Project description:Tuberculosis kills nearly 2 million people through out the world, every year. The outcome of M. tuberculosis infection is determined by the host and bacterial factors. A strong host immune response controls the growth of the bacilli effectively. However, in a host with suboptimal immune response, the bacilli grows and mounts disease. Activation of immune response following M. tuberculosis infection affects the expression of many host genes that are involved in the production of immune system molecules such as cytokines, chemokines, surface receptors and transcriptional regulators that manifest in the change of subsequent cellular events, including chemotaxis and proliferation of effector cells. The infecting bacilli counteracts the bactericidal activities of the host immune cells, primarily by modifying their gene expression. However, the specific nature of the host-pathogen interactions and the outcome of Mtb infection are not fully understood. Tumor necrosis factor-alpha (TNF-a), produced by the immune cells, is an important cytokine in protecting the host against Mtb infection. However, excessive TNF-a production leads to severe inflammation and host cell destruction. In fact, pharmacologic inhibition of TNF-a production has been considered as a therapeutic modality in inflammatory diseases. Interestingly, inhibitors of host phosphodiesterase-4 (PDE4) have been shown to reduce TNF-a production and dampen inflammation without complete immune suppression of the host. In this study, we have explored the use of one of the PDE4 inhibitors, CC-3052, as an adjunct immune modulatory drug, in combination with isoniazid (INH) treatment in rabbit pulmonary tuberculosis. We hypothesize that reducing TNF-a levels during Mtb infection would reduce the environmental pressure on the bacteria, rendering them more amenable to killing by INH. Mtb infected rabbits were treated with CC-3052 or INH or both and the lung tissue were harvested after 4 and 8 weeks of treatment. Lung bacterial load, histologic changes and host and bacterial gene expression were determined for each timepoint and compared between various treatment groups. The results of our study provides data to support the idea that combining anti-TB drugs with an adjunctive immune modulator may enhance the efficacy of current TB therapy regimens and shorten the duration of treatment if applied appropriately to humans. The microarray experiments involves 2 comparison groups. 1) Changes in rabbit gene expression between Mtb infected and uninfected animals; 2). Changes in rabbit gene expression between CC-3052 treated and untreated animals during Mtb infection at 4,8 and 12 weeks post infection.

Project description:Tuberculosis kills nearly 2 million people through out the world, every year. The outcome of M. tuberculosis infection is determined by the host and bacterial factors. A strong host immune response controls the growth of the bacilli effectively. However, in a host with suboptimal immune response, the bacilli grows and mounts disease. Activation of immune response following M. tuberculosis infection affects the expression of many host genes that are involved in the production of immune system molecules such as cytokines, chemokines, surface receptors and transcriptional regulators that manifest in the change of subsequent cellular events, including chemotaxis and proliferation of effector cells. The infecting bacilli counteracts the bactericidal activities of the host immune cells, primarily by modifying their gene expression. However, the specific nature of the host-pathogen interactions and the outcome of Mtb infection are not fully understood. Tumor necrosis factor-alpha (TNF-a), produced by the immune cells, is an important cytokine in protecting the host against Mtb infection. However, excessive TNF-a production leads to severe inflammation and host cell destruction. In fact, pharmacologic inhibition of TNF-a production has been considered as a therapeutic modality in inflammatory diseases. Interestingly, inhibitors of host phosphodiesterase-4 (PDE4) have been shown to reduce TNF-a production and dampen inflammation without complete immune suppression of the host. In this study, we have explored the use of one of the PDE4 inhibitors, CC-3052, as an adjunct immune modulatory drug, in combination with isoniazid (INH) treatment in rabbit pulmonary tuberculosis. We hypothesize that reducing TNF-a levels during Mtb infection would reduce the environmental pressure on the bacteria, rendering them more amenable to killing by INH. Mtb infected rabbits were treated with CC-3052 or INH or both and the lung tissue were harvested after 4 and 8 weeks of treatment. Lung bacterial load, histologic changes and host and bacterial gene expression were determined for each timepoint and compared between various treatment groups. The results of our study provides data to support the idea that combining anti-TB drugs with an adjunctive immune modulator may enhance the efficacy of current TB therapy regimens and shorten the duration of treatment if applied appropriately to humans. The microarray experiments involves 2 comparison groups. 1) Changes in rabbit gene expression between Mtb infected and uninfected animals; 2). Changes in rabbit gene expression between CC-3052 treated and untreated animals during Mtb infection at 4,8 and 12 weeks post infection. New Zealand White rabbits were infected with Mtb HN878 at 3.2log10 (on day 0). At 4 weeks post infection, one group of infected rabbits were treated with a phosphodiesterase-4 (PDE4) inhibitor, CC-3052, and the treatment was continued up to 12 weeks post infection. The compound was used at 25mg/kg body weight, dissolved in distilled water and administered through gavage five days a weeks. Lung tissue from Uninfected, Mtb-infected and Untreated or CC-3052 treated rabbits were isolated at Day0, 4,8 and 12 weeks post infection and used for total RNA extraction. Only the 8 and 12 week timepoints correspond to the associated publication.

Project description:Background Identification of patients at risk of tuberculosis relapse following treatment would revolutionize clinical trials of new drugs and regimens and facilitate clinical management. The study aim was to determine whether tuberculosis patients who subsequently suffer relapse have different immune responses to mycobacteria in vitro compared to patients who remain cured for two years post-treatment. Methods First episode pulmonary tuberculosis patients were recruited into a surrogate marker study in Cape Town, South Africa. Peripheral blood samples were collected at diagnosis and after two and four weeks of tuberculosis treatment. Diluted blood was cultured with live Mycobacterium tuberculosis for six days and cellular RNA was frozen. Gene expression in samples from ten patients who subsequently relapsed, confirmed by stain genotyping, was compared to those who remained cured using Affymetrix microarrays. Results At diagnosis, the expression of 668 genes was significantly different in samples from patients who subsequently relapsed compared to successfully cured patients, and these differences persisted for at least four weeks. Gene Ontology and biological pathways analyses revealed the most significant difference was up-regulation of genes involved in cytotoxic cell-mediated killing, such as perforin, granulysin and fas ligand. Results were confirmed by qRT-PCR in a wider patient cohort. Conclusions These data show that patients who will subsequently relapse exhibit altered immune responses at diagnosis, including excessively robust cytolytic responses to M. tuberculosis in vitro, compared to patients who will achieve durable cure. Together with microbiological and clinical indices, these differences could be exploited for patient stratification in drugs trials, or for host-directed therapy development. Venous blood samples were diluted in culture medium and stimulated with live M. tuberculosis for 6 days. Samples from 10 TB patients who subsequently relapsed and 10 patients whore remained disease-free for 2 years. Samples collected at TB diagnosis and after 2 weeks or 4 weeks of treatment of first TB episode.

Project description:The aim of the project was to define transcriptional signatures in whole blood of TB patients (before drug treatment) and healthy controls to distinguish the signature of Latent and Active TB patients from each other and from healthy controls. This will help in diagnosis of active tuberculosis which normally relies on culture of the bacilli, which can take up to 6 wks, and sometimes the bacilli cannot be obtained from sputum thus requiring invasive techniques obtaining bronchoalveolar lavage (BAL). In some cases the bacill cannot be grown from sputum or BAL. Secondly the aim was to determine whether Latent patients have a homogeneous or heterogeneous signature, one may expect the latter since it is not possible to determine by the present tests (Tuberculin skin test - TST - or MTb antigen responsiveness of blood cells to produce IFN-gamma - IGRA assay) whether the mycobacteria has been cleared, is still present but is controlled, or if patients are recently infected or reactivated and will develop active TB. The latter situation may be determined if Latent patients have a blood transcriptional signature similar to that in Active patients. The transcriptional signature in Active TB patients may also provide information as to the factors leading to immunopathogenesis, thus possibly identifying therapeutic targets. The transcriptional profile in Latent TB may give information as to the protective factors controlling the infection, thus important for monitoring vaccine development. A further aim was to examine the transcriptional blood profile of active TB patients at the time of recruitment (before drug treatment) and then subsequently at specific time points after drug treatment to determine whether the signature is extingsuihed with treatment and when. London is a site of intermediate burden of TB - the study was initiated in London, across a broad range of ethnicities to obtain a robust signature that could be used in different developing countries where there is a high burden TB disease.

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Tuberculosis Patients Blood Gene Expression Through Treatment (cured and end-of-treatment patients)

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