The role of cell type-specific tumour necrosis factor in protective immunity against neurotuberculosis

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dc.contributor.advisorJacobs, Muazzamen_ZA
dc.contributor.authorFrancisco, Ngiambudulu Mbanduen_ZA
dc.date.accessioned2014-10-21T13:47:44Z
dc.date.available2014-10-21T13:47:44Z
dc.date.issued2013en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractNeurotuberculosis is the most severe form of extra-pulmonary tuberculosis, characterised by the formation of rich foci a brain form of granulomas, and tuberculous meningitis. Granulomas contain mycobacteria by recruitment of immune cells that surround the bacteria. The cytokine tumour necrosis factor has been found to be involved in the recruitment of the immune cells and structure maintenance of granulomas. Tumour necrosis factor is a multifunctional proinflammatory cytokine which play a critical role in the initial and long-term host immune protection against Mycobacterium tuberculosis (M. tuberculosis) infection. This cytokine is synthesised by several cell types of hematopoetic origin, such as microglia/macrophages, neutrophils, dendritic cells and lymphocytes, and non-hematopoetic origin such as astrocytes and neurons. During neurotuberculosis, excess of tumour necrosis factor has been implicated in persisting hyperinflammation, however, deficiency of tumour necrosis factor lead to uncontrolled bacterial growth; both phenomena causing necrotic lysis. Thus, a need exists to investigate the contribution of tumour necrosis factor by specific cell types in the control of cerebral M. tuberculosis infection and its protective immune response. In this study, we investigated the role of tumour necrosis factor derived from neurons, microglia/macrophages, neutrophils, CD4+ and CD8+ T cells in host immunity against M. tuberculosis; using an experimental murine model with cell type-specific gene targeting. We found that mice deficient for tumour necrosis factor in neurons (NsTNF-/-), as well as from microglia/macrophages and neutrophils (M-TNF-/-) are not susceptible to M. tuberculosis infection with a phenotype similar to wild type mice. Interestingly, mice with ablation of tumour necrosis factor in myeloid (microglia/macrophages, neutrophils) and CD4+ and CD8+ T cells (MTTNF-/-) were highly susceptible to M. tuberculosis infection with a phenotype similar to that of complete deficient tumour necrosis factor (TNF-/-) mice, which succumbed by 21 days postinfection. Thus, it seems that the resistance observed in M-TNF-/- mice may be caused by the compensation of T cell-derived TNF whose function appeared as non-redundant. Impaired protective immunity observed in MT-TNF-/- and TNF-/- mice were related to alteration of cytokines and chemokines, and also to reduce antigen response and B cells IgM secretion. Our data suggest that neurons as well as microglia/macrophages and neutrophils derived tumor necrosis factor have a very limited role in protective cerebral immune responses. In MT-TNF-/- mice, TNF mediated protective immunity against cerebral M. tuberculosis infection requires primarily T cell-derived TNF as opposed to macrophage/neutrophil derived TNF. These findings may inform the development of immunomodulatory therapy strategies against neurotuberculosis.en_ZA
dc.identifier.apacitationFrancisco, N. M. (2013). <i>The role of cell type-specific tumour necrosis factor in protective immunity against neurotuberculosis</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Division of Immunology. Retrieved from http://hdl.handle.net/11427/8706en_ZA
dc.identifier.chicagocitationFrancisco, Ngiambudulu Mbandu. <i>"The role of cell type-specific tumour necrosis factor in protective immunity against neurotuberculosis."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Division of Immunology, 2013. http://hdl.handle.net/11427/8706en_ZA
dc.identifier.citationFrancisco, N. 2013. The role of cell type-specific tumour necrosis factor in protective immunity against neurotuberculosis. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Francisco, Ngiambudulu Mbandu AB - Neurotuberculosis is the most severe form of extra-pulmonary tuberculosis, characterised by the formation of rich foci a brain form of granulomas, and tuberculous meningitis. Granulomas contain mycobacteria by recruitment of immune cells that surround the bacteria. The cytokine tumour necrosis factor has been found to be involved in the recruitment of the immune cells and structure maintenance of granulomas. Tumour necrosis factor is a multifunctional proinflammatory cytokine which play a critical role in the initial and long-term host immune protection against Mycobacterium tuberculosis (M. tuberculosis) infection. This cytokine is synthesised by several cell types of hematopoetic origin, such as microglia/macrophages, neutrophils, dendritic cells and lymphocytes, and non-hematopoetic origin such as astrocytes and neurons. During neurotuberculosis, excess of tumour necrosis factor has been implicated in persisting hyperinflammation, however, deficiency of tumour necrosis factor lead to uncontrolled bacterial growth; both phenomena causing necrotic lysis. Thus, a need exists to investigate the contribution of tumour necrosis factor by specific cell types in the control of cerebral M. tuberculosis infection and its protective immune response. In this study, we investigated the role of tumour necrosis factor derived from neurons, microglia/macrophages, neutrophils, CD4+ and CD8+ T cells in host immunity against M. tuberculosis; using an experimental murine model with cell type-specific gene targeting. We found that mice deficient for tumour necrosis factor in neurons (NsTNF-/-), as well as from microglia/macrophages and neutrophils (M-TNF-/-) are not susceptible to M. tuberculosis infection with a phenotype similar to wild type mice. Interestingly, mice with ablation of tumour necrosis factor in myeloid (microglia/macrophages, neutrophils) and CD4+ and CD8+ T cells (MTTNF-/-) were highly susceptible to M. tuberculosis infection with a phenotype similar to that of complete deficient tumour necrosis factor (TNF-/-) mice, which succumbed by 21 days postinfection. Thus, it seems that the resistance observed in M-TNF-/- mice may be caused by the compensation of T cell-derived TNF whose function appeared as non-redundant. Impaired protective immunity observed in MT-TNF-/- and TNF-/- mice were related to alteration of cytokines and chemokines, and also to reduce antigen response and B cells IgM secretion. Our data suggest that neurons as well as microglia/macrophages and neutrophils derived tumor necrosis factor have a very limited role in protective cerebral immune responses. In MT-TNF-/- mice, TNF mediated protective immunity against cerebral M. tuberculosis infection requires primarily T cell-derived TNF as opposed to macrophage/neutrophil derived TNF. These findings may inform the development of immunomodulatory therapy strategies against neurotuberculosis. DA - 2013 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - The role of cell type-specific tumour necrosis factor in protective immunity against neurotuberculosis TI - The role of cell type-specific tumour necrosis factor in protective immunity against neurotuberculosis UR - http://hdl.handle.net/11427/8706 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/8706
dc.identifier.vancouvercitationFrancisco NM. The role of cell type-specific tumour necrosis factor in protective immunity against neurotuberculosis. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Division of Immunology, 2013 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/8706en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDivision of Immunologyen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.titleThe role of cell type-specific tumour necrosis factor in protective immunity against neurotuberculosisen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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