Publications by authors named "Federico Carlos Blanco"

18 Publications

  • Page 1 of 1

Rv2577 of Is a Virulence Factor With Dual Phosphatase and Phosphodiesterase Functions.

Front Microbiol 2020 22;11:570794. Epub 2020 Oct 22.

Instituto de Agrobiotecnología y Biología Molecular (IABIMO), Instituto Nacional de Tecnología Agropecuaria-Consejo Nacional de Investigaciones Científicas y Técnicas (INTA-CONICET), INTA, Buenos Aires, Argentina.

Tuberculosis, a lung disease caused by , is one of the ten leading causes of death worldwide affecting mainly developing countries. can persist and survive inside infected cells through modulation of host antibacterial attack, i.e., by avoiding the maturation of phagosome containing mycobacteria to more acidic endosomal compartment. In addition, bacterial phosphatases play a central role in the interplay between host cells and . In this study, we characterized the Rv2577 of as a potential alkaline phosphatase/phosphodiesterase enzyme. By an kinetic assay, we demonstrated that purified Rv2577 expressed in displays both enzyme activities, as evidenced by using the artificial substrates NPP and bis-(NPP). In addition, a three-dimensional model of Rv2577 allowed us to define the catalytic amino acid residues of the active site, which were confirmed by site-directed mutagenesis and enzyme activity analysis, being characteristic of a member of the metallophosphatase superfamily. Finally, a mutation introduced in Rv2577 reduced the replication of in mouse organs and impaired the arrest of phagosomes containing mycobacteria in early endosomes; which indicates Rv2577 plays a role in virulence.
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http://dx.doi.org/10.3389/fmicb.2020.570794DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7642983PMC
October 2020

A Phenotypic Characterization of Two Isolates of a Multidrug-Resistant Outbreak Strain of with Opposite Epidemiological Fitness.

Biomed Res Int 2020 8;2020:4741237. Epub 2020 Apr 8.

Institute of Biotechnology, National Institute of Agricultural Technology (INTA)/IABIMO-CONICET (Instituto de Biotecnología, Instituto Nacional de Tecnología Agropecuaria), Argentina.

Tuberculosis (TB) is an infectious disease, caused by , primarily affecting the lungs. The strain of the Haarlem family named M was responsible for a large multidrug-resistant TB (MDR-TB) outbreak in Buenos Aires. This outbreak started in the early 1990s and in the mid 2000s still accounted for 29% of all MDR-TB cases in Argentina. By contrast, a clonal variant of strain M, named 410, has caused a single tuberculosis case since the onset of the outbreak. The molecular bases of the high epidemiological fitness of the M strain remain unclear. To assess its unique molecular properties, herein, we performed a comparative protein and lipid analysis of a representative clone of the M strain (Mp) and the nonprosperous M variant 410. We also evaluated their growth in low pH. The variant 410 had higher levels of latency proteins under standard conditions and delayed growth at low pH, suggesting that it is more sensitive to stress stimuli than Mp. Moreover, Mp showed higher levels of mycolic acids covalently attached to the cell wall and lower accumulation of free mycolic acids in the outer layer than the 410 strain. The low expression of latency proteins together with the reduced content of surface mycolic acids may facilitate Mp to evade the host immune responses.
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http://dx.doi.org/10.1155/2020/4741237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7168692PMC
January 2021

Bovine macrophages responses to the infection with virulent and attenuated Leptospira interrogans serovar Pomona.

Vet Microbiol 2019 Jun 2;233:124-132. Epub 2019 May 2.

Institute of Agrobiotechnology and Molecular Biology (IABIMO), INTA-CONICET Buenos Aires, Argentina. Electronic address:

Leptospirosis is a zoonosis, caused by pathogenic spirochetes of the genus Leptospira. Although cattle are usually the maintenance hosts of serovar Hardjo, Pomona is the most frequent serovar circulating in Argentina. The understanding of bovine innate immune response and the virulence of this serovar is important for future control measures. This work compares infection of bovine macrophages with the virulent L. interrogans sv Pomona strain AKRFB (P1) and its attenuated counterpart (P19). First, we confirmed attenuation in the hamster model. Mortality and lung hemorrhages occurred after P1 inoculation, while the survival rate was 100% in P19-infected animals. Cells infected with both strains showed statistically upregulated gene expression of pro-inflammatory cytokines, IL-1β, IL-6 and TNFα. The level of expression of anti-inflammatory cytokine IL-10 was statistically different between strains. Increased expression of IL-10 was observed only in P1-infected cells. For the first time, we describe macrophages extracellular traps induced by infection of bovine macrophages (bMETs) with both, the virulent and attenuated Leptospira interrogans Pomona strains. P1 was found higher internalized when the phagocytosis was inhibited, suggesting a cell entrance of this strain also by an independent-phagocytosis pathway. Furthermore, P1 was higher colocalized with acidic and late endosomal compartments compared with P19. This data emphasizes the importance to deepen in Leptospira bovine macrophages particular invasion mechanisms and, furthermore, underline the value of studying the main hosts.
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http://dx.doi.org/10.1016/j.vetmic.2019.04.033DOI Listing
June 2019

ERAP1 and PDE8A Are Downregulated in Cattle Protected against Bovine Tuberculosis.

J Mol Microbiol Biotechnol 2017 14;27(4):237-245. Epub 2017 Sep 14.

Instituto de Biotecnología, CICVyA-INTA, Buenos Aires, Argentina.

Bovine tuberculosis (bTB) is a zoonotic disease caused by Mycobacterium bovis that is responsible for significant economic losses worldwide. In spite of its relevance, the limited knowledge about the host immune responses that provide effective protection against the disease has long hampered the development of an effective vaccine. The identification of host proteins with an expression that correlates with protection against bTB would contribute to the understanding of the cattle defence mechanisms against M. bovis infection. In this study, we found that ERAP1 and PDE8A were downregulated in vaccinated cattle that were protected from experimental M. bovis challenge. Remarkably, both genes encode proteins that have been negatively associated with immune protection against bTB.
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http://dx.doi.org/10.1159/000479183DOI Listing
June 2018

Single nucleotide polymorphisms may explain the contrasting phenotypes of two variants of a multidrug-resistant Mycobacterium tuberculosis strain.

Tuberculosis (Edinb) 2017 03 4;103:28-36. Epub 2017 Jan 4.

Universidad de Buenos Aires, Facultad de Agronomía, Cátedra de Microbiología Agrícola.INBA-CONICET, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina. Electronic address:

Globally, about 4.5% of new tuberculosis (TB) cases are multi-drug-resistant (MDR), i.e. resistant to the two most powerful first-line anti-TB drugs. Indeed, 480,000 people developed MDR-TB in 2015 and 190,000 people died because of MDR-TB. The MDR Mycobacterium tuberculosis M family, which belongs to the Haarlem lineage, is highly prosperous in Argentina and capable of building up further drug resistance without impairing its ability to spread. In this study, we sequenced the whole genomes of a highly prosperous M-family strain (Mp) and its contemporary variant, strain 410, which produced only one recorded tuberculosis case in the last two decades. Previous reports have demonstrated that Mp induced dysfunctional CD8 cytotoxic T cell activity, suggesting that this strain has the ability to evade the immune response against M. tuberculosis. Comparative analysis of Mp and 410 genomes revealed non-synonymous polymorphisms in eleven genes and five intergenic regions with polymorphisms between both strains. Some of these genes and promoter regions are involved in the metabolism of cell wall components, others in drug resistance and a SNP in Rv1861, a gene encoding a putative transglycosylase that produces a truncated protein in Mp. The mutation in Rv3787c, a putative S-adenosyl-l-methionine-dependent methyltransferase, is conserved in all of the other prosperous M strains here analysed and absent in non-prosperous M strains. Remarkably, three polymorphic promoter regions displayed differential transcriptional activity between Mp and 410. We speculate that the observed mutations/polymorphisms are associated with the reported higher capacity of Mp for modulating the host's immune response.
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http://dx.doi.org/10.1016/j.tube.2016.12.007DOI Listing
March 2017

Mycobacterium bovis Requires P27 (LprG) To Arrest Phagosome Maturation and Replicate within Bovine Macrophages.

Infect Immun 2017 03 23;85(3). Epub 2017 Feb 23.

Instituto de Biotecnología, CICVyA-INTA, Nicolás Repetto y De Los Reseros, Buenos Aires, Argentina

causes tuberculosis in a wide variety of mammals, with strong tropism for cattle and eventually humans. P27, also called LprG, is among the proteins involved in the mechanisms of the virulence and persistence of and Here, we describe a novel function of P27 in the interaction of with its natural host cell, the bovine macrophage. We found that a deletion in the operon impairs the replication of in bovine macrophages. Importantly, we show for the first time that arrests phagosome maturation in a process that depends on P27. This effect is P27 specific since complementation with wild-type but not fully restored the wild-type phenotype of the mutant strain; this indicates that P55 plays no important role during the early events of infection. In addition, we also showed that the presence of P27 from decreases the association of LAMP-3 with bead phagosomes, indicating that P27 itself blocks phagosome-lysosome fusion by modulating the traffic machinery in the cell host.
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http://dx.doi.org/10.1128/IAI.00720-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5328499PMC
March 2017

Polymorphisms of 20 regulatory proteins between Mycobacterium tuberculosis and Mycobacterium bovis.

Microbiol Immunol 2016 Aug;60(8):552-60

Biotechnology Institute, National Institute of Agricultural Technology (INTA), Hurlingham 1686, Argentina.

Mycobacterium tuberculosis and Mycobacterium bovis are responsible for tuberculosis in humans and animals, respectively. Both species are closely related and belong to the Mycobacterium tuberculosis complex (MTC). M. tuberculosis is the most ancient species from which M. bovis and other members of the MTC evolved. The genome of M. bovis is over >99.95% identical to that of M. tuberculosis but with seven deletions ranging in size from 1 to 12.7 kb. In addition, 1200 single nucleotide mutations in coding regions distinguish M. bovis from M. tuberculosis. In the present study, we assessed 75 M. tuberculosis genomes and 23 M. bovis genomes to identify non-synonymous mutations in 202 coding sequences of regulatory genes between both species. We identified species-specific variants in 20 regulatory proteins and confirmed differential expression of hypoxia-related genes between M. bovis and M. tuberculosis.
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http://dx.doi.org/10.1111/1348-0421.12402DOI Listing
August 2016

Differential expression of immunogenic proteins on virulent Mycobacterium tuberculosis clinical isolates.

Biomed Res Int 2014 7;2014:741309. Epub 2014 Jul 7.

IMEX-CONICET, Academia Nacional de Medicina, Pacheco de Melo 3081, 1425 CABA, Argentina.

Molecular epidemiology has revealed that Mycobacterium tuberculosis (Mtb), formerly regarded as highly conserved species, displays a considerable degree of genetic variability that can influence the outcome of the disease as well as the innate and adaptive immune response. Recent studies have demonstrated that Mtb families found worldwide today differ in pathology, transmissibility, virulence, and development of immune response. By proteomic approaches seven proteins that were differentially expressed between a local clinical isolate from Latin-American-Mediterranean (LAM) and from Haarlem (H) lineages were identified. In order to analyze the immunogenic ability, recombinant Rv2241, Rv0009, Rv0407, and Rv2624c proteins were produced for testing specific antibody responses. We found that these proteins induced humoral immune responses in patients with drug-sensitive and drug-resistant tuberculosis with substantial cross-reactivity among the four proteins. Moreover, such reactivity was also correlated with anti-Mtb-cell surface IgM, but not with anti-ManLAM, anti-PPD, or anti-Mtb-surface IgG antibodies. Therefore, the present results describe new Mtb antigens with potential application as biomarkers of TB.
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http://dx.doi.org/10.1155/2014/741309DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4109345PMC
April 2015

Identification of potential biomarkers of disease progression in bovine tuberculosis.

Vet Immunol Immunopathol 2014 Aug 6;160(3-4):177-83. Epub 2014 May 6.

Microbiología Agrícola, Facultad de Agronomía, Universidad de Buenos Aires, INBA Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad de Buenos Aires, Argentina. Electronic address:

Bovine tuberculosis (bTB) remains an important animal and zoonotic disease in many countries. The diagnosis of bTB is based on tuberculin skin test and IFN-γ release assays (IGRA). Positive animals are separated from the herd and sacrificed. The cost of this procedure is difficult to afford for developing countries with high prevalence of bTB; therefore, the improvement of diagnostic methods and the identification of animals in different stages of the disease will be helpful to control the infection. To identify biomarkers that can discriminate between tuberculin positive cattle with and without tuberculosis lesions (ML+ and ML-, respectively), we assessed a group of immunological parameters with three different classification methods: lineal discriminant analysis (LDA), quadratic discriminant analysis (QDA) and K nearest neighbors (k-nn). For this purpose, we used data from 30 experimentally infected cattle. All the classifiers (LDA, QDA and k-nn) selected IL-2 and IL-17 as the most discriminatory variables. The best classification method was LDA using IL-17 and IL-2 as predictors. The addition of IL-10 to LDA improves the performance of the classifier to discriminate ML-individuals (93.3% vs. 86.7%). Thus, the expression of IL-17, IL-2 and, in some cases, IL-10 would serve as an additional tool to study disease progression in herds with a history of bTB.
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http://dx.doi.org/10.1016/j.vetimm.2014.04.008DOI Listing
August 2014

Role of the Mce1 transporter in the lipid homeostasis of Mycobacterium tuberculosis.

Tuberculosis (Edinb) 2014 Mar 2;94(2):170-7. Epub 2014 Jan 2.

Instituto de Biotecnología, CICVyA - INTA, N. Repetto and De los Reseros, Hurlingham 1686, Argentina. Electronic address:

Tuberculosis is one of the leading causes of mortality throughout the world. Mycobacterium tuberculosis, the causative agent of human tuberculosis, has developed several strategies involving proteins and other compounds known collectively as virulence factors to subvert human host defences and invade the human host. The Mce proteins are among these virulence-related proteins and are encoded by the mce1, mce2, mce3 and mce4 operons in the genome of M. tuberculosis. It has been proposed that these operons encode ABC-like lipid transporters; however, the nature of their substrates has only been revealed in the case of the Mce4 proteins. Here we found that the knockout of the mce1 operon alters the lipid profile of M. tuberculosis H37Rv and the uptake of palmitic acid. Thin layer chromatography and liquid chromatography-mass spectrometry analysis showed that the mce1 mutant accumulates more mycolic acids than the wild type and complemented strains. Interestingly, this accumulation of mycolic acid is exacerbated when bacteria are cultured in the presence of palmitic acid or arachidonic acid. These results suggest that the mce1 operon may serve as a mycolic acid re-importer.
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http://dx.doi.org/10.1016/j.tube.2013.12.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3951760PMC
March 2014

Draft Genome Sequence of Mycobacterium bovis 04-303, a Highly Virulent Strain from Argentina.

Genome Announc 2013 Nov 27;1(6). Epub 2013 Nov 27.

School of Computing, UFMS, Campo Grande, Mato Grosso do Sul, Brazil.

Mycobacterium bovis strain 04-303 was isolated from a wild boar living in a free-ranging field in Argentina. This work reports the draft genome sequence of this highly virulent strain and the genomic comparison of its major virulence-related genes with those of M. bovis strain AF2122/97 and Mycobacterium tuberculosis strain H37Rv.
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http://dx.doi.org/10.1128/genomeA.00931-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869323PMC
November 2013

Study of the in vivo role of Mce2R, the transcriptional regulator of mce2 operon in Mycobacterium tuberculosis.

BMC Microbiol 2013 Sep 5;13:200. Epub 2013 Sep 5.

Instituto de Biotecnología, CICVyA-INTA, N, Repetto and De los Reseros, Hurlingham 1686, Argentina.

Background: Tuberculosis is one of the leading causes of mortality throughout the world. Mycobacterium tuberculosis, the agent of human tuberculosis, has developed strategies involving proteins and other compounds called virulence factors to subvert human host defences and damage and invade the human host. Among these virulence-related proteins are the Mce proteins, which are encoded in the mce1, mce2, mce3 and mce4 operons of M. tuberculosis. The expression of the mce2 operon is negatively regulated by the Mce2R transcriptional repressor. Here we evaluated the role of Mce2R during the infection of M. tuberculosis in mice and macrophages and defined the genes whose expression is in vitro regulated by this transcriptional repressor.

Results: We used a specialized transduction method for generating a mce2R mutant of M. tuberculosis H37Rv. Although we found equivalent replication of the MtΔmce2R mutant and the wild type strains in mouse lungs, overexpression of Mce2R in the complemented strain (MtΔmce2RComp) significantly impaired its replication. During in vitro infection of macrophages, we observed a significantly increased association of the late endosomal marker LAMP-2 to MtΔmce2RComp-containing phagosomes as compared to MtΔmce2R and the wild type strains. Whole transcriptional analysis showed that Mce2R regulates mainly the expression of the mce2 operon, in the in vitro conditions studied.

Conclusions: The findings of the current study indicate that Mce2R weakly represses the in vivo expression of the mce2 operon in the studied conditions and argue for a role of the proteins encoded in Mce2R regulon in the arrest of phagosome maturation induced by M. tuberculosis.
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http://dx.doi.org/10.1186/1471-2180-13-200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3847441PMC
September 2013

Mycobacterium bovis Δmce2 double deletion mutant protects cattle against challenge with virulent M. bovis.

Tuberculosis (Edinb) 2013 May 19;93(3):363-72. Epub 2013 Mar 19.

Instituto de Biotecnología, INTA, N. Repetto y De los Reseros, 1686 Hurlingham, Buenos Aires, Argentina.

A Mycobacterium bovis strain deleted in mce2A and mce2B genes (M. bovis Δmce2) was tested as an experimental vaccine in cattle challenged with a virulent M. bovis strain. Three-and-a-half-month old calves (n = 5 to 6 per group) were vaccinated and challenged with a virulent strain of M. bovis by the intratracheal route 9 weeks after vaccination. A non-vaccinated group and a group vaccinated with BCG were included as controls. Blood samples were collected to measure IFN-γ by an interferon-gamma release assay (IGRA), cytometry and cytokine responses of bovine purified protein derivative (PPD) restimulated peripheral blood mononuclear cells (PBMCs). The IGRA test showed IFN-γ values similar to pre-vaccination except for the animals vaccinated with M. bovis Δmce2, where a significant increase was observed at 30 days post-vaccination. The expression of IL-2R on CD4(+) cells in response to PPD from the animals vaccinated with Δmce2 increased at 15 days post-vaccination compared to cells from non-vaccinated group. Vaccination of cattle with M. bovis Δmce2 induced the highest (P < 0.05) expression of IFN-γ and IL-17 mRNA upon PPD stimulation of PBMCs compared to vaccination with BCG or that for the non-vaccinated group. There was a weak positive correlation between the production of these proinflammatory cytokines post-vaccination and reduced pathology scores post-challenge. The animals were euthanized and necropsied 100 days after challenge. The group vaccinated with M. bovis Δmce2 displayed a significantly lower histopathological score for lesions in lungs and pulmonary lymph nodes than for the other groups (P < 0.05). A marked positive reaction to tuberculin intradermal test was observed post-vaccination in animals vaccinated with M. bovis Δmce2 compared to those vaccinated with BCG or the non-vaccinated group. In contrast, after challenge, non-vaccinated animals had greater skin test responses than the vaccinated animals. In summary, M. bovis Δmce2 is a promising vaccine candidate to control M. bovis pathogenesis in cattle.
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http://dx.doi.org/10.1016/j.tube.2013.02.004DOI Listing
May 2013

Vaccination with a BCG strain overexpressing Ag85B protects cattle against Mycobacterium bovis challenge.

PLoS One 2012 10;7(12):e51396. Epub 2012 Dec 10.

Núcleo de Biotecnologia, CDTec, Universidade Federal de Pelotas, Pelotas, Brazil.

Mycobacterium bovis is the causative agent of tuberculosis in cattle but also infects other animals, including humans. Previous studies in cattle have demonstrated that the protection induced by BCG is not complete. In order to improve the protection efficacy of BCG, in this study we overexpressed Ag85B in a BCG Pasteur strain, by using an expression system based on the use of an auxotrophic strain for the leucine amino acid, and complementation with leuD. We found that vaccination of cattle with BCG overexpressing Ag85B induced higher production of IL-17 and IL-4 mRNA upon purified protein derivative (PPDB) stimulation of peripheral blood mononuclear cells (PBMCs) than vaccination with BCG. Moreover, the IL-17 mRNA expression after vaccination negatively correlated with disease severity resulting from a subsequent challenge with M. bovis, suggesting that this cytokine is a potential biomarker of cattle protection against bovine tuberculosis. Importantly, vaccination with the recombinant BCG vaccine protected cattle better than the wild-type BCG Pasteur.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0051396PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3519572PMC
June 2013

Transcriptional response of peripheral blood mononuclear cells from cattle infected with Mycobacterium bovis.

PLoS One 2012 16;7(7):e41066. Epub 2012 Jul 16.

Instituto de Biotecnología-CICVyA, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires, Argentina.

Mycobacterium bovis is the causative agent of most cases of bovine tuberculosis. The identification of bTB biomarkers in specific stages of the disease will contribute to a better understanding of the immunopathology associated with tuberculosis and will enable their use in disease diagnosis and prognosis. The aim of this study was to evaluate the gene expression profile induced after specific stimulation of bovine peripheral blood mononuclear cells from cattle infected with M. bovis using the Affymetrix® GeneChip® Bovine Genome Array. A total of 172 genes showed differential expression profile that was statistically significant with log2-fold change >2.5 and <-2.5. Twenty-four out of these genes were upregulated and 148 were downregulated in bovine peripheral blood mononuclear cells of M. bovis-infected cattle. The highest differentially-expressed genes were related to immune and inflammatory responses, apoptosis, endocytosis, cellular trafficking and genes encoding proteins involved in cellular matrix degradation. Microarray results were confirmed in another group of infected cattle by RT-qPCR for the CD14, IL-1R, THBS1, MMP9 and FYVE genes. This study confirms previous findings that have shown that M. bovis infection in cattle results in the downregulation of immune response-related genes. Moreover, it validates the use of microarray platforms in combination with RT-qPCR to identify biomarkers of bovine tuberculosis. In addition, we propose CD14, IL-1R, THBS1, MMP9 and FYVE as potential biomarkers of bovine tuberculosis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0041066PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3397951PMC
January 2013

Assessment of the immune responses induced in cattle after inoculation of a Mycobacterium bovis strain deleted in two mce2 genes.

J Biomed Biotechnol 2012 5;2012:258353. Epub 2012 Jun 5.

Instituto de Biotecnología, CICVyA-INTA, N. Repetto y De los Reseros, 1686 Hurlingham, Argentina.

The generation of efficient candidate vaccines against bovine tuberculosis will contribute to the control of this zoonotic disease. Rationally attenuated Mycobacterium bovis strains generated by knockout of virulence genes are promising candidate vaccines. However, to be effective, these candidate vaccines should at least maintain the immunological properties of their virulent parental M. bovis strains. Therefore, the aim of this study was to obtain an M. bovis strain deleted in the mce2 genes and evaluate the effect of the mutation on the immunological profile elicited by the bacteria in cattle. We showed that the activation of CD4+ T cells in cattle inoculated with the mutant strain was equivalent to that in animals inoculated with the parental strain. Moreover, after in vitro stimulation, peripheral blood mononuclear cells from animals inoculated with the mutant produced higher levels of mRNA Th-1 cytokines than the parental strain. Therefore, these results indicate that the mce2 mutant is a promising candidate vaccine against bovine tuberculosis.
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http://dx.doi.org/10.1155/2012/258353DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374952PMC
January 2013

Knockout mutation of p27-p55 operon severely reduces replication of Mycobacterium bovis in a macrophagic cell line and survival in a mouse model of infection.

Virulence 2011 May-Jun;2(3):233-7. Epub 2011 May 1.

Instituto de Biotecnología, CICVyA-INTA, Buenos Aires, Argentina.

Integrity of p27-p55 operon has been demonstrated to be crucial for replication of Mycobacterium tuberculosis, the main agent of human tuberculosis, in the mouse model of infection. However, the individual contribution of each gene of the operon for the virulence of pathogenic Mycobacterium spp. still remains unclear. The operon is formed by two genes, p27 and p55. p27 gene encodes a lipoprotein that binds triacylated glycolipids and modulates the host immune responses by inhibiting the MHC-II Ag processing. Besides, p55 encodes an efflux pump that, together with P27, is involved in resistance to drugs. In this study, we evaluated the individual contribution of P27 and P55 to the virulence of Mycobacterium bovis, the etiological agent for bovine tuberculosis. Knockout mutation of p27-p55 operon in M. bovis severely decreased the virulence of the bacteria when assessed in a progressive model of pulmonary tuberculosis in Balb/c mice. In addition, the mutant strain showed poor replication in a murine macrophagic cell line. Virulence and intracellular replication were only restored when the mutant strain was complemented with a copy of the whole operon. The reintroduction of p55 into the mutant strain partially restored the virulence of the bacteria while no complementation was achieved with p27 individual gene. 
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http://dx.doi.org/10.4161/viru.2.3.15888DOI Listing
October 2011

Increased IL-17 expression is associated with pathology in a bovine model of tuberculosis.

Tuberculosis (Edinb) 2011 Jan 24;91(1):57-63. Epub 2010 Dec 24.

Instituto de Biotecnología, CICVyA-INTA, N. Repetto y De Reseros, 1686 Hurlingham, Buenos Aires, Argentina.

The identification of bovine tuberculosis (bTB) biomarkers in specific stages of the disease will contribute to a better understanding of the immunopathology associated with tuberculosis and to improve the disease diagnosis and prognosis. The aim of this study was to understand the changing profile of the immune responses during the course of infection and to identify biomarkers associated with pathology. Here we describe the immune response developed in experimentally infected cattle with field Mycobacterium bovis strains. Blood samples were taken from each animal at different time points after M. bovis intratracheal infection and lymphocyte subset activation and cytokine mRNA expression were determined from peripheral blood mononuclear cells in response to purified protein derivative (PPDB). We found that CD4 and CD8 activation during the early stages of infection, together with IL-17 gene expression, were positively associated with pathology. The results of this study provide evidences of the role of IL-17 in the immunopathology of tuberculosis and support the use of IL-17 as a potential biomarker with predictive value of prognosis in bTB.
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http://dx.doi.org/10.1016/j.tube.2010.11.007DOI Listing
January 2011
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