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Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools

Thesis (PhD)--University of Pretoria, 2012.

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Other Authors: Khati, Makobetsa
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Published: University of Pretoria 2013
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access_status_str Open Access
author2 Khati, Makobetsa
author_browse Khati, Makobetsa
author_facet Khati, Makobetsa
collection Thesis
dc_rights_str_mv © 2012 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Thesis (PhD)--University of Pretoria, 2012.
format Thesis
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institution University of Pretoria (South Africa)
last_indexed 2026-06-10T12:36:53.259Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2013
publishDateRange 2013
publishDateSort 2013
publisher University of Pretoria
publisherStr University of Pretoria
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source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/30803 Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools Khati, Makobetsa Theron, Jacques Khati, Makobetsa upetd@up.ac.za Theron, Jacques Rotherham, Lia S. UCTD Thesis (PhD)--University of Pretoria, 2012. Tuberculosis (TB) is one of the biggest killers among infectious diseases, despite the worldwide use of a live attenuated vaccine and several antibiotics. There are an estimated eight million new cases per year and two million deaths annually, which are compounded by the emergence of drug resistance TB and co-infections with HIV. As of 2004, it was estimated that more than 4% of the world’s infected people living with active TB are in South Africa. During this period, South Africa accounted for about 2% of the world’s new TB cases; and approximately 3% of the total deaths due to TB. Despite the enormous burden of TB, conventional approaches to diagnosis used today continue to rely on tests that have major drawbacks. Many of these tests are slow and lack both sensitivity and specificity or require expensive equipment and trained personnel. For example, sputum smear microscopy is insensitive; the culture method is technically complex and slow; chest radiography is non-specific; the tuberculin skin test is imprecise and the results are non-specific; nucleic acid amplification tests and phage display are rapid but specificity and sensitivity are low; and the GeneXpert™ addresses the problems of time and sensitivity but the machine required is extremely expensive. Clearly, TB diagnostics need to be improved and a more specific diagnostic assay should preferably be based on antigens that are present exclusively in Mycobacterium tuberculosis (Mtb) and not in Bacillus Calmette-Guérin (BCG). To help improve TB diagnostics, a systematic evolution of ligands by exponential enrichment (SELEX) process was used to select aptamers that can specifically bind to the CFP-10/ESAT-6 heterodimer, which is an early marker of TB. Anti-CFP-10/ESAT-6 aptamers were screened using an enzyme-linked oligonucleotide assay (ELONA) for binding affinity and specificity. A total of 24 aptamers had significant binding to the CFP-10/ESAT-6 heterodimer. One aptamer, named EA10, which bound to the heterodimer with a dissociation constant (KD) of 8 nM, as determined by surface plasmon resonance (SPR), was used for a proof-of-principle in a TB diagnostic test. Evaluation of 80 clinical sputum samples from TB patients revealed that aptamer EA10 has a specificity of 68% and a sensitivity of 80-100%. These data bode well for the development of the aptamer for accurate diagnosis of TB. Microbiology and Plant Pathology Unrestricted 2013-09-09T07:35:47Z 2013-05-20 2013-09-09T07:35:47Z 2013-04-12 2012 2013-05-05 Thesis Rotherham, LS 2013, Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools , PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/30803 > D13/4/490/ag http://hdl.handle.net/2263/30803 http://upetd.up.ac.za/thesis/available/etd-05052013-135019/ © 2012 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools
title Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools
title_full Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools
title_fullStr Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools
title_full_unstemmed Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools
title_short Isolation and characterization of novel aptamers against the CFP-10/ESAT-6 heterodimer for the development of TB diagnostic tools
title_sort isolation and characterization of novel aptamers against the cfp 10 esat 6 heterodimer for the development of tb diagnostic tools
topic UCTD
url http://hdl.handle.net/2263/30803
http://upetd.up.ac.za/thesis/available/etd-05052013-135019/