that addition of pegylated interferon in patients with HBe antigen (HBeAg)-negative chronic hepatitis B receiving nucleos(t)ide analogues with undetectable plasma hepatitis B virus (HBV) DNA might increase HBs antigen (HBsAg) clearance. We aimed to assess this strategy. In this randomised, controlled, open-label trial, we enrolled patients aged 18-75 years with HBeAg-negative chronic hepatitis B and documented negative HBV DNA while on stable nucleos(t)ide analogue regimens for at least 1 year from 30 hepatology tertiary care wards in France. Patients had to have an alanine aminotransferase concentration of less than or equal to five times the upper normal range, no hepatocellular carcinoma, and a serum α fetoprotein concentration of less than 50 ng/mL, normal dilated fundus oculi examination, and a negative pregnancy test in women. Patients with contraindications to pegylated interferon were not eligible. A centralised randomisation used computer-generated lists of random permuted blocks of four with stratification by HBsAg titres (sida et les hépatites virales (France Recherche Nord&sud Sida-vih Hepatites). Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium

    DEFF Research Database (Denmark)

    Smith, Ida Mosbech; Baker, A; Arneborg, Nils

    2015-01-01

    distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase....... In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability......). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. SIGNIFICANCE AND IMPACT...

  8. Immunogenicity is unrelated to protective immunity when induced by soluble and particulate antigens from Nocardia brasiliensis in BALB/c mice.

    Science.gov (United States)

    Salinas-Carmona, Mario C; Ramos, Alma I; Pérez-Rivera, Isabel

    2006-08-01

    Cell-mediated immunity plays a major role in protection against intracellular microbes. Nocardia brasiliensis is a facultative intracellular pathogen that causes chronic actinomycetoma. In this work, we injected BALB/c mice with soluble P24 and particulate antigens from N. brasiliensis. A higher antibody titer and lymphocyte proliferation was induced by the particulate antigen than by the soluble antigen. However, five months after antigen injection, antibody concentration and lymphocyte proliferation were similar. An increase in CD45R and CD4 T cells was unrelated to protective immunity. Active immunization with soluble or particulate antigens induced complete protection during the primary immune response. This protective response was IgM mediated. The higher immunogenicity was not related to protective immunity since the particulate antigen induced protection similar to the soluble antigen. Using particulate antigens for vaccination guarantees a stronger immune response, local and systemic side effects, but not necessarily protection.

  9. Perillyl alcohol suppresses antigen-induced immune responses in the lung

    International Nuclear Information System (INIS)

    Imamura, Mitsuru; Sasaki, Oh; Okunishi, Katsuhide; Nakagome, Kazuyuki; Harada, Hiroaki; Kawahata, Kimito; Tanaka, Ryoichi; Yamamoto, Kazuhiko; Dohi, Makoto

    2014-01-01

    Highlights: •Perillyl alcohol (POH) is an isoprenoid which inhibits the mevalonate pathway. •We examined whether POH suppresses immune responses with a mouse model of asthma. •POH treatment during sensitization suppressed Ag-induced priming of CD4 + T cells. •POH suppressed airway eosinophila and cytokine production in thoracic lymph nodes. -- Abstract: Perillyl alcohol (POH) is an isoprenoid which inhibits farnesyl transferase and geranylgeranyl transferase, key enzymes that induce conformational and functional changes in small G proteins to conduct signal production for cell proliferation. Thus, it has been tried for the treatment of cancers. However, although it affects the proliferation of immunocytes, its influence on immune responses has been examined in only a few studies. Notably, its effect on antigen-induced immune responses has not been studied. In this study, we examined whether POH suppresses Ag-induced immune responses with a mouse model of allergic airway inflammation. POH treatment of sensitized mice suppressed proliferation and cytokine production in Ag-stimulated spleen cells or CD4 + T cells. Further, sensitized mice received aerosolized OVA to induce allergic airway inflammation, and some mice received POH treatment. POH significantly suppressed indicators of allergic airway inflammation such as airway eosinophilia. Cytokine production in thoracic lymph nodes was also significantly suppressed. These results demonstrate that POH suppresses antigen-induced immune responses in the lung. Considering that it exists naturally, POH could be a novel preventive or therapeutic option for immunologic lung disorders such as asthma with minimal side effects

  10. Mitotic recombination induced by chemical and physical agents in the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Davies, P.J.; Evans, W.E.; Parry, J.M.

    1975-01-01

    The treatment of diploid cultures of yeast with ultraviolet light (uv), γ-rays, nitrous acid (na) and ethyl methane sulphonate (ems) results in increases in cell death, mitotic gene conversion and crossing-over. Acridine orange (ao) treatment, in contrast, was effective only in increasing the frequency of gene conversion. The individual mutagens were effective in the order uv>na>γ-rays>ao>ems. Prior treatment of yeast cultures in starvation medium produced a significant reduction in the yield of induced gene conversion. The results have been interpreted on the basis of a general model of mitotic gene conversion which involves the post-replication repair of induced lesions involving de novo DNA synthesis without genetic exchange. In contrast mitotic crossing-over appears to involve the action of a repair system independent from excision or post-replication repair which involves genetic exchange between homologous chromosomes

  11. Animal vaccines based on orally presented yeast recombinants.

    Science.gov (United States)

    Shin, Min-Kyoung; Yoo, Han Sang

    2013-09-13

    In veterinary vaccinology, the oral route of administration is an attractive alternative compared to the commonly used parenteral route. Yeasts have a number of properties that make them potential live delivery systems for oral vaccination purposes such as their high expression levels, their GRAS status, adjuvant properties, and post-translational modification possibilities. Consequently, yeasts have been employed for the expression of heterologous genes and for the production of therapeutic proteins. Yeast-based vaccines are reviewed with regard to their ability to express and produce antigens from pathogens for veterinary use. Many of these vaccines have been shown to elicit protective immune responses following oral immunization in animals. Ultimately, yeast-based oral vaccines may offer a potential opportunity for the development of novel ideal vaccines in veterinary medicine. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. [Intragenic mitotic recombination induced by ultraviolet and gamma rays in radiosensitive mutants of Saccharomyces cerevisiae yeasts].

    Science.gov (United States)

    Zakharov, I A; Kasinova, G V; Koval'tsova, S V

    1983-01-01

    The effect of UV- and gamma-irradiation on the survival and intragenic mitotic recombination (gene conversion) of 5 radiosensitive mutants was studied in comparison with the wild type. The level of spontaneous conversion was similar for RAD, rad2 and rad15, mutations xrs2 and xrs4 increasing and rad54 significantly decreasing it. The frequency of conversion induced by UV-light was greater in rad2, rad15 and xrs2 mutants and lower in xrs4, as compared to RAD. Gamma-irradiation caused induction of gene conversion with an equal frequency in RAD, rad2, rad15. Xrs2 and xrs4 mutations slightly decreased gamma-induced conversion. In rad54 mutant, UV-and gamma-induced conversion was practically absent. In the wild type yeast, a diploid strain is more resistant than a haploid, whereas in rad54 a diploid strain has the same or an increased sensitivity, as compared to a haploid strain (the "inverse ploidy effect"). This effect and also the block of induced mitotic recombination caused by rad54 indicate the presence in the yeast Saccharomyces cerevisiae of repair pathways of UV- and gamma-induced damages acting in diploid cells and realised by recombination. The data obtained as a result of many years' investigation of genetic effects in radiosensitive mutants of yeast are summarised and considered.

  13. The phytopathogenic virulent effector protein RipI induces apoptosis in budding yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Deng, Meng-Ying; Sun, Yun-Hao; Li, Pai; Fu, Bei; Shen, Dong; Lu, Yong-Jun

    2016-10-01

    Virulent protein toxins secreted by the bacterial pathogens can cause cytotoxicity by various molecular mechanisms to combat host cell defense. On the other hand, these proteins can also be used as probes to investigate the defense pathway of host innate immunity. Ralstonia solanacearum, one of the most virulent bacterial phytopathogens, translocates more than 70 effector proteins via type III secretion system during infection. Here, we characterized the cytotoxicity of effector RipI in budding yeast Saccharomyce scerevisiae, an alternative host model. We found that over-expression of RipI resulted in severe growth defect and arginine (R) 117 within the predicted integrase motif was required for inhibition of yeast growth. The phenotype of death manifested the hallmarks of apoptosis. Our data also revealed that RipI-induced apoptosis was independent of Yca1 and mitochondria-mediated apoptotic pathways because Δyca1 and Δaif1 were both sensitive to RipI as compared with the wild type. We further demonstrated that RipI was localized in the yeast nucleus and the N-terminal 1-174aa was required for the localization. High-throughput RNA sequencing analysis showed that upon RipI over-expression, 101 unigenes of yeast ribosome presented lower expression level, and 42 GO classes related to the nucleus or recombination were enriched with differential expression levels. Taken together, our data showed that a nuclear-targeting effector RipI triggers yeast apoptosis, potentially dependent on its integrase function. Our results also provided an alternative strategy to dissect the signaling pathway of cytotoxicity induced by the protein toxins. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Characterisation of antibody responses in pigs induced by recombinant oncosphere antigens from Taenia solium.

    Science.gov (United States)

    Jayashi, César M; Gonzalez, Armando E; Castillo Neyra, Ricardo; Kyngdon, Craig T; Gauci, Charles G; Lightowlers, Marshall W

    2012-12-14

    Recombinant antigens cloned from the oncosphere life cycle stage of the cestode parasite Taenia solium (T. solium) have been proven to be effective as vaccines for protecting pigs against infections with T. solium. Previous studies have defined three different host protective oncosphere antigens, TSOL18, TSOL16 and TSOL45. In this study, we evaluated the potential for combining the antigens TSOL16 and TSOL18 as a practical vaccine. Firstly, in a laboratory trial, we compared the immunogenicity of the combined antigens (TSOL16/18) versus the immunogenicity of the antigens separately. Secondly, in a field trial, we tested the ability of the TSOL16/18 vaccine to induce detectable antibody responses in animals living under environmental stress and traditionally reared in areas where T. solium cysticercosis is endemic; and finally, we characterised the immune response of the study population. Pigs of 8-16 weeks of age were vaccinated with 200 μg each of TSOL16 and TSOL18, plus 5mg of Quil-A. Specific total IgG, IgG(1) and IgG(2) antibody responses induced by TSOL16 and TSOL18 were determined with ELISA. The immunogenicity of both antigens was retained in the combined TSOL16/18 vaccine. The combined vaccine TSOL16/18 induced detectable specific anti-TSOL18 antibody responses in 100% (113/113) and specific anti-TSOL16 in 99% (112/113) of the vaccinated animals measured at 2 weeks following the booster vaccination. From the two IgG antibody subtypes analysed we found there was stronger response to IgG(2). Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Four inducible promoters for controlled gene expression in the oleaginous yeast Rhodotorula toruloides

    Directory of Open Access Journals (Sweden)

    Alexander Michael Bedford Johns

    2016-10-01

    Full Text Available Rhodotorula (Rhodosporidium toruloides is an oleaginous yeast with great biotechnological potential, capable of accumulating lipid up to 70 % of its dry biomass, and of carotenoid biosynthesis. However, few molecular genetic tools are available for manipulation of this basidiomycete yeast and its high genomic GC content can make routine cloning difficult. We have developed plasmid vectors for transformation of R. toruloides which include elements for Saccharomyces cerevisiae in-yeast assembly; this method is robust to the assembly of GC-rich DNA and of large plasmids. Using such vectors we screened for controllable promoters, and identified inducible promoters from the genes NAR1, ICL1, CTR3 and MET16. These four promoters have independent induction/repression conditions and exhibit different levels and rates of induction in R. toruloides, making them appropriate for controllable transgene expression in different experimental situations. Nested deletions were used to identify regulatory regions in the four promoters, and to delimit the minimal inducible promoters, which are as small as 200 bp for the NAR1 promoter. The NAR1 promoter shows very tight regulation under repressed conditions as determined both by an EGFP reporter gene and by conditional rescue of a leu2 mutant. These new tools facilitate molecular genetic manipulation and controllable gene expression in R. toruloides.

  16. Hyperthermia-induced alteration of yeast susceptibility to mutation

    International Nuclear Information System (INIS)

    Mitchel, R.E.J.; Morrison, D.P.

    1985-01-01

    Diploid yeast (s. cerevisiae) were examined for alterations in susceptibility to induced mutation following hyperthermia treatment. In cells grown at 23 0 C, a non-lethal heat exposure (38 0 C, 30 min) markedly suppressed mutation induced by a subsequent non-killing dose of MNNG of MNU. Mutation by ENU, 8-MOP + UVA, or γ-rays was not affected. An intermediate level of mutation suppression was observed for mutation by 254nm UV or MMS. Mutation by MNNG was not suppressed by the same heat treatment delivered after the mutagen exposure. In a split dose experiment (two MNNG treatments separated by a heat exposure) no suppression of mutation was observed. Treatment with cycloheximide mimicked the effect of heat treatment. These data suggest that mutation induction by MNNG or MNU is protein synthesis dependent, i.e. an error-prone repair system is induced by exposure to MNNG or MNU but not by ENU, 8-MOP+UVA or γ-irradiation. We propose that hyperthermia treatment, by inducing stress protein synthesis at the expense of normal protein synthesis, precludes induction of this error-prone system. Therefore, in heat treated cells, DNA lesions produced by MNNG or MNU exposure must be resolved by an essentially constitutive system which is less error-prone than the inducible one

  17. Axotomy induces MHC class I antigen expression on rat nerve cells

    DEFF Research Database (Denmark)

    Maehlen, J; Schröder, H D; Klareskog, L

    1988-01-01

    Immunomorphological staining demonstrates that class I major histocompatibility complex (MHC)-coded antigen expression can be selectively induced on otherwise class I-negative rat nerve cells by peripheral axotomy. Induction of class I as well as class II antigen expression was simultaneously seen...... on non-neural cells in the immediate vicinity of the injured nerve cells. As nerve regeneration after axotomy includes growth of new nerve cell processes and formation of new nerve cell contacts, the present findings raise the question of a role for MHC-coded molecules in cell-cell interactions during...... nerve cell growth....

  18. Antibody-mediated immunotherapy against chronic hepatitis B virus infection.

    Science.gov (United States)

    Gao, Ying; Zhang, Tian-Ying; Yuan, Quan; Xia, Ning-Shao

    2017-08-03

    The currently available drugs to treat hepatitis B virus (HBV) infection include interferons and nucleos(t)ide analogs, which can only induce disease remission and are inefficient for the functional cure of patients with chronic HBV infection (CHB). Since high titers of circulating hepatitis B surface antigen (HBsAg) may be essential to exhaust the host anti-HBV immune response and they cannot be significantly reduced by current drugs, new antiviral strategies aiming to suppress serum hepatitis B surface antigen (HBsAg) could help restore virus-specific immune responses and promote the eradication of the virus. As an alternative strategy, immunotherapy with HBsAg-specific antibodies has shown some direct HBsAg suppression effects in several preclinical and clinical trial studies. However, most described previously HBsAg-specific antibodies only had very short-term HBsAg suppression effects in CHB patients and animal models mimicking persistent HBV infection. More-potent antibodies with long-lasting HBsAg clearance effects are required for the development of the clinical application of antibody-mediated immunotherapy for CHB treatment. Our recent study described a novel mAb E6F6 that targets a unique epitope on HBsAg. It could durably suppress the levels of HBsAg and HBV DNA via Fcγ receptor-dependent phagocytosis in vivo. In this commentary, we summarize the current research progress, including the therapeutic roles and mechanisms of antibody-mediated HBV clearance as well as the epitope-determined therapeutic potency of the antibody. These insights may provide some clues and guidance to facilitate the development of therapeutic antibodies against persistent viral infection.

  19. Perillyl alcohol suppresses antigen-induced immune responses in the lung

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, Mitsuru; Sasaki, Oh; Okunishi, Katsuhide; Nakagome, Kazuyuki; Harada, Hiroaki; Kawahata, Kimito; Tanaka, Ryoichi; Yamamoto, Kazuhiko [Department of Allergy and Rheumatology, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan); Dohi, Makoto, E-mail: mdohi-tky@umin.ac.jp [Department of Allergy and Rheumatology, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan); Institute of Respiratory Immunology, Shibuya Clinic for Respiratory Diseases and Allergology, Tokyo (Japan)

    2014-01-03

    Highlights: •Perillyl alcohol (POH) is an isoprenoid which inhibits the mevalonate pathway. •We examined whether POH suppresses immune responses with a mouse model of asthma. •POH treatment during sensitization suppressed Ag-induced priming of CD4{sup +} T cells. •POH suppressed airway eosinophila and cytokine production in thoracic lymph nodes. -- Abstract: Perillyl alcohol (POH) is an isoprenoid which inhibits farnesyl transferase and geranylgeranyl transferase, key enzymes that induce conformational and functional changes in small G proteins to conduct signal production for cell proliferation. Thus, it has been tried for the treatment of cancers. However, although it affects the proliferation of immunocytes, its influence on immune responses has been examined in only a few studies. Notably, its effect on antigen-induced immune responses has not been studied. In this study, we examined whether POH suppresses Ag-induced immune responses with a mouse model of allergic airway inflammation. POH treatment of sensitized mice suppressed proliferation and cytokine production in Ag-stimulated spleen cells or CD4{sup +} T cells. Further, sensitized mice received aerosolized OVA to induce allergic airway inflammation, and some mice received POH treatment. POH significantly suppressed indicators of allergic airway inflammation such as airway eosinophilia. Cytokine production in thoracic lymph nodes was also significantly suppressed. These results demonstrate that POH suppresses antigen-induced immune responses in the lung. Considering that it exists naturally, POH could be a novel preventive or therapeutic option for immunologic lung disorders such as asthma with minimal side effects.

  20. 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)

  1. Human Parvovirus B19 Induced Apoptotic Bodies Contain Altered Self-Antigens that are Phagocytosed by Antigen Presenting Cells

    Science.gov (United States)

    Thammasri, Kanoktip; Rauhamäki, Sanna; Wang, Liping; Filippou, Artemis; Kivovich, Violetta; Marjomäki, Varpu; Naides, Stanley J.; Gilbert, Leona

    2013-01-01

    Human parvovirus B19 (B19V) from the erythrovirus genus is known to be a pathogenic virus in humans. Prevalence of B19V infection has been reported worldwide in all seasons, with a high incidence in the spring. B19V is responsible for erythema infectiosum (fifth disease) commonly seen in children. Its other clinical presentations include arthralgia, arthritis, transient aplastic crisis, chronic anemia, congenital anemia, and hydrops fetalis. In addition, B19V infection has been reported to trigger autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. However, the mechanisms of B19V participation in autoimmunity are not fully understood. B19V induced chronic disease and persistent infection suggests B19V can serve as a model for viral host interactions and the role of viruses in the pathogenesis of autoimmune diseases. Here we investigate the involvement of B19V in the breakdown of immune tolerance. Previously, we demonstrated that the non-structural protein 1 (NS 1) of B19V induces apoptosis in non-permissive cells lines and that this protein can cleave host DNA as well as form NS1-DNA adducts. Here we provide evidence that through programmed cell death, apoptotic bodies (ApoBods) are generated by B19V NS1 expression in a non-permissive cell line. Characterization of purified ApoBods identified potential self-antigens within them. In particular, signature self-antigens such as Smith, ApoH, DNA, histone H4 and phosphatidylserine associated with autoimmunity were present in these ApoBods. In addition, when purified ApoBods were introduced to differentiated macrophages, recognition, engulfment and uptake occurred. This suggests that B19V can produce a source of self-antigens for immune cell processing. The results support our hypothesis that B19V NS1-DNA adducts, and nucleosomal and lysosomal antigens present in ApoBods created in non-permissive cell lines, are a source of self-antigens. PMID:23776709

  2. New mutations affecting induced mutagenesis in yeast.

    Science.gov (United States)

    Lawrence, C W; Krauss, B R; Christensen, R B

    1985-01-01

    Previously isolated mutations in baker's yeast, Saccharomyces cerevisiae, that impair induced mutagenesis were all identified with the aid of tests that either exclusively or predominantly detect base-pair substitutions. To avoid this bias, we have screened 11 366 potentially mutant clones for UV-induced reversion of the frameshift allele, his4-38, and have identified 10 mutants that give much reduced yields of revertants. Complementation and recombination tests show that 6 of these carry mutations at the previously known REV1, REV1 and REV3 loci, while the remaining 4 define 3 new genes, REV4 (2 mutations), REV5 and REV6. The rev4 mutations are readily suppressed in many genetic backgrounds and, like the rev5 mutation, impart only a limited deficiency for induced mutagenesis: it is likely, therefore that the REV4+ and REV5+ gene functions are only remotely concerned with this process. The rev6 mutants have a more general deficiency, however, as well as marked sensitivity to UV and an increased spontaneous mutation rate, properties that suggest the REV6 gene is directly involved in mutation induction. The REV5 gene is located about 1 cM proximal to CYC1 on chromosome X.

  3. Detection of HBsAg and Anti HBc on donors of a blood bank by IRMA and ELISA methods

    International Nuclear Information System (INIS)

    Freire Martinez, D.Y.

    1985-10-01

    Comparative evaluation of two methods, Immunoradiometric Assay (IRMA) and Enzyme Immunoassay (ELISA), for detecting HBsAg and Anti HBc was made for determining which is the most advantageous and reliable. The study was made on 300 donors of the Hospital San Juan de Dios Blood Bank. In comparison with the reference method (IRMA), ELISA shows 91.67% of sensitivity. The Anti HBc detection by IRMA is more reliable than the HBsAg detection by IRMA and ELISA for determining the carrier state

  4. The involvement of topoisomerases and DNA polymerase I in the mechanism of induced thermal and radiation resistance in yeast

    International Nuclear Information System (INIS)

    Boreham, D.R.; Trivedi, A.; Weinberger, P.; Mitchel, R.E.

    1990-01-01

    Either an ionizing radiation exposure or a heat shock is capable of inducing both thermal tolerance and radiation resistance in yeast. Yeast mutants, deficient in topoisomerase I, in topoisomerase II, or in DNA polymerase I, were used to investigate the mechanism of these inducible resistances. The absence of either or both topoisomerase activities did not prevent induction of either heat or radiation resistance. However, if both topoisomerase I and II activities were absent, the sensitivity of yeast to become thermally tolerant (in response to a heat stress) was markedly increased. The absence of only topoisomerase I activity (top1) resulted in the constitutive expression of increased radiation resistance equivalent to that induced by a heat shock in wild-type cells, and the topoisomerase I-deficient cells were not further inducible by heat. This heat-inducible component of radiation resistance (or its equivalent constitutive expression in top1 cells) was, in turn, only a portion of the full response inducible by radiation. The absence of polymerase I activity had no detectable effect on either response. Our results indicate that the actual systems that confer resistance to heat or radiation are independent of either topoisomerase activity or DNA polymerase function, but suggest that topoisomerases may have a regulatory role during the signaling of these mechanisms. The results of our experiments imply that maintenance of correct DNA topology prevents induction of the heat-shock response, and that heat-shock induction of a component of the full radiation resistance in yeast may be the consequence of topoisomerase I inactivation

  5. Expression of death receptor 4 induces caspase-independent cell death in MMS-treated yeast.

    Science.gov (United States)

    Kang, Mi-Sun; Lee, Sung-Keun; Park, Chang-Shin; Kang, Ju-Hee; Bae, Sung-Ho; Yu, Sung-Lim

    2008-11-14

    DR4, a tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, is a key element in the extrinsic pathway of TRAIL/TRAIL receptor-related apoptosis that exerts a preferential toxic effect against tumor cells. However, TRAIL and DR4 are expressed in various normal cells, and recent studies indicate that DR4 has a number of non-apoptotic functions. In this study, we evaluated the effects of human DR4 expression in yeast to determine the function of DR4 in normal cells. The expression of DR4 in yeast caused G1 arrest, which resulted in transient growth inhibition. Moreover, treatment of DR4-expressing yeast with a DNA damaging agent, MMS, elicited drastic, and sustained cell growth inhibition accompanied with massive apoptotic cell death. Further analysis revealed that cell death in the presence of DNA damage and DR4 expression was not dependent on the yeast caspase, YCA1. Taken together, these results indicate that DR4 triggers caspase-independent programmed cell death during the response of normal cells to DNA damage.

  6. 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

  7. Kinetics of gene and chromosome mutations induced by UV-C in yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Koltovaya, N.; Kokoreva, A.; Senchenko, D.; Shvaneva, N.; Zhuchkina, N.

    2017-01-01

    The systematic study of the kinetics of UV-induced gene and structural mutations in eukaryotic cells was carried out on the basis of model yeast S. cerevisiae. A variety of genetic assays (all types of base pair substitutions, frameshifts, forward mutations canl, chromosomal and plasmid rearrangements) in haploid strains were used. Yeast cells were treated by UV-C light of fluence of energy up to 200 J/m"2. The kinetics of the induced gene and structural mutations is represented by a linear-quadratic and exponential functions. The slope of curves in log-log plots was not constant, had the value 2-4 and depended on the interval of doses. It was suggested that it is the superposition and dynamics of different pathways form the mutagenic responses of eukaryotic cells to UV-C light that cause the high-order curves. [ru

  8. Yeast-recombinant hepatitis B vaccine: efficacy with hepatitis B immune globulin in prevention of perinatal hepatitis B virus transmission

    International Nuclear Information System (INIS)

    Stevens, C.E.; Taylor, P.E.; Tong, M.J.; Toy, P.T.; Vyas, G.N.; Nair, P.V.; Weissman, J.Y.; Krugman, S.

    1987-01-01

    A yeast-recombinant hepatitis B vaccine was licensed recently by the Food and Drug administration and is now available. To assess the efficacy of the yeast-recombinant vaccine, the authors administered the vaccine in combination with hepatitis B immune globulin to high-risk newborns. If infants whose mothers were positive for both hepatitis B surface antigen and the e antigen receive no immunoprophylaxis, 70% to 90% become infected with the virus, and almost all become chronic carriers. Among infants in this study who received hepatitis B immune globulin at birth and three 5- + g doses of yeast-recombinant hepatitis B vaccine, only 4.8% became chronic carriers, a better than 90% level of protection and a rate that is comparable with that seen with immune globulin and plasma-derived hepatitis B vaccine. Hepatitis surface antigen and antibodies were detected by radioimmunoassay. These data suggest that, in this high-risk setting, the yeast-recombinant vaccine is as effective as the plasma-derived vaccine in preventing hepatitis B virus infection and the chronic carrier state

  9. Targeting tumor antigens to secreted membrane vesicles in vivo induces efficient antitumor immune responses.

    Science.gov (United States)

    Zeelenberg, Ingrid S; Ostrowski, Matias; Krumeich, Sophie; Bobrie, Angélique; Jancic, Carolina; Boissonnas, Alexandre; Delcayre, Alain; Le Pecq, Jean-Bernard; Combadière, Béhazine; Amigorena, Sebastian; Théry, Clotilde

    2008-02-15

    Expression of non-self antigens by tumors can induce activation of T cells in vivo, although this activation can lead to either immunity or tolerance. CD8+ T-cell activation can be direct (if the tumor expresses MHC class I molecules) or indirect (after the capture and cross-presentation of tumor antigens by dendritic cells). The modes of tumor antigen capture by dendritic cells in vivo remain unclear. Here we examine the immunogenicity of the same model antigen secreted by live tumors either in association with membrane vesicles (exosomes) or as a soluble protein. We have artificially addressed the antigen to secreted vesicles by coupling it to the factor VIII-like C1C2 domain of milk fat globule epidermal growth factor-factor VIII (MFG-E8)/lactadherin. We show that murine fibrosarcoma tumor cells that secrete vesicle-bound antigen grow slower than tumors that secrete soluble antigen in immunocompetent, but not in immunodeficient, host mice. This growth difference is due to the induction of a more potent antigen-specific antitumor immune response in vivo by the vesicle-bound than by the soluble antigen. Finally, in vivo secretion of the vesicle-bound antigen either by tumors or by vaccination with naked DNA protects against soluble antigen-secreting tumors. We conclude that the mode of secretion can determine the immunogenicity of tumor antigens and that manipulation of the mode of antigen secretion may be used to optimize antitumor vaccination protocols.

  10. A Mitochondria-Dependent Pathway Mediates the Apoptosis of GSE-Induced Yeast

    OpenAIRE

    Cao, Sishuo; Xu, Wentao; Zhang, Nan; Wang, Yan; Luo, YunBo; He, Xiaoyun; Huang, Kunlun

    2012-01-01

    Grapefruit seed extract (GSE), which has powerful anti-fungal activity, can induce apoptosis in S. cerevisiae. The yeast cells underwent apoptosis as determined by testing for apoptotic markers of DNA cleavage and typical chromatin condensation by Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick End Labeling (TUNEL) and 4,6'-diaminidino-2-phenylindole (DAPI) staining and electron microscopy. The changes of ΔΨmt (mitochondrial transmembrane potential) and ROS (reactive oxygen species) ...

  11. 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

  12. Attenuation of yeast form of Paracoccidioides Brasiliensis by gamma irradiation

    International Nuclear Information System (INIS)

    Demicheli, Marina Cortez

    2006-01-01

    Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent mycosis in Latin America, and currently there is no effective vaccine. The aim of this work was to attenuate the yeast form of P. brasiliensis by gamma irradiation for further studies on vaccine research. P. brasiliensis (strain Pb-18) cultures were irradiated at doses between 0.5 and 8.0 kGy. After each dose the fungal cells were plated and after 10 days the colony forming units (CFU) counted. The viability of the irradiated cells was measured using the dyes Janus green and methylene blue, and protein synthesis by incorporation of L 35 S methionine. The comparison between the antigenic profile of irradiated and control yeast was made by Western blot and the virulence evaluated by the inoculation in C 57 Bl/J6 and Balb/c mice. Morphological changes in irradiated yeast were evaluated by electronic microscopy and DNA integrity by electrophoresis in agarose gel. At 6.5 kGy the yeast lost the reproductive capacity. The viability and the incorporation of L- 35 S methionine were the same in control and up to 6.5 kGy irradiated cells, but 6.5 kGy irradiated yeast secreted 40% less proteins. The Western blot profile was clearly similar in control and 6.5 kGy irradiated yeast. No CFU could be recovered from the tissues of the mice infected with the radio attenuated yeast. At the dose of 6.5 kGy the DNA was degraded and this damage was not repaired. The transmission electronic microscopy showed significant alterations in the nucleus of the irradiated cells. The scanning electronic microscopy showed that two hours after the irradiation the cells were collapsed or presented deep folds in the surface, however these injury were reversible. We concluded that for P. brasiliensis yeast cells it was possible to find a dose in which the pathogen loses its reproductive ability and virulence, while retaining its viability, metabolic activity and the antigenic profile. (author)

  13. Alpha-ketoglutarate enhances freeze-thaw tolerance and prevents carbohydrate-induced cell death of the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Bayliak, Maria M; Hrynkiv, Olha V; Knyhynytska, Roksolana V; Lushchak, Volodymyr I

    2018-01-01

    Stress resistance and fermentative capability are important quality characteristics of baker's yeast. In the present study, we examined protective effects of exogenous alpha-ketoglutarate (AKG), an intermediate of the tricarboxylic acid cycle and amino acid metabolism, against freeze-thaw and carbohydrate-induced stresses in the yeast Saccharomyces cerevisiae. Growth on AKG-supplemented medium prevented a loss of viability and improved fermentative capacity of yeast cells after freeze-thaw treatment. The cells grown in the presence of AKG had higher levels of amino acids (e.g., proline), higher metabolic activity and total antioxidant capacity, and higher activities of catalase, NADP-dependent glutamate dehydrogenase and glutamine synthase compared to control ones. Both synthesis of amino acids and enhancement of antioxidant system capacity could be involved in AKG-improved freeze-thaw tolerance in S. cerevisiae. Cell viability dramatically decreased under incubation of stationary-phase yeast cells in 2% glucose or fructose solutions (in the absence of the other nutrients) as compared with incubation in distilled water or in 10 mM AKG solution. The decrease in cell viability was accompanied by acidification of the medium, and decrease in cellular respiration, aconitase activity, and levels of total protein and free amino acids. The supplementation with 10 mM AKG effectively prevented carbohydrate-induced yeast death. Protective mechanisms of AKG could be associated with the intensification of respiration and prevention of decreasing protein level as well as with direct antioxidant AKG action.

  14. 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.

  15. Safety and immunogenicity of a combined hepatitis B virus-Haemophilus influenzae type B vaccine comprising a synthetic antigen in healthy adults.

    Science.gov (United States)

    Aguilar-Betancourt, Arístides; González-Delgado, Carlos Alberto; Cinza-Estévez, Z; Martínez-Cabrera, Jesus; Véliz-Ríos, Gloria; Alemán-Zaldívar, Regis; Alonso-Martínez, M I; Lago-Baños, M; Puble-Alvarez, N; Delahanty-Fernandez, A; Juvier-Madrazo, A I; Ortega-León, D; Olivera-Ruano, L; Correa-Fernández, A; Abreu-Reyes, D; Soto-Mestre, E; Pérez-Pérez, M V; Figueroa-Baile, N; Pérez, L Hernandez; Rodríguez-Silva, A; Martínez-Díaz, E; Guillén-Nieto, G E; Muzio-González, Verena L

    2008-01-01

    The combined HB-Hib vaccine candidate Hebervac HB-Hib (CIGB, La Habana), comprising recombinant HBsAg and tetanus toxoid conjugate synthetic PRP antigens has shown to be highly immunogenic in animal models. A phase I open, controlled, randomized clinical trial was carried out to assess the safety and immunogenicity profile of this bivalent vaccine in 25 healthy adults who were positive for antibody to HBsAg (anti-HBs). The trial was performed according to Good Clinical Practices and Guidelines. Volunteers were randomly allocated to receive the combined vaccine or simultaneous administration of HB vaccine Heberbiovac-HB and Hib vaccine QuimiHib (CIGB, La Habana). All individuals were intramuscularly immunized with a unique dose of 10 microg HBsAg plus 10 microg conjugated synthetic PRP. Adverse events were actively recorded after vaccine administration. Total anti-HBs and IgG anti-PRP antibody titers were evaluated using commercial ELISA kits at baseline and 30 days post-vaccination. The combined vaccine candidate was safe and well tolerated. The most common adverse reactions were local pain, febricula, fever and local erythema. These reactions were all mild in intensity and resolved without medical treatment. Adverse events were mostly reported during the first 6-72 hours post-vaccination. There were no serious adverse events during the study. No severe or unexpected events were either recorded during the trial. The combined vaccine elicited an anti-HBs and anti-PRP booster response in 100% of subjects at day 30 of the immunization schedule. Anti-HBs and anti-PRP antibody levels had at least a two-fold increase compared to baseline sera. Even more, anti-HBs antibody titer showed a four-fold increase in 100% of volunteers in the study group. The results indicate that the combined HB-Hib vaccine produces increased antibody levels in healthy adults who have previously been exposed to these two antigens. To our knowledge, this is the first demonstration of safety and

  16. Limited transplantation of antigen-expressing hematopoietic stem cells induces long-lasting cytotoxic T cell responses.

    Directory of Open Access Journals (Sweden)

    Warren L Denning

    2011-02-01

    Full Text Available Harnessing the ability of cytotoxic T lymphocytes (CTLs to recognize and eradicate tumor or pathogen-infected cells is a critical goal of modern immune-based therapies. Although multiple immunization strategies efficiently induce high levels of antigen-specific CTLs, the initial increase is typically followed by a rapid contraction phase resulting in a sharp decline in the frequency of functional CTLs. We describe a novel approach to immunotherapy based on a transplantation of low numbers of antigen-expressing hematopoietic stem cells (HSCs following nonmyeloablative or partially myeloablative conditioning. Continuous antigen presentation by a limited number of differentiated transgenic hematopoietic cells results in an induction and prolonged maintenance of fully functional effector T cell responses in a mouse model. Recipient animals display high levels of antigen-specific CTLs four months following transplantation in contrast to dendritic cell-immunized animals in which the response typically declines at 4-6 weeks post-immunization. Majority of HSC-induced antigen-specific CD8+ T cells display central memory phenotype, efficiently kill target cells in vivo, and protect recipients against tumor growth in a preventive setting. Furthermore, we confirm previously published observation that high level engraftment of antigen-expressing HSCs following myeloablative conditioning results in tolerance and an absence of specific cytotoxic activity in vivo. In conclusion, the data presented here supports potential application of immunization by limited transplantation of antigen-expressing HSCs for the prevention and treatment of cancer and therapeutic immunization of chronic infectious diseases such as HIV-1/AIDS.

  17. Supplementary Material for: Polyglutamine toxicity in yeast induces metabolic alterations and mitochondrial defects

    KAUST Repository

    Papsdorf, Katharina

    2015-01-01

    Abstract Background Protein aggregation and its pathological effects are the major cause of several neurodegenerative diseases. In Huntingtonâ s disease an elongated stretch of polyglutamines within the protein Huntingtin leads to increased aggregation propensity. This induces cellular defects, culminating in neuronal loss, but the connection between aggregation and toxicity remains to be established. Results To uncover cellular pathways relevant for intoxication we used genome-wide analyses in a yeast model system and identify fourteen genes that, if deleted, result in higher polyglutamine toxicity. Several of these genes, like UGO1, ATP15 and NFU1 encode mitochondrial proteins, implying that a challenged mitochondrial system may become dysfunctional during polyglutamine intoxication. We further employed microarrays to decipher the transcriptional response upon polyglutamine intoxication, which exposes an upregulation of genes involved in sulfur and iron metabolism and mitochondrial Fe-S cluster formation. Indeed, we find that in vivo iron concentrations are misbalanced and observe a reduction in the activity of the prominent Fe-S cluster containing protein aconitase. Like in other yeast strains with impaired mitochondria, non-fermentative growth is impossible after intoxication with the polyglutamine protein. NMR-based metabolic analyses reveal that mitochondrial metabolism is reduced, leading to accumulation of metabolic intermediates in polyglutamine-intoxicated cells. Conclusion These data show that damages to the mitochondrial system occur in polyglutamine intoxicated yeast cells and suggest an intricate connection between polyglutamine-induced toxicity, mitochondrial functionality and iron homeostasis in this model system.

  18. A PILOT EXTERNAL QUALITY ASSURANCE STUDY OF TRANSFUSION SCREENING FOR HIV, HCV AND HBSAG IN TWELVE AFRICAN COUNTRIES

    Science.gov (United States)

    Bloch, Evan M; Shah, Avani; Kaidarova, Zhanna; Laperche, Syria; Lefrere, Jean-Jacques; van Hasselt, James; Zacharias, Peter; Murphy, Edward L

    2014-01-01

    Background and Objectives Serologic screening for the major transfusion transmissible viruses (TTV) is critical to blood safety and has been widely implemented. However, actual performance as measured by proficiency testing has not been well studied in Sub-Saharan Africa. Therefore, we conducted an external quality assessment of laboratories engaged in transfusion screening in the region. Materials and Methods Blinded test panels, each comprising 25 serum samples that were pedigreed for HIV, HBsAg, HCV and negative status, were sent to participating laboratories. The panels were tested using the laboratories’ routine donor screening methods and conditions. Sensitivity and specificity were calculated and multivariable analysis was used to compare performance against mode of testing, country and infrastructure. Results A total of 12 African countries and 44 laboratories participated in the study. The mean (range) sensitivities for HIV, HBsAg and HCV were 91.9% (14.3-100), 86.7% (42.9-100) and 90.1% (50-100), respectively. Mean specificities for HIV, HBsAg and HCV were 97.7%, 97% and 99.5% respectively. After adjusting for country and infrastructure, rapid tests had significantly lower sensitivity than enzyme immunoassays (EIA) for both HBsAg (p<0.0001) and HCV (p<0.05). Sensitivity also varied by country and selected infrastructure variables. Conclusion While specificity was high, sensitivity was more variable and deficient in a substantial number of testing laboratories. These findings underscore the importance of proficiency testing and quality control, particularly in Africa where TTV prevalence is high. PMID:25052195

  19. 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)

  20. Invariant NKT cells are required for airway inflammation induced by environmental antigens.

    Science.gov (United States)

    Wingender, Gerhard; Rogers, Paul; Batzer, Glenda; Lee, Myung Steve; Bai, Dong; Pei, Bo; Khurana, Archana; Kronenberg, Mitchell; Horner, Anthony A

    2011-06-06

    Invariant NKT cells (iNKT cells) are a unique subset of T lymphocytes that rapidly carry out effector functions. In this study, we report that a majority of sterile house dust extracts (HDEs) tested contained antigens capable of activating mouse and human iNKT cells. HDEs had adjuvant-like properties in an ovalbumin (OVA)-induced asthma model, which were dependent on Vα14i NKT cells, as vaccinated animals deficient for iNKT cells displayed significantly attenuated immune responses and airway inflammation. Furthermore, the administration of HDEs together with OVA mutually augmented the synthesis of cytokines by Vα14i NKT cells and by conventional CD4(+) T cells in the lung, demonstrating a profound immune response synergy for both Th2 cytokines and IL-17A. These data demonstrate that iNKT cell antigens are far more widely dispersed in the environment than previously anticipated. Furthermore, as the antigenic activity in different houses varied greatly, they further suggest that iNKT cell responses to ambient antigens, particular to certain environments, might promote sensitization to conventional respiratory allergens.

  1. Mutations induced by X-rays and UV radiation during the nuclear cycle in the yeast Schizosarccharomyces pombe

    International Nuclear Information System (INIS)

    Barale, R.; Rusciano, D.; Loprieno, N.

    1982-01-01

    The availability of a cell-division-cycle (cdc) mutant in the fission yeast S. pombe, wee 1-50, has made possible the production of a large population of G 1 nuclear-stage synchronized cells. During their development, yeast cells from the G 1 into the G 2 nuclear stages were treated with X-rays and UV radiation at various doses. The DNA pre-replicative and replicative phases were the most sensitive to both cell lethality and mutant induction with either X-rays or UV radiation. The trends of induced biological effects that were observed suggest that the induction of mutations is dependent on the number of unrepaired DNA lesions that reach the replicating fork or of those that occur at that time. The X-ray-induced mutations were earlier saturated, possibly because of the higher number of lethal lesions so induced. (orig.)

  2. 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.

  3. Analysis of mutagenic effects induced by carbon beams at different LET in a red yeast strain

    International Nuclear Information System (INIS)

    Sun Haining; Wang Jufang; Ma Shuang; Lu Dong; Wu Xin; Li Wenjian

    2011-01-01

    To evaluate inactive and mutagenic effects of carbon beam at different LET, the inactivation cross section and mutation cross section induced by carbon beams of different LET values were investigated in a red yeast strain Rhodotorula glutinis AY 91015. It was found that the maximum inactivation cross section of 4.37μm 2 , which was very close to the average nucleus cross section, was at LET of 120.0 keV/μm. The maximum mutation cross section was at LET of 96.0 keV/μm. Meanwhile, the highest mutagenicity of carbon ion was found around 58.2 keV/μm. It implied that the most efficient LET to induce mutation in survival yeasts was 58.2 keV/μm, which corresponded to energy of 35 MeV/u carbon beam. The most effective carbon beam to induce inactivation and mutation located at different energy region. (authors)

  4. Accelerating Yeast Prion Biology using Droplet Microfluidics

    Science.gov (United States)

    Ung, Lloyd; Rotem, Assaf; Jarosz, Daniel; Datta, Manoshi; Lindquist, Susan; Weitz, David

    2012-02-01

    Prions are infectious proteins in a misfolded form, that can induce normal proteins to take the misfolded state. Yeast prions are relevant, as a model of human prion diseases, and interesting from an evolutionary standpoint. Prions may also be a form of epigenetic inheritance, which allow yeast to adapt to stressful conditions at rates exceeding those of random mutations and propagate that adaptation to their offspring. Encapsulation of yeast in droplet microfluidic devices enables high-throughput measurements with single cell resolution, which would not be feasible using bulk methods. Millions of populations of yeast can be screened to obtain reliable measurements of prion induction and loss rates. The population dynamics of clonal yeast, when a fraction of the cells are prion expressing, can be elucidated. Furthermore, the mechanism by which certain strains of bacteria induce yeast to express prions in the wild can be deduced. Integrating the disparate fields of prion biology and droplet microfluidics reveals a more complete picture of how prions may be more than just diseases and play a functional role in yeast.

  5. FcepsilonRI-alpha siRNA inhibits the antigen-induced activation of mast cells.

    Science.gov (United States)

    Safaralizadeh, Reza; Soheili, Zahra-Soheila; Deezagi, Abdolkhaleg; Pourpak, Zahra; Samiei, Shahram; Moin, Mostafa

    2009-12-01

    FcepsilonRI, The high affinity receptor for IgE plays a critical role in triggering the allergic reactions. It is responsible for inducing mast cell degranulation and deliberation of allergy mediators when it is aggregated by allergen and IgE complexes. FcepsilonRI on the mast cells consists of three subunits; alpha chain directly binds IgE, beta chain and dimmer of gamma chains together mediate intracellular signaling. Cross-linking of IgE-bound FcepsilonRI on the surface of mast cells and basophils by the multivalent antigen induces release of chemical mediators. The present in vitro study was designed to investigate the effect of synthetic FcepsilonRI-alpha siRNA on the antigen-induced activation of MC/9 cells. MC/9 cells which are murine mast cells were transfected by FcepsilonRI-alpha siRNA and negative control siRNA. After 6 h, anti-DNP (Dinitrophenyl) IgE was used for the cells sensitization. Then the cells were challenged with Dinitrophenyl-Human Serum Albumin (DNP-HSA) for mast cell degranulation induction before collection of supernatants. The amount of mRNA and protein expression was measured by Real Time PCR and western blot analysis, respectively. Determination of the expression rate of FcepsilonRI-alpha on cell surface was achieved by flow cytometry. ELISA and spectrophotometry methods were used subsequently for measuring the effects of FcepsilonRI-alpha siRNA on antigen-induced histamine and beta-hexosaminidase release. FcepsilonRI-alpha siRNA treated cells showed significant decrease in FcepsilonRI-alpha mRNA and protein expression in comparison to control cells. FcepsilonRI-mediated mast cell release of beta-hexosaminidase and histamine were also inhibited. In this study it was shown that FcepsilonRI-alpha siRNA could suppress FcepsilonRI-alpha expression and inhibited degranulation and histamine release in antigen-stimulated MC/9 cells. In conclusion, knock-down of FcepsilonRI-alpha by siRNA could be a promising method for inhibition of the mast

  6. Conventional CD4+ T cells present bacterial antigens to induce cytotoxic and memory CD8+ T cell responses.

    Science.gov (United States)

    Cruz-Adalia, Aránzazu; Ramirez-Santiago, Guillermo; Osuna-Pérez, Jesús; Torres-Torresano, Mónica; Zorita, Virgina; Martínez-Riaño, Ana; Boccasavia, Viola; Borroto, Aldo; Martínez Del Hoyo, Gloria; González-Granado, José María; Alarcón, Balbino; Sánchez-Madrid, Francisco; Veiga, Esteban

    2017-11-17

    Bacterial phagocytosis and antigen cross-presentation to activate CD8 + T cells are principal functions of professional antigen presenting cells. However, conventional CD4 + T cells also capture and kill bacteria from infected dendritic cells in a process termed transphagocytosis (also known as transinfection). Here, we show that transphagocytic T cells present bacterial antigens to naive CD8 + T cells, which proliferate and become cytotoxic in response. CD4 + T-cell-mediated antigen presentation also occurs in vivo in the course of infection, and induces the generation of central memory CD8 + T cells with low PD-1 expression. Moreover, transphagocytic CD4 + T cells induce protective anti-tumour immune responses by priming CD8 + T cells, highlighting the potential of CD4 + T cells as a tool for cancer immunotherapy.

  7. Effect of sterol metabolism in the yeast-Drosophila system on the frequency of radiation-induced aneuploidy in the Drosophila melanogaster oocytes

    International Nuclear Information System (INIS)

    Savitskii, V.V.; Luchnikova, E.M.; Inge-Vechtomov, S.G.

    1986-01-01

    The effect of sterol metabolism on induced mutagenesis of Drosophila melanogaster was studied in the ecogenetic system of yeast-Drosophila. Sterol deficiency was created in Drosophila by using the biomass of live cells of Saccharomyces cerevisiae strain 9-2-P712 till mutation in locus nys/sup r1/ blocking the synthesis of ergosterol as the food. It was found that rearing of Drosophila females on the mutant yeast increases the frequency of loss and nondisjunction of X chromosomes induced in mature oocytes by X rays (1000 R). Addition of 0.1% of cholesterol solution in 10% ethanol to the yeast biomass restores the resistance of oocyte to X irradiation to the control level. The possible hormonal effect on membrane leading to increased radiation-induced aneuploidy in Drosophila and the role of sterol metabolism in determining the resistance to various damaging factors are discussed

  8. Precision cancer immunotherapy: optimizing dendritic cell-based strategies to induce tumor antigen-specific T-cell responses against individual patient tumors.

    Science.gov (United States)

    Osada, Takuya; Nagaoka, Koji; Takahara, Masashi; Yang, Xiao Yi; Liu, Cong-Xiao; Guo, Hongtao; Roy Choudhury, Kingshuk; Hobeika, Amy; Hartman, Zachary; Morse, Michael A; Lyerly, H Kim

    2015-05-01

    Most dendritic cell (DC)-based vaccines have loaded the DC with defined antigens, but loading with autologos tumor-derived antigens would generate DCs that activate personalized tumor-specific T-cell responses. We hypothesized that DC matured with an optimized combination of reagents and loaded with tumor-derived antigens using a clinically feasible electroporation strategy would induce potent antitumor immunity. We first studied the effects on DC maturation and antigen presentation of the addition of picibanil (OK432) to a combination of zoledronic acid, tumor necrosis factor-α, and prostaglandin E2. Using DC matured with the optimized combination, we tested 2 clinically feasible sources of autologous antigen for electroloading, total tumor mRNA or total tumor lysate, to determine which stimulated more potent antigen-specific T cells in vitro and activated more potent antitumor immunity in vivo. The combination of tumor necrosis factor-α/prostaglandin E2/zoledronic acid/OK432 generated DC with high expression of maturation markers and antigen-specific T-cell stimulatory function in vitro. Mature DC electroloaded with tumor-derived mRNA [mRNA electroporated dendritic cell (EPDC)] induced greater expansion of antigen-specific T cells in vitro than DC electroloaded with tumor lysate (lysate EPDC). In a therapeutic model of MC38-carcinoembryonic antigen colon cancer-bearing mice, vaccination with mRNA EPDC induced the most efficient anti-carcinoembryonic antigen cellular immune response, which significantly suppressed tumor growth. In conclusion, mature DC electroloaded with tumor-derived mRNA are a potent cancer vaccine, especially useful when specific tumor antigens for vaccination have not been identified, allowing autologous tumor, and if unavailable, allogeneic cell lines to be used as an unbiased source of antigen. Our data support clinical testing of this strategy.

  9. Isolation of the alkane inducible cytochrome P450 (P450alk) gene from the yeast Candida tropicalis

    Science.gov (United States)

    The gene for the alkane-inducible cytochrome P450, P450alk, has been isolated from the yeast Candida tropicalis by immunoscreening a λgt11 library. Isolation of the gene has been identified on the basis of its inducibility and partial DNA sequence. Transcripts of this gene were i...

  10. Yeast Interacting Proteins Database: YFR015C, YJL137C [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entr...pression induced by glucose limitation, nitrogen starvation, environmental stress, and entry into stationary

  11. Low prevalence of hepatitis B and C among tuberculosis patients in Duhok Province, Kurdistan: Are HBsAg and anti-HCV prerequisite screening parameters in tuberculosis control program?

    Science.gov (United States)

    Merza, Muayad A; Haji, Safer M; Alsharafani, Abid Mohialdeen Hasan; Muhammed, Shivan U

    2016-09-01

    Viral hepatitis, particularly hepatitis B virus (HBV) and hepatitis C virus (HCV), infections and tuberculosis (TB) are a global public health concern. Co-infection with HBV or HCV among TB patients may potentiate the risk of hepatotoxicity induced by anti-TB drugs. Hence, the aim of this study was to identify the prevalence of HBV and HCV among TB patients included in the Duhok National Tuberculosis Program (NTP). The Duhok NTP Center is a specialized institution in Duhok City, Iraq, concerned with management and follow-up of TB patients. A cross-sectional study was conducted at the center between June 2015 and May 2016. All documented TB patients were analyzed on the basis of socio-demographic and other characteristics. Thereafter, all patients underwent screening for hepatitis B surface antigen (HBsAg), anti-HCV, and anti-HIV using enzyme-linked immunosorbent assay (ELISA). The results obtained were analyzed by entering the data in binary format into a Microsoft Excel spreadsheet. A p value of Kurdistan, the negative history of injection drug use, and adherence to universal infection-control measures, including vaccination for HBV. Both history of dental intervention and belonging to a Syrian population were independent risk factors for HBV/TB co-infection. Copyright © 2016 Asian-African Society for Mycobacteriology. Published by Elsevier Ltd. All rights reserved.

  12. A Clinical study of HBsAg and Anti-HBs in the serum of patients with various liver diseases

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hak San; Kim, Jong Mann; Kim, Hwa Sook; Kim, Yul Ja; Lee, Hak Choong; Lee, Chong Suk [National Medical Center, Seoul (Korea, Republic of)

    1981-09-15

    Serum HBsAg and Anti-HBs obtained by radioimmunoassay were studied in 109 cases of various liver diseases who visited or were admitted to National Medical Center from December, 1980 to July, 1981. The results were as follows; 1) HBsAg was detected in 67.0% of total 109 cases; 71.9% of 32 cases with acute viral hepatitis, 71.4% of 14 cases with chronic hepatitis, 65.2% of 46 cases with liver cirrhosis and 58.8% of 17 cases with hepatoma. 2) Anti-HBs was detected in 32.1% of total 109 cases; 37.0% of 46 cases with liver cirrhosis, 29.4% of 17 cases with hepatoma, 28.6% of 14 cases with chronic hepatitis, 28.1% of 32 cases with acute viral hepatitis. 3) HBsAg or Anti-HBs, the markers of Hepatitis B virus was detected in 89.0% of total 109 cases; 93.6% of 32 cases with acute viral hepatitis, 89.1% of 46 cases with liver cirrhosis, 85.7% of 14 cases with chronic hepatitis and 82.4% of 17 cases with hepatoma, which strongly suggested that the various liver diseases were associated with hepatitis B virus infection.

  13. A Clinical study of HBsAg and Anti-HBs in the serum of patients with various liver diseases

    International Nuclear Information System (INIS)

    Kim, Hak San; Kim, Jong Mann; Kim, Hwa Sook; Kim, Yul Ja; Lee, Hak Choong; Lee, Chong Suk

    1981-01-01

    Serum HBsAg and Anti-HBs obtained by radioimmunoassay were studied in 109 cases of various liver diseases who visited or were admitted to National Medical Center from December, 1980 to July, 1981. The results were as follows; 1) HBsAg was detected in 67.0% of total 109 cases; 71.9% of 32 cases with acute viral hepatitis, 71.4% of 14 cases with chronic hepatitis, 65.2% of 46 cases with liver cirrhosis and 58.8% of 17 cases with hepatoma. 2) Anti-HBs was detected in 32.1% of total 109 cases; 37.0% of 46 cases with liver cirrhosis, 29.4% of 17 cases with hepatoma, 28.6% of 14 cases with chronic hepatitis, 28.1% of 32 cases with acute viral hepatitis. 3) HBsAg or Anti-HBs, the markers of Hepatitis B virus was detected in 89.0% of total 109 cases; 93.6% of 32 cases with acute viral hepatitis, 89.1% of 46 cases with liver cirrhosis, 85.7% of 14 cases with chronic hepatitis and 82.4% of 17 cases with hepatoma, which strongly suggested that the various liver diseases were associated with hepatitis B virus infection.

  14. K2 killer toxin-induced physiological changes in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Orentaite, Irma; Poranen, Minna M; Oksanen, Hanna M; Daugelavicius, Rimantas; Bamford, Dennis H

    2016-03-01

    Saccharomyces cerevisiae cells produce killer toxins, such as K1, K2 and K28, that can modulate the growth of other yeasts giving advantage for the killer strains. Here we focused on the physiological changes induced by K2 toxin on a non-toxin-producing yeast strain as well as K1, K2 and K28 killer strains. Potentiometric measurements were adjusted to observe that K2 toxin immediately acts on the sensitive cells leading to membrane permeability. This correlated with reduced respiration activity, lowered intracellular ATP content and decrease in cell viability. However, we did not detect any significant ATP leakage from the cells treated by killer toxin K2. Strains producing heterologous toxins K1 and K28 were less sensitive to K2 than the non-toxin producing one suggesting partial cross-protection between the different killer systems. This phenomenon may be connected to the observed differences in respiratory activities of the killer strains and the non-toxin-producing strain at low pH. This might also have practical consequences in wine industry; both as beneficial ones in controlling contaminating yeasts and non-beneficial ones causing sluggish fermentation. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Primary immunization-like response without hepatitis following transfusion of HBeAg-positive blood

    DEFF Research Database (Denmark)

    Gluud, C; Aldershvile, J; Kryger, P

    1983-01-01

    An accidental transfusion of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) positive whole blood was given to a 19-yr-old male, bleeding after tonsillectomy. Serum obtained from the patient before the transfusion revealed no hepatitis B antigens or antibodies. After...... the transfusion the patient became HBsAg-positive, cleared this antigen and developed antibodies to both HBsAg and HBeAg. The transfusion blood was positive for total antibody and IgM antibody to hepatitis B core antigen (HBcAg). The patient's blood became positive for these antibodies after the transfusion...

  16. 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

  17. Yeast modulation of human dendritic cell cytokine secretion: an in vitro study.

    Directory of Open Access Journals (Sweden)

    Ida M Smith

    Full Text Available Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The concept of individual microorganisms influencing the makeup of T cell subsets via interactions with intestinal dendritic cells (DCs appears to constitute the foundation for immunoregulatory effects of probiotics, and several studies have reported probiotic strains resulting in reduction of intestinal inflammation through modulation of DC function. Consequent to a focus on Saccharomyces boulardii as the fundamental probiotic yeast, very little is known about hundreds of non-Saccharomyces yeasts in terms of their interaction with the human gastrointestinal immune system. The aim of the present study was to evaluate 170 yeast strains representing 75 diverse species for modulation of inflammatory cytokine secretion by human DCs in vitro, as compared to cytokine responses induced by a S. boulardii reference strain with probiotic properties documented in clinical trials. Furthermore, we investigated whether cytokine inducing interactions between yeasts and human DCs are dependent upon yeast viability or rather a product of membrane interactions regardless of yeast metabolic function. We demonstrate high diversity in yeast induced cytokine profiles and employ multivariate data analysis to reveal distinct clustering of yeasts inducing similar cytokine profiles in DCs, highlighting clear species distinction within specific yeast genera. The observed differences in induced DC cytokine profiles add to the currently very limited knowledge of the cross-talk between yeasts and human immune cells and provide a foundation for selecting yeast strains for further characterization and development toward potentially novel yeast probiotics. Additionally, we present data to support a hypothesis that the interaction between yeasts and human DCs does not solely depend on yeast viability, a concept which may suggest a need for further classifications

  18. Yeast Modulation of Human Dendritic Cell Cytokine Secretion: An In Vitro Study

    Science.gov (United States)

    Smith, Ida M.; Christensen, Jeffrey E.; Arneborg, Nils; Jespersen, Lene

    2014-01-01

    Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The concept of individual microorganisms influencing the makeup of T cell subsets via interactions with intestinal dendritic cells (DCs) appears to constitute the foundation for immunoregulatory effects of probiotics, and several studies have reported probiotic strains resulting in reduction of intestinal inflammation through modulation of DC function. Consequent to a focus on Saccharomyces boulardii as the fundamental probiotic yeast, very little is known about hundreds of non-Saccharomyces yeasts in terms of their interaction with the human gastrointestinal immune system. The aim of the present study was to evaluate 170 yeast strains representing 75 diverse species for modulation of inflammatory cytokine secretion by human DCs in vitro, as compared to cytokine responses induced by a S. boulardii reference strain with probiotic properties documented in clinical trials. Furthermore, we investigated whether cytokine inducing interactions between yeasts and human DCs are dependent upon yeast viability or rather a product of membrane interactions regardless of yeast metabolic function. We demonstrate high diversity in yeast induced cytokine profiles and employ multivariate data analysis to reveal distinct clustering of yeasts inducing similar cytokine profiles in DCs, highlighting clear species distinction within specific yeast genera. The observed differences in induced DC cytokine profiles add to the currently very limited knowledge of the cross-talk between yeasts and human immune cells and provide a foundation for selecting yeast strains for further characterization and development toward potentially novel yeast probiotics. Additionally, we present data to support a hypothesis that the interaction between yeasts and human DCs does not solely depend on yeast viability, a concept which may suggest a need for further classifications beyond the current

  19. Comparison of antigen-specific T-cell responses of tuberculosis patients using complex or single antigens of Mycobacterium tuberculosis

    DEFF Research Database (Denmark)

    Mustafa, A S; Amoudy, H A; Wiker, H G

    1998-01-01

    GroES, rPstS, rGroEL and rDnaK) antigens of Mycobacterium tuberculosis. The responses of PBMC to these defined antigens were compared with the corresponding results obtained with complex antigens, such as whole-cell M. tuberculosis, M. tuberculosis culture filtrate (MT-CF) and cell wall antigens, as well...... as the vaccine strain, Mycobacterium bovis bacillus Calmette-Guerin (BCG). In addition, M. tuberculosis and MT-CF-induced T-cell lines were tested in the same assays against the panel of purified and complex antigens. The compiled data from PBMC and T-cell lines tested for antigen-induced proliferation and IFN...

  20. Factors Predicting HBsAg Seroclearance and Alanine Transaminase Elevation in HBeAg-Negative Hepatitis B Virus-Infected Patients with Persistently Normal Liver Function.

    Directory of Open Access Journals (Sweden)

    Tai-Long Chien

    Full Text Available A certain proportion of hepatitis B virus (HBV-infected patients with persistently normal alanine transaminase (ALT levels have significant fibrosis. Using liver stiffness measurements (Fibroscan® and laboratory data, including serum ALT, quantitative HBsAg (qHBsAg, and HBV DNA, we attempted to predict the natural histories of these patients.Non-cirrhotic HBeAg-negative chronic hepatitis B patients with persistently normal ALT were followed up prospectively with the end points of HBsAg seroclearance and ALT elevation above the upper limit of normal. The factors that were predictive of the end points were identified.A total of 235 patients with an average age of 48.1 +/- 10.7 years were followed up for 7 years. Eight patients (3.4% lost HBsAg, and 15 patients (6.4% experienced ALT elevation. The overall cumulative HBsAg seroclearances were 0.4%, 1.3% and 2.3% at years 1, 3 and 5, respectively. Regarding HBsAg seroclearance, the qHBsAg (< 30 IU/ml cutoff resulted in a hazard ratio (HR of 19.6 with a 95% confidence interval (CI of 2.2-166.7 (P = 0.008. The baseline ALT level (odd ratio (OR 1.075, 95% CI 1.020-1.132, P = 0.006 and a qHBsAg above 1000 IU/ml (3.7, 1.1-12.4, P = 0.032 were associated with ALT elevation. Limited to men, the baseline liver stiffness (1.6, 1.0-2.5, P = 0.031 and a qHBsAg above 1000 IU/ml (10.4, 2.1-52.4, P = 0.004 were factors that were independently associated with ALT elevation.A low qHBsAg level predicted HBsAg clearance. Baseline ALT and a qHBsAg above 1000 IU/ml were independent predictive factors for ALT elevation. Among the men, the independent predictive factors for ALT elevation were qHBsAg and liver stiffness.

  1. Effects of Selenium Yeast on Blood Glucose and Antioxidant Biomarkers in Cholesterol Fed Diet Induced Type 2 Diabetes Mellitus in Wistar Rats.

    Science.gov (United States)

    Tanko, Y; Jimoh, A; Ahmed, A; Adam, A; Ejeh, L; Mohammed, A; Ayo, J O

    2017-03-06

    Selenium is an antioxidant that prevents oxygen radical from damaging cells from chronic diseases that can develop from cell injury and inflammation such as diabetes mellitus. The aim of the study is to investigate the possible protective effect of selenium yeast on cholesterol diet induced type-2 diabetes mellitus and oxidative stress in rats. Twenty male wistar rats were divided in to four groups of five animals each: Group 1: (Negative control) received standard animal feed only, Group 2:  received cholesterol diet (CD) only, Group 3: received CD and 0.1 mg/kg selenium yeast orally, Group 4: Received CD and 0.2 mg/kg selenium yeast orally for six weeks. At the end of the study period, the animals were sacrificed and the serum samples were collected and evaluated for estimation of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). The results showed a significant decrease in blood glucose level in the groups  co-administered CD and selenium yeast when compared to CD group only. Antioxidant enzymes status recorded significant decrease in SOD, CAT and GPx activities in CD and selenium yeast administered when compared to CD group only. In Conclusion, Selenium yeast administrations prevent free radical formations which are potent inducer of diabetes mellitus.

  2. Commensal oral bacteria antigens prime human dendritic cells to induce Th1, Th2 or Treg differentiation.

    Science.gov (United States)

    Kopitar, A N; Ihan Hren, N; Ihan, A

    2006-02-01

    In various immunopathologic conditions, bacterial flora induce an immune response which results in inflammatory manifestations, e.g. periapical granuloma. Dendritic cells provide the main orchestration of specific immune responses. The aim of our study was to test the capacity of distinct oral bacterial antigens (prepared from Streptococcus mitis, Propionibacterium acnes, and Bacteroides spp.) to prime human dendritic cells for stimulation of the T-lymphocyte response. To assess the T-lymphocyte response, the expression of CD25, CD69, intracellular interferon gamma (cIFN-gamma), and intracellular interleukin 4 (cIL-4) was determined. Dendritic cells were prepared from leukocyte buffy coat from healthy blood donors. Monocytes were stimulated with IL-4 and GM-CSF and dendritic cells activated with bacterial lysates. Cell suspensions contained up to 90% dendritic cells, which represented 2-12% of the initial number of mononuclear cells. Lymphocyte subsets that developed in lymphocyte cultures after 1 week of stimulation were analyzed by flow cytometry. Dendritic cells, primed with antigens of Bacteroides fragilis have shown significantly higher activation and expression of intercellular IFN-gamma by T lymphocytes compared to negative controls. The dendritic cells primed with antigens of P. acnes had no effect on T-lymphocyte activation or cytokine production; instead they induced differentiation of T lymphocytes into CD25bright cells (regulatory T cells) with a potentially inhibitory effect on immune response. Dendritic cells primed with antigens of S. mitis induced increased expression of cIL-4. We conclude that commensal oral bacteria antigens prepared from B. fragilis, S. mitis, and P. acnes prime human dendritic cells to induce Th1, Th2, and T(reg) differentiation, respectively. This may advance our understanding of immunopathologic manifestations in the oral cavity and offer new possibilities for redirecting immune responses in mucosal vaccination.

  3. Prevalence of hepatitis B virus infection in out-patient alcoholics

    DEFF Research Database (Denmark)

    Gluud, C; Gluud, B; Aldershvile, J

    1984-01-01

    Sera from 192 out-patient alcoholics attending a clinic for the treatment of alcoholism were tested for hepatitis B surface antigen (HBsAg) and for antibodies to HBsAg and to hepatitis B core antigen (HBcAg). Three sera (1.5%) were positive for HBsAg. Of the remaining 189 alcoholics, 29 (15%) were...... positive for one or both antibodies. This prevalence is not significantly different from that found in 137 hospitalized HBsAg-negative patients with alcoholic liver disease (35/137 [26%] were positive for one or both antibodies). However, the prevalence of hepatitis B antibodies in out-patient alcoholics...

  4. Dynamic imaging of experimental Leishmania donovani-induced hepatic granulomas detects Kupffer cell-restricted antigen presentation to antigen-specific CD8 T cells.

    Directory of Open Access Journals (Sweden)

    Lynette Beattie

    2010-03-01

    Full Text Available Kupffer cells (KCs represent the major phagocytic population within the liver and provide an intracellular niche for the survival of a number of important human pathogens. Although KCs have been extensively studied in vitro, little is known of their in vivo response to infection and their capacity to directly interact with antigen-specific CD8(+ T cells. Here, using a combination of approaches including whole mount and thin section confocal microscopy, adoptive cell transfer and intra-vital 2-photon microscopy, we demonstrate that KCs represent the only detectable population of mononuclear phagocytes within granulomas induced by Leishmania donovani infection that are capable of presenting parasite-derived peptide to effector CD8(+ T cells. This restriction of antigen presentation to KCs within the Leishmania granuloma has important implications for the identification of new candidate vaccine antigens and for the design of novel immuno-therapeutic interventions.

  5. Ausab test - a radioimmunoassay in the solid phase for the detection of antibodies against HBsAg

    Energy Technology Data Exchange (ETDEWEB)

    Lange, W; Koehler, H; Apodaca, J [Bundesgesundheitsamt, Berlin (Germany, F.R.). Abt. fuer Virologie

    1974-01-01

    The suitability of a newly developed RIA (Ausab test, Abbott laboratories) for the detection of antibodies against the Hepatitis B (surface) antigen (HBsAg) has been tested on 1968 sera of blood donors. Reproducibility test and specificity test were included. During the examination the technique of the Ausab test was changed from the original one-step to the two-step procedure. With the one-step technique 431 of 1968 sera (21.9%) showed positive reactions. During the test problems concerning the differentiation between positive and negative results were encountered due to high unspecific binding of radioactivity. Positive sera were re-examined employing the two-step technique and only 77.4% of the previously positive reactions could be reproduced. 50 sera that were negative in the one-step test remained negative in the two-step test. Difficulties concerning nonspecific binding of radioactivity as observed with the one-step technique were not encountered with the two-step procedure. On 92 of the confirmed positive sera a specificity test was run and 90 (97.8%) proved to be specific. A calculated 16.5% of the blood donors in Berlin have to be considered as antibody carriers. Only 6 of the Ausab positive sera were found to give positive reactions in CEP. 3 sera that were initially positive in CEP could neither be confirmed in a repeated CEP nor in the Ausab test.

  6. Anti-hepatitis B core antigen testing with detection and characterization of occult hepatitis B virus by an in-house nucleic acid testing among blood donors in Behrampur, Ganjam, Orissa in southeastern India: implications for transfusion

    Directory of Open Access Journals (Sweden)

    Panigrahi Rajesh

    2010-08-01

    Full Text Available Abstract Background Occult hepatitis B virus (HBV infection might transmit viremic units into the public blood supply if only hepatitis B surface antigen (HBsAg testing is used for donor screening. Our aim was to evaluate the prevalence of occult HBV infection among the HBsAg negative/antiHBc positive donations from a highly HIV prevalent region of India. Methods A total of 729 HBsAg negative donor units were included in this study. Surface gene and precore region were amplified by in house nucleic acid test (NAT for detection of occult HBV infection and surface gene was analyzed after direct sequencing. Results A total of 220 (30.1% HBsAg negative donors were antiHBc positive, of them 66 (30% were HBV DNA positive by NAT. HBV DNA positivity among 164 antiHBc only group, was 27.1% and among 40 antiHBs positive group was 30.0%. HBV/D (93.3% was predominant and prevalence of both HBV/C and HBV/A was 3.3%. Single or multiple amino acids substitutions were found in 95% samples. Conclusion Thus, a considerable number of HBV infected donors remain undiagnosed, if only HBsAg is used for screening. Addition of antiHBc testing for donor screening, although will lead to rejection of a large number of donor units, will definitely eliminate HBV infected donations and help in reducing HBV transmission with its potential consequences, especially among the immunocompromised population. The HBV genetic diversity found in this donor population are in accordance with other parts of India.

  7. Anti-hepatitis B core antigen testing with detection and characterization of occult hepatitis B virus by an in-house nucleic acid testing among blood donors in Behrampur, Ganjam, Orissa in southeastern India: implications for transfusion.

    Science.gov (United States)

    Panigrahi, Rajesh; Biswas, Avik; Datta, Sibnarayan; Banerjee, Arup; Chandra, Partha K; Mahapatra, Pradip K; Patnaik, Bharat; Chakrabarti, Sekhar; Chakravarty, Runu

    2010-08-27

    Occult hepatitis B virus (HBV) infection might transmit viremic units into the public blood supply if only hepatitis B surface antigen (HBsAg) testing is used for donor screening. Our aim was to evaluate the prevalence of occult HBV infection among the HBsAg negative/antiHBc positive donations from a highly HIV prevalent region of India. A total of 729 HBsAg negative donor units were included in this study. Surface gene and precore region were amplified by in house nucleic acid test (NAT) for detection of occult HBV infection and surface gene was analyzed after direct sequencing. A total of 220 (30.1%) HBsAg negative donors were antiHBc positive, of them 66 (30%) were HBV DNA positive by NAT. HBV DNA positivity among 164 antiHBc only group, was 27.1% and among 40 antiHBs positive group was 30.0%. HBV/D (93.3%) was predominant and prevalence of both HBV/C and HBV/A was 3.3%. Single or multiple amino acids substitutions were found in 95% samples. Thus, a considerable number of HBV infected donors remain undiagnosed, if only HBsAg is used for screening. Addition of antiHBc testing for donor screening, although will lead to rejection of a large number of donor units, will definitely eliminate HBV infected donations and help in reducing HBV transmission with its potential consequences, especially among the immunocompromised population. The HBV genetic diversity found in this donor population are in accordance with other parts of India.

  8. The Yeast Environmental Stress Response Regulates Mutagenesis Induced by Proteotoxic Stress

    Science.gov (United States)

    Shor, Erika; Fox, Catherine A.; Broach, James R.

    2013-01-01

    Conditions of chronic stress are associated with genetic instability in many organisms, but the roles of stress responses in mutagenesis have so far been elucidated only in bacteria. Here, we present data demonstrating that the environmental stress response (ESR) in yeast functions in mutagenesis induced by proteotoxic stress. We show that the drug canavanine causes proteotoxic stress, activates the ESR, and induces mutagenesis at several loci in an ESR-dependent manner. Canavanine-induced mutagenesis also involves translesion DNA polymerases Rev1 and Polζ and non-homologous end joining factor Ku. Furthermore, under conditions of chronic sub-lethal canavanine stress, deletions of Rev1, Polζ, and Ku-encoding genes exhibit genetic interactions with ESR mutants indicative of ESR regulating these mutagenic DNA repair processes. Analyses of mutagenesis induced by several different stresses showed that the ESR specifically modulates mutagenesis induced by proteotoxic stress. Together, these results document the first known example of an involvement of a eukaryotic stress response pathway in mutagenesis and have important implications for mechanisms of evolution, carcinogenesis, and emergence of drug-resistant pathogens and chemotherapy-resistant tumors. PMID:23935537

  9. Yeast Interacting Proteins Database: YFR015C, YLR258W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entr...n synthase, similar to Gsy1p; expression induced by glucose limitation, nitrogen ...; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entry into statio...ogen synthase, similar to Gsy1p; expression induced by glucose limitation, nitrogen starvation, heat shock,

  10. The Phospholipid:Diacylglycerol Acyltransferase Lro1 Is Responsible for Hepatitis C Virus Core-Induced Lipid Droplet Formation in a Yeast Model System.

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    Shingo Iwasa

    Full Text Available Chronic infection with the hepatitis C virus frequently induces steatosis, which is a significant risk factor for liver pathogenesis. Steatosis is characterized by the accumulation of lipid droplets in hepatocytes. The structural protein core of the virus induces lipid droplet formation and localizes on the surface of the lipid droplets. However, the precise molecular mechanisms for the core-induced formation of lipid droplets remain elusive. Recently, we showed that the expression of the core protein in yeast as a model system could induce lipid droplet formation. In this study, we probed the cellular factors responsible for the formation of core-induced lipid-droplets in yeast cells. We demonstrated that one of the enzymes responsible for triglyceride synthesis, a phospholipid:diacylglycerol acyltransferase (Lro1, is required for the core-induced lipid droplet formation. While core proteins inhibit Lro1 degradation and alter Lro1 localization, the characteristic localization of Lro1 adjacent to the lipid droplets appeared to be responsible for the core-induced lipid droplet formation. RNA virus genomes have evolved using high mutation rates to maintain their ability to replicate. Our observations suggest a functional relationship between the core protein with hepatocytes and yeast cells. The possible interactions between core proteins and the endoplasmic reticulum membrane affect the mobilization of specific proteins.

  11. [Analysis of the main components of inner ear antigens inducing autoimmune Meniere's disease in guinea pigs].

    Science.gov (United States)

    Lu, Ling; Tan, Chang-Qiang; Cui, Yu-Gui; Ding, Gui-Peng; Ju, Xiao-Bin; Li, Yu-Jin; Cai, Wen-Jun

    2008-08-01

    To investigate the main components of inner ear antigens inducing autoimmune Meniere's disease (AIMD) in guinea pigs. The guinea pigs were immunized with isologous crude inner ear antigens (ICIEAg). Then, the hearing function was measured with auditory brainstem response (ABR), the vestibular function was measured with electronystagmography (including spontaneous nystagmus and caloric test), and inner ear histopathological changes were observed by inner ear celloidin section with haematoxylin-eosin staining and observed under light microscope. According to these results, the AIMD-model animals from non-AIMD-model ones were distinguished. The special antibodies against ICIEAg in sera were measured with ELISA. The antigen-antibody reactions against different components of ICIEAg were detected by Western blotting with sera of AIMD and non-AIMD guinea pigs respectively. Then, we analysed the contrast between them and found the main components of the ICIEAg that were positive reaction in AIMD guinea pigs and negative reaction in non-AIMD guinea pigs. The result of ELISA demonstrated that the sera of both the AIMD and non-AIMD guniea pigs contained the special antibodies against ICIEAg after immunized with ICIEAg. The difference of the amount of antibody against ICIEAg between AIMD guinea pig group and non-AIMD guinea pig group was not significant. Western blotting assay showed only the sera of AIMD guinea pig contained the antibodies against the specific antigens with the molecular of 68 000, 58 000, 42 000 and 28 000. ICIEAg contain many different components, the AIMD might only happen in the guinea pigs in which the special immunization against the main components that could induce this kind of disorder appeared. The inner ear antigens with molecular of 68 000, 58 000, 42 000 and 28 000 might be the main components inducing AIMD in guinea pigs.

  12. Immune-escape mutations and stop-codons in HBsAg develop in a large proportion of patients with chronic HBV infection exposed to anti-HBV drugs in Europe

    DEFF Research Database (Denmark)

    Colagrossi, Luna; Hermans, Lucas E; Salpini, Romina

    2018-01-01

    structure of HBV genome, some immune-escape mutations or stop-codons in HBsAg can derive from drug-resistance mutations in RT. This study is aimed at gaining insight in prevalence and characteristics of immune-associated escape mutations, and stop-codons in HBsAg in chronically HBV-infected patients...

  13. Isolated HBsAg positivity in a Mexican patient with newly diagnosed lupus nephritis

    Directory of Open Access Journals (Sweden)

    Guillermo Delgado-García

    2017-01-01

    Conclusions: Isolated HBsAg positivity may result from multiple causes, one of which is cross-reactivity. To the best of our knowledge, this is the first report of a false-positive reading using CMIA technique in an active lupus patient. It is reasonable to stress that lupus patients with a positive screening for HBV should undergo a confirmatory assay (such as genomic detection, since this diagnosis may have important therapeutic implications.

  14. Genetically modified anthrax lethal toxin safely delivers whole HIV protein antigens into the cytosol to induce T cell immunity

    Science.gov (United States)

    Lu, Yichen; Friedman, Rachel; Kushner, Nicholas; Doling, Amy; Thomas, Lawrence; Touzjian, Neal; Starnbach, Michael; Lieberman, Judy

    2000-07-01

    Bacillus anthrax lethal toxin can be engineered to deliver foreign proteins to the cytosol for antigen presentation to CD8 T cells. Vaccination with modified toxins carrying 8-9 amino acid peptide epitopes induces protective immunity in mice. To evaluate whether large protein antigens can be used with this system, recombinant constructs encoding several HIV antigens up to 500 amino acids were produced. These candidate HIV vaccines are safe in animals and induce CD8 T cells in mice. Constructs encoding gag p24 and nef stimulate gag-specific CD4 proliferation and a secondary cytotoxic T lymphocyte response in HIV-infected donor peripheral blood mononuclear cells in vitro. These results lay the foundation for future clinical vaccine studies.

  15. 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.

  16. The Ausab test - a radioimmunoassay in the solid phase for the detection of antibodies against HBsAg

    International Nuclear Information System (INIS)

    Lange, W.; Koehler, H.; Apodaca, J.

    1974-01-01

    The suitability of a newly developed RIA (Ausab test, Abbott laboratories) for the detection of antibodies against the Hepatitis B (surface) antigen (HBsAg) has been tested on 1968 sera of blood donors. Reproducibility test and specificity test were included. During the examination the technique of the Ausab test was changed from the original one-step to the two-step procedure. With the one-step technique 431 of 1968 sera (21.9%) showed positive reactions. During the test problems concerning the differentiation between positive and negative results were encountered due to high unspecific binding of radioactivity. Positive sera were re-examined employing the two-step technique and only 77.4% of the previously positive reactions could be reproduced. 50 sera that were negative in the one-step test remained negative in the two-step test. Difficulties concerning nonspecific binding of radioactivity as observed with the one-step technique were not encountered with the two-step procedure. On 92 of the confirmed positive sera a specificity test was run and 90 (97.8%) proved to be specific. A calculated 16.5% of the blood donors in Berlin have to be considered as antibody carriers. Only 6 of the Ausab positive sera were found to give positive reactions in CEP. 3 sera that were initially positive in CEP could neither be confirmed in a repeated CEP nor in the Ausab test. (orig.) [de

  17. In vivo evaluation of antipyretic effects of homoeopathic ultrahigh dilutions of Typhoidinum on baker's yeast-induced fever in comparison with Paracetamol

    Directory of Open Access Journals (Sweden)

    Saeed Ahmad

    2017-01-01

    Full Text Available Introduction: Homoeopathy is a widely used, controversial alternative system of medicine. It is assumed that homoeopathic medicines are slower in action and does not work in acute conditions such as ‘fever’. The study aims to estimate the effectiveness of some homoeopathic remedies in fever and to compare their effects with Paracetamol. Materials and Methods: Baker's yeast fever model of rabbits was used in the study. Rabbits were divided into four different groups (n = 6. Rectal temperature was measured before and after fever induction hourly. After fever induction, medicines were administered orally. Paracetamol and Typhoidinum in 200C and 1M potencies were given orally. ANOVA followed by post hoc test was used for statistical analysis of results. The results were considered statistically significant at P ≤ 0.05. Results: Fever was induced in all the rabbits after 4 h of baker's yeast administration. The results of the study revealed the significant effectiveness of Typhoidinum in 200C and 1M potencies in baker's yeast-induced fever (P = 0.05. Typhoidinum in both potencies showed less significant results as compared to Paracetamol. However, all the medicines’ effects were significant compared to the negative control. Conclusion: Typhoidinum 200C and 1M worked against baker's yeast-induced fever. However, the results were slower and less significant than Paracetamol that might be due to lack of similarity of remedy picture and disease picture.

  18. An inducible transgenic mouse model for immune mediated hepatitis showing clearance of antigen expressing hepatocytes by CD8+ T cells.

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    Marcin Cebula

    Full Text Available The liver has the ability to prime immune responses against neo antigens provided upon infections. However, T cell immunity in liver is uniquely modulated by the complex tolerogenic property of this organ that has to also cope with foreign agents such as endotoxins or food antigens. In this respect, the nature of intrahepatic T cell responses remains to be fully characterized. To gain deeper insight into the mechanisms that regulate the CD8+ T cell responses in the liver, we established a novel OVA_X_CreER(T2 mouse model. Upon tamoxifen administration OVA antigen expression is observed in a fraction of hepatocytes, resulting in a mosaic expression pattern. To elucidate the cross-talk of CD8+ T cells with antigen-expressing hepatocytes, we adoptively transferred K(b/OVA257-264-specific OT-I T cells to OVA_X_CreER(T2 mice or generated triple transgenic OVA_X CreER(T2_X_OT-I mice. OT-I T cells become activated in OVA_X_CreER(T2 mice and induce an acute and transient hepatitis accompanied by liver damage. In OVA_X_CreER(T2_X_OT-I mice, OVA induction triggers an OT-I T cell mediated, fulminant hepatitis resulting in 50% mortality. Surviving mice manifest a long lasting hepatitis, and recover after 9 weeks. In these experimental settings, recovery from hepatitis correlates with a complete loss of OVA expression indicating efficient clearance of the antigen-expressing hepatocytes. Moreover, a relapse of hepatitis can be induced upon re-induction of cured OVA_X_CreER(T2_X_OT-I mice indicating absence of tolerogenic mechanisms. This pathogen-free, conditional mouse model has the advantage of tamoxifen inducible tissue specific antigen expression that reflects the heterogeneity of viral antigen expression and enables the study of intrahepatic immune responses to both de novo and persistent antigen. It allows following the course of intrahepatic immune responses: initiation, the acute phase and antigen clearance.

  19. Forsythoside A exerts antipyretic effect on yeast-induced pyrexia mice via inhibiting transient receptor potential vanilloid 1 function

    Science.gov (United States)

    Liu, Cuiling; Su, Hongchang; Wan, Hongye; Qin, Qingxia; Wu, Xuan; Kong, Xiangying; Lin, Na

    2017-01-01

    Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel gated by noxious heat, playing major roles in thermoregulation. Forsythoside A (FT-A) is the most abundant phenylethanoid glycosides in Fructus Forsythiae, which has been prescribed as a medicinal herb for treating fever in China for a long history. However, how FT-A affects pyrexia and what is the underlying molecular mechanism remain largely unknown. Here we found that FT-A exerted apparent antipyretic effect through decreasing the levels of prostaglandin E2 (PGE2) and interleukin 8 (IL-8) in a dose-dependent fashion on the yeast induced pyrexia mice. Interestingly, FT-A significantly downregulated TRPV1 expression in the hypothalamus and dorsal root ganglion (DRG) of the yeast induced pyrexia mice. Moreover, FT-A inhibited IL-8 and PGE2 secretions, and calcium influx in the HEK 293T-TRPV1 cells after stimulated with capsaicin, the specific TRPV1 agonist. Further investigation of the molecular mechanisms revealed that FT-A treatment rapidly inhibited phosphorylation of extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK) and p38 in both yeast induced pyrexia mice and HEK 293T-TRPV1 cells. These results suggest that FT-A may serve as a potential antipyretic agent and the therapeutic action of Fructus Forsythiae on pyretic related disease is, in part, due to the FT-A activities. PMID:28123347

  20. N-acetyl cysteine protects against ionizing radiation-induced DNA damage but not against cell killing in yeast and mammals

    Energy Technology Data Exchange (ETDEWEB)

    Reliene, Ramune [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Department of Medicine, Center for Human Nutrition, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Pollard, Julianne M. [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Biomedical Physics Interdepartmental Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Sobol, Zhanna; Trouiller, Benedicte [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Gatti, Richard A. [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Schiestl, Robert H., E-mail: rschiestl@mednet.ucla.edu [Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Biomedical Physics Interdepartmental Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Department of Radiation Oncology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095 (United States); Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, Los Angeles, CA 90095 (United States)

    2009-06-01

    Ionizing radiation (IR) induces DNA strand breaks leading to cell death or deleterious genome rearrangements. In the present study, we examined the role of N-acetyl-L-cysteine (NAC), a clinically proven safe agent, for it's ability to protect against {gamma}-ray-induced DNA strand breaks and/or DNA deletions in yeast and mammals. In the yeast Saccharomyces cerevisiae, DNA deletions were scored by reversion to histidine prototrophy. Human lymphoblastoid cells were examined for the frequency of {gamma}-H2AX foci formation, indicative of DNA double strand break formation. DNA strand breaks were also measured in mouse peripheral blood by the alkaline comet assay. In yeast, NAC reduced the frequency of IR-induced DNA deletions. However, NAC did not protect against cell death. NAC also reduced {gamma}-H2AX foci formation in human lymphoblastoid cells but had no protective effect in the colony survival assay. NAC administration via drinking water fully protected against DNA strand breaks in mice whole-body irradiated with 1 Gy but not with 4 Gy. NAC treatment in the absence of irradiation was not genotoxic. These data suggest that, given the safety and efficacy of NAC in humans, NAC may be useful in radiation therapy to prevent radiation-mediated genotoxicity, but does not interfere with efficient cancer cell killing.

  1. Damage-induced ectopic recombination in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Kupiec, M; Steinlauf, R

    1997-06-09

    Mitotic recombination in the yeast Saccharomyces cerevisiae is induced when cells are irradiated with UV or X-rays, reflecting the efficient repair of damage by recombinational repair mechanisms. We have used multiply marked haploid strains that allow the simultaneous detection of several types of ectopic recombination events. We show that inter-chromosomal ectopic conversion of lys2 heteroalleles and, to a lesser extent, direct repeat recombination (DRR) between non-tandem repeats, are increased by DNA-damaging agents; in contrast, ectopic recombination of the naturally occurring Ty element is not induced. We have tested several hypotheses that could explain the preferential lack of induction of Ty recombination by DNA-damaging agents. We have found that the lack of induction cannot be explained by a cell cycle control or by an effect of the mating-type genes. We also found no role for the flanking long terminal repeats (LTRs) of the Ty in preventing the induction. Ectopic conversion, DRR, and forward mutation of artificial repeats show different kinetics of induction at various positions of the cell cycle, reflecting different mechanisms of recombination. We discuss the mechanistic and evolutionary aspects of these results.

  2. Generation of Recombinant Schmallenberg Virus Nucleocapsid Protein in Yeast and Development of Virus-Specific Monoclonal Antibodies

    Directory of Open Access Journals (Sweden)

    Justas Lazutka

    2014-01-01

    Full Text Available Schmallenberg virus (SBV, discovered in continental Europe in late 2011, causes mild clinical signs in adult ruminants, including diarrhoea and reduced milk yield. However, fetal infection can lead to severe malformation in newborn offspring. To develop improved reagents for SBV serology, a high-level yeast expression system was employed to produce recombinant SBV nucleocapsid (N protein. Recombinant SBV N protein was investigated as an antigen in SBV-specific IgG enzyme immunoassay and used for generation of monoclonal antibodies (MAbs. Yeast-expressed SBV N protein was reactive with anti-SBV IgG-positive cow serum specimens collected from different farms of Lithuania. After immunization of mice with recombinant SBV N protein, four MAbs were generated. The MAbs raised against recombinant SBV N protein reacted with native viral nucleocapsids in SBV-infected BHK cells by immunofluorescence assay. The reactivity of recombinant N protein with SBV-positive cow serum specimens and the ability of the MAbs to recognize virus-infected cells confirm the antigenic similarity between yeast-expressed SBV N protein and native viral nucleocapsids. Our study demonstrates that yeast expression system is suitable for high-level production of recombinant SBV N protein and provides the first evidence on the presence of SBV-specific antibodies in cow serum specimens collected in Lithuania.

  3. A meta-analysis of the antiviral activity of the HBV-specific immunotherapeutic TG1050 confirms its value over a wide range of HBsAg levels in a persistent HBV pre-clinical model.

    Science.gov (United States)

    Kratzer, Roland; Sansas, Benoît; Lélu, Karine; Evlachev, Alexei; Schmitt, Doris; Silvestre, Nathalie; Inchauspé, Geneviève; Martin, Perrine

    2018-02-01

    Pre-clinical models mimicking persistent hepatitis B virus (HBV) expression are seldom, do not capture all features of a human chronic infection and due to their complexity, are subject to variability. We report a meta-analysis of seven experiments performed with TG1050, an HBV-targeted immunotherapeutic, 1 in an HBV-persistent mouse model based on the transduction of mice by an adeno-associated virus coding for an infectious HBV genome (AAV-HBV). To mimic the clinical diversity seen in HBV chronically infected patients, AAV-HBV transduced mice displaying variable HBsAg levels were treated with TG1050. Overall mean percentages of responder mice, displaying decrease in important clinical parameters i.e. HBV-DNA (viremia) and HBsAg levels, were 52% and 51% in TG1050 treated mice, compared with 8% and 22%, respectively, in untreated mice. No significant impact of HBsAg level at baseline on response to TG1050 treatment was found. TG1050-treated mice displayed a significant shorter Time to Response (decline in viral parameters) with an Hazard Ratio (HR) of 8.3 for viremia and 2.6 for serum HBsAg. The mean predicted decrease for TG1050-treated mice was 0.5 log for viremia and 0.8 log for HBsAg, at the end of mice follow-up, compared to no decrease for viremia and 0.3 log HBsAg decrease for untreated mice. For mice receiving TG1050, a higher decline of circulating viremia and serum HBsAg level over time was detected by interaction term meta-analysis with a significant treatment effect (p = 0.002 and pHBV-persistent model mimicking clinical situations.

  4. [Control levels of Sin3 histone deacetylase for spontaneous and UV-induced mutagenesis in yeasts Saccharomyces cerevisiae].

    Science.gov (United States)

    Lebovka, I Iu; Kozhina, T N; Fedorova, I V; Peshekhonov, V T; Evstiukhina, T A; Chernenkov, A Iu; Korolev, V G

    2014-01-01

    SIN3 gene product operates as a repressor for a huge amount of genes in Saccharomyces cerevisiae. Sin3 protein with a mass of about 175 kDa is a member of the RPD3 protein complex with an assessed mass of greater than 2 million Da. It was previously shownthat RPD3 gene mutations influence recombination and repair processes in S. cerevisiae yeasts. We studied the impacts of the sin3 mutation on UV-light sensitivity and UV-induced mutagenesis in budding yeast cells. The deletion ofthe SIN3 gene causes weak UV-sensitivity of mutant budding cells as compared to the wild-type strain. These results show that the sin3 mutation decreases both spontaneous and UV-induced levels of levels. This fact is hypothetically related to themalfunction of ribonucleotide reductase activity regulation, which leads to a decrease in the dNTP pool and the inaccurate error-prone damage bypass postreplication repair pathway, which in turn provokes a reduction in the incidence of mutations.

  5. Immunogenicity and antigenicity of the recombinant EMA-1 protein of Theileria equi expressed in the yeast Pichia pastoris Imunogenicidade e antigenicidade da proteína recombinante EMA-1 de Theileria equi expressa em Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Leandro Q. Nizoli

    2009-06-01

    Full Text Available The equine piroplasmosis caused by Theileria equi is one of the most important parasitic diseases of the equine, causing damage to animal health and economic losses. In T. equi, 2 merozoite surface proteins, equi merozoite antigen EMA-1 and EMA-2, have been identified as the most immunodominant antigens. This suggests that these antigens might be used as immunobiological tools. The EMA-1 of Theileria equi was cloned and expressed in the yeast Pichia pastoris. The transformed yeast was grown at high cell density, expressing up to 389 mg.L-1 of recombinant protein. The protein was concentrated and detected in Dot blot. The recombinant product was antigenically similar to the native protein as determined using monoclonal antibodies, and polyclonal antibodies obtained from equines naturally infected with T. equi. The immunogenicity of rEMA-1 protein was demonstrated by IFAT using sera from recombinant-protein-immunized mice using aluminum hydroxide as adjuvant. All animals vaccinated with rEMA-1 developed a high specific antibody response. This results suggest that rEMA-1expressed in P. pastoris might be a strong candidate to be used as an antigen for immune diagnostics as well as a vaccine antigen.A piroplasmose equina causada por Theileria equi é uma das mais importantes doenças parasitárias de equídeos, causando danos a saúde animal e perdas econômicas. Em T. equi, 2 proteínas de superfície de merozoítos, equi merozoite antigen EMA-1 e EMA-2, têm sido identificadas como antígenos imunodominantes. Sugerindo que estes antígenos possam ser usados como produtos imunobiológicos. O gene EMA-1 de T. equi foi clonado e expressado na levedura Pichia pastoris. As leveduras transformadas foram cultivadas a altas densidades celulares expressando 389 mg.L-1 de proteína recombinante. A proteína foi concentrada e detectada em Dot blot. O produto recombinante foi antigenicamente similar à proteína nativa quando determinado usando anticorpo

  6. Reactivation of viral replication in anti-HBe positive chronic HBsAg carriers

    DEFF Research Database (Denmark)

    Krogsgaard, K; Aldershvile, J; Kryger, Peter

    1990-01-01

    Reactivation of hepatitis B virus replication was investigated in an unselected group of 44 HBV DNA negative, anti-HBe positive chronic HBsAg carriers. Twenty-five patients (54%) were intravenous drug addicts and 7 (16%) were male homosexuals. Sixteen patients had evidence of delta infection...... to an annual reactivation rate of 5%. Reactivation in four patients was detected by reversion to HBV DNA positivity only, whereas HBeAg/anti-HBe status remained unchanged. Two patients became both HBV DNA and HBeAg positive. None of the patients developed hepatitis-like symptoms and transaminase elevation...

  7. DNA immunization with fusion of CTLA-4 to hepatitis B virus (HBV core protein enhanced Th2 type responses and cleared HBV with an accelerated kinetic.

    Directory of Open Access Journals (Sweden)

    Ying Yin

    Full Text Available BACKGROUND: Typically, DNA immunization via the intramuscular route induces specific, Th1-dominant immune responses. However, plasmids expressing viral proteins fused to cytotoxic T lymphocyte antigen 4 (CTLA-4 primed Th2-biased responses and were able to induced effective protection against viral challenge in the woodchuck model. Thus, we addressed the question in the mouse model how the Th1/Th2 bias of primed immune responses by a DNA vaccine influences hepatitis B virus (HBV clearance. PRINCIPAL FINDINGS: Plasmids expressing HBV core protein (HBcAg or HBV e antigen and HBcAg fused to the extracellular domain of CTLA-4 (pCTLA-4-HBc, CD27, and full length CD40L were constructed. Immunizations of these DNA plasmids induced HBcAg-specific antibody and cytotoxic T-cell responses in mice, but with different characteristics regarding the titers and subtypes of specific antibodies and intensity of T-cell responses. The plasmid pHBc expressing HBcAg induced an IgG2a-dominant response while immunizations of pCTLA-4-HBc induced a balanced IgG1/IgG2a response. To assess the protective values of the immune responses of different characteristics, mice were pre-immunized with pCTLA-4-HBc and pHBc, and challenged by hydrodynamic injection (HI of pAAV/HBV1.2. HBV surface antigen (HBsAg and DNA in peripheral blood and HBcAg in liver tissue were cleared with significantly accelerated kinetics in both groups. The clearance of HBsAg was completed within 16 days in immunized mice while more than 50% of the control mice are still positive for HBsAg on day 22. Stronger HBcAg-specific T-cell responses were primed by pHBc correlating with a more rapid decline of HBcAg expression in liver tissue, while anti-HBs antibody response developed rapidly in the mice immunized with pCTLA-4-HBc, indicating that the Th1/Th2 bias of vaccine-primed immune responses influences the mode of viral clearance. CONCLUSION: Viral clearance could be efficiently achieved by Th1/Th2-balanced

  8. Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens

    Science.gov (United States)

    Under physiological conditions the gut-associated lymphoid tissues not only prevent the induction of a local inflammatory immune response, but also induce systemic tolerance to fed antigens. A notable exception is coeliac disease, where genetically susceptible individuals expressing human leukocyte...

  9. Effect of salt hyperosmotic stress on yeast cell viability

    Directory of Open Access Journals (Sweden)

    Logothetis Stelios

    2007-01-01

    Full Text Available During fermentation for ethanol production, yeasts are subjected to different kinds of physico-chemical stresses such as: initially high sugar concentration and low temperature; and later, increased ethanol concentrations. Such conditions trigger a series of biological responses in an effort to maintain cell cycle progress and yeast cell viability. Regarding osmostress, many studies have been focused on transcriptional activation and gene expression in laboratory strains of Saccharomyces cerevisiae. The overall aim of this present work was to further our understanding of wine yeast performance during fermentations under osmotic stress conditions. Specifically, the research work focused on the evaluation of NaCl-induced stress responses of an industrial wine yeast strain S. cerevisiae (VIN 13, particularly with regard to yeast cell growth and viability. The hypothesis was that osmostress conditions energized specific genes to enable yeast cells to survive under stressful conditions. Experiments were designed by pretreating cells with different sodium chloride concentrations (NaCl: 4%, 6% and 10% w/v growing in defined media containing D-glucose and evaluating the impact of this on yeast growth and viability. Subsequent fermentation cycles took place with increasing concentrations of D-glucose (20%, 30%, 40% w/v using salt-adapted cells as inocula. We present evidence that osmostress induced by mild salt pre-treatments resulted in beneficial influences on both cell viability and fermentation performance of an industrial wine yeast strain.

  10. 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.

  11. Alkylglycerols modulate the proliferation and differentiation of non-specific agonist and specific antigen-stimulated splenic lymphocytes.

    Directory of Open Access Journals (Sweden)

    Linxi Qian

    Full Text Available Alkylglycerols (AKGs are ether-linked glycerols derived from shark liver oil and found in small amounts in human milk. Previous studies showed that oral AKGs administration significantly increased the immune response in mice. The aim of the present study was to investigate the in vitro immunomodulatory effect of AKGs on stimulating splenic lymphocyte responses. C57BL/6 mice were immunized with hepatitis B surface antigen (HBsAg. Splenic B cells were purified and stimulated with anti-BCR and anti-CD38. Meanwhile, splenic CD4+ T cells were purified and stimulated with anti-CD3 and anti-CD28. For antigen specific stimulation, the purified CD4+ T cells were cocultured with HBsAg -pulsed dendritic cells. The stimulated lymphocytes were treated with different concentrations of AKGs. The cell proliferation was assessed by [3H]-thymidine incorporation assay. The maturation of B cells was assessed by examining the germline (GL transcription of IgG (γ1 mRNA expression, and the surface expressions of CD80/CD86 markers were examined by flow cytometry analysis. Th1/Th2 polarity was assessed by T-BET (Th1/GATA-3 (Th2 flow cytometry assay and by characteristic cytokines ELISA assay (TNF-α and IFN-γ for Th1; IL-4 and IL-10 for Th2. It was found that AKGs significantly increased the BCR/CD38 -stimulated B cell proliferation. The T cell proliferation in response to CD3/CD28 or specific antigen stimulation was also increased by AKGs. The transcriptional level of IgG (γ1 and the expressions of CD80/CD86 molecules were markedly increased by AKGs in BCR/CD38 -stimulated B cells. Meanwhile, the results showed that AKGs increased the expression of T-BET transcriptional factor and the production of Th1 cytokines (TNF-α and IFN-γ upon CD3/CD28 stimulation; whereas, levels of Th2 cytokines (IL-4 and IL-10 were decreased by AKGs. Our study demonstrated that AKGs can modulate immune responses by boosting the proliferation and maturation of murine lymphocytes in vitro.

  12. Combining Phage and Yeast Cell Surface Antibody Display to Identify Novel Cell Type-Selective Internalizing Human Monoclonal Antibodies.

    Science.gov (United States)

    Bidlingmaier, Scott; Su, Yang; Liu, Bin

    2015-01-01

    Using phage antibody display, large libraries can be generated and screened to identify monoclonal antibodies with affinity for target antigens. However, while library size and diversity is an advantage of the phage display method, there is limited ability to quantitatively enrich for specific binding properties such as affinity. One way of overcoming this limitation is to combine the scale of phage display selections with the flexibility and quantitativeness of FACS-based yeast surface display selections. In this chapter we describe protocols for generating yeast surface antibody display libraries using phage antibody display selection outputs as starting material and FACS-based enrichment of target antigen-binding clones from these libraries. These methods should be widely applicable for the identification of monoclonal antibodies with specific binding properties.

  13. Recognition of oxidized albumin and thyroid antigens by psoriasis autoantibodies. A possible role of reactive-oxygen-species induced epitopes in chronic plaque psoriasis

    Directory of Open Access Journals (Sweden)

    Hani A. Al-Shobaili

    2015-12-01

    Full Text Available Objectives: To investigate the role of reactive-oxygen-species (ROS induced epitopes on human-serum-albumin (HSA and thyroid antigens in psoriasis autoimmunity. Methods: This study was performed in the College of Medicine, Qassim University, Buraidah, Saudi Arabia between May 2014 and February 2015. The study was designed to explore the role of ROS-induced epitopes in psoriasis autoimmunity. Singlet-oxygen (or ROS-induced epitopes on protein (ROS-epitopes-albumin was characterized by in-vitro and in-vivo. Thyroid antigens were prepared from rabbit thyroid, and thyroglobulin was isolated from thyroid extract. Immunocross-reactions of protein-A purified anti-ROS-epitopes-HSA-immunoglobulin G (IgGs with thyroid antigen, thyroglobulin, and their oxidized forms were determined. Binding characteristics of autoantibodies in chronic plaque psoriasis patients (n=26 against ROS-epitopes-HSA and also with native and oxidized thyroid antigens were screened, and the results were compared with age-matched controls (n=22. Results: The anti-ROS-epitopes-HSA-IgGs showed cross-reactions with thyroid antigen, thyroglobulin and with their oxidized forms. High degree of specific binding by psoriasis IgGs to ROS-epitopes-HSA, ROS-thyroid antigen and ROS-thyroglobulin was observed. Immunoglobulin G from normal-human-controls showed negligible binding with all tested antigens. Moreover, sera from psoriasis patients had higher levels of carbonyl contents compared with control sera. Conclusion: Structural alterations in albumin, thyroid antigens by ROS, generate unique neo-epitopes that might be one of the factors for the induction of autoantibodies in psoriasis.

  14. [Destruction of synovial pannus of antigen-induced arthritis by ultrasonic cavitation in rabbits].

    Science.gov (United States)

    Zhang, Ling-yan; Qiu, Li; Wang, Lei; Lin, Ling; Wen, Xiao-rong

    2011-11-01

    To optimize the conditions of ultrasonic irradiation and microbubble of ultrasound cavitation on destruction of synovial pannus of antigen-induced arthritis (AIA) in rabbits. Antigen-induced arthritis was successfully induced on bilateral knee joints of 85 rabbits. Each 10 AIA rabbits were divided into two groups to compare various peak negative pressures, different ultrasonic pulse durations, various pulse repetition frequencies, different irradiance duration, different dosages of microbubble contrast agents, different ultrasonic irradiance times. With intravenous infusion of Sonovue to the rabbits, ultrasonic irradiance was performed on the right knee joint using the above condition of ultrasound cavitation. At the day 1 after ultrasonic irradiance, MRI and pathological examination were employed to evaluate the optimal conditions. The optimal parameters and conditions for ultrasonic irradiance included intermittent ultrasonic application (in 6 s intervals), 0.6 mL/kg of microbubble contrast agent, 4.6 MPa of ultrasonic peak negative pressure, 100 cycles of pulse duration, 50 Hz of pulse repetition frequency, 5 min of ultrasonic duration, 0.6 mL/kg of dosages of microbubble contrast agents and multi-sessional ultrasonic irradiance. After the ultrasonic irradiance, the thickness of right knee synovium measured by MRI was thinner than that of left knee and synovial necrosis was confirmed by the pathological finding. Under optimal ultrasonic irradiation and microbubble conditions, ultrasonic cavitation could destroy synovial pannus of AIA in rabbits.

  15. Exploiting the yeast L-A viral capsid for the in vivo assembly of chimeric VLPs as platform in vaccine development and foreign protein expression.

    Directory of Open Access Journals (Sweden)

    Frank Powilleit

    Full Text Available A novel expression system based on engineered variants of the yeast (Saccharomyces cerevisiae dsRNA virus L-A was developed allowing the in vivo assembly of chimeric virus-like particles (VLPs as a unique platform for a wide range of applications. We show that polypeptides fused to the viral capsid protein Gag self-assemble into isometric VLP chimeras carrying their cargo inside the capsid, thereby not only effectively preventing proteolytic degradation in the host cell cytosol, but also allowing the expression of a per se cytotoxic protein. Carboxyterminal extension of Gag by T cell epitopes from human cytomegalovirus pp65 resulted in the formation of hybrid VLPs that strongly activated antigen-specific CD8(+ memory T cells ex vivo. Besides being a carrier for polypeptides inducing antigen-specific immune responses in vivo, VLP chimeras were also shown to be effective in the expression and purification of (i a heterologous model protein (GFP, (ii a per se toxic protein (K28 alpha-subunit, and (iii a particle-associated and fully recyclable biotechnologically relevant enzyme (esterase A. Thus, yeast viral Gag represents a unique platform for the in vivo assembly of chimeric VLPs, equally attractive and useful in vaccine development and recombinant protein production.

  16. Screening Immunomodulators To Skew the Antigen-Specific Autoimmune Response.

    Science.gov (United States)

    Northrup, Laura; Sullivan, Bradley P; Hartwell, Brittany L; Garza, Aaron; Berkland, Cory

    2017-01-03

    Current therapies to treat autoimmune diseases often result in side effects such as nonspecific immunosuppression. Therapies that can induce antigen-specific immune tolerance provide an opportunity to reverse autoimmunity and mitigate the risks associated with global immunosuppression. In an effort to induce antigen-specific immune tolerance, co-administration of immunomodulators with autoantigens has been investigated in an effort to reprogram autoimmunity. To date, identifying immunomodulators that may skew the antigen-specific immune response has been ad hoc at best. To address this need, we utilized splenocytes obtained from mice with experimental autoimmune encephalomyelitis (EAE) in order to determine if certain immunomodulators may induce markers of immune tolerance following antigen rechallenge. Of the immunomodulatory compounds investigated, only dexamethasone modified the antigen-specific immune response by skewing the cytokine response and decreasing T-cell populations at a concentration corresponding to a relevant in vivo dose. Thus, antigen-educated EAE splenocytes provide an ex vivo screen for investigating compounds capable of skewing the antigen-specific immune response, and this approach could be extrapolated to antigen-educated cells from other diseases or human tissues.

  17. Increased heme synthesis in yeast induces a metabolic switch from fermentation to respiration even under conditions of glucose repression.

    Science.gov (United States)

    Zhang, Tiantian; Bu, Pengli; Zeng, Joey; Vancura, Ales

    2017-10-13

    Regulation of mitochondrial biogenesis and respiration is a complex process that involves several signaling pathways and transcription factors as well as communication between the nuclear and mitochondrial genomes. Under aerobic conditions, the budding yeast Saccharomyces cerevisiae metabolizes glucose predominantly by glycolysis and fermentation. We have recently shown that altered chromatin structure in yeast induces respiration by a mechanism that requires transport and metabolism of pyruvate in mitochondria. However, how pyruvate controls the transcriptional responses underlying the metabolic switch from fermentation to respiration is unknown. Here, we report that this pyruvate effect involves heme. We found that heme induces transcription of HAP4 , the transcriptional activation subunit of the Hap2/3/4/5p complex, required for growth on nonfermentable carbon sources, in a Hap1p- and Hap2/3/4/5p-dependent manner. Increasing cellular heme levels by inactivating ROX1 , which encodes a repressor of many hypoxic genes, or by overexpressing HEM3 or HEM12 induced respiration and elevated ATP levels. Increased heme synthesis, even under conditions of glucose repression, activated Hap1p and the Hap2/3/4/5p complex and induced transcription of HAP4 and genes required for the tricarboxylic acid (TCA) cycle, electron transport chain, and oxidative phosphorylation, leading to a switch from fermentation to respiration. Conversely, inhibiting metabolic flux into the TCA cycle reduced cellular heme levels and HAP4 transcription. Together, our results indicate that the glucose-mediated repression of respiration in budding yeast is at least partly due to the low cellular heme level. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Improved humoral and cellular immune response against the gp120 V3 loop of HIV-1 following genetic immunization with a chimeric DNA vaccine encoding the V3 inserted into the hepatites B surface antigen

    DEFF Research Database (Denmark)

    Fomsgaard, A.; Nielsen, H.V.; Bryder, K.

    1998-01-01

    response and a uniform strong anti-HBs CTL response already 1 week p.i. in all mice. DNA vaccination with the chimeric MN V2/HBsAg plasmid elicited humoral responses against both viruses within 3-6 weeks which peaked at 6-12 weeks and remained stable for at least 25 weeks. In addition, specific CTL...... responses were induced in all mice against both MN V3 and HBsAg already within the first 3 weeks, lasting at least 11 weeks. Thus, HBsAg acts as a `genetic vaccine adjuvant' augmenting and accelerating the cellular and humoral immune response against the inserted MN V3 loop. Such chimeric HIV-HbsAg plasmid...

  19. Improved humoral and cellular immune responses against the gp120 V3 loop of HIV-1 following genetic immunization with a chimeric DNA vaccine encoding the V3 inserted into the hepatitis B surface antigen

    DEFF Research Database (Denmark)

    Fomsgaard, A; Nielsen, H V; Bryder, K

    1998-01-01

    response and a uniform strong anti-HBs CTL response already 1 week p.i. in all mice. DNA vaccination with the chimeric MN V3/HBsAg plasmid elicited humoral responses against both viruses within 3-6 weeks which peaked at 6-12 weeks and remained stable for at least 25 weeks. In addition, specific CTL...... responses were induced in all mice against both MN V3 and HBsAg already within the first 3 weeks, lasting at least 11 weeks. Thus, HBsAg acts as a 'genetic vaccine adjuvant' augmenting and accelerating the cellular and humoral immune response against the inserted MN V3 loop. Such chimeric HIV-HBsAg plasmid...

  20. Comparison of antigen-specific T-cell responses of tuberculosis patients using complex or single antigens of Mycobacterium tuberculosis

    DEFF Research Database (Denmark)

    Mustafa, A S; Amoudy, H A; Wiker, H G

    1998-01-01

    We have screened peripheral blood mononuclear cells (PBMC) from tuberculosis (TB) patients for proliferative reactivity and interferon-gamma (IFN-gamma) secretion against a panel of purified recombinant (r) and natural (n) culture filtrate (rESAT-6, nMPT59, nMPT64 and nMPB70) and somatic-derived (r......GroES, rPstS, rGroEL and rDnaK) antigens of Mycobacterium tuberculosis. The responses of PBMC to these defined antigens were compared with the corresponding results obtained with complex antigens, such as whole-cell M. tuberculosis, M. tuberculosis culture filtrate (MT-CF) and cell wall antigens, as well...... as the vaccine strain, Mycobacterium bovis bacillus Calmette-Guerin (BCG). In addition, M. tuberculosis and MT-CF-induced T-cell lines were tested in the same assays against the panel of purified and complex antigens. The compiled data from PBMC and T-cell lines tested for antigen-induced proliferation and IFN...

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

    Directory of Open Access Journals (Sweden)

    Ewoud Bernardus Compeer

    2012-03-01

    Full Text Available The cross-presentation of endocytosed antigen as peptide/class I MHC complexes plays a central role in the elicitation of CD8+ T cell clones that mediate anti-viral and anti-tumor immune responses. While it has been clear that there are specific subsets of professional antigen presenting cells (APC capable of antigen cross-presentation, description of mechanisms involved is still ongoing. Especially amongst dendritic cells (DC, there are specialized subsets that are highly proficient at antigen cross-presentation. We here present a focused survey on the cell biological processes in the endosomal pathway that support antigen cross-presentation. This review highlight DC-intrinsic mechanisms that facilitate the cross-presentation of endocytosed antigen, including receptor-mediated uptake, recycling and maturation including the sorting of membrane proteins, dynamic remodeling of endosomal structures and cell-surface directed endosomal trafficking. We will conclude with description of pathogen-induced deviation of endosomal processing, and discuss how immune evasion strategies pertaining endosomal trafficking may preclude antigen cross-presentation.

  2. The Ausab test - a radioimmunoassay in the solid phase for the detection of antibodies against HBsAg

    International Nuclear Information System (INIS)

    Lange, W.; Koehler, H.; Apodaca, J.

    1974-01-01

    The suitability of a newly developed RIA (Ausab test, Abbott Laboratories) for the detection of antibodies against the Hepatitis B (surface) antigen (HBsAg) has been tested on 1,968 sera of blood donors. Reproducibility test and specificity test were included. During the examination the technique of the Ausab test was changed from the original one-step to the two-step procedure. With the one-step technique 431 of 1,968 sera (21.9%) showed positive reactions. During the test problems concerning the differentiation between positive and negative results were encountered due to high unspecific binding of radioactivity. Positive sera were reexamined employing the two-step technique and only 77.4% of the previously positive reactions could be reproduced. 50 sera that were negative in the one-step test remained negative in the two-step test. Difficulties concerning nonspecific binding of radioactivity as observed with the one-step technique were not ecountered with the two-step procedure. On 92 of the confirmed positive sera a specificity test was run and 90 (97.8%) proved to be specific. A calculated 16.5% of the blood donors in Berlin have to be considered as antibody carriers. Only 6 of the Ausab positive sera were found to give positive reactions in CEP. 3 sera that were initially positive in CEP could neither be confirmed in a repeated CEP nor in the Ausab test. (orig.) [de

  3. 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...

  4. Assessment of side effects induced by injection of different adjuvant/antigen combinations in rabbits and mice

    NARCIS (Netherlands)

    Leenaars, P.P.A.M.; Koedam, M.A.; Wester, P.W.; Baumans, V.; Claassen, E.; Hendriksen, C.F.M.

    1998-01-01

    We evaluated the side effects induced by injection of Freund's adjuvant (FA) and alternative adjuvants combined with different antigens. Rabbits and mice were injected subcutaneously, intramuscularly (rabbits) and intraperitoneally (mice) with different adjuvants (FA, Specol, RIBI, TiterMax,

  5. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    International Nuclear Information System (INIS)

    Wang Jufang; Lu Dong; Wu Xin; Sun Haining; Ma Shuang; Li Renmin; Li Wenjian

    2010-01-01

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV μm -1 ) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV μm -1 . The mutation cross section saturated when LET was higher than 58.2 keV μm -1 . Meanwhile, the highest RBE i for inactivation located at 120.0 keV μm -1 and the highest RBE m for mutation was at 58.2 keV μm -1 . The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  6. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    Science.gov (United States)

    Wang, Jufang; Lu, Dong; Wu, Xin; Sun, Haining; Ma, Shuang; Li, Renmin; Li, Wenjian

    2010-09-01

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV μm -1) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV μm -1. The mutation cross section saturated when LET was higher than 58.2 keV μm -1. Meanwhile, the highest RBE i for inactivation located at 120.0 keV μm -1 and the highest RBE m for mutation was at 58.2 keV μm -1. The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  7. 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.)

  8. Efficacy of selective antenatal screening for hepatitis B among pregnant women in Denmark: is selective screening still an acceptable strategy in a low-endemicity country?

    DEFF Research Database (Denmark)

    Jensen, Lise; Heilmann, Carsten; Smith, Else

    2003-01-01

    The prevalence of hepatitis B virus (HBV) carriage in Denmark is unknown, but expected to be low (0.1%). This study aimed to evaluate the efficacy of selective antenatal screening for HBV infection and the epidemiology of HBV and hepatitis C virus (HCV) among pregnant women. 4098 women were...... included in the study. Blood tests were examined for hepatitis B surface antigen (HBsAg), anti-hepatitis B core antigen (HBc) and anti-HCV. Case records were studied to evaluate whether patients at risk for HBV infection had been tested. Among the 4098 women, 18 10.4%, 95% confidence interval (95% CI) 0.......3-0.71 were HBsAg positive. All had a risk factor for HBV infection. Only 13 (72%) were identified as HBsAg positive in the selective screening programme. 115 women (2.8%, 95% CI 2.3-3.4) were anti-HBc positive only. 95 (83%) were at risk for HBV. Only 72 of these (63%) were tested for HBsAg. The screening...

  9. Carbonation acceleration of calcium hydroxide nanoparticles: induced by yeast fermentation

    Science.gov (United States)

    Lopez-Arce, Paula; Zornoza-Indart, Ainara

    2015-09-01

    Carbonation of Ca(OH)2 nanoparticles and consolidation of limestone are accelerated by high humidity and a yeast fermentation system that supplies a saturated atmosphere on CO2, H2O vapor and ethanol during 28 days. Nanoparticles were analyzed by X-ray diffraction and differential thermal analyses with thermogravimetry. Spectrophotometry, scanning electron microscopy analyses, and hydric and mechanical tests were also performed in stones specimens. Samples exposed to the yeast environment achieve 100 % relative CaCO3 yield, whereas at high humidity but without the yeast and under laboratory environment, relative yields of 95 % CaCO3 and 15 % CaCO3 are, respectively, reached, with white crusts and glazing left on the stone surfaces when the nanoparticles are applied at a concentration of 25 g/l. The largest increase in the drilling resistance and surface hardness values with slight increase in the capillarity absorption and desorption coefficients and with lesser stone color changes are produced at a concentration of 5 g/l, in the yeast system environment. This especially happens in stone specimens initially with bimodal pore size distributions, more amounts of pores with diameters between 0.1 and 1 µm, higher open porosity values and faster capillary coefficients. An inexpensive and reliable method based on water and yeast-sugar solution is presented to speed up carbonation of Ca(OH)2 nanoparticles used as a consolidating product to improve the mechanical properties of decayed limestone from archaeological and architectural heritage.

  10. An improved yeast transformation method for the generation of very large human antibody libraries.

    Science.gov (United States)

    Benatuil, Lorenzo; Perez, Jennifer M; Belk, Jonathan; Hsieh, Chung-Ming

    2010-04-01

    Antibody library selection by yeast display technology is an efficient and highly sensitive method to identify binders to target antigens. This powerful selection tool, however, is often hampered by the typically modest size of yeast libraries (approximately 10(7)) due to the limited yeast transformation efficiency, and the full potential of the yeast display technology for antibody discovery and engineering can only be realized if it can be coupled with a mean to generate very large yeast libraries. We describe here a yeast transformation method by electroporation that allows for the efficient generation of large antibody libraries up to 10(10) in size. Multiple components and conditions including CaCl(2), MgCl(2), sucrose, sorbitol, lithium acetate, dithiothreitol, electroporation voltage, DNA input and cell volume have been tested to identify the best combination. By applying this developed protocol, we have constructed a 1.4 x 10(10) human spleen antibody library essentially in 1 day with a transformation efficiency of 1-1.5 x 10(8) transformants/microg vector DNA. Taken together, we have developed a highly efficient yeast transformation method that enables the generation of very large and productive human antibody libraries for antibody discovery, and we are now routinely making 10(9) libraries in a day for antibody engineering purposes.

  11. Infección oculta por el virus de la hepatitis B en hijos de madres positivas al HBsAg

    Directory of Open Access Journals (Sweden)

    Marité Bello-Corredor

    2016-04-01

    Full Text Available La infección oculta por el virus de la hepatitis B (IOB, se caracteriza por la presencia en suero o plasma del genoma viral (ADN-VHB y anticuerpos contra la proteína de la cápside (anti-HBc en ausencia del antígeno de superficie (HBsAg, marcador que tradicionalmente se emplea para identificar la presencia del virus. Con el objetivo de caracterizar la presencia de IOB en hijos de madres positivas al HBsAg, se estudiaron 291 muestras séricas de niños con la condición de ser HBsAg (- y anticuerpos anti-HBsAg (anti-HBs menores de 50 UI/L, conservadas en la seroteca del Laboratorio de Referencia Nacional de Hepatitis Virales. Se realizaron ensayos para determinar la exposición al virus (anti-HBc, a los sueros anti-HBc (+ se les realizó Reacción en Cadena de la Polimerasa en Tiempo Real (RCP-TR para determinar y cuantificar el ADN-VHB. La prevalencia de exposición al VHB (anti-HBc fue 16,8% (49/291. El ADN viral se cuantificó en el 14% (6/43 de los casos anti-HBc (+, observándose cargas virales que oscilaban entre 2,15 x 101 hasta 3,42 x 101 UI/mL. La prevalencia de la IOB para el total de los pacientes analizados fue 2,1% (6/291, considerada relativamente baja. No se encontró asociación significativa entre las variables sociodemográficas analizadas tales como: edad, sexo y provincia de procedencia. La IOB está presente en hijos de madres positivas al HBsAg, a pesar de la profilaxis contra la hepatitis B. Por lo tanto, se requiere de pesquisajes adecuados para detectar dicha entidad. Las implicaciones clínicas y epidemiológicas de la misma, requieren de un estrecho monitoreo y atención de estos pacientes. Este estudio se realiza por primera vez en Cuba y aporta conocimientos útiles para el diagnóstico, prevención y control de esta enfermedad en niños.

  12. Humoral and cellular immune responses to modified hepatitis B ...

    African Journals Online (AJOL)

    Purpose: To evaluate the immunogenicity and types of immune response of a quality-controlled modified recombinant hepatitis B surface antigen (HBsAg) plasmid encoding HBsAg in mice. Methods: The characterized plasmid DNA was used in the immunization of Balb/c mice. Three groups of mice were intramuscularly ...

  13. Frequency of hepatitis B surface antigen and anti-hepatitis c antibodies in apparently healthy blood donors in northern areas

    International Nuclear Information System (INIS)

    Alam, M.; Naeem, M.A.

    2007-01-01

    To determine the frequency of HBsAg and anti HCV among the potential blood donors belonging to Northern areas.A total of 8949 apparently healthy blood donors, belonging to Northern areas were screened for HBsAg and anti-HCV by rapid method.Overall sero-positivity of HBsAg was 3.66% and anti-HCV 1.35%. The result indicates that frequency of HBsAg is more than anti-HCV in Northern areas. (author)

  14. Type B Hepatitis in Iran

    Directory of Open Access Journals (Sweden)

    M. Tabarestani

    1977-01-01

    Full Text Available Hepatitis B surface antigen CHBsAg was found in 1% of controls, 2.1% of professional blood donors, 2.0% of leprosy patients and 76.1% of acute hepatitis in Tehran and Mashhad, Iran. All HBsAg positive samples also possessed antibody to the hepatitis B core antigen and all were subtype ayw. Type B hepatitis and the HBsAg state aloe frequent in Iran, but most must be accounted for by u nonparenter- al" or "rnapparent'' parenteral exposure.

  15. Cadmium, ATPase-P, yeast. From transport to toxicity

    International Nuclear Information System (INIS)

    Gardarin, Aurelie

    2007-01-01

    Two projects has been developed during my PhD. One consisting in the functional study of CadA, the Cd 2+ -ATPase from Listeria monocytogenes, the other one was focused on the toxicity of cadmium and the associated response of the yeast Saccharomyces cerevisiae. This two studies used a a phenotype of sensitivity to cadmium induced by CadA expression in yeast. This phenotype was used as a screening tool to identify essential amino acids of Cd transport by CadA and to study cadmium toxicity and the corresponding yeast cellular response. CadA actively transports Cd using ATP hydrolysis as energy source. Directed mutagenesis of the membranous polar, sulphur and charged amino-acids revealed that Cd transport pathway implied four transmembrane segments (Tm) and more precisely the cysteine C 354 , C 356 and proline P 355 of the CPC motif located in Tm6, aspartate D 692 in Tm8, glutamate E 164 in Tm4 and methionine M 149 in Tm5. From our studies, 2 Cd ions would be translocated for each hydrolysis ATP. Expression of CadA in the yeast Saccharomyces cerevisiae induces an hypersensitivity to Cd. A wild type cell can grow up to 100 μm cadmium whereas CadA expressing yeast cannot grow with 1 μm cadmium in the culture medium. This cadmium sensitivity was due to the localisation of CadA in the endoplasmic reticulum membrane. Transport of cadmium in this compartment produces an accumulation of mis-folded proteins that induces the Unfolded Protein Response (UPR). As UPR also occurs in a wild type yeast exposed to low Cd concentration, one can point out endoplasmic reticulum as a extremely sensitive cellular compartment. UPR also appears as an early response to Cd as it happens far before any visible signs of toxicity. (author) [fr

  16. Antigen-specific immature dendritic cell vaccine ameliorates anti-dsDNA antibody-induced renal damage in a mouse model.

    Science.gov (United States)

    Xia, Yumin; Jiang, Shan; Weng, Shenhong; Lv, Xiaochun; Cheng, Hong; Fang, Chunhong

    2011-12-01

    Dendritic cells (DCs) can inhibit immune response by clonal anergy when immature. Recent studies have shown that immature DCs (iDCs) may serve as a live cell vaccine after specific antigen pulse based on its potential of blocking antibody production. In this study, we aimed to investigate the effects of nuclear antigen-pulsed iDCs in the treatment of lupus-like renal damages induced by anti-dsDNA antibodies. iDCs were generated from haemopoietic stem cells in bone marrow and then pulsed in vitro with nuclear antigen. The iDC vaccine and corresponding controls were injected into mice with lupus-like renal damages. The evaluation of disease was monitored by biochemical parameters and histological scores. Anti-dsDNA antibody isotypes and T-lymphocyte-produced cytokines were analysed for elucidating therapeutic mechanisms. RESULTS; The mice treated with antigen-pulsed iDCs had a sustained remission of renal damage compared with those injected with non-pulsed iDCs or other controls, including decreased anti-dsDNA antibody level, less proteinuria, lower blood urea nitrogen and serum creatinine values, and improved histological evaluation. Analysis on isotypes of anti-dsDNA antibody showed that iDC vaccine preferentially inhibited the production of IgG3, IgG2b and IgG2a. Furthermore, administration of antigen-treated iDCs to mice resulted in significantly reduced IL-2, IL-4 and IL-12 and IFN-γ produced by T-memory cells. Conversely, the vaccination of antigen-pulsed mature DCs led to increased anti-dsDNA antibody production and an aggravation of lupus-like disease in the model. CONCLUSIONS; These results suggested the high potency of iDC vaccine in preventing lupus-like renal injuries induced by pathogenic autoantibodies.

  17. Invariant NKT cells are required for airway inflammation induced by environmental antigens

    OpenAIRE

    Wingender, Gerhard; Rogers, Paul; Batzer, Glenda; Lee, Myung Steve; Bai, Dong; Pei, Bo; Khurana, Archana; Kronenberg, Mitchell; Horner, Anthony A.

    2011-01-01

    Invariant NKT cells (iNKT cells) are a unique subset of T lymphocytes that rapidly carry out effector functions. In this study, we report that a majority of sterile house dust extracts (HDEs) tested contained antigens capable of activating mouse and human iNKT cells. HDEs had adjuvant-like properties in an ovalbumin (OVA)-induced asthma model, which were dependent on V?14i NKT cells, as vaccinated animals deficient for iNKT cells displayed significantly attenuated immune responses and airway ...

  18. 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.

  19. 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...

  20. Increased projection of MHC and tumor antigens in murine B16-BL6 melanoma induced by hydrostatic pressure and chemical crosslinking.

    Science.gov (United States)

    Ramakrishna, V; Eisenthal, A; Skornick, Y; Shinitzky, M

    1993-05-01

    The B16-BL6 melanoma, like most spontaneously arising tumors, is poorly immunogenic and expresses low levels of major histocompatibility complex (MHC) antigens. Treatment of cells of this tumor in vitro by hydrostatic pressure in the presence of adenosine 2',3'-dialdehyde (oxAdo), a membrane-impermeant crosslinker, caused elevated projection of MHC and a specific tumor antigen as demonstrated by flow-cytometric analysis. Maximum projection of both the MHC and the tumor antigens could be reached by application of 1200 atm for 15 min in the presence of 20 mM oxAdo. It is not yet clear whether this passive increase in availability of antigens on the cell surface originated from a dormant pool of antigens in the plasma membrane or from pressure-induced fusion of antigen-rich intracellular organelles (e.g. the endoplasmic reticulum). The immunogenic properties of the antigen-enriched B16-BL6 cells are described in the following paper.

  1. Diversity and origin of hepatitis B virus in Dutch blood donors

    NARCIS (Netherlands)

    Koppelman, M. H. G. M.; Zaaijer, H. L.

    2004-01-01

    Two considerations led us to study the genetic diversity and origin of hepatitis B virus (HBV) in Dutch blood donors. Firstly, an HBV-infected Dutch blood donor was found negative by four assays used commonly for detection of HBV surface antigen (HBsAg). How variable is HBsAg among HBV infected

  2. Chronological aging-induced apoptosis in yeast

    OpenAIRE

    Fabrizio, Paola; Longo, Valter D.

    2008-01-01

    Saccharomyces cerevisiae is the simplest among the major eukaryotic model organisms for aging and diseases. Longevity in the chronological life span paradigm is measured as the mean and maximum survival period of populations of non-dividing yeast. This paradigm has been used successfully to identify several life-regulatory genes and three evolutionary conserved pro-aging pathways. More recently, Schizosaccharomyces pombe has been shown to age chronologically in a manner that resembles that of...

  3. Correlation between HBsAg, prothrombin time activity, and indocyanine green retention rate at 15 minutes in patients with HBeAg-positive chronic HBV infection

    Directory of Open Access Journals (Sweden)

    FAN Wenhai

    2016-11-01

    Full Text Available ObjectiveTo investigate the correlation between HBsAg, prothrombin time activity (PTA, and indocyanine green retention rate at 15 minutes (ICG R15 in patients with HBeAg-positive chronic HBV infection. MethodsA total of 92 patients with HBeAg-positive chronic HBV infection who were admitted to The First Hospital of Lanzhou University from December 2015 to April 2016 were enrolled and divided into chronic hepatitis B (CHB group (24 patients, compensated liver cirrhosis group (38 patients, and decompensated liver cirrhosis group (30 patients. Serum HBsAg quantitation, PTA test, and liver reserve function test (ICG R15 were performed for all patients. The chi-square test was used for comparison of categorical data between groups, an analysis of variance was used for comparison of continuous data between multiple groups, and a Pearson correlation analysis was also performed. ResultsThere were significant differences between the three groups in serum HBsAg quantitation (3.82±0.43 log10IU/ml vs 2.88±0.36 log10IU/ml vs 2.60±0.27 log10IU/ml, F=25.19, P<0.001, ICG R15 (7.51%±3.10% vs 9.57%±8.18% vs 24.13%±14.28%, F=24.00, P=0.001, and PTA (8100%±1762% vs 83.08%±9.64% vs 62.32%±16.90%, F=13.42, P=0.009. The correlation analysis showed that PTA was negatively correlated with ICG R15 in all three groups (r=-0.948, -0.602, and -0.735, all P<0.01. In the compensated liver cirrhosis group and decompensated liver cirrhosis group, HBsAg was positively correlated with PTA (r=0.410 and 0.473, both P<0.05 and negatively correlated with ICG R15 (r=-0.427 and -0.768, P<0.01. ConclusionIn HBeAg positive patients, there are certain correlations between HBsAg, PTA, and ICG R15, which, to a certain degree, reflects the liver reserve function in patients with chronic HBV infection.

  4. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jufang, E-mail: jufangwang@impcas.ac.c [Institute of Modern Physics, Chinese Academy of Sciences, Nanchang Road No. 509, Lanzhou 730000 (China); Lu Dong; Wu Xin; Sun Haining; Ma Shuang; Li Renmin; Li Wenjian [Institute of Modern Physics, Chinese Academy of Sciences, Nanchang Road No. 509, Lanzhou 730000 (China)

    2010-09-15

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV {mu}m{sup -1}) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV {mu}m{sup -1}. The mutation cross section saturated when LET was higher than 58.2 keV {mu}m{sup -1}. Meanwhile, the highest RBE{sub i} for inactivation located at 120.0 keV {mu}m{sup -1} and the highest RBE{sub m} for mutation was at 58.2 keV {mu}m{sup -1}. The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  5. Dose-response association between hepatitis B surface antigen levels and liver cancer risk in Chinese men and women.

    Science.gov (United States)

    Yang, Yang; Gao, Jing; Li, Hong-Lan; Zheng, Wei; Yang, Gong; Zhang, Wei; Ma, Xiao; Tan, Yu-Ting; Rothman, Nathaniel; Gao, Yu-Tang; Chow, Wong-Ho; Shu, Xiao-Ou; Xiang, Yong-Bing

    2016-07-15

    We aimed at evaluating the risk of liver cancer in different levels of HBsAg among Chinese men and women. We carried out a nested case-control study including 363 cases and 3,511 controls in two population-based cohorts in Shanghai. Plasma samples collected at enrollment were quantified for HBsAg levels using the Architect QT assay. Conditional logistic regression was performed to estimate the odds ratios (ORs) and 95% confidence intervals (95% CIs) for liver cancer, with adjustment for potential confounders. HBsAg was detected in 6.29% of control subjects overall (7.02% in men and 4.98% in women). HBsAg levels were positively associated with liver cancer risk in a dose-response manner (ptrend  women. In men, the adjusted ORs increased from 7.27 (95% CI: 3.49-15.15) at the lowest detectable level of HBsAg (5-9 IU/ml) to 7.16 (95% CI: 3.21-15.96), 34.30 (95% CI: 16.94-69.44), and 47.33 (95% CI: 23.50-95.34) at the highest level of HBsAg (≥1,000 IU/ml) compared to those negative for HBsAg. The corresponding ORs were much lower for women, from 1.37 (95% CI: 0.25-7.47), 3.81 (95% CI: 1.09-13.28), 7.36 (95% CI: 2.41-22.46) and 16.86 (95% CI: 7.24-39.27), respectively. HBsAg quantification has potential to distinguish individuals at different risks of liver cancer. Men with the lowest detectable level of HBsAg should still pay attention to their liver cancer risks, but those with a higher level may be given a higher priority in future liver cancer surveillance program. © 2016 UICC.

  6. The role of the yeast as probiotic in protection against liver injury ...

    African Journals Online (AJOL)

    Saccharomyces cerevisiae is a well known yeast used safely from ancient times in many biotechnological applications. Nowadays, there is an increasing interest in using yeast as probiotic. Dimethyl nitrosamine (DMN) has been used to induce liver fibrosis in rats. Yeast has been used side by side with the DMN to evaluate ...

  7. 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

  8. 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 .

  9. Yeast signaling pathways in the oxidative stress response

    Energy Technology Data Exchange (ETDEWEB)

    Ikner, Aminah [Section of Microbiology, Division of Biological Sciences, University of California, Davis, CA 95616 (United States); Shiozaki, Kazuhiro [Section of Microbiology, Division of Biological Sciences, University of California, Davis, CA 95616 (United States)]. E-mail: kshiozaki@ucdavis.edu

    2005-01-06

    Oxidative stress that generates the reactive oxygen species (ROS) is one of the major causes of DNA damage and mutations. The 'DNA damage checkpoint' that arrests cell cycle and repairs damaged DNA has been a focus of recent studies, and the genetically amenable model systems provided by yeasts have been playing a leading role in the eukaryotic checkpoint research. However, means to eliminate ROS are likely to be as important as the DNA repair mechanisms in order to suppress mutations in the chromosomal DNA, and yeasts also serve as excellent models to understand how eukaryotes combat oxidative stress. In this article, we present an overview of the signaling pathways that sense oxidative stress and induce expression of various anti-oxidant genes in the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe and the pathogenic yeast Candida albicans. Three conserved signaling modules have been identified in the oxidative stress response of these diverse yeast species: the stress-responsive MAP kinase cascade, the multistep phosphorelay and the AP-1-like transcription factor. The structure and function of these signaling modules are discussed.

  10. Yeast signaling pathways in the oxidative stress response

    International Nuclear Information System (INIS)

    Ikner, Aminah; Shiozaki, Kazuhiro

    2005-01-01

    Oxidative stress that generates the reactive oxygen species (ROS) is one of the major causes of DNA damage and mutations. The 'DNA damage checkpoint' that arrests cell cycle and repairs damaged DNA has been a focus of recent studies, and the genetically amenable model systems provided by yeasts have been playing a leading role in the eukaryotic checkpoint research. However, means to eliminate ROS are likely to be as important as the DNA repair mechanisms in order to suppress mutations in the chromosomal DNA, and yeasts also serve as excellent models to understand how eukaryotes combat oxidative stress. In this article, we present an overview of the signaling pathways that sense oxidative stress and induce expression of various anti-oxidant genes in the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe and the pathogenic yeast Candida albicans. Three conserved signaling modules have been identified in the oxidative stress response of these diverse yeast species: the stress-responsive MAP kinase cascade, the multistep phosphorelay and the AP-1-like transcription factor. The structure and function of these signaling modules are discussed

  11. Yeast surface display platform for rapid discovery of conformationally selective nanobodies

    DEFF Research Database (Denmark)

    McMahon, Conor; Baier, Alexander S.; Pascolutti, Roberta

    2018-01-01

    this problem, we report a fully in vitro platform for nanobody discovery based on yeast surface display. We provide a blueprint for identifying nanobodies, demonstrate the utility of the library by crystallizing a nanobody with its antigen, and most importantly, we utilize the platform to discover...... conformationally selective nanobodies to two distinct human GPCRs. To facilitate broad deployment of this platform, the library and associated protocols are freely available for nonprofit research....

  12. Performance of hepatitis B assays on the Bayer ADVIA Centaur Immunoassay System.

    Science.gov (United States)

    van Helden, Josef; Denoyel, Gérard; Karwowska, Sylwia; Reamer, Randy; Schmalz, John; Wright, Ted; Preisel-Simmons, Barbara

    2004-01-01

    Bayer HealthCare LLC, Diagnostics Division, has developed several new assays on the ADVIA Centaur immunoassay system for the detection of markers of hepatitis B virus infection in human serum and plasma. This panel includes assays for: hepatitis B surface antigen (HBsAg), a confirmatory test method for HBsAg, antibodies to hepatitis B surface antigen (anti-HBs), IgM and IgG antibodies to hepatitis B core antigen (anti-HBc Total) and IgM antibodies to hepatitis B core antigen (anti-HBc IgM). These assays employ magnetic particle separation technology with direct chemiluminescence for optimal assay performance. All of the assays are fully automated, require sample volumes ranging from 15 microl to 100 microl (with the exception of the ADVIA Centaur HBsAg Confirmatory Assay, which requires 2 x 100 microl), and have throughputs of up to 240 tests per hour. The five ADVIA Centaur HBV assays were tested in extensive performance evaluations conducted at two sites in Europe. The performance evaluations, which included samples from HBV-infected individuals, blood donors, hospitalized/clinical patients, and HBV vaccinees (for Anti-HBs evaluation), generated performance data in support of obtaining the Communautés Européennes (CE) mark for European market distribution. The HBV performance evaluations resulted in an overall diagnostic specificity > 99%, i.e. 99.94% for the ADVIA Centaur HBsAg Assay, 100% for the ADVIA Centaur Anti-HBs Assay, 100% for the ADVIA Centaur HBc IgM Assay and 99.94% for the ADVIA Centaur HBc Total Assay. All of the ADVIA Centaur assays showed a very good diagnostic sensitivity on these populations with 100% for the ADVIA Centaur HBsAg Assay, 99.0% for the ADVIA Centaur Anti-HBs Assay, 98.53% for the ADVIA Centaur HBc IgM Assay and 100% for the ADVIA Centaur HBc Total Assay. The ADVIA Centaur HBsAg Confirmatory Test confirmed 100% of the positive HBsAg samples. Testing of interfering substances and potential cross-reacting samples for all ADVIA

  13. Semi-allogeneic dendritic cells can induce antigen-specific T-cell activation, which is not enhanced by concurrent alloreactivity.

    Science.gov (United States)

    Wells, James W; Cowled, Chris J; Darling, David; Guinn, Barbara-Ann; Farzaneh, Farzin; Noble, Alistair; Galea-Lauri, Joanna

    2007-12-01

    Alloreactive T-cell responses are known to result in the production of large amounts of proinflammatory cytokines capable of activating and maturing dendritic cells (DC). However, it is unclear whether these allogeneic responses could also act as an adjuvant for concurrent antigen-specific responses. To examine effects of simultaneous alloreactive and antigen-specific T-cell responses induced by semi-allogeneic DC. Semi-allogeneic DC were generated from the F(1) progeny of inbred strains of mice (C57BL/6 and C3H, or C57BL/6 and DBA). We directly primed antigen-specific CD8(+) and CD4(+) T-cells from OT-I and OT-II mice, respectively, in the absence of allogeneic responses, in vitro, and in the presence or absence of alloreactivity in vivo. In vitro, semi-allogeneic DC cross-presented ovalbumin (OVA) to naïve CD8(+) OT-I transgenic T-cells, primed naïve CD4(+) OT-II transgenic T-cells and could stimulate strong alloreactive T-cell proliferation in a primary mixed lymphocyte reaction (MLR). In vivo, semi-allogeneic DC migrated efficiently to regional lymph nodes but did not survive there as long as autologous DC. In addition, they were not able to induce cytotoxic T-lymphocyte (CTL) activity to a target peptide, and only weakly stimulated adoptively transferred OT-II cells. The CD4(+) response was unchanged in allo-tolerized mice, indicating that alloreactive T-cell responses could not provide help for concurrently activated antigen-specific responses. In an EL4 tumour-treatment model, vaccination with semi-allogeneic DC/EL4 fusion hybrids, but not allogeneic DC/EL4 hybrids, significantly increased mouse survival. Expression of self-Major histocompatibility complex (MHC) by semi-allogeneic DC can cause the induction of antigen-specific immunity, however, concurrently activated allogeneic bystander responses do not provide helper or adjuvant effects.

  14. Development of hen antihepatitis B antigen IgY-based conjugate for ELISA assay

    Directory of Open Access Journals (Sweden)

    Najat Muayed Nafea

    2015-01-01

    Conclusions: This study showed that laying hens can be used as an alternative source for production of polyclonal antibodies against HBsAg and anti-HBs IgY could be labeled with HRP enzyme and could subsequently be used successfully as secondary antibody in ELISA for detection of HBsAg in the patients sera.

  15. Caloric Restriction-Induced Extension of Chronological Lifespan Requires Intact Respiration in Budding Yeast.

    Science.gov (United States)

    Kwon, Young-Yon; Lee, Sung-Keun; Lee, Cheol-Koo

    2017-04-01

    Caloric restriction (CR) has been shown to extend lifespan and prevent cellular senescence in various species ranging from yeast to humans. Many effects of CR may contribute to extend lifespan. Specifically, CR prevents oxidative damage from reactive oxygen species (ROS) by enhancing mitochondrial function. In this study, we characterized 33 single electron transport chain (ETC) gene-deletion strains to identify CR-induced chronological lifespan (CLS) extension mechanisms. Interestingly, defects in 17 of these 33 ETC gene-deleted strains showed loss of both respiratory function and CR-induced CLS extension. On the contrary, the other 16 respiration-capable mutants showed increased CLS upon CR along with increased mitochondrial membrane potential (MMP) and intracellular adenosine triphosphate (ATP) levels, with decreased mitochondrial superoxide generation. We measured the same parameters in the 17 non-respiratory mutants upon CR. CR simultaneously increased MMP and mitochondrial superoxide generation without altering intracellular ATP levels. In conclusion, respiration is essential for CLS extension by CR and is important for balancing MMP, ROS, and ATP levels.

  16. Improving industrial yeast strains: exploiting natural and artificial diversity

    Science.gov (United States)

    Steensels, Jan; Snoek, Tim; Meersman, Esther; Nicolino, Martina Picca; Voordeckers, Karin; Verstrepen, Kevin J

    2014-01-01

    Yeasts have been used for thousands of years to make fermented foods and beverages, such as beer, wine, sake, and bread. However, the choice for a particular yeast strain or species for a specific industrial application is often based on historical, rather than scientific grounds. Moreover, new biotechnological yeast applications, such as the production of second-generation biofuels, confront yeast with environments and challenges that differ from those encountered in traditional food fermentations. Together, this implies that there are interesting opportunities to isolate or generate yeast variants that perform better than the currently used strains. Here, we discuss the different strategies of strain selection and improvement available for both conventional and nonconventional yeasts. Exploiting the existing natural diversity and using techniques such as mutagenesis, protoplast fusion, breeding, genome shuffling and directed evolution to generate artificial diversity, or the use of genetic modification strategies to alter traits in a more targeted way, have led to the selection of superior industrial yeasts. Furthermore, recent technological advances allowed the development of high-throughput techniques, such as ‘global transcription machinery engineering’ (gTME), to induce genetic variation, providing a new source of yeast genetic diversity. PMID:24724938

  17. Detection and quantitative determination by PIXE of the mutagen Sn2+ in yeast cells

    International Nuclear Information System (INIS)

    Viau, C.M.; Yoneama, M.-L.; Dias, J.F.; Pungartnik, C.; Brendel, M.; Henriques, J.A.P.

    2006-01-01

    The main goal of this work was to determine the concentration of Sn 2+ ions in cells of the yeast Saccharomyces cerevisiae and to correlate their quantity with the genotoxicity of intracellularly accumulated metal ions. The intracellular metal content of yeast cells was determined by PIXE (particle-induced X-ray emission) after cell exposure to SnCl 2 . To that end, a thick target protocol was developed for PIXE analysis. The samples were irradiated with a 2 MeV proton beam, while the induced X-rays were detected with a high-purity germanium detector. The results of the toxicity of SnCl 2 and the PIXE analysis performed with two different yeast strains (haploid and diploid) suggest that the exposure of haploid and diploid yeast to Sn 2+ induces DNA lesions and that the absorption depends on the genetic background of each strain

  18. Interleukin 13– and interleukin 17A–induced pulmonary hypertension phenotype due to inhalation of antigen and fine particles from air pollution

    Science.gov (United States)

    Park, Sung-Hyun; Chen, Wen-Chi; Esmaeil, Nafiseh; Lucas, Benjamin; Marsh, Leigh M.; Reibman, Joan

    2014-01-01

    Abstract Pulmonary hypertension has a marked detrimental effect on quality of life and life expectancy. In a mouse model of antigen-induced pulmonary arterial remodeling, we have recently shown that coexposure to urban ambient particulate matter (PM) significantly increased the thickening of the pulmonary arteries and also resulted in significantly increased right ventricular systolic pressures. Here we interrogate the mechanism and show that combined neutralization of interleukin 13 (IL-13) and IL-17A significantly ameliorated the increase in right ventricular systolic pressure, the circumferential muscularization of pulmonary arteries, and the molecular change in the right ventricle. Surprisingly, our data revealed a protective role of IL-17A for the antigen- and PM-induced severe thickening of pulmonary arteries. This protection was due to the inhibition of the effects of IL-13, which drove this response, and the expression of metalloelastase and resistin-like molecule α. However, the latter was redundant for the arterial thickening response. Anti-IL-13 exacerbated airway neutrophilia, which was due to a resulting excess effect of IL-17A, confirming concurrent cross inhibition of IL-13- and IL-17A-dependent responses in the lungs of animals exposed to antigen and PM. Our experiments also identified IL-13/IL-17A-independent molecular reprogramming in the lungs induced by exposure to antigen and PM, which indicates a risk for arterial remodeling and protection from arterial constriction. Our study points to IL-13- and IL-17A-coinduced inflammation as a new template for biomarkers and therapeutic targeting for the management of immune response–induced pulmonary hypertension. PMID:25610601

  19. Attenuation of yeast form of Paracoccidioides Brasiliensis by gamma irradiation; Atenuacao da forma leveduriforme do Paraccocidioides Brasiliensis por irradicao gama

    Energy Technology Data Exchange (ETDEWEB)

    Demicheli, Marina Cortez

    2006-07-01

    Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent mycosis in Latin America, and currently there is no effective vaccine. The aim of this work was to attenuate the yeast form of P. brasiliensis by gamma irradiation for further studies on vaccine research. P. brasiliensis (strain Pb-18) cultures were irradiated at doses between 0.5 and 8.0 kGy. After each dose the fungal cells were plated and after 10 days the colony forming units (CFU) counted. The viability of the irradiated cells was measured using the dyes Janus green and methylene blue, and protein synthesis by incorporation of L {sup 35}S methionine. The comparison between the antigenic profile of irradiated and control yeast was made by Western blot and the virulence evaluated by the inoculation in C{sub 57}Bl/J6 and Balb/c mice. Morphological changes in irradiated yeast were evaluated by electronic microscopy and DNA integrity by electrophoresis in agarose gel. At 6.5 kGy the yeast lost the reproductive capacity. The viability and the incorporation of L- {sup 35}S methionine were the same in control and up to 6.5 kGy irradiated cells, but 6.5 kGy irradiated yeast secreted 40% less proteins. The Western blot profile was clearly similar in control and 6.5 kGy irradiated yeast. No CFU could be recovered from the tissues of the mice infected with the radio attenuated yeast. At the dose of 6.5 kGy the DNA was degraded and this damage was not repaired. The transmission electronic microscopy showed significant alterations in the nucleus of the irradiated cells. The scanning electronic microscopy showed that two hours after the irradiation the cells were collapsed or presented deep folds in the surface, however these injury were reversible. We concluded that for P. brasiliensis yeast cells it was possible to find a dose in which the pathogen loses its reproductive ability and virulence, while retaining its viability, metabolic activity and the antigenic profile. (author)

  20. Antibody-antigen-adjuvant conjugates enable co-delivery of antigen and adjuvant to dendritic cells in cis but only have partial targeting specificity.

    Directory of Open Access Journals (Sweden)

    Martin Kreutz

    Full Text Available Antibody-antigen conjugates, which promote antigen-presentation by dendritic cells (DC by means of targeted delivery of antigen to particular DC subsets, represent a powerful vaccination approach. To ensure immunity rather than tolerance induction the co-administration of a suitable adjuvant is paramount. However, co-administration of unlinked adjuvant cannot ensure that all cells targeted by the antibody conjugates are appropriately activated. Furthermore, antigen-presenting cells (APC that do not present the desired antigen are equally strongly activated and could prime undesired responses against self-antigens. We, therefore, were interested in exploring targeted co-delivery of antigen and adjuvant in cis in form of antibody-antigen-adjuvant conjugates for the induction of anti-tumour immunity. In this study, we report on the assembly and characterization of conjugates consisting of DEC205-specific antibody, the model antigen ovalbumin (OVA and CpG oligodeoxynucleotides (ODN. We show that such conjugates are more potent at inducing cytotoxic T lymphocyte (CTL responses than control conjugates mixed with soluble CpG. However, our study also reveals that the nucleic acid moiety of such antibody-antigen-adjuvant conjugates alters their binding and uptake and allows delivery of the antigen and the adjuvant to cells partially independently of DEC205. Nevertheless, antibody-antigen-adjuvant conjugates are superior to antibody-free antigen-adjuvant conjugates in priming CTL responses and efficiently induce anti-tumour immunity in the murine B16 pseudo-metastasis model. A better understanding of the role of the antibody moiety is required to inform future conjugate vaccination strategies for efficient induction of anti-tumour responses.

  1. yeast transformation of Mucor circinelloides Tieghe

    African Journals Online (AJOL)

    GRACE

    2006-05-02

    May 2, 2006 ... A nested model analysis of variance of growth data of induced yeast .... Figure 2. Mean biomass and relative growth rates of M. circinelloides cultivated in treatments in ..... Pullman B (ed) Frontiers in Physicochemical Biology.

  2. Alphavirus Replicon DNA Vectors Expressing Ebola GP and VP40 Antigens Induce Humoral and Cellular Immune Responses in Mice

    Directory of Open Access Journals (Sweden)

    Shoufeng Ren

    2018-01-01

    Full Text Available Ebola virus (EBOV causes severe hemorrhagic fevers in humans, and no approved therapeutics or vaccine is currently available. Glycoprotein (GP is the major protective antigen of EBOV, and can generate virus-like particles (VLPs by co-expression with matrix protein (VP40. In this study, we constructed a recombinant Alphavirus Semliki Forest virus (SFV replicon vector DREP to express EBOV GP and matrix viral protein (VP40. EBOV VLPs were successfully generated and achieved budding from 293 cells after co-transfection with DREP-based GP and VP40 vectors (DREP-GP+DREP-VP40. Vaccination of BALB/c mice with DREP-GP, DREP-VP40, or DREP-GP+DREP-VP40 vectors, followed by immediate electroporation resulted in a mixed IgG subclass production, which recognized EBOV GP and/or VP40 proteins. This vaccination regimen also led to the generation of both Th1 and Th2 cellular immune responses in mice. Notably, vaccination with DREP-GP and DREP-VP40, which produces both GP and VP40 antigens, induced a significantly higher level of anti-GP IgG2a antibody and increased IFN-γ secreting CD8+ T-cell responses relative to vaccination with DREP-GP or DREP-VP40 vector alone. Our study indicates that co-expression of GP and VP40 antigens based on the SFV replicon vector generates EBOV VLPs in vitro, and vaccination with recombinant DREP vectors containing GP and VP40 antigens induces Ebola antigen-specific humoral and cellular immune responses in mice. This novel approach provides a simple and efficient vaccine platform for Ebola disease prevention.

  3. Plasmodium berghei: immunosuppression of the cell-mediated immune response induced by nonviable antigenic preparations

    International Nuclear Information System (INIS)

    Gross, A.; Frankenburg, S.

    1989-01-01

    In this work, plasmodial antigens were examined for their ability to suppress the cellular immune response during lethal Plasmodium berghei infection. Splenic enlargement and the number and function of white spleen cells were assessed after injection of normal mice with irradiated parasitized erythrocytes (IPE) or with parasitized erythrocytes (PE) membranes. Both IPE and PE membranes caused splenomegaly and an increase in the number of splenic white cells with concurrent alteration of the relative proportions of T cells and macrophages. The percentage of T lymphocytes was fractionally diminished, but there was a marked increase in Lyt 2.2 positive (suppressor and cytotoxic) T subsets and in the number of splenic macrophage precursors. The pathological enlargement of the spleen was induced by various plasma membrane-derived antigens containing both proteins and carbohydrates. Splenocytes of mice injected with liposomes containing deoxycholate-treated PE or PE fractions showed both diminished interleukin 2 production and a decreased response to mitogen. It appears that some of the changes in the cellular immune response during P. berghei infection are a consequence of the massive provision of a wide spectrum of antigens, capable of suppressing the immune response. Thus, it may be appropriate to evaluate the possible negative effect of parasite epitopes that are candidates for vaccine

  4. Commercial bacterins did not induce detectable levels of antibodies in mice against Mycoplasma hyopneumoniae antigens strongly recognized by swine immune system

    Directory of Open Access Journals (Sweden)

    Andressa Fisch

    2016-01-01

    Full Text Available Enzootic Pneumonia (EP caused by Mycoplasma hyopneumoniae results in major economic losses to the swine industry. Hence, the identification of factors that provide protection against EP could help to develop effective vaccines. One such factor that provides partial protection are bacterins. Therefore, the aim of this study was to verify the induction of antibodies against fifteen M. hyopneumoniae antigens, strongly recognized by the swine immune system during natural infection, in mice vaccinated with six commercial bacterins. Each group of mice was inoculated with one bacterin, and seroconversion was assessed by indirect ELISA using recombinant antigens and M. hyopneumoniae 7448 whole cell extract. Sera from one inoculated group recognized antigen MHP_0067, and sera from four inoculated groups recognized antigens MHP_0513 and MHP_0580. None of the bacterins was able to induce seroconversion against the twelve remaining antigens. This absence of a serological response could be attributed to the lack of antigen expression in M. hyopneumoniae strains used in bacterin production. Additionally the partial protection provided by these vaccines could be due to low expression or misfolding of antigens during vaccine preparation. Therefore, the supplementation of bacterins with these recombinant antigens could be a potential alternative in the development of more effective vaccines.

  5. Break-induced ATR and Ddb1-Cul4(Cdt)² ubiquitin ligase-dependent nucleotide synthesis promotes homologous recombination repair in fission yeast

    DEFF Research Database (Denmark)

    Moss, Jennifer; Tinline-Purvis, Helen; Walker, Carol A

    2010-01-01

    Nucleotide synthesis is a universal response to DNA damage, but how this response facilitates DNA repair and cell survival is unclear. Here we establish a role for DNA damage-induced nucleotide synthesis in homologous recombination (HR) repair in fission yeast. Using a genetic screen, we found...... the Ddb1-Cul4(Cdt)² ubiquitin ligase complex and ribonucleotide reductase (RNR) to be required for HR repair of a DNA double-strand break (DSB). The Ddb1-Cul4(Cdt)² ubiquitin ligase complex is required for degradation of Spd1, an inhibitor of RNR in fission yeast. Accordingly, deleting spd1(+) suppressed...

  6. Screening of respiration deficiency mutants of yeasts (Saccharomyces cerevisiae) induced by ion irradiation and the mtDNA restriction analysis

    International Nuclear Information System (INIS)

    Mao Shuhong; Chinese Academy of Sciences, Beijing; Jin Genming; Wei Zengquan; Xie Hongmei; Ma Qiufeng; Gu Ying

    2005-01-01

    Screening of the respiration deficiency mutants of Saccharomyces cerevisiae induced by 5.19 MeV/u 22 Ne 5+ ion irradiation is reported in this paper. Some respiration deficiency mutants of white colony phenotype, in a condition of selective culture of TTC medium, were obtained. A new and simplified method based on mtDNA restriction analysis is described. The authors found that there are many obvious differences in mtDNAs between wild yeasts and the respiration deficiency mutants. The mechanism of obtaining the respiration deficiency mutants induced by heavy ion irradiation is briefly discussed. (authors)

  7. Accelerated heavy ions induced DNA double-strand breaks in yeast cells

    International Nuclear Information System (INIS)

    Akpa, T.C.

    1993-01-01

    Yeast cells of strain cerevisiae, were irradiated with monoenergetic heavy ions, X-rays and α particles and assayed for DNA double-strand breaks and cell survival. The method of neutral sucrose gradient velocity sedimentation was used for all heavy-ion experiments because it is a well established technique.The method of pulsed-field gel electrophoresis was used for X-rays, α particles and argon ions. Results show that within the range of LET of the particles used (300 - 10 5 KeV/μm) the induction cross-section for DNA double-strand break is constant between 300 and around 7000 KeV/μm and increases at higher LET values. The inactivation cross-section follow the same trend. The DSB-induction and inactivation cross-section was shown to be linearly related with a slope of (1.01±0.15)/109 gmol-i. The RBE for DSB -induced decreases with LET and tails off at high LET values also. These results when compared with results from literature shows that the trend of induction is first monotonic rise of rate of DSB-induction up to 100keV/μm, followed by a plateau and a further rise which is due to increased effect of energetic γ-rays formed as shown for survival studies and predicted is possible to separate the cell DNA contents into 13 to 15 chromosome bands. The relative decrease in DNA content of the first band as determined by ethidium bromide-UV fluorescence decreases exponentially. The cross-section for DSB-induction determined by this method are (9.8±0.01)dsb/10 12 gmol - 1 Gy - 1, for 80 kV X-rays in haploid 211 yeast strain; (0.04+0.003)dsb/109gmol - 1μm 2 for Am-radioisotope α particles in haploid cells, (0.184±0.034) dsb/10 9 gmol - 1μm 2 in diploid 211*B cells and (0.55±0.04) dsb/10 9 gmol - 1μm 2 for 7MeV Argon ion in the diploid cells. The values are comparable to those obtained with velocity sedimentation technique. However, the reason for the low value obtained for a particle induced DSB in haploid cells is not clear

  8. The Lumipulse G HBsAg-Quant assay for screening and quantification of the hepatitis B surface antigen.

    Science.gov (United States)

    Yang, Ruifeng; Song, Guangjun; Guan, Wenli; Wang, Qian; Liu, Yan; Wei, Lai

    2016-02-01

    Qualitative HBsAg assay is used to screen HBV infection for decades. The utility of quantitative assay is also rejuvenated recently. We aimed to evaluate and compare the performance of a novel ultra-sensitive and quantitative assay, the Lumipulse assay, with the Architect and Elecsys assays. As screening methods, specificity was compared using 2043 consecutive clinical routine samples. As quantitative assays, precision and accuracy were assessed. Sera from 112 treatment-naïve chronic hepatitis B patients, four patients undergoing antiviral therapy and one patient with acute infection were tested to compare the correlations. Samples with concurrent HBsAg/anti-HBs were also quantified. The Lumipulse assay precisely quantified ultra-low level of HBsAg (0.004 IU/mL). It identified additional 0.98% (20/2043) clinical samples with trance amount of HBsAg. Three assays displayed excellent linear correlations irrespective of genotypes and S-gene mutations (R(2)>0.95, PLumipulse assay did not yield higher HBsAg concentrations in samples with concomitant anti-HBs. Compared with other assays, the Lumipulse assay is sensitive and specific for detecting HBsAg. The interpretation of the extremely low-level results, however, is challenging. Quantitative HBsAg results by different assays are highly correlated, but they should be interpreted interchangeably only after conversion to eliminate the biases. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Differing results of direct and indirect solid phase radioimmunoassay for HBsAg in acute hepatitis

    International Nuclear Information System (INIS)

    Strohm, W.D.; Legler, K.; Gerlich, W.; Stamm, B.; Zimmer, S.; Biotest-Serum-Institut G.m.b.H., Frankfurt am Main; Goettingen Univ.

    1978-01-01

    In 54 patients suffering from active viral hepatitis the indirect solid phase radioimmunoassay (ind-SPRIA) for HBsAg was positive in 9 cases the direct solid phase radioimmunoassay (d-SPRIA) being negative. In 2 further cases ind-SPRIA was positive during several weeks but d-SPRIA only once. AntiHBc could be detected in 9 of these patients. In 7 patients the usual decrease of the transaminase activity was followed by a second elavation with prolongation of the disease. The unknown factor detected by ind-SPRIA suggests a special of acute hepatitis. (orig.) [de

  10. Differing results of direct and indirect solid phase radioimmunoassay for HBsAg in acute hepatitis

    Energy Technology Data Exchange (ETDEWEB)

    Strohm, W D; Legler, K; Gerlich, W; Stamm, B; Zimmer, S [Frankfurt Univ. (Germany, F.R.). Abt. fuer Gastroenterologie; Biotest-Serum-Institut G.m.b.H., Frankfurt am Main (Germany, F.R.); Goettingen Univ. (Germany, F.R.). Hygiene-Institut)

    1978-09-01

    In 54 patients suffering from active viral hepatitis the indirect solid phase radioimmunoassay (ind-SPRIA) for HBsAg was positive in 9 cases the direct solid phase radioimmunoassay (d-SPRIA) being negative. In 2 further cases ind-SPRIA was positive during several weeks but d-SPRIA only once. AntiHBc could be detected in 9 of these patients. In 7 patients the usual decrease of the transaminase activity was followed by a second elavation with prolongation of the disease. The unknown factor detected by ind-SPRIA suggests a special of acute hepatitis.

  11. 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 ...

  12. Detection of Avian Antigen-Specific T Cells Induced by Viral Vaccines

    DEFF Research Database (Denmark)

    Dalgaard, Tina Sørensen; Norup, Liselotte Rothmann; Juul-Madsen, Helle Risdahl

    2016-01-01

    Live attenuated viral vaccines are widely used in commercial poultry production, but the development of new effective inactivated/subunit vaccines is needed. Studies of avian antigen-specific T cells are primarily based on analyses ex vivo after activating the cells with recall antigen. There is ......Live attenuated viral vaccines are widely used in commercial poultry production, but the development of new effective inactivated/subunit vaccines is needed. Studies of avian antigen-specific T cells are primarily based on analyses ex vivo after activating the cells with recall antigen...

  13. Seroprevalence of hepatitis B virus infection among antenatal clinic ...

    African Journals Online (AJOL)

    Saharan Africa. The risk of vertical transmission increases if the mother is hepatitis B surface antigen (HBsAg) positive and more so when she is also hepatitis B envelope antigen (HBeAg) positive. Since 2000, the World Health Organization ...

  14. Mutations induced by X-radiation in the yeast Schizosaccharomyces pombe

    International Nuclear Information System (INIS)

    Loprieno, N.; Barale, R.; Baroncelli, S.; Cammellini, A.; Melani, M.; Nieri, R.; Nozzolini, M.; Rossi, A.M.; Pisa Univ.

    1975-01-01

    Experiments on strains of yeast with different genetic backgrounds were done to evaluate the kinetics of inactivation and mutation induction by X-radiation. A system of forward mutation induction in five loci was used and a specific mutation rate was evaluated for the wild type. From a comparison of observations with wild type and radiation-sensitive strains, it may be assumed that in this yeast, mutations are mainly the result of a repair-active process. The range of genotypic and phenotypic influence upon the specific locus mutation rate was evaluated with appropriate biological material and experiments

  15. Expression of salt-induced 2-Cys peroxiredoxin from Oryza sativa increases stress tolerance and fermentation capacity in genetically engineered yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Kim, Il-Sup; Kim, Young-Saeng; Yoon, Ho-Sung

    2013-04-01

    Peroxiredoxins (Prxs), also termed thioredoxin peroxidases (TPXs), are a family of thiol-specific antioxidant enzymes that are critically involved in cell defense and protect cells from oxidative damage. In this study, a putative chloroplastic 2-Cys thioredoxin peroxidase (OsTPX) was identified by proteome analysis from leaf tissue samples of rice (Oryza sativa) seedlings exposed to 0.1 M NaCl for 3 days. To investigate the relationship between the OsTPX gene and the stress response, OsTPX was cloned into the yeast expression vector p426GPD under the control of the glyceraldehyde-3-phosphate dehydrogenase (GPD1) promoter, and the construct was transformed into Saccharomyces cerevisiae cells. OsTPX expression was confirmed by semi-quantitative reverse transcription-polymerase chain reaction and western blot analyses. OsTPX contained two highly conserved cysteine residues (Cys114 and Cys236) and an active site region (FTFVCPT), and it is structurally very similar to human 2-Cys Prx. Heterologous OsTPX expression increased the ability of the transgenic yeast cells to adapt and recover from reactive oxygen species (ROS)-induced oxidative stresses, such as a reduction of cellular hydroperoxide levels in the presence of hydrogen peroxide and menadione, by improving redox homeostasis. OsTPX expression also conferred enhanced tolerance to tert-butylhydroperoxide, heat shock, and high ethanol concentrations. Furthermore, high OsTPX expression improved the fermentation capacity of the yeast during glucose-based batch fermentation at a high temperature (40 °C) and at the general cultivation temperature (30 °C). The alcohol yield in OsTPX-expressing transgenic yeast increased by approximately 29 % (0.14 g g(-1)) and 21 % (0.12 g g(-1)) during fermentation at 40 and 30 °C, respectively, compared to the wild-type yeast. Accordingly, OsTPX-expressing transgenic yeast showed prolonged cell survival during the environmental stresses produced during fermentation. These

  16. Effects of Saccharomyces cerevisiae or boulardii yeasts on acute stress induced intestinal dysmotility.

    Science.gov (United States)

    West, Christine; Stanisz, Andrew M; Wong, Annette; Kunze, Wolfgang A

    2016-12-28

    To investigate the capacity of Saccharomyces cerevisiae ( S. cerevisiae ) and Saccharomyces boulardii ( S. boulardii ) yeasts to reverse or to treat acute stress-related intestinal dysmotility. Adult Swiss Webster mice were stressed for 1 h in a wire-mesh restraint to induce symptoms of intestinal dysmotility and were subsequently killed by cervical dislocation. Jejunal and colon tissue were excised and placed within a tissue perfusion bath in which S. cerevisiae , S. boulardii , or their supernatants were administered into the lumen. Video recordings of contractility and gut diameter changes were converted to spatiotemporal maps and the velocity, frequency, and amplitude of propagating contractile clusters (PCC) were measured. Motility pre- and post-treatment was compared between stressed animals and unstressed controls. S. boulardii and S. cerevisiae helped to mediate the effects of stress on the small and large intestine. Restraint stress reduced jejunal transit velocity (mm/s) from 2.635 ± 0.316 to 1.644 ± 0.238, P boulardii helped to restore jejunal and colonic velocity towards the unstressed controls; 1.833 ± 0.688 to 2.627 ± 0.664, P boulardii or S. cerevisiae supernatants also helped to restore motility to unstressed values in similar capacity. There is a potential therapeutic role for S. cerevisiae and S. boulardii yeasts and their supernatants in the treatment of acute stress-related gut dysmotility.

  17. Improving industrial yeast strains: exploiting natural and artificial diversity.

    Science.gov (United States)

    Steensels, Jan; Snoek, Tim; Meersman, Esther; Picca Nicolino, Martina; Voordeckers, Karin; Verstrepen, Kevin J

    2014-09-01

    Yeasts have been used for thousands of years to make fermented foods and beverages, such as beer, wine, sake, and bread. However, the choice for a particular yeast strain or species for a specific industrial application is often based on historical, rather than scientific grounds. Moreover, new biotechnological yeast applications, such as the production of second-generation biofuels, confront yeast with environments and challenges that differ from those encountered in traditional food fermentations. Together, this implies that there are interesting opportunities to isolate or generate yeast variants that perform better than the currently used strains. Here, we discuss the different strategies of strain selection and improvement available for both conventional and nonconventional yeasts. Exploiting the existing natural diversity and using techniques such as mutagenesis, protoplast fusion, breeding, genome shuffling and directed evolution to generate artificial diversity, or the use of genetic modification strategies to alter traits in a more targeted way, have led to the selection of superior industrial yeasts. Furthermore, recent technological advances allowed the development of high-throughput techniques, such as 'global transcription machinery engineering' (gTME), to induce genetic variation, providing a new source of yeast genetic diversity. © 2014 The Authors. FEMS Microbiology Reviews published by John Wiley & Sons Ltd on behalf of Federation of European Microbiological Societies.

  18. Multiepitope fusion antigen induces broadly protective antibodies that prevent adherence of Escherichia coli strains expressing colonization factor antigen I (CFA/I), CFA/II, and CFA/IV.

    Science.gov (United States)

    Ruan, Xiaosai; Knudsen, David E; Wollenberg, Katie M; Sack, David A; Zhang, Weiping

    2014-02-01

    Diarrhea is the second leading cause of death in children younger than 5 years and continues to be a major threat to global health. Enterotoxigenic Escherichia coli (ETEC) strains are the most common bacteria causing diarrhea in developing countries. ETEC strains are able to attach to host small intestinal epithelial cells by using bacterial colonization factor antigen (CFA) adhesins. This attachment helps to initiate the diarrheal disease. Vaccines that induce antiadhesin immunity to block adherence of ETEC strains that express immunologically heterogeneous CFA adhesins are expected to protect against ETEC diarrhea. In this study, we created a CFA multiepitope fusion antigen (MEFA) carrying representative epitopes of CFA/I, CFA/II (CS1, CS2, and CS3), and CFA/IV (CS4, CS5, and CS6), examined its immunogenicity in mice, and assessed the potential of this MEFA as an antiadhesin vaccine against ETEC. Mice intraperitoneally immunized with this CFA MEFA exhibited no adverse effects and developed immune responses to CFA/I, CFA/II, and CFA/IV adhesins. Moreover, after incubation with serum of the immunized mice, ETEC or E. coli strains expressing CFA/I, CFA/II, or CFA/IV adhesins were significantly inhibited in adherence to Caco-2 cells. Our results indicated this CFA MEFA elicited antibodies that not only cross-reacted to CFA/I, CFA/II and CFA/IV adhesins but also broadly inhibited adherence of E. coli strains expressing these seven adhesins and suggested that this CFA MEFA could be a candidate to induce broad-spectrum antiadhesin protection against ETEC diarrhea. Additionally, this antigen construction approach (creating an MEFA) may be generally used in vaccine development against heterogenic pathogens.

  19. 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.

  20. Genetical control of mitotic crossing over in yeast

    International Nuclear Information System (INIS)

    Fedorova, I.V.; Marfin, A.B.

    1982-01-01

    Lethal effect of 8 methoxypsoralen (8-MOP) and long-wave ultraviolet radiation (LUR) on diploid and haploid radiosensitive strains of yeast LSaccharomyces cerevisiae has been studied. It is shown that wild type diploids and homozygous with respect to locus rad 2 is considerably more stable than corresponding haploids, while diploid homozygous with respect to rad 54 locus is more sensitive than haploid. Use of the method of repeated irradiation permitted to study capability of radiosensitive diploids to remove 8 MOP-induced DNA photodamages-monoadducts. This process proceeds effectively in the wild type strain and rad 54 rad 54 diploid and was absent in rad 2 rad 2 diploid. Very strong recombinogenous effect of 8-MOP and LUR was discovered when studying mitotic segregation and crossing-over. It is also shown that rad 2 mutation increases slightly and rad 54 mutation decreases sharply frequency of recombination events in yeast cells. It is established by means of the repeated irradiation method that the main contribution to the 8 MOP and LUR recombinogenous effect is made with DNA sutures induced with these agents. Possible participation of different repair systems in the recombination processes induced with 8 MOP and LUR in yeast cells is discussed

  1. Changes in the relative population size of selected ruminal bacteria following an induced episode of acidosis in beef heifers receiving viable and non-viable active dried yeast.

    Science.gov (United States)

    Mohammed, R; Vyas, D; Yang, W Z; Beauchemin, K A

    2017-06-01

    To characterize the changes in the relative population size (RPS) of select ruminal bacteria and rumen fermentation variables in beef heifers supplemented with a strain of Saccharomyces cerevisiae as viable active dried (ADY) or killed dried (KDY) yeast following an induced episode of ruminal acidosis. Six ruminally cannulated beef heifers fed a diet consisting of 50% forage and 50% grain (dry matter basis) were used in a replicated 3 × 3 Latin square design with three 28-day periods. Treatments were: (i) control (CTRL; no yeast); (ii) ADY (4 g day -1 providing 10 10  CFU per g; AB Vista, UK); and (iii) KDY (4 g day -1 autoclaved ADY). The acidosis challenge was induced on day 22 and rumen samples were collected on day 15 (baseline; BASE), day 22 (challenge day; CHAL), and on day 29 (168th hour post acid challenge or recovery, REC) of each period. Over the study, duration of pH Yeast supplementation, irrespective of its viability, showed beneficial effects on ruminal pH variables in animals more susceptible to acidosis. Rumen microbial population was altered with the induction of severe acidosis. Most of the changes reverted back to baseline values during the recovery phase. Yeast supplementation reduced subacute rumen acidosis in the most susceptible cattle, but failed to attenuate severe acidosis induced by a grain challenge. The study provided valuable insight into the mechanism by which acidosis affects cattle performance. Individual animal variation in ruminal fermentation partly explained the variability in response to yeast supplementation in the study. © 2017 Her Majesty the Queen in Right of Canada. Journal of Applied Microbiology © 2017 The Society for Applied Microbiology.

  2. 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.

  3. Kex1 protease is involved in yeast cell death induced by defective N-glycosylation, acetic acid, and chronological aging.

    Science.gov (United States)

    Hauptmann, Peter; Lehle, Ludwig

    2008-07-04

    N-glycosylation in the endoplasmic reticulum is an essential protein modification and highly conserved in evolution from yeast to humans. The key step of this pathway is the transfer of the lipid-linked core oligosaccharide to the nascent polypeptide chain, catalyzed by the oligosaccharyltransferase complex. Temperature-sensitive oligosaccharyltransferase mutants of Saccharomyces cerevisiae at the restrictive temperature, such as wbp1-1, as well as wild-type cells in the presence of the N-glycosylation inhibitor tunicamycin display typical apoptotic phenotypes like nuclear condensation, DNA fragmentation, phosphatidylserine translocation, caspase-like activity, and reactive oxygen species accumulation. Since deletion of the yeast metacaspase YCA1 did not abrogate this death pathway, we postulated a different proteolytic process to be responsible. Here, we show that Kex1 protease is involved in the programmed cell death caused by defective N-glycosylation. Its disruption decreases caspase-like activity, production of reactive oxygen species, and fragmentation of mitochondria and, conversely, improves growth and survival of cells. Moreover, we demonstrate that Kex1 contributes also to the active cell death program induced by acetic acid stress or during chronological aging, suggesting that Kex1 plays a more general role in cellular suicide of yeast.

  4. Gamma irradiation induced ultrastructural changes in Paracoccidioides brasiliensis yeast cells

    International Nuclear Information System (INIS)

    Demicheli, Marina C.; Andrade, Antero S.R.; Goes, Alfredo Miranda

    2007-01-01

    Paracoccidioides brasiliensis is a thermally dimorphic fungus agent of paracoccidioidomycosis, a deep-seated systemic infection of humans with high prevalence in Latin America. Up to the moment no vaccine has still been reported. Ionizing radiation can be used to attenuate pathogens for vaccine development and we have successfully attenuated yeast cells of P. brasiliensis by gamma irradiation. The aim of the present study was to examine at ultrastructural level the effects of gamma irradiation attenuation on the morphology of P. brasiliensis yeast cells. P. brasiliensis (strain Pb-18) cultures were irradiated with a dose of 6.5 kGy. The irradiated cells were examined by scanning and also transmission electron microscopy. When examined two hours after the irradiation by scanning electron microscopy the 6.5 kGy irradiated cells presented deep folds or were collapsed. These lesions were reversible since examined 48 hours after irradiation the yeast have recovered the usual morphology. The transmission electron microscopy showed that the irradiated cells plasma membrane and cell wall were intact and preserved. Remarkable changes were found in the nucleus that was frequently in a very electrodense form. A extensive DNA fragmentation was produced by the gamma irradiation treatment. (author)

  5. Differential analysis of the inactivation of yeast cells induced by irradiation with various ionization densities

    International Nuclear Information System (INIS)

    Grundler, W.

    1979-03-01

    A quantitative investigation is presented on the radiation-induced inactivation of yeast cells in the first generations as a function of dose, repair, and various ionization densities. The study has been made to solve two main questions, i.e.: How do these cells reproduce, and how do they look like at the end of the investigation. Finding the answer to these questions, it was hoped, would lead to a description of survival in the colony test by defining the final fate of the cells which represent the stationary end state. The experiments were to clarify to what extent the dose-response curve yields only relatively general information on radiation-induced damage, or what kind of damage is mainly and best described. This supplementary information will help to improve the interpretation of many experiments having been made with this strain. (orig./MG) [de

  6. Immunologic proof of DNS irradiation damages and their repair in stationary yeast cells

    International Nuclear Information System (INIS)

    Waller, H.

    1980-08-01

    In rabbits an antiserum was produced by injecting UV-irradiated denaturated calf-thymus DNS; after inhibiting unspecific bindings, a specific serological reaction with UV-induced irradiation damages could be taken as present in this antiserum. By the ammonium sulphate precipitation as immunologic method of detection, after UV-irradiation the genesis of damages at certain sites in the DNS of different yeast lineages and their repair was observed. The elemination of UV-induced DNS damages was observed after an incubation in a nutrien medium, after photo-reactivation and after combining both therapeutic treatments. The following results were obtained: the detected DNS damage (number of induced dimeres/yeast genomes) had the same degree in the four yeast lineages. Apart from the excision-negative mutante 2094 for all yeast lineages a repair efficiency of 60% could be detected. All yeast lineages presented themselves as photographically to be reactivated; however, in all cases a DNS damage of 40 to 50% remained. The examinations for the specificity of antiserum against roentgenologically irradiated DNS led to the conclusion that the antibody population of the serum consisted mainly of immunoglobulines against unchanged DNS areas. A specific immunological reaction of only about 10% could be achieved. (orig./MG) [de

  7. rBCG30-induced immunity and cross-protection against Mycobacterium leprae challenge are enhanced by boosting with the Mycobacterium tuberculosis 30-kilodalton antigen 85B.

    Science.gov (United States)

    Gillis, Thomas P; Tullius, Michael V; Horwitz, Marcus A

    2014-09-01

    Leprosy remains a major global health problem and typically occurs in regions in which tuberculosis is endemic. Vaccines are needed that protect against both infections and do so better than the suboptimal Mycobacterium bovis BCG vaccine. Here, we evaluated rBCG30, a vaccine previously demonstrated to induce protection superior to that of BCG against Mycobacterium tuberculosis and Mycobacterium bovis challenge in animal models, for efficacy against Mycobacterium leprae challenge in a murine model of leprosy. rBCG30 overexpresses the M. tuberculosis 30-kDa major secretory protein antigen 85B, which is 85% homologous with the M. leprae homolog (r30ML). Mice were sham immunized or immunized intradermally with BCG or rBCG30 and challenged 2.5 months later by injection of viable M. leprae into each hind footpad. After 7 months, vaccine efficacy was assessed by enumerating the M. leprae bacteria per footpad. Both BCG and rBCG30 induced significant protection against M. leprae challenge. In the one experiment in which a comparison between BCG and rBCG30 was feasible, rBCG30 induced significantly greater protection than did BCG. Immunization of mice with purified M. tuberculosis or M. leprae antigen 85B also induced protection against M. leprae challenge but less so than BCG or rBCG30. Notably, boosting rBCG30 with M. tuberculosis antigen 85B significantly enhanced r30ML-specific immune responses, substantially more so than boosting BCG, and significantly augmented protection against M. leprae challenge. Thus, rBCG30, a vaccine that induces improved protection against M. tuberculosis, induces cross-protection against M. leprae that is comparable or potentially superior to that induced by BCG, and boosting rBCG30 with antigen 85B further enhances immune responses and protective efficacy. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  8. Ablation of synovial pannus using microbubble-mediated ultrasonic cavitation in antigen-induced arthritis in rabbits.

    Science.gov (United States)

    Qiu, Li; Jiang, Yong; Zhang, Lingyan; Wang, Lei; Luo, Yan

    2012-12-01

    To investigate the ablative effectiveness of microbubble-mediated ultrasonic cavitation for treating synovial pannus and to determine a potential mechanism using the antigen-induced arthritis model (AIA). Ultrasonic ablation was performed on the knee joints of AIA rabbits using optimal ultrasonic ablative parameters. Rabbits with antigen-induced arthritis were randomly assigned to 4 groups: (1) the ultrasound (US) + microbubble group; (2) the US only group; (3) the microbubble only group, and (4) the control group. At 1 h and 14 days after the first ablation, contrast-enhanced ultrasonography (CEUS) monitoring and pathology synovitis score were used to evaluate the therapeutic effects. Synovial necrosis and microvascular changes were also measured. After the ablation treatment, the thickness of synovium and parameters of time intensity curve including derived peak intensity and area under curve were measured using CEUS, and the pathology synovitis score in the ultrasound + microbubble group was significantly lower than that found in the remaining groups. No damage was observed in the surrounding normal tissues. The mechanism underlying the ultrasonic ablation was related to microthrombosis and microvascular rupture that resulted in synovial necrosis. The results suggest that microbubble-mediated ultrasonic cavitation should be applied as a non-invasive strategy for the treatment of synovial pannus in arthritis under optimal conditions.

  9. Reduction-sensitive dextran nanogels aimed for intracellular delivery of antigens

    NARCIS (Netherlands)

    Li, Dandan; Kordalivand, Neda; Fransen, Marieke F.; Ossendorp, Ferry; Raemdonck, Koen; Vermonden, Tina; Hennink, Wim E.; Van Nostrum, Cornelus F.

    2015-01-01

    Targeting of antigens to dendritic cells (DCs) to induce strong cellular immune response can be established by loading in a nano-sized carrier and keeping the antigen associated with the particles until they are internalized by DCs. In the present study, a model antigen (ovalbumin, OVA) is

  10. Yeast Extract Promotes Cell Growth and Induces Production of Polyvinyl Alcohol-Degrading Enzymes

    Directory of Open Access Journals (Sweden)

    Min Li

    2011-01-01

    Full Text Available Polyvinyl alcohol-degrading enzymes (PVAases have a great potential in bio-desizing processes for its low environmental impact and low energy consumption. In this study, the effect of yeast extract on PVAases production was investigated. A strategy of four-point yeast extract addition was developed and applied to maximize cell growth and PVAases production. As a result, the maximum dry cell weight achieved was 1.48 g/L and the corresponding PVAases activity was 2.99 U/mL, which are 46.5% and 176.8% higher than the control, respectively. Applying this strategy in a 7 L fermentor increased PVAases activity to 3.41 U/mL. Three amino acids (glycine, serine, and tyrosine in yeast extract play a central role in the production of PVAases. These results suggest that the new strategy of four-point yeast extract addition could benefit PVAases production.

  11. Assessment of pheromone production and response in fission yeast by a halo test of induced sporulation

    DEFF Research Database (Denmark)

    Egel, R; Willer, M; Kjaerulff, S

    1994-01-01

    We describe a rapid, sensitive and semi-quantitative plate assay for monitoring pheromone activity in the fission yeast Schizosaccharomyces pombe. It is based on the observation that meiosis requires stimulation by pheromone and exploits diploid strains that will only sporulate after addition...... of exogenous pheromone. The tester strains are heterozygous for mating type, are non-switching, and are mutated in one of the early subfunctions (either mat1-Mc or mat1-Pc), so that meiosis is only induced after exposure to exogenous pheromone (M-factor or P-factor, respectively). Pheromone activity...

  12. Protective immunity induced in mice by F8.1 and F8.2 antigens purified from Schistosoma mansoni eggs

    Directory of Open Access Journals (Sweden)

    Claudia Campra Ferreira

    1998-01-01

    Full Text Available Schistosoma mansoni soluble egg antigens (SEA were fractionated by isoelectric focusing, resulting in 20 components, characterized by pH, absorbance and protein concentration. The higher absorbance fractions were submitted to electrophoresis, and fraction 8 (F8 presented a specific pattern of bands on its isoelectric point. Protein 3 was observed only on F8, and so, it was utilized to rabbit immunization, in order to evaluate its capacity of inducing protective immunity. IgG antibodies from rabbit anti-F8 serum were coupled to Sepharose, and used to obtain the specific antigen by affinity chromatography. This antigen, submitted to electrophoresis, presented two proteic bands (F8.1 and F8.2, which were transferred to nitrocellulose membrane (PVDF and sequenciated. The homology of F8.2 to known proteins was determined using the Basic Local Alignment Search Tool program (BLASTp. Significant homologies were obtained for the rabbit cytosolic Ca2+ uptake inhibitor, and for the bird a1-proteinase inhibitor. Immunization of mice with F8.1 and F8.2, in the presence of Corynebacterium parvum and Al(OH3 as adjuvant, induced a significant protection degree against challenge infection, as observed by the decrease on worm burden recovered from portal system.

  13. Prevalence, risk factors, and impact of isolated antibody to hepatitis B core antigen and occult hepatitis B virus infection in HIV-1-infected pregnant women.

    Science.gov (United States)

    Khamduang, Woottichai; Ngo-Giang-Huong, Nicole; Gaudy-Graffin, Catherine; Jourdain, Gonzague; Suwankornsakul, Weerapong; Jarupanich, Tapnarong; Chalermpolprapa, Veeradate; Nanta, Sirisak; Puarattana-Aroonkorn, Noossara; Tonmat, Sakchai; Lallemant, Marc; Goudeau, Alain; Sirirungsi, Wasna

    2013-06-01

    Prevalence and risk factors for isolated antibody to hepatitis B core antigen (anti-HBc) and occult hepatitis B virus (HBV) infection are not well known in human immunodeficiency virus type 1 (HIV-1)-infected pregnant women. It is unclear if women with occult infections are at risk of transmitting HBV to their infants. HIV-1-infected and HBV surface antigen (HBsAg)-negative pregnant women were tested for antibody to HBsAg (anti-HBs) and anti-HBc using enzyme immunoassay. Women with isolated anti-HBc were assessed for occult HBV infection, defined as HBV DNA levels >15 IU/mL, using the Abbott RealTime HBV DNA assay. Infants born to women with isolated anti-HBc and detectable HBV DNA were tested at 4 months of age for HBV DNA. Logistic regression analysis was used to identify factors associated with isolated anti-HBc and occult HBV infection. Among 1812 HIV-infected pregnant women, 1682 were HBsAg negative. Fourteen percent (95% confidence interval [CI], 12%-15%) of HBsAg-negative women had an isolated anti-HBc that was independently associated with low CD4 count, age >35 years, birth in northern Thailand, and positive anti-hepatitis C virus serology. Occult HBV infection was identified in 24% (95% CI, 18%-30%) of women with isolated anti-HBc, representing 2.6% (95% CI, 1.9%-3.5%) of HIV-1-infected pregnant women, and was inversely associated with HIV RNA levels. None of the women with isolated anti-HBc and occult HBV infection transmitted HBV to their infants. HIV-1-infected pregnant women with isolated anti-HBc and occult HBV infection have very low HBV DNA levels and are thus at very low risk to transmit HBV to their infants.

  14. Timing of the uv mutagenesis in yeast: a pedigree analysis of induced recessive mutation

    International Nuclear Information System (INIS)

    James, A.P.; Kilbey, B.J.

    1977-01-01

    The mechanism of uv-induced mutation in eukaryotes was studied in individual yeast cells by a procedure that combined pedigree analysis and tetrad analysis. The technique involved the induction of recessive lethals and semilethals in G1 diploid cells. Induced frequencies were 25 and 61% at survival levels of 90 and 77%, respectively. No evidence of gross chromosome aberrations was detected. Recessive mutations that affect only one strand or that affect both strands of the DNA molecule are induced much at random among a population of cells, and both types can occur within the same cell. However, the data confirm that two-strand mutations are in the majority after a low level of irradiation. The simplest explanation involves a mechanism whereby most mutations are fixed in both strands prior to the first round of post-irradiation DNA replication. The recessive mutational consequences of irradiation are exhausted at the conclusion of the first post-irradiation cell division, although dominant-lethal sectoring continues at a high level through the second post-irradiation division. It is concluded that pyrimidine dimers that persist to the second round of DNA replication are rare or ineffective

  15. The timing of UV mutagenesis in yeast: a pedigree analysis of induced recessive mutation.

    Science.gov (United States)

    James, A P; Kilbey, B J

    1977-10-01

    The mechanism of UV-induced mutation in eukaryotes was studied in individual yeast cells by a procedure that combined pedigree analysis and tetrad analysis. The technique involved the induction of recessive lethals and semilethals in G1 diploid cells. Induced frequencies were 25 and 61 percent at survival levels of 90 and 77 percent, respectively. No evidence of gross chromosome aberrations was detected. Recessive mutations that affect only one strand or that affect both strands of the DNA molecule are induced much at random among a population of cells, and both types can occur within the same cell. However, the data confirm that two-strand mutations are in the majority after a low level of irradiation. The simplest explanation involves a mechanism whereby most mutations are fixed in both strands prior to the first round of post-irradiation DNA replication. The recessive mutational consequences of irradiation are exhausted at the conclusion of the first post-irradiation cell division, although dominant-lethal sectoring continues at a high level through the second post-irradiation division. It is concluded that pyrimidine dimers that persist to the second round of DNA replication are rare or ineffective.

  16. Enhanced vaccine-induced CD8+ T cell responses to malaria antigen ME-TRAP by fusion to MHC class ii invariant chain.

    Directory of Open Access Journals (Sweden)

    Alexandra J Spencer

    Full Text Available The orthodox role of the invariant chain (CD74; Ii is in antigen presentation to CD4+ T cells, but enhanced CD8+ T cells responses have been reported after vaccination with vectored viral vaccines encoding a fusion of Ii to the antigen of interest. In this study we assessed whether fusion of the malarial antigen, ME-TRAP, to Ii could increase the vaccine-induced CD8+ T cell response. Following single or heterologous prime-boost vaccination of mice with a recombinant chimpanzee adenovirus vector, ChAd63, or recombinant modified vaccinia virus Ankara (MVA, higher frequencies of antigen-specific CD4+ and CD8+ T cells were observed, with the largest increases observed following a ChAd63-MVA heterologous prime-boost regimen. Studies in non-human primates confirmed the ability of Ii-fusion to augment the T cell response, where a 4-fold increase was maintained up to 11 weeks after the MVA boost. Of the numerous different approaches explored to increase vectored vaccine induced immunogenicity over the years, fusion to the invariant chain showed a consistent enhancement in CD8+ T cell responses across different animal species and may therefore find application in the development of vaccines against human malaria and other diseases where high levels of cell-mediated immunity are required.

  17. Peg-interferon plus nucleotide analogue treatment versus no treatment in patients with chronic hepatitis B with a low viral load: a randomised controlled, open-label trial

    NARCIS (Netherlands)

    de Niet, Annikki; Jansen, Louis; Stelma, Femke; Willemse, Sophie B.; Kuiken, Sjoerd D.; Weijer, Sebastiaan; van Nieuwkerk, Carin M. J.; Zaaijer, Hans L.; Molenkamp, Richard; Takkenberg, R. Bart; Koot, Maarten; Verheij, Joanne; Beuers, Ulrich; Reesink, Hendrik W.

    2017-01-01

    Antiviral treatment is currently not recommended for patients with chronic hepatitis B with a low viral load. However, they might benefit from acquiring a functional cure (hepatitis B surface antigen [HBsAg] loss with or without formation of antibodies against hepatitis B surface antigen

  18. Multiepitope Fusion Antigen Induces Broadly Protective Antibodies That Prevent Adherence of Escherichia coli Strains Expressing Colonization Factor Antigen I (CFA/I), CFA/II, and CFA/IV

    OpenAIRE

    Ruan, Xiaosai; Knudsen, David E.; Wollenberg, Katie M.; Sack, David A.; Zhang, Weiping

    2014-01-01

    Diarrhea is the second leading cause of death in children younger than 5 years and continues to be a major threat to global health. Enterotoxigenic Escherichia coli (ETEC) strains are the most common bacteria causing diarrhea in developing countries. ETEC strains are able to attach to host small intestinal epithelial cells by using bacterial colonization factor antigen (CFA) adhesins. This attachment helps to initiate the diarrheal disease. Vaccines that induce antiadhesin immunity to block a...

  19. Study on immobilized yeast cells with hydrophilic polymer carrier by radiation-induced copolymerization

    International Nuclear Information System (INIS)

    Li Zhengkui; Zhang Bosen

    1993-01-01

    Various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) are copolymerized by radiation technique at low temperature (-78 degree C) and several kinds of copolymer carriers were obtained. Yeast cells are immobilized through adhesion and multiplication of yeast cells themselves on these carriers. The ethanol productivity of immobilized yeast cells with these carriers was related to the monomer composition and water content of copolymer carriers and the optimum monomer composition was 20%:10% in poly (HEA-M23G). In this case, the ethanol productivity of immobilized yeast cells was 26 mg/(ml · h), which was 4 times as high as that of free cells. Effect of adding crosslinking reagent (4G) in lower monomer composition of poly(HEA-M23G) on the ethanol productivity of immobilized cells was better than that in higher one in this work

  20. Milk-induced eczema is associated with the expansion of T cells expressing cutaneous lymphocyte antigen.

    Science.gov (United States)

    Abernathy-Carver, K J; Sampson, H A; Picker, L J; Leung, D Y

    1995-02-01

    The extravasation of T cells at sites of inflammation is critically dependent on the activity of homing receptors (HR) involved in endothelial cell recognition and binding. Two such HR (the cutaneous lymphocyte antigen [CLA] and L-selectin) have been shown to be selectively involved in T cell migration to skin and peripheral lymph nodes, respectively. This study was designed to assess the relationship between the organ specificity of an allergic reaction to food and the expression of HR on T cells activated in vitro by the relevant food allergen. Peripheral blood mononuclear cells were isolated from seven milk allergic children with a history of eczema when exposed to milk. All patients had a positive prick skin test and double-blind placebo-controlled food challenge to milk. 10 children with either allergic eosinophilic gastroenteritis or milk-induced enterocolitis and 8 nonatopic adults served as controls. Five-parameter flow cytometry using monoclonal antibodies was used for detection of the specific HR on freshly isolated T cells versus T cell blasts induced by a 6-d incubation with casein, as compared with Candida albicans. After in vitro stimulation with casein, but not C. albicans, patients with milk allergy and atopic dermatitis had a significantly greater percentage of CLA+ T cells (P < 0.01) than controls with milk-induced enterocolitis, allergic eosinophilic gastroenteritis, or nonatopic healthy controls. In contrast, the percentage of L-selectin-expressing T cells did not differ significantly between these groups. These data suggest that after casein stimulation allergic patients with milk-induced skin disease have an expanded population of CLA+ T cells, as compared with nonatopics or allergic patients without skin involvement. We postulate that heterogeneity in the regulation of HR expression on antigen-specific T cells may play a role in determining sites of involvement in tissue-directed allergic responses.

  1. 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.

  2. Glycosylceramide modifies the flavor and metabolic characteristics of sake yeast

    Directory of Open Access Journals (Sweden)

    Jannatul Ferdouse

    2018-05-01

    Full Text Available In the manufacture of sake, Japanese traditional rice wine, sake yeast is fermented with koji, which is steamed rice fermented with the non-pathogenic fungus Aspergillus oryzae. During fermentation, sake yeast requires lipids, such as unsaturated fatty acids and sterols, in addition to substances provided by koji enzymes for fermentation. However, the role of sphingolipids on the brewing characteristics of sake yeast has not been studied. In this study, we revealed that glycosylceramide, one of the sphingolipids abundant in koji, affects yeast fermentation. The addition of soy, A. oryzae, and Grifola frondosa glycosylceramide conferred a similar effect on the flavor profiles of sake yeast. In particular, the addition of A. oryzae and G. frondosa glycosylceramide were very similar in terms of the decreases in ethyl caprylate and ethyl 9-decenoate. The addition of soy glycosylceramide induced metabolic changes to sake yeast such as a decrease in glucose, increases in ethanol and glycerol and changes in several amino acids and organic acids concentrations. Tricarboxylic acid (TCA cycle, pyruvate metabolism, starch and sucrose metabolism, and glycerolipid metabolism were overrepresented in the cultures incubated with sake yeast and soy glycosylceramide. This is the first study of the effect of glycosylceramide on the flavor and metabolic profile of sake yeast.

  3. Glycosylceramide modifies the flavor and metabolic characteristics of sake yeast.

    Science.gov (United States)

    Ferdouse, Jannatul; Yamamoto, Yuki; Taguchi, Seiga; Yoshizaki, Yumiko; Takamine, Kazunori; Kitagaki, Hiroshi

    2018-01-01

    In the manufacture of sake, Japanese traditional rice wine, sake yeast is fermented with koji, which is steamed rice fermented with the non-pathogenic fungus Aspergillus oryzae . During fermentation, sake yeast requires lipids, such as unsaturated fatty acids and sterols, in addition to substances provided by koji enzymes for fermentation. However, the role of sphingolipids on the brewing characteristics of sake yeast has not been studied. In this study, we revealed that glycosylceramide, one of the sphingolipids abundant in koji, affects yeast fermentation. The addition of soy, A. oryzae , and Grifola frondosa glycosylceramide conferred a similar effect on the flavor profiles of sake yeast. In particular, the addition of A. oryzae and G. frondosa glycosylceramide were very similar in terms of the decreases in ethyl caprylate and ethyl 9-decenoate. The addition of soy glycosylceramide induced metabolic changes to sake yeast such as a decrease in glucose, increases in ethanol and glycerol and changes in several amino acids and organic acids concentrations. Tricarboxylic acid (TCA) cycle, pyruvate metabolism, starch and sucrose metabolism, and glycerolipid metabolism were overrepresented in the cultures incubated with sake yeast and soy glycosylceramide. This is the first study of the effect of glycosylceramide on the flavor and metabolic profile of sake yeast.

  4. Molecular nature of forvard gene mutations induced by γ- and UV-irradiation ip the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Ivanov, E.L.; Koval'tsova, S.V.; Korolev, V.G.

    1983-01-01

    Gamma and UV-radiation induce the following mutation spectra in the ADE2 gene of Saccharomyces cerevisial yeast respectively: 27 and 41% of GTs→AT transitions, 8 and 11% of AT→GTs transitions, 59 and 40% transversions, 6 and 8% mutations of the reading fame shift type. The results obtained prove the presence of specific nature of UV rays in respect to induction of GTs→AT transitions. The experimental data are discussed from the point of view of studying molecular mechanisms of radiation mutagenesis

  5. Cyanohydrin reactions enhance glycolytic oscillations in yeast

    DEFF Research Database (Denmark)

    Hald, Bjørn Olav; Nielsen, Astrid Gram; Tortzen, Christian

    2015-01-01

    Synchronous metabolic oscillations can be induced in yeast by addition of glucose and removal of extracellular acetaldehyde (ACAx). Compared to other means of ACAx removal, cyanide robustly induces oscillations, indicating additional cyanide reactions besides ACA to lactonitrile conversion. Here......: a) by reducing [ACAx] relative to oscillation amplitude, b) by targeting multiple intracellular carbonyl compounds during fermentation, and c) by acting as a phase resetting stimulus....

  6. Seroprevalence of Human Immunodeficiency Virus, Hepatitis B ...

    African Journals Online (AJOL)

    surface antigen (HBsAg), syphilis and HCV from the antenatal records. The data were extracted by two trained assistants. Hepatitis B surface antigen and antibodies to HCV were determined using Clinotech diagnostic enzyme linked immunosorbent assay (ELISA) test kits (Clinotech Laboratories,. USA; batch/lot no. for ...

  7. Hepatitis B virus core antigen determines viral persistence in a C57BL/6 mouse model.

    Science.gov (United States)

    Lin, Yi-Jiun; Huang, Li-Rung; Yang, Hung-Chih; Tzeng, Horng-Tay; Hsu, Ping-Ning; Wu, Hui-Lin; Chen, Pei-Jer; Chen, Ding-Shinn

    2010-05-18

    We recently developed a mouse model of hepatitis B virus (HBV) persistence, in which a single i.v. hydrodynamic injection of HBV DNA to C57BL/6 mice allows HBV replication and induces a partial immune response, so that about 20-30% of the mice carry HBV for more than 6 months. The model was used to identify the viral antigen crucial for HBV persistence. We knocked out individual HBV genes by introducing a premature termination codon to the HBV core, HBeAg, HBx, and polymerase ORFs. The specific-gene-deficient HBV mutants were hydrodynamically injected into mice and the HBV profiles of the mice were monitored. About 90% of the mice that received the HBcAg-mutated HBV plasmid exhibited high levels of hepatitis B surface antigenemia and maintained HBsAg expression for more than 6 months after injection. To map the region of HBcAg essential for viral clearance, we constructed a set of serial HBcAg deletion mutants for hydrodynamic injection. We localized the essential region of HBcAg to the carboxyl terminus, specifically to the 10 terminal amino acids (HBcAg176-185). The majority of mice receiving this HBV mutant DNA did not elicit a proper HBcAg-specific IFN-gamma response and expressed HBV virions for 6 months. These results indicate that the immune response triggered in mice by HBcAg during exposure to HBV is important in determining HBV persistence.

  8. Mechanisms of uv mutagenesis in yeast and E. coli

    International Nuclear Information System (INIS)

    Lawrence, C.; Christensen, R.; Christensen, J.R.; O'Brien, T.

    1983-01-01

    Experiments investigating ultraviolet light mutagenesis in either bakers' yeast, Saccharomyces cerevisiae, or E. coli have led to the following conclusions. First, cyclobutane pyrimidine dimers cause most mutations in both organisms; pyrimidine adducts, such as PyC, can account at best for only a small proportion. 86 percent of forward mutations induced at the E. coli lacI locus can be abolished by photoreactivation under conditions which do not alter the level of recA induction. About 75 percent of the forward mutations induced at the CAN1 locus of yeast could be removed by photoreactivation, a value that lies within the range observed previously for the reversion of CYC1 alleles (60 percent - 97 percent). Second, about 10 percent of the lacI forward mutations are untargeted, a smaller fraction than found previously for cycl-91 reversion in yeast. It is not yet clear whether the two species are really different in this respect, of whether the cycl-91 reversion site is a typical of the yeast genome at large. Third, analysis of reversion frequencies of 20 mutant alleles suggests that about 10 to 25 percent of all replication errors produced by mutagenic mechanisms in uv-irradiated yeast involve additions or deletions of base-pairs, indicating that error-prone repair does not just produce substitutions. Last, the REV1 locus in yeast is concerned with the induction of frameshift mutations at some, but not all, genetic sites, just as found previously for substitution mutations. The function of the REV3 gene is more widely, though not universally, required while the function of the RAD6 gene, like that of the recA locus in E. coli, appears to be necessary for all kinds of uv mutagenesis. E coli genes comparable to REV1 and REV3 have not yet been described; conversely, there does not yet appear to be a yeast equivalent of umuC

  9. Mechanisms of uv mutagenesis in yeast and E. coli

    International Nuclear Information System (INIS)

    Lawrence, C.; Christensen, R.; Christensen, J.R.; O'Brien, T.

    1983-01-01

    Experiments investigating ultraviolet light mutagenesis in either bakers' yeast, Saccharomyces cerevisiae, or E. coli have led to the following conclusions. First, cyclobutane pyrimidine dimers cause most mutations in both organisms; pyrimidine adducts, such as PyC, can account at best for only a small proportion. Eighty-six percent of forward mutations induced at the E. coli lacI locus can be abolished by photoreactivation under conditions which do not alter the level of recA induction. About 75 percent of the forward mutations induced at the CAN1 locus of yeast could be removed by photoreactivation, a value that lies within the range observed previously for the reversion of CYC1 alleles (60 percent - 97 percent). Second, about 10 percent of the lacI forward mutations are untargeted, a smaller fraction than found previously for cycl1-91 reversion in yeast. It is not yet clear whether the two species are really different in this respect, or whether the cyc1-91 reversion site is atypical of the yeast genome at large. Third, analysis of reversion frequencies of 20 mutant alleles suggests that about 10 - 25 percent of all replication errors produced by mutagenic mechanisms in UV-irradiated yeast involve additions or deletions of base-pairs, indicating that error-prone repair does not just produce substitutions. Last, the REV1 locus in yeast is concerned with the induction of frameshift mutations at some, but not all, genetic sites, just as found previously for substitution mutations. The function of the REV3 gene is more widely, though not universally, required while the function of the RAD6 gene, like that of the recA locus in E. coli, appears to be necessary for all kinds of UV mutagenesis. E. coli genes comparable to REV1 and REV3 have not yet been described, conversely, there does not yet appear to be a yeast equivalent of umuC. 13 references, 4 tables

  10. Native Mass Spectrometry, Ion mobility, and Collision-Induced Unfolding Categorize Malaria Antigen/Antibody Binding

    Science.gov (United States)

    Huang, Yining; Salinas, Nichole D.; Chen, Edwin; Tolia, Niraj H.; Gross, Michael L.

    2017-09-01

    Plasmodium vivax Duffy Binding Protein (PvDBP) is a promising vaccine candidate for P. vivax malaria. Recently, we reported the epitopes on PvDBP region II (PvDBP-II) for three inhibitory monoclonal antibodies (2D10, 2H2, and 2C6). In this communication, we describe the combination of native mass spectrometry and ion mobility (IM) with collision induced unfolding (CIU) to study the conformation and stabilities of three malarial antigen-antibody complexes. These complexes, when collisionally activated, undergo conformational changes that depend on the location of the epitope. CIU patterns for PvDBP-II in complex with antibody 2D10 and 2H2 are highly similar, indicating comparable binding topology and stability. A different CIU fingerprint is observed for PvDBP-II/2C6, indicating that 2C6 binds to PvDBP-II on an epitope different from 2D10 and 2H2. This work supports the use of CIU as a means of classifying antigen-antibody complexes by their epitope maps in a high throughput screening workflow. [Figure not available: see fulltext.

  11. Distinct Domestication Trajectories in Top-Fermenting Beer Yeasts and Wine Yeasts.

    Science.gov (United States)

    Gonçalves, Margarida; Pontes, Ana; Almeida, Pedro; Barbosa, Raquel; Serra, Marta; Libkind, Diego; Hutzler, Mathias; Gonçalves, Paula; Sampaio, José Paulo

    2016-10-24

    Beer is one of the oldest alcoholic beverages and is produced by the fermentation of sugars derived from starches present in cereal grains. Contrary to lager beers, made by bottom-fermenting strains of Saccharomyces pastorianus, a hybrid yeast, ale beers are closer to the ancient beer type and are fermented by S. cerevisiae, a top-fermenting yeast. Here, we use population genomics to investigate (1) the closest relatives of top-fermenting beer yeasts; (2) whether top-fermenting yeasts represent an independent domestication event separate from those already described; (3) whether single or multiple beer yeast domestication events can be inferred; and (4) whether top-fermenting yeasts represent non-recombinant or recombinant lineages. Our results revealed that top-fermenting beer yeasts are polyphyletic, with a main clade composed of at least three subgroups, dominantly represented by the German, British, and wheat beer strains. Other beer strains were phylogenetically close to sake, wine, or bread yeasts. We detected genetic signatures of beer yeast domestication by investigating genes previously linked to brewing and using genome-wide scans. We propose that the emergence of the main clade of beer yeasts is related with a domestication event distinct from the previously known cases of wine and sake yeast domestication. The nucleotide diversity of the main beer clade more than doubled that of wine yeasts, which might be a consequence of fundamental differences in the modes of beer and wine yeast domestication. The higher diversity of beer strains could be due to the more intense and different selection regimes associated to brewing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Expression profiles of mRNA after exposure yeast and rice to heavy-ion radiation

    International Nuclear Information System (INIS)

    Iwahashi, Hitoshi; Mizukami, Satomi; Nojima, Kumie

    2005-01-01

    We have studied expression profiles of mRNA after exposure yeast cells to heavy-ion radiation. Yeast cells was exposed by heavy-ion radiation with the levels of 6, 12, 25, 50, and 100 Gy. We could confirm the reproducibility of physiological state of yeast cells under the experimental conditions by DNA microarray. We could also confirm the reproducibility of viability of yeast cells after exposure to heavy-ion radiation. We thus applied yeast cells exposed with 25 Gy was applied to DNA microarray analysis. The strongly induced genes were HUG1 RAR4 RNR2 for DNA repairing genes and GLC3 GSY1 for energy metabolism genes. (author)

  13. Prions in yeast

    OpenAIRE

    Bezdíčka, Martin

    2013-01-01

    The thesis describes yeast prions and their biological effects on yeast in general. It defines the basic characteristics of yeast prions, that distinguish prions from other proteins. The thesis introduces various possibilities of prion formation, and propagation as well as specific types of yeast prions, including various functions of most studied types of prions. The thesis also focuses on chaperones that affect the state of yeast prions in cells. Lastly, the thesis indicates similarities be...

  14. Ligation of major histocompatibility complex class I antigens (MHC-I) prevents apoptosis induced by Fas or SAPK/JNK activation in T-lymphoma cells

    DEFF Research Database (Denmark)

    Lamberth, K; Claesson, M H

    2001-01-01

    Early apoptosis in Jurkat T-lymphoma cells was induced by agonistic anti-Fas Ab or by anisomycin which activates the stress kinases SAPK/JNK. Apoptosis was inhibited by ligation of major histocompatibility complex class I antigens (MHC-I). MHC-I ligation induced upregulation of the anti-apoptotic......Early apoptosis in Jurkat T-lymphoma cells was induced by agonistic anti-Fas Ab or by anisomycin which activates the stress kinases SAPK/JNK. Apoptosis was inhibited by ligation of major histocompatibility complex class I antigens (MHC-I). MHC-I ligation induced upregulation of the anti......-apoptotic Bcl-2 protein and stabilized the mitochondrial membrane potential (Deltapsim). MHC-I ligation also prevented downregulation of Bcl-2 and destabilization of Deltapsim induced by anti-Fas Ab treatment or anisomycin exposure. Studies on three different Jurkat cell mutants deficient for src p56(lck), ZAP......-70 kinase, or TCR/CD3 gamma-chain showed that the cells undergo apoptosis after Fas ligation. Anisomycin exposure induced apoptosis in the src p56(lck)-deficient cell line but not in the two other mutant cell lines. Simultaneous cross-linking of MHC-I and Fas ligation inhibited apoptosis in the ZAP...

  15. A vaccine grade of yeast Saccharomyces cerevisiae expressing mammalian myostatin

    Directory of Open Access Journals (Sweden)

    Zhang Tingting

    2012-12-01

    Full Text Available Abstract Background Yeast Saccharomyces cerevisiae is a widely-used system for protein expression. We previously showed that heat-killed whole recombinant yeast vaccine expressing mammalian myostatin can modulate myostatin function in mice, resulting in increase of body weight and muscle composition in these animals. Foreign DNA introduced into yeast cells can be lost soon unless cells are continuously cultured in selection media, which usually contain antibiotics. For cost and safety concerns, it is essential to optimize conditions to produce quality food and pharmaceutical products. Results We developed a simple but effective method to engineer a yeast strain stably expressing mammalian myostatin. This method utilized high-copy-number integration of myostatin gene into the ribosomal DNA of Saccharomyces cerevisiae. In the final step, antibiotic selection marker was removed using the Cre-LoxP system to minimize any possible side-effects for animals. The resulting yeast strain can be maintained in rich culture media and stably express mammalian myostatin for two years. Oral administration of the recombinant yeast was able to induce immune response to myostatin and modulated the body weight of mice. Conclusions Establishment of such yeast strain is a step further toward transformation of yeast cells into edible vaccine to improve meat production in farm animals and treat human muscle-wasting diseases in the future.

  16. Evaluation of the protection induced by the immunization with radioiodinated yeast cells of Paracoccidioides brasiliensis in animal model

    International Nuclear Information System (INIS)

    Martins, Estefania Mara do Nascimento

    2007-01-01

    Paracoccidioides brasiliensis is fungus agent of paracoccidioidomycosis (PCM), a chronic systemic disease prevalent in Latin American. To date, there is no effective vaccine. The potential of gamma radiation for pathogens attenuation and vaccine development was explored in this work. In our laboratory were developed yeast cells of P. brasiliensis attenuated by gamma radiation, which lose the reproductive ability, while retaining the morphology, the synthesis and secretion of proteins, the oxidative metabolism and the expression of the antigens present in the native yeast. The aim of the present work was to evaluate the protection elicited by the immunization with this cells in animal model. The virulence attenuated was evaluated in BALB/c and Nude-Nude mice. The protector effect was evaluated in BALB/c mice groups immunized once or twice. Each group was divided in three sub groups that were challenge 30, 45 or 60 days after the immunization. The mice were sacrificed 30 and 90 days after challenge. The removed organs were used for colony forming units (CFU's) recover, histopathological analysis and cytokine determination. The sera were collected weekly to evaluate the IgG antibody titers and the IgG1 and IgG2a pattern in the course of infection. To evaluate the type of elicited immune response the cytokines IFN - γ, TNF - α, IL - 10 and IL - 5 were determined by real time PCR. The radio attenuated yeast loses its virulence since fails in producing infection in BALB/c and Nude-Nude mice. No CFU's were recovered neither histological changes observed in the mice infected with the radio attenuated cells. The mice infected with the not irradiated P. brasiliensis showed a high level of antibody production while the infection with the radio attenuated yeast did not significantly change the antibody level. The mice infected with the radio attenuated yeast presented an increase in the IFN - γ and TNF - α production and an inhibition of the IL-10 synthesis, indicating a

  17. CHARACTERIZATION OF THE ALKANE-INDUCIBLE CYTOCHROME P450 (P450ALK) GENE FROM THE YEAST CANDIDA TROPICALIS: IDENTIFICATION OF A NEW P450 FAMILY

    Science.gov (United States)

    The P450alk gene, which is inducible by the assimilation of alkane in Candida tropicalis, was sequenced and characterized. Structural features described in promoter and terminator regions of Saccharomyces yeast genes are present in the P450alk gene and some particular structures ...

  18. Hepatitis B virus e antigen induces activation of rat hepatic stellate cells

    International Nuclear Information System (INIS)

    Zan, Yanlu; Zhang, Yuxia; Tien, Po

    2013-01-01

    Highlights: •HBeAg expression in HSCs induced production of ECM protein and liver fibrotic markers. •The activation and proliferation of HSCs were mediated by TGF-β. •HBeAg protein purified from cell medium directly activated HSCs. -- Abstract: Chronic hepatitis B virus infection is a major cause of hepatic fibrosis, leading to liver cirrhosis and hepatocellular carcinoma. Hepatitis B virus e antigen (HBeAg) is an accessory protein of HBV, not required for viral replication but important for natural infection in vivo. Hepatic stellate cells (HSCs) are the major producers of excessive extracellular matrix during liver fibrogenesis. Therefore, we examined the influence of HBeAg on HSCs. The rat HSC line HSC-T6 was transfected with HBeAg plasmids, and expression of α-smooth muscle actin, collagen I, transforming growth factor-β1 (TGF-β), and tissue inhibitors of metalloproteinase 1 (TIMP-1) was investigated by quantitative real-time PCR. The proliferation of HSCs was determined by MTS analysis. HBeAg transduction induced up-regulation of these fibrogenic genes and proliferation of HSCs. We found that HBeAg induced TGF-β secretion in HSCs, and the activation of HSCs was prevented by a neutralizing anti-TGF-β antibody. Depletion and addition of HBeAg protein in conditioned medium from HSC-T6 cells transduced with HBeAg indicated that HBeAg directly induced the activation and proliferation of rat primary HSCs. Taken together, HBeAg induces the activation and proliferation of HSCs, mainly mediated by TGF-β, and HBeAg protein purified from cell medium can directly activate HSCs

  19. Hepatitis B virus e antigen induces activation of rat hepatic stellate cells

    Energy Technology Data Exchange (ETDEWEB)

    Zan, Yanlu [Center for Molecular Virology, CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yuxia, E-mail: yzhang@wehi.edu.au [Center for Molecular Virology, CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101 (China); Tien, Po, E-mail: tienpo@sun.im.ac.cn [Center for Molecular Virology, CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101 (China)

    2013-06-07

    Highlights: •HBeAg expression in HSCs induced production of ECM protein and liver fibrotic markers. •The activation and proliferation of HSCs were mediated by TGF-β. •HBeAg protein purified from cell medium directly activated HSCs. -- Abstract: Chronic hepatitis B virus infection is a major cause of hepatic fibrosis, leading to liver cirrhosis and hepatocellular carcinoma. Hepatitis B virus e antigen (HBeAg) is an accessory protein of HBV, not required for viral replication but important for natural infection in vivo. Hepatic stellate cells (HSCs) are the major producers of excessive extracellular matrix during liver fibrogenesis. Therefore, we examined the influence of HBeAg on HSCs. The rat HSC line HSC-T6 was transfected with HBeAg plasmids, and expression of α-smooth muscle actin, collagen I, transforming growth factor-β1 (TGF-β), and tissue inhibitors of metalloproteinase 1 (TIMP-1) was investigated by quantitative real-time PCR. The proliferation of HSCs was determined by MTS analysis. HBeAg transduction induced up-regulation of these fibrogenic genes and proliferation of HSCs. We found that HBeAg induced TGF-β secretion in HSCs, and the activation of HSCs was prevented by a neutralizing anti-TGF-β antibody. Depletion and addition of HBeAg protein in conditioned medium from HSC-T6 cells transduced with HBeAg indicated that HBeAg directly induced the activation and proliferation of rat primary HSCs. Taken together, HBeAg induces the activation and proliferation of HSCs, mainly mediated by TGF-β, and HBeAg protein purified from cell medium can directly activate HSCs.

  20. 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)

  1. A single-strand specific lesion drives MMS-induced hyper-mutability at a double-strand break in yeast.

    Science.gov (United States)

    Yang, Yong; Gordenin, Dmitry A; Resnick, Michael A

    2010-08-05

    Localized hyper-mutability (LHM) can be important in evolution, immunity, and genetic diseases. We previously reported that single-strand DNA (ssDNA) can be an important source of damage-induced LHM in yeast. Here, we establish that the generation of LHM by methyl methanesulfonate (MMS) during repair of a chromosomal double-strand break (DSB) can result in over 0.2 mutations/kb, which is approximately 20,000-fold higher than the MMS-induced mutation density without a DSB. The MMS-induced mutations associated with DSB repair were primarily due to substitutions via translesion DNA synthesis at damaged cytosines, even though there are nearly 10 times more MMS-induced lesions at other bases. Based on this mutation bias, the promutagenic lesion dominating LHM is likely 3-methylcytosine, which is single-strand specific. Thus, the dramatic increase in mutagenesis at a DSB is concluded to result primarily from the generation of non-repairable lesions in ssDNA associated with DSB repair along with efficient induction of highly mutagenic ssDNA-specific lesions. These findings with MMS-induced LHM have broad biological implications for unrepaired damage generated in ssDNA and possibly ssRNA. Published by Elsevier B.V.

  2. On the mechanism of rapid postirradiation recovery of yeast

    International Nuclear Information System (INIS)

    Glazunov, A.V.; Kapul'tsevich, Yu.G.

    1983-01-01

    Rapid postirradiation recovery of diploid yeast Saccharomyces cerevisiae is equally effective both in water and in a liquid nutrition medium. In the haploid strains, rapid recovery occurs more readily in the log phase than in the stationary phase of growth. In the diploid strains, rapid recovery is more effective in the log phase than in the stationary phase. Rapid recovery of yeast does not require an additional protein synthesis. Damages induced by UV-light are not sub ected to rapid recovery

  3. Effects of Selenium Yeast on Blood Glucose and Antioxidant ...

    African Journals Online (AJOL)

    olayemitoyin

    Biomarkers in Cholesterol Fed Diet Induced Type 2 Diabetes. Mellitus in Wistar Rats. ... Keywords: Cholesterol diet; Diabetes Mellitus; Selenium yeast; SOD; CAT; GPx. ©Physiological ..... relationship with different diseases. Science Tot.

  4. HDV Seroprevalence in HBsAg Positive Patients

    International Nuclear Information System (INIS)

    Abbasi, A.; Bhutto, A. R.; Mahmood, K.; Butt, N.

    2014-01-01

    Objective: To find out the frequency of HDV seroprevalence and the demographic characteristics or HBsAg-HDV positive patients. Study Design: Cross-sectional analytical study. Place and Duration of Study: Jinnah Postgraduate Medical Centre and Civil Hospital, Medical Unit-III, Karachi, from March 2007 to April 2011. Methodology: Patients with positive HBsAg were included in the study. Those having co-infection with HCV or HIV, autoimmune hepatitis, alcoholic hepatitis, Wilson's disease and haemochromatosis were excluded. After detailed history and physical examination all the patients underwent laboratory workup including complete blood count, liver function test, viral profile (HAV, HCV, HIV and anti-HDV) and prothrombin time. While in selected patients, HBc (core) antibodies, ultrasound abdomen, serum iron profile, ANA and liver biopsy were also carried out whenever needed to establish a clinical stage of liver disease. Results: There were 374 patients with 266 (71.1%) males and 108 (28.9%) females with overall mean age of 31.64 +- 8.66 years. Overall frequency of anti-HDV antibodies positivity was found in 28.1% (n = 105) patients. HDV seropositivity was slightly more prevalent in males as compared to females (28.57% vs. 26.57%). HDV seropositivity frequency was significantly higher in patients who presented with acute hepatitis/hepatic failure as compared to other clinical diagnoses (p = 0.027) and in those sub-sets of patients who had raised ALT levels (p = 0.012). Conclusion: There was a high frequency of HDV seropositivity in the studied population particularly in males with acute hepatitis or hepatic failure, having raised ALT levels. The emphasis should be on preventive measures taken by other countries to reduce the prevalence of these treatment challenging infections. (author)

  5. [Detection of fps tumor antigen with mono-specific anti-fps serum in tumors induced by acute transforming ALV].

    Science.gov (United States)

    Wang, Yixin; Chen, Hao; Zhao, Peng; Li, Jianliang; Cui, Zhizhong

    2013-03-04

    To prepare anti-fps mono-specific serum, and detect the fps antigen in tumors induced by acute transforming avian leukosis/sarcoma virus containing v-fps oncogene. Two part of v-fps gene was amplified by RT-PCR using the Fu-J viral RNA as the template. Mono-specific serum was prepared by immuning Kunming white mouse with both two recombinant infusion proteins expressed by the prokaryotic expression system. Indirect immunofluorescent assay was used to detect fps antigen in tumor tissue suspension cells and CEF infected by sarcoma supernatant. Immunohistochemical method was used to detect fps antigen in tumor tissue. The mouse mono-specific serum was specific as it had no cross reaction with classical ALV-J strains. The result reveals that the tumor tissue suspension cells, the CEF infected by sarcoma supernatant, and the slice immunohistochemistry of the sarcoma showed positive results. The anti-fps mono-specific serum was prepared, and the detection method was established, which laid the foundation for the study of viral biological characteristics and mechanism of tumourgenesis of acute transforming avian leukosis/sarcoma virus containing v-fps oncogene.

  6. 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.

  7. Effect of Shock Waves Generated by Pulsed Electric Discharges in Water on Yeast Cells and Virus Particles

    Science.gov (United States)

    Girdyuk, A. E.; Gorshkov, A. N.; Egorov, V. V.; Kolikov, V. A.; Snetov, V. N.; Shneerson, G. A.

    2018-02-01

    The aim of this study is to determine the optimal parameters of the electric pulses and shock waves generated by them for the soft destruction of the virus and yeast envelopes with no changes in the structure of antigenic surface albumin and in the cell morphology in order to use them to produce antivirus vaccines and in biotechnology. The pulse electric discharges in water have been studied for different values of amplitude, pulse duration and the rate of the rise in the current. A mathematical model has been developed to estimate the optimal parameters of pulsed electric charges and shock waves for the complete destruction of the yeast cell envelopes and virus particles at a minimum of pulses.

  8. Inducible DNA-repair systems in yeast: competition for lesions.

    Science.gov (United States)

    Mitchel, R E; Morrison, D P

    1987-03-01

    DNA lesions may be recognized and repaired by more than one DNA-repair process. If two repair systems with different error frequencies have overlapping lesion specificity and one or both is inducible, the resulting variable competition for the lesions can change the biological consequences of these lesions. This concept was demonstrated by observing mutation in yeast cells (Saccharomyces cerevisiae) exposed to combinations of mutagens under conditions which influenced the induction of error-free recombinational repair or error-prone repair. Total mutation frequency was reduced in a manner proportional to the dose of 60Co-gamma- or 254 nm UV radiation delivered prior to or subsequent to an MNNG exposure. Suppression was greater per unit radiation dose in cells gamma-irradiated in O2 as compared to N2. A rad3 (excision-repair) mutant gave results similar to wild-type but mutation in a rad52 (rec-) mutant exposed to MNNG was not suppressed by radiation. Protein-synthesis inhibition with heat shock or cycloheximide indicated that it was the mutation due to MNNG and not that due to radiation which had changed. These results indicate that MNNG lesions are recognized by both the recombinational repair system and the inducible error-prone system, but that gamma-radiation induction of error-free recombinational repair resulted in increased competition for the lesions, thereby reducing mutation. Similarly, gamma-radiation exposure resulted in a radiation dose-dependent reduction in mutation due to MNU, EMS, ENU and 8-MOP + UVA, but no reduction in mutation due to MMS. These results suggest that the number of mutational MMS lesions recognizable by the recombinational repair system must be very small relative to those produced by the other agents. MNNG induction of the inducible error-prone systems however, did not alter mutation frequencies due to ENU or MMS exposure but, in contrast to radiation, increased the mutagenic effectiveness of EMS. These experiments demonstrate

  9. Apoptosis-like yeast cell death in response to DNA damage and replication defects

    Energy Technology Data Exchange (ETDEWEB)

    Burhans, William C.; Weinberger, Martin; Marchetti, Maria A.; Ramachandran, Lakshmi; D' Urso, Gennaro; Huberman, Joel A

    2003-11-27

    In budding (Saccharomyces cerevisiae) and fission (Schizosaccharomyces pombe) yeast and other unicellular organisms, DNA damage and other stimuli can induce cell death resembling apoptosis in metazoans, including the activation of a recently discovered caspase-like molecule in budding yeast. Induction of apoptotic-like cell death in yeasts requires homologues of cell cycle checkpoint proteins that are often required for apoptosis in metazoan cells. Here, we summarize these findings and our unpublished results which show that an important component of metazoan apoptosis recently detected in budding yeast - reactive oxygen species (ROS) - can also be detected in fission yeast undergoing an apoptotic-like cell death. ROS were detected in fission and budding yeast cells bearing conditional mutations in genes encoding DNA replication initiation proteins and in fission yeast cells with mutations that deregulate cyclin-dependent kinases (CDKs). These mutations may cause DNA damage by permitting entry of cells into S phase with a reduced number of replication forks and/or passage through mitosis with incompletely replicated chromosomes. This may be relevant to the frequent requirement for elevated CDK activity in mammalian apoptosis, and to the recent discovery that the initiation protein Cdc6 is destroyed during apoptosis in mammals and in budding yeast cells exposed to lethal levels of DNA damage. Our data indicate that connections between apoptosis-like cell death and DNA replication or CDK activity are complex. Some apoptosis-like pathways require checkpoint proteins, others are inhibited by them, and others are independent of them. This complexity resembles that of apoptotic pathways in mammalian cells, which are frequently deregulated in cancer. The greater genetic tractability of yeasts should help to delineate these complex pathways and their relationships to cancer and to the effects of apoptosis-inducing drugs that inhibit DNA replication.

  10. Apoptosis-like yeast cell death in response to DNA damage and replication defects

    International Nuclear Information System (INIS)

    Burhans, William C.; Weinberger, Martin; Marchetti, Maria A.; Ramachandran, Lakshmi; D'Urso, Gennaro; Huberman, Joel A.

    2003-01-01

    In budding (Saccharomyces cerevisiae) and fission (Schizosaccharomyces pombe) yeast and other unicellular organisms, DNA damage and other stimuli can induce cell death resembling apoptosis in metazoans, including the activation of a recently discovered caspase-like molecule in budding yeast. Induction of apoptotic-like cell death in yeasts requires homologues of cell cycle checkpoint proteins that are often required for apoptosis in metazoan cells. Here, we summarize these findings and our unpublished results which show that an important component of metazoan apoptosis recently detected in budding yeast - reactive oxygen species (ROS) - can also be detected in fission yeast undergoing an apoptotic-like cell death. ROS were detected in fission and budding yeast cells bearing conditional mutations in genes encoding DNA replication initiation proteins and in fission yeast cells with mutations that deregulate cyclin-dependent kinases (CDKs). These mutations may cause DNA damage by permitting entry of cells into S phase with a reduced number of replication forks and/or passage through mitosis with incompletely replicated chromosomes. This may be relevant to the frequent requirement for elevated CDK activity in mammalian apoptosis, and to the recent discovery that the initiation protein Cdc6 is destroyed during apoptosis in mammals and in budding yeast cells exposed to lethal levels of DNA damage. Our data indicate that connections between apoptosis-like cell death and DNA replication or CDK activity are complex. Some apoptosis-like pathways require checkpoint proteins, others are inhibited by them, and others are independent of them. This complexity resembles that of apoptotic pathways in mammalian cells, which are frequently deregulated in cancer. The greater genetic tractability of yeasts should help to delineate these complex pathways and their relationships to cancer and to the effects of apoptosis-inducing drugs that inhibit DNA replication

  11. The role of mitochondria in yeast programmed cell death

    International Nuclear Information System (INIS)

    Guaragnella, Nicoletta; Ždralević, Maša; Antonacci, Lucia; Passarella, Salvatore; Marra, Ersilia; Giannattasio, Sergio

    2012-01-01

    Mammalian apoptosis and yeast programmed cell death (PCD) share a variety of features including reactive oxygen species production, protease activity and a major role played by mitochondria. In view of this, and of the distinctive characteristics differentiating yeast and multicellular organism PCD, the mitochondrial contribution to cell death in the genetically tractable yeast Saccharomyces cerevisiae has been intensively investigated. In this mini-review we report whether and how yeast mitochondrial function and proteins belonging to oxidative phosphorylation, protein trafficking into and out of mitochondria, and mitochondrial dynamics, play a role in PCD. Since in PCD many processes take place over time, emphasis will be placed on an experimental model based on acetic acid-induced PCD (AA-PCD) which has the unique feature of having been investigated as a function of time. As will be described there are at least two AA-PCD pathways each with a multifaceted role played by mitochondrial components, in particular by cytochrome c.

  12. Immunization with the recombinant antigen Ss-IR induces protective immunity to infection with Strongyloides stercoralis in mice.

    Science.gov (United States)

    Abraham, David; Hess, Jessica A; Mejia, Rojelio; Nolan, Thomas J; Lok, James B; Lustigman, Sara; Nutman, Thomas B

    2011-10-19

    Human intestinal infections with the nematode Strongyloides stercoralis remain a significant problem worldwide and a vaccine would be a useful addition to the tools available to prevent and control this infection. The goal of this study was to test single antigens for their efficacy in a vaccine against S. stercoralis larvae in mice. Alum was used as the adjuvant in these studies and antigens selected for analysis were either recognized by protective human IgG (Ss-TMY-1, Ss-EAT-6, and Ss-LEC-5) or were known to be highly immunogenic in humans (Ss-NIE-1 and Ss-IR). Only mice immunized with the Ss-IR antigen demonstrated a significant decrease of approximately 80% in the survival of larval parasites in the challenge infection. Antibodies, recovered from mice with protective immunity to S. stercoralis after immunization with Ss-IR, were used to locate the antigen in the larvae. Confocal microscopy revealed that IgG from mice immunized with Ss-IR bound to the surface of the parasites and observations by electron microscopy indicated that IgG bound to granules in the glandular esophagus. Serum collected from mice immunized with Ss-IR passively transferred immunity to naïve mice. These studies demonstrate that Ss-IR, in combination with alum, induces high levels of protective immunity through an antibody dependent mechanism and may therefore be suitable for further development as a vaccine against human strongyloidiasis. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Immunomodulatory activity of andrographolide on macrophage activation and specific antibody response

    Science.gov (United States)

    Wang, Wei; Wang, Jing; Dong, Sheng-fu; Liu, Chun-hong; Italiani, Paola; Sun, Shu-hui; Xu, Jing; Boraschi, Diana; Ma, Shi-ping; Qu, Di

    2010-01-01

    Aim: To investigate the immunomodulatory effects of andrographolide on both innate and adaptive immune responses. Methods: Andrographolide (10 μg/mL in vitro or 1 mg/kg in vivo) was used to modulate LPS-induced classical activated (M1) or IL-4-induced alternative activated (M2) macrophages in vitro and humor immune response to HBsAg in vivo. Cytokine gene expression profile (M1 vs M2) was measured by real-time PCR, IL-12/IL-10 level was detected by ELISA, and surface antigen expression was evaluated by flow cytometry, whereas phosphorylation level of ERK 1/2 and AKT was determined by Western blot. The level of anti-HBs antibodies in HBsAg immunized mice was detected by ELISA, and the number of HBsAg specific IL-4-producing splenocyte was enumerated by ELISPOT. Results: Andrographolide treatment in vitro attenuated either LPS or IL-4 induced macrophage activation, inhibited both M1 and M2 cytokines expression and decreased IL-12/IL-10 ratio (the ratio of M1/M2 polarization). Andrographolide down-regulated the expression of mannose receptor (CD206) in IL-4 induced macrophages and major histocompability complex/costimulatory molecules (MHC I, CD40, CD80, CD86) in LPS-induced macrophages. Correspondingly, anti-HBs antibody production and the number of IL-4-producing splenocytes were reduced by in vivo administration of andrographolide. Reduced phosphorylation levels of ERK1/2 and AKT were observed in macrophages treated with andrographolide. Conclusion: Andrographolide can modulate the innate and adaptive immune responses by regulating macrophage phenotypic polarization and Ag-specific antibody production. MAPK and PI3K signaling pathways may participate in the mechanisms of andrographolide regulating macrophage activation and polarization. PMID:20139902

  14. Polyglutamine toxicity in yeast induces metabolic alterations and mitochondrial defects

    KAUST Repository

    Papsdorf, Katharina; Kaiser, Christoph J. O.; Drazic, Adrian; Grö tzinger, Stefan W.; Haeß ner, Carmen; Eisenreich, Wolfgang; Richter, Klaus

    2015-01-01

    formation. Indeed, we find that in vivo iron concentrations are misbalanced and observe a reduction in the activity of the prominent Fe-S cluster containing protein aconitase. Like in other yeast strains with impaired mitochondria, non-fermentative growth

  15. Transformation of tobacco plant (Nicotiana tabacum L. with the recombinant hepatitis B virus genes 35SHBsAg and 35SHBsAgER

    Directory of Open Access Journals (Sweden)

    Juliana Martins Ribeiro

    2010-03-01

    Full Text Available The recombinant surface antigen of hepatitis B virus (HBsAg, purified from transgenic plants, proved to be efficient when utilized for raising anti-HB antibodies for the prevention of hepatitis B. Because of the important role of the HBsAg antigen in hepatitis B prevention, the coding sequence of HBsAg antigen, with or without the addition of the carboxi-terminus sequence for protein retention in the endoplasmatic reticulum, was linked to cauliflower mosaic virus 35S promoter, tobacco mosaic virus leader sequence Ω, and the transcription terminator sequence. The aim of this work was to clone the chimeric gene 35SHBsAgER in the plant expression vector pGPTV/Kan/Asc. The resulting plasmid, called pG35SHBsAgER, and another plasmid produced previously in our laboratory called pG35SHBsAg, were transferred to Agrobacterium tumefaciens, and tobacco leaves, of the SR1 cultivar were used as explants for genetic transformation. Twenty-one fully regenerated plants were obtained (10 for the pG35SHBsAg construction and 11 for the pG35SHBsAgER construction. The genomic DNA of all plants was analyzed by PCR, and the presence of the transgene was confirmed in all plants.

  16. Antigen-induced pleural eosinophilia is suppressed in diabetic rats: role of corticosteroid hormones

    Directory of Open Access Journals (Sweden)

    Bruno L Diaz

    1997-12-01

    Full Text Available Previous studies have evidenced for the existence of interactive regulatory mechanisms between insulin and steroid hormones in different systems. In this study, we have investigated whether endogenous corticosteroids could be implicated in the hyporeactivity to antigen challenge observed in sensitized diabetic rats. Alloxinated rats showed a long-lasting increase in the blood glucose levels and a reduction in the number of pleural mast cells at 48 and 72 hr, but not at 24 hr after alloxan administration. In parallel, they also showed a significant elevation in the plasma levels of corticosterone together with an increase in the adrenal/body weight ratio. Antigen-evoked eosinophil accumulation appeared significantly reduced in rats pretreated with dexamethasone as well as in those rendered diabetic 72 hr after alloxan. In the same way, naive animals treated with dexamethasone also responded with a significant decrease in the number of pleural mast cells. Interestingly, when sensitized diabetic rats were pretreated with the steroid antagonist RU 38486 a reversion of the reduction in the allergen-induced eosinophil accumulation was noted. We conclude that the down-regulation of the allergic inflammatory response in diabetic rats is close-related to reduction in mast cell numbers and over expression of endogenous corticosteroids.

  17. Recombinant Lactobacillus plantarum induces immune responses to cancer testis antigen NY-ESO-1 and maturation of dendritic cells

    Science.gov (United States)

    Mobergslien, Anne; Vasovic, Vlada; Mathiesen, Geir; Fredriksen, Lasse; Westby, Phuong; Eijsink, Vincent GH; Peng, Qian; Sioud, Mouldy

    2015-01-01

    Given their safe use in humans and inherent adjuvanticity, Lactic Acid Bacteria may offer several advantages over other mucosal delivery strategies for cancer vaccines. The objective of this study is to evaluate the immune responses in mice after oral immunization with Lactobacillus (L) plantarum WCFS1 expressing a cell-wall anchored tumor antigen NY-ESO-1. And to investigate the immunostimulatory potency of this new candidate vaccine on human dendritic cells (DCs). L. plantarum displaying NY-ESO-1 induced NY-ESO-1 specific antibodies and T-cell responses in mice. By contrast, L. plantarum displaying conserved proteins such as heat shock protein-27 and galectin-1, did not induce immunity, suggesting that immune tolerance to self-proteins cannot be broken by oral administration of L. plantarum. With respect to immunomodulation, immature DCs incubated with wild type or L. plantarum-NY-ESO-1 upregulated the expression of co-stimulatory molecules and secreted a large amount of interleukin (IL)-12, TNF-α, but not IL-4. Moreover, they upregulated the expression of immunosuppressive factors such as IL-10 and indoleamine 2,3-dioxygenase. Although L. plantarum-matured DCs expressed inhibitory molecules, they stimulated allogeneic T cells in-vitro. Collectively, the data indicate that L. plantarum-NY-ESO-1 can evoke antigen-specific immunity upon oral administration and induce DC maturation, raising the potential of its use in cancer immunotherapies. PMID:26185907

  18. Method for using a yeast alpha-amylase promoter

    Science.gov (United States)

    Gao, Johnway; Skeen, Rodney S.; Hooker, Brian S.; Anderson, Daniel B.

    2003-04-22

    The present invention provides the promoter clone discovery of an alpha-amylase gene of a starch utilizing yeast strain Schwanniomyces castellii. The isolated alpha-amylase promoter is an inducible promoter, which can regulate strong gene expression in starch culture medium.

  19. 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.

  20. A microculture system for the measurement of antigen-induced murine lymphocyte proliferation: advantages of 5% horse serum and 5 X 10(-5) M mercaptoethanol.

    Science.gov (United States)

    Brummer, E; Vris, T W; Lawrence, H S

    1977-01-01

    Short term microculture systems which measure murine lymphocyte proliferative responses to mitogens are well established. We demonstrate here that these microculture methods are not suitable for antigen-induced responses because of the high levels of murine lymphocyte proliferation in control cultures associated with the use of fetal calf serum or human serum. We also show that this problem can be eliminated with the use of a combination of 5% horse serum and 5 X 10(-5) M mercaptoethanol. We describe an antigen-induced murine lymphocyte proliferation microculture system in which good stimulation indices are achieved and the lymphocyte proliferation in control cultures remain at a low level throughout the 7 day culture period.

  1. Denatured states of yeast cytochrome c induced by heat and guanidinium chloride are structurally and thermodynamically different.

    Science.gov (United States)

    Zaidi, Sobia; Haque, Md Anzarul; Ubaid-Ullah, Shah; Prakash, Amresh; Hassan, Md Imtaiyaz; Islam, Asimul; Batra, Janendra K; Ahmad, Faizan

    2017-05-01

    A sequence alignment of mammalian cytochromes c with yeast iso-1-cytochrome c (y-cyt-c) shows that the yeast protein contains five extra N-terminal residues. We have been interested in understanding the question: What is the role of these five extra N-terminal residues in folding and stability of the protein? To answer this question we have prepared five deletants of y-cyt-c by sequentially removing these extra residues. During our studies on the wild type (WT) protein and its deletants, we observed that the amount of secondary structure in the guanidinium chloride (GdmCl)-induced denatured (D) state of each protein is different from that of the heat-induced denatured (H) state. This finding is confirmed by the observation of an additional cooperative transition curve of optical properties between H and D states on the addition of different concentrations of GdmCl to the already heat denatured WT y-cyt-c and its deletants at pH 6.0 and 68°C. For each protein, analysis of transition curves representing processes, native (N) state ↔ D state, N state ↔ H state, and H state ↔ D state, was done to obtain Gibbs free energy changes associated with all the three processes. This analysis showed that, for each protein, thermodynamic cycle accommodates Gibbs free energies associated with transitions between N and D states, N and H states, and H and D states, the characteristics required for a thermodynamic function. All these experimental observations have been supported by our molecular dynamics simulation studies.

  2. Structural differences between yeast and mammalian microtubules revealed by cryo-EM

    Energy Technology Data Exchange (ETDEWEB)

    Howes, Stuart C. [Univ. of California, Berkeley, CA (United States). Biophysics Graduate Group; Geyer, Elisabeth A. [Univ. of Texas Southwestern Medical Center, Dallas, TX (United States). Dept. of Biophysics; Univ. of Texas Southwestern Medical Center, Dallas, TX (United States). Dept. of Biochemistry; LaFrance, Benjamin [Univ. of California, Berkeley, CA (United States). Molecular and Cell Biology Graduate Program; Zhang, Rui [Univ. of California, Berkeley, CA (United States). Howard Hughes Medical Inst.; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging Division; Kellogg, Elizabeth H. [Univ. of California, Berkeley, CA (United States). Howard Hughes Medical Inst.; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging Division; Westermann, Stefan [Univ. of Duisburg-Essen, Essen (Germany). Dept. of Molecular Genetics, Center for Medical Biotechnology; Rice, Luke M. [Univ. of Texas Southwestern Medical Center, Dallas, TX (United States). Dept. of Biophysics; Univ. of Texas Southwestern Medical Center, Dallas, TX (United States). Dept. of Biochemistry; Nogales, Eva [Univ. of California, Berkeley, CA (United States). Howard Hughes Medical Inst.; Univ. of California, Berkeley, CA (United States). Dept. of Molecular Biology and California Inst. for Quantitative Biosciences; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging Division

    2017-06-26

    Microtubules are polymers of αβ-tubulin heterodimers essential for all eukaryotes. Despite sequence conservation, there are significant structural differences between microtubules assembled in vitro from mammalian or budding yeast tubulin. Yeast MTs were not observed to undergo compaction at the interdimer interface as seen for mammalian microtubules upon GTP hydrolysis. Lack of compaction might reflect slower GTP hydrolysis or a different degree of allosteric coupling in the lattice. The microtubule plus end–tracking protein Bim1 binds yeast microtubules both between αβ-tubulin heterodimers, as seen for other organisms, and within tubulin dimers, but binds mammalian tubulin only at interdimer contacts. At the concentrations used in cryo-electron microscopy, Bim1 causes the compaction of yeast microtubules and induces their rapid disassembly. In conclusion, our studies demonstrate structural differences between yeast and mammalian microtubules that likely underlie their differing polymerization dynamics. These differences may reflect adaptations to the demands of different cell size or range of physiological growth temperatures.

  3. Fusion protein of tapasin and hepatitis B core antigen 18‑27 enhances T helper cell type 1/2 cytokine ratio and antiviral immunity by inhibiting suppressors of cytokine signaling family members 1/3 in hepatitis B virus transgenic mice.

    Science.gov (United States)

    Tang, Yuyan; Chen, Xiaohua; Zhang, Yi; Tang, Zhenghao; Zhuo, Meng; Li, Dan; Wang, Peng; Zang, Guoqing; Yu, Yongsheng

    2014-04-01

    Persistent hepatitis B virus (HBV) infection is characterized by a weak adaptive immune response, which is considered to be due to an imbalance of T helper cell types 1 and 2 (Th1/Th2). Suppressors of cytokine signaling (SOCS) family members, particularly SOCS1 and SOCS3, have been demonstrated to be important in the regulation of T cell differentiation. Previous studies by our group showed that the expressed and purified fusion protein of cytoplasmic transduction peptide (CTP) and HBV core antigen 18‑27 (HBcAg18‑27)‑tapasin was able to enter the cytoplasm of bone marrow‑derived dendritic cells (BMDCs), promoting the maturation of BMDCs and efficiently enhancing T cell immune responses in vitro. In the present study, HBcAg‑specific immune responses induced by CTP‑HBcAg18‑27‑tapasin in HBV were assessed in transgenic mice, and SOCS1 and SOCS3 were identified as negative regulators of this response. The Th1/Th2 cytokine ratio was analyzed by ELISA. The expression of T cell‑specific T‑box transcription factor (T‑bet) and GATA‑binding protein 3 (GATA‑3), SOCS1 and SOCS3 were detected by real‑time quantitative polymerase chain reaction and western blot analysis. The results demonstrated that CTP‑HBcAg18‑27‑tapasin significantly increased the Th1/Th2 cytokine ratio in HBV transgenic mice. CTP‑HBcAg18‑27‑tapasin immunization more efficiently suppressed the expression of serum hepatitis B surface antigen (HBsAg), HBV DNA as well as liver HBsAg and HBcAg in HBV transgenic mice. Furthermore, CTP‑HBcAg18‑27‑tapasin promotes T‑bet but reduces GATA‑3 expression. In addition, the expression of SOCS1 and SOCS3 was significantly downregulated in the CTP‑HBcAg18‑27‑tapasin group compared with the control groups. In conclusion, the present study demonstrated that CTP‑HBcAg18‑27‑tapasin enhanced the Th1/Th2 cytokine ratio and antiviral immunity by suppressing SOCS1/3 in HBV transgenic mice.

  4. Detection of NP, N3 and N7 antibodies to avian influenza virus by indirect ELISA using yeast-expressed antigens

    Directory of Open Access Journals (Sweden)

    Ammayappan Arun

    2009-10-01

    Full Text Available Abstract Background Avian influenza viruses, belonging to the family Orthomyxoviridae, possess distinct combinations of hemagglutinin (H and the neuraminidase (N surface glycoproteins. Typing of both H and N antigens is essential for the epidemiological and surveillance studies. Therefore, it is important to find a rapid, sensitive, and specific method for their assay, and ELISA can be useful for this purpose, by using recombinant proteins. Results The nucleoprotein (NP and truncated neuraminidase subtype 3 and 7 of avian influenza virus (AIV were expressed in Saccharomyces cerevisiae and used to develop an indirect enzyme-linked immunosorbent assay for antibody detection. The developed assays were evaluated with a panel of 64 chicken serum samples. The performance of NP-ELISA was compared with the commercially available ProFlok® AIV ELISA kit. The results showed comparable agreement and sensitivity between the two tests, indicating that NP-ELISA assay can be used for screening the influenza type A antibody in AIV infected birds. The N3 and N7- ELISAs also reacted specifically to their type specific sera and did not exhibit any cross-reaction with heterologous neuraminidase subtype specific sera. Conclusion The study demonstrates the expression of the NP, N3, and N7 proteins of AIV in yeast (S. cerevisiae and their application in developing an indirect ELISA for detecting NP, N3 and N7 antibodies from AIV-infected chicken sera. The described indirect ELISAs are rapid, sensitive, specific and can be used as promising tests during serological surveillance.

  5. Genome-wide identification of pheromone-targeted transcrption in fission yeast

    DEFF Research Database (Denmark)

    Xue-Franzen, Y.; Kjærulff, S.; Holmberg, C.

    2006-01-01

    Background Fission yeast cells undergo sexual differentiation in response to nitrogen starvation. In this process haploid M and P cells first mate to form diploid zygotes, which then enter meiosis and sporulate. Prior to mating, M and P cells communicate with diffusible mating pheromones that act......Background Fission yeast cells undergo sexual differentiation in response to nitrogen starvation. In this process haploid M and P cells first mate to form diploid zygotes, which then enter meiosis and sporulate. Prior to mating, M and P cells communicate with diffusible mating pheromones...... transcription factor is responsible for the majority of pheromone-induced transcription. Finally, most cell-type specific genes now appear to be identified in fission yeast....

  6. Non-homologous end joining dependency of {gamma}-irradiation-induced adaptive frameshift mutation formation in cell cycle-arrested yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Heidenreich, Erich [Institute of Cancer Research, Division of Molecular Genetics, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna (Austria)]. E-mail: erich.heidenreich@meduniwien.ac.at; Eisler, Herfried [Institute of Cancer Research, Division of Molecular Genetics, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna (Austria)

    2004-11-22

    There is a strong selective pressure favoring adaptive mutations which relieve proliferation-limiting adverse living conditions. Due to their importance for evolution and pathogenesis, we are interested in the mechanisms responsible for the formation of such adaptive, gain-of-fitness mutations in stationary-phase cells. During previous studies on the occurrence of spontaneous reversions of an auxotrophy-causing frameshift allele in the yeast Saccharomyces cerevisiae, we noticed that about 50% of the adaptive reversions depended on a functional non-homologous end joining (NHEJ) pathway of DNA double-strand break (DSB) repair. Here, we show that the occasional NHEJ component Pol4, which is the yeast ortholog of mammalian DNA polymerase lambda, is not required for adaptive mutagenesis. An artificially imposed excess of DSBs by {gamma}-irradiation resulted in a dramatic increase in the incidence of adaptive, cell cycle arrest-releasing frameshift reversions. By the use of DNA ligase IV-deficient strains we detected that the majority of the {gamma}-induced adaptive mutations were also dependent on a functional NHEJ pathway. This suggests that the same mutagenic NHEJ mechanism acts on spontaneously arising as well as on ionizing radiation-induced DSBs. Inaccuracy of the NHEJ repair pathway may extensively contribute to the incidence of frameshift mutations in resting (non-dividing) eukaryotic cells, and thus act as a driving force in tumor development.

  7. Non-homologous end joining dependency of γ-irradiation-induced adaptive frameshift mutation formation in cell cycle-arrested yeast cells

    International Nuclear Information System (INIS)

    Heidenreich, Erich; Eisler, Herfried

    2004-01-01

    There is a strong selective pressure favoring adaptive mutations which relieve proliferation-limiting adverse living conditions. Due to their importance for evolution and pathogenesis, we are interested in the mechanisms responsible for the formation of such adaptive, gain-of-fitness mutations in stationary-phase cells. During previous studies on the occurrence of spontaneous reversions of an auxotrophy-causing frameshift allele in the yeast Saccharomyces cerevisiae, we noticed that about 50% of the adaptive reversions depended on a functional non-homologous end joining (NHEJ) pathway of DNA double-strand break (DSB) repair. Here, we show that the occasional NHEJ component Pol4, which is the yeast ortholog of mammalian DNA polymerase lambda, is not required for adaptive mutagenesis. An artificially imposed excess of DSBs by γ-irradiation resulted in a dramatic increase in the incidence of adaptive, cell cycle arrest-releasing frameshift reversions. By the use of DNA ligase IV-deficient strains we detected that the majority of the γ-induced adaptive mutations were also dependent on a functional NHEJ pathway. This suggests that the same mutagenic NHEJ mechanism acts on spontaneously arising as well as on ionizing radiation-induced DSBs. Inaccuracy of the NHEJ repair pathway may extensively contribute to the incidence of frameshift mutations in resting (non-dividing) eukaryotic cells, and thus act as a driving force in tumor development

  8. Radiation stimulation of yeast crops for increasing output of alcohol and baker yeasts

    International Nuclear Information System (INIS)

    Vlad, E.; Marsheu, P.

    1974-01-01

    The purpose of this study was to stimulate by gamma radiation the existing commercial types of yeast so as to obtain yeasts that would better reflect the substrate and have improved reproductive capacity. The experiments were conducted under ordinary conditions using commercial yeasts received from one factory producing alcohol and bakery yeasts and isolated as pure cultures. Irradiating yeast cultures with small doses (up to 10 krad) was found to stimulate the reproduction and fermenting activity of yeast cells as manifested in increased accumulation of yeast biomass and greater yield of ethyl alcohol. (E.T.)

  9. Augmentation of antigen-specific immune responses using DNA-fusogenic liposome vaccine

    International Nuclear Information System (INIS)

    Yoshikawa, Tomoaki; Imazu, Susumu; Gao Jianqing; Hayashi, Kazuyuki; Tsuda, Yasuhiro; Shimokawa, Mariko; Sugita, Toshiki; Niwa, Takako; Oda, Atushi; Akashi, Mitsuru; Tsutsumi, Yasuo; Mayumi, Tadanori; Nakagawa, Shinsaku

    2004-01-01

    In an attempt to enhance the immunological efficacy of genetic immunization, we investigated a new biological means for delivering antigen gene directly to the cytoplasm via membrane fusion. In this context, we investigated fusogenic liposome (FL) encapsulating DNA as a possible genetic immunization vehicle. RT-PCR analysis indicated that a FL could introduce and express encapsulating OVA gene efficiently and rapidly in vitro. Consistent with this observation, an in vitro assay showed that FL-mediated antigen-gene delivery can induce potent presentation of antigen via the MHC class I-dependent pathway. Accordingly, immunization with FL containing the OVA-gene induced potent OVA-specific Th1 and Th2 cytokine production. Additionally, OVA-specific CTL responses and antibody production were also observed in systemic compartments including the spleen, upon immunization with the OVA-gene encapsulating FL. These findings suggest that FL is an effective genetic immunization carrier system for the stimulation of antigen-specific immune responses against its encoding antigen

  10. Global analysis of the yeast lipidome by quantitative shotgun mass spectrometry

    DEFF Research Database (Denmark)

    Ejsing, Christer S.; Sampaio, Julio L; Surendranath, Vineeth

    2009-01-01

    95% coverage of the yeast lipidome achieved with 125-fold improvement in sensitivity compared with previous approaches. Comparative lipidomics demonstrated that growth temperature and defects in lipid biosynthesis induce ripple effects throughout the molecular composition of the yeast lipidome....... This work serves as a resource for molecular characterization of eukaryotic lipidomes, and establishes shotgun lipidomics as a powerful platform for complementing biochemical studies and other systems-level approaches....

  11. Goodbye warts, hello vitiligo: Candida antigen-induced depigmentation.

    Science.gov (United States)

    Wilmer, Erin N; Burkhart, Craig N; Morrell, Dean S

    2013-01-01

    Depigmentation after the use of topical immune modulators is a rare but reported event. Herein we present what is to our knowledge the first case of vitiligo at a site of Candida antigen injection. © 2012 Wiley Periodicals, Inc.

  12. Studying p53 family proteins in yeast: Induction of autophagic cell death and modulation by interactors and small molecules

    Energy Technology Data Exchange (ETDEWEB)

    Leão, Mariana; Gomes, Sara; Bessa, Cláudia; Soares, Joana; Raimundo, Liliana [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal); Monti, Paola; Fronza, Gilberto [Mutagenesis Unit, Istituto di Ricerca e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST-Istituto Nazionale per la Ricerca sul Cancro, 16132 Genoa (Italy); Pereira, Clara [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal); Saraiva, Lucília, E-mail: lucilia.saraiva@ff.up.pt [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal)

    2015-01-01

    In this work, the yeast Saccharomyces cerevisiae was used to individually study human p53, p63 (full length and truncated forms) and p73. Using this cell system, the effect of these proteins on cell proliferation and death, and the influence of MDM2 and MDMX on their activities were analyzed. When expressed in yeast, wild-type p53, TAp63, ΔNp63 and TAp73 induced growth inhibition associated with S-phase cell cycle arrest. This growth inhibition was accompanied by reactive oxygen species production and autophagic cell death. Furthermore, they stimulated rapamycin-induced autophagy. On the contrary, none of the tested p53 family members induced apoptosis either per se or after apoptotic stimuli. As previously reported for p53, also TAp63, ΔNp63 and TAp73 increased actin expression levels and its depolarization, suggesting that ACT1 is also a p63 and p73 putative yeast target gene. Additionally, MDM2 and MDMX inhibited the activity of all tested p53 family members in yeast, although the effect was weaker on TAp63. Moreover, Nutlin-3a and SJ-172550 were identified as potential inhibitors of the p73 interaction with MDM2 and MDMX, respectively. Altogether, the yeast-based assays herein developed can be envisaged as a simplified cell system to study the involvement of p53 family members in autophagy, the modulation of their activities by specific interactors (MDM2 and MDMX), and the potential of new small molecules to modulate these interactions. - Highlights: • p53, p63 and p73 are individually studied in the yeast S. cerevisiae. • p53 family members induce ROS production, cell cycle arrest and autophagy in yeast. • p53 family members increase actin depolarization and expression levels in yeast. • MDM2 and MDMX inhibit the activity of p53 family members in yeast. • Yeast can be a useful tool to study the biology and drugability of p53, p63 and p73.

  13. Studying p53 family proteins in yeast: Induction of autophagic cell death and modulation by interactors and small molecules

    International Nuclear Information System (INIS)

    Leão, Mariana; Gomes, Sara; Bessa, Cláudia; Soares, Joana; Raimundo, Liliana; Monti, Paola; Fronza, Gilberto; Pereira, Clara; Saraiva, Lucília

    2015-01-01

    In this work, the yeast Saccharomyces cerevisiae was used to individually study human p53, p63 (full length and truncated forms) and p73. Using this cell system, the effect of these proteins on cell proliferation and death, and the influence of MDM2 and MDMX on their activities were analyzed. When expressed in yeast, wild-type p53, TAp63, ΔNp63 and TAp73 induced growth inhibition associated with S-phase cell cycle arrest. This growth inhibition was accompanied by reactive oxygen species production and autophagic cell death. Furthermore, they stimulated rapamycin-induced autophagy. On the contrary, none of the tested p53 family members induced apoptosis either per se or after apoptotic stimuli. As previously reported for p53, also TAp63, ΔNp63 and TAp73 increased actin expression levels and its depolarization, suggesting that ACT1 is also a p63 and p73 putative yeast target gene. Additionally, MDM2 and MDMX inhibited the activity of all tested p53 family members in yeast, although the effect was weaker on TAp63. Moreover, Nutlin-3a and SJ-172550 were identified as potential inhibitors of the p73 interaction with MDM2 and MDMX, respectively. Altogether, the yeast-based assays herein developed can be envisaged as a simplified cell system to study the involvement of p53 family members in autophagy, the modulation of their activities by specific interactors (MDM2 and MDMX), and the potential of new small molecules to modulate these interactions. - Highlights: • p53, p63 and p73 are individually studied in the yeast S. cerevisiae. • p53 family members induce ROS production, cell cycle arrest and autophagy in yeast. • p53 family members increase actin depolarization and expression levels in yeast. • MDM2 and MDMX inhibit the activity of p53 family members in yeast. • Yeast can be a useful tool to study the biology and drugability of p53, p63 and p73

  14. Specific proliferative response of human lymphocytes to purified soluble antigens from Plasmodium falciparum in vitro cultures and to antigens from malaria patients' sera

    DEFF Research Database (Denmark)

    Bygbjerg, I C; Jepsen, S; Theander, T G

    1985-01-01

    Antigens of Plasmodium falciparum, in supernatants of in vitro cultures of the parasite were affinity purified on columns prepared with the IgG fraction of the serum of an immune individual. The purified antigens induced proliferation of lymphocytes from persons who had recently had malaria....... The responses were strongest with lymphocytes from individuals infected with falciparum and ovale malaria; vivax malaria infections induced a lower level of response and lymphocytes of unsensitized individuals were little affected. Lymphocytes from unsensitized individuals did not respond to the affinity...

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

    Science.gov (United States)

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

    2016-02-01

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

  16. Rapid customised operon assembly by yeast recombinational cloning.

    Science.gov (United States)

    Liu, Michael A; Kenyon, Johanna J; Lee, Jason; Reeves, Peter R

    2017-06-01

    We have developed a system called the Operon Assembly Protocol (OAP), which takes advantage of the homologous recombination DNA repair pathway in Saccharomyces cerevisiae to assemble full-length operons from a series of overlapping PCR products into a specially engineered yeast-Escherichia coli shuttle vector. This flexible, streamlined system can be used to assemble several operon clones simultaneously, and each clone can be expressed in the same E. coli tester strain to facilitate direct functional comparisons. We demonstrated the utility of the OAP by assembling and expressing a series of E. coli O1A O-antigen gene cluster clones containing various gene deletions or replacements. We then used these constructs to assess the substrate preferences of several Wzx flippases, which are responsible for translocation of oligosaccharide repeat units (O units) across the inner membrane during O-antigen biosynthesis. We were able to identify several O unit structural features that appear to be important determinants of Wzx substrate preference. The OAP system should be broadly applicable for the genetic manipulation of any bacterial operon and can be modified for use in other host species. It could also have potential uses in fields such as glycoengineering.

  17. Original Research Hepatitis B virus seroprevalence among ...

    African Journals Online (AJOL)

    genetic markers, and liver biopsy, amongst others.9,10 In. Malawi, screening for hepatitis B virus surface antigen. (HBsAg) in public hospitals .... produced in response to the core HBV antigen and persist for life, suggesting a past horizontal transmission in childhood and adulthood.21 Detection of HBV DNA could be useful.

  18. 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.

  19. Isolation, purification, and radiolabeling of a novel 120-kD surface protein on Blastomyces dermatitidis yeasts to detect antibody in infected patients

    International Nuclear Information System (INIS)

    Klein, B.S.; Jones, J.M.

    1990-01-01

    No well-defined Blastomyces-specific antigens are currently available. We used sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting to identify immunologically active molecules in the cell wall of B. dermatitidis. A major immunoreactive 120-kD protein (WI-1) was present in all five strains studied and comprised 5% of the protein in the cell wall extract obtained after freezing and thawing yeast cells. WI-1 was recognized by serum from all 10 patients with blastomycosis but by none of those from 5 patients with histoplasmosis. It was purified by electroelution, radiolabeled with 125I, and incorporated into a radioimmunoassay (RIA) for serodiagnosis of blastomycosis. Antibody to WI-1 was detected in 58 (85%) of 68 patients with blastomycosis (geometric mean titer, 1:2,981), in two (3%) of 73 patients with histoplasmosis, coccidioidomycosis, sporotrichosis, or candidiasis (titers, 1:86 and 1:91) and in none of 44 healthy persons. WI-1 was shown to be a surface molecule abundant on B. dermatitidis yeasts that were indirectly stained with serum from a rabbit immunized with WI-1. Approximately 0.93 pg of WI-1 or 4.7 x 10(6) WI-1 molecules were found on the surface of an individual yeast using an antigen-inhibition RIA; none was found on Histoplasma capsulatum or Candida albicans yeasts. We conclude that WI-1 is a novel, immunologically active surface molecule on the invasive form of B. dermatitidis and that WI-1 can be used to reliably detect antibody and study the immunopathogenesis of blastomycosis

  20. Isolation, purification, and radiolabeling of a novel 120-kD surface protein on Blastomyces dermatitidis yeasts to detect antibody in infected patients

    Energy Technology Data Exchange (ETDEWEB)

    Klein, B.S.; Jones, J.M.

    1990-01-01

    No well-defined Blastomyces-specific antigens are currently available. We used sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting to identify immunologically active molecules in the cell wall of B. dermatitidis. A major immunoreactive 120-kD protein (WI-1) was present in all five strains studied and comprised 5% of the protein in the cell wall extract obtained after freezing and thawing yeast cells. WI-1 was recognized by serum from all 10 patients with blastomycosis but by none of those from 5 patients with histoplasmosis. It was purified by electroelution, radiolabeled with 125I, and incorporated into a radioimmunoassay (RIA) for serodiagnosis of blastomycosis. Antibody to WI-1 was detected in 58 (85%) of 68 patients with blastomycosis (geometric mean titer, 1:2,981), in two (3%) of 73 patients with histoplasmosis, coccidioidomycosis, sporotrichosis, or candidiasis (titers, 1:86 and 1:91) and in none of 44 healthy persons. WI-1 was shown to be a surface molecule abundant on B. dermatitidis yeasts that were indirectly stained with serum from a rabbit immunized with WI-1. Approximately 0.93 pg of WI-1 or 4.7 x 10(6) WI-1 molecules were found on the surface of an individual yeast using an antigen-inhibition RIA; none was found on Histoplasma capsulatum or Candida albicans yeasts. We conclude that WI-1 is a novel, immunologically active surface molecule on the invasive form of B. dermatitidis and that WI-1 can be used to reliably detect antibody and study the immunopathogenesis of blastomycosis.

  1. Pheromone communication in the fission yeast Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Nielsen, O; Davey, William John; Nielsen, Olaf

    1995-01-01

    Conjugation between two haploid yeast cells is generally controlled by the reciprocal action of diffusible mating pheromones, cells of each mating type releasing pheromones that induce mating-specific changes in cells of the opposite type. Recent studies into pheromone signalling in the fission...

  2. Merkel Cell Polyomavirus Small T Antigen Drives Cell Motility via Rho-GTPase-Induced Filopodium Formation.

    Science.gov (United States)

    Stakaitytė, Gabrielė; Nwogu, Nnenna; Dobson, Samuel J; Knight, Laura M; Wasson, Christopher W; Salguero, Francisco J; Blackbourn, David J; Blair, G Eric; Mankouri, Jamel; Macdonald, Andrew; Whitehouse, Adrian

    2018-01-15

    Cell motility and migration is a complex, multistep, and multicomponent process intrinsic to progression and metastasis. Motility is dependent on the activities of integrin receptors and Rho family GTPases, resulting in the remodeling of the actin cytoskeleton and formation of various motile actin-based protrusions. Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high likelihood of recurrence and metastasis. Merkel cell polyomavirus (MCPyV) is associated with the majority of MCC cases, and MCPyV-induced tumorigenesis largely depends on the expression of the small tumor antigen (ST). Since the discovery of MCPyV, a number of mechanisms have been suggested to account for replication and tumorigenesis, but to date, little is known about potential links between MCPyV T antigen expression and the metastatic nature of MCC. Previously, we described the action of MCPyV ST on the microtubule network and how it impacts cell motility and migration. Here, we demonstrate that MCPyV ST affects the actin cytoskeleton to promote the formation of filopodia through a mechanism involving the catalytic subunit of protein phosphatase 4 (PP4C). We also show that MCPyV ST-induced cell motility is dependent upon the activities of the Rho family GTPases Cdc42 and RhoA. In addition, our results indicate that the MCPyV ST-PP4C interaction results in the dephosphorylation of β 1 integrin, likely driving the cell motility pathway. These findings describe a novel mechanism by which a tumor virus induces cell motility, which may ultimately lead to cancer metastasis, and provides opportunities and strategies for targeted interventions for disseminated MCC. IMPORTANCE Merkel cell polyomavirus (MCPyV) is the most recently discovered human tumor virus. It causes the majority of cases of Merkel cell carcinoma (MCC), an aggressive skin cancer. However, the molecular mechanisms implicating MCPyV-encoded proteins in cancer development are yet to be fully elucidated. This study builds

  3. 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

  4. Radioprotection by butylated hydroxytoluene against radiation induced genetic and lethal effects in yeast

    International Nuclear Information System (INIS)

    Anjaria, Kshiti B.; Shirsath, Kapil B.; Sreedevi, B.

    2012-01-01

    Butylated hydroxytoluene (BHT) is a phenolic antioxidant which is used widely in food industry as a food preservative for fats and oils; in plastics and also in cosmetics and fragrances. Generally it is considered harmless, however BHT has also shown potentiation of radiation effects in some studies. The objective of this study was to test the modifying properties of BHT in a eukaryotic model system comprising of Saccharomyces cerevisiae D7, a diploid yeast strain, against the genotoxic effects induced by 60 Co gamma radiation. Log phase cells were exposed to 100 Gy of radiation in the absence or presence of 0.025-0.25 mM BHT. In another set of experiments, log phase cells were exposed to 400 Gy of radiation in the absence or presence of 0.025 mM BHT. Cells were washed and plated. The results indicated that presence of BHT reduced the frequencies of gene conversion and back mutation as well as cell killing induced by radiation. The results obtained in the present study can be explained on the basis of potent radical scavenging ability of BHT, which is a well known standard antioxidant and whose free radical scavenging ability has been very well established and documented using stable free radical DPPH. (author)

  5. 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.

  6. MYC-induced nuclear antigen (MINA) and preeclampsia.

    Science.gov (United States)

    Martinez-Fierro, Margarita L; Reyes-Oliva, Edwin A; Cabral-Pacheco, Griselda A; Garza-Veloz, Idalia; Aceves-Medina, Maria C; Luevano, Martha; Barbosa-Cisneros, Olga Y; Galvan-Valencia, Marisol; Yahuaca-Mendoza, Patricia; Delgado-Enciso, Ivan; Zamudio-Osuna, Michelle; Rodriguez-Sanchez, Iram P; Vazquez-Castro, Rosbel; Guerrero-Saucedo, Marycruz

    2016-05-01

    Inadequate trophoblast invasion and the subsequent inflammatory response have been implicated in preeclampsia (PE) pathogenesis. Because MYC-induced nuclear antigen (MINA) gene expression is involved in cell proliferation and differentiation, inflammatory response modulation, and the unpaired regulation of which is associated with human diseases, we sought to investigate the connection between MINA and PE. The aim of this study was to evaluate the possible relationship between the MINA rs4857304 variant and susceptibility to PE development as well as to estimate placental MINA gene expression and its association with PE. About 242 pregnant women (126 PE cases and 116 controls) were included. MINA genotyping and gene expression were evaluated by quantitative real-time polymerase chain reaction using TaqMan probes. The G/G genotype of the MINA rs4857304 variant was associated with severe PE (p = 0.027, OR = 1.8, 95% CI = 1.8-3.2). Carriers of one G allele of the MINA rs4857304 variant exhibited a 1.7-fold increased risk of severe PE (p = 0.029, 95% CI = 1.1-3.0). MINA was underexpressed in preeclamptic placentas and MINA expression differed between the mild and severe PE groups. Differences in the expression levels of MINA were found among women with the T/T genotype of the rs4857304 polymorphism and carriers of at least one G allele (p = 0.024). PE and its severity are associated with the underexpression of placental MINA, and the G/G genotype of the MINA rs4857304 variant may modify the risk of severe PE among the PE cases evaluated.

  7. Differentiation of the emerging human pathogens Trichosporon asahii and Trichosporon asteroides from other pathogenic yeasts and moulds by using species-specific monoclonal antibodies.

    Directory of Open Access Journals (Sweden)

    Genna E Davies

    Full Text Available The fungal genus Trichosporon contains emerging opportunistic pathogens of humans, and is the third most commonly isolated non-candidal yeast from humans. Trichosporon asahii and T. asteroides are the most important species causing disseminated disease in immunocompromised patients, while inhalation of T. asahii spores is the most important cause of summer-type hypersensitivity pneumonitis in healthy individuals. Trichosporonosis is misdiagnosed as candidiasis or cryptococcosis due to a lack of awareness and the ambiguity of diagnostic tests for these pathogens. In this study, hybridoma technology was used to produce two murine monoclonal antibodies (MAbs, CA7 and TH1, for detection and differentiation of Trichosporon from other human pathogenic yeasts and moulds. The MAbs react with extracellular antigens from T. asahii and T. asteroides, but do not recognise other related Trichosporon spp., or unrelated pathogenic yeasts and moulds including Candida, Cryptococcus, Aspergillus, Fusarium, and Scedosporium spp., or the etiologic agents of mucormycosis. Immunofluorescence and Western blotting studies show that MAb CA7, an immunoglobulin G1 (IgG1, binds to a major 60 kDa glycoprotein antigen produced on the surface of hyphae, while TH1, an immunoglobulin M (IgM, binds to an antigen produced on the surface of conidia. The MAbs were used in combination with a standard mycological growth medium (Sabouraud Dextrose Agar to develop an enzyme-linked immunosorbent assay (ELISA for differentiation of T. asahii from Candida albicans and Cryptococcus neoformans in single and mixed species cultures. The MAbs represent a major advance in the identification of T. asahii and T. asteroides using standard mycological identification methods.

  8. RESEARCH OF ANTIGEN AND ANTIBODIES FROM RETROVIRUSES, CMV AND HBV AMONG PRISONERS OF THE PENITENTIARY COMPLEX OF THE REGION OF CAMPINAS, SP, BRAZIL

    Directory of Open Access Journals (Sweden)

    Neusa Maria OSTI

    1998-07-01

    Full Text Available Some viruses of the families Retroviridae, such as Human T Lymphotropic Virus (HTLV; Herpesviridae as the Cytomegalovirus (CMV and Hepadnaviridae such as the Hepatitis B Virus (HBV are liable to be co-transmitted with the Human Immunodeficiency Virus (HIV. Since prisoners are exposed to several and important risk factors involved in the transmission of HIV and the above mentioned viruses, male inmates from the penitentiary complex of Campinas, SP, Brazil, including HIV + and HIV - ones, were examined for the presence of HTLV-I and/or II antibodies; IgG and IgM anti-CMV antibodies, and the research of the superficial hepatitis B antigen (HBsAg. The presence of anti-HTLV-I and/or II was determined by the Western Blot (WB technique, whereas IgG and IgM anti-CMV and the search of HBsAg were carried out by the Microparticle Enzyme Immunoassay (MEIA-Abbott Lab.With regard to anti-HTLV-I and/or II, 58.3% (14/24-Number of positive reactions/number of sera examined were reactive among the anti-HIV positive sera. Conversely, only 12.5% (3/24 among the HIV- negative sera showed positive reactions to HTLV-I and/or II antibodies. When looking for IgG anti-CMV percentages of 97.7% (43/44 and 95% (38/40 were obtained for anti-HIV positive and negative sera, respectively. As to IgM anti-CMV antibodies 11.36% (5/44 and 2.5% (1/40 of reactive sera were found for anti-HIV positive and negative, respectively. The HBsAg was found in 12.8% (5/39 of the sera which were anti-HIV positive.Alguns vírus das famílias Retroviridae, tais como, o Vírus do Linfoma Humano de Células T ( HTLV; Herpesviridae, tais como o Vírus Citomegálico (CMV e da Hepatite B (HBV podem ser co-transmitidos com o Vírus da Imunodeficiência Adquirida (HIV. Uma vez que prisioneiros estão expostos a diversos fatores de risco envolvidos na transmissão do HIV e dos vírus acima mencionados, prisioneiros do sexo masculino do Complexo Penitenciário de Campinas, SP, Brasil, incluindo aqueles

  9. Liver Function In Patients With Homozygous Sickle Cell Disease ...

    African Journals Online (AJOL)

    Using the sensitive ELISA technique, 213 patients with sickle cell anemia (112 males and 101 females) aged 6 months to 18 years were screened for Hepatitis B infection using Hepatitis B surface antigen (HBsAg) and antibody to Hepatitis B core antigen. A biochemical evaluation of liver function was carried out on all ...

  10. Prion-based memory of heat stress in yeast.

    Science.gov (United States)

    Chernova, Tatiana A; Chernoff, Yury O; Wilkinson, Keith D

    2017-05-04

    Amyloids and amyloid-based prions are self-perpetuating protein aggregates which can spread by converting a normal protein of the same sequence into a prion form. They are associated with diseases in humans and mammals, and control heritable traits in yeast and other fungi. Some amyloids are implicated in biologically beneficial processes. As prion formation generates reproducible memory of a conformational change, prions can be considered as molecular memory devices.  We have demonstrated that in yeast, stress-inducible cytoskeleton-associated protein Lsb2 forms a metastable prion in response to high temperature. This prion promotes conversion of other proteins into prions and can persist in a fraction of cells for a significant number of cell generations after stress, thus maintaining the memory of stress in a population of surviving cells. Acquisition of an amino acid substitution required for Lsb2 to form a prion coincides with acquisition of increased thermotolerance in the evolution of Saccharomyces yeast. Thus the ability to form an Lsb2 prion in response to stress coincides with yeast adaptation to growth at higher temperatures. These findings intimately connect prion formation to the cellular response to environmental stresses.

  11. ADCC-Mediated CD56DIM NK Cell Responses Are Associated with Early HBsAg Clearance in Acute HBV Infection.

    Science.gov (United States)

    Yu, Wen-Han; Cosgrove, Cormac; Berger, Christoph T; Cheney, Patrick C; Krykbaeva, Marina; Kim, Arthur Y; Lewis-Ximenez, Lia; Lauer, Georg M; Alter, Galit

    2018-01-01

    Hepatitis B virus (HBV) affects up to 400 million people worldwide and accounts for approximately one million deaths per year from liver pathologies. Current treatment regimens are effective in suppressing viremia but usually have to be taken indefinitely, warranting research into new therapeutic approaches. Acute HBV infection in adults almost universally results in resolution of viremia, with the exception of immunocompromised persons, suggesting that the immune response can functionally cure or even eradicate HBV infection. Because immunophenotypic and functional studies have implicated a role for Natural Killer (NK) cells in HBV clearance during acute infection, we hypothesized that a distinct NK-cell profile exists in acute HBV infection that could provide information for the mechanism of HBV clearance. Using multivariate flow cytometry, we evaluated the expression of key activating and inhibitory receptors on NK cells, and their ability to respond to classic target cell lines. Multivariate analysis revealed selective perturbation of the CD56 dim NK-cell subset during acute infection, displaying low levels of NKp46+, NKp30+, CD160+ and CD161+ cells. Intriguingly, the CD56 dim NK-cell profile predicted time to HBV surface antigen (HBsAg) clearance from the blood, and distinct NK-cell profiles predicted early (NKp30, CD94, CD161) and late clearance (KIR3DL1, CD158a, perforin, NKp46). Finally, functional analysis demonstrated that early and late clearance tracked with elevated degranulation (CD107a) or IFNγ production, respectively, in response to ADCC-mediated activation. The cytolytic CD56 dim NK-cell subset is selectively activated in acute HBV infection and displays distinct phenotypic and functional profiles associated with efficient and early control of HBV, implicating antibody-mediated cytolytic NK-cell responses in the early control and functional cure of HBV infection.

  12. Therapeutic activity of a Saccharomyces cerevisiae-based probiotic and inactivated whole yeast on vaginal candidiasis.

    Science.gov (United States)

    Pericolini, Eva; Gabrielli, Elena; Ballet, Nathalie; Sabbatini, Samuele; Roselletti, Elena; Cayzeele Decherf, Amélie; Pélerin, Fanny; Luciano, Eugenio; Perito, Stefano; Jüsten, Peter; Vecchiarelli, Anna

    2017-01-02

    Vulvovaginal candidiasis is the most prevalent vaginal infection worldwide and Candida albicans is its major agent. Vulvovaginal candidiasis is characterized by disruption of the vaginal microbiota composition, as happens following large spectrum antibiotic usage. Recent studies support the effectiveness of oral and local probiotic treatment for prevention of recurrent vulvovaginal candidiasis. Saccharomyces cerevisiae is a safe yeast used as, or for, the production of ingredients for human nutrition and health. Here, we demonstrate that vaginal administration of probiotic Saccharomyces cerevisiae live yeast (GI) and, in part, inactivated whole yeast Saccharomyces cerevisiae (IY), used as post-challenge therapeutics, was able to positively influence the course of vaginal candidiasis by accelerating the clearance of the fungus. This effect was likely due to multiple interactions of Saccharomyces cerevisiae with Candida albicans. Both live and inactivated yeasts induced coaggregation of Candida and consequently inhibited its adherence to epithelial cells. However, only the probiotic yeast was able to suppress some major virulence factors of Candida albicans such as the ability to switch from yeast to mycelial form and the capacity to express several aspartyl proteases. The effectiveness of live yeast was higher than that of inactivated whole yeast suggesting that the synergy between mechanical effects and biological effects were dominant over purely mechanical effects. The protection of epithelial cells to Candida-induced damage was also observed. Overall, our data show for the first time that Saccharomyces cerevisiae-based ingredients, particularly the living cells, can exert beneficial therapeutic effects on a widespread vaginal mucosal infection.

  13. Antigen presentation by resting B cells. Radiosensitivity of the antigen-presentation function and two distinct pathways of T cell activation

    International Nuclear Information System (INIS)

    Ashwell, J.D.; DeFranco, A.L.; Paul, W.E.; Schwartz, R.H.

    1984-01-01

    In this report we have examined the ability of small resting B cells to act as antigen-presenting cells (APC) to antigen-specific MHC-restricted T cells as assessed by either T cell proliferation or T cell-dependent B cell stimulation. We found that 10 of 14 in vitro antigen-specific MHC-restricted T cell clones and lines and three of four T cell hybridomas could be induced to either proliferate or secrete IL-2 in the presence of lightly irradiated (1,000 rads) purified B cells and the appropriate foreign antigen. All T cell lines and hybridomas were stimulated to proliferate or make IL-2 by macrophage- and dendritic cell-enriched populations and all T cells tested except one hybridoma caused B cell activation when stimulated with B cells as APC. Furthermore, lightly irradiated, highly purified syngeneic B cells were as potent a source of APC for inducing B cell activation as were low density dendritic and macrophage-enriched cells. Lymph node T cells freshly taken from antigen-primed animals were also found to proliferate when cultured with purified B cells and the appropriate antigen. This APC function was easily measured when the cells were irradiated with 1,000 rads, but was greatly diminished or absent when they were irradiated with 3,300 rads. In addition, this radiosensitivity allowed us to easily distinguish B cell antigen presentation from presentation by the dendritic cell and macrophage, as the latter was resistant to 3,300 rads. Finally, one T cell clone that failed to proliferate when B cells were used as APC was able to recruit allogeneic B cells to proliferate in the presence of syngeneic B cells and the appropriate antigen. This result suggests that there are at least two distinct pathways of activation in T cells, one that leads to T cell proliferation and one that leads to the secretion of B cell recruitment factor(s)

  14. Effects of photoprotection and reversible inactivation of the yeast Candida guilliermondii, induced by 313 nm light

    International Nuclear Information System (INIS)

    Frajkin, G.Ya.; Pospelov, M.E.; Rubin, L.B.

    1976-01-01

    The results of studies on the effect of near uv light on the yeast Candida guilliermondii are presented. It was shown that certain doses of 313 nm light inactivated the yeast. The detailed affect is shown in the loss of the ability of the cells to form microcolonies and outwardly does not differ from inactivation caused by 254 nm uv. It was concluded that the cell destruction caused by the 313 nm light was not due to damage to DNA. Experiments in which yeast cells were inactivated by 313 nm light before plating on agar and held for some time in a non-nutrient medium permitted observation of recovery of their viability. A difference was shown in the level of repair of yeasts irradiated by 313 nm light (up to 100% recovery) and 254 nm light (60% recovery). The nature of the dependence of the photoprotection on the 313 nm light dose was determined. A decrease in photoprotection was noted, starting with 7x10 -7 einstein/cm 2 , with its complete disappearance upon further dose increase. It is suggested that, in this recovery of the yeast, some other, thus far unknown, mechanism participates. Data were obtained on the survival of yeast irradiated with lethal uv doses. Of special importance, in the authors' opinion, is the fact that, for the photoprotection effect to appear, some time is needed between actions of the 313 and 254 nm lights, which suggests a photoinduced formation in the yeast cells of compounds that protect them from lethal injury

  15. Mutator suppression and escape from replication error-induced extinction in yeast.

    Directory of Open Access Journals (Sweden)

    Alan J Herr

    2011-10-01

    Full Text Available Cells rely on a network of conserved pathways to govern DNA replication fidelity. Loss of polymerase proofreading or mismatch repair elevates spontaneous mutation and facilitates cellular adaptation. However, double mutants are inviable, suggesting that extreme mutation rates exceed an error threshold. Here we combine alleles that affect DNA polymerase δ (Pol δ proofreading and mismatch repair to define the maximal error rate in haploid yeast and to characterize genetic suppressors of mutator phenotypes. We show that populations tolerate mutation rates 1,000-fold above wild-type levels but collapse when the rate exceeds 10⁻³ inactivating mutations per gene per cell division. Variants that escape this error-induced extinction (eex rapidly emerge from mutator clones. One-third of the escape mutants result from second-site changes in Pol δ that suppress the proofreading-deficient phenotype, while two-thirds are extragenic. The structural locations of the Pol δ changes suggest multiple antimutator mechanisms. Our studies reveal the transient nature of eukaryotic mutators and show that mutator phenotypes are readily suppressed by genetic adaptation. This has implications for the role of mutator phenotypes in cancer.

  16. Antigen-specific tolerance of human alpha1-antitrypsin induced by helper-dependent adenovirus.

    Science.gov (United States)

    Cerullo, V; McCormack, W; Seiler, M; Mane, V; Cela, R; Clarke, C; Rodgers, J R; Lee, B

    2007-12-01

    As efficient and less toxic virus-derived gene therapy vectors are developed, a pressing problem is to avoid immune response to the therapeutic gene product. Secreted therapeutic proteins potentially represent a special problem, as they are readily available to professional antigen-presenting cells throughout the body. Some studies suggest that immunity to serum proteins can be avoided in some mouse strains by using tissue-specific promoters. Here we show that expression of human alpha1-antitrypsin (AAT) was nonimmunogenic in the immune-responsive strain C3H/HeJ, when expressed from helper-dependent (HD) vectors using ubiquitous as well as tissue-specific promoters. Coadministration of less immunogenic HD vectors with an immunogenic first-generation vector failed to immunize, suggesting immune suppression rather than immune stealth. Indeed, mice primed with HD vectors were tolerant to immune challenge with hAAT emulsified in complete Freund's adjuvant. Such animals developed high-titer antibodies to coemulsified human serum albumin, showing that tolerance was antigen specific. AAT-specific T cell responses were depressed in tolerized animals, suggesting that tolerance affects both T and B cells. These results are consistent with models of high-dose tolerance of B cells and certain other suppressive mechanisms, and suggest that a high level of expression from HD vectors can be sufficient to induce specific immune tolerance to serum proteins.

  17. Influence of sodium chloride on wine yeast fermentation performance

    Directory of Open Access Journals (Sweden)

    Stilianos Logothetis

    2010-06-01

    Full Text Available Stilianos Logothetis1, Elias T Nerantzis2, Anna Gioulioti3, Tasos Kanelis2, Tataridis Panagiotis2, Graeme Walker11University of Abertay Dundee, School of Contemporary Sciences, Dundee, Scotland; 2TEI of Athens Department of Oenology and Spirit Technology, Biotechnology and Industrial Fermentations Lab Agiou Spiridonos, Athens, Greece; 3Ampeloiniki SA Industrial Park Thermi, Thessaloniki, GreeceAbstract: This paper concerns research into the influence of salt (sodium chloride on growth, viability and fermentation performance in a winemaking strain of the yeast, Saccharomyces cerevisiae. Experimental fermentations were conducted in both laboratory-scale and industrial-scale experiments. Preculturing yeasts in elevated levels of sodium chloride, or salt “preconditioning” led to improved fermentation performance. This was manifest by preconditioned yeasts having an improved capability to ferment high-sugar containing media with increased cell viability and with elevated levels of produced ethanol. Salt-preconditioning most likely influenced the stress-tolerance of yeasts by inducing the synthesis of key metabolites such as trehalose and glycerol. These compounds may act to improve cells’ ability to withstand osmostress and ethanol toxicity during fermentations of grape must. Industrial-scale trials using salt-preconditioned yeasts verified the benefit of this novel physiological cell engineering approach to practical winemaking fermentations.Keywords: salt, preconditioning, fermentation performance, Saccharomyces cerevisiae, wine

  18. Prevalence and risk factors of hepatitis B and C virus infections in an impoverished urban community in Dhaka, Bangladesh

    Directory of Open Access Journals (Sweden)

    Salam Mohammed A

    2010-07-01

    Full Text Available Abstract Background Viral hepatitis is a serious global public health problem affecting billions of people globally, and both hepatitis B virus (HBV and hepatitis C virus (HCV infections are rapidly spreading in the developing countries including Bangladesh due to the lack of health education, poverty, illiteracy and lack of hepatitis B vaccination. Also there is lack of information on their prevalence among the general population. So, a population-based serological survey was conducted in Dhaka to determine the prevalence and risk factors of HBV and HCV infections. Methods Healthy individuals were selected for demographic and behavioural characteristics by stratified cluster sampling and blood tested for hepatitis B surface antigen (HBsAg, antibody to HBV core antigen (anti-HBc, and anti-HCV antibodies (anti-HCV. Results From June 2005-November 2006, 1997 participants were screened for HBsAg, anti-HBc and anti-HCV, 738 (37% were males with mean (SD age of 24 (14 years. HBV-seropositivity was documented in 582 (29% participants: 14 (0.7% were positive for HBsAg, 452 (22.6% for anti-HBc and 116 (5.8% for both HBsAg and anti-HBc. Four (0.2% participants were positive for anti-HCV, and another five (0.3% for both anti-HBc and anti-HCV. Ninety-six/246 (39% family members residing at same households with HBsAg positive participants were also HBV-seropositive [74 (30.1% for anti-HBc and 22 (8.9% for both HBsAg and anti-HBc], which was significantly higher among family members (39% than that of study participants (29% (OR 1.56; p Conclusions The results indicate intermediate level of endemicity of HBV infection in Dhaka community, with much higher prevalence among family members of HBsAg positive individuals but low prevalence of HCV infections, clearly indicating need for universal hepatitis B vaccination. The use of disposable needles for ear-nose-body piercing need to be promoted through public awareness programmes as a preventive strategy.

  19. The splicing mutant of the human tumor suppressor protein DFNA5 induces programmed cell death when expressed in the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Van Rossom, Sofie; Op de Beeck, Ken; Franssens, Vanessa; Swinnen, Erwin; Schepers, Anne; Ghillebert, Ruben; Caldara, Marina; Van Camp, Guy; Winderickx, Joris

    2012-01-01

    DFNA5 was first identified as a gene responsible for autosomal dominant deafness. Different mutations were found, but they all resulted in exon 8 skipping during splicing and premature termination of the protein. Later, it became clear that the protein also has a tumor suppression function and that it can induce apoptosis. Epigenetic silencing of the DFNA5 gene is associated with different types of cancers, including gastric and colorectal cancers as well as breast tumors. We introduced the wild-type and mutant DFNA5 allele in the yeast Saccharomyces cerevisiae. The expression of the wild-type protein was well tolerated by the yeast cells, although the protein was subject of degradation and often deposited in distinct foci when cells entered the diauxic shift. In contrast, cells had problems to cope with mutant DFNA5 and despite an apparent compensatory reduction in expression levels, the mutant protein still triggered a marked growth defect, which in part can be ascribed to its interaction with mitochondria. Consistently, cells with mutant DFNA5 displayed significantly increased levels of ROS and signs of programmed cell death. The latter occurred independently of the yeast caspase, Mca1, but involved the mitochondrial fission protein, Fis1, the voltage-dependent anion channel protein, Por1 and the mitochondrial adenine nucleotide translocators, Aac1 and Aac3. Recent data proposed DFNA5 toxicity to be associated to a globular domain encoded by exon 2–6. We confirmed these data by showing that expression of solely this domain confers a strong growth phenotype. In addition, we identified a point mutant in this domain that completely abrogated its cytotoxicity in yeast as well as human Human Embryonic Kidney 293T cells (HEK293T). Combined, our data underscore that the yeast system offers a valuable tool to further dissect the apoptotic properties of DFNA5.

  20. The splicing mutant of the human tumor suppressor protein DFNA5 induces programmed cell death when expressed in the yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Van Rossom, Sofie [Department of Biology, Functional Biology, KU Leuven, Leuven-Heverlee (Belgium); Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp, Wilrijk-Antwerp (Belgium); Op de Beeck, Ken [Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp, Wilrijk-Antwerp (Belgium); Franssens, Vanessa; Swinnen, Erwin [Department of Biology, Functional Biology, KU Leuven, Leuven-Heverlee (Belgium); Schepers, Anne [Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp, Wilrijk-Antwerp (Belgium); Ghillebert, Ruben; Caldara, Marina [Department of Biology, Functional Biology, KU Leuven, Leuven-Heverlee (Belgium); Van Camp, Guy [Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp, Wilrijk-Antwerp (Belgium); Winderickx, Joris, E-mail: guy.vancamp@ua.ac.be, E-mail: joris.winderickx@bio.kuleuven.be [Department of Biology, Functional Biology, KU Leuven, Leuven-Heverlee (Belgium)

    2012-07-25

    DFNA5 was first identified as a gene responsible for autosomal dominant deafness. Different mutations were found, but they all resulted in exon 8 skipping during splicing and premature termination of the protein. Later, it became clear that the protein also has a tumor suppression function and that it can induce apoptosis. Epigenetic silencing of the DFNA5 gene is associated with different types of cancers, including gastric and colorectal cancers as well as breast tumors. We introduced the wild-type and mutant DFNA5 allele in the yeast Saccharomyces cerevisiae. The expression of the wild-type protein was well tolerated by the yeast cells, although the protein was subject of degradation and often deposited in distinct foci when cells entered the diauxic shift. In contrast, cells had problems to cope with mutant DFNA5 and despite an apparent compensatory reduction in expression levels, the mutant protein still triggered a marked growth defect, which in part can be ascribed to its interaction with mitochondria. Consistently, cells with mutant DFNA5 displayed significantly increased levels of ROS and signs of programmed cell death. The latter occurred independently of the yeast caspase, Mca1, but involved the mitochondrial fission protein, Fis1, the voltage-dependent anion channel protein, Por1 and the mitochondrial adenine nucleotide translocators, Aac1 and Aac3. Recent data proposed DFNA5 toxicity to be associated to a globular domain encoded by exon 2–6. We confirmed these data by showing that expression of solely this domain confers a strong growth phenotype. In addition, we identified a point mutant in this domain that completely abrogated its cytotoxicity in yeast as well as human Human Embryonic Kidney 293T cells (HEK293T). Combined, our data underscore that the yeast system offers a valuable tool to further dissect the apoptotic properties of DFNA5.

  1. Inhibition effects of 125I-triplex forming oligonucleotide to hepatoma cells

    International Nuclear Information System (INIS)

    Lv Zhongwei; Hou Min; Cai Haidong; Yuan Xueyu; Yang Yuehua; Yuan Shidong; He Junmin

    2007-01-01

    Objective: Triplex forming oligonucleotide (TFO) has been reported as a new antigene strategy. The purpose of this study was to observe the inhibition effects of 125 I-TFO on hepatoma cells and to investigate the possibility of using 125 I-TFO as an antigene radiotherapy technique for hepatocellular carcinoma (HCC) related to HBV. Methods: TFO complementary to the initiator of S gene of HBV was synthesized and labeled with 125 I. HepG2.2.15 cells, in which HBV genome was integrated, were incubated with 125 I-TFO, TFO and 125 I respectively. After incubation, hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) of each group were assayed with ELISA and the survival rate of cells in each group was determined with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide (MTT) reduction assay. Results: 125 I-TFO showed a high stability with a radiolabeling rate of >93%. The radiochemical purity of labeled compound was 90.8%, 81.1% and 73.2% respectively after 12, 48 and 72 h at 37 degree C. The peak inhibition effect of 125 I-TFO on synthesizing HBsAg and HBeAg by HepG2.2.15 cells were found at 48 h after transfection, with significantly the highest inhibition rate of 45.2% for HBsAg and 74.5% for HBeAg expression among the three groups(P 125 I-TFO may inhibit the antigen expression of HBV and the growth of hepatocarcinoma cells, thus it may provide a new approach to develop gene-based radiotherapeutic pharmaceuticals for anti-HBV and HCC. (authors)

  2. Bridge-Induced Translocation between NUP145 and TOP2 Yeast Genes Models the Genetic Fusion between the Human Orthologs Associated With Acute Myeloid Leukemia

    Directory of Open Access Journals (Sweden)

    Valentina Tosato

    2017-09-01

    Full Text Available In mammalian organisms liquid tumors such as acute myeloid leukemia (AML are related to spontaneous chromosomal translocations ensuing in gene fusions. We previously developed a system named bridge-induced translocation (BIT that allows linking together two different chromosomes exploiting the strong endogenous homologous recombination system of the yeast Saccharomyces cerevisiae. The BIT system generates a heterogeneous population of cells with different aneuploidies and severe aberrant phenotypes reminiscent of a cancerogenic transformation. In this work, thanks to a complex pop-out methodology of the marker used for the selection of translocants, we succeeded by BIT technology to precisely reproduce in yeast the peculiar chromosome translocation that has been associated with AML, characterized by the fusion between the human genes NUP98 and TOP2B. To shed light on the origin of the DNA fragility within NUP98, an extensive analysis of the curvature, bending, thermostability, and B-Z transition aptitude of the breakpoint region of NUP98 and of its yeast ortholog NUP145 has been performed. On this basis, a DNA cassette carrying homologous tails to the two genes was amplified by PCR and allowed the targeted fusion between NUP145 and TOP2, leading to reproduce the chimeric transcript in a diploid strain of S. cerevisiae. The resulting translocated yeast obtained through BIT appears characterized by abnormal spherical bodies of nearly 500 nm of diameter, absence of external membrane and defined cytoplasmic localization. Since Nup98 is a well-known regulator of the post-transcriptional modification of P53 target genes, and P53 mutations are occasionally reported in AML, this translocant yeast strain can be used as a model to test the constitutive expression of human P53. Although the abnormal phenotype of the translocant yeast was never rescued by its expression, an exogenous P53 was recognized to confer increased vitality to the translocants, in

  3. Fatty acids from oleaginous yeasts and yeast-like fungi and their potential applications.

    Science.gov (United States)

    Xue, Si-Jia; Chi, Zhe; Zhang, Yu; Li, Yan-Feng; Liu, Guang-Lei; Jiang, Hong; Hu, Zhong; Chi, Zhen-Ming

    2018-02-01

    Oleaginous yeasts, fatty acids biosynthesis and regulation in the oleaginous yeasts and the fatty acids from the oleaginous yeasts and their applications are reviewed in this article. Oleaginous yeasts such as Rhodosporidium toruloides, Yarrowia lipolytica, Rhodotorula mucilaginosa, and Aureobasidium melanogenum, which can accumulate over 50% lipid of their cell dry weight, have many advantages over other oleaginous microorganisms. The fatty acids from the oleaginous yeasts have many potential applications. Many oleaginous yeasts have now been genetically modified to over-produce fatty acids and their derivatives. The most important features of the oleaginous yeasts are that they have special enzymatic systems for enhanced biosynthesis and regulation of fatty acids in their lipid particles. Recently, some oleaginous yeasts such as R. toruloides have been found to have a unique fatty acids synthetase and other oleaginous yeasts such as A. melanogenum have a unique highly reducing polyketide synthase (HR-PKS) involved in the biosynthesis of hydroxyl fatty acids. It is necessary to further enhance lipid biosynthesis using metabolic engineering and explore new applications of fatty acids in biotechnology.

  4. Hyphal-like extension and pseudohyphal formation in industrial strains of yeasts induced by isoamyl alcohol

    Directory of Open Access Journals (Sweden)

    Ceccato-Antonini Sandra Regina

    2002-01-01

    Full Text Available Yeasts can produce pseudohyphae and hyphal-like extensions under certain growth conditions like isoamyl alcohol (IAA induction, a chief constituent of fusel oil, which is a subproduct from the ethanolic fermentation. The morphology switch from yeast to a filamentous form can be troublesome to the process. In this work it was studied the influence of fusel alcohols, nitrogen sources (ammonium sulphate and leucine and glifosate (a chemical maturator for sugar cane added to a complex medium on some industrial strains of yeasts isolated from the fermentative process. Two industrial strains showed transition to hyphal-like extensions or pseudohyphae (clusters of cells upon addition of IAA from 0.3 to 0.9% /v. The alterations were reversible when the yeasts were reinoculated in YEPD without IAA. Although pseudohyphae are a result of nitrogen-limited medium, we observed them as a result of IAA addition. No influence of the nitrogen source or isopropilic alcohol or glifosate was detected for any strain studied in the concentrations used.

  5. Characterization of the interaction of yeast enolase with polynucleotides.

    Science.gov (United States)

    al-Giery, A G; Brewer, J M

    1992-09-23

    Yeast enolase is inhibited under certain conditions by DNA. The enzyme binds to single-stranded DNA-cellulose. Inhibition was used for routine characterization of the interaction. The presence of the substrate 2-phospho-D-glycerate reduces inhibition and binding. Both yeast enolase isozymes behave similarly. Impure yeast enolase was purified by adsorption onto a single-stranded DNA-cellulose column followed by elution with substrate. Interaction with RNA, double-stranded DNA, or degraded DNA results in less inhibition, suggesting that yeast enolase preferentially binds single-stranded DNA. However, yeast enolase is not a DNA-unwinding protein. The enzyme is inhibited by the short synthetic oligodeoxynucleotides G6, G8 and G10 but not T8 or T6, suggesting some base specificity in the interaction. The interaction is stronger at more acid pH values, with an apparent pK of 5.6. The interaction is prevented by 0.3 M KCl, suggesting that electrostatic factors are important. Histidine or lysine reverse the inhibition at lower concentrations, while phosphate is still more effective. Binding of single-stranded DNA to enolase reduces the reaction of protein histidyl residues with diethylpyrocarbonate. The inhibition of yeast enolase by single-stranded DNA is not total, and suggests the active site is not directly involved in the interaction. Binding of substrate may induce a conformational change in the enzyme that interferes with DNA binding and vice versa.

  6. 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.

  7. Visible light alters yeast metabolic rhythms by inhibiting respiration.

    Science.gov (United States)

    Robertson, James Brian; Davis, Chris R; Johnson, Carl Hirschie

    2013-12-24

    Exposure of cells to visible light in nature or in fluorescence microscopy often is considered to be relatively innocuous. However, using the yeast respiratory oscillation (YRO) as a sensitive measurement of metabolism, we find that non-UV visible light has a significant impact on yeast metabolism. Blue/green wavelengths of visible light shorten the period and dampen the amplitude of the YRO, which is an ultradian rhythm of cell metabolism and transcription. The wavelengths of light that have the greatest effect coincide with the peak absorption regions of cytochromes. Moreover, treating yeast with the electron transport inhibitor sodium azide has similar effects on the YRO as visible light. Because impairment of respiration by light would change several state variables believed to play vital roles in the YRO (e.g., oxygen tension and ATP levels), we tested oxygen's role in YRO stability and found that externally induced oxygen depletion can reset the phase of the oscillation, demonstrating that respiratory capacity plays a role in the oscillation's period and phase. Light-induced damage to the cytochromes also produces reactive oxygen species that up-regulate the oxidative stress response gene TRX2 that is involved in pathways that enable sustained growth in bright visible light. Therefore, visible light can modulate cellular rhythmicity and metabolism through unexpectedly photosensitive pathways.

  8. Total Leishmania antigens with Poly(I:C) induce Th1 protective response.

    Science.gov (United States)

    Sanchez, M V; Eliçabe, R J; Di Genaro, M S; Germanó, M J; Gea, S; García Bustos, M F; Salomón, M C; Scodeller, E A; Cargnelutti, D E

    2017-11-01

    Our proposal was to develop a vaccine based on total Leishmania antigens (TLA) adjuvanted with polyinosinic-polycytidylic acid [Poly(I:C)] able to induce a Th1 response which can provide protection against Leishmania infection. Mice were vaccinated with two doses of TLA-Poly(I:C) administered by subcutaneous route at 3-week interval. Humoral and cellular immune responses induced by the immunization were measured. The protective efficacy of the vaccine was evaluated by challenging mice with infective promastigotes of Leishmania (Leishmania) amazonensis into the footpad. Mice vaccinated with TLA-Poly(I:C) showed a high anti-Leishmania IgG titre, as well as increased IgG1 and IgG2a subclass titres compared with mice vaccinated with the TLA alone. The high IgG2a indicated a Th1 bias response induced by the TLA-Poly(I:C) immunization. Accordingly, the cellular immune response elicited by the formulation was characterized by an increased production of IFN-γ and no significant production of IL-4. The TLA-Poly(I:C) immunization elicited good protection, which was associated with decreased footpad swelling, a lower parasite load and a reduced histopathological alteration in the footpad. Our findings demonstrate a promising vaccine against cutaneous leishmaniasis that is relatively economic and easy to develop and which should be taken into account for preventing leishmaniasis in developing countries. © 2017 John Wiley & Sons Ltd.

  9. Culicoides antigen extract stimulates equine blood mononuclear (BMN) cell proliferation and the release of eosinophil adherence-inducing factor(s).

    Science.gov (United States)

    Mckelvie, J; Foster, A P; Hamblin, A S; Cunningham, F M

    2001-04-01

    Intradermal injection of a Culicoides antigen extract (CAgX) induces T lymphocyte and eosinophil accumulation in the skin of horses with sweet itch. Blood mononuclear (BMN) cells from normal ponies proliferate when stimulated by mitogen (phytohaemagglutinin, PHA) or antigen (tetanus toxoid, TT) and, as shown here, release soluble factor(s) that induce eosinophil adherence. CAgX also caused concentration dependent proliferation of BMN cells from sweet itch and normal ponies [stimulation index: 29 (13) and 17 (7) for BMN cells from sweet itch and normal ponies, respectively during the active phase of disease; 4 microg protein ml(-1)CAgX; 168 h]. A heat labile factor(s) which caused eosinophil adherence was also released [sweet itch ponies: 6.0 (1.6) per cent adherence versus 1.3 (0.4) per cent; normal ponies: 6.6 (0.5) per cent adherence versus 0.9 (0.1) per cent for supernatants from CAgX (4 microg protein ml(-1); 48 hours) stimulated versus unstimulated BMN cells, respectively]. These results suggest that soluble proteins released from T lymphocytes could affect eosinophil function in the lesional skin of sweet itch horses. Copyright 2001 Harcourt Publishers Ltd.

  10. [Relationship between HBeAg from HBsAg positive mothers and regulatory T cells in neonates and its influence on HBV intrauterine transmission].

    Science.gov (United States)

    Hao, H Y; Yang, Z Q; Xu, X X; Wang, X F; Wang, B; Shi, X H; Fu, Z D; Wang, B; Wang, S P

    2017-10-10

    Objective: To explore the relationship between HBeAg in HBsAg positive mothers and CD(4)(+)CD(25)(+) Foxp3 (+)regulatory T cells (Treg) in newborns, as well as how they would influence the increasing risk on HBV intrauterine transmission. Methods: We collected information on general demographic characteristics and delivery on 270 HBsAg positive mothers and their newborns from the Third People's Hospital of Taiyuan. Fluorescence quantitative polymerase chain reaction (FQ-PCR) and chemiluminescence immunoassay (CLIA) were used to detect HBV DNA and HBV serological markers in peripheral blood from both mothers and neonates. The expression of Treg and other immune cells in peripheral blood of neonates were detected with flow cytometry (FCM). Results: Maternal HBeAg positive rates were associated with an increased risk of intrauterine transmission ( OR =4.08, 95 %CI : 1.89-8.82). Rates of Treg in newborns born to HBsAg-positive mothers were higher than that of the negative group ( Z =2.29, P =0.022). Each pair of the subjects was assigned to five different groups according to the HBeAg titers of mothers. Frequencies of both Treg and HBeAg in newborns and HBV DNA in mothers between the above said 5 groups showed similar trends of changing patterns and the differences between groups were statistically significant(χ(2)=18.73, P mother's HBeAg titers were positively related to the percentage of Treg in their newborns ( r(s) =0.19, P =0.039). In addition, the frequencies of Treg were negatively correlated with pDC and CD(4)(+) T cell in their newborns ( r(s) =-0.21, P =0.017; r(s) =-0.23, P =0.009). Conclusion: HBeAg from HBsAg positive mothers might have inhibited the function of neonatal DC cells and T cells to reduce the immune response to HBV by up-regulating the proportion of Treg and finally increased the risk of HBV intrauterine transmission.

  11. Yeast for virus research

    Science.gov (United States)

    Zhao, Richard Yuqi

    2017-01-01

    Budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) are two popular model organisms for virus research. They are natural hosts for viruses as they carry their own indigenous viruses. Both yeasts have been used for studies of plant, animal and human viruses. Many positive sense (+) RNA viruses and some DNA viruses replicate with various levels in yeasts, thus allowing study of those viral activities during viral life cycle. Yeasts are single cell eukaryotic organisms. Hence, many of the fundamental cellular functions such as cell cycle regulation or programed cell death are highly conserved from yeasts to higher eukaryotes. Therefore, they are particularly suited to study the impact of those viral activities on related cellular activities during virus-host interactions. Yeasts present many unique advantages in virus research over high eukaryotes. Yeast cells are easy to maintain in the laboratory with relative short doubling time. They are non-biohazardous, genetically amendable with small genomes that permit genome-wide analysis of virologic and cellular functions. In this review, similarities and differences of these two yeasts are described. Studies of virologic activities such as viral translation, viral replication and genome-wide study of virus-cell interactions in yeasts are highlighted. Impacts of viral proteins on basic cellular functions such as cell cycle regulation and programed cell death are discussed. Potential applications of using yeasts as hosts to carry out functional analysis of small viral genome and to develop high throughput drug screening platform for the discovery of antiviral drugs are presented. PMID:29082230

  12. Antibiotic treatment attenuates behavioral and neurochemical changes induced by exposure of rats to group a streptococcal antigen.

    Directory of Open Access Journals (Sweden)

    Dafna Lotan

    Full Text Available Post-streptococcal A (GAS sequelae including movement and neuropsychiatric disorders have been associated with improvement in response to antibiotic therapy. Besides eradication of infection, the underlying basis of attenuation of neuropsychiatric symptoms following antibiotic treatment is not known. The aim of the present study was to test the efficacy of antibiotic treatment in a rat model of GAS-related neuropsychiatric disorders. In the model, rats were not infected but were exposed to GAS-antigen or to adjuvants only (Control rats and treated continuously with the antibiotic ampicillin in their drinking water from the first day of GAS-antigen exposure. Two additional groups of rats (GAS and Control did not receive ampicillin in their drinking water. Behavior of the four groups was assessed in the forced swim, marble burying and food manipulation assays. We assessed levels of D1 and D2 dopamine receptors and tyrosine hydroxylase in the prefrontal cortex and striatum, and IgG deposition in the prefrontal cortex, striatum and thalamus. Ampicillin treatment prevented emergence of the motor and some of the behavioral alterations induced by GAS-antigen exposure, reduced IgG deposition in the thalamus of GAS-exposed rats, and tended to attenuate the increase in the level of TH and D1 and D2 receptors in their striatum, without concomitantly reducing the level of sera anti-GAS antibodies. Our results reinforce the link between exposure to GAS antigen, dysfunction of central dopaminergic pathways and motor and behavioral alterations. Our data further show that some of these deleterious effects can be attenuated by antibiotic treatment, and supports the latter's possible efficacy as a prophylactic treatment in GAS-related neuropsychiatric disorders.

  13. Immunization with FSHβ fusion protein antigen prevents bone loss in a rat ovariectomy-induced osteoporosis model

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Wenxin; Yan, Xingrong; Du, Huicong; Cui, Jihong; Li, Liwen, E-mail: liven@nwu.edu.cn; Chen, Fulin, E-mail: chenfl@nwu.edu.cn

    2013-05-03

    Highlights: •A GST-FSH fusion protein was successfully expressed in E. coli. •Immunization with GST-FSH antigen can raise high-titer anti-FSH polyclonal sera. •Anti-FSH polyclonal sera can neutralize osteoclastogenic effect of FSH in vitro. •FSH immunization can prevent bone loss in a rat osteoporosis model. -- Abstract: Osteoporosis, a metabolic bone disease, threatens postmenopausal women globally. Hormone replacement therapy (HTR), especially estrogen replacement therapy (ERT), is used widely in the clinic because it has been generally accepted that postmenopausal osteoporosis is caused by estrogen deficiency. However, hypogonadal α and β estrogen receptor null mice were only mildly osteopenic, and mice with either receptor deleted had normal bone mass, indicating that estrogen may not be the only mediator that induces osteoporosis. Recently, follicle-stimulating hormone (FSH), the serum concentration of which increases from the very beginning of menopause, has been found to play a key role in postmenopausal osteoporosis by promoting osteoclastogenesis. In this article, we confirmed that exogenous FSH can enhance osteoclast differentiation in vitro and that this effect can be neutralized by either an anti-FSH monoclonal antibody or anti-FSH polyclonal sera raised by immunizing animals with a recombinant GST-FSHβ fusion protein antigen. Moreover, immunizing ovariectomized rats with the GST-FSHβ antigen does significantly prevent trabecular bone loss and thereby enhance the bone strength, indicating that a FSH-based vaccine may be a promising therapeutic strategy to slow down bone loss in postmenopausal women.

  14. Improved Activation toward Primary Colorectal Cancer Cells by Antigen-Specific Targeting Autologous Cytokine-Induced Killer Cells

    Directory of Open Access Journals (Sweden)

    Claudia Schlimper

    2012-01-01

    Full Text Available Adoptive therapy of malignant diseases with cytokine-induced killer (CIK cells showed promise in a number of trials; the activation of CIK cells from cancer patients towards their autologous cancer cells still needs to be improved. Here, we generated CIK cells ex vivo from blood lymphocytes of colorectal cancer patients and engineered those cells with a chimeric antigen receptor (CAR with an antibody-defined specificity for carcinoembryonic antigen (CEA. CIK cells thereby gained a new specificity as defined by the CAR and showed increase in activation towards CEA+ colon carcinoma cells, but less in presence of CEA− cells, indicated by increased secretion of proinflammatory cytokines. Redirected CIK activation was superior by CAR-mediated CD28-CD3ζ than CD3ζ signaling only. CAR-engineered CIK cells from colon carcinoma patients showed improved activation against their autologous, primary carcinoma cells from biopsies resulting in more efficient tumour cell lysis. We assume that adoptive therapy with CAR-modified CIK cells shows improved selectivity in targeting autologous tumour lesions.

  15. How does yeast respond to pressure?

    Directory of Open Access Journals (Sweden)

    Fernandes P.M.B.

    2005-01-01

    Full Text Available The brewing and baking yeast Saccharomyces cerevisiae has been used as a model for stress response studies of eukaryotic cells. In this review we focus on the effect of high hydrostatic pressure (HHP on S. cerevisiae. HHP exerts a broad effect on yeast cells characteristic of common stresses, mainly associated with protein alteration and lipid bilayer phase transition. Like most stresses, pressure induces cell cycle arrest. Below 50 MPa (500 atm yeast cell morphology is unaffected whereas above 220 MPa wild-type cells are killed. S. cerevisiae cells can acquire barotolerance if they are pretreated with a sublethal stress due to temperature, ethanol, hydrogen peroxide, or pressure. Nevertheless, pressure only leads to protection against severe stress if, after pressure pretreatment, the cells are also re-incubated at room pressure. We attribute this effect to the inhibition of the protein synthesis apparatus under HHP. The global genome expression analysis of S. cerevisiae cells submitted to HHP revealed a stress response profile. The majority of the up-regulated genes are involved in stress defense and carbohydrate metabolism while most repressed genes belong to the cell cycle progression and protein synthesis categories. However, the signaling pathway involved in the pressure response is still to be elucidated. Nitric oxide, a signaling molecule involved in the regulation of a large number of cellular functions, confers baroprotection. Furthermore, S. cerevisiae cells in the early exponential phase submitted to 50-MPa pressure show induction of the expression level of the nitric oxide synthase inducible isoform. As pressure becomes an important biotechnological tool, studies concerning this kind of stress in microorganisms are imperative.

  16. 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.

  17. L-arabinose fermenting yeast

    Science.gov (United States)

    Zhang, Min; Singh, Arjun; Suominen, Pirkko; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric

    2013-02-12

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

  18. Resveratrol suppresses ethanol stress in winery and bottom brewery yeast by affecting superoxide dismutase, lipid peroxidation and fatty acid profile.

    Science.gov (United States)

    Gharwalova, Lucia; Sigler, Karel; Dolezalova, Jana; Masak, Jan; Rezanka, Tomas; Kolouchova, Irena

    2017-11-03

    Mid-exponential cultures of two traditional biotechnological yeast species, winery Saccharomyces cerevisiae and the less ethanol tolerant bottom-fermenting brewery Saccharomyces pastorianus, were exposed to different concentrations of added ethanol (3, 5 and 8%) The degree of ethanol-induced cell stress was assessed by measuring the cellular activity of superoxide dismutase (SOD), level of lipid peroxidation products, changes in cell lipid content and fatty acid profile. The resveratrol as an antioxidant was found to decrease the ethanol-induced rise of SOD activity and suppress the ethanol-induced decrease in cell lipids. A lower resveratrol concentration (0.5 mg/l) even reduced the extent of lipid peroxidation in cells. Resveratrol also alleviated ethanol-induced changes in cell lipid composition in both species by strongly enhancing the proportion of saturated fatty acids and contributing thereby to membrane stabilization. Lower resveratrol concentrations could thus diminish the negative effects of ethanol stress on yeast cells and improve their physiological state. These effects may be utilized to enhance yeast vitality in high-ethanol-producing fermentations or to increase the number of yeast generations in brewery.

  19. Protracted outbreak of severe delta hepatitis: experience in an isolated Amerindian population of the Upper Orinoco basin.

    Science.gov (United States)

    Torres, J R; Mondolfi, A

    1991-01-01

    In an investigation of a 21-year-old epidemic of severe hepatitis, 80 serum samples were studied from two isolated Yanomami Amerindian populations of the Upper Orinoco basin in Venezuela. Of the assayed samples, 30.6% were positive for hepatitis B surface antigen (HBsAg), 53.7% were considered to reflect immunity to infection with hepatitis B virus (HBV), and only 16.2% were believed to reflect susceptibility to HBV infection; 82.5% of the samples tested positive for any marker of HBV infection. Thirty-one (39.7%) of 78 samples were also positive for antibody to delta antigen, including 91.6% of those positive for HBsAg and 20.9% of those immune to HBV. Our findings provide evidence of a high prevalence of HBV infection in this population. Furthermore, the high prevalence of antibody to delta antigen strongly suggests that coinfections with HBV or superinfections with hepatitis delta virus (HDV) in HBV carriers may be an important factor in the occurrence of an unusually high number of cases of fulminant hepatitis and of chronic liver disease. Serum samples obtained at the beginning of the outbreak 13 years earlier from 36 selected cases in the same population revealed a high rate of HBV infection (96.5%). All six HBsAg carriers from whom enough serum remained to be assayed were positive for antibody to delta antigen. Our findings indicate that the outbreak coincided with the introduction of HDV into a population with an already-high prevalence of HBV infection.

  20. Yeast Methylotrophy and Autophagy in a Methanol-Oscillating Environment on Growing Arabidopsis thaliana Leaves

    Science.gov (United States)

    Kawaguchi, Kosuke; Yurimoto, Hiroya; Oku, Masahide; Sakai, Yasuyoshi

    2011-01-01

    The yeast Candida boidinii capable of growth on methanol proliferates and survives on the leaves of Arabidopsis thaliana. The local methanol concentration at the phyllosphere of growing A. thaliana exhibited daily periodicity, and yeast cells responded by altering both the expression of methanol-inducible genes and peroxisome proliferation. Even under these dynamically changing environmental conditions, yeast cells proliferated 3 to 4 times in 11 days. Among the C1-metabolic enzymes, enzymes in the methanol assimilation pathway, but not formaldehyde dissimilation or anti-oxidizing enzymes, were necessary for yeast proliferation at the phyllosphere. Furthermore, both peroxisome assembly and pexophagy, a selective autophagy pathway that degrades peroxisomes, were necessary for phyllospheric proliferation. Thus, the present study sheds light on the life cycle and physiology of yeast in the natural environment at both the molecular and cellular levels. PMID:21966472

  1. Infection with hepatitis B and hepatitis C virus as risk factors for hepatocarcinoma in Peru: Study of cases and control; Infeccion con virus de la hepatitis B y hepatitis C como factores de riesgo para hepatocarcinoma en el Peru: estudio de casos y controles

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, E; Celis, J; Pizarro, R; Montalbeti, J; Urbano, R [Instituto de Enfermedades Neoplasicas, Lima (Peru); Almonte, M [Centro de Investigacion en Cancer Maes Heller, Lima (Peru)

    1998-09-01

    To investigate whether past exposure to Hepatitis B virus (HBV) and Hepatitis C Virus (HCV) were risk factors for the development of Hepatocellular Carcinoma (HCC) in Peru, a case-control study of 136 patients with HCC and 136 age-matched and sex-matched control subjects was performed. Past exposure to HBV and HCV were assessed respectively by antibody to hepatitis B core antigen (Anti-HBc) and HbsAg and Anti-HCV. Of the HCC cases, 63,2% were positive for HbsAg and 0,73% for anti-HCV. Of the control patients, 4,4% were positive to HbsAg and 0,73% to anti-HCV. The mean age of patients with HCC negative for HbsAg was significantly greater than that of patients HCC positive for HbsAg (35,4 versus 29,4 years, p less than 0,001). The HbsAg patients are 36,26 times more prone to developing HCC than those with HbsAg negative (95% confidence interval: 15.31-90.7). Infection with HCV does not pose a risk for the development of HCC (RR 1, 95% confidence interval: 0.062-16.152). A causal relation between HBV infection in children HCC was observed. These results indicate that HbsAg carriage is a risk factor for HCC in Peru. The importance of vertical or perinatal transmission of HBV and the prophylactic role of passive immunization plus vaccination during childhood is emphasized as well as the selective vaccination of high risk groups. (authors)

  2. Infection with hepatitis B and hepatitis C virus as risk factors for hepatocarcinoma in Peru: Study of cases and control

    International Nuclear Information System (INIS)

    Ruiz, E.; Celis, J.; Pizarro, R.; Montalbeti, J.; Urbano, R.; Almonte, M.

    1998-01-01

    To investigate whether past exposure to Hepatitis B virus (HBV) and Hepatitis C Virus (HCV) were risk factors for the development of Hepatocellular Carcinoma (HCC) in Peru, a case-control study of 136 patients with HCC and 136 age-matched and sex-matched control subjects was performed. Past exposure to HBV and HCV were assessed respectively by antibody to hepatitis B core antigen (Anti-HBc) and HbsAg and Anti-HCV. Of the HCC cases, 63,2% were positive for HbsAg and 0,73% for anti-HCV. Of the control patients, 4,4% were positive to HbsAg and 0,73% to anti-HCV. The mean age of patients with HCC negative for HbsAg was significantly greater than that of patients HCC positive for HbsAg (35,4 versus 29,4 years, p less than 0,001). The HbsAg patients are 36,26 times more prone to developing HCC than those with HbsAg negative (95% confidence interval: 15.31-90.7). Infection with HCV does not pose a risk for the development of HCC (RR 1, 95% confidence interval: 0.062-16.152). A causal relation between HBV infection in children HCC was observed. These results indicate that HbsAg carriage is a risk factor for HCC in Peru. The importance of vertical or perinatal transmission of HBV and the prophylactic role of passive immunization plus vaccination during childhood is emphasized as well as the selective vaccination of high risk groups. (authors)

  3. 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

  4. 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)

  5. Targeted gene delivery to the synovial pannus in antigen-induced arthritis by ultrasound-targeted microbubble destruction in vivo.

    Science.gov (United States)

    Xiang, Xi; Tang, Yuanjiao; Leng, Qianying; Zhang, Lingyan; Qiu, Li

    2016-02-01

    The purpose of this study was to optimize an ultrasound-targeted microbubble destruction (UTMD) technique to improve the in vivo transfection efficiency of the gene encoding enhanced green fluorescent protein (EGFP) in the synovial pannus in an antigen-induced arthritis rabbit model. A mixture of microbubbles and plasmids was locally injected into the knee joints of an antigen-induced arthritis (AIA) rabbits. The plasmid concentrations and ultrasound conditions were varied in the experiments. We also tested local articular and intravenous injections. The rabbits were divided into five groups: (1) ultrasound+microbubbles+plasmid; (2) ultrasound+plasmid; (3) microbubble+plasmid; (4) plasmid only; (5) untreated controls. EGFP expression was observed by fluorescent microscope and immunohistochemical staining in the synovial pannus of each group. The optimal plasmid dosage and ultrasound parameter were determined based on the results of EGFP expression and the present and absent of tissue damage under light microscopy. The irradiation procedure was performed to observe the duration of the EGFP expression in the synovial pannus and other tissues and organs, as well as the damage to the normal cells. The optimal condition was determined to be a 1-MHz ultrasound pulse applied for 5 min with a power output of 2 W/cm(2) and a 20% duty cycle along with 300 μg of plasmid. Under these conditions, the synovial pannus showed significant EGFP expression without significant damage to the surrounding normal tissue. The EGFP expression induced by the local intra-articular injection was significantly more increased than that induced by the intravenous injection. The EGFP expression in the synovial pannus of the ultrasound+microbubbles+plasmid group was significantly higher than that of the other four groups (Ppannus of an AIA model. Thus, this could become a safe and effective non-viral gene transfection procedure for arthritis therapy. Copyright © 2015 Elsevier B.V. All rights

  6. Indole-3-Acetic Acid-Producing Yeasts in the Phyllosphere of the Carnivorous Plant Drosera indica L

    Science.gov (United States)

    Shin, Li-Ying; Wei, Jyuan-Yu; Fu, Shih-Feng; Chou, Jui-Yu

    2014-01-01

    Yeasts are widely distributed in nature and exist in association with other microorganisms as normal inhabitants of soil, vegetation, and aqueous environments. In this study, 12 yeast strains were enriched and isolated from leaf samples of the carnivorous plant Drosera indica L., which is currently threatened because of restricted habitats and use in herbal industries. According to similarities in large subunit and small subunit ribosomal RNA gene sequences, we identified 2 yeast species in 2 genera of the phylum Ascomycota, and 5 yeast species in 5 genera of the phylum Basidiomycota. All of the isolated yeasts produced indole-3-acetic acid (IAA) when cultivated in YPD broth supplemented with 0.1% L-tryptophan. Growth conditions, such as the pH and temperature of the medium, influenced yeast IAA production. Our results also suggested the existence of a tryptophan-independent IAA biosynthetic pathway. We evaluated the effects of various concentrations of exogenous IAA on yeast growth and observed that IAA produced by wild yeasts modifies auxin-inducible gene expression in Arabidopsis. Our data suggest that yeasts can promote plant growth and support ongoing prospecting of yeast strains for inclusion into biofertilizer for sustainable agriculture. PMID:25464336

  7. How a Small Family of Yeast IDPs Control Complicated Processes Related to DNA Replication

    DEFF Research Database (Denmark)

    Marabini, Riccardo

    Ribonucleotide reductase (RNR) and proliferating cell nuclear antigen (PCNA) are two essential proteins involved in DNA replication. RNR catalyzes the last and rate limiting step of the deoxyribonucleotide biosynthetic pathway. The dysregulation of RNR has been related to higher mutation rate...... characterized in budding and fission yeast. Within this protein family Dif1 (from S. cerevisiae) and Spd1 (from S. pombe) were analyzed in this study. These proteins were previously found to interact with and regulate the activity of RNR and Spd1 was also linked to PCNA dependent signaling for degradation...

  8. Yeast caspase-dependent apoptosis in Saccharomyces cerevisiae BY4742 induced by antifungal and potential antitumor agent clotrimazole.

    Science.gov (United States)

    Kavakçıoğlu, Berna; Tarhan, Leman

    2018-01-01

    Clotrimazole is an antifungal medication commonly used in the treatment of fungal infections. There is also promising research on using clotrimazole against other diseases such as malaria, beriberi, tineapedis and cancer. It was aimed to investigate the apoptotic phenotype in Saccharomyces cerevisiae induced by clotrimazole. The exposure of S. cerevisiae to 10 µM clotrimazole for 3, 6 and 9 h caused to decrease in cell viability by 24.82 ± 0.81, 56.00 ± 1.54 and 77.59 ± 0.53%, respectively. It was shown by Annexin V-PI assay that 110 µM clotrimazole treatment caused to death by 35.5 ± 2.48% apoptotic and only 13.1 ± 0.08% necrotic pathway within 30 min. The occurrence of DNA strand breaks and condensation could be visualised by the TUNEL and DAPI stainings, respectively. Yeast caspase activity was induced 12.34 ± 0.71-fold after 110 µM clotrimazole treatment for 30 min compared to the control. The dependency of clotrimazole-induced apoptosis to caspase was also shown using Δyca1 mutant.

  9. [Mutants of the yeast Saccharomyces cerevisiae characterized by enhanced induced mutagenesis. III. Effect of the him mutation on the effectiveness and specificity of UF-induced mutagenesis].

    Science.gov (United States)

    Ivanov, E L; Koval'tsova, S V; Korolev, V G

    1987-09-01

    We have studied the influence of him1-1, him2-1, him3-1 and himX mutations on induction frequency and specificity of UV-induced adenine-dependent mutations in the yeast Saccharomyces cerevisiae. Him mutations do not render haploid cells more sensitive to the lethal action of UV-light; however, in him strains adenine-dependent mutations (ade1, ade2) were induced more frequently (1.5--2-fold), as compared to the HIM strain. An analysis of the molecular nature of ade2 mutants revealed that him1-1, him2-1 and himX mutations increase specifically the yield of transitions (AT----GC and GC----AT), whereas in the him3-1 strain the yield of transversions was enhanced as well. We suggest him mutations analysed to affect specific repair pathway for mismatch correction.

  10. Twenty-Year Evolution of Hepatitis B Virus and Human Immunodeficiency Virus Prevalence and Incidence in Voluntary Blood Donors in Côte d'Ivoire.

    Science.gov (United States)

    Seri, Benjamin; Minga, Albert; Gabillard, Delphine; Dembele, Bamori; Konate, Seidou; Le Carrou, Jérôme; Dohoun, Lambert; Abo, Yao; Karcher, Sophie; Coffie, Patrick; N'Dri-Yoman, Thérèse; Attia, Alain; Eholié, Serge P; Danel, Christine; Lacombe, Karine; Anglaret, Xavier; Boyd, Anders

    2018-04-01

    Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) share common risk factors. The parallel description of their frequency over time may help capture their similarities and differences. Using data from the National Transfusion Center of Abidjan, we estimated the following over a 20-year period: (1) the prevalence of HIV and hepatitis B surface antigen (HBsAg) positivity at first contact; and (2) the incidence of HIV and HBsAg seroconversion in negative first-time blood donors. Between 1992 and 2012, 422319 donors (men [M] = 74%) provided 1063825 blood donations. For first-time donors, HIV prevalence decreased from 7.1% (M = 5.9%, women [W] =11.0%) in 1992-1994 to 1.1% (M = 0.8%, W = 2.0%) in 2010-2012. Prevalence of HBsAg positivity remained stable at 10.8% (M = 11.7%, W = 7.3%) in 1992-1994 to 11.1% (M = 12.5%, W = 7.1%) in 2010-2012. Among regular donors (N = 129256), the incidence of becoming HIV or HBsAg positive, respectively, decreased from 4.9 per 100 (M = 4.5, W = 8.6) and 7.3 per 100 person-years (M = 7.8, W = 2.3) in 1992-1994 to 0.07 (M = 0.06, W = 0.11) and 0.2 per 100 person-years (M = 0.2, W = 0.2) in 2010-2012. Human immunodeficiency virus prevalence and incidence decreased dramatically over time, whereas HBV prevalence remained stable. Incidence of HBsAg seroconversion, although decreasing, still reached unexpected levels, suggesting that the risk of HBV infection in adults may be higher than expected. Hepatitis B surface antigen-negative blood-donors should be offered HBV vaccination.

  11. 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

  12. 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.

  13. Induction of respiratory deficiency in yeast by manganese, copper, cobalt and nickel

    Energy Technology Data Exchange (ETDEWEB)

    Lindegren, C C; Nagai, S; Nagai, H

    1958-08-16

    Among the chemical agents which induce respiratory deficiency in yeasts, acriflavine, triphenyl tetrazolium chloride, p-nitrophenol, and propamidine isethionate are especially effective in producing the deficiency in a large fraction of the surviving population. The present work is a survey of the efficacy of various metallic salts in inducing respiratory deficiency.

  14. Inhibition effects of {sup 125}I-triplex forming oligonucleotide to hepatoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhongwei, Lv; Min, Hou; Haidong, Cai; Xueyu, Yuan; Yuehua, Yang; Shidong, Yuan [Department of Nuclear Medicine, 10th People' s Hospital, Tongji Univ., Shanghai (China); Junmin, He

    2007-08-15

    Objective: Triplex forming oligonucleotide (TFO) has been reported as a new antigene strategy. The purpose of this study was to observe the inhibition effects of {sup 125}I-TFO on hepatoma cells and to investigate the possibility of using {sup 125}I-TFO as an antigene radiotherapy technique for hepatocellular carcinoma (HCC) related to HBV. Methods: TFO complementary to the initiator of S gene of HBV was synthesized and labeled with {sup 125}I. HepG2.2.15 cells, in which HBV genome was integrated, were incubated with {sup 125}I-TFO, TFO and {sup 125}I respectively. After incubation, hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) of each group were assayed with ELISA and the survival rate of cells in each group was determined with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide (MTT) reduction assay. Results: {sup 125}I-TFO showed a high stability with a radiolabeling rate of >93%. The radiochemical purity of labeled compound was 90.8%, 81.1% and 73.2% respectively after 12, 48 and 72 h at 37 degree C. The peak inhibition effect of {sup 125}I-TFO on synthesizing HBsAg and HBeAg by HepG2.2.15 cells were found at 48 h after transfection, with significantly the highest inhibition rate of 45.2% for HBsAg and 74.5% for HBeAg expression among the three groups(P<0.01 ). As the transfection time prolonged its inhibition effects were stronger. Conclusion: {sup 125}I-TFO may inhibit the antigen expression of HBV and the growth of hepatocarcinoma cells, thus it may provide a new approach to develop gene-based radiotherapeutic pharmaceuticals for anti-HBV and HCC. (authors)

  15. Delayed radiation-induced inflammation accompanying a marked carbohydrate antigen 19-9 elevation in a patient with resected pancreatic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mattes, Malcolm D.; Cardinal, Jon S.; Jacobson, Geraldine M. [West Virginia University School of Medicine, Morgantown (United States)

    2016-06-15

    Although carbohydrate antigen (CA) 19-9 is a useful tumor marker for pancreatic cancer, it can also become elevated from a variety of benign and malignant conditions. Herein we describe an unusual presentation of elevated CA 19-9 in an asymptomatic patient who had previously undergone adjuvant chemotherapy and radiation therapy for resected early stage pancreatic cancer. The rise in CA 19-9 might be due to delayed radiation-induced inflammation related to previous intra-abdominal radiation therapy with or without radiation recall induced by gemcitabine. After treatment with corticosteroids the CA 19-9 level decreased to normal, and the patient has not developed any evidence of recurrent cancer to date.

  16. Yeast Flocculation—Sedimentation and Flotation

    Directory of Open Access Journals (Sweden)

    Graham G. Stewart

    2018-04-01

    Full Text Available Unlike most fermentation alcohol beverage production processes, brewers recycle their yeast. This is achieved by employing a yeast culture’s: flocculation, adhesion, sedimentation, flotation, and cropping characteristics. As a consequence of yeast recycling, the quality of the cropped yeast culture’s characteristics is critical. However, the other major function of brewer’s yeast is to metabolise wort into ethanol, carbon dioxide, glycerol, and other fermentation products, many of which contribute to beer’s overall flavour characteristics. This review will only focus on brewer’s yeast flocculation characteristics.

  17. Investigating temporal changes in the yeast phosphoproteome upon fatty acid starvation

    DEFF Research Database (Denmark)

    Pultz, Dennis; Bennetzen, Martin; Andersen, Jens S.

    2011-01-01

    under nutrition but not malnutrition extends the life span of multiple species, ranging from single-celled organisms like yeast to mammals. This increase in longevity by dietary restriction (DR) is coupled to profound beneficial effects on age-related pathology. Despite the number of studies on DR......Investigating stemporal changes in the yeast phosphoproteome upon fatty acid starvation Dennis Pultz*, Martin Bennetzen*, Jens S. Andersen and Nils J.Færgeman. Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark, 5230 Reducing food intake to induce...... and the physiological changes DR induces, only little is known about the genetics and signalling networks which regulate the DR response. We have recently shown that inhibition of fatty acid synthesis in Saccharomyces cerevisiae results in a dependency on autophagy in maintaining normal life span. We further believe...

  18. Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts.

    Science.gov (United States)

    Palková, Zdena; Váchová, Libuše

    2016-09-01

    Yeasts, historically considered to be single-cell organisms, are able to activate different differentiation processes. Individual yeast cells can change their life-styles by processes of phenotypic switching such as the switch from yeast-shaped cells to filamentous cells (pseudohyphae or true hyphae) and the transition among opaque, white and gray cell-types. Yeasts can also create organized multicellular structures such as colonies and biofilms, and the latter are often observed as contaminants on surfaces in industry and medical care and are formed during infections of the human body. Multicellular structures are formed mostly of stationary-phase or slow-growing cells that diversify into specific cell subpopulations that have unique metabolic properties and can fulfill specific tasks. In addition to the development of multiple protective mechanisms, processes of metabolic reprogramming that reflect a changed environment help differentiated individual cells and/or community cell constituents to survive harmful environmental attacks and/or to escape the host immune system. This review aims to provide an overview of differentiation processes so far identified in individual yeast cells as well as in multicellular communities of yeast pathogens of the Candida and Cryptococcus spp. and the Candida albicans close relative, Saccharomyces cerevisiae. Molecular mechanisms and extracellular signals potentially involved in differentiation processes are also briefly mentioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. L-arabinose fermenting yeast

    Science.gov (United States)

    Zhang, Min; Singh, Arjun; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric; Suominen, Pirkko

    2010-12-07

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. Methods of producing ethanol include utilizing these modified yeast strains. ##STR00001##

  20. Nitrile Metabolizing Yeasts

    Science.gov (United States)

    Bhalla, Tek Chand; Sharma, Monica; Sharma, Nitya Nand

    Nitriles and amides are widely distributed in the biotic and abiotic components of our ecosystem. Nitrile form an important group of organic compounds which find their applications in the synthesis of a large number of compounds used as/in pharmaceutical, cosmetics, plastics, dyes, etc>. Nitriles are mainly hydro-lyzed to corresponding amide/acid in organic chemistry. Industrial and agricultural activities have also lead to release of nitriles and amides into the environment and some of them pose threat to human health. Biocatalysis and biotransformations are increasingly replacing chemical routes of synthesis in organic chemistry as a part of ‘green chemistry’. Nitrile metabolizing organisms or enzymes thus has assumed greater significance in all these years to convert nitriles to amides/ acids. The nitrile metabolizing enzymes are widely present in bacteria, fungi and yeasts. Yeasts metabolize nitriles through nitrilase and/or nitrile hydratase and amidase enzymes. Only few yeasts have been reported to possess aldoxime dehydratase. More than sixty nitrile metabolizing yeast strains have been hither to isolated from cyanide treatment bioreactor, fermented foods and soil. Most of the yeasts contain nitrile hydratase-amidase system for metabolizing nitriles. Transformations of nitriles to amides/acids have been carried out with free and immobilized yeast cells. The nitrilases of Torulopsis candida>and Exophiala oligosperma>R1 are enantioselec-tive and regiospecific respectively. Geotrichum>sp. JR1 grows in the presence of 2M acetonitrile and may have potential for application in bioremediation of nitrile contaminated soil/water. The nitrilase of E. oligosperma>R1 being active at low pH (3-6) has shown promise for the hydroxy acids. Immobilized yeast cells hydrolyze some additional nitriles in comparison to free cells. It is expected that more focus in future will be on purification, characterization, cloning, expression and immobilization of nitrile metabolizing

  1. Proteolytic activities in yeast after UV irradiation. Pt. 1

    International Nuclear Information System (INIS)

    Schwencke, J.; Moustacchi, E.

    1982-01-01

    Specific proteolytic activities are known to be induced in Escherichia coli following irradiation. Consequently it seemed of interest to investigate whether variations in proteinase activities occur in yeast. Among the five most well known proteinases of Saccharomyces cerevisiae, we have found that proteinase B activity increases up to three times in wild-type RAD + yeast cells after a dose of 50 Jm -2 of 254 nm ultraviolet light (40% survival). Carboxypeptidase Y and aminopeptidase I (leucin aminopeptidase) activities were only moderately increased. Proteinase A activity was only slightly enhanced, while aminopeptidase II (lysin aminopeptidase) was unaffected in both RAD + strains studied. The observed post UV-increase in proteinase B activity was inhibited by cycloheximide and was dose dependent. Increases in proteinase B levels were independent of the activation method used to destroy the proteinase B-inhibitor complex present in the crude yeast extracts. A standard method for comparison of the postirradiation levels among different proteinases, strains and methods of activation is presented. (orig.)

  2. Proteolytic activities in yeast after UV irradiation. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Schwencke, J.; Moustacchi, E.

    1982-04-01

    Specific proteolytic activities are known to be induced in Escherichia coli following irradiation. Consequently it seemed of interest to investigate whether variations in proteinase activities occur in yeast. Among the five most well known proteinases of Saccharomyces cerevisiae, we have found that proteinase B activity increases up to three times in wild-type RAD/sup +/ yeast cells after a dose of 50 Jm/sup -2/ of 254 nm ultraviolet light (40% survival). Carboxypeptidase Y and aminopeptidase I (leucin aminopeptidase) activities were only moderately increased. Proteinase A activity was only slightly enhanced, while aminopeptidase II (lysin aminopeptidase) was unaffected in both RAD/sup +/ strains studied. The observed post UV-increase in proteinase B activity was inhibited by cycloheximide and was dose dependent. Increases in proteinase B levels were independent of the activation method used to destroy the proteinase B-inhibitor complex present in the crude yeast extracts. A standard method for comparison of the postirradiation levels among different proteinases, strains and methods of activation is presented.

  3. A yeast-based assay identifies drugs that interfere with immune evasion of the Epstein-Barr virus

    Directory of Open Access Journals (Sweden)

    Cécile Voisset

    2014-04-01

    Full Text Available Epstein-Barr virus (EBV is tightly associated with certain human cancers, but there is as yet no specific treatment against EBV-related diseases. The EBV-encoded EBNA1 protein is essential to maintain viral episomes and for viral persistence. As such, EBNA1 is expressed in all EBV-infected cells, and is highly antigenic. All infected individuals, including individuals with cancer, have CD8+ T cells directed towards EBNA1 epitopes, yet the immune system fails to detect and destroy cells harboring the virus. EBV immune evasion depends on the capacity of the Gly-Ala repeat (GAr domain of EBNA1 to inhibit the translation of its own mRNA in cis, thereby limiting the production of EBNA1-derived antigenic peptides presented by the major histocompatibility complex (MHC class I pathway. Here we establish a yeast-based assay for monitoring GAr-dependent inhibition of translation. Using this assay we identify doxorubicin (DXR as a compound that specifically interferes with the GAr effect on translation in yeast. DXR targets the topoisomerase-II–DNA complexes and thereby causes genomic damage. We show, however, that the genotoxic effect of DXR and various analogs thereof is uncoupled from the effect on GAr-mediated translation control. This is further supported by the observation that etoposide and teniposide, representing another class of topoisomerase-II–DNA targeting drugs, have no effect on GAr-mediated translation control. DXR and active analogs stimulate, in a GAr-dependent manner, EBNA1 expression in mammalian cells and overcome GAr-dependent restriction of MHC class I antigen presentation. These results validate our approach as an effective high-throughput screening assay to identify drugs that interfere with EBV immune evasion and, thus, constitute candidates for treating EBV-related diseases, in particular EBV-associated cancers.

  4. A yeast-based assay identifies drugs that interfere with immune evasion of the Epstein-Barr virus.

    Science.gov (United States)

    Voisset, Cécile; Daskalogianni, Chrysoula; Contesse, Marie-Astrid; Mazars, Anne; Arbach, Hratch; Le Cann, Marie; Soubigou, Flavie; Apcher, Sébastien; Fåhraeus, Robin; Blondel, Marc

    2014-04-01

    Epstein-Barr virus (EBV) is tightly associated with certain human cancers, but there is as yet no specific treatment against EBV-related diseases. The EBV-encoded EBNA1 protein is essential to maintain viral episomes and for viral persistence. As such, EBNA1 is expressed in all EBV-infected cells, and is highly antigenic. All infected individuals, including individuals with cancer, have CD8(+) T cells directed towards EBNA1 epitopes, yet the immune system fails to detect and destroy cells harboring the virus. EBV immune evasion depends on the capacity of the Gly-Ala repeat (GAr) domain of EBNA1 to inhibit the translation of its own mRNA in cis, thereby limiting the production of EBNA1-derived antigenic peptides presented by the major histocompatibility complex (MHC) class I pathway. Here we establish a yeast-based assay for monitoring GAr-dependent inhibition of translation. Using this assay we identify doxorubicin (DXR) as a compound that specifically interferes with the GAr effect on translation in yeast. DXR targets the topoisomerase-II-DNA complexes and thereby causes genomic damage. We show, however, that the genotoxic effect of DXR and various analogs thereof is uncoupled from the effect on GAr-mediated translation control. This is further supported by the observation that etoposide and teniposide, representing another class of topoisomerase-II-DNA targeting drugs, have no effect on GAr-mediated translation control. DXR and active analogs stimulate, in a GAr-dependent manner, EBNA1 expression in mammalian cells and overcome GAr-dependent restriction of MHC class I antigen presentation. These results validate our approach as an effective high-throughput screening assay to identify drugs that interfere with EBV immune evasion and, thus, constitute candidates for treating EBV-related diseases, in particular EBV-associated cancers.

  5. Sero‑prevalence of Hepatitis B Virus Infection and its Risk factors ...

    African Journals Online (AJOL)

    with the exception of Morocco and Tunisia, which have intermediate endemicity. ... tested for hepatitis B e antigen (HBeAg) using ELISA kits (Orgenics, Israel). A pretested ..... Table 3: Prevalence of HBsAg in relation to sociodemographic.

  6. Intensification of the process of sorption of copper ions by yeast of Saccharomyces cerevisiae 1968 by means of a permanent magnetic field

    International Nuclear Information System (INIS)

    Gorobets, Svetlana; Gorobets, Oksana; Ukrainetz, Anatoliy; Kasatkina, Taisiya; Goyko, Irina

    2004-01-01

    Possibility to replace mechanical stirring by magnetic field-induced one was shown for intensification of yeast biosorption and cementation. Combined method of metal ion recover, including Cu ion sorption by yeast Saccharomyces cerevisiae and Cu cementation on a surface of a steel matrix, is tested in a case of magnetic field-induced stirring

  7. Efficient Capsid Antigen Presentation From Adeno-Associated Virus Empty Virions In Vivo.

    Science.gov (United States)

    Pei, Xiaolei; Earley, Lauriel Freya; He, Yi; Chen, Xiaojing; Hall, Nikita Elexa; Samulski, Richard Jude; Li, Chengwen

    2018-01-01

    Adeno-associated virus (AAV) vectors have been successfully applied in clinical trials for hemophilic patients. Although promising, the clinical results suggest that the capsid-specific CD8+T cell response has a negative effect on therapeutic success. In an in vitro analysis using an engineered AAV virus carrying immune-dominant SIINFEKL peptide in the capsid backbone, we have previously demonstrated that capsid antigen presentation from full (genome containing) AAV capsids requires endosome escape and is proteasome dependent and that no capsid antigen presentation is induced from empty virions. In the present study, we examined capsid antigen presentation from administration of empty virions in animal models. In wild-type mice, similar to AAV full particles, capsid antigen presentation from AAV empty virion infection was dose dependent, and the kinetics studies showed that antigen presentation was detected from 2 to 40 days after AAV empty virion administration. In the transporter associated with antigen processing 1 deficient (TAP-/-) mice, capsid antigen presentation was inhibited from both AAV full and empty virions, but higher inhibition was achieved from AAV full particle administration than that from empty virions. This indicates that the pathway of capsid antigen presentation from AAV transduction is dependent on proteasome-mediated degradation of AAV capsids (mainly for full particles) and that the endosomal pathway may also play a role in antigen presentation from empty particles but not full virions. The capsid antigen presentation efficiency from AAV preparations was positively correlated with the amount of empty virions contaminated with full particles. Collectively, the results indicate that contamination of AAV empty virions induces efficient antigen presentation in vivo and the mechanism of capsid antigen presentation from empty virions involves both endosomal and proteasomal pathways. The elucidation of capsid antigen presentation from AAV empty

  8. Nuclear antigen expression by ultraviolet light irradiation - a contribution to the UV-induced autoimmunity

    Energy Technology Data Exchange (ETDEWEB)

    Wollina, U

    1986-05-01

    A review is given of nuclear antigen expression due to UVB, UVA, and PUVA. UVB alters DNA resulting in strong immunogenic UVDNA and complementary antibodies. Antibodies to UVDNA cross react with double-stranded DNA. UVDNA plays a (hypothetical) role in the induction of cutaneous lesions in lupus erythematosus (LE). Investigations of SS-A/Ro expression due to UVB seem to be more important under this view. Antibodies against SS-A/Ro are related to an increased photosensitivity in LE. PUVA and UVA are able to induce antinuclear antibodies of unknown specificity. It is likely that PUVA enhances SS-A/Ro expression in vitro. The results are discussed in sense of LE photobiology and unwanted side effects of photo(chemo)therapy in psoriasis. 54 references.

  9. Nuclear antigen expression by ultraviolet light irradiation - a contribution to the UV-induced autoimmunity

    International Nuclear Information System (INIS)

    Wollina, U.

    1986-01-01

    A review is given about nuclear antigen expression due to UVB, UVA, and PUVA. UVB alters DNA resulting in strong immunogenic UVDNA and complementary antibodies. Antibodies to UVDNA cross react with double-stranded DNA. UVDNA plays a (hypothetical) role in the induction of cutaneous lesions in lupus erythematosus (LE). Investigations about SS-A/Ro expression due to UVB seem to be more important under this view. Antibodies against SS-A/Ro are related to an increased photosensitivity in LE. PUVA and UVA are able to induce antinuclear antibodies of unknown specificity. It is likely that PUVA enhances SS-A/Ro expression in vitro. The results are discussed in sense of LE photobiology and unwanted side effects of photo(chemo)therapy in psoriasis. (author)

  10. Mycoplasma fermentans glycolipid-antigen as a pathogen of rheumatoid arthritis

    International Nuclear Information System (INIS)

    Kawahito, Yutaka; Ichinose, Sizuko; Sano, Hajime; Tsubouchi, Yasunori; Kohno, Masataka; Yoshikawa, Toshikazu; Tokunaga, Daisaku; Hojo, Tatsuya; Harasawa, Ryo; Nakano, Teruaki; Matsuda, Kazuhiro

    2008-01-01

    Mycoplasma fermentans has been suspected as one of the causative pathogenic microorganisms of rheumatoid arthritis (RA) however, the pathogenic mechanism is still unclear. We, previously, reported that glycolipid-antigens (GGPL-I and III) are the major antigens of M. fermentans. Monoclonal antibody against the GGPL-III could detect the existence of the GGPL-III antigens in synovial tissues from RA patients. GGPL-III antigens were detected in 38.1% (32/84) of RA patient's tissues, but not in osteoarthritis (OA) and normal synovial tissues. Immunoelectron microscopy revealed that a part of GGPL-III antigens are located at endoplasmic reticulum. GGPL-III significantly induced TNF-α and IL-6 production from peripheral blood mononulear cells, and also proliferation of synovial fibroblasts. Further study is necessary to prove that M. fermentans is a causative microorganism of RA; however, the new mechanisms of disease pathogenesis provides hope for the development of effective and safe immunotherapeutic strategies based on the lipid-antigen, GGPL-III, in the near future

  11. A radioimmunoassay to screen for antibodies to native conformational antigens and analyse ligand-induced structural states of antigenic proteins

    International Nuclear Information System (INIS)

    Bernotat-Danielowski, S.; Koepsell, H.

    1988-01-01

    A radioimmunoassay is described in which antigenic protein was immobilized by incubating nitrocellulose filters of defined diameter with antigen-containing solutions. Antigenic sites which are sensitive to protein denaturation by drying could be detected with the assay. The assay was also used to screen hybridoma supernatants for antibodies directed against Na + cotransport proteins from renal brush-border membranes. Monoclonal antibodies were selected which showed different binding charactertics depending on whether or not substrates of Na + cotransporters were present. One of the antibodies, which showed different antibody binding after addition of D-glucose or L-lactate, bound to a polypeptide component of the renal N + -D-glucose cotransporter and was able to inhibit Na + gradient-dependent. To investigate the effects of D-glucose and L-lactate on the binding of this antibody concentration dependence was measured. High and low affinity binding sites for D-glucose and L-lactate were characterized thereby demonstrating that the radioimmunoassay permits investigations of the properties of high and low affinity substrate binding sites. (author). refs.; 6 figs.; 2 tabs

  12. Drosophila Regulate Yeast Density and Increase Yeast Community Similarity in a Natural Substrate

    OpenAIRE

    Stamps, Judy A.; Yang, Louie H.; Morales, Vanessa M.; Boundy-Mills, Kyria L.

    2012-01-01

    Drosophila melanogaster adults and larvae, but especially larvae, had profound effects on the densities and community structure of yeasts that developed in banana fruits. Pieces of fruit exposed to adult female flies previously fed fly-conditioned bananas developed higher yeast densities than pieces of the same fruits that were not exposed to flies, supporting previous suggestions that adult Drosophila vector yeasts to new substrates. However, larvae alone had dramatic effects on yeast densit...

  13. Aspergillus antigen induces robust Th2 cytokine production, inflammation, airway hyperreactivity and fibrosis in the absence of MCP-1 or CCR2

    Directory of Open Access Journals (Sweden)

    Charo Israel F

    2004-09-01

    Full Text Available Abstract Background Asthma is characterized by type 2 T-helper cell (Th2 inflammation, goblet cell hyperplasia, airway hyperreactivity, and airway fibrosis. Monocyte chemoattractant protein-1 (MCP-1 or CCL2 and its receptor, CCR2, have been shown to play important roles in the development of Th2 inflammation. CCR2-deficient mice have been found to have altered inflammatory and physiologic responses in some models of experimental allergic asthma, but the role of CCR2 in contributing to inflammation and airway hyperreactivity appears to vary considerably between models. Furthermore, MCP-1-deficient mice have not previously been studied in models of experimental allergic asthma. Methods To test whether MCP-1 and CCR2 are each required for the development of experimental allergic asthma, we applied an Aspergillus antigen-induced model of Th2 cytokine-driven allergic asthma associated with airway fibrosis to mice deficient in either MCP-1 or CCR2. Previous studies with live Aspergillus conidia instilled into the lung revealed that MCP-1 and CCR2 play a role in anti-fungal responses; in contrast, we used a non-viable Aspergillus antigen preparation known to induce a robust eosinophilic inflammatory response. Results We found that wild-type C57BL/6 mice developed eosinophilic airway inflammation, goblet cell hyperplasia, airway hyperreactivity, elevations in serum IgE, and airway fibrosis in response to airway challenge with Aspergillus antigen. Surprisingly, mice deficient in either MCP-1 or CCR2 had responses to Aspergillus antigen similar to those seen in wild-type mice, including production of Th2 cytokines. Conclusion We conclude that robust Th2-mediated lung pathology can occur even in the complete absence of MCP-1 or CCR2.

  14. Effect of hsm mutations enhancing spontaneous mutability on induced mutagenesis and mitotic recombination in Saccharomyces cerevisiae yeast

    International Nuclear Information System (INIS)

    Fedorova, I.V.; Koval'tsova, S.V.; Ivanov, E.L.

    1993-01-01

    The authors have studied the effect of five nonallelic hms1-hms5 mutations on the incidence of direct mutations in loci ADE1 and ADE2, induced by UV-radiation, 6-hydroxyl-aminopurine, and nitrosomethylurea. All hms mutants were found to be insensitive to the lethal action of these mutagens. The frequency of UV-induced mutations to adenine dependence was increased in mutants hsm2-1, hsm3-1, hsm5-1, and particularly in hsm1-1, but remained unchanged in hsm4-1 compared to HSM. Mutagenesis induced by 6-hydroxylaminopurine was increased in all mutants studied, particularly in mutant hsm3-1. The authors did not detect any appreciable effect of hsm mutations on mutagenesis induced by nitrosomethylurea. The frequency of spontaneous mitotic conversion to prototrophy was studied in diploids heteroallelic to gene ADE2 and homo- and heterozygous for hsm mutations. Mutation hsm5-1 considerably increased the frequency of conversion for all heteroalleles studied, mutations hsm1-1 and hsm3-1 also considerably increased the conversion frequency, while mutations hsm1-1 and hsm4-1 had little effect on this process. The study of the properties of hsm mutations revealed joint genetic control of spontaneous and induced mutagenesis and recombination in yeast. The possibility that hsm mutations belong to the class of mutations impairing correction of unpaired DNA bases is discussed. 25 refs., 3 figs., 3 tabs

  15. Can resting B cells present antigen to T cells

    International Nuclear Information System (INIS)

    Ashwell, J.D.; DeFranco, A.L.; Paul, W.E.; Schwartz, R.H.

    1985-01-01

    Antigen stimulation of T lymphocytes can occur only in the presence of an antigen-presenting cell (APC). An ever-increasing number of cell types have been found to act as APCs; these include macrophages, splenic and lymph node dendritic cells, and Langerhans cells of the skin. Although activated B lymphocytes and B cell lymphomas are known to serve as APCs, it has been generally believed that resting B cells cannot perform this function. However, in recent studies the authors have found that resting B cells can indeed present soluble antigen to T cell clones as well as to antigen-primed T cells. The previous difficulty in demonstrating this activity can be explained by the finding that, in contrast to macrophages and dendritic cells, the antigen-presenting ability of resting B cells is very radiosensitive. Macrophages are usually irradiated with 2000-3300 rads to prevent them from incorporating [ 3 H]thymidine in the T cell proliferation assay. Resting B cells, however, begin to lose presenting function at 1500 rads and have completely lost this activity at 3300 rads. It was also possible to distinguish two distinct T cell clonal phenotypes when resting B cells were used as APCs on the basis of two different assays (T cell proliferation, and B cell proliferation resulting from T cell activation). The majority of T cell clones tested were capable of both proliferating themselves and inducing the proliferation of B cells. Some T cells clones, however, could not proliferate in the presence of antigen and B cell APCs, although they were very good at inducing the proliferation of B cells

  16. Naive T lymphocytes traffic to inflamed central nervous system, but require antigen recognition for activation

    DEFF Research Database (Denmark)

    Krakowski, M L; Owens, T

    2000-01-01

    Organ-specific autoimmune diseases may be induced by infiltration of the target tissue by CD4(+) T cells with specificity for self antigen(s). As disease progresses, T cells of other specificities appear in the tissue. Traffic of naive, antigen-inexperienced T cells to target tissues has not been...

  17. CD8+ T Cells Induce Fatal Brainstem Pathology during Cerebral Malaria via Luminal Antigen-Specific Engagement of Brain Vasculature.

    Directory of Open Access Journals (Sweden)

    Phillip A Swanson

    2016-12-01

    Full Text Available Cerebral malaria (CM is a severe complication of Plasmodium falciparum infection that results in thousands of deaths each year, mostly in African children. The in vivo mechanisms underlying this fatal condition are not entirely understood. Using the animal model of experimental cerebral malaria (ECM, we sought mechanistic insights into the pathogenesis of CM. Fatal disease was associated with alterations in tight junction proteins, vascular breakdown in the meninges / parenchyma, edema, and ultimately neuronal cell death in the brainstem, which is consistent with cerebral herniation as a cause of death. At the peak of ECM, we revealed using intravital two-photon microscopy that myelomonocytic cells and parasite-specific CD8+ T cells associated primarily with the luminal surface of CNS blood vessels. Myelomonocytic cells participated in the removal of parasitized red blood cells (pRBCs from cerebral blood vessels, but were not required for the disease. Interestingly, the majority of disease-inducing parasite-specific CD8+ T cells interacted with the lumen of brain vascular endothelial cells (ECs, where they were observed surveying, dividing, and arresting in a cognate peptide-MHC I dependent manner. These activities were critically dependent on IFN-γ, which was responsible for activating cerebrovascular ECs to upregulate adhesion and antigen-presenting molecules. Importantly, parasite-specific CD8+ T cell interactions with cerebral vessels were impaired in chimeric mice rendered unable to present EC antigens on MHC I, and these mice were in turn resistant to fatal brainstem pathology. Moreover, anti-adhesion molecule (LFA-1 / VLA-4 therapy prevented fatal disease by rapidly displacing luminal CD8+ T cells from cerebrovascular ECs without affecting extravascular T cells. These in vivo data demonstrate that parasite-specific CD8+ T cell-induced fatal vascular breakdown and subsequent neuronal death during ECM is associated with luminal, antigen

  18. Polymer nanoparticles for cross-presentation of exogenous antigens and enhanced cytotoxic T-lymphocyte immune response

    Directory of Open Access Journals (Sweden)

    Song C

    2016-08-01

    Full Text Available Chanyoung Song,* Young-Woock Noh,* Yong Taik Lim SKKU Advanced Institute of Nanotechnology (SAINT, School of Chemical Engineering, Sungkyunkwan University, Suwon, South Korea *These authors contributed equally to this work Abstract: Effective induction of an antigen-specific cytotoxic T lymphocyte (CTL immune response is one of the key goals of cancer immunotherapy. We report the design and fabrication of polyethylenimine (PEI-coated polymer nanoparticles (NPs as efficient antigen-delivery carriers that can induce antigen cross-presentation and a strong CTL response. After synthesis of poly(d,l-lactide-co-glycolide (PLGA NPs containing ovalbumin (OVA by the double-emulsion solvent-evaporation method, cationic-charged PLGA NPs were generated by coating them with PEI. In a methyl tetrazolium salt assay, no discernible cytotoxic effect of PEI-coated PLGA (OVA NPs was observed. The capacity and mechanism of PEI-coated PLGA (OVA NPs for antigen delivery and cross-presentation on dendritic cells (DCs were determined by fluorescence microscopy and flow cytometry. PEI-coated PLGA (OVA NPs were internalized efficiently via phagocytosis or macropinocytosis in DCs and induced efficient cross-presentation of the antigen on MHC class I molecules via both endosome escape and a lysosomal processing mechanism. The DCs treated with PEI-coated PLGA (OVA NPs induced a release of IL-2 cytokine from OVA-specific CD8-OVA1.3 T cells more efficiently than DCs treated with PLGA (OVA NPs. Therefore, the PEI-coated PLGA (OVA NPs can induce antigen cross-presentation and are expected to be used for induction of a strong CTL immune response and for efficient anticancer immunotherapy. Keywords: antigen delivery, dendritic cells, polymer NPs, vaccine, cross-presentation

  19. 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.

  20. 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.