Browsing by Author "Boom, W. Henry"

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    Analysis of host responses to secreted, latent and reactivation Mycobacterium tuberculosis antigens in a multi-site study of subjects with different TB and HIV infection states in sub-Saharan Africa
    (Public Library of Science, 2013-09-10) Sutherland, Jayne S.; Lalor, Maeve K.; Black, Gillian F.; Ambrose, Lyn R.; Loxton, Andre G.; Chegou, Novel N.; Kassa, Desta; Mihret, Adane; Howe, Rawleigh; Mayanja-Kizza, Harriet; Gomez, Marie P.; Donkor, Simon; Franken, Kees; Boom, W. Henry; Thiel, Bonnie A.; Crampin, Amelia C.; Hanekom, Willem; Klein, Michel R.; Parida, Shreemanta K.; Ota, Martin; Walzl, Gerhard; Ottenhoff, Tom H. M.; Dockrell, Hazel M.; Kaufmann, Stefan H. E.
    Background: Tuberculosis (TB) remains a global health threat with 9 million new cases and 1.4 million deaths per year. In order to develop a protective vaccine, we need to define the antigens expressed by Mycobacterium tuberculosis (Mtb), which are relevant to protective immunity in high-endemic areas. Methods: We analysed responses to 23 Mtb antigens in a total of 1247 subjects with different HIV and TB status across 5 geographically diverse sites in Africa (South Africa, The Gambia, Ethiopia, Malawi and Uganda). We used a 7-day whole blood assay followed by IFN-γ ELISA on the supernatants. Antigens included PPD, ESAT-6 and Ag85B (dominant antigens) together with novel resuscitation-promoting factors (rpf), reactivation proteins, latency (Mtb DosR regulon-encoded) antigens, starvation-induced antigens and secreted antigens. Results: There was variation between sites in responses to the antigens, presumably due to underlying genetic and environmental differences. When results from all sites were combined, HIV- subjects with active TB showed significantly lower responses compared to both TST- and TST+ contacts to latency antigens (Rv0569, Rv1733, Rv1735, Rv1737) and the rpf Rv0867; whilst responses to ESAT-6/CFP-10 fusion protein (EC), PPD, Rv2029, TB10.3, and TB10.4 were significantly higher in TST+ contacts (LTBI) compared to TB and TST- contacts fewer differences were seen in subjects with HIV co-infection, with responses to the mitogen PHA significantly lower in subjects with active TB compared to those with LTBI and no difference with any antigen. Conclusions: Our multi-site study design for testing novel Mtb antigens revealed promising antigens for future vaccine development. The IFN-γ ELISA is a cheap and useful tool for screening potential antigenicity in subjects with different ethnic backgrounds and across a spectrum of TB and HIV infection states. Analysis of cytokines other than IFN-γ is currently on-going to determine correlates of protection, which may be useful for vaccine efficacy trials.
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    Elucidation of a human urine metabolite as a seryl-leucine glycopeptide and as a biomarker of effective anti-tuberculosis therapy
    (American Chemical Society, 2018-12-26) Fitzgerald, Bryna L.; Islam, M. Nurul; Graham, Barbara; Mahapatra, Sebabrata; Webb, Kristofor; Boom, W. Henry; Malherbe, Stephanus T.; Joloba, Moses L.; Johnson, John L.; Winter, Jill; Walzl, Gerhard; Belisle, John T.
    ENGLISH ABSTRACT: The evaluation of new tuberculosis (TB) therapies is limited by the paucity of biomarkers to monitor treatment response. Previous work detected an uncharacterized urine metabolite with a molecular mass of 874.3547 Da that showed promise as a biomarker for successful TB treatment. Using mass spectrometry combined with enzymatic digestions, the metabolite was structurally characterized as a seryl-leucine core 1 Oglycosylated peptide (SLC1G) of human origin. Examination of SLC1G in urine revealed a significant abundance increase in individuals with active TB versus their household contacts and healthy controls. Moreover, differential decreases in SLC1G levels were observed by week one in TB patients during successful treatment versus those that failed treatment. The SLC1G levels were also associated with clinical parameters used to measure bacterial burden (GeneXpert) and inflammation (positron emission tomography-computed tomography (PET-CT)). These results demonstrate the importance of metabolite identification and provide strong evidence for applying SLC1G as a biomarker of TB treatment response.
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    A serum circulating miRNA signature for short-term risk of progression to active tuberculosis among household contacts
    (Frontiers Media, 2018) Duffy, Fergal J.; Thompson, Ethan; Downing, Katrina; Suliman, Sara; Mayanja-Kizza, Harriet; Boom, W. Henry; Thiel, Bonnie; Weiner III, January; Kaufmann, Stefan H. E.; Dover, Drew; Tabb, David L.; Dockrell, Hazel M.; Ottenhoff, Tom H. M.; Tromp, Gerard; Scriba, Thomas J.; Zak, Daniel E.; Walzl, Gerhard; GC6-74 Consortium
    ENGLISH ABSTRACT: Biomarkers that predict who among recently Mycobacterium tuberculosis (MTB)-exposed individuals will progress to active tuberculosis are urgently needed. Intracellular microRNAs (miRNAs) regulate the host response to MTB and circulating miRNAs (c-miRNAs) have been developed as biomarkers for other diseases. We performed machine-learning analysis of c-miRNA measurements in the serum of adult household contacts (HHCs) of TB index cases from South Africa and Uganda and developed a c-miRNA-based signature of risk for progression to active TB. This c-miRNA-based signature significantly discriminated HHCs within 6 months of progression to active disease from HHCs that remained healthy in an independent test set [ROC area under the ROC curve (AUC) 0.74, progressors < 6 Mo to active TB and ROC AUC 0.66, up to 24 Mo to active TB], and complements the predictions of a previous cellular mRNA-based signature of TB risk.