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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/12499
Title: HUMAN IMMUNE RESPONSE TO ANTIGEN (S) OF Mycobacterium tuberculosis RELEVANT TO NON-REPLICATING PERSISTENT (LATENT) TUBERCULOSIS IN ETHIOPIA
???metadata.dc.contributor.*???: Dr. Girmai Gebru
Dr. Mekebe Afework
GEZAHEGNE, MAMO
Keywords: ex-vivo;NRP-TB
Issue Date: 13-Jul-2005
Abstract: One third of the world's population harbours Mycobacterium tuberculosis (Mtb) in Non-Replicating Persistent-NRP (latent) state having the potential to reactivate causing active clinical disease following any immune suppression. During NRP-TB, Mtb enters into stationary phase showing enhanced gene expression of alpha-crystallin (acr). This could be a possible target to study the immune response in NRP-TB. This study focuses on the understanding of the human immune responses to alpha crystallin antigen and other relevant antigens of Mtb in index patients, their healthy household contacts and community control groups in the endemic Addis Ababa population. One hundred forty peripheral blood samples were collected from three groups of study participants categorized based on their status of exposure to tuberculosis infection from a population of Addis Ababa during the period during December 2004 and April 2005, out of which 87 comprising of 39 index patients, 23 healthy household contacts and 25 community controls were analysed in detail for the results. An ex-vivo enzyme-linked immunospot (ELISPOT) assay for human interferon-γ was used to assess the T cell immune response to antigens of Mtb in study participants with particular emphasis on the alpha-crystallin antigen, which is relevant to NRP-TB. The result obtained demonstrated that there is a statistically significant difference in T cell response to alpha crystallin antigen of Mtb between community controls and index patients (p=0.011). The proportions of responders to alpha crystallin were 36% in index patients, 48% in health household contacts and 76% in community control group. Based on the assessment of the proportion of responders to specific Mtb complex antigen, ESAT-6, 60% of community controls, 61% of healthy household contacts and 54% of index patients showed antigen-specific T cell responses. We conclude that previous exposure to Mtb infection and NRP-TB could be assessed using alpha-crystallin as a marker of NRP-TB as we observed significant differences in T cell recognition among apparently healthy adult community controls as compared to the index patients using ex-vivo ELISPOT assay. NRP-TB is more dominant in the community control group than the healthy household contacts based on our results of alpha-crystallin specific T cell responses.
Description: A THESIS SUBMITTED TO THE POSTGRADUATE AND RESEARCH PROGRAM OF ADDIS ABABA UNIVERSITY IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN ANATOMY
URI: http://hdl.handle.net/123456789/12499
Appears in Collections:Thesis - Tropical Veternery Medicine

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