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  • 1
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    Online Resource
    Postgenomic Approach To Identify Novel Mycobacterium leprae Antigens with Potential To Improve Immunodiagnosis of Infection
    American Society for Microbiology ; 2005
    In:  Infection and Immunity Vol. 73, No. 9 ( 2005-09), p. 5636-5644
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 73, No. 9 ( 2005-09), p. 5636-5644
    Abstract: Early detection of Mycobacterium leprae infection is considered an important component of strategies aiming at reducing transmission of infection, but currently available diagnostic tools often lack sufficient sensitivity and specificity to reach this goal. Recent comparative genomics have revealed the presence of 165 M. leprae genes with no homologue in M. tuberculosis . We selected 17 of these genes for further study. All 17 genes were found to be expressed at the mRNA level in M. leprae from infected mice and from a multibacillary leprosy patient. Additional comparative genomic analyses of all currently available mycobacterial genome databases confirmed 12 candidate genes to be unique to M. leprae , whereas 5 genes had homologues in mycobacteria other than M. tuberculosis . Evaluation of the immunogenicity of all 17 recombinant proteins in PBMC from 127 Brazilians showed that five antigens (ML0576, ML1989, ML1990, ML2283, and ML2567) induced significant gamma interferon levels in paucibacillary leprosy patients, reactional leprosy patients, and exposed healthy controls but not in most multibacillary leprosy patients, tuberculosis patients, or endemic controls. Importantly, among exposed healthy controls 71% had no detectable immunoglobulin M antibodies to the M. leprae -specific PGL-I but responded to one or more M. leprae antigen(s). Collectively, the M. leprae proteins identified are expressed at the transcriptome level and can efficiently activate T cells of M. leprae -exposed individuals. These proteins may provide new tools to develop tests for specific diagnosis of M. leprae infection and may enhance our understanding of leprosy and its transmission.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.73.9.5636-5644.2005
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2005
    detail.hit.zdb_id: 1483247-1
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  • 2
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    T-Cell Recognition of the HspX Protein of Mycobacterium tuberculosis Correlates with Latent M. tuberculosis Infection but Not with M. bovis BCG Vaccination
    American Society for Microbiology ; 2007
    In:  Infection and Immunity Vol. 75, No. 6 ( 2007-06), p. 2914-2921
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 75, No. 6 ( 2007-06), p. 2914-2921
    Abstract: During stationary growth or in vitro conditions mimicking relevant aspects of latency, the HspX protein (Rv2031c) is specifically upregulated by Mycobacterium tuberculosis . In this study we compared T-cell responses against HspX and the secreted M. tuberculosis protein Ag85B (Rv1886c) in tuberculosis (TB) patients, tuberculin skin test-positive individuals, M. bovis BCG-vaccinated individuals, and healthy negative controls. Gamma interferon responses to HspX were significantly higher in M. tuberculosis -exposed individuals than in M. tuberculosis -unexposed BCG vaccinees. In contrast, no such differences were found with respect to T-cell responses against Ag85B. Therefore, BCG-based vaccines containing relevant fragments of HspX may induce improved responses against this TB latency antigen. To identify relevant major histocompatibility complex class I- and class II-restricted HspX-specific T-cell epitopes, we immunized HLA-A2/K b and HLA-DR3.Ab 0 transgenic (tg) mice with HspX. Two new T-cell epitopes were identified, p91-105 and p31-50, restricted via HLA-A*0201 and HLA-DRB1*0301, respectively. These epitopes were recognized by human T cells as well, underlining the relevance of HspX T-cell recognition both in vivo and in vitro. In line with the data in humans, BCG immunization of both tg strains did not lead to T-cell responses against HspX-derived epitopes, whereas nonlatency antigens were efficiently recognized. These data support the notion that BCG vaccination per se does not induce T-cell responses against the latency antigen, HspX. Thus, we suggest that subunit vaccines incorporating HspX and/or other latency antigens, as well as recombinant BCG strains expressing latency antigens need to be considered as new vaccines against TB.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.01990-06
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2007
    detail.hit.zdb_id: 1483247-1
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  • 3
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    Online Resource
    Cross-Reactive Immunity to Mycobacterium tuberculosis DosR Regulon-Encoded Antigens in Individuals Infected with Environmental, Nontuberculous Mycobacteria
    American Society for Microbiology ; 2009
    In:  Infection and Immunity Vol. 77, No. 11 ( 2009-11), p. 5071-5079
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 77, No. 11 ( 2009-11), p. 5071-5079
    Abstract: Mycobacterium tuberculosis DosR regulon-encoded antigens are highly immunogenic in M. tuberculosis -infected humans and are associated with latent tuberculosis infection. We have investigated the hypothesis that infection with or exposure to nontuberculous mycobacteria (NTM) can induce cross-reactive immunity to M. tuberculosis DosR regulon-encoded antigens since responsiveness has been observed in non- M. tuberculosis -exposed but purified protein derivative-responsive individuals. M. tuberculosis DosR regulon-encoded antigen-specific T-cell responses were studied in peripheral blood mononuclear cells (PBMCs) of NTM-infected/exposed individuals. BLASTP was used to determine the presence of M. tuberculosis DosR regulon-encoded protein orthologs among environmental mycobacteria and nonmycobacteria. Significant gamma interferon production was observed in PBMCs from NTM-infected/exposed individuals in response to M. tuberculosis DosR regulon-encoded antigens. DosR regulon-encoded protein orthologs were prominently present in tuberculous and environmental mycobacteria and surprisingly also in nonmycobacteria. The ubiquitous presence of the highly conserved DosR master regulator protein Rv3133c suggests that this is a general adaptive bacterial response regulator. We report a first series of M. tuberculosis antigens to which cross-reactive immunity is induced by NTM infection/exposure. The high conservation of M. tuberculosis DosR regulon-encoded antigens most likely enables them to induce cross-reactive T-cell responses.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.00457-09
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2009
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  • 4
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    Online Resource
    Longitudinal Phenotypic Analysis of Human Immunodeficiency Virus Type 1-Specific Cytotoxic T Lymphocytes: Correlation with Disease Progression
    American Society for Microbiology ; 1999
    In:  Journal of Virology Vol. 73, No. 11 ( 1999-11), p. 9153-9160
    Details
    In: Journal of Virology, American Society for Microbiology, Vol. 73, No. 11 ( 1999-11), p. 9153-9160
    Abstract: Few studies have examined longitudinal changes in human immunodeficiency virus type 1 (HIV)-specific cytotoxic T lymphocytes (CTL). To more closely define the natural history of HIV-specific CTL, we used HLA-peptide tetrameric complexes to study the longitudinal CD8 + T-cell response evolution in 16 A*0201-positive untreated individuals followed clinically for up to 14 years. As early as 1 to 2 years after seroconversion, we found a significant association between high frequencies of A*0201-restricted p17 Gag/Pol tetramer-binding cells and slower disease progression ( P 〈 0.01). We observed that responses could remain stable over many months, but any longitudinal changes that occurred were typically accompanied by reciprocal changes in RNA viral load. Phenotypic analysis with markers CD45RO, CD45RA, and CD27 identified distinct subsets of antigen-specific cells and the preferential loss of CD27 + CD45RO + cells during periods of rapid decline in the frequency of tetramer-binding cells. In addition we were unable to confirm previous studies showing a consistent selective loss of HIV-specific cells in the context of sustained Epstein-Barr virus-specific cell frequencies. Overall, these data support a role of HIV-specific CTL in the control of disease progression and suggest that the ultimate loss of such CTL may be preferentially from the CD27 + CD45RO + subset.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    URL: Article
    DOI: 10.1128/JVI.73.11.9153-9160.1999
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1999
    detail.hit.zdb_id: 1495529-5
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  • 5
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    Mycobacterium bovis BCG Vaccine Strains Lack narK2 and narX Induction and Exhibit Altered Phenotypes during Dormancy
    American Society for Microbiology ; 2008
    In:  Infection and Immunity Vol. 76, No. 6 ( 2008-06), p. 2587-2593
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 76, No. 6 ( 2008-06), p. 2587-2593
    Abstract: Mycobacterium tuberculosis is the causative agent of tuberculosis, a disease that affects one-third of the world's population. The sole extant vaccine for tuberculosis is the live attenuated Mycobacterium bovis bacillus Calmette-Guerin (BCG). We examined 13 representative BCG strains from around the world to ascertain their ability to express DosR-regulated dormancy antigens. These are known to be recognized by T cells of M. tuberculosis -infected individuals, especially those harboring latent infections. Differences in the expression of these antigens could be valuable for use as diagnostic markers to distinguish BCG vaccination from latent tuberculosis. We determined that all BCG strains were defective for the induction of two dormancy genes: narK2 (Rv1737c) and narX (Rv1736c). NarK2 is known to be necessary for nitrate respiration during anaerobic dormancy. Analysis of the narK2/X promoter region revealed a base substitution mutation in all tested BCG strains and M. bovis in comparison to the M. tuberculosis sequence. We also show that nitrate reduction by BCG strains during dormancy was greatly reduced compared to M. tuberculosis and varied between tested strains. Several dormancy regulon transcriptional differences were also identified among the strains, as well as variation in their growth and survival. These findings demonstrate defects in DosR regulon expression during dormancy and phenotypic variation between commonly used BCG vaccine strains.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.01235-07
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2008
    detail.hit.zdb_id: 1483247-1
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  • 6
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    HLA-B*35-Restricted CD8 + -T-Cell Epitope in Mycobacterium tuberculosis Rv2903c
    American Society for Microbiology ; 2002
    In:  Infection and Immunity Vol. 70, No. 2 ( 2002-02), p. 981-984
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 70, No. 2 ( 2002-02), p. 981-984
    Abstract: Few human CD8 + T-cell epitopes in mycobacterial antigens have been described to date. Here we have identified a novel HLA-B*35-restricted CD8 + T-cell epitope in Mycobacterium tuberculosis Rv2903c based on a reverse immunogenetics approach. Peptide-specific CD8 T cells were able to kill M. tuberculosis -infected macrophages and produce gamma interferon and tumor necrosis factor alpha.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.70.2.981-984.2002
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2002
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  • 7
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    Immunogenicity of Eight Dormancy Regulon-Encoded Proteins of Mycobacterium tuberculosis in DNA-Vaccinated and Tuberculosis-Infected Mice
    American Society for Microbiology ; 2007
    In:  Infection and Immunity Vol. 75, No. 2 ( 2007-02), p. 941-949
    Details
    In: Infection and Immunity, American Society for Microbiology, Vol. 75, No. 2 ( 2007-02), p. 941-949
    Abstract: Hypoxia and low concentrations of nitric oxide have been reported to upregulate in vitro gene expression of 48 proteins of the dormancy (DosR) regulon of Mycobacterium tuberculosis . These proteins are thought to be essential for the survival of bacteria during persistence in vivo and are targeted by the immune system during latent infection in humans. Here we have analyzed the immunogenicity of eight DosR regulon-encoded antigens by plasmid DNA vaccination of BALB/c and C57BL/6 mice, i.e., Rv1733c, Rv1738, Rv2029c ( pfkB ), Rv2031c/ hspX ( acr ), Rv2032 ( acg ), Rv2626c, Rv2627c, and Rv2628. Strong humoral and/or cellular Th1-type (interleukin-2 and gamma interferon) immune responses could be induced against all but one (Rv1738) of these antigens. The strongest Th1 responses were measured following vaccination with DNA encoding Rv2031c and Rv2626c. Using synthetic 20-mer overlapping peptides, 11 immunodominant, predicted major histocompatibility complex class II-restricted epitopes and one K d -restricted T-cell epitope could be identified. BALB/c and (B6D2)F 1 mice persistently infected with M. tuberculosis developed immune responses against Rv1733c, Rv2031c, and Rv2626c. These findings have implications for proof-of-concept studies in mice mimicking tuberculosis (TB) latency models and their extrapolation to humans for potential new vaccination strategies against TB.
    Type of Medium: Online Resource
    ISSN: 0019-9567 , 1098-5522
    URL: Article
    DOI: 10.1128/IAI.01137-06
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2007
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  • 8
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    Online Resource
    Evidence-Based Biosafety: a Review of the Principles and Effectiveness of Microbiological Containment Measures
    American Society for Microbiology ; 2008
    In:  Clinical Microbiology Reviews Vol. 21, No. 3 ( 2008-07), p. 403-425
    Details
    In: Clinical Microbiology Reviews, American Society for Microbiology, Vol. 21, No. 3 ( 2008-07), p. 403-425
    Abstract: We examined the available evidence on the effectiveness of measures aimed at protecting humans and the environment against the risks of working with genetically modified microorganisms (GMOs) and with non-GMO pathogenic microorganisms. A few principles and methods underlie the current biosafety practice: risk assessment, biological containment, concentration and enclosure, exposure minimization, physical containment, and hazard minimization. Many of the current practices are based on experience and expert judgment. The effectiveness of biosafety measures may be evaluated at the level of single containment equipment items and procedures, at the level of the laboratory as a whole, or at the clinical-epidemiological level. Data on the containment effectiveness of equipment and laboratories are scarce and fragmented. Laboratory-acquired infections (LAIs) are therefore important for evaluating the effectiveness of biosafety. For the majority of LAIs there appears to be no direct cause, suggesting that failures of biosafety were not noticed or that containment may have been insufficient. The number of reported laboratory accidents associated with GMOs is substantially lower than that of those associated with non-GMOs. It is unknown to what extent specific measures contribute to the overall level of biosafety. We therefore recommend that the evidence base of biosafety practice be strengthened.
    Type of Medium: Online Resource
    ISSN: 0893-8512 , 1098-6618
    URL: Article
    DOI: 10.1128/CMR.00014-08
    RVK:
    XA 36863
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2008
    detail.hit.zdb_id: 1497041-7
    SSG: 12
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  • 9
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    Online Resource
    Vigorous but Short-Term Gamma Interferon T-Cell Responses against a Dominant HLA-A*02-Restricted Measles Virus Epitope in Patients with Measles
    American Society for Microbiology ; 2003
    In:  Journal of Virology Vol. 77, No. 8 ( 2003-04-15), p. 5014-5016
    Details
    In: Journal of Virology, American Society for Microbiology, Vol. 77, No. 8 ( 2003-04-15), p. 5014-5016
    Abstract: The absolute and relative abundance of major histocompatibility complex class I-presented viral epitopes is important in the induction and maintenance of antiviral cytotoxic-T-lymphocyte (CTL) responses. We demonstrate that the supra-abundant HLA-A*0201-restricted peptide KLWESPQEI of the measles virus nonstructural C protein induces strong gamma interferon CD8 + -T-cell responses in children with acute measles. However, longitudinal analysis indicates that these responses are only short-lived. Thus, some viral epitopes that can be immunodominant during primary infection may fail to establish memory CTL responses.
    Type of Medium: Online Resource
    ISSN: 0022-538X , 1098-5514
    URL: Article
    DOI: 10.1128/JVI.77.8.5014-5016.2003
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2003
    detail.hit.zdb_id: 1495529-5
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  • 10
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    Online Resource
    ESAT-6/CFP-10 Fusion Protein and Peptides for Optimal Diagnosis of Mycobacterium tuberculosis Infection by Ex Vivo Enzyme-Linked Immunospot Assay in The Gambia
    American Society for Microbiology ; 2005
    In:  Journal of Clinical Microbiology Vol. 43, No. 5 ( 2005-05), p. 2070-2074
    Details
    In: Journal of Clinical Microbiology, American Society for Microbiology, Vol. 43, No. 5 ( 2005-05), p. 2070-2074
    Abstract: Overlapping peptides of Mycobacterium tuberculosis antigens ESAT-6 and CFP-10 offer increased specificity over the purified protein derivative skin test when they were used in an ex vivo enzyme-linked immunospot (ELISPOT) assay for gamma interferon detection for the diagnosis of M. tuberculosis infection from recent exposure. We assessed whether equivalent results could be obtained for a fusion protein of the two antigens and whether a combined readout would offer increased sensitivity in The Gambia. We studied the ELISPOT assay results for 488 household contacts of 88 sputum smear-positive tuberculosis (TB) cases. The proportions of subjects positive by each test and by the tests combined were assessed across an exposure gradient, defined according to sleeping proximity to a TB case. Eighty-eight (18%) subjects were positive for CFP-10 peptides, 148 (30%) were positive for ESAT-6 peptides, 161 (33%) were positive for both peptides, and 168 (34%) were positive for the fusion protein; 188 (39%) subjects had either a positive result for a peptide or a positive result for the fusion protein. There was reasonable agreement between the peptide and the protein results (kappa statistic = 0.78) and no significant discordance ( P = 0.38). There was a strong correlation between the fusion protein and combined peptide spot counts ( r = 0.9), and responses to the peptide and the proteins all increased significantly according to M. tuberculosis exposure. The proportion of subjects positive for either the pool of peptides or the fusion protein offered maximum sensitivity, being significantly higher than the proportion of subjects positive for ESAT-6 peptides alone ( P = 0.007). A fusion protein of ESAT-6 and CFP-10 is equivalent to overlapping peptides for the diagnosis of latent M. tuberculosis infection. Use of a combination of peptides and fusion protein offers improved sensitivity.
    Type of Medium: Online Resource
    ISSN: 0095-1137 , 1098-660X
    URL: Article
    DOI: 10.1128/JCM.43.5.2070-2074.2005
    RVK:
    XA 10000
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2005
    detail.hit.zdb_id: 1498353-9
    SSG: 12
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