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Peter Andersen - One of the best experts on this subject based on the ideXlab platform.
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esat 6 esxa and tb10 4 esxh based vaccines for pre and post exposure tuberculosis vaccination
PLOS ONE, 2013Co-Authors: Truc Thi Kim Thanh Hoang, Jes Dietrich, Claus Aagaard, Joseph P Cassidy, Gregory Dolganov, Gary K Schoolnik, Carina Vingsbo Lundberg, Else Marie Agger, Peter AndersenAbstract:The ESX systems from Mycobacterium tuberculosis are responsible for the secretion of highly immunogenic proteins of key importance for bacterial survival and growth. The two prototypic proteins, ESAT-6 (EsxA from ESX-1) and TB10.4 (EsxH from ESX-3) share a lot of characteristics regarding genome organization, size, antigenic properties, and vaccine potential but the two molecules clearly have very different roles in bacterial physiology. To further investigate the role of ESAT-6 and TB10.4 as preventive and post-exposure tuberculosis vaccines, we evaluated four different fusion-protein vaccines; H1, H4, H56 and H28, that differ only in these two components. We found that all of these vaccines give rise to protection in a conventional prophylactic vaccination model. In contrast, only the ESAT-6-containing vaccines resulted in significant protection against reactivation, when administered post-exposure. This difference in post-exposure activity did not correlate with a difference in gene expression during infection or a differential magnitude or quality of the vaccine-specific CD4 T cells induced by ESAT-6 versus TB10.4-containing vaccines. The post-exposure effect of the ESAT-6 based vaccines was found to be influenced by the infectious load at the time-point of vaccination and was abolished in chronically infected animals with high bacterial loads at the onset of vaccination. Our data demonstrate that there are specific requirements for the immune system to target an already established tuberculosis infection and that ESAT-6 has a unique potential in post-exposure vaccination strategies.
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exchanging esat6 with tb10 4 in an ag85b fusion molecule based tuberculosis subunit vaccine efficient protection and esat6 based sensitive monitoring of vaccine efficacy
Journal of Immunology, 2005Co-Authors: Jes Dietrich, Mark T Doherty, Claus Aagaard, Robert Leah, Anja Weinreich Olsen, Anette Stryhn, Peter AndersenAbstract:Previously we have shown that Ag85B-ESAT-6 is a highly efficient vaccine against tuberculosis. However, because the ESAT-6 Ag is also an extremely valuable diagnostic reagent, finding a vaccine as effective as Ag85B-ESAT-6 that does not contain ESAT-6 is a high priority. Recently, we identified a novel protein expressed by Mycobacterium tuberculosis designated TB10.4. In most infected humans, TB10.4 is strongly recognized, raising interest in TB10.4 as a potential vaccine candidate and substitute for ESAT-6. We have now examined the vaccine potential of this protein and found that vaccination with TB10.4 induced a significant protection against tuberculosis. Fusing Ag85B to TB10.4 produced an even more effective vaccine, which induced protection against tuberculosis comparable to bacillus Calmette-Guerin vaccination and superior to the individual Ag components. Thus, Ag85B-TB10 represents a new promising vaccine candidate against tuberculosis. Furthermore, having now exchanged ESAT-6 for TB10.4, we show that ESAT-6, apart from being an excellent diagnostic reagent, can also be used as a reagent for monitoring vaccine efficacy. This may open a new way for monitoring vaccine efficacy in clinical trials.
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esat 6 and cfp 10 in clinical versus environmental isolates of mycobacterium kansasii
The Journal of Infectious Diseases, 2005Co-Authors: Sandra M. Arend, Ida Rosenkrands, Peter Andersen, Jaap T Van Dissel, Petra E W De Haas, Eliane M S Leyten, Leen Rigouts, Wouter Mijs, Dick Van SoolingenAbstract:Mycobacterium kansasii consists of 5 genetically distinct groups, of which 2 are associated with human disease. Determinants of the differences in virulence are unknown. Potential genes of interest are ESAT-6 and cfp-10, which are associated with virulence of Mycobacterium tuberculosis and Mycobacterium bovis but are lacking in bacille Calmette-Guerin and in most environmental mycobacteria (M. kansasii is an exception). We investigated ESAT-6 and cfp-10 genes in 22 clinical and 14 environmental isolates of M. kansasii. Both were present in all isolates; each genetic group had its own characteristic Southern-blot pattern corresponding to a highly conserved fingerprint pattern. Nucleotide sequences of the genes differed 12.6% and 10.1%, respectively, from the M. tuberculosis homologues, but the deduced amino acid sequences were <5% different. In vitro, clinical and environmental genotypes of M. kansasii expressed CFP-10 and ESAT-6. Thus, virulence of M. kansasii is not directly related to ESAT-6 and cfp-10 genes or gene expression.
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use of esat 6 in the interferon γ test for diagnosis of bovine tuberculosis following skin testing
Veterinary Microbiology, 2001Co-Authors: Bryce M Buddle, Peter Andersen, J M Pollock, Terry J Ryan, Geoffrey W De LisleAbstract:Abstract The whole blood interferon-γ (IFN-γ) test has proven to be a practical ancillary test for re-testing cattle for bovine tuberculosis 8–28 days following tuberculin skin testing. An improvement in the specificity of the IFN-γ test could further reduce culling of false positive animals. The primary aim of this study was to evaluate a single mycobacterial antigen, ESAT-6 in the IFN-γ test for use in skin test-positive cattle. These skin test-positive cattle comprised 51 Mycobacterium bovis-infected animals from tuberculosis-infected herds and 85 non-infected animals from tuberculosis-free herds. The test based on ESAT-6 had a higher specificity than the test based on purified protein derivative (PPD) tuberculin, but this was offset by a small decrease in sensitivity. Use of a lower cut-off in the ESAT-6-based test improved the sensitivity, while still maintaining a very high specificity. A secondary aim in the study was to assess the ESAT-6 and PPD-based tests for detecting bovine tuberculosis in skin test-negative animals from a persistently infected herd. The PPD-based test detected the majority of the lesioned or M. bovis-culture positive animals, while the ESAT-6-based test detected a smaller proportion. The false negatives in the IFN-γ test from both the skin test-negative and positive groups were predominantly M. bovis-culture positive animals with no visible lesions. The current study has shown that a defined specific antigen such as ESAT-6 can markedly improve the specificity of the IFN-γ test for re-testing skin test-positive animals. An ESAT-6-based IFN-γ test could be particularly useful to reduce the false positive rate, yet still maintain an acceptable level of sensitivity.
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efficient protection against mycobacterium tuberculosis by vaccination with a single subdominant epitope from the esat 6 antigen
European Journal of Immunology, 2000Co-Authors: Anja Weinreich Olsen, Paul R Hansen, Arne Holm, Peter AndersenAbstract:We have investigated the vaccine potential of two peptides derived from the 6-kDa early secretory antigenic target (ESAT)-6 antigen in the mouse model of tuberculosis. The peptides were both strongly immunogenic in B6CBAF1 (H-2b,k) mice and primed recall responses of the same intensity after immunization. However, both tuberculosis infection and immunization with ESAT-6 resulted in responses focused towards ESAT-61-20. Multiple antigen peptide constructs as well as free peptides were emulsified with dimethyl dioctadecylammonium bromide/monophosphoryl lipid A/IL-2 and tested as experimental vaccines in an i.v. and aerosol model of tuberculosis in mice. The peptide were highly immunogenic and induced cellular responses of the same magnitude. However, only vaccines based on the subdominant ESAT-651-70 epitope promoted significant levels of protective immunity and the level of protection was equivalent to that achieved with ESAT-6 and BCG. These findings demonstrate the potential of peptide-based vaccines against tuberculosis and indicate that there is not direct correlation between the hierarchy of response to naturally processed peptides and their ability to induce protective immunity against Mycobacterium tuberculosis.
Robin M Warren - One of the best experts on this subject based on the ideXlab platform.
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evolution and expansion of the mycobacterium tuberculosis pe and ppe multigene families and their association with the duplication of the esat 6 esx gene cluster regions
BMC Evolutionary Biology, 2006Co-Authors: Nico Gey C Van Pittius, Samantha L Sampson, Hyeyoung Lee, Yeun Kim, Paul D Van Helden, Robin M WarrenAbstract:Background The PE and PPE multigene families of Mycobacterium tuberculosis comprise about 10% of the coding potential of the genome. The function of the proteins encoded by these large gene families remains unknown, although they have been proposed to be involved in antigenic variation and disease pathogenesis. Interestingly, some members of the PE and PPE families are associated with the ESAT-6 (esx) gene cluster regions, which are regions of immunopathogenic importance, and encode a system dedicated to the secretion of members of the potent T-cell antigen ESAT-6 family. This study investigates the duplication characteristics of the PE and PPE gene families and their association with the ESAT-6 gene clusters, using a combination of phylogenetic analyses, DNA hybridization, and comparative genomics, in order to gain insight into their evolutionary history and distribution in the genus Mycobacterium.
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evolution and expansion of the mycobacterium tuberculosis pe and ppe multigene families and their association with the duplication of the esat 6 esx gene cluster regions
BMC Evolutionary Biology, 2006Co-Authors: Nico Gey C Van Pittius, Samantha L Sampson, Hyeyoung Lee, Yeun Kim, Paul D Van Helden, Robin M WarrenAbstract:The PE and PPE multigene families of Mycobacterium tuberculosis comprise about 10% of the coding potential of the genome. The function of the proteins encoded by these large gene families remains unknown, although they have been proposed to be involved in antigenic variation and disease pathogenesis. Interestingly, some members of the PE and PPE families are associated with the ESAT-6 (esx) gene cluster regions, which are regions of immunopathogenic importance, and encode a system dedicated to the secretion of members of the potent T-cell antigen ESAT-6 family. This study investigates the duplication characteristics of the PE and PPE gene families and their association with the ESAT-6 gene clusters, using a combination of phylogenetic analyses, DNA hybridization, and comparative genomics, in order to gain insight into their evolutionary history and distribution in the genus Mycobacterium. The results showed that the expansion of the PE and PPE gene families is linked to the duplications of the ESAT-6 gene clusters, and that members situated in and associated with the clusters represent the most ancestral copies of the two gene families. Furthermore, the emergence of the repeat protein PGRS and MPTR subfamilies is a recent evolutionary event, occurring at defined branching points in the evolution of the genus Mycobacterium. These gene subfamilies are thus present in multiple copies only in the members of the M. tuberculosis complex and close relatives. The study provides a complete analysis of all the PE and PPE genes found in the sequenced genomes of members of the genus Mycobacterium such as M. smegmatis, M. avium paratuberculosis, M. leprae, M. ulcerans, and M. tuberculosis. This work provides insight into the evolutionary history for the PE and PPE gene families of the mycobacteria, linking the expansion of these families to the duplications of the ESAT-6 (esx) gene cluster regions, and showing that they are composed of subgroups with distinct evolutionary (and possibly functional) differences.
Nico Gey C Van Pittius - One of the best experts on this subject based on the ideXlab platform.
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evolution and expansion of the mycobacterium tuberculosis pe and ppe multigene families and their association with the duplication of the esat 6 esx gene cluster regions
BMC Evolutionary Biology, 2006Co-Authors: Nico Gey C Van Pittius, Samantha L Sampson, Hyeyoung Lee, Yeun Kim, Paul D Van Helden, Robin M WarrenAbstract:The PE and PPE multigene families of Mycobacterium tuberculosis comprise about 10% of the coding potential of the genome. The function of the proteins encoded by these large gene families remains unknown, although they have been proposed to be involved in antigenic variation and disease pathogenesis. Interestingly, some members of the PE and PPE families are associated with the ESAT-6 (esx) gene cluster regions, which are regions of immunopathogenic importance, and encode a system dedicated to the secretion of members of the potent T-cell antigen ESAT-6 family. This study investigates the duplication characteristics of the PE and PPE gene families and their association with the ESAT-6 gene clusters, using a combination of phylogenetic analyses, DNA hybridization, and comparative genomics, in order to gain insight into their evolutionary history and distribution in the genus Mycobacterium. The results showed that the expansion of the PE and PPE gene families is linked to the duplications of the ESAT-6 gene clusters, and that members situated in and associated with the clusters represent the most ancestral copies of the two gene families. Furthermore, the emergence of the repeat protein PGRS and MPTR subfamilies is a recent evolutionary event, occurring at defined branching points in the evolution of the genus Mycobacterium. These gene subfamilies are thus present in multiple copies only in the members of the M. tuberculosis complex and close relatives. The study provides a complete analysis of all the PE and PPE genes found in the sequenced genomes of members of the genus Mycobacterium such as M. smegmatis, M. avium paratuberculosis, M. leprae, M. ulcerans, and M. tuberculosis. This work provides insight into the evolutionary history for the PE and PPE gene families of the mycobacteria, linking the expansion of these families to the duplications of the ESAT-6 (esx) gene cluster regions, and showing that they are composed of subgroups with distinct evolutionary (and possibly functional) differences.
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evolution and expansion of the mycobacterium tuberculosis pe and ppe multigene families and their association with the duplication of the esat 6 esx gene cluster regions
BMC Evolutionary Biology, 2006Co-Authors: Nico Gey C Van Pittius, Samantha L Sampson, Hyeyoung Lee, Yeun Kim, Paul D Van Helden, Robin M WarrenAbstract:Background The PE and PPE multigene families of Mycobacterium tuberculosis comprise about 10% of the coding potential of the genome. The function of the proteins encoded by these large gene families remains unknown, although they have been proposed to be involved in antigenic variation and disease pathogenesis. Interestingly, some members of the PE and PPE families are associated with the ESAT-6 (esx) gene cluster regions, which are regions of immunopathogenic importance, and encode a system dedicated to the secretion of members of the potent T-cell antigen ESAT-6 family. This study investigates the duplication characteristics of the PE and PPE gene families and their association with the ESAT-6 gene clusters, using a combination of phylogenetic analyses, DNA hybridization, and comparative genomics, in order to gain insight into their evolutionary history and distribution in the genus Mycobacterium.
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the esat 6 gene cluster of mycobacterium tuberculosis and other high g c gram positive bacteria
Genome Biology, 2001Co-Authors: Nico Gey C Van Pittius, Junaid Gamieldien, Winston Hide, Gordon D Brown, Roland J Siezen, Albert D BeyersAbstract:Background The genome of Mycobacterium tuberculosis H37Rv has five copies of a cluster of genes known as the ESAT-6 loci. These clusters contain members of the CFP-10 (lhp) and ESAT-6 (ESAT-6) gene families (encoding secreted T-cell antigens that lack detectable secretion signals) as well as genes encoding secreted, cell-wall-associated subtilisin-like serine proteases, putative ABC transporters, ATP-binding proteins and other membrane-associated proteins. These membrane-associated and energy-providing proteins may function to secrete members of the ESAT-6 and CFP-10 protein families, and the proteases may be involved in processing the secreted peptide.
Peter Henrik Andersen - One of the best experts on this subject based on the ideXlab platform.
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esat 6 proteins protective antigens and virulence factors
Trends in Microbiology, 2004Co-Authors: Priscille Brodin, Ida Rosenkrands, Stewart T Cole, Peter Henrik Andersen, Roland BroschAbstract:The 6kDa early secreted antigenic target from Mycobacterium tuberculosis, ESAT-6, is the prototype of a novel family of small proteins of unknown function produced by Actinobacteria. Export of ESAT-6, a potent T-cell antigen, and related proteins requires a dedicated secretory apparatus that is encoded by a cluster of genes, several of which also code for proteins that are recognized strongly by T cells. ESAT-6 systems can thus be considered as immunogenicity islands and there is growing evidence that the corresponding genes are subject to selective pressure imposed by the immune system of the host. Recently, there has been major progress in understanding the biogenesis, secretion and antigenicity of ESAT-6 proteins and, at least in the case of ESAT-6 system 1, in unravelling their role in pathogenicity. Here, we discuss these findings and their implications for the development of new therapeutic and prophylactic interventions against tuberculosis.
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antigenic equivalence of human t cell responses to mycobacterium tuberculosis specific rd1 encoded protein antigens esat 6 and culture filtrate protein 10 and to mixtures of synthetic peptides
Infection and Immunity, 2000Co-Authors: Sandra M. Arend, Peter Henrik Andersen, Krista E Van Meijgaarden, Jaap T Van Dissel, Annemieke Geluk, Michael Theisen, Tom H M OttenhoffAbstract:The early secreted antigenic target 6-kDa protein (ESAT-6) and culture filtrate protein 10 (CFP-10) are promising antigens for reliable immunodiagnosis of tuberculosis. Both antigens are encoded by RD1, a genomic region present in all strains of Mycobacterium tuberculosis and M. bovis but lacking in all M. bovis bacillus Calmette-Guerin vaccine strains. Production and purification of recombinant antigens are laborious and costly, precluding rapid and large-scale testing. Aiming to develop alternative diagnostic reagents, we have investigated whether recombinant ESAT-6 (rESAT-6) and recombinant CFP-10 (rCFP-10) can be replaced with corresponding mixtures of overlapping peptides spanning the complete amino acid sequence of each antigen. Proliferation of M. tuberculosis-specific human T-cell lines in response to rESAT-6 and rCFP-10 and that in response to the corresponding peptide mixtures were almost completely correlated (r = 0.96, P < 0.0001 for ESAT-6; r = 0.98, P < 0.0001 for CFP-10). More importantly, the same was found when gamma interferon production by peripheral blood mononuclear cells in response to these stimuli was analyzed (r = 0.89, P < 0.0001 for ESAT-6; r = 0.89, P < 0.0001 for CFP-10). Whole protein antigens and the peptide mixtures resulted in identical sensitivity and specificity for detection of infection with M. tuberculosis. The peptides in each mixture contributing to the overall response varied between individuals with different HLA-DR types. Interestingly, responses to CFP-10 were significantly higher in the presence of HLA-DR15, which is the major subtype of DR2. These results show that mixtures of synthetic overlapping peptides have potency equivalent to that of whole ESAT-6 and CFP-10 for sensitive and specific detection of infection with M. tuberculosis, and peptides have the advantage of faster production at lower cost.
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detection of active tuberculosis infection by t cell responses to early secreted antigenic target 6 kda protein and culture filtrate protein 10
The Journal of Infectious Diseases, 2000Co-Authors: Sandra M. Arend, Peter Henrik Andersen, Krista E Van Meijgaarden, Jaap T Van Dissel, Rikke Louise Vinther Skjot, Yanri W Subronto, Tom H M OttenhoffAbstract:The purified protein derivative (PPD) skin test has no predictive value for tuberculosis (TB) in Mycobacterium bovis bacillus Calmette-Guerin (BCG)-vaccinated individuals because of cross-reactive responses to nonspecific constituents of PPD. T cell responses to early-secreted antigenic target 6-kDa protein (ESAT-6) and the newly identified culture filtrate protein 10 (CFP-10), 2 proteins specifically expressed by M. tuberculosis (MTB) but not by BCG strains, were evaluated. Most TB patients responded to ESAT-6 (92%) or CFP-10 (89%). A minority of BCG-vaccinated individuals responded to both ESAT-6 and CFP-10, their history being consistent with latent infection with MTB in the presence of protective immunity. No responses were found in PPD-negative controls. The sensitivity and specificity of the assay were 84% and 100%, respectively, at a cutoff of 300 pg of interferon-gamma/mL. These data indicate that ESAT-6 and CFP-10 are promising antigens for highly specific immunodiagnosis of TB, even in BCG-vaccinated individuals.
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comparative evaluation of low molecular mass proteins from mycobacterium tuberculosis identifies members of the esat 6 family as immunodominant t cell antigens
Infection and Immunity, 2000Co-Authors: Rikke Louise Vinther Skjot, Thomas Oettinger, Ida Rosenkrands, Pernille Ravn, Inger Brock, Susanne Jacobsen, Peter Henrik AndersenAbstract:Culture filtrate from Mycobacterium tuberculosis contains protective antigens of relevance for the generation of a new antituberculosis vaccine. We have identified two previously uncharacterized M. tuberculosis proteins (TB7.3 and TB10.4) from the highly active low-mass fraction of culture filtrate. The molecules were characterized, mapped in a two-dimensional electrophoresis reference map of short-term culture filtrate, and compared with another recently identified low-mass protein, CFP10 (F. X. Berthet, P. B. Rasmussen, I. Rosenkrands, P. Andersen, and B. Gicquel. Microbiology 144:3195-3203, 1998), and the well-described ESAT-6 antigen. Genetic analyses demonstrated that TB10.4 as well as CFP10 belongs to the ESAT-6 family of low-mass proteins, whereas TB7.3 is a low-molecular-mass protein outside this family. The proteins were expressed in Escherichia coli, and their immunogenicity was tested in cultures of peripheral blood mononuclear cells from human tuberculosis (TB) patients, Mycobacterium bovis BCG-vaccinated donors, and nonvaccinated donors. The two ESAT-6 family members, TB10.4 and CFP10, were very strongly recognized and induced gamma interferon release at the same level (CFP10) as or at an even higher level (TB10.4) than ESAT-6. The non-ESAT-6 family member, TB7.3, for comparison, was recognized at a much lower level. CFP10 was found to distinguish TB patients from BCG-vaccinated donors and is, together with ESAT-6, an interesting candidate for the diagnosis of TB. The striking immunodominance of antigens within the ESAT-6 family is discussed, and hypotheses are presented to explain this targeting of the immune response during TB infection.
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cellular immune responses to esat 6 discriminate between patients with pulmonary disease due to mycobacterium avium complex and those with pulmonary disease due to mycobacterium tuberculosis
Clinical and Vaccine Immunology, 1999Co-Authors: David A Lein, Pernille Ravn, Fordham C Von Reyn, Robert C Horsburgh, Lorraine N Alexander, Peter Henrik AndersenAbstract:ESAT-6 (for 6-kDa early secreted antigenic target) is a secreted antigen found almost exclusively in organisms of the Mycobacterium tuberculosis complex. We compared in vitro gamma interferon (IFN-γ) responses by peripheral blood mononuclear cells to this antigen in patients with pulmonary disease due to either Mycobacterium avium complex (MAC) or Mycobacterium tuberculosis with those in healthy, skin test-negative, control subjects. Significant IFN-γ responses to ESAT-6 were detected in 16 (59%) of 27 M. tuberculosis pulmonary disease patients, 0 (0%) of 8 MAC disease patients, and 0 (0%) of 8 controls. Significant IFN-γ responses to M. tuberculosis purified protein derivative were detected in 23 (85%) of 27 M. tuberculosis disease patients, 2 (25%) of 8 MAC disease patients, and 5 (63%) of 8 healthy controls. M. avium sensitin was recognized in 24 (89%) of 27 M. tuberculosis disease patients, 4 (50%) of 8 MAC disease patients, and 1 (13%) of 8 controls. IFN-γ responses to ESAT-6 are specific for disease due to M. tuberculosis and are not observed in patients with MAC disease or in healthy controls.
Ida Rosenkrands - One of the best experts on this subject based on the ideXlab platform.
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protective immunity to tuberculosis with ag85b esat 6 in a synthetic cationic adjuvant system ic31
Vaccine, 2006Co-Authors: Else Marie Agger, Ida Rosenkrands, Ann Williams, Claire Swetman Andersen, Anja Weinreich Olsen, Graham J Hatch, Constantia Kritsch, Karen Lingnau, Alexander Von Gabain, Karen Smith KorsholmAbstract:In this study, we evaluated the potential of a novel synthetic adjuvant designated IC31 for the ability to augment the immune response and protective efficacy of the well-known mycobacterial vaccine antigen, Ag85B-ESAT-6. The IC31 adjuvant, consisting of a vehicle based on the cationic peptide KLKL5KLK and the immunostimulatory oligodeoxynucleotide ODN1a signalling through the TLR9 receptor, was found to promote highly efficient Th1 responses. The combination of Ag85B-ESAT-6 and IC31 exhibited significant levels of protection in the mouse aerosol challenge model of tuberculosis and a detailed analysis of the immune response generated revealed the induction of CD4 T cells giving rise to high levels of IFN-γ secretion. Furthermore, the combination of Ag85B-ESAT-6/IC31 was found to confer efficient protection in the guinea pig aerosol model of tuberculosis infection and is at present moving towards clinical testing.
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Mycobacterium tuberculosis secreted protein ESAT-6 interacts with the human protein syntenin-1
Central European Journal of Biology, 2006Co-Authors: Gisbert Schumann, Ida Rosenkrands, Stewart T Cole, Marien I De Jonge, Susanne Schleier, Nina Nehmann, Steffi Hälbich, Peter F. Zipfel, Thomas Munder, Ute MöllmannAbstract:In order to study the function of the Mycobacterium tuberculosis protein ESAT-6 in the infection process, we searched for host proteins that interact with this secreted mycobacterial protein. Using a yeast two-hybrid system we identified the rat syntenin-1 protein as a candidate to interact with ESAT-6. This interaction was confirmed in vitro by protein overlay and by surface plasmon resonance using recombinant ESAT-6 and human syntenin-1, and by co-purification analysis of the mycobacterial expressed ESAT-6 and macrophage derived syntenin-1. The interaction domains were localized by two-hybrid studies using truncated derivatives of both proteins and by peptide spot analysis. Two domains of each protein mediate the ESAT-6/syntenin-1 interaction. The C-terminus of ESAT-6 binds to the PDZ-domains of syntenin-1 and the N-terminus of ESAT-6 binds to the N-terminus of syntenin-1. Thus, the host protein syntenin-1 represents a possible cellular receptor for the mycobacterial protein ESAT-6.
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esat 6 and cfp 10 in clinical versus environmental isolates of mycobacterium kansasii
The Journal of Infectious Diseases, 2005Co-Authors: Sandra M. Arend, Ida Rosenkrands, Peter Andersen, Jaap T Van Dissel, Petra E W De Haas, Eliane M S Leyten, Leen Rigouts, Wouter Mijs, Dick Van SoolingenAbstract:Mycobacterium kansasii consists of 5 genetically distinct groups, of which 2 are associated with human disease. Determinants of the differences in virulence are unknown. Potential genes of interest are ESAT-6 and cfp-10, which are associated with virulence of Mycobacterium tuberculosis and Mycobacterium bovis but are lacking in bacille Calmette-Guerin and in most environmental mycobacteria (M. kansasii is an exception). We investigated ESAT-6 and cfp-10 genes in 22 clinical and 14 environmental isolates of M. kansasii. Both were present in all isolates; each genetic group had its own characteristic Southern-blot pattern corresponding to a highly conserved fingerprint pattern. Nucleotide sequences of the genes differed 12.6% and 10.1%, respectively, from the M. tuberculosis homologues, but the deduced amino acid sequences were <5% different. In vitro, clinical and environmental genotypes of M. kansasii expressed CFP-10 and ESAT-6. Thus, virulence of M. kansasii is not directly related to ESAT-6 and cfp-10 genes or gene expression.
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esat 6 proteins protective antigens and virulence factors
Trends in Microbiology, 2004Co-Authors: Priscille Brodin, Ida Rosenkrands, Stewart T Cole, Peter Henrik Andersen, Roland BroschAbstract:The 6kDa early secreted antigenic target from Mycobacterium tuberculosis, ESAT-6, is the prototype of a novel family of small proteins of unknown function produced by Actinobacteria. Export of ESAT-6, a potent T-cell antigen, and related proteins requires a dedicated secretory apparatus that is encoded by a cluster of genes, several of which also code for proteins that are recognized strongly by T cells. ESAT-6 systems can thus be considered as immunogenicity islands and there is growing evidence that the corresponding genes are subject to selective pressure imposed by the immune system of the host. Recently, there has been major progress in understanding the biogenesis, secretion and antigenicity of ESAT-6 proteins and, at least in the case of ESAT-6 system 1, in unravelling their role in pathogenicity. Here, we discuss these findings and their implications for the development of new therapeutic and prophylactic interventions against tuberculosis.
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specific delayed type hypersensitivity responses to esat 6 identify tuberculosis infected cattle
Journal of Clinical Microbiology, 2003Co-Authors: J M Pollock, Ida Rosenkrands, Jim Mcnair, H Bassett, Joseph P Cassidy, E Costello, H Aggerbeck, Paal Skytt AndersenAbstract:Human and bovine tuberculosis have long been detected by skin testing with purified protein derivative (PPD), a complex mix of partly denatured mycobacterial antigens with suboptimal specificity. In the present study, skin tests based on ESAT-6, a recombinantly produced antigen highly specific for tuberculosis infection, were investigated. Although ESAT-6 was strongly recognized in vitro and induced high levels of gamma interferon, initial investigations demonstrated that higher doses of ESAT-6 than of PPD were needed to induce substantial delayed-type hypersensitivity reactions. Also, the kinetics of the skin test response differed for the two reagents; PPD showed maximal response at 72 h, but the response to ESAT-6 often peaked later at 96 h. Tests based on an optimized strategy (400 μg of ESAT-6 measured between 72 and 96 h), in cattle infected with Mycobacterium bovis (n = 22) and animals sensitized by exposure to environmental mycobacteria showed ESAT-6 to have a promising diagnostic potential (sensitivity, 82%; specificity, 100%; optimal cutoff, 3 mm), compared with PPD (sensitivity, 86%; specificity, 90%; optimal cutoff, 4 mm). Larger investigations are required to refine cutoff points for any new diagnostic test, but the present results indicate great potential for skin tests based on specific antigens for accurate in vivo diagnosis of tuberculosis.